This course is designed for individuals in local. State
and regional programs who are, or expect to be, involved
in designing and conducting operator training courses.

The course stresses technical content of operator
interest.   Course content is intended to be used in the
preparation of lesson plans for operator training or as
background information for discussion purposes.

The manuals are prepared in limited numbers for use
of the class,  and hence should not be cited in
bibliographies as appearing periodically.
          Office of Water Programs
                 April, 1972

   Title or Description

   The Aquatic Environment

   Water Quality Criteria

   Wastewater Treatment:  Schematic, Functions,  Options

   Wastewater Treatment - The Result of Natural Phenomena

   Unit Operations in Waste Treatment

   Wastewater Treatment Plant Safety Practices

   Screening - Methods and Purposes

   Grit Removal - Principles and Methods

   Flow Measurement Devices

   Sedimentation Basins in Wastewater Treatment

   Sedimentation Tank Equipment

   Causes of Reduced Efficiency in Primary Clarification

   Settling Tank Operations

   Anaerobic Process Principles

   Anaerobic Industrial Waste Applications

   Factors Affecting Digester Efficiency

   Aerobic Digestion

   Activated Sludge Waste Treatment Process Variations and Modifications

   Case Histories: Effluent Excellence from Presently Available
   Secondary Treatment Processes

   Trickling Filters

   Experience in the Use of Raw Sewage Lagoons

   Sampling in Water Quality Studies

   Sampling in Treatment Plant Operations

   Determining Efficiency of Settling Tanks and Clariflers
Outline Number

























Title or Description
Testing as a Tool for Digest Operation

Significance of Bacteriologic Data

Examination of Water for Coliform and Fecal
Streptococcus Groups

Membrane Filter Laboratory and Field Procedures

Dissolved Oxygen Determination (DO) - I
Azide Modification, lodometric  Titration

Dissolved Oxygen Determination - II
Electronic Measurements

BOD Procedures for Treatment Plant Operations

Effect of Some Variables on the BOD Test

Chemical Oxygen Demand and COD/BOD Relationships

Pumps Maintenance

Ultimate Disposal to the Environment

Chlorine Determinations and Their Interpretation

Wastewater Disinfection

Methods Which May Be Used to  Detect Industrial Waste Problems

The Model Sewer Ordinance

Training for Wastewater Treatment Plant Operations

Evaluation of Wastewater Treatment Programs


Computation Check Charts (5)
Outline Number



















                                THE AQUATIC ENVIRONMENT

                           Part 1:  The Nature and Behavior of Water

 The  earth is physically divisible into the
 lithosphere or land masses, and the
 hydrosphere which includes the  oceans,
 lakes, streams, and subterranean waters.

 A  Upon the hydrosphere are based a number
    of sciences which represent different
    approaches.  Hydrology is  the general
    science of water  itself with its various
    special fields such as hydrography,
    hydraulics, etc.  These in  turn merge
    into physical chemistry  and chemistry.

 B  Limnology and  oceanography combine
    aspects of all of these, and deal not only
    with the physical liquid water and its
    various naturally occurring solutions and
    forms, but also with living organisms
    and the infinite interactions that occur
    between them and their environment.

    Water quality management, including
    pollution control, thus looks to all
    branches of aquatic science   in efforts
    to coordinate and improve man's
    relationship  with his aquatic environment.

 A  Water is the only abundant liquid on our
     planet.  It  has  many properties most
     unusual for liquids,  upon which depend
     most of the familiar aspects of the world
     about us as we know it.
                                            TABLE 1
                                 UNIQUE PROPERTIES OF WATER
          Highest heat capacity (specific heat) of any
          solid or liquid (except NH )
Stabilizes temperatures of organisms and
geographical regions
          Highest latent heat of fusion (except NH.)
Thermostatic effect at freezing point
          Highest heat of evaporation of any substance
Important in heat and water transfer of
         The only substance that has its maximum
         density as a liquid (4°C)
Fresh and brackish waters have maximum
density above freezing point.  This is
important in vertical circulation pattern
in lakes.
          Highest surface tension of any liquid
Controls surface and drop phenomena,
important in cellular physiology
          Dissolves more substances in greater
          quantity than any other liquid
Makes complex biological system possible.
Important for transportation of materials
in solution.
          Pure water has the highest di-electric
          constant of any liquid
Leads to high dissociation of inorganic
substances in solution
          Very little electrolytic dissociation
Neutral, yet contains both H+ and OH  ions
          Relatively transparent
Absorbs much energy in infra red and ultra
violet ranges, but little in visible range.
Hence "colorless"

The Aquatic Environment
B  Physical Factors of Significance

   1  Water substance

     Water is not simply "HO" but in
     reality is a mixture of some 33
     different substances involving three
     isotopes each of hydrogen and oxygen
     (ordinary hydrogen H ,  deuterium H ,
     and tritium H ; ordinary oxygen O^
     oxygen 17, and oxygen 18) plus 15 known
     types of ions. The molecules of a
     water mass tend to associate themselves
     as polymers rather than to remain as
     discrete units.  (See Figure 1)
2  Density

   a Temperature and density:  Ice.
     Water is the only known substance
     in which the solid state will float
     on the liquid state. (See Table 2)
                             SUBSTANCE OF  WATER
                                        Figure 1

                                                                The Aquatic Environment
                TABLE 2

Temperature (° C)

- 8
- 6
- 4
- 2
. 00997
Ice **

*  Tabular values for density, etc.,  represent
   statistical estimates by various workers
   rather than absolute values, due to the
   variability of water.

** Regular ice is known as "ice I".   Four or
   more other "forms" of ice are known to
   exist (ice II,  ice HI, etc.), having densities
   at  1 atm. pressure  ranging from  1.1595
   to  1.67.  These are of extremely  restricted
   occurrence and may be ignored in most
   routine operations.

           This  ensures that ice usually
           forms on top of a body of  water
           and tends to insulate the remain-
           ing water mass from further loss
           of heat.   Did ice sink, there
           could be little or no carryover of
           aquatic life from season to season
           in the higher latitudes. Frazil or
           needle ice forms colloidally at a
           few thousandths of a degree
           below DO C.  It is adhesive and
           may  build up on submerged objects
           as "anchor ice", but it is still
           typical ice.
1)  Seasonal increase in solar
    radiation annually warms
    surface waters in summer
    while other factors result in
    winter  cooling.  The density
    differences resulting estab-
    lish two classic layers: the
    epilimnion or surface layer,
    and the hypolimnion or lower
    layer,  and in between is the
    thermocline or shear-plane.

2)  While for certain theoretical
    purposes a thermocline is
    defined as a zone in which the
    temperature changes one
    degree centigrade for each
    meter of depth, in practice,
    any transitional layer between
    two relatively stable masses
    of water of different temper-
    atures  (and probably other
    qualities too) may be regarded
    as a thermocline.

3)  Obviously the greater the
    temperature differences
    between epilimnion and
    hypolimnion and the sharper
    the gradient in  the thermocline,
    the more stable will the
    situation be.

4)  From information given above,
    it should be evident that while
    the temperature of the
    hypolimnion rarely drops
    much below 4°  C, the
    epilimnion may range from
    DO C upward.

5)  It should also be emphasized
    that when epilimnion  and
    hypolimnion achieve the same
    temperature, stratification no
    longer  exists,  and the entire
    body of water behaves
    hydrologically as a unit, and
    tends to assume uniform
    chemical and physical
    characteristics. Such periods
    are called overturns and

The Aquatic Environment
              usually result in considerable
              water quality changes of
              physical, chemical, and
              biological significance.

          6)   When stratification is present,
              however, each layer behaves
              relatively independently, and
              considerable quality differences
              may  develop.

          7)   Thermal stratification as
              described above has no
              reference to the size of the
              water mass;  it is found in
              oceans and puddles.

          8)   The relative densities of the
              various isotopes of water also
              influence its molecular  com-
              position. For example,  the
              lighter O,g tends to go off
              first in the process of
              evaporation,  leading to  the
              relative enrichment of air by
              O^g and the enrichment of
              water by O17 and O^Q.  This
              can lead to a measurably
              higher Olg content in warmer
              climates.  Also, the temper-
              ature of water in past geologic
              ages can be closely estimated
              from the ratio of 0^9 in tne
              carbonate of mollusc shells.

       b  Dissolved and/ or suspended solids
          may also affect the density of
          natural waters.

                TABLE 3
               ON DENSITY
Dissolved Solids
(Grams per liter)
(at 40 C)
                       c  Density caused stratification

                          1)   Density differences produce
                              stratification which may be
                              permanent, transient,  or

                          2)   Permanent stratification
                              exists for example where
                              there is a heavy mass of
                              brine in the deeper areas  of
                              a basin which does not respond
                              to seasonal or other changing

                          3)   Transient stratification may
                              occur with the recurrent
                              influx of tidal water in an
                              estuary for example, or the
                              occasional influx of cold
                              muddy water into a deep lake
                              or  reservoir.

                          4)   Seasonal stratification involves
                              the annual establishment of
                              the epilimnion,  hypolimnion,
                              and thermocline as described
                              above.   The spring and  fall
                              overturns of such waters
                              materially affect biological
                          5)  Density stratification is not
                             limited to two-layered systems;
                             three, four,  or even more
                             layers may be encountered in
                             larger bodies of water.
                          ,A "plunge line" may develop at
                          the mouth of a stream.  Heavier
                          water flowing into a lake or
                          reservoir plunges below the
                          lighter water mass of the epiliminium
                          to flow along at a lower level.  Such
                          a line is usually marked by an
                          accumulation of floating debris.
    35 (mean for sea water)

                                                             The Aquatic Environment
         The viscosity of water is greater at
         lower temperatures (see Table 4).
         This is important not only in situations
         involving the control of flowing water
         as in a sand filter, but  also since
         overcoming resistance  to flow gen-
         erates heat,  it is  significant in the
         heating of water by internal friction
         from wave and current  action.
         Living organisms more  easily support
         themselves in the more  viscous
         (and also denser)  cold waters of the
         arctic than in the  less viscous warm
         tropical waters.
                   TABLE 4

VISCOSITY OF WATER (In millipoises at  1 atm)
Temp, o C
- 5
Dissolved solids in g/L
18. 1
8. 1
-- --
      3  Surface tension has biological as well
         as physical significance.   Organisms
         whose body surfaces cannot be wet by
         water can either ride on the surface filnr.
         or in some instances may be "trapped"
         on the surface film and be unable to
         re-enter the water.
4  Incident solar radiation is the prime
   source of energy for virtually all
   organic and most inorganic processes
   on earth.  For the earth as a whole,
   the total amount (of energy) received
   annually must exactly balance that
   lost by reflection and radiation into
   space if climatic and related con-
   ditions are to remain relatively
   constant over geologic time.

   a  For a given body of water,
      immediate sources of energy
      include in addition to solar
      irradiation: terrestrial heat,
      transformation of kinetic energy
      (wave and current action) to heat,
      chemical and biochemical
      reactions,  convection from the
      atmosphere,  and condensation of
      water vapor.

   b  The proportion of light reflected
      depends on the angle of incidence,
      the temperature, color,  and other
      qualities of the water.  In general,
      as the depth increases arithmet-
      ically, the light tends to decrease
      geometrically.  Blues,  greens,
      and yellows tend to penetrate most
      deeply while ultra violet,  violets,
      and orange-reds are most quickly
      absorbed.  On the order of 90%
      of the total illumination which
      penetrates the surface film is
      absorbed in the first 10 meters of
      even the clearest water, thus
      tending to warm the upper layers.

5  Water movements

   a  Waves or rhythmic movement

      The best known are traveling
      waves caused by wind.  These are
      effective only against objects near
      the surface.  They have little
      effect on the movement of large
      masses of water.

    Standing waves or seiches occur
    in lakes, estuaries,  and other
    enclosed bodies of water,  but are
    seldom large enough to be
    observed.  An "internal wave or
    seich" is an oscillation in a
    submersed mass of water such
    as a hypolimnion, accompanied
    by compensating oscillation in the
    overlying water such that no
    significant change in surface level
    is detected.  Shifts in submerged
    water masses of this type can have
    severe effects on the biota and
    also on human water uses where
    withdrawals are confined to a given
    depth.  Descriptions and analyses
    of many  other types  and sub-types
    of waves and wave-like movements
    may be found in the literature.
 b  Tides

    Tides are the longest waves known
    in the ocean, and are evident along
    the coast by the rhythmic rise and
    fall of the water.  While part and
    parcel of the same phenomenon, it
    is often convenient to refer to the
    rise and fall of the water level as
    "tide",  and to the accompanying
    currents as "tidal currents".

    Tides are basically caused by the
    attraction of the sun and moon on
     water masses,  large and small;
     however, it is only  in the oceans
     and certain of the larger lakes that
     true tidal action has been demonstrated.
     The patterns of tidal action are
     enormously complicated by local
     topography, interaction with seiches,
     and other factors.  The literature
     on tides is very large.

   c  Currents (except tidal currents)
      are steady a rhythmic water
      movements which have had major
      study only in oceanography although
      they are best known from rivers
      and streams.  They primarily are
   concerned with the translocation of
   water masses.  They may be
   generated internally by virtue of
   density changes, or externally by
   wind or terrestrial topography.
   Turbulence phenomena or eddy
   currents  are largely responsible for
   lateral mixing in a current.  These
   are of far more importance in the
   economy  of a body of water than
   mere laminar flow.

d  Coriolis force is a result of inter-
   action between the rotation of the
   earth, and the movement of masses
   or bodies on the earth.  The net
   result is  a slight tendency for moving
   objects to veer  to the  right in the
   northern hemisphere, and to the
   left in the southern hemisphere.
   While the result in fresh waters is
   usually negligible, it may be con-
   siderable in marine waters.  For
   example,  other factors permitting,
   there is a tendency in estuaries for
   fresh waters to move toward the
   ocean faster along the right bank,
   while salt tidal waters tend to
   intrude farther inland along the
   left bank.  Effects are even more
   dramatic in the open oceans.

 e  Langmuir circulation (or L. spirals)
    is the interlocking rotation of
    somewhat cylindrical masses of
    surface water  under  the influence
    of wind  action.  The axes of the
    cylinders are parallel to the
    direction of the wind.

    To somewhat oversimplify the
    concept, a series of adjoining cells
    might be thought of as chains of
    interlocking gears in which at every
    other contact  the teeth  are rising
    while at the alternate contacts, they
     are sinking (Figure  2).

     The result is elongated masses of
     waste rising or sinking together.
     This produces the familiar "wind
     rows"  of foam,  flotsam and jetsam,
     or plankton often seen  streaking

                                                         The Aquatic Environment
windblown lakes or oceans.  Certain
zoo-plankton struggling to maintain
a position near the surface often
collect in the down current between
two Langmuir cells, causing such
an area to be called the "red dance",
while the clear upwelling water
between  is the "blue dance".

This phenomenon may be important
in water or plankton sampling  on
a windy day.

The pH of pure water has been deter-
mined between 5. 7 and 7.01 by various
workers.  The latter value  is most
widely accepted at the present  time.
Natural waters of course vary  widely
according to circumstances.
The elements of hydrology mentioned
above represent a selection of some of
the more conspicuous physical factors
involved in working with water quality.
Other items not specifically mentioned
include: molecular structure of waters,
interaction of water and radiation.
internal pressure,  acoustical charac-
teristics,  pressure-volume -temperature
relationships,  refractivity, luminescence,
color,  dielectrical characteristics and
phenomena, solubility, action and inter-
actions of gases, liquids and solids,
water vapor, ices, phenomena of
hydrostatics and hydrodynamics in general.

                                         1  Bus well,  A.M. and Rodebush,  W.H.
                                              Water.  Sci. Am.   April 1956.

                                         2  Dorsey, N. Ernest.   Properties of
                                              Ordinary Water - Substance.
                                              Reinhold Publ.  Corp.  New York.
                                              pp.  1-673.  1940.

                                         3  Hutcheson, George E.  A Treatise on
                                              Limnology.   John Wiley Company.

                              THE AQUATIC ENVIRONMENT

                    Part 2: The Aquatic Environment as an Ecosystem

 Part 1 introduced the lithosphere and the
 hydrosphere.  Part 2 will deal with certain
 general aspects of the biosphere, or the
 sphere of life on this earth, which photo-
 graphs from space have shown is a finite
 globe in infinite space.

 This is the habitat of man and the other
 organisms.  His relationships  with the
 aquatic biosphere are our common concern.

 A  We can only  imagine what this world
    must have been like before there was life.

 B  The world as we know it is largely shaped
    by the forces of life.

    1   Primitive forms of life created organic
       matter and  established soil.

    2   Plants  cover the lands and enormously
       influence the forces of erosion.

    3   The nature  and  rate of erosion affect
       the redistribution of materials
       (and mass)  on the surface of the
       earth (topographic changes).

    4   Organisms  tie up vast quantities of
       certain chemicals, such as carbon
       and oxygen.

    5   Respiration of plants and animals
       releases  carbon dioxide  to the
       atmosphere in influential quantities.

    6   CO_ affects the heat transmission of
       the atmosphere.

 C  Organisms respond to and in turn affect
    their environment.  Man is  one of the
    most influential.

 A  The ecosystem is the basic functional
    unit of ecology.  Any area of nature that
    includes living organisms and nonliving
    substances interacting to produce an
    exchange of materials between the living
    and nonliving parts constitutes and
    ecosystem.  (Odum,  1959)

    1  From a structural standpoint, it is
       convenient to recognize four
       constituents as  composing an
       ecosystem (Figure 1).

       a  Abiotic NUTRIENT NUMERALS
          which are the physical stuff of
          which living protoplasm will be

       b  Autotrophic (self-nourishing) or
          PRODUCER organisms.  These
          are largely the green plants
          (holophytes), but other minor
          groups must also be included
          (See Figure 2). They assimilate
          the nutrient minerals, by the use
          of considerable energy,  combine
          them into living organic substance.

       c  Heterotrophic (other-nourishing)
          CONSUMERS (holozoic). are chiefly
          the animals.   They ingest (or eat)
          and digest organic matter, releasing
          considerable energy in the process.

       d Heterotrophic REDUCERS are chiefly
          bacterial and fungi that return
          complex organic compounds back to
          the original abiotic mineral condition,
          thereby releasing the remaining
          chemical energy.

    2   From a functional standpoint, an
       ecosystem has two parts (Figure 2)

The Aquatic Environment
                                CO NSUMERS
        PRO DUCERS
                                       FIGURE 1
   a The autotrophic or producer
     organisms, which construct
     organic substance.

   b The heterotrophic or consumer and
     reducer organisms which destroy
     organic substance.

3  Unless the autotrophic and hetero-
   trophic phases of the cycle approximate
   a dynamic equilibrium, the ecosystem
   and the environment will change.

Each of these groups includes simple,
single-celled representatives, persisting
at lower levels on the evolutionary stems
of the higher organisms. (Figure 2)

1  These groups span the gaps between the
   higher kingdoms with a multitude of
   transitional forms.  They are collectively
   called the PROTISTA.
2  Within the protista, two principal sub-
   groups can be defined on the basis of
   relative complexity of structure.

   a The bacteria and blue-green algae,
     lacking a nuclear membrane may
     be considered as the lower protista
     (or Monera).

   b The single-celled algae and
     protozoa are best referred to as
     the higher protista.

Distributed throughout these groups will
be found most of the traditional "phyla"
of classic biology.
                                             IV   FUNCTIONING OF THE ECOSYSTEM

                                              A  A food chain is the transfer of food energy
                                                 from plants through a series of organisms
                                                 with repeated eating and being eaten.
                                                 Food chains are not isolated sequences but
                                                 are interconnected.

                                                           The Aquatic Environment

          Energy Flows from Left to Right, General Evolutionary Sequence is Upward

    PRODUCERS    |

 Organic Material Produced,
 Usually by Photosynthesis I
                         Organic Material Ingested or
                             Digested Internally

Organic Material Reduced
by Extracellular Digestion
and Intracellular Metabolism
to Mineral Condition
                           ENERGY RELEASED
Flowering Plants and
Club Mosses, Ferns
Liverworts, Mosses
Multicellular Green
Red Algae
Brown Algae
Segmented Worms


Fungi Imperfecti

Higher Phycomycetes

               H   I  G" H  E  R      PROTISTA
Unicellular Green Algae
Pigmented Flagellates
Amoeboid Cilliated
Flagellated, Suctoria
(Chytridiales, et. al. )
                LOWER       PROTISTA
                               (or:   Monera)

                                      I                   Actinomycetes

Blue Green Algae

       Phototropic Bacteria

              Chemotropic Bacteria
  Bl.ECO.pl.2a. 1. 69
                                FIGURE 2

The Aquatic Environment
B  A food web is the interlocking pattern of
   food chains in an ecosystem.  (Figures  3, 4)
   In complex natural communities,  organisms
   whose food is obtained by the same number
   of steps are  said to belong to the same
   trophic (feeding) level.

C  Trophic Levels

   1  First - Green plants (producers)
      (Figure 5) fix biochemical energy and
      synthesize basic organic substances.

   2  Second - Plant eating animals (herbivores)
      depend on the producer organisms for

   3  Third  - Primary carnivores,  animals
      which  feed on herbivores.

   4  Fourth - Secondary carnivores feed on
      primary carnivores.

   5  Last - Ultimate carnivores are the last
      or ultimate level of consumers.
D  Total Assimilation

   The amount of energy which flows through
   a trophic  level is distributed between the
   production of biomass and the demands of
   respiration in a ratio of approximately

E  Trophic Structure of the Ecosystem

   The interaction of the food chain
   phenomena (with energy loss at each
   transfer)  results in various communities
   having definite trophic  structure or energy
   levels.  Trophic structure may be
   measured and described either in terms
   of the standing crop per unit area or in
   terms of energy fixed per unit area per
   unit time  at successive trophic levels.
   Trophic structure and function can be
   shown graphically by means of ecological
   pyramids (Figure 5).
         Figure 3. Diagram of the pond ecosystem. Basic units are as follows: I, abiotic substances-basic inorganic and
         organic compounds; HA, producers-rooted vegetation; IIB, producers-phytoplankton; IIMA, primary consumers
         (herbivores)-bottom ronnij IIMB. primary consumeri (herbivores)-zooplankton; III-2. secondary consumers (car-
         •lvorcs)i III-3, tertiary consumers (seconduy carnivores); IV, decornpoiers-bacteriv and fungi of decay.

                                                       The Aquatic Environment
Figure 4.  A MARINE ECOSYSTEM (After Clark, 1954 and Patten, 1966)

 The Aquatic Environment

Decomposers [1 Carnivores (Secondar
n Carnivores (Primary
1 ] Herbivores
1 Producers |

\ \

                                                              The Aquatic Environment

1  Clarke,  G. L.   Elements of Ecology.
      John Wiley & Sons, New York.   1954.

2  Cooke, W.B.   Trickling Filter Ecology.
      Ecology 40(2):273-291.   1959.

3  Hanson,  E. D.   Animal Diversity.
      Prentice-Hall,  Inc., New Jersey.  1964.

4  Hedgpeth,  J.W.   Aspects  of the Estuarine
      Ecosystem.  Amer. Fish. Soc., Spec.
      Publ. No. 3.   1966.
 5  Odum,  E.P.  Fundamentals of Ecology.
      W.B. Saunders Company,
      Philadelphia and London.   1959.

 6  Patten, B.C.   Systems Ecology.
      Bio-Science.   16(9).   1966.

 7  Whittaker,  R.H. New Concepts of
      Kingdoms.  Science 163:150-160. 1969.
This outline was prepared by H. W. Jackson,
Chief Biologist,  National Training Center,
Water Quality Office,  EPA,  Cincinnati, OH 45226.

                             THE AQUATIC ENVIRONMENT

                          Part 3.  The Freshwater Environment

 The freshwater environment as considered
 herein refers to those inland waters not
 detectably diluted by ocean waters,  although
 the lower portions of rivers are subject to
 certain tidal flow effects.

 Certain atypical inland waters such as saline
 or alkaline lakes,  springs, etc.,  are not
 treated,  as the main objective is  typical
 inland water.

 All waters have certain basic biological cycles
 and types of interactions most of  which have
 already been presented.  Hence this outline
 will concentrate on aspects essentially
 peculiar to fresh inland waters.

 A The history of a body of water determines
   its present condition.  Natural waters have
   evolved in the course of geologic time
   into what we know today.

 B Streams

   In the course of their evolution, streams
   in general pass through four general
   stages of development which may be
   called: birth, youth, maturity, and old

   1   Establishment or birth.  In an extant
       stream, this might be a "dry run" or
       headwater stream-bed,  before it  had
       eroded down to the level of ground

   2   Youthful streams; when the stream-
       bed is eroded below the ground water
       level, spring water enters and the
       stream becomes permanent.
   3   Mature streams; have wide valleys,
      a developed flood plain, deeper,
      more turbid,  and usually warmer
      water,  sand,  mud,  silt, or clay
      bottom materials which shift with
      increase in flow.

   4   In old age,  streams have approached
      geologic base level. During  flood
      stage they  scour their beds and deposit
      materials on the flood plain which
      may be very broad  and flat.  During
      normal flow the channel is refilled
      and many shifting bars are developed.
      (Under the  influence of man this
      pattern may be broken up,  or
      temporarily interrupted.  Thus an
      essentially "youthful" stream might
      take on some of the characteristics
      of a  "mature" stream following soil
      erosion,  organic enrichment, and
      increased surface runoff.  Correction
      of these conditions  might likewise be
      followed by at least a partial reversion
      to the "original" condition).

C  Lakes and Reservoirs

   Geological factors which significantly
   affect the nature of either a stream or
   lake include the following:

   1   The  geographical location of  the
      drainage basin or watershed.

   2   The  size and  shape  of the drainage

   3   The  general topography, i.e.,
      mountainous or plains.

   4   The  character of the bedrocks and

   5   The  character, amount, annual
      distribution,  and rate of precipitation.

 The Aquatic Environment
   6  The natural vegetative cover of the
      land is of course responsible to many
      of the above factors and is also
      severely subject to the whims of
      civilization.  This is one of the major
      factors determining runoff versus
      soil absorption,  etc.

D  Lakes have a developmental history which
   somewhat parallels that of streams.

   1  The method of formation greatly
      influences the character and sub-
      sequent history of lakes.

   2  Maturing or natural eutrophication of

      a  If not  already present shoal areas
         are developed through erosion of
         the shore by wave action and

      b  Currents produce bars across  bays
         and thus cut off irregular areas.

      c  Silt brought in by tributary streams
         settles out in the quiet lake  water.

      d  Rooted aquatic plants grow on
         shoals and bars, and in doing so
         cut off bays and contribute to the
         filling of the lake.

      e  Dissolved carbonates and other
         materials are precipitated in the
         deeper portions of the lake in part
         through the action of plants.

      f   When  filling is  well advanced,
         mats of sphagnum moss may extend
         outward from the shore.  These
         mats are followed by sedges and
         grasses which finally convert the
         lake into a marsh.

   3   Extinction of lakes. After  lakes reach
      maturity, their progress toward
      filling up is accelerated.   They become
      extinct through:

      a  The downcutting of the  outlet.
           Filling with detritus eroded from
           the shores or brought in by
           tributary streams.

           Filling by the accumulation of the
           remains of vegetable materials
          growing in the lake itself.
           (Often two or three processes may
           act concurrently)

 A  Fresh waters in general and under
    natural conditions by definition have a
    lesser supply of dissolved substances
    than marine waters, and thus a lesser
    basic potential for the growth of aquatic
    organisms.  By the same token, they
    may be said to be more sensitive to the
    addition of extraneous materials
    (pollutants, nutrients, etc.) The
    following notes are directed toward
    natural geological and other environ-
    mental factors as they affect the
    productivity of fresh waters.

 B  Factors Affecting Stream Productivity
    (See Table 1)

                 TABLE 1
    (The productivity of sand bottoms  is
    taken as 1)
Bouom Material
Fine Gravel
Gravel and silt
Coarse gravel
Moss on fine gravel
Fissidens (moss) on coarse gravel
Ranunculus (water buttercup)
Anacharis (waterweed)
Relative Productivity
  'Selected from Tarzweli 1937
    To be productive of aquatic life,  a
    stream must provide adequate nutrients,
    light, a suitable temperature, and time
    for growth to take place.

                                                               The Aquatic Environment
   1   Youthful streams,  especially on rock
      or sand substrates are low in essential
      nutrients.  Temperatures in moun-
      tainous regions are usually low, and
      due to the steep gradient,  time for
      growth is  short. Although ample
      light is available, growth  of true
      plankton is thus greatly limited.

   2   As the  stream flows toward a more
      "mature"  condition, nutrients tend to
      accumulate, and gradient  diminishes
      and so  time of flow  increases, tem-
      perature  tends  to increase, and
      plankton flourish.

      Should  a heavy  load of inert silt
      develop on the other hand, the
      turbidity  would reduce the light
      penetration and consequently  the
      general plankton production would

   3   As the  stream approaches base level
      (old age)  and the time available for
      plankton growth increases, the
      balance between turbidity, nutrient
      levels, and temperature and other
      seasonal  conditions, determines the
      overall productivity.

C  Factors Affecting the Productivity of

   1   The size,  shape, and depth of the lake
      basin.  Shallow water is more pro-
      ductive than deeper water since more
      light will reach the  bottom to stimulate
      rooted  plant growth.  As a corollary,
      lakes with  more shoreline, having
      more shallow water, are in general
      more productive.  Broad shallow lakes
      and reservoirs have the greatest
      production potential (and hence should
      be avoided for water supplies).

   2   Hard waters are generally more
      productive than soft waters as there
      are more  plant nutrient minerals
      available.  This is often greatly in-
      fluenced by the character  of the soil
      and rocks in the watershed and the
      quality and quantity of ground water
        entering the lake.  In general,  pH
        ranges of 6.8 to 8.2 appear to  be
        most productive.

                    TABLE  2
(The productivity of sand bottoms is taken as 1)
Bottom Material
Flat rubble
Block rubble
Shelving rock
Relative Productivity
    ^Selected from Tarzwell 1937

     3  Turbidity reduces productivity as
        light penetration is reduced.

     4  The presence or absence of thermal
        stratification with its semi-annual
        turnovers affects productivity by
        distributing nutrients throughout the
        water mass.

     5  Climate, temperature,  prevalence of
        ice and snow, are also  of course

  D Factors Affecting the Productivity of

     1  The productivity of reservoirs is
        governed by much the same principles
        as that  of lakes,  with the difference
        that the water level is much more
        under the control of man.  Fluctuations
        in water level can be used to de-
        liberately increase or decrease
        productivity.  This can be
        demonstrated by a comparison of
        the TVA reservoirs which practice
        a summer drawdown  with some of
        those in the west where a winter
        drawdown is the rule.

     2  The level at which water is removed
        from a  reservoir is important to the
        productivity of the stream below.

  The Aquatic Environment
        The hypolimnion may be anaerobic
        while the epilimnion is aerobic, for
        example, or the epilimnion is poor in
        nutrients while the hypolimnion is
        relatively rich.

        Reservoir discharges also profoundly
        affect the DO, temperature, and
        turbidity in the stream below a dam.
        Too much fluctuation in, flow may
        permit sections of the stream to dry,
        or provide inadequate dilution for
        toxic waste.

The productivity of lakes and impound-
ments is such a conspicuous feature that
it is often used as a convenient means of
                                              C  According to location,  lakes and
                                                 reservoirs may be classified as polar,
                                                 temperate, or tropical.  Differences in
                                                 climatic and geographic conditions
                                                 result in differences in their biology.

  A  A body of water such as a lake, stream,
     or estuary represents an intricately
     balanced system in a state of dynamic
     equilibrium.  Modification imposed at
     one point in the system automatically
     results in compensatory adjustments at
     associated points.

  B  The more thorough our knowledge of the
     entire system, the better we can judge
     where to impose control measures to
     achieve a desired result.
     1  Oligotrophic lakes are the younger,
        less productive lakes,  which are deep,
        have clear water,  and usually support
        Salmonoid fishes in their deeper waters.

     2  Eutrophic lakes are more mature,
        more turbid,  and richer.  They are
        usually shallower.  They are richer
        in dissolved solids; N,  P, and Ca are
        abundant.  Plankton is abundant and
        there is often a rich bottom  fauna.

     3  Dystrophic lakes,  such as bog lakes,
        are low in pH, water yellow to brown,
        dissolved solids,  N,  P, and Ca scanty
        but  humic materials abundant, bottom
        fauna and plankton poor,  and fish
        species are limited.

  B  Reservoirs may also be classified as
     storage and run of the river.

     1  Storage reservoirs have a large
        volume in relation to their inflow.

     2  Run of the river reservoirs  have a
        large flow-through in relation to their
        storage value.

                                             1  Chamberlin,  Thomas C. and Salisburg,
                                                   Rollin P.  Geological Processes and
                                                   Their Results.  Geology 1: pp i-xix,
                                                   and 1-654. Henry Holt  and Company.
                                                   New York.  1904.

                                             2  Frey,  David  G.  Limnology in North
                                                   America.  Univ. Wise.  Press. 1963.

                                             3  Hutcheson, George E.  A Treatise on
                                                   Limnology Vol. I   Geography, Physics
                                                   and Chemistry.  1957.  Vol.  II.
                                                   Introduction to Lake  Biology and the
                                                   Limnoplankton.   1115pp.  1967.
                                                   John Wiley Co.

                                             4  Hynes, H.B.N.  The  Ecology of Running
                                                   Waters.  Univ.  Toronto Press.
                                                   555 pp.   1970.

                                             5  Ruttner, Franz.   Fundamentals of
                                                   Limnology. University  of Toronto
                                                   Press,   pp. 1-242.  1953.

                                                               The Aquatic Environment
Tarzwell, Clarence M.   Experimental
   Evidence on the Value of Trout 1937
   Stream Improvement in Michigan.
   American Fisheries Society Trans.
   66:177-187.   1936.

U.S. Dept. of Health, Education, and
   Welfare.  Public Health Service.
   Algae and Metropolitan Wastes.
   Transactions of a seminar held
   April 27-29.  1960 at the Robert A.
   Taft  Sanitary Engineering Center,
   Cincinnati, OH.  No.  SEC TR W61-3.
8  Ward and Whipple.  Fresh Water
      Biology.  (Introduction).  John
      Wiley Company.   1918.
This outline was prepared by H. W.  Jackson,
Chief Biologist,  National Training Center,
Water Quality Office,  EPA,  Cincinnati,
OH 45226.

                                  THE AQUATIC ENVIRONMENT

         Part 4.  The Marine Environment and its Role in the Total Aquatic Environment

A  The marine environment is arbitrarily
   defined as the water mass extending
   beyond the continental land masses,
   including the plants and animals harbored
   within.   This water mass is large and
   deep, covering about 70 percent of the
   earth's surface and being as deep as
   7 miles.  The salt  content averages
   about 35 parts per  thousand.  Life extends
   to all depths.

B  The general nature of the water cycle on
   earth is  well known.  Because the rel-
   atively large surface area of the earth
   is covered with water,  roughly 70 percent
   of the earth's rainfall is  on the seas.
   (Figure 1)
               Plpir. 1.  THE W»TER CICLE

     Since roughly one third of the earth's
     rain which falls on the land is again
     recycled through  the stratosphere
     (see Figure  1 again),  the total amount
     of water washing  over the earth's surface
     is significantly greater than one third of
     the total world rainfall.  It  is thus not
     surprising to note that the  rivers which
     finally empty into the sea carry a con-
     siderable burden  of dissolved and
     suspended solids  picked up  from the  land.
     This is the substance of geological
     erosion.(Table 1)
                                                                      TABLE 1

                                                        PERCENTAGE COMPOSITION OF THE MAJOR IONS
                                                             OF TWO STREAMS AND SEA WATER

                                                      (Data from Clark, F.W.,  1924, "The Composition of River
                                                      and Lake Waters of the United Statee",  U.S. Geol. Surv.,
                                                      Prof. Paper No. 135; Harvey, H.W., 1957, "The Chemistry
                                                      and Fertility of Sea Waters", Cambridge University Press,
Delaware River
Lambertville, N.J.
Rio Grande
Laredo, Texas
30. 10
Sea Water
1. 1
1. 16
«-HCO3 0.35J
                                                    C For this presentation,  the marine
                                                       environment will be (1) described using
                                                       an ecological approach, (2)  characterized
                                                       ecologically by comparing it with fresh-
                                                       water and estuarine environments, and
                                                       (3)  considered as a functional ecological
                                                       system (ecosystem).
                                                  II  FRESHWATER,  ESTUARINE, AND
                                                     MARINE ENVIRONMENTS

                                                   Distinct differences are found in physical,
                                                   chemical, and biotic factors in going from
                                                   a freshwater to an oceanic environment.
                                                   In general, environmental factors are more
                                                   constant in freshwater (river) and oceanic
                                                   environments when compared to the highly
                                                   variable and  harsh  environments of estuarine
                                                   and  coastal waters.

                                                   A  Physical and Chemical Factors
                                                     (Figure 2)

                                                     1   Rivers

                                                     2   Estuary and coastal waters

                                                     3   Oceans

  The Aquatic Environment
Type of environment
and general direction
 of water movement
                                     Degree of instability
  B  Biotic  Factors

     1  A complex of physical and chemical
        factors determine the biotic composi-
        tion of an environment.  In general,
        the number of species in a highly
        variable environment tends to be less
        than the number in a more stable
        environment (Hedgpeth,  1966),

     2  The dominant animal species (in
        terms of total biomass)  which occur
        in estuaries are often transient,
        spending only a part of their lives in
        the estuaries.  This results in better
        utilization of a rich environment.
                            C  Zones of the Sea

                               The nearshore environment is often
                               classified in relation to tide level and
                               water depth.  The nearshore and oceanic
                               regions together are often classified in
                               relation to light penetration and water
                                  Neritic - Relatively shallow-water
                                  zone which extends from the high-
                                  tide mark to the edge of the
                                  continental shelf.  (Figure 3)

                                                         The Aquatic Environment
            Primary subdivisions of the marine habitat.
                                  Figure 3.
a  Stability of physical factors is
   intermediate between estuarine
   and oceanic environments.

b  Phytoplankters are the dominant
   producers but in some locations
   attached algae are also important
   as producers.

c  The animal consumers are
   zooplankton, nekton,  and benthic

Oceanic - The region of the ocean
beyond the continental shelf. Divided
into three parts, all relatively
poorly populated compared to the
neritic zone.
   Euphotic zone - Waters into which
   sunlight penetrates (often to the
   bottom  in the neritic zone).  The
   zone of basic productivity.  Often
   extends to 600 feet below  the
   1)  Physical factors fluctuate
       less than in the neritic zone.

   2)  Producers are the phyto-
       plankton and consumers are
       the zooplankton and nekton.
b  Bathyal zone - From the bottom
   of the euphotic zone to about
   6, 000 feet.

   1)  Physical factors relatively
       constant but light is absent.

   2)  Producers are absent and
       consumers are scarce.

c  Abyssal zone - All the sea below
   the bathyal zone.

   1)  Physical factors more con-
       stant than in bathyal zone.

   2)  Producers absent and
       consumers not as abundant
       as in the bathyal zone.

  The Aquatic Environment

 A Sea water is a most suitable environment
    for living cells, because it contains all
    of the chemical elements essential to the
    growth and maintenance of plants and
    animals.  The ratio and often the con-
    centration of the  major salts of sea water
    are strikingly similar in the cytoplasma
    and body fluids of marine organisms.
    This similarity is also evident, although
    modified somewhat in the body fluids of
    both fresh water  and terrestrial animals.
    For example, sea water may be used in
    emergencies as a substitute for blood
    plasma in man,

 B Since marine organisms have an internal
    salt content similar to that of their
    surrounding medium (isotonic condition)
    osmoregulation poses no problem.   On the
    other hand,  fresh water organisms are
    hypertonic (osmotic pressure of body
    fluids is higher than that of the  surround-
    ing water).  Hence,  fresh water animals
    must constantly expend more energy to
    keep water out (i.e., high osmotic
    pressure fluids contain more salts,  the
    action being then  to dilute this concen-
    tration with more water).

    1  Generally,  marine invertebrates are
       narrowly poikilosmotic,  i.e., the salt
       concentration of the body fluids changes
       with that of the external medium.  This
       has special significance in estuarine
       situations where salt concentrations
       of the water often vary considerably
       in short periods of time.

    2  Marine bony fish (teleosts) have lower
       salt content internally than externally
       (hypotonic). In order to prevent
       dehydration, water is ingested and salts
       are excreted through special cells in
       the gills.

 A Salinity  - The concentration of salts is
    not the same everywhere in the sea; in
    the open ocean salinity is much less
    variable than in the ever changing
    estuary or coastal water.  Organisms
    have different tolerances to salinity
    which  limit their distribution.  The
    distributions may be in large water
    masses, such as the Gulf Stream,
    Sargasso Sea, etc., or in bays and

    1   In general,  animals in the estuarine
        environment are able to withstand
        large and rapid changes in salinity
        and temperature.  These animals are
        classified as:

        a   Euryhaline ("eury" meaning wide) •
           wide tolerance to salinity changes.
 Fresh Water
  Figure 4. Salinity Tolerance of Organisms
       b  Eurythermal - wide tolerance to
          temperature changes.

                                                               The Aquatic Environment

   L. t-udis
0   L. ohtusata
Q   L. littorea


o   Chthamalus stellatus
®   Balanus balanoides
/S   B. perforatus
                                                                ^  -'"•*?'<£'*$ **
                                                                &°Z,.*  &?^
                                                                 •":•••• -->A? n °
                                                             O;- ;.,^f> n  0 & ' •"."
                                      Figure 5
            Zonation of plants,  snails, and barnacles on a rocky shore.  While
            this diagram is based on the situation on the southwest coast of
            England, the general idea of zonation may be applied to any temper-
            ate rocky ocean shore,  though the species will differ. The gray
            zone consists largely of lichens.  At the left is the  zonation of rocks
            with exposure too extreme to support algae; at the right,  on a less
            exposed situation,  the animals are mostly obscured by the algae.
            Figures at the right hand  margin refer to the percent of time that
            the zone is exposed to the air, i.e.,  the time  that the tide is out.
            Three major zones can be recognized: the Littorina zone (above the
            gray zone);  the Balanoid  zone (between the gray zone and the
            laminarias);  and the Laminaria zone.  a. Pelvetia canaliculata;
            b. Fucus spiralis; c. Ascophyllum nodosum; d.  Fucus serratus;
            c. Laminaria digitata. (Based on Stephenson)

 The Aquatic Environment
   2  In general, animals in river and
      oceanic environments cannot withstand
      large and rapid changes in salinity and
      temperature.  These animals are
      classified as:

      a Stenohaline ("steno" meaning narrow)
        narrow tolerance to salinity changes.

      b Stenothernal - narrow tolerance to
        temperature changes.

   3  Among euryhaline animals, those living
      in lowered salinities  often have a
      smaller maximum size than those of
      the same  species living in more saline
      waters. For example, the lamprey
      (Petromyzon marinus) attains a length
      of 30 - 36" in the sea, while in the
      Great  Lakes the length is 18 -  24".

   4  Usually the larvae of marine organisms
      are more sensitive to changes  in salinity
      than are the adults.   This character-
      istic limits both the distribution and
      size of populations.

B  Tides

   Tidal fluctuation is a phenomenon unique
   to the seas (with minor exceptions).  It is
   a twice daily rise and fall in the sea level
   caused by the complicated interaction of
   many factors including sun,  moon, and the
   daily rotation of the earth.  Tidal heights
   vary from day to day and place to place,
   and are often accentuated by local
   meteorological conditions.  The rise and
   fall may range from a few inches  or less
   to fifty feet or more.

 The sea is in continuous  circulation.  With-
 out circulation, nutrients of the ocean would
 eventually become a part of the bottom and
 biomass production would cease.  Generally,
 in all oceans there exists a warm  surface
 layer which overlies the  colder water and
 forms a two-layer system of persistent
 stability.  Nutrient concentration is usually
 greatest in the lower zone.  Wherever a
 mixing or disturbance of these two  layers
 occurs, biomass production is greatest.
 Factors causing this breakup are, therefore,
 of utmost  importance concerning productivity.


 This outline contains selected material
 from  other outlines prepared by C. M.
 Tarzwell, Charles L.  Brown,  Jr.,
 C.G.  Gunnerson,  W. Lee  Trent, W.B.
 Cooke, B. H.  Ketchum, J. K. McNulty,
 J. L.  Taylor,  R. M.  Sinclair,  and others.


 1  Harvey, H.W.   The Chemistry and
        Fertility of Sea Water (2nd Ed.).
        Cambridge Univ.  Press, New York.
        234pp.  1957.

 2  Hedgpeth,  J.W. (Ed.).  Treatise on
        Marine Ecology and Paleoecology.
        Vol.  I.  Ecology   Mem. 67  Geol.
        Soc.  Amer., New  York.  1296pp.

 3  Hill, M.N.  (Ed.).   The Sea.  Vol.  II.
        The Composition of Sea Water
        Comparative and Descriptive
        Oceanography.  Interscience Publs.
        John Wiley & Sons, New York.
        554pp.   1963.

 4  Moore, H.B.   Marine Ecology.   John
        Wiley & Sons, Inc.,  New York.
        493 pp.   1958.

 5  Reid,  G. K.  Ecology  of Inland Waters
        and Estuaries.  Reinhold Publ.
        Corp.  New York.   375pp.   1961.

 6  Sverdrup,  Johnson, and Fleming.
        The Oceans.  Prentice-Hall, Inc.,
        New York.   1087  pp.   1942.
This outline was prepared  by H.W. Jackson,
Chief Biologist, National Training Center,
Water Quality Office. EPA, Cincinnati, OH

                               THE AQUATIC ENVIRONMENT

                                   Part 5:  Tidal Marshes
The Marsh and the
 A  "There is no other case in nature,  save
    in the coral reefs, where the adjustment
    of organic relations to physical condition
    is seen in such a beautiful way as the
    balance between the growing marshes
    and the tidal streams by which they are
    at once nourished and worn away. "
    (Shaler,  1886)

 B  Estuarine pollution studies are usually
    devoted to the dynamics of the circulating
    water, its chemical, physical, and
    biological parameters,  bottom deposits,  etc.

 C  It is easy to overlook the intimate relation-
    whips which exist between the bordering
    marshland, the moving waters,  the tidal
    flats,  subtidal deposition,  and seston
    whether of local,  oceanic, or riverine

 D  The tidal marsh (some  inland areas also
    have salt marshes) is generally considered
    to be the marginal areas of estuaries and
    coasts in the intertidal  zone which are
    dominated by  emergent vegetation.  They
    generally extend  inland to the farthest
    point reached by  the spring tides, where
    they merge into freshwater swamps and
    marshes (Figure 1).  They may range in
    width from nonexistent  on rocky coasts to
    many kilometers.

A In general,  marsh substrates are high in
   organic content,  relatively low in minerals
   and trace elements.  The upper layers
   bound together with living roots called
   turf,  underlaid by more compacted peat
   type material.
Rising or eroding coastlines may
expose peat from ancient marsh
growth to wave action which cuts
into the soft peat rapidly (Figure 2).
Such banks are likely to be  cliff-like,
and are often undercut.  Chunks of
peat are often found lying about on
harder substrate below high tide line.
If face of cliff is well above high water,
overlying vegetation is likely to be
typically terrestrial of the area.
Marsh type vegetation is probably

Low lying deltaic, or sinking coast-
lines, or those with low energy wave
action are likely to have  active marsh
formation in progress (Figure  3).
Sand dunes are also common in such
areas (Figure 4).  General coastal
configuration is a  factor.

a  Rugged or precipitous coasts or
   slowly rising coasts,  typically
   exhibit narrow  shelves, sea cliffs,
   fjords, massive beaches, and
   relatively less  marsh area (Figure 5).
   An Alaskan fjord subject to recent
   catastrophic subsidence and rapid
   deposition of glacial flour shows
   evidence  of the recent encroachment
   of saline  waters in the presence of
   recently buried trees and other
   terrestrial vegetation, exposure
   of layers of salt marsh peat along
   the edges of channels, and a poorly
   compacted young marsh turf developing
   at the new high water level (Figure 6),

b  Low lying coastal plains tend to be
   fringed by barrier islands, broad
   estuaries and deltas, and broad
   associated marshlands (Figure  7, 14).
   Deep tidal channels fan out through
   innumerable branching and often
   interconnecting rivulets.  The
   intervening grassy plains are
   essentially at mean high tide level.

                    Figure 1.  Zonation in a positive New England estuary.  1.  Spring tide level, 2.  Mean high tide,
                    3.  Mean low tide, 4.  Bog hole, 5.  Ice cleavage pool,  6.  Chunk of Spartina turf deposited by ice,
                    7.  Organic ooze with associated community, 8.  eelgrass  (Zostera), 9.  Ribbed mussels (modiolus)-
                    clam (mya) - mud snail (Nassa) community.  10.  Sea lettuce (Ulva)

                                                              The Aquatic Environment
Figure 2.  Diagrammatic section of eroding peat cliff

  Figure 3.  Effects of deltaic subsidence
   during distributary system abandonment
     c  Tropical and subtropical regions
        such as  Florida, the Gulf Coast,
        and Central America, are frequented
        by mangrove swamps.  This unique
        type of growth is able to establish
        itself in shallow water and move out
        into progressively deeper areas
        (Figure  8).  The strong deeply
        embedded  roots enable the mangrove
        to resist considerable wave action
        at times, and the tangle  of roots
        quickly accumulates a deep layer of
        organic  sediment.  Mangroves are
        often considered to be effective as
                                                         land builders.  When fully developed,
                                                         a mangrove swamp is an impene-
                                                         trable thicket of roots over the tidal
                                                         flat affording shelter to a sort of
                                                         semi-aquatic organism  such as
                                                         various molluscs and crustaceans,
                                                         and providing access from the
                                                         nearby land to predaceous birds,
                                                         reptiles and mammals.

                                                         Mangroves are not restricted to
                                                         estuaries, but may develop out into
                                                         shallow oceanic lagoons, or upstream
                                                         into relatively fresh waters.

 A  Measuring the productivity of grasslands
    is not easy, because grass is seldom used
    directly as such by man.  It is thus
    usually expressed as production of meat,
    milk, or in the case of salt marshes, the
    total crop of animals that obtain food per
    unit of area.  The primary producer in a
    tidal marsh is the marsh grass, but very
    little of it is used as grass.  (Table  1)

    The actual nutritional analysis of several
    marsh grasses as compared to dry land
    bay is shown  in Table 2«  A study of the
    yield of Juncus per square meter in a
    North Carolina marsh  is shown in Figure 9.

 B  The actual utilization of marsh grass is
    accomplished primarily by its decom-
    position and ingestion by micro flora and
    fauna.  A  small quantity  of seeds and
    solids is probably consumed directly by
    birds (Figure 10).

    1  The quantity of micro invertebrates which
       thrive on this wealth of decaying marsh
       hay has not been estimated, nor has the
       actual production of small fishes such
       as the top minnows  (Fundulus) which
       swarm in at high tide, or the mud
       snails (Nassa) and others.  Many  forms
       of oceanic life migrate into the estuaries,
       especially the marsh areas, for impor-
       tant portions of their life histories as
       has been mentioned  elsewhere (Figure 11).

The Aquatic Environment
                                                                    MHW -18 I300S BC

                                                                     MHW 0'  1950 5 AD
                                          Figure 4

             Development of a Massachusetts Marsh since 1300 BC, involving an
             18 foot rise in water level.  Shaded area indicates sand dunes.  Note
             meandering marsh tidal drainage.  A:  1300 BC, B:  1950 AD.

                                                               The Aquatic Environment
               Figure 5. A River Mouth on a Slowly Rising Coast.  Note absence
                       of deltaic development and relatively little marshland,
                       although mud flats stippled are extensive.
An indirect approach in Rhode Island
revealed in a single August day on a
relatively small marsh area, between
700 and 1000 wild birds of 12 species,
ranging from 100 least sandpipers to
uncountable numbers of seagulls.  One
food requirement estimate for three-
pound poultry in the confined inactivity
of a poultry yard is approximately one
ounce per pound of bird per  day.
One-hundred (100) black bellied plovers
at approximately ten (10) ounces each
would weigh on the order of  sixty (60)
pounds.  At the same rate of food
consumption, this would indicate nearly
four (4) pounds of food required for
this species alone.  The much
greater activity of the wild birds
would obviously greatly increase their
food requirements, as would their
relatively smaller size.

Considering the range of foods con-
sumed, the sizes  of the birds, and the
fact that at certain seasons, thousands
of migrating ducks and others pause
to feed here, the enormous productivity
of such a marsh can be better under-

The Aquatic Environment

        Figure 6.  Some general relationships in a northern fjord with a rising water level. 1.  mean low
                  water, 2.  maximum high tide, 3.  Bedrock, 4.  Glacial flour to depths in excess of
                  400 meters, 5. Shifting flats and channels, 6.  Channel against bedrock, 7.  Buried
                  terrestrial vegetation, 8.  Outcroppings of salt marsh peat.
                                                              CONOCARPUS       . AVICENNIA
                                                            TRANSITION ASSOCIES SALT-MARSH ASSOCIES
 Figure 7.  A Coastal Plain Marsh
             in India  subject to a high
             tidal range.
                                                                                       uHOcm.rins HOCK
Figure 8.  Diagrammatic transect of a mangrove swamp
            showing transition from marine to terrestrial

                                                                  The Aquatic Environment
TABLE 1.  General Orders of Magnitude of Gross Primary Productivity in Terms
                    of Dry Weight of Organic Matter Fixed Annually
                                         gms/M /year
 	Ecosystem	(grams/square meters/year)      Ibs/acre/year
 Land deserts,  deep oceans             Tens                        Hundreds
 Grasslands, forests,  cutrophic        Hundreds                   Thousands
    lakes, ordinary agriculture
 Estuaries,  deltas,  coral reefs.        Thousands                  Ten-thousands
    intensive agriculture (sugar
    cane, rice)
                 TABLE 2.   Analyses of Some Tidal Marsh Grasses
             T/A               Percentage Composition
            Dry Wt.      Protein    Fat       Fiber     Water      Ash      N-free Extract
            D/'slich/is sp/'cala (pure stand, dry)
             2.8         5.3      1.7        32.4      8.2        6.7          45.5
            Short Spartina altcrnillora and Salicornia curopaea (in standing water)
             1.2         7.7      2.5        31.1      8.8       12.0          37.7
            Spanina altcrnillora (tall, pure stand in standing water)
             3.5         7.6      2.0        29.0      8.3       15.5          37.3
            Spartina pai':m 
The Aquatic Environ  ent
                       5  1,400
                       „  1.000
                       z   800
              Figure 9.  Standing crop of Juncus.  Solid line represents observed
                         values; broken line represents seasonal cycle calculated
                         on the basis of an assumed constant total biomass.
   Figure 10.  The nutritive composition of
   successive stages of decomposition of
   Spartina marsh grass, showing increase
   in protein and decrease in carbohydrate
   with increasing age and decreasing size
   of detritus particles.
Figure 11.  Diagram of the life cycle
of white shrimp (after Anderson and
Lunz 1965).

                                                                The Aquatic Environment
      Greater yellow legs (left)
        and black duck
                    Great blue heron  S

  Figure 12.  Some Common Marsh Birds


1  Anderson, W.W.   The Shrimp and the
      Shrimp Fishery of the Southern
      United States.   USDI, FWS,  BCF.
      Fishery Leaflet 589.   1966.
                           5  Odum,  E.P.  The Role of Tidal Marshes
                                in Marine Production.  The Conservationist
                                (NY), June-July.   1961.

                           6  Odum,  E.P. and Dela Crug, A.A.
                                Particulate Organic Detritus in a
                                Georgia Salt Marsh - Estuarine
                                Ecosystem,  in:  Estuaries, pp. 383-
                                388, Publ. No. 83, Am.  Assoc. Adv.
                                Sci.  Washington,  DC.    1967.

                           7  Redfield,  A. C.   The Ontogeny of a Salt
                                Marsh Estuary._in:  Estuaries,  pp.
                                108-114.  Publ. No. 83,  Am. Assoc.
                                Adv. Sci.  Washington, DC.  1967.

                           8  Stuckey, O. H. Measuring the Productivity
                                of Salt Marshes.  Maritim.es (Grad
                                School of Ocean.,  U.R.I.) Vol. 14(1):
                                9-11.  February 1970.

                           9  Williams, R.B.    Compartmental
                                Analysis of Production and Decay
                                of Juncus roemerianus.  Prog.
                                Report, Radiobiol.  Lab., Beaufort, NC,
                                Fiscal Year 1968, USDI,  BCF,  pp. 10-
   Dewey,  E. S.,  Jr.
      100 (4);115-122.
Bogs. Sci.  Am. Vol.
 October 1958.
3  Emery, K. O. and Stevenson.  Estuaries
      and Lagoons. Part n, Biological
      Aspects by J.W.  Hedgepeth, pp.  693-
      728.  in:  Treatise on Marine Ecology
      and Paleoecology.  Geol. Soc. Am.
      Mem. 67.  Washington,  DC.  1957.

4  Morgan, J.P.   Ephemeral Estuaries of the
      Deltaic Environment in:  Estuaries,
      pp.  115-120.  Publ.  No. 83, Am.
      Assoc.  Adv. Sci.  Washington, DC.  1967,
                          This outline was prepared by H. W. Jackson,
                          Chief Biologist, National Training Center,
                          Water Quality Office, EPA, Cincinnati, OH

                                WATER QUALITY CRITERIA
                                  PUBLIC WATER SUPPLIES

 A  Ideally,  public water should be available
    in ample quantity and in undefiled quality
    to satisfy all potential users, whether for
    domestic,  industrial,  recreational, or
    irrigation purposes.

 B  Realistically, nature and man's endeavors
    are not compatible with such a  goal.

    1   Climate  severely limits the  amount of
       water available in many areas.

    2   When man uses water,  he imparts
       undesirable constituents to it before
       returning it to the natural environment.

 C  In the early history of our country,  and
    even  for a good part of this century, many
    municipalities could withdraw water for
    public consumption with no treatment,
    except possibly chlorination.

 D  Today, virtually every community has a
    considerable capital investment in water
    treatment facilities.

 A The cost of treating water for public use
   is directly related to the  quality of treat-
   ment given our wastewater.

   One cycle of municipal use (as measured
   by the difference in tap water and treat-
   ment plant effluent qualities) increases
   organic  and  mineral concentrations
   substantially.  See Table 1.

 B In general,  wastewater treatment has not
   kept pace with expanding  population.

   1  The self-purifying capacity of our
      rivers and lakes has been exceeded.

   2  Many new exotic and harmful compounds,
      a product of our scientific age, are not
      removed either by waste or water
    3  As late as 1968, only 43% of our
       wastewater received secondary
       treatment.  Only 65% received any
       kind of treatment (See Tables  2 & 3

    4  As an illustration of how the burden
       has been placed on the rivers, there
       currently are still no secondary
       treatment plants on the Ohio or
       Mississippi Rivers.  This situation,
       fortunately, will end by 1975.

    5  The breakdown of the Nation's waste
       treatment facilities is given in Table 4.
       Trickling filters and stabilization
       ponds represent about half of the total
       waste treatment plants in this country.

 A  The conventional water treatment plant
    employs techniques which primarily
    clarify the water and render it hygenically
    safe.  Depending on the source,  it may
    also be necessary to:

    1  Soften the water by  adding lime and
       sodium carbonate.

    2  Employ activated carbon to improve
       taste and odor.

 B  The individual treatment units generally
    consist of a  flash mixing chamber followed
    in  sequence  by a flocculation basin,
    sedimentation tank, rapid sand filtration
    system, and a chlorine contact chamber.
    Prechlorination also is sometimes practiced.
    A typical plant is pictured schematically
    in  Figure 1.

 C  Coagulants utilized most commonly are
    alum, various iron compounds,  or lime.
    The effectiveness of the coagulation step
    is  highly dependent on  pH.   Small doses
    of  polymers will aid coagulation, but  very
    few polymers have been approved for use
    in  water treatment.
  W.Q. sto.9b. i2.7i

  Water Quality Criteria
                       TABLE 1 .-Water Quality Depreciation by One Cycle of Municipal Use
COD— unfiUnrud
COD— fillurml
COD— nilun.fl, corrected for Cl~
Aninnic drlrrKcnta (A US)
Hyilrii.vyl.-ilcil iiromntic (tmmic ncid)
C:irl)(jliyilralc3 (glucose)
Urn:inio nitrogen (N)
Nilnitft (N)
Nilrili: (N)
Ammonia (N)
Totnl nil roum (N)
Total alk.-ilinily (CftCOi)
Ciilfiiiim (On")
MiiKncflium (Mg**)
Potassium (K+)
Sodium (Na*)
Phosphate (I>0.-)
Siilfatc (SO,-)
Chloride (C1-)
Residue 105-C
Rcaiilue 600'C
Loss oil ignition
InrrrnirnUi in ma/1






IncrrmrnU in lb/dny/1,000 pupulD'.inn




                                           Water Quality Criteria
                   Table 3

               FOR YEAR  1968
Type of % of
Population Treatment Treated
43 X 106
41 X 106
28 X 106
6 X 10S
12 X 106
10 X 106
Activated sludge
Trickling filter
Stabilization pond
Raw discharge
% of

                   Table 4

               FOR YEAR 1962
14, 123



Raw discharge
Treated discharge
Primary- intermediate
Activated sludge
(21% of secondary)
Trickling filters
(38% of secondary)
Stabilization ponds
(35% of secondary)
% of




Water Quality Criteria
D  Detention times and/or hydraulic loading
   rates for the various units range as follows:

   1  Flash mix - 10 to 15 sec.

   2  Flocculation - 30 to 60 min. (longer for
      lime-soda softening).

   3  Sedimentation - 2 to  6 hours with
      preference for smaller period.
      Overflow rates vary  from 500 to 1, 500
      gal/sq. ft/day.

   4  Rapid sand filtration - 2 to 3 gal/sq. ft/
      min. with suspended solids of applied
      water no more than 10 mg/1,  preferably
      5 mg/1.

   5  Chlorination - at least 30 minute
      contact  before consumption.

E  Solids  - contact or upflow  clarifiers are
   being increasingly employed to combine
   mixing, flocculation,  and clarification
   in one  unit.  Space  is conserved and initial
   cost is usually lower.   Higher loading
   rates,  1 hr detention and 1 gal/sq ft/min
   overflow rate, are  possible but rapid
   variations  in raw water turbidity have a
   greater effect on product quality.

F  Dissolved solids and trace elements and
   compounds are little affected by the above
   conventional treatment  sequence.  We
   rely on dilution to lower the concentration
   of these elements below the toxic level.
   Calcium,  magnesium, and phosphorus can
   be removed by precipitation and iron and
   manganese by aeration but ion exchange
   and other tertiary processes are needed to
   remove most other ions.

G  Direct reuse  of wastewater is a possible
   consideration for some areas in the
   not-too-distant future.   Treatment
   requirements for direct reuse include
   secondary wastewater treatment plus
   carbon adsorption plus nitrogen removal
   plus demineralization plus breakpoint
    chlorination for destruction of viruses and
   bacterial pathogens.

 A  The Public Health Service is charged with
    setting standards for acceptable drinking
    water for the  Nation.  The latest set of
    standards  were published in 1962.  A
    revised set of standards will probably be
    forthcoming in the not-too-distant future.

 B  The Drinking  Water Standards are con-
    cerned with bacteriological quality, physical
    and chemical  characteristics, and

 C  Sampling frequency is most  critical in
    determining bacteriological  quality.
    Figure 2 indicates the minimum number
    of samples per month based on population
    served recommended by Public Health
    Service.  They range from two samples
    per month for  1, 000 people up to 500 per
    month for  10,  000, 000 people.

 D  The Public Health Service 1962 Drinking
    Water Standards are summarized in
    Table 5.

 E  In 1968, the National Technical Advisory
    Committee on Water Quality Criteria
    formally reported to the Secretary of the
    Interior on five aspects affecting water use
    in this country.  The five were recreation
    and aesthetics, public water supplies,
    fish and other  aquatic life, agricultural
    uses,  and  industrial water supplies.

 F  The Subcommittee for Public Water
    Supplies developed raw water quality
    criteria for public water supplies based
    on  reasonable  treatment effort which
    would yield saleable water meeting the
    Drinking Water Standards.

    1   Reasonable treatment is limited by the
       subcommittee to coagulation and
       flocculation with no more than 50 mg/1
       alum or iron coagulants plus alkali
       (but no  coagulant aids or  activated
       carbon), sedimentation (six hours or
       less),  rapid sand filtration (three
       gal/sq. ft/min. or less),  and chlorination
       (without regard to form or concentration
       of residual).

    2   Permissible criteria define  acceptable
       characteristics and concentrations of
       substances in raw surface waters which
       allow the production of a  water meeting
       the limits of the Public Health Service
       Drinking Water Standards without
       employing  any more than the above

                                                           Water Quality Criteria
                                Table 5


                       Drinking Water Standards

             Constituent                Recommended        Permissible
                                        Limit              Limit

A.  Bacteriological

       Requirements vary depending on number of samples
       collected per month and on type of test.

    In general:

       1.  Positive fermentation based on KPN technique

           a.  10 ml standard portions   610% positive/mo.
           b.  100 ml standard portions  £60% positive/mo.

       2.  Membrane filter              5 1/100 ml

B,  Physical

       Turbidity (Jackson units)              5
       Color (Color units platinum-
         cobalt standard)                    15
       Threshold Odor Number                  3

C.  Chemical (mg/1)

       Alkyl Benzene Sulfonate (ABS)          0.5
       Arsenic (As)                           0.01            0.05
       Barium (Ba)                                            1.0
       Cadmium (Cd)                                           O.C1
       Carbon Chloroform Extract (ccE)        0.2
       Chloride (Cl)                        250.
       Chromium (Hexavalent) (Cr  )                           0.05
       Copper (Cu)                            1.0
       Cyanide (CN)                           0.01            0.2
       Fluoride (F) - temperature dependent   0.8 - 1.7
       Iron (Fe)                              0.3
       Lead (Pb)                                              0.05
       Nitrate (NO )                         45.0
       Phenols                                0.001
       Selenium (Se)                                          0.01
       Silver (Ag)                                            0.05
       Sulfate (SO )                        250.0
       Total Dissolved Solids (TDS)         500.0
       Zinc (Zn)                              5.0

D.  Radioactive (pc/1)

       Radium - 226                           3
       Strontium - 90                        10
       Gross beta                         1,000

Water  Quality  Criteria
        Frcm surface
        infer supply
                    - Chemical stony f
                     and feeding

                                                                   Figure  1

                                                       Wash -"o'er tort
            25 tW
          Muing basin'    Flocculating       Settling basin
                                                  h fillers
                                                                                   Coagulated water
     -Post-cMorinotion far
      destruction of harmful
                                                                                         From filters
                                                                 Hbsh Hoter-^    Treated water

                                                                       Rapid sand filters
                                                                                                      Clear-water basin
                                                                                                              To high
                                                                                                            service pumps
           Filtration plant, including coagulation, settling,  filtration, poslcMorinntion and clear-water storage.  Prschlorinatton,
i.e., addition of chlorine at the mixing basin, is also common practice.
                               °  100.000
                                                            Figure 2

                                                DRINKING WATER STANDARDS,  1982

                                                         MINIMUM NUMBER OF SAMPLES PER MONW

                                                ,   «  „ u>      O               S     g

                                                                                 Water Quality Criteria
                                       Report of  the

                      National  Technical Advisory  Committee.

                               on  Water  Quality  Criteria

                         to the  Secretary of  the  Interior

                 TABLE   6.    Surface Water Criteria  for Public  Water Supplies

                                              Permlsilbla                      Dtslrabla
            Constituent or characteristic              criteria                        criteria             Paragraph

    Color  (color units)	75  	<10 	1
    Odor  					Narrative		Virtually absent 	2
    Temperature •   	do	...	Narrative  	„.	...3
    Turbidity  				do			Virtually absent	4
    Conform  organisms	-.10,000/100 ml1	.	<100/100ml'		5
    Fecal colifprms  -	2,000/100 ml1  	<20/100ml'	_	5
Inorganic chemicals:                                    (mg/i)                  (mg/i)
    Alkalinity  	Narrative 	Narrative  	6
    Ammonia		0.5 (as N)	.	-<0.01  		7
    Arsenic •  			0.05  			Absent 	8
    Barium •		1.0  		  do 		^.8
    Boron •  				1.0	.	do			9
    Cadmium •  		0.01	  do		8
    Chloride •  	250 	<25 	8
    Chromium,"  hcxavalent 		0.05	Absent 		8
    Copper '  			-.1.0		Virtually absent	8
    Dissolved oxygen 	>4 (monthly mean)	Near saturation	10
                                              >3 (individual sample)
    Fluoride *  			Narrative ..	Narrative	..11
    Hardness •		do	 do 	12
    Iron (filterable)	_		0.3  			Virtually absent 	8
    Lead •			0.05  	Absent 		8
    Manganese ' (filterable) 		_.0.05  ....	do			8
    Nitrates plus nitrites"		10 (as N)._	Virtually absent	13
    pH (range)  	6.0-8.5  	Narrative  	14
    Phosphorus" 			Narrative 	 Jo 	15
    Selenium *  		_		0.01  		-		Absent 		8
    Silver * 		0.05  	do --	8
    Sulfate «  	250	_<50 	8
    Total dissolved solids'	500	-	<200  	16
       (filterable residue).
    Uranyl ion •		5			Absent  	17
    Zinc • 			5  	-Virtually absent	8
Organic chemicals:
    Carbon chloroform  extract • (CCE)	0.15  	<0.04  		18
    Cyanide "	0.20  	.	Absent 			8
    Methylene blue active substances'	0.5	Virtually absent	19
    Oil a;id grease '	.	Virtually absent  	Absent 	20
         Aldrin •		0.017	  do 	-	21
         Chlordanc • 			0.003	  do	21
         DDT'	0.042  	  do 	21
         Dieldrin •	0.017  		  do 	21
         Endrin «		0.001  	  do 	21
         Heptachlor  • 		0.018  		  do		—.21
         Heptachlor  epoxide •  		0.018  		do		21
         Lindane »   	0.056  	   do	21
         Mclhoxychlor •	0.035	  do	21
         Organic phosphates  plus		0.1 '  			do 	21
         Toxapliene  e .		0.005  —	do		8
         2.4-0 plus 2,4,5-T.  plus 2.4,5-TP •	0.1			 do	21
    Phenols •  	0.001  		do	8
Radioactivity:                                  (pe/i>                       (oc/i)
    Gross beta •	1,000  	<100 	8
    Radium-226 • 	3  	<1 	8
    Strontium-90 •	10	_<2 	8

  • The defined treatment process  has litllo cl(«ct on this     limit may bo  relaxed if fecal Colitorm concentration do« not
constituent.                                             exceed the specified limit.
  1 Microbiological  limits are  monthly  arithmetic  averages      3 As parathion in  cholineslcrnse inhibition. It may ba necas-
based  upon an adequate number of  samples.  Votal conform     sary to  resort to  oven lower concentrations for sorna com*
                                                      pounds or mixtures. See- par. 21.

 Water.Quality Criteria
   3  Desirable criteria define characteristics
      and concentrations of a truly high quality
      surface water supply which can be pro-
      cessed with a greater safety factor by
      the above treatment to meet the Standards.

   4  Both sets of criteria are given in
      Table 6.  Where the term narrative
      appears,  the Subcommittee could not
      arrive at a single numerical value
      which would be  applicable throughout
      the country for  all conditions.

G  An examination of  the Subcommittee's
   recommendations reveals that they are
   more encompassing than the Drinking
   Water Standards.  Undoubtedly, the next
   issue of the  Drinking Water Standards will
   take cognizance of the Subcommittee's

The significance of  constituents with defined
limits in the Drinking Water Standards and
the Subcommittee's  report are discussed

A  Total Coliforms

   1  Considered reliable indicators as to
      possible presence of bacterial pathogens.

   2  In general, all coliform organisms
      exhibit similar survival and resistance

   3  Presence of any type of coliform
      in treated drinking water indicates
      inadequate treatment or excess  of
      contamination after treatment.

B  Fecal Coliforms

   1  Considered only in Subcommittee's

   2  Indigenous to intestinal tract of
      warmblooded animals.

   3  Presence indicates recent fecal

C  Physical Characteristics

   1  Turbidity, color,  and odor limits
      defined in PHS Standards.

   2  Subcommittee's Report includes above
      three plus temperature.
   3  Physical characteristics related
      to consumer acceptance rather than
      safety of the water.

   4  PHS limits are those concentrations
     'at which the physical characteristics
      become objectionable to the senses.

   5  Well operated treatment plants should
      do much better.


   1  Anionic surfactant.

   2  Above 1.5 mg/1, taste,  odor and
      foaming complaints are common. .

   3  The recommended limit of 0. 5 mg/1
      is 15, 000 times less than the sub-
      acute toxic level to rats.

E  Arsenic

   1  Cumulative effect.

   2  Absorbed into body tissues and fluids.

   3  Suspected of being carcinogenic.

F  Barium

   1  Recognized as a general muscle

   2  Capable of causing nerve block and
      transient increases in blood pressure.

   3  Acute  toxicity  associated with in-
      gestion of barium salts such as
      chloride due to irreversible changes
      in tissues.

G  Cadmium

   1  Nonessential,  nonbeneficial element
      to biological processes of man.

   2  Possesses high toxic potential.

   3  Studies have shown accumulation in
      soft tissues and marked anemia and
      retarded growth in rats and adverse
      renal arterial  damage to man.

H  Carbon Chloroform Extract

   1  Indicates man-made or natural
      organic pollutants not removed in
      water  treatment.

   2  High sensitivity.

                                                        Figure 3

                                          NITROGEN  TRANSFORMATIONS

                                                                                .' NITRATE-N
                                            / \
                                                        TIME, DAYS

Water Quality Criteria
   3  Difficult to identify exact chemical and
      lexicological nature of extracted

I  Chloride,  Sulfate and Dissolved Solids

   1  Importance associated withtaste and
      laxative properties.

   2  Laxative effect of sulfates particularly
      noticeable to newcomers and casual

   3  Experience has shown consumer shifts
      to other supplies (such as bottled water)
      when mineral concentrations become  ob-

J  Chromium

   1  Tolerance when ingested not known
      at present.

   2  When inhaled,  chromium is a known
      carcinogenic agent for man.

   3  Toxicity associated only with hexavalent

   4  Limit of Cr+6  at 0. 05 mg/1 based on
      analytical sensitivity.

K  Copper

   1  Essential in human metabolism.

   2  Does impart some taste to water
      above 1 mg/1.

   3  Large doses may result in liver

   4  Does not constitute a health hazard
      at low levels.

L  Cyanide

   1  Standard based more on toxicity to fish
      than to man.

   2   Cyanide readily detoxified to
       thiocyanate in the body.

   3   Cyanide reduced to levels of about
       0.01 mg/1 with chlorination under
       alkaline conditions.

M Fluoride

   1  Valuable oral  decay preventative in
      children at proper doses.
   2  Only harmful effect documented in
      U. S. A. is mottling of teeth at ex-
      cessive concentrations.

N  Iron and Manganese

   1  Objectionable because of astringent
      tasfee and brownish color imparted
      in excessive amounts.

   2  No health considerations.

O  Lead

   1  Acutely toxic to humans.

   2  Normal constituent in many food
      sources and cigarettes.

   3  Bacterial decomposition of organic
      matter inhibited by concentrations
      above 0. 1 mg/1.

P  Nitrate and Nitrite

   1  Nitrite can cause fatal poisoning  due to
      a condition known as methemoglobin-

   2  With infants, nitrates can result  in
      the  same situation because the low
      acidity of the infant's stomach allows
      certain bacteria to reduce nitrate
      to nitrite.

   3  The normal adult's stomach is too
      acid for this to occur.

   4  Other detrimental effects attributable
      to nitrogen compounds (including
      ammonia) are shown in Table 7.

   5  The transformation of nitrogen
      compounds when an inoculum is
      aerated for several days is indicated
      in Figure 3.  The total amount of
      nitrogen present is constant through-
      out  the transformation.

Q  Phenols

   1  Concentrations injurious to health
      far  greater than those which impart
      unpleasant taste or affect fish.

R  Selenium

   1  Produces  "alkali  disease" in cattle.

   2  Potential carcinogen to man.

                                                            Water Quality Criteria
    TABLE 7.  Importance of Nitrogen

NH  in effluents can cause DO sag in
receiving water

NH., is corrosive to copper fittings

1 NH_ requires 7 plus Cl  for breakpoint
     O                  £t

NCL causes high C19 demand
   6t              £

NH_ influences €!„  contact time

Nitrogen compounds are nutrients
NCL can be health hazard
 S  Silver
    1    Sometimes added to water for

    2    Chief effect on body is cosmetic,
        producing a blue-grey discoloration
        of eyes,  skin, and mucous membranes.

 T  Zinc

    1     Esthetic deterrent mainly due to
         acute, but transitory, gastro-
         intestinal irritation.

  U Radioactive Materials

     1    Radium-226, Strontium-90, and
         Gross beta are the three forms of
         radioactive substances  limited
         by PHS.

    2    Limits based on  recommendations
         of Federal Radiation  Council and
         approved by  the President.

 V  Additional Substances Considered by
    Subcommittee Report, but not by PHS

    1  Alkalinity

    2  Ammonia

    3  Boron

    4  Dissolved Oxygen
   5  Hardness

   6  pH

   7  Phosphorus

   8  UranylIon

   9  Oil and Grease

  10  Pesticides

  11  Herbicides


1  Fair,  G. W. and Geyer,  J.C.  Water
      Supply and Wastewater Disposal.
      John Wiley & Sons,   NY.   1954.

2  Public  Health Service Drinking Water
      Standards - 1962, PHS Publ. No.  956,
      Washington,  DC.   1962.

3  Report of the Committee on Water Quality
      Criteria, USDI, FWPCA,
      Washington,  DC.  1968.

4  Sawyer, C.N.   Chemistry for Sanitary
      Engineers.  McGraw-Hill, NY.   1960.

5  Steele, E.W.  Water Supply and
      Sewerage. McGraw-Hill, NY.  1960.
This outline was prepared by Richard C.
Brenner, Research Sanitary Engineer,
Advanced Waste Treatment Research
Laboratory, Environmental Protection
Agency,  Office of Water Programs,
Cincinnati, Ohio  45268.


A  Wastewater treatment facilities are
   engineered to recondition used water for
   beneficial reuse.  Traditionally these
   facilities are designed to achieve in a
   shorter time and  smaller space a
   similar degree of self purification that
   may occur naturally under low load
   conditions.  Current thinking stresses
   removal of many  items that are
   ineffectively removed by natural means.

B  Increasing populations and urban develop-
   ment has increased stress on water
   renovation for reuse.  Effluent and stream
   criteria are being used by State, Regional,
   and Federal Authorities for standards and
   enforcement to upgrade water resources.
   These are dynamic standards expected to
   require more treatment for more items as
   the situation requires.

C  It is technically possible to recondition
   used water for  any reuse purpose.
   Economics, public apathy, opinions,
   operational competence enthusiasm and
   enforcement commonly limit what will
   be done in a given situation.

   1  Certain items  are much more difficult
      to remove from used waters than others.
      Special procedures are  required to
      supplement conventional treatment when
      the hard-to-remove items are present
      in significant amounts.
   2  Reuse water quality requires more con-
      sideration of effluent  quality than of
      percentage removals.  It is likely to
      cost  more to upgrade treatment  from
      90 to 99% than to obtain the first 90%.
      Reuse after  90% treatment may be

D  The following schematics present an
   overview of what  may be found in a wastewater
   treatment plant and the functional purpose
   of various items.   These are not intended
   to be complete  or detailed.  Other sources
   of information provide details.

   1  It is  not possible to generalize what
      shall be included in a given plant.  The
      State agency or agencies designated for
      water quality responsibility have primary
      interest. Planning agencies.  Construction
   Grants, Professional Associations and
   other groups have responsibility in the
   use of public funds to meet the needs of
   a given situation.

2  Plant design is the responsibility of a
   professional consultant who is designated
   to select the hardware and processes
   to meet the  needs of the situation as
   defined by planning agencies.
   Information gathered from the record,
   current and projected activities of the
   contributing population, nature of  the
   wastewater  load, quality requirements
   of the receiving water, availability of
   water, site  survey,  treatment,
   experience or studies all contribute to
   design consideration.

3  The designed plant does not become a
   functional reality until construction  and
   operation has been financed with people
   competent to do the job.  "Too little-
   too-late"  is a common problem in
   treatment facilities because of losses
   in transit and/or the fact that needs
   grow faster than available facilities
   and manpower.

Options in treatment technology must be
qualified.  There are many alternate routes
for achieving a given treatment objective.
They are not equals with respect to cost
time, space, performance, operation,
opinion, etc.

1  Local opinion often favors one treatment
   option over  another that is considered
   better in terms  of cost efficiency and
   dependability by another area and  another

2  Relative cost for land, hardware,  and
   operation are a  large factor in process

3  Established practice, good or indifferent
   tends to perpetuate itself.  It is much
   less effort to "sell" a well known process
   than to design one precisely fitted to the
This outline was prepared by F.  J.  Ludzack,
Chemist, National Training Center, OWP,
EPA, Cincinnati, OH  45226.
SE.TT.eq.5a. 7. 71

Wastewater Treatment: Schematics. Functions, and Options
The following schematics and options are for orientation purposes only. They are not intended
to illustrate all possible treatment schemes or any one treatment plant. Implications of
preference are not to be assumed by inclusion, omission or order of appearance.

19 illustrations to follow

              COARSE  SCREENS
            1 TO 5 IN.  SPACING
          TO REMOVE:


                    EQUIPMENT AND OPERATIONS
                    COARSE SCREENING
                                 PRESSURE  OR  LEVEL CONTROL
               DRYING & INCINERATION

                  Wastewater Treatment: Schematics, Functions, and Options

                       GRIT REMOVAL
















 Wastewater Treatment: Schematics, Functions, and Options

            SUBMERGED DRUM



               TREATMENT                          FUNCTION

   1.  Aeration  (10-30  min. )----- a. Satisfy immediate oxygen demand
                                    b. Decrease odor
                                    c. Improve  later processing
   2. Chlorination -------------- Partial disinfection +  group 1
   3. Ozonation --------------- Decrease odor  primarily + group 1
   4. Pressurized Aeration  & Release-----Floatation of grease,  oil, solids
     May pressurize part or all of  the flow
   5. Additional Degritting during retention

                       Wastewater Treatment: Schematics,  Functions, and Options
                  PRIMARY  SEDIMENTATION
                                                   CLARIFIED  WATER
   \( Al, Fe, Co,
    \ POLYMERS )

                                CONVEYORS FOR
                                SKIMMINGS & SLUDGE
                                	SLUDGE COLLECTION  HOPPER

                           PRIMARY SEDIMENTATION


               2. RECTANGULAR TANKS

               3. CIRCULAR TANKS
                     CENTER FEED OR PERIPHERAL  FEED
                     VARIOUS WEIR ARRANGEMENTS

               4. SLUDGE COLLECTION
                     ROTATING  BRIDGE  - SUCTION OR DRAG


               6. SLUDGE DRAW-OFF
                     PISTON PUMPS
                     CENTRIFUGAL PUMPS
                     SCREW TYPE PUMPS

 Wastewater Treatment:  Schematics, Functions, and Options
                           SECONDARY TREATMENT

                        RECYCLE SLUDGE
               PARTIAL OXIDATION
                                      TO DISINFECTION
                                      ADV TREATMENT
                                    WASTE SLUDGE
                                    TO FINAL TREATMENT
                                    AND DISPOSAL
                               SEPARATION OF CLARIFIED
                               PRODUCT WATER FROM
                               SKIMMINGS OR SLUDGE
                       SECONDARY TREATMENT


     a HIGH RATE  > 1.0 Ib. COD/ Ib. MLVSS/DAY

     b CONVENTIONAL    0.4  - 1.0 Ib. COD / M LV SS/DA Y





                         Wastewater Treatment: Schematics, Functions, and Options
                       SECONDARY TREATMENT


a  HIGH   RATE    25 -  300 Ibs.  BOD5/lOOOcu.  ft.  OF  MEDIA
b  LOW  RATE      5    25 Ibs.  BOD5/1000 cu. ft. OF  MEDIA
                            SECONDARY TREATMENT
                             OXIDATION   PONDS
                 A DEPTH :  SHALLOW | 1 - 5 FT ) DEEP | 5 - 25 FT )
                 B TIME:
                       -= 3 DAYS PRIMARILY SEDIMENTATION
                       3 - 20 DAYS  SUSPENDED SLIME GROWTH
                       ^ 20 DAYS GROWTH FLOCCULATION, DEPOSITION
                         SERIES OR PARALLEL OPERATION
                             ENGINEERED OR NATURAL SOLIDS TAKEOUT

Wastewater Treatment:  Schematics, Functions,  and Options
                          WASTEWATER TREATMENT OPTIONS
                              PHYSICAL  • CHEMICAL TREATMENT

                1. APPLICATIONS
                     A. RAW WASTEWATER
                     C. AFTER BIOLOGICAL TREATMENT

                2 NATURE OF TREATMENT
                     A. LIME COAGULATION
                     B. ALUM OR IRON COAGULATION
                     C. POLYMER COAGULATION
                     D. AMMONIA  STRIPPING
                     G. ELECTROPHORESIS
                     H. ION EXCHANGE
                      I. DISTILLATION
                      J. DISINFECTION
                      K.CHEMICAL OXIDATION
                                     TREATED LIQUID STREAM
                                                                  CI   detention
chemicals clarification filtration


                                 sludge takeout
                               to receiving
                                 water or
                               other reuse
                FOR REMOVAL OF ITEMS
                PASSING  THROUGH

                 Waste-water Treatment:  Schematics,  Functions,  and Options
                     WASTEWATER TREATMENT

                       SLUDGE  DEWATERING
                                                 . 10 DRYING
                                                 & DISPOSAL

                  L HQUID RETURNED
                      TO PROCESS

                 SOLIDS CONC. 5 TO 10 TIMES
                 EXAMPLE: 4% - 25% SOLIDS
         To reduce  the  water content of the sludge as much as
         possible by the most economical and feasible route for
         the situation.

         To reduce the amount of water to be  evaporated.

                   SLUDGE  DEWATERING











Wastewater Treatment:  Schematics, Functions, and Options
                          SLUDGE DRYING & DISPOSAL
^^- 	 w OFF GASES I
X^l^\ 1

r i i
— )
£_ _
1 1 1
II 1
II 1
1 II
1 1 1
1 II
1 V-

•• .



               To complete the drying operation and convert intermediate products
               to their highest oxidation state.
               To stabilize off gases with respect to odor, oxidation state, and
               suspended solids.
                              CONDITIONING, FOR ISOLATION,
                              SANITARY FILL

                              GASES &  ASH  AT THEIR HIGHEST
                              OXIDATION  STATES





                       Wastewater Treatment:  Schematics, Functions,  and Options
                        DISPOSAL  ROUTES





                            SUBSURFACE  STRATA,  RECOVER FOR REUSE
                            WATER CONTACT

                                            Part 1

 All sewage treatment is accomplished by
 application of biological, physical, chemical
 processes.  These processes are natural
 phenomena which have been in operation since
 primeval time.   Man has not always under-
 stood these processes and in fact we may not
 have a complete understanding of them at this
 time; nevertheless, it is by means of these
 phenomena that sewage treatment is possible.

 A Specific Density

   The density of waste solids, coupled with
   the law of gravity,  provides a physical
   phenomena resulting in removal of wastes.
   Sedimentation has been observed by man
   for thousands of years and a study of
   geologic formations reveal that  sedimentation
   has been continuing for millions of years.
   In nature, the pools in streams, lakes,  and
   estuaries provide the necessary conditions
   of quiescence to allow gravity separation
   of settleable solids.

   In using the physical laws relating to
   gravity and specific density, man has
   used two processes:

   1  Sedimentation in tanks built to provide
      quiescence, and

   2  Centrifuge separation

 B Particle  Size Distribution

   Screening sewage flows to remove large
   particles is merely an application of size
   selection. Screens abound in nature as
   settled rock deposits which prevent move-
   ment of twigs, sticks, leaves and other
   solids.  The earth itself acts as a fine
   screen and filter,  removing all water-
   borne material except those that are
   dissolved.  In treatment plants, bar racks
   and sand filters are applications of these
   natural conditions.
 C  Reaeration

    Few people have failed to take the time to
    see a  waterfall or to enjoy the scenic
    beauty of a fast-flowing and turbulent
    mountain stream.  These are nature's
    examples  of reaeration facilities.  In
    addition to these dramatic aerators,
    there  is a constant exchange of molecules
    of oxygen  and other atmospheric gases
    across the liquid-gas interface of  rivers,
    lakes, ponds, and oceans.  The wind
    provides mixing energy to carry the
    dissolved  gases to portions of the  water
    mass  below  the surface.  Utilizing these
    principles as treatment processes, man
    injects air into the waste flow by use of
    air under  pressure; the making of water-
    falls by pumping the liquid into the air
    fountain-like; or,  by creating an infinitely
    large  surface area with depth being
    merely a thin film as the liquid trickles
    downward over beds of rock.

 In the  real world the aquatic community is
 very complex,  consisting of organisms of
 every  size from the virus to the fishes.
 Each has a definite role in the community
 and in a natural environment--one unaffected
 by wastes from man's activities--there is a
 very great variety of different kinds and
 species.  All are present in such  numbers as
 will maintain a balance with the food supply

 Action by bacteria in this community breaks
 down complex organic matter to simpler
 molecular forms.  These become the basic
 building blocks for new growth by other
 microorganisms. These in turn are a food
 source for yet  other, more complex,
 organisms.  This activity of decomposition
 and growth is a continuous one--such that
 the process is  cyclic.
 SE.TT.4. 1.71

Wastewater Treatment - The Result of Natural Phenomena
All the elemental components of organic
material—carbon, nitrogen,  sulfur, etc. --
are cyclic.  The carbon cycle (Figure 1) is
an example.  It can be seen that once elements
making up organic matter, from any source,
enter the aquatic environment they will con-
tinue in the cycle indefinitely unless they are
removed as a "Harvest" as fish or other

 Chemical processes in the aquatic environ-
 ment are intimately connected with biological
 activity and proceed simultaneously with
 photosynthesis,  assimilation and decomposition.

 In addition, the  chemistry of water is a
 function of the solubility and presence of
 inorganic salts in the environment.
                                        and Fats
                                      Carbon Cycle
                                        Figure 1

                                  Wastewater Treatment - The Result of Natural Phenomena
 The salt content of the oceans, the Dead Sea,
 the Salton Sea, and Great Lake are examples
 which indicate that once inorganic salts enter
 the aquatic environment they remain indefinitely
 as an integral part.   It is only by means of
 evaporation that water high in inorganic salts
 is returned,  in the form of rain and snow, to
 the fresh water state.
   A stream has capacity to accept organic
   wastes and through natural processes to
   self-purify; however, its capacity to
   assimilate wastes without seriously
   affecting water quality for other uses is
   limited by such factors as stream flow,
   reaeration rate,  temperature, etc.

A Although wastes discharged into the aquatic
    environment enter the cycle previously
    described, time is required to reach a new
   balance during which time water quality
    may be seriously impaired.  In addition,
   the new balance may not be a desirable one
   as excessive nutrients may bring about
   blooms of organisms causing nuisance
    conditions and/or foul odors  and tastes.

B  It is axiomatic that elements of wastes
    removed prior to discharge into the aquatic
    environment do not enter these cycles and
   therefore cannot  cause adverse effects.

1 Fair, G. M. and Geyer, J. C., Water
     Supply and Waste-Water Disposal,
     John Wiley & Sons, Inc.,  New York,

2 McKinney, R.E.,  Microbiology for
     Sanitary Engineers,  McGraw-Hill
     Book  Company,  New York, (1962).

3 Rich, L. G.,  Unit Processes of Sanitary
     Engineering, John Wiley & Sons,
     New York, (1963).
This outline was prepared by L. J. Nielson,
Sanitary Engineer,  Regional Program
Director,  Manpower & Training,  PNWL,
CorvaUis,  OR  97205.


A  Definitions

   1  Unit operation* ' a particular kind of a
      physical change that is repeatedly and
      frequently used as a step in the process
      for industrial chemicals and related
      materials.  Examples include filtration,
      evaporation, distillation, heat transfer,
      fluid transfer,  sedimentation and mixing.

   2  Unit process(1) a particular kind of
      chemical reaction and equipment to
      which the same basic designs and
      operation may be applied.   Oxidation,
      coagulation, disinfection,  hydrolysis
      and chemical absorption are common

   3  Process - a series  of actions or opera-
      tions conducing to an end.   A continuing
      operation or treatment consisting of a
      combination of unit  operations.   For
      example, the activated sludge process
      includes mixing, fluid and gas transfer
      and clarification among unit operations;
      oxidation,  hydrolysis and coagulation
      either biological or chemical among
      unit processes.

   4  Wastewater treatment   any process
      to which wastewater is subjected to
      remove or alter its objectionable

      a  Wastewater treatment may also be
        defined as a series of unit operations
        designed to  produce a product "clean
        water" from a raw material  "waste
        water. "

      b  Treatment is a means to renovate
        used water to meet a specific
        beneficial reuse  requirement.

      c  Conventional treatment is commonly
        classified by stage or degree of
        treatment such as preliminary or
        pretreatment, primary, secondary,
        or advanced treatment.  Processes
        such as activated sludge, trickling
        filtration or oxidation pond treat-
        ment are commonly used.  Each of
        these can be more precisely
        described and better understood
        in terms of the unit  operations
                                                       d  Unit operations for purposes of
                                                          this  outline include both "unit
                                                          operations" (A. 1) and "unit
                                                          processes" (A. 2) to distinguish
                                                          unit  process from the more
                                                          generally applied term  "process"
                                                          which may include many unit opera-
                                                          tions or unit processes.

                                                  B Increasing stress on environmental
                                                    quality means that wastewater treatment
                                                    must be  upgraded.   Upgrading treatment
                                                    means:  removal of  a larger fraction of
                                                    conventionally removed components and
                                                    removal of additional items presently not
                                                    significantly removed by conventional
                                                    treatment.  This also means  treatment
                                                    of a larger fraction  of collectable waste-
                                                    waters for a greater variety of used
                                                    water types and components for 24 hours
                                                    per day, 365 days per year.

                                                    1  The unit operation concept tends to
                                                       focus attention upon the specific com-
                                                       ponents to be removed and upon
                                                       fundamental  units most suitable for
                                                       that function. The unit operation
                                                       approach offers a wider selection for
                                                       design purposes than that  available
                                                       in empirical  plant design.   The treat-
                                                       ment  therefore may be more specific,
                                                       better tailored to the situation and show
                                                       a better cost/benefit ratio.

                                                    2  Implementation of treatment operations
                                                       requires motivated and trained man-
                                                       power.  Personnel training along the
                                                       unit operations route shortens the time
                                                       and promotes better comprehension by
                                                       focusing upon the unit  operations or
                                                       tasks most commonly used.  Rotation
                                                       among assignments is a smoother and
                                                       progression  more likely because the
                                                       individual trained in unit operations
                                                       tends to recognize familiar unit opera-
                                                       tions  in the  new assignment; his learning
                                                       requirements consist of the differences,
                                                       such as a different sequence of familiar
                                                       tasks, a smaller  number of new unit
                                                       operations,  and different handling
                                                       techniques because of  material or
                                                       situation.  Learning is split into funda-
                                                       mental  units. Personal progress,  job
                                                       satisfaction, and  competence  increase
                                                       with the recognition of proficiency of
                                                       the smaller "bits. "
PC.WAS.4b. 11.70

Unit Operations in Waste Treatment
  C This outline considers selected unit-  .,
    operations of sanitary engineering  '
    and processes based upon them.  Tables
    presented later summarize interrelations
    and the means  whereby these are combined
    into processes or stages of treatment.

    1  Unit operations are the fundamental
       "building blocks" of treatment.

    2  Unit operations are the alternate routes
       to a given objective.  Solids-liquid
       separations may be achieved by many
       different operations; some are favored
       in one situation, others limited by  that

  D The following sections consider individual
    unit operations and their characteristics
    as guidelines for selection or design.
    These  notes are general in nature and
    subject to the influence of waste  charac-
    teristics, local conditions,  practice,
    economics and water quality requirements
    of the situation.  Each unit operation is
    characterized in terms of:

    1  Favorable application factors

    2  Limiting application factors that may
       encourage selection of an alternate
       operation for a particular situation.


 The  separation of  solids from liquid, or the
 reverse,  is of primary importance  to
 wastewater treatment.  Various unit oper-
 ations or  adaptations of them to achieve this
 objective may be used to remove objectionable
 components, to protect process equipment, to
 simplify subsequent operations,  to  increase
 stability of process water, to make the water
 more amenable for treatment or to  complete
 the process. Separations may be a part of
 pretreatment, an integral process step, or
 a means of upgrading process effluents.  No
 single operation appears more frequently,  in
 more numerous  adaptations, at more stages
 in processing, and is more critical  in product
 water upgrading than solids-liquid separation.

 A  Gravity Sedimentation

    1   Favorable aspects:  This unit  operation
       is by far the least expensive and feasible
       route for a large variety of separations.
       May be adapted for separation of a  variety
       of materials having a specific gravity
       sufficiently different from that of water
       and  immiscible in it such  as:  High
       density sand, gravel or scale, moderate
       density organic suspended materials,
       low  density floatable materials.
      Requires simple and generally available
      equipment.  Operating variables are
      known and generally controllable to
      favor reliable treatment.

   2  Limitations:  Adversely affected by
      variations in wastewater characteristics
      and flow.  Requires a moderately large
      capital,  equipment and area investment.
      Sludge detention conducive to solids
      liquefaction and feedback.  Affected by
      short circuiting, turbulence, distribu-
      tion, temperature or density changes.
      Relatively slow operation in most

B  Surface Filtration

   1  Coarse or fine screens

      a Favorable: Inexpensive simple
        operation and equipment.  Reliable
        removal of discrete solids larger
        than the screen openings.  Equipment
        available  and operating practice known.
        Simplifies subsequent operations.  Low
        area requirement.

      b Limitations:  Susceptible to  plugging,
        large quantities of wet,  difficult-to-
        handle solids.  Variable loading may
        result in operating and performance
        problems associated with higher loads.

   2  Microscreens

      a Favorable: Produces  an effluent of
        low suspended solids (<10 mg/1) and
        low turbidity (2JTU) at low capital,
        operating time and area cost at
        rated loading.  Simple  operating
        requirements.  Equipment avail-
        ability good.

      b Limitations: Poor tolerance for high
        suspended solids feeds (>50  mg/1).
        Tends to plug filter surface.  Affected
        by changes in waste characteristics.
        Solids breakthrough at  excessive

   3  Diatomaceous earth filtration

      a Favorable:  Produces a high quality
        effluent low in suspended solids and
        turbidity (0. 1 to 1. 0 JTU).   Low area
        requirement.  Pressure buildup
        rather than solids breakthrough warn-
        ing of overloads.

                                                          Unit Operations in Waste Treatment
      b   Limitations:  High pressure drop
         through the filter; rapidly increases
         with solids loading.  Tends to plug.
         Low output/ sq. ft. / unit time with
         high suspended  solids feed.

   4  Vacuum filtration

      a   Favorable: Suitable for treatment
         of a variety of solids-liquid
         concentrates.  Large  choice of
         filter media including string,  coil,
         cloth (natural or synthetic) screens.
         Versatile in adaptability for varying
         conditions and loading.  Low area
         requirement.  High capacity per
         unit area.

      b   Limitations:  Complex operation,
         high maintenance cost.  Usually
         requires chemical coagulation or
         coagulant aids.   High  capital and
         operating cost.   Requires frequent
         attention to maintain capacity during
         varying load and sludge characteristics.
         High cake  moisture content produces
         a poor quality filtrate.

C  Bed Filtration

   Many options are available such as type
   of media (sand,  coal,  gravel, synthetics,
   etc. ) size of media (from fine sand to
   rock  or  manufactured media) and flow
   direction (up flow or down flow, com-
   pressed or expanded bed).   Fine media
   and downflow operation may resemble
   operational characteristics  of surface
   filtration.  Coarse media,  multi media,
   expanded beds represent filtration in
   depth.  In some  situations such as trickling
   filtration, the process is largely a
   biological phenomena  rather than intrinsi-
   cally filtration.

   1  Sand  or single media filtration.
      Characterized by a high rate of head
      loss development with high solids

      a   Favorable: High quality effluents
         produced.   Increased  solids,  oxygen
         demand, and organism removals
         specially with low application  rates.
         Beneficial for upgrading reasonably
         good quality treated effluents.
         Dependable polishing step.  Simple
         operational control.

      b   Limitations:  Large area requirement.
         Usually requires pretreatment for
         removal of most of the solids.  High
         head loss development specially for
      high rate application.  Usually
      an intermittent operation.  Low
      capacity per unit time.  Media
      replacement based upon incidence
      of "balling," backwash losses,
      deposition on the grains, and
      nature of feed stock contamination.
      Possible  odor development.
      Backwash water may be volumi-
      nous  and generally requires

2  Soil percolation

   a  Favorable:  Generally a dependable
      method of effluent disposal where
      land is available.   Returns both
      water and wastewater nutrients to
      the food chain.  Useful for land
      reclaimation purposes.  Requires
      simple operation and low operational
      cost.  Versatile for use with a wide
      variety of wastewater types.

   b  Limitations:  Commonly limited with
      respect to application rates.   Requires
      a  large land area for intermittent
      operation.  Capital cost primarily
      related to land area requirements.
      Disinfection commonly required.
      Good agricultural practice needed
      to support good engineering.   A
      cover crop, tilling and drainage
      control generally required.  Subject
      to seasonal, soil, and topographical
      factors.   Odors and health hazards
      tend to produce a poor public image.
      Ground or surface  water hazard

3  Multi media filtration

   The use of two or more filter media
   in which both size and density are
   variable makes it possible to distribute
   trapped  particulates in a wide zone
   with  respect to filter depth.  Usually
   a larger sized lower density media
   are placed over a fine high density
   media.  Larger particulates are
   trapped  in the  upper zone while the
   fine media upgrade effluent clarity.
   Head loss development occurs more
   gradually to permit longer runs of high
   product  quality as compared with
   single media filtration.

   a  Favorable:  Head loss distributed
      throughout the bed, builds up more
      slowly to permit higher rate and
      volume application.  Dependable
      high quality effluent production.
      Generally high capacity characteristics.

Unit Operations in Waste Treatment
         Capable of being tailored to fit a
         particular feed and effluent quality

      b  Limitations:  Design generally
         requires more careful evaluation
         of feed and product quality
         requirements.  Solids load and
         nature are critical.  Requires
         more careful control during back-
         washing to make it a more complex
         operation than sand filtration.
         Intermittent  operation.  Media and
         equipment more expensive.  Usually
         requires pretreatment,  Backwash
         water requires retreatment--may
         require  more backwash water or
         more time than for single media
         filtration.  Media replacement may
         be higher.

D  Pressure Floatation

   1  The operation consists of aeration
      of part or all of the liquid flow in a
      covered tank to trap exhaust  air and
      provide a controlled pressure rise.
      Under pressure more gas will dissolve
      than can be retained at normal pressures.
      Discharge of the pressurized liquid to
      the clarifying compartment permits
      release of excess dissolved gas.  The
      released gas tends to associate with
      oil, scum  and particulates to favor
      separation from water as  a floatable
      concentrate.  Variables include time
      pressure,  turbulence,  air-liquid-solid
      interface area and nature,  and associa-
      tion tendencies  in both pressure and
      clarifying compartments.

      a  Favorable

         The floatation process  is highly
         versatile for separation of oils
         emulsions or particulates.  It may
         be used for thickening or clarifica-
         tion with or without conditioning
         chemicals such as surface active
         materials, coagulants or other
         separation aids.   It is possible to
         employ higher loading and higher
         overflow rates than for sedimentation.
        A higher solids concentration factor
         may be achieved.  More complete
         clarification of hard-to-separate
         materials is  possible.  Usually
         requires less area per unit of

         1) Activated sludge concentration
           by floatation is becoming
           increasingly popular because the
           hydrated solids are amenable to
           the floatation process to a greater
           extent than for sedimentation.

         2) Oil and surface active agents
           tend to be more completely
           separated by floatation to pro-
           duce a better clarified product

      b  Limitations:  Usually requires very
         careful design and operation for a
         specific situation.  The complex
         operation is sensitive to feed stock
         variations.  Generally more com-
         plex equipment requiring closer
         control.  More amenable to moder-
         ately concentrated feeds.  Thickening
         operations may require duplicate
         solids handling for removal of float-
         able and settleable fractions.  The
         subnatant zone commonly has a high
         solids concentration  requiring
         retreatment.  Clarification commonly
         is improved by increasing feed stock
         concentration.  More expensive in
         capital and operating cost than

E  Centrifugation

   The centrifuge has a long history for
   dependable separation of liquid-solid
   suspensions according to specific gravity
   differences.  Solid bowl, basket, or disc
   type machines are available.  Horizontal
   solid bowl units appear to have the greatest
   potential in sanitary engineering.  Organic
   sludge from water and grit from  organic
   sludge separations are attractive.
   Variables  include feed rate,  solids-liquid
   characteristics, feed concentration,
   temperature, chemical additives; machine
   variables include bowl design, rotational
   speed, contained volume,  input,  distribution
   and takeout mechanisms.

   1  Favorable: Highly versatile; may be
      designed for high sludge concentration
      or  high separation on a  variety of feeds.
      High  capacity-low area  requirements.
      Low capital cost per unit of capacity.
      Capable of solids concentrations up to
      30  to 35 percent with favorable loads
      and operation; continuous performance.

   2  Limitations: High power requirements
      (~0. 5 HP/gpm).   Usually necessary to
      make a choice between high solids con-
      centration and high solids recovery--
      unlikely to have both. Reduced feed

                                                       Unit Operations in Waste Treatment
       concentration tends to reduce both con-
       centration and recovery of centrifuged
       solids.  Centrate generally requires
       retreatment. Requires suitable design
       for a particular function,  material and
       flow and performs best at rated loading.

 For purposes of this outline a chemical unit
 operation refers to a particular kind of chem-
 ical transformation of feed stock (I.e. ).   The
 transformations may be inseparably associated
 with both physical and biological changes, for
 example, hydrolysis,  oxidation and disinfection
 are closely related to biological changes,
 while coagulation, flocculation are closely
 related to physical operations.  These trans-
 formations may be natural in origin  or induced
 by chemical additions.  In a multicomponent
 wastewater the control of treatment  largely
 is a compromise situation among operations
 of biological-chemical-physical natures,  some
 favoring, some interfering, with the intended

 A  Neutralization

    The combination of excess acids and
    alkaline materials to form a salt and
    water is a recurrent natural process
    called Neutralization.  Among other
    components, organisms release both
    carbon dioxide (acidic) and ammonia
    (alkaline) which neutralize each other to
    form ammonium bicarbonate and water.
    Under certain conditions nature tends to
    inhibit itself where an excess of acid or
    alkaline materials are favored such as in
    low pH deep waters or high pH surface
    waters.  Growth may become limited
    because of pressure retention of excess
    CO2 or rapid assimilation of CO
    respectively.  This unbalance is unlikely
    to be as serious as that due to local dis-
    charge of acid or alkali released from
    manmade sources.  Neutralization is a
    common requirement.

    1  Favorable:  Neutralization enhances the
       probability for biological and certain
       chemical transformations.  Commonly
       reduces corrosivity of acid waters.
      Increases acceptability of acid or
      alkaline waters for beneficial reuse
      in water supply, recreation, wildlife,
      agricultural industry and esthetics.

   2  Limitations:  Generally high operating
      and control cost.  May produce gross
      quantities of solids for disposal or
      increase the dissolved solids in the
      water.  Requires close control to
      prevent excessive additions.

B  Oxidation

   The oxidation of organic  waste components
   in water is a primary consideration in
   wastewater stabilization.  This process is
   intimately linked with solids-liquid sep-
   aration.  For example, organic soluble
   compounds may be oxidized biochemically
   to form settleable  agglomerates of cell
   mass, to removable gaseous CO9 and to
   less reactable water.  Nitrogen compounds
   may be converted to the oxidized state and
   reduced to less reactable and removable
   nitrogen gas.

   1  The use of oxygen (aeration or surface
      oxygenation) from air is by far the most
      used unit operation for supplying
      essential oxygen for intermediate and
      terminal stabilization.

      a   Favorable:  Generally available, low
         cost.  Necessary pumping,  cleaning
         and transfer equipment available at
         reasonable cost.  Moderate power
         cost.  Transfer capability reasonably
         good.  Dependable  supply.

      b   Limitations:  Limited solubility of
         oxygen in contact with air.  Large
         capital investment in tankage and
         space.  Air solubility and transfer
         limitations generally mean a low to
         moderate rate process.

   2  The use of commercial oxygen instead
      of air permits a five-fold increase in
      oxygen  partial pressures.

      a   Favorable:  Higher oxygen partial
         pressures permit higher solubility
         of oxygen in water and greater

Unit Operations in Waste Treatment
        oxygen transfer rate in high demand
        situations.  More likely to maintain
        a higher residual DO in high rate
        situations, or through the clarifier
        stage.  More complete stabilization
        possible in less tankage and/or time.
        High oxygen  tension favors  sludge
        oxidation--lowers solids accumulation.

      b  Limitations: Better design require-
        ments necessary to maintain high
        oxygen use efficiency.  More complex
        system,  more costly.  Covered
        tanks and oxygen production facilities
        nearby usually required to favor
        cost/benefit  ratios.  Requires better
        operational control.

      Ozone is another form of oxygen used
      primarily for special purposes.

      a  Favorable: Ozone is used primarily
        for odor control because of its high
        oxidizing energy and high activity in
        water.  Capable of reacting with
        components that may not react with
        oxygen under similar conditions.

      b  Limitations:  Ozone (O.) is a highly
        unstable compound.   Generally
        cannot be stored or made in high
        concentrations.   Usually requires
        formation on site  and use in pre-
        treated water.  High unit cost.
        Complex control.

      Chlorine is commonly considered for
      disinfection; disinfecting properties
      are inherently associated with oxidizing

      a  Favorable:  Commercially available
        chemical,  control equipment available,
        operating controls generally known.
        High energy material.  Relatively
        simple operation.  Versatile material
        capable of use in a variety of situations.
        Cost higher than that for oxygen but
        has a greater reactivity for many
        beneficial operations.   Rapid reaction
        in most situations.
      b  Limitations: Hazardous-nonspecific
         toxicity in air or water.  Chlorine
         reaction produces HC1 during
         reaction.  Usually requires neutral-
         ization.  Highly corrosive in water
         solution or wet gas.  Certain com-
         ponents such as ammonia prefer-
         entially react with chlorine to cause
         high chlorine demands.  Requires
         close control.  Generally requires
         pretreatment to avoid excessive
         chlorine dosage.

   5  Peroxy-acid oxidizing agents

      Permanganate and dichromate are the
      most common peroxy-acids used in
      sanitary engineering. Permanganate
      is relatively pH independent,  dichromate
      is an effective oxidant only under acid
      conditions.  Both have high oxidizing
      energy for special purposes.

      a  Favorable: High oxidizing energy.
         Capable  of being separated from
         product water.  Adaptable for  special
         requirements such as destruction of
         most organic materials or color.
         Permanganate may occur naturally
         in water and in excess its color is
         its own indicator.

      b  Relatively high cost per unit of
         oxidizing energy.  Excess reagent
         contributes to poor quality water.
         Close control required.  Commonly
         does not oxidize ammonia nitrogen.
         May require catalysis to reduce
         delayed reactions.

C  Hydrolysis

   The addition of water to split large
   molecules into two or more simpler
   substances is an inevitable part of
   biodegradation.  Cell  mass may be
   hydrolyzed to form smaller component
   parts  that are partially oxidized to yield
   energy for building another crop of cells.
   The process will continue as long as
   oxidation energy is sufficient for growth.
   Treatment tends to produce a low energy

                                                        Unit Operations in Waste Treatment
    discharged effluent in which hydrolysis
    and oxidation become lower rate operations •

    1  Favorable:  Items favoring hydrolytic
       cleavage (liquefaction) include high or
       low pH, hydrolase enzymes or other
       catalysts, high temperatures, low or
       negative oxidation reduction potential
       (low oxygen tension) or anything favoring
       introduction of water into a complex

    2  Limitations: Any situation favoring
       resynthesis of hydrolyzed components
       into larger molecules reduces the net
       effect of hydrolysis. Algal photo-
       synthesis,  bacterial or plant growth,
       absence of toxic components, and
       favorable conditions for growth usually
       are associated with high rate hydrolysis
       in a high energy situation but growth
       may be the predominant reaction.
       Any situation favoring  dehydration
       limits  hydrolysis.
 Isolation and stabilization are the key factors
 in wastewater treatment. Unstable inter-
 mediates  must be stabilized to be acceptable
 as gaseous or solid residues.  Isolation refers
 to separation of gaseous and solids residues
 from the recombining media—water.  It is
 not possible to isolate or to stabilize to "end"
 products — somewhere in time recycle will
 occur.  Each treatment operation is intended
 to hasten  recycle for beneficial use and delay
 other types of recycle.

 A Table  1 summarizes the  functions of
    various stages of treatment.  Certain
    unit operations are repeated at each
    stage in a different manner.
                TABLE 1


Preliminary or Pretreatment;

1.  Removal of roots,  rocks, rags

2.  Removal of sand,  grit, gravel

3.  To "freshen" the wastewater by short
    term aeration, chlorination, grinding
    or otherwise protect and promote sub-
    sequent treatment

Primary Treatment

Removal of readily settleable or floatable

Secondary  Treatment

Conversion of soluble or colloidal components
to removable form with partial stabilization
in process (commonly biodegradation).

Advanced Treatment of Wastewaters

Biological  chemical or physical treatment
of used water to meet specific reuse quality
requirements.  May consist of general or
specific item clean-up.

Solids Disposal

Nonpollutional takeout favoring conversion
to stable residues and separation of gas,
liquid, and solid phases.
                                              B Tables 2 and 3 list selected unit operations
                                                 and the  stages or processes in which they
                                                 may be  used.  Note that many of these
                                                 may occur repeatedly and that there is the
                                                 possibility of including one or more
                                                 options  in any given treatment process

Unit Operations in Waste Treatment
   depending upon performance requirements
   and nature of the problem. These lists of
   physical (2) and chemical (3) operations
   are not complete.   It is not likely that all
   of those listed may be included in any
   modification of a treatment facility.  The
   problem is to select a series of operations
   suitable to meet the performance require-
   ments  of the situation at a favorable  cost/
   benefit ratio.
             C  Several processes are possible for
                secondary treatment.  Each of these have
                several modifications.  The most common
                are based upon biological-physical unit
                operations.  Chemical-physical operations
                may be used to upgrade the overall
                removal,  or to remove specific components
                commonly not sufficiently removed by
                treatment.  The same processes may be
                used for advanced treatment providing the
                degree of removal is upgraded on all
                components of interest to meet specific
                reuse  requirements.
                                         TABLE 2

Unit Operation
Fluid Transfer
   liquid pumping
   sludge pumping
   process residues-scum
Gas Transfer
   into process-oxygenation
Solids Transfer
   applied chemicals
   process residues
Heat Transfer
Solids-Liquid Separation
   coarse screening
   gravity sedimentation





          Stage or Process*

      Sec   Adv   AS   TF


























                                                      Unit Operations in Waste Treatment
                                        TABLE 3

                             CHEMICAL TRANSFORMATIONS
Unit Operation
                                  Pre   Pri
     Stage or Process*
Sec   Adv   AS    TF
*Coding Tables 1 and 2

Pre - Preliminary or pretreatment stage

Pri -  Primary clarification stage

Sec -  Secondary treatment stage

Adv - Advanced treatment stage

AS - Activated sludge treatment process

TF - Trickling filtration treatment process

OP - Oxidation pond treatment process

SP - Sludge processing stage

D - Disposal stage (solids)
SP    D
Oxidation Reduction
wet combustion
dry combustion
bleaching (color removal)
Hydrolysis (liquefaction)
Solids-Liquid Separation
ion exchange
electrodialysis (phy-chem)
assimilation (biol-chem)
absorption (phy-chem)



































Unit Operations in Waste Treatment
   1  Activated sludge

      This process is based upon a mixed
      fluid suspension of solids concentrates
      from previous operations and raw
      wastewater in the presence of excess
      oxygen to rapidly stabilize the incoming
      pollutants by biological growth, trans-
      fer to the solids phase, agglomeration
      and solids liquid separation.

      a Favorable:  Versatile process
        capable of being adapted to high
        performance on most types of
        organic contaminants.  Generally
        capable of high efficiency in stabi-
        lization and clarification.  Lower
        tankage and area requirements than
        for most biological processes.
        May be modified to achieve high
        removal of nitrogen phosphorus and
        solids.  Adaptable to a.wide  range in
        removal efficiency.

      b Limitations: Requires close control
        of load ratios and operating  conditions.
        High oxygen requirements.  Subject
        to upset by qualitative and quantitative
        shock loads.  Unmodified process
        commonly shows poor removal of
        nitrogen and phosphorus.  Subject to
        the variations of characteristic of
        biological treatment. High operating

   2   Trickling filtration

      Employs an attached  media of sewage
      slimes on the support surface for transfer
      and  stabilization of organic pollutants in
      the influent.

      a Favorable:  Versatile process capable
        of being adapted for  intermediate
        performance on most types of organic
        waste.  Low operating cost.  Adaptable
        for a fairly wide range of removal on
        substances showing good solids trans-
        fer efficiency.

      b Limitations:  High capital cost for
        land and tankage (rock or slag).
        High pumping cost on manufactured
        media.  Generally not amenable for
      coagulation and clarification.  Fewer
      operating controls possible.
      Subject to the variations character-
      istic of biological treatment even
      though it may not be as noticeable
      due to generally turbid effluents.

3  Oxidation ponds

   Employs natural purification phenomena
   of sedimentation, aerobic and anaerobic
   degradation, algal photosynthesis
   usually in a sacrificial pond or series
   of ponds.

   a  Favorable:  Capable of high treat-
      ment efficiencies with low operational
      cost.  Adaptable to low or high
      removal efficiencies depending on
      land and capacity or time availability.
      Useful on a wide variety of waste-
      waters.  Land is available for
      upgrading treatment and other uses
      as needed.

   b  Limitations:  Generally limited to
      application where land costs are
      low. Subject to poor performance
      during ice cover, overloads,  spring
      warmup and unexpected boil-up.
      May be an odor nuisance at times.
      Generally a low rate process with
      poor solids recovery characteristics.
      Appears to have a tendency to poorer
      performance after several years of

4  Physical chemical treatment  operations

   Physical chemical treatment by  lime
   precipitation and activated carbon
   adsorption is becoming recognized to
   an increasing degree.

   a  Favorable:  Is a versatile process
      capable of being adapted to very
      high degrees of treatment on  a
      variety of wastewaters.  Recovery
      of added lime and regeneration of
      spent carbon by controlled incin-
      eration permits chemical reuse and
      reduces  solids disposal.  Relatively
      low capital costs and space require-
      ments .  Capable of application over

                                                          Unit Operations in Waste Treatment
        wide flow variations with dosage
        and regeneration time control.
        Freedom from toxic effects.

      b Limitations:  Generally higher
        operating cost.  More complex
        process requires precise operational
        control.  May require pretreatment.
        Chemical reuse almost mandatory to
        limit solids disposal requirements.
        Operating history for wastewater
        applications scant.

D  Sludge Processing or Disposal Routes

   1  Wet combustion by aerobic biological

      Activated sludge, trickling filtration
      and oxidation ponds involve a certain
      amount of processing and disposal of
      solids to a degree limited by the amount
      of carbon dioxide and water formed in
      process.  Aerobic sludge digestion
      accentuates solids disposal.

      a Favorable:  Generally a conventional
        bio-chemical  process using estab-
        lished procedures.  Time, oxygen
        supply and favorable conditions are
        basic requirements.  Versatile for
        a variety of wastes.  Generally
        capable of a high degree of stabilization,

      b Limitations:  Process  limited to a
        residue solids level containing about
        40% volatile content  (10 to 20% of the
        feed volatile solids).  High liquid
        recycle of N,  P, and solids content.
        Generally a long term  operation.
        Process interference serious for low
        temperatures, toxic agents,  or
        unfavorable pH. Generally produces
        a low concentration sludge (\ 2%).

   2  Wet combustion--elevated temperature
      and pressure

      Wet combustion of organic wastes at
      various pressures in enclosed vessels
      with liquid temperatures of 350°F  or
      above  have been  effective for  separation
      of a highly stable mineralized ash.
   a  Favorable:  Capable of producing
      an easily separated high-mineral
      ash.  Rapid process low area
      requirements, low solids  disposal

   b  Limitations:  Requires complex
      equipment and high heat require-
      ments.  Good control essential.
      Residual liquid has a high color and
      contaminant level.

3  Anaerobic digestion

   This process is both a sludge con-
   ditioning and a solids separation
   process.  Sludge residuals after
   digestion are more  concentrated in
   solids content and decreased in volume
   and mass due to escape of methane and
   carbon dioxide gas or elutriate.

   a  Favorable:  Versatile and dependable
      process of organic stabilization for
      suitable loading, mixing and tem-
      peratures.  Low cost operation.
      Produces a usable product gas.
      Residual solids relatively stable,
      improved in concentration, and

   b  Limitations:  Capital costs relatively
      high for space and tankage.
      Susceptible to shock loading,  tem-
      perature changes, poor  mixing or
      toxicity.  Once upset--it requires
      appreciable time and effort to
      restore  good performance. Recycle
      liquids are high in dissolved and
      suspended solids; are difficult to

4  Drying and incineration

   Many modes of drying such as drying
   beds, land  spreading, flash drying are
   possible with wet sludge.  Incineration
   in a fluidized bed, rotary kiln or
   multiple hearth are used.  The multiple
   hearth is one example of drying and

   a  Favorable: Dependable, versatile
      operation for thick sludges where

Unit Operations in Waste Treatment
        heat release is close to heat require-
        ments for water evaporation and
        temperature rise.  Can be controlled
        to produce clean stack gases and
        stable mineral solids residue.   Rapid
        process.  Low area requirements.
        Control techniques well established.

     b  Limitations: Solids feed of low  heat
        and high water content may require
        excessive auxiliary fuel cost.
        Generally requires stack gas
        reburning and solids recovery to
        meet air quality requirements.
        Generally costs about $50 plus per
        ton of dry solids for operation.
        Requires close control of feed,
        burner temperature and other
        operating variables.

   5 Wet disposal of sludge

     Application of wet sludge to spoil areas,
     stripped terrain, farm or marginal
     land has been common practice for a
     long time.  Piping instead of truck
     hauling is receiving increased con-
     sideration to extend the disposal area.

     a  Favorable:  Costs of disposal may
        be reduced by avoiding costly drying
        operations.   Pumping of wet sludge
        is more economical than hauling.
        Possibilities for use of the organic
        and water for reclamation of waste
        land is attractive as a means of
        recycling the wastes into the food
        chain. Isolation possibilities are
        improved by remote application
        from population centers.
      b  Limitations: Good engineering and
         farming practice are required.
         The local residents do not appreciate
         receiving waste materials from
         elsewhere unless practice and
         public relations are top rate.
         Possible hazards from surface
         ground water and air pollution dim
         the good neighbor policy.


This outline contains appreciable material
from a previous outline by F.  P.  Nixon.


1  Rose, Arthur and Elizabeth.  Condensed
      Chemical  Dictionary,  7th Edition.
      Reinhold Publishing Corporation.
      New York.  1961.

      Glossary,  Water and Wastewater
      Control Engineering.   1969.

3  Rich, Linvil G.   Units Operations in
      Sanitary Engineering.   Wiley.   1961.

4  Rich, Linvil G.   Unit Processes of
      Sanitary Engineering.   Wiley.   1963.
This outline was prepared by F. J. Ludzack,
Chemist, National Training Center,
DTTB,  MDS,  OWP. EPA,  Cincinnati,
OH  45268.


 A Nature of Hazards

   1  The hazards to which wastewater
      treatment plant or wastewater pumping
      station operators may be subjected in
      the course of their work, include
      exposure to:

      a  Physical injuries

      b  Body infections

      c  Noxious gases and vapors

      d  Oxygen deficiency

   2  Hazards are real and preventive steps
      are necessary if serious damage to life
      and property are to be avoided.

 B Prevention of Accidents

   1  Occupational hazards can be avoided by:

      a  Proper design of wastewater pumping
         stations and treatment plants

      b  Use of safety  equipment

      c  Efficient administration and the
         execution of safe practices.

 A Treatment Plant Design

   1  There are many danger spots around
      wastewater treatment plant structures
      at which fencing,  chaining, railings and
      guards are needed to safeguard
      operators from physical injuries.

   2  Good judgment and operating experience
      are needed for the recommendation of
      adequate fencing and railing protection.

   3  Machinery should have guards for belts,
      gears,  and all exposed moving machine
      parts.  Adequate space  should be
      provided for machinery to facilitate safe
      repair and maintenance.
   4  All electrical equipment and wiring
     should be properly insulated and
     grounded.  Suitable rubber mats
     placed before switchboards should be

   5  Space should be provided for stairs and
     handrails rather than ladders.

   6  Many treatment plants are attended,
     particularly at night,  by only one
     operator, whose safety deserves
     special consideration.  Adequate  day
     and night lighting for  the grounds and
     buildings is a necessity.

   7  Plants using chemicals for treatment
     of sewage or sludge should be provided
     with an ample supply  of potable water
     for washing off chemical splashes or
     spills on the body.

   8  Fireproof buildings,  including
     sprinkler equipment are desirable.
     Fireproofing is especially important
     where large quantities of chlorine are

B  Safety Equipment

   1  Warning  signs are needed near
     dangerous machinery, blind obstacles
     and for any  hazardous location where
     stumbling may occur.

   2  Fire extinguishers of an approved
     design should be placed in sufficient
     number around the plant,

   3  For entering deep tanks, and other
     deep underground structures,  the
     wearing of a harness  leather safety
     belt should be mandatory, and at  least
     two men  should be on guard at the
     surface at all times that workers are
     in these structures.

   4  There are times when a life preserver
     and throw-line on a settling tank  rail
     may prove  its worth.   Drowning is a
     mishap that should not occur.

  Wastewater Treatment Plant Safety Practices
  C Safe Practices

    1  Structures and appurtenances of treat-
       ment plants should be kept in good
       repair and maintained in a tidy condition.
       Tools should be picked up, manhole
       covers  promptly replaced, and every
       effort made to promote good housekeeping.

    2  Walkways should be kept free of grease,
       oil and  ice.

    3  Safe procedures should be mandatory
       for electrical maintenance.

    4  Hazardous assignments should not be
       undertaken without adequate  personnel.

    5  Accident-preventive instruction of
       permanently legible character should
       be prominently posted by management.

 A  Treatment Plant Design

    1  Clean and well equipped washrooms
       should be provided.

    2  Water foot-valves should be provided
       on potable water supplies.  Their use
       will prevent contamination of plumbing
       fixtures and reduce the probabilities of
       reinfection while eating or smoking.

    3  Clean dressing rooms equipped with
       benches, mirror, and metal lockers
       should be provided the workers for
       changing to and from work clothes.

    4  Plants should have well lighted and
       equipped lunchrooms where workers
       can prepare food and eat in clean

    5  Swing doors (with glass  ports) are
       desirable for use in laboratories,
       washrooms and locker rooms.

    6  Cross connections between drinking-
       water supply and sewage or sludge
       piping or equipment should be strictly
       forbidden and continuous diligence
       exercised during construction and
       operation to avoid them.

    7  All bronze double check valves should
       be installed on the water main leading
       to sewage treatment plants.  The
       installation should allow for ready
       checking of the valves for leakage.
       The water service pipe for plant
       drinking water should be taken off the
       supply main just ahead of the double
       check valves as an additional safeguard
       to the employees.

 B Safety  Equipment

    1  Emergency first-aid kits  should be
       available for treating minor cuts,
       burns and wounds.

    2  A 2  per cent tincture of iodine solution
       is recommended for immediate use on
       minor cuts  or wounds.

    3  Rubber gloves should be worn to
       prevent infection while cleaning clogged
       sludge pumps, handling screenings,
       sewage,  grit or other filth.

    4  Coveralls or a complete change to
       work clothes is recommended during
       working hours.

 C Safe Practices

    1  A physician should treat all  but minor

    2  Personal cleanliness should be
       emphasized and direct contact with
       sewage wastes should be discouraged.

    3  Periodic inoculations against typhoid,
       para-typhoid and tetanus should be
       made available to personnel.


 A Location of Hazards

                                                   Wastewater Treatment Plant Safety Practices
   1  In  enclosed sewage screening comminutor
      rooms where outfall sewers discharge

   2  In  covered tanks where organic matter
      is  decomposing, such as separate sludge
      digestion tanks, septic tanks,  sludge
      storage tanks,  sludge conditioning tanks,
      or sewage screening bins

   3  In  digestion tank galleries or rooms
      where sludge gas piping,  gas boilers,
      and gas appurtenances are located

   4  In  sludge gas storage  tanks

B  Types of Gases

   1  Dangerous gases which may be
      encountered occasionally are:

      a  Ammonia (NH )
  b Sulfur dioxide (SO )

  c Phosphine (PH  )

  d Ethane (C,,HJ
                2  o

  e Industrial waste gases:  such as
     carbon bisulphide, carbon tetra-
     chloride and methyl  chloride

2 Chlorine handling  facilities.
  Chlorinators should be located in a
  room which can be heated and has
  ample ventilation.  The room should
  be fireproof and equipped with
  automatic  sprinklers.

3 Equipment for the detection of various
  gases and  oxygen deficiency is shown
  in Table 1:
                                            TABLE 1

                                      SAFETY EQUIPMENT

                    Gas or Vapor                          Equipment for Detection

               Hydrogen Sulphide	    1.  Lead acetate impregnated paper (qualitative)
                                               2.  Hydrogen sulphide detector (quantitative)

               Methane	    1.  Combustible gas indicator or explosimeter
                                               2.  Oxygen-deficiency indicator

               Carbon Dioxide.	       Oxygen-deficiency indicator

               Nitrogen	       Oxygen-deficiency indicator

               Oxygen Depletion	       Oxygen-deficiency indicator

               Carbon Monoxide 	    1.  Carbon monoxide indicator
                                               2.  Carbon monoxide detector set
                                               3.  Carbon monoxide ampoules

               Hydrogen	    1.  Combustible gas indicator or oxplosimeter
                                               2.  Oxygen-deficiency indicator

               Gasoline	    1.  Combustible gas indicator or explosimeter
                                               2.  Oxygen-deficiency indicator for
                                                  concentrations over 0.3%

               Sludge Digestion Tank Gas	    1.  Combustible gas indicator or explosimeter
                                               2.  Oxygen-deficiency indicator

               Chlorine	    1.  Aqueous ammonia
                                               2.  Odor

               Ammonia	       Odor

               Sulphur Dioxide	       Odor

               Ethane	    1.  Combustible gas indicator or explosimeter
                                               2.  Oxygen-deficiency indicator

 Wastewater Treatment Plant Safety Practices
 C Safety Equipment

   1  The following safety equipment for the
      plant should be included in the

      a Safety harness and recovery line

      b First-aid kit

      c Fire extinguishers (carbon dioxide
        and soda ash-acid types)

      d Portable combustible gas indicator

      e Combustible gas alarms in hazardous
        locations at large plants
      f Oxygen deficiency indicator

      g Portable air blower

      h Hose mask or compressed-air,
        demand-type mask
      i Two or more canister gas masks or
        compressed-air masks for chlorine

      j Miner's safety-cap lights
Cooperative efforts of designing engineers
in providing safe structures and of all
employees in exercising reasonable pre-
cautions in the course of their work are
needed.  The responsibility of management
to provide adequate training in the safe
operation of all aspects of the wastewater
treatment plant is also mandatory.

1  "Safety in Wastewater Works, " Manual
     of Practice No.  1.  FSIWA,
     Washington, D.C. (1959)

2  "Sewage Treatment Plant Design, "
     American Society of Civil Engineers
     and the Water Pollution Control
     Federation, Washington, D.C. (1959)

 Because of the many hazards from gases,
 infection and physical injuries in the operation
 of wastewater treatment plants, maintenance
 of such systems can be a dangerous occupation
 if adequate safety precautions are disregarded.
 By the use of sensible safety measures, these
 dangers can be minimized and serious
 accidents can be avoided.
 This outline was prepared by P. F. Hallbach,
 Chemist, National Training Center, OWP,
 EPA, Cincinnati, OH 45226.

                           SCREENING - METHODS AND PURPOSES

 Screening of wastewater is conducted as a
 preliminary treatment step to remove large
 suspended materials which may be harmful
 to other plant operations.

 In general, screening operations are of two

 A Screening

   Screening and removal of solids for sub-
   sequent disposal (usually by burial) is
   generally achieved by using:

   1  Bar screens or bar racks

   2  Drum screens

   3  Vibrating screens

   4  Disc screens

   The simplest form of screening,  the bar
   rack, consists of parallel vertical  bars
   inclined to the flow in order to facilitate
   hand cleaning.   This  is accomplished by
   means of a  long-handled rake.

   In some installations, fixed trash racks are
   movable and can be raised for  cleaning.
   In this case, dual channels are needed in
   order to have one rack in service at all

   Mechanical cleaning is done by moving
   rakes attached to an endless  chain.
   (Figure 1)

   Drum and disc screens are the most
   widely accepted screens for domestic
   sewage.  Sewage flows through the  screen
   depositing material on the outside.  As
   the screen rotates, material is brushed or
   jetted off into a screen pit where it is
   removed by a bucket  elevation.
   (Figures 2 and 3)

Figure 1:  Vertical Section of Bar Screen and
          Mechanical Rake.
   Vibrating screens have received much
   favorable acceptance in industrial
   applications for removal of organic solids
   which would otherwise drastically over-
   load the treatment plant.

   Solids removal by use of bar screens is
   negligible.  Fine screens average
   approximately 10 percent removal of
   suspended solids and are primarily used
   to remove fibrous industrial wastes.

B  Comminution or Grinding
   In cases where grit  is not a problem, or
   following grit removal, incoming material
   is ground or chopped by means of
   oscillating cutter bars to reduce large
   materials to a size that can be handled
   in the treatment processes.

Screening - Methods and Purposes
                                Spray Pipe
                             /"and Nozzles
       yt"V'' ^i    Front View
               Figure 2
             Disc Screen
There are three major types of equipment
in general use for reducing the size of
suspended solids:

1 The  comminution consists of a rotating,
  cutting screen.  The sewage flow passes
  through the screen and out the bottom
  end of the rotating drum. (Figure 4)

2 Barminutors combine the design of the
  bar screen with a travelling grinder
  which moves up and down the rack to
  shred the solids collected on the screen.

3 Grinders and shredders of varied design
  are available for reducing the  size of
  solids removed from bar screens.

In addition, grinders are frequently used
at the waste source to reduce the solids
to an acceptable size.  The home garbage
disposal unit and its commercial and
industrial counterpart are examples of
such units.
                                Spray Pipes
                                                         Screen Covered
                                                  ••vft.Qv:-%' v;Vv^v ;';/.•'.;;?
                                             End View
                                  Figure 3.  Drum Screen

                                                           Screening - Methods and Purposes
                                                   Rotating, cutting
                            Figure 4.  Cutting Screen or Comminuter

 A  Protection

    Removal of such solids as large sticks,
    glass,  metal,  etc., protects the sewage
    treatment equipment from damage.

 B  Reduce Maintenance

    Removal or grinding of large suspended
    solids  such as rags, sticks, and certain
    types of commercial and industrial wastes
    reduces the potential of clogged pumps and
    pipe lines with the attendant maintenance

 C  Increase Plant Efficiency

    Reducing the  size of organic solids by
    grinding or communition increases surface
    area available to bacteria,  thus improving
    digester efficiency.

1 Fair, G. M. and Geyer, J. C.,  Elements
     of Water Supply and Waste Water
     Disposal,  John Wiley & Sons,  (1958).

2 Water Pollution Control Federation,
     Wastewater Treatment Plant Operator
     Training Course Two,  WPCA,
     Washington, B.C.. (1967).

3 Federation of Sewage and Industrial Wastes
     Associations,  Sewage Treatment Plant
     Design, Washington, D. C, (1959).

4 Water Pollution Control Federation,
     Operation of Wastewater Treatment
     Plants, Washington, D. C.,  (1966).

This outline was prepared by Lyman J.
Nielson, Chief, Training, Pacific Northwest
Water Laboratory,  Corvallis, Oregon.


 Grit chambers are used ahead of primary
 treatment to remove heavy solids which may
 be harmful  to plant operation and equipment.

 Grit consists primarily of inorganic materials
 such as sand, gravel, cinders, glass, and
 silt and may include organic materials such
 as coffee grounds, fruit seeds, grain, rags,
 paper  and bits of meat and vegetables.
 Removal  of the inorganic substances in ad-
 vance  of pumps and treatment units prevents
 wear of machinery and unwanted accumulation
 of grit in settling  tanks and facilitates the
 handling of  sludge produced by various treat-
 ment processes.

 In separate sanitary systems, grit originates
 in wash water from kitchens and bathrooms,
 from washings of  floors and from illegal
 ground or storm water connections and from
 industrial processes.

 In the  case  of combined sewer systems, in
 addition to the above,  sand and silt enter the
 systems from street washings through catch
 basins, from damaged pipe joints and drainage
 from excavations.

 Grit removal facilities can be classified into
 two types:

 A Grit Chambers

   Grit chambers are operated at velocities
   low enough to permit capture  of particles
   of specific gravity 2.65 and 2 X 10~2cm
   in diameter.

   The design of grit chambers is based on
   reducing the velocity of incoming sewage
   to approximately 0. 5 to  1. 0 f/s for a
   detention time of one minute.   Generally
   the decrease in velocity is accomplished
   by an increase in  cross sectional area.
    Depending on the range in flow,  it may be
    necessary to provide more than one
    chamber in order to maintain design
    velocity.  Chambers are also designed so
    that the sewage enters and leaves the
    chambers with a  minimum of turbulence.
    In smaller plants where mechanical grit
    removal equipment is not feasible, at
    least two chambers are required to permit
    manual removal of accumulated grit.
    (Figure 1) As manually cleaned chambers
    do not  produce a  washed grit, a consider-
    able amount of organic  matter is included
    with the grit.  Mechanically  cleaned grit
    chambers are cleaned periodically by
    some type of collection mechanism and
    equipment for moving the collected grit
    to a point of disposal.

 B Detritus Tanks

    Detritus tanks are operated at a relatively
    constant level and produce a settled grit
    containing considerable amounts of
    organic material which must be removed
    from the grit before disposal.  This
    material, or detritus, can be removed
    by one of the following:

    1  Re-suspension of the detritus by
       injection of compressed air.

    2  Detritus removal by  use of a  grit washer.

    3  Mechanical scraper for grit removal
       operated in such a manner as to flush
       the  detritus back into the sewage flow.

 Grit chamber design requires data on volume
 and fluccuation of sewage flow and type and
 quantity of grit.

 A  Quality

    Grit types include sand,  gravel,  silt,
    ashes, clinkers,  and miscellaneous debris
    washed from streets.  Household dis-
    charges,  particularly from homes
 SE.TT.pp.23. 7.71

Grit Removal - Principles and Methods
                                  Area A

// ' / '/ / / A

/ f / /

f i

Weir "*•
Grit >k.
////////// / / I I// l\**~* "*•• •","


                                                                 Flushing sump
                                     GRIT  CHAMBER
                                         Figure 1
   equipped with garbage grinders, contribute
   egg shells, bone chips,  coffee grounds,
   and similar material.

B  Quantity

   Quantities of grit vary depending upon:

   1  Street surface  conditions

   2  Area served by the sewer system

   3  Climatic conditions

   4  Types of sewer inlet  structures

   5  Maintenance of catch basins

   6  Amount of storm water diverted from

   7  Sewer grades

   8  Condition of  sewer system
   9 Industrial wastes

  10 Use of household grinders

C  Design Theory

   1 A principal feature of grit chamber
     design is the use of differential
     sedimentation.  Successful grit
     chamber operation is possible because
     of the difference in settling rates
     between inorganic grit particles and
     organic slides.

   2 Settling characteristics of the  grit
     particles to be removed provides the
     basis for chamber design.  The design
     loading is normally expressed in
     surface overflow rate with depth
     qualified,  or as linear flow velocity
     with length as a qualifier.

                                                  Grit Removal  - Principles and Methods
Size of Grit
Average Settling Velocity of Theoretical Maximum Permissible
Quartz Particles (specific Overflow Rate for Substantially
gravity 2.65) in Water, Fpm Complete Removal (Gpd per Sq Ft)

8. 1
Gravity 2.65
128. 000
Gravity 2 . 0
77, 600
Gravity 1.5
38, 800
14. 000
(Sewage Treatment Plant Design -- FSIWA Manual of Practice No. 8)
  From Table 1 it can be seen that a grit
  chamber designed to remove 100% of
  minimum sized grit would also remove
  all larger grit particles.

  The theoretical detention time is that
  required for the minimum size particle
  to reach the bottom of the tank for

  Other factors affecting removal of grit are:

  a  Turbulence of flow in the chamber
     which may hinder settling.

  b  Bottom scour is an important factor
     in grit chamber efficiency.  Re-
     suspension and/or movement of
     settled grit, because of the flow
     velocity above a certain critical
     velocity, may be the controlling
     factor in determining flow velocity
     in the chamber.

3 Velocity control
  Because of variations in flow, it is
  necessary to design the structure to
  maintain the design velocity.
     a.  Proportional weir

     b  Sutro weir

     c  Rectangular control section

     d  Parshall flume

     e  Mechanical velocity control devices

   4 Other design considerations

     a  Accessibility of chamber and
        appurtenances for cleaning and

     b  Grit storage in chamber

     c  Method of grit removal

     d  Arrangement of units


1  Fair, G.M. and Geyer,  J. C.  Elements
     of Water Supply and Wastewater
     Disposal, John Wiley & Sons,  (1958).

Grit Removal - Principles and Methods
  Water Pollution Control Federation,            4  Water Pollution Control Federation,
     Wastewater Treatment Plant Operator             Operation of Wastewater Treatment
     Training Course Two,  WPCA,                     Plants, Washington, B.C.,  (1966).
     Washington,  D.C.,  (1967).
                                                  This outline was prepared by L. J. Nielson,
  Federation of Sewage and Industrial Wastes       Sanitary Engineer,  Division of Manpower
     Associations,  Sewage Treatment Plant         and Training. OWP. EPA, Pacific Northwest
     Design, Washington, D.C.,  (1959).            Water Laboratory,  CorvaUis, OR 97330.

                              FLOW MEASUREMENT DEVICES

 Flow measurements are among the important
 data collected as part of wastewater treatment
 operations.  Such measurements are used to
 interpret treatment plant loadings, and are
 required to assist the operator in evaluating
 the overall plant condition.  Flow data are also
 valuable in determining and/or forecasting
 future needs for plant expansion.  If the
 analysis of plant operation data involves quan-
 titative considerations, the accurate  measure-
 ment of flow assumes a level of importance
 equal to that of  the laboratory and analytical

 In the following discussion procedures both
 for measurement of stream flow and  waste
 discharges are  described.

 Flow is the rate at which a volume of water is
 transferred, or moves through a given section,
 in time.   Flow is commonly expressed in
 equation form as:

          Q =  V/T

 where:   Q is  the flow rate

          V is  the volume

          T is  time

 Other relationships are shown by:

   v  = 1/t and V  =  al

 where:   v  is velocity
          1 is the length of section having
           cross-section area a

          T is  time

          V is  volume

 Flow (Q)  is obtained by measuring the cross-
 sectional area  (a) and velocity (v) of the water
 moving past a point in the channel during a
 specified time  period (T).

 A Gauging of Streams and Rivers

    1  Current Meter

       The current meter is a device for
       measuring the velocity of a flowing
       body of water.  The stream cross
       section is divided into a number of
       smaller sections, and the average
       velocity in each section is determined.
       The discharge is then found by summing
       the products of area and  velocity of
       each section.

    2  Stage-discharge relationships

       Large flows usually are measured by
       development of and reference to a
       stage-discharge curve; this procedure
       has long been used by the U.S.
       Geological Survey.  Such gauging
       stations are composed of a control
       structure located downstream of the
       location of measurement and  some
       type  of water level indicator which
       identifies the height of the water surface
       above a previously determined datum.

       Location of the control structure so that
       reliable measurements of flow will be
       obtained at all river stages is particularly
       important.  The water level may be
       continuously recorded by an automatic
       recorder located in a wet well or may
       be indicated directly on a staff gauge
       located at the bank of the river.   Such
       stations must be calibrated by measure-
       ment of flow by velocity-area methods
       (current meter) at all expected stages
       of river flow.

    3  Weirs

       A weir may be defined as a dam or
       impediment to flow, over which the
       discharge conforms to an equation.
       The edge or top surface over which
       the liquid flows is called the weir crest.

 Flow Measurement Devices
      The sheet of liquid falling over the weir
      is called the nappe.  The difference in
      elevation between the crest and the liquid
      surface at a specified location, usually
      a point upstream, is called the weir head.
      Head-discharge equations based on pre-
      cise installation requirements have been
      developed for each type of weir.  Weirs
      so installed are called standard weirs.
      Equations for non-standard installations
      or unusual types may be derived

      "Weirs are simple, reliable measurement
      devices and have been investigated
      extensively in controlled experiments.
      They are usually installed to obtain
      continuous or semi-continuous records
      of discharge.  Limitations of weirs
      include difficulty during installation,
      potential siltation in  the weir pond, and
      a relatively high head requirement,
      0. 4 - 2.0 feet.  Frequent errors in weir
      installation include insufficient attention
      to standard installation requirements
      and failure to assure completely free
      discharge of the nappe.

      a Standard suppressed rectangular weir

        This type of weir is essentially a dam
        placed across a channel.  The height
        of the crest is so controlled that
        construction of the nappe in the vertical
        direction is fully developed.  Since
        the ends of the weir are coincident
        with  the sides of the channel lateral
        contraction is impossible.   This weir
        requires a channel of rectangular
        cross section, other special installation
        conditions, and is  rarely used in
       plant  survey work. It is more
        commonly used to  measure the dis-
        charge of small streams.

        The standard equation for discharge
       of a suppressed rectangular weir
       (Francis equation) is:
        Q  = 3.33 LH
        Q  = discharge, cfs
        L  = length of the weir crest, feet

        H  = weir head, feet

        The performance of this type of weir
        has been experimentally investigated
        more intensively than that of other
        weirs.   At least six forms of the
        discharge equation are commonly
        employed.  The standard suppressed
        weir is  sometimes used when data
        must be unusually reliable.

     b  Standard contracted rectangular weir

        The crest of this type of weir is
        shaped like a rectangular notch.  The
        sides and level edge of the crest are
        so removed from the sides and
        bottom of the channel that contraction
        of the nappe is  fully developed in all
        directions.  This weir is commonly
        used in  both plant  surveys and
        measurement of stream discharge.

        The standard equation for discharge
        of a contracted rectangular weir
        (corrected Francis equation) is:
        Q  = 3.33 (L - 0.2H)H
        Q  = discharge, cfs
        L  = length of the level crest edge,

        H  = weir head, feet
     0.2H  = correction for end contractions
             as proposed by Francis

     c  Cipolletti weir

        The Cipolletti weir is similar to the
        contracted  rectangular weir except
        that the sides of the weir notch are
        inclined outward at a slope of 1
        horizontal to 4 vertical.  Discharge
        through a Cipolletti weir occurs as
        though end  contractions were absent
        and the standard equation does not
        include a corresponding factor for

                                                             Flow Measurement Devices
 The standard equation for discharge
 through a Cipolletti weir is

   Q =  3.367 LH3'2


   Q  *  discharge, cfs

   L  -  length of the level crest edge, feet

   H  =  weir head, feet

   The discharge of a Cipolletti
   weir exceeds that of a suppressed
   rectangular weir of equal crest
   length by approximately 1 percent.

d  Triangular weirs

   The crest of a triangular weir is
   shaped like a V-notch with sides
   equally inclined from  the vertical.
   The central angle of the notch is
   normally 60 or 90 degrees.  Since
   the triangular weir develops more
   head at a given discharge than does
   a rectangular shape,  it is especially
   useful for measurement of small
   or  varying flow.  It is preferred for
   discharges less than 1 cfs,  is as
   accurate as other shapes up to 10
   cfs,  and is commonly used  in plant
                                                        The standard equation for discharge
                                                        of a 90° triangular weir (Cone
                                                        formula) is

                                                          Q =  2.49H2'48


                                                          Q =  discharge, cfs
                                                          H =  weir head, feet
The head on a triangular weir is
commonly measured at the crest
itself,  rather than at a point
upstream.  Crest height and head
are measured to and from the point
of the notch,  respectively.

Accuracy and installation

Quotations  of weir accuracy express
the difference in performance between
two purportedly identical weirs and
do not  include the effects of random
error in measurement of head.  Weirs
installed according to the following
specifications should measure dis-
charge within± 5% of the values
observed when the previously cited
standard equations  were developed.

1) The upstream face of the bulkhead
   and/ or weir plate shall be smooth
   and in a vertical plane perpendicular
   to the axis of the channel.

2) The crest edge  shall be level, shall
   have a square upstream  corner,
   and shall not exceed 0. 08 in.(2 mm)
   in thickness. If the weir plate is
   thicker than the  prescribed crest
   thickness  the downstream corner
   of the crest shall be relieved by a
                                                        3) The pressure under the nappe
                                                           shall be atmospheric.  The maxi-
                                                           mum water surface in the down-
                                                           stream channel shall be at least
                                                           0. 2 ft.  below the weir crest.
                                                           Vents shall be provided at the
                                                           ends of standard suppressed weirs
                                                           to admit air to the space beneath
                                                           the  nappe.

Flow Measurement Devices
        4) The approach channel shall be
           straight and of uniform cross
           section for a distance above the
           weir of 15 to 20 times the max-
           imum head,  or shall be so
           baffled that a normal distribution
           of velocities exists in the flow
           approaching the crest and the
           water surface at the point of head
           measurement is free of disturb-
           ances. The cross-sectional area
           of the approach channel shall be
           at least 6 times the maximum
           area of the nappe at the crest.

        5) The height of the  crest above the
           bottom of the approach channel
           shall be at least twice, and
           preferably 3 times, the maximum
           head and not less than 1 foot.
           For the standard  suppressed weir
           the crest height shall be  5 times
           the maximum head.  The height
           of triangular weirs shall be
           measured from the channel
           bottom to the point of the notch.

        6) There shall be a clearance of at
           least 3 times the  maximum head
           between the  sides of the channel
           and the intersection of the max-
           imum water surface with the
           sides of the weir  notch.

        7) For standard rectangular
           suppressed, rectangular con-
           tracted, and Cipolletti weirs
           the maximum head shall  not
           exceed 1/3 the length of the
           level crest edge.

        8) The head on the weir shall be
           taken as the difference in
           elevation between the crest and
           the water surface at a point
           upstream a distance of 4 to 10
           times the maximum head or a
           minimum of 6 feet. For
           triangular weirs the head shall
           be taken as the difference in
           elevation between the point of
           the notch and the  water surface
           at the crest itself.
      9) The head used to compute
        discharge shall be the mean
        of at least  10 separate measure-
        ments taken at equal intervals.
        The head range of the measuring
        device shall be 0. 2 -  1.5 feet.

   The capacities of weirs which con-
   form to these specifications are
   indicated in Table 1.

4  Parshall flume

   The Parshall flume is an open con-
   stricted channel  in which the rate of
   flow is related to the upstream head
   or to the difference between upstream
   and downstream  heads.  It consists
   of an entrance section with  converging
   vertical walls and level floor,  a throat
   section with parallel walls and floor
   declining downstream,  and  an exit
   section with diverging walls and floor
   inclining downstream.  Plan and
   sectional views are shown in Figure 2.
   Advantages of the Parshall flume
   include a low  head requirement,
   dependable  accuracy,  large  capacity
   range,  and  self cleaning capability.
   Its primary disadvantage is the high
   cost of fabrication; this cost may  be
   avoided by use of a prefabricated
   flume.   Use of prefabricated flumes
   during plant surveys is becoming
   increasingly popular.

   a  Standard equations

      The dimensions of Parshall flumes
      are  specified  to insure agreement
      with standard equations.  Table of
      dimensions are available from
      several sources  •  .  For flumes
      of 6 inch to 8  foot throat width  the
      following standard equations have
      been developed.

      1) 6 inch throat width

           Q =  2.06 H   1>58

      2) 9 inch throat width

           Q =  3.07 H   1<53

                                                            Flow Measurement Devices
                            TABLE 1  DISCHARGE OF STANDARD WEIRS
Crest Length

Contracted Rectangular*
Max. Min.
.590 .286
1.65 .435
3.34 .584
5.87 .732
9.32 .881
13.8 1.03
19.1 1.18
25.6 1.33

28.8 1.48
34.9 1.78
41.0 2.07
47.1 2.37
53.2 2.67
59.3 2.97
Suppressed Rectangular*
Max. Min.
.631 .298
1.77 .447
3.65 .596
6.30 .744
10.0 .893
14.8 1.04
20.4 1.19
27.5 1.34

30.6 1.49
36.7 1.79
42.8 2.08
Max. Min.
.638 .301
1.79 .452
3.69 .602
6.37 .753
10.1 .903
15.0 1.05
20. S 1.20
27.8 1.35

30.9 1.S1
37.1 1.81
43.3 2.11
48.9 2.38 ! 49.5 2.41
55.0 2.68
61. 1 2.98
55.7 2.71
62.0 3.01
90° Triangular*
Max. Min.

6.55 .046


1 H- 0.2 ft, H - 1.5 ft, H -  1/3 L
                        1   lection




^" "^^5^1


^.Woler surface, s


                        FIGURE 2 PARSHALL FLUME

Flow Measurement Devices
        3)  1 to 8 foot throat width

             Q  =  4WH
             Q  =  free-flow discharge, defined
                  as that condition which exists
                  when the elevation of the
                  downstream water surface
                  above the crest, H. , does
                  not exceed a prescribed
                  percentage of the upstream
                  depth above the crest,  H .
                  The prescribed percentage
                  of submergence is 60 percent
                  for 6 and 9 inch flumes and
                  70 percent for 1 to 8 foot

             W  =  throat width,  feet

             H  =  upstream head above the
                  flume crest

     b Head loss

       The head required by a Parshall flume
       is greater  than (H - R ) because H  is
       measured at a point in the converging
section where the water surface has
already begun to decline.  Table 2
indicates the total head requirements
of standard Parshall flumes.  These
losses should be added to the normal
channel depth to determine the
elevation of the water surface at the
flume entrance.  No head losses are
indicated for discharge-throat width
combinations for which H  is less
than 0.2 ft. or greater thin 2/3 the
sidewall depth in the converging

Accuracy and installation require-

A Parshall flume will measure
discharge within + 5% of the standard
value if the following conditions are

1) The dimensions  of the flume shall
   conform to standard specifications.

2) The downstream head, H , shall
   not exceed the recommended
   percentage of the upstream head,
   H .
                                       UNDER FREE DISCHARGE
2. 5
Head Loss, Feet, in Flume of Indicated Width
1 foot
. 14

2 feet

. 16

3 feet

. 12

4 feet

. 10

5 feet

. 08
. 13
6 feet

. 12
. 19
7 feet

. 10
. 17
8 feet

. 05
. 15
. 41
    H   >  0.2,    H   < 2.0
     a  —          a  —

                                                            Flow Measurement Devices
     3)  The upstream head shall be
        measured in a stilling well
        connected to the flume by a pipe
        approximately 1-1/2 inches in

     4)  The flume shall be installed in a
        straight channel with the centerline
        of the flume parallel to the direction
        of flow.

     5)  The flume shall be so chosen,
        installed,  or baffled that a normal
        distribution of velocities exists at
        the flume entrance.

5 Tracer materials

  Techniques,  materials,  and instruments
  are presently being refined to permit
  accurate measurement of instantaneous
  or steady flow with several tracer
  materials.  Measurements are made by
  one of two methods:

  a  Continuous addition of tracer

  b  Slug injection

     With the first method, tracer is
     injected into a stream at a continuous
     and uniform rate; with the second a
     single dose of tracer  material is added.
     Both methods depend  on good trans-
     verse mixing and uniform dispersion
     throughout a stream.  The concentra-
     tion of tracer material is measured
     downstream from the  point of addition.
     When continuous addition is employed,
     flow rates are calculated from the

               q . C = (Q + q) c

     in which q = rate of tracer addition to
     the  stream at concentration,  C,
     Q = the stream flow rate, and c = the
     resulting concentration of the stream
     flow combined with the tracer.  For
     the  slug injection method
        in which Q = the stream discharge,
        S = the quantity of tracer added, c =
        the weighted average concentration
        of tracer material during its passage
        past the sampling point, and At = the
        total time of the sampling period.
        Disadvantages of tracer methods
        include incomplete mixing, natural
        adsorption and interference,  and
        high equipment costs.

   6 Floats

     Floats may be used to estimate the time
     of travel between two points a known
     distance apart.  The velocity so obtained
     may be multiplied by 0. 85 to give the
     average velocity in the vertical.
     Knowing the  mean velocity and the area
     of the flowing stream, the discharge
     may be estimated.  Floats should be
     employed only when other methods are

B  Pipes and Conduits

   1 Weirs and Parshall flumes

     Weirs and Parshall flumes are commonly
     installed in manholes and junction boxes
     and at outfalls to measure flow  in pipes.
     All conditions required for measurement
     of open channel  flow must be observed.

   2 Venturi meters

     Venturi meters,  Dall tubes,  and similar
     type meters  are useful in measuring
     flow in pipes.

     In the Venturi tube, the rate of flow is
     expressed by:

                  2   ^2
            Q  =
                 c  A t
     Q =
where:  C  =  a coefficient (usually unity)

       D   =  diameter of entrance
       D   =  diameter of throat

Flow Measurement Devices
acceleration due to gravity

difference between pressure at
entrance and at throat
     Fig. 2a  - VENTURI METER
   3 Pilot tubes

     Pilot tubes are useful in measuring flow
     in closed conduits.  It should be noted
     that their use in measuring waste flows
     is not recommended as waste solids may
     plug the tube openings and render
     erroneous readings.

   4 Tracer materials

     These methods are popular for measure-
     ment of pipe flow because they do not
     require installation of equipment or
     modification of the flow.  These are
     especially convenient for measurement
     of exfiltration and infiltration.

   5 Depth-slope

     If the depth of the flowing stream and the
     slope of the sewer invert are known,  the
     discharge may be computed by means of
     any one of several formulas.

     a  Manning formula
  n  =  roughness coefficient
  A  =  area of flow,  sq.  ft.

  R  =  hydraulic radius,  ft.

     =  area divided by wetted
        perimeter,  ft.

  S   « slope, ft. per ft.

b Chezy formula

  Q  =  CA \/RS
                                           Q =  discharge,  cfs

                                           C =  friction coefficient
                                           A =  area of flow,  sq. ft.

                                           R =  hydraulic radius,  ft.

                                              =  area divided by wetted
                                                 perimeter,  ft.

                                           S =  slope, ft. per ft.

                                       6  Open end pipe  flow

                                         The following methods can be employed
                                         when other more precise means are not
                                         practical.  They can be employed,
                                         however, only when there is free dis-
                                         charge to the air.

                                         a Coordinate method
                                           (Figures 3,  4,  and 5)

                                           Discharge may be computed by the
                                           following formula;
                                           Q (gpm) =
                                                       1800 AX
                                           A  =  cross sectional area of liquid
                                                 in the pipe (sq.  ft.)

                                           X  =  distance between the end of the
                                                 pipe and the vertical gauge in
                                                 ft.,  measured parallel to the
        Q  »  discharge, cfs

                                                                           Flow Measurement Devices
        Y  =  vertical distance from water
              surface at the end of the pipe  to
              the intersection  of the water
              surface with the vertical gauge,
              in ft.
                             AdJiMlnblc nut so thit
                             X ait* la parallel to Bewnr
                             mni t atla is vertlcftl-
       : (depth In »c»cr) "r= ^§i^^        fc
b = (dlaUnce fro* bottoa of pipe to •urftct of ftlllaf llqold)
            For sloped sewn or
                    Figure 3
                V= Velocity - fps
                A • Cross-Rcrtlontl
                arm (an fl) if
Flow Measurement Devices
C  Head Measuring Devices

   Several of the above gauging methods
   require the measurement of water level
   in order that discharge may be determined.
   Any device used for this purpose-must be
   referenced to some zero elevation. For
   example, the zero elevation for weir
   measurements is the elevation of the weir
   crest.  The choice of method is dependent
   upon the degree of accuracy and the type
   of record desired.

   1  Hook gauge

     The  hook gauge measures water eleva-
     tion  from a fixed point.   The hook is
     dropped below the water surface and
     then raised until the point of the hook
     just  breaks the surface.  This method
     probably will give the most precise
     results when properly applied.

   2  Staff gauge

     The  staff gauge is merely a graduated
     scale placed in the water so that eleva-
     tion  may be read directly.

   3  Plumb line

     This method involves measurement of
     the distance from a fixed reference
     point to the water surface, by dropping
     a plumb line until it just touches the
     water surface.

   4  Water level recorder

     This instrument is used when a  continu-
     ous record of water level is desired.  A
     float and counterweight are connected
     by a steel tape which passes over a
     pulley.  The float should be placed in a
     stilling well.  A change in water level
     causes the pulley to rotate which, through
     a gearing system,  moves a pen.  The pen
     traces water level on a chart which is
     attached  to a drum that is rotated by a
     clock mechanism.  When properly in-
     stalled and maintained,  the water level
     recorder will provide an accurate,
     continuous record.

Certain portions of this outline contains
training material from prior outlines by
P. E. Langdon, A.E. Becher, andP.F.
Atkins,  Jr.

1  Planning and Making Industrial Waste
     Surveys - Ohio River Valley Water
     Sanitation Commission.

2  Stream Gauging Procedure.  U.S.
     Geological Survey.  Water Supply
     Paper 888.  (1943)

3  King,  H.W.  Handbook of Hydraulics.
     4th Edition.  McGraw-Hill. (1954)

4  Water Measurement Manual.   United
     States Department of the Interior,
     Bureau of Reclamation. (1967)
 This outline was prepared by F.P.  Nixon,
 Chief,  Field Investigation Section,  Edison
 Water  Quality Laboratory,  EPA, and
 modified by L. J.  Nielson,  Sanitary Engineer,
 Division of Manpower and Training, OWP,
 EPA, Pacific Northwest Water Laboratory,
 Corvallis,  OR  97330.


 A Function

   1  Grit removal

   2  Primary sedimentation

      a  Alone or in advance of other

      b  With or without chemicals

   3  Secondary sedimentation - following
      biological treatment

   4  Sludge  thickening

 B Shape and Type

   1  Horizontal flow  - mechanical sludge

      a  Rectangular

      b  Circular

         1) Center feed

         2) Peripheral feed

      c  Imhoff tank

      d  Septic tank

   2  Vertical flow

   3  Tube settler


 A Overflow Rates

   Most State Standards specify maximum
   overflow rates in primary tanks of from
   600 to 1,000 gpd per square feet with
   smaller plants using the lower rates.
   In secondary clarifiers, maximum over-
   flow rates  of 800-1, 000 gpd per square
   feet are commonly specified.

 B Detention Time

   Some states set limits  on both maximum
   overflow rate and minimum detention time.
   A  figure of 2 hours' detention for  primary
    tanks is common although shorter times
    are permitted for primary tanks ahead of
    activated sludge. For secondary tanks,
    2 hours' detention is a common specification.
    The Ten State Standards do not specify
    detention times,  but do set a minimum
    depth of 7 feet on primary and  8 feet on
    secondary tanks, which is tantamount  for
    setting a minimum detention time,  since
       where   T = Detention time (hours)
               D = Tank depth (ft)
              V0 = Overflow rate (gpd per

    Thus,  a tank with an overflow rate of 600
    gpd per sq. ft. and a depth of 7 ft. has a
    detention time of 2. 1 hours.

 C  Weir Loading

    A number of states specify weir loading
    rates of the order of 10, 000-15, 000 gpd per
    lin. ft.  of effluent weir.

 D  Other Criteria

    Some states  specify minimum distances
    from inlet to outlet, scum baffles are
    commonly required, and, as a rule, some
    requirement is set regarding even distri-
    bution  of flow and dissipation of kinetic
    energy at the inlet.

 A  Allen Hazen1

    Hazen's paper published in the Transactions
    of the American Society of Civil Engineers
    in 1904 outlined the commonly accepted
    theory of settling of discrete particles in
    quiescent basins and discussed the effect
    of departures from ideal conditions.
    According to this theory sedimentation
    efficiency is a function  of overflow rate
    and independent of depth.

 B  Thomas R.  Camp2

    Camp's paper on the Transactions of the
    American Society of Civil Engineers in
    1946 elaborated on Hazen's theory,  out-
    lined the use of  settling tube tests to
 EN. DN. sb.2.7. 68

  Sedimentation Basins in Wastewater Treatment
     determine the properties of suspensions,
     discussed settling of flocculent suspensions,
     scour of deposited materials,  the effects of
     short circuiting and turbulence.  He recom-
     mends the use of long shallow tanks for
     sedimentation with the depth being limited
     only by considerations of avoiding  scouring
     velocities and the need for  sludge removal
     equipment.  This paper with the discussions
     that accompany it is  probably the best
     single paper on the subject of sedimentation
     basin design.

     Quote from the discussion of the paper.

     E.  Sherman Chase:   ". . .  . the design
     of practicable settling tanks will continue
     to be based upon judgment, experience,
     and common sense seasoned with a mod-
     erate amount of theoretical computations
     used as aids to judgment. "

     T.  R.  Camp: "This  attitude has undoubt-
     edly been that of most of the designers of
     tanks ....  The moderate amount of
     theoretical computations which Mr. Chase
     suggests for seasoning the judgment has
     unfortunately been so moderate that it has
     been almost completely absent.  Design
     has consisted almost wholly of conformity
     to previous practice  in size and shape
     with little regard for the principles in-
     volved or for the nature and settling
     characteristics of the particles to be
     settled. "

 C  E.  B.  Fitch3

     Fitch, in  Sewage and Industrial Wastes in
     1957, makes the point that in dealing with
     flocculent suspensions a deep tank provides
     better opportunity for particle growth than
     a shallow one and hence that detention
     time cannot be discarded as a criterion in
     settling tank design.  He also points  out
     that hydraulic efficiency or absence of
     short circuiting is not necessarily impor-
     tant to good tank performance.

 D  Ronald T.  McLaughlin4

     McLaughlin, in the Hydraulics Division
     Journal of ASCE in December,  1959,
     points out how the properties of the sus-
     pension determine whether detention time,
     overflow rate,  or both may be important
     to efficient sedimentation.


 A  Flocculation
     Most  of the suspensions dealt with  in
     waste water treatment do flocculate.
   Exception - Grit.
   Activated sludge.

B  Flow Variations
Extreme case -
Intermediate - Raw
   The typical wastewater treatment plant
   is subject to wide variations in flow.
   It is virtually impossible to design  a
   sedimentation tank that will behave in the
   same  way hydraulically with flow varying
   by as  much as a factor of 5-10 from maxi-
   mum to minimum.

C  Solids Removal

   Sludge and scum removal mechanisms
   perturb somewhat the settling of suspended
   matter.   It is necessary to consider a
   portion of the tank volume ineffective be-
   cause of the operation of these mechanisms.

D  Solids Concentration

   It is commonly found that removal efficiency
   of sedimentation basins is higher when deal-
   ing with concentrated suspensions than when
   influent concentrations of suspended  solids
   are low.   It is not usually known why this is
   so.  In some cases,  it .may  be due to differ-
   ences in the size distribution of the sus-
   pension.   Many sewers act as crude settling
   basins which are periodically flushed out.
   At times of flush-out, this relatively coarse
   material reaches the treatment  plant. High
   concentrations of suspended  solids  make for
   more  effective flocculation as well.   This
   accelerates settling.

E  Inlet Design

   A portion of any tank is ineffective  for
   sedimentation because of need to dissipate
   influent kinetic energy and distribute flow
   evenly.  In long tanks, the ineffective
   fraction of the tank is smaller than in short
   tanks.  Flow variations and the  necessity of
   avoiding small openings usually prevent the
   introduction of a controlling head loss to get
   even flow distribution.

F  Density Currents

   Virtually all tanks are affected by density
   currents.  Activated sludge secondary tanks
   always have them, and most primary tanks
   have them from  time to time. Anderson^
   has developed a design of secondary tank
   with an annular weir to improve efficiency
   of circular tanks.  Gould in New York
   adopted another  way of coping with  density
   currents in rectangular secondary tanks.
   He places the sludge hopper  near the effluent
   end of the tank instead of at the  influent end.

                                             Sedimentation Basins in Wastewater Treatment
 G  Resuspension of Deposited Solids

    This limits acceptable horizontal velocities.
    Camp,  using Shields formula, estimates
    that velocities as high as 7-8 fpm are
    acceptable.  In primary tanks at Hyperion,
    there was evidence of resuspension when
    velocities exceeded about  4 fpm. ° The
    presence of density currents can affect
    resuspensirm markedly.  Burgess and his
    colleagues   studied flow patterns in the
    primary tanks of the Northern Outfall
    Works  of the London County Council and
    found a very marked density current.

 Comparatively few extensive studies of plant
 performance to guide engineer in design.

 A NRC Study of Military Treatment Plants8

   Studied 20 months of operating data from
   18 primary plants.  Mean BOD removal
   for the 18 plants ranged from  10 per cent
   to 61 per cent.  Not only was there large
   variation between plants but also large
   variation in a given plant from one period
   to the next.  Average detention period for
   the 18 plants was 3. 77  hours,  average
   overflow rate was 506 gpd per sq. ft.
   Median displacement velocity  was  0. 4 fpm.
   Detention period correlated more closely
   with removal efficiency than did overflow
   rate.  There was no significant difference
   between circular  and rectangular tanks,
   other things being equal.  The following
   formula was used to fit the data for 10
   plants where there was no recirculation  to
   the primary tanks:

   Fractional Removal of      0. 67 T
   Suspended Solids       =  1+ 0. 94 T

 B Data in ASCE - WPCF  Manual of Sewage
   Treatment Plant Design9

   An analysis of data from 32 plants with
   rectangular primary tanks and 25 plants
   with circular primary tanks has been
   made.  The following table shows data on
   size, loading,  and performance at these
              Rectangular Tanks
                            Circular Tanks
Length or diameter
Depth, ft.
Length/ width
Detention time, hrs.
Overflow rate, gpd/ft
Influent suspended
solids, mg/1
Effluent suspended
solids, mg/1
                     Std. Dev.  Mean
                                                      "!t removal suspended
















  1. 12




Multiple correlation analysis were made
on these data, using per cent removal of
suspended solids as the dependent variable
and various parameters as independent
variables.   There was little  to choose
between detention time and overflow rate
as variables in predicting performance.
There was no indication of marked superi-
ority of one shape of tank over the other.
As in the NRC study, there is a wide
scatter  of points about the fitted curve.

Equations fitted to the data were
Circular Tanks

Fraction S. S. removed =•

Fraction S. S. removed =

Rectangular Tanks

Fraction S. S. removed =

Fraction S. S. removed =•
  2.5 T
1 + 3. 8 T

  2. 940
4,100 + V
   .49 T
 1 + .55 T

1,920* V
                                                      where T is detention time in hours
                                                            VQ is overflow rate in gallons per
                                                               day per square foot.

Sedimentation Basins in Wastewater Treatment
C  Secondary Clarifiers at Chicago Activated
   Sludge Plants
  A secondary clarifier in an activated sludge
   plant is  called upon to do a vastly more
   efficient job of solids separation than one
   expects  of primary tanks.  The influent
   contains thousands of mg/1 of suspended
   solids and the effluent is expected to con-
   tain only tens of mg/1 of suspended solids.
   Thus, we look for 99 percent or more
   removal of suspended solids.  To achieve
   thjs, it  is essential that the activated
   sludge be well flocculated and that only a
   small amount of the suspended solids be
   in small particles.
   An analysis of two years operating data
   from five of the operating batteries at
   the three large Chicago activated sludge
   plants has been made to get some insight
   into the  importance of various operating
   variables in determining plant performance.

   The analysis showed clearly the superiority
   of the Anderson design with annular weirs
   over the older design with peripheral weirs.
   Overflow rate  was not an important deter-
   minant of effluent  suspended solids,
   although the five batteries had an average
   overflow rate of over 1, 200 gpd per sq. ft.
   Temperature had a significant effect on
   clarifier efficiency.  An organic loading
   parameter, pounds of BOD per day per
   pound of mixed liquor suspended  solids,
   had a greater effect than either of the other

   The plants had average loadings of . 19
   pounds of BOD per day per pound of mixed
   liquor suspended solids with a range of
   monthly values of  this parameter from
   .09 to .51.   Effluent suspended solids for
   all of the plant units were 15 mg/1, with
   monthly averages  ranging from 5 to 96

   Sludge volume index was not a significant
   index of performance.  It should be pointed
   out, however,  that sludge volume indices
   were quite low, averaging 75 and varying
   from 46  to 139.

   This analysis indicates that with well
   flocculated activated sludges excellent
   solids separation can usually be obtained
   at overflow rates considerably higher
   than those usually recommended However,
   from time to time  one must expect the
   system to get out of control and suspended
   solids carry-over  in the  effluent to occur.

 In spite of the fact that theoretical considera-
 tions indicate that overflow rate should be
 a more significant parameter than detention
 time in design of sedimentation basins, plant
 performance data do not support the superiority
 of one design parameter over the other in
 plants with conventional depths.

 Sedimentation basins generally show rather
 erratic performance in time.  This is  probably
 due  at least in part to the inherent instability
 of flow patterns in basins with horizontal
 velocities  low enough to prevent resuspension
 of deposited material.  Flow fluctuations,
 changes in waste composition, wind, and solar
 radiation  are other perturbing influences.

 Although circular horizontal flow tanks are
 notoriously prone to  short circuiting their
 performance in solids removal appears to  be
 as good as that of rectangular  tanks similarly
 loaded.  The lower maintenance costs  of sludge
 removal mechanisms in circular tanks is
 probably the  most important factor in choosing
 between circular and rectangular tanks.

 There is no rational  basis for  the relatively
 low  overflow rates set by most of the state
 design standards.  At small plants where the
 marginal  cost of providing additional tank
 capacity is proportionately much less than in
 larger plants,  there  is probably not much
 reason to skimp on basin size,  but in larger
 plants there may be significant economy in
 using higher  rates.   Overflow  rates much
 higher than the conventional 600-1, 000 gpd
 per  sq. ft.  are used in many plants with good

 There is little reason for maintaining low weir
 loading rates in primary tanks.  In secondary
 tanks following activated sludge low weir
 loadings are  important.

 The  tube settlers1^ that have been introduced
 recently have not as  yet been tested enough
 for any conclusion to be reached as to  their
 general usefulness in wastewater treatment.
 This development will be watched with interest.

 1  Hazen,  Allen.
       ASCE, 53.
On Sedimentation.  Trans.
45-88.  1904.
 2  Camp, Thomas R.   Sedimentation and the
       Design of Settling Tanks.  Trans.
       ASCE III.  895-957.  1946.

                                            Sedimentation Basins in Wastewater Treatment
3  Fitch, E. B.  The Significance of
     Detention in Sedimentation.  Sewage
     and Industrial Wastes 29.  1123-1133.

4  McLaughlin, Konald T., Jr.  The  Settling
     Properties of Suspensions.  Proc.
     ASCE. Jour. Hydraulics Div. 85.
     No. HY-12.  9-41.  1959.

5  Anderson, Norval E.  Design of Final
     Settling Tanks for Activated Sludge.
     Sewage Works Journal 97.  50-65.

6  Theroux, Robert J.  and Betz, Jack M.
     Sedimentation and Preaeration Experi-
     ments at Los Angeles Sewage and
     Industrial Wastes 31.  1259-1266.

7  Burgess, S.  G., Green, A. F. , and
     Easterby, Patricia  A.   More Detailed
     Examination  of Flow in Sewage  Tanks,
     Using Radioactive Tracers.  Jour.
     and Proc. Inst. of Sewage Purification,
     Part  2.  184-192.   1960.
 8  Subcommittee on Sewage Treatment.
      National Research Council.  Sewage
      Treatment at Military Installations.
      Sewage Works Journal 18.  789-1028.

 9  Sewage Treatment Plant Design.  WPCF
      Manual of Practice No.  8.  90-91. 1959.

10  Hansen, Sigurd P. , Gulp, Gordon L., and
      Stukenberg, John R. Practical Applica-
      tion of Idealized Sedimentation Theory
      Paper,  Presented at WPCF Conference,
      New York City.  October 10,  1967.
 This outline was prepared by R. L. Woodward,
 Camp,  Dresser and McKee Engineers, Boston,

                          SEDIMENTATION TANK EQUIPMENT

 The primary objectives of sedimentation
 equipment is the removal of settleable solids
 and floatable scum.

 A Primary sedimentation objectives are to
   remove concentrated sludge without
   troublesome septicity.

 B Secondary sedimentation requires prompt
   return of fresh solids with concentration
   as a secondary requirement.

 C Basin,  sludge collection, scum removal,
   drive mechanisms and available equipment
   will be  discussed relative to A and B.

 A General

   Much equipment available, more similar-
   ities than differences.  Three basic shapes
   of tanks:  circular, rectangular, square.

 B Circular Clarifier - Center Inlet

   1  General

      Most common flow pattern.   Sewage
      enters center well, either through side
      of tank, or underneath and up.  Sewage
      flows downward,  then radially, over a
      peripheral weir.

   2  Manufacturers

      Infilco, Carter, Eimco,  Yeomans,  Dorr,
      Rex, Walker, Link-Belt,  Hardinge.

   3  Beam Supported Type

      Scraper blades mounted on truss
      revolve about center shaft scraping
      sludge to  central well.  Supported from
      beams spanning tank.  Full weight and
      torque carried by beams.  For small
      tanks,  usually 50 ft. in diameter or
      less.  Motor driven at center.  Skimmer
      connected to same shaft.

   4  Center Column Type

      For larger tanks up to 200 ft. diameter.
      Scraping mechanism similar to beam
      supported type.  Scraper assembly
     suspended from a turntable carried by
     a central column.  Rotated by means
     of motor driven gears mounted on a
     fixed bridge.  Sewage enters up through
     hollow column,  then flows radially.

   5  Peripheral Drive

     Center column.   Rotating bridge drives
     scraping assembly.  Driven peripherally
     by motor driven wheels on wall of tank.
     Not too common in New England.  Snow
     and ice problems,  Manufacturers:
     Infilco, Eimco,  Walker.

   6  Suction Type

     For secondary sludge, mainly activated
     sludge.  Suction pipes mounted on scraper
     truss.  Suction  created by hydrostatic
     head.  Eimco, Dorr, Rex, Walker.

   7  Radial Chain Scraper Type

     Not common.  Radially mounted endless
     chain type, scraping towards  center
     while rotating.  Peripheral drive.  Link-

C  Circular Clarifier  - Peripheral Inlet
                          "" from floor.
                            then upward and
   Sewage enters tangentially into a peripheral
   race.  Skirt extends to 18''
   Sewage flows under skirt,
   over central weir.  Scum, in theory,  remains
   in raceway.   Sludge removal equipment
   bridge supported.  Lakeside, Yeomans, Rex.

D  Rectangular Tanks

   1 General

     Sewage enters at end, is  baffled, flows
     longitudinally to other end, out over

   2 Standard Chain Type

     Oldest type.  Chain and sprocket type.
     Flights attached to chains run on rails.
     Scrape sludge to hopper at inlet end.
     Cross collectors provided in hoppers
     of large tanks.  Rex, Walker, Link-Belt,
     Yeomans,  Jeffrey.

   3 Moveable Bridge Type

     Bridge spans tank width,  running on rails.
     Rakes hung from bridge contact floor and
     move sludge to end  of tank.
 EN.DN, sb. 3. 7.71

 Sedimentation Tank Equipment
       a  Traction drive

          Motor mounted on bridge.  Electricity
          supplied by reel  and cable.  Hardinge,
          Link-Belt, Rex,  Komline-Sanderson.

       b  Cable drive

          Stationary drive  at end of tank.
          Pulls cables attached to moving
          bridge.  Dorr.

 E Square Tanks

    Flow can be center inlet, peripheral weir;
    or straight across flow.  Mechanism
    similar to circular tanks except for exten-
    sion arms which reach into corners, and
    scrape sludge back to  normal radius of
    scraper.  Not common.  Dorr, Walker,
    Link-Belt,  Rex.

 A  Circular Tanks (Primary)

    Skimming device rotates on center shaft.
    Details vary,  but all types force scum
    towards periphery where it is deposited
    in scum box.  Flows or is  flushed to
    scum pit.  Peripheral feed:  Scum in
    raceway flows to a tilting skimming pipe.
    Incomplete removal.  Scum still rises
    in main settling tank.
 B Rectangular Tanks (Primary)

    Return flights travel the surface forcing
    scum to end.  Usually picked up in a
    revolving skimming pipe.  Other types.

 C Secondary Tanks

    It is not standard practice  to install scum
    removal mechanisms on secondary tanks.
    However,  observations in Northeast  Region
    leads us to believe that they are needed.
    We have been thinking of making this a
    firm requirement.

  Slow speed of rotation requires a large speed
  reduction ratio.  Various types of reducers
  and gearing arrangements used, depending
  upon diameter (or length) of tank and sludge
 This outline was prepared by S. C. Peterson,
 Chief, Construction Grants Activities,
 Region I, OWP,  EPA, Boston, Massachusetts.

                             CAUSES OF REDUCED EFFICIENCY
                               IN PRIMARY CLARIFICATION

 A  Settleable Solids

    Over 99% of the settleable solids should be
    removed in a  properly designed and oper-
    ated primary  clarifier.

 B  Suspended Solids

    Fifty to  seventy percent of the suspended
    solids should  be removed in the primary

 C  Biochemical Oxygen Demand (BOD)

    Thirty to thirty-five percent of the BOD
    should be removed in primary clarification.

 D  Floating Solids

    All of the floating solids, grease, scum,
    etc. should be removed.

 E  Chemical coagulation of the influent to the
    primary clarifier may increase removal
    of B and C by ten to twenty percent or
    more under controlled operation.
    Preaeration,  prechlorination and/or
    coagulation would materially increase
    the removable scum, grease and oil
    either as floatable or settleable solids.

 A  Hydraulic overload of a periodic or chronic
    nature may cause reduced retention time
    and/or increased surface or weir overflow
    rates.  Improper distribution has a
    similar effect.

    1  Flow  equalization by retention in the
      collection system, surge tank, or basin,
      during high flow periods may smooth
      out the flow to give manageable control.
   2  Improved baffling in the inlet structure
      may decrease inlet flow velocities and
      improve the tank fraction available for

   3  Proper distribution of flow among two
      or more clarifiers in parallel operation
      may greatly improve overall perform-
      ance.  Baffles converting the splitting
      arrangement from an over to an under-
      flow mode with 6-8 inch head and
      adjustable spacing will help.

B  Short circuiting as a result of improper
   weir adjustment, placement or  geometry
   may cause exceptionally high overflow
   velocities in limited  tank sections with
   obvious effects upon  solids carryover.

   1  Adjust weirs to insure proper leveling
      and eliminate low spots or tilts.

   2  Check weir positions. Are they
      situated so that the natural upflow at
      the end of a tank is not exaggerated by
      weir position.  Are the weirs spaced
      geometrically to utilize the entire
      surface of the tank?

   3  Does the tank show excessive solids
      carryover at corner positions.  If so,
      it may be necessary to block out
      corner weirs.

   4  Do you have sufficient weir length to
      satisfy both surface overflow and
      overflow per lineal feet of weir for the

   5  Check prevailing wind direction over
      the surface.  A  windbreak of trees or
      other type may prevent rolling action
      with a downflow on one side,  upflow on
      the other side of the tank.

C  Inadequate removal of sludge from the tank
   may cause overlong solids retention  with
   development of septic conditions followed
   by the production of floating solids masses

Causes of Reduced Efficiency in Primary Clarification
   and a sludge that is gasey and difficult to
   move without exceptional resuspension.

   1  Pump more frequently while the sludge
      is  in a fresher state and does not tend
      to  gas, cone, bridge,  channel,  or boil
      upward to form resuspended or floating

   2  Pump slowly enough to remove high con-
      centration sludge instead of thin sludge.
      Sludge pumps should have variable
      speed drives to permit adjustment of
      pump rate in line with the situation.

   3  Keep the  sludge blanket low to prevent
      excessive loading on flights or excessive
      remixing of  sludge and clarified liquor.

   4  Adjust speed, flight position, and size
      of  flights so that their movement does
      not cause undue turbulence and
      resuspension of solids.

   5  Inspect, repair and adjust sludge con-
      veyor systems regularly to keep them
      functioning properly.  Sprocket wear on
      long  chains requires regular attention
      to  prevent excessive slack and possible
      misalignment.   For example,  0.005
      inch  wear on each of 400 links represents
      2. 0 feet of extra slack.

   6  Replace broken flight boards as needed
      with  properly sized and installed units
      to  hold the mechanism  in line.

D  Improperly adjusted scum baffles or
   inadequate scum removal  may cause scum
   or floating solids to collect on discharge
   weirs with obvious effects upon effluent
   quality and plant appearance.

   1  Adjust the scum baffles so that floating
      solids will not go over, around or under
      the baffle within usual ranges in plant
      flow  or water levels.

   2  Remove scum frequently enough so that
      unusual accumulations  do not tend to be
      swept under the baffle or cause undue
      difficulty in the scum removal system
      as a  result of solidification into chunks,
      balls or cake.
   3  Inspect and adjust scum removal
      equipment regularly to prevent or
      correct plugged lines,  scum clogged
      conveyors, misalignment, improper
      leveling,  missing or nonfunctioning
      scrapers or squeegies.

E  Primary clarifiers may develop unfavor-
   able density currents as a result of
   temperature and salinity changes, inlet or
   outlet characteristics,wind action, convey-
   or characteristics and speed,  or other
   factors.  For example, a significantly
   warmer influent may rise to the top and
   short  circuit to the discharge weirs.
   A colder influent may move along the
   bottom until it reaches the outlet end and
   cause undue upwelling against the end wall
   of the tank.   Highly saline influents may
   have sufficient density to slide under the
   lighter sludge masses.

   1  Check sources of unusually warm, cold,
      or  saline discharges.   Have them
      decrease the amount,  program the
      discharge or improve mixing and
      equalization at the plant intake.

   2  Preaeration, equalization and mixing
      at the plant will help to minimize

   3  It may be  necessary to decrease the
      speed of sludge and scum flight
      conveyors so that they have less
      tendency to roll the tank contents or
      make other adjustments to attain the
      same objectives.

   4  Weir placement, sludge withdrawal
      rates, inlet baffles, sludge blanket
      depth (or the distance from the top of
      the sludge to the discharge level) may
      require adjustment as discussed earlier.

F  Good housekeeping and maintenance are
   necessary for continued operation and
   effective performance.

   1  Regular cleanup,  lubrication where
      necessary, equipment checkout and
      repair while the problem is small is
      good economy, good public relations,
      and good operational control.

                               Causes of Reduced Efficiency in Primary Clarification
Wash or brush those effluent weirs,
flush sludge and scum lines to avoid
accumulation of excessive slime
growths, deposits or  debris.  Clear
pump lines after each use for sludge
or scum to avoid solidification in place.
Weir cleanup preferably should be a
daily operation.

Each man in the operational scheme
should be encourage to be on the look-
out for unusual noise, vibration,
appearance, or other behavior and to
report these to delegated authority
promptly.  This report  should include
pertinent information, location, and
seriousness of the problem.  These
reports must be recognized and backed
by information feedback to the originator
by his supervisors regarding what may
or is being done about them.  If they are
ignored the system and  the operation
breaks down.
Ill  Most operators are faced with the prob-
 lem of making the best of what they have.
 Often their ingenuity can mean the difference
 between good and poor operation.  The
 operator on the line often is the best source
 of information on precisely what is happening
 or how it can be improved.  Encourage an
 exchange of information among all levels  of
 the staff to promote continuing education and
 cooperative efforts.
 This outline is an expansion of a previous
 outline by Edgar  R.  Lynd,  Municipal Waste
 Treatment Program, State SanitaryAuthority,
 Portland, Oregon; F. J. Ludzack, Chemist,
 National Training Center,  FWQA.

                                SETTLING TANK OPERATION

 The purpose of the settling tank is to remove
 settleable solids and floating solids.  Primary
 and secondary clarifiers are of three basic
 types:  rectangular with mechanical collectors,
 circular with mechanical collectors, and non
 mechanically cleaned hopper bottom tanks.

 A Operation

   1  The objective in the operation of the
      skimmer or scum trough is to get the
      thick  scum into the scum pit, while
      keeping the surface of the clarifier
      free from floating solids.

   2  Reducing the amount of the scum which
      will be pumped to the digester should
      be considered. It will help to pump the
      scum back ahead of the  comminutor
      thus grinding it and giving it another
      chance to settle out in the tank.

   3  The skimmer should be hosed and
      swept clean daily.  The scum pit should
      also be cleaned out after each pumping.

   4  Removal of scum from the scum pit
      should be effected daily.

   5  Crank case oil should be separated and
      buried.   Under no condition should it
      or similar material be pumped to the

 B Excessive Scum Formation

   1  Industrial wastes are frequently the
      cause of considerable quantities of
      floating solids.  Pretreatment screens
      are often removed and when evidence
      of this condition occurs, the industry
      should be contacted.
       Inadequate scum removal often results
       from the gasification and subsequent
       rising of sludge and will be treated
       under sludge removal.

       In circular mechanically cleaned
       clarifiers the skimming belting often
       warps out of shape and ineffectively
       moves the scum.  Whenever the
       belting fails to  do a good job, it should
       be replaced.

       Septic sewage devoid of dissolved
       oxygen will  cause gasification of the
       particles  settling and much of the
       incoming  sludge will float. This will
       be treated under testing and inter-
       pretation of control.

 Sludge removal not only affects the quality
 of the effluents from the primary and
 secondary treatment units,  but also is a
 most important feature in the operation of
 the digester.

 A  Pumping periods must be frequent enough
    to prevent gasification of sludge in the
    hoppers, but periods must not be so
    frequent that sewage instead of sludge is
    pumped to the digester.

 B  If the slopes of the sludge hopper are not
    sufficient,  sludge may adhere to the slope.
    Plants which have hopper slopes less than
    1. 4 vertical to one horizontal will
    probably find that it is necessary to rod
    the hoppers to keep the sludge from

 C  Sludge pump should have some method of
    varying the  speed or pumping rate and
    should be set to pump less than 50 gallons
    a minute. If the pumping rate is too fast
    sewage will be pumped through a hole in

 Settling Tank Operation
   the sludge blanket in the hopper and the
   sludge on the side of the hopper will
   remain there until it gasifies and rises in

D Practice of pumping more water (a thin
   sludge) to the digester than is actually
   needed will cause the digester to operate
   unsatisfactorily; because there is so much
   water, there is not enough room for solids.

E The daily variation in the strength of sewage
   will cause an increase or reduction in the
   quantity of solids deposited as sludge.
   It is often necessary to run settleable
   solid tests on  the raw sewage through a
   24-hour period to get a 2 4-hour picture
   of the variation of solids loading.

F Maximum duration of pumping should be
   figured and at  no single pumping period
   should the total gallons pumped be greater
   than the capacity of the hoppers in gallons.

G Every plant  should be able to see or
   sample the raw sludge.  This is the best
   guide to obtaining a thick sludge.  However,
   many experienced operators have never
   taken the time to run enough percent solid
   tests to train their eyes so that they can
   tell what a thick sludge really is.  If
   possible, stop pumping when the sludge
   contains less than 4% solids.

H Supernatant  solids entering a primary
   clarifier will necessitate extra pumping
   time.   It is desirable to turn a supernatant
   high in solids to the drying bed rather than
   to allow it to return and upset a  primary

I   Quantities of sludge can be estimated by
   running the settleable solids tests on the
   influents of the settling tank. For example
   at a flow of 150, 000 gallons per  day in the
   settleable solids of 6 ml/1 in the raw sewage,
   the  non compacted sludge would  be about
   . 006 X 150, 000 gallons equals 900 gallons
   of sludge to be pumped once daily.

J  Considerable compaction can be effected
   in the hoppers of the clarifier if the size
   indicates that the sludge can be left in the
   hoppers for a longer period of time without
    becoming septic.  On a once a day pumping
    schedule, it may be found that about one
    half of the theoretical amount of sludge
    figured under Part 9, can be pumped into
    the digesters and leave the the hoppers

 K Time clock operation is often necessary
    where the hopper capacity is limited if
    the effluent DO indicates that the sludge
    cannot remain in the clarifiers for a
    longer period of time.  Hourly pumping
    can be estimated by the settleable solid
    tests  taken at hourly intervals during the
    24-hour period as mentioned under Part 5.
    It is also possible to set the time  clock
    to pump 1/2 the calculated theoretical
    amount of sludge and then remove the
    excess  sludge at two manual pumping
    periods during the day.

 Weir placement, adjustment and maintenance
 govern the fraction of tank volume and sur-
 face available for clarification.

 A Cleaning—The weirs scum baffles and
    launders should be hosed and scrubbed
    clean with a stiff broom daily. Weirs
    located at the ends of rectangular tanks
    occasionally have large particles of sludge
    going over the weir.  This phenomenon is
    usually caused by solids creeping up the
    end of a tank which has a heavy growth
    on it.  This creep can be minimized by
    keeping the scum baffles and weirs clean
    far below the water surface.

 B Settling of the tank structure often causes
    weirs to allow more water to flow over
    one portion of the tank than over another.
    Most weirs are bolted through slots to
    permit leveling.  When adjustments are
    made the operators should arrange to have
    a transit or level available to set the weirs
    properly.  A weir which is not level will
    result in short circuiting.

 C Occasionally weirs are not of sufficient
    length to accommodate the necessary flow.
    For every  10, 000 gallons of sewage daily,
    it is necessary to have one foot of weir
    length or more.

                                                                    Settling Tank Operation
 D Baffling is necessary especially in
   rectangular tanks in order to prevent
   short circuiting.  Stratification often
   occurs  in such tanks due to difference
   in temperature of sewage at the top or
   bottom  of the tank and it becomes
   necessary to deflect the thermal currents
   by baffling. In the winter it is sometimes
   necessary to put a baffle at the head of
   the tank to get the warm sewage to drop
   down to the bottom of the tank and under
   the baffle.

 E Occasionally the channel carrying the
   clarified liquid which has passed over
   the weirs will have insufficient capacity
   to carry the necessary quantity of sewage,
   which will back up and submerge the weir.
   This may be due to defects  in the design
   of the launder itself or in the piping.
   Additional pipe or channel capacity may
   be necessary for relief.
B  Overflow Rate--When a plant has the
   flexibility designed into it to permit
   operation of more than one primary
   settling tank, it is necessary to try to
   operate a clarifier at a satisfactory
   surface loading.   The average plant
   will operate satisfactorily at surface
   loading of between 600 and 900 gallons
   per sq ft per day.

C  Temperature of Sewage—Temperature
   has a pronounced affect on the settling
   of sewage.  In cold weather,  there is
   usually an ample supply of oxygen and
   settling is retarded by the viscosity of
   the sewage. In the summertime the
   viscosity of the sewage is low, but there
   is usually the lack of dissolved oxygen
   and the solids start to digest, producing
   gas bubbles which attach themselves to
   the sludge particles and lift them to the
   surface of the clarifier.

 Factors Affecting Control

 A  Detention Period—Most primary treatment
    units will operate satisfactorily with
    detention periods from 1  1/2 to 3 hours.
    Cold weather and the resulting low tem-
    peratures increase the viscosity of the
    sewage and settling is much slower.
    With a long detention period and summer-
    time high temperatures, the plant's
    efficiency may be reduced by a septic
    sewage condition.  This condition is
    brought on by the fact that at higher
    temperatures,  oxygen absorption into the
    sewage is slow and the bacterial rate of
    using up the oxygen is accelerated.
This outline was prepared by J. A.
Montgomery, Sanitary Engineer, FWQA
Manpower and Training Activities, PNWL,
Corvallis, OR.

Settling Tank Operation
                          PRIMARY CLARIFIER CONTROL CHART
In ml/1

Over 2.0
Over 2.0
Over 2.0
Over 2.0
Over 2.0
Over 2.0
Over 2 . 0
Over 2 . 0
Over 2. 0
Over 2.0
Over 2.0
Very Bad
                                                    Probable Cause
                                                  Warm or strong sewage      1, 2, 3
                                                  Warm or strong sewage      1, 2, 3
                                                  Cold or weak sewage
                                                  Stale raw sewage             1
                                                  Warm stale strong sewage    1, 2, 3
                                                  Septic cold or weak sewage   4, 5, 6
                                                  Septic sewage               2, 4, 5, 6
                                                  Warm strong septic sewage   1, 2, 3, 4, 5, 6
                                                  Too much sewage            7
                                                  Too much strong sewage
                                                  Overloaded hydraulically
                                                  and Organically
                                                  Too much stale cold sewage 7
                                                  Too much stale sewage      2, 7
                                                  Too much stale or warm    2, 3
                                                  strong sewage
                                                  Too much septic cold sewage 7, 4, 5, 6
                                                  Too much septic sewage     7, 2, 4, 5, 6
                                                  Many reasons              2,3,4,5,6
1. Increase flow to primary clarifier.
2. Prechlorinate so that no chlorine residual is in the effluent.
3. Add aeration or recirculation high in D. O.
4. Add upsewer chlorination so that no chlorine residual in plant influent.
5. Flush sewers routinely.
6. Move sewage rapidly through lift station.
7. Decrease flow to primary clarifier.

                           ANAEROBIC PROCESS PRINCIPLES

Anaerobic decomposition is employed for the
treatment of organic sludges and concentrated
organic industrial wastes.  During the process
volatile organic matter is degraded through
successive steps  to gaseous end products.
These are primarily CO2 and CH4- l1'  Since
molecular oxygen is absent, the removal of
methane and other reduced gases represents
the BOD removal from waste under anaerobic

A  Theory

   1 Organic sludges  go through two basic
     processes during the digestion process--
     liquefaction and gasification.  Liquefaction
     occurs with extracellular enzymes which
     hydrolyze complex carbohydrates to
     simple sugars, proteins to peptides and
     amino acids and  fats  to glycerol and fatty

   2 The ultimate end products of the lique-
     faction process are primarily volatile
     organic  acids which are produced by
     "acid producing" strains of bacteria.
     The acids produced are primarily  acetic,
     butyric and propionic. (*'

   3 During gasification the end products of
     liquefaction are further broken down
     to gaseous end products.   The principal
     components of this gaseous mixture are
     CO2 and CH4.  During a well balanced
     digestion process,  the processes of
     liquefaction and gasification occur

   4 The degree to which the various substances
     present  in sewage sludges and industrial
     wastes will be decomposed will depend on
     their chemical nature.  Woody type ma-
     terial will result in approximately a 40
     percent  humus-like residue.  Soluble
     organics are almost completely
     decomposed.  With the exception of
     hydrocarbons, carbonaceous material
     is quantitatively  converted to CH4  and
     COo.  Free fatty acids will undergo
     80-90 percent destruction,  ester fatty
     acids  65-85 percent and unsaponifiable
     matter 0-40 percent, l1'

   5 It has been found convenient to describe
     the digestion process in three stages:
      a Acid fermentation stage

      b Acid regression stage

      c Alkaline fermentation stage

      The course of digestion of this three
      stage digestion process is shown graphi-
      cally in Figure 1.

B  Acid Fermentation Stage

   During the acid fermentation  stage,
   carbohydrates (sugars,  starches, etc.)
   are broken down to low molecular weight
   fatty acids, primarily acetic, butyric and
   propionic.  This intensive acid  production
   results in a drop in pH and leads, tp the
   formation of putrefactive odors.' '  The
   organisms primarily responsible for this
   stage of the digestion process are called
   "acid formers. " They transform the waste
   into short chain fatty acids and  are generally
   anaerobic or facultatively anaerobic.   This
   group encompasses a large number of  bac-
   teria with a wide range of talents.  Asa rule,
   the acid formers are less sensitive to
   environmental factors than are  the methane
   formers.  Many of the acid formers  are
   quite versatile as to substrate and end
   product while others are quite limited.
   Hence, in some cases, components of  the
   waste may be taken to short fatty acids by
   a single organism, while in other cases,
   this transformation may require several

C  Acid Regression Stage

   During the acid regression stage, decom-
   position of organic acids and soluble
   nitrogenous compounds occurs  resulting
   in the formation of ammonia, amines,
   acid carbonates and small quantities of
   C°j2. N2, CH4 and H2.  The PH will tend
   to increase during this stage.   By-products
   resulting from acid regression  will include
   H2S, indole, skatol and mercaptans. '*'

D  Alkaline Fermentation Stage

   During the alkaline fermentation stage,
   destruction of celluloses and nitrogenous
   compounds occur.  Low molecular weight
   organic acids produced during the earlier
   stages of the process are broken down to
   CO2 and CHj..   The organisms  primarily
   responsible for the process are the
SE. AN. 8. 8. 70

Anaerobic Process Principles
                  Acid fermentation
Acid regression
Digestion of resistant materials

                                                     Relative gas  production
                                    Time of digestion,  days

                       Course of digestion of sewage solids (after Grune, 1956)

                                           FIGURE 1
   spore-forming anaerobes,  the methane
   bacteria, and fat-splitting organisms.
   The methane bacteria are strict anaerobes,
   nonspore forming and require CC>2 as an
   hydrogen donator.   These organisms require
   an inorganic nitrogen source (NH3).  The
   effective pH range for methane formation
   is pH 6.4-7.2.

E  Gas Production

   The gas produced from the digestion of
   sewage sludge and similar organic mixtures
   is composed primarily of CO2 and CH^ with
   small quantities of  NH3,  H2S, H2, N2  and
   O,, present. Gas from a well-digesting
   sludge mixture will contain 25-35 percent
   CC>9  and  6J1-75 percent CH^.  A gas  yield
   of 16-18 ft3/lb of volatile matter destroyed
   can be expected from digesting sewage
   sludge.  The following table from Buswell
   (1939) shows gas production from various
   sewage constituents. '*'

             Crude fibre
ftJ of gas/lb


          A  "Conventional" process generally used for
             treatment of concentrated wastes  such as
             primary and secondary sludges such as at
             municipal sewage treatment plants.

          B  "Anaerobic  contact process" designed to
             handle more dilute  wastes and generally
             applied to specific industrial wastes.

          C  Process Units

             1  Septic tanks

             2  Imhoff tank

                                                                Anaerobic Process Principles
3  Conventional digesters

   a  Standard

   b  High rate(2)

4  Anaerobic contact

5  Anaerobic lagoons


 A Biological - Nutrientsv

    1  Nitrogen and phosphorous - usually
       present in sufficient amounts in domestic
       wastes - may be required in some indus-
       trial wastes.  Nitrogen must be added in
       NHj form,  as NO2,  NO3 forms are re-
       duced and N2 is evolved, hence lost.

    2  Trace  elements - Fe|8) Mn, Mg, K, Ca,
       S, etc.  - seldom a problem as waste
       usually contains sufficient amounts.

 B Physical

    1  Hydraulic loading

    2  Temperature

       a  Mesophilic 85° to 100°F

       b  Thermophilic 120° to 135°F

    3  Mixing

 C Chemical

    1  pH - range from about 6. 6 to 7. 6

    2  Toxic materials

       a  Certain  alkali and alkaline- earth
          are stimulatory at low levels and
          inhibitory aihigher levels as shown
          in Table  I.*8'

       b  Ammonia toxicity

      c  Sulfide toxicity

      d  Heavy metal toxicity1

      e  Toxic organic materials

D  Acclimation

   1  Tolerance to certain cations
      increased by acclimation. '^
                                   can be
                                                IV  OPERATION

                                                 A  Control

                                                    1  Control of the pH of the anaerobic pro-
                                                       cess depends on the maintenance of an
                                                       adequate bicarbonate buffer system.
                                                       A proper buffer system counteracts the
                                                       acidity of the carbon dioxide as well as
                                                       the acidity of the organic acids produced.

                                                    2  Use of ORP(4'12)
                                                               M 0\
                                                    3  Buswellv±0/  lists factors that interfere
                                                       with digestion as:

                                                       a Sudden increase in feed

                                                       b Sudden change in pH of raw waste

                                                       c Sudden slug of inorganic material such
                                                         as Zn, Cu, CN or 'Psalts. "

                                                       d Sudden temperature change

                                                 B  Digester Seeding

                                                    1  Value of adding digested sludge to start
                                                       digesters probably lies in production of
                                                       favorable environmental conditions such
                                                       as a suitable acid/alkalinity ratio as
                                                       much as in the numbers of bacteria

                                                 C  Aids to Digestion

                                                    Distressed digestion can be attributed to
                                                    a number  of factors, all of which directly
                                                    or indirectly alter the microbiological
                                                    environment.  In certain cases, a more
                                                    favorable  environment for these organisms
                                                    can be provided by restoring the favorable
                                                    environment by providing buffing alkalinity.
                                                    Lime has  been  used and reported in many
                                                    cases.  Agricultural ammonia has been      ...
                                                    found to be successful in certain applications.   '
                                                    Buswelr13' suggests return of alkalinity in
                                                    the sludge from secondary digestion.
                                              V  SUMMARY

                                              A  Anaerobic digestion processes are capable
                                                 of treating greater amounts of organic
                                                 matter in less space than aerobic.

                                              B  Sludge accumulation is less because of the
                                                 greater influence of hydrolysis and lower
                                                 rate of growth under anaerobic conditions.

                                              C  Environmental control major factor in
                                                 effective operation.

Anaerobic Process Principles
D  Methane produced represents a useful fuel
   and represents major BOD removal of

   Table 1.  Stimulatory and Inhibitory
   Concentrations of Alkali and Alkaline-
	Earth Cations^5)	

        Concentrations in mg/1

                     Moderately  Strongly
Cation    Stimulatory  inhibitory  inhibitory

Sodium    100-200    3500-5500    8,000

Potassium 200-400    2500-4500   12,000

Calcium   100-200    2500-4500    8,000

Magnesium  75-150    1000-1500    3,000

Certain portions of this outline contain
training material from a prior outline by
J. C. Dietz,  Consultant, Clark, Dietz and
Associates, Urbana, Illinois.

1  Eckenfelder,  W. W.  and O'Connor, D. J.
      Biological Waste Treatment.  Pergamon
      Press.  New York.  1961.

2  Pohland, F. G. and Engstrom,  R. J.
      High-Rate Digestion Control.  Proceed-
      ings 19th Industrial Waste Conference.
      Purdue University.  1964.

3  Imhoff, Karl  and Fair, G. M.  Sewage
      Treatment.  John Wiley and  Sons, Inc.
      New York.  1956.

4  Burbank, N.  C., Cookson, J. T.,
      Goeppner, J.  and Brooman,  D.  Isolation
      and Identification  of Anaerobic and Facul -
      tative Bacteria Present in the Digestion
      Process.  Proceedings of the 19th
      Industrial Waste Conference.  Purdue
      University.  1964.

5  McCarty, Perry L.  Anaerobic Waste
      Treatment Fundamentals. Public Works.
      9:107-112,  10:123-126, 11:91-94,
      12:95-99.  1964.
 6  Cooke, William B.  Fungi in Sludge
      Digesters.  Proc. 20th Ind. Waste
      Conference.  Purdup University.
      Ext. Ser. 118.   6.  1965.

 7  Speece, R.  E.  and McCarty, P.  L.
      Nutrient Requirements  and Biological
      Solids  Accumulation in  Anaerobic
      Digestion. Proceedings of First
      International Conference on Water
      Pollution Research.   Pergamon Press.
      London.   1964.

 8  Pfeffer, J.  T.  and White,  J. E.  The Role
      of Iron in Anaerobic Digestion.  19th
      Industrial Waste Conference Bulletin.
      Purdue University.  Lafayette, Indiana.

 9  Kugelman,  I. J. and McCarty, P. L.
      Cation Toxicity and Stimulation in
      Anaerobic Waste Treatment, II, Daily
      Feed Studies.  19th Industrial Waste
      Conference Bulletin.  Purdue  University.
      Lafayette, Indiana.  1964.

10  Lawrence,  A. W.  , McCarty,  P.  L. and
      Guerin,  F. J.  The Effects  of Sulfides
      on Anaerobic Treatment. Proceedings
      19th Industrial Waste Conference.
      Purdue University.  1964.

11  Rudolfs, Willem.   Industrial Wastes.
      Reinhold Publishing Company.  293-294.
      New York.  1953.

12  Biological Treatment, Sewage  and Industrial
      Wastes.   2.  Reinhold Publishing Company.
      New York.  1958.

13  Buswell,  A. M.  Methane  Fermentation.
      Proceedings 19th Industrial Waste
      Conference.  Purdue University.  1964.

14  Heukelekian, H. and Heinemann, B.  Sewage
      and Industrial Wastes.  11.  436-444.  1939.

15  Cooper, J.  F. , Hindin,  E. and Dunstan,
      G. H.  Agricultural Ammonia for  Stuck
      Digesters.  Proc. 20th Ind. Waste Conf.
      Purdue University. Ext. Ser.  118. 126.

 This outline was prepared by Paul F.  Hallbach,
 Chemist, National Training Center, Federal
 Water Quality Administration, Cincinnati, OH

                                                  Anaerobic Process Principles
                               Table 2


Empirical Equation:

C H O,+ (n - a/4 - b/2) H0O
 nab                 &

         (n/2 - a/8 + b/4) CO2 +  (n/2 + a/8 - b/4) CH4

1  Reactions not involving reduction of carbon dioxide

             CH3COOH -  CO2 + CH4

             4CH3OH -  3CH4 + 2H2O

2  Reduction of carbon dioxide without net decrease

             4HCOOH - CH4 +  3CO2 + 2H2O

   4CH3CH2COOH + 2H2O - 7CH4 + 5CO2

3  Reduction and net decrease of carbon dioxide

             4H2 + CO2 - CH4 + 2H2O
        2CH3CH2OH + CO2 _ CH4 + 2CH3COOH
   4CH3CHOHCH3 + CO2 - CH4 + 4CH3 — CO — CHg + 2H2

   2CH3(CH2)2COOH + CO2 + 2H2O - CH4 + 4CHgCOOH


 A  Use of Imhoff tanks and conventional di-
    gestion processes for industrial wastes.

    1  Economic considerations - large capital

    2  Operational problems - lack of control
      over fermentation.

    3  Presently a part of industrial waste
      treatment when  domestic and industrial
      wastes are treated together.

    4  Conventional digestion used for  certain
      industrial waste treatment facilities.
 B  Present developments and applications of
    anaerobic waste treatment.

    1  Anaerobic lagoons

    2  Anaerobic contact process

    3  Conventional process - simple anaerobic


 A  Design Standards

    1  State regulatory agencies in Illinois,
      Iowa, Nebraska and Minnesota recom-
      mend design loadings of 15 pounds BOD
      per 1000 cubic feet of anaerobic
      pond/ 1)

    2  Requirements of regulatory agencies
      for fill-and-draw lagoons - designed as
      holding lagoons for discharge at high
      stream flows but may operate as
      anaerobic system.

    3  Use of pilot lagoons to determine loading
      rates. ™
B  Local Conditions Affecting Design

   1  Geographic location a factor in loading

      Higher temperatures enable increase
      in loadings

   2  Soil conditions

      a  Rock or high ground water

      b  Pervious soils where water pollution
         may be possibility

      c  Construction of impervious lagoons

      d  Need for soil borings

   3  Prevailing winds and closeness of
      other facilities as odor problem

   4  Receiving waters  - Seasonal variation
      of flow

   5  Seasonal loadings to  lagoons

C  Construction Features

   1  Inlet - Designed  so as to provide rapid
      mixing with existing digester mixture.

      a  Use of recirculation

   2  Outlet - designed to prevent solids loss.

   3  Cover for odor control and prevention
      of heat loss.

      a  Natural cover built up by wastes
         such as paunch manure in meat
        plant wastes,  Coerver.
      b Styrofoam or similar cover such as
        used by Mclntosn •  '  at American
 IN.MET.bi. 37a. 11.66

  Anaerobic Industrial Waste Applications
     4  Recirculation of sludge to seed incoming
        raw waste.

  D  Operation

     1  Use of BOD or COD, and suspended
        solids for determination of efficiencies.

     2  Grease problems for specific wastes.

     3  Determination of sludge accumulations.

     4  Flow measurements of BOD values
        used to determine waste loadings.


 A Description of Process

    1  The process involves the treatment of
       a strong waste by mixing it with
       anaerobic biological substrate and dis-
       charging it after a limited  time based
       on a loading rate to a clarifier.  Sludge
       from the clarifier is returned to mix
       with raw incoming waste to the digester
       as shown on Figure 1.  Provision for
       degassing the  mixed liquor is generally
       provided before clarification to improve

    2  British type anaerobic process involves
       anaerobic contact with pre-mixing
       followed  by sedimentation in a spiral
       tank. < 6)
 B  Design Standards

    1  Loadings of from 0. 15 to 0.20 pounds
       of BOD per cubic foot of digester per

    2  Suspended solids concentration up to
       15, 000 mg/1 apparently provides for
       success of operation.

    3  Process similar to the aerobic activated
       sludge process.

 C  Local Conditions Affecting Design

    1  Small area requirement as compared
       to anaerobic lagoons
    2  Temperature control by heat exchanger

    3  Close control of process

 D  Construction Features and Operation

    1  Use of flow equalization (Figure 2)

    2  Need for digester mixing

    3  Corrosion - resistent materials for
       gas piping, degasifier and digester

    4  Degasifier required prior to sludge

    5  Separators or settling tanks required

    6  Sludge return from separator to raw
       waste line to digester

    7  Flow measuring and recording equipment

    8  Need for anaerobic contact effluent


 A  Description of Process

    1  In this process, wastes are digested
       at controlled temperatures and the
       effluent drawn off at certain levels
       in the digester.

       a  Conventional sludge digestion -
          loadings of 0. 03 -  0. 04 Ibs. volatile
          solids per cubic foot per day.

       b  High rate sludge digestion  - 0. 18
          Ibs.  volatile solids per cubic foot
          per day.

 B  Design Features  (Figure  3)

    1  Gas collection

    2  Digester heating

    3  Sludge removal

    4  Supernatant removal and disposal

                                                   Anaerobic Industrial Waste Applications
A  Anaerobic Lagoons
   1  Meat wastes
      a  Moultrie, Georgia,   treating a meat
         packing waste in an anaerobic lagoon
         14 feet deep and 1.4 acres in surface
         area, followed by an aerobic lagoon
         with a total are a of 19. 2 acre sand a
         depth of 3 feet.  The dentention time is
         6 days in the anaerobic pond and 19 days
         in the aerobic pond. The BOD loading
         is about 0. 014 Ib/day/cu. ft. in the an-
         aerobic stage, and 50 Ibs /day/acre in
         the aerobic stage, with an overall BOD
         loading of 325Ibs/day/acre. Sludge is
         recirculated  in the anaerobic lagoon
         and effluent is recirculated in the an-
         aerobic lagoon.  The BOD of the raw
         waste averaged 1, 100mg/l, and the
         effluent averaged 67 mg/1 over a 4-

      b  Edmonton, Ontario^ anaerobic
         lagoons  show removal as follows:
         suspended solids, 75 per cent; BOD,
         70  per cent;  and grease,  79 per cent.

      c  Union City,  Tennessee    lagoon
         provided BOD, grease and suspended
         solids removals of over 90 per cent.
      d  Luverne, Minnesota    lagoons showed
         removals of  58 per cent BOD at load-
         ings of 16 Ibs.  BOD per 1000 cubic
         feet per day.

      e  Coerver    describes the use of
         shallow anaerobic lagoons for packing
         house waste  treatment at three
         installations in Louisiana.  Average
         BOD removals are 92.4 per cent.
         With an  aerobic lagoon for polishing,
         overall BOD removals of 98 per cent
         are secured.
   2  Corn wet milling wastes
                     (4 5)
      a  Roby,  Indiana  '   American Maize
         Products Company uses 2.4  acre
         anaerobic lagoon to treat 600, 000
         gpd of 2260 mg/1 BOD, temperature
         95°F waste.  Loadings of 14 Ibs. per
         1000 cubic feet with 90 per cent
         BOD removal. Uses styrofoam
         covers for temperature control.

   3  Chemical and fermentation

      a  Terre Haute,  Indiana'^'installation
         removing 60 to 80 per cent BOD
         removal on raw waste of 10, 000
         mg/1 BOD and 30, 000 mg/1 suspend-
         ed solids at 450 Ibs per acre at 4
         foot depth and 220 day retention.

   4  Soy bean  wastes

      a  Taylorville, Illinois  , Allied
         Mills  uses two-level 3.2 mg lagoon
         with 10 foot normal depth,  12 foot
         high level depth.   (Figure  4)
   5  Poultry manure wastes
      The use of anaerobic lagoons    for
      poultry manure wastes in California
      has been successful with no observed

   6  Livestock manure

      Livestock manure anaerobic lagoons
      can be operated successfully with proper
      design and control.  The need for such
      waste treatment will probably increase
      installations in this  particular area.   '

B  Anaerobic Contact Process

   1  Meat wastes

      a  Wilson and  Co. plant at Albert Lea,
         Minnesota <13» l4» 15« 16» 17> with
         digester loadings of 0. 16 to 0.20
         Ibs.  per cubic foot  per day with 90
         to 94 per cent BOD removal.  Raw
         waste strengths of  1300 to 1600 mg/1
         BOD.  Sludge concentrations in the
         mixed liquor from 7000 to 10, 000
         mg/1. Uses vacuum degasification.

      b  Agar Plant  at Momence, Illinois
         uses vacuum degassification results
         in 85 to 92 per cent  BOD removal
         on raw waste strengths of 1500 to
         2000  mg/1 BOD.  Waste flow of
         0. 4 to 0.6 mgd.

Anaerobic Industrial Waste Applications
          Austin, Minnesota plant uses aeration
          for gas removal prior to sludge
          separation.  At loading of 0. 059
          pounds per cubic foot, 96 per cent
          BOD removal achieved on wastes
          of 1400 mg/1 BOD. (6)
 C  Conventional Process
    1  Yeast plants
       a  Standard Brands,  Pekin,  Illinois.
          Six digesters in these stages handling
          225, 000 gallons per day of 10, 000
          mg/1 BOD waste with 10 day deten-
          tion.  Plant built in 1940.   Loaded
          at 0. 108 pounds per cubic  foot.

       b  Crystal Lake Yeast Co.,  Crystal
          Lake,  Illinois.  Two stage digestion
          with four days' detention.   Raw
          waste  BOD 5000 mg/1,  anaerobic
          effluent 1500 mg/1.

    2  Grain waste plants

       a  Peoria, Illinois.  Butanol  acetone
          wastes with raw BOD of 17, 000
          mg/1 loaded  at 0. 114 pounds per
          cubic foot.  With 10 day detention
          effluent of 2400 mg/1 BOD.
      b  Carthage,  Ohio.  Pilot plant at dis-
         tillery  treated 16, 000 mg/1 BOD
         wastes at 0. 143 pounds  per cubic
         foot loading with effluent of 1600
         mg/1 at 14 days' detention.

    3  Cane sugar plants

      Pilot plant studies indicate that the
      waste from cane sugar factories can be
      treated effectively by anaerobic diges-
      tion followed by stabilization  in an oxi-
      dation pond.   BOD reductions in the
      anaerobic portion of the process ranged
      from 60 to 70 percent with 70 percent re-
      ductions achieved in two days detention
      time with a heated digester. '*°'

    4 Antibiotic wastes

      Antibiotic-containing waste slurries
      were reported to be treated success-
       fully by anaerobic treatment.(19)

 A  The use of pilot plant studies on a bench
     or larger scale provides for better design.

     1  Studies indicate lack of nutrients and/
       or presence of toxic materials.

     2  Cost of pilot studies are relatively small
       compared to the total expenditure for the
       installation and can be offset in many
       cases by increased design loadings re-
       sulting in lower first costs of treatment

  B  Effluent from pilot studies can be used for
     evaluation of treatment required following
     the anaerobic process.

  A  Economics

     1  Anaerobic lagoons and anaerobic contact
       process provides excellent and economical
       means of treating certain high strength

     2  Cost figures for packing house wastes
       are shown on Figures 5 and 6.  Costs
       were determined for 0.5,  1.5 and 2.5
       mgd flow with BOD loadings of 5, 000,
       12, 000 and 15, 000 Ibs per day.  Land
       cost for lagoons were $500 per acre.
       Insurance, taxes,  depreciation, power,
       labor and other items were included in
       the annual cost comparison.   Interest
       was taken at five per cent.

     3  Choice between anaerobic contact or
       anaerobic lagoons can generally be
       determined by cost  studies.

  B  Treatment of Anaerobic Effluent

     1  The effluent from the anaerobic con-
       tact process or anaerobic lagoons can
       be treated by conventional aerobic

     2  Odor is not a problem in properly
       designed system.

                                                 Anaerobic Industrial Waste Applications
C  Degree of Treatment

   1 Anaerobic contact and anaerobic
     lagoons can reduce waste BOD by
     90 per cent  or greater.
Degree of treatment depends on loading
rates, temperature and other factors.

                  •MAX. WATER
                   SURFACE 111.0
              RAW WASTE
                         MAX. WATER-
                         SURFACE  IO49I
I    —PUMP




                                                       •*• VACUUM  PUMP
                                                     INF. ELEV. 125.67
                                                                      -WATER SURFACE
                                                                           TO POLISHING
                                      •RETURN SLUDGE

                         ANAEROBIC  CONTACT   PROCESS
                                         Figure 1

                                     Anaerobic Industrial Waste Applications

12 M

UJ   5-



Figure 2

Anaerobic Industrial Waste Applications

                                       DIGESTED SLUDGE
                                                       CONCRETE STOPS FOR
                                                       FLOATING COVER
                                                            PIPE SUPPORT
                                        GAS DOME
                                                       PIPE  SUPPORT
                            SLUDGE   DIGESTER

                                   Figure 3

                            WATER SURFACE= 104.5
                            EFFLUENT BOX
                             8" INFLUENT TO AEROBIC
                             LAGOON ELEV.= 99.5
      LAGOON ELEV. = 93.0
                   Figure 4

Anaerobic Industrial Waste Applications

    < 800,000
    O 600,000
                           FIRST  COST

                    INCLUDING  LAND COST
                               Figure  5

                            Anaerobic Industrial Waste Applications
                   10      1.5
                  CAPACITY- MOD
                     Figure 6

Anaerobic Industrial Waste Applications

 1  Dietz, J. C., Clinebell, P. W., and Strub,
      A. L.  Design Considerations for An-
      aerobic Contact Systems. Jour.  Water
      Poll.  Control Fed.  38, 4,  517.  April

 2  Dietz, J. C., Clinebell, P.W.. and Strub,
      A. L.  Anaerobic  Pre-Treatment of
      Packing House  Wastes.   Fifth Annual
      Sanitary  and Water Resources Engineer-
      ing Conference, Vanderbilt University
      (In Press).

3  Coerver, James G.  Anaerobic and Aerobic
      Ponds for Packing-House Waste Treat-
      ment in Louisiana.  Proceedings of the
      19th Industrial Waste Conference.
      Purdue University.  1964.

4  Mclntosh, G.H., and McGeorge,  G. G.
      Lagoon Treatment of Corn  Wet Milling
      Wastes.  Presented at Indiana Water
      Pollution Control  Association Conference.
      November, 1962.

5  Mclntosh, G.H., and McGeorge,  G. G.
      Keep Waste Water Warm with  Floating
      Plastic-Foam Blanket for Efficient Year-
      Round Lagoon Operation.  Food Pro-
      cessing,  pp 82-86.  January, 1964.

6  Steffen, A. J.  Anaerobic Industrial Waste
      Applications. Presented at Training
      Program, SEC.   1964.

7  Sollo, F. W.  Pond Treatment  of Meat
      Packing Plant Wastes.  Presented  at
      15th Purdue Industrial Waste Conference.
      May,  1960.

8  Stanley, Donald R.  Treatment of Meat
      Packing Plant Wastes  in Anaerobic and
      Aerobic Lagoons.   Presented at  12th
      Ontario Industrial Waste  Conference.
      June,  1965.

9  Rollag, D.A., and Dornbush, J. N. Design
      and Performance  Evaluation of an
      Anaerobic Stabilization Pond System
      for Meat Processing Wastes.  Pre-
      sented at 38th Annual Meeting, Central
      States Water Pollution Control Associ-
      ation,  Albert Lea,  Minnesota. June,

10 Howe, David O.,  Dr, Miller,  Archie,
      P., Etzel,  James E., Dr.   Anaerobic
      Lagooning - A New Approach to Treat-
      ment of Industrial Wastes.   Proceedings
      of the 18th Annual Industrial Waste
      Conference, Purdue  University,  Series
      115,  pp 233-242.  1963.

11  Cooper, R. C., Oswald, W. J., and  Bronson,
      J. C.   Treatment of Organic Industrial
      Wastes by Lagooning.  Proc.  20th Ind.
      Waste Conf.,  Purdue Univ. Ext.  Ser.
      118, 351.  1965.

12  Hart. S.A.,  and  Turner,  M. E.  Lagoons
      for Livestock  Manure. Journ. Water
      Poll. Control  Fed.  37,  11,  1578.  Nov.

13  Schroepfer, G.J.,  Fullen, W. J., Johnston,
      A.S.,  Ziemke, N. R.,  and Anderson, J. J.
      The  Anaerobic Contact Process as
      Applied to Packinghouse Wastes.   Sewage
      and Industrial Wastes, Vol.27, No.  4.
      pp 461-486.  1955.

14  Steffen, A. J.  Full-Scale Modified Di-
      gestion of Meat Packing Wastes.
      Sewage and Industrial Wastes. Vol.
      27, No.  12, pp 1364-1368.  December,

15  Steffen, A. J.,  and Bedker,  M.  Separation
      of Solids in the Anaerobic Contact Pro-
      cess.  Public Works, Vol. 91, No. 7.
      pp 100-102. July,  1960.

16 Steffen, A. J., and Bedker,  M.  Full
      Scale Anaerobic Contact Treatment
      Plant for Meat Packing Wastes.   16th
      Purdue Industrial Waste Conference.

17 Steffen, A. J.  Stabilization Ponds for
      Meat Packing Wastes.  Journal Water
      Pollution Control Federation,  Vol. 35,
      No. 4,, pp 440-444.  April, 1963.

                                                    Anaerobic Industrial Waste Applications
18  Bhaskaran, T. R.,  and Chakrabarty,  R. N.
      Pilot Plant for Treatment of Cane-Sugar
      Wastes. Jour.  Water Poll. Control Fed.
      38.  7,  11SO.  July 1966.
19 Purice, V.  Methane-Production Fermenta-
      tion of Slurries in Residual Waters
      Effected in the Waste-Recovery Station
      of the Antibiotics Plant-Iasi. Chem. Abs.
      63, 2737.  1965.
                                                 This outline was prepared by J. C. Dietz,
                                                 Consultant,  Clark,  Dietz, and Associates,
                                                 Urbana, Illinois.


A  A previous outline by W. L. Carter described
   representative equipment for anaerobic
   digestion and related functions.  This out-
   line reviews some of the factors pertaining
   to operation of anaerobic digesters.

B  Anaerobic digestion is a biological process
   operating in the absence of dissolved oxygen
   in which sludge solids are partially degraded
   to form gaseous,  liquid, or solid residues
   of greater stability than that prior to

   1 The gaseous products include  methane,
     carbon dioxide and smaller proportions
     of other  components  some of which are
     highly malodorous.

   2 Liquid residues include ammonia,  free
     fatty acids,  soluble mineral or organic
     components formed in process as inter-
     mediates or in side reactions.  The
     liquid fraction  usually contains associated
     solids in a finely divided state.

   3 Solid residues  remaining characteristically
     are increased in stability and  disposability

     a  The more unstable components are
        likely to be part of the gas, or eluted
        from the solid residues in discharged

     b  Digested solids are likely to have a
        higher solids concentration and occupy
        less volume than before processing.

     c  Properly  digested sludge  solids are
        more  readily separated from remaining
        water; i.e., they are improved in
        drainability,  filterability  and driability.
II  Anaerobic digestion is a common process
 occurring wherever and whenever organic
 refuse accumulates to a point where dissolved
 oxygen penetration is insufficient to satisfy
 aerobic requirements.

 A Partial anaerobic digestion occurs in both
   natural and engineered facilities such as:

   1  Refuse dumps may  degrade via aerobic
      action at the surface but undergo
      anaerobic degradation in the interior if
      the  conditions,  amount  and nature of the
      refuse are suitable.

   2  Pooled areas (such as swamps, pot holes,
      impoundments) in surface  water may
      permit accumulation of benthic deposits,
      miscellaneous organic residues and
      other materials in amounts exceeding
      dissolved oxygen supply.

   3  Septic tanks, Imhoff tanks, cesspools,
      and natural or engineered basins for
      discharge of water  carried wastes of
      human activities generally are

   4  Engineered facilities such as those
      described previously including:

      a Conventional digesters

      b High rate digesters

      c Anaerobic contact processes

      d Anaerobic lagoons

 B Anaerobic degradation is limited by the
   biological,  chemical,  and physical factors
   common to natural processes.  Available
   energy,  temperature,  acid-alkalinity
   relationship,  mixing,  time,  and seeding
   are major variables controlling the
   progress of anaerobic digestion.
SE. AN. pp. 1.11. 68

 Factors Affecting Digester Efficiency
III  Control of digestion presupposes recog-
 nition of certain generalities involved in
 natural processes.  Waste treatment control
 depends upon selecting those conditions that
 enhance the probability that  a given operation
 will be  favored and maintained within
 acceptable limits for achieving acceptable

 A  Biological degradation includes aerobic
    and anaerobic processes  that  are so
    closely interrelated that it is  frequently
    difficult to distinguish among  them.

    1 Aerobic degradation is characterized by
      conditions in which dissolved oxygen
      is present in excess in the  water mass.

    2 Facultative degradation is  characterized
      by low  dissolved oxygen levels or by
      conditions that involve  alternate periods
      of dissolved oxygen excess or deficiency.

    3 Anaerobic degradation  is characterized
      by a gross deficiency of dissolved oxygen.
      Bound oxygen from sulfates,  carbonates
      or other sources must  be released in
      process to satisfy  the oxygen require-
      ments of the anaerobic system.

 B  Treatment operations involve all of the
    three stages of degradation listed under
    III A.

    1 III A  1 is predominant in terminal
      stabilization of wastewaters.  Ill  A   2
      is predominant in most wastewater
      treatment operations such as activated
      sludge, trickling filtration  or lagoons.
      Ill A  3 is predominant when organic
      solids degrade to acid  and  gas formation.

    2 It must be recognized that  sludges
      obtained from primary or secondary
      clarifiers are likely to be at some
      transition stage from III  A  2 to  3 before
      entering anaerobic digestion.  Control
      of operation includes techniques designed
      to smooth progress of  the transition.

 C  The input solids for anaerobic digestion
    include complex organic materials such
    as preformed proteinacious, fatty,   or
    carbohydrate residues from animal or
plant sources.  Cell mass,  of bacterial,
animal, or plant origin commonly is a
large fraction of the material to be digested.
It is usually associated with more inert
materials of organic or inorganic origin.

1 The preformed  material  of high
  molecular weight commonly undergoes
  enzymatic hydrolysis as  a first step in
  degradation; i.e. proteins are split to
  form peptides; the  peptides are degraded
  to amino acids; the amino acids are
  deaminated to form free  fatty acids and
2  The resulting free fatty acids may then
   be converted to methane and CC>  or
   other degradation products. Splitting
   and  gasification both are essential to
   the anaerobic process.

3  Hydrolytic splitting is common to
   aerobic and anaerobic degradation.
   More rapid cell growth  under aerobic
   conditions tends to resynthesize
   smaller molecules that  tend to  remain
   for later treatment after anaerobic

4  The splitting process (hydrolysis or
   acid formation) is  rapid compared to
   gasification and alkalinity formation in
   anaerobic digestion.  Digestion control
   includes holding sufficient older alkaline
   sludge to prevent  acidification  from
   predominating upon addition of  new feed.
   Digestion is unsatisfactory under acid

5  Maintenance of alkalinity is difficult to
   control because this  stage of digester
   operations is  characterized by  organisms
   that are readily upset by an unfavorable
   environment and have a low growth rate
   so that it requires extended time to
   reestablish an effective population after
   an upset.  Further, acid production
   occurs so readily and rapidly that there
   are  many opportunities  for production
   of a sour or malfunctioning digester.

                                                        Factors Affecting Digester Efficiency
IV  Section II  B listed several factors
 influencing digester operation efficiency.
 This section considers some of the more
 important control limits and techniques.

 A  Toxic  effects of mineral acids,  inorganic
    and organic toxic agents, may disrupt any
    biological system.   The alkaline or
    gasification stage of anaerobic digestion
    is more sensitive to toxic agents than most
    biological processes and requires longer
    time to recover from toxic effects.  Toxic
    limits of various materials are included
    in references too numerous to include

 B  Available energy contained in feed sludge
    must be sufficient to provide net energy
    for  metabolism and product formation after
    expenditure of energy for release of oxygen
    from sulfates,  carbonates, etc.  Anaerobic
    digestion conversions are limited to those
    for  high energy foods and tends to decrease
    in conversion efficiency as partial digestion

 C  Temperature has a two-fold effect upon
    digestion.  There appears to be a vaguely
    defined minimum temperature below which
    gasification is  limited severely and the
    temperature variation permissible within
    the  optimum temperature has narrow
    limits  to maintain consistant digestion.

    1 Septic or Imhoff tanks and unheated
      digesters maintain acid production and
      liquefaction  but commonly show a low
      rate gas production at temperatures of
      about 200 C (680 F) or less.   Very long
      detention time (6-12  mo.) may be
      required for conversion other than
      concentration of solids and elution of
      soluble or colloidal solids at the  lower

    2 Conventional digestion temperatures of
      250C to 350C (78QF to 95OF) favors
      good gasification in 20 to 30 days
      providing other conditions are acceptable.

    3 Higher digestion temperatures may
      favor more rapid conversion to gas,
      more complete gasification or more
      throughput per unit of volume.  The
     thermophillic range of digestion from
     490C to 560C (12QQF to 135OF) has
     had limited use for special effects or
     types of waste.  It is characterized by
     poor quality supernatants.

  4  Digestion  rate may be adversely
     affected by a temperature change of
     20 to 50C (40 to 90F).   Temperature
     changes that occur within 1 to 3 hours
     may disrupt operation, whereas the
     same absolute change over a period of
     1 to 3 days may not show noticeable
     effects. Addition of large  volumes of
     cold sludge  is a common cause of the
     rapid temperature changes during
     digestion (such as after an intensive

D Acid-alkalinity balance is interrelated
  with all major control variables and is a
  difficult but  essential control.

   1  pH control is an "after the fact" means
     of controlling digester operation.
     Acid-alkalinity balance has progressed
     too far by the time that a pH change

  2  New feeds tend to produce a release of
     acid products that must  be buffered or
     neutralized by alkalinity produced in
     later stages of digestion.  If a sufficient
     quantity of older sludge  is not present
     in the mixture, the digester becomes
     acid (or sour) and digestion fails.

  3  Withdrawal of too much  old sludge for
     disposal,  addition of excessive  quantities
     of fresh sludge, such as after a rain,
     chronic overloads, addition and
     retention  of low solids concentrations
     in the digester favor acid or sour

  4  Determination of volatile acids  and
     alkalinity in the digester are  essential
     for consistent control.   Experience
     shows that a volatile acid equivalent
     more than  1/2 of the alkalinity
     expressed as calcium carbonate calls
     for corrective action to  prevent upset.
     Buffer capacity diminishes rapidly with
     more acid conditions.

Factors Affecting Digester Efficiency
   5 Absolute values for acid or alkalinity
     are less important than the trend or
     change of values in process and the
     ratio of acid with respect to alkalinity.

   6 Conventional digestion operation
     commonly is considered effective at
     volatile acids below 2000 mg/1 and
     alkalinities of 3000 to 5000 mg/1.
     High acid content tends to reduce
     alkalinity which may result in unfavorable
     pH response when the acid content
     exceeds equivalent alkalinity.

   Seeding is an essential in digester startup
   and in maintaining digestion effectiveness
   from an organism and an acid-alkalinity

   1 Organisms capable of gasification are
     slow growing.  It would require 1 to 3
     months of  operation starting from a
     wastewater filled digester to accumulate
     enough old sludge to permit  conventional
     loading.  If the fresh feed is increased
     too rapidly,  acid production tends to
     exceed alkalinity available in the old
     sludge and the process fails.  Acid
     alkalinity balance must be carefully
     checked to estimate permissible loading.

   2 Addition of a significant volume
     (3000 to  10, 000 gallons) of concentrated
     solids from an established digester
     materially shortens startup time,
     accumulation of sludge solids, and
     permissible loading rates during

   3 Organisms are mainly associated with
     the sludge solids.  Supernatants or other
     low solids mixtures generally are not
     effective for seeding or alkalinity

   Mixing is one of the most common
   difficulties in digester operation.
   Effective gasification provides fairly good
   vertical mixing but mixing is most needed
   when gasification isn't proceeding normally
   such as after startup  or  upset.
1  Digestion tends to produce segregation
   of phases into a bottom sludge con-
   taining most of the active organisms,
   a scum zone at the top containing
   grease,  oils, and undigested solids
   more or less bound together by fibrous
   materials and a liquid fraction between
   the scum and solids zones.  The three
   layers must be mixed to achieve
   effective digestion.

2  Older  digestion units  commonly
   depended upon recirculation of
   supernatant in a  circular horizontal
   pattern with casual attention to vertical

3  Introduction of feed above scum levels,
   floating  covers to submerge scum, and
   bottom to top circulation helped
   digestion providing sufficient pump
   capacity and working  time was used.
   In many cases pump capacity was
   insufficient to circulate more than 1/2
   of the  contents of the  tank in any 24 hour
   period of continuous use. Obviously,
   this is not highly  effective mixing.

4  Gas recirculation appears to be gaining
   in popularity for improving  digester
   mixing and concurrent operating

5  Propellers in vertical draft tubes  also
   are effective until abrasion  destroys
   impeller efficiency.

6  Effective mixing can greatly extend
   capacity of any digester by insuring
   good contact of sludge and feed, con-
   trolling heat uniformity, and preventing
   local accumulation of scum, grit,  or
   grease.  Good mixing is an  essential
   for primary or high rate digesters.

Loading is closely related to acid-
alkalinity balance.  A new feed may  be
expected to result in a rapid rise in
digester  acidity. Good digestion will
continue  if there is enough old sludge
containing alkalinity to overbalance acid
production (assuming intimate mixing).

                                                 Factors Affecting Digester Efficiency
Precautions in adding new feed at frequent
intervals in small amounts helps to
maintain uniform operation and suitable
ratios of acid and alkalinity needed to
permit organism activity.

Rapid  changes in loading are to be
avoided if possible.   If unusual slug
discharges are unavoidable,  such as
following a rain,  it is advisable to
balance excessive amounts of new feed
with larger amounts of older  sludge
returned from secondary  digestion to
reduce the ratio of new volatile solids
added per unit of digester  volatile solids.

Conventional digestion usually means
addition of 2 to 4% new volatile solids
per day.   High rate digestion may
include from 5 to 20% of new solids per
day.  Some reports of higher loading
ratios are given.  The basic loading
criteria refers to a ratio  of new volatile
solids per unit of volatile solids already
present in the digester.

The common load criteria of pounds of
BOD per day is a convenient expression
of input related to volatile solids input
and assuming the presence of an adequate
amount of old solids to satisfy the load
ratio criteria  indicated in  IV  G 3.
   5 Detention time likewise is related to a
     load ratio  criteria,  i.e., 4% new solids
     per day implies that it will require
     about 25 days to replace the entire tank
     contents and that there was 24 days
     accumulation of old material in the tank.
     This is not strictly true as part of the
     volatile solids was removed as a  gas
     and part was  removed as eluate
     (supernatant) or waste sludge. Detention
     periods of as low as 3  1/2  days have
     been reported for high rate digestion
     (load ratios exceeding 0.2/1.0 VS
     basis).  Continuous vigorous mixing
     is essential to approach this type of
     operation.  Ten days is about the limit
     for applied use.

   6 It is imperative that some acceptable
     ratio of new solids to pre-existing
     digester solids be maintained, however
     it is expressed.  Gross old sludge
     removal or new sludge addition tend to
     upset the acceptable ratio found for a
     given operation.


This outline contains certain materials
available from previous outlines by
J. C. Dietz and L. T.  Hagerty.

 This outline was prepared by F. J.  Ludzack,
 Chemist, National Training Center, FWQA
 Cincinnati,  OH  45226.

                                   AEROBIC DIGESTION

 The digestion process,  that is the decom-
 position of organic matter to a non-putrescible
 and  inoffensive state, can occur under either
 anaerobic or aerobic conditions.  It is the
 purpose of this discussion to present the
 general concepts and to briefly outline the
 various aerobic digestion methods.
                     R— C —J


                                R	C

 In aerobic digestion, complex organic materials
 such as fats, proteins, and carbohydrates are
 decomposed to form simpler products.

 The products of hydrolysis and oxidation
 resulting from aerobic digestion, and the
 cyclic nature of the component elements
 (carbon, nitrogen, and sulfur) are shown in
 Figure 1.  Comparison with the  cycle for
 anaerobic digestion (Figure 2) reveals signif-
 icant differences in the nature of the
 decomposition products.

 Oxidation is defined as the removal of hydrogen,
 addition of oxygen, or other reaction making
 the oxidized item more electropositive.  The
 removal of hydrogen is a common first  step in
 decomposition of organic matter as illustrated.

    f H~ ~H~t

  R—C	C—H

      I    I
     H  H
                  The hydrogen atoms removed combine with
                  oxygen, carbon, nitrogen, or sulfur.
                  Aerobic bacteria utilize oxygen as the
                  hydrogen acceptor.  Anaerobic bacteria use
                  "chemically bound oxygen, " carbon,  nitrogen,
                  or sulfur as the hydrogen acceptor.
                  Facultative bacteria may use both of these
                  but in any case will use the hydrogen acceptor
                  yielding the most energy.

                  Hydrogen  removal follows a definite pattern
                  and is brought about by the coenzymes DPN
                  or TPN.   DPN and TPN take up one hydrogen
                  ion and two electrons leaving one free
                  hydrogen ion.
                  In aerobic microorganisms,
                  (FAD).  The reaction being;
                            DPN H  is
 regenerated by flavin adenosine dinucleotide
                     DPNH  + FAD
                        DPN + FADH,,
                  FADH  is regenerated with oxygen to form
      /  i
     OJH \


 It is necessary to have a supply of the proper
 types of microorganisms, suitable food
 materials, an oxygen source, and an environ-
 ment conducive to growth and reproduction.

 A Microorganisms

    Decomposition of organic waste requires
    a community consisting of many kinds of

Aerobic Digestion
                                        1. Nitrogenous
                                        2. Carbonaceous
                                        3. Sulfurous
                                                                       Products of
                                                                     1. Ammonia
                                                                        Carbon dioxide
                                                                     3- Hydrogen
Animal Matter
                                         Reservoir of
                                      Oxygen, Nitrogen
                                      and Carbon dioxide
                                      in Air and Water
                                                 biological oxidation •
                                                                     Products of
 Living Plant
                                                           1. Nitrite nitrogen
                                                           2. Carbon dioxide
                                         Products of
                                      1. Nitrate
                                      2. Carbon dioxide
                                      3. Sulfates
          FIGURE 1. Cycle of nitrogen, carbon, and sulfur in aerobic decomposition.

                                                               Aerobic Digestion
                                                             Products of
                                                         1.  and 2. Organic
                                                         acids,  acid carbon-
                                                          tes, and carbon
                                                             3.  Hydrogen
Animal Matter
                              of Oxygen,
                             Nitrogen and
                            Carbon Dioxide in
                             Air and Water
                                                            Products  of
                                                          . and 2. Ammonia
                                                          itrogen, acid
                                                         .carbonates, and
                                                           carbon dioxide
                                                              3.  Sulfides
   Living Plant
                              Products of
                            and 2. Ammonia
                          nitrogen, humus,
                          carbon dioxide,  and
                             3. Sulfides
FIGURE 2.  Cycle of nitrogen, carbon, and sulfur in anaerobic decomposition

Aerobic Digestion
   1  Bacteria

   2  Molds

   3  Yeasts

   4  Algae

   5  Protozoa

   6  Rotifera

   7  Worm and insect larvae

B  Food Materials

   Nearly all organic wastes may serve as
   food supply for the community.  Some
   exceptions may be organic pesticides,
   hydrocarbons,  and ethers.  It has been
   shown, however, that even highly toxic
   materials,  such as phenols,  can be used
   as food if the community is acclimated to
   the waste.
C  Oxygen Source

   The oxygen source is generally the
   atmosphere but the method of introducing
   this oxygen into the waste  stream will
   vary,  depending upon the method of

   The oxygen budget (Figure 3) illustrates
   the factors which  affect the dissolved
   oxygen concentration in a water mass.
   In the case of aerobic digestion of organic
   wastes,  reaeration is the most significant
   means of supplying the required oxygen.

   In natural streams, lakes, ponds, and
   bays photosynthesis can  become a
   significant source of  dissolved oxygen
   during daylight hours.

D  The Environment

   Important environmental factors include:
   temperature,  pH,  organic waste concen-
   tration,  presence of toxic  substances, and
   Substrate for biological growth.
                                         FIGURE  3
                                                       LOSS FROM
                                            B.O. D.
                                                  DIFFUSION INTO
                                                 BOTTOM MUDS
                                   DISSOLVED OXYGEN
                                         OF A
                                     WATER MASS

                                                                          Aerobic Digestion
    1  Temperature has an effect on the rate
       of biological activity as well as being
       a determining factor in the types of
       organisms which will thrive.   The
       range at which mesophilic microorganisms
       thrive is up to HOOF; the thermophilic
       range extends above llOop with optimum
       activity at 13QOF. Activity decreases
       rapidly below about 10°C but is detectable
       at 1
Aerobic Digestion
   In aerobic digestion, the predominate
   hydrogen acceptor is oxygen, with nitrogen,
   carbon, and sulfur proceeding to form
   NO"  CO , and SO  = during decomposition
   of organic matter.  Hydrogen acceptors
   during anaerobic degradation include carbon
   to form methane and oxygen to form water.

   A suitable environment must be  provided to
   stimulate the growth and reproduction of
   a biological community.  Such an environ-
   ment may be provided  for treatment of
   organic wastes in:

   1 A trickling filter

   2 Activated sludge

   3  Stabilization ponds
   Fair,  G. M. and Geyer,  J. C.,  Water
     Supply and Waste-Water Disposal,
     John Wiley & Sons, New York, (1966).

   Gurnham,  C.F., Principles of Industrial
     Waste Treatment,  John Wiley & Sons,
     New York, (1955).

   McKinney, R.E.,  Microbiology for
     Sanitary Engineers,  McGraw-Hill,
     New York, (1962).

   Rich,  L. G., Unit  Processes of Sanitary
     Engineering, John Wiley  &  Sons,
     New York, (1963).

1  Babbitt, H.E.,  Sewerage and Sewage
      Treatment, John Wiley & Sons, New York,
This outline was prepared by L. J. Nielson,
Sanitary Engineer,  FWQA  Training
Activities, PNWL.

                             VARIATIONS AND MODIFICATIONS

A  In practice there are three ranges of food-
   to-microorganism (F/M) ratios where the
   resultant activated sludge physical quality
   permit successful continuous plant operation
   with a minimum of problems.  The higher
   loading range is designated high rate, the
   intermediate range is conventional, and
   the  lowest loading range is extended
   aeration.  The fourth basic process
   variation does not require sludge  separation
   for  recycle.  It operates  at the highest
   loading range and is designated dispersed
   growth.   The characteristics of these
   process variations are shown graphically
   in Figure 1.

B  While there are four basic process variations
   to be considered in activated sludge waste
   treatment,  there are many modifications
   that have been adapted by the design
   engineer since the first activated  sludge
   waste treatment plant was constructed in
   the United States about 1920.  The purpose
   of this outline will be to consider  these
   major modifications and their  advantages
   or limitations.

  When true log growth occurs,  the number of
  organisms should double in size every 20 -
  60 minutes.  This may occur with food levels
  of 1, 000 -  10, 000 mg/1 as in bacterial
  culture work.  In most waste treatment
  plants,  however, typical air supply and
  nutriment levels do not support log growth
  very long and usually for a small percentage
  of the organism population.

  Dispersed growth,  therefore,  is a basic
  process variant which is primarily of
  academic interest.  In the presence of a
  large excess of soluble organic food matter,
  the microorganisms operate at high energy
  levels in assimilating this food matter.
  Settleable suspended solids are not removed
  from the effluent and returned to aeration for
  reuse.  New cellular matter is formed as
  fast as it is lost with the effluent.  A low
  solids equilibrium can be maintained without
  the need for return  of sludge.
                    .log  Growth Declining
Endogencous Phase

                                                 Food Remaining Unstabilized
                          PICUR£ 1   Ideal Growth Curve — Continuous Operation

 Activated Sludge Waste Treatment Process Variations and Modifications
  The dispersed growth activated sludge
  treatment process utilizes the simple flow
  arrangement shown in Figure 2.  Note that
  final clarification of the effluent is omitted.

  Because of the low BOD  removal and high
  loss of cellular matter  in the effluent, the
  dispersed growth process has limited use.
  Primary use is for relief of loading for
  subsequent treatment.
 The high rate process operates at high BOD
 loadings or food-to-microorganisms ratios
 and has a high cell synthesis rate resulting in
 maximum production of excess sludge. This
 generally amounts to about 0.75 pound of  sludge
 produced for every pound of BOD reduced by
 the process.  The high rate process also  has
 the smallest overall oxygen requirement which
 is approximately 0. 45 pounds of oxygen per
 pound of BOD reduced.
Only a small amount of sludge is recycled to
the aeration tank,  and the aeration period is
kept short.  The fraction of oxidizable organic
matter removed is in the range of 60 - 70
percent.   The process uses a minimum of
aeration volume,  oxygen and aeration power
for the load treated.  While the system
upsets easily, it returns to usual operating
efficiency quickly.  Sludge produced usually
settles and compacts  readily.

Aside from lower  BOD removal,  its biggest
limitations are from high waste  sludge pro-
duction which requires large digestion
facilities and results  in high sludge disposal

A  High Rate or Modified Activated Sludge

   High rate or modified activated sludge
   treatment utilizes  the simple aeration
   tank-final clarifier arrangement which is
   also standard for conventional treatment.
   This is shown in Figure 3 below:
Raw Waste v


•ludge to Digester
Aeration .-^
Tank trfL-^
                                                                          Waters .
                                FIGURE 2  DISPERSED GROWTH
Waste v


Sludge 1 to g
Y Digester 3
Excess Sludge
* r

Aeration «— «v
— . Tank v^

Return & Excess
                              FIGURE 3   High Rate or Modified Aeration

                Activated Sludge Waste Treatment Process Variations and Modifications
   The step loading method of feeding has
   also been employed with this flowsheet.
   Primary treatment may be included as
   shown, or it can be eliminated from the
   flowsheet if desired.

B  Supra-Activation

   Supra-activation is a high-load process
   modification giving a degree of treatment
   similar to that achieved by modified
   aeration and using the same structures.
   It may be used for "roughing" treatment
   preceding other processes.  Patent
   applications have been made by W. H.  Torpey
   for this process with assignment of the
   rights to Chicago Pump.  The principal
   advantage of this variation is that for  tank
   loadings of 200 to 800 pounds of  BOD  per
   1000 cubic feet of aeration tank capacity,
                    the aeration tank required is approximately
                    one-quarter of the size of that required
                    for the Modified Aeration process and
                    approximately one-eleventh of the size
                    required for the Conventional Activated
                    Sludge process.

                  C Activated Aeration

                    Figure 4 below  shows a modification of the
                    High Rate process that is referred to as
                    activated aeration.

                    Activated aeration is capable of providing
                    an effluent of intermediate quality at 25%
                    savings in air compression power costs
                    when compared with the  straight high rate
                    process.  The difficulties of control
                    experienced with high rate treatment are
                    avoided since it is not necessary to recycle
                    active solids through the system.  Some
                    reductions in sludge production are also
          Raw Waste

                            Return & Excess Sludge

           Raw Waste



                                                          Sludge to Thickener
                                                            and/or Digester
                           FIGURE  A  Activated Aeration

 Activated Sludge Waste Treatment Process Variations and Modifications

 Conventional operation is the oldest and most
 commonly used mode of the activated sludge
 treatment.  It is versatile and represents a
 good compromise among treatment performance,
 capital, operating and sludge disposal costs
 for plants of the household variety to the
 large city plant.  Economics and operational
 control are  favored in the large plant facility.
 Effluent quality will satisfy  most government
 standards.  Additional solids, nitrogen, and
 phosphorus  removal may be required in
 critical situations.   Some tradeoff is possible
 between aeration and sludge disposal cost -
 more aeration, less net sludge residual.

 Any biological process performs better at
 uniform low loading,  non-toxic environment
 and favorable conditions.  Operating control
 requirements rapidly rise as these criteria
 depart from the ideal due to design, capacity
 or loading factors.   It is a cause and effect
 situation. High performance expectancy for
 a natural process compressed in terms of
 time and space requires more operational
A  Conventional Plug-Flow Activated Sludge

   The original standard flowsheet uses what
   we now call plug-flow aeration tank design.
   These tanks  were long rectangular basins
   with the waste introduced at one end and
   discharged at the opposite end some
   distance away.

   Figure 5 shows a common version of this
   modification using series, multi-pass,
   aeration with return sludge and influent
   introduced at the tank inlet.

   It was believed that this flow arrangement
   was very desirable  since it reduced short
   circuiting to a minimum, insuring that all
   of the waste  remains under aeration for
   the maximum peribd of time.

   On the other hand,  this kind of flow pattern
   produces a continually changing environ-
   ment within the aeration tank.  During
   passage, the available food is being used
   up while the  population of microorganisms
   at first increases and then decreases.
   Under these  conditions,  there is a situation
   of constantly varying food/microorganism
   ratio.  The BOD  loading is high at the
   head end of the aeration basin and low at
   the effluent end with an average loading
   occurring only briefly somewhere during

Waste ^


udge 1 to Digester
Excess Sludge
Aeration — ^
^-, Tank ^S


Return & Excess Sludge
                        FIGURE 5  Conventional  Plug-Flow Activated Sludge

                   Activated Sludge Waste Treatment Process Variations and Modifications
Since loading is continually changing, the
environment is forever changing and the
relative predominance of the various species
of microorganisms continuously change.
Equilibrium is never obtained and the
system is always out of balance.  Under
these conditions, the microorganisms work
less efficiently than if they are provided
with a constant environment.

1  Characteristics

   a  Detention time in aeration tank --
      4 to 8 hours.

   b  Loading -- 25 to 35 Ibs BOD  per day
      per 1000 cu.  ft.  of aeration tank
      capacity, or 0. 2 to 0. 5 pounds BOD
      per pound of volatile suspended
      solids (VSS) under aeration.

   c  Return sludge rate -- return sludge
      ratios for this type of system usually
      maintained between 25 to 50  percent.
      As the loading increases,  solids
      return should increase.

   d  Air introduced uniformly along tank

   e  Highest organic loading and hence
      highest oxygen demand at head of
      aeration tank.
      f  Waste stabilization proceeds along
        length of tank -- hence lowest oxygen
        demand at outlet end of tank.

      g  Excess sludge production - for
        systems treating domestic wastewater,
        the volume of excess sludge to be
        disposed of is usually about 1. 5
        percent of the influent flow or about
        0.5 Ibs/lb BOD  removed.

      h  Most process modifications were
        adapted to improve conditions to
        make better use of biological
        stabilization in available space and

B  Tapered Aeration Activated Sludge

   A relatively high initial oxygen demand is
   normally encountered at the influent end
   of the aeration tank of a conventional
   activated sludge treatment  plant.  As the
   flow passes down the length of a tank, the
   oxygen demand  of the waste is gradually
   satisfied and the remaining oxygen demand
   becomes less and less.

   The Tapered Aeration process shown in
   Figure  6 is designed to supply more oxygen
   at the head end of the system where the
   load is  highest and then reduce it pro-
   portionally with the organic loading along
   the length of the  aeration tank.
                                       AIR IN
Tu 4rTT**
ill i i i \
4*it i 1 V tl
^ 1 4 I i

                               FIGURE 6 TAPERED  AERATION

Activated Sludge Waste Treatment Process Variations and Modifications
   1  Flow diagram same as Conventional.

   2  More air introduced at the inlet end of
      the aerator than in subsequent aerator

   3  Results in more efficient use of air and
      improved aeration power economy.

   4  Detention times and loadings  similar to
      conventional system -- Tapered
      Aeration has a volumetric loading of
      about 35 pounds BOD  per day per
      1000 cubic feet of aeration tank capacity.

C  Step-Aeration Activated Sludge

   Another way to even  out the oxygen demand
   in the  mixed liquor of the aeration tank is
   to introduce the waste flow at intervals
   throughout the length of the tank. This
   process is termed Step Aeration but might
   more correctly be termed Step  Loading.
   This system is shown in Figure  7.
If the aerator happened to be divided into
four passes,  the return sludge usually
would be introduced at the inlet of the first
pass and flowing through the rest of the
passes in series.  Sewage may be added
in any desired portion at the head end of
any or all of  the passes.  Ordinarily,
one-quarter of the primary  sewage effluent
flow is admitted to Pass  B,  one-half to
Pass C and one-quarter to Pass D.  The
net  result is  a better  mixed system with
more equalization of the  load.  The
advantages claimed for this method of
waste loading are:  higher BOD,, removal
with shorter  detention time, good sludge
settling with  uniform  degree of treatment
and more efficient oxygen transfer.  This
modification  is  particularly good for waste-
waters with high organic loadings
providing solids transfer is good.  The
benefits gained are  those obtained in the
use of a more completely mixed conventional
system with the following characteristics:

1  Sewage introduced at various points
   along length of aeration tank.
                   EXCESS SLUDGE
                                        RETURN & EXCESS SLUDGE
f 	 <



1 1 TANK
J *—



                    Activated Sludge Waste Treatment Process Variations and Modifications
   2  Evens out organic load and also oxygen

   3  Detention time in aeration tank --
      3 to 4 hours.

   4  Loading -- 50 to 75 Ibs BOD  per day
      per 1000 cu.  ft.  of aeration tank.

   5  Return sludge ratio -- 25 to 50%.

D  Complete - Mix  Activated Sludge

   Aeration systems which approach  complete
   mixing are easily obtained by the proper
   choice of aeration tank shape,  method of
   feeding, and aeration equipment.  Figure
   8 below shows one possible arrangement.
   This is more readily obtained in small

   Greater dispersal of the  influent and more
   rapid mixing with the tank contents is
   desired.   Single  or  multiple point  feed and
   discharge can be used depending on the
   size and type aeration system provided.

   Mechanical aerators, are significantly
   different from diffusion devices  in two
   respects. First, they produce a higher
   degree of mixing intensity and,  second,
   they mix in all directions.  The  flow
   pattern due to mixing is not only perpen-
   dicular to the direction of process flow
   but also in the same direction and against
   it.  More complete  mixing is likely as
   compared to conventional diffused air
   1  Incoming sewage and return sludge
      are completely and instantaneously
      mixed with the aeration tank contents.

   2  Results in uniform environment that
      allows much higher loadings and
      shorter detention times than with any
      other modification.

   3  More likely to dilute shock loads.

   4  Loading distributed among entire tank
      contents; better adapted to high load

   5  Return sludge ratio - return sludge
      ratios should be as high as necessary
      considering sludge characteristics
      and loading.

E  Contact Stabilization

   Contact Stabilization uses two separate
   aeration tanks to provide two stage sludge
   aeration.  The principle is to use first
   a short (0.5 - 1.0 hour) "contact" stage,
   during which a major fraction of the applied
   BOD  is transferred from the wastewater
   to the sludge solids. This occurs by
   adsorption,  absorption, mechanical
   entrapment, assimilation, filtration, etc.
   The sludge is then separated from the
   treated liquid in a clarification step.
   The sludge moves to a "sludge reaeration"
   tank with a detention time of 4 - 8 hours,
   which allows the sludge stabilization to
   continue.  This process is attractive when
   used on wastewaters containing high
   proportions  of particulate materials such
   as domestic waste.


ludge to Digester
Excess Sludge
Complete - Mix
Return Sludge


j Return & Excess Sludge \

                        FIGURE 8  Complete - Mix Activated Sludge

Activated Sludge Waste Treatment Process Variations and Modifications
   The process may be operated to give
   excellent treatment with low net sludge
   production.  The provision for discharge
   of the effluent after short period aeration
   with continued aeration of the more
   concentrated activated sludge means that
   total tankage for aeration may be reduced
   as much as 50% below that for conventional
   processing.   Wastewaters containing
   predominantly soluble components may
   not be transferred to the solids phase rapidly
   enough for good treatment.   The contact
   process tends to recover more rapidly
   from shock loads.

   It is often possible to operate an over-
   loaded Conventional Activated Sludge
   system as a Contact Stabilization system
   by changing to step feed and  adding the
   feed later during aeration.  Redesigning
   may only involve changes in the plant
   piping or relatively minor modification
   to the aeration tank layout.   The settling
   unit capacity,  of course, would have to
   be increased as flows approach or exceed
   the original design values.
1  Process modification depends on
   ability of activated sludge to trap
   colloidal and suspended organic matter.

2  Works best with wastes high in colloidal
   organic matter.

3  Reaeration carried out only on settled
   sludge volume.

4  Detention time in initial aeration tank--
   0. 5 to  1 hour.

5  Detention period in reaeration tank --
   4 to 8 hours.
6  Loading -- 35 to 70 Ibs, BOD per day
   per 1000 cu.  ft.  of combined aeration
   tank volume.








, 9

f :





                            FIGURE 9  CONTACT  STABILIZATION

                      Activated Sludge Waste Treatment Process Variations and Modifications

 The extended aeration process represented
 by the two modifications shown in Figures
 10 and 11 is  designed for low loading as com-
 pared with previously discussed activated
 sludge operating modes.  It has also been
 referred to as the total or complete oxidation
 process. Solids digestion does limit net
 sludge production but does not eliminate it.
 Extended aeration typically operates at very
 low food-to-microorganism ratios and
 produces a minimum of  residual  products.
 About 0.15 pound of excess sludge is produced
 for each pound of BOD,, reduced.

 Minimum sludge production is not obtained
 without penalty.  There is maximum oxidation
 of organic matter to the ultimate end products
 of carbon-dioxide and water with high power
 requirements for. supplying that oxygen.  As
 loading decreases, more oxygen is used for
 sludge stabilization.
      The unit rate of oxygen utilization,  oxygen
      uptake rate, usually decreases so that a long
      aeration time is required.

      In theory, the rate of sludge build-up is
      balanced in the extended aeration process
      by the rate of sludge destruction.  The process
      can be operated in a balanced state,  but the
      ultimate plant effluent discharge quality will
      be lowered with the loss of incompletely
      digested solids via the effluent.

      Where a plant is fully loaded and a highly
      polished effluent is required, it will be
      necessary that excess sludge be wasted at
      intervals of one to two weeks.  The surplus
      sludge may be discharged without offensive
      odors, for direct  drying on open drying beds,
      worked into soils  or may be diverted to a
      sludge storage tank and accumulated for
      ultimate disposal  on restricted areas.  Cold
      weather operation usually shows poor sludge
      stabilization and settling.  Generous holding
      tankage is required.
                RAW WASTE
                              RETURN SLUDGE

Activated Sludge Waste Treatment Process Variations and Modifications
     Brush -
                         FIGURE  11  Extended Aeration Oxidation Ditch
      Usually smaller package type plants.
      Economics limit these to relatively
      small sizes (up to 0.5 mgd capacity).
      Used for small communities, trailer
      courts,  motels,  etc.

      Long aeration period (24 hours) results
      in aerobic digestion of solids.

      Designed for  no sludge wasting, but  will
      always have slow buildup of inert solids
      that will be lost in effluent.  Some
      sludge control and wastage is necessary
      to obtain high quality effluents.

      While screening is desirable,  primary
      sedimentation may be omitted.

      Sludge disposal costs are relatively  low;
      but large aeration volume and aeration
      power requirements are encountered.

      Extended aeration may require more
      than double the unit oxygen requirement
      of the conventional process.  As much
      as 1. 8 pound  oxygen per pound  BOD
      reduced may  be used by extended
      aeration while process with separate
      solids removal may use about 0.4-0.8
      pound oxygen  per pound BOD  reduced.
       High effluent nitrification causes
       frequent problems with the final
       clarification especially when scum
       control is omitted on the final clarifier.

 Many of the activated sludge waste treatment
 process modifications discussed in this
 outline are not really separate processes in
 themselves,  but are  actually operational
 modes of the same thing.  The major differ-
 ences between them involve variations in
 waste  loadings, food-to-microorganisms
 ratios and in-plant flow patterns.  Most
 waste treatment plants are hybrids of two
 or more of the process modifications dis-
 cussed.   Good design practices provide the
 operator with the capability to change plant
 operational characteristics as may be
 advantageous depending on influent nature
 concentration and flow pattern.

 Table  1,  which follows,  lists the typical
 operational characteristics and design
 criteria for the major activated sludge
 waste treatment modifications considered
 in this outline.

Name of
Modified or
"High Rate"
Step -
MGD- Plant
Design Flow
To 0.5
0.5 - 1.5
1.5 up
To 0.5
0.5 - 1.5
1.5 up
0.5 - 1.5
1.5 up
To 0.5
0.5 - 1.5
1.5 up
To 0.05
0.05-0. 15
0. 15 up
Plant Design
To 1000
1000 - 3000
3000 up
2000 up
1000 - 3000
3000 up
To 1000
1000 - 3000
3000 up
(Ibs BOD5
per day
per 1000
cu. ft.)
30 - 40
30 - 50
30 - 50
Period In
(based on
design flow)
7.5 - 6.0
2.5 up
7.5 - 5.0
3.0 - 2.0
1.5 - 2.0
Min. Air
cu. ft.
400 - 1500
2/1 to 4/1
1/1 (or less)
2/1 to 5/1
2/1 to 5/1
10/1 to 20/1
Return Sludge
Rate - (percent
of design flow)
15 - 75
Ave. 30
Ave. 20
20 - 75
Ave. 50
50 - 150
Ave. 100
50 - 200
Ave. 100
Period Final
Settling Tanks
95 +
60 - 75
90 - 95
85 - 90
75 - 85
             *Aeration Period in Contact Zone which represents 30 - 35 percent of the total aeration capacity.






Activated Sludge Waste Treatment Process Variations and Modifications
Table 2 groups the activated sludge process
modifications according to waste loadings.
                 TABLE 1

1.  High Rate AS Process Variations

    (Waste Loading > 1. 0 Ibs COD/lb MLVSS/day

    Dispersed Growth
    High Rate
    Modified Aeration
    Supra Activation
    Activated Aeration

                           1  Eckenfelder, W.W., Jr.  Biological
                                Conversion Process, Unpublished paper
                                prepared for FWQA manual on sewage
                                treatment processes.   1969.

                           2  Lesperance,  T. W.   A Generalized
                                Approach to Activated Sludge, Parts
                                1-7, Waterworks and Wastes Engineering,
                                Ruben Donnelly Publishers, New York.
                                April-October 1965.

                           3  Stewart, M. J.   Activated Sludge Process
                                Variations -- The Complete Spectrum,
                                Water and Sewage Works,  Pages R-241
                                through R-262,  Reference Number.  1964.
2.  Conventional AS Process Variations
    (Waste Loading
0.2 to 1.0 Ibs COD/lb
    Complete Mix
    Plug Flow
    Tapered Aeration
    Step Aeration
    Contact Stabilization

3.  (Waste Loading < 0. 2 Ib COD/lb MLVSS day)

    Extended Aeration
    Oxidation Ditch
                           This outline was prepared by James A.
                           Montgomery,  Sanitary Engineer,  River
                           Basin Planning, OWP, Washington, DC 20242.

                                 AVAILABLE SECONDARY TREATMENT PROCESSES

 A Pollution can be greatly reduced, almost
   overnight, by maximum use of existing
   secondary treatment processes.

 B Activated sludge plants can produce final
   effluents containing considerably less than
   10 mg/1 suspended solids and 5-day BOD.
   Overall reductions of 95 to 99 percent are

   To obtain such results; the plants must be
   properly designed with adequate  built in
   capacity and flexibility; plant characteristics
   must be appropriate to the incoming  load;
   and the process must be skillfully controlled
   by conscientious qualified operators.

A Plant Description

   Treats 3.5 mgd strong meat-packing waste
   and 6.0 mgd domestic sewage.  High rate
   trickling filters pre-treat packing plant
   wastes; activated sludge treats domestic
   sewage and polishes industrial wastes.

B Feature Story - 99% Reductions

   Has demonstrated ability to provide 99%
   reductions during summertime (August)
   when plant was operating within design
   loading (Figures 1 and 2). BOD reduced
   from 900 to 9; TSS from 650 to 5 (Figures 3
   and 4).

C Improved Operational Control

   Wintertime pollutional load to river cut in
   half by improved operational  control alone.
   1  Control tests

     Started using:
       Settlometers for sludge density

       Centrifuge for sludge density

       Blanket finder for clarifier sludge
       Turbidimeter for current effluent

   2  Interpretation

     Sludge condition, system equilibrium,
     and process demands are the key items
     for system control.

   3  Control adjustments

     a  Increased return sludge percentage
        from 30% to more than 100%.

     b  "Tight-rope" sludge wasting control
        to increase sludge concentration and
        activity without upsetting aerators
        and clarifiers.

   4  Improved effluent quality

     Former 30 mg/1 BOD  reduced to 20 mg/1
     Former 35 mg/1 TSS reduced to 13 mg/1

D  Significant Loading Characteristics

   See Table No.  1.

E  Favorable Features at the Existing Plant:

   1  Dedicated supervision and operation

   2  Efficient aerators (Not spiral flow)

   3  Effective suction type  final clarifier
     sludge removal  mechanism
 PC. WAS.9.1.69

Effluent Excellence from Secondary Treatment Processes
         Of 90
  (AUG.& DEC.,1967)
                        1         10          50         90
                              % OF TIME EQUAL TO OR LESS THAN
                                                       SIOUX FALLS, S.D.
                                               SUSPENDED SOLIDS REDUCTIONS
                                                   THROUGH ENTIRE PLANT
                                                     (AUG. A DEC., 1967)
                                            50            90
                             % OF TIME EQUAL TO OR LESS THAN

                              Effluent Excellence from Secondary Treatment Processes
     U so
     tt 40
     (Q 30
        0.001  0.1
                              10   20    40    60        90
                          % OF TIME EQUAL TO OR LESS THAN
-t  30
<  20
          FIGURE  4
     001    0.1
                             10   20    40    60     80   90
                       % OF TIME EQUAL TO OR LESS THAN

Effluent Excellence from Secondary Treatment Processes
                                    TABLE NO.  1

                    (Sioux Falls, South Dakota - Activated Sludge Plant)

                                                          SUMMER   WINTER
             BOD Load to Aerators

               Pounds per day                               18, 000       37, 400
               Pounds per 1,000 cu. ft. Aerator                 103          160
               Pounds per pound mixed liquor solids             1.3          1.2

             Clarifier Surface Loading Rate

               Gals./sq.ft./day                                720          640

             BOD Reductions

               Total - Trickling filter &  activated sludge        99           97
               Activated sludge alone                           95           90

             TSS Reductions

               Total - Trickling filter &.  activated sludge        99           96
               Activated sludge alone                           96           83

             Air (Approximate Range)

               12 to 36 million cu.ft./day
               0.5 to  3.0 cu.ft. /gal.
               300-1,000 cu.ft./lb.BOD

             Return Sludge - 30% to 200%

             Aeration Detention Time - 1. 5 to 3.0 hr.
   4 Complete mixed aerator flow pattern            5 No scum removers on final clarifiers

   5 Adequate return sludge pumping capacity        6 Impossible to make precise control
                                                      adjustments.  (Not enough meters, no
F  Plant Deficiencies                                  remotely controlled mechanical valve
                                                      actuaters,  and no automatic sensor-
   1 Activated sludge plant overloaded                 controllers. )

   2 Trickling filters freeze up in winter
                                                III  METROPOLITAN ST. LOUIS SEWER
   3 Disproportionately small aerator/               DISTRICT - MSD
     clarifier volume
                                                    Coldwater Creek Wastewater Treatment
   4 Not enough air                                 Plant (Activated Sludge)
                                                 A  Basically, this  is a conventional 21 mgd
                                                    standard rate activated sludge plant.


                                      Effluent Excellence from Secondary Treatment Processes
      There are 6 aerators with spiral flow
      pattern diffusers and 4 final clarifiers
      with plow-type sludge scrapers.

   B  Feature Story -  Pollution reduced to 1/4
      its former strength by operation control
                                  Before  After
      1 Suspended Solids

        Raw               (mg/1)    173     198
        Primary Effluent   (mg/1)    155     142
        Final Effluent      (mg/1)    9j2      _16
        Activated Sludge Reduction   40%    89%
        Total Plant Reduction       46%    92%
      2 5-Day BOD

        Raw              (mg/1)   150     162
        Primary Effluent  (mg/1)   152     130
        Final Effluent     (mg/1)    40      _9
        Activated Sludge Reduction   74%    93%
        Total Plant Reduction        73%    94%

   D  Improved Operational Control

      1 Changed aerator/clarifier ratio:  - by
        taking one of the 4 clarifiers out  of
        service and placing an additional aerator
        in  service.  Theoretical full load
        characteristics as follows:
Aerator/Clarifier Combination
Mixed Liquor (% by Centrifuge)
Return Sludge (% of Sewage Flow)
Flow Capacity (MGD)
Aerator Detention (HRS)
Clarifier Detention .(HRS)


      2  Control Tests &. Interpretation
        Introduced use of settlometers,  centrifuge,
        blanket finder and turbidimeter to detect
        process balance and demands.

      3  Control Adjustments

        In this case:  Reduced return sludge
                     pumping.  Increased air
                     supply and excess sludge-
                     wasting rates.
 E Favorable Features at the Existing Plant

    1  Dedicated supervision and operation

    2  Adequate plant capacity for present dry
       weather flow

    3  Multiple unit aerator and clarifier groups

 F Plant Deficiencies

    1  Plow-type sludge scrapers in final

    2  Spiral flow diffuser placement in

    3  Hydraulic short circuiting plus strong
       velocity currents in final clarifiers

    4  No scum  removal for final clarifiers

    5  Inadequate return sludge capacity

    6  Meter problems,  and lack of remotely
       controlled mechanical valve actuators
       or automatic sensor-controllers limit
       process controlability.

 G Present Status

    1  Presently obtaining 90% reductions

    2  Could cut pollutional load in half again
       if obvious plant deficiencies were


 A The activated sludge process can produce
    sparkling clear final effluents.

    Plants can and should be properly designed
    (or modified) and operated to obtain their
    maximum inherent purification efficiencies
    needed to abate pollution of our national
    water resources.  These include:

 B Design

    1  Provide adequate capacity for  growth
       and equipment outages.

    2  Flexibility - (Give the operators a

Effluent Excellence from Secondary Treatment Processes
     Provide ability to increase or decrease
     number of aerators or clarifiers, convert
     to a complete mixed system or to step
     aeration as required.

   3  Avoid "spiral flow" aeration.

   4  Use suction devices in final clarifiers
     for rapid  removal of fresh sludge.
     Also provide surface  scum removers.

   5  .Make air  supply, sludge return and
     sludge wasting equipment truly variable
     and conveniently controllable.

   6  Provide essential meters and sensors,
     remote valve actuators and automatic
     ratio  controllers where required.
C  Operation

   1 Recruit and retain conscientious,
     intelligent,  trained, and certified
     plant operators.

   2 Provide practical "on-the-job" work
     experience type training.

   3 Provide 24-hour around-the-clock
     operation.  Test,  evaluate and adjust
     process at least once per 8-hour shift.

   4 Make the  best use of existing facilities,
     guide counsel,  and consulting engineers
     in designing needed  improvements and

This outline was prepared by A.W. West,
Chief,  Operation and Design,  Division
of Field Investigations, Cincinnati
Center, EPA,  Cincinnati, OH  45268.

                                     TRICKLING FILTERS

 A  Trickling filters have been used for many
    years for the treatment of municipal liquid
    biological wastes. Although it is one of the
    oldest treatment devices,  the  relationship
    among the factors affecting the amount of
    waste removal achieved in a trickling filter
    has remained obscure.

 B  Trickling filters are not filters at all,  but
    basically only a pile  of rocks providing
    surface area upon which slime organisms
    cling and grow.  These microbes feed on
    the dissolved food matter contained in the
    sewage or industrial waste effluent applied
    to the filter.  When too thick a slime layer
    accumulates, anaerobic conditions develop
    at the media surface. A natural mechanism
    results for  cleaning the filter  with the
    periodic "sloughing" of the slime layer
    from the surface of the filter media.
    These solids that are sloughed off are
    collected through final clarification of the
    filter effluent.

 A  Distribution - rotary or fixed nozzle

    Provides intermittent application,  wets
    all media surfaces, applies sewage
    effluent uniformly.

 B  Media

    Supports slime, provides slime-sewage -
    air interfaces, permits ventilation or
    air flow.

 C  Underdrainage System

    Collects and conveys effluent,  admits or
    draws off air, supports filter media.
  D Secondary Clarifier

    Settles agglomerated solids and "sloughed"
    slime  growths from final effluent,  final
    clarifier overflow rate varying between
    800-1000 gallons per day per square foot

 A Advantages

    1  Relatively high nitrifying effect upon

    2  Low operating cost

    3  Ability to function under extreme
       weather conditions

    4  High efficiency in BOD removal

    5  High efficiency Ln suspended solids

    6  Rugged resistance to shock loads

    7  More complex biota than for activated

 B Limitations

    1  High head losses

    2  Odor and fly nuisances

    3  Large land area required

    4  High initial  construction cost

    5  Head losses may require pumping

    6  Forced ventilation may be necessary

 Trickling Filters
    7  Trickling filter effluent clarification
       may be less complete due to association
       with anaerobic slime layers.

 A  Low Rate or Standard Trickling Filters

    1  Hydraulic loading

       1-4 million gallon per acre per day
       (mgad) 25-100 gpd/sq ft

    2  Organic loading

       220-600 Ibs.  BOD5/acre-ft/day
       5-15 Ibs.  BODS/1000 cu ft

    3  Recirculation

       usually not

    4  Filter  depth

       6-10 ft (ave.  T)

    Most of the very early filters were of
    this  type.

 B  High Rate Trickling Filters

    1  Hydraulic loading
       4-44 mgad
       200-1000 gpd/sq ft

    2  Organic loading

       660-13, 000 Ibs. BOD5/acre - ft/day
       15-300 Ibs.  BOD5/1000 cu ft

    3  Recirculation

       normally provided

    4  Filter depth

       3-7 ft (ave. 5')

    Most of the filters constructed in recent .
    years have been high-rate filters.  These
    filters were built with various depths, and
    organic loadings.
   The performance of biological treatment
   units of this type is dependent upon the
   volume of ACTIVE growth present in and
   on the filter media.  The size of the filter
   and the filter media determine the amount
   of space available for the growth of the
   biological slime mass.

   The rate  of application of the waste
   influences the amount of growth that will
   develop.  The two types of loading
   (i. e. organic loading and the volumetric
   or hydraulic loading) have opposite effects.
   The greater the amount of available
   organic matter,  the greater the food
   supply and expected growth.  Recirculation
   increases trickling filter efficiency,
   however, high dosage rates  increase
   scour,  dislodge slime growth, and reduce
   the volume of active growth  present in
   and on the filter media. It is noted that
   organic loading has greater  influence  on
   trickling  filter efficiency than hydraulic

C  Super Rate or Roughing Filters

   1  Hydraulic loading

      up to 1000 mgad

   2  Organic loading

      (see comment noted below)

   3  Recirculation

      normally provided

   4  Filter depth

      up to 40 feet using manufactured
      plastic filter media instead of rock
      or stone

   This process is usually associated
   primarily with treatment of  industrial

   In some recent filter designs, loads
   greater than those for the high-rate filters
   have been used. This is particularly  true
   for manufactured filter media.  Presumably
   the ratio  of the useful surface area of the

                                                                          Trickling Filters
   media to the volume of the media is
   greater for cases in which higher
   efficiency of BOD removal per unit volume
   of filter is obtained.

   It appears that some allowance, by use of
   some factor,  for the effect of increased
   surface area within the same volume of
   manufactured filter media should be made.
 A  Common Flow Diagrams

    1  A general flow diagram which represents
      most of the possibilities of recirculation
      of effluents and underflows is shown in
      Figure 1 could be cut off between the
      intermediate clarifier and the second
      stage filter,  discarding the second
      stage filter and final clarifier.

    2  Figure 2 shows a few of the more
      common flow diagrams.

 B  Factors in Trickling Filter Design

    It appears that the efficiency  of a trickling
    filter is dependent upon all or some of the
    following variables:

    1  Composition and  characteristics of the
      waste influent

    2  Organic loading to be applied to the

    3  Pretreatment by  sedimentation or other

    4  Hydraulic loading to be applied to the
      filter-recirculation ratio and system

    5  Filter bed characteristics; volume,
      area, and depth

    6  Type of filter media selected; such as
      surface to volume of support media and
      void space

    7  If aeration  or forced ventilation is to
      be provided
   8  Wastewater and air temperature

C  Effects of Recirculation

   1  Part of the organic matter in the  raw
      waste feed is brought into contact with
      the  slime  organisms more than once.

   2  Recirculated  effluent  contains active
      microorganisms not found in such
      quantity in raw waste, thus providing
      seed continuously.

   3  Diurnal organic waste loadings are
      distributed more  evenly.

   4  The continuation of waste application
      to the filter during periods of low
      flows  (night time) precludes long
      detention periods which may result
      in septicity.  Stale sewage is freshened.
      Slimes do not dry out.

   5  Increased hydraulic loading through
      recirculation improves uniformity
      of waste distribution,  increases
      sloughing,  and  reduces clogging

   6  Higher velocities and continual scouring
      also produces conditions less  favorable
      for the growth of filter flies.

   7  Continual  seeding with active slime
      organisms and  enzymes stimulates
      hydrolysis and  oxidation and increase
      the  rate of biochemical stabilization
      of the waste.

   8  Recirculation will increase operating
      costs  because of the necessary pumping
      of the return  effluent.

   9  Wastewater temperatures may be
      reduced as a  result of the number of
      passes of the  liquid through the filter.
      During cold weather,  this may result
      in decreased  biochemical activity and
      reduced efficiency of treatment

This outline was prepared by J.A.  Montgomery,
Sanitary Engineer,  EPA Manpower and
Training Activities, PNWL,  Corvallis,  OR.

Trickling Filters
                       TRICKLING  FILTER  FLOW AND RECYCLE
                      UNDERFLOW RECYCLE
                           UNDERFLOW RECYCLE
                                      FIGURE 1
                       TRICKLING  FILTER FLOW  AND  RECYCLE
                                                   SECOND STAGE RECYCLE
                               FIRST STAGE RECYCLE
                              SECOND STAGE RECYCLE
                                         FIGURE 2


 A Lagoons receiving raw sewage have
   become very popular, particularly among
   smaller  municipalities where low con-
   struction and operating costs usually offer
   a significant financial advantage over
   other conventional treatment methods.
   Lagoon installations in the Missouri
   Basin serving as the sole mode of treatment
   now number several thousand.

 A As early as 1920, a few cities in
   California,  Texas, North Dakota,  and
   probably other states were using lagoons
   as a means of treating municipal sewage.
   However, in each case it  seemed to be
   more the result of accident than actual

   1  About this time, a student of the
      University of Texas made  a study for  the
      State Department of Health to ascertain
      why sewage from the town of Palestine,
      which was discharged into a small
      swampy area, was converted  to a fresh
      sparkling stream after a few miles.
      The report that aquatic plants played
      an important  part in the oxidation of
      this sewage was subjected to ridicule.
      However, a short time later,  the State
      Sanitary  Engineer recommended that
      Abilene,  Texas construct a small dam
      and pond their sewage until a  sewage
      treatment plant could be built.  This
      early lagoon functioned successfully,
      and during the 1930's Texas A &. M
      College became interested in  the
      operations at Abilene and constructed
      a 14-acre unit to  carry on limited
      investigations of lagoon operation.
      What happened to this study is not known.

   2  In 1924 Santa Rosa, California in an
      attempt to provide low-cost sewage
      disposal, uncovered gravel beds which
      the City Council thought could be used
     as natural filters before the city
     sewage was discharged into Santa Rosa
     Creek.  The exposed gravel soon
     became sealed from sewage solids,
     resulting in a  sewage pond about
     3 feet deep. The effluent  from the
     pond resembled the effluent from a
     trickling filter.  It had no odor and
     was easily  disinfected.  Also, in 1924,
     Vacaville,  California constructed a
     small reservoir in a dry gully to
     impound sewage during the winter
     months only.  Here again,  it was
     found that this impounded  sewage
     underwent characteristic reduction in
     BOD and increased in dissolved oxygen.

   3  In 1928, Fessenden, North Dakota,
     completed a sewer system but did not
     have funds  to complete a treatment
     plant.  As an emergency measure,  the
     sewage was drained into a pothole
     about a mile from town. Forty years
     later, this  natural lagoon  is still in

   4  The success of these early enterprises
     eventually gave engineers and health
     authorities some degree of confidence
     that a raw sewage lagoon could be
     designed and operated  satisfactorily in
     close proximity to a City.

B  Modern Raw Sewage Lagoons

   1  The first lagoon built on sound
     engineering principles  under modern
     concepts of treating raw sewage,  was
     the one placed in operation in 1948 at
     Maddock,  North Dakota.  To my
     knowledge, this was the first lagoon
     built to receive raw sewage under
     plans formally approved by an official
     Health Agency.  "Engineered lagoons"
     had been built in both Texas and
     California before this time, but to
     receive effluent from primary treat-
     ment plants rather than raw sewage.
     For the most part,  the  early facilities
     in Texas and California were apparently
 SE.BI.sta. 19.7.68

Experience in the Use of Raw Sewage Lagoons
     constructed to store partially treated
     sewage effluents for subsequent release
     for irrigation.

   2 Maddock is a town of approximately
     1, 000 people.  The initial design
     provided 10 acres of water service in
     a single cell, a level bottom,  a water
     depth of 5 feet, and uniform bank slopes.
     Observations of this facility and
     laboratory analysis confirmed that a
     high degree of BOD reduction prevailed
     at any point 50 feet or  more from  the
     inlet at the  center of the pond.

   3 The success of this installation created
     considerable enthusiasm by engineers
     of the North Dakota State Health
     Department, and they  soon became
     active promoters of lagoons as an
     accepted method of sewage treatment.
     Several towns in North Dakota constructed
     lagoons in 1949.  It should be mentioned
     that these facilities, and the engineers
     recommending them,  were harshly
     criticized for what was then considered
     a backward step in sewage treatment.
     With very few exceptions,  consulting
     engineers in particular were reluctant
     to accept lagoons as sewage treatment

   4 A  few City Councils recognized lagoons
     as the most economic  solution to their
     money and water pollution problems,
     and insisted that lagoons rather than
     conventional plants be designed and
     constructed. In some instances,
     communities previously unable to
     finance both a sewer system and con-
     ventional  sewage treatment works,
     were  able and did construct sewer
     systems and lagoons.

   5 Endorsement by the U. S. Public Health
     Service of lagoons as an acceptable
     method of sewage treatment was first
     given by the Missouri  Drainage Basin
     Office, serving a 10-state area in
     Midwestern United States. As engineer
     in charge of the Water Pollution Control
     Program  of the Public Health Service
     in the Missouri Basin, my own
     observations,  supported by the
     investigative work by Dr.  Joe K. Neel,
     biologist on my staff, permitted us to
     officially endorse this method of
     sewage treatment.

   6  Enthusiasm also spread to the Taft
     Sanitary Engineering Center of the
     Public Health  Service in Cincinnati,
     Ohio, as W.W. Towne,  then in charge
     of Field Investigations at the Center,
     became actively interested in
     investigations of facilities then existing
     in North and South Dakota. In 1954
     the Public Health Service  started
     limited field investigations of  3  lagoons
     in each of the  3 states.  The report
     brought about  a degree of  respectability
     that raw sewage lagoons had not
     previously enjoyed.  Today, lagoons
     are being used in virtually every State
     in the Union, but nowhere do they
     predominate in sewage works  con-
     struction as they do in the Missouri

C  Missouri Basin Standards

   1  One by one and with varying degrees
     of enthusiasm, the  State Sanitary
     Engineers of the 10 Missouri Basin
     States began to accept raw sewage
     lagoons.   Each state promulgated its
     own design standards and  criteria,
     although each was  generally patterned
     after the original installations in
     North Dakota.  The great  upsurge of
     interest in the use of lagoons at many
     localities  throughout the Basin soon
     emphasized the desirability of
     documenting the design, construction
     and operation practices generally used.
     At its 1958 meeting at Deadwood,
     South Dakota,  the Missouri Basin
     Engineering Health Council, consisting
     of the Chief Sanitary Engineer of each
     of the 10 Basin States,  recognized this
     need and appointed a committee to
     accomplish the objective.  It was  my
     good fortune to be one of the three men
     appointed to the Committee, and my
     further good fortune that I was requested
     to develop a preliminary draft of a
     report for review by the other two
     members of the Committee.

                                                Experience in the Use of Raw Sewage Lagoons
   2 Upon acceptance by the three-man
     committee, the draft was submitted to
     each of the  10-state Sanitary Engineers
     for review and comment.  A succession
     of drafts and redrafts followed, and
     eventually one was acceptable to each
     of the  10 states.  This draft was
     approved by the Missouri Basin
     Engineering Health Council at its
     meeting in Jefferson  City, Missouri
     on January  21, 1960.  The Committee
     report was  carried in the September
     1960 issue of  the Journal Water Pollution
     Control Federation.  Today it still
     constitutes  the most reliable treatise on
     design, construction and operation
     practices of raw sewage.

D  Treatment Process

   Primary and secondary treatment processes
   are  usually accomplished in separate units.
   A lagoon accomplishes both gravity
   separation and biological reduction in a
   single unit.

   1 Sludge settles to the bottom.  Except
     in the vicinity of the inlet, it is rather
     uniformly distributed over the  entire
     lagoon bottom.  Circulation resulting
     from surface winds and convection
     currents contribute to the scatter.

   2 Sludge decomposition progresses
     somewhat comparable to an unheated
     digester.  The liquid immediately
     above the sludge layer is anaerobic, but
     the upper portion of the water reservoir
     is normally aerobic.  As hydrogen
     sulphide is  released,  it passes upward
     through the aerobic zone and reacts with
     water before reaching the open
     atmosphere.  Objectionable odors may
     develop only when the entire water
     strata is anaerobic.   Freedom from
     odor is assured only when oxygen is
     present in the upper layers.  Oxygen
     production must thus  exceed the  demands
     of organic decomposition.

   3 Light intensity seems to be the most
     important influence upon the rate of
     photosynthesis.  The  rate declines with
     the autumn and winter declines in light
   intensity, with a corresponding
   resurgence in the spring and following
   periods of overcast.

   a  Observations by the Public Health
     Service at Fayette, Missouri have
     shown that there should be at least
     1  1/2 langleys of solar radiation
     (1  langley =  1 gram calorie per CM  )
     per day for each pound of BOD
     applied per acre of lagoon surface/
     day. To insure a safety factor 1 Ib
     of  BOD per acre for  2 langleys is
     suggested.   Loading  in Ibs BOD per
     acre per day should thus be  equal to
     one half the  minimum daily langley
     level for the month with least  solar
     radiation. This relation does not
     hold if ice cover endures over the
     winter  months.

4  The lagoon provides an environment
   favorable for the interactions of algae
   and bacteria.   Bacteria  feed upon
   constituents of sewage in solid form
   and in solution and render them
   innocuous.  Algae utilize carbon dioxide
   and other substances resulting from
   bacterial action and,  through photo-
   synthesis, produce oxygen needed for
   anaerobic bacterial action. During the
   detention period, the objectionable
   characteristics of sewage  largely

5  Lagoons normally employ  a detention
   period of 60 to 90 days,  although
   detention  over  120 days  is not uncommon.
   A  detention as  short as 30 days insures
   a high degree of coliform removal.

   a  Series  installations increase BOD
     removals.  Effluent from secondary
     units of a series operation has
     lower concentrations  of algae,  color,

   b  Design of installations in series must
     recognize that the  entire sludge
     load will adhere to the primary cell.

Experience in the Use of Raw Sewage Lagoons
E  Advantages of Lagoons

   1 Construction cost is usually much lower
     than for other treatment processes.
     For smaller communities, where
     suitable land is often readily available
     at reasonable cost, the cost of sewage
     treatment may be reduced by more
     than 50 per cent.

     a  Many smaller  communities previously
        unable to finance a sewage system and
        treatment works have been able to
        finance their sewer system and a
        lagoon for treatment.

     b  In certain states,  lagoons  have saved
        communities more than they have
        gained through Federal Aid.

   2 The cost of maintenance is much lower.
     Highly skilled operators are  not required.
     Maintenance is usually limited to weed
     control and dike maintenance.  Break-
     downs are  virtually non-existent.

   3 A  lagoon has tremendous ability to
     handle shock loads.  The "slug" is
     immediately diluted,  and tremendous
     "slug loads" are  required to  upset the
     lagoon process.

     a  Lagoons are well suited for  summer
        camps,  rural schools, motels,
        resorts,  slaughter houses, livestock
        operations, etc.  Missouri is
        estimated to have more than 1, 000
        non-municipal lagoons.

     b  Design may provide for complete
        retention, or may provide for con-
        trolled release at a non-critical time.

   4 Lagoons may serve well as interim
     facilities in developing areas.  When
     development is adequate to support
     trunk or interceptor sewers, the
     lagoon can be abandoned at little loss
     of investment. Increase in land values
     may even offset all construction costs.
     This has been widely practiced in
     Kansas City, where approximately
     40 developer financed lagoons have
     served as interim facilities.
  a  Under its revenue bond program,
     Kansas City has constructed 2
     lagoon systems to serve the
     intermediate portions of large
     watersheds, pending the develop-
     ment of sufficient customer load to
     warrant construction of 8 to 12
     miles of large diameter sewers.

5 Lagoons may be used for treating
  industrial wastes that are amenable
  to biological treatment,  or a mixture
  of organic industrial wastes and
  domestic sewage.  Installations are now
  successfully serving oil refineries,
  slaughter houses, dairy and creamery
  establishments, poultry processing
  plants,  and rendering plants.  Special
  study should be given industrial wastes
  whenever they constitute a significant
  portion of the total load.  Possible
  toxic effects of industrial wastes
  should not be overlooked.  Toxic
  materials in concentration that would
  interfere with other biological sewage
  treatment processes should be handled
  in lagoons only after thorough study
  and evaluation.

6 Lagoons may  receive raw sewage, or
  the effluent of a conventional  treatment

  a  Numerous instances can be cited
     where lagoons provide "polish
     treatment, " following a trickling
     filter or activated sludge plant.
     They are particularly effective in
     coliform reduction.

  b  Where provided initially to receive
     raw  sewage from sparsley developed
     areas,  lagoon designed to receive
     raw  sewage may later be used  to
     provide secondary treatment,  as
     primary treatment facilities are
     provided to  relieve the overload
     from increased  development.

      1) This has been used very
        successfully at Kansas  City in
        the intermediate reaches of the
        Little Blue River Basin, and
        comparable use is planned in  our
        Shoal Creek  Watershed.

                                               Experience in the Use of Raw Sewage Lagoons
   7 Lagoons surpass other conventional
     treatment processes in reduction of
     total phosphorus and total nitrogen.

     a  Investigations at Fayette, Missouri
        demonstrate consistent reductions
        of total phosphorus by 85 per cent;
        and total nitrogen by 92 per cent.

F  Disadvantages of Lagoons

   1 Too little is known regarding the many
     factors  which affect optimum performance
     of lagoons.  Unfortunately, lagoons
     have remained beneath the dignity of
     established research talent.  As a
     result,  research in this field has been

   2 Too frequently,  lagoons are permitted
     to operate with no supervision or
     control.  Overloading is not prevented,
     and the  problem is not apparent until
     some critical circumstance occurs --
     as a long period of cloudy weather or
     an abrupt change from cold to warm
     weather.  Little can be done to prevent
     reoccurrence of the problem.

   3 With a breakdown in the process,
     lagoons  become  quite odorous.  With
     the large area of water surface, a
     severe nuisance can occur over a wide

   4 A lagoon requires a much greater land
     area than do other treatment processes.
     Add to this basic area the distance that
     should be provided to reasonably isolate
     a sewage plant,  and a very large area
     results.  This may be feasible for an
     interim  period but not as a permanent
G  Summary

   1  Sewage lagoons are a proven and
     demonstrated method of satisfactory
     waste disposal to be considered along
     with other accepted methods  of treat-
     ment, in the  engineering and economic
     analysis  that leads to the final selection
     of a  sewage treatment process.  This
     does not  imply that the lagoon is the
     answer to all sewage problems.
     However, a lagoon provides the most
     feasible method of sewage treatment
     in many instances.

   2  Reference material

     a  The most imformative document on
        the design, construction and opera-
        tion of lagoons is  the Committee
        Report of the Missouri Basin
        Engineering Health Council.   I have
        with me  several copies of  this
        publication for any one interested.

     b  Proceedings of Symposium on
        Waste Stabilization Lagoons.  This
        Symposium was conducted at Kansas
        City,  Missouri, August 1-5,  1960
        by Region  VI,  Public Health Service,
        at the  request of the 10 states of the
        Missouri Basin.   I believe the
        Kansas City office of FWPCA still
        has a limited supply of this publica-
        tion, and that  it can be made
        available upon request.
     Poor maintenance may lead to emergent
     vegetation, which in turn can lead to
     mosquito propagation.  The major
     species produced in lagoons are culex
     tarsalis and culex pipiens --  both
     primary vectors of  encephalitis.
     Mosquitoes do not propagate in a
     properly maintained lagoon.
This outline was prepared by G. J.  Hopkins,
Director, Water and Pollution Control
Depts., City of Kansas City, MO  64106.

                         SAMPLING IN WATER QUALITY STUDIES

 A  Objective of Sampling

    1  Water quality characteristics are not uni-
      form from one body of water to a another,
      from place to place in  a given body of
      water, or even from time to time at a
      fixed location in  a given body of water.
      A sampling program should recognize
      such variations and provide a basis for
      interpretation of their  effects.

    2  The purpose of collection of samples is
      the accumulation of data  which can be
      used to interpret the quality or condition
      of the water under  investigation.  Ideally,
      the sampling program  should be so de-
      signed that a statistical confidence limit
      may be associated  with each element of

    3  Water quality surveys  are undertaken
      for a great variety of reasons.  The
      overall objectives of each survey greatly
      influence the location of sampling
      stations,  sample type,  scheduling of
      sample collections, and other factors.
      This influence should always be kept  in
      mind during  planning of the survey.

    4  The sampling and testing program should
      be established in accordance with princi-
      ples which will permit  valid interpretation.
         The collection,  handling, and testing
         of each sample should be scheduled
         and conducted in such a manner as
         to assure that the results will be
         truly representative of the sources of
         the individual samples at the time and
         place of collection;

         The locations of sampling stations
         and the schedule of sample collections
         for the total sampling program should
        be established in such a manner that
        the stated investigational objectives
        will be met; and

     c  Sampling should be sufficiently
        repetitive over a period of time to
        provide valid data about the condition
        or quality of the water.

B  Sample Variations

   Interpretation of survey data is based on
   recognition that variations will occur in
   results from individual samples.  While
   it is beyond  the scope of this discussion
   to consider the implications of each in
   detail,  the following can be identified as
   factors producing variations in data and
   should be considered in planning the sam-
   pling program.

   1 Apparent variations

     a  Variations of  a statistical nature,
        due to collection of samples from
        the whole body of water,  as  con-
        trasted with examination of ail  the
        water  in the system.

     b  Variations due to inherent precision
        of the  analytical procedures.

     c  Apparent variations are usually
        amenable to statistical analysis.

   2 True differences

     a  Variations of a cyclic nature

        Diurnal variations, related to alter-
        nating  periods of sunlight and

        Diurnal variations related to waste
        discharges from  communities.
WP. SUR. sg. la. 6. 66

Sampling in Water Quality Studies
         Seasonal variations, related to
         temperature and its subsequent
         effects on chemical and biological
         processes and interrelationships.

         Variations due to tidal influences.
         in coastal and estuarine waters.

      b  Intermittent variations

         Dilution by rainfall and runoff.

         Effects of irregular or intermittent
         discharges of wastewater, such as
         "slugs" of industrial wastes.

         Irregular release of water from
         impoundments, as from power

      c  Continuing changes in water quality

         Effects downstream from points of
         continuous release of wastewater.

         Effects of confluence with other
         bodies of water.

         Effects of passage of the water
         through or over geological forma-
         tions of such chemical  or physical
         nature as to alter the characteristics
         of the water.

         Continuing interactions of biological,
         physical, and chemical factors in
         the water, such as in the process of
         natural self-purification following
         introduction of organic contaminants
         in a body of water.

 A  The Influence of Survey Objectives

    Much of the sampling design will be
    governed by the stated purpose of the
    water investigation.  As an example  of
    how different objectives might influence
    sampling design, consider a watercourse
    with points A and B located as indicated
    in Figure 1.
             Figure 1

Point A can be the point of discharge of
wastes from Community A.  Point B can
be any of several things,  such as an intake
of water treatment plant supplying Com-
munity B, or it might  be the place where
the river crosses  a political boundary, or
it may be the place where  the water is
subject to some legitimate use,  such as
for fisheries or for recreational use.

1  Assume  that the objective of a water
   quality investigation is  to determine
   whether  designated standards of water
   quality are  met at a water plant intake
   at Point  B.  In this case, the objective
   only is concerned with the quality of the
   water as it  is available at Point B.
   Sampling will be conducted only at
   Point B.

2  Alternately, consider that there is a
   recognized  unsatisfactory water quality
   at Point  B,  and it is alleged that this
   is due to discharges of inadequately
   treated wastes, originating at Point A.
   Assume  that the charge is to investigate
   this allegation.

   In this case the selected sampling sites
   will include at  least three elements:

   a  At least one  sampling site will be
      located upstream from Point A,  to
      establish base levels of water quality,
      and to check the possibility that the
      observed conditions actually originated
      at some point upstream  from Point A.

   b  A site or sites must be located down-
      stream from Point A.  Such a site
      should be downstream a sufficient
      distance to permit adequate mixing in
      the receiving water.

   c  Sampling would be necessary at Point
      B in  order to demonstrate that  the
      water quality is in fact impaired, and
      that the  impairment is due to influences
      traced from Point A.

                                                           Sampling in Water Quality Studies
B  Hydraulic Factors

   1  Flow rate and direction

      a  In a survey of an extended body of
         water it is necessary to determine
         the rate and direction of water move-
         ment influences selection of sam-
         pling sites.  Many workers plan
         sampling stations representing not
         less than the distance water flows
         in a 24-hour period.   Thus,  in
         Figure 1,  intervening sampling
         stations would be  selected at points
         representing the distance water
         would flow in about 24 hours.

      b  In a lake or impoundment direction
         of flow is the major problem influenc-
         ing selection of sampling stations.
         Frequently it is necessary to estab-
         lish some sort  of grid network of
         stations in  the vicinity of the sus-
         pected sources  of pollution.

      c  In a tidal estuary,  the oscillating
         nature of water movement will re-
         quire establishment of sampling
         stations in both directions from
         suspected sources of  pollution.

   2   Introduction of other water

      a   In situations in which  a stream being
         studied is joined by another stream
         of significant size and character,
         sampling stations will be located
         immediately above the extraneous
         stream, in the extraneous stream
         above its point of juncture with the
         main stream, and in the main
         stream below the point of juncture.

      b   Similar stations will be needed with
         respect to other water discharges,
         such as from industrial outfalls,
         other communities, or other  instal-
         lations in which  water is introduced
         into the main stream.

   3   Mixing

      a  Wherever possible, one sampling
        point  at a sample collection site is
         used in stream surveys.  This
         usually is near the surface of the
         water,  in the main channel of flow.

      b  In some streams mixing does not
         occur quickly, and introduced water
         moves downstream for considerable
         distances below the  point of con-
         fluence with the main streams.
         Example:  Susquehanna  River at
         Harrisburg, where 3 such streams
         are  recognizable in the  main river.
         Preliminary survey operations
         should identify such situations.

         When necessary, collect separate
         samples at two or more points
         across  the body of water.

      c  Similarly, vertical mixing may not
         be rapid.  This is noted particularly
         in tidal estuaries, where it may be
         necessary to make collections both
         from near the bottom and near the
         surface of the water.

      d  Collection of multiple samples from
         a station  requires close coordination
         with the laboratory, in terms of the
         number of samples that can be
         examined.  Some types  of samples
         may be  composited.   The  decision
         must be reached separately for each
         type of sample.

C  Types of Analytical Procedure

   1  Samples collected for physical,  chemi-
      cal, and bacteriological tests and
      measurements may be  collected from
      the same series of sampling  stations.

   2  Sampling stations selected for biological
      (ecological)  investigation require
      selection of a series of similar  aquatic
      habitats (a series of riffle  areas, or a
      series  of pool areas, or both).  The
      sites used by the aquatic biologist may
      or may not be compatible with those
      used for the rest of the survey.   Accord-
      ingly,  in a given stream survey, the
      stations used by the aquatic biologist
      usually are somewhat different from the
      stations used for other examinations.

 Sampling in Water Quality Studies
 D Access to Sampling Stations

    For practical reasons,  the sampling site
    should be easily reached by automobile if
    a stream survey, or by boat if the survey
    is on a large body of water.  Highway
    bridges are particularly useful, if the
    sample collector can operate in safety.

 A Survey Objectives

 B Time of Year

    1  In short-term water quality investiga-
       tions, particularly in pollution
       investigations, there often is need to
       demonstrate the extremes of pollution
       effects on the  aquatic environment.
       For this reason,  many short-term
       surveys are conducted during the
       warmer season of the year,  at such
       times as the water flow rate and
       volume  is at a minimum and there is
       minimum likelihood of extensive

    2  In a long-term investigation, sampling
       typically is conducted at all seasons
       of the year.

 C  Daily Schedules

    As shown in an introductory paragraph,
    water quality is subject to numerous
    cyclic or intermittent variations.  Sched-
    uling of sample collections should be de-
    signed to reveal such variations.

    1  In short-term surveys it is common
       practice to collect samples from each
       sampling site  at stated intervals through
       the 24-hour day,  continuing the program
       for 1-3 weeks.  Sampling at 3-hour
       intervals is preferred by many workers,
       though practical considerations may re-
       quire  extension to 4- or even 6-hour
    2 In an extended survey there  is a ten-
      dency to collect samples from each
      site at not more than daily intervals,
      or  even longer.  In such cases the
      hour of the day should be varied through
      the entire  program., in order that the
      final survey  show cyclic or intermittent
      variations if they  exist.

    3 In addition, sampling  in tidal waters
      requires consideration of tidal flows.
      If samples are collected but once daily,
      many workers prefer  to make the col-
      lections at low slack tide.

    4 In long-term or any other survey in
      which only once-daily samples are
      collected,  it is desirable to  have an
      occasional period of around-the-clock


 A River Mile System

    The FWPCA method of identifying  points
    on a water course is by  counting river
    miles from the mouth (or junction  with a
    larger stream) back to the source.  This
    should not be confused with other systems,
    such  as those in  which the river mile is
    started at the source of  the stream and
    proceeds to the mouth of the stream or
    confluence with another  body of water.

 B STORET System

    The STORET System is  a computer-oriented
    data processing system  used by FWPCA for
    storage, retrieval,  and  analysis of water
    quality data collected by federal, state,
    local, and private agencies.

    The system includes a complex system  -
    based on the  river mile  system - for
    identifying sampling locations  on all rivers
    ind streams in the United States.   A recent
    addition to the system introduces a location
    procedure based on geographic coordinates;
    this procedure  is especially adapted to
    location of sampling stations in large bodies
    of water such as  lakes and impoundments.

                                                           Sampling in Water Quality Studies
    Not all locations have been coded at this
    time,  although the coding systems have
    been established.  The interested worker
    should consult Public Health Service Publi-
    cation No.  1263,  "The Storage and  Retrieval
    of Data for Water Quality Control. " 1963.


 A  Types of Samples

    1   "Grab" sample - a grab sample is usually
       a manually collected single portion  of the
       wastewater or stream water.  An analysis
       of a grab sample shows the concentration
       of the constituents  in the water at the time
       the sample was taken.

    2   "Continuous"  sample - when several points
      are to be sampled at frequent intervals or
      when a continuous record of quality at a
      given sampling station is required,  an
      automatic or continuous sampler  may be

      a  Some automatic samplers collect a
         given volume of sample at definite time
         intervals; this is satisfactory when the
         volume of flow is constant.

      b  Other  automatic samplers take samples
         at variable rates in proportion to chang-
         ing rates of flow.  This type of sampler
         requires some type of flow measuring

    3  "Composite"  sample - a composite
       sample is the collection and mixing
       together  of various individual samples
       based upon the ratio of the  volume of
       flow at the time the individual samples
       were taken to the total cumulative
       volume of flow.  The desired composite
       period will dictate the  magnitude of the
       cumulative volume of flow.  The  more
       frequently the samples are collected,
       the more representative will be  the
       composite sample  to the actual situa-
       tion.  Composite samples may be
       obtained  by:

       a  Manual sampling and volume  of flow
          determination made when each sam-
          ple is taken.
      b  Constant automatic sampling (equal
         volumes of sample taken each time)
         with flow determinations made as
         each sample is taken.

      c  Automatic sampling which takes
         samples at pre-determined time
         intervals and the volume of sample
         taken is proportional to the volume
         of flow at any given time,

B  Type of Sampling Equipment

   1  Manual sampling

      a  Equipment is specially designed
         for collection of samples from the
         bottom muds, at various depths,
         or at water surfaces.   Special
         designs are related to protection  of
         sample integrity in terms of the
         water characteristic or component
         being measured.

      b  For details of typical sampling equip-
         ment used in water quality surveys,
         see outlines dealing with biological,
         bacteriological, and chemical tests
         in this manual.

      c   Manual sampling equipment has
        very broad application in field work,
        as great mobility of operation  is
        possible,  at lower cost than may be
        possible with automatic sampling

    2  Automatic sampling equipment

      Automatic sampling equipment has
      several important advantages over
      manual methods.  Probably the most
      important consideration is the reduction
      in personnel requirements resulting
      from the use of this equipment.  It
      also allows more frequent sampling
      than is practical manually, and elimi-
      nates many of the human  errors  in-
      herent in manual sampling.

      Automatic sampling equipment has
      some disadvantages.   Probably the
      most important  of these  is the  tendency
      of many automatic devices to become

Sampling in Water Quality Studies
      clogged when liquids high in solids are
      being sampled.  Individual portions of
      composite samples are usually quite
      small which may in  some cases be
      disadvantageous.  In using automatic
      samplers, sampling points are fixed,
      which results in a certain loss of
      mobility as compared to manual

      Automatic sampling equipment should
      not be used indiscriminately;  some types
      of samples - notably bacteriological,
      biological, and DO samples - should
      not be composited.  In cases of doubt,
      the appropriate analyst should be
a  Compositing samplers

   1)  Jar and tube sampler - this type
      samples effectively when flow
      is nearly constant.  As water
      drains from the upper carboy,
      the vacuum created syphons
      waste into the lower one.  The
      rate-of-flow is regulated by the
      pinch clamp to fill the lower
      carboy during the sampling
      period.  (See Figure 2)
                                     *- WASTE SAMPLE   SCREW CLAMF

                                   -WASTE STREAM

                                     C  MUST BE GREATER THAN A+B
                                          Figure 2

                                                  Sampling in Water Quality Studies
2)  Scoop type

   a)  Rotating scoop

      This device consists of a
      power driven scoop mounted
      upstream from a weir.  The
      scoop is so designed and
      mounted that the sample vol-
      ume grabbed on each rotation
      of the scoop is proportional to
      the flow,  as governed by the
      head on the weir.   The scoop
      may be rotated at a constant
      speed or  timed to sample
      at fixed time intervals.

   b)  Revolving wheel with cups
      (Figure 3)

      This device consists of a
      power driven wheel or disc
      mounted upstream from a
      weir.  A number of freely
      suspended buckets are mount-
      ed at varying distances from
      the axis so  that increased
      flow will cause more buckets
      to be filled, thereby giving a
      sample proportionate  to flow.
      Both this  device and the
      rotating scoop sampler can,
      of course, be used for non-
      proportionate sampling.

  c) Bucket elevators

    This device may consist of a
    single bucket alternately
    lowered into and raised out of
    the waste stream,  or it may
    consist of a series of buckets
    on an endless chain passing
    through the waste stream.  In
    either case,  it will  include a
    tripping mechanism to  cause
    the bucket or buckets to spill
    into a sampling funnel.  Both
    types may  be operated  contin-
    uously or timed for intermittent
    operation.  This  method is not
    well adapted to proportionate
                       WEIR CREST
        Figure 3

3  Pumps

   a)  Chemical feed pumps have
      been found useful for sampling,
      because of their ability to
      meter out small doses of
      liquids.  A timing mechanism
      may be used to make the pump
      run for longer periods during
      heavy flow,  thereby allowing
      collection of the sample in
      proportion to flow.  These
      pumps are usually provided
      with adjustable stroke and
      variable speed features which
      allow variation of the volume
      of sample being pumped.
      Figure 4 illustrates a battery
      operated pump.

   b)  Automatic shift sampler
      (Figure 5 )

      Figure 5 shows the automatic
      shift sampler.  It consists
      first of a Randolph or other
      "squeegee-" type pump unit.


Sampling in Water Quality Studies
               The 2-rpm gear motor drives
               the pump at between 1 and 2
               rpm through the spring-loaded
               adjustable-pitch pulley and
               adjustable motor-base arrange-

               We use I/8-in.  (. 32-cm) ID
               or 1/4-in. (, 64-cm) ID
               polyethylene tubing  for sam-
               ple intake from the  waste
               stream.  The sample flow is
               delivered to the distributor
               viaa3/16-in.  (. 48-cm) ID
               Tygon tube  which is supported
               loosely by a wire attached to
               the framework.

               Operation of the distributor is
               very simple.  The 1-rpm clock
               motor powers the chain-and-
               sprocket  drive which turns a
               threaded  bolt.   Rotation of the
               bolt moves  the discharge tube
               down the  plastic trough at a
               rate equal to one division
               every eight hours.  With the
               10 sample-jar receivers the
               timer can be set on Friday,
               and the 9 week-end  shift
               samples can be picked up on
4)  Solenoid-valve arrangements

   A solenoid valve employed in
   connection with a timing device
   may be used for withdrawing
   waste from a pipe under pressure.
   Used in connection with a  pump
   such devices  may be employed in
   sampling free flowing streams.
   (See Figures  6 and 7.)

                                                                              Rerun LM
                   Figure 4
                                                                 Figure 6
                                                      PUMP - SOLENOID VALVE - TIMER
                                                               TYPE SAMPLER
5) Vacuum operated

   In its simplest form,  the vacuum
   is created by a suitably mounted
   siphon.  It collects the sample
   at a uniform rate and is not
   suitable for use when proportional
   sampling  is required.

                                                                Sampling in Water Quality Studies
               Potman of Semo'c
               Twbt One hording ro
               Cotltctlnq v«u*l
               Sample Colliding Vtitil
Rubber Tubing Joint

"Normal Petition of
 Sampling Tub* Returning
 10 S««r
7)  Drip sampler

   Two types of this device are
   illustrated in Figures 9 and 10.
   Both devices are simple methods
   of obtaining  a composite sample
   at a fairly constant rate.
                                                  WIRE ROD SOLDERED
                                                  TO FUNNEL AND BENT
                                                  TO PASS THROUGH
                                                  WATER  JET

                                                         TUNNEL WITH
                                                         NARROW SLOT
                                                         CUT IN SIDE
                   Figure 7
               TYPE SAMPLER
         6) Air vent control

            This  type  of device is illustrated
            in Figure  8.  The rate of sample
         c  collection is  controlled by the
            bubbling mechanism.   It is not
            suitable for use when proportion-
            ate sampling is required.
                            VU.Vt rUKOU-
                  FROM UMPlZft
                  TO BUB81ZR -
                                                                        Figure 9
                                                            FUNNEL AND ROD DIVERTER
                                                       CLUI TUM	,    smlL HO.f.1
                                                            	j    S"*LL HCH
                                                            7   ;~
                                                                                 •vim TU>M notTig um
                                                               sv^      ^K     MK
                  Figure 8
                                     Figure 10
                              DRIP TUBE SAMPLERS

  Sampling in Water Quality Studies
       b  Continuous recording equipment

          Instruments have been developed
          which provide direct measurement
          of temperature, pH, conductivity,
          color,  and dissolved oxygen.  Such
          instruments may be equipped for
          continuous recording.   Instruments
          of this type are quite expensive and
          their installation is often difficult.
          They are best adapted to permanent
          installations,  although good portable
          non-recording instruments are
          available for the measurement of
          temperature,  pH,  and conductivity.
 All procedures in care and handling of sam-
 ples between collection and the performance
 of observations and tests are directed toward
 maintaining the reliability of the  sample as
 an indication of the characteristics of the
 sample source.

 A Sample Quantity

    1  Samples for  a series of chemical
       analyses requires determination of the
       total sample volume required for all
       the tests, and should include enough
       sample in addition to provide a safety
       factor for laboratory errors or acci-
       dents.  Many workers collect  about
       twice the amount of sample actually
       required for the chemical tests.  As
       a rule of thumb, this is on the order
       of 2 liters.

    2  Bacteriological samples, in general,
       are collected in 250 -  300 ml sterile
       bottles; approximately  150  - 200 ml of
       samples is adequate in practically all

 B Sample Identification

    1  Sample identification must  be main-
       tained throughout any survey.  It is
       vital, therefore, that adequate records
       be made of all information  relative to
      the source of the sample and conditions
      under which the collection was made.
      All information must be clearly under-
      standable and legible.

   2  Every sample should be identified by
      means of a tag or bottle marking,
      firmly affixed to the sample bottle.
      Any written material should be with
      indelible marking material.

   3  Minimum information on the  sample
      label should include identification of
      the sample site,  date and time of col-
      lection,  and identification of the
      individual collecting the sample.

   4  Supplemental identification of samples
      is strongly recommended,  through
      maintenance of a sample collection
      logbook.   If not included on the sample
      tag (some prefer to duplicate such infor-
      mation)  the logbook can show not only
      the sample site and date and  hour of
      collection, but also the results of any
      tests made on site  (such as temperature,
      pH,  dissolved oxygen).  In addition, the
      logbook  should provide  for notation of
      any unusual observations made at the
      sampling site,  such as  rainfall, direc-
      tion and strength of unusual winds, or
      evidence of disturbance of the collection
      site by human or other  animal activity.

C  Care and Handling of Samples

   1  As a general policy, all observations
      and tests should be made as soon as
      possible  after sample collection,

      a Some  measurements require perform-
        ance  at the  sampling site,  such as
        temperature,  light intensity (if
        determined), flow-rate, etc.

      b Some  tests are best  made at the
        sampling site because the procedures
        are simple,  rapid,  and  of acceptable
        accuracy.  This  may include such
        determinations as pH and  conductivity.

      c Some  additional  determinations, such
        as alkalinity,  hardness, dissolved

                                                        Sampling in Water Quality Studies
      oxygen, and turbidity may be made
      in the field, provided that ease, con-
      venience,  and reliability of results
      are acceptable for the purposes of
      the  study.
2  Samples to be analyzed in the laboratory
   require special protection to assure that
   the quality measured in the sample repre-
   sents the condition of the source.  Many
   samples,  especially those subjected to
   biological analysis, require special pre-
   servation, protection,  and handling pro-
   cedures.  Incase of doubt, the appropriate
   analyst should be consulted. Most com-
   mon procedures for sample protection
   a  Examination within brief time after

   b  Temperature control.

   c  Protection  from light.

   d  Addition of preservative chemicals.

   Applications of these sample protective
   procedures are along the  following

3  Early examination of sample

   Applicable to all  types of samples.

4  Temperature control

   a  All biological  materials for examina-
      tion in a living state should  be iced
      between collection and examination.

   b  Bacteriological samples, according
      to "Standard Methods" should be
      maintained at  the same temperature
      as the source  of the  sample between
      collection and starting the laboratory
      tests.  Most survey workers, how-
      ever,  continue to ice samples and
      start laboratory tests within 6 hours
      after collection.

   c  Chemical samples often require

      Samples for dissolved  oxygen can
      be maintained several  hours if kept
      iced, and protected from the light.
      BOD samples can be held several
      hours in an iced condition.

      Quick freezing will permit retention
      of many samples for up to several
      months prior to  laboratory examina-

5.  Protection from light

   a  Any constituent of water which may
      be influenced by physiochemical
      reactions involving light should be
      protected.  DO samples brought to
      the iodine stage, for example, should
      be protected from  light prior  to

   b  In addition, any  water constituent
      (such as dissolved oxygen) which
      may  be influenced  by algal activity
      should be protected from light.

6  Addition of chemical preservatives

   a  Bacteriological samples never
      should be "protected" by addition
      of preservative agents.  The only
      permissible chemical additive is
      sodium thiosulfate, which is used
      to neutralize  free residual chlorine,
      if present.

   b  Samples for biological examination
      should be protected by chemical
      additives only under specific
      direction of the principal biologist
      in a water quality study.  Limited
      applications of chemical preserva-
      tives are discussed in the biology
      outlines in this manual.

   c  For chemical tests, preservatives
      are  useful for a  number of water
      components.  The  following examples
      are  cited:

      Nitrogen and  phosphorus analyses:
      The addition of 1 ml concentrated
      H2SO4/liter of sample will retard
      biological activity,  which otherwise
      might alter the  concentration  of
      these constituents.  However,  it
      should be noted that some procedures
      for these determinations will  require


Sampling in Water Quality Studies
        subsequent neutralization of the

        Metals: The addition of 1 -  5 ml of
        acid (HC1,  HNO3, or H2SO4) pre-
        vents precipitation of the metal in
        the container.  The  choice of acid
        depends on what other analyses are
        to be made on the sample (e.g. HC1
        would not be used to preserve a sam-
        ple which later will  be analyzed for

        COD and ABS: Addition of 1 ml
        sulfuric acid per liter of sample  is

        In general,  samples requiring re-
        tardation of biological activity can
        be temporarily preserved by addi-
        tion of chloroform; tests should be
        run as soon as possible,  however.

        Determination of ratio of volatile
        to suspended solids  can  be delayed
        up to 6 months  if 2% formaldehyde  is
      Cyanide  determinations may be
      delayed temporarily through addition
      of alkali to the sample.  A few
      pellets of sodium hydroxide are

      Sulfide analysis may be delayed up
      to as much as 6 months by addition
      of 2 ml/liter of sample of 2N solu-
      tion of zinc acetate.

      Phenol analysis can be delayed
      temporarily by acidification to below
      pH 4. 0 with phosphoric acid and
      preservation with 1 gram CuSC>4
      per  liter of sample.

1  Standard Methods for the Examination of
      Water. Sewage and Industrial Wastes.
      12th Ed. A. P. H. A.  1965.

2  Planning and  Making Industrial Waste
      Surveys.  Ohio River Valley Water
      Sanitation  Commission.

3  Industry's Idea Clinic.  Journal of the
      Water Pollution Control Federation.
      April,  1965.

 This outline was prepared by H. L. Jeter,
 Director, National Training Center, WQO,
 EPA, Cincinnati, OH  45226 and P. F.
 Atkins,  Jr.,  formerly Sanitary Engineer,
 FWPCA Training Activities, SEC.

I  Another outline considered sampling for
water quality in surface waters.  The labora-
tory analyst will be involved in sampling and
analysis in surface waters and in the treat-
ment plant.  The same principles apply but
the routines are likely to be different because
it is impossible to select a  routine applicable
for biological,  chemical and physical tests
for every flow,  condition, or facility. Each
situation must be considered in terms of test
objectives, site selection, available man-
power,  sample and test variables.

A  The sampling and analysis program are
   expected to provide an estimate of one
   or more important variables that can be
   used as a guide in operations control.

   1  The sample is expected to be repre-
      sentative of materials included at a
      particular location, at a particular
      time (or interval),  at  a particular
      stage of some process.

   2  The analysis can not correct for
      sampling inconsistencies.

   3  Sampling variability depends in part
      upon mixing dynamics at or prior to
      the sampling site and upon the charac-
      teristics of the material.

   4  Variability in sampling can be estimated
      by separate sample analysis (catch or
      grab samples) taken at various points
      on a dimensional reference of cross
      section (surface and depth) or at one
      or more points at various intervals
      of time.

   5  A true average ideally would include
      analysis of the entire sampling mass
      according methodologies giving pre-
      cise and accurate results.  This rarely
      can be achieved or  would be desired,
      hence,  we sample to arrive at a practi-
      cal compromise of  effort and information.
          The average can be approximated
          in terms of cross section and time
          from results on a composite  of
          separate samples.

          A more valid estimate of the average
          results  are possible when the indi-
          vidual samples are proportioned  to
          flow or  mass in the composite.
 II  Treatment operations require sampling
 and analysis for two primary objectives:

 A Record results are essential to show what
    entered the plant and what left  the plant
    in terms of concentration, condition, and

 B Control of operations involves  optimization
    of conditions favoring better ratios of
    benefit per unit of time, space, cost or
Ill  The sampling program should be a cooper-
 ative effort among supervisors, operators,
 samplers, analysts and other interested
 parties.   It should be checked for validity
 and applicability of information obtained and
 reviewed periodically or  whenever conditions
 may have changed.

 A Each  installation is limited in manpower
    skills and equipment,  some more than
    others.  A compromise must be reached
    that will provide essential information for
    that particular situation.

 B Each  part of the team  should be clearly
    aware of what samples to obtain, why,
    where,  when and how they are to be used.
    The operation must be  scheduled for
    smooth working arrangements.

    1  The  sampler must be aware that he is
       responsible for the starting point in
       a series consisting of sampling.
PC.3. 10.67

 Sampling in Treatment Plant Operations
       determination, reporting,  and use of
       the derived information.

       a  Sampling must follow prescribed
          location, time and technique schedules
          agreed upon beforehand and tested
          for validity in line with operation

       b  Each sample must be clearly identi-
          fied  according to the designated
          system  in terms of location, time,
          type, etc.  Unusual conditions  that
          may affect results should be noted
          on the identification tag.  Marked
          changes  in sample characteristics
          should be reported promptly to
          proper authority for possible cor-
          rective  action.

       c  Samples should be stored under
          conditions minimizing changes
          before analysis.
IV  Treatment plant samples involve a high
  degree of variability and changes in charac-
  teristics within the plant.

  A The influent  samples are subject to greater
    variability than samples from any other
    part of the plant or the receiving water.

    1  The influent flow contains  a variety of
       materials under unstable conditions.

       a  Certain components are readily
          separated from  the flow because of
          size,  density, volatility or other

       b  Highly putrescible material may be
          stabilized rapidly in process.

    2  Geographic factors control rate of flow
       to the plant and mixing or  stabilization
       en route.  A given  slug discharge may
       not be  detectable if it enters the  collec-
       tion system at  a point  where it can be
       dispersed among other contributions.

       a  Smaller collection systems emphasize
          both variability  and effects of single
    3  A given channel flow may include solids
       movement along the bottom and floatable
       materials at the surface.  A  sample of
       this flow contains variable proportions
       of both depending upon turbulence at
       the sampling site.

    4  Contributing population activities are
       scheduled by working,  eating, sleeping,
       weather, TV,  and other influences.
       Wastewater load varies accordingly
       with the time of the day,  week or month.

 B  The plant functions as an  equilization basin
    as well as a processing facility.

    1  A given slug discharge is dispersed
       among liquids  already  in process.

    2  It may require several hours to traverse
       various process units.  Plant perform-
       ance sampling at the inlet and outlet
       at a given time is likely to represent
       different process loads or conditions.

    3  Changing conditions within the plant
       affect determinability of certain analy-
       tical criteria in process.

       a  An influent and effluent BOD involve
          different progressions.
 V  Treatment plant sampling preferably
 should be designed to show what has been
 done during the operation and what remains
 to be done.

 A  Integrity of the sampling  program is deter-
    mined by the comparisons between actual
    performance and reported performance.

    1  Treatment plant loading includes
       that into process

    2  The discharged flow includes treated,
       by-passed, or process return flows.

    3  Plant achievement reflects the differ-
       ence in material balance among incoming
       and outgoing process water contributions
       of nutrients, oxygen demand,  solids or
       other criteria.

This outline was prepared by  F. J. Ludzack,
Chemist, National Training Center,  Water
Quality Office, EPA,  Cincinnati, OH 45226.


 A The need for examination of sewage as it
   enters and leaves sedimentation tanks
   varies from plant to plant.  In deciding
   which tests are essential,  the operator
   must take into account the treatment units
   which follow,  such as trickling filters,
   aeration tanks,  intermittent sand filters,
   and sludge digestion and dewatering facilities.

 B Where the effluent is discharged to receiving
   waters without further treatment,  the
   operator  must select tests which will
   measure  the impact on the stream.

A Suspended and Settleable Solids

   1  Tests for settleable and suspended solids
      are used to measure the  effectiveness of
      sedimentation.  These tests should be
      made daily on composited samples at
      large plants and at least  twice weekly at
      smaller plants where laboratory work is

   2  Samples should be taken  of the influent
      and effluent of the tank at parts where
      the sewage is well mixed.

   3  Test results indicate the clarity of the
      effluent and the loading of suspended
      matter on the receiving waters or the
      biological treatment  units which may
      follow.  They also indicate the quantity
      of sludge to be treated and disposed of.

   4  Efficiency of solids removal by sedi-
      mentation can be  calculated from
      influent and effluent data.

B Biochemical Oxygen Demand

   1  The five-day biochemical oxygen demand
      test provides a good  measurement of
      sewage strength.
       Tests on composite samples of influent
       and effluent should be made daily and
       never less frequently than twice weekly,
       even in small plants.

       Tests on the tank effluent provide a
       good measure of the strength and
       quantity of the organic loading imposed
       on subsequent biological processes or
       on the receiving waters.

 A  Settleable Solids Test

    1  Sampling - Catch samples at period of
       maximum flow and if possible allow for
       the lag in time equal to the flow-through
       period of the settling tank.

    2  Equipment - Two Imhoff cones, one for
       influent and one for effluent.  These
       are large glass cones of one-liter
       capacity, the lower ends of which are
       graduated in milliliters (ml).  They
       should be cleaned with strong soap and
       hot water, using a brush.  Wetting of
       the cone with water before use helps to
       prevent adherence of the solids to the
       sides.  A wooden rack or  shelf should
       be provided to hold  the cones.

    3  Procedure

       a A measured quantity of well-mixed
         sample,  usually one liter, is gently
         poured into the cone and allowed to
         stand for a total period of one hour.

       b After the sample has stood forty-five
         minutes, gently rotate the cone
         between the hands so as to loosen  the
         solids that adhere to the sides.

       c Allow to settle fifteen minutes  longer.

       d Read from the graduations the  volume
         of solid material deposited in the
         cone making allowances for any
 PC.WAS.6. 11.68

Determining Efficiency of Settling Tanks and Clarifiers
        unfilled portions of the cone below
        the level of the settled solids.

   4  Results are expressed as ml of solids
      per liter which settled in one hour.
     ml of solids X
                    ml of sample

      ml of settleable solids per liter
      If the samples represent the influent and
      effluent of a tank, the efficiency of the
      tank may be found.
      ml of solids per , .  ml of solids per
      liter of influent     liter of effluent
      ml of solids per liter of influent
X 100
        percent of settleable solids removed

B  Suspended Solids Test

   1  Sampling - The same samples that were
      collected for the settleable solids test
      should be used for this test, or preferably,
      an integrated sample adequately

   2  Equipment  - Gooch crucibles, a filter
      flask with fittings, aspirator filter pump,
      drying oven, desiccator, analytical
      balance with weights, graduated cylinder
      (100 ml), washed and ignited medium
      asbestos fibre,  and a gas burner with
      tripod and triangles or an electric
      muffle furnace.

   3  Procedure
        Prepare a suspension of 15 grams of
        medium asbestos fibre in 1000 ml of
        distilled water and pour a portion
        through the Gooch crucible in the
        filter flask to make a mat about one-
        eighth inch thick.
c Wash with 100 ml distilled water.

d Dry crucible with mat in oven at

e Ignite crucible and mat in muffle
  furnace or over gas burner.

f Cool in desiccator and weigh.

g Again place crucible in filter flask
  and pour a measured amount of the
  well-mixed sample into the crucible
  and filter it through.  Filtration is
  faster if sample  is added in  small
  increments.   For settled sewage  or
  plant effluents,  larger portions
  should be used.

h Rinse the graduated cylinder with
  distilled water and pour through the

i Dry the crucible in the oven for one
  hour at 103<>C.

j Cool in desiccator and weigh.

Results are expressed as parts per
million (ppm).  The difference between
the  weight of the crucible before
filtering and the weight of the crucible
after filtering is the weight in grams
of the total suspended solids.
          weight .of suspended      1, OOP, OOP
           solids in grams        ml of sample

               ppm total suspended  solids
             If the samples represent the influent
             and effluent of a tank,  the efficiency
             of removal of suspended material can
             be calculated.
        Carefully remove the mat with a
        spatula or tweezers.  Invert and
        replace in the Gooch crucible.
    mg of suspended solids ,_. mg of suspended solids
    per liter of influent	per liter of effluent
       mg of suspended solids per liter of influent
      X 100  =  percent of suspended solids removed

                                       Determining Efficiency of Settling Tanks and Clarifiers
     Sampling - The samples which represent
     the influent and effluent will require
     dilution depending upon the sewage

     Equipment and procedures for conducting
     the test are considered in subsequent

     Efficiency  of BOD removal in the settling
     tanks can be  calculated from the influent
     and effluent data.

Manual of Instruction for Treatment Plant
   Operators, Distributed by Health
   Education Service,  P.O. Box 7285,
   Albany, New York  12224.
Operation of Wastewater Treatment Plants,
   WPCF Manual of Practice #11, Water
   Pollution Control Federation,  Washington,
   D.C.,  (1966).

This outline was prepared by D. S.  May,
Microbiologist,  FWQA  Training Activities,


A  Sludge digestion is essentially a biochemical
   process and a rather involved one. Its
   effective management and control require
   frequent observations of the raw,  inter-
   mediate, and end products unless the
   facilities greatly exceed present needs and
   all other plant processes are so well
   regulated that even poor operation of the
   digester would overcome these deficiencies.
   Such a combination of circumstances
   seldom  exists.

B  In deciding what measurements and tests
   are essential and desirable for his needs,
   the operator must take into account the
   variability of the quantity and quality of the
   raw sludge,  the  kind and number of units
   in the digester system,  and the acceptable
   range of quality  of the digested sludge and
   supernatant.   If  sludge gas is utilized for
   heat or  power, its volume and components
   become important.

C  When  satisfactory digestion is in progress,
   the following measurements and tests are
   most useful to determine loading on the
   digester units, departures from normal
   values,  progress of  digestion, quality of
   digested sludge and  supernatant,  effect on
   other  plant units, trends in over-all
   performance,  and reserves for unusual
   circumstances and future growth.

   1 Sludge in digester

     a  Temperature

     b  pH

     c  Percent volatile matter

     d  Volatile acids

     e  Bicarbonate, alkalinity, ammonia,
        or other  alkalinity

     f  Physical characteristics
      g Quantity transferred to other digesters

      h Gas production

      i Gas components

   2  Digested sludge withdrawn

      a Physical characteristics

      b Volume removed

      c Total and volatile solids

      d pH

   3  Supernatant

      a Volume removed

      b pH

      c Volatile acid/alkalinity ratio

      d Suspended solids

      e BOD


 A Samples and measurements of digesting
   sludge should be analyzed with sufficient
   frequency to determine

   1  The progress of digestion

   2  Reasons for unusual performance

   3  When to withdraw sludge

   4  Needed changes in controls

 B Sampling of Sludge

   1  As in the case of sewage,  the value of
      sludge analyses depends largely upon
      the accuracy of sampling.  Thus it is
      necessary to observe strict pre-
      cautions in the selection of sampling

Testing as a Tool for Digester Operations
     points and methods of sampling to insure
     the collection of representative samples
     at all times.

   2 To collect samples of sludge from
     different depths in a tank, a sampling
     apparatus  can be used that is made of
     cast iron or brass weighted  with lead.
     It can be lowered  into the tank by a link
     chain which carries markings  showing
     the various depths.  The apparatus is
     fitted with valves  operated by a cord.
     A pull on the cord at the  desired depth
     opens the valves and the  sludge flows
     in at the bottom while air escapes at
     the top.

   3 A wide-mouth stoppered  bottle attached
     to the end  of a pole can also be used.
     The bottle is pushed to the desired depth
     and the stopper removed by  means of an
     attached cord.

   4 Many sludge digesters are equipped with
     sampling taps at various depths.  Care
     must be taken to insure that the lines
     are freed of accumulated sludge before
     the sample is taken.

C  Temperature

   1 The temperature of the digesting sludge
     should be recorded so that both short-
     and long-term fluctuations and trends
     may be observed and recorded at various
     levels in the unit.

   2 Severe fluctuations in temperature may
     drastically affect  the operation of the
D  pH
     The pH is a valuable indicator of
     conditions but volatile acid/alkalinity
     relations are more valuable for  control

     The organisms which bring about
     anaerobic decomposition of organic
     materials have an optimum activity
     pH range of from 6. 8 to 7.2 usually
     signifying an acid/alkalinity ratio less
     than 0.5/1.0.
   3 Low pH indicates excessive production
     of organic acids.

   4 High pH indicates insufficient feeding
     or essentially complete digestion.

   5 Ordinarily,  the acid/alkalinity ratio of
     the digesting sludge need not be
     measured more often than once weekly
     unless unstable or unfavorable conditions
     are developing in the digester.

E  Percent Volatile Matter

   1 This is the best indicator of the progress
     of digestion.

   2 When the  test is performed on samples
     for inventory purposes,  the results
     provide an excellent indication of the
     suitability for withdrawal for
     dewatering and disposal.

   3 When performed on  samples of
     materials transferred from the first
     to the  second-stage  digester,  the test
     results give an excellent indication of
     the amount of digestion required in the
     second stage.

   4 Ordinarily,  samples would be  collected
     at the  same frequency and for  the same
     reasons as outlined  for pH.

F  Volatile Acids

   1 This test  has gained in popularity in
     recent years.  It provides an excellent
     indication of the progress of digestion
     and many forecast possible future
     trouble when considered as a ratio of
     its alkaline equivalent.

   2 It should be performed at about the
     same frequency as pH.

   3 During the acid stage of digestion,
     volatile acids may reach levels of
     several thousand mg/1; a completely
     digested sludge and  good supernatant
     will fall well below 300.

                                                  Testing as a Tool for Digester Operations
G  Bicarbonate Alkalinity

   1 This test is found by some operators to
     be very valuable in determining the
     progress of digestion.

   2 Normal range for well-digested sludge
     2000 to 5000 mg/1.

   3 The ratio of acid to alkali is an estimate
     of buffer capacity of digester contents
     and resistance to changes due to rapid
     or excessive loads of acid producing
     feeds.   A new feed rapidly contributes
     to production of acids which if excessive
     will cause a marked release of CO  to
     the gas phase and concurrent decrease
     in alkalinity.  Acid to alkalinity ratios
     may be less than 0. 1/1.0 after good
     digestion.  A major pH decrease is
     unlikely until the ratio is above 0.5/1.0.

H  Physical  Characteristics

   1 Physical characteristics of digesting
     sludge often give the operator a good
     indication of the progress of digestion.

   2 Color,  texture, and odor change
     markedly.  Each sample collected  for
     laboratory tests  should be examined

I   Volume Transferred

   1 The volume of partially or wholly
     digested sludge transferred from one
     digester to another or removed for
     dewatering or disposal  should be
     estimated and recorded.
    2  Falling gas production may indicate
       either reduction in rate of digestion
       or that digestion has proceeded to the
       point where removal of digested sludge
       is overdue.  This frequently is the first
       indication of the presence of a toxic

    3  Sharp increases in gas production may
       indicate over feeding, restoration of
       favorable  conditions after an upset, or
       establishment of good operations after
       startup.  Acid/alkalinity relations
       should be  checked.

 K Gas Components

    1  Tests for  methane,  carbon dioxide,
       hydrogen,  and hydrogen sulfide assist
       the operator in  determining the cause
       of poor burning characteristics of the
       gas and the progress of digestion.
       These tests are not performed routinely.
       Information so obtained is most useful
       where the gas is used in engines.

    2  When the gas contains more than 40
       percent carbon  dioxide, it may not burn.
       This  high  CO. content is usually
       accompanied  oy poor digestion and may
       lead to foaming, usually resulting from
       lack of proper balance among  food
       supply, temperature,  and digestion
       time. Normal  CO? content of the gas
       ranges from 20 to "30% and is the most
       common and useful  check among
       operating  personnel.
   2 This data is used to determine loadings
     on other units and for calculation of
     work performed by the unit from which
     it is transferred.

J  Gas Production

   1 The quantity of gas produced during
     digestion in each digester should be
     measured continuously and the total
     recorded daily.  Departure from normal
     values should be investigated and
     compared with the results from other
     laboratory tests and known facts for
     control purposes.
    Before withdrawing sludge for dewatering
    on drying beds,  tests should be made to
    determine completeness of digestion.
    These tests are the basis for deciding
    whether chemicals such as alum are
    needed for conditioning as an aid to
    dewatering on drying beds.

    Tests and measurements made during
    withdrawal are valuable for determining
    the load on the drying beds and are needed
    for calculating the sludge balance in the
    digester and the work done by the digestion

 Testing as a Tool for Digester Operations
C  Physical Characteristics

   1 The sludge should be examined for color,
     texture,  and odors.

   2 These are excellent indicators of the
     extent of digestion.

D  Volume  Removed

   1 The volume removed should be calculated
     and recorded to assist in figuring digester
     inventories and checking the amount of
     total and volatile solids  removed from
     the system.

   2 The quantity removed may be estimated
     readily by calculating the volume of the
     beds occupied.

E  Total Solids

   1 The concentration of the sludge,  as
     measured by total solids content,
     indicates the extent  to which the  sludge
     has given up its "bound" water.  It also
     indicates the extent  of compaction and

   2 If other tests indicate that digestion is
     reasonably complete, but moisture
     content is high, more time may be needed
     for quiescent settling to improve
     separation and compaction.

F  Percent Volatile Matter

   1 Cell mass initially about 90% volatile
     may be digested to about 40% volatile
     after  extended  treatment.  Operating
     practice usually does not result in this
     magnitude of reduction.  Acceptable
     digestion usually results in 1/4 to 1/3
     lower volatile percentage than that in
     the feed.

G  pH

   1 The pH of the digested sludge should be
     close to  7.0.

   2 Sludge with a much  lower value is not
     ready for dewatering.

 A The quality of supernatant in the digesters
    should be determined before it is trans-
    ferred to the other treatment processes.
    If this is done, the zone of the  best quality
    supernatant may be located and adjustments
    can be made in points of discharge,
    quantities, and time periods to reduce
    adverse effects  in other plant units.  Also,
    with floating-cover tanks,  supernatant
    withdrawals usually can be deferred for

 B Volume Removed

    1  Quantity removed should be  observed
       and recorded as a basis for  determining
       pounds of total solids and volatile
       matter removed from one plant unit
       and added to another.

    2  Normally, it  is best to remove
       supernatant at a very low rate to
       minimize disturbance at the  source
       and to minimize the  effect of shock
       loading on the receiving unit.

 C pH and A cid/Alkalinity Relations

    1  These tests have value as a  guide of
       digester conditions.   It also helps the
       operator to decide whether to change
       the point of discharge so that it will
       not disrupt later treatment.

    2  Supernatant with an extremely low or
       high pH ordinarily would not be dis-
       charged to an activated sludge tank or
       trickling filter except at very low rates,

    3  Supernatant samples are easier to
       collect and test than digested sludge,
       and for this reason they are  relied on
       to give information on the general
       state  of sludge digestion.

 D Suspended Solids

    1  This test is useful in determining the
       concentration and quantity (when
       coupled with  quantity of flow) of
       suspended solids loading on receiving

                                           Testing as a Tool for Digester Operations
This is particularly important when          REFERENCES
the supernatant is returned to settling
and aeration tanks.                          1 Manual of Instruction for Treatment Plant
                                                 Operation, Health Education Service,
The concentration is indicative of the              P.O. Box 7285, Albany, New York 12224.
extent of separation and compaction of
the sludge.                                  2 Operation of Wastewater Treatment Plants,
                                                 WPCF Manual of Practice #11 and #16,
                                                 Water Pollution Control Federation,
                                                 Washington, D. C., (1966).
                                            This outline was prepared by D.S. May,
                                            Microbiologist, FWPCA Training Activities,


 A  Defined from a sanitary viewpoint, it is the
    contamination of water with excreta from
    the gut of warm blooded animals (humans,
    domesticated animals or wild animals.)

 B  A comprehensive definition of pollution is
    the addition of something to water which
    changes its natural qualities.
                              Ill  TYPES OF MICROORGANISMS
                                  OCCURRING IN SURFACE WATERS

                               A  Harmless Bacteria

                                  1  Sanitary significance as pollution

                                     a  Coliform group

                                     b  Fecal Streptococcus; and
 The sanitary definition emphasizes only the
 possible hazard of disease while the com-
 prehensive definition provides for the protec-
 tion of the  sources of water.
                                     c  Clostridium Perfringetis (anaerobic
                                        spore producer)

                                  2  Without sanitary significance as
                                     pollution indicators:

                                     a  Fluorescent species;
Domestic and
Wild Animals
privies &
septic tanks
          Bacterial Load
          Organic Material (Bacterial food)
          Disease Producing Species
          Indicator Microorganisms

          Surface Waters   •»	
                                 Chemical Wastes
                                 Industrial Wastes
                                 Organic and Inorganic Compounds
                                      Which May Affect Growth,
                                      Death or Survival of Bacterial

Significance of Bacteriologic Data
      b  Chromogenic bacteria (violet, red,
         yellow,  green,  etc.);

      c  Proteus group;

      d  Spore-producing rods (aerobic and
         anae robic);

      e  Achromobacter;

      f  Spirillium species;

      g  Coccus forms in chains,  clumps or
         packets; and

      h  Nuisance organisms (slime, iron
         and sulfur bacteria)
B  Pathogenic Species Which May be Present:

   1  Salmonella species (typhoid fever,
      various fevers or food poisoning);

   2  Shigella species (bacilliary dysentery);

   3  Brucella species (Brucellosis - usually
      Malta fever in man and contagious
      abortion in some domestic animals);

   4  Vibrio choleras  (cholera in tropical
      countries or backward areas);

   5  Bacillus anthracis (anthrax in animals
      and man);

   6  Mycobacterium (human and animal
      tuberculosis) tuberculosis

   7  Leptospira species (Leptospirosis in

      dogs,  cattle, swine,  rats, skunks,
      opossium,  raccoon and man)

   8   Viruses (Viral diseases in man and
      other animals);

   9   Endamoebahistolytica (dysentery - more
      common in hot climates);

 10   Parasites (various parasitic diseases
      in man and animals)

  A  Epidemics of waterborne origin: explosive
     outbreak of disease in large numbers of
     individuals due to the accidental pollution
     by fecal pathogens of a water ordinarily

  B  Sporadic waterborne disease: occasional
     cases due to rash individuals consuming
     known polluted water.

  A  Methods are qualitative rather than
     quantitative procedures;

  B  Procedures fail to detect pathogenic or-
     ganisms present in low densities;

  C  A variety of procedures and media required
     for examination of each water sample;

  D  Consumers of water would be infected before
     results of pathogenic tests were known (48
     hours or longer);

  E  Negative test  results with methods current-
     ly available would not insure safe water
     supply; and

  F  Failure to demonstrate pathogenic bacteria
     would not differentiate between a safe water
     (no fecal pollution) and a potentially unsafe
     supply (containing fecal pollution.)

     For the above reasons, routine testing of
     a water for pathogenic organism would not
     be applicable  for the determination of safe
     waters nor evaluation  of water quality for
     sanitation.  The pathogenic microorganisms
     are excluded from the group of pollution
     indicators although it is their occasional
     presence that  produces waterborne
     diseases or epidemics.

 An "Indication of Pollution" is defined as any
 microorganism which is always present in

                                                        Significance of Bacteriologic JPata_
   human or animal wastes; always found in nature  IX  METHODS OF DETECTION
   where enteric pathogenic bacteria are present;
   and by its absence excludes the probability of
   the presence of enteric pathogenic bacteria.
   This ideal indicator has not been found.   How-
   ever, the coliform group is a practical and
   usable indicator of pollution of water.
The coliform group is quantitatively measured
by a number of procedures, such as:

A  Membrane filter test using a differential

   A  Advantages

      1  Always present in feces and domestic

      2  Relatively easy to detect,

      3  Absence excludes the presence of enteric
         pathogens in a natural water,

      4  Presence indicates the possibility of
         enteric pathogenic organisms appearing
         at any time; and,

      5  Density increases with increasing fecal
   B  Disadvantages

      1  Bacterial species conforming with
         official definition may be derived from
         sources other than fecal pollution,

      2  Coliform bacteria may grow in streams,
         etc.; and,

      3  Recency of pollution cannot be estimated
         with measurable accuracy.

   The coliform group consists of aerobic and
   facultative anaerobic gram-negative rods,
   not producing spores and fermenting lactose
   with gas production within 48 hours at  35°C.
B  Multiple tube procedure which measures
   the most probable number present on a
   statistical basis; and

C  Direct plate count using a differential
   medium (where coliform density exceeds
   10 coliforms per ml.)
The magnitude of the coliform density will
vary with the type of test procedure used.
It will also vary within a single procedure
unless identical methods are  used with media
of uniform bacterial productivity.  This in-
dividual variability of results makes compari-
son of tests on the same sample difficult but
does not  affect the interpretation nor the
sanitary  significance of the coliform data.

The delayed incubation MF test is a modifi-
cation of the MF procedure for coliform
which permits holding the bacterial on a mem-
brane several days before making the final
incubation and enumeration.  Extensive field
tests indicate  relatively good correlation
between the two MF procedures with  the same
interpretation of sanitary significance and
water quality classification as  obtained from
the completed MPN test.

Numerical variation does occur between the
MF tests and MPN test,  or, to a lesser extent,
between the immediate and delayed MF tests.
Where such disagreements are of sufficient
difference to  have numerical  significance,
it  is necessary to make  detailed bacterial

   Significance of Bacteriologic Data
   studies  to determine which method
   yields the most accurate result and the type
   of bacterial flora responsible  for failure of
   the  MF  or MPN procedures.

   The delayed incubation MF procedure will
   measure changes occurring in the coliform
   density at each sample location on a weekly
   basis. Increases or decreases are in turn
   related to quantity of fecal pollution entering
   the stream.  The probability of pathogenic
   organisms being present may be presumed to
   increase with increasing coliform densities.

   By using a medium of uniform productivity and
   standardized test procedures,  the differences
   in results by months or years becomes  the
   measure of pollutional change,  without con-
   sideration of the absolute densities or statisti-
   cal errors characteristic to each of the accepted
   procedures for coliform detection and

   This comparison of data is best accomplished
   by calculating the logarithmic average or
   median by months,  by seasons and by each
   year.   Such data will permit the rapid com-
   parison of increasing or decreasing pollutional
   loads  by months, seasons or years and  the
   total coliform load by use of flow rates  inCFS
   (cubic feet per second)for each sample location.

   Since the  survival, growth or death rates  of
   the coliform group are characteristic for
   each location, extreme  caution  must be
   exercised in comparison of data from different

   A  Definition

      An exact  definition of the streptococci
      associated with fecal pollution has not
been agreed upon by the various authorities.
in the field.  A working definition used  by
the  Water Quality Studies laboratory of
this Center is:

"Fecal streptococcus are any species of
Streptococcus commonly present in signi-
ficant numbers in the fecal excreta of
humans or other warm-blooded animals. "
Fecal Streptococcus as Pollution

1  Advantages of fecal streptococci as
   pollution indicators

   a  They are present in feces and

   b  They are not found in pure waters or
      sites out of contact with human or
      animal life,  so far as is currently

   c  They are generally considered  not
      to multiply outside the human body
      (except in rich food materials such
      as milk, etc.)

   d  They are more resistant to elec-
      trolytes than most bacteria.

   e  They are considered to indicate
      fecal pollution when present.

2  Disadvantages of fecal streptococci as
   pollution indicators

   a  The streptococcus density in sewage
      or water is lower than the coliform

   b  Survival time in water has not been
      adequately determined in reference
      to the pathogenic enteric bacteria.

                                                        Significance of Bacteriologic Data
C  Methods of Detection

   The fecal  streptococci are quantitatively
   measured either by a multiple tube pro-
   cedure which measures the most probable
   number present on a statistical basis, or
   by a membrane filter test using a differential
   medium.   In addition,  direct plate count
   methods may be employed using a
   differential medium (where fecal strep-
   tococcus density exceeds 10 per ml.)
   useful supplemental indicator where the
   coliform data may be subject to doubt or
   denied as to fecal origin.  The fecal
   streptococcus group may have little
   value in the examination of treated water
   supplies  but have useful application in
   stream pollution investigations, evaluation
   of degree of pollution in certain types of
   surface water,  examination of swimming
   pools or  similar uses.
D  Current Status

   The fecal streptococcus group is recognized
   as a tentative test procedure in the 12th
   Edition of Standard Methods, APHA 1965.
   The characteristics and distribution of this
   group in nature suggest it would be a most
This outline was prepared for the Training
Program by the late Harold F. Clark,
Microbiologist, and updated by Rocco
Russomanno, Microbiologist.

                            FECAL STREPTOCOCCUS GROUPS
                          (Multiple Dilution Tube (MPN) Methods)
B  Part 2
The  subject matter of this outline is contained
in three parts, as follows:

A  Part 1

   1  Fundamental aspects of multiple dilution
      tube ("most probable numbers") tests,
      both from a qualitative and a quantitative

   2  Laboratory bench records.

   3  Useful techniques in multiple dilution
      tube methods.

   4  Standard supplies, equipment,  and
      media in multiple dilution tube tests.
   Detailed, day-by-day, procedures in tests
   for the coliform group and subgroups
   within the coliform group.

C  Part 3

   Detailed, day-by-day, procedures in tests
   for members of the fecal streptococci.

D  Application of Tests to Routine Examinations

   The following considerations (Table 1) apply
   to the selection of the Presumptive Test,
   the Confirmed Test,  and the Completed
   Test.  Termination of testing at the
   Presumptive Test level  is not  practiced
   by laboratories of this agency. It must
   be realized that the Presumptive  Test alone
   has limited use when water quality is to
   be determined.
                                          TABLE 1
                              Examination Terminated at -
Type of Receiving
Sewage Receiving
Treatment Plant - Raw
Other Information
Not Done
Not Done
Not Done

Confirmed Test
Applicable in all
cases where Pre-
sumptive Test alone
is unreliable.
Completed Test
Important where results
are to be used for control
of raw or finished water.
Application to a statis-
tically valid number of
samples from the
Confirmed Test to estab-
lish its validity in
determining the sanitary
quality .
NOTE:  Mention of commercial products and manufacturers does not imply endorsement by the
        Environmental Protection Agency.

      MPN Methods

 A  Qualitative Aspects

    1  For purely qualitative aspects of testing
      for indicator organisms, it is convenient
      to consider the tests applied to one
      sample portion, inoculated into a tube
      of culture medium, and the follow-up
      examinations and tests on results of the
      original inoculation.  Results of testing
      procedures are definite: positive
      (presence of the organism-group is
      demonstrated) or negative  (presence of
      the organism-group is not  demonstrated.)

    2  Test procedures are based on certain
      fundamental assumptions:

      a  First,  even if only  one living cell of
         the test organism is present in the
         sample, it will be able to grow when
         introduced into the  primary inoculation

      b  Second, growth of the test organism
         in  the culture medium will produce
         a result which indicates presence of
         the test organism; and,

      c  Third, extraneous organisms will
         not grow,  or if they do grow, they
         will not limit growth of the test
         organism; nor will  they produce
         growth effects that  will be confused
         with those of the bacterial group for
         which the test is designed.

    3  Meeting these assumptions usually
      makes it necessary to conduct the tests
      in a series of stages (for example,  the
      Presumptive,  Confirmed, and Completed
      Test stages,  respectively, of standard
      tests  for the coliform  group).

    4  Features of a full, multi-stage test

      a  First stage:  The culture  medium
         usually serves primarily  as an
         enrichment medium for the group
         tested.  A good first-stage growth
         medium should support  growth of all
         the living cells of the group tested,
         and it should include provision for
         indicating the presence of the test
   organism being studied.  A first-
   stage medium may include some
   component which inhibits growth
   of extraneous bacteria, but this
   feature never should be included
   if it also inhibits growth of any
   cells of the group for which the
   test is designed.  The Presumptive
   Test for the coliform group is a
   good example.  The medium
   supports growth, presumably, of
   all living cells of the coliform
   group; the culture container has a
   fermentation vial for demonstration
   of gas production resulting from
   lactose fermentation by coliform
   bacteria, if present; and  sodium
   lauryl sulfate may be included in
   one of the approved media for
   suppression of growth of  certain
   noncoliform bacteria.  This
   additive apparently has no adverse
   effect on growth of members  of the
   coliform group  in the concentration
   used.  If the result of the first-stage
   test is negative, the  study of  the
   culture is terminated, and the result
   is recorded as a negative test.  No
   further study is made of negative
   tests.  If the result of the first-
   stage test is positive, the culture
   may be subjected to further study
   to verify the findings of the first

b  Second stage:  A transfer is made
   from positive cultures  of the first-
   stage test to a second culture medium.
   This test stage emphasizes provision
   to  reduce confusion of results due to
   growth effects of extraneous  bacteria,
   commonly achieved by addition of
   selective inhibitory agents.   (The
   Confirmed Test for coliforms meets
   these requirements. Lactose and
   fermentation vials are  provided for
   demonstration of coliforms in the
   medium.  Brilliant green dye and
   bile salts  are included as inhibitory
   agents which tend to suppress growth
   of  practically all kinds of noncoliform
   bacteria,  but do not suppress growth
   of  coliform bacteria when used as

                                                                 MPN Methods
         If result of the second-stage test is
         negative, the study of the culture is
         terminated, and the result is re-
         corded as a negative test.  A negative
         test here means that the positive
         results  of the  first-stage test were
         "false positive, " due to one or more
         kinds of extraneous bacteria. A
         positive second-stage test  is partial
         vertification of the  positive results
         obtained in the first-stage  test; the
         culture may be subjected to final
         identification through application of
         still further testing procedures.  In
         routine practice,  most sample exami-
         nations are terminated at the end of
         the second stage, on the  assumption
         that the  result would be positive if
         carried to the third, and final
         stage.  This practice should  be
         followed only if adequate testing is
         done to demonstrate that the  assump-
         tion is valid.  Some workers recom-
         mend continuing at least  5% of all
         sample examinations to the third
         stage to demonstrate the reliability
         of the second-stage results.

B  Quantitative Aspects of Tests

   1  These methods for determining bacterial
      numbers are based on  the assumption
      that the bacteria can be separated from
      one another (by shaking or other means)
      resulting in a suspension of individual
      bacterial cells, uniformly distributed
      through the original sample  when the
      primary inoculation is  made.

   2  Multiple dilution tube tests for quantita-
      tive determinations apply a  Most Probable
      Number (MPN)  technique.   In  this pro-
      cedure one  or more measured portions
      of each of a stipulated series of  de-
      creasing sample volumes is inoculated
      into the first-stage culture medium.
      Through decreasing the sample  incre-
      ments,  eventually a volume  is reached
      where only one  cell is introduced into
   some tubes,  and no cells are introduced
   into other tubes. Each of the several
   tubes of sample-inoculated first-stage
   medium is tested independently,
   according to the principles previously
   described, in the qualitative aspects
   of testing procedures.

3  The  combination of positive and
   negative results is used in an application
   of probability mathematics to secure
   a single MPN value for the sample.

4  To obtain MPN values,  the following
   conditions must be met:

   a  The testing procedure must result
      in one or more tubes in which the
      test organism ^s demonstrated to
      be present; and

   b  The testing procedure must result
      in one or more tubes in which the
      test organism is not  demonstrated
      to be present.

5  The MPN value for a given sample is
   obtained through the use of MPN Tables.
   It is emphasized that the precision of
   an individual MPN value is not great
   when compared with most physical or
   chemical determinations.

6  Standard practice in water pollution
   surveys conducted by this organization,
   is to plant five tubes in  each  of a series
   of sample increments,  in sample
   volumes decreasing at decimal intervals.
   For example,  in testing known polluted
   waters,  the initial sample inoculations
   might consist of 5 tubes each in volumes
   of 0.  1, 0.01,0.001, and 0.0001 ml,
   respectively.  This series of sample
   volumes will yield determinate results
   from a low of 200 to a high of 1, 600, 000
   organisms per 100 ml.


 A Features of a Good Bench Record Sheet

    1  Provides complete identification of the

    2  Provides for full, day-by-day informa-
       tion about all tests performed on the

    3  Provides easy step-by-step record
       applicable  to any portion of the sample.

    4  Provides for recording of the quantitative
       result which will be transcribed to sub-
       sequent reports.

    5  Minimizes the amount of writing by the

    6   Identifies the analyst(s).
  B There is no such thing as "standard"
    bench sheet for multiple tube tests; there
    are many versions of bench sheets.  Some
    are prescribed by administrative authority
    (such as the Office of a State Sanitary
    Engineer); others are devised by laboratory
    or project personnel to meet specific needs.
     It is not the purpose of this discussion to
     recommend an "ideal" bench form; however,
     the form used in this training course
     manual is essentially similar to that used
     in  certain research laboratories of this
     organization.  The student enrolled in the
     course for which this manual is written
     should make himself thoroughly familiar
     with the bench sheet and its proper use.
     See Figure 1.

 A Each bacteriological examination of water
    by multiple dilution tube methods requires
    a considerable amount of manipulation;
    much is quite repetitious.  Laboratory
    workers must develop and maintain good
    routine working habits, with constant
    alertness  to guard against lapses into
    careless,  slip-shod laboratory procedures
    and "short cuts" which only can lead to
    lowered quality of laboratory work.

    The student reader is urged to review  the
    form for laboratory surveys  (PHS-875,
    Rev. 1966) used by Public Health Service
    personnel charged with responsibility for
    accreditation of laboratories for examination
    of water under Interstate Quarantine

 B Specific attention is brought to the following
    by no means exhaustive, critical aspects of
    laboratory procedures in multiple  dilution
    tube tests:

    1  Original sample

       a  Follow  prescribed care and handling
         procedures before testing.

       b  Maintain absolute identification of
         sample at all stages in testing.

       c  Vigorously shake samples (and
         sample dilutions) before planting
         in culture media.

    2  Sample measurement into primary
       culture medium

      a  Sample portions must be measured
         accurately into the culture medium
         for reliable quantitative tests to be
         made.  Standard Methods prescribes
         that  calibration  errors should not
         exceed  + 2.5%.


                                                     Multiple Dilution Tube Tests
              Sample Station
Collection Data

Date A/b/t,?   Time f.-£0     By
Temperature    P °C         pH_^5
Other Observations
  MPN Methods
       Suggested sample measuring practices
       are as follows:  Mohr measuring
       pipets are recommended.  10 ml
       samples are delivered at the top of
       the culture tube, using 10 ml pipets.
       1.0 ml samples are delivered down
       into the culture tube, near the sur-
       face of the medium, and "touched
       off" at the side of the tube when the
       desired amount of sample has been
       delivered.   1. 0 ml or 2. 0 ml pipets
       are used for measurement of this
       volume. 0. 1 ml samples are
       delivered in the same manner as 1. 0
       ml samples, using great care that
       the sample actually gets into the
       culture medium.  Only 1. 0 ml pipets
       are used for this sample volume.
       After delivery of all sample incre-
       ments into the culture tubes,  the
       entire rack of culture tubes may be
       shaken gently to carry down any of
       the sample adhering to the wall of
       the tube above the medium.

       Workers should demonstrate by actual
       tests  that the pipets and the technique
       in use actually delivers the rated volumes
       within the prescribed limits of error.
       Volumes as small as 0. 1 ml routinely
       can be delivered directly from the
       sample with suitable pipets.   Lesser
       sample volumes first should be diluted,
       with subsequent delivery of suitable
       volumes of diluted sample into the
       culture medium. A diagrammatic
       scheme for making dilutions is shown
       in Figure 2.
 b  Gas in any quantity is a positive test.
    It is necessary to work in conditions
    of suitable lighting for easy recog-
    nition of the extremely small amounts
    of gas inside the tops of some
    fermentation vials.

 Reading of liquid culture tubes for
 growth as indication of a positive test
 requires good lighting.  Growth is
 shown by any amount of increased
 turbidity or opalescence in the culture
 medium, with or without deposit of
 sediment at the bottom of the tube.

 Transfer of cultures with inoculation
 loops and needles

 a  Always sterilize inoculation loops
    and needles in flame immediately
    before transfer of culture; do not
    lay it down or touch it to any non-
    sterile object before making the

 b  After sterilization,  allow sufficient
    time for cooling, in the air, to avoid
    heat-killing bacterial cells  on the
    hot wire.

 c  Loops should be 3 mm in inside
    diameter,  with a capability of holding
    a drop of water or culture.

    For routine standard transfers
    requiring transfer of 3 loopsful of
    culture,  many workers form three
    3-mm loops on the same length of
    Reading of culture tubes for gas

    a  On removal from the incubator,
       shake culture rack gently, to
       encourage release of gas which
       may be supersaturated in the culture
As an alternative to use of standard
inoculation loops,  the use of
"applicator sticks" have now been
sanctioned by the 13th Edition of
Standard Methods.

                                                                        MPN Methods
            Dilution Ratios:
                        Figure 2.  PREPARATION OF DILUTIONS

      . 1 ml.
Delivery volume   10ml     1ml     O.lml     1ml    O.lml
               Petri Dishes or Culture Tubes
Actual volume     10 ml
of sample in tube
I0"2ml  I0"3ml
I0"4ml  I0"5ml
      The applicator  sticks are dry heat
      sterilized (autoclave sterilization is
      not acceptable because of possible
      release of phenols if the wood is
      steamed) and are used on a single-
      service basis.  Thus, for every culture
      tube transferred, a new applicator
      stick is used.

      This use of applicator sticks is
      particularly attractive in field
      situations where it is inconvenient or
      impossible to provide a gas burner
      suitable for sterilization of the
      inoculation loop.  In addition, use of
      applicator sticks is favored in
      laboratories where room temperatures
      are significantly elevated by  use of
      gas burners.
                         7  Streaking cultures on agar surfaces

                            a  All streak-inoculations should be
                               made without breaking the surface
                               of fae agar.   Learn to use a light
                               touch with the needle; however,
                               many inoculation needles are so
                               sharp that they are virtually useless
                               in this respect.  When the needle is
                               platinum or platinum- iridium wire,
                               it sometimes is beneficial to fuse
                               the working tip into a small sphere.
                               This can be done by momentary
                               insertion of a we 11-insulated (against
                               electricity) wire into a carbon arc,
                               or some other extremely hot environ-
                               ment.  The sphere should not be more
                               than twice the  diameter of the wire
                               from which it is formed, otherwise
                               it will be entirely too heat-retentive
                               to be useful.

  MPN Methods
      When the needle is nichrome
      resistance wire,  it cannot be heat-
      fused; the writer prefers  to bend
      the terminal 1/16 - 1/8" of the wire
      at a slight angle to the overall axis
      of the needle.  The side of the
      terminal bent portion of the needle
      then is used for inoculation of agar

   b  When  streaking for colony isolation,
      avoid  using too much inoculum.  The
      streaking pattern is somewhat
      variable according to individual
      preference.   The procedure favored
      by the writer is shown in the
      accompanying figures. Note
      particularly that when going from
      any one stage of the streaking to the
      next, the inoculation needle is heat-

    Preparation of cultures for  Gram

    a  The Gram stain always should  be
      made from a culture  grown on  a
      nutrient agar surface (nutrient agar
      slants are used here) or from nutrient
         The culture should be young, and
         should be actively growing.   Many
         workers doubt the validity of the
         Gram stain made on a culture more
         than 24 hours old.
         Prepare a thin smear for the staining
         procedure.  Most beginning workers
         tend to use too much bacterial sus-
         pension in preparing the dried smear
         for staining.   The amount of bacteria
         should be so small that the dried film
         is barely visible to the naked eye.

 Consolidated lists of equipment, supplies,
 and culture media required for all multiple
 dilution tube tests described in this outline
 are shown in Table 2..  Quantitative infor-
 mation is not presented; this is variable-
 according to the extent of the testing pro-
 cedure, the number of dilutions used, and
 the number of replicate tubes per dilution.
 It is noted that requirements for alternate
 procedures are fully listed and choices are
 made in accordance to laboratory preference.

                                                             MPN Methods
                     a  Flame-sterilize an inoculation needle and air-cool.

                     b  Dip the tip of the inoculation needle into the bac-
                        terial culture  being studied.
                     c  Streak the inoculation needle tip lightly back and
                        forth over half the agar surface,  as in (1),  avoid-
                        ing scratching or breaking the  agar surface.
                     d  Flame-sterilize the inoculation needle and air-cool.
                     a  Turn the Petri dish one-quarter-turn and streak the
                        inoculation needle tip lightly back and forth over one-
                        half the agar surface,  working from area (1) into one-
                        half the unstreaked area of the agar.
                     b  Flame-sterilize the inoculation needle and air-cool.
                   3  a  Turn the Petri dish one-quarter-turn and streak the
                        inoculation needle tip lightly back and forth over one-
                        half the agar  surface, working from area (2) into
                        area (3), the remaining unstreaked area.
                     b  Flame-sterilize the inoculation needle and set it aside.
                     c  Close the culture container and incubate as prescribed.
                       STREAK-PLATE TECHNIQUE
AREA 1  (Heavy inoculum)
AREA  3  (Isolated colonies]
                                                AREA  2
                                               (Moderate  growth)
                              APPEARANCE  OF  STREAK -  PLATE
                               AFTER  INCUBATION  INTERVAL

MPN Methods
                       FERMENTATION TUBE TESTS
Description of Item
Lauryl tryptose broth or Lactose
broth. 20 ml amounts of 1. 5 X
concentration medium. In 25 X 150 mm
culture tubes with inverted fermen-
tation vials, suitable caps.
Lauryl tryptose broth or Lactose
broth. 10 ml amounts of single
strength medium in 20 X 150 mm
tatlon vials, suitable caps.
Brilliant green lactose bile broth, 2%
in 10 ml amounts, single strength,
in 20 X 150 mm culture tubes with
suitable caps.
Eos in meihylene blue agar, poured
in 100 X 15 mm Pelri dishes
EndoAgar, poured in 100X15 mm
Nutrient agar slant, screw cap tube
Boric acid lactose broth, 10 ml
amounts of single strength medium
In fermentation tubes.
EC Broth, 10 ml amounts of single
strength medium in fermentation
tubes .
Formate riclnoleatc broth
Culture tube racks, 10X5 openings;
each opening to accept 25 mm dia-
meter tubes.
Plpeties, 10 ml. Mohr type, sterile,
in suitable cans.
Pipettes, 2 ml (optional). Morh type,
sterile, in suitable cans
Pipettes, 1 Q3 1, Mohr type, sterile
in metal suitable cans
Standard buffered dilution water,
sterile, 99-ml amounts in screw-
capped bottles.
Gas burner, Bunaen type
Inoculation loop, loop 3mm dia-
meter, of nichrome or platlnum-
Iridium wire. 26 B fc S gauge, in
suitable holder, (or sterile applicator.
Inoculation needle, nichrome, or
platinum-irldlum wire, 26 B & S
gauge, in Dutiable holder.
Incubator, adjusted to 35 + 0. 50 C
Waterbath incubator, adjusted to
« + 0.2°C
Waterbath incubator, adjusted to
44.5+ 0. 2°C.
Glass microscopic slides, . 1" X3"
Slide racks (optional)
Gram-stain solutions, complete set
Compound microscope, oil Immer-
sion lena. Abbe' condenser
Basket for discarded cultures
Container for discarded pipettes
Total Coliform Group













Fecal CoUforim;






(EC broth)







                                           Part 2


A  Tests Described

   1  Presumptive Test

   2  Confirmed Test

   3  Completed Test

   4  Fecal Coliform Test

B  Form of Presentation

   The Presumptive,  Confirmed, and
   Completed Tests are presented as total,
   independent procedures.  It is recognized
   that this form of presentation is somewhat
   repetitious,  inasmuch as the Presumptive
   Test is preliminary to the Confirmed
   Test, and both the Presumptive Test and
   the Confirmed Test are preliminary to the
   Completed Test for total coliforms.

   In using these procedures, the worker
   must know at the outset what is to be the
   stage at which the test is to be ended,  and
   the details of the procedures throughout,
   in order to prevent the  possibility of
   discarding gas-positive tubes before
   proper transfer procedures have been

   Thus, if the  worker knows that the test will
   be  ended at the Confirmed Test, he will
   turn at once  to Section HI, TESTING TO
   ignore Sections II and IV.

   The Fecal Coliform Test is described
   separately,  in Section V, as an
   adjunct to the Confirmed  Test and to the
   Completed Test.

 A  First-Day Procedures

    1  Prepare  a laboratory data sheet for
      the sample.  Record the following
      information:  assigned laboratory
      number,  source of sample, date and
      time of collection, temperature of the
      source, name of sample collector,
      date and  time of receipt of sample in
      the laboratory.  Also show the date
      and time of starting tests in the
      laboratory, name(s) of worker(s) per-
      forming the laboratory tests,  and the
      sample volumes planted.

    2  Label the tubes of lauryltryptose broth
      required for  the initial planting of the
      sample (Table 3) . The  label should
      bear three identifying marks.   The
      upper number is the identification of
      the worker(s) performing the test
      (applicable to personnel in training
      courses), the number immediately
      below is  the assigned laboratory num-
      ber,  corresponding with the laboratory
      record sheet. The lower number is the
      code to designate the sample volume
      and which tube of a replicate series is
 NOTE: Be sure to use tubes containing
 the correct concentrations of culture medium
 for the inoculum/tube volumes.  (See the
 chapter on media and solutions for multiple
 dilution tube methods or refer to the current
 edition of  Standard Methods for Water and
                                                                                    2 7-11

MPN Methods

Bench number
Volume & tube
Bench number
Volume & tube
Bench number
Volume & tube
Bench number
Volume & tube
Bench number
Volume & tube
Sample volume
Tubes with 10 ml
of sample
Tubes with 1 ml
of sample
Tubes with 0. 1 ml
of sample
Tubes with 0.01 ml
of sample
Tubes with 0.001 ml
of sample
                                                                     Typical Example
                                                                           A .
                               Lab. Worker

                              -Bench Number

                              "Sample Volume
                                                                  Tube of Culture Medium
   The labeling of cultures can be reduced by labeling  only the first tube of
   each series of identical sample volumes in the initial planting of the sample.
   All subcultures  from initial plantings should be labeled completely.
      Place the labeled culture tubes in an
      orderly arrangement in a culture tube
      rack,  with the tubes intended for the
      largest sample volumes in the front
      row, and those intended for smaller
      volumes in the  succeeding rows.
      Shake  the sample vigorously, approxi-
      mately 25 times,  in an arc of one foot
      within seven seconds and withdraw the
      sample portion  at once.

      Measure the predetermined sample
     volumes into the labeled tubes of lauryl
     tryptose broth,  using care to avoid
     introduction of any bacteria into the
     culture medium except those in the

     a  Use a 10 ml pipet for 10 ml sample
        portions,  and 1 ml pipets for portions
        of 1 ml or less.  Handle sterile pipets
        only near the mouthpiece, and protect
        the  delivery end from external con-
        tamination.   Do not remove the cotton
        plug in the mouthpiece as this is
        intended to protect the user from
        ingesting any sample.
      b  When using the pipet to withdraw
         sample portions,  do not dip the
         pipet more than 1/2 inch into the
         sample; otherwise sample running
         down the outside of the pipet will
         make measurements inaccurate.

   6  After measuring all portions  of the
      sample into their respective tubes of
      medium, gently shake the rack of
      inoculated  tubes to insure good mixing
      of sample with the culture medium.
      Avoid vigorous shaking, as air bubbles
      may be shaken into the  fermentation
      vials and thereby invalidate the test.

   7  Place the rack of inoculated tubes in the
      incubator at 35°  + 0.5OC for  24 +
      2  hours.

B  24-hour Procedures

   1  Remove the rack of lauryl tryptose
      broth cultures from the incubator,  and
      shake gently.  If gas is  about to appear
      in the fermentation vials, the  shaking
      will speed the process.

                                                                           MPN Methods
    2  Examine each tube carefully.  Record,
      in the column "24" under LST on the
      laboratory data sheet, each tube showing
      gas in the fermentation vial as a positive
      (+) test and each  tube not showing gas
      as a negative (-)  test.  GAS IN ANY

    3  Discard all gas-positive tubes of lauryl
       tryptose broth, and return all the gas-
       negative tubes to the 35°C incubator
       for an additional 24+2 hours.

 C 48-hour Procedures

    1  Remove the rack of culture tubes from
       the incubator,  read and record  gas
       production for each tube.

    2  Be sure to record all results under the
       48-hour LTB column on the data sheet.
       Discard all tubes.  The Presumptive
       Test is concluded at this point,  and
       Presumptive coliforms per 100 ml can
       be computed according to the methods
       described elsewhere in this manual.

 Note that the description starts with the
 sample inoculation and includes the
 Presumptive Test stage.  The Confirmed
 Test preferred in Laboratories of this agency is
 accomplished by  means of the brilliant
 green lactose bile broth (BGLB) and the
 acceptable alternate tests are mentioned
 in III F. In addition, the Fecal Coliform
 Test is included as an optional adjunct to
 the procedure.

 A First-Day Procedures

    1  Prepare a laboratory data sheet for the
       sample.  Record the following infor-
       mation: assigned laboratory number,
       source of sample,  date and time of
       collection,  temperature of the source,
       name of sample collector, date and
       time of receipt of sample in the
       laboratory.  Also show the date and
   time of starting tests in the laboratory,
   name(s) of worker(s) performing the
   laboratory tests,  and the sample
   volumes planted.

 2  Label the tubes of lauryl tryptose broth
    required for the initial planting of the
    sample.   The label should bear three
    identifying marks.   The upper number
    is the identification  of the worker(s)
    performing the test  (applicable to
    personnel in training courses),  the
    number immediately below is the
    assigned laboratory number,  corres-
    ponding with the laboratory record
    sheet. The lower number is the code
    to designate the sample volume and
    which tube of a replicate series is

   NOTE:  If 10-ml samples are being
   planted, it is necessary to use tubes
   containing the correct concentration
   of culture medium.  This has pre-
   viously been noted in II A-2.

3  Place the labeled culture tubes in an
   orderly arrangement in a culture tube
   rack,  with the tubes  intended for the
   largest sample volumes in the front
   row, and those intended for smaller
   volumes in the succeeding rows.

4  Shake the sample vigorously, approxi-
   mately 25  times, in an up-and-down

5  Measure the predetermined sample
   volumes into the labeled tubes of lauryl
   tryptose broth,  using care to avoid
   introduction of any bacteria into the
   culture medium except those in the

   a  Use a 10-ml pipet for 10 ml sample
      portions, and 1-ml pipets for portions
      of 1 ml or less.  Handle sterile pipets
      only near the mouthpiece, and protect
      the delivery end from external con-
      tamination. Do not remove the cotton  plug
      in the mouthpiece  as this is intended
      to protect the. user from ingesting
      any sample.

     MPN Methods
     b  When using the pipet to withdraw
        sample portions, do not dip the
        pipet more than 1/2 inch into the
        sample; otherwise sample running
        down the outside of the pipet will
        make measurements inaccurate.

     c  When delivering the sample into the
        culture medium, deliver sample
        portions of 1 ml or less down into
        the culture tube near the surface of
        the medium.   Do not deliver small
        sample volumes at the top of the tube
        and allow  them to run down  inside
        the tube; too  much of the sample
        will fail to reach the culture medium.

     d  Prepare preliminary dilutions of
        samples for portions of 0. 01 ml or
        less before delivery into the culture
        medium.  See Table 1 for preparation
        of dilutions.  NOTE: Always deliver
        diluted sample portions into the
        culture medium as  soon as possible
        after preparation.  The interval
        between preparation of  dilution and
        introduction of sample into the
        medium never should be as  much
        as 30 minutes.

   6  After measuring all portions of the
     sample into their respective tubes of
     medium,  gently shake the  rack of
     inoculated tubes to insure  good mixing
     of sample with the culture medium.
     Avoid vigorous  shaking,  as air bubbles
     may be shaken into the fermentation
     vials and thereby invalidate the test.

   1  Place the rack of inoculated tubes in
     the incubator at 35° + 0.5OC for 24 +
     2 hours.

B  24-hour Procedures

   1  Remove the rack of lauryl tryptose
     broth cultures from the incubator,  and
     shake gently. If gas is about to appear
     in the fermentation vials,  the shaking
     will speed the process.
Examine each tube carefully.  Record,
in the column "24" under LST on the
laboratory data sheet, each tube  showing
gas in the fermentation vial as a
positive (+) test and each tube not
showing gas as a negative (-) test.

Retain all gas-positive tubes of lauryl
tryptose broth culture in their place
in the rack, and proceed.

Select the gas-positive tubes of lauryl
tryptose broth culture for Confirmed
Test procedures.  Confirmed Test
procedures may not be required for all
gas-positive  cultures.  If, after 24-hours
of incubation, all five replicate cultures
are gas-positive for two or more con-
secutive sample volumes,  then select
the set of five cultures representing
the smallest  volume of sample in which
all tubes were gas-positive.  Apply
Confirmed Test procedures to all these
cultures and  to any other gas-positive
cultures representing smaller volumes
of sample, in which some tubes were
gas-positive  and some were gas-negative.

Label one tube of brilliant green lactose
bile borth (BGLB) to correspond with
each tube of lauryl tryptose broth
selected for Confirmed Test procedures.

Gently shake the rack of Presumptive
Test cultures.  With a flame-sterilized
inoculation loop transfer one loopful of
culture from each gas-positive tube to
the corresponding tube of BGLB. Place
each newly inoculated culture into BGLB
in the position of the original gas-positive

After making the transfers, the rack
should contain some 24-hour gas-
negative tubes of lauryl tryptose broth
and the newly inoculated BGLB.

If the Fecal Coliform Test is included
in the testing procedures,  consult
Section V of this part of the outline  of
testing procedures.

                                                                          MPN Methods
   9  Incubate the 24-hour gas-negative
      BGLB tubes and any newly-inoculated
      tubes of BGLB an additional 24 + 2
      hours at 35° + 0. 5°C.

C  48-hour Procedures

   1  Remove the rack of culture tubes from
      the incubator,  read and record gas
      production for each tube.

   2  Some tubes will be lauryl tryptose broth
      and some will be brilliant green lactose
      bile broth (BGLB). Be sure to record
      results from LTB under the 4 8-hour
      LTB column and the BGLB  results under
      the 24-hour column of the data sheet.

   3  Label tubes of BGLB to-correspond with
      all (if any) 48-hour gas-positive cultures
      in lauryl tryptose broth.  Transfer one
      loopful  of culture from each gas-positive
      LTB culture to the correspondingly-
      labeled tube of BGLB.   NOTE: All
      tubes of LTB culture which were
      negative at  24 hours and became
      positive at 48 hours are to be  transferred.
      The option described above for 24-hour
      cultures does not apply at 48 hours.

   4  If the Fecal Coliform Test is included
      in the testing procedure, consult
      Section V of the part of the  outline
      of testing procedures.

   5  Incubate the 24-hour gas-negative
      BGLB tubes and any newly-inoculated
      tubes of BGLB 24+2 hours at 35° +

   6  Discard all tubes of LTB and all 24-hour
      gas-positive BGLB cultures.

D  72-hour Procedures

   1  If any cultures remain to be examined,
      all will be BGLB.   Some may  be 24
       hours old and some may be 48 hours
       old.  Remove such cultures from the
       incubator, examine each tube for gas
       production, and record results on the
       data sheet.
    2  Be sure to record the results of 24-hour
       BGLB cultures in the  "24" column under
       BGLB and the 48-hour results under the
        48" column of the  data sheet.

    3  Return any 24-hour gas-negative cultures
       for incubation 24 + 2 hours at 35 +

    4  Discard aU gas-positive BGLB cultures
       and all 48-hour gas-negative cultures
       from BGLB.

    5  It is possible that all cultural work and
      results for the Confirmed  Test have
      been finished at this point. If so, codify
      results and determine  Confirmed Test
      coliforms per 100 ml as described in
      the outline on use of MPN  Tables.

E 96-hour Procedures

   At most only a few 48-hour cultures in
   BGLB may be present.   Read and record
   gas production of such cultures in the "48"
   column under BGLB on the data sheet.
   Codify  results and determine  Confirmed
   Test coliforms per 100 ml.

F  Streak-plate methods for the  Confirmed
   Test, using eosin methylene blue agar or
   Endo agar plates, are accepted procedures
   in Standard Methods. The worker who
   prefers to use one of these media in
   preference to BGLB (also  approved in
   Standard Methods) is advised  to refer to
   the current edition of "Standard Methods-
   for the  Examination of Water  and Waste-
   water"  for procedures.

       MPN Methods

 (Note that this description starts with the
 sample inoculation and proceeds through the
 Presumptive and the Confirmed Test stages.
 In addition, the Fecal  Coliform Test is
 referred to as an optional adjunct to the

 A First-Day Procedures

    1  Prepare a  laboratory data sheet for the
       sample.  Record the following information:
       assigned laboratory number, source of
       sample, date and time of collection,
       temperature of the source,  name of
       sample collector,  date and time of
       receipt of sample  in the  laboratory.
       Also  show  the date and time of starting
       tests in the laboratory, name(s) of
       worker(s) performing the laboratory
       tests, and  the sample volumes planted.

     2  Label the tubes  of lauryl tryptose broth
       required for the initial planting of the
       sample.  The label should bear three
       identifying marks. The upper number
       is the identification of the worker(s)
       performing the test (applicable to  •
       personnel in training courses),
       the number .immediately below is the
       assigned laboratory number,  corres-
       ponding with the laboratory record
       sheet.  The lower number is the code
       to designate the sample  volume and
       which tube of a  replicate series is
       indicated.   Guidance  on  labeling for
       laboratory data number  and identification
       of individual tubes is described else-
       where in this outline.
   NOTE: If 10-ml samples are being
   plated, it is necessary to use tubes
   containing the correct concentration
   of culture medium.  This has previously
   been noted elsewhere in this outline
   and referral is made to tables.

3  Place the labeled culture tubes in an
   orderly arrangement in a culture tube
   rack,  with the tubes intended for the
   largest sample volumes in the front
   row, and those intended for  smaller
   volumes in the succeeding rows.

4  Shake the sample vigorously, approxi-
   mately 25 times,  in an up-and-down

5  Measure the predetermined  sample
   volumes into the labeled tubes of lauryl
   tryptose broth,  using care to avoid
   introduction of any bacteria  into the
   culture medium except those in the

   a  Use a  10-ml pipet for  10  ml sample
     portions, and 1-ml pipets for portions
     of 1 ml or less.  Handle sterile
     pipets only near the mouthpiece,
     and protect the delivery end from
     external contamination.  Do not remove
     the cotton plug in the mouthpiece
     as this is intended to protect the
     user from ingesting any sample.
      When using the pipet to withdraw
      sample portions, do not dip the
      pipet more than 1/2 inch into the
      sample; otherwise sample running
      down the outside of the pipet will
      make measurements inaccurate.

      When delivering the sample into the
      culture medium,  deliver sample
      portions of 1 ml or less down into

                                                                      MPN Methods
         the culture tube near the surface of
         the medium.  Do not deliver small
         sample volumes at the top of the
         tube and allow them to run down
         inside the tube; too much of the
         sample will fail to reach the culture

      d  Prepare preliminary dilutions of
         samples for portions of 0. 01 ml or
         less before delivery into the culture
         medium.   See'Table 2 for preparation
         of dilutions.   NOTE: Always deliver
         diluted sample portions into  the
         culture medium as soon as possible
         after preparation.  The interval
         between preparation of dilution and
         introduction of sample into the
         medium never should be as much as
         30 minutes.

   6  After measuring all portions of the
      sample into their respective tubes of
      medium,  gently shake the rack  of
      inoculated tubes  to insure good  mixing
      of sample with the culture medium.
      Avoid vigorous shaking, as air  bubbles
      may be shaken into the fermentation
      vials and thereby invalidate the test.

   7  Place the rack of inoculated tubes in
      the incubator at 35O + 0. 50 C for 24 +
      2 hours.

B  24-hour Procedures

   1  Remove the rack of lauryl tryptose broth
      cultures from the incubator, and shake
      gently.  If gas is about to appear in the
      fermentation vials, the shaking will
      speed the process.

   2  Examine each tube carefully.  Record,
      in the column "24" under LST on the
      laboratory data sheet, each tube showing
      gas in the fermentation vial as a positive
      (+) test and each  tube not showing gas
      as a negative (-)  test.  GAS IN ANY

   3  Retain all gas-positive tubes of lauryl
      tryptose broth culture in their place in
      the rack,  and proceed.
   4  Select the gas-positive tubes of lauryl
      tryptose broth culture for the  Confirmed
      Test procedures.  Confirmed Test
      procedures jnav_not be required for
      all gas-positive cultures. If,  after
      24-hours of incubation,  all five
      replicate cultures are gas-positive for
      two  or more consecutive sample
      volumes, then select the set of five
      cultures representing the smallest
      volume of sample in which all tubes
      were gas-positive.  Apply Confirmed
      Test procedures to all these cultures
      and  to any other  gas-positive cultures
      representing smaller volumes of
      sample, in which some tubes were
      gas-positive and some were gas-

   5  Label one tube of brilliant green lactose
      bile broth (BGLB) to correspond with
      each tube of lauryl tryptose broth
      selected for Confirmed Test procedures.

   6  Gently shake the rack of Presumptive
      Test cultures. With a flame-sterilized
      inoculation loop transfer one loopful  of
      culture from each gas-positive tube to
      the corresponding tube of BGLB.  Place
      each newly inoculated culture into
      BGLB in the position of the original
      gas-positive tube.

   7  If the Fecal Coliform Test is included
      in the testing procedure, consult
      Section V of this  outline for details of
      the testing procedure.

   8  After making the transfer, the rack
      should contain some 24-hour gas-
      negative tubes of lauryl tryptose borth
      and the newly inoculated BGLB,
      Incubate the rack of cultures at 35° C
      + 0.5C-C for 24+2 hours.

C  48-hour Procedures

   1  Remove the rack of culture tubes from
      the incubator,  read and record gas
      production for each tube.

   2  Some tubes will be lauryl tryptose broth
      and  some will be brilliant green lactose

     MPN Methods
     bile broth (BGLB).  Be sure to record
     results from LTB under the 48- hour
     LTB column and the BGLB  results
     under the 2 4- hour column of the data

   3 Label tubes of BGLB to correspond with
     all (if any) 48-hour gas-positive cultures
     in lauryl tryptose broth.  Transfer one
     loopful of culture from each gas-positive
     LTB culture to the correspondingly-
     labeled tube of BGLB.  NOTE: All tubes
     of LTB culture which were  negative at
     24 hours and became positive at 48 hours
     are to be transferred.  The Option
     described above  for 24-hour LTB
     cultures does not apply at 48 hours.

   4 Incubate the 24-hour gas-negative BGLB
     tubes and any newly- inoculated tubes of
     BGLB 24 + 2 hours at 35° + 0. 5°C.
     Retain all 24- hour gas- positive cultures
     in BGLB for further test procedures.

   5 Label a Petri dish preparation of eosin
     methylene  blue agar (EMB agar)  to
     correspond with  each gas-positive
     culture in BGLB.

   6 Prepare a  streak plate for  colony
     isolation from each  gas-positive  culture
     in BGLB on the correspondingly- labeled
     EMB agar  plate.

     Incubate the EMB agar plates 24  + 2
     hours at 35° + 0.5<>C.

D  72-hour Procedures

   1 Remove the cultures from the incubator.
     Some may  be  on  BGLB; several EMB
          plates also  can be expected.
      Examine and record gas production
      results for any cultures in BGLB.

      Retain any gas-positive BGLB cultures
      and prepare streak plate inoculations
      for colony isolation in EMB agar.
      Incubate the EMB agar plates 24 +
      2 hours at 35 + 0.5° C.  Discard the
      gas- positive B~GLB cultures after
   4 Reincubate any gas-negative BGLB
     cultures 24 + 2 hours at 35° +  0. 5° C.

   5 Discard all 48-hour gas-negative BGLB

   6 Examine the EMB agar plates for the
     type of colonies developed thereon.
     Well-isolated colonies having a dark
     center (when viewed from the lower
     side, held toward a light) are termed
     "nucleated or fisheye" colonies,  and
     are regarded as "typical" coliform
     colonies.  A surface sheen  may or may
     not be present on  "typical"  colonies.
     Colonies which are pink or  opaque but
     are not nucleated are regarded as
     "atypical  colonies. "  Other colony
     types are considered "noncoliform. "
     Read and  record results as + for
     "typical"  (nucleated) colonies + for
     "atypical" (non-nucleated pink or
     opaque colonies),  and - for other types
     of colonies which might develop.

   7 With plates bearing "typical" colonies,
     select at least one well-isolated colony
     and transfer it to a correspondingly-
     labeled tube of lactose broth and to an
     agar slant.  As a  second choice, select
     at least two "atypical" colonies (if
     typical colonies are not present) and
     transfer them to labeled tubes  of
     lactose broth and to agar slants. As a
     third choice, in the absence of typical
     or atypical coliform-like colonies,
     select at least two well-isolated
     colonies representative of those
     appearing on the EMB plate, and trans-
     fer them to lactose broth and to agar

   8 Incubate all cultures transfered from
     EMB agar plates 24+2 hours  at 35 +

E  96-hour Procedures

   1 Subcultures from the samples being
     studied may include:  48-hour tubes
     of BGLB, EMB agar plates, lactose
     broth tubes,  and agar slant cultures.

                                                                 MPN Methods
If any 48-hour tubes of BGLB are
present,  read and record gas production
in the "48" column under BGLB.  From
any gas-positive BGLB cultures pre-
pare streak plate inoculations for colony
isolation on EMB agar.   Discard all
tubes of BGLB, and  incubate EMB agar
plates 24 + 2 hours at 35 + 0. 5° C.

If any EMB plates are present, examine
and record results in the "EMB" column
of the data sheet.  Make  transfers to
agar slants and to lactose broth from
all EMB agar plate cultures.  In
decreasing order of  preference, transfer
at least one typical colony,  or at least
two atypical colonies, or at least two
colonies representative of those on the

Examine and record results from the
lactose broth cultures.

Prepare a Gram-stained smear from
each of the agar slant cultures,  as

NOTE:  Always prepare Gram stain
from an actively growing culture,
preferably about 18 hours old, and
never more than 24 hours old.  Failure
to observe this precaution often results
in irregular staining reactions.

a  Thoroughly clean a glass slide to
   free it of any trace of oily film.

b  Place one drop of distilled water on
   the slide.

c  Use the inoculation needle to suspend
   a tiny amount of growth from the
   nutrient agar slant culture in the
   drop of water.

d  Mix the thin suspension of cells  with
   the tip of the inoculation needle, and
   allow the water to evaporate.

e  "Fix" the smear by gently warming
   the slide over a flame.

f  Stain the smear by flooding it for 1
   minute with crystal violet solution.
g  Flush the excess crystal violet
   solution off in gently running water,
   and gently blot dry with filter
   paper or with other clean absorbent

h  Flood the smear with Lugol's
   iodine for 1 minute.

i  Wash the  slide in gently running
   water and blot dry with filter paper.

j  Decolorize the smear with 95%
   alcohol solution with gentle
   agitation for 10-30 seconds,
   depending upon extent of removal
   of crystal violet dye,  then blot dry.

k  Counterstain for 10 seconds with
   safranin  solution,  then wash in
   running water and blot dry.

1  Examine the  slide under the
   microscope,  using the oil
   immersion lens. Goliform
   bacteria  are  Gram-negative,
   nonspore-forming, rod-shaped
   cells, occurring singly,  in pairs,
   or rarely in short chains.

m If typical  coliform staining reaction
   and morphology are observed,
   record + in the appropriate space
   under the "Gram Stain" column of
   the data sheet.  If typical morphology
   and staining reaction are not
   observed, then mark it + or -,  and
   make suitable comment in the
   "remarks" column at the right-hand
   side of the data sheet.

n  If spore-forming bacteria are
   observed, it will be necessary to
   repurify the culture from which
   the observations were made.
   Consult the instructor, or refer
   to Standard Methods,  for procedures.

At this point,  it is possible that all
cultural work for the Completed Test
has been finished.  If so,  codify results
and determine Completed Test coliforms
per  100 ml.

       MPN Methods
 F  120-hour Procedures and following:

    1  Any procedures to be undertaken from
      this point are "straggler" cultures on
      media already described, and requiring
      step-by-step methodology already given
      in detail.   Such  cultures may be on:
      EMB plates, agar slan4e, or lactose
      broth.  The same time-and-temperature
      of incubation required for earlier studies
      applies to the "stragglers" as do the
      observations, staining reactions,  and
      interpretation of results. On con-
      clusion of all cultural procedures,
      codify results and determine Completed
      Test coliforms per 100 ml.

A General Information

   1  The procedure described is an elevated
      temperature test for fecal  coliform

   2  Equipment required for the tests are
      those required for the Presumptive
      Test of Standard Methods,  a water-bath
      incubator,  and the appropriate culture

B Fecal Coliform Test with EC  Broth

   1  Sample:  The test is applied to gas-
      positive tubes from the Standard
      Methods Presumptive Test (lauryl
      tryptose broth), in parallel with
      Confirmed Test procedures.

   2  24-hour Operations.  Initial procedures
      are the planting procedures described
      for the Standard Methods Presumptive
      Coliform test.

      a After reading and recording gas-
        production on lauryl tryptose broth,
        temporarily retain all gas-positive

      b  Label a tube of EC broth to corre-
         spond with each gas-positive tube
        of lauryl tryptose broth. The option
        regarding transfer of only a limited
      number of tubes to the Confirmed
      Test sometimes can be applied here.
      However, the worker  is urged to
      avoid exercise of this option until
      he has  assured the applicability of
      the option by preliminary testfe on
      the sample source.
   c  Transfer one loopful of culture from
      each gas-positive culture in lauryl
      tryptose broth to the correspondingly
      labeled tube of EC broth.

   d  Incubate EC broth tubes 24 i 2 hours
      at 44. 5 + 0. 2°C in a waterbath
      with water depth sufficient to come
      up at least as high as the top of the
      culture medium in the tubes. Place
      in waterbath as soon as possible
      after inoculation and always within
      30 minutes  after inoculation.

3  48-hour operations

   a  Remove the rack of EC cultures
      from the waterbath, shake gently,
      and record  gas production for each
      tube.  Gas in any quantity is a
      positive test.

   b  As soon as  results are recorded,
      discard all  tubes.  (This is a 24-
      hour test  for EC broth inoculations
      and not a  48-hour test.)

   c  Transfer  any additional 48-hour
      gas-positive tubes of lauryl tryptose
      broth to correspondingly labeled
      tubes of EC broth.   Incubate 24 +
      2 hours at 44. 5 + 0. 2°C.

4  72-hour operations

   a  Read and  record gas production for
      each tube.  Discard all cultures.

   b  Codify results and determine fecal
      coliform count per 100 ml of sample.

                                                                                          MPN Methods
                                         TESTS FOR COUFOKM GROUP

(24 HR.+ 2 HR.J
                                         CAS NEGATIVE
                                          LACTOSE A LAURYL TtYPTOSE
                                          MOTH ARC INTERCHANGEABLE MEDIA
                                          AMD ARE MCUBATCD AT 35 DEC C+
                                          OS DEC C.

                                          GAS POSmVK TUBES (ANY AMOUNT
                                          OF GAS; CONSTITUTE A POSITIVE
                                          PRESUMPTIVE TEST

                                          TOTAL INCUBATION TIME FOR LACTOSE
                                          OR ITB IS 48 HRS.± 3 HRS.
                                GAS POSITIVE
                                                        GAS NEGATIVE
                                                    COUFORM GROUP ABSENT
                     CONFIRMATORY BROTH
                  BRIU1ANT GREEN LACTOSE BKf
                EJMB PLATES
                tNDO AGAR
  ALTERNATE  /   \
,  CONRRMH)  I  _ \  j
                              GAS POSITIVE
                                              GAS NEGATIVE




                                                       INCUBATE BG18 TUBES FOR 48 HRS.
                                                      1 3 HRS. AT 35 DEC. C ± OS DEC. C.
                                          INCUBATE EMB OR ENDOAGAR
                                          PLA TES FOR 24 HRS. ± 2 HRS A T
            GRAJM + AND     GRAM NEGATIVE
            RODS AND/Ot        RODS
             FOAM ATE
                      GAS POSITIVE
                                       GAS NEGATIVE

                                       COUFORM GROUP ABSENT
            GAS POSITIVE
                                 GAS NEGATIVE

                                 COUFORM GROUP ABSENT

                                           Part 3
                                  (Day-By-Day Procedures)

 A  The same sampling and holding procedures
    apply as for the coliform test.

 B  The number of fecal streptococci in water
    generally is lower than the number of
    coliform bacteria. It is good practice
    in multiple  dilution tube tests to start the
    sample planting series with one sample
    increment larger  than for the coliform
    test. For example: If a  sample planting
    series of 1.0,  0.1, 0.01, and 0.001 ml
    is planned for the coliform test,  it is
    suggested that a series of 10, 1. 0, 0. 1,
    and 0. 01 ml be planted for the fecal
    streptococcus test.

 C  Equipment required for the test is the same
    as  required for the Standard Methods
    Presumptive and Confirmed  Tests, except
    for the differences in culture media.

 A First-Day Operations

   1  Prepare the sample data sheet and
      labeled tubes of azide dextrose broth
      in the same manner as for the
      Presumptive Test.  NOTE: If 10-ml
      samples are included in the series,  be
      sure to use a special concentration
      (ordinarily double-strength) of azide
      dextrose broth for these  sample

   2  Shake the  sample vigorously, approxi-
      mately 25 times,  in an up-and-down

   3  Measure the predetermined sample
      volumes into the labeled  tubes of azide
      dextrose broth,  using the sample
      measurement and delivery techniques
      used for the Presumptive Test.
   4  Shake the rack of tubes of inoculated
      culture media, to insure good mixing
      of sample with medium.

   5  Place the rack of inoculated tubes in
      the incubator at 35° + 0. 5° C for 24 +
      2 hours.

B  2 4-hour Operations

   1  Remove the rack of tubes from the
      incubator.   Read and record the results
      from each tube.  Growth is a positive
      test with this test.  Evidence of growth
      consists either of turbidity  of the
      medium, a "button" of sediment at the
      bottom  of the culture tube,  or both.

   2  Label a tube of ethyl violet  azide broth
      to correspond with each positive  culture
      of azide dextrose broth.  It may be
      permissible to use the same confirmatory
      option as described for the  coliform
      Confirmed Test, in this outline.

   3  Shake the rack of cultures gently, to
      resuspend any living  cells which have
      settled  out to the bottom of  the culture

   4  Transfer three loopfuls of culture from
      each growth-positive tube of azide
      dextrose broth to the correspondingly
      labeled tube of ethyl violet azide broth.

   5  As transfers are made, place the newly
      inoculated tubes of ethyl violet azide
      broth in the positions in the rack
      formerly occupied by the growth-
      positive tubes of azide dextrose broth.
      Discard the tubes of azide dextrose
      broth culture.

   6  Return  the  rack,  containing 24-hour
      growth-negative azide dextrose broth
      tubes and newly-inoculated tubes of
      ethyl violet azide broth, to the incubator.
      Incubate 24 + 2 hours at 35° + 0, 5OC.

 MPN Methods
C  48-hour Operations

   1  Remove the rack of tubes from the
      incubator.  Read and report results.
      Growth, either in azide dextrose broth
      or in ethyl violet azide broth,  is a
      positive test.  Be sure to report the
      results of the azide dextrose broth
      medium under the  "48" column for that
      medium and the results of the  ethyl
      violet azide broth cultures under the
      "24" column for that medium.

   2  Any 48-hour growth-positive cultures
      of azide dextrose broth are to  be
      transferred (three loopfulls) to ethyl
      violet azide broth.  Discard all 48-hour
      growth-negative tubes of azide dextrose
      broth and all 24-hour growth-positive
      tubes of ethyl violet azide broth.

   3  Incubate the 24-hour growth-negative
      and  the newly-inoculated tubes of ethyl
      violet azide broth 24 +  2 hours at 35O
      + 0.5QC.

D  72-hour Operations

   1  Read and report growth results of all
      tubes of ethyl violet azide broth.

   2  Discard all growth-positive  cultures
      and  all 48-hour growth-negative
      Codify results and determine fecal
      streptococci per 100 ml.

1  Standard Methods for the Examination of
      Water and Wastewater (13th Ed).
      Prepared and published jointly by
      American Public Health Association,
      American Water Works Association,
      and Water Pollution Control
      Federation.   1971.

2  Geldreich,  E.E.,  Clark, H.F.,  Kabler.
      P.W.,  Huff, C.B. and Bordner,  R. H.
      The Coliform Group.  II.  Reactions
      in EC Medium at 45° C.   Appl.
      Microbiol.  8:347-348.   1958.

3  Geldreich,  E. E.,  Bordner,  R.H..  Huff,
      C.B., Clark. H. F. and Kabler, P.W.
      Type Distribution of Coliform Bacteria
      in the Feces of Warm-Blooded Animals.
      J. Water Pollution Control Federation.
      34:295-301.   1962.

4  Recommend Proc. for the Bacteriological
      Examination of Sea Water and Shellfish.
      3rd Edition,  American Public Health
      Association.   1962.
   3  Reincubate any 24-hour growth-negative
      cultures in ethyl violet azide broth 24
      + 2 hours at  35O  +  0.5OC.

E  96-hour Operations

   1  Read and report  growth results of any
      remaining tubes  of ethyl violet azide
This outline was prepared by H. L. Jeter,
Director,  National Training Center,
Office of Water Programs, Environmental
Protection Agency,  Cincinnati, OH 45268.


A Introduction

   Successful application of membrane filter
   methods requires development of good
   routine operational practices.  The
   detailed basic procedures described in
   this Section are applicable to all mem-
   brane filter methods in water bacteriology
   for filtration, incubation, colony counting,
   and reporting of results.  In addition,
   equipment and supplies used in all  mem-
   brane filter procedures are described here
   and not repeated elsewhere in such detail.

   Workers using membrane filter methods
   for the first time are urged to become
   thoroughly familiar with these basic
   procedures and precautions.

B General Supplies and Equipment List

   Table 1 is a check list of materials.

C "Sterilizing" Media

   Set tubes  in a boiling waterbath for 10
   minutes.  This method suffices for
   medium in tubes up to 25 X 150 mm.
   Frequent  agitation improves dissolving
   of the medium.

   Alternately,  coliform media can be
   directly heated on a hotplate to the  first
   bubble of boiling.  Stir the medium
   frequently if direct heat is used, to avoid
   charring the  medium.

   Do not autoclave.
D  General Laboratory Procedures with
   Membrane Filters

   1  Prepare data sheet

      Minimum data required are:  sample
      identification,  test performed including
      media and methods, sample filtration
      volumes, and the bench numbers
      assigned to individual membrane filters.

   2  Disinfect the laboratory bench surface.

      Use a suitable disinfectant solution and
      allow the surface to dry before

   3  Set out sterile culture containers  in an
      orderly arrangement.

   4  Label the culture containers.

      Numbers correspond with the filter
      numbers shown on the data  sheet.

   5  Place  one sterile absorbent pad* in
      each culture container, unless an  agar
      medium is being used.

      Use sterile forceps for all manipulations
      of absorbent pads and membrane filters.
      Forceps  sterility is maintained by
      storing the working tips in about 1 inch
      of methanol or ethanol. Because the
      alcohol deteriorates the filter, dissipate
      it by burning before using the forceps.
      Avoid  heating the forceps in the burner
      as hot metal chars the filter.
*When an agar medium is used, absorbent pads are not used.  The amount of medium should be
sufficient to make a layer approximately 1/8" deep in the culture container.  In the 50 mm
plastic culture containers this corresponds to approximately 6-8 ml of culture medium.

NOTE: Mention of commercial products and manufacturers does not imply endorsement by the
        Office of Water Programs,  Environmental Protection Agency.
 W.BA.mem. 8H.11.71

Membrane Filter Laboratory and Field Procedures
                         Table 1.  EQUIPMENT, SUPPLIES AND MEDIA (Cont'd)

Half-round glass paper weights for
colony counting, with lower half of a
2-oz metal ointment box
Hand tally, single unit acceptable.
hand or desk type
Stereoscopic (dissection) microscope.
magnification of 10X or 15X, prefer-
able binocular wide field type
Bacteriological inoculating needle
Wire racks for culture tubes,
10 openings by five openings pre-
ferred, dimensions overall approxi-
mately 6" X12"
Phenol Red Lactose Broth in 16 X
150 mm fermentation tubes with
metal caps, 10 ml per tube
Eosin Methylene Blue Agar
(Lcvine) in petri plates, prepared
ready for use
Nutrient agar slants, in screw
capped tubes, 16 X126 mm
Gram stain solutions, 4 solutions
per complete set
Microscope, compound, binocular,
with oil immersion lens, micro-
scope lamp and immersion oil
Microscope slides, new, clean.
1" X3" size
Water proof plastic bags
for fecal coliform culture
dish incubation
M-Endo medium, MF dehydrated
medium in 25 X 95 mm flat bottomed
screw- capped glass vials, 1.44 g
per tube, sufficient for 30 ml of
Ethanol, 95% in small bottles or
screw- capped tubes, about 20 ml
per tube
Sodium benzoate solution, 12%
aqueous, in 25 XI 50 mm screw-
capped tubes, about 10 ml per tube
L. E.S. EndoAgarMF. dehydrated
M-Endo medium, 0. 36 g per 25 X
95 mm flat bottomed screw- capped
glass vial, plus 0.45 g agar, for 30 ml
Lactose Lauryl Sulfate Tryptose Broth
in 25 X 150 mm test tube without
included gas tube, about 25 ml, for
enrichment in L. E. S. method
Standard Tests
M - Endo





L. E. S.






Nonstandard Tests






















             Membrane Filter Laboratory and Field Procedures

Funnel unit assemblies
Ring stand, with about a 3" split ring, to
support the filtration funnel
Forceps, curved-end round tipped,
special type for MF work
Methanol, in small wide-mouthed bottles,
about 20 ml for sterilizing forceps
Suction flasks, glass, 1 liter, mouth to
fit No. 8 stopper
Rubber tubing, 2-3 feet, to connect
suction flask to vacuum services, latex
rubber 3/16" I.D. by 3/32" wall
Pinch clamps strong enough for tight
compression of rubber tubing above
Pipettes, 10 ml, graduated, Mohr type,
sterile, dispense 10 per can per working
space per day. (Resterilize daily to
meet need).
Pipettes, 1 ml, graduated, Mohr type.
sterile, dispense 24 per can per working
space per day. (Resterilize daily to
meet need).
Pipette boxes, sterile, for 1 ml and
10 ml pipettes (sterilize above pipettes
in these boxes).
Cylinders, 100 ml graduated, sterile.
(resterilize daily to meet need),
Jars, to receive used pipettes
Gas burner, Bunsen or similar
laboratory type
Wax pencils, red, suitable for writing
on glass
Sponge in dilute iodine, to wipe down the
desk tops
Membrane filters (white, grid marked.
sterile, and suitable pore size for
microbiological analysis of water)
Absorbent pads for nutrient, (47 mm in
diameter), sterile, in units of 10 pads
per package. Not required if medium
contains agar.
Petri dishes, disposable, plastic.
50 X 12 mm, sterile
Waterbath incubator 44.5 + 0.2°C
Vegetable crispers, or cake boxes.
plastic, with tight fitting covers, for
membrane filter incubations
Fluorescent lamp, with extension cord
equipped with a simple lens of about
4X magnification
Ring stand, with clamps, utility type
Standard Tests


















L. E.S.


















Nonstandard Tests

























































Membrane Filter Laboratory and Field Procedures
                          Table 1.  EQUIPMENT, SUPPLIES AND MEDIA (Cont'd)
                                      Standard Tests
M-FC Broth for fecal coliform.
dehydrated medium in 25 X95 mm
flat bottomed screw-capped glass
vials, 1. 23 g per tube, sufficient
for 30 ml of culture medium
Rosolic acid, 1% solution, in
0. 2N NaOH, in 25 X 150 mm flat
bottomed screw- capped tubes.
about 5 ml per tube, freshly
M-Enterococcus Agar, dehydrated
medium in 25 X150 mm screw-
capped tubes, sufficient for 30 ml.
1. 26 g per tube
Dilution bottles, 6-oz, preferable
boro- silicate glass, with screw-
cap (or rubber stopper protected
by paper) , each containing 99 ml
of sterile phosphate buffered
distilled water
Electric hot plate surface
Beakers, 400 - 600 ml (for water-
bath in preparation of membrane
filter culture media)
Crucible tongs, to be used at
electric hot plates, for removal
of hot tubes of culture media for
boiling waterbath




L. E.S.



















                                                                 Nonstandard Tests

                                  Membrane Filter Laboratory and Field Procedures
     Deliver enough culture medium to
     saturate each absorbent pad, * using
     a sterile pipette.

     Exact quantities cannot be stated
     because pads and  culture containers vary.
     Sufficient medium should be applied so
     that when the culture container is tipped,
     ajfood-sized drop of culture medium.
     freely drains out of the absorbent pad.

     Organize supplies and equipment for
     convenient sample filtration.  In
     training courses,  laboratory instructors
     will suggest useful arrangements;
     eventually the individual will select a
     system of bench-top organization most
     suited to his own needs.  The important
     point in any arrangement is to have all
     needed equipment and supplies con-
     veniently at hand, in such a pattern as
     to minimize lost time in useless motions.

     Lay a sterile membrane filter on the
     filter holder, grid-side  up,  centered
     over the porous part of the filter
     support plate.

     Membrane filters are extremely
     delicate and easily damaged.  For
     manipulation,  the sterile forceps
     should always  grasp the outer part
     of the filter disk,  outside the part
     of the filter through which the  sample

     Attach the funnel element to the base
     of the filtration unit.

     To avoid damage to the membrane
     filter, locking forces should only be
     applied at the  locking arrangement.
     The funnel element never should be
     turned or twisted  while being seated
     and locked to the lower element of the
     filter holding unit.  Filter holding units
     featuring a bayonet joint and locking
     ring to join the upper element to the
     lower element require special care on
     the part of the operator.  The locking
     ring should be turned sufficiently to
     give a snug fit, but should not be
     tightened excessively.
                                           10  Shake the sample thoroughly.

                                           11  Measure sample into the funnel with
                                               vacuum turned off.
                                              The primary objectives here are:
                                              1) accurate measurement of sample;
                                              and  2) optimum distribution of colonies
                                              on the filter after incubation.  To
                                              meet these objectives, methods of
                                              measurement and dispensation to the
                                              filtration assembly are varied with
                                              different sample filtration volumes.

                                              a  With  samples greater than 20 ml,
                                                 measure the sample with a sterile
                                                 graduated cylinder and pour it into
                                                 the funnel.  It is important to rinse
                                                 this graduate with sterile buffered
                                                 distilled water to preclude the loss
                                                 of excessive sample volume.  This
                                                 should be poured into the funnel.

                                              b  With  samples of  10 ml to 20 ml,
                                                 measure the sample with a sterile
                                                 10 ml or 20 ml pipette, and pipette
                                                 on a dry membrane in the filtration

                                              c  With  samples of 2 ml to 10 ml,  pour
                                                 about 20 ml of sterile dilution water
                                                 into the filtration assembly,  then
                                                 measure the sample into  the sterile
                                                 buffered dilution water with a 10 ml
                                                 sterile pipette.

                                              d  With  samples of 0. 5 to 2  ml, pour
                                                 about 20 ml of sterile dilution water
                                                 into the funnel assembly, then
                                                 measure the sample into  the sterile
                                                 dilution water in the funnel with a
                                                 1 ml or a  2  ml pipette.

                                              e  If a sample  of less than 0. 5 ml is to
                                                 be filtered,  prepare appropriate
                                                 dilutions in  sterile dilution water,
                                                 and proceed as applicable in item c
                                                 or d above.

                                                 When dilutions of samples are needed,
                                                 always make the  filtrations as soon
                                                 as possible  after dilution of the
                                                 sample; this never should exceed
Mention of commercial products and manufacturers does not imply endorsement
by the Office of Water Programs, Environmental Protection Agency.

   Membrane Filter Laboratory and Field Procedures
       30 minutes.  Always shake sample
       dilutions thoroughly before delivering
       measured volumes.

12  Turn on the vacuum.

    Open the appropriate spring clamp or
    valve, and filter the sample.

    After sample filtration a few droplets
    of sample usually remain adhered to
    the funnel walls.  Unless these droplets
    are removed, the bacteria  contained in
    them will be a source of contamination
    of later samples.   (In laboratory
    practice the funnel unit is not routinely
    sterilized between successive filtrations
    of a series).  The purpose  of the funnel
    rinse is to flush all droplets of a sample
    from the funnel walls to the membrane
    filter.  Extensive tests have shown that
    with proper rinsing technique, bacterial
    retention on the funnel walls is negligible.

13  Rinse the sample through the filter.

    After all the sample has passed through
    the membrane filter, rinse down the
    sides of the funnel walls with at least
    20 ml of sterile dilution water.  Repeat
    the rinse twice after all the first rinse
    has passed through the filter.   Cut off
    suction on the filtration assembly.

14  Remove the funnel element of the filter
    holding unit.

    If a ring stand with split ring is used,
    hang the funnel element on  the ring;
    otherwise,  place the inverted funnel
    element on the inner surface  of the
    wrapping material.  This requires
    care  in opening the  sterilized package,
    but it is effective as a protection of the
    funnel ring from contamination.
15  Take the membrane filter from the
    filter holder and carefully place it,
    grid-side up on the medium.

    Check that no air bubbles have been
    trapped between the membrane filter
    and the underlying absorbent pad or
    agar. Relay the membrane if necessary.
Place in incubator after finishing
filtration series.
Invert the containers.  The immediate
atmosphere of the incubating membrane
filter must be at or very near 100%
relative humidity.

Count colonies which have  appeared
after incubating for the prescribed

A stereoscopic microscope magnifying
10-15 times and careful illumination
give best counts.

For  reporting results, the computation

   bacteria/100 ml =

   No. colonies counted X 100
   Sample volume filtered  in ml


   A total of 36 colonies grew after
   filtering a 10 ml sample.  The
   number reported is:
       36 colonies
          10 ml
               X 100 = 360 per 100 ml

                                    Membrane Filter Laboratory and Field Procedures

 A Standard Coliform Test (Based on M-Endo
   Broth MF)

   1   Culture medium

      a  M-Endo Broth MF Difco 0749-02
         or the equivalent BBL M-Coliform
         Broth 01-494

         Preparation of Culture Medium
         (M-Endo Broth)  for Standard MF
         Coliform Test
   Yeast extract                   1. 5
   Casitone or equivalent           5. 0
   Thiopeptone or equivalent        5. 0
   Tryptose                       10.0
   Lactose                        12.5
   Sodium desoxycholate            0.1
   Dipotassium phosphate           4.375 g
   Monopotassium phosphate        1.375 g
   Sodium chloride                 5.0   g
   Sodium lauryl sulfate            0.05
   Basic fuchsin (bacteriological)   1. 05
   Sodium sulfite                   2.1

   Distilled water (containing       1000 ml
   20.0 ml ethanol)
         This medium is available in
         dehydrated form and it is rec-
         ommended that the commercially
         available medium be used in
         preference to compounding  the
         medium of its individual constituents.

         To prepare the medium for use,
         suspend the dehydrated medium at
         the rate of 48 grams per liter of
         water containing ethyl alcohol at
         the rate of 20 ml per liter.

         As a time-saving convenience, it is
         recommended that the laboratory
         worker preweigh the dehydrated
         medium in closed tubes for several
         days,  or even weeks, at one operation.
                 With this system,  a large number
                 of increments of dehydrated medium
                 (e.g.,  1.44 grams), sufficient for
                 some convenient (e.g., 30 ml)
                 volume of finished culture  medium
                 are weighed and dispensed into
                 screw-capped culture tubes,  and
                 stored until needed. Storage should
                 preferably be in a darkened desiccator.
     A supply of distilled water containing
     20 ml stock ethanol per liter is

     When the medium is to be used, it
     is reconstituted by adding 30 ml of
     the distilled water-ethanol mixture
     per tube of pre-weighed dehydrated
     culture medium.

   b Medium is "sterilized" as directed
     in I, C.

   c Finished medium can be retained
     up to 96 hours if kept in a cool,
     dark place.  Many workers prefer
     to reconstitute fresh medium daily.

2  Filtration and incubation procedures
   are  as given in I, D.

   Special instructions:

   a For counting, use the wide field
     binocular dissecting microscope,  or
     simple lens.  For illumination, use
     a light source perpendicular to the
     plane of the membrane filter.  A
     small fluorescent lamp is ideal for
     the purpose.
                  Coliform colonies have a "metallic"
                  surface sheen under reflected light
                  which may cover the entire colony, or
                  it may appear only in the center.  Non-
                  coliform colonies range from
                  colorless to pink, but do not have
                  the characteristic sheen.

                  Record the colony counts  on the
                  data sheet, and compute the coliform
                  count per 100 ml of sample.

    Membrane Filter Laboratory and Field Procedures
   Standard Coliform Tests (Based on L. E. S.
   Endo Agar)

   The distinction of the L. E.S. count is a
   two hour enrichment incubation on LST
   broth.  M-Endo L. E.S. medium is used
   as agar rather than the broth.

   1  Preparation of culture medium
      (L. E.S. Endo Agar) for L. E.S.
      coliform test

      a Formula from McCarthy, Delaney,
        and Grasso f)
Bacto-Yeast Extract
Bacto- Thiopeptone
Dipotassium phosphate
Monopotassium phosphate
Sodium  chloride
Sodium  desoxycholate
Sodium  lauryl sulfate
Sodium  sulfite
Bacto-Basic fuchsin

Distilled water (containing
20 ml ethyl alcohol)
 0.05 g
 1.6  g
 0.8  g
15    g

1000 ml
      b  To rehydrate the medium, suspend
        51 grams in the water-ethyl alcohol

      c  Medium is "sterilized" as directed
        in I, C.

      d  Pour 4-6 ml of freshly prepared Agar
        into the smaller half of the container.
        Allow the  medium to cool and solidify.

   2  Procedures for filtration and incubation

      a  Lay out the culture dishes in a row
        or series of rows as usual. Place
        these with the upper (lid) or top
        side down.

      b  Place one  sterile absorbent pad in
        the larger half of each container
        (lid).  Use sterile forceps for all
        manipulations of the pads.
        (Agar occupies smaller half  or

      c  Using a sterile pipette, deliver
        enough single strength lauryl
        sulfate tryptose broth to saturate
        the pad only.  Excess interferes.

      d  Follow general procedures for
        filtering in I,  D. Place filters on
        pad with lauryl sulfate tryptose

      e  Upon completion of the  filtrations,
        invert the culture containers and
        incubate at 35° C for 1  1/2 to 2

   3  2-hour procedures

      a  Transfer the membrane filter from
        the enrichment pad in the upper half
        to the agar medium in the lower
        half of the container.   Carefully
        roll the membrane onto the agar
        surface to avoid trapping air
        bubbles beneath the membrane.

      b  Removal of the used absorbent pad
        is optional.

      c  The container is inverted and
        incubated 22 hours + 2  hours + 0. 5°C.

   4  Counting procedures are as in I, D.

   5  L. E.S. Endo Agar may be used as a
      single-stage medium (no enrichment
      step) in the same manner as M-Endo
      Broth, MF.

C  Delayed Incubation Coliform Test

   This technique is applicable in situations
   where there is an excessive  delay between
   sample collection and plating. The procedure
   is unnecessary when the interval be-
   tween sample collection and plating is
   within acceptable limits.
                      Preparation of culture media for
                      delayed incubation coliform test

                      a  Preservative media M-Endo Broth

                               Membrane Filter Laboratory and Field Procedures
     To 30 ml of M-Endo Broth MF
     prepared in accordance with
     directions in II, A, 1 of this
     outline,  add 1. 0 ml of a sterile
      12% aqueous solution of sodium

     L. E. S. MF Holding Medium -
     Coliform:  Dissolve 12.7 grams in
      1  liter of distilled water.  No
     heating is necessary.   Final pH
      7.1 + 0.1. This medium contains
      sodium benzoate.

   b Growth media

     M-Endo Broth MF  is used, prepared
     as described in II,  A,  1 earlier in
     this outline. Alternately,  L. E. S.
     Endo Medium may  be used.

2  General filtration followed is in I, D.

   Special procedures are:

   a Transfer the membrane filter  from
     the filtration apparatus to a pad
     saturated with benzoated M-Endo

   b Close the culture dishes and hold
     in a container at ambient temperature.
     This may be mailed or transported
     to a central laboratory. The mailing
     or transporting tube should contain
     accurate transmittal data sheets which
     correspond to properly labeled dishes.

     Transportation time, in the case of
     mailed containers, should not  exceed
     three days to the time of reception
     by the testing laboratory.

   c On receipt in the central laboratory,
     unpack mailing carton, and lay out
     the culture  containers on the labora-
     tory bench.

   d  Remove the tops from the culture
      containers.  Using sterile forceps,
      remove each membrane and its
      absorbent pad to the other half of
      the  culture container.
      e With a sterile pipette or sterile
        absorbent pad, remove preservative
        medium from the culture container.

      f Place a  sterile absorbent pad in
        each culture container, and deliver
        enough freshly prepared M-Endo
        Broth to saturate each pad.

      g Using sterile forceps, transfer the
        membrane to the new absorbent pad
        containing M-Endo Broth.  Place
        the membrane  carefully to avoid
        entrapment of air between the
        membrane and the  underlying
        absorbent pad.  Discard the
        absorbent pad containing pre-
        servative medium.

      h After incubation of 20 + 2 hours
               I             <•
        at 35°C, count colonies as in the
        above section A,  2.

      i If L. E.S. Endo A gar is used, the
        steps beginning with (e) above are
        omitted; and the membrane filter is
        removed from the preservative
        medium and transferred to a fresh
        culture container with L. E. S.  Endo
        Agar, incubated, and colonies
        counted in the usual way.

D  Verified Membrane Filter Coliform Test

   This procedure applies to identification
   of  colonies growing on  Endo-type media
   used for determination of total coliform
   counts.  Isolates from these colonies are
   studied for gas production from lactose
   and typical coliform morphology.  In
   effect,  the procedure corresponds  with
   the Completed Test stage of the multiple
   fermentation tube test for coliforms.


          1  Select a membrane filter bearing
             several well-isolated coliform-type

          2  Using sterile technique, pick all
             colonies in a selected area with the
             inoculation needle, making transfers
             into tubes  of phenol red  lactose broth
             (or  lauryl sulfate tryptose lactose


    Membrane Filter Laboratory and Field Procedures
          broth).  Using an appropriate data
          sheet record the interpretation of
          each colony, using, for instance,
          "C" for colonies having the typical
          color and sheen of coliforms; "NC"
          for colonies not conforming to
          coliform colony appearance on
          Endotype media.

 3  Incubate the broth tubes at 35O C+ 0. 5°C.

 4  At 24 hours:

   a  Read and record the results from
      the lactose broth fermentation tubes.
      The following code is suggested:

  O      No indication of acid or gas
         production,  either with or
         without evidence of growth.

  A      Evidence of acid but  not gas
         (applies only when a  pH indicator
         is included in the broth medium)
  G      Growth with production of gas.
         If pH indicator is used, use
         symbol AG to show evidence of
         acid.  Gas in any quantity is a
         positive test.

   b  Tubes not showing gas production are
      returned to the 35° C incubator.

   c  Gas-positive tubes are transferred
      as follows:

      1) Prepare a streak inoculation  on
         EMB agar for colony isolation, and
         using  the same  culture.

       2)  Inoculate a nutrient agar slant.

      3)  Incubate the EMB agar plates and
          slants at 35° C  + o. 5°C.
  5 At 48 hours:

    a  Read and record results of lactose
       broth tubes which were negative at
       24 hours and were returned for
       further incubation.
     b  Gas-positive cultures are subjected
        to further transfers as in 4c.
        Gas-negative cultures are discarded
        without further study; they are
        coliform- negative.

     c  Examine the cultures transferred
        to EMB  agar plates and to nutrient
        agar slants, as follows:

        1) Examine the EMB agar plate for
          evidence of purity of culture;  if
          the culture  represents more than
          one colony type,  discard the
          nutrient agar culture and reisolate
          each  of the  representative colonial
          types on the EMB plate and resume
          as with 4c for each isolation.
          If purity of culture appears evident,
          continue with c (2) below.

        2) Prepare a smear and  Gram stain
          from each nutrient agar slant
          culture.  The Gram stain should
          be made on a culture not more
          than 24 hours old.  Examine under
          oil immersion for typical coliform
          morphology, and record results.

  6  At 72 hours:

     Perform procedures described in 5c
     above,  and record results.

  7  Coliform colonies are  considered
     verified if the procedures demonstrate
     a pure  culture of bacteria which are
     gram negative nonspore-forming rods
     and produce gas from lactose at 35° C
     within  48 hours.
E  Fecal Coliform Count (Based on M-FC
   Broth Base)

   The count depends upon growth on a
   special medium at 44. 5 i- 0. 2°C.

   1 Preparation of Culture Medium
     (M-FC Broth Base) for Fecal
     Coliform Count

                                   Membrane Filter Laboratory and Field Procedures
      a  Composition

      Tryptose                      10. 0 g
      Proteose Peptone No. 3         5. 0 g
      Yeast extract                   3. 0 g
      Sodium chloride                5. 0 g
      Lactose                       12.5 g
      Bile  salts No.  3                1.5 g
      Rosolic acid* (Allied           10. 0 ml
      Aniline blue (Allied Chemical)   0. 1 g
      Distilled water
1000 ml
      b  To prepare the medium dissolve
         37.1 grams in a liter of distilled
         water which contains 10 ml of 1%
         rosolic acid (prepared  in 0.2 N

         Fresh solutions of rosolic acid give
         best results.  Discard  solutions
         which have changed from dark red
         to orange.

      c  To sterilize,  heat to boiling as
         directed in I, C.

      d  Prepared medium may be retained
         up to 4 days in the dark at 2-8° C.

   2  Special supplies

      Small water proof plastic  sacks capable
      of being sealed against water with
      capacity of 3 to 6 culture  containers.

    3   Filtration procedures are as given in
       I. D.

    4   Elevated temperature incubation

       a Place fecal coliform count mem-
         branes at 44.5+0.2 C as rapidly
         as possible.
  :Filter membranes for fecal coliform
  counts consecutively and immediately
  place them in their culture containers.
  Insert as many as six culture containers
  all oriented in the same way (i.e.,  all
  grid sides facing the same direction)
  into the sacks and seal.  Tear off the
  perforated top, grasp the side wires,
  and twirl the sack to roll the open end
  inside the folds of sack.  Then submerge
  the sacks with culture containers in-
  verted beneath the surface of a 44. 5
  + 0. 2 C water bath.

   b Incubate for 22+2 hours.

5  Counting procedures

   Examine and count colonies as follows:

   a Use a wide field binocular dissecting
     microscope with 5  - 10X magnification.

   b Low angle lighting from the side is

   c Fecal coliform colonies are blue,
     generally 1-3 mm in diameter.

   d Record the  colony counts on the
     data sheet,  and report the fecal
     coliform count per 100 ml of  sample.
     (I, D,  17 illustrates method)
               A 48 hour incubation period on a choice of
               two different media, giving high selectivity
               for fecal streptococci, are the distinctive
               features of the tests.
"•Prepare 1% solution of rosolic acid in 0.2 N NaOH.  This dye is practicaUy insoluble in water.


    Membrane Filter Laboratory and Field Procedures
 Test for Members of Fecal Streptococcal
 (Tentative, Standard Methods) M-
 Enterococcus Agar Medium

 1  Preparation of the culture medium

    a  Formula (The Difco formula is shown
       but equivalent constituents from
       other sources are equally acceptable).
    Bacto tryptose             20. 0 g
    Bacto yeast extract          5. 0 g
    Bacto dextrose              2. 0 g
    Dipotassium phosphate       4. 0 g
    Sodium Azide                0.4 g
    Bacto agar                 10. 0 g
    2, 3, 5, Triphenyl          0.1 g
       tetrazolium chloride

    b  The  medium is prepared by
       rehydration at the rate of 42 grams
       per 1000 ml of distilled water. It
       is recommended that the medium in
       dehydrated form be preweighed and
       dispensed into culture containers
       (about 25 X  150 mm) in  quantities
       sufficient for preparation of 30 ml
       of culture medium (1. 26 g per tube).

    c  Follow I, C, for "sterilizing" medium
       and dispense while hot into culture
       containers.  Allow plates to harden
       before use.

  2  List of  apparatus, materials, as given
    in Table I.

  3  Procedure,  in general, as given  in I.

    Special instructions

     a  Incubate for 48 hours,  inverted,
        with 100% relative humidity,  after
        filtrations are completed.  If the
        entire incubator does not have
        saturated humidity, acceptable
        conditions can be secured by placing
        the  cultures in a tightly closed
        container with wet paper, towels,
        or other moist material.
        After incubation, remove the
        cultures from the incubator,  and
        count all colonies under wide field
        binocular dissecting microscope
        with magnification set at 10X or
        20X.  Fecal streptococcus colonies
        are 0. 5 - 2 mm in diameter, and
        flat to raised smooth, and vary
        from pale pink to dark red in color.

        Report enterococcus count per
        100 ml of sample.  This is con-
        veniently computed:

        No.  fecal streptococci per 100 ml =
No. fecal streptococcus colonies counted
     Sample filtration volume in ml
B  Test for Members of Fecal Streptococcal
   Group based on KF-Agar

   1  Preparation of the culture medium

      a Formula:  (The dehydrated formula
        of Bacto 0496 is shown, but
        equivalent constituents from other
        sources are acceptable).  Formula
        is in grams per liter of reconstituted
   Bacto proteose peptone #3      10. 0
   Bacto yeast extract            10.0
   Sodium chloride (reagent grade) 5. 0
   Sodium glycerphosphate        10.0
   Maltose (CP)                  20.0
   Lactose (CP)                    1.0
   Sodium azide (Eastman)          0.4
   Sodium carbonate                0.636 g
      (Na2CO3  reagent grade)
   Brom cresol purple              0. 015 g
      (water  soluble)
   Bacto agar                    20.0   g

      b  Reagent

         2, 3,  5-Triphenyl tetrazolium
         chloride reagent (TPTC)

         This reagent is prepared by making
         a 1% aqueous solution of the above
         chemical passing it through a Seitz
         filter  or membrane filter.  It can

                                Membrane Filter Laboratory and Field Procedures
     be kept in the refrigerator in a
     screw-capped tube until used.

   c  The dehydrated medium described
     above  is prepared for laboratory
     use as follows:

     Suspend 7. 64 grams of  the dehydrated
     medium in 100 ml of distilled water
     in a flask with an aluminum foil

     Place the flask in a boiling water-
     bath, melt the dehydrated medium,
     and leave in the boiling waterbath
     an addional 5 minutes.

     Cool the medium to 50°-60OC, add
     1. 0 ml of the TPTC reagent, and

     For membrane filter studies, pour
     5-8 ml in each  50 mm glass or
     plastic culture  dish or enough to
     make a layer approximately 1/8"
     thick.  Be sure to pour  plates before
     agar cools and  solidifies.

     For plate counts, pour as for standard
     agar plate counts.

     NOTE:  Plastic dishes  containing
     media may be stored in a dark,  cool
     place up to 30 days without change
     in productivity of the medium,  pro-
     vided that no dehydration occurs.
     Plastic dishes  may be incubated  in
     an ordinary air incubator.  Glass
     dishes must be incubated in an
     atmosphere with saturated humidity.

2  Apparatus, and materials  as given in
   Table 1.

3  General procedure is as given in I.
     Special instructions

    a  Incubate 48 hours, inverted with
       100% relative humidity after
      b  After incubation,  remove the
         cultures from the incubator,  and
         count colonies under wide field
         binocular dissecting microscope,
         with magnification set at 10X or
         20X.  Fecal streptococcus  colonies
         are pale pink to dark wine- color.
         In size they range from barely
         visible to approximately 2mm in
         diameter.   Colorless colonies are
         not counted.

      c  Report fecal streptococcus count
         per 100 ml of sample.   This is
         computed as follows:

      No.  fecal streptococci per 100 ml =
 No. fecal streptococcus colonies ..
  Sample filtration volume in ml
 C Verification of Streptococcus Colonies

   1  Verification of colony identification
      may be required in waters containing
      large numbers of Micrococcus orga-
      nisms.  This has been noted
      particularly with bathing waters, but
      the problem is by no means limited to
      such waters.

   2  A verification procedure is  described
      in "Standard Methods for the Examination
      of Water and Wastewater," 13th ed,
      (1971).  The worker should  use.
      this reference for the step-by-
      step procedure.


 A Culture Media

    1  The standard coliform media used with
       laboratory tests are used.

    2  To simplify field operations, it is
       suggested that the medium be sent to
       the field,  preweighed,  in vials or
       capped culture tubes.  The medium
       then requires only the  addition of a
       suitable volume of distilled water-
       ethanol prior to sterilization.

      Membrane Filter Laboratory and Field Procedures
   3  Sterilization procedures in the field
      are the same as for laboratory methods.

   4  Laboratory preparation of the media,
      ready for use,  would be permissible
      provided that the required limitations
      on time and conditions of storage are

B  Operation of the Sabro Field Unit

   1  Equipment and materials

      Sabro field unit

      Membrane filters

      Absorbent pads for nutrient

      Culture containers

      M-Endo Broth  MF or L. E.S.  Endo

      Provision for heating water (optional)

      Source of electricity

   2  Procedure (Based on M-Endo Broth MF)

      a  Connect the electric cord to the
        power source  and to Sabro field
        unit.  After about 15 minutes check
        the temperature in the incubator
        drawer.  The  required temperature
        is 350 C (950F).  if the temperature
        is too low it can be increased by
        turning the thermostat adjustment
        screw  counterclockwise.  This
        screw  is located at the front on the
        recessed divider between the two
        incubator drawers.  To lower
        temperature,  turn the adjustment
        screw  clockwise.

      b  Review the  supply of expendable
        materials to be used with the unit
        and secure  replacements as needed
        (culture containers, medium,
        membrane filters, absorbent pads
        for nutrient, fuel, etc.).
   Sterilize the funnel unit by one of
   the following procedures.

   1) Immerse the equipment 2 minutes
     in boiling water.  The temperature
     should be at least 78° C (170°F).

   2) Flame-sterilize membrane filter
     holder inside and both ends of
     funnel (suggested by manufacturer).

   Lay in a row all the culture con-
   tainers to be used  in the filtration
   series,  and number the containers
   to correspond with numbers of the
   data sheet.

   Place one sterile absorbent pad in
   each culture container. Use sterile
   forceps for all manipulation of
   absorbent pads and filters.

   Using sterile pipette deliver enough
   culture medium to saturate each
   absorbent pad. The amount of
   culture medium required is approxi-
   mately 2 ml, but cannot be precisely
   stated.  Sufficient  medium should be
   applied, that when the  culture con-
   tainer is tipped,  a good-sized drop
   of culture medium freely drains out
   of the absorbent pad.

   Using sterile forceps,  place a mem-
   brane filter,  grid-side up,  on the
   MF receptacle of the funnel unit.
   Place the funnel portion over the
   membrane,  and clamp the unit with
   the spring clamp provided with the
   portable kit.
n Pour the water sample into the funnel
  using a sterile pipette or graduate.

 i   Connect the tubing of the vacuum
    pump to the receptable  on the base
    of the filter unit and draw the sample
    through the membrane.  .After all the
    sample has passed through the membra:

                                   Membrane Filter Laboratory and Field Procedures
        filter,  rinse down the sides of the funnel
        walls with at least 20 ml of sterile dilu-
        tion water.  Repeat the rinse twice after
        all the first rinse has passed through
        the filter.

     j  Disassemble the funnel unit and with
        sterile forceps transfer the membrane
        filter grid- side up to the appropriate
        culture container. The membrane
        should be "rolled on" the absorbent
        pad containing culture medium,  to
        prevent entrapment of air between
        the pad and the membrane filter.

     k  Repeat steps g - j for additional
        filtrations of the same  or different
        sampling volumes for the water
        being tested.

     1  After completion of filtration,  place
        the culture container in an inverted
        position (with membrane position
        grid-side down) in the incubator
     m After completion  of the last filtration
        from any one sample, resterilize  the
        funnel unit by one of the procedures
        described in instruction 2c.
     n  Allow the cultures to incubate
        20-24 hours.

     o  Remove the cultures from the
        incubator and count coliform colonies.
C Operation of Millipore Water Testing Kit,

  1  Supporting supplies and equipment are
     the same as for the laboratory

  2  Set the incubator voltage selector
     switch to the voltage of the available
     supply,  turn on the unit and adjust as
     necessary to establish operating
     incubator temperature at  35 + 0.5° C.

  3  Sterilize the funnel unit assembly by
     exposure to formaldehyde or by
     immersion in boiling water.  If a
     laboratory autoclave is available, this
     is preferred.
     Formaldehyde is produced by soaking
     an asbestos ring (in the funnel base)
     with methanol,  igniting,  and after a
     few seconds of burning,  closing the
     unit by placing the stainless steel
     flask over the funnel and base.  This
     results in incomplete combustion of
     the methanol, whereby formaldehyde
     is produced. Leave the  unit closed
     for 15 minutes to allow adequate
     exposure to formaldehyde.

  4  Filtration and incubation procedures
     correspond with -laboratory methods.

  5  The unit is supplied with a booklet
     containing detailed step-by-step
     operational procedures.  The worker
     using the equipment should become
     completely versed in its contents and

D Counting of Colonies on Membrane Filters

  1  Equipment and materials

     Membrane filter cultures to be

     Illumination source

     Simple lens, 2X to 6X magnification

     Hand tally (optional)

  2  Procedure

     a  Remove the cultures from the
        incubator and arrange them in
        numerical sequence.

     b  Set up illumination source as that
        light will originate from an area
        perpendicular to the plane of
        membrane filters being examined.
        A small fluorescent lamp is ideal
        for the purpose.  It is highly
        desirable that a simple lens be
        attached to the light source.

     c  Examine results.  Count all coliform
        and  noncoliform colonies.  Coliform
        colonies have a "metallic" surface
        sheen .under reflected light, which
        may cover the entire  colony or may
        appear only on the center.

     Membrane filter Laboratory and Field Procedures
        Noncoliform colonies range from
        colorless to pink or red, but do not
        have the characteristic  "metallic"

        Enter the colony counts in the data

        Enter the coliform count per 100 ml
        of sample for each membrane having
        a countable number of coliform
        colonies.  Computation is as follows:

        No. coliform per 100 ml =

                1  Standard Methods for the Examination of
                     Water and Wastewater.  APHA,
                     AWWA, WPCF.  12th Edition.   1965.

                2  McCarthy, J.A.,  Delaney,  J.E. and
                     Grasso, R. J.  Measuring Coliforms
                     in Water.  Water and Sewage Works.
                     1961: R-426-31.   1961.
  No.  coliform colonies on MF
  No.  milliliters sample filtered
This outline was prepared by H. L. Jeter,
Director, National Training Center, MDS,
OWP,  EPA,  Cincinnati,  OH   45268.

                         DISSOLVED OXYGEN DETERMINATION (DO) - I

                        Winkler lodometric Titration and Azide Modification
     I  The Dissolved Oxygen determination is
     a very important water quality criteria for
     many reasons:

     A  Oxygen is an essential nutrient for all
        living organisms.   Dissolved oxygen is
        essential for survival of aerobic
        organisms and permits facultative
        organisms to metabolize more effectively.
        Many desirable varieties of macro or
        micro organisms cannot survive at
        dissolved oxygen concentrations below
        certain minimum values.  These values
        vary with the type of organisms, stage
        in their life history, activity, and other

     B  Dissolved oxygen levels may be used as
        an indicator of pollution by oxygen
        demanding wastes.  Low DO concen-
        trations are likely to be associated with
        low quality waters.

     C  The presence of dissolved  oxygen
        prevents or minimizes  the onset of
        putrefactive decomposition and the
        production of objectionable amounts of
        malodorous sulfides, mercaptans,
        amines, etc.

     D  Dissolved oxygen is essential for
        terminal stabilization wastewaters.
        High DO concentrations are normally
        associated with good quality water.

     E  Dissolved oxygen changes with respect
        to time, depth or section of a water
        mass are useful to indicate the degree
        of stability or mixing characteristics
        of that situation.

     F  The BOD or other respirometric test
        methods for water quality are commonly
        based upon the difference among an
        initial and final DO determination for a
        given sample time interval and con-
        dition.   These measurements are
        useful to indicate:
     1   The rate of biochemical activity in
         terms of oxygen demand for a
         given sample and conditions.

     2   The degree of acceptability
         (a bioassay technique) for bio-
         chemical stabilization of a given
         microbiota in response to food,
         inhibitory agents or test conditions.

     3   The degree of instability of a
         water mass on the basis of  test
         sample DO changes over an
         extended interval of time.

     4   Permissible  load variations in
         surface water or treatment units
         in terms of DO depletion versus
         time, concentration,  or ratio of
         food to organism mass,  solids, or
         volume ratios.

     5   Oxygenation requirements
         necessary  to meet the oxygen
         demand in  treatment units or
         surface water situations.

     The DO test is  the only chemical test
     included in all Water Quality Criteria,
     Federal,  State, Regional or  local.
 A   Physical Factors:
         DO solubility in water for an
         air/water system is limited to
         about 9 mg DO/liter of water  at
         200 C.  This amounts to about
         0. 0009% as  compared to 21% by
         weight of oxygen in air.

         Transfer of oxygen from air to
         water is limited by the interface
         area, the oxygen deficit, partial
         pressure, the conditions at the

Dissolved Oxygen Determination (DO) - I
       interface area, mixing phenomena
       and other items.

       Certain factors tend to confuse
       reoxygenation mechanisms of
       water aeration:

       a  The transfer of oxygen in air
          to dissolved molecular oxygen
          in water has two principal

          1)   Area of the air-water

          2)   Dispersion of the oxygen-
              saturated water at the
              interface into the body liquid.

          The first depends upon the  surface
          area of the air bubbles in the water
          or water drops in the  air; the
          second depends upon the  mixing
          energy in the liquid.  If diffusors
          are  placed in a line along the wall,
          dead spots may develop in the core.
          Different diffusor placement or
          mixing energy may improve oxygen
          transfer to the liquid two or threefold.

       b  Other variables in oxygen transfer

          3)   Oxygen deficit in  the liquid.

          4)   Oxygen content of the gas phase.

          5)   Time.

          If the first four variables are
          favorable, the process of water
          oxygenation is rapid until the liquid
          approaches saturation.   Much more
          energy and time are required to
          increase oxygen saturation from
          about 95 to 100% than  to increase
          oxygen saturation from 0 to about
   95%.  For example: An oxygen-
   depleted sample often will pick up
   significant DO during DO testing;
   changes are unlikely with a sample
   containing equilibrium amounts
   of DO.
   The limited solubility of oxygen
   in water compared to the oxygen
   content of air does not require
   the interchange of a large mass of
   oxygen per unit volume of water
   to change DO saturation.  DO
   increases from zero to 50%
   saturation are common in passage
   over a weir.

   Aeration of dirty water is practiced
   for cleanup. Aeration of clean
   water results in washing the air and
   transferring fine particulates and
   gaseous contaminants to the liquid.
   One liter of air at room temperature
   contains about 230 mg of oxygen.
   A 5 gal carboy of water with 2 liters
   of gas  space above the liquid has
   ample  oxygen  supply for equilibration
   of DO after  storage for 2 or 3 days
   or shaking for 30 sec.

   Aeration tends toward evaporative
   cooling.  Oxygen content  becomes
   higher than  saturation values at
   the test temperature, thus
   contributing to high blanks.
Oxygen solubility varies with the
temperature of the water.
Solubility at 10° C is about two
times that at 30° C.  Temperature
often contributes to DO variations
much greater than anticipated by

                                           Dissolved Oxygen Determination (DO)  - I
solubility.  A cold water often has
much more DO than the solubility
limits at laboratory temperature.
Standing during warmup commonly
results in a loss of DO due to
oxygen diffusion from the super-
saturated sample.  Samples
warmer than laboratory tempera-
ture may decrease  in volume due
to the contraction of liquid as
temperature  is lowered.  The full
bottle at higher temperature will
be partially full after shrinkage
with air  entrance around the stopper
to replace  the void. Oxygen in the
air may be transferred to  raise the
sample DO.  For example, a
volumetric flask filled to the  1000 ml
mark at  30° C will show a  water
level about 1/2 inch below the mark
when the water temperature  is
reduced to 20° C.  BOD dilutions
should be adjusted to 200C + or -
1  1/20 before filling and testing.

Water density varies with  tem-
perature with maximum water
density at 4°C.  Colder or warmer
waters tend to promote stratification
of water that interferes with
distribution of DO because the"
higher density waters tend to seek
the lower levels.

Oxygen diffusion in a water mass is
relatively slow,  hence vertical and
lateral mixing are essential to
maintain relatively uniform oxygen
concentrations in a water mass.

Increasing salt concentration
decreases  oxygen solubility
slightly but has a larger effect
upon density  stratification in a
water mass.

The partial pressure of the oxygen
in the gas above the water interface
controls the oxygen solubility
limits in the  water. For example,
the equilibrium concentration of
oxygen in water is about 9 mg DO/1
under one atmospheric pressure  of
        air, about 42 mg DO/liter in
        contact with pure oxygen and 0 mg
        DO/liter in contact with pure
        nitrogen (@  200  C).

B   Biological or Bio-Chemical Factors

    1   Aquatic  life  requires oxygen for
        respiration to meet energy
        requirements for growth, repro-
        duction, and motion.  The net
        effect is to deplete oxygen resources
        in the water at a rate controlled
        by the type,  activity,  and mass of
        living materials present, the
        availability of food and favor-
        ability of conditions.

    2   Algae, autotrophic bacteria, plants
        or other organisms capable of
        photosynthesis may use light
        energy to synthesize cell materials
        from mineralized nutrients  with
        oxygen released in process.

        a    Photosynthesis occurs only
             under the influence of adequate
             light intensity.

        b    Respiration of alga is

        c    The dominant effect in terms
             of oxygen assets or
             liabilities of alga depends upon
             algal activity,  numbers and
             light intensity.  Gross algal
             productivity contributes to
             significant  diurnal DO

    3   High rate deoxygenation commonly
        accompanies assimilation of
        readily available nutrients  and
        conversion into cell mass or
        storage  products.  Deoxygenation
        due to cell mass respiration
        commonly occurs at some lower
        rate dependent upon the nature of
        the organisms present, the  stage
        of decomposition and the degree
        of predation, lysis, mixing  and
        regrowth.   Relatively high

  Dissolved Oxygen Determination (DO) - I
         deoxygenation rates commonly are
         associated with significant growth
         or regrowth of organisms.

         Micro-organisms tend to flocculate
         or agglomerate to form settleable
         masses particularly at limiting
         nutrient levels (after available
         nutrients have been assimilated or
         the number of organisms are large
         in proportion to available food).

         a   Resulting benthic deposits
             continue to respire as bed

         b   Oxygen availability is limited
             because the deposit  is physically
             removed from the source of
             surface oxygenation and algal
             activity usually is more
             favorable near the surface.
             Stratification is likely to limit
             oxygen transfer to the bed load

         c   The bed load commonly is
             oxygen deficient  and decomposes
             by anaerobic action.

         d   Anaerobic action commonly is
             characterized by a dominant
             hydrolytic or solubilizing action
             with relatively low rate growth
             of organisms.

         e   The net effect is to produce low
             molecular weight products
             from  cell mass with a corre-
             spondingly large fraction of
             feedback of nutrients to the
             overlaying waters.  These
             lysis  products have  the effect
             of a high rate or immediate
             oxygen demand upon mixture
             with oxygen containing waters.

         f   Turbulence favoring mixing of
             surface waters and benthic
             sediments commonly are
             associated with extremely
             rapid depletion of DO.
              Recurrent resuspension of
              thin benthic deposits may
              contribute to highly erratic
              DO patterns.

          g   Long term deposition areas
              commonly act like point
              sources of new pollution as
              a result of the feedback of
              nutrients from the deposit.
              Rate of reaction may be low
              for old materials but a low
              percentage of a large mass of
              unstable material may produce
              excessive oxygen demands.

      Tremendous DO variations are likely
      in a polluted water in reference to
      depth, cross section or time of day.
      More stabilized waters tend to show
      decreased DO variations although it is
      likely that natural deposits such as leaf
      mold will produce differences related
      to depth in stratified deep waters.

 The basic Winkler procedure (1888) has been
 modified many times to improve its work-
 ability in polluted waters.  None of these
 modifications have been completely
 successful.  The most useful modification
 was proposed by Alsterberg and consists of
 the addition of sodium azide to control
 nitrite interference during the iodometric
 titration.  The Azide modification of the
 iodometric titration is recommended as
 official by the  EPA-OWP Quality Control
 Committee for relatively clean waters.

 A  Reactions

      1   The determination of DO involves
          a complex series of interactions
          that must be  quantitative to provide
          a valid DO result.  The number of
          sequential reactions also compli-
          cates interference control.  The
          reactions will be presented first
          followed  by discussion of the
          functional aspects.

                                                 Dissolved Oxygen Determination (DO) - I
MnSO  + 2 KOH -»Mn(OH)  + K  SO       (a)
     4                  Li    &  4
2 Mn(OHL + O,  -"2 MnO(OH)
MnO(OH)  + 2 H SO — Mn(SO  )  + 3H O (c)
        &      £   ™t         ft £»     £*
     2 KI -- MnSO
*a2S2°3^  Na2S4°6

 Reaction sequence
       The series of reactions involves
       five different operational steps in
       converting dissolved oxygen in the
       water into a form in which it can
       be measured.
           I —>• Thiosulfate (thio) or
           phenylarsine oxide (PAO)

       b   All added reagents are in excess
           to improve contact possibilities
           and to force the reaction toward

       The first conversion, O  -*•
       MnO(OH)  (reactions a, B) is an
       oxygen transfer operation where
       the dissolved oxygen in the water
       combines with manganous
       hydroxide to form an oxygenated
       manganic hydroxide.

       a   The manganous salt  can react
           with oxygen only in a highly
           alkaline media.

       b   The manganous salt  and alkali
           must be added  separately with
           addition below  the surface of
           the sample to minimize reaction
           with atmospheric oxygen via
           air bubbles or  surface contact.
           Reaction with sample dissolved
           oxygen is intended to occur
           upon mixing of  the reagents and
           sample after stoppering the
           full bottle (care should be used
    to allow entrained air bubbles
    to rise  to the surface before
    adding reagents to prevent
    high results due to including
    entrained oxygen).

c   Transfer  of Oxygen from the
    dissolved state to the pre-
    cipitate form involves a two
    phase system of solution and
    precipitate requiring effective
    mixing  for quantitative
    transfer.  Normally a gross
    excess  of reagents are used
    to limit mixing requirements.
    Mixing  by rapid inversion 25
    to 35 times will accomplish
    the purpose.  Less energy  is
    required by inversion 5 or  6
    times,  allowing the solids to
    settle half way  and repeat the
    process.  Reaction is rapid;
    contact is the principal
    problem in the  two phase

d   If the alkaline floe  is white,
    no oxygen is present.

Acidification (reactions c and  d)
changes the oxygenated manganic
hydroxide to manganic sulfate
which in turn  reacts with
potassium iodide to form  elemental
iodine.  Under acid conditions,
oxygen cannot react directly with
the excess manganous sulfate
remaining in solution.

Iodine (reaction e) may be titrated
with sodium thiosulfate standard
solution to indicate  the amount of
dissolved oxygen originally
present in the sample.

a   The blue  color  of the starch-
    iodine complex commonly  is
    used as an indicator.  This
    blue color disappears when
    elemental iodine has  been
    reacted with an equivalent
    amount of thiosulfate.

Dissolved Oxygen Determination (DO) - I
        b    Phenylarsine oxide solutions are
             more expensive to obtain but
             have better keeping qualities
             than thiosulfate solutions.
             Occasional use, field operations
             and situations where it is not
             feasible to calibrate thio
             solutions regularly, usually
             encourage use of purchased
             PAO reagents.

        For practical purposes the  DO
        determination scheme involves  the
        following operations.

        a    Fill a 300 ml bottle* under
             conditions minimizing DO
             changes. This means that  the
             sample bottle must be flushed
             with test solution to displace
             the air  in the bottle  with water
             characteristic of the tested

             *DO test bottle volumes should
             be  checked -  discard those
             outside of the limits of 300 ml
             + or - 3 ml.

        b    To the filled bottle:

             1)   Add MnSO  reagent (2  ml)

             2)   Add KOH, KI,  NaN  reagent
                 (2 ml)
                 Stopper,  mix by inversion,
                 allow to settle half way and
                 repeat the operation.
                 Highly saline test waters
                 commonly settle very
                 slowly at this stage and
                 may not settle to the half
                 way point in the time

        c    To the alkaline mix  (settled
             about half way) add 2 ml of
             sulfuric acid, stopper and mix.

        d    Transfer the  contents of the
             bottle to a 500 ml Erlenmeyer
             flask and titrate with 0.0375
             Normal Thiosulfate*.   Each
             ml of reagent used represents
             1 mg of DO/liter of sample.
              The same thing applies for
              other sample volumes when
              using an appropriate titrant
              normality such as:

              1)  For a 200 ml sample,  use
                  0.025 N Thio

              2)  For a 100 ml sample,  use
                  0.0125 N Thio

              *EPA-OWP Method

          The addition of the first two DO
          reagents,  (MnSO4 and the KOH, KI
          and NaN,  solutions) displaces an
          equal quantity of the sample.  This
          is not the  case when acid is added
          because the clear liquid above the
          floe does not contain dissolved
          oxygen as all of it should be con-
          verted to the particulate MnO(OH) .
          Some error is introduced  by this
          displacement of sample during
          dosage of  the first two reagents.
          The error upon addition of 2 ml of
          each reagent to a 300 ml sample
          is JL  X  100 or 1.33% loss in DO.
          This may  be corrected by an
          appropriate factor or by adjust-
          ment of reagent normality.  It is
          generally  considered small in
          relation to other errors in sampling,
          manipulation and interference,
          hence this error may be recognized
          but not corrected.

          Reagent preparation and pro-
          cedural details can be found in
          reference 1.
IV    The sequential reactions for the
 Chemical DO determination provides
 several situations where significant inter-
 ference may occur in application on
 polluted water,  such as:

 A    Sampling errors may not be strictly
      designated as interference but have the
      same effect of changing sample DO.
      Inadequate flushing of the bottle con-
      tents or exposure to air may raise the
      DO of low oxygen samples or lower the
      DO of supersaturated samples.

                                                  Dissolved Oxygen Determination (DO) - I
B  Entrained air may be trapped in a DO
   bottle by:

   1   Rapid filling of vigorously mixed
       samples without allowing the
       entrained air to escape before
       closing the bottle and adding DO
                                                  benthic residues.  It would be expected
                                                  that benthic residues would tend toward
                                                  low results because of the reduced iron
                                                  and sulfur content - they commonly
                                                  favor high results due  to other factors
                                                  that react more  rapidly, often giving
                                                  the same effect as in uncontrolled
                                                  nitrite interference during titration.
   2   Filling a bottle with low temperature
       water holding more DO than that in
       equilibrium after the samples warm
       to working temperature.

   3   Aeration is likely to cool the sample
       permitting more DO to be introduced
       than can be held at  the room or
       incubator temperatures.

   4   Samples warmer than working
       incubator temperatures will be
       only partially full at equilibrium

       Addition of DO reagents results in
       reaction with dissolved or entrained
       oxygen.  Results for  DO are invalid
       if there is any evidence of gas
       bubbles in the sample bottle.

   The DO reagents respond to any oxidant
   or reductant  in the sample capable of
   reacting within the time allotted.  HOC1
   of H2O2 may raise the DO titration
   while H2S,
           4 SH  may react with sample
oxygen to lower the sample titration.
The items mentioned react rapidly and
raise or lower the DO result promptly.
Other items such as Fe    or SO3 may
or may  not react completely within the
time allotted for reaction.  Many
organic materials or complexes from
benthic  deposits may have an effect upon
DO results that are difficult to predict.
They  may  have one effect during the
alkaline stage to release iodine from
Kl while favoring irreversible
absorption of iodine during the acid
stage.  Degree of effect may increase
with reaction time.  It is  generally
inadvisable to use the iodometric
titration on samples containing large
amounts of organic contaminants or
                                                  Nitrite is present to some extent in
                                                  natural waters or partially oxidized
                                                  treatment plant samples.  Nitrite is
                                                  associated with a cyclic reaction during
                                                  the acid stage of the DO determination
                                                  that may lead to erroneous high results.

                                                  1   These reactions may be rep-
                                                      resented as follows:

                                                  2HN00 + 2 HI -J + 4H.O + NO   (a)
                                                       2,          £,      &      £.  £
         These reactions are time,  mixing
         and concentration dependent and
         can be minimized by rapid

    2    Sodium azide (NaN3) reacts with
         nitrite under acid conditions to
         form a combination of N? + N?O
         which effectively blocks the
         cyclic reaction by converting the
         HNO  to noninterfering compounds
         of nitrogen.

    3    Sodium azide added to fresh
         alkaline Kl reagent  is adequate to
         control interference up to about
         20 mg of HNO  - N/ liter of sample.
         The azide is unstable and grad-
         ually decomposes.  If resuspended
         benthic sediments are not detectable
         in a sample  showing a returning
         blue color,  it is likely that the
         azide has decomposed in the
         alkaline Kl azide reagent.

    Surfactants, color and Fe+++ may
    confuse endpoint detection if present
    in significant quantities.

Dissolved Oxygen Determination (DO) - I
 F Polluted water commonly contains
    significant interferences such as C.
    It is advisable to use a membrane
    protected sensor of the electronic type
    for DO determinations in the presence
    of these types of interference.

 G The order of reagent addition and prompt
    completion of the DO determination is
    critical.  Stable waters may give valid
    DO results after extended delay of
    titration during the acidified stage.  For
    unstable water,  undue delay at any stage
    of processing accentuates interference

This outline contains significant materials
from previous outlines by J.  W. Mandia.
Review and comments by C.  R. Hirth and
R. L.  Booth are greatly appreciated.


1   Methods for Chemical Analysis of
    Water and Wastes, EPA-AQCL,
    Cincinnati,  OH, July 1971.

This outline was prepared by  F.  J.  Ludzack,
Chemist.  National Training Center,
 MDS,  OWP,  EPA, Cincinnati, OH  45268.

                            ELECTRONIC MEASUREMENTS

A  Electronic measurement of DO is attractive
   for several reasons:

   1  Electronic methods are more readily
      adaptable for automated analysis, con-
      tinuous recording,  remote sensing or

   2  Application of electronic methods with
      membrane protection of sensors affords
      a high degree of interference control.

   3  Versatility of the electronic system
      permits design for a particular measure-
      ment, situation or  use.

   4  Many more determinations per man-
      hour are possible with a minor expend-
      iture of time for calibration.

B  Electronic methods of analysis impose
   certain restrictions upon the analyst to
   insure that the  response does,  in fact,
   indicate the item sought.

   1  The ease of  reading the indicator tends
      to produce a false sense of security.
      Frequent and careful calibrations are
      essential to  establish workability of the
      apparatus and validity of its response.

   2  The use of electronic devices requires
      a greater degree of competence on the
      part of the analyst.  Understanding of
      the behavior of oxygen must be supple-
      mented by an understanding of the
      particular instrument and its behavior
      during use.

C  Definitions

   1  Electrochemistry - a branch of chemistry
      dealing with relationships between
      electrical and chemical changes.
                                                    Electronic measurements or electro-
                                                    metric procedures - procedures using
                                                    the measurement of potential differences
                                                    as an indicator of reactions taking
                                                    place at an electrode or plate.

                                                    Reduction - any process in which one
                                                    or more electrons are added to an atom
                                                    or an ion, such as O_ + 2e  —»  20  !
                                                    The oxygen has been reduced.

                                                    Oxidation - any process in which  one
                                                    or more electrons are removed from
                                                    an atom or an ion, such as Zno - 2e
                                                    -»  Zn+2. The zinc has been oxidized.

                                                    Oxidation - reduction reactions - in a
                                                    strictly chemical reaction,  reduction
                                                    cannot occur  unless an equivalent
                                                    amount of some oxidizable substance
                                                    has been oxidized.  For example:
                                                    2H. - 4e  *^ 4H    hydrogen oxidized
^ 20~2
oxygen reduced
                                                    Chemical reduction of oxygen may also
                                                    be accomplished by electrons supplied
                                                    to a noble metal electrode by a battery
                                                    or other  energizer.

                                                    Anode - an electrode at which oxidation
                                                    of some reactable substance occurs.

                                                    Cathode - an electrode at which
                                                    reduction of some reactable substance
                                                    occurs.  For example in I. C. 3, the
                                                    reduction of oxygen occurs at the

                                                    Electrochemical reaction - a reaction
                                                    involving simultaneous conversion of
                                                    chemical energy into  electrical energy
                                                    or the reverse.  These  conversions are

  Dissolved Oxygen Determination - II
       equivalent in terms of chemical and
       electrical energy and generally are

    9  Electrolyte a solution, gel,  or mixture
       capable of conducting electrical energy
       and serving as a reacting media for
       chemical changes.  The electrolyte
       commonly contains an appropriate
       concentration of selected mobile ions
       to promote the desired reactions.

   10  Electrochemical cell - a device  con-
       sisting of an electrolyte in which 2
       electrodes are immersed and connected
       via an external metallic conductor.
       The electrodes may be in separate
       compartments connected by tube con-
       taining electrolyte to complete the
       internal circuit.

       a Galvanic (or voltaic) cell - an
         electrochemical cell operated in
         such a way as to produce electrical
         energy from a chemical change,
         such as a battery (See Figure 1).
         Polarographic (electrolytic) cell -
         an electrochemical cell operated in
         such a way as to produce a chemical
         change from electrical energy
         (See Figure 2).
                                                               POLAROGRAPHIC CELL

                                                                     figure 2
              GALVANIC CELL
                  figure 1
D  As indicated in I. C. 10 the sign of an
   electrode may change as a result of the
   operating mode.  The conversion by the
   reactant of primary interest at a given
   electrode therefore designates terminology
   for that electrode and operating mode.
   In electronic oxygen analyzers,  the
   electrode at which oxygen reduction occurs
   is designated the cathode.

E  Each cell type has characteristic advantages
   and limitations.  Both may be used

   1 The galvanic  cell depends  upon
     measurement of electrical energy
     produced as a result of oxygen

                                                       Dissolved Oxygen Determination - II
   reduction.  If the oxygen content of the
   sample is negligible, the measured
   current is very low and indicator driving
   force is negligible,  therefore response
   time is longer.

2  The polarographic cell uses a standing
   current to provide energy for oxygen
   reduction.  The indicator  response
   depends upon a change  in the standing
   current as a result of electrons
   released during oxygen reduction.
   Indicator response time therefore  is
   not dependent upon oxygen concentration.

3  Choice may depend upon availability,
   habit, accessories, or the situation.
   In each case it is necessary to use
   care and judgment both in selection
   and use for the objectives desired.

 A  Reduction of oxygen takes place in two
    steps as shown in the following equations:
    it £t
              2e -> 2OH
    Both equations require electron input to
    activate reduction of oxygen.  The first
    reaction is more important for electronic
    DO measurement because it occurs at a
    potential (voltage) which is below that
    required to activate reduction of most
    interfering components (0.3 to 0.8 volts
    relative to the saturated calomel electrode •
    SCE).   Interferences that may be reduced
    at or below that required for oxygen
    usually are present at lower concentrations
    in water or may be minimized by the use
    of a selective membrane or other means.
    When reduction occurs, a definite quantity
    of electrical energy is produced that is
    proportional to the quantity of reductant
    entering the reaction.  Resulting current
    measurements thus are more specific for
    oxygen reduction.

B  Most electronic measurements of oxygen
    are based upon one of two techniques for
    evaluating oxygen  reduction in line with
                                                     equation II.A. 1.  Both require activateig
                                                     energy,  both produce a current propr  -
                                                     tional to the quantity of reacting reductant.
                                                     The techniques differ in the means of
                                                     supplying the activating potential; one
                                                     employs a source of outside energy, the
                                                     other uses spontaneous energy produced
                                                     by the electrode pair.

                                                     1  The polarographic oxygen  sensor
                                                        relies upon an outside source of
                                                        potential to activate oxygen reduction.
                                                        Electron gain by oxygen changes the
                                                        reference voltage.
   a  Traditionally,  the dropping mercury
      electrode (DME) has been used for
      polarographic  measurements. Good
      results have been obtained for DO
      using the DME but the difficulty of
      maintaining a constant mercury drop
      rate, temperature control, and
      freedom from turbulence makes it
      impractical for field use.

   b  Solid electrodes are attractive
      because greater surface area
      improves sensitivity.  Poisoning
      of the  solid surface  electrodes is
      a recurrent problem.  The use of
      selective membranes over noble
      metal  electrodes has minimized
      but not eliminated electrode con-
      tamination.  Feasibility has been
      improved sufficiently to make this
      type popular for regular use.

2  Galvanic  oxygen electrodes consist of
   a decomposable anode and a noble
   metal cathode in a suitable electrolyte
   to produce activating energy for oxygen
   reduction (an air cell or battery).  Lead
   is commonly used as the anode because
   its decomposition potential favors
   spontaneous reduction of oxygen. The
   process is continuous as long as lead
   and oxygen are in contact in the electrolyte
   and the electrical energy released at
   the cathode may be dissipated by an
   outside circuit. The anode may be
   conserved by limiting oxygen availability.
   Interrupting the outside circuit may
   produce erratic behavior for  a time
   after reconnection. The resulting

 Dissolved Oxygen Determination - II
       current produced by oxygen reduction
       may be converted to oxygen concen-
       tration by use of a sensitivity coefficient
       obtained during calibration.  Provision
       of a pulsed or interrupted signal makes
       it possible to amplify or control the
       signal and adjust it for direct reading
       in terms of oxygen concentration or to
       compensate for temperature effects.
 A  Polarographic or galvanic DO instruments
    operate as a result of oxygen partial
    pressure at the sensor surface to produce
    a signal characteristic of oxygen reduced
    at the cathode of some electrode pair.
    This signal is conveyed to an indicating
    device with or without modification for
    sensitivity and temperature or other
    influences  depending upon the  instrument
    capabilities and intended use.

    1  Many approaches and refinements  have
       been used to improve workability,
       applicability, validity, stability and
       control  of variables.  Developments
       are continuing.  It is possible to produce
       a device capable of meeting any reasonable
       situation, but situations differ.

    2  Most commercial DO instruments  are
       designed for use under specified con-
       ditions.  Some are more versatile than
       others.   Benefits are commonly reflected
       in the price.  It is essential to deter-
       mine the requirements of the measure-
       ment situation and objectives for use.
       Evaluation of a given instrument in
       terms of sensitivity, response time,
       portability, stability,  service
       characteristics,  degree of automation,
       and consistency are used for judgment
       on a cost/benefit basis to select the
       most acceptable unit.

 B  Variables Affecting Electronic DO

    1  Temperature affects the  solubility of
       oxygen,  the magnitude of the resulting
       signal and the permeability of the
   protective membrane.  A curve of
   oxygen solubility in water versus
   increasing temperature may be concave
   downward while a similar curve of
   sensor response versus temperature
   is concave upward.  Increasing
   temperature decreases oxygen solubility
   and increases probe sensitivity and
   membrane permeability. Thermistor
   actuated compensation of probe
   response based upon a linear relation-
   ship or average of oxygen solubility
   and electrode sensitivity is not precisely
   correct as the maximum spread in
   curvature occurs at about 17° c with
   lower deviations from linearity above
   or below that temperature.   If the
   instrument  is calibrated at  a temperature
   within + or  -  5° C of working temperature,
   the  compensated readout is likely to be
   within 2% of the real value.  Depending
   upon probe  geometry,  the laboratory
   sensor may require 4 to 6% correction
   of signal per o c change in liquid

2  Increasing pressure tends to increase
   electrode response by compression
   and contact effects upon the electrolyte,
   dissolved gases and electrode surfaces.
   As long as entrained gases  are not
   contained in the electrolyte or under
   the  membrane,  these effects are

   Inclusion of entrained gases results in
   erratic response that increases with
   depth of immersion.

3  Electrode sensitivity changes occur as
   a result of the nature and concentration
   of contaminants at the electrode sur-
   faces and possible physical chemical or
   electronic side reactions produced.
   These may  take the  form of a physical
   barrier,  internal short, high residual
   current,  or chemical changes in the
   metal surface.  The membrane is
   intended to  allow dissolved  gas pene-
   tration but to exclude passage of ions
   or particulates.  Apparently some ions
   or materials producing extraneous ions
   within the electrode vicinity are able
   to pass in limited amounts which

                                                    Dissolved Oxygen Determination - II
   become significant in time.   Dissolved
   gases include  1) oxygen, 2) nitrogen,
   3) carbon dioxide, 4) hydrogen sulfide,
   and certain others.  Item 4 is likely to
   be a major problem.  Item 3 may pro-
   duce deposits  in alkaline media; most
   electrolytes are alkaline or tend to
   become so in line with reaction H.A. 1.
   The usable life of the sensor varies
   with the type of electrode system,
   surface area,  amount of electrolyte
   and type,  membrane  characteristics,
   nature of the samples to which the
   system is exposed and the length of
   exposure.  For example,  galvanic
   electrodes used in activated sludge
   units showed that the time between
   cleanup was 4  to 6 months for electrodes
   used for intermittent daily checks of
   effluent DO; continuous use in the mixed
   liquor required electrode cleanup in 2
   to 4 weeks.  Each electrometric cell
   configuration and operating mode has
   its own response  characteristics.
   Some are more stable than others.
   It is necessary to check calibration
   frequency required under conditions
   of use as none of them will maintain
   uniform response indefinitely.  Cali-
   bration before and after daily use is

4  Electrolytes may consist of solutions
   or gels of ionizable materials such as
   acids,  alkalies or salts.  Bicarbonates,
   KC1 and KI are frequently used.  The
   electrolyte is the transfer and reaction
   media, hence, it necessarily becomes
   contaminated before  damage to the
   electrode surface may occur.  Electro-
   lyte concentration, nature, amount and
   quality affect response time, sensitivity,
   stability, and specificity of the sensor
   system.  Generally a small quantity of
   electrolyte gives a shorter response
   time and higher sensitivity but  also may
   be affected to a greater extent by a
   given quantity  of contaminating sub-

5  Membranes may consist of teflon,
   polyethylene, rubber, and certain
   other polymeric films.  Thickness
   may vary from 0.5 to 3 mils (inches X
   1/1000).  A thinner membrane  will
   decrease response time and increase
   sensitivity but is less selective and
   may be ruptured more easily.  The
   choice of material and its uniformity
   affects response time, selectivity and
   durability.  The area of the membrane
   and its permeability are directly
   related to the quantity of transported
   materials that may produce a signal.
   The permeability of the membrane
   material is related to temperature and
   to residues accummulated on the
   membrane surface or interior.  A
   cloudy membrane usually  indicates
   deposition and more or less loss of

6  Test media characteristics  control the
   interval of usable life between cleaning
   and rejuvenation for any type of
   electrode.  More frequent cleanup is
   essential in low quality waters than for
   high quality waters.  Reduced sulfur
   compounds are among the more
   troublesome contaminants.   Salinity
   affects the partial pressure of oxygen
   at any given temperature.  This effect
   is small compared to most other
   variables but is significant if salinity
   changes by more than 500 mg/1.

7  Agitation of the sample in the vicinity
   of the electrode is important because
   DO is reduced at the cathode. Under
   quiescent conditions a gradient in
   dissolved oxygen content would be
   established on the sample side of the
   membrane as well as on the electrode
   side, resulting in atypical response.
   The sample should be agitated
   sufficiently to deliver a representative
   portion of the main body of the liquid
   to the outer face of the membrane.
   It is commonly observed that no
   agitation will result in a very low or
   negigible response after a short period
   of time.  Increasing agitation will cause
   the response to rise gradually until
   some minimum liquid velocity is reached
   that will not cause a further  increase
   in response with increased mixing
   energy.  It is important to check
   mixing velocity to reach a stable high
   signal that is independent  of a reasonable
   change in sample mixing.   Excessive

Dissolved Oxygen Determination - II
      mixing may create a vortex and expose
      the sensing surface to air rather than
      sample liquid.  This should be avoided.
      A linear liquid velocity of about 1 ft/sec
      at the sensing surface is usually

   8  DO sensor response represents a
      potential or current signal in the
      milli-volt or  milli-amp  range in a
      high resistance system.  A high quality
      electronic instrument is essential to
      maintain a usable signal-to-noise ratio.
      Some of the more common difficulties

      a Variable line voltage or low batteries
        in amplifier  power circuits.

      b Substandard  or unsteady amplifier
        or resistor components.

      c Undependable contacts or junctions
        in the sensor, connecting cables,  or
        instrument control circuits.

      d Inadequately shielded electronic

      e Excessive  exposure to moisture,
        fumes or chemicals in the wrong
        places lead to stray currents,
        internal shorts or other malfunction.

   Desirable Features in a Portable DO

   1  The unit should include steady state
      performance  electronic  and indicating
      components in a convenient but sturdy
      package that is  small enough to carry.

   2  There should  be provisions for addition
      of special accessories such as bottle
      or field sensors, agitators, recorders,
      line extensions, if needed for specific
      requirements.  Such additions should
      be readily attachable and detachable
      and maintain  good working characteristics.

   3  The instrument  should include a
      sensitivity adjustment which upon
      calibration will  provide for direct
      reading in terms of mg of DO/liter.
   4  Temperature compensation and temp-
      erature readout should be incorporated.

   5  Plug in contacts should be positive,
      sturdy,  readily cleanable and situated
      to minimize contamination.  Water
      seals should be provided where

   6  The sensor should be suitably designed
      for the purpose intended  in terms of
      sensitivity, response, stability, and
      protection during  use.  It should be
      easy to clean,  and reassemble for use
      with a minimum loss of service time.

   7  Switches,  connecting plugs,  and con-
      tacts preferably should be located on
      or in the instrument box  rather than
      at the "wet" end of the line near the
      sensor.  Connecting cables should be
      multiple strand to minimize separate
      lines.  Calibration controls should be
      convenient but designed so that it is
      not likely that they will be inadvertently
      shifted during use.

   8  Agitator accessories for  bottle use
      impose special problems because they
      should be small,  self contained,  and
      readily detachable but sturdy enough
      to give positive agitation  and electrical
      continuity in a wet zone.

   9  Major load batteries  should be
      rechargeable or readily replaceable.
      Line operation should be  feasible
      wherever possible.

  10  Service  and replacement parts avail-
      ability are a primary consideration.
      Drawings, parts identification and
      trouble shooting memos should be
      incorporated with applicable operating
      instructions in the instrument manual
      in an informative  organized form.

D  Sensor and Instrument Calibration

   The instrument box is likely to have some
   form of check to verify electronics,
   battery or other power supply conditions
   for use.  The sensor commonly is not
   included in this check.  A known reference

                                                     Dissolved Oxygen Determination - II
sample used with the instrument in an
operating mode is the best available
method to compensate for sensor variables
under use conditions.  It is advisable to
calibrate before and after daily use under
test conditions.  Severe conditions,changes
in conditions,  or possible damage call for
calibrations during the use period.  The
readout scale  is likely to be labeled -
calibration is  the basis for this label.

The following  procedure is recommended:

1  Turn the instrument on and allow it to
   reach a stable condition.  Perform the
   recommended instrument check as
   outlined in  the operating manual.

2  The instrument check usually includes
   an electronic zero correction. Check
   each instrument against the readout
   scale with the sensor immersed in an
   agitated solution of sodium  sulfite
   containing sufficient cobalt  chloride to
   catalyze the reaction of sulfite and
   oxygen.  The indicator should stabilize
   on the zero reading.  If it does not,  it
   may be the result of residual or stray
   currents, internal shorting in the
   electrode,  or membrane rupture.
   Minor adjustments may be made using
   the indicator rather than the electronic
   controls.  Serious imbalance requires
   electrode reconditioning if the electronic
   check is O.K.  Sulfite must be carefully
   rinsed from the sensor until the readout
   stabilizes to prevent carry over to the
   next sample.

3  Fill two DO bottles with replicate
   samples of clarified water similar to
   that to be tested.   This water should
   not contain significant test interferences.

4  Determine the DO in one by the azide
   modification of the iodometric titration.

5  Insert a magnetic stirrer in the other
   bottle or use a probe agitator.  Start
   agitation after insertion of the sensor
   assembly and note the point of
       a  Adjust the instrument calibration
          control if necessary to compare
          with the titrated DO.

       b  If sensitivity adjustment is not
          possible,  note the instrument
          stabilization point and designate
          it as ua.  A sensitivity coefficient,
            is equal to rrrr where DO is  the

          titrated value for the sample on
          which ua was obtained. An unknown
          DO then becomes DO = — .  This
          factor is applicable as long as the
          sensitivity does not change.

       Objectives of the test program and the
       type of instrument influence  calibration
       requirements.   Precise work may
       require calibration at 3 points in the
       DO range of  interest  instead of at zero
       and high range DO.  One  calibration
       point frequently may be adequate.

       Calibration of a DO sensor in air is a
       quick test for possible changes in
       sensor response.  The  difference in
       oxygen content of air and of water  is
       too large for air calibration to be
       satisfactory  for precise calibration
       for use in water.
IV  This section reviews characteristics of
  several sample laboratory instruments.
  Mention of a soecific instrument does not
  imply FWQA  endorsement or recommendation.
  No attempt has been made to include all the
  available  instruments; those described are
  used to indicate the approach used at one
  stage of development which may or may not
  represent the current available model.

  A  The electrode described by Carrit and
    Kanwisher (1) is illustrated in Figure 3.
    This electrode was an early example of
    those using a membrane.   The anode was
    a silver  - silver oxide reference cell with
    a platinum disc cathode (1-3 cm diameter).
    The salt bridge consisted of N/2 KC1 and

Dissolved Oxygen Determination - II
   KOH.  The polyethylene membrane was
   held in place by a retaining ring.  An
   applied current was used  in a polarographic
   mode.  Temperature effects were relatively
   large.  Thermistor  correction was studied
   but not integrated with early models.
                        — Silver Ring

          • Platinum Disk t—Electrolyte Layer

                Figure 3
B  The Beckman oxygen electrode is another
   illustration of a polarographic DO sensor
   (Figure 4).  It consists of a gold cathode,
   a silver anode, an electrolytic gel con-
   taining KC1,  covered by a teflon membrane.
   The instrument has a temperature readout
   and compensating thermistor, a source
   polarizing  current, amplifier with signal
   adjustment and a readout DO scale with
   recorder contacts.
   A-mMf •
                                   The YSI Model 51 (3) is iUustrated in
                                   Figure 5.  This is another form of
                                   polarographic DO analyzer.   The cell
                                   consists of a silver anode coil, a gold
                                   ring cathode and a KC1 electrolyte with
                                   a teflon membrane.  The instrument has
                                   a sensitivity adjustment, temperature  and
                                   DO readout.  The model 51 A has temp-
                                   erature compensation via  manual preset
                                   dial.  A field probe and bottle probe are
                                                                YSI Model 51 DO Sensor
                                 Anode  Coil
                                 Cathode Ring—rir
                                                                        Fiflure 5
                                D The Model 54 YSI DO analyzer (4) is based
                                  upon the same electrode configuration but
                                  modified to include automatic temperature
                                  compensation, DO readout, and recorder
                                  jacks.  A motorized agitator bottle probe
                                  is available for the Model 54 (Figure 6).
                                                          Agitator Mora

                                                        Dissolved Oxygen Determination - II
E  The Galvanic Cell Oxygen Analyzer (7, 8)
   employs an indicator for proportional DO
   signal but does not include thermistor
   compensation or signal adjustment.
   Temperature readout is provided.  The
   sensor includes a lead anode ring, and
   a silver cathode with KOH electrolyte
   (4 molar) covered by a membrane film
   (Figure 7).

       Precision Galvanic Cell Oxygon Probe
                             Thermiltor Cablo
                             Topirad Settion
                            to Fit BOD Botlloi
                            Plaittc Membrane
                             Retainer Ring

                            Lead Anode Ring
Silver Cathode
Polyethylene Membrane
F The Weston and Stack Model 300 DO
   Analyzer (8) has a galvanic type sensor
   with a pulsed current amplifier adjustment
   to provide for signal and temperature
   compensation.   DO and temperature
   readout is provided.  The main power
   supply is a rechargeable battery.  The
   sensor (Figure 8) consists of a lead anode
   coil recessed in the electrolyte cavity
   (50% KI) with a platinum cathode in the tip.
   The sensor  is covered with a teflon mem-
   brane.  Membrane  retention by rubber
   band or by a plastic retention ring may be
   used for the  bottle agitator  or depth
   sampler respectively.  The thermistor
   and agitator  are mounted in a sleeve that
   also provides protection for the membrane.
                                                G The EIL Model 15 A sensor is illustrated
                                                  in Figure 9.  This is a galvanic cell with
                                                  thermistor activated temperature com-
                                                  p2nsation and readout.  Signal adjustment
                                                  is provided.  The illustration shows an
                                                  expanded scheme of the electrode which
                                                  when assembled  compresses into a  sensor
                                                  approximating 5/8 inch diameter and 4 inch
                                                  length exclusive  of the  enlargement at the
                                                  upper end.  The  anode  consists of com-
                                                  pressed lead shot in a replaceable capsule
                                                  (later models used fine lead wire coils),
                                                  a perforated silver cathode sleeve around
                                                  the lead is covered by a membrane  film.
                                                  The electrolyte is saturated potassium
                                                  bicarbonate.  The large area  of lead
                                                  surface, silver and membrane provides
                                                  a current response of 200 to 300 micro-
                                                  amperes in oxygen saturated water  at
                                                  200 C for periods of up to 100 days use (8).
                                                  The larger electrode displacement favors
                                                  a scheme described by Eden (9) for
                                                  successive DO readings for BOD purposes.
V   Table 1 summarizes major characteristics
 of the sample DO analyzers described in
 Section IV.  It must be noted that an ingenious
 analyst may adapt any one of these for special
 purposes on a do-it-yourself program.  The
 sample instruments are mainly designed for
 laboratory or portable  field use.  Those
 designed for field monitoring purposes may
 include similar designs or  alternate designs
 generally employing larger anode, cathode,
 and electrolyte  capacity to  approach better
 response stability with some sacrifice in
 response time and sensitivity.  The  electronic
 controls, recording,  telemetering,  and
 accessory apparatus  generally are semi-
 permanent installations of a complex nature.

                                               This outline contains certain materials from
                                               previous outlines by D. G.  Ballinger,
                                               N.C. Malof, andJ.W. Mandia.  Additional
                                               information was  provided by C.R.  Hirth,
                                               C.N. Shadix, D.F. Krawczyk, J. Woods,
                                               and others.

Dissolved Oxygen Determination -
      WESTON  &  STACK
          DO  PROBE

                CORD RESTRAINER

                 SERVICE CAP

                 PROBE SERVjCE  CAP


                PROBE BODY

                PLATINUM CATHODE

                CONNECTOR PINS

                 PIN  HOUSING

                 LEAD ANODE

                              Figure 8

     Cable Sealing
        A 15017
                           'O' Ring
'O' Ring
                                            Model A15A ELECTRODE COMPONENT PARTS
              Lead Anode
                                                                            Membrane Securing
                                                                                 'O' Ring
'O' Ring
Membrane— Securing
      'O' Ring
                                                           Silver Cathode
                                                                                                   Filler Screw
                                              A -150140
                                          (With Sleeve S24)
                                                                               Illllll Illlllll
                          'O' Ring
'O' Ring
                                                      End Cap
               'O' Ring
                      Note: Red wire of cable connects to Anode Contact Holder

                            Black wire of cable connects to Anode Contact

                            Membrane  not shown E. I. L. part number T221
                                                       Figure 9

Dissolved Oxygen Determination - II
                                         TABLE 1

Carrit & silver -
Kanwisher silver ox.
Beckman Aq
Yellow Springs Ag
51 coil
Cathode Elec
DO Temp.
Sig. Comp. Accessories for
Type Membr Adj. Temp. Rdg. which designed
pol polyeth no
pol- teflon yes
pol teflon yes
Recording temp.
& signal adj. self
field and bottle
Yellow Springs
*Pol - Polarographic (or amperimetric)
 Galv - Galvanic (or voltametric)
recording field
bottle & agitator
Weston &

a git. probe
depth sampler
field bottle &
agitator probe
field bottle &
agitator probe

1  Carrit, D.E. and Kanwisher, J.W.
     Anal. Chem.   31:5.   1959.

2  Beckman Instrument Company.   Bulletin
     7015, A Dissolved Oxygen Primer,
     Fuller-ton, CA.   1962.

3  Instructions  for the  YSI Model 51 Oxygen
     Meter,  Yellow Springs Instrument
     Company,  Yellow Springs, OH 45387.

4  Instructions  for the  YSI Model 54 Oxygen
     Meter,  Yellow Springs Instrument
     Company,  Yellow Springs, OH 45387.
5  Technical Bulletin TS-68850 Precision
     Scientific Company,  Chicago,  IL 60647.

6  Mancy, K.H.,  Okun, D.A.  and Reilley,
     C.N.  J. Electroanal. Chem.  4:65.

7  Instruction Bulletin, Weston and Stack
     Model 300 Oxygen Analyzer.  Roy F.
     Weston,  West Chester,  PA  19380.

8  Briggs, R.  and Viney, M.   Design and
     Performance of Temperature Com-
     pensated Electrodes for Oxygen
     Measurements.  Jour, of Sci.
     Instruments  41:78-83.   1964.

                                                       Dissolved Oxygen Determination - II
Eden, R.E.   BOD Determinations Using
   a Dissolved Oxygen Meter.  Water
   Pollution Control,  pp. 537-539.  1967.

Skoog, D.A. and West, D.M.   Fundamentals
   of Analytical Chemistry.  Holt,
   Rinehart & Winston, Inc.   1966.
11  FWPCA Methods for Chemical Analysis of
      Water  and Wastes.  FWPCA Div. of
      Water  Quality Research Analytical
      Quality Control Laboratory, Cincinnati,
      OH.  p. 65-68.   November 1969.
                                                This outline was prepared by F. J. Ludzack,
                                                Chemist,  National Training Center, DTTB . MDS,
                                                Environmental Protection Agency, WQO,
                                                Cincinnati, OH  45268 and Nate Malof,  Chemist
                                                National Field Investigations Center,
                                                Environmental Protection Agency, WQO,
                                                Cincinnati, OH.


A  The BOD procedure for treatment plant
   operation is a compromise between what
   is sought and what may be obtained.  The
   five-day incubation (or BOD,.) is one of the

B  Most treatment plants have been designed
   on a BOD or BOD   basis.  The BOD  is
   the most common basis of evaluating
   plant performance or discharges to surface
   water. This outline  and another on BOD
   variables discusses the partial response
   of the BOD,, test and means whereby the
   test may be  performed or applied more
   realistically.  A partial result is valid
   if you know the fraction of total oxygen
   demand represented  by BOD  compared
   to total demand.  Supplementary tests are
   suggested which are  useful for inter-
   pretation of BOD  results.  These  tests
   are useful to avoid many  misleading

C  The BOD  test indicates the sum of various
   chemical or biological  oxidations expressed
   in terms  of oxygen use under specified
   conditions and time.  The fraction  included
   in the five-day test may include:

   1 Oxygen used for conversion of waste -
     water  substances  into  slime organisms
     (living cells of bacteria, fungi,  yeasts,
     etc.) with partial  oxidation in process.
     This may be considered as first stage
     or  carbonaceous oxygen demand.

   2 Slime  growth tends to be associated
     with organism death and decay.   When
     the original feed has been largely
     converted to cells, remaining oxidation
     occurs by regrowth  on decay products
     and the activity of slower growing
     organisms such as nitrifiers.  This
     may be considered as  second stage or
     nitrogenous oxidation.
   3   Certain chemicals may react with
      oxygen relatively quickly.  The
      resulting use of dissolved oxygen that
      is exerted within fifteen minutes is
      considered immediate dissolved
      oxygen demand (IDOD or sometimes
      IOD).  Examples of chemicals
      associated with IDOD include but are
      not limited to hydrogen sulfide,
      mercaptans, sulfites, thiosulfates
      (Thio) and some of the reduced
      (ferrous) iron.

D  There is  no way to classify a BOD result
   in terms  of I. C. 1,  2 or  3 without   ...
   supplementary information or tests

   1   Raw wastewaters, primary  effluents,
      or process waters may become septic
      and show a significant fraction of B3
      in the  BOD result.

   2   B. 1 is likely to be the main component
      of oxygen use in a fresh wastewater as
      a result  of rapidly growing slime
      organisms and readily available foods.

   3   The BOD  of partially treated  samples,
      secondary effluents or stabilized
      surface waters may be partially or
      almost completely the result of B.2.

   4   Depending upon the past history of the
      sample the BOD  may be due to any
      one, any combination or all three of
      the stages listed in B. 1, 2 or 3.
      Interpretation may be misleading if
      you depend solely on  BOD .

   5   The BOD  test is a bottle test per-
      formed under conditions different from
      those  in  a plant or stream(3).  The
      BOD-  test bottle commonly  is not
      agitated  during incubation.  The test
      incubation is likely to contain a small
      fraction  of the number and variety of
      organisms per unit of food compared

BOD Procedures for Treatment Plant Operations
     with that in a plant treatment unit.
     The test bottle commonly isn't reseeded
     and time for adaptation is limited as
     compared with plant conditions.  The
     plant oxygen use is likely to be more
     rapid and more complete than that in
     the bottle.

   6 BOD testing presumes favorable ranges
     for the essentials of biodegradation.
     It is unlikely that all of the  sample
     components are known or that all re-
     quired conditions are at their most
     favorable level '^'and remain so during
     incubation.   Any requirement for bio-
     degradation that is too low or too high
     for BOD development will produce a
     BOD,  result that is lower than the
     plant or stream oxygen demand.

   The BOD  test cannot stand alone.  Sample
   history and background suggest that which
   may have occurred.  It is not advisable to
   presume. The following tests help to
   clarify the situation with respect to BOD
   results and total load.  These  tests
   become more important as treatment
   requirements rise.

   1 The IDOD test is important whenever
     the wastewater or process stream
     shows no DO.  It becomes more
     important as the time without DO
     increases, as the temperature rises
     and with a  rise in probability that the
     mixture contains items such as those
     in I.B.3.

   2 The total load is more important than
     the BOD  load estimate.

     a The chemical oxygen demand (COD)
        test result is a fair estimate of first
        stage oxygen demand for most
        municipal wastewaters.

     b The total organic carbon (TOC) X2.67
        is an excellent estimate  of first stage
        demand but is not likely  to be available
        at small plants.
         by a factor of 4. 57 (the oxygen
         equivalent of unoxidized nitrogen).
         The BOD  result divided by an
         estimate of total demand provides
         an estimate of the fraction  of oxygen
         demand that was included in the
         BOD. compared to that which may
         be needed for sample stabilization
         under other conditions and  extended
         time.  Two possible forms are:
                 COD+ (4. 57 XTKN)
         (2. 67 XTOC) + (4. 57 XTKN)

         all results expressed in mg/1.

         For example: a series of tests
         (in mg/1) on a river water included
         BOD  - 7  to 10,  BOD   - 25 to 35,
         COD - 50  to 85,  TKN - 15 to 25.
         Taking the lower values in the range
         and substituting  gives:
         50 + (4.57X15)   50 + 68    118

         or the information that the BOD
         of this river represented about
         6 percent of the possible oxygen
         demand in it.  This information
         made it easier to explain a complete
         oxygen deficiency in the river about
         two miles below the  cited sample

         Total,  suspended and volatile solids
         (TS, SS and VS) are  readily obtainable
         and useful means to  estimate what
         has been or remains to be done.
         The volatile solids (of TS or SS) are
         directly relatable to oxygen demand.
         Wastewater treatment is concerned
         with a reduction in sample volatile
         solids either by oxidation or take-out.
        The second stage oxygen demand may
        be estimated by determining ammonia
        plus organic nitrogen (total Kjeldahl
        nitrogen - TKN) and multiplying the

 A  Standard Incubation Bottles

                                             BOD Procedures for Treatment Plant Operations
   1  300 ml bottles with a water seal lip
      are preferred.  Reject for BOD use
      any bottles containing less than 297
      or more than 303 ml.
   2  Carefully clean new or used bottles with
      glass cleaning detergent and brushing.
      Rinse each bottle with good quality dis-
      tilled water; completely drain each
      bottle after each rinse using an upside
      down vertical position (4 to 10 rinses
      depending upon soil and cleaning agent
      used to remove it).
   3  Do not use regular BOD bottles for
      sample or reagent use.

   4  Provide wire, chain,  or other ties to
      keep properly fitted stoppers and
      bottles together.

   5  It is helpful to provide paper cups such
      as those used for coffee creamers in
      restaurant use (size to fit the bottle top)
      to decrease water seal evaporation
      during incubation.

B  Wood or wire rack to hold BOD bottles
   upside down for drainage or storage.
   Inclined pegboards are not satisfactory.

C  Air or water bath incubator large enough
   to avoid crowding during anticipated
   bottle incubation.

   1  Temperature thermostatically con-
      trolled at 20° C + or - 10 C in an parts
      of the storage area.  Air or water
      mixing is advisable.

   2  BOD incubations are intended to be in
      darkness.  Do not store reagents or
      samples in incubator space.  This will
      encourage frequent door opening.  Even
      short light periods may encourage algal
      activity in certain samples.  This  will
      raise DO and confuse the anticipated
      oxygen depletion.

D  Titration assembly and accessories for the
   azide modification of the iodometric DO.

E  An electronic DO probe fitted for bottle use
   is encouraged for routine  use.  After daily
   calibration check the probe favors more
   oxygen determinations in less time with
    less serious interference problems than
    by titration. It will be possible to deter-
    mine DO where a valid result by titration
    would be unlikely.

  F Waring blender or other mixer to break
    up clumps in samples to be subsampled
    for BOD purposes.

  G pH meter for adjustment and check of
    samples,  reagents and dilutions.

  H Pipets, burets, thermometers, graduates,
    containers adequate to facilitate operations
    intended.   Reference 4 is useful for
    identification and handling.

 A High quality water is required that does
    not introduce more than trace amounts of
    oxidizable materials or substances that
    interfere with biological stabilization.
    Copper and chlorine are common prob-
    lems; many others are possible.

    1  Block tin, stainless steel or glass
       stills are advisable.  It may be
       advisable to install an activated
       carbon column in the line ahead of
       the distilling unit to remove  chlorine
       and certain organics that would be
       transferred to the product water.
       Deionization units may be  effective.

    2  Satisfactory distilled water is  indicated
       if the BOD  for mineral fortified
       distilled water seeded with about
                                   1 to
       5 drops/liter of well stabilized river
       water is less than 0.4 mg DO; also
       that the same seeded water to which
       2 percent of a solution of 0. 15 g
       glucose and 0. 15 g glutamic acid/liter
       has a depletion of at least 4. 0 mg DO.
Mineral Supplements (Reference 1,

1  Phosphate buffer solution

2  Magnesium sulfate solution

3  Calcium chloride solution

BOD Procedures for Treatment Plant Operations
   4  Ferric chloride solution

   Ammonium chloride may be omitted from
   solution 1 if the samples contain more
   than adequate nitrogen for growth.  Most
   municipal waste waters are in this group.
   These reagents should be replaced when-
   ever growth, precipitation or contamination
   is apparent or suspected.

C  DO Reagents

D  One normal acid and alkali solutions for
   sample neutralization prior to BOD

E  Seeding material, if necessary.

   1  Most samples in wastewater treatment
      operations do not require seeding.

   2  Seeding is indicated with samples that
      have been heated,  acid,  alkali, or
      chemically treated to kill the organisms
      normally present.

   3  The seed should contain a variety of
      mixed organisms capable of starting
      BOD exertion as soon as it  is mixed
      with sample oxidizable material.
      The seed should not contain significant
      amounts of available food other than
      organisms that would favor a high seed
      BOD .

   4  The best  source of seed would be a well
      stabilized receiving water.  A well
      stabilized secondary treatment plant
      effluent would be an alternate choice.
      The amount must be determined by
      trial (usually less than one  percent).

   5  Seed corrections are questionable
     because a seed does not oxidize in the
      same manner in the presence of food
     as it does without it. Different con-
      centrations are unlikely to behave
      similarly. Don't use seeding unless
      absolutely necessary. Fresh or stale
      sewage seeds are not recommended
     because this material has not had time
     to develop populations characteristic
      of those in a treatment plant or stream.

 A The Immediate Dissolved Oxygen Demand
    (IDOD) test commonly is ignored in BOD,.
    results.  It is included in the result if
    you use a calculated initial DO.  It is not
    included if you use a determined initial DO.
    As discussed previously any fraction  of the
    oxygen demand that occurs within fifteen
    minutes of mixing is part of the IDOD.
    It is likely to be associated with any
    sample in which the DO has been
    exhausted. It is advisable to test for it
    because this demand is very rapidly
    exerted and may seriously affect oxygen
    supply and/or BOD,, results.

    1  Determine  the DO  of the sample
       (usually zero) and  the dilution water
       separately.  Mix definite proportions
       of the two.  After fifteen minutes
       determine the DO in the combination.
       Calculate what the DO should have
       been in the mixture.  Any difference
       between the calculated and determined
       value is due to experimental error or
       IDOD of the sample.

    2  Example:

       a  The sample contained no  measurable
          DO, dilution water contained 8.6 mg
          DO/liter.  Ten  percent of the sample
          was mixed with 90 percent dilution
          water.  After fifteen minutes the
          mixture indicated 3.2 mg DO/liter.

       b  Initial DO of the mixture  (no IDOD)
          should have been:

 10 parts of 0 DO  water =     0 oxygen units
 90 parts of 8.6 DO
    water              = 774.0 oxygen units

 100 parts of the mixture contains 774 oxygen
 DO per part = y   = 7. 74 mg DO/liter
          Observed DO after fifteen minutes
          = 3.2 mg DO/liter

                                             BOD Procedures for Treatment Plant Operations
Then IDOD =
   % dilution
           = (7.74 - 3.2) X100
      d  Incubate at 20° C + or -  1° C for five
        days and determine the DO final.

      e  mg BOD../liter = DO.  ... ,  - DO,.  ,
          s     5           initial      final

           = 4.54 X100  = 45 mg IDOD/liter

   3  The IDOD would have to be satisfied
      before DO for aerobic activity could
      be supplied.

   4  It is advisable to use a DO probe for
      IDOD tests.   Samples likely to show
      negligible DO are likely to contain
      serious interferences for DO titration
      which are not serious when using a
      membrane protected DO  probe.

   5  In BOD work,  try a calculated and
      determined initial in the  calculation.
      If the results for the two initials are
      significantly different you have
      problems -- IDOD.  technique or

B  Undiluted sample BOD  may be determined
   on samples in which the BODj. is less than
   about 8 mg/1.  This limit may be extended
   3 to 5 times if you reoxygenate the  sample
   during the five day incubation or oxygenate
   the sample with oxygen gas  instead of air.
   Extending the range of undiluted sample
   BOD technique is attractive for effluent
   and stream analysis to avoid dilution and
   dilution water problems but generally isn't
   feasible for routine operation.

   1  The undiluted sample procedure

      a   Mix the sample vigorously by shaking
         in a half filled bottle to insure that
         the initial DO is in the range  of 8. 0
         to 8.7 mg/liter.

      b   Siphon the mixture into two or more
         BOD bottles being careful to avoid
         inclusion of air in the sample bottle.

      c   Determine the DO on one bottle.
C  Diluted Sample BOD

   1  Most BOD  data on treatment plant
      influents, in-process samples or
      discharges  employ dilution technique.
      The sample is reduced to some fraction
      in which the oxygenated dilution water
      can supply  more than enough oxygen to
      meet sample requirements during
      incubation.   Dilution technique  com-
      plicates the procedure as a result of
      dilution water addition but the methods
      are similar to those  for undiluted

   2  Dilution technique is feasible on the
      basis of:

      a   Single bottle dilution where the
         measured sample amount is  added
         directly  to each bottle and enough
         dilution  water siphoned into  it to
         fill but not overfill the bottle.

      b   Cylinder dilution technique employs
         a container large  enough to make one
         dilution  of sample and dilution water
         to be used to fill all of the test
         bottles needed. The contents are
         siphoned into the separate bottles
         with care not to change DO during

   3  Before dilutions are  selected it is
      necessary to make some estimate of
      possible BOD  range.  Previous
      experience, COD testing,  or other
      information may be used as a guideline
      for dilution.  In any event,  several
      dilutions  are likely to be necessary to
      obtain one within a usable range of DO
      depletion.  Best results are obtained
      from a DO  depletion  of at least  2 mg/1
      with at least 1 mg/1 remaining  after
      incubation.   Standard Methods * '
      recommends 40 to 70 percent oxygen

BOD Procedures for Treatment Plant Operations
   4 The interrelationship between BOD and
     dilution for BOD, are:
  5-  20 mg/liter
 20- 100 mg/liter
100- 500 mg/liter
500-5000 mg/liter
           use 25 to 100 percent sample
           use 5  to 25 percent sample
           use 1  to 5 percent sample
           use 0.1  to 1 percent  sample
        To calculate dilution from an assumed
        BOD use the same formula for
        calculation of BOD.  That is:
                       (DO  - DO )X100
        BOD, (mg/1) = =	—	^—:	
             5s     % sample used

        If you assumed a BOD of 500 mg/1
        the sample depletion in the middle
        of the acceptable range would be
        4. 0 to 5.0 mg/1 say  4. 5 to be used
        in place of (DO- - DO  )
                      U     D
        % sample =
% sample
4.5 X100
                            or 0. 9%
      c  It would not be advisable to use the
        calculated percent of sample only
        because the sample may be weaker
        or stronger than the assumed value.
        It is preferable to make one smaller
        and one larger dilution—say 0. 5,
        1. 0 and 2 percent sample to cover
        a possible range in BOD, of:

        mg BOD /liter for minimum depletion,
        maximum concentration

        Formula IV. C.4.b.  = 2-°2X1°°

        = 100 mg/1
        for maximum depletion,  minimum
                       7.0X100 _ 700
                          0.5       0.5
concentration =
        = 1400 mg/1
d  Once you have decided upon an
   acceptable dilution range:

   1)  For direct bottle dilution,
      multiply the decimal  fraction
      of the percentage desired by bottle
      capacity to  obtain sample amount
      to be added to each bottle.  For
      a 300 ml bottle and 1 percent
      sample concentration
      300X0.01 = 3 ml sample.
      0. 5 and 2. 0 percent would be
      1.5 and 6 ml respectively.

   2)  For cylinder dilution technique
      you would have to fill a± least
      two bottles, one for initial one
      for final DO titration, hence you
      would need at least 600 ml of
      dilution mix not counting that to
      start, flush the siphon and over-
      run.  Better figure dilution volume
      as 800 ml.   Sample addition
      would be  800 XO. 01 for 1 percent
      sample concentration or 8 ml to
      be filled to the mark (800 ml) with
      dilution water.

e  After dilution  to the mark,  mix the
   sample  carefully.  If you plan on a
   calculated initial do not beat air
   into the sample during mixing.
   With a determined initial you may
   oxygenate by mixing (inversion,
   shaking, plunger action) allow
   entrained air to rise before starting
   the siphon.

f  Fill the intended bottles by flushing
   the siphon to be sure that you have
   swept out air bubbles and previous
   dilutions,  tilt  the BOD bottle  slightly,
   insert siphon tip to the lowest point
   in  the bottle, gradually  open the
   siphon tube to admit diluted sample
   to  fill the bottle.  Stopper without
   inclusion of  air bubbles.

g  Determine the initial DO one  one
   bottle, incubate the other for DO
   determination after 5  days  at 20° c
   + or  - IOC.
                                                                           (DO. - DO,)X100
                                                                              0      5
                                                          mg BOD,/liter =  „,   	—	
                                                           6     5         % sample used

                                             BOD Procedures for Treatment Plant Operations
 D Dilution Water Blanks

   1  It is important that you regularly check
      the quality of the dilution water to be
      used for BOD dilutions.  This water
      should not contain excessive oxidizable
      materials nor should it inhibit oxidation
      of other materials.
B  Carefully identify samples,  dates, time
   on any test container.  Note unusual
   appearance, behavior, etc.  Promptly
   inform operations authority of observations
   likely to affect performance.  Keep your
   records up to date and in consistent
   legible form.  Data is worthless unless
   available when needed.
   2  Many analysts use undiluted BOD
      technique determine initials and
      on unseeded dilution water. In this
      case, air seeding is expected to provide
      the necessary organisms.   Others add
      one drop or more of a well stabilized
      receiving water to the dilution water

   3  Many analysts use the DO   of the dilution
      water blank in place of the DOn of the
      dilution mix to correct for dilution
      water depletion.  Others use the blank
      as a dilution water quality check, with
      or without correction.

   4  This author makes no recommendations
      other than that in III. A. 2.   It  is necessary
      for you to consult your local or State
      authorities for recommended  practice.

 E Seeding, like dilution water, corrections
   are questionable.  A seed depletion deter-
   mined on an undiluted high quality water
   may be quite different from the decimal
   fraction of that depletion in another water
   and another sample.

 A Many procedures are available for BOD
   technique in addition to those considered
   here.  For example, Standard Methods and
   this outline include sfullbottle technique,
   DO measurement,  no agitation during
   incubation.  The Hach apparatus employs
   partially filled bottles, with agitation and
   a pressure measurement.  These and
   others may be used effectively if used
   consistently,  carefully, and the  methods
   are known by those  who interpret them.
   Many options are possible each having an
   affect upon results. Stick to the preferred
   method in your area.  You may have a
   better option but you have to prove it to
   them before acceptance.
C  The Azide Modification of the Winkle r
   titration has a long record in BOD
   technique.  A DO probe has many advantages
   in BOD technique once the analyst knows
   how to use it.  It will require much less
   time for determination of BOD, there is
   no preprepa ration of samples, the sample
   is not destroyed and it requires fewer
   bottles and space.  The probe and Winkler
   method have about the same degree of
   precision on tap water samples.  In plant
   samples the probe may be used effectively
   on many samples where titration is not

D  Do not use large volumes of air by diffusor
   technique to oxygenate dilution water.
   You will tend to concentrate air impurities
   in the clean water. You may filter dust
   from the air; you are not likely to remove
   chlorine, ammonia, organic gases and
   possibly oils in the same manner.  Con-
   tamination may add BOD  or interfere
   with biological  stabilization. Air at room
   temperature contains more than 200 mg
   of oxygen per liter. This is ample to
   saturate several liters of water with DO.
   Storage for two to three days without
   agitation or mixing rapidly by inversion
   or shaking for ten to thirty seconds will
   transfer oxygen from the gas to the liquid
   without undue water contamination.

E  It is not advisable to use BOD initials
   (DO ) higher than about 8. 7 mg/1.  This
   is about 95 percent of DO saturation at
   20° C.  If the temperature  rises during
   or after incubation some of the DO may
   be lost because of supersaturation to
   confuse BOD. results.

F  BOD  samples  to be incubated should be
   adjusted before filling bottles to a tem-
   perature range  from  18.5 to 21.5°C.
   Warmer samples are particularly dangerous
   as the liquid contracts on cooling.  If the

BOD Prodecures for Treatment Plant Operations
   water seal isn't adequate, air will be
   drawn into the bottle.

This outline contains certain information
from previous outlines by D. G. Ballinger,
R.C.  Kroner, and J.M. Mandia.
   FWPCA (Now FWQA) Methods for
      Chemical Analysis of Water and
      and Wastes, Analytical Quality Control
      Laboratory.   November 1969.

   MOP 18 Simplified Laboratory Procedures
      for Wastewater Examination.   WPCF.

1  Standard Methods for the Examination of
      Water and Wastewater,  APHA, AWWA,
      WPCF,  12th Ed.  p. 415.  1965.

2  ASTM Standards Part 23, Water and
      Atmospheric Analysis, pp. 727-732.
This outline was prepared by F. J.  Ludzack,
Chemist, National Training Center,
Federal Water Quality Administration,
Cincinnati, OH  45226.

   The common equation yt =  L (1 - 10 '") for
   BOD relationship indicates time as a
   variable.  The rate coefficient (kj)indicates
   that a specific percentage of material
   initially present (oxygen) will be used
   during a given time unit.  Each successive
   unit of time has less reactant present
   initially than the preceding interval,  hence
   a definite precentage decrease results in
   successively smaller amounts of reactant
   use per unit of lapsed time.  Increasing
   kj results in a larger percentage oxygen
   use per unit of time and also increases the
   change in reactant mass among successive
   time intervals.

B  Adney's work for the British Royal Com-
   mission cited 5 days passage time from
   source to the ocean as maximum for
   English streams.  The 8th Report (1909)
   largely established BOD philosophy in-
   cluding the 5-day interval.  At 5 days,
   initial lags generally have  terminated and
   a substantial fraction of the long-term
   oxygen demand has been exerted.  If only
   one time interval can be used,  7 days
   permits better  scheduling.   Any one time
   interval is "a"  fraction of the  total oxygen
   requirement; this is a poor reference
   point if we do not know  how it arrived. -
   For example, the percentage  of
   oxidizable material stabilized in terms
   of oxygen use at various rate factors
                 % oxidized
                  in 5 -days
o. bs
0. 10
0. 15
0. 50
Kjdog )
0. 11   e
0. 34
1. 15
   This range (K  = 2.3 k  ) is commonly en-
   countered in wastewater stabilization with
   the higher rates characteristic of fresh oxi-
   dizable material that is readily converted.
   The lower coefficients are characteristic
   of cell mass at later stages of oxidation
   and of low-rate reactants  in general.

C  The oxygen utilization at  specified inter-
   vals of time are required to estimate k.,
   and L, the estimate of oxygen use at
   infinite time.   It is common to observe
   results at equal intervals of time but
   this is not  essential as long as
   the time  intervals are accurately known.
   The initial time periods are critical as
   an error of a few hours in time  represents
   a relatively large change  in reactant mass
   in a system at  maximum  instability.  Un-
   equal time periods can be plotted to define
   the curve from which any given  intervals
   can be selected as desired.
D  Increasing impoundment of surface water
   provides more time for stabilization of
   relatively inert soluble or suspended
   pollutants and for organism adaptation
   to the situation or pollutants.  Long term
   BOD's are essential to indicate changes
   in the pattern of oxygen demand'vs. time.
   It may be expected that one or more
   plateaus will be evident in the BOD curve
   followed by a temporary rise in rate
   during second stage oxidation or thereafter.
   Anaerobiosis may cause a rise in rate
   coefficient after aerobic conditions are
   re-established.  Eventually k stabilizes
   at very low values.

   1  Rate coefficients tend to be difficult to
     interpret  during long term BOD's
     because of progressive changes and
     other factors.

     a  The relative error of the DO test may
        be a large  fraction of the incremental
        DO change during low rate periods.

     b  Cell mass  may agglomerate under
        quiescent test conditions and decrease
        nutrient availability.

 Effect of Some Variables on the BOD Test
      c It is not likely that recycled nutrients
        under aerobic test conditions will
        have as much effect as recycle from
        anaerobic benthic deposits in a

   2  The BOD result tends to underestimate
      deoxygenation relative to surface water
      behavior because  of interchanges,
      turbulence, biota,  and boundary effects.
      Reseeding does not occur in a sealed
      bottle but reseeding is inevitable in a
      stream or treatment unit.


 A Effect on Oxidation Rate

   Temperature is one  of the important con-
   trolling  factors in any biological system.
   In the BOD reaction, changes in tempera-
   ture produce acceleration or depression
   of the rate of oxidation.  Figure 1 shows
   the changes in the value of k at tempera-
   tures from 0 - 25°C  on a common
B  Test Temperature

   In the BOD test procedure an arbitrary
   temperature is usually selected for
   convenience even though a wide temperature
   range exists under natural conditions.

   Incubation of the test containers at 20°C
   for the whole period is now accepted
   practice in the  U.S.; 18. 5°C is preferred
   in England.  Camp (ASCE,  SA591:1,  Oct.
   65) recommended light and dark bottle
   immersion in the stream.

C  Temperature Correction

   When it is necessary to calculate the rate
   of oxidation at a temperature other than
   20°, the following relationship may be
                       DEGREES C.
            =   e
                    - T2)
      k1 =  rate coefficient at  temperature T^

      k  = rate at-coefficient at  temperature T0
       Z                                    &

       8 = temperature coefficient, for which
           Streeter and Phelps  obtained the value
           1. 047.  6 changes with temperature; it
           appears to be higher in  the range of
           5-15°C than in the range of 30 to 40°C.
           The value given refers to 15-30°.
     The cited temperature coefficient appears
     reasonable for household wastes.  It may
     not apply for other wastes where developing
     or seed organisms may not tolerate tem-
     perature changes as readily.  A given
     temperature  coefficient should be checked
     for applicability under specified conditions.
 Ill  pH

  A The organisms involved in biochemical
     conversions apparently have an optimum
     response near a pH of 7.0 providing other
     environmental factors are favorable; a pH
     range of about 6.5 to 8. 3 apparently is
     acceptable (Figure 2).  Reactivity is likely
     to be significantly lower on both sides of the
     acceptable pH range but microbial adapta-
     tion may extend the limits appreciably.
     For example,  trickling filters have operated
     with better than 50% treatment efficiency
     at pH 3 and 10 after adaptation.

                                                   Effect of Some Variables on the BOD Test
           4        6    pH    8        10
 B Adjustment of Concentrated Samples

    When wastes are more acid than pH 6. 5 or
    more alkaline than pH 8. 3,  adjustment to
    pH 7.2 is advisable before reliable BOD
    values can be obtained.

 C Dilution Samples
    Standard dilution water is buffered at pH
    7.2.  Sample-dilution water mixtures should
    be checked to make sure that the sample
    buffer capacity does not exceed the capacity
    of the dilution water for pH adjustment.


 A Importance
    In 1932 Butterfield reported on the role of
    certain minerals in the biochemical oxidation
    of sewage and concluded that deficient
    minerals often upset  metabolic response.
    In addition, he found  that inadequate nitrogen
    and/or phosphorus was a common cause of
    low BOD results in industrial wastewaters.
    (Figure 3)
               Effect of Mineral Nutrients on BOD
 B Standard Methods Dilution Water

   The dilution water specified for the BOD
   test approximates USGS estimates for an
   average U. S.  mineral content of surface
   water except for added phosphate buffer.
   It is assumed to provide essential mineral
   nutrients  for most wastewaters but  cannot
   be expected to meet requirements for
   grossly deficient wastewater nutrients both
   mineral and organic.  Ruchhoft (S.W. J.
   13:669, 1941)  summarized committee action
   leading to the present dilution water.

 C Other Dilution Considerations

   There is a trend toward the use of receiving
   water,  storage-stabilized if necessary,  to
   evaluate waste behavior.  It is advisable
   to minimize dilution and consider the
   nutrient level likely in the receiving water
   as most valid.  Any change in the environ-
   ment,  such as dilution, upsets the
   microbial balance and requires adaptive


 A Need for Complex Flora and Fauna

   Butterfield, Purdy,  and Theriault (Pub.
   Health Rep. 393,  1931) demonstrated that
   an isolated species of organisms was not
   as effective in biological stabilization as
   a  variety of species.   Figure 4  summarizes
   some of their data.  Bhatta and Gaudy
   (ASCE, SA3,  91:63, June 1965) reinvestigated
   this factor.  Many studies have emphasized
   the need for a mixed  biota in the BOD test.
   It appears that bacteria are capable of
   varied activities,  but all species are not
   capable of synthesizing all required nutrients.
   Certain bacterial species may be capable
   of producing enzymes,  amino acids, or
   growth factors needed for their use and  by
   other species for optimum performance.
   It has been shown that oxygen demand
   becomes minimal when some limit of
   bacterial population has been reached.
   Predation prevents such an approach to
   maximum numbers and maintains a con-
   tinuing bacterial growth and recycle of
   nutrients  among a mixed population. The
   net effect is a symbiotic, relation among
   mixed organisms  tending to enhance the
   rate of stabilization or utilization of
   oxygen as in the BOD test.

Effect of Some Variables on the BOD Test
B  Organism Adaptation

   1 Early investigations in relation to the
     BOD test considered domestic wastewaters
     primarily.  The saprophytic organisms
     involved in stabilization either were
     present in adequate numbers or quickly
     multiplied to attain effective populations.

   2 The period of adjustment required to
     shift enzyme production needed to utilize
     an energy source different from that
     previously utilized or to shift population
     variety from that favored by one food to
     that favored by another food is con-
     sidered an adaptation period. Dilution,
     temperature,  oxygen tension, pH,
     nutrient type, inhibitory substances,
     light and other changes all are common
     inducements for microbial adaptation.
     Mutation of organisms may be encountered
     during adaptation but usually is not a

   3 The developments in industry and
     technology have resulted in discharge
     of new and more varied wastewater
     constituents.  Microorganisms may
     adapt themselves to the use of a new
     substance as an energy source providing
     the energy and environment are favor-
     able.   The receiving stream usually shows
     development of an adapted  microbiota
     for a new or different discharge con-
     stituent within hours, days or weeks
     after fairly regular discharge.  The
     time for adaptation depends on the nature
     of the constituent, available energy,
     tolerance of the organisms,  and environ-
     mental conditions.

C  Seeding

   The amount of seed and its selection must
   be determined experimentally. The most
   effective inoculant would be that which
   would produce the maximum BOD response
   with minimum lag period and negligible
   seed demand.  This would mean some
   maximum population adapted  to feed and
   conditions at a minimum equilibrium energy
   nutrient supply.
1 Figure 5 indicates corrected BOD
  progression on a synthetic feed with
  river water and stale sewage inoculants
  at several concentrations.  The river
  water resulted in higher BOD with
  negligible lag and seed correction.  The
  seed correction at 20% concentration
  of inoculant was less than 0.3 mg.
  DO/1 at 5 days.  It would be possible to
  use this  river water as a diluent without
  excessive oxygen loss to produce more
  valid BOD progression for that receiving
  water.  The lower wastewater inoculant
  concentration resulted in a  definite BOD
  lag.  Higher wastewater concentrations
  produced comparable BOD progression
  earlier but resulted in high seed
  corrections and lowered availability of
  dissolved oxygen for the sample.

2 A  good secondary treated effluent
  produced results similar to river water
  inoculation with higher seed corrections
  per increment of applied inoculant.
  Soil suspensions also are very effective
  sources  of seed organisms  with minor
  seed corrections if they are reasonably
  stabilized surface soils.

3 It  appears that the BOD progression
  most nearly indicating receiving water
  oxidation would be one based upon
  receiving water dilution or  inoculated
  with organisms from it.

4 A  new or unusual wastewater may
  require adapted organisms  not present
  in sufficient numbers in the receiving
  water.  Development of an  adapted seed
  from soil suspensions, plant effluents
  or receiving water may be  necessary to
  evaluate oxidation potential in a plant
  or receiving water at some future time.
  Enrichment culture  technique is bene-
  ficial where small concentrations of the
  test wastewater are applied regularly
  with increases in wastewater concen-
  trations  as BOD or respiration activity
  indicates increasing tolerance and
  oxidation of the test waste.  Both time
  and concentration limits are useful to
  characterize the wastewater and its
  acceptability for biological stabilization.

                                                   Effect of Some Variables on the BOD Test
                  AH forms in nvpr water
                  Mixed Bacteria A plankton
                  Pure culture B. Aerogened 
Effect of Some Variables on the BOD Test


  Q 80
                  Table I
                    2       3
                  Time in Days
        Effect of Cyanide on BOD of Domestic Sewage
          (2% Sewage in Formula C Dilution Water)

                Figure 6

   Heavy metals have similar effects depending
   on history and environment. The effects of
   copper and chromium  are  illustrated in
   Figure 7.
        ,0  .1  ,2  .3   .J   5  .6  .'


                 Figure 7
B Detection
   In laboratory determinations of BOD the
   absence of toxic substances including
   chlorine must be established before the
   results can be accepted as valid.
   Comparison of BOD values for several
   dilutions of the waste will indicate the
   presence or absence of toxicity.  In Table 1
   the calculated BOD for the dilutions show
   higher values in the more dilute concen-
   trations.  It is apparent that toxicity was
   present and that the toxic effect  was diluted
   out at a waste concentration of 2% or less.
5 day BOD

 A Mechanism

    The oxidation process, as exemplified by
    the equation:
                                                            y = L(l-I0"kt)
                                                      presumably involves the oxidation of
                                                      carbonaceous  matter or 1st stage oxygen
                                                            C H O
    The  rate coefficient is normally high,  giving
    nearly complete oxidation in a few days.
    When nitrogenous material is present its
    oxidation can be shown as:
                                                                         - °2
                                                            NH3 -
     Nitrogen oxidation may be delayed for
     several days during BOD tests unless
     suitable micro-biota are initially available.
     Under some circirfhstances these two
     oxidations can proceed simultaneously and
     the resultant BOD curve will be a com-
     posite of the two reactions.
    = | Lc
                                                  Effect of Some Variables on the BOD Test
L  and L  = the ultimate oxygen demands
characteristic of the two phases respectively.
This is the general formula for any system
characterized by two simultaneous reactions.

Principal conditions governing simultaneous
carbon and nitrogen oxidation:

1  Presence of an effective nitrifying
   culture at the beginning of the test
   interval (nitrifiers grow relatively

2  Maintenance of adequate DO, believed
   to be a minimum of 0. 5 to 1.0 mg/1,
   for nitrifier activity.

3  Available nitrogen - in excess of that
   required for synthesis.  This is believed
   to require a minimum of about 7 mg/1
   to support active nitrification on a
   continuous basis.

4  Nitrifiers appear to be more sensitive
   to toxicity than most saprophytic
   organisms,  hence are likely to be
   inhibited more  readily.  This is
   particularly evident during nitrite to
   nitrate conversion.

It  may require 5 to 10 days to establish
nitrification if the population was not
nitrifying initially.  This is  the basis for
the sequential carbonaceous and nitrogenous
oxidation of sewage oxidation.

1  Effects on the BOD curve indicate a
   typical pattern  such as in Figure 8.
   The influence of nitrification in the
   production of a  secondary rise in the
   BOD curve is so well known that  any
   secondary rise  may be erroneously
   attributed to nitrification  whether  or
   not nitrification was involved.  Actually,
   a secondary rise in the curve may be
   due to any oxidation system assuming
   dominance after the initial oxidation
   system has been completed.

2  The nitrification phenomena occurs
   simultaneously  in many streams,
   treated effluents or partially stabilized
   samples.  The  designation of a secondary
     BOD rise to nitrification should be
     based on analysis, not curve shape.

C  The extent of nitrification is conclusively
   shown  only by periodic analysis of
   ammonia, organic, nitrite and nitrate
   nitrogen.  The conversion of ammonia
   and organic  nitrogen to oxidized nitrogen
   is a definite indication of nitrification.

D  Nitrification Inhibition

   Plant efficiencies from a BOD standpoint
   can be  erroneous because nitrification
   generally  is not established  during the
   usual incubation of influent samples but
   may be a major factor in effluent
   incubations.  It requires about 2 times
   the  oxygen to convert NH_ -N to NO_  -N
   as to convert C to CO   hence this is a
   major  fraction of stream oxygen use.
   Most secondary treated effluents are
   characterized by a larger fraction of
   carbon than  nitrogen removal which
   accentuates  the problem.

   Pasteurization of samples,  methylene
   blue, chromium, and acid treatment
   followed by neutralization have been used
   to inhibit nitrification for estimation of
   carbonaceous  BOD only.  Any inhibition
   of nitrification also produces a change in
   the  sample  or its behavior  and may
   partially inhibit carbonaceous oxidation.
   Nitrification is a factor in stream self-
   purification  and treatment.   It does not
   appear realistic to alter it for convenience.
   The most  realistic approach to carbon-
   aceous oxidation is the measurement of
   CO   or COD.
                                                                      TIME IN DAT1
                                                                    OF NITRIFICATION OM B 0 D
                                                                  Figure 8

 Effect of Some Variables on the BOD Test

When a series of dilutions are made on a
BOD sample usually the result s vary to the
extent that only an approximate BOD value
is obtained.

                 Table 2

Sample cone.

2. 7
4. 9

A  For example,  in Table 2, 1%, 2% and 4%
   concentrations of sample were used.  The
   4% concentration became anaerobic before
   the end of 5 days.  The 5-day BOD of the
   1% concentration was 270 and that of  the
   2% concentration was 245.

B  Statistically one value is more reliable
   than the other.


 ^ depletion

5.5 mg/1

3.3 mg/1
2.2 mg/1
   The difference in depletion between 1 and
   2% dilutions is 2.2 mg/1.  This  difference
   may be attributed to an additional 1% of
   sample added to the  original 1%.  If the
   difference is multiplied by the dilution
   factor of 100 to obtain the BOD, the result
   is 220 mg/1.

     1  We now have three estimates of the
        BOD on a one percent concentration
        basis from the  two dilutions:

        a the actual 1% depletion gives 270
        b 2%/2 depletion gives 245
        c (2%- 1%) depletion gives 220
Statistically the probabilities of being
nearer the actual value goes with the
nearest two of three.  The 4% value
of 8.2 depletion/4 as a minimum
possible BOD 1% concentration gives
a BOD of at least 200.

There is the possibility that higher
concentrations may reflect  significant
toxicity while lower concentrations
tend to reflect a greater proportion of
dilution water.  The toxicity problem
does not appear to be significant since
the 4% sample concentration indicated
a BOD of at least 200.  The higher
BOD at  1% sample concentration may
be due to a contaminated dilution water
or to the fact that a similar number of
seed organisms had less food and
utilized certain fractions that they  had
passed by when they had more choice
with the  2% sample concentration.
Data is  insufficient to resolve this  one.

Incubations having a depletion of at
least 2 mg DO/liter and a residual of
at least 1 mg DO/liter are indicated
to be most valid' '.   Both the 1  and
2% concentrations fit this requirement
in Table 2.  An average error of
+ or -0.1 ml on the DO titration would
have a smaller relative error upon
the 2% depletion.

We have a reasonable presumption
that the sample BOD of about 230 was
a good estimate. We do not have an
unequivocal basis for so stating.
Possible variations in results with
different dilutions of a given sample
are subject to many uncertainties in
the test routine.

If some cause is known -  such as a
titration eror,  the inclusion of ex-
traneous substances producing high
or low response, or a definite procedural
error that rules out a valid estimate of
the sample BOD- that result should be
labeled as a lost cause or unreported.
Otherwise,  report what was obtained
to the best of your ability with the
provision of uncertainty for uncon-
trollable s.

                                                   Effect of Some Variables on the BOD Test

Certain portions of this outline contain
training material from prior outlines by
D. G,  Ballinger and J. W. Mandia.

Standard Methods, APHA-AWWA-WPCF,
  13thjjdition, J.971.	
This outline was prepared by F.  J.  Ludzack,
Chemist,  National Training Center, DTTB,
MDS, OWP,  EPA, Cincinnati, OH  45268.

A  The Chemical Oxygen Demand (COD) is
   an estimate of the proportion of the sample
   matter susceptible to oxidation by a
   strong chemical oxidant.  The current
   edition of Standard Methods,    specifies.
   organic material which is generally the
   situation but not necessarily applicable.
   A variety of terms have been and are used
   for the test described here as COD:

   1 Oxygen absorbed (OA) primarily in
     British practice.

   2 Oxygen consumed (OC) preferred by
     some, but unpopular.

   3 Chemical oxygen demand (COD) current

   4 Complete oxygen demand (COD)

   5 Dichromate oxygen demand (DOC)
     earlier distinction of the current pre-
     ference for COD by dichromate or a
     specified analysis such as Standard

   6 Others have been and are being used.
     Since 1960, terms have  been generally
     agreed upon within most professional
     groups as indicated in I-A and B-3 and
     the explanation in B-5.

   The concept of the COD is almost as old
   as the BOD.  Many oxidants and varia-
   tions in procedure have been proposed,
   but none have been completely

   1 Ceric sulfate has been investigated,
     but in general it is not a strong
   Potassium permanganate was one of
   the earliest oxidants proposed and
   until recently appeared in Standard
   Methods (9th ed.) as a standard pro-
   cedure. It is currently used in
   British practice as a 4-hr, test at
   room temperature.

   a The results obtained with perman-
     ganate  were dependent upon  concen-
     tration  of reagent,  time of oxidation,
     temperature, etc., so that results
     were not reproducible.

   Potassium iodate or iodic acid  is an
   excellent oxidant but methods employing
   this reaction are time-consuming and
   require a  very close control.

   A number  of investigators have used
   potassium dichromate under a  variety
   of conditions.   The method proposed
   by Moore  at SEC is the basis of the
   standard procedure. (*• 2' Statistical
   comparisons with  other methods are
   described. '3'
5  Effective determination of elemental
   carbon in wastewater was sought by
   Buswell as a water quality criteria.

   a Van Slyke* ' described a carbon
     determination based on anhydrous
     samples and mixed oxidizing agents
     including sulfuric, chromic, iodic
     and phosphoric acids to obtain a
     yield comparable  to the theoretical
     on  a wide spectrum of components.

   b Van Hall, et al., ^ used a heated
     combustion tube with infrared
     detection to determine carbon quickly
     and effectively by wet sample

6  Current development shows a trend to
   instrumental methods automating
 CH. O. oc. 10e.12.71

 Chemical Oxygen Demand and COD/BOD Relationships
      conventional procedures or to seek
      elemental or more specific group
 A  Table 1
Van Slyke
Carbon detn.
Carbon by
Temp. °C
2 hrs.
1 hr.
20 min.
Biol. prod.
Enz. Oxidn.
50% H2SO4
May be cata-
Diss. oxyg.
Oxygen atm.
HOC1 soln.
Compound, environ-
ment, biota, time,
numbers. Metabolic
acceptability, etc.
Susceptibility of
the test sample to
the specified
Includes materials
rapidly oxidized by
direct action,
Fe . SH.
Excellent approach
to theoretical oxi-
dation for most
compounds (N-hil)
Comparable to
theoretical for
carbon only.
Good NH3 oxidn.
Variable for other
 B From Table 1 it is apparent that oxidation
   is the only common item of this series of
   separate tests.

   1  Any  relationships among COD & BOD
      or any other tests are fortuitous be-
      cause the conditions of test tend to give
      results indicating the susceptibility of
                                                    a given sample to oxidation under
                                                    specified conditions that are different
                                                    for each test.

                                                    If the sample is primarily composed
                                                    of compounds that are oxidized by
                                                    both procedures (BOD and COD) a
                                                    relationship may be established.

                                         Chemical Oxygen Demand and (TOD/BOD Relationships
       a  The COD procedure may be sub-
          stituted (with proper qualifications)
          for BOD or the COD may be used
          as an indication of the dilution
          required for setting up BOD

       b  If the sample is characterized by a
          predominance of material that can
          be chemically, but not biochemi-
          cally oxidized, the COD will be
          greater than the BOD. Textile
          wastes, paper mill wastes,  and
          other wastes containing high con-
          centrations of cellulose have a
          high COD, low BOD.

       c  If the situation in item b is reversed
          the BOD will be higher than the
          COD.  Distillery wastes or refinery
          wastes may have a high BOD,  low
          COD,  unless catalyzed by silver

       d  Any relationship established as in
          2a will change in response to
          sample history and environment.
          The BOD tends to decrease more
          rapidly than the COD.  Biological
          cell mass or detritus produced by
          biological action has a low BOD
          but a relatively high COD.  The
          COD/BOD ratio tends to increase
          with time, treatment,  or conditions
          favoring stabilization.

 A Advantages

    1  Time,  manipulation, and equipment
       costs are lower for the COD test.

    2  COD oxidation conditions are effective
       for a wider spectrum of chemical

    3  COD test conditions can be standardized
       more readily to give more precise
       COD results are available while the
       waste is in the plant, not several
       days later, hence, plant control is

       COD results are useful to indicate
       downstream damage potential in the
       form of sludge deposition.

       The COD result plus the oxygen equiva-
       lent for ammonia and organic nitrogen
       is a good estimate of the  ultimate BOD
       for many municipal wastewaters.
  B  Limitations
       Results are not applicable for estimating
       BOD except as a result of experimental
       evidence by both methods on a given
       sample type.

       Certain compounds are not susceptible
       to oxidation under COD conditions or
       are too volatile to remain in the oxida-
       tion flask long enough to be oxidized.

       Ammonia, aromatic hydrocarbons,
       saturated hydrocarbons,  pyridine, and
       toluene are examples of materials with
       a low analytical response in  the COD

       Dichromate in hot 50% sulfuric acid
       requires close control to maintain
       safety during manipulation.

       Oxidation of chloride to chlorine is not
       closely related to BOD but may  affect
       COD results.

       It is  not advisable to expect precise
       COD results on saline water.

The  COD procedure    considered dichro-
mate oxidation in 33 and 50 percent sul-
furic acid.  Results indicated preference
of the 50 percent acid concentration for
oxidation of sample components.  This is
the basis for the present standard

Chemical Oxygen Demand and COD/BOD Relationships
 B  Muers^ ' suggested addition of silver
    sulfate to catalyze  oxidation of certain
    low molecular weight aliphatic acids and
    alcohols.  The catalyst also improves
    oxidation of most other organic components
    to some extent but  does not make the COD
    test universally applicable for all chemical

 C  The unmodified COD test result (A) includes
    oxidation of chloride to chlorine.  Each mg
    of chloride will have a COD equivalent of
    0. 23 mg.  Chlorides must be determined
    in the  sample and the  COD  result corrected

    1  For example,  if a sample shows 300
      mg of COD per liter and  200 mg Cl"
      per  liter the corrected COD result will
      be 300 -(200 x 0.23)or 300 -  46 = 254
      mg COD 11 oh a chloride corrected iasis.

    2  Silver sulfate addition as a catalyst
      tends to cause partial precipitation of
      silver chloride even in the hot acid-solu-
      tion. Chloride corrections are ques-
      tionable unless the  chloride is oxidized
      before addition of silver  sulfate,  i. e.,
      reflux for 15 minutes for chloride ox-
      idation, add Ag  SO ,  and continue the
      reflux or use of HgSO4(D).

 D Dobbs and Williams x ' proposed prior
    complexation of chlorides with HgSO4 to
    prevent chloride oxidation during the test.
    A ratio of about 10 of Hg + to 1 of Cl~ (wt.
    basis) appears essential.  The Cl~ must
    be complexed in acid solution before addi-
    tion of dichromate and silver sulfate.

    1 For unexplained reasons the HgSO4
       complexation does  not completely
      prevent chloride oxidation in the
      presence of high chloride concentrations.

    2  Factors have been developed to provide
       some estimate of error  in the result
       due to incomplete control of chloride
       behavior.  These tend to vary with the
       sample and technique  employed.

  E It is not likely that COD results will be
    precise for samples  containing high
    chlorides.  Sea water contains 18000 to
    21000 mgCl"/I normally.  Equivalent
    chloride correction for COD exceeds
   4000 mg/1.  The error in chloride
   determination may give negative COD
   results upon application of the correction.
  Incomplete control of chloride oxidation
  with HgSO4 may give equally confusing
            appears to give precise results
     for COD when chlorides do not exceed
     about 2000 mg/1.  Interference in-
     creases with increasing chlorides at
     higher levels.

F The 12th edition of Standard Methods re-
  duced the amount of sample and reagents
  to 40% of amounts utilized in previous
  editions.  There has been no change in
  the relative proportions in the test.  This
  step was taken to reduce the cost of pro-
  viding expensive mercury and  silver sul-
  fates required.   Results are comparable
  as long as the proportions are identical.
  Smaller aliquots of sample and reagents
   require more care during manipulation
   to promote precision.

G  The  EPA Methods for COD

   1  For routine level COD (samples having
      an organic  carbon concentration
      greater than 15 mg/liter and a chloride
      concentration less than 2000  mg/liter),
      the EPA  specifies the procedures found
      in Standard Methods (?)and in ASTM(8).

   2  For low level COD (samples  with less
      than 15 mg/liter organic carbon and
      chloride  concentration less than 2000
      mg/liter),  EPA provides an analytical
      procedure ^). The  difference from
      the routine procedure primarily in-
      volves a greater sample volume and
      more dilute solutions of dichromate
      and ferrous ammonium sulfate.

   3  For saline samples (chloride level
      exceeds  1000 mg/liter and COD is
      greater than 250 mg/liter), EPA
      provides an analytical procedure^  '
      involving preparation of a  standard
      curve of COD versus mg/liter
      chloride to correct the calculations.
      Volumes and concentrations  for the
      sample and reagents are adjusted for
      this type of determination.

                                      Chemical Oxygen Demand and COD/BOD Relationships
V  The precision of the unmodified COD
 result shows a standard deviation of + 4%of the
 mean '^'on low chloride samples. Silver
 sulfate modified COD results are likely to
 show a standard deviation about twice that
 without catalysis, due  to questionable
 chloride behavior.  The determination of
 chloride frequently  shows a coefficient of
 variation (s/x) of 10 to 157c, hence high
 chloride samples result in COD precision
 controlled more by  chloride behavior than
 organic oxidation.


 A  Sample size and COD limits for 0.25  N
    reagents are approximately as given.
    For 0. 025 N reagents multiply COD by
    0.1.  Use the weak reagents for COD's
    in the range of 5-50 mg/1, (low level).
     Sample Size

        20 ml
        10 ml
         5 ml
                       mg COD/1

Most organic materials oxidize relatively
rapidly under COD test conditions.  A
significant fraction of oxidation occurs
during the heating upon addition of acid.
The color change of dichromate after
acid addition indicates the approximate
fraction of dichromate remaining.  If
the mixed sample color changes from
yellow to green after acid addition the
sample was too large.   Discard without
reflux and repeat with  a smaller
aliquot until the  color after mixing  does
not go beyond a brownish hue.  The
dichromate color change is less rapid
with sample components that are slowly
oxidized under COD reaction conditions.

Chloride concentrations should be known
for all test samples and results inter-
preted accordingly.

Special precautions advisable for the
regular COD procedure and essential
when  using 0. 025 N reagents include:

1  Keep the apparatus assembled  when
   not in use.

2  Plug the condenser breather tube with
   glass wool to  minimize dust entrance.
                                                  Wipe the upper part of the flask and
                                                  lower part of the condenser with a
                                                  wet towel before disassembly to
                                                  minimize sample contamination.
                                                   Steam out the condenser after use for
                                                  high concentration samples and periodi-
                                                  cally for regular samples.  Use the
                                                  regular blank reagent mix and heat,
                                                  without use  of condenser water, to
                                                  clean the apparatus of residual oxidiz-
                                                  able components.

                                                   Distilled water and sulfuric acid must
                                                  be of very high quality to maintain low
                                                  blanks on the refluxed samples for the
                                                  0. 025 N oxidant,

Certain portions of this outline contain
training material from prior outlines by
R. C. Kroner, R.  J.  Lishka, and J. W.  Mandia.

                                                 1 Moore, W. A., Kroner,  R. C. and Ruchhoft,
                                                       C.C.  Anal. Chem. 21:953 1949.
                                                 2  Standard Methods.  13th Edition. APHA-
                                                       AWWA-WPCF, 1971.

                                                 3  Moore,  W. A.,  Ludzack, F.J. and
                                                       Ruchhoft. C.C.  Anal. Chem. 23:1297,

                                                 4  Van Slyke, D. D.  and Folch, J.J.  Biol.
                                                       Chem. 136:509 1940.

                                                 5  Van Hall, C.E.,  Safranko, J. and Stenger,
                                                       V.A., Anal.  Chem.  35:315  1963.

                                                 6  Muers,  M. M.  J. Soc.  Chem.  Ind. (London)
                                                       55:711 1936.

                                                 7  Dobbs,  R.A. and Williams, R.T.,   Anal.
                                                       Chem. 35:1064 1963
                                                  8 ASTM Standards, Part 23, Water:
                                                       Atmospheric Analysis, 1970.

                                                  9 Methods for Chemical Analysis of
                                                       Water and Wastes,  EPA-AQCL.
                                                       Cincinnati, OH,  July 1971.
                                                           See Next Page.

Chemical Oxygen Demand and COD/BOD Relationships
                                                This outline was prepared by F. J. .Ludzack,
                                                Chemist, National Training Center, MDS,
                                                OWP, EPA, Cincinnati, OH  45268.

                                      PUMP MAINTENANCE

  A Pumping is a fact of life in wastewater
     treatment plant operation.  You probably
     have sewage pumps, air pumps, sludge
     pumps, proportioning pumps for oil, fuel,
     or chemicals, recirculating pumps for
     gas process waters or sludge.  Some pumps
     are intended for continuous operation,
     some for intermittant operation.  You are
     likely to have many different sizes  and
     several different types of pumps available
     for different purposes.

  B You will have to learn to live with pumps.
     With appropriate lubrication and care of
     them, your life will be easier and much
     more productive.

  A  It is assumed that your plant has been
     checked out for service and is in operation.
     Start up routine is a function of the
     representatives of the  plant facility, the
     consultant, the contractor and the  equipment
     manufacturer, or supplier.  Hopefully,  you
     were a key part of this phase of  operation
     to learn as much as possible from it.

  B  Your plant records should contain  specific
     instructions, drawings and descriptive
     material for each pump in service.
     Assemble and file them in an orderly
     fashion so that you can locate them when
     you need them.

  C  Each pump should have a record card
     including make, model serial number and
     date of installation; name of the  supplier
     or service representative,  and lubrication
     instructions. This card should be posted
     preferably in a suitable place in the pump
     vicinity so that a running record on it can
     be maintained.  Date of lubrication, cleanup,
     notes on operating problems, and initials
     of the individual making the entry are
     regularly sought. As soon as one card is
     filled, permanently file it and replace it
     with a new record card.

  Pump bearings are one of the major sources
  of trouble.  Daily observations are necessary
  to avert trouble.
A  Any irregularity in noise vibration
   temperature or flow is an. indication of
   trouble and should be  closely watched.
   This is applicable not only to pumps but
   to pump drivers as well.

B  Lets assume that you  are starting a new
   pump or restarting one that has received
   a cleanout or overhaul.  Check for proper
   greasing,  pump rotation and alignment.

   1  Check bearing temperature for the first
      hour of operation or until they reach a
      stable running temperature under
      conditions of use.   Be sure that an
      appro-ved bearing temperature device
      is used - hand contact may be handy
      but it is not advisable because a  "cooked"
      hand is not very useful for you or for the
      record.  If the temperature does not
      stabilize within a reasonable running
      range find out why  before serious
      difficulty develops.

   2  If the temperature  stabilizes in an
      acceptable range,  you probably are in
      business for 1000 to 2000 hours of
      operation depending upon severity of
      service such as dampness,  corrosivity,
      abrasives, etc.

   3  Learn to recognize the sound of the unit
      under favorable use conditions.  Air
      leakage into the suction side,  overloads,
      discharge obstructions, loose anchorage
      and many other problems may be
      detected by sound changes.

C  Greasing during service depends on the
   operation and the  equipment.

   1 For 24 hour service, add grease every
      6-12 weeks.  Clean out bearings and
     bearing housings every 12-18 months
     with hot (200-240 F) kerosene flushing.
     Follow with a light  mineral oil flush
      and repack the bearing with the
     recommended grease.

   2 For 8 hr/day service, add grease every
      6-8 months.

   3 For light duty or standby service, run
     pumps for 1 to 2 hours every month to
     prevent rust  accumulation.  Have the
     bearings cleaned an.d flushed (hot
     kerosene 200-240 °F) once yearly and
     repacked with recommended grease to
     SE.TT.eq. 6. 8. 70

Pump Maintenance
      prevent damage due to oxidation of

   4  Grease would normally be a good
      quality No. 2 moisture resistant
      variety for normal temperatures.
      A No.  1 grease is used for higher
      speeds or lower ambient temperatures.
      Where bearing temperatures are up
      to 150°F;  a lime base inhibitor is
      normally used and a lithium base
      generally used where  the bearing
      temperatures are higher than 150°F.
      Check the pump manufacturers'

   5  For bearings equipped with grease
      plugs, remove both takeout plugs and
      do not over fill during repacking.
      Increased temperatures during running
      will expand the grease and cause a
      dangerous pressure rise after replacing
      plugs which is likely to damage the
      bearing.   It may be advisable to run the
      unit for a short time before  reinserting
      the second plug to get rid of excess

   6  A constant level oiler is usual for oil
      lubricated bearings.  A high quality
      turbine or hydraulic oil containing rust,
      oxidation, and foam inhibitors is
      recommended.  Check equipment and
      lubricant manufacturers recommendation.
      Normally a 10-W oil is used for bearing
      temperatures of 125 to 145°F and a 20-W
      oil for bearing temperatures of 145 to
      180°F.  Note - The oiler level must be
      as shown on drawings or bearing housing
      for a  high oil level is  as bad as
      overgreasing a bearing.  A complete
      oil change is recommended every 6 to
      8 months of average operation.  More
      often  if the atmosphere is damp and
      corrosive as it usually is in sewage
      treatment plants.

   Long term storage without operation
   requires special care on either grease or
   oil lube bearings to prevent bearing
   troubles. If a pump is likely to be on
   standby for more than one month:

   1  Request the manufacturer to prepare
      it for long term storage or

   2  Coat shaft and bearings with heavy
      grease to prevent rusting.

   3  Before use, clean by hot flushing as
      described in El. C.I.  and replace
      with the recommended lubricant.
      Almost all initial bearing failures are
      traceable to neglect of storage

 A Pump packing may be carefully done
   either at the factory or by in-house
   replacement. Its service life generally
   depends on careful adjustment and checking
   of conditions to insure that it does prevent
   gross pump leakage without excessive
   heating or wear on the shaft  sleeves.

 B Remember that the packing of any pump
   is cooled  and lubricated by the leakage of
   liquid from the packing or "stuffing box. "

   1  Never  tighten the packing gland so that
      leakage is stopped completely. A steady
      rate of 10-15 drops/minute of leakage
      through the packing is the proper rate.

   2  Never  tighten packing on a unit that is
      not running  .

   3  Start the pump, allow it to leak fairly
      rapidly for a few minutes running.
      Tighten the packing gland evenly  and a
      little at a time allowing it to run for a
      few minutes after each take-up stage.
      (Use hand tightening)

 C Once the packing is old and worn or leakage
   cannot be controlled readily  by packing
   gland adjustment, repack the stuffing box -
   never add one more packing  ring to take
   up the "slack" and give a bit more adjustment.

   1  Remove all old packing, the lantern
      ring and/or seal cage.   Careful - these
      are generally "stuck" in place.  There
      is no easy removal.  Your service
      representative generally can supply
      tips to help you remove packing in your
      particular type of pump without damaging
      the shaft sleeve or housing.

   2  After removal of stuffing, clean the box
      thoroughly.  Inspect the box, shaft  sleeve,
      lantern ring, and/or seal cage.  Make
      certain that the shaft sleeve is not
      unduely worn or damaged.  You will
      waste time and material repacking if
      it is.

   3  Cut the packing about 1/16 inch longer
      than measured -  this will insure that
      the outside diameter of the packing
      ring will hug the  stuffing box rather
      than the shaft sleeve and cause

                                                               JPump Maintenance
      excessive wear.  Use a sharp cutting
      tool to get a clean cut.  The usual
      packing for water and sewage  service
      is braided graphited asbestos.  Never
      use flax as it will result in rapid shaft
      sleeve wear.  Check with the manufacturer
      or service representative.

   4  When inserting packing, push  the first
      ring all of the way back into the housing
      evenly.   Rotate each subsequent ring
      so that the cut ends are staggered 90
      to 180 .  Push each one all of the way
      back into the housing before starting
      the next. Make certain that the lantern
      ring or  seal cage is directly under the
      seal water connection.  Continue adding
      packing rings individually according to
      specifications.  Replace packing gland.
      Take  up slack, then back up to a loose fit.

   5  Inspect  the pump installation before
      startup.  Are your valves, power circuits,
      pump and lines ready to go?  If so,  turn
      on the seal water and start the pump.
      Let the  stuffing box leak freely for 10-15
      minutes, then gradually tighten the packing
      nuts by  hand.  Watch the temperature
      rise; if  packing nuts are tightened too
      rapidly, the packing will heat, glaze and
      possibly score the shaft sleeve.

   6  Caution - never tighten the packing gland
      so that all leakage is stopped.   A slow
      constant drip is what you want.  Check
      daily and adjust as needed.

A  Check the running records.  Have the units
   been serviced on schedule?  Have there
   been notations of characteristics that
   suggest operating difficulty later?

B  Clean the bearings and replace with grease
   or oil as specified on the running record.
   Replace stuffing box packing after cleaning
   the housing as specified on the running
   record.  Check packing gland  leakage and
   freeness. Oil and free-up packing gland
   nuts  and bolts.

C  Check capacity and head to determine if
   wearing ring clearances are OK.  Complete
   overhaul is not ordinarily needed unless
   problems such as reduction in capacity or
   pressure, vibration, high bearing
   temperatures are evident.

   1  If it is necessary to dismantle the pump.
       protect all machined surfaces from
       rust or damage, clean and paint casings,
       check wearing ring clearances with the
       pump manufacturer, check shaft sleeves
       and replace if worn. Check fit at the
       the impeller hub and condition of the
       shaft under the sleeves.  Remember
       that mismatched or poorly fitting
       replacements are likely cause early
       failure.  Either know what you are
       doing or  call in someone who does.
VI     Some of the more common sources of
       trouble are listed below.  The operator
       often can avoid unnecessary expense
       by careful consideration of the causes

 A  Failure  to Deliver Water

    1  Pump not primed

    2  Insufficient speed

    3  Discharge head too high (greater than
       that for which the pump is rated)

    4  Suction lift too high

    5  Impeller passages partially clogged

    6  Wrong direction of rotation

 B  Insufficient Capacity

    1  Air Leaks in suction piping

    2  Speed too low

    3  Total head higher than that for which
       pump is rated

    4  Suction lift too high

    5  Impeller passages partially clogged

    6  Mechanical defects:

       a  Impeller damaged

       b  Wearing rings worn (where applicable)

    7  Foot valve too small or restricted by trash

    8  Foot valve or suction pipe not immersed
       deep enough

 C  Insufficient Discharge Pressure

    1  Speed too low

Pump Maintenance
   2  Air in water

   3  Mechanical defects:

     a  Impeller damaged

     b  Wearing rings worn (where applicable)

D  Pump Loses Prime After Starting

   1  Leaky suction line

   2  Suction lift too high

   3  Air or gases in the liquid

E  Pump Overloads Driver

   1  Speed too high

   2  Liquid pumped of different specific
     gravity and viscosity than that for which
     pump is rated

   3  Mechanical defects

   4  Packing gland too tight causing
     excessive  friction loss in box
F  Pump Vibrates

   1  Misalignment

   2  Foundation not rigid

   3  Impeller partially clogged,  causing

   4  Mechanical defects:

      a  Bent shaft

      b  Rotating element binds

      c  Worn bearings
This outline was prepared from materials
supplied by C. M.  Robertson, Jr. ,  Worthington
Corporation, 1077 Celestial Street,
Cincinnati, OH  45202


A  Pollutants removed from wastewaters
   must be treated in such a way that they
   will not pollute the environment.

   1  A pollutant is a substance that interferes
      with the intended use  of the environment,

   2  Incineration to reduce volume of organic
      wastes must  not lead  to air pollution.

   3  Likewise, the effluent from a scrubber
      used to control air pollution from a
      furnace must be treated to prevent
      water pollution.

   4  Seven places to put wastes.   Outer
      space, air, oceans, fresh water,
      underground, land surface reuse.

   5  Pollutant substances must be rendered
      innocuous either by dilution below
      background level or by locking up in

B  Disposal to Air and Outer Space

   1  Water vapor and CO,,.

   2  Heat.  Thermal pollution kills fish by
      direct action, reduction of DO,  inter-
      ference with reproduction and increased
      susceptibility to disease.

C  Ocean Disposal - Lowest Cost for  Coastal

   1  Potential danger to environment.

   2  Floatable and settleable solids are not
      well diluted.

   3  Food chains may concentrate poisons
      killing larger species.

   4  Barge to deep water and sink to bottom.

   5  Ocean pipeline to deep water and sink
      solids. West Coast.
   6  Ocean diffuser into well mixed area.
      Gulf and East Coast Continental Shelf.
      Sludge beds may suffocate bottom

D  Land Disposal.  Fill or Dump.

   1  Lowest cost for small plants.

   2  Not suitable for soluble substances
      such as salts.

   3  Needs dewatering to produce solid that
      will bear a load.  Useful for insoluble
      inorganic wastes.

   4  Organics will putrefy and decay and
      may produce foul seepage and sub-
      sidence of the surface.

E  Land Disposal.  Surface  spreading and
   Plowing in.

   1  Not suitable for solubles except  nutrients
      in quantities utilized by plants.

   2  Low cost dewatering;  can handle liquid

   3  Low cost oxidation of organic matter.

   4  Many elements locked up on soil

   5  Improves soil for agriculture and

   6  Suitable for small or large plants.
      Chicago uses train, barge and pipeline.

F  Land Disposal. Wells.

   1  Wells into porous formations are
      unsuitable for sludges or liquids con-
      taining filterable solids.

   2  Useful for salt disposal into saline

   3  May leak out and contaminate other
AWT.UD. lb.9.71

 Ultimate Disposal to the Environment
   4  Large volumes may produce earthquakes
      and land movement.

 G Polluting Substances

   Consider pollutants on an element-by-
   element basis.  Fortunately do not have
   101 problems as most elements will not
   be pollutants.

 A Carbon,  Hydrogen, Oxygen,  Nitrogen,
   Phosphorus, Sulfur, Ash.

 B Principal problem in disposal of organic
   sludges in water.  Twenty to fifty times
   as much water as all other substances in

 C Carbon and hydrogen in organic com-
   pounds can be oxidized to CO and HO
   which do not pollute the atmosphere.
   Avoid CO and odor by proper furnace

 D Heat Production

   1  Oxidation of 1 Ib of organic sludges is
      sufficient to evaporate about  2 Ibs of
      water.  Up to 3 Ibs for oily sludge since
      combined O as in carbohydrates reduces
      heating value.

   2  High temperature oxidation uses all the
      heat of combustion to evaporate water
      left in the sludge and usually requires
      excess fuel.

   3  Economics of incineration are therefore
      closely tied to dewatering by sedimentation,
      filtration, and drying.

 E Treatment of Wet Sludge to Aid  Further

   1  Anaerobic digestion.  Reduces solids
      about 50% by hydrolysis and fermentation
      to methane gas which is burned to CO2
      and water.  Produces foul supernatant
      liquor which returns organics and
      nutrients to the plant for recycle.
    2  Sludge cooking at 37QOF.  Porteous
       Process improves filterability of
       solids.  Returns 10-20% of the BOD
       and 60-80% of the nitrogen.

    3  Wet oxidation  - Zimpro at 350op
       removes 15% of COD by oxidation;
       dissolves 25% of solids and 90% of
       nitrogen.  Higher temperatures
       destroy more  solids.   Improves
       filtration, produces a foul supernatant

    4  Aerobic stabilization.  Aerate for
       1-15 days.  Stabilizes  solids but does
       not aid dewatering. Nitrates can be
       destroyed and phosphates held in  solids.

 F Oxidation and dewatering  on land surfaces.
    An "old-fashioned" process.

    1  Organics are oxidized  by soil bacteria.

    2  Nutrients and  other pollutants are fixed
       to a significant extent and kept out of
       water supplies.

    3  Must  control putrefaction and spread
       of pathogens by pretreatment.

 A Composition and Occurrence

    1  Sewage contains orthophosphate,
       polyphosphate and organic phosphates.
       Total P in secondary effluent averages
       near 8 mg/1 as  P (24 as PO ,  18 as
       P Oj.), large fluctuations with place
       and time.

    2  Biological treatment,  which may begin
       in the sewers, hydrolyzes up to 90%  of
       the  phosphates to ortho-  as HPO.
       in secondary effluent.

 B Organic sludges carry a fraction of the
    total P load.

    1  Anaerobic digestion normally returns
       a large fraction of the P  to the plant.

                                                      Ultimate Disposal to the Environment
   2  Combustion retains P in ash.

   3  Land spreading fixes P on soil
     minerals but silt carries P into streams.

C  Lime Sludges
   1  High pH precipitates calcium phosphate
      as Ca  OH (PO )  , hydroxyapatite.
      This is frequently referred to and
      calculated as tricalcium phosphate or
      "tri cal, " Ca (PO ) , which is called
      bone phosphate of lime,  bpl, in Rock
      Phosphate analyses.

   2  Lime dosage of up to 600 mg/1 as
      Ca(OH)  , (450 as Cao) has been used
      to raise pH above 11 and precipitate
      calcium phosphate in tertiary treatment.

   3  Tertiary lime sludge can be dewatered
      easily by sedimentation  and vacuum
      filtration or centrifugation to 25-40%

   4  Burning in a lime kiln or incinerator
      converts CaCO   to CaO.  Calcium
      phosphate is essentially unchanged.

   5  CaO can be slaked to Ca(OH)2 which
      can be  reused.   Calcium phosphate
      remains with inerts including MgO
      which does  not slake.

   6  High phosphate sludge has low
      solubility in water and can be safely
      dumped. May have  market value as
      fertilizer since P is available to
      growing plants.

   7  Recovered lime  costs nearly as much
      as new lime but  partially solves dis-
      posal problem.   Lake Tahoe, California.

   8  Lime treatment of primary reduces
     BOD, SS, and phosphates (Dorr-Oliver).
     Sludge may be hard to dry on sand beds
      but  does not putrefy.

 D Alum  Sludges

   1  Aluminum salts  hydrolyze to aluminum
      hydroxide and precipitate phosphates
      near pH 7.
        Aluminum to phosphate ratio close
        to 2:1.  A1PO. A1(OH)3 probably
        not a pure compound.

        Disposal of aluminum hydroxide
        sludges rich  in organic matter may
        be difficult. Aluminum  phosphates
        are not dissolved in anaerobic
        digesters but sludges are hard to
        thicken.  Lime improves dewater-
 E  Iron Salts

    1   Hydrolyze (and oxidize) to produce
        ferric hydroxide Fe(OH)_ which
        removes phosphates as basic ferric

    2   Ferric phosphate FePO. reduced
        in digesters to ferrous phosphate
        FeJPO )„.   Insoluble but  dis-
        sociatea by H S to form FeS which
        may liberate soluble phosphates.

    3   Possible utility when acid  mine wastes
        or iron pickle liquor is available.
        No recovery of iron.

 A All nitrogen comes from the air and
    ultimately returns to the air.

    1   All forms of N are biologically
        interconvertible.  Report all forms
        of nitrogen as mg/1 N,

    2   All except N  are pollutants.  "Good"
        fertilizers in water.

 B Organic Nitrogen

    1   Burn to N?  gas with some oxides of
        nitrogen if furnace design is inadequate.

    2   Hydrolyze to NH. by anaerobic or
        short time aerobic treatment.

    3   Oxidize to nitrate with long time
        aeration in presence of suitable

Ultimate Disposal to the Environment
C  Inorganic Nitrogen

   1  Ammonia as a pollutant above 1 mg/1 in
     municipal or surface waters.  Not an
     air pollutant but could be reabsorbed
     in waters.

   2  Chlorine destroys ammonia producing
     N  but requires 10 parts of Cl  per
     part of NH -N.

 Chlorine normally is applied to water as a
 bactericidal agent; it reacts with water con-
 taminants to form a variety of products  con-
 taining chlorine.  The difference among
 applied and residual chlorine represents the
 chlorine demand of the water under conditions
 specified.  Wastewater chlorination is parti-
 cularly difficult because the concentration of
 organisms and components susceptible to
 interaction with chlorine are high and variable.
 Interferences with the chlorine determination
 in wastewater confuse interpretation with
 respect to the chlorine residual at a given
 time and condition, its bactericidal potency,
 or  the future behavior.

 A Chlorine compounds (C^) dissolve in water,
   and hydrolyze immediately according to the
                                          exists as hypochlorite ion (OC1 ).  The pH
                                          value that will control is the pH value
                                          reached after the addition of chlorine.
                                          Chlorine  addition tends to lower the pH
                                          and the addition of alkali hypochlorites
                                          tends to raise the pH.

                                        B The initial reactions on adding chlorine to
                                          wastewaters may be assumed to be funda-
                                          mentally the same as when chlorine is
                                          added to water except  for the additional
                                          complications due to contaminants and
                                          their concentration.

                                          Hypochlorous acid (HOC1) reacts with
                                          ammonia and with many other complex
                                          derivatives  of ammonia to produce com-
                                          pounds  known as chloramines. Formation
                                          of the simple ammonia chloramines includes:
                                           1  NHn  +  HOC1  —
 C19 +  HO   ~   HOC1 +  H   + Cl
   The products of this reaction are hypo-
   chlorous and hydrochloric acid.  The re-
   action is reversible,  but at pH values above
   3. 0 and concentrations  of chlorine below
   1000 mg/1 the shift is predominantly to the
   right leading to hypochlorous acid (HOC1).

   Hypochlorous acid is a  weak acid and con-
   sequently ionizes in water according to the
                                                                  HOC1  —
HOC1  r-   H
   This reaction is reversible.  At a pH value
   of 5.0 or below almost all of the chlorine
   is present  as  hypochlorous acid (HOC1)
   whereas above pH 10.0 nearly all  of it
3  NH0C1   +  NHC10 — N0
     &             66
                                                                          3  HC1
                                          The distribution of the ammonia chloramines
                                          is dependent on pH, as illustrated below:
      Percentage of Chlorine Present as
      Monochloramine    Dichloramine
PC. lla. 12.71

  Chlorine  Determination and Their Interpretation
    The formation of the  ammonia chloramines
    are dependent on pH, temperature,  and
    chlorine-ammonia ratio.  Chlorine  re-
    actions with amino acids are likely; pro-
    duct disinfecting powers are lower than
    those of chlorine or of ammonia chloramines.

 A Terms  used with Respect to Application

    1  Pre-chlorination - chlorine added
       prior to any other treatment.

    2  Post-chlorination - chlorine added
       after other treatment.

    3  Split chlorination  - chlorine added  at
       different points in the plant -  may in-
       clude pre- and post -chlorination.

 B Terms  used in Designating Chlorine

    1  Free available residual chlorine -  the
       residual chlorine present as hypo-
       chlorous acid  and hypochlorite ion.

    2  Combined available residual chlorine -
       the residual chlorine present  as chlor-
       amines and organic chlorine containing

    3  Total available residual chlorine - the
       free  available residual chlorine + the
       combined available residual chlorine -
       may represent total amount of chlorine
       residual present  without regard to  type.

       In ordinary usage these terms are
       shortened to free  residual chlorine, com-
       bined residual chlorine and total
       residual chlorine.  In the chlorination
       of wastewaters only combined residual
       chlorine is ordinarily present and is
       often improperly termed chlorine

 C Breakpoint chlorination  specifically refers
    to the ammonia-chlorine reaction where
    applied  chlorine hydrolyzes and  reacts to
    form chloramines and HC1 with the
    chlorarhines eventually forming No + HC1
    as in I.E. 3.  Assuming no other chlorine
    demand, the total chlorine residual will
    rise,  decrease to zero and  rise again with
    increasing increments of applied chlorine.
    Other substances may produce humps in
    the applied chlorine vs residual chlorine
    plot due to oxidation of materials other
    than ammonia.  Sometimes these are
    erroneously considered as a breakpoint.

 The o-Tolidine color test and lodometric
 titration methods are the basis for numerous
 modifications for determining chlorine
 residuals in water.  The relative advantages
 of a specific determination depends upon the
 form in which the reactable chlorine exists
 and the amount and nature of interferences
 in the water.

 lodometric  titration using the amperometric
 endpoint appears to be the most accurate
 residual chlorine method available (See current
 editions of Standard Methods APHA(l) and ASTM
 Standards (2)). The O-Tolidine and o-
 Tolidine Arsenite methods require little
 apparatus, and are readily adapted as a field
 or control test.  The Starch Iodine color
 titration endpoint for iodometric titration
 is suitable  for use on clean water or stock
 solutions and  may be useful on certain types
 of wastewater residuals.  Selection of a suit-
 able method of determining chlorine  residuals
 depends  upon the correlation of the determined
 residual and the  bacterial kill in the  presence
 of existing interferences under applied

 A lodometric Method

    1  Scope and application

       This method is .applicable to the deter-
       mination of total chlorine residual in
       wastewaters, polluted waters and some
       industrial wastewaters.

    2  Summary of method

       When a sample is  treated with  a measured
       excess of standard phenylarsine oxide

                                                  Chlorine Determination and Their Interpretation
      solution,  or a standard thiosulfate
      solution,  followed by the addition of
      iodide, the  iodine liberated at the
      proper pH is stoichiometrically pro-
      portional to the total chlorine present.
      The liberated iodine reacts with the
      phenylarsine oxide or thiosulfate
      before any is lost to other extraneous
      reactions.  The excess phenylarsine
      oxide or thiosulfate is titrated with
      standard iodine solution in the presence
      of starch until the phenylarsine oxide
      or thiosulfate is completely oxidized.
      The end-point of the titration is the next
      addition of standard iodine solution that
      causes a faint blue color to persist in
      the sample.
   3  Interferences

      a  Organic matter - reacts with liber-
         ated iodine.

      b  Manganic  manganese - liberates
         iodine from iodide at pH 4.0.

      c  Ferric iron,  ferricyanide and nitrites
         up to 100 mg/1 do not interfere at a
         pH of 4.0.

      d  Chromates - reduce phenylarsine oxide
         or thiosulfate to an appreciable extent
         before the excess can be titrated with
         standard iodine.

      e  Excessive color and turbidity
B  lodometric Method with Amperometric

   1  Scope and application

      This method is applicable to the deter-
      mination of total chlorine residual in
      wastewaters, polluted waters  and some
      industrial wastewaters.  The back-
      titration method is essential for waste-
      waters in contrast to the direct titration
      with phenyiarsine oxide in clean waters.
2  Summary of method

   When a sample is treated with*a meas-
   ured excess of standard phenylarsine
   oxide solution followed by the addition
   of iodide, the iodine liberated at the
   proper pH is stoichiometrically propor-
   tional to the total chlorine present.
   The iodine liberated reacts with  the
   phenylarsine oxide before any is lost to
   other extraneous reactions.  When the
   cell is immersed in a sample so treated,
   no current is generated due to halogens
   nor is any further current generated,
   as the excess phenylarseneoxide is
   titrated with standard iodine solution
   until the phenylarsine oxide is completely
   oxidized.  The end-point of the titration
   is the next addition of standard iodine
   solution that causes further current
   to be generated and a microammeter
   response or pointer deflection.

   NOTE:  As the end-point is approached
   each increment of standard iodine solu-
   tion causes  a temporary deflection of the
   microammeter, but the pointer drops
   back to about its original position.   The
   true end-point is reached when a small
   addition of standard iodine solution gives
   a definite and permanent pointer deflection.

3  Interferences

   a  Organic matter - reacts  with the
      liberated iodine.

   b  Manganic manganese - liberates
      iodine from iodide at a pH of 4. 0.

   c  Ferric iron, ferricyanide and
      nitrites up to 100 mg/1 do not  inter-
      fere at a pH of 4.0.

   d  Chromates -  reduces phenylarsine
      oxide to an appreciable extent before
      the excess can be titrated with standard
      iodine solution.

   e  Cupric  ions may cause erratic be-
      havior of the  apparatus.

Chlorine Determination and Their Interpretation
         Cuprous and silver ions tend to
         poison the electrode.
C  Orthotolidine Method

   1  Scope and application

      This method is applicable to the deter-
      mination of total chlorine residual in
      wastewaters, polluted waters and some
      industrial wastewaters.

   2  Summary of method

      When a sample is treated with a meas-
      ured amount of Orthotolidine reagent, the
      orthotolidine is oxidized in the resulting
      acid  solution by chlorine and chloramines
      and other oxidizing agents to produce a
      yellow-colored compound (Holoquinone).
      The color produced at pH values  of less
      than  1. 8 is proportional to the amount
      of chlorine present and is suitable for
      quantitative measurement.  The chlorine
      residual in mg/1 is read directly from
      the colored glass disks  or sealed
      colored  liquid  standards or is calculated
      from a previously prepared standard
      curve.  NOTE:  Particular attention
      is called to the importance of warming
      the sample to 20°C after the addition
      of orthotolidine reagent in order to
      complete the reaction.

   3  Interferences

      a  Organic matter -  oxidizes orthotolidine
        to produce a yellow color (Holo-
        quinone) .

      b  Manganic manganese - in concentra-
        tions  above  0.01 mg/1 oxidizes
        orthotolidine to produce a yellow
        color (Holoquinone).

      c  Ferric iron - in concentrations above
        0. 3 mg/1 oxidizes orthotolidine to
        produce a yellow color (Holoquinone).

      d  Nitrites - in concentrations above
        0. 10 mg/1 of nitrite nitrogen oxidizes
        orthotolidine to produce a yellow
        color (Holoquinone).
    e  Excessive color and turbidity.
 D  Orthotolidine- Arsenite Method

    1  Scope and application

       This method is applicable to the deter-
       mination of free residue chlorine and
       combined residual chlorine  in waste -
       waters,  polluted waters and industrial
       wastewaters, but as normally carried
       out for wastewaters, etc. total residual
       chlorine  is measured.

    2  Summary of method

       A sample is split into two fractions (a)
       and (b).   Sample (a) is treated with a
       measured amount of arsenite reagent,
       followed  by the addition of orthotolidine
       reagent.   The  arsenite reacts with
       chlorine  while orthotolidine reacts with
       ferric iron,  manganic manganese  and
       nitrite nitrogen to produce additional
       color (represents interfering color).
       Sample (b) is treated with a measured
       amount of orthotolidine  reagent.  The
       orthotolidine is oxidized in the  resulting
       acid solution by chlorine, chloramines
       and other oxidizing agents to produce
       a yellow-colored compound (Holoquinone)
       as described in the orthotolidine method
       (represents total amount of  residual
       chlorine present and interfering color).
       Mg/1 total residual chlorine = b - a if
       color compensation is not made directly.
       NOTE: more accurate readings may be
       obtained if cells containing sample
       fractions (a) and (b) are placed in the
       comparator in such relative positions
       that color compensation is made

    3  Interferences

       a High color and turbidity

 In general residual chlorine concentrations
 obtained by the iodometric titration method
 (starch iodide end-point and amperometric

                                             Chlorine Determination and Their Interpretation
end-point) will be higher than the concentrations
obtained from the orthotolidine and the orthoto-
lidine-arsenite methods.  Some of the reasons
for the difference have been listed under the
individual methods.  Extensive studies have
indicated that consistently better correlation
between  bacterial kill and chlorine residual
found is  possible when the titration method
is used.

1    Standard Methods for the Examination of
      Water and Wastewaters,  13th Ed.,
      APHA,  AWWA, WPCF. 1971.

2    Book of ASTM Standards. Part 23-
      Industrial Water; Atmospheric
      Analysis.  American Society for
      Testing and Materials.
      Philadelphia,  Pa., 1970.

3  Sawyer,  C.N.  Chemistry for Sanitary
      Engineers.  McGraw-Hill Book Com-
      pany,  New York.   1960.
4  Moore,  E. W.  Fundamentals of Chlori-
      nation of Sewage and Wastes.   Water
      and Sewage Works.  Vol.  98. No.  3.
      March 1951.

5  Day, R. V.,  Horchler,  D. H.,  and Marks,
      H. C.  Residual Chlorine  Methods and
      Disinfection of Sewage.  Industrial and
      Engineering Chemistry,  May  1953.

6  Marks,  H. C., Joiner,  R. R.,  and
      Strandskov, F. B.  Amperometric
      Titration of Residual Chlorine in
      Sewage.   Water and Sewage Works,
      May  1948.
This outline was prepared by J. L. Holdaway,
Chemist, Technical Proeram, EPA, Region III,
CharlottesviUe, VA  22901.

                               WASTEWATER DISINFECTION

A  In a recent survey of all municipal sewage
   treatment plants, it was reported that an
   overall 30% of treatment plants were
   provided with facilities for introduction
   of chlorine in connection with treatment
   plant operations.

   Briefly, the survey of treatment plants
   utilizing chlorine may be summarized
   in Table  1.

B  In reviewing publications relating to the
   use of  chlorine with relation to wastewaters,
   the uninitiated worker quickly can gain an
   impression that chlorine is  used in waste-
   water treatment operations  as an almost-
   universal panacea, as a means of solving
   whatever problems seem to be plaguing
   the operations of the particular plant  at
   the time.
    The purpose of this discussion is to
    review the basic principles of
    chlorination, and discuss its use for
    wastewater disinfection.

 In terms of its significance in wastewater
 treatment processes, the important
 properties of chlorine include the following:

 A  Chlorine is a powerful oxidizing agent.

 B  Chlorine is poisonous to living organisms.

    1  The poisonous properties of chlorine
      probably are exerted through its
      oxidizing ability, through which enzyme
      systems essential to life are
      irreversibly oxidized, or at least
      are inactivated.

Population served
Less than 1, 000
1, 000 to 5, 000
5,000 to 10,000
10,000 to 25, 000
25,000 to 50,000
50,000 to 100,000
More than 100, 000
Total number
of plants
Plants with

Percentage with

Wastewater Disinfection
      According to the category of organisms
      for which chlorine is being used as a
      poison,  chlorine could be  called a
      germicide, a bactericide, a disinfecting
      agent, an algicide,  an ovocide, a
      cysticide, or by any of several other
      "-cide" terms.

      Different  categories of organisms
      differ widely in their susceptibility to
      chlorine.  Figure 1 illustrates the
      relative susceptibility of Escherichia
      coli and three different kinds of
      viruses,  to hypochlorous acid.  Note
      that those relationships are attributable
      to a "free" chlorine residual and a
      "pure" culture.  This is not in a

      The rate at which the disinfecting
      (killing) process takes place is variable,
      and subject to control through manage-
      ment of such interrelated factors as
      temperature,  concentration, pH, and
      the amount,  kind, and physical state
      of other suspended and dissolved sub-
      stances present in the water.
     Chlorine is highly soluble in water, and
     can be introduced economically into water
     and wastewater with accuracy and with
     adequate provision to protect the health
     and safety of operational personnel and
     the population which will be exposed to
     contact with the chlorine-treated waters.

 A Terms used with respect to application

    1  Pre-chlorination -  chlorine added
       prior to any other treatment

    2  Post-chlorination - chlorine added
       after other treatment

    3  Split chlorination -  chlorine added at
       different points in the plant - may
       include pre- and post-chlorination

 B Terms used in defining chlorine residuals

    1  Chlorine dosage is the amount  of
       chlorine added to a  water or waste-
       water at the point of injection.
                      -   .10
                      2  .010
                            E  i  v M  M  \ i   i  i rtj i    i   i  in  IE
                                   C. COU
                                   tOENOVIRUS 3
               \   _
                \   -
                 \  -
                  \ -
                               I  I  I I I I  I    I  I  I  l\l I    I   I  I l\l
                           .1   .2 .3 .4.5 6 .8 1.0   1  34566 10

                                                               3040    80100
                         Of j_ COLI AND 3 VIRUSES BY  HTPOCHLOROUS ACID |HOCI| AT 0 • E°C

                                           FIGURE 1

                                                                  Wastewater Disinfection
      Chlorine demand is the amount of the
      chlorine dosage which is utilized to
      oxidize or combine with organic or
      inorganic substances present, and
      results in a chlorine  compound which
      is of no value for disinfection.

      Residual chlorine is the amount of
      chlorine remaining after the chlorine
      demand has been satisfied.
      chlorine dosage - chlorine demand =
      chlorine residual.

 A Most commonly,  chlorine is added to
    water in solution,  being kept in tanks in
    liquid form under pressure; the liquid
    chlorine is converted to gas which in turn
    is dissolved into the water or wastewater
    being treated.
    Chlorine gas (CU) dissolves in water, and
    hydrolyzes immediately according to the
   4  Free available residual chlorine - the
      residual chlorine present as
      hypochlorous acid and hypochlorite ion.

   5  Combined available residual chlorine -
      the residual chlorine present as

   6  Total available residual chlorine - the
      free available residual chlorine + the
      combined available residual - may
      represent total amount of chlorine
      residual present without regard to type.

      In ordinary usage these terms are
      shortened to free residual chlorine,
      combined residual  chlorine and total
      residual chlorine.

      In the chlorination  of wastewaters only
      combined residual  chlorine is ordinarily
      present and is often improperly termed
      chlorine residual.

C  Breakpoint chlorination  specifically refers
   to the ammonia-chlorine reaction where
   applied chlorine hydrolyzes and reacts to
   form chloramines and HC1 with the
   chloramines eventually forming N  + HC1.
   Assuming no other chlorine demand, the
   total chlorine residual will rise, decrease
   to zero and rise again with increasing
   increments of applied chlorine. Other
   substances may produce humps in the
   applied chlorine vs residual chlorine plot
   due to oxidation of materials other than
   ammonia.  Sometimes these are erroneously
   considered as a breakpoint.
     HOC1 = H  + Cl
    The products of this reaction are
    hypochlorous and hydrochloric acid.
    The reaction is  reversible, but at pH
    values above 3. 0 and concentrations of
    chlorine below 1000 mg/lthe shift is
    predominantly to the right leading to
    hypochlorous acid (HOC1).

    Hypochlorous acid is a weak acid and
    consequently ionizes in water according
    to the equation:
This reaction is reversible.  At a pH
value of 5. 0 or below almost all of the
chlorine is present as hypochlorous acid
(HOC1) whereas above pH 10. 0 nearly all
of it exists as hypochlorite ion (OCl").
The pH value that will control is the pH
value reached after the  addition of chlorine.
Chlorine addition tends  to lower the pH
and the addition of alkali hypochlorites
tends to raise the pH.

The initial reactions on adding chlorine
to wastewaters may be assumed to be
fundamentally the same as when chlorine
is added to water except for the additional
complications due to contaminants and
their concentration.

Wastewater Disinfection
   Hypochlorous acid (HOC1) reacts with
   ammonia and with many other complex
   derivatives of ammonia to produce
   compounds known as chloramines.
   Formation of the simple ammonia
   chloramines includes:
                                          product disinfecting powers are lower
                                          than those of chlorine or of ammonia
                                      V  DISINFECTION OF WASTEWATERS
   1  NH3 + HOC1 •
   2  NH.C1 +  HOC1-*  NHC10 +  H0O
         £t                    Ct     dt
   3  NHC10 +  HOC1-
   4  NH_C1 +  NHC10 -" N   + 3HC1
         fl            £l     Cl
   Chloramines are formed in water con-
   taining ammonia; when chlorine is added,
   a mixture of monochloramine (NH Cl),
   and dichloramine (NHC1-), are formed.

   If enough chlorine is added to react with
   all the available NH and still leave an
   excess of chlorine, then nitrogen
   trichloride (NC1_) may be formed.
   Chloramines are less reactive chemically
   and less effective as germicides, than
   are the free forms of chlorine.

   The distribution of the ammonia chloramines
   is dependent on pH, as illustrated below:
                 TABLE 2
Percentage of Chlorine Present as

Monochloramine    Dichloramine
   The formation of the ammonia chloramines
   is also dependent on temperature, and
   chlorine-ammonia ratio.  Chlorine
   reactions with amino acids are also likely;
A  Sewage is known to contain tremendous
   numbers of microorganism of intestinal
   origin.  Individuals harboring pathogenic
   organisms including bacteria viruses
   protozoa and other forms of disease
   producing organisms are likely in any
   population.  Discharges from infected
   persons constitute a hazard to the health
   and safety of individual coming into
   contact with such sewage or treatment
   plant effluents unless disinfected.

   1  In recent years, an epidemic of infectious
      hepatitis was traced to shellfish harvested
      from polluted waters in Raritan Bay. A
      pollution study of some magnitude was
      initiated, and considerable numbers
      of bacteria attributable to waste treat-
      ment plants adjoining Raritan Bay
      were demonstrated in the  study. During
      the period when wastewater treatment
      plants  chlorinated the treatment plant
      effluents, enteric pathogenic bacteria
      could not be recovered.   However,
      when chlorination of treatment plant
      effluents was discontinued, Salmonella
      were discovered with some regularity
      at sampling points related to the above
      waste treatment plant discharges.

   2  In studies of the Red River of the North,
      Salmonella has been discovered with
      great regularity in waters polluted
      through discharge of inadequately
      treated wastewaters.  In some cases,
      Salmonella has been discovered where
      the fecal coliform count was only a few
      hundreds per 100 ml.

B  Objective

   Many people feel that we should base
   chlorination levels on the presence of,
   or number of actual pathogenic organisms
   present, but as yet this is neither feasible
   nor warranted, and we still use the
   coliform indicator organisms.  The
   density of these in wastewaters vary

                                                                    Wastewater Disinfection
   greatly, and if positive information is
   desired must be determined for each
   plant.  Table 3 shows some typical
   residential densities.
                                          TABLE 3

Residential "A"
Residential "B"
Residential "C"
Residential "D"
1,940, 000
6,300, 000
Densities, Count/ 100
10,900, 000
340, 000
1, 720, 000
4, 000, 000
2,470, 000
64, 000

C  Chlorination Efficiency

   Chlorine functions as a disinfectant in the
   sense that it is applied in dosages con-
   sidered sufficient to destroy the pathogenic
   (disease-causing) organisms.  Disinfection
   is not construed to mean total destruction
   of all living organisms present in the
   sewage  effluents (sterilization).

   For disinfection, chlorine must be added
   in sufficient concentration,  and with a
   sufficient contact time, to ensure
   destruction of the pathogenic bacteria.
   However, this inactivation is evaluated
   by coliform inactivation.

   1 Much outdated information is available
     regarding the efficiency of chlorine in
     wastewaters, and certain literature
     claims chlorine efficiencies equal to
     or greater than the efficiencies in clean
     water. One basis  of chlorine application
     for disinfection,  widely noted in test-
     books of sanitary engineering practices,
     provides recommendations for adequate
     disinfection by adding chlorine in an
     amount sufficient to kill 99. 9% of all
coliform bacteria in the sewage, or
sewage effluent,  after a contact time
of 15 minutes,  and to have a chlorine
residual of 0.5 mg/liter (according to
one recommendation, the residual
chlorine should be 2 mg/liter). A
widely-quoted table of chlorine
application follows in Table 4.

2  The efficiency of chlorine as a
   disinfectant is affected by pH,
   temperature,  contact time, con-
   centration,  solids present,  and a
   number of other variables.  The
   attached Figure 2 shows some
   excellent  data regarding efficiency
   of chlorine in  clear water.  Obviously
   chlorine will not be equally/nor more
   effective in wastewater.  By looking at
   the attached Figure 3 you can see this
   is true.

   The data in  Figure 3 has also been
   essentially verified by other
   investigators.  Based upon  what we
   know of chlorination in water,  these
   data appear quite reasonable.

 Wastewater Disinfection
                                            TABLE 4

      Amounts of Chlorine required for Disinfection of Sewage and Sewage Effluents with
             Chlorine Residual 0.5 mg/liter after Contact Time of 15 Minutes
       Type of Sewage or Effluent
  Probable Chlorine
 mg/liter   lb/day/1000
 Chlorinator Capacities*
 mg/liter   lb/day/1000
    Raw sewage, depending on strength  6-25
    and staleness
    *For sewage flow of 100 gallons per capita per day.
Settled Sewage
Chemically precipitated sewage
Trickling filter effluent
Activated sludge effluent
Intermittent sand filter effluent
1- 3

 It is not the purpose of this discussion to
 recommend chlorine dosages applicable to
 various types of waste treatment operations.
 Chlorine dosage standards are the prerog-
 ative of the various regulatory agencies.
 The main objective here is to provide a basic
 understanding of some of the important
 factors that affect the efficiency of chlorination
 in controlling bacteria and viruses in sewage
 effluents.  Research data and examples from
 practical operation, along with reference
 material in the  literature, have been com-
 bined here to provide a starting base.  This
 information should be evaluated for its
 relevance to specific plant situations and,
 where appropriate and pertinent,  can then be
 used to provide  guidelines for practical
 disinfection applications in the plant.

 It is emphasized that chlorination of sewage
 effluents is a vastly more complex and
 unpredictable operation than chlorination of
 water supplies.   It is extremely difficult to
 maintain a high, uniform,  and predictable
 level of disinfecting efficiency in any but the
 most efficiently operated waste treatment
 plants. One should strive for the maximum
 level of oxidation attainable because a

 *C.W. Chambers
             completely oxidized and highly clarified
             effluent is easy to disinfect.  On the basis
             of information presented in this discussion,
             along with that obtained by the author in the
             laboratory investigation of germicides, it is
             concluded that the following general guide-
             lines are applicable in varying degree to the
             practical disinfection of sewage treatment
             plant effluents with chlorine.

                1 The coliform test is the primary
                  standard for determining the bacteri-
                  ological quality of water and should be
                  similarly used for evaluating the
                  disinfecting effectiveness  of chlorination
                  in sewage effluents.

                2 While any of the standard  chlorine
                  residual tests may be used,  the
                  amperometric test is the most reliable.

                3 The disinfecting action of  free available
                  chlorine (hypochlorous acid) is much
                  more potent than that of monochloramine.

                4 The effects of pH and temperature
                  should be considered.  Alkaline wastes
                  are more difficult to disinfect,
                  especially during periods  of low

                                                                  Wastewater Disinfection
                            30 MINUTE CHLORINE RESIDUALS

                    National Academy of Sciences, National Research Council

             ^   1.0
                         Consumption of waters containing high
                         chlorine residuals is not  likely to be
                         tolerated  their use without adequate
                         dechlorination is not recommended
                      - MINIMUM RECOMMENDED  RESIDUAL    .4$,
   7.0      8.0     9.0

                                          FIGURE 2

National Academy of Sciences,  National Research Council

Wastewater Disinfection
              0                 0.5                1.0                1.5               2.0
                                   AMPEROMETRIC  RESIDUAL, mg/l
             Percent coliforms and T2 bacteriophage remaining  vs.  ampherometric residual
                      after different  detention times  in trickling filter  effluent.
              Burns  and  Sproul (16). Courtesy Journal Water Pollution Control Federation.

                                               FIGURE 3

                                                               Wastewater Disinfection
For practical planning purposes, the
disinfecting effect of residual chlorine
can be assumed to be monochloramine
or less germicidal forms.

Chlorine dosage is a less significant
factor than contact time but either,  if
excessively increased,  will reach a
point  of diminishing returns.

Flow  in sewage lines should be main-
tained at maximum practical levels to
assure the freshest  influent possible.
Septic sewage is high in ammonia and
sulfides and therefore very difficult and
expensive to disinfect.

Caution should be  exercised in returning
digester supernatant liquor to the
primary tank influent; otherwise,  high
chlorine demands  may occur and pro-
duce an effluent that is  difficult to

Where possible, chlorine demand
schedules should be  developed in order
that chlorine feed  rates may be adjusted
to the varying retirements necessary
to yield the desired  coliform reduction.
10  Two-stage chlorination is more effective
    for disinfection than single-stage

11  Good mixing of chlorine with the effluent
    is essential to consistently produce an
    effluent of uniform coliform content.

12  Settled primary effluents are more
    difficult to chlorinate to a specified
    coliform content than secondary effluents,
    and those from well-operated,  more
    advanced waste treatment plants are
    relatively easy to disinfect.

13  Each plant must develop its own data for
    correlating chlorine dosage,  residual,
    and holding time to yield predictably the
    desired reduction in coliform content.

 In view of the present limited efforts to
 evaluate the effectiveness of chlorination in
 terms of the bacterial quality of effluents
 discharged, I would again quote for your
 serious consideration today a guideline
 offered by Chamberlin (37) more than 20
 years ago.  Concerning the use of chlorine,
 he said "... .the best advice.. . .is to
 chlorinate intelligently, but not blindly. "

 This outline was prepared by  D. J. Hernandez,
 Sanitary Engineer, PNWL, FWQA,
 Corvallis,  ORf

                         METHODS WHICH MAY BE USED TO DETECT
                               INDUSTRIAL WASTE PROBLEMS
 I  Prepare, adopt and enforce a sewer
 ordinance that will regulate the use and
 discharge of wastes into the public sewer
 system.  (See model sewer ordinance).

 A model sewer ordinance can.be obtained
 from the Water Pollution Control Federation
 and can be readily adapted to fit the individual
 C Neutralizing to adjust the pH to acceptable

 D Aerating to restore dissolved oxygen.

 E Coagulating with chemicals or air to
    remove grease, oil or toxic materials.

 F Skimming to control floating material.
 n  Develop an industrial waste inventory of
 all industries that are connected to the sewer

 A  Name and address of the company.

 B  Name, address, and telephone number of
    person in responsible charge.

 C  Nature of manufacturing process, i. e.,
    what do they produce or process.

 D  Nature and quantity of wastes to be discharged.
Ill  Pretreatment of industrial wastes may be
 necessary to meet the conditions set forth in
 the ordinance.  Pretreatment may require one
 or more of the  following:

 A  Screening to remove solids that could
    interfere with the treatment process.

 B  Settling to remove settleable solids and
    sludge or mud before discharge to the
IV  Tracing of oil and other petroleum wastes
 can often be accomplished by anchoring small
 blocks of painted wood in manholes where
 they will become coated with oil or grease.
 By a process of elimination,  the source can
 be pinpointed.  Other items that can be used

 A  Recording pH and D. O.  meters that will
    record any significant change in the waste
    with respect  to pH and D.O.

 B  Automatic samplers that will composite
    a representative sample of the waste over
    a given period of time.  Laboratory
    analyses may reveal a specific component
    that can be traced to its origin.

 C  Portable flow recorder that can be installed
    in manholes to measure the sewage flow
    from a given area.
 This outline was prepared by Edgar R.  Lynd,
 Municipal Waste Treatment Program,
 Oregon State Sanitary Authority,  Portland,
 SE.MAN.6. 11.68

                             THE MODEL SEWER ORDINANCE
OF	.

     Be it ordained and enacted by the Council of the City of

State of                               as follows:
                                        ARTICLE I

      Unless the context specifically indicates otherwise, the meaning of terms used in this
ordinance shall be as follows:

Sec. 1.      "BOD" (denoting Biochemical Oxygen Demand) shall mean the quantity of oxygen
      utilized in the biochemical oxidation of organic matter under standard laboratory
      procedure in five (5) days at 20°C, expressed in milligrams per liter.

Sec. 2.      "Building Drain" shall mean that part of the lowest horizontal piping of a drainage
      system which receives the discharge from soil, waste, and other drainage pipes inside
      the walls of the building and conveys  it to the building sewer,  beginning five  (5) feet
      (1.5 meters) outside the inner face of the building wall.

Sec. 3.      "Building Sewer" shall mean the extension from the building drain to the public
      sewer or other place of disposal.

Sec. 4.      "Combined Sewer" shall mean a sewer  receiving both surface runoff and sewage.

Sec. 5.      "Garbage" shall mean solid wastes from the  domestic and commercial preparation,
      cooking, and dispensing of food, and  from the handling,  storage, and sale of produce.

Sec. 6.      "industrial Wastes" shall mean the liquid wastes from industrial manufacturing
      processes,  trade,  or business as distinct from sanitary sewage.

Sec. 7.      "Natural Outlet" shall mean any outlet into a watercourse, pond, ditch,  lake, or
      other body of surface or ground water.

Sec. 8.      "Person" shall mean  any individual, firm,  company, association, society,
      corporation, or group.

Sec. 9.      "pH" shall mean the logarithm  of the reciprocal of the weight of hydrogen ions
      in grams per liter of solution.
SE.MAN.7. 11.68                                                                      39-1

The Model Sewer Ordinance
Sec. 10.   "Properly Shredded Garbage" shall mean the wastes from the preparation,
      cooking, and dispensing of food that have been shredded to such a degree that all
      particles will be carried freely under the flow conditions normally prevailing in
      public sewers,  with no particle greater than one-half (1/2) inch (1.27 centimeters)
      in any dimension.

Sec. 11.   "Public Sewer" shall mean a sewer in which all owners of abutting properties
      have equal rights, and is controlled by public authority.

Sec. 12.   "Sanitary Sewer" shall mean a sewer which carries sewage and to which storm,
      surface, and groundwaters are not intentionally admitted.

Sec. 13.   "Sewage" shall mean a combination of the water-carried wastes from residences,
      business buildings,  institutions, and industrial establishments, together with such
      ground,  surface, and stormwaters as may be present.

Sec. 14.   "Sewage Treatment Plant" shall mean any arrangement of devices and structures
      used for treating sewage.

Sec. 15.   "Sewage Works" shall mean all facilities for collecting,  pumping, treating, and
      disposing of sewage.

Sec. 16.   "Sewer" shall mean a  pipe or conduit for carrying sewage.

Sec. 17.   "Shall" is mandatory;  "May" is permissive.

Sec. 18.   "Slug" shall mean any discharge of water,  sewage, or industrial waste which in
      concentration of any  given constituent or in quantity of flow exceeds for any period of
      duration longer than  fifteen (15) minutes more than five (5) times the average twenty-
      four (24) hour  concentration or flows during normal operation.

Sec. 19.   "Storm Drain" (sometimes termed "storm sewer") shall mean a sewer which
      carries  storm and surface waters and drainage,  but  excludes sewage and industrial
      wastes,  other  than unpolluted cooling water.

Sec. 20.   "Superintendent" shall mean  the (Superintendent of Sewage Works and/or  of
      Water Pollution Control) of the (city) of (         ),  or his authorized deputy, agent,
      or representative.

Sec. 21.   "Suspended Solids" shall mean solids that either float on the  surface  of,  or are
      in suspension in water,  sewage, or other liquids, and which are removable by
      laboratory filtering.

Sec. 22.   "Watercourse" shall mean a  channel in  which a flow of water occurs, either
      continuously or intermittently.

Sec. 23.   "Hearing Board" shall mean  that Board appointed according to provision of
     Article (   ).  (This section to be included  only if optional article entitled "Hearing
      Boards" is made a part of the ordinance.)

                                                                The Model Sewer Ordinance
                                         ARTICLE II

                                Use of Public Sewers Required

Sec. 1.    It shall be unlawful for any person to place, deposit,  or permit to be deposited
      in any unsanitary manner on public or private property within the (city) of (      ),  or
      in any area under the jurisdiction of said (city), any human or animal excrement,
      garbage, or other objectionable waste.

Sec. 2.    It shall be unlawful to discharge to any natural outlet within the (city) of (     ),
      or in any area under the jurisdiction of said (city), any sewage or other polluted
      waters, except where suitable treatment has been provided in accordance with sub-
      sequent provisions of this ordinance.

Sec. 3.    Except as hereinafter provided,  it shall be unlawful to construct or maintain any
      privy,  privy vault,  septic tank,  cesspool, or other facility intended or used for the
      disposal of sewage.

Sec. 4.    The owner of  all houses,  buildings, or properties used for human occupancy,
      employment,  recreation, or other purposes, situated  within the (city) and abutting
      on any  street, alley, or right-of-way in which there is now located or may in the
      future be located a public sanitary or combined  sewer of the (city),  is hereby required
      at his expense to install suitable toilet facilities therein, and to connect such facilities
      directly with the proper public  sewer in accordance with the provisions of this ordinance,
      within (ninety (90) days) after date of official notice to do so,  provided that said public
      sewer is within (one hundred (100) feet (30. 5 meters)) of the property line.

                                        ARTICLE III
                                   Private Sewage Disposal

Sec. 1.    Where a public sanitary or combined sewer is not available under the provisions
      of Article II,  Section 4, the building sewer shall be connected to a private sewage
      disposal system complying with the provisions of this article.

Sec. 2.    Before  commencement of construction of a private sewage disposal system the
      owner shall first obtain a written permit signed by the (Superintendent).  The application
      for such permit  shall be made on a form furnished by the (city), which the  applicant
      shall supplement by  any plans,  specifications,  and other information as are deemed
      necessary by the (Superintendent).  A permit and inspection fee of (     ) dollars shall
      be paid to the (city) at the time the application is filed.

Sec. 3.    A permit for a private sewage disposal system shall not become effective until
      the installation is completed to the satisfaction of the (Superintendent).  He shall be
      allowed to inspect the work at any stage of construction  and, in  any event, the applicant
      for the permit shall  notify the (Superintendent) when the work is ready for final
      inspection, and before any underground portions are  covered.  The inspection  shall be
      made within (      )  hours of the receipt of notice by  the (Superintendent).

The Model Sewer Ordinance
Sec. 4.     The type, capacities, location, and layout of a private sewage disposal system
      shall comply with all recommendations of the Department of Public Health of the
      State of (       ).  No permit shall be issued for any private sewage disposal system
      employing subsurface soil absorption facilities  where the area of the lot is less  than
      (        ) square feet (square meters).  No septic tank or cesspool shall be permitted
      to discharge to any natural outlet.

Sec. 5.     At such time as a public sewer becomes available to a property served by a
      private sewage disposal system, as provided in Article III, Section 4,  a direct
      connection shall be made to the public sewer in compliance with this ordinance,  and
      any septic tanks,  cesspools, and similar private sewage disposal facilities shall be
      abandoned and filled with suitable material.

Sec. 6.     The owner shall operate and maintain  the private  sewage disposal facilities in a
      sanitary manner at all times, at no expense to the (city).

Sec. 7.     No statement contained in this article  shall be construed to interfere with  any
      additional requirements that may b^ imposed by the Health Officer.

Sec. 8.     When a public sewer  becomes available, the building sewer shall be  connected
      to said sewer within sixty (60) days and the private sewage disposal system shall be
      cleaned of sludge and filled with clean bank-run gravel or dirt.
                                        ARTICLE IV
                               Building Sewers and Connections

Sec. 1.    No unauthorized person shall uncover,  make any connections with or opening
      into, use,  alter, or disturb any public sewer or appurtenance thereof without first
      obtaining a written permit from the (Superintendent).

Sec. 2.    There shall be two (2) classes of building sewer permits:  (a) for residential and
      commercial service, and (b) for service to establishments producing industrial wastes.
      In either case, the owner or his agent shall make application on a special form furnished
      by the (city). The permit application  shall be supplemented by any plans, specifications,
      or other information considered pertinent in the judgment of the (Superintendent).  A
      permit and inspection fee of (      ) dollars for a residential or commercial building
      sewer permit and (     ) dollars for an industrial building sewer permit shall be paid
      to the (city) at the time the application is filed.

Sec. 3.    All costs and expense incident to the installation and connection of the building
      sewer shall be borne by the owner. The owner shall indemnify the (city) from any
      loss or damage that may directly or indirectly be occasioned by the installation of the
      building sewer.

Sec. 4.    A separate and independent building sewer shall be provided for every building;
      except where one building stands at the rear of another on an interior lot and no
      private sewer is available or can be constructed to the rear building through an adjoining
      alley, court, yard,  or driveway,  the building sewer from the front building may be
      extended to the rear building and the whole considered as one building sewer.

                                                                The Model Sewer Ordinance
Sec. 5.     Old building sewers may be used in connection with new buildings only when they
      are found, on examination and test by the (Superintendent), to meet all requirements
      of this ordinance.

Sec. 6.     The size, slope,  alignment,  materials of construction of a building sewer, and
      the methods to be used in excavating,  placing of the pipe, jointing,  testing,  and back-
      filling the trench, shall all conform to the requirements of the building and  plumbing
      code or other applicable  rules and regulations of the (city).  In the absence  of code
      provisions or in amplification thereof, the materials and procedures set forth in
      appropriate  specifications of the A . S. T. M.  andW.P.C.F. Manual of Practice No. 9
      shall apply.

Sec. 7.     Whenever possible, the building sewer shall be brought  to the building at an
      elevation below the basement floor.  In all buildings in which any building drain is
      too low to permit gravity flow to the public sewer, sanitary sewage carried by such
      building drain shall be  lifted by an approved means and discharged to the building sewer.

Sec. 8.     No person shall make connection of roof downspouts, exterior foundation drains,
      areaway drains, or other sources of surface runoff or groundwater to a building sewer
      or building drain which in turn is connected  directly or indirectly to a public sanitary

Sec. 9.     The connection of the building sewer into the public sewer shall conform to the
      requirements of the building and plumbing code or other applicable rules and regulations
      of the (city), or the procedures set forth in appropriate specifications of the A. S. T. M.
      and the W.P. C. F.  Manual of Practice No.  9. All such connections shall be made
      gastight and watertight.  Any deviation from the prescribed procedures and materials
      must be approved by the  (Superintendent)before  installation.

Sec. 10.    The applicant for the building sewer permit shall notify  the (Superintendent) when
      the building  sewer  is ready for inspection and connection to the public sewer.   The
      connection shall be made under the supervision of the (Superintendent) or his

Sec. 11.    All excavations for building sewer  installation shall be adequately guarded with
      barricades and lights so  as to protect the public from hazard.  Streets, sidewalks,
      parkways, and other public property disturbed in the course of the work shall be
      restored in a manner satisfactory to the  (city).

                                        ARTICLE V
                                  Use of the Public Sewers
Sec. 1.    No person shall discharge or cause to be discharged any stormwater, surface
      water,  ground water,  roof runoff,  subsurface drainage, uncontaminated cooling water,
      or unpolluted industrial process waters to any sanitary sewer.

Sec. 2.    Stormwater and all other unpolluted drainage shall be discharged to such sewers
      as are  specifically designated as combined sewers or storm sewers, or to a natural
      outlet approved by the (Superintendent).  Industrial cooling water or unpolluted process
      waters may be discharged, on approval of the (Superintendent),  to a storm sewer,
      combined sewer,  or natural outlet.


The Model Sewer Ordinance
Sec. 3.     No person shall discharge or cause to be discharged any of the following
      described waters or wastes to any public sewers:

      (a) Any gasoline,  benzene, naphtha,  fuel oil,  or other flammable or explosive liquid,
         solid,  or gas.

      (b) Any waters or wastes containing toxic or poisonous solids,  liquids, or gases in
         sufficient quantity, either singly or by interaction with other wastes to injure or
         interfere with any sewage treatment process, constitute a hazard to humans or
         animals,  create a public  nuisance, or create any hazard in the receiving waters
         of the sewage treatment plant, including but not limited to cyanides in excess of
         two (2)  mg/1 as CN in the wastes as discharged to the public sewer.

      (c) Any waters or wastes having a pH lower than (5. 5), or having any other corrosive
         property capable of causing damage or hazard to structures,  equipment, and
         personnel of the sewage works.

      (d) Solid or viscous substances in quantities or of such size capable of causing
         obstruction to the flow in  sewers, or other interference with the proper operation
         of the sewage works such as,  but not limited to,  ashes,  cinders, sand,  mud,
         straw,  shavings, metal,  glass,  rags,  feathers, tar, plastics, wood, unground
         garbage,  whole blood, paunch manure,  hair and fleshings, entrails and paper
         dishes, cups,  milk containers, etc. either whole or ground by garbage grinders.

Sec. 4.     No person shall discharge or cause to be discharged the following described
      substances,  materials, waters, or wastes if it appears likely in the opinion of the
      (Superintendent) that  such wastes  can harm either the sewers, sewage  treatment process,
      or equipment,  have an adverse effect on the receiving stream, or can otherwise endanger
      life,  limb,  public property, or constitute a nuisance.  In forming his opinion as to the
      acceptability of these wastes,  the (Superintendent) will give consideration to such factors
      as to quantities of subject wastes  in relation to flows and velocities in the sewers,
      materials of construction of the sewers, nature of the sewage treatment process,
      capacity of  the sewage treatment plant, degree of treatability of wastes in the sewage
      treatment plant, and other pertinent factors.  The substances prohibited  are:

      (a) Any liquid or vapor having a temperature higher than  one hundred fifty (150)°F
         (650 C).

      (b) Any water or waste containing fats, was, grease, or oils, whether emulsified or
         not, in  excess of one hundred (100) mg/1 or containing substances which may
         solidify or become viscous at temperatures between thirty-two (32) and one hundred
         fifty (150)0 p (0 and 65° C).

      (c) Any garbage that has not  been properly shredded.  The installation and operation
         of any  garbage grinder equipped with a motor of three-fourths (3/4) horsepower
         (0. 76 hp metric) or greater shall be subject to the  review and approval of the

      (d) Any waters or wastes containing strong acid iron pickling wastes,  or concentrated
         plating  solutions whether  neutralized or not.

                                                               The Model Sewer Ordinance
     (e) Any waters or wastes containing iron, chromium, copper,  zinc, and similar
         objectionable or toxic substances; or wastes exerting an excessive chlorine
         requirement, to such degree that any such material received in the composite
         sewage at the sewage treatment works exceeds the limits established by the
         (Superintendent) for such materials.

     (f) Any waters or wastes containing phenols or other taste- or odor-producing
         substances, in  such concentrations exceeding limits which may be established
         by the (Superintendent) as necessary, after treatment of the composite sewage,
         to meet the requirements of the State, Federal, or other public agencies of
         jurisdiction for such discharge to the receiving waters.

     (g) Any radioactive wastes or isotopes of such half-life or concentration as may
         exceed limits established by the (Superintendent) in  compliance with applicable
         State  or Federal regulations.

     (h) Any waters or wastes having a pH in excess of (9. 5).

     (i) Materials which exert or cause:

         (1) Unusual concentrations of inert  suspended solids (such as, but not limited
             to, Fullers earth, lime slurries, and  lime residues) or of dissolved solids
             (such as, but not limited to,  sodium chloride and sodium sulfate).

         (2) Excessive discoloration (such as,  but  not limited to,  dye wastes and
             vegetable tanning solutions).

         (3) Unusual BOD,  chemical oxygen  demand, or chlorine  requirements in
             such quantities as to constitute a significant load on the sewage treatment

         (4) Unusual volume of flow or concentration of wastes constituting "slugs" as
             defined herein.

     (j) Waters or wastes  containing substances which are not amenable to treatment
         or reduction by the sewage treatment processes employed, or are amenable to
         treatment only to such degree that the sewage treatment plant effluent cannot
         meet  the requirements of other agencies having jurisdiction over  discharge to
         the receiving waters.

Sec. 5.     If any waters or wastes are discharged,  or are proposed to be discharged to
     the public sewers,  which waters contain the substances  or possess the characteristics
     enumerated in Section 4 of this Article,  and which in the judgment of the (Superintendent),
     may have a deleterious effect upon the sewage works, processes, equipment,  or
     receiving waters, or which otherwise create a hazard to life  or constitute a public
     nuisance,  the (Superintendent) may:

     (a) Reject the wastes,

     (b) Require pretreatment to an acceptable condition for discharge to the public sewers,

     (c) Require control over the quantities and rates of discharge, and/or

The Model Sewer Ordinance
      (d)  Require payment to cover the added cost of handling and treating the wastes not
          covered by existing taxes or sewer charges under the provisions of Section 10
          of this article.

      If the (Superintendent) permits the pretreatment or equalization of waste flows, the
      design and installation of the plants and equipment shall be subject to the review and
      approval of the (Superintendent), and subject to the requirements of all applicable
      codes,  ordinances,  and laws.

Sec. 6.    Grease, oil, and sand interceptors shall be provided when, in the opinion of
      the  (Superintendent), they are necessary  for the proper handling of liquid wastes
      containing grease in excessive amounts,  or any flammable wastes, sand,  or other
      harmful ingredients; except that such interceptors shall not be required for private
      living quarters or dwelling units.  All interceptors shall be of a type and capacity
      approved by the (Superintendent), and shall be located as to be readily  and easily
      accessible for cleaning and inspection.

Sec. 7.    Where preliminary treatment or flow-equalizing facilities are provided for
      any waters  or wastes, they shall be maintained continuously in satisfactory and
      effective operation by the owner at his expense.

Sec. 8.    When required by the (Superintendent),  the owner of any property serviced by
      a building sewer carrying industrial wastes shall install a suitable control manhole
      together with such necessary meters and other appurtenances in the building sewer
      to facilitate observation,  sampling, and measurement of the wastes.  Such manhole,
      when required,  shall be accessibly and safely located,  and shall be constructed in
      accordance with plans approved by the (Superintendent).  The manhole  shall be
      installed by the owner at his expense, and shall be maintained by him so as to be
      safe and accessible at all times.

Sec. 9.    All measurements, tests,  and analyses of the characteristics of waters  and
      wastes to which reference is made in this ordinance shall be  determined in accordance
      with the latest edition of "Standard Methods for the Examination of Water and
      Wastewater, " published by the American Public Health Association, and shall be
      determined at the control manhole provided,  or upon suitable samples  taken at said
      control manhole.  In the event that no special manhole has been required, the  control
      manhole shall be  considered to be the nearest downstream manhole in  the public
      sewer to the point at which the building sewer is connected.  Sampling shall be
      carried out by customarily accepted methods to reflect the effect of constituents
      upon the sewage works and to determine the existence of hazards to life, limb, and
      property.  (The particular analyses involved will determine whether a  twenty-four
      (24) hour composite of all outfalls of a premise is appropriate or whether a grab
      sample or samples should be taken.  Normally, but not always BOD and suspended
      solids analyses are obtained from  24-hr, composites of all outfalls whereas pH's
      are determined from periodic  grab samples.)

Sec. 10.   No statement contained in this article shall be construed as preventing any
      special agreement or arrangement between the (city) and any industrial concern
      whereby an industrial waste of unusual strength or character may be accepted by
      the  (city) for treatment, subject to payment therefore,  by the industrial concern.

                                                                The Model Sewer Ordinance
                                        ARTICLE VI
                                   Protection from Damage

Sec, 1.     No unauthorized person  shall maliciously, willfully,  or negligently break,
      damage, destroy, uncover,  deface, or tamper with any structure,  appurtenance,
      or equipment which is a part of the sewage works.  Any person violating this
      provision shall be subject to immediate arrest under charge of disorderly conduct.
                                       ARTICLE VII
                              Powers and Authority of Inspectors

Sec. 1.     The (Superintendent) and other duly authorized employees of the (city) bearing
      proper credentials and identification shall be permitted to enter all properties for
      the purposes of inspection, observation,  measurement, sampling, and testing in
      accordance with the provisions of this ordinance.  The (Superintendent) or his
      representatives shall have no authority to inquire into any processes including
      metallurgical, chemical,  oil,  refining,  ceramic, paper, or other industries beyond
      that point having a direct bearing on the kind and source of discharge to the sewers
      or waterways or facilities for waste treatment.

Sec. 2.     While performing the necessary work on private properties referred to in
      Article VII, Section 1 above,  the (Superintendent) or duly authorized employees of
      the (city) shall observe all safety rules applicable to the premises established by
      the company and the company shall be held harmless for injury or death to the
      (city) employees and the (city) shall indemnify the company against loss or damage
      to its property by (city) employees and against liability claims and demands for
      personal injury or property damage asserted against the company and growing out
      of the gauging and sampling operation,  except as such may be caused by negligence
      or failure of the company  to maintain safe conditions as required in  Article V,
      Section 8.

Sec. 3.     The (Superintendent) and other duly authorized employees of the (city) bearing
      proper credentials and identification shall be permitted to enter all  private properties
      through which the (city) holds a duly negotiated easement for the purposes of, but not
      limited to, inspection,  observation, measurement,  sampling,  repair, and maintenance
      of any portion of the sewage works lying within said easement.  All  entry and sub-
      sequent work,  if any,  on said easement,  shall be done in full accordance with the
      terms of the duly negotiated easement pertaining to the private property involved.

The Model Sewer Ordinance
                                       ARTICLE VIII
Sec. 1.    Any person found to be violating any provision of this ordinance except
     Article VI shall be served by the (city) with written notice stating the nature of the
     violation and providing a reasonable time limit for the satisfactory correction
     thereof.  The offender shall, within the period of time stated in such notice,
     permanently cease all violations.

Sec. 2.    Any person who shall  continue any violation  beyond the time limit provided
     for in Article VIII, Section 1,  shall be guilty of a misdemeanor,  and on conviction
     thereof shall be fined in the amount not exceeding  (    ) dollars  for each violation.
     Each day in which any such  violation shall continue shall be deemed a separate

Sec. 3.    Any person violating any of the provisions of this ordinance shall become
     liable to the (city) for any expense, loss,  or damage occasioned  the (city) by
     reason of such violation.
                                       ARTICLE IX

Sec. 1.     All ordinances or parts of ordinances in conflict herewith are hereby repealed.

Sec. 2.     The invalidity of any section, clause, sentence,  or provision of this ordinance
      shall not affect the validity of any other part of this ordinance which can be given
      effect without such invalid part or parts.

                                        ARTICLE X

                                     Ordinance in Force

Sec. 1.     This ordinance shall be in full force and effect from and after its passage,
      approval,  recording,  and publication as provided by law.

Sec. 2.     Passed and adopted by the (Council) of the (city) of	
      State of	on the	day of (Month), (Year),  by the

      following vote:

      Ayes	:   namely	

      Nays	:   namely	

      Approved this	  day of	
      (Signed)	,  (Mayor)


      (Signed)	.  (Clerk)



A  The 1968 inventory of municipal waste
   facilities (1) estimated that 70 million
   people of 197 million population were
   connected to sewage  systems.  Some type
   of treatment was provided for 93% of the
   connected population of which 65.7% was
   of the secondary type.  During the six
   years since the 1962 inventory, secondary
   plant facilities had increased by 51% and
   the population served by 40%. The 1968
   report lists 12, 565 treatment plants for
   12,911 communities. Facilities are being
   provided at an increasing rate.  These
   plants stress secondary and/or advanced
   treatment operations as necessary to
   upgrade effluent quality.  The operations
   may be expected to increase in complexity
   as more people are connected and as
   treatment requirements increase.

B  The report on Manpower and Training
   needs (2) states "Still it is always the
   skill of the people  which transforms
   inanimate buildings and machines into
   productive devices."

   1 Operating personnel for existing treat-
     ment facilities perform remarkably well
     in many cases.  However, most existing
     facilities are not functioning as well as
     they could because of public indifference
     after the plant is built and because
     operating personnel commonly lack
     training adequate  for their responsibilities.

   2 The community is committed to debt
     service and default penalties.  Operating
     funds are not so protected.  Consequently,
     economy starts at the operating level.
     The facility cannot serve its intended
     function with a budget too low to attract
     and hold competent trained personnel
     with adequate funds for materials,
     maintenance and repair.
Operators are difficult to classify.  The
operator in charge is responsible for all
phases of the facility.  The shift operator
in a large plant may be responsible for a
limited assignment such as grit and trash
facilities.  The small plant operator has
a difficult assignment because he may
have little backup  support, must perform
all functions and frequently has  had little
training for it.  Overall functions in
operation include:

1  Inspection, housekeeping, meter reading,
   adjustments, lubrication, repair,
   reports of events and calculations
   involving performance and costs.

2  Control of physical operations such as
   screening,  grinding, pumping,
   clarification, aeration, filtration,
   drying, etc.

3  Control of biological conditions
   favoring desired performance for
   aerobic, anaerobic or facultative
   working organisms under varying
   loading and conditions.

4  Control of chemical processes such as
   neutralization coagulation oxidation

5  Perform sampling and testing operations
   indicating work done or remaining to
   be done.

6  Serve as an  information source for
   public officials, lay groups,  suppliers,
   consultants on specific facility problems.

Technology is available today to clean our
environment if we accept performance as
the main criteria rather than cheapness.
Institutions are available for planning,
construction, and  operation. Facilities
are in short supply.   Trained qualified
 SE.TT. 11.7.71

 Training for Wastewater Treatment Plant Operators
   people are in shorter supply at all levels
   of environmental technology.

E Environmental technology involves many
   functional groups such as planning survey,
   management,  consultation,  design,  supply,
   construction,  maintenance and operation.

   1  Training in the last group has tended to
      be of the unplanned hit or miss category.
      On-the-job training depends on the
      co-workers attitude and has tended to
      be spotty and slow without planned
      training with rotated assignments.

   2  Training must be suited for student
      capability and background.  The
      specialist may be trained by abstracts
      and theory,  the intermediate level
      operator by cause and effect examples,
      entry level personnel may not even
      know the terms for questioning.

   3  Operator training stress is increasing
      toward defining a job or task,  designing
      instruction for the task and student
      background, and training personnel to
      fit the description.  To work effectively,
      the definer,  the instructor,  and the
      student must communicate in common

   4  Participant diversity in a given course    ,
      should not be so large that the entry
      level student doesn't know the instructor's
      language, the intermediate level student
      can digest half of it and the advanced
      student is bored from the start.  Some
      diversity is beneficial so that students
      participate as instructors on familiar

F  Each individual seeking to improve himself
   must make do-it-yourself training a way
   of life.  Alertness during day to day con-
   tacts is the most valuable learning asset.
   Daily contacts include:

   1   Trial and error or cause and effect
      relationships. This is commonly called

   2   Talk with available supervisors  -
      interest in their problems is likely to
      reveal an amazing return interest.
   3  Communicate with co-workers,  on site
      and nearby. It's likely that each has a
      different response to a given situation;
      each has a "bit" to contribute.

   4  Talk with local officials, manufacturers
      or supplier representatives, laymen,
      teachers - anyone who may be,  or can
      be interested in wastewater treatment

   5  Each facility have some training plan  -
      buddy system,  counselor,  rotating
      assignment, question and answer,
      topic development,  reading program,
      on or off-site courses,  practice
      sessions, or combinations  thereof.
      Encourage this by active participation
      in them during  group sessions or
      individual contact.

   6  Become active  in local, state and
      national association affairs in the
      field.   Attend meetings where possible.
      Discuss personal impressions with
      others.  Develop contacts with other
      operators, regulatory officials,
      instructors, industrial, consulting,
      and lay groups.

   7  Develop ability to read with a purpose;
      use this ability regularly.  Expand the
      plant and home library with periodicals,
      bulletins, texts, references, pertinent
      news items or releases. Include at
      least one good handbook and a
      dictionary.  Set up a system of storage
      so that a given  item  can be found when
      you need it. Use the public, school,
      or trade library. Valuable source
      materials are available on  a no charge
      basis from government agencies,  schools,
      associations, and suppliers.

G  It is necessary to  remain unsatisfied with
   any given  level of ability.  It is not possible
   to maintain a static capability level.  Any
   individual must improve or lose what is
   not used.  Use the seven senses diligently -
   i.e. seeing, hearing, feeling,  smelling,
   taste, common, and horse. Partial
   compensation is possible if you cannot use
   one or more of these; there is no com-
   pensation  if you do not use available senses.

                                         Training for Wastewater Treatment Plant Operators
    Enthusiasm is catching.  It may not be
    possible to achieve all that enthusiasm
    attempted but no group  action persists
    without enthusiasm.

 H  Training to upgrade entry and inter-
    mediate level operating personnel to
    increase the number of qualified wastewater
    treatment plant operators is the major
    interest of this outline.  Graduate and
    post graduate degree training,  military
    inservice training with  operating or
    environmental stress are very important
    to total environmental upgrading but may
    not be available for  civilian personnel of
    the interest level intended.  Time and
    space does not permit a complete listing.
    Selected examples are used to indicate
    current stress in training development.

 A It is estimated that our youngsters have
   had about 10, 000 hrs. of TV time prior
   to primary school training.  Activities in
   class, projects,  educational TV, films,
   community, and lay groups increase
   awareness of environmental problems.
   Environmental consciousness may be
   spotty but it's popular to be an ecology
   "expert".  Some  of it is likely to register.

 B Secondary schools are the terminal
   academic level for a large segment of the
   population.  Changes have been and are
   being made to adapt curricula to socio-
   economic realities likely to be encountered.
   Environmental training is part of this.

   1  More and more high schools are
      expanding present vocational training
      or are developing new programs at the
      junior and senior levels.

   2  The Curriculum Activities Guide for
      Water Pollution Control and Environ-
      mental Studies prepared by The Tilton
      School, Tilton, NH (FWQA Grant
      1TT1-WP-41-01) is another example
      of environmental activities at the
      secondary school level.
3  Many other forms of environmental
   emphasis are fostered by visual aids
   interests,  commercial developers,
   text book publishers,  trade associations,
   conservation or public interest lay
   groups and individual instructors or
   their associations.

Post High School Technician Training:
Vocational training for the  high school
graduate has  increased very rapidly in
the past few years.  Less than 20
vocational schools offered  environmental
training courses prior to 1968.  A partial
listing from the National Sanitation
Foundation,  Ann Arbor,  MI, dated
November 1970 included 70 post-secondary
schools with environmental training in
23 states.  Most of these are based upon
two year curricula.  It is not known how
many of these are engaged in courses
specific for water and wastewater.

1  These  courses are intended to train
   technicians for job entry level
   capabilities in environmental operations.

2  The community college  or vocational
   school is favorable for development
   of special courses for local development.

   a  The instructor staff may be a blend
      of professional teachers and working

   b  The course may include on-the-job
      training at appropriate points in the

   c  Liaison of academic  and working
      knowledge provides a center of
      information on specific questions
      from local operators.

   d  Special topic seminars or short
      courses may be developed for evening
      or daytime sessions.

University courses traditionally have
stressed theory and abstracts for planning,
management, consulting construction,
design regulation and related specialties.

Training for Wastewater Treatment Plant Operators
   Relatively small percentages of degree
   students have entered operations except
   in large or complex treatment facilities.

   1 Undergraduate curricula have changed
     or are changing toward an interdisciplinary
     approach and process dynamics.

   2 Post graduate curricula are tending to
     be adapted more closely to student
     program interest than to rigid course

   3 Courses tend to be more closely related
     to total environmental interest than to
     an isolated segment of it.

   4 The Association of Professors of
     Sanitary Engineering have instituted
     several activities to encourage better
     student coordination with procedures
     outside of the university.

E  University non-resident training is
   unusually varied,  such as:

   1 Universities have been a source  of
     materials, site of,  and have provided
     instructors for many short term
     seminars, courses, or other training
     in conjunction with federal,  state,
     industrial or professional  groups.

   2 The Programmed Instruction Series
     for Water Pollution Control developed
     at the University of Michigan Center
     for Research and Learning by Drs. K.H.
     Mancy and L. A.  Pursglove is a relatively
     new approach to self-study for operators.

   3 The Correspondence Course developed
     at Clemson University, Clemson, SC
     for South Carolina operator training,
     2nd Ed.,  Dr.  John H.  Austin, Editor,
     is another form of operator instruction.

   4 The Seminar on Educational Systems for
     Operators of Water Pollutional Control
     Facilities sponsored by the U.S.  Dept.
     of Interior,  FWPCA and Clemson
     University at Atlanta,  GA,  November
     1969 was important for orientation of
     past, present and future operator
     training  considerations.
    5  Sacramento State University,
       Sacramento, CA, Dr. Kenneth D.
       Kerri, Director, has prepared a
       correspondence course for operators
       that has input from both educators
       and operators.   This project currently
       is in the finishing stages for printing.

    6  Books, reports on special investigations,
       manuals, etc. have been prepared on
       special topics under sponsorship of
       contracting agencies.

 A Advancement in the state of the art in all
    phases of water pollution control is the
    major charter commitment of the WPCF.

    1  Publication of articles relating to
       planning, design, administration,
       research, and facilities operation,
       municipal and industrial,  have been
       continued in the Federation Journal
       since its inception in 1928.

    2  The Manual  of Practice Series have
       been prepared by member committees
       to reflect established practice and
       recommendations for special topics.
       MOP-1 considers safety practice,
       MOP-20  considers sludge dewatering.
       These  are updated at intervals depending
       upon changes in stress or state of the
       art and upon committee activities.

    3  The WPCF acts in a liaison capacity
       among federal,interstate,  state,
       university,  industrial,  and local
       agencies. It acts as an information
       source for agencies or individuals,
       professional associations  and lay
       groups.  As  a professional association,
       it provides recommendations pertaining
       to proposed actions with an environmental

       a  Model legislation on matters related
          to water pollution control organization,
          enforcement, certification and related
          regulations have been devised as
          guidelines for consideration by
          governing bodies and interested groups.

                                         Training for Wastewater Treatment Plant Operators
     b  Suggested plans for organizing
        functional groups for implementation
        of WPC are available for use by
        public or corporate agencies.

     c  The WPCF serves with inter-
        professional associations such as
        the APHA, ASCE; AWWA and others
        on matters related to common
        interests such as design, standard
        methods, terminology.

   4 The organization sponsors national,
     state,  regional and local meetings,
     seminars or discussions of common
     interest  to improve individual contacts
     and  capabilities for working in a team

B  Interest in operator status training and
   performance upgrading is a continuing
   objective.  Recent trends have resulted
   in increased stress toward upgrading
   apprentice personnel and continued
   development of the operator who has not
   had the benefit of special training.

   1 Mandatory certification of operator
     personnel has been a long term goal
     to increase status of personnel,
     continuity and performance of existing
     treatment operations. Uniform
     certification has not been realized but
     they have become more consistent and
     comprehensive. As of January 1,  1971,
     27 states had mandatory certification,
     20 had voluntary programs and 3 had no
     formal program.  Mandatory certification
     is pending in several states.

   2 Training materials and programs have
     been formulated for two courses by
     committees of the WPCF to guide
     state,  local, and other groups to provide
     improved training to upgrade personnel
     for operational capability.   Strong
     emphasis on safety training earned a
     national  safety award 1970.

   3 The  Personnel Advancement Committee
     assembles data on existing certification,
     personnel training practice and provides
     guidance pertinent to new or developing
C  A Workshop on Operator Training held at
   the Dallas meeting of the WPCF,
   October 1969,  led to a new program
   emphasizing operator training needs and
   problems.  Project "Manforce" has
   resulted from this  effort.  Manforce has
   assumed certain obligations of other
   activities of the WPCF,  and parallels
   certain federal and state programs.  It
   has a new organizational structure and
   limited staffing to date but certain factors
   are becoming evident to foster improved
   operator interest.

   1 The "Deeds and Data" section of
     Highlights" is a new publication now
     appearing monthly that is written
     specifically for  operators.  It includes
     a sounding board for  operators,
     information on operating safety,  training
     questions, discussions,  definitions and

   2 A new committee for operator  certification
     has been formed,  Terry M. Regan,
     Chairman, Kentucky  Certification
     Board, to enhance certification

   3 The Black and Veatch report on
     operator and specialist job descriptions
     and staffing for  wastewater treatment
     facilities has been reviewed by
     Personnel Advancement and Manforce
     Committees.  Intent is to assist job
     classification and recommended
     staffing requirements for operations.

   4 A new staff member has been employed
     as Director of Education and Training.

   5 Top priority has been assigned to:

     a  Uniform certification

     b  Manpower needs and salary

     c  Recruitment  and retention of
        capable operating personnel

 Training for Wastewater Treatment Plant Operators

 Primary responsibilities for water quality,
 planning,  development and implementation
 are state functions.  Local agencies work
 within the state framework and regulations
 on front line functions of treatment technology.

 A  Certification authority and programs vary
    from state to state.  An effective certification
    program requires a good entry level
    training program.  This must be backed
    by effective recruitment,  meaningful
    training and salaries  adequate to hold
    trained personnel.

    1  The common 1 to 5 day intensive
       training course at  one year intervals
       at central locations continues to be
       useful for upgrading intermediate and
       advanced operator personnel.  These
       groups have better contacts, usually
       can participate in monthly association
       or other meetings  and have a better
       chance to continue their education by
       means not available to  entry level

    2  Entry level personnel usually require
       many more hours of training in
       terminology, equipment and task
       identification,  practice, and basic
       arithmetical manipulations.  This
       generally means that training must be
       brought to the recruit to minimize
       travel restrictions.

    3  The states have power  to certify and to
       enforce.  Sometimes home rule or other
       limitations  make it difficult to implement
       adequate staffing and budget allowances
       to attract and hold competent local
       personnel on a state-wide basis.  Public
       relations and certification help.

 B  Entry level training has been expanded and
    is being offered at more sites.  More
    expansion is needed.  Instructors capable
    of productive training in treatment operation
    are difficult to  locate - they generally must
    be  developed and trained to present that
    which the apprentice needs in a manner
    understood by him.
       The plant manager is becoming more
       conscious of personnel training
       responsibility.  He may delegate
       training responsibility to others, but
       he is responsible for results.

       Community colleges are becoming
       more numerous and more active as
       environmental training centers.

       The public expects more; hopefully,
       they can be educated to the fact that
       environmental quality is not a free-
       ride.  Service charges and other
       activities are moving in the direction
       of more realistic funding.

       Local high school vocational training
       is improving.  Use of the facilities for
       mixed academic and on-the-job training
       is expanding.

       An increasing number of States have
       full time training directors, committees,
       and instructors for local training.

       a  Special training committees have
         been formed to contract for, receive
         money,  and handle disbursements
         for training materials such  as the
         Texas, California,  New York,
         South Carolina and the Ohio training

       b  Special state personnel have been
         designated for on site visits or
         group meetings for local training

       c  Support may be arranged for
         supplementary payment for  local
         operator time devoted to training

       d  An increasing number of courses
         are becoming available where the
         participant receives combined class
         and on the job training (OJT).

 A  The Federal Role in wastewater operator
    personnel training commonly is an

                                        Training for Wastewater Treatment Plant Operators
interagency function among federal,  state
or local governments,  universities,
corporations,  associations or other
contracting bodies.  Financial support
may be partial or complete through con-
tracts grants or projects.

1  Objectives  may include programs for
   staffing, curricula, manuals,  visuals,
   lesson plans etc. to be used by others
   in  class, home  study, correspondence
   or other personnel training.

2  Financial support may be partial or
   complete for programs including
   instruction, materials,  and administration
   by state or local agencies.

3  Joint federal, state or local input as
   agreed upon to fit the situation is

4  Direct federal training including funding,
   administration,  supervision, instruction
   materials with or without student support
   may be provided.

The office  of Water Programs, EPA
through the Division of Manpower and
Training, State and Local Manpower
Development Branch anticipates training
approximately 2600 individuals in the next
fiscal year.  These programs are funded
through the Department of  Labor and the
Department of Health, Education and
Welfare as follows:

1  Institutional Training Program

   Conducted at  Community Colleges or
   Vocational Training Schools in nine
   states are presently planned (NY, MD,
   GA, OH, CA, MO, IA,  TX, and ID).
   Two 22  week courses for 20 participants
   each include 440 hours of class
   instruction and an equal amount of time
   for practical experience in plant treat-
   ment.  Approximately 360 enrollees will
   be trained for $734, 000 with trainee
   allowance of $400, 000.  Instructors,
   supplies, equipment,  administration,
   supervision and placement  costs are
2  The Transition Training Program will
   be conducted at military installations
   with or near treatment plants and
   academic institutions (five locations
   now).  Trainees at army bases will
   receive 240 hours of training,  640 hours
   at a marine base.  Enrollees will be
   trained in groups of  12 including
   servicemen in their  last 6 months of
   duty.  Program cost is  $245, 000  for
   instructors, supplies, equipment,
   supervision and placement of successful
   trainees.  Students may qualify for
   Veterans Administration approved on the
   (OJT) additional training.

3  The coupled OJT National Projects
   will be conducted in  27 states with a
   total of 50 project sites. Each
   subcontractor is a unit of the state
   government, a municipality, a waste
   treatment district or community
   college.  70% of enrollees will be in
   skill improvement training,  30%  at
   entry level. A total of  1000 individuals
   will be trained at a cost of $1, 260, 000.
   Approximately $300, 000 will be used
   for instructors, supplies, equipment,
   administration and supervision.

4  The Public Careers  Program is
   presently underway in VA,  SC, TX
   (2 locations) WI and  the Virgin Islands.
   Sponsors are charged with finding
   existing vacant positions and providing
   training at  entry level as well as
   upgrading.   Approximately 400 new
   and 500 upgraded individuals will be
   trained at a cost of $1, 500, 000 of which
   $1, 200, 000 will be for instruction,
   equipment, supplies and supportive

The  previous  section represents a rapidly
expanding ongoing program of federal,
state and local activities.

Training for Wastewater Treatment Plant Operators
      Completed MDTA projects supported
      by the Depts. of Labor, HEW, Interior,
      and cooperating agencies in  Indiana,
      Ohio,  Kentucky and West Virginia
      during FY 70 include:
IN  6 projects
OH 1 project
KY 2 projects
WV 1 project
4 cities  131 individuals trained
1 city     19 individuals trained
2 cities   60 individuals trained
1 city     32 individuals trained
   2  These projects were similar to that
      described in V, B3.  They were in
      addition to established state and local
      operator training for entry level
      personnel and upgrading existing
      operator personnel.  Similar training
      has been given in many states besides
      the examples cited.  New  mandatory
      certification programs and higher
      treatment requirements have dictated
      many new or  greatly expanded personnel
      training activities.  Other new training
      facilities are being developed.

   Federal support of training through the
   Training Grants Branch of the Division
   of Manpower and Training usually is in
   the form of Grants, Contracts, or Project
   funding to some  delegated agency such as
   universities, professional associations,

   State or Local Agencies

   1  Among others these include previously
      described projects such as III B C D E,
      IV A. 2, C.3.

   2  Training Grants for academic
      institutions may include student and
      project support.

   3  Community colleges and other training
      institutions are encouraged by contract.

   The Direct Training Branch of the Division
   of Manpower and Training engages in short
   term intensive training courses for planning,
   supervisory, technical and instructor
   These are located in Ada, OK,  Athens, GA,
   Cincinnati, OH (National Training Center),
   Corvallis, OR, Edison, NJ and Fairbanks,

   Training support  for operator personnel

   1  Consultation, source information,
      visiting lecturers, topic background
      materials or lesson plans, and
      coordinating assistance for local

   2  Courses specifically directed toward
      operator  instructor personnel on
      technical background and instruction
      methodology are offered.

   3  A catalog of tape/slide audio visual
      presentations has been developed and
      is expanding for  circulation to state
      or local training groups as a nucleus
      for special topic presentation-
      discussion sessions.

   4  Study  carrels for self-instruction on
      basic  information are being developed.

   5  Administrative and technical guidance
      for correspondence training is nearing

F  Technology Transfer Program of the EPA

   1  This effort is not specifically operator
      training but plant operation is  not
      possible without  versatile and operable
      plants in  line with need.  This program
      is aimed  for those who provide the
      facilities.  The Technology Transfer
      Program of the EPA recognizes that
      advanced technology will not be used
      unless three groups apply it.  Specific
      parts  of the program are directed toward:
      1) the  design engineer; 2) the administrator;
      3) the  public information group.
      Technology Transfer was announced as a
      top priority item of the EPA by
      Commissioner Dominick at the 43rd
      Annual Conference WPCF at Boston,
      MA  in October 1970.

                                   Training for Wastewater Treatment Plant Operators
a  The Headquarters Advisory Board
   consists of three  Regional Directors,
   two members of the Office of Water
   Program and one  each from the
   Advanced Waste Treatment Laboratory
   and Facilities Construction.

b  A Headquarters Working Committee
   includes two representatives  from
   Research and Development, one
   each from Facilities Construction,
   Manpower Training and Public Relations.

c  Each Region has a Working Committee.

The program evolved from Seminars
and Workshop Sessions of the AWTR
group that listed 3464 attendees  from
administrative, consulting,  design,
technical personnel,  professional and
lay personnel in 11 major cities  from
July 1,  1968 to February 1971.

The first seminar/workshop under the
new program other than for organization
and development purposes was held at
Chapel Hill, NC February 8-9,  1971.
One was held in Cleveland, OH in
April 1971, one in Boston in May and
another at Charlottesville,  VA in
June 1971.

The problem is that plants tend to be
designed as they have been designed.
The Technology Transfer Program is
intended to transmit  sufficient
technology to design  and  construction
engineers so that the most efficient
treatment facilities can be designed
and constructed at favorable cost/
benefit ratios.  Plans as of March 1971

a  Program for contributing engineers
   (By January 1974)

   1)  36 seminar/workshops for con-
      tributing engineers distributed
      among all regions.

   2)  National meetings and conference
      information, exhibits, talks
      (4 national meetings).
      3) Available information at local
        meetings (75 local meetings)

      4) Exploit demonstrations of new
        technology, visits,  visuals and

      5) Issue 8 design manuals,  12
        newsletters and several technical

      6) Provide current operation and
        maintenance procedures to
        engineers in liaison with the
        Manpower and Training Program.

   b  Program for administrators
      (By January 1974)

      1) Conduct 32 administrative work-
        shops (all regions).

      2) Publish 9 State of the Technology
        Articles in non-technology journals.

      3) Conduct an information program
        for administrators and public
        officials - semi-technical

   c  Program for public information
      groups (January 1974)

      1) Provide current information to
        local action groups leaflets  -
        newsletters - lectures - tours.

      2) Initiate national and local public
        information campaign using all
        media - TV documentaries,
        public displays.

      3) Initiate national recognition
        program for successful transfer
        and use of new technology -
        awards to waste treatment plants.

Each Regional Office of the EPA has a
Manpower and Training Coordinator  for
their area.

 Training for Wastewater Treatment Plant Operators

 A Operator personnel training is a function
    of many interrelated organizations such
    as government agencies, professional,
    industrial,  manufacturing, supply,
    educational institutions and all levels of
    personnel within the organizations.   To
    work, personnel training is a personal
    responsibility of each individual in the

 B Personnel training necessarily must be
    adapted for communication among various
    levels of responsibility, job descriptions
    and pre-existing capabilities  of the trainee.

    1  Entry level personnel require a knowledge
       of what is expected  from their assigned
       tasks, language training,  identification
       of tools and processes  and how to do it
       practice among assigned tasks.

    2  Intermediate level personnel require
       development of cause and  effect
       relationships,  expansion of task
       oriented capabilities and continuing
       development in how  each bit fits into
       the whole.

    3  Advanced level personnel  require
       emphasis on integration of effort to
       improve performance with available
       or obtainable people, equipment and

 C Motivation is the basis for growth of
    personnel capabilities.  Recognition  of
    gain as a result of effort expended may
    take the form of:

    1  Monetary reward

    2  Public recognition

    3  Increased and varied interests

    4  Greater responsibilities

    5  Improved working conditions

    6  Status improvement from a standpoint
       of job security, choice  of assignment,
       location, etc.
   7  A feeling of doing something important. <

   Training is a primary responsibility of
   line operating personnel and their
   immediate supervision.  Planned training
   is essential for continued development of
   personnel capabilities.  Class work
   hastens development but applications
   make it meaningful.

Many individuals,  federal, state and local
contributed information included in this
outline.  Special thanks are due to Daniel D.
Daniels, Chief,  State Training Activities,
EPA, Joseph D. Lipps, Training Coordinator
of the previous Ohio Basin District now part
of EPA,  Region V, Robert A. Canham Exec.
Sec. WPCF,  Sam  L.  Warrington,  Chairman,
Personnel Advancement Committee, WPCF
andF.M. Middleton,  Director, Advanced
Waste Treatment Research Laboratory,  EPA.

Additional Reading:

1  Municipal Waste Facilities in the United
      States.  U.S. Dept. of the Interior.
      FWQA,  1968.

2  Senate Document No. 49,  90th Congress
      Manpower and Training Needs in Water
      Pollution Control,  1967.

3  Educational Systems for Operators of
      Water Pollution Control Facilities,
      Clemson University and Dept. of the
      Interior.  November 1969, Atlanta,  GA.

4  Robert F. Mager and Kenneth M. Beach,  Jr.,
      Developing Vocational Objectives.
      Fearon Publishers,  Palo Alto, CA.
This outline was prepared by F. J. Ludzack,
Chemist, National Training Center,  OWP,
EPA, Cincinnati, OH 45226.

Municipality	Date	Rated by	Score
(A)   Degree of treatment and Effluent Quality based on Suspended Solids
      and BOD removal during lowest flow month of previous year.  (Max. 25)

      I.  For plants employing only Primary Treatment (with or without
         chemical precipitation)

         1.  4 point for each percentage of removal above 40 (BOD)-(Max. 5)

         2.  ipoint for each percentage of removal above 55 (Suspended
            Solids)                                              (Max. 5)

         3.  ipoint for each mg/1 of BOD in effluent less than 120   (Max. 5)

         4.  i point for each mg/1 of Suspended Solids in effluent
            less  than 90                                         (Max. 5)
                             (Max. Total 20          )
     II.  For Secondary Treatment Plants

         1.  ?point for each percentage of removal above 75 (BOD) (Max. 5)

         2.  4 point for each percentage of removal above 75
            (Suspended Solids)                                   (Max. 5)

         3.  i point for each mg/1 of BOD in effluent less than 30    (Max. 5)

         4.  ipoint for each mg/1 of Suspended Solids in effluent
            less than 30

         5.  Minimum removal of BOD for any month  in previous
            year add 2 point for each percentage of removal in
            excess of 80                                         (Max. 5)
                             (Max. Total 25        )
(B)   Amount of Bypassing (untreated sewage) taking place either at the plant
      or on the system. (Max. 10)

        1.  Occurs on separate occasions on at least nine months
            of the year                                           (0)

        2.  Occurs on separate occasions on at least six  months
            of the year                                           (2)

        3.  Occurs on separate occasions on at least three months
            of the year                                           (4)
SE. MAN. 10.9.69

Evaluation of Wastewater Treatment Programs

         4.  Does not occur at any time                            (6)

         5.  Does not occur and the flow into the plant does
            not exceed twice the design  capacity of the entire
            plant                                                 (10)        	
                   (MAXIMUM MONTHLY FLOW)

(C)   Competency of operators based on certification (determined
      by the lowest  coverage of any one-month period during
      previous years)  (Max. 10)                                             	

         1.  Neither certified operator nor technical supervisor
            available                                             (0)         	

         2.  Technical supervisor available - no other certified
            personnel available                                   (2)

         3.  Technical supervision with one or more full time
            man certified                                         (4)         	

         4.  Certified operator in charge meeting the
            certification requirements of the plant                 (8)         	

            a.  If plant serving less than 5, 000 PE, and under
                responsible charge of properly certified operator   (10)        	

         5.  Properly certified operator in charge plus certified
            operators on duty with total certification equal to
            or exceeding required certification                    (10)        	

(D)   Capacity of plant based on minimum approved design of any
      major plant component.   Flow based on annual monthly
      averages of preceeding year. (Max. 10)                                 	

         1.  Annual monthly average flow exceeds plant capacity     (0)         	

         2.  Annual monthly average flow 90  - 100% plant capacity
            but detail plans not approved                          (1)         	

         3.  Annual monthly average flow 90  - 100% plant capacity
            and detail plans approved                             (2)         	

         4.  Annual monthly average flow 80  - 90% plant capacity    (4)         	

         5.  Annual monthly average flow 80  - 90% plant capacity
            and general plans approved for plant expansion and
            detail plans being prepared                            (5)         	

         6.  Annual monthly average flow less than 80% of plant
            capacity                                              (5)         	
                             Add to Above

            la. Maximum monthly average  flow exceeds 1.5 X
                design capacity                                  (0)         	

                                          Evaluation of Wastewater Treatment Programs
            2a.  Maximum monthly average flow less than 1.5
                 design capacity
            3a.  Maximum monthly average flow less than design
                 capacity                                          (5)
(E)   Condition of the receiving stream based on visual evidence of
      pollution at any critical time during the year and also based on
      stream sampling done by the operator,  (minimum monthly
      average for previous year)  (Max. 20)
Visible evidence of septic conditions, formation of
sludge banks,  emanation of odors,  or unsightly amount
of substances attributable to sewage discharges
Visible evidence of gray filamentaceous bottom growths
on the stream bed below the outfall or evidence in plant
records of a D. O. of less than 5 but greater than 2 mg/1
in the receiving stream                                (5)

Visible evidence of turbid conditions in ponded areas of
the receiving stream or  slight evidence of sewage
residual along the stream banks and plant reports
indicate D. O.  greater than 5 mg/1                      (10)

No visible evidence of plant discharge or stream
pollution at  the time of the review and plant reports
indicate D. O.  greater than 5 mg/1 in the receiving
stream                                               (15)

No visible evidence of plant discharge or stream
pollution at  the time of the review and plant reports
indicate D. O.  greater than 5 mg/1 in the receiving
stream. Also, adequate disinfection of the effluent.     (20)

For plants discharging to large  rivers or lakes where
evaluation of the effect of a single plant on the receiving
waters  is  difficult, points given shall be based on the
degree to  which the plant meets effluent standards
established  for the stream in  question.
      Receiving Water
      Established Effluent Standards:

      	% BOD Removal

                                    Months Reqd.  Months Met
   Months met X 20
   Months reqd.
                                                                  (Max. 20)

Evaluation of Wastewater Treatment Programs
(F)   Control of all sources of pollution within the municipality
      (Max. 15  Minimum 0)

         1.  Evidence of significant quantities of improperly
            treated sewage or industrial wastes being discharged
            to streams or storm sewers within the municipality.
            Exclude wastes from industries and other separate
            sources under permit.                                 (0)

         2.  No evidence of improperly treated waste discharges
            but individual systems utilized for over 10% of the
            municipal population                                   (5)

         3.  No evidence of improperly treated waste discharges
            but individual systems utilized by 3 to 10% of the
            municipal population                                   (10)

         4.  No evidence of improperly treated waste discharges
            and less than 3% of the municipal population served by
            individual systems                                     (15)

         5.  All sources of wastes connected to the sanitary sewer   (15)

            From the  total noted above deduct the following:

            2 X the %  of homes equipped with questionable treatment
            devices (septic tanks only or less) discharging to storm
            sewers or waters of the State.  If the system has not
            been checked or upgraded by the  local health department
            in ten years, it is considered "questionable".
                                                       Points  Deducted

            2 X the %  of industries (by number) served with indi-
            vidual systems not  under W.P.C.B. permit or a valid
            local  surveillance program
                                                       Points  Deducted
            Total for  F Category  - Max.  15 - Minimum 0
(G)   Appearance of the plant and the plant grounds. (Max.  10)

         1.  Plant grounds and plant operation not esthetically
            attractive                                             (0)

         2.  Plant grounds and plant operation are esthetically
            attractive                                             (10)
This outline was prepared by R. J. Carlton, Assistant District Engineer, Ohio State Board
of Health, Dayton, OH 45402.

This is a selected list containing the key
ideas of terms likely to be encountered
in treatment technology.
For more scientific definitions or unlisted
terms, consult the list of references at the
end of the glossary.
ABSORPTION  -  The taking up of one sub-
      stance into the body of another .

ACRE FOOT - A volume term referring
      to that amount of liquid 1 acre in area
      and a depth of 1 foot.  43, 560 cu.ft.

ACID  - Most commonly refers to a large
      class of chemicals having a sour taste
      in water, ability to dissolve certain
      metals, bases or alkalies to form salts
      and to turn certain acid-base indicators
      to their acid form.  Characterized by
      the  hydrated H"*" ion.

ACTIVATED SLUDGE - A process  used for
      purification and stabilization of waste-
      waters by mixing of the solids concen-
      trate from  previous contact with raw
      or settled wastewaters under turbulent
      oxygenating conditions for sufficient
      time to permit transfer of nutrients
      to the solids phase, partial biodegra-
      dation and clarification of the water
      before discharge.

ADSORPTION  -  The taking up of one sub-
      stance upon the surface of or interface
      zone of another substance.

      Renovation of used water by biological,
      chemical or physical methods  that are
      applied to upgrade water quality for
      specific reuse requirements.  May
      include more efficient cleanup of a
      general nature or the removal of com-
      ponents that are inefficiently removed
      by conventional treatment processes.

AERATION - The operation of adding oxygen
      to,  removing volatile constituents from,
      or mixing a liquid by intimate  contact
      with air.

DERATION PERIOD - A theoretical time
      usually expressed in hours equal to
      the  volume of the  tank divided  by the
      volumetric rate of flow.

AEROBIC - A  condition characterized by
      an excess of dissolved  oxygen  in the
      aquatic environment.
 AEROBIC BACTERIA  -  Organisms that
       require dissolved oxygen in the
       aquatic environment to enable them
       to metabolize or to grow.

 AGGLOMERATION - An action by which
       small particles gather into larger
       particles that are more readily
       separated from the liquid by sedi-
       mentation or other means.   May be
       the result of biological, chemical
       or physical factors.

 AIR  LIFT - A pump consisting of a vertical
       pipe immersed in a liquid into which
       air is mixed to reduce specific gravity
       of the air-liquid  mixture.   The net
       effect is to raise the liquid level in
       the discharge pipe.

 ALGAE - Primitive plants,  one  or many
       celled, usually aquatic and capable
       of growth on mineral materials via
       energy from the  sun and the green
       coloring material, chlorophyll.
       Generally considered as the primary
       source of food for  all other organisms.

 ALKALINITY - A term  used to represent
       the sum of the effects opposite in
       reaction to acids in water.   Usually
       due to carbonates, bicarbonates and
       hydroxides;  also including borates,
       silicates and phosphates.

       A means of determining residual
       available chlorine with phenyl arsene
       oxide (PAO) titration using current
       response as an indicator of equiva-
       lence.  For  wastewater, the PAO
       preferably is used in excess with
       iodine backtitration.

 ANAEROBIC -  A  condition in which dis-
       solved oxygen is not detectable in
       the aquatic environment.  Commonly
       characterized by the formation of
       reduced sulfur compounds from the
       use of bound oxygen from sulfates
       as an hydrogen acceptor.
AT. 2. 8. 69

Glossary - Wastewater Treatment Technology
      can metabolize and grow in the absence
      of dissolved oxygen.  Their oxygen
      supply is obtained from the bound oxy-
      gen such as in sulfates, carbonates,
      or other oxygen-containing compounds.

ANION  -  A negatively charged ion in water
      solution.  May be a single element or
      a combination of elements, such as
      the  Cl" ion in a water solution of NaCl
      (common table salt) or SO4= ion in a
      sulfuric acid solution.

ASSESSMENT - A legal financial obligation
      of the property owner in an irrigation,
      water, drainage or sanitary district,
      created for the purpose of financing
      the  construction and operation of
      facilities required to protect and en-
      hance public benefit within the district.

ATTACHED GROWTH  - Plant or animal
      growth that tends to seek a solid sur-
      face for a point of attachment from
      which to grow, in contrast with free-
      swimming or suspended organisms.

ATOM -  An extremely  small unit or particle
      of an element consisting of a positively
      charged nucleus and one or more
      negatively charged electrons.  Atoms
      of different elements are different in
      mass  and the number of electrons.
      Electrons may be located in the nucleus
      or externally.  The external electrons
      determine chemical combining power.

ATOMIC WEIGHT - A relative mass of an
      atom of an element compared to
      carbon-12.  May be expressed in
      grams (g), pounds or other consistent
      weight units when used for process

      Generally refers to that part of the
      chlorine that will  react with ortho
      tolidine or amperometric tests and
      exhibits significant germicidal activity.

ASSOCIATION) - An organization composed
      of individuals engaged in research,
      design, operation and control in the
      advancement of knowledge related
      to potable water supply
BACTERIA  -  Primitive organisms having
      some of the features of plants and
      animals. Generally included among
      the fungi.  Usually do not contain
      chlorophyll,  hence commonly require
      preformed organic nutrients among
      their foods.  May exist as single cells,
      groups,  filaments, or colonies.

BACTERIACIDE - Any component that
      will kill or destroy bacteria.

BACTERIOSTATIC - A condition  during
      which the normal metabolic  functions
      of bacteria are arrested until favor-
      able conditions are restored.

BACTERIOLOGY -  See Microbiology.

BAFFLE  -  A deflector or check such as
      a vane,  guide boards, plates, grids,
      grating, or similar  devices  used
      to control the flow distribution or
      velocity of liquid in  a channel or

      screen usually consisting of  bars
      spaced with 1 to 5 inch openings
      to trap roots,  branches, rocks,
      rags,  and other large materials
      that may be encountered in the flow
      of a channel  or conduit.

BASE  - A foundation,  plate, natural  or
      engineered support  upon which a
      structure, channel,  machine, or
      other device is mounted.
      Chemical: A base includes a large
      variety of chemicals opposite in re-
      action to acids (alkali).

BED LOAD  -  Generally refers to  the
      oxygen demand requirements of
      benthic deposits,  sludge, muck,
      attached growths, moving materials,
      living or dead  that are exerted upon
      waters as a result of bottom or
      boundary dynamics.

      to the accumulated deposition of cell
      mass living or dead that collects at
      the bottom of a stream impoundment
      where velocity or catchment permits.

                                                 Glossary - Wastewater Treatment Technology
BIO-CHEMICAL  -  Resulting from the
      combined activities of biological
      and chemical transformations.
      Usually measured in terms of the
      ensuing chemical changes.

BIODEGRADATION -  The stabilization
      of wastewater contaminants by bio-
      logical conversion of pollutants into
      separatable materials at a higher
      oxidation state.

BIO FILTER - See Trickling Filter.

      living organisms to sustain life,
      growth, and reproduction.  Commonly
      the processes by which organisms
      degrade complex organic material
      into simpler substances at a higher
      oxidation state to obtain energy for
      life processes and growth of new
      cell mass.

BIOLOGY -  The science and study of living
      organisms, characteristics and be-

BOD  - Biological or biochemical oxygen
      demand.  A test  for estimation  of
      wastewater polluting effects in terms
      of the oxygen requirements for bio-
      chemical stabilization under specified
      conditions and time.

BRIDGING - A condition in which particu-
      lates or solids concentrates that would
      normally seek the lowest level of a
      restricted channel or basin, tend to
      hang up on  sidewalls.  The bridged
      material commonly may settle again
      with vibration, agitation, a change
      in flow direction, or increased flow

      amount of heat that will  raise the
      temperature of one pound of water
      one degree Fahrenheit.

BUFFER ACTION - An action exhibited
      by certain chemicals that limits the
      change in pH upon addition of acid
      or alkaline materials to the system.
      In surface water, the primary buffer
      action is related to carbon dioxide,
      bicarbonate and carbonate equilibria.

BULKING - A condition,  usually related
      to activated sludge.processing,  in
      which the sludge solids  separation
      from the liquid is inhibited.
      Rapid growth, filamentous organisms,
      and certain other factors that are but
      vaguely understood, tend  to produce
      a low density thin sludge that settles
      very slowly and has limited  compact -

BURNER, WASTE GAS - A device for
      burning the excess gas from sludge
CALORIE - That amount of heat required
      to raise one gram of water one
      degree Centigrade,  or Celsius.

CARBOHYDRATES - Naturally occurring
      compounds consisting of carbon,
      hydrogen and oxygen, that are con-
      sidered as energy foods and precursors
      of proteins and Fats in the natural
      food chain.

CATALYST - A substance that influences
      the rate of chemical change but either
      remains unchanged during the reaction
      or is regenerated thereafter.
      Generally applies to acceleration of
      reaction rates.

CATCH BASIN - A chamber,  well or other
      enlargement of a channel, designed
      to retain grit and detritus below the
      point of liquid overflow.

CATION  -  A positively charged ion in
      water solution. May be a single
      element or a combination of elements.
      such as Na+ in a water solution of
      NaCl (common table  salt).

CENT! - An expression used to indicate
      I/100 of a given standard unit
      centimeter (cm).  1/100 meter.

CENTIGRADE - A  temperature measure-
      ment scale in which the freezing point
      of pure water at sea level is desig-
      nated as 0°C and the temperature of
      boiling water  is designated as 100°C.
      This is more  properly termed the
      Celsius scale.

CENTRIFUGAL PUMP -  A pump consisting
      of a rotating impeller within a casing
      having an inlet near the center and
      an outlet or discharge at the tip of
      the impeller where centrifugal force
      is greatest.

Glossary  - Wastewater Treatment Technology
CENTRIFUGE  - A device for separation of
      solids or liquids of different densities
      by rotational energy; heavy materials
      move outward, less dense materials
      move toward a central  take-off port.

CHANNEL - A natural or artificial waterway
      which continuously or periodically con-
      tains flowing water.  A connecting link
      between two bodies of water with a
      definite bed  and sidewalls to confine
      the flow.

CHANNELING  - A condition in which certain
      portions of the flow within a channel or
      basin tend to seek a more limited dis-
      tribution than that resulting from the
      confining bed or sidewalls, i. e., the
      flow may channel along the top,  bottom
      or mid channel depth due to density,
      temperature, or some  form of obstruc-
      tion to uniform cross sectional flow.

      to control flow in a pipe or channel
      limiting it to one  direction.  Commonly
      a gate hinged at the top that is limited
      in movement by a seat  in a near
      vertical position so that it can open
      for flow in one direction but closed
      by reverse flow.

CHEMISTRY - A  science that deals with the
      composition and characteristics of
      substances and their behavior, i. e.,
      the transformations that they undergo.

CHLORAMINES - Products  of the combination
      of chlorine and ammonia.   Commonly
      classified as combined available chlorine.

CHLORINE  - A greenish yellow gaseous
      element having strong  disinfecting
      and oxidizing properties in water
      solution.  It is commercially available
      as compressed gas, liquid, or in
      combined form as a powder.   It is
      highly toxic  and irritating to skin, eyes,
      and lungs in significant concentrations.

CHLORINATION - The application of chlorine
      to water  or wastewater for the purposes
      of disinfection, oxidation, odor  control,
      or other  effects.  Pre-chlorination -
      before treatment; post-chlorination -
      after treatment; in-process chlorination
      - during  treatment.

      tank where chlorine is applied to the
CHLORINE TEST  -  Commonly refers
      to one of two methods separately
      listed:  see Ortho tolidine test;
             see Amperometric  test.

CHLORINE DEMAND - The difference
      between applied chlorine and residual
      available chlorine in aqueous media
      under specified conditions and
      contact time.  Chlorine  demand
      varies with dosage, time, temperature,
      nature and amount of the water im-

      A broad group of compounds containing
      chlorine,carbon, hydrogen  and some-
      times other  elements.  Generally
      originating from or associated with
      living or dead  organic materials. This
      group shows a wide range of toxicities
      but usually have relatively  little oxi-
      dizing energy compared to  chlorine.

CHLOROPHYLL  - The green coloring
      material or  pigments in plants that
      promotes the photosynthetic reactions
      forming organic materials  from in-
      organic  nutrients and light  energy
      within the living cells.

CLARIFIER - A basin or chamber serving
      as an enlargement of a channel to re-
      duce flow velocity sufficiently to per-
      mit separation of settleable or
      floatable materials from the carrier
      water (a sedimentation basin).

COAGULANT  - A chemical,  or  chemicals,
      which when added to water  suspensions
      will cause finely dispersed materials
      to gather into larger masses of im-
      proved filterability,  settleability,  or

COAGULATION - The process of modifying
      chemical, physical,  or  biological
      conditions to cause flocculation or
      agglomeration of participates.

COD  - A test for  the estimation  of the
      contamination of a wastewater  in
      terms of oxygen requirements  from
      a strong chemical oxidant under
      specified conditions, i. e.,  Dichromate,
      50% sulfuric acid and 145°C for 2 hours.

COLIFORM GROUP  - A group of bacteria
      that inhabits the intestinal  tract of
      man, warm-blooded animals,  and
      may be found in plants,  soil, air and

                                             Glossary - Wastewater Treatment Technology
     the aquatic environment.  Includes
     aerobic and facultative gram negative
     non-spore forming bacilli that ferment
     lactose with gas formation.

     collection system is comprised of the
     conduits controlled by public agencies
     to intercept house, commercial or
     industrial discharges and transport
     them to a treatment facility or dis-
     charge point.

     of suspension in which the participate
     or insoluble material is in a finely
     divided form  that reamins dispersed
     in the liquid for extended time periods.
     Usually cloudy or turbid suspensions
     requiring flocculation before clarifi-

     Generally refers to chlorine-ammonia
     compounds exhibiting a slower reaction
     with ortho tolidine,  determinable with
     phenyl arsene oxide after addition of
     potassium iodide under acid conditions
     and usually requires higher concentra-
     tion and longer time to kill in com-
     parison with free available chlorine.

COMBINED SEWER -  A sewer designed to
     carry wastewaters and storm waters
     in the same channel.

COMBINED SEWAGE - Consists of house-
     hold,  commercial or industrial wastes
     in combination with roof and surface
     storm drainage.


     a)  The act of cutting and screening
     materials contained in wastewaters.

     b)  To reduce the size of fibrous or
     amorphous materials.

COMMINUTOR - A device for cutting sew-
     age solids until they pass through an
     acceptable screen opening to improve
     pumping and wastewater processing.


     a)  A combination of two or more atoms
     having definite physical and chemical
     characteristics and mutually attracted
     to each other.
     b) Atoms in the elemental state are
     electrically neutral but the number
     of external electrons may be increased
     or decreased in response to conditions
     and nature of the atom.  An atom that
     becomes electrically charged may
     combine with another atom of opposite
     charge to form an electrically neutral

     a) The act of increasing the mass
     per unit  volume of one substance
     with respect to another, such as
     concentrating the solids in a sludge
     from 3% to 6<7c.
     b) A means of designating the  ratio
     of one substance with respect to
     another, such as 15 mg of suspended
     solids per liter  of water.

CONDITIONING - An action of improving
     possibilities for subsequent process-
     ing such as  chemical treatment to im-
     prove sludge dewatering or filtering.

CONING  -  A condition in a clarifier  sludge
     hopper where the solids concentrate
     or sludge is partially withdrawn to
     form a cone or  channel through which
     clarified liquid  is pumped out while
     most of the solids remain behind
     around the cone.  Infrequent sludge
     pumping tends to encourage this
     condition where the sludge tends to
     solidify and is resistant to fluid flow.

CONTAMINATION -  A general  term re-
     ferring to the introduction of materials
     into water that make the water less
     desirable for its intended use.  Also
     introduction of undesired substances
     into air, solutions, or other defined
     media (chemical or biological).

CRITERION (pi. CRITERIA)  - Something
     which can be measured.  Commonly
     used as a basis for standards.

CROSS CONNECTION - In plumbing, a
     physical connection between two dif-
     ferent water systems,  such as  be-
     tween potable  and polluted water lines.

     A unit of discharge rate such  as
     one cubic foot of gas per second
     past a given point.

 Glossary - Wastewater Treatment Technology
       a) A graphic plotted to represent
       changes in value of one quantity in
       reference to another.

       b) A deviation from a straight line
       without a sharp break or angularity.
 DATA - Records of observations or
       measurements of facts, occurrences
       and conditions in written,  graphical
       or tabular form.


       a) The remains  of something broken
       down or destroyed.

       b) An accumulation of fragments of


       a) To undergo decomposition.

       b) Implies  a slow change from a state
       of soundness or perfection.

       c) To decay.

 DEGRADE - To  reduce the complexity of
       a chemical compound.

 DE IONIZED WATER  - Water that  has been
       treated by ion exchange resins or com-
       pounds to remove cations and anions
       present in the form of dissolved salts.


       a) The conversion of oxidized nitrogen
       (nitrate and nitrite-N) to nitrogen gas
       by contact with septic wastewater solids
       or other reducing chemicals.

       b) A reduction process with respect
       to oxidized nitrogen.

 DETENTION PERIOD  - The theoretical
       time required to displace the  entire
       volume of a tank or basin at a given
       rate of discharge.  Tank volume -r
       rate of discharge.

       actual time required for a given unit
       of liquid to flow through the'tank or
       process unit.  Usually determined
       by tracer method and depends upon
       inlet and outlet geometry,  temperature,
       specific gravity, stratification,  and
       other factors.
DETERGENT  -  Something used for clean-
      ing.  Commonly consists of soap or
      surfactant plus  various additives or
      associated materials.

DETRITUS - The'heavier material moved
      by natural flow, usually along the
      channel bed.  Sand, grit or other
      coarse material.

DIAPHRAGM PUMP - A pump consisting
      of a rubber diaphragm (generally)
      fastened to a cylindrical casing
      having inlet and outlet valves.  When
      the diaphragm is raised,  liquid
      enters to be forced out the discharge
      valve on the reverse  stroke.

      duced by introducing  air through a
      dispersing mechanism into a liquid.
      Sufficient air pressure must be
      applied to overcome hydrostatic head
      and diffusor or pipe back pressure.

DIFFUSOR - A porous plate,  tube, bag,
      or other device, through which  air
      is forced into a  liquid in the form
      of small bubbles.

DIGESTED SLUDGE - Solids concentrates
      stabilized under aerobic or anaerobic
      conditions to preferentially decompose
      the more unstable fractions and pro-
      duce a residue of satisfactory disposal
      characteristics.  To  reduce the
      volatile fraction of the sludge.


      a)  To make thinner or more liquid.

      b) A ratio,  volume or weight of a
      more concentrated sample or effluent
      flow compared to that into which it
      is discharged.


      a) To make free of infectious

      b) To kill disease organisms.


      a) The discarding or throwing away.

      b) For wastewaters,  this may repre-
      sent any method of disposing, but
      usually involves some degree of
      degradation and discard in a non-
      pollutional manner.

                                               Glossary - Wastewater Treatment Technology

      a) Those materials dispersed in water
      in ionic,  atomic, or molecular form;
      an homogenous mixture or solution.
      b) Generally clear but may be colored.

      c) Present in true  solution form.

DISSOLVED OXYGEN (D. O.) - Dissolved
      molecular oxygen usually expressed
      in mg DO/1 or percent of saturation.

DISTILLED WATER - A purified water
      resulting from heat vaporization
      followed later by vapor condensation
      to separate the water from non-
      volatile impurities.


      a) A device to control flow into some
      desired direction or place.

      b) A device used to spread the flow
      evenly across a trickling filter surface
      or other process unit.

DIVERSION CHAMBER  - A basin or tank
      that may  be used to divert part of the
      flow from a channel.  May or may not
      contain treatment capabilities or a
      means of returning the diverted flow
      to the treatment plant when a shock
      load has passed.

DOSING SIPHON - A  device to permit inter-
      mittent dosing,  such as for a trickling
      filter.  Consists of a chamber that will
      fill gradually to a fixed level before
      starting a siphon that permits rapid
      drainage  to the filter or other treat-
      ment unit.

DRAINAGE TILE (Filter, or bottom tile)  -
      A vitrified tile underdrainage system
      laid on the bottom to support trickling
      filter stone,  sand,  or other filter
      media,  including sludge drying beds.
      These are specially prepared blocks
      or half-tiles containing slots for
      passage of water or air but restricting
      bed  media penetration.

DRYING  - The removal  of water by natural
      or engineered means.

DYNAMIC HEAD,  TOTAL -  The difference
      in pressure at the elevation of the
      pump discharge and the elevation at
      the pump  suction flange, plus the
      velocity head at the discharge minus
      the velocity head at the suction flange,
      all corrected to the same units and
      datum points.
ECOLOGY - The relation of an organism
      to its environment; i. e.,  how is an
      organism affected by his  surround-
      ings such as air, water,  heat, noise,
      contamination, etc.

EFFICIENCY  -  The ratio of materials
      out of a process to those  into that
      process usually expressed as a

EFFLUENT - A liquid or product water
      discharged from a  chamber, basin
      or other treatment operation.

      a) Elementary substance.

      b) A substance or kind of matter
      in which all atoms  are alike in that
      they will have the same average
      relative weight and the same number
      of external electrons.

ELUTRIATION - A washing operation.
      Sludge elutriation is an action where
      digested or process sludge is washed
      with sewage or effluent to remove
      fine particulates or certain soluble
      components.  The elutriate is re-
      cycled to process waters, the elu-
      triated solids are more readily

      ished level of metabolism in which
      various materials previously stored
      by the cells are oxidized.

ENTERIC ORGANISMS - Those organisms
      commonly associated  with the in-
      testinal tract.

ENTRAINMENT - A condition  or action
      that will cause an immiscible sub-
      stance to be mixed with another.
      Usually the result of turbulence or
      entrapment; i. e. , air bubbles in
      aqueous media.

ENZYME  - A soluble or colloidal organic
      catalyst produced by a living organ-
      ism.  Usually they are simple or
      conjugated proteins that catalyze
      specific reactions.

      a) Equal in force ,  amount,  or value.
      b) Chemical:  The  atomic or molec-
      ular weight of one substance that will
      react with one unit of  weight of another
      substance; i. e. , that weight of an

Glossary - Wastewater Treatment Technology
      alkali necessary to precisely equalize
      1 gram atomic wt. of H+ion.

 EUTROPHIC  - Well nourished; rich in dis-
      solved nutrients.

 EUTROPHICATION - An action involving
      the aging of lakes characterized by
      nutrient enrichment and increasing
      growth of plant and animal organisms.
      The net effect is to decrease depth
      until the lake becomes a bog and
      eventually dry land.   Man-made pol-
      lution tends to hasten the  process.
      that can adapt themselves to growth
      and metabolism under aerobic or
      anaerobic conditions.  Many organ-
      isms  of interest in wastewater
      stabilization are among this group.

FAHRENHEIT - A temperature scale in
      which pure water at  sea level has
      a freezing point at 32 ° and the
      boiling point is 212 °.

FATS - Naturally occurring compounds
      functioning as storage products in
      the living organisms.  Consist of
      carbon, hydrogen  and  oxygen in the
      form  of fatty acid  esters. Generally
      semi-solid or oily at normal temper-

FECAL COLIFORM - A group of organisms
      belonging to the coliform group and
      whose presence denotes recent fecal
      pollution from warm-blooded animals.
      Standard tests are available to differ-
      entiate the fecal coliform group from
      the other members of  the group which
      have a lesser sanitary significance.

FERMENTATION - A form of respiration
      by organisms which requires little or
      no free  oxygen,  yielding alcohol and
      carbon dioxide  as  end  products and
      releasing only part of  the food energy
      available; i. e.,  the conversion of
      sugars into alcohol by enzymes from

FILTER  -  A porous  media through which
      a liquid may be passed to effect re-
      moval of suspended materials.  Filter
      media may include paper, cloth,  sand,
      prepared membranes, gravel, as-
      bestos fiber, or other granular or
      fibrous material.
FILTER CLOTH  -  Fabric, wire or other
      material stretched over the drum
      of a vacuum filter and accessories
      to support the solids during cake
      formation and discharge the solids
      when and where desired.

FILTER FLOODING - The filling of a
      trickling filter with liquid to a level
      above the media by closing all out-
      let parts. Generally to control
      nuisance organisms  such as flies.

FILTER FLY - Small black flies commonly
      found in or near the  trickling filter.
      Commonly the Psychoda group.

FILTER LOADING  - The  mass (or volume)
      of applied oxygen demand  or solids
      per unit of filter area or volume.
      See load ratio.

FILTER MEDIUM - Any material over
      which water sewage  or other liquid
      is passed for purification  purposes
      by chemical,  biological or physical

      effect of fine  particles on  sand
      filters  or organic growth on trick-
      ling filters  that restricts normal
      passage of liquid through the filter
      as a result of filling void spaces.

FILTER RESIDUE  - That material which
      is retained on or in a filter.

FILTER UNLOADING -  A phenomenon
      in which normally attached growth
      or slime on trickling filter media
      becomes detached and either par-
      tially or completely  sloughs off.

FILTRATE - That liquid which has
      passed through a filter,

FILTRATION RATE - A rate of applica-
      tion of water  or wastewater to a
      filter.   Commonly expressed in
      million gallons per acre per day
      or gallons per square foot per min.

      settling basin or chamber for the
      mixed liquor  following secondary

FLAME ARRESTOR - A safety device
      in the handling of flammable gases.
      Usually consists of an enlargement
      in a pipe line containing a metallic

                                               Glossary-Wastewater Treatment Technglogy
      grid that allows passage of gas but
      acts as a barrier to the passage  of

FLIGHTS - A cross member of a conveyor
      system used for collection and trans-
      port of the collected material; i. e.,
      the boards fastened to a chain loop
      on either side of a primary clarifier
      that pushes scum along the surface
      to a collector trough and sludge along
      the bottom to the sludge collector.

FLOAT CONTROL  -  Commonly a device
      to control a pump or pumps according
      to the water level in a chamber or
      well as indicated by the float.  Usually
      operates a relay to control pump power,
      number,  or speed  of pumps in operation.

FLOATATION  - A  process for separation
      of solids from clarified liquid that
      causes particulates to be floated to
      the surface by means of attached air

FLOATING COVER - A gas  tight cover
      with a water seal supported by digester
      gas pressure  and capable of moving
      upward or downward with liquid and
      gas content of the digester.

FLOC - Gelatinous or amorphous solids
      formed by chemical,  biological or
      physical agglomeration of fine ma-
      terials into larger masses that are
      more readily separated from the liquid.

FLOCCULATION - The gathering together
      of fine particulate materials in a sus-
      pension to form loosely associated
      larger masses of solids agglomerates.

FLUME  - A  long narrow channel for gravity
      flow of liquid  from one point to another.

FLY AWAY BOD  -  Wastewater  stabilization
      operations such as trickling filters en-
      courage the development of insect larvae
      that serve as  scavengers during their
      development.   If the adult  form  of the
      larvae have functionable wings, the
      equivalent of oxygen demand consumed
      during development becomes fly-away

      includes that chlorine existing in water
      as the hypochlorous acid.  Character-
      ized by rapid  color formation with
      ortho tolidine.  Can be titrated in
      neutral solution with phenyl arsene
      oxide and produces a rapid organism
      kill in low concentrations.

FREE BOARD -  The vertical distance
      from the normal water level in a
      flume,  conduit, channel, basin, or
      other water enclosure, to the top
      of the confining structure.

FRESH SLUDGE  -  Recently deposited
      sludge from sedimentation tanks
      that has not been conditioned,
      processed, or progressed mater-
      ially into the  anaerobic action stage.

FUNGI -  Simple or complex organisms
      without chlorophyll.  The  simpler
      forms are one-celled;  higher forms
      have branched filaments and com-
      plicated life cycles.  Examples are
      molds,  yeasts and mushrooms.

FWPCA  - Federal Water Pollution Control
      Administration, U. S. Department  of
      the Interior.
GAS DOME  -  A chamber usually mounted
      on top of the digester cover for
      separation of gas from scum,  foam
      or liquid.

GAS HOLDER - A tank used for storage
      of gas from sludge digestion units
      for the purpose of meeting the gas
      demand  for burners, engines,  or
      other use during non-steady pro-
      duction or use periods.

      A chamber installed for housing
      devices  for controlling flow to
      various  parts of a collection, treat-
      ment or distribution system,
      including valves,  gates, and auto-
      matic or manual controls.

      a) The action of measuring some
      item such as flow, level, size,
      rate, etc.
      b) A device for gauging.
      c) A size designation or indicator
      for some definite item  such as 20-
      gauge wire,  16-gauge sheet steel.

GERMICIDE  - An agent that kills micro-

Glossary - Waste-water Treatment Technology
GRAVITY SYSTEM - A system of open or
      closed conduits in which the liquid
      flows by gravity (without pumping).

GRIT  -  The heavy material in water or
      sewage such as sand, gravel,  cinders,

GRIT CHAMBER  - An enlargement of a
      channel designed to reduce flow ve-
      locity adequately to permit differential
      separation of sand or grit from organic
      suspended material.  Usually approaches
      a linear flow velocity of 1 to 3 ft/ sec.

GRIT COLLECTOR -  A device placed in a
      grit chamber to  collect and to convey
      the more  coarse and dense grit parti-
      cles   out of the chamber  and permit
      return of  most of the organic or liquid
 HARDNESS - Commonly refers to the
      chemicals interfering with soap action
      or producing scale in boilers or
      heating units.  Specifically refers to
      Calcium and Magnesium salts;  some-
      times including Iron, aluminum,  and

 HEAD LOSS - The difference in pressure
      between the inlet and outlet pressure
      of a given process unit arising as a
      result of flow resistance within the
      process unit, such as the head loss
      due to friction  of a filter media and
      filter residue.

 HEAT EXCHANGER  COILS - A piping lay-
      out designed to circulate a liquid media
      within the contents of the process unit
      but without mixing with the process
      media for the purpose of adding or re-
      moving heat; i. e., hot liquids may be
      circulated within a digester to  raise
      digester temperature.

 HUMUS - A brown or black complex and
      variable material resulting from de-
      composition of plant or animal matter.

 HYDROLYSIS - The addition of water to
      any chemical compound.  Commonly
      involved in splitting complex sub-
      stances by addition of water to form
      more simple compounds.

 HYDROSTATIC HEAD  - The pressure
      exerted by a given height of liquid
      above a given datum point.  May be
      listed in feet of head, pounds per
      square inch, or other criteria.
IMPELLER  - A rotating set of vanes to
      impart motion to a fluid,  commonly
      within a casing where dynamic energy
      of fluid increases from the center
      to the  tip of the vanes.  May be closed
      or open depending on a tube or paddle

IMHOFF  CONE - A conical glass container
      commonly one liter capacity,  having
      the upper larger  diameter end open
      and the closed apex downward with
      graduations to assist estimation of
      the volume of settleable solids after
      an arbitrary time interval for set-
      tling (usually one hour).

IMHOFF  TANK - A deep two-story tank
      originally patented by Karl Imhoff.
      The floor of the upper chamber is
      s lotted for transfer of settleable
      solids from the settling chamber.
      The lower chamber serves for an-
      aerobic digestion and storage of

INDICATOR  -  May include the  color  change
      of a dye, electronic sensor response,
      or other means of estimating the
      equivalence point of a reaction be-
      tween  two different materials.

      a) The entrance of ground water into
      a sewer through breaks, defective
      joints, or porous walls.

      b) The penetration of water through
      the soil from surface precipitation,
      stream or impoundment boundaries.

INFLUENT  - That material entering a
      process unit or operation.

INORGANIC  -  Being composed of material
      other  than plant or animal materials.
      Forming or belonging to the inanimate

INTERCEPTOR -  An intercepting sewer
      designed to carry the dry weather
      flow from a community to a treatment
      plant,  but not large enough to carry
      storm water above some preset ratio
      to dry weather flow.  May be used
      to collect lateral sewer flows.

                                             Glossary - Wastewater Treatment Technology
LAGOON - A natural or artificial basin used
      for storage and/or stabilization of
      wastewater or sludge.  Sometimes
      used for indefinite storage for dis-
      posal purposes.  Commonly the lagoon
      depth is greater than a wadable depth
      but not greater than twenty feet.

LATERAL SEWER  - A sewer that dis-
      charges into a branch or main sewer
      and has no other  tributaries other
      than individual house connections.

LIQUID SLUDGE  -  An organic solids con-
      centrate usually formed by deposition
      from wastewaters.  The water content
      varies with the origin and nature of
      the sludge; usually has enough water
      to permit pumping but does not contain
      significant separatable free water.

LOAD - The load to a  process is that which
      is contained in the inflow to that process.
      It may be expressed as hydraulic,
      oxygen demand, solids, or other

LOAD RATIO - An index of loading, in-
      cluding mass  input per unit of capacity
      per unit of time.   Mass maybe ex-
      pressed in Ibs.,  BOD, COD,  Susp.
      or volatile solids, capacity in volume,
      weight of solids or volatile solids in
      process,and time.usually in days.

LYSIS - To decompose,  loosen, or separate
      into component parts.
MANHOLE - An opening by which access
      may be achieved for inspection,
      maintenance,  or repair of a sewer,
      conduit, or other buried structure
      or appurtenance.

MANOMETER - An instrument for measuring
      pressure.  Usually consists of a U-
      shaped tube containing a liquid, the
      surface of which moves proportionally
      in one  open end with changes in
      pressure exerted upon the other end.

      produced by mechanical energy of
      the turbine, pump,  paddle,  or other
      device  that imparts  an intimate mix-
      ture of liquid  and air.

MEMBRANE FILTER - A flat, highly porous
      flexible plastic  disc,  commonly about
      0.15 mm in thickness and 47-50 mm in
     diameter.  Membrane filters having
     a pore size of 0.45^  are used in
     water microbiology to trap organisms,
     and.by use of standard media and
     conditions, direct enumeration by
     colony count of selected organisms.

MENISCUS - The curved upper surface
     of a liquid in a tube that is concave
     upward when the containing walls
     are wetted by the confined  liquid,
     and convex upward when they are not.

MESOPHILLIC - Medium temperature
     loving.   Organisms capable of opti-
     mum metabolic activities at temper-
     atures from about 80°-1100F, 26b-

METER  - The length of a reference
     platinum bar used as a standard
     unit of measurement  of length in
     the metric system.   1 meter =
     39. 37 inches.

MICRO  - 1/1, 000, 000 of a  unit of measure-
     ment,  such as microgram, microliter.

MICROBIOLOGY -  The science  and study
     of microbiological organisms and
     their behavior. Commonly related
     to the study of pathogenic organisms.

MICROORGANISM - Commonly an organ-
     ism too  small to be observed indi-
     vidually by the human eye without
     optical aid.

MILLI-  - An  expression used to indicate
     1/1000 of a standard unit of weight,
     length or capacity (metric  system).

     Milliliter  (ml)   I/1000 liter   (1)
     Milligram (mg)   I/1000 gram  (g)
     Millimeter (mm)  I/1000 meter (m)

     of the equivalent weight; usually
     expressed in milligrams (mg).

MG/L -  A unit of concentration  on a
     weight/ volume basis:  Milligrams
     per liter.  Equivalent to ppm when
     the specific gravity of the liquid is

MIXED LIQUOR -  A mixture  of  return
     sludge and wastewater in the aerator
     of an activated sludge plant.  Also
     may be used in reference to mixed
     aerobic  or anaerobic digesters.

 Glossary - Wastewater Treatment Technology
 MIXING ZONE  -  An area where two or more
       substances  of different characteristics
       blend to form a uniform mixture; i. e.,
       chlorine application, heated water, or
       other discharged materials entering a
       water mass will show significant dif-
       ferences of chlorine residual,  tem-
       perature or other criteria,  depending
       upon the sampling location throughout
       the mixing zone and approach uniform
       results with respect to lateral,longi-
       tudinal,and  vertical sampling positions
       when mixing has been completed,

 MOISTURE CONTENT - The content of
       water in some other material.   Com-
       monly expressed in percentage of
       moisture in soil, sludge or screenings.

       statistical method of determining
       microbial populations.  A multiple
       dilution tube technique is utilized
       with a standard medium and observa-
       tions are made for specific individual
       tube effects.  Resultant coding is
       translated by mathematical probability
       tables into population numbers.
 NITRIFICATION  - The biochemical con-
       version of unoxidized nitrogen
       (ammonia and organic N) to oxidized
       nitrogen (usually nitrate).


       a) A means of expressing the concen-
       tration of a standard solution in terms
       of the  gram equivalents of reacting
       substances per liter.

       b) Generally expressed as a decimal
       fraction,  such as  0.1 or 0. 02 N.

       a) Anything essential to support life.

       b) Includes many  common elements
       and  combinations  of them.  The major
       nutrients include carbon, hydrogen,
       oxygen,  nitrogen, sulfur, and phosphorus.
       c) Nitrogen and phosphorus are of
       major concern because they tend to
       recycle and are hard to control.
 ODOR CONTROL - In wastewater treatment
      this generally refers to good house-
      keeping in the plant and aeration.
      chlorination or other operations to
      prevent onset of malodorous septicity
      in the wastewater flow.


      a) Liquid fats  of animal or vegetable

      b) Oily or waxy mineral oils.

ORGANIC - Substances formed as a result
      of living plant  or animal organisms.
      Generally contain carbon as a major

ORGANIC CHLORINE -  Compounds con-
      taining chlorine in combination with
      carbon, hydrogen and certain other

ORIFICE METER  -  A device consisting
      of a flange set in a pipe section
      containing an opening smaller than
      the pipe.   Pressure readings above
      and below the orifice may be related
      to flow.

      The dye,  ortho tolidine, under highly
      acid conditions, produces a yellow
      color proportional in intensity to the
      concentration of available residual
      chlorine and certain other oxidants
      or interfering  materials.

OUTFALL SEWER - The outlet or channel
      through which  sewage effluent is dis-

OXIDATION  -  Chemically:  The addition
      of oxygen, removal of hydrogen, or
      the removal of electrons from an
      element or compound.

OXIDATION POND - A shallow basin
      employed for the stabilization of

OXYGEN AVAILABLE - That part of the
      oxygen available for aerobic stabil-
      ization of organic matter.  Includes
      dissolved oxygen and that available
      in nitrite or nitrates, peroxides,
      ozone, and certain other forms of

OXYGEN BALANCE - Refers to the dy-
      namic relationship among the avail-
      able oxygen assets and the oxygen
      requirements for stabilization of
      oxygen demanding materials in a
      treatment plant or receiving water.

                                               Glossary -Wastewater Treatment Technology
OXYGEN DEPLETION - The loss of oxygen
      from water or sewage due to biological,
      chemical or physical action.
PARASITE  - A living organism deriving its
      nutrients at the expense of another
      living organism, giving nothing in re-

PARSHALL FLUME - A device for estima-
      tion of the flow in an open conduit.
      Consists  of a constricting section,
      a throat,  and an expanding section.
      The throat contains a sill over which
      the liquid passes.  The pressure
      change over the  sill can be related
      to quantity of flow.

      detectable solid  material dispersed
      in a gas or liquid.  Small sized par-
      ticulates  may produce a smoky or hazy
      appearance in a  gas; milky or turbid
      appearance in a  liquid.  Larger partic-
      ulates are more readily detected  and
      separated by sedimentation or filtration.

PARTICULATES - Pertaining to small sus-
      pended solids in a gaseous or liquid media.

      concentration signifying parts of some
      substance per million parts of dis-
      persing medium. Equivalent numer-
      ically to  mg/1 only when the specific
      gravity of the solution is 1.0.

      fungal, viral,  or other organisms
      directly involved with diseases of
      plants, animals, or man, are in-
      cluded among this group.

      expressed as a percentage of the
      material  removed from process water
      in terms  of the material entering.
      Sometimes referred  to as reduction.

pH - An index  of hydrogen ion activity.
      Defined as the negative logarithm
      (base 10)  of H  ion concentration at
      a given instant.  On a scale of 0 to 14
      pH 7. 0 is neutral,  pH less than 7. 0
      indicates a predominance of H+ or
      acid  ions; pH greater than 7. 0 indi-
      cates a predominance of OH" or
      alkaline ions.
PNEUMATIC EJECTOR  -  A device for
      pumping sludge, sewage, or other
      liquid by admitting the fluid into a
      chamber through one check valve
      and forcing it out of another by air
      pressure in the chamber above the

POLLUTION - Anything appearing in water
      that renders it unacceptable in  terms
      of established water quality standards.
      Commonly conditions or contaminants
      that interfere with  subsequent bene-
      ficial uses of the water.

POND -  A basin or catchment used for
      retention of water for equalization,
      stabilization, or other purposes.
      Commonly less than five feet in depth.

PONDING  - With reference to trickling
      filtration,  ponding  refers to a plugging
      of the filter media  by slimes  or solids
      to restrict downward movement of
      wastewater sufficiently to cause sur-
      face  accumulation of liquid either
      partially or completely.

PRECIPITATE - The formation of solid
      particles in a solution, or  the solids
      that settle as a result of chemical
      or  physical action that caused solids
      suspension from solution.

PRESSURE -  The total load or force acting
      upon a surface.  In hydraulics, the
      term commonly means pounds per
      square inch of surface, or kilograms
      per square cm above atmospheric
      pressure on site.  (Atmospheric
      pressure at sea level is about 14. 7
      pounds per square  inch.)

PRIMARY  SLUDGE  -  Sludge obtained
      from a primary sedimentation tank.

PRIMARY  TREATMENT -  Commonly the
      separation of settleable or floatable
      materials from carrier water.
      Usually preceded by pretreatment
      such as  coarse screens,  grit sep-
      aration, comminution.

PROCESS  - A series of  operations or
      actions that lead to a particular
      result.  A combination of unit oper-
      ations that may be  assembled and
      used for a given treatment objective.

 Glossary - Wastewater Treatment Technology
 PROTEINS - Naturally occurring compounds
      containing carbon, hydrogen,  nitrogen,
      and oxygen, with smaller amounts of
      sulfur and phosphorus,  and trace com-
      ponents essential to the living cells.
      An essential food associated with
      meat and  eggs.

 PROTOZOA - Single cell or multiple cell
      organisms,  such as amoeba, celiates,
      and flagellates.  Commonly aquatic
      and generally  derive most of their
      nutrition from preformed organic food.

      temperature loving organisms, or
      having a  competitive  advantage
      over other organisms at lower tem-
      peratures; i.e., from about 10°C
      downward to the freezing point.

 PUTREFACTION  -  Biological decomposition
      of organic matter with the formation
      of ill-smelling products,  such as H2S,
      amines, mercaptans.  Associated with
      anaerobic conditions.
QUIESCENT - Characterized by a lack of
      or negligible movement of the sus-
      pending media, such as liquid or gas.
      Still or absence of turbulence.
      b) An individual who tabulates or
      maintains records of events,  actions
      or measurements.


      a) To make smaller or to remove
      from a given amount of material

      b) Chemistry: The removal of
      oxygen, addition of hydrogen,  or
      the addition of electrons to an ele-
      ment or compound.

RELIEF SEWER -  A sewer built to carry
      the flow in excess of the capacity of
      an existing sewer.

      Residual Chlorine.

RETURN SLUDGE - Sludge returned from
      process to the influent flow.  Com-
      monly return activated sludge from
      a secondary clarifier.  Also may
      include sludge from a clarifier after
      trickling filtration.

ROTARY DISTRIBUTOR -  A device usually
      mounted on a center post with hori-
      zontal arms extending to the edge of
      a circular trickling filter for distri-
      bution of flow over the entire bed
      wastewater prior to treatment.

      using a piston within a casing fitted
      with suction and discharge valves.
      Movement of the piston in one direction
      fills the casing, the reverse  movement
      forces liquid into the discharge line.
      May be vertical or horizontal.

 RECIRCULATION  -  The return of effluent
      to the influent of a process unit to
      reduce influent concentration, sta-
      bilize the system, maintain hydraulic
      flow, to reprocess, or for other bene-
      ficial reasons.


      a) A device to keep a continuous or
      intermittent record of some measured
      item such as flow,  velocity,  applied
      power,  etc.
SALT - A  chemical compound formed as
      a result of the interaction of an acid
      and an alkali (base).   The common-
      est salt is sodium chloride formed
      from hydrochloric acid and sodium
      hydroxide.  This ionizes in water
      solution to form Na+ and Cl~.

SANITARY SEWER  - A sewer designed
      to receive and to convey household,
      commercial or industrial waste-
      water mixtures.

      living upon dead or decaying organic
      matter.  Organisms that utilize non-
      living organic matter as a food.

SATURATION - Commonly refers to the
      maximum amount of any material
      that can be dissolved in water or
      other liquid at a given temperature
      and pressure.  For oxygen, this
      commonly refers to a percentage
      saturation in terms of the saturation
      value, such as about  9 mg Oo/l at
      20° c.

                                              Glossary - Wastewater Treatment Technology
SCAVENGERS  - Organisms that feed
      habitually upon refuse or carrion.
      In water pollution, this commonly
      refers to worms, insect larvae,
      bloodworms,  sow bugs,  and crusta-
      ceans.  Or, more properly,  oligo-
      chaetes,  chironomids and isopods.

SCREEN - A device with openings, gener-
      ally having a relatively uniform size,
      that permit liquid to pass but retain
      larger particles.  The screen may
      consist of bars,  coarse to fine wire,
      rods, gratings, paper,  membranes,
      etc., depending upon particle size
      to be retained.

SCREENINGS  - Material removed by the

SCUM BOARD  - A  vertical baffle, above
      and below the liquid surface  of a basin
      or  tank, designed to prevent the
      passage of  or to contain floating
      material  within designated limits.

SCUM BREAKER - A  device installed in a
      sludge digestion  tank to disperse sur-
      face accumulations.  Generally
      accomplished by means of mechanical
      agitation, gas or liquid recirculation,
      to promote mixing and destratification.

SCUM COLLECTOR -  A mechanical device
      for skimming and removing  scum or
      floatable  material from the surface
      of a tank.

SECOND FOOT - An abbreviation for
      cubic foot per second.  A rate term.

      used to convert dissolved and colloidal
      materials in wastewater to a form that
      may be separated from the water.
      Commonly consists  of biodegradation
      and conversion to cell mass  in a
      separatable form with partial oxida-
      tion,  such as in activated sludge,
      trickling filtration,  or oxidation ponds.

SEDIMENTATION  -  The process of subsi-
      dence and deposition of suspended
      matter from wastewater by gravity.
      Also called clarification, settling.

SEPTIC SLUDGE - That sludge  which has
      reached a stage of anaerobic putre-
      faction (sulfate reduction).  Includes
      that from Imhoff, septic, or sludge
      digestion tanks.
     Wastewater in which available oxy-
     gen has been depleted and the
     reduction of sulfates has begun.  A
     result of anaerobic putrefaction.


     a)  Includes materials that will settle
     by gravity under low flow velocities.

     b)  Commonly expressed in terms
     of the volume of solids accumulating
     in an Imhoff cone after one hour on
     a volume basis.

SETTLING BASIN - A natural or engineered
     enlargement of a channel that reduces
     velocity sufficiently to permit sedi-
     mentation of settleable particulates.

SEWAGE -  See Wastewater.

     produced from anaerobic (septic)
     sewage solids.  Generally contains
     marsh gas (methane) and carbon
     dioxide with hydrogen sulfide and
     other components in minor propor-

SEWER - A pipe or conduit,generally
     covered,for the purposes of con-
     veying wastewaters from the point
     of origin to a  point of treatment or

SEWERAGE SYSTEM - A system  of
     sewers and appurtenances for the
     collection, transportation and
     pumping of used waters for a given
     area  or basin.  Any treatment de-
     vice or facility and its outfall con-
     duit   are a part of the  system.

SHORT CIRCUITING  - Hydraulic: A  con-
     dition in which one part or unit of
     flow into the basin reaches the outlet
     in much less time than that required
     for a uniformly mixed flow.
     Electrical:  A situation in which an
     electric current is out of place in
     relation to its controlled pathway.

     of organisms  growing on wastewater
     nutrients with the formation of mu-
     cilaginous  covering,  streamers or
     clumps. May consist of bacteria,
     molds, protozoa or algae.

Glossary - Wastewater Treatment Technology
SLOUGHING  - A phenomenon associated
      with trickling filters and contact
      aeration units where slimes build up
      to a varying degree, then slip off
      into the effluent.

SLUDGE  - Accumulated or concentrated
      solids from sedimentation or clari-
      fication of  wastewater.  Contains
      varying proportions of solids in
      wastewater depending upon source,
      process, and nature.

SLUDGE BANKS  - An accumulation of solids
      including silt,  mineral,  organic, and
      cell mass particulate material, that
      is produced in the aquatic system
      characterized by low current velocity.
      Generally refers to gross deposits of
      appreciable depth.

SLUDGE CAKE - The solids remaining
      after dewatering sludge  by vacuum,
      filtration, or sludge drying beds.
      Usually forkable or spadable, with
      a water content of 30 to  80%.  Also
      may occur  on the boundaries  of
      surface water.

SLUDGE COLLECTOR -  A mechanical
      device,  including rake,  drag, or
      suction, for collecting settled sludge
      from the bottom of a clarifier into a
      sump or other withdrawal system.

SLUDGE DIGESTION - A process by which
      organic matter in sludge is converted
      into more stable or separatable form
      through the action of living organisms.
      May be the result of aerobic or an-
      aerobic digestion,

SLUDGE DRYING BED -  An area used to
      discharge wet sludge for drainage
      and drying.  Generally prepared of
      porous bed material surrounded by
      sidewalls to contain the  sludge while
      the  liquid percolates into an under-
      drain system.   May be covered or

SLUDGE FILTER -  A device  to effect
      partial water removal from wet
      sludge, usually with the aid of vacuum
      or pressure of preconditioned sludge.

SLUDGE SYNTHESIS - The net gain in
      sludge  mass in a process over a
      period  of time as a result of simul-
      taneous growth of cell mass and
      endogenous oxidation within it.
SLUICE GATE  -  A gate constructed for
      adjustment  to control the flow in a
      channel by gate position.


      a) An homogenous mixture,  commonly
      gas,  liquid,  or solid in a liquid that
      remains clear indefinitely.

      b) Generally an atomic, ionic,  or
      molecular dispersion in a liquid (may
      be colored).

      c) A  water  solution  of dissolved

      a) The weight  of a material per unit
      volume in reference to the weight
      of water at  maximum density.

      b) Water at 4°C has a weight of Ig
      per ml.   The weight ratio of any
      substance divided by the weight of
      water is the specific gravity.


      a) A  device, generally rubber, used
      for dislodging  and removing solids;
      scum or other materials from a
      b) Metal or wood blades to move
      sludge solids along  the bottom of
      a clarifier.

      a) The ability of any substance to
      resist putrefaction.

      b) Ability of an engineered structure
      to resist distortion  or overturn when

      a) The activity proceeding along the
      pathway to  stability.

      b) In organic wastes,  generally
      refers to oxidation via biochemical
      pathways and conversion to gaseous
      or insoluble materials relatively
      inert to further change.

STANDARD - Something  set by authority.
      Having qualities or attributes re-
      quired by law and defined by mini-
      mum or maximum limits of accept-
      ability in terms of established
      criteria or measurable.indices.

                                             Glossary - Wastewater Treatment Technology
STANDARD METHODS - Methods of analysis
      prescribed by joint action of APHA,
      ASCE,  AWWA, andFWPCA. Methods
      accepted by authority.

STEP AERATION - A procedure for adding
      increments of wastewater at various
      points along the line of flow in an
      activated sludge aerator.

STERILIZATION -  The process of making
      a medium  free of living organisms
      such as by killing them,  filtering
      through a porous medium fine enough
      to be a barrier to the passage of
      organisms, etc.

STORM OVERFLOW - A device such as a
      weir, dam, or orifice, in a combined
      sewer that will intercept design flow
      but permit excess storm flow to dis-
      charge directly.  The overflow con-
      tains a mixed discharge  of storm and
      other sewer components.

STORM SEWER  - A sewer which carries
      storm water from roofs,  surface wash
      and street drainage.

STUCK DIGESTER  - Any of a series of
      events that results in  serious mal-
      function of the digester.  Commonly
      refers to anaerobic digestion where
      overloading, temperature control,
      toxicity, or other factors, result in
      an excessive acid production with
      serious limitations of gasification,
      stabilization,  and solids concentration.


      a) The base or media in which an
      organisms lives.

      b) The liquid in an activated sludge
      aeration tank.

SUPERNATANT LIQUOR - The liquid over-
      lying deposited sludge.  Commonly
      that fraction of liquid in  an anaerobic
      digester located over the deposited
      material and beneath possible surface
      floating material.

      a) A chemical that,  when added to
      water, will greatly reduce the surface
      tension of the solution.

      b) The surface active component in
      a detergent mixture.
SUSPENDED SOLIDS  -  The concentration
      of insoluble materials suspended or
      dispersed in waste or used water.
      Generally expressed in mg/liter on
      a dry weight basis.  Usually deter-
      mined by filtration methods.

SYNERGISM - Refers to the action pro-
      duced when two or more substances
      in combination have a greater effect
      than that produced by the additive
      effects of each one separately.
TAPERED AERATION - A procedure for
      adjusting air input along the line of
      flow of an activated  sludge aerator
      according to need.  Usually requires
      addition of more air per unit of
      volume at the inlet end of the aerator.
     Waste Treatment.
- See Advanced
      heated discharges to surface water-
      ways.  The largest contributor of
      heated discharges is associated
      with power production.

THERMOPHILLIC - High temperature
      loving organisms.  Generally con-
      sidered to include organisms having
      a favorable competitive advantage
      at temperatures above 110°F or42°C.

THIEF - A term applied to a sampling
      tube used to remove a core of
      sample from a bag or bulk material.

TITRATION  -  The careful addition of a
      standard solution  of known concen-
      tration of reacting substance to an
      equivalence point  to estimate the
      concentration of a desired material
      in a sample.

TOC  - Total Organic Carbon.  A test
      expressing wastewater contaminant
      concentration in terms of the car-
      bon content.

TOTAL SOLIDS - Refers to the solids
      contained in dissolved and suspended
      form in water.  Commonly deter-
      mined on a weight basis by evapora-
      tion to dryness.

Glossary - Wastewater Treatment Technology
TRICKLING FILTER  - A treatment process
      employing downward flow of wastewater
      over the surfaces of a rock or grid
      system with a large void space for
      upward movement of air.   Slime
      organisms accumulate to effect bio-
      logical stabilization.
UNIT OPERATION  - A particular kind of
      a physical change that is repeatedly
      and frequently encountered as a step
      in a process such as filtration,
      aeration, evaporation, mixing,  or


      English - foot, pound, second.
      Metric  - centimeter,  gram, second.
      Abbreviations: ft.,  Ib., sec.
                    cm., g.,  sec.

USPHS -  United States Public Health
      Service, Department of Health,
      Education and Welfare.

      A list of standards prescribed for
      potable water acceptable for use on
      interstate carriers.   Deal with
      sources, protection, and bacterio-
      logical, biological,  chemical and
      physical criteria—some mandatory,
      some desired. Official for  municipal
      use only upon acceptance by State and
      local authorities.
VELOCITY (FLOW)  -  A rate term expressed
      in terms of linear movement per unit
      of time.  Commonly expressed in.
      ft per sec (English) or cm/sec (Metric).

VENTURI METER - A device for estimating
      flow of fluid in closed conduits or pipes.
      Generally based  upon constricting and
      enlarging pipe sections with pressure
      at the full size and the point of maximum
      constriction.  Differences in pressure
      can be  related to flow.

VIRUS - A term  generally used to designate
      organisms that pass filtration media
      capable of removing bacteria.  Tech-
      nically described as a collective term
      covering disease stimuli held by some
      to be living organisms and by others
      to be nucleic acids capable of repro-
      duction and growth.
VOLATILE ACIDS - A group of low molec-
      ular weight acids such as acetic and
      propionic, that are distillable from
      acidified solution.


      a) Refers to those chemicals having
      a vapor pressure low enough to
      evaporate from water readily at
      normal temperatures.

      b) With reference to dry solids, the
      term includes loss in weight upon
      ignition at 600°C.

VOLATILE SOLIDS - The quantity of
      solids in water that represents a
      loss in weight upon ignition at 600°C.
WASTEWATER  - Refers to the used water
      of a community.  Generally contam-
      inated by the waste products from
      household, commercial or industrial
      activities. Often contains surface
      wash, storm water and infiltrations


      a) Commonly refers to activated
      sludge produced  in excess of that
      required for return process.

      b) Any solids concentrate to be
      routed for disposal.

      selected analytical measurements
      with limits designated to be accept-
      able or unacceptable in reference
      to water quality standards.

      set by authority on the basis of water
      quality criteria required for bene-
      ficial uses.

WEER  - A device used for surface over-
      flow from a tank, basin or chamber.
      Generally designed to smooth out
      discharge flow to minimize  turbu-
      lence within the detention basin.
      May be used to measure discharged

WEIR BOX - An enlargement of the
      channel upstream of a weir to re-
      duce the velocity and turbulence
      before reaching the weir.

                                              Glossary - Wastewater Treatment Technology

      a) An artificial excavation or shaft
      that collects water from interstices
      of the soil or rock.

      b) Also an engineered structure for
      the housing of pumps or other equip-
      ment below ground level.

WET OXIDATION  - Oxidation of substances
      such as organic contaminants in water
      media. Includes biological oxidation
      and physical chemical oxidation, such
      as that obtained at elevated tempera-
      ture, pressure,catalyst or other pro-

WPCF - Water Pollution Control Federation.
      An organization composed of individuals
      engaged in the advancement of knowledge
      in research,  design, operation, and
      control of water pollution in relation
      to man and his environment.

      a) To give up or relinquish.

      b) To bear or bring forth as a result
      of cell division.

      c) To produce as a result of invest-
      ment of  energy,  materials, or time.

      d) The amount or quantity produced
      per  unit of raw material.

YIELD  FACTOR - A decimal fraction or
      percentage of product per unit of input.

   1    Any of the standard dictionaries.

   2    Glossary, Water and Sewage Control
           Engineering.   APHA, ASCE,
           AWWA, FSWA.  (1969)

   3    Glossary, Ohio Operator Training

   4    Jacobs, MorrisB., Gerstein, Maurice J.,
           and Walter, WilliamG.   Dictionary
           of Microbiology.  D. Van Nostrand,
           Inc.   (1957)

   5    Rose, Arthur and  Elizabeth.  Condensed
           Chemical Dictionary, 7th Ed. ,
           R einhold P ubli shing C o.  (19 61)

   6    U. S. Dept. of Interior, Office of Water
           Resources Research. Water Re-
           sources Thesaurus. (Nov. 1966)

   7    Geckler, JackR.,  Mackenthun,  K. M.,
           and Ingram, W. M.  Glossary of
           Commonly Used Biological and
           Related Terms in Water and Water
           Control.   Env. Health Series, U. S.
           Dept. HEW  (July 1963)

   8    Mathews, John E.  Glossary of Eco-
           logical Terms.  Roberts. Kerr
           Water Research Center, Ada, OK
           In press.
ZOOGLOEA  - A jelly-like matrix developed
      by certain microorganisms at some
      stage in their life cycle.  Commonly
      associated with sludge flocculation in
      biochemical treatment operations.

Many individuals,  unpublished memoranda
and literature sources contributed to the
selection of terms and key ideas included
in this glossary.  Contributors are too
numerous to list individually, but their
assistance is gratefully acknowledged.
This outline was prepared by F. J. Ludzack,
Chemist, National Training Center, Office
of Water Programs,  EPA,  Cincinnati, OH 45268.

70      80     9p    100





Concentration of Pollutional Load

       for Various Flovs
                              5   6  7  8  9 10
                                                              3O    4O   sO  eO 7OsOaOioO
                                     Flow -  eft

   Source:   Thomas J. Powers,  III.   FWPCA, Department  of the Interior,

                                  Flow Conversion Chart
                                                   5  6
                        Stream or Effluent Discharge - Units of Flow
Source:   Thomas J. Powers, III.   FWPCA, Department of  the  Interior.

    Lagoon Volume
 Thousands of
 Cubic Feet
  Lagoon Holding Capacities
         Source:  Thomas J. Powers, III,
  Lagoon Area, acres
FWPCA.  Department  of the  Interior

                              POWERS DATA SHEET No.  397
                                    xAere Feet Mr Tear
                                    Acre Feet Per 30 Dtys"

                                    Acre Feet
    2.5-L_J _$_•_—_
                                                Mlirato —

                                  "tnbic Feet Rir Second-
Flow of Fluids Conversion Chart
With this chart you can conveniently deter-
mine equivalent units of discharge for fluids.
Merely line up a straight edge with the middle
of the  chart and a known discharge; read the
equivalent on the other scales.
Example:  Discharge from a given pipe is
1100 gallons per minute.  How many gallons
per  day are discharged?  Lining up 1100 on
the gallons per minute scale with the chart
center,  we read 1, 580, 000 gallons per day on
the appropriate scale. On other scales we
can determine that the flow is equivalent to
2. 45 cu ft per sec.
The scales cover sufficient range to allow you
to find values of any magnitude by multiplying
or dividing the scales by factors of ten. With
a little ingenuity, you can determine  several
units not shown directly.
"Reprinted with permission from POWER, October 1965"
"Copyright McGraw-Hill, Inc.,  1965. "
                                                               S. R. Ross, Denver,  Colorado
                                                                                          • 5
 i1.- U.S. GOVERNMENT PRINTING OFFICE 1972— 759-396/87