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SECTION 6
SOILS AS A MEDIA FOR WASTWATER TREATMENT AND DISPOSAL
WASTEWATER ABSORPTION CAPABILITIES OF SOILS
Proper performance of conventional on-site waste-water disposal systems
depends upon the ability of the soil or soil material to absorb and purify
the waste-water. Failure occurs if either of these functions are not performed.
Both are directly related to the hydraulic conductivity characteristics of the
soil, which are largely controlled by the pore geometry of the material. De-
tailed discussion of this topic is contained in Appendix B.
Liquid Movement Through Soils
Soil Porosity and Permeability—
Soil is a complex arrangement of solid particles and pores filled with
ever-changing amounts of air and water. The size and shape of these pores is
a function of the soil's texture (particle size distribution) and its structure
(the arrangement of the solid particles). In sandy soils, the voids are
simply packing pores that exist between the individual grains. When signifi-
cant amounts of clay and organic matter are present, soil particles adhere to-
gether to form aggregates or peds. Planar voids form separating the peds.
Tubular channels formed by plants and animals living in the soil and irregularly
shaped discontinuous pores, called vughs, are also found in soils (Figure 5).
Intrinsic soil permeability or the capability of the soil to conduct
water is not determined by the soil porosity but rather the size, continuity
and tortuosity of the pores. A clayey soil is more porous than a sandy soil,
yet the sandy soil will conduct much more water, because it has larger, more
continuous pores. These twisting pathways, with enlargements, constrictions
and discontinuities through which the water moves, are constantly being altered
as well. The soil structure, which helps to maintain the pores, is very
dynamic and may change greatly from time to time in response to changes in
natural conditions, biological activity and the soil-management practices.
Repeated cycles of wetting and drying and freezing and thawing help to form
peds, while plants with extensive root systems and soil fauna activity promote
soil aggregation and channeling. On the other hand, mechanical compaction
and the dilution of soluble salts can cause the breakdown of the peds, reducing
the capacity of the soil to conduct water.
Characterization of Water in Soils—
Under naturally drained conditions, some pores in soil are filled with
water. The distribution of this water depends upon the characteristics of the
-3U-
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basic structure
basic structure
skeleton grains
plasma
| [ voids
interpedal planar voids
mtrapedal
vugh
FRAGMENT OF APEDAL
SOIL MATERIAL
PEDAL SOIL MATERIAL
1 cm
1 cm
Figure 5. Schematic representation of a single-grained (left) and an
aggregated soil material (right) (Bouma, et al. 1972).
pores while its movement is determined by the relative energy status of the
water. Water flows downhill, but more accurately, it flows from points of
higher potential energy to points of lower potential energy. The energy status
is referred to as the moisture potential.
The total moisture potential ¥^ in soils may be defined as:
where Vm, ¥_, f , ¥ and ¥^ are the matric, gravity, pressure, osmotic and over-
burden potentials, respectively. Of these, the matric, gravity and pressure
potentials are the most significant in soil absorption of wastewater.
The gravitational potential ¥g is the result of the attraction of water
toward the center of the earth by a gravitational force and is equal to the
weight of the water. To raise water against gravity, work must be done and this
work is stored by the water in the form of gravitational potential energy.
The potential energy of the water at any point is determined by the elevation
of that point relative to some reference level. Thus, the higher the water,
the greater its gravitational potential.
The matric potential,
is produced by the affinity of water to the soil
particle surfaces. The pores and surfaces of soil particles hold water due to
-35-
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forces produced by adhesion and cohesion. Individual molecules within the
liquid are attracted to other molecules equally in all directions by cohesive
forces. Molecules at the surface of the liquid, however, are attracted more
strongly by the liquid than by air. To balance these unequal forces, the sur-
face molecules pull together causing the surface to contract creating surface
tension. When solids come in contact with the surface of the liquid, the water
molecules are attracted to the solid. If a small tube is placed vertically
in the water, the water will climb up the surface of the solid. This is
referred to as capillary rise. The upward movement ceases when the weight of
the raise water equals the force of attraction between the water and the solid.
Of course, this phenomenon operates to move water in all directions.
As the ratio of solid surface area to liquid volume increases, the
capillary rise increases. Therefore, water rises higher in smaller pores.
For example, a cylindrical pore radius of 100 microns corresponds with a rela-
tively low capillary rise of 28 cm water (pressure below meniscus equals -28
cm water) while a pore radius of 30 microns results in a relatively high rise
of 103 cm (pressure equals -103 cm water). The water within the tube is at
less than atmospheric pressure as noted because it is "pulled" downward by
gravity as it is being "pulled" upward by the forces of capillarity. The water
is under tension as the tube essentially "sucks" the water into it. This
negative pressure in soil is called soil tension or soil suction and is measured
in millibars (mbar). This implies that it takes more energy to remove or pull
water from a small pore than a large one (Figure 6).
In addition to the capillary phenomenon, adhesive forces also contribute
to the matric potential. Molecular forces between the surface of the soil
particles and the water form envelopes of water over the particle surfaces
retaining the water in the soil (Figure 6).
When the soil is saturated, all the pores in the soil are filled with
water and no capillary suction occurs. The soil moisture tension or matric
potential, therefore, is zero. If the soil drains, the largest pores empty
first, because they have the least tension to hold water. As drainage con-
tinues , progressively smaller pores empty and the soil moisture tension increases
because smaller pores have a stronger pull to hold water. Thus, the tension
represents the energy state of the largest water filled pores. With further
drainage, only the very narrowest pores and solid surfaces are able to exert
sufficient "pull" to retain water. Hence, increasing tension or suction is
associated with drying.
The rate of decrease of moisture in soil upon increasing tension is a
function of its pore-size distribution, and is characteristic for each soil
material or type. Figure 7 shows the soil moisture retention curves for a sand,
silt loam, sandy loam and a clay soil. The sand has many relatively large
pores that drain abruptly at relatively low tensions, whereas the clay releases
only a small volume of water over a wide tension range because most of it is
strongly retained in very fine pores. The silt loam has more coarse pores
than does the clay, so its curve lies somewhat below that of the clay at higher
tensions. The sandy loam has more fine pores and fewer coarse pores than the
sand so its curve lies above that of the sand after initial drainage has occurred.
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SOIL PARTICLE
CAPILLARY WATER
ADSORBED WATER
Figure 6. Upward movement by capillarity in glass tubes
as compared with soils (after Brady, 197*0-
20 40 60 80 100
SOIL MOISTURE TENSION (MBAR)
Figure 7- Soil moisture retention for four different soil
materials (Bouma, et al. 1972).
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The pressure potential is due to the weight of water at a particular
point. If the point is beneath the water table, pressure potential is equal
and opposite to the gravity potential that is measured from the free water
surface. If the point is above the free water surface, the pressure potential
is zero.
Liquid Movement in Soils—
Water will flow from a point where it has a higher energy potential to
a point where it has a lower energy potential. In unsaturated soils, the gravity
and matric potentials are the only significant components of the total energy
potential since the pressure potential is zero. The gravity potential acts to
move water vertically downward, while the matric potential acts to move water
in all directions. In saturated soils, the pressure potential is analogous to
the matric potential, now zero, in unsaturated soils. The rate of flow in-
creases as the potential difference or potential gradient between points in-
creases. The ratio of the flow rate to the potential gradient is referred to
as the hydraulic conductivity or K defined by Darcy's Law.
Q = KA dY
dZ
where: Q = flow rate
K = hydraulic conductivity
A = cross-sectional area of flow
df = hydraulic gradient
dZ
The hydraulic conductivity, K, accounts for all the factors affecting flow
within the soil including tortuosity and size of the pores. Thus, the
measured K values for different soils vary widely due to differences in pore
size distributions and pore continuity.
The hydraulic conductivity often changes dramatically with changes in the
soil moisture tension. At a tension equal to or less than zero, the soil is
saturated and all the pores in the soil are conducting liquid. When the tension
is greater than zero, air is present in some of the pores and unsaturated con-
ditions prevail. This condition grossly alters the flow channel or cross-
sectional area, A, because the forces which cause flow are now associated with
capillarity. As the water content decreases or tension increases, the path of
the water flow becomes more and more tortuous since the water travels along
surfaces and through sufficiently small pores to retain water at the prevail-
ing moisture tension. Therefore, the unsaturated hydraulic conductivity is
usually much lower.
To illustrate this, three different soil materials can be considered with
pore size distributions schematically represented in Figure 8. One "soil"
is a coarse, porous material (like a sand), one is a fine porous material (like
a clay) and a third (like a sandy loam) has both large and fine pores. With
an open infiltrative surface and with a sufficient supply of water, all the soil
pores are filled and each pore will conduct water downward due to gravity.
The large pores will conduct much more water than the smaller ones. If a weak
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v •
I '
n
Very low
{ t
or
Strong
muMBftimM^
-4
•*
Rate of application
of liquid
Degree of crusting'
SAND
LOAMY SAND
SANDY LOAM
SILT LOAM
(Liquid
f~~j Crust
CLAY
Figure 8. Schematic illustration of the effect of increasing crust
resistance or decreasing rate of application of liquid
on the rate of percolation through three "soil materials"
(Bouma et al., 1972).
barrier or crust forms over the tops of the tubes to restrict flow, some of
the larger tubes will drain. Only the pores with sufficient capillary force
to "pull" the water through the crust will conduct water. The larger the
pore, the smaller the capillary'force so that progressively smaller pores
empty at increasing crust resistance. This crusting leads to a dramatic
reduction in the hydraulic conductivity of the soil (Figure 8).
If no crust is present, similar phenomena occur when the rate of appli-
cation of water to the soil is reduced. With abundant water supply, all pores
are filled. If the supply is decreased, there is not enough water to keep
all pores filled during the downard movement of the water. The larger pores
empty first, since the smaller pores have a greater capillary attraction for
water. Thus, larger pores can fill with water only if smaller pores have an
insufficient capacity to conduct away all the applied water.
The reduction in K upon increasing soil moisture tension, therefore, is
characteristic for a given soil texture and structure. Hydraulic conductivity
or K curves, determined in situ show such patterns for natural soil (Figure 9)-
Coarse soils with predominantly large pores have relatively high saturated
hydraulic conductivities (Ksat), but K drops rapidly with increasing soil
-39-
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moisture tension. Fine soils with predominantly small pores have relatively
low K
sat1
but their hydraulic conductivity decreases more slowly upon
increasing tension.
The K curves for the pedal silt loam and clay horizons demonstrate the
physical effect of the occurrence of relatively large cracks and root and worm
channels. The fine pores inside peds contribute little to flow. The large
pores "between peds and root and worm channels give relatively high Ksa-t values
(25 cm/day for the silt loam), but these pores are not filled with water at
low tensions and K values drop dramatically between saturation and 20 cm
tension (1.5 cm/day for the silt loam).
1000 —
_ 100 —
o
10-
o
O
a
o
o
o
_J
1.0-
0.1-
245 -
20 40 60 80 100
SOIL MOISTURE TENSION (MBAR)
DRYING ^
Figure 9- Hydraulic conductivity (K) as a function of soil moisture
tension measured in situ with the crust-test procedure
(Bouma, 1975).
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Liquid Movement Into Soils
When liquid wastes are applied to the soil, a clogging zone often develops
at the infiltrative surface. This restricts the rate of infiltration,
preventing saturation of the underlying soil even though liquid is ponded
above. The soil is then able to conduct liquid only if the water is able to
penetrate the clogged zone under the forces of hydrostatic pressure and capil-
lary pull.
The Process of Pore Clogging—
Several phenomena contribute to the development of a clogging zone at
the infiltrative surface of soil absorption systems. These include: 1) pud-
dling caused by the constant soaking of the soil during operation, 2) blockage
of soil pores by solids filtered from the waste effluent, 3) accumulation of
biomass from growth of microorganisms, h) excretion of slimy polysaccharide
gums by some soil bacteria, 5) deterioration of soil structure caused by ex-
change of ions on clay particles, and 6) precipitation of insoluble metal sul-
fides under anaerobic conditions.
This description of soil clogging assumes that the native soil structure
is left relatively intact at the infiltrative surface during construction of
the system. However, many systems fail, usually within a year or two, because
of poor construction techniques. Absorption of water by soils depends upon
preservation of a suitable soil structure, but soil structure can be partially
or completely destroyed by compaction and smearing during construction.
Extensive damage does not occur in soils with a single-grained structure (sands),
but can be very serious in aggregated soils with high clay contents. When
mechanical forces are applied to a moist or wet soil, the water around clay
particles acts as a "lubricant" causing the soil to exhibit plasticity where
individual particles move relative to one another. Such movements, referred
to as compaction, puddling, or smearing, close the larger pores. The potential
for structural damage of this type increases as soil wetness and clay content
increase. Compaction may result from frequent passes over the field by heavy
machinery, smearing of the soil surface by excavating equipment and puddling
by exposure of the infiltrative surface for a day or more to rainfall that
seals off the soil pores. The result is that the absorption field may be clogged
before it is put into service.
Studies by several investigators indicate that the physical and biological
mechanisms are the primary causes of soil clogging in an absorption field not
smeared and compacted during construction (Bendixen, et al. 1950; Bouma, et al.
1972; de Vries, 1972; Laak, 1970; McGauhey and Krone, 1967; McGauhey and
Winneberger, 196U; Weibel, et al. 195^). In these instances, clogging seems to
develop in three stages: l) slow initial clogging, 2) rapid increase of
resistance, leading to permanent ponding, and 3) a final leveling off towards
equilibrium. During initial development of the clogging zone, the liquid seeps
away more and more slowly between loadings. Aerobic bacteria decompose many
of the organic solids, helping to keep the soil pores open, but they can
function only when the infiltrative surface drains between doses to allow the
entry of air. As the clogging zone begins to form, decreasing the aerobic
periods between ponding, the aerobic bacteria eventually are unable to keep up
-in-
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with the influx of solids. Permanent ponding finally results, leading to
anaerobic conditions where oxygen is no longer present. Any dissolved oxy-
gen in the water is inadequate to maintain the aerobic environment necessary
for the rapid decomposition of the organic matter. Clogging then proceeds
more quickly due to the less efficient destruction of soil clogging organics
by anaerobic bacteria. Sulfides produced by reduction of sulfate by these bac-
teria bind up trace elements as insoluble sulfides, causing heavy black
deposits in the clogging zone. Some anaerobic and facultative organisms,
which grow in such an environment, produce gelatinous materials (bacterial poly-
saccharides, slimes, or gums), which clog the soil pores very effectively.
At this point, the clogging mat seems to reach an equilibrium state where the
resistance to flow changes little.
The Significance of Soil Clogging—
Because of the barrier to flow created by soil clogging, the soil below
the clogged area becomes unsaturated. This is very significant when waste-
water is applied to the soil for disposal. Flow of liquid in unsaturated soil
proceeds at a much slower rate than in saturated soil, because flow only
occurs in the finer pores. This slows the rate of infiltration into the soil,
but enhances purification. Wastewater effluent is purified by filtration,
biochemical reactions and adsorption processess which are more effective in un-
saturated soils because average distances "between efffluent particles and the
soil particles decrease, while the time of contact increases. This flow
phenomenon can be illustrated by an example (Bouma, et al. 1972). Figure 10
shows a thin section of the C horizon of a Saybrook silt loam, which is a stony
sand loam till with a saturated hydraulic conductivity of 80 cm/day. The flow
velocity of water in the soil pores can be estimated knowing the percent of
water filled pores at different moisture potentials as given by its moisture
retention curve (Figure 7). This velocity can be used to derive the time for
water to travel one foot (30 cm), assuming a hydraulic gradient of 1 cm/cm due
only to gravity. Successively smaller pores empty at increasing tensions
and K decreases correspondingly (Figure 9). Calculated travel times increase
from 3 hours at saturation to 30 hours at 30 mbars and 8 days at 80 mbars of
soil moisture tension.
In structured soils it is possible to have flow predominantly through the
planar voids, thus bypassing the interior of the peds. High liquid applications
may result in high dispersion where the water passes through the planar voids
without displacing the water already in the peds. In such instances, short
circuiting of liquid through the soil occurs with associated lower retention
times. Lower application rates would displace more of the water in the peds and
reduce dispersion. Differences in dispersion related to different soil
structures have been noted in lysimeter studies of chloride movement in soil.
The soil columns indicated a short circuiting to be a particular problem on
drained soils dosed at relatively high rates (Anderson and Bouma, 1977a and
1977b).
Short circuiting in a structured soil is schematically illustrated in
Figure 11. If the large planar voids are drained and air filled, a high
application rate of liquid applied at the surface will quickly pass through
the large pores before much can enter the fine pores of the peds. Therefore,
-H2-
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jfj Skeleton grams
Plasma
(very porous
and calcareous)
SAYBROOK SILT LOAM (IIC STONY SANDY LOAM TILL)
SATURATED
K= 80 cm/day
ONE FOOT (30 cm ) MOVEMENT IN THE SOIL IN
(hydraulic gradient 1cm/cm)
At 30 mb. SUCTION
K » 7 cm/day
30 hours
At 80 ab. SUCTIOM
K » T mm/day
8 days
Figure 10. Occurrences and movement of liquid in a saturated
and unsaturated sandy loam till C horizon of
Saybrook silt loam (Bouma, et al. 1972).
channeling occurs where the retention time of the bulk of the liquid is low
and only a portion of the entire soil volume is used to transmit the fluid.
If the application rate is low or if there is a barrier to flow, such that the
soil remains unsaturated, the dispersion is low. The large pores will not
fill with liquid and flow will be through the finer pores within the peds.
In this case, the retention time will be longer and flow will be primarily
through the portion of the soil most effective in renovation.
Long liquid travel times are desirable to adequately purify the waste-
water. The design of absorption systems may be critical to achieve this in
some soils. Travel times are sufficiently long under all moisture tensions to
effect adequate purification in clay, but are too short in sand and sandy loams
when the soil is near saturation. Once a clogging zone has developed in such
permeable soils, the hydraulic conductivity is reduced to a level where suf-
ficiently long travel times result. However, when an absorption system con-
structed in a highly porous or dry structured soil is first put into .service
without a developed clogged zone, adequate purification may require an increased
depth of soil unless precautions are taken in design to insure unsaturated
soil conditions are maintained.
-1*3-
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UNCLOGGED
CLOGGED
ADDED WATER
CLOGGING ZONE
Figure 11. Influence of clogging zone on short
circuiting in structured soils.
Factors Effecting Soil Clogging —
Dosing and resting — There is substantial evidence that continuous ponding
of wastewater on the soil's infiltrative surface leads to more severe clogging
than if the clogging mat were to remain at least intermittently aerobic (Ben-
dixen, et al. I960; Winneberger, et al. I960; and Thomas, et al. 1966). To
provide reaeration, periods of loading are followed by periods of resting with
cycle frequencies ranging from hours to months. The resting phase allows the
soil to drain and reaerate, thus encouraging rapid degradation of the
clogging mat. This operation may extend the life of an absorption system or
reduce the infiltrative surface area by keeping the clogging mat resistance
to a minimum.
Early laboratory work with lysimeters showed repeatedly that reduction in
the infiltrative capacity of the soil proceeds more slowly when periods of
ponding were alternated with periods of aeration (Bendix, et al. 1950; Winne-
berger, et al. I960; and Thomas, et al. 1966). Contrary to these findings,
Kropft, et al. (1975; 1977) report that total flow through the clogging mat
remained higher in constantly ponded soil columns than in columns subjected to
intermittent flooding. Similar results were obtained in this study when com-
parisons were made between soil columns aerated below the infiltrative surface
and those that were not (Perry and Harris, 1975; Jawson, 1976). The aerated
columns showed that effluent application regimes characterized by short term
alternating anaerobic-aerobic conditions may result in reduced infiltration
associated with the formation of an intense clogging during the aerobic resting
phase. Once clogged, restoration of the infiltrative surface by resting
requires at least three to four weeks in sands (Perry and Harris, 1975). The
required resting period may be longer in finer textured soils .
-uu-
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These results may not be as contradictory as they first seem. The oxi-
dation-reduction potential in and around the clogging mat may be critical to
maintaining high infiltration rates. Initially, cycles of dosing and resting
maintain higher redox potentials in the soil than continuous ponding, which
retards the development of the clogging mat. However, if clogging is allowed
to proceed, the organics accumulated during periods of dosing may be too great
for complete aerobic digestion during the resting phase. With an ample food
supply, the aerobic and facultative organisms rapidly convert the clogging
agents to new cell mass and slime which become new clogging agents. To prevent
this, longer periods of aeration or more uniform distribution may be necessary
to realize any benefits of dosing.
The laboratory results have not yet been validated in the field. Limited
data from existing dosing systems indicate that the mechanisms may be even more
complex than indicated. Bouma, et al. (1975&) and the University of Wisconsin
reported that a system constructed in a silty clay loam soil with a percolation
rate of 12 min/cm (30 min/inch) was still operating satisfactorily when dosed
once daily at a loading rate one-third that recommended by the Manual of Septic
Tank Practice (U.S. Public Health Service, 1967). When excavations were made
to determine the extent of clogging, evidence of worm activity was observed in
the clogging mat which seemed to reopen the infiltrative surface. This
activity could only occur during periods when the soil is not ponded. More field
work is necessary to determine optimum cycles of dosing and resting.
Applied wastewater quality—It is reasonable to assume that improving the
wastewater quality before application to the soil would inhibit clogging.
However, in several column studies investigating the effects of effluent clog-
ging on soil infiltration, only slight differences in clogging rates were found
over a broad range of wastewater qualities.
In studies with undisturbed cores of Almena silt loam (percolation rates
of 70 min/inch in the topsoil and 100 min/inch in the subsoil) columns were
continuously ponded with septic tank effluent, aerobic unit effluent and dis-
tilled water (Daniel and Bouma, 197^). The aerobic effluent had a significantly
lower biodegradable organic concentration than the septic tank effluent (chemi-
cal oxygen demand concentrations of 60 mg/L and 150 mg/L respectively, but
the suspended solids concentrations were similar (33 mg/L and hO mg/L res-
pectively). More severe clogging occurred with the aerobic effluent. No clog-
ging occurred in the soil loaded with distilled water. It was hypothesized
that finely divided suspended solids in the aerobically treated wastewater
were able to enter the small pores in the soil, clogging the soil with depth
and creating a more effective barrier to flow.
Subsequent studies designed to test the solids clogging hypothesis,
indicated that the initial saturated hydraulic conductivity is more signifi-
cant than effluent quality. Undisturbed cores of Almena silt loam were
paired according to their initial saturated hydraulic conductivity, one pair
representing a high and low initial Ksa-^. Three sets of four replicates each
were dosed with 1 cm/day of septic tank effluent (U8 mg/L BODr, 28 mg/L TSS),
aerobic unit effluent (27 mg/L BOD5, 6l mg/L TSS), and tap water. The length
of time to when each column remained ponded between daily doses was recorded.
-------
The aerobic columns showed mean ponding times of 21,3 weeks, the septic tank
set 20.6 weeks, and the tap water 18.3 weeks. When initial Ksat values were
compared between all three sets, the ponding times for the high KSat columns
was 28 weeks while the ponding times for the low Ksa-t was lU.8 weeks.
These studies seem to indicate that, in fine texture structured soils,
applied effluent quality does not affect the rate of clogging. The sand filter
studies, however, suggest that improved quality may reduce the degree of
clogging in coarse granular soils.
Infiltration Rates Through Clogged Surfaces—
If the soil's ability to accept liquid during wastewater application is
to "be accurately predicted, consideration of unsaturated flow phenomena due to
soil clogging mats or compaction is essential. Clogging mats or compacted soil
layers of progressively higher resistances will allow progressively lower
rates of infiltration through the soil.
Infiltration is not only dependent upon the resistance of the clogging
zone, but also on the hydrostatic pressure of the ponded water above the
clogging layer and the capillary properties of the underlying soil (Bouma,
19T5). For example, an identical "crust" with a resistance of 5 days (the
length of time for 1 cm3 to pass through 1 cm^ of barrier with a head of 1 cm)
ponded with 5 cm of liquid, would induce flow rates of 8 cm/day in a sandy
loam; 7 cm/day in a sand; k cm/day in a silt loam; and 1.8 cm/day in a clay.
"Crusts" with very high resistances would conduct more liquid when overlying
a clay than when overlying a sand. Thus, if similar clogging zones developed
in different soils, they would have different conductivities. This fact may
effect clogging mat development and its ultimate resistance.
The hydraulic conductivity, which is the one-dimensional flow rate
through a unit area under a unit hydraulic gradient, is a reliable measure or
any saturated or unsaturated soil to accept and conduct liquid. Figure 9 pre-
sents the general K-curves developed for the major textural groupings in
Wisconsin. These curves relate K to the soil moisture tension. Continued
research may result in different groups at a later date. Through the use of
tensiometry, the soil moisture potential and gradient around soil absorption
beds can be measured in situ with little disturbance of the soil. Thus, the
moisture potential and its gradient measured in situ can be translated into a
flow rate by using Darcy's Law (Bouma, 1975).
Moisture potentials were measured under several ponded conventional
septic tank-soil absorption systems to determine equilibrium flow rates through
clogging mats in different soils (Bouma, 1975; Bouma, et al. 1972; 1975&;
Magdoff and Bouma, 197^; Walker, et al. 1973&). Small excavations were made
adjacent to ponded systems and the tensiometers were installed at different
points in the soil below and to the side of the systems. Measured potentials
were used to estimate infiltration rates into the soil through the bottom
and the sidewalls of the system, using the appropriate K-curve (Figure 9). A
summary of the results is presented in Table 23.
Conductivity type I (sands)—Results of monitoring systems installed in
sands showed that moisture tensions and associated flow rates in soil
-U6-
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surrounding clogged trenches or beds were not very different for different
systems, despite differences in system age. This would indicate that a
mature clogging mat is established early in the system's life and that flow
rates through the mat change little as the system ages. The results also show
that clogged sands accept significant quantities of septic tank effluent through
both bottom and sidewall surfaces.
Based on these data, 5 cm/ day (1.2 gpd/ft2) is recommended as a maximum
loading rate of the bottom area for systems with 30-cm (12 in) sidewalls
constructed in sands (Bouma, 1975). It is further recommended that the efflu-
ent be applied uniformly over the entire bottom infiltrative surface in four
or more daily doses, particularly during system start-up, if bacterial and
viral contamination of a shallow water table is a concern. The uniform appli-
cation in small volumes will insure unsaturated conditions in the sand necessary
for good purification.
Conductivity type II ( sandy loams , loams ) — Soils of this type have rapid
percolation rates initially, but they have a tendency to clog quite severely.
This may be due to their particular pore size distribution and structural in-
stability. Relatively low clay contents do not allow significant swelling and
shrinking of the soil necessary to form structural units or peds with associated
interpedal cracks. Tubular worm and root channels are formed, but they tend
to be more unstable and much less permanent than those formed in clayey soils.
Thus, the packing pores between particles, which are much finer than in the
sands, are the principal voids through which the water moves (Bouma and
Anderson, 1973). The finer pores may result in greater accumulation of solids
at the infiltrative surface and the development of anaerobic conditions in the
clogged layer due to the reduced air diffusion compared to sandy soils (Magdoff,
et al.
The moisture tensions measured below the bottom of the systems increased
with increased ponding depth within the systems. The estimated rates through
the bottom areas varied from 0.^ cm/day (0.09 gpd/ft2) to 1.9 cm/day (O.h5 gpd/
ft2). The estimated rates through the sidewalls were similar.
To maintain reasonable infiltration rates, the data suggest that ponding
levels within the system should be kept to a minimum. To reduce ponding
levels, intermittent periods of aeration between applications should be provided
to allow aerobic decomposition of the clogging mat. To test this hypothesis,
one system was drained and allowed to dry before wastewater was reapplied in
once per day dosings. After several months of operation in this mode, the
moisture tensions below the clogging mat had dropped from 80 mbar to 60 mbar,
indicating the mat was passing more liquid. When the operation returned to
continuous application, the moisture tensions again increased to 80 mbar
(Bouma, et al. 1972).
Absorption fields designed for bottom area loadings of 3 cm/day (0.7 gpd/
ft2) with 30-cm (12-in) sidewalls have functioned well in Wisconsin. Trenches
are preferred to beds, with once daily dosing recommended if this rate is used
(Bouma, 1975). This rate is somewhat lower than design rates used elsewhere.
-1*7-
-------
Conductivity type III (silt loams, some silty clay loams)—Although
these soils are more finely textured than either Type I or Type II soils,
their more strongly structured nature can maintain relatively high infiltra-
tion rates if the system is constructed and managed properly. The cause of
many failures can "be traced to construction problems (Bouma, 1975; Bouma, et al.
1975a). Construction of beds often involves several passes over the infil-
trative surface by machinery while excavating and placing of the rock. This
practice can result in severe compaction and puddling if the soil is wet,
because these finer textured soils exhibit a plastic consistency over a wide
range of moisture contents, which occur naturally in the field (Bouma, 1975).
Observations made at some installations indicated that excavating equipment
had been driven over the bottom areas of the beds during construction. The
presence of a compacted layer was confirmed by moisture tension measurements
taken below the beds. These indicated a restricting layer with a resistance
reasonbly close to resistances through layers of manually puddled fine silty
soil materials (Bouma, et al. 1971; Bouma, et al. 1975a). Other systems studied,
which were functioning satisfactorily, did not contain ponded effluent. Samples
taken of the soil from the bottom of the systems showed well exposed soil
structure with open planar voids between peds as well as worm and root channels.
The exposure of these larger pores explains the lack of ponding. This points
to the importance of construction practices which minimize damage to the
structure of the soil.
Dosing and uniform distribution, with drying periods under aerobic con-
ditions between applications, may stimulate worm and other fauna activity,
as organisms seek the nutrient deposited at the infiltrative surface. Such
activity can leave relatively large open channels through the clogging mat.
This would seem to suggest that while good construction practices are necessary
to expose an open infiltrative surface, periodic application of effluent is
essential to keeping the surface open.
While the data are not conclusive, they suggest that maximum permissible
loading rates would vary according to the method of distribution employed.
If once daily dosing were employed, maximum rates of 5 cm/day (1.2 gpd/ft^)
might be acceptable based on bottom area only (Bouma, 1975). Uniform distri-
bution would be crucial in this case to maintain unsaturated flow so that deep
penetration of pollutants through the large exposed pores will not occur.
If conventional gravity trickle distribution is used, the conventional loading
rate of 2 cm/day (0.5 gpd/ft2) should not be exceeded. In both cases, shallow
trench designs ^5 to 60 cm (l8 to 2U in) deep are preferred because the upper
soil horizons are usually more porous and less subject to damage during con-
struction. Shallow systems also enhance evapotranspiration.
Conductivity type IV (clays, some silty clay loams)—Low conductivities
in these soils at saturation drop strongly in the 0 to 20 mbar tension range
due to the emptying of the interpedal voids and tubular channels as in
Type III soils. However, lower Ksa/t values indicate the lack of many large
pores. Thus, the soil itself, rather than the clogging mat, becomes the domin-
ant controlling factor (Bouma, 1975; Healey and Laak, 197*0 •
-U8-
-------
Because soils of this type have severely limiting hydraulic properties,
it may "be more crucial to maintain an open infiltrative surface to utilize
the large interpedal cracks and tubular channels. Dosing frequencies of once
per day or longer may promote soil fauna activity "between dosings to maintain
an open surface (Bouma, et al. 1975a). If conventional gravity distribution
is used, loading rates of 1 cm/day (0.2 gpd/ft2) based on the bottom area only
would seem to be acceptable, assuming 33 percent of the flow would be through
the sidewall (Bouma, 1975). If expandable clays are present, a lower rate
should be used.
TABLE 23. RECOMMENDED MAXIMUM LOADING RATES FOR SEPTIC
TANK SOIL ABSORPTION FIELDS BASED ON IN SITU
MEASUREMENTS! (After Bouma, 1975)
Conductivity
Type
Soil Texture
Loading
Rate2 cm/day
(gpd/ft2)
Operating Conditions
II
III
IV
Sand
Sandy Loams
Loams
Silt Loams 5 (1.2)3
Some Silty Clay Loams
Clays
5 (1.2) h doses/day
Uniform Distribution
Trenches or Beds
3 (0.7) 1 dose/day
Uniform Distribution
Trenches Preferred
2 (0.5) Conventional Distribution
Shallow Trenches
1 dose/day
Uniform Distribution
Shallow Trenches Only
1 (0.2)3 1 dose/day
Uniform Distribution Desirable
Shallow Trenches Only
Assumes that the high water table is > 90 cm (3 ft) below the infiltrative
surface.
2
Bottom area only
Should not be applied to soils with expandable clays.
WASTEWATER TREATMENT CAPABILITIES OF SOILS
The principal goal in soil disposal of liquid wastes for homes in unsewered
areas is the purification of the liquid before it reaches surface or ground
waters. Organic matter, chemicals and pathogenic organisms and viruses that
are not removed prior to application to the soil must be removed or transformed
-49-
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by the soil material. Numerous studies have shown that under proper
conditions, the soil is an extremely efficient purifying medium. More de-
tailed discussion on this topic can be found in Appendix C.
The Fate of Bacteria and Viruses in Soils
From the standpoint of public health, the removal of potential pathogenic
organisms and viruses is the most critical function of a soil absorption
system. Many field and laboratory studies have examined the efficiency of the
soil for pathogen removal and the various parameters that affect its efficiency.
Factors important in removal of pathogens by soil include soil type, tempera-
ture, pH, organism adsorption to soil and soil clogging materials, soil
moisture and nutrient content and biological antagonisms (Gerba, et al. 1975).
Another key factor is the liquid flow regime in the soil. As shown previously,
unsaturated flow, induced by either a clogged zone or application rate, enhances
purification because liquid movement is primarily through only the smaller
pores of the soil forcing greater liquid-soil contact.
Figure 12 shows removal of fecal coliforms and fecal streptococci from
septic tank effluent by two columns packed with 60 cm (2 ft) of Plainfield
loamy sand (effective size O.lU mm, uniformity coefficient 1.99) (McCoy and
Ziebell, 1975; Ziebell, 1975). Both columns were loaded well below their
saturated hydraulic conductivity rates of nearly UOO cm/day (96 gpd/ft2), but
one was loaded at twice the rate of the other. During the first 100 days of
application, the number of bacteria discharged from both columns reached
a plateau and then began to decline. Fewer bacteria passed through the column
with the lower loading rate. Column 1, loaded at 10 cm/day (2.U gpd/ft2),
removed approximately 92 percent of the fecal coliforms applied per day while
column 2, loaded at 5 cm/day (1.2 gpd/ft2), removed 99.9 percent. Fecal
streptococci and Pseudomonas aeruginosa were also found in the effluent from
the more heavily loaded column 1. These organisms were not detected in efflu-
ent from the more lightly loaded column 2. During this period a clogging zone
developed on the infiltrative surface of each column and the fecal coliform
count in the effluents from both columns eventually dropped to between 10 and
100 FC/100 mL (McCoy and Ziebell, 1975)-
Septic tank systems installed in sands also exhibit the effects of the
clogging zone in removing indicator bacteria. Figure 13 shows the bacterial
counts obtained while monitoring several points around an absorption trench in
an unsaturated medium sand soil. The kinds and numbers of bacteria found in
the liquid 1 foot (30 cm) below and 1 foot (30 cm) to the side of the trench
were similar to natural soil flora (Bouma, et al. 1972; McCoy and Ziebell, 1975;
Ziebell, 1975)-
Concurrent studies of Almena silt loam were also conducted (Ziebell,
1975). This soil has a lower capacity to conduct liquid than the unstructured
sands and the majority of flow is through the larger pores between soil peds.
Undisturbed cores, 60 cm (2 ft) deep, of Almena silt loam were loaded with
septic tank effluent at a rate of 1 cm/day (0.2U gpd/ft2). At this loading,
with no clogging mat present, effluent short-circuited through large pores
and channels in the soil and significant numbers of bacteria were found in the
column effluents. When the loading rate was reduced to 0.3 cm/day to promote
flow through the soil peds rather than through the larger cracks around the
peds, counts decreased dramatically to below 2/100 mL of fecal coliforms,
-50-
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CO
^ T
o
o
-x 5
<
o: 4
COLUMN I
0-0
CO
O
< 4
tr
£ 3
o '
3
COLUMN 2
20
60
100
140
180
TIME (days)
Figure 12. Bacteria counts in effluents from sand columns loaded
with septic tank effluent. Column 1 loaded at 10 cm/
day (l.5 hours retention time) and Column 2 loaded at
5 cm/day (25 hours retention time). FC = fecal coli-
forms; FS - fecal streptococcus (Ziebell, 1975)-
fecal streptococcus and JP. aeruginosa (Figure lU). When the loading was
restored to 1 cm/day, high counts of these organisms were again observed.
Virus adsorption and inactivation in soils have been of considerable inter-
est to scientists and engineers over the years. When viruses enter the septic
tank or other treatment process, they are likely associated with cells in
fecal material. These solids settle, but they may release some viruses depend-
ing upon turbulence within the process. Secondary adsorption on wastewater
solids may occur in treatment processes but some free and particle adsorbed
viruses will be discharged to subsequent treatment processes or to the soil
absorption field.
Eemoval of viruses in soils occurs as the result of the combined effects
of sorption, inactivation and retention. Upon entry into the soil, viruses
are rapidly adsorbed to solid surfaces. Desorption appears to be strongly
related to the ionic strength of the applied fluid, increasing as the ionic
strength decreases (Lance, et al. 1976). In the adsorbed position, the
-51-
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3 -
ABSORPTION FIELD
CROSS SECTION
FT
o
1 -
-
2 -
TRENCH
O
7
1
LIQUID *
-. FT-H ^
BACTERIA/100 MLS OR PER 100 6 OF SOIL
FECAL FECAL TOTAL TOTAL
STREPTO- COLIFORMS COLIFORMS BACTERIA
COCCI xlO7
NATURAL
SOIL
<200
<200
<200
<2OO
<200
<600
17,000
<200
700
23,000
<600
1,800
0.6
160,000 1,900,000 5,700,000 3.0
54,000 4,000,000 23,000,000 4,400
6.7
3.7
2.8
Figure 13. Cross-section of seepage trench in sand
showing bacterial counts at various points
near the trench (Ziebell, 1975).
the viruses are inactivated in a spontaneous process which is temperature
dependent, "being greater at the higher temperatures (Green, 1976). Virus
detention within the soil is affected by the degree of saturation of the
pores through which the virus laden effluent flows. The more saturated the
pores, the less opportunity there is for virus contact with surfaces to
which it can adsorb.
In laboratory studies with packed sand columns, septic tank effluent was
inoculated with more than 10^ plaque-forming units (PFU) per liter of polio-
virus type 1 (Green, 1976; Green and Oliver, 197^). All viruses were removed
in the columns at a loading rate of 5 cm/day (1.2H gpd/ft2) applied in single
doses over a period of more than one year. At a loading rate of 50 cm/day
(12.H gpd/ft2), virus breakthrough occurred (Figure 15). Analysis of the
sand residue following virus application, indicated that adsorbed viruses
within the column were inactivated at a rate of 18 percent per day at room
temperature and at 1.1 percent per day at 6 to 8°C (Green and Oliver, 197M •
Laboratory tests with ground soil material from a Batavia silt loam
reduced virus in septic tank effluents by 5.^ logs per cm of depth and
Almena silt loams material produced 7-9 logs of reduction per cm (Green and
Oliver, 197H). It should be emphasized, however, that soils in the field do
not exist in a finely ground state. Channels in natural soil will reduce
opportunity for virus adsorption and travel over long distances may occur
when loading rates are high.
It would appear from these studies that sandy soils without structure,
loaded at 5 cm/day (l.2U gpd/ft2) or less, should adequately remove bacteria
-52-
-------
CO 81-
_l
5 7 -
§6L
^ 5
<
CC 4
UJ
O
O
PC
•• * •I'-'-L'* *\
20 60
rT ' ',
100 140
§
•H"0^.
r -"S
L —
180 g.
Figure
TIME (days)
Bacteria counts in effluent from an undisturbed
core of Almena silt loam loaded with septic tank
effluent (Ziebell, 1975).
and viruses within 60 cm (2 ft). In structured soils with no clogging mat
present, lower loading rates are required to achieve purification within
60 cm (2 ft). In clogged soils where infiltration rates are limited by the
clogging mat, loading rates are less critical unless surfacing of effluent
occurs due to excessive applications.
The Fate of Nutrients in Soils
Domestic wastewaters may contain chemicals hazardous to public health or
the environment. Nitrogen and phosphorus compounds are discharged in house-
hold wastewater which can enter ground or surface waters in sufficient quanti-
ties to cause concern. Nitrogen, in the form of nitrate or nitrite has been
linked to cases of methemoglobinemia in infants (Groundwater Contamination,
196l). A safety limit for nitrate of 10 mg/L as nitrogen is recommended by
the U.S. Public Health Service (Gruener and Shuval, 1969). There are many
reports of nitrate concentrations above 10 mg/L-N limit in wells near
septic tank systems (Dudley and Stephenson, 1973; Preul, 196^; Walker, et al.
1973b; Ground wat er Cont aminat i on , 1961).
-53-
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log^PFU/ml)
01 23456
Figure 15- Penetration of poliovirus into packed
sand columns at room temperature ( Green
and Oliver, 19TU).
In solution, nitrate moves freely through the soil. Some denitrification
(reduction of nitrate to nitrogen gas) can occur where organic material and
an anaerobic environment occur together. Nitrogen in septic tank effluent
is about 80 percent ammonium and 20 percent organic nitrogen, but much of it
is converted biologically to nitrate as it moves through the aerated unsatur-
ated soil immediately below the clogging zone in the seepage field (Walker,
et al. 19T3b). This is illustrated in Figure l6 where concentrations of the
various forms of nitrogen are plotted against depth below a soil trench in a
sandy soil. If anaerobic conditions prevail in the subsoil, nitrification will
not occur and the nitrogen then remains in the form of ammonium. Ammonium is
readily adsorbed by soil materials of high clay content and hence migrates
much more slowly (Preul, 196U; Walker, et al. 19T3b).
In absorption fields where several feet of unsaturated flow in aerobic
soil occurs, nitrification followed by leaching of the nitrate into the
groundwater results. Some denitrification may occur in anaerobic "micro-
environments" within peds , but dilution is the primary mechanism available
to reduce nitrate concentrations to safe levels. In conditions of high ground-
water or very slowly permeable soils, anaerobic soil conditions may exist.
Under these conditions, nitrification is avoided and adsorption of ammonia onto
the clay and organic fraction of the soils occurs (Bouma, et al. 1972; Dudely
and Stephenson, 1973; Preul, 1966). As adsorption sites become exhausted,
ammonium travels. Most of the ammonium is subject to nitrification and leach-
ing if aerobic conditions are reestablished (Lance, 1972).
-------
10
20
MICROGRAMS PER GRAM SOIL
30 40 SO 100
100
300
10
20
30
40
50
60
70
80
IK)
170 •«
f30
AMMONIUM - N
NITRATF -N
CHLORIDE
ORGANIC -N
Figure 16. Concentrations of NH^-N, NOg-N, Organic N
and Cl in unsaturated soil below the clogged
zone in sand (Walker, et al. 19731) ).
Phosphorus is also of environmental concern. If allowed to reach surface
waters, it can accelerate eutrophication because it is an essential nutrient
of algae and aquatic weeds. However, phosphorus enrichment of groundwater
seldom occurs below septic tank systems because phosphorus is fixed in soil
by sorption reactions or as phosphate precipitates of calcium, aluminum or
iron.
When phosphorus is initially applied to the soil, it can be chemisorbed
on the soil mineral surfaces. As the concentration of phosphorus increases
in the soil solution, phosphate precipitates may form. The phosphate ion
forms relatively stable surface compounds or precipitates with compounds
containing iron or aluminum in neutral to acid soils or calcium in neutral
to alkaline soils.
The amount of phosphorus retained by a soil can be significant. In a
sandy loam soil, 100 mg/g to 300 mg/g of phosphorus was retained below a soil
absorption system (Walker, et al. 1973b). In sand column studies, 121 mg/g of
phosphorus was retained (Magdoff and Keeney, 1976). Based on this and data
collected by other investigators, it is estimated that the depth of phosphorus
penetration in sandy soils would be about 50 cm (20 in) per year while in
finer textured soils it may be as low as 10 cm (k in) per year (Sikora and
Corey, 1976). Therefore, groundwater contamination with phosphorus where clean
sands are found may become a problem, but only after a considerable length of
time.
The fate and significance of heavy metals and complex organic compounds in
the soil around absorption systems have not been determined. An insufficient
data base exists.
-------
Though the soil does not do a perfect jo~b of treating waste-water, proper
design and management of soil absorption systems allows the soil to absorb
the liquid and remove a very high percentage of the organisms and substances
potentially harmful to human health and the environment.
-56-
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SECTION 7
ON-SITE TREATMENT AND DISPOSAL ALTERNATIVES
A satisfactory wastewater treatment system discharges a vater of acceptable
quality which prevents the accumulation of harmful pollutants to dangerous
levels in the environment. The environment, of course, may be part of the sys-
tem, providing the final treatment necessary before the vater is of sufficient
quality for reuse. If the pollutant load received by the environment is too
great, the pollutants will not be broken down and recycled rapidly enough,
allowing the pollutants to accumulate. This leads to failure of the system.
The maximum permissible limits of pollutants that can be discharged vary
with the type of pollutant and the receiving environment. Therefore, to properly
design a wastewater treatment system, it is necessary to evaluate the physical
characteristics of the site where the partially treated wastewater is to be
discharged. Each site has its own characteristics that limit its potential as
a treatment medium. These characteristics will dictate the type and degree of
pretreatment that is required.
Proper evaluation of the receiving environment becomes particularly criti-
cal where on-site wastewater treatment systems are necessary. On-site systems
lack the advantage of central sewerage which collect and convey wastes to a
treatment plant located at a site which is selected for its suitability to
receive the pretreated wastes. Instead, they must be located near the point of
waste generation where local environmental conditions are often less than
i deal.
Traditionally, the septic tank-soil absorption system has been used to
provide on-site treatment and disposal of liquid systems. Soils are very
effective biological and physical filters which break down organic and other
chemical substances as well as remove pathogenic organisms and viruses.
Where soils are suitable, they should be utilized in the treatment system.
However, not all soils and the site characteristics with which they are
associated, are equally effective in providing absorption and purification
over a reasonable lifetime. If the soil and site characteristics preclude
soil absorption for on-site disposal, other alternatives must be sought
(see Figure 17).
An on-site wastewater treatment and disposal system must be designed
to produce an effluent of sufficient quality to be compatable with the
method of final disposal used. One or more unit processes would be placed
in series to provide the necessary treatment as shown in Figure 17. The
system selected may or may not be dependent upon soil for disposal. For a
detailed discussion of these systems, see Appendices A and B.
-57-
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SATISFACTORY-
SOIL AND SITE'
CHARACTERISTICS
\
IV
SITE
MODIFICATION
REGRADING
FILLING
DRAINING
UNSATISFACTORY
IN-HOUSE WASTE
MODIFICATION
CONSERVATION
SEGREGATION
REUSE
»- SOIL ABSORPTION
I CONVENTIONAL SOIL ABSORPTION
• MOUND
ET-ABSORPTION
EVAPORATION
EVAPOTRANSPIRATION
MECHANICAL EVAPORATERS
TREATMENT
BIOLOGICAL
PHYSICAL
CHEMICAL
SURFACE WATER
DISCHARGE
Figure IT. Alternative strategies- for on-site waste-water
treatment and disposal.
SYSTEMS DEPENDENT ON SOIL
The Conventional Septic Tank-Soil Absorption System
%
The most common method of on-site liquid waste disposal is the septic
tank-soil absorption system. The conventional septic tank system has two
components: a septic tank, used to provide partial treatment of the raw waste,
and the soil absorption field or pit where final treatment and disposal of the
liquid discharged from the septic tank takes place. Both are installed below
the ground surface.
The septic tank system has a bad reputation because failures are common.
Failure usually manifests itself by seepage of septic tank effluent to the
ground surface or by sewage back-ups in the house plumbing due to a clogged
soil absorption field. Since the system is near the home or establishment,
the seepage is readily accessible to humans and pets. The seepage may also
enter surface waterways, increasing the risk of exposure to potential health
hazards. A more serious type of failure, however, occurs when there is
insufficient or unsuitable soil below the absorption field to properly purify
the septic tank effluent before it reaches groundwater. Contamination of near-
by wells by bacteria, viruses and chemical pollutants can result. This
type of failure often goes unnoticed until illinesses or epidemics occur.
-58-
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Failure is not due to inherent shortcomings of the septic tank-soil
absorption system itself, but rather to misapplication and misuse. Where
soils are suitable, the septic tank-soil absorption field is an excellent
method of on-site disposal of wastewater. Therefore, site evaluation is a
critical step in its design.
Site Evaluation—
Site factors that influence the operation of on-site absorption systems
include the soil's hydraulic conductivity, the depth of soil over zones of
saturation or bedrock, the slope and topographic position, and the site's
management history. Of these, the soil's hydraulic conductivity and unsaturated
depth are most important to insure absorption of all the wastewater generated
and adequate treatment of the waste before the liquid reaches the groundwater.
Estimation of the Infiltrative and Percolative Capacity of Soil—Direct,
on-site measurement of hov the soil will respond to continuous wastewater
loading cannot be done practically. Instead, equilibrium flow rates through
clogged soils usually must be estimated from a short term empirical soil test.
The percolation test—In 1926, Henry Ryon developed a test to determine
the relationship between soil type and hydraulic loading of seepage systems
(Federick, 19^8). He studied both properly functioning and failing systems.
He dug a hole one foot square to the depth of the systems, soaked the hole
overnight to allow the soil to swell, refilled the hole the following day, and
recorded the time required for the water level to drop one inch ("percolation
rate"). To calibrate the test, Ryon inspected several failing or near-failing
systems and noted the loading of the system, the soil characteristics and the
percolation rate measured in nearby soil. Ryon plotted curves relating
loading rates versus the percolation rate from these data. It was later pro-
posed that these curves could be used to size new soil absorption systems.
Adoption of the procedure by the New York State Health Department led to its
wide acceptance, though slight changes have been made over the years. Today
it is used by most states to size on-site systems.
The use of the percolation test data for soil absorption system design
is based on the assumption that the ability of a soil to absorb sewage efflu-
ents over a prolonged period of time may be predicted from the soil's initial
ability to absorb clear water (McGauhey and Winneberger, 1963). From Ryon's
data comparing absorption rates of existing septic tank systems to the perco-
lation test, it is necessary to reduce the measured rate by an empirical
factor ranging from 20 to 2500 in order to size the absorption area (Bouma,
et al. 1972). However, tests run in the same soil can vary by several
orders of magnitude (Bouma, 1971; Healy and Laak, 1973; Winneberger, 197*0 •
Thus, the procedure is unreliable, and a more accurate test is desirable, or
at least, less reliance should be put on its results in system design.
The "crust test"—The soil below properly designed and operating absorp-
tion systems is unsaturated because of the clogging mat which develops at the
infiltrative surface. To properly size an absorption system, therefore,
the unsaturated hydraulic conductivity characteristics of the soil must be
known since the unsaturated conductivity is significantly less than the
-59-
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saturated conductivity. Since the standard percolation test does not provide
conductivity data of this type, the "crust test" was developed (Bouma, et al
1971, 1972; Bouma and Denning, 1972).
The crust test is performed in situ to avoid disturbing natural pores
and to maintain continuity with the underlying soil. A soil column is
carved from the soil horizon of interest and fitted with a ring infiltrometer
(an impermeable collar with a tight fitting lid) to control water addition
to the column. A tensiometer is installed in the column just below the infil-
trative surface to determine the degree of saturation in the soil by measuring
the soil moisture tension as water is applied (Figure 18). To create unsaturated
conditions in the soil column, a "crust" made of gypsum or gypsum and sand is
placed over the soil surface. When water is introduced through the infiltro-
meter, flow into the soil is restricted by the crust. This establishes a
constant steady-state flow which induces a nearly uniform moisture tension in
the soil beneath the crust. The measured soil moisture tension and the equil-
ibrium flow rate for a given crust determines one point on the hydraulic con-
ductivity curve. Additional tests run on the same column with crust of
different hydraulic resistances establish points that define a K-curve as shown
in Figure 9- This curve can be used for design if the range in soil moisture
tensions under the clogged zones of mature absorption systems in similar soils
is known.
MANOMETER
~-'i - a-\ TENSIOMETER
Figure 18. Schematic diagram of the crust test procedure.
-60-
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Though this procedure offers a direct measurement of K, it is time
consuming and requires a skilled operator. It is not a test which can be
run economically at each site. However, since the hydraulic conductivity of
a soil is dependent upon the pores in the system, the conductivity of a soil
at various sites in the soil map unit can Tbe defined within statistical limits
(Figure 19). Also, it has been found that curves of different soils in the
same textural groups are similar at moisture tensions greater than 10 mbar
(Figure 20). Therefore, by defining families of K-curves for groups of soils,
the hydraulic conductivity characteristics of a particular soil or site can
often be predicted without the need and expense of on-site testing.
In Wisconsin, four major hydraulic conductivity types have been suggested
based on the texture of the soil materials (Bouma, 1975). These textural
groupings include the sands; sandy loams and loams; silt loams and some silty
clay loams; and the clays and some silty clay loams. In other regions
similar groupings might be made, but they must be based on field data since
differences in soil mineralogy may affect these groupings. Typical hydraulic
conductivity curves were developed from field measurements for each of these
conductivity types (Figure 9).
> 10
PLANO SERIES
O.I 1.0 10.
SOIL MOISTURE TENSION
(cm water)
100
Figure 19. Hydraulic conductivity data for Piano series
Regression line is solid line, and dashed lines
indicate one standard deviation about
regression line.
-61-
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1000
100
u
O
o
(C.
o
I
10
0 I
GROUP B
GROUP A
I
O.I 10 10 100
SOIL MOISTURE TENSION (mBAR)
Figure 20. Hydraulic conductivity groups:
Group A: Ontonogon and Magnor series
(heavy loams)
Group B: Piano, Batavia and Merely series
(silty clay loams)
To make these curves useful in designing soil absorption fields for
septic tank systems, soil moisture tensions were measured under the clogging
zones of several operating fields (Bouma, 1915}• This information provided a
design point on the curve for proper field sizing. For example, the soil
moisture tension below a mature clogging mat in a silt loam soil is expected
to be between 20 and 3^ mbar. This corresponds to a K of from .67 to .92 cm/
day (Bouma, 1975). This same procedure could be used to select design points
for the other types of soil systems.
The application rates for various soil conductivity types defined in
Wisconsin and presented in Table 23, represent the best estimates available
to date. Because of the unstructured nature of the sands and sandy loams,
the rates are reasonably accurate. However, flow through finer textured soils
is more complex and there is more variability in the tensions measured under
operating fields (Bouma, 1975). In these soils the design rates must be used
with care particularly if expandable clays are present.
With no reasonably simple alternative to determine the equilibrium infil-
tration rate of soils under wastewater application, the percolation tests
continues to be favored. However, other information such as soil texture and
structure should be used to supplement and confirm the test.
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Estimation of the unsaturated depth of soil—To insure adequate purifica-
tion of the wastewater before it reaches groundwater, three feet of unsaturated
soil is necessary below the infiltrative surface. If saturated soils ever
occur within the three feet minimum, transmission of harmful pollutants to the
groundwater may result (Green and Cliver, 197**; McCoy and Ziebell, 1975;
Ziebell, 1975). To determine if saturated conditions do occur within the mini-
mum is often difficult, however, because water table levels fluctuate in
response to changing weather conditions. Typically, the water table is low
during the summer, while in the spring and fall, it rises. Ideally, the highest
groundwater level should be observed when it occurs, but this is not always
practical. Moreover, observations made in relatively dry years do not represent
those that occur in normal years. Thus, other methods must be used to determine
the high water elevation.
Soil mottling is sometimes an indicator of the presence of seasonally
high water levels. Mottles are spots of contrasting colors found in soils
subject to periodic saturation. The spots are usually bright yellow-orange-red
surrounded by a gray-brown matrix and described according to their color, fre-
quency, size and prominence (Soil Survey Staff, 1951). Well-drained soils are
usually brown in color due to the presence of finely divided insoluble iron and
manganese oxide particles distributed throughout the horizon. However, under
reducing conditions often produced by saturation over prolonged periods, the iron
and manganese is mobilized until reoxidized when the soil drains. Repetitive
wetting and drying cycles quickly produce local concentrations of these oxides
on pore surfaces forming red mottles (Vepraskas and Bouma, 1976). Soil from
which much of the iron and manganese has been completely reduced, loses its
brown color, and becomes grey by a process referred to as gleying. Therefore,
the upper limit of the mottled soil is often a good estimate of the high ground-
water level.
It is possible for soils to saturate and not develop mottles. In regions
where the water remains cold or bacterial activity is limited, mottle formation
is hindered. Also, soils with high pH may not develop pronounced mottling.
This is true of the red clay soils of Northern Wisconsin which saturate but do
not exhibit mottling.
Sizing of infiltrative surface—Proper design of the soil absorption field
requires that the rate of wastewater application to the infiltrative surface
not exceed the soil's equilibrium infiltration rate. The equilibrium infil-
tration rates have been determined for the various hydraulic conductivity soil
types in Wisconsin (Table 23), so it remains to estimate the total daily
volume of wastewater to be discharged to the field.
Waste flows from single homes, restaurants, motels, etc., are intermittent
and subject to wide fluctuations. Variation in the number of persons contribu-
ting to the flow and their activitieis have profound effects on the daily volume
of waste generated. Therefore, accurate estimates of waste flow volumes are
difficult. Estimates of per capita contributions from single homes are pre-
sented in Table U. More detailed estimates of household and commercial waste-
water flows are discussed in Appendix A.
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Because the flow must be contained in a limited area, soil absorption
fields must be designed for maximum rather than average daily flow unless
provisions are made for flow equalization. It is common practice to size the
infiltrative surface based on the maximum potential use of the building to be
served rather than its initially intended use. For example, to size a system
for a household in a soil with a percolation rate of 12 min/cm (30 min/in),
the Manual of Septic Tank Practice (USPHS 196?) recommends an absorption area
of 22.8 m
-------
while at the sidewall, gravity does not contribute to the potential gradient
since it operates vertically and the pressure potential diminishes to zero
at the liquid surface. In temperate climates, frequent rainfall, particularly
in the spring and fall, may reduce the matric potential at the sidewall to low
levels due to percolating precipitation. During such times, the horizontal
gradient could be significantly less than the vertical gradient with the effect
that the bottom surface would become the dominant infiltrative surface. For
this reason, Bouma (1975) recommends that in temperate climates, systems should
be sized on bottom area only. Healy and Laak (197^) do not suggest that a
system be designed on bottom area only, but they do recommend that in temperate
zones, systems be designed to function under gravity potential only because of
the problem during wet portions of the year. They also state that evapotrans-
piration during such times is too low to remove significant volumes of waste-
water because of the wet soil. The ability of the soil to transport the liquid
to the surface for evapotranspiration, of course, is directly related to the
matric potential or "wicking" action of the soil.
If the trenches were to remain ponded, deep narrow trenches could be con-
structed to increase the hydraulic gradient across the sidewall, as recommended
by McGauhey and Winneberger (1965). However, this would diminish the advantages
of shallow trenches which enhance the potential for evapotranspiration and avoid
construction in the deeper soil horizons where puddling and compaction are more
likely due to wet finer textured soil. It might be concluded that in humid
regions, systems should be designed on bottom area while maximizing the sidewall
by utilizing shallow trenches rather than beds. In more dry regions, with
rather permeable soils, the sidewall area could be maximized at the expense of
the bottom area.
Trench versus bed design—Though beds often are more attractive than
trenches because total land requirements, cost, and time of construction are
less, trenches are more desirable in terms of maintaining the infiltrative and
percolative capacity of the soil. This is particularly true in soils with
significant clay contents (>25 percent by weight). The principal advantages
of trenches over beds are that: l) more infiltrative surface is provided for
the same bottom area, and 2) less damage is likely to occur to bottom infil-
trative surface due to compaction, puddling and smearing during construction.
For identical bottom areas, trench designs of absorption fields can
provide more than 8 times the sidewall area. This can be of benefit in pre-
venting failure through clogging. In humid climates, there may be portions of
the year that the sidewall loses much of its effectiveness for absorption
which necessitates designing the system to function on bottom area only. How-
ever, it is recognized that the sidewall is beneficial and it is certainly
recommended to maximize it in any system (Bouma, 1975; McGauhey and Winneberger,
1975).
In addition, the seepage bed design can cause severe damage to the natural
soil structure during installation. This is a particular concern in clayey
soils. Rapid absorption of liquid by the soil depends on a suitable soil
structure being maintained (Bouma, 1975; Bouma,et al 1975a). When mechanical
forces are applied to moist or wet soil, the structure is partially or com-
pletely destroyed because clay particles in the soil are able to slip relative
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to one another. This movement, which, results in compaction, puddling or
smearing, closes the larger pores between soil aggregates and those made by
roots, or burrowing soil fauna.
To construct a seepage bed, it is common practice to first scrape off
the topsoil using a front end loader and then return with a backhoe for digging
to final grade in an attempt to leave a fresh soil surface. However, these
two operations may require several passes over the bed area by the construction
machinery often with heavy loads. When digging is complete, trucks may be
backed into the bed to unload aggregate which is spread over the bottom of the
bed with machinery. After the distribution piping is laid, additional gravel
is placed over the pipe and covered with soil. By the time the bed is com-
pleted, the soil structure may be destroyed.
This problem is further compounded when soil conditions are wet. A busy
contractor is unable to always schedule his work when the soil is dry,so
construction often proceeds when conditions are marginal at best. The trench
design reduces the severity of these problems because the construction
machinery is able to straddle the trench so that the future infiltrative surface
is never driven upon.
To make trench systems more favorable, design codes should encourage the
use of trenches. A reasonable approach would be to require more bottom area
for beds than trenches for the same size household. Two methods might be used:
l) give credit for sidewall area thereby reducing the bottom area required for
trenches, or 2) increase the bottom area now required for beds in proportion
to the amount of sidewall area lost by not using the trench design. Before
the former approach is recommended, however, more needs to be learned about
the relative contributions of the sidewall and bottom areas as infiltrative
surfaces.
Shallow versus deep absorption systems—Shallow soil absorption systems
offer several advantages over deep systems: l) the upper soil horizons are
usually more permeable than the deeper subsoil because of greater plant and
soil fauna activity and eluviated clay, 2) evapotranspiration is greater,
3) the upper soil dries quicker than the subsoil so construction can proceed
over longer periods of the year with less smearing, puddling and compaction,
and h) less excavation is necessary, reducing the cost. Some state codes
prohibit the construction of absorption systems deeper than 90 cm (36 in).
This restriction seems reasonable but only if more permeable soil horizons do
not exist at greater depths. In such instances, deep systems may be practical
where the groundwater tables does not preclude their use.
Freezing of shallow absorption systems is not a problem if kept in con-
tinuous operation even when frost penetration is quite deep. Weibel, et al.
(19^9) reviewed the literature and made contacts with health authorities and
plumbers in the northern states to determine if failures of shallow systems
were frequent due to freezing. They concluded that carefully constructed
shallow systems U5 cm to 60 cm (l8 in to 2k in) in depth would not freeze even
in areas where frost penetration reaches 1.5 m (5 ft), if the tile lines were
gravel packed and header pipes insulated where it is necessary for them to
pass under driveways or other areas usually cleared of snow.
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Distribution of Liquid Over the Infiltration Surface—
To insure that the objectives of absorption and treatment are met over a
long system lifetime, the method of wastewater application to the infiltrative
surface must be compatible with the local soil and site characteristics. That
is, suitable unsaturated conditions must exist for at least 90 cm (3 ft) below
the infiltrative surface at all times without excessive clogging occurring.
There are three basic methods of wastewater application for which a distribution
network can be designated: l) continuous ponding, 2) dosing and resting, and
3) uniform application without ponding.
Uniform application without ponding would seem to be the best loading
method for most soil and site conditions. In rapidly permeable soils, this
method is essential to insure adequate treatment during initial operation
when no clogging mat is present to prevent short-circuiting (Bouma, 1975).
In fine textured soils, however, it may not be possible to maintain a loading
regime or uniform application without ponding. A system designed to utilize
this method of application may revert to a continuously ponded regime due to
excessive clogging. Continuous ponding may be necessary in fine textured soils
to provide the necessary gradient across the clogging mat to absorb all the
wastewater. More research is needed to make this determination.
Dosing and resting loading regimes may be appropriate where absorption
is the principal concern. This is true only if dosing and resting, either on
a daily schedule or on a monthly or yearly schedule using alternating absorp-
tion systems, actually retard clogging. Again, more research is needed.
Limited laboratory and field data seem to be contradictory on this point. Dos-
ing and resting systems probably should not be used in highly permeable soils
with a high water table unless small, frequent doses are applied each day
(Bouma, 1975). Long periods of aeration would permit the clogging mat to de-
grade, thus allowing pollutants to penetrate to the ground water, as is the
case during initial operation of a system where no clogging mat is present.
Site limitations may be present which require loading methods that
spread the wastewater over a large area. Examples of these site limitations
are high ground water or shallow, impermeable bedrock or cemented pan where
groundwater mounding may occur to reduce the unsaturated depth of soil. Uniform
application without ponding would be best, although dosing and resting may be
suitable if the dosing volume necessary to pond the whole infiltrative surface
is not excessive. On steeply sloping sites, uniform application without
ponding would be the most appropriate to prevent seepage downslope. Very stony
or gravelly sites should be avoided unless suitable filtering material is brought
in.
Distribution network designs—Many different network designs have been
used in soil absorption systems all with the intent of uniformly ap'plying
liquid over the entire infiltrative surface. This rarely is achieved, but
it may not always be necessary. The designs include: large diameter
perforated pipe networks and pressure distribution networks. The choice of
one over the other depends upon the loading regime desired.
Large diameter perforated pipe networks — The conventional distribution
network for soil absorption fields consists of perforated 10-cm (
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diameter pipe through, which, the liquid flows by gravity. The pipe is laid
level or on an 0.17 to 0.33 percent slope. In multi-trench or bed systems,
the pipes are interconnected by a common solid wall header pipe, drop box
or distribution box.
The purpose of laying the pipe on a true, prescribed slope is to get
uniform distribution as the effluent trickles or flows in by gravity.
However, this is not the case, McGauhey and Winneberg (l96U) and Bouma, et al.
(19T2) observed nonuniform distribution. As it flows into the pipe, effluent
seems to exit out of a few holes either at the inlet area, middle or far end
of the trench. This causes localized overloading where small areas receive
a more or less continuous trickle of effluent. At first, adequate treatment
by the soil is not achieved because saturated flow conditions are created.
Soon, biological clogging occurs and reduces the infiltration rate below the
rate at which effluent is discharged. The effluent is forced to flow along the
bottom of the trench or bed until it reaches an unclogged area. This pheno-
menon, known as "creeping failure," continues until the total bottom area of
the system is clogged (Figure 21). Altering the orientation of the holes or
changing the slope of the pipe does not improve distribution significantly
(Converse, 197*0.
TRADITIONAL SUBSURFACE SEEPAGE BED
Gravity flow, continuous trickle of effluent
(till)
Equilibrium
I t t I I I I I t I I I I
Figure 21. Progressive clogging of the infiltrative
surfaces of subsurface absorption systems
(Bouma, et al. 1972).
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Periodic pumping of large volumes of effluent onto the field improves
distribution and provides an opportunity for the soil to drain "between
applications. Drainage exposes the infiltrative surface to air, reducing
clogging (Bouma, et al. 1975a; McGauhey and Winneberger, 19&3, 196*0. How-
ever, even with dosing, the effluent is not distributed over the entire in-
filtrative surface if the 10-cm (*J-in) pipe is used (Converse, 197*0-
Large diameter perforated pipe networks are best suited for continuously
ponded or dosing and resting loading regimes. For dosing applications, the
critical factor is to discharge by pump or siphon a sufficiently large volume
of liquid with each dose to submerge the entire infiltrative surface.
Pressure distribution networks—For uniform application of the wastewater
over the infiltrative surface, the distribution network must be designed
such that the volume of water passing out every hole within the network is
identical. This design permits much better control of application rates and
prevents local saturated conditions.
This is most easily done by putting the network under pressure and sizing
the pipe and hole diameters to balance the headlosses to each hole. Rules of
thumb used are: l) to assume at least 60 to 90 cm (2 to 3 ft) of head at the
terminal end of each lateral, 2) to assume that 65 to 85 percent of the total
headloss in the network occurs crossing the orifice, and 3) to assume that 10
to 15 percent of the total headloss occurs in delivering the liquid to each
hole. The remaining headlosses would occur through fittings (Otis, et al. 1977).
These systems combine uniform distribution with dosing, which enhance puri-
fication by promoting unsaturated flow and may reduce clogging.
Proper loading of permeable soils to prevent saturated flow is vital to
insure purification of the waste effluent. Pressure distribution systems
provide this loading control. Conventional gravity distribution is ineffective
(Converse, et al. 197*0- Pressure distribution systems also retard clogging.
Since the network is designed to apply no more liquid than an area of the
absorption bed can absorb each day, the soil remains well aerated. Absorption
fields in sand with pressure distribution have shown no evidence of clogging
after four years of operation (Converse, et al. 197*0, while fields in sand
with conventional distribution begin to clog after six months (Bouma, et al.
1972). The aerobic environment maintained by pressure systems promotes the
growth of microorganisms which destory clogging materials and appears to attract
larger fauna, such as worms, to consume nutrients accumulating at the infil-
trative surface. The worm's burrow help break up the clogging zone. Worm
activity explains why an absorption field in a silt loam underlain with glacial
till and dosed through a pressure distribution network at three time the USPHS
(1967) recommended rate has not clogged after three years of operation (Bouma,
et al. 1975a).
Pressure distribution networks may be the only alternative where rapidly
permeable soils are used for absorption in areas where groundwater contamin-
ation is possible. Further field demonstrations are necessary to determine
their value in other settings.
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Restoring the Infiltrative Capacity of a Clogged Absorption Field—
Soil absorption systems often fail after several years of satisfactory
service because the clogging zone eventually develops to a point where in-
sufficient amounts of effluent pass through it. Methods are being sought
to rejuvenate old fields so that failed systems need not be replaced.
Resting—One effective method of restoration is resting the system
(Bendixen, et al. 1950; Bouma, et al. 1972; McGauhey and Winneberger, 1963;
Weibel, et al 195*0. Resting allows the absorption field to gradually drain,
exposing the clogged infiltrative surface to air. After several months,
the clogging materials are broken up through physical and biochemical processes,
restoring the infiltrative capacity of the system. This requires a second
bed be available to allow continued use of the disposal system while the clogged
bed is resting. Two beds can be constructed when the disposal system is first
installed at the outset, with an alternating valve located after the septic
tank as shown in Figure 22. The two beds can then be use alternately by di-
verting the wastewater from one to another at an appropriate time interval.
If a system with only one bed has failed and a new one is constructed, pro-
visions should be made such that the old one is not abandoned, but can easily
be alternated with the new bed by use of an alternating valve arrangement.
Oxidizing agents—The infiltrative surface also can be rejuvenated by
the addition of oxidizing agents to the absorption field. The oxidizing agents
perform the same function as resting but the clogging zone is destroyed within
a day or two rather than several months. Such a method does not necessitate
taking the clogged bed out of service which eliminates the need for a second bed.
k\\\\\\\\\\\\\\N
\\\\\\\\\\\\\\Y
Figure 22. An alternating soil absorption field design.
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Laboratory and field tests indicate that chemical oxidation can restore the
infiltrative surface to near its original permeability (Harkin, 1975). The
oxidant preferred is hydrogen peroxide (Hg1^) because it is effective at the
natural pH of absorption fields, produces no noxious byproducts and is inexpen-
sive. Eight to 160 L (20-1*0 gai) of a 50 percent E^2 solution has been found
to be adequate for rejuvenating conventional soil absorption systems in sandy
soils serving single households. The use of this treatment needs further demon-
stration, particularly on systems in finer textured soils. Its usefulness is
limited, however, since it treats only the symptoms of failure and not the
causes. It may serve best as a preventive maintenance measure.
The Mound System
There are many areas where the conventional septic tank-soil absorption
field is not a suitable system of wastewater disposal. For example, sites
with slowly permeable soils, excessively permeable soils, or soils over shallow
bedrock or high groundwater do not provide the necessary absorption or puri-
fication of the septic tank effluent. However, these limitations often can be
overcome by constructing the soil absorption field above the natural soil in a
mound or medium sand fill (Figure 23).
There are several advantages to raising the soil absorption field. The
fill below the absorption trenches within the mound provides additional soil
material necessary to purify the wastewater before it reaches the groundwater
at sites with shallow or excessively permeable soils. At sites with slowly
permeable soils, the purified liquid is able to infiltrate the more permeable
natural topsoil over a large area and safely move away laterally until absorbed
by the less permeable subsoil. Also, the clogging mat that eventually develops
at the bottom of the gravel trench within the mound will not clog the sandy
fill to the degree it would in the natural soil. Finally, smearing and com-
paction of the wet subsoil is avoided since excavation in the natural soil is
not necessary.
The design of the mound is based upon the expected daily wastewater volume
it will receive and the natural soil characteristics (Converse, et al. l9T5a,
1975b, 1975c). It must be sized such that it can accept the daily wastewater
flow without surface seepage when perched water exists in the natural soil in
the spring and fall, as well as when the water table is lower during the summer
and winter. Size of the seepage trenches or bed and spacing of the seepage
trenches is important to avoid liquid rising into the fill below the seepage
area when the water table is high. In addition, the total effective basal
area of the mound must be sufficiently large to conduct the effluent into the
underlying soil.
A clean, medium sand is used as the fill material in construction of the
mound and gravel is used in the trenches. As in any seepage trench, a clogging
mat will develop at its interface. The ultimate infiltration rate through this
zone has been shown to be 5 cm/day (Bouma, 1975). Therefore, one consideration
must be to insure that sufficient trench area is available for the design flow.
As in conventional system sizing, bottom area is used for design, and sidewalls
constitute a safety factor.
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If more than one trench is constructed within the mound, another con-
sideration is the spacing between trenches. The area between trenches must
"be sufficient for the underlying natural soil to absorb all the liquid con-
tributed by the upslope trench. Infiltration rates into the natural soil are
based on the hydraulic conductivity characteristics of the least permeable
soil horizon 90 cm (3 ft) below the proposed site. The basal area required for
the mound is based on this as well.
To distribute the wastewater to each of the trenches, a pressure dis-
tribution network is used. This provides uniform application which is neces-
sary to prevent local overloading and eventual surface seepage due to short
circuiting through the mound fill.
Mound systems have been installed and monitored since 1972 and are per-
forming satisfactorily (Bouma, et al. 1973, 1975b). However, application of
proper siting, design, and construction techniques, described in detail by
Converse, et al. 1975a, 1975b, 1975c, are critical for satisfactory performance.
MARSH
HAY
SEPTIC TftNK PUMPING CHAMBER
f\\\\^l I'l'"1 ' "<' '
N^ /L.«"ii
Xs
( >' I' 111 I 111//\
2 \H PLASTIC
I IN PERFORATED
PLASTIC PIPE
PLAN VIEW
Figure 23. A plan view and cross-section of a mound
system for problem soils.
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Based on the success of the experimental mounds, their use for on-site disposal
are recommended for sites with: l) slowly permeable soils with percolation
rates at -60' cm (2k in) of 0.02 cm/min (120 min/in) or faster, 2) permeable
soils with percolation rates at 30 cm Cl ft) faster than Q.Ok cm/min (60 min/in)
over creviced or porous bedrock of 60 cm (2 ft), and 3) permeable soils with
percolation rates of 60 cm (2 ft) faster than 0.0k cm/min (60 min/in) with
water tables of 60 cm (2 ft). The three mound designs have been adopted in
several states.
SYSTEMS NOT DEPENDENT ON SOIL
At some sites, the soils may be totally inadequate as a treatment and
disposal medium. In such instances, on-site wastewater treatment systems not
dependent upon soil disposal, but which discharge the treated wastewater to
surface waters, to shallow soils overlying creviced bedrock or high water
tables, or to the atmosphere, are necessary.
Systems which must be designed to meet a certain water quality objective
may incorporate a variety of treatment processes discussed earlier, yet only
a select few will prove to be both economically and environmentally acceptable.
The selection process involves the evaluation of technical feasibility, cost
effectiveness and administrative feasibility. A systematic procedure is re-
quired to evaluate all physical constraints which may influence the selection
of treatment or disposal options. In all cases, an appropriate institutional
framework must be developed to insure appropriate construction, operation and
maintenance of the system.
Three experimental field systems which employed a selection of sequences
of processes were evaluated in this study over a two year period. The details
of the studies at field sites E, H and J appear in Appendix A. Figure 2k
depicts the flowsheets employed at these three field sites. A summary of the
performance of these three sites is presented in Table 2k. Data in Table 2k
has been extracted from Tables A-120, A-121, A-131, A-136 and A-139. It is
apparent from studying this summary tabulation that effluent qualities from
these three systems exceed current environmental quality standards for the
measured pollutants except for the nutrients, nitrogen and phosphorus, where
they are limited. Operation and maintenance characteristics of the systems
studied are delineated in Appendix A. Costs may be synthesized from data pre-
sented in Section 9.
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Site E
Septic Tank ->• Sand -*• Chlorination ->•
Tank Filter
Site H
Septic -> Aerobic -»• Sand •> Chlorination
Tank Unit Filter
Site J
Sand Filter -»• UV + Denitrification •+
Disinfection
Septic
Tank v
Aerobic + Sand Filter ^ UV "*" Denitrification
Unit Disinfection
Figure 2k. Flowsheets for three on-site
field systems
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SECTION 8
MANAGEMENT OF ON-SITE WASTEWATER DISPOSAL SYSTEMS
Improved techniques for design and installation of on-site wastewater
disposal systems can have a widespread effect on public health, "but it will
put additional burdens on the regulatory agencies to insure that proper
design and construction procedures are used. The lack of effective adminis-
tration and regulation by government agencies has been responsible for some
conventional system failures. The availability of alternate systems will in-
tensify this problem. Despite differences between the conventional and alter-
native systems, their administration and regulation should be similar. Present
regulatory schemes used by states and counties can be adapted to provide
better regulation of all types of systems. A more detailed discussion of this
topic is presented in Appendix D.
REGULATORY AUTHORITY OPTIONS
Programs for regulating on-site disposal systems varies widely from state
to state and among local authorities (usually local units of government or
health authorities). The programs used vary from no state or local regulation
whatsoever to almost total state regulation of all on-site systems. Some pro-
grams share responsibility between the local and state authorities for setting
standards, inspection, permit issuance, and enforcement.
The various regulatory prgorams can be categorized into four general
types (Stewart, 197^a). First, many states require a state permit for on-site
systems and a site inspection by a state agent (Patterson, et al., 19T1). This
is an effective approach because the pressure often put upon enforcement
officials, which can weaken a regulatory program, is usually not as effective at
the state level as at the local level.
Second, a few states have no regulation program at either the state or
local level (Patterson, et al., 1971). Some of these states supply the public
with information on system design, but only for public education purposes.
Some of these states will take regulatory action against on-site systems only
if a water pollution or health violation is perceived.
Third, some states defer all permit and inspection responsibilities to
county or town government or health authorities (Patterson, et al., 1971).
In some of these states, a state code of minimum standards and specifications
for on-site systems have been adopted requiring local codes and standards to
be at least as stringent as the state codes.
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Fourth, some states divide responsibilities with the local authorities
regulating single family disposal systems and the state regulating all sub-
divisions and commercial installations. For example, the State of Wisconsin
issues construction permits and inspects all systems serving public buildings
such as theaters, assembly halls, schools, apartment buildings, hotels, prisons,
factories, mobile homes, camps and parks while county authorities regulate all
one and two family systems.
Standards and specifications for installation of on-site systems used by
the 50 states also vary. Many states base their standards on the U.S. Public
Health Service's Manual of Septic Tank Practice (1967)• However, other states
and localities have developed standards of their own.
REGULATION AND CONTROL
A regulatory program should control the installation, operation and ulti-
mate failure phases of all on-site wastewater disposal systems (Stewart, 197^-a,
197^b). Within each phase, one or more problems can arise where regulation
can help to prevent public health hazards from occurring.
System Phases Requiring Regulation
Installation of on-site systems includes site selection, design and con-
struction. The type of disposal system installed and design criteria used
are determined by the site. The regulatory program must insure that the
proper system is chosen and the installation criteria followed.
Operation of the disposal system includes regular and proper maintenance.
This must be assured to prevent premature failures. For a conventional septic
tank system, this involves inspecting the tank and pumping it when necessary.
With alternative systems, operation and maintenance requirements may be more
extensive. The regulatory program must insure that appropriate operation and
maintenance requirements are met.
Failure of the system may ultimately occur. The regulatory agency should
take action to detect failures and to obtain their correction. This involves
an assessment of the failure and analysis of alternative corrective measures
permitted by the regulations, followed by what can be construed as an install-
ation phase of activity.
Inspections and Permits
Most agencies employ on-site inspections and permit or license issuance
to regulate disposal systems. Inspections are generally made during installa-
tion. Many regulatory programs only require a "pre-cover up" inspection of the
completed system. To be more effective, several inspections should be made
including one of the proposed site prior to approving the installation. Like
inspections, permits generally are associated only with the installation phase.
Good regulatory programs usually require at least two permits for each system.
The first typically authorizes construction of the proposed system on a desig-
nated site, and is issued after application by the homeowner following in-
spection of the site or examination of soils and site data. The second permit,
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referred to as a use/occupancy permit, is typically issued after construction
and final inspection of the system is made which authorizes the owner to use
the system. Possible uses of inspections, permits and other functions to
regulate installation of on-site systems are shown in Table 25.
Inspections and permits also can be used to regulate operation and correct
failures. For example, a revocable permit to use the system may be used to
insure that septic tanks are pumped. Mandatory regular inspections could be a
pre-requisite for the re-issuance of this "operational" (maintenance) permit.
Other examples of inspections and permits use are discussed in the following
section.
SUGGESTED IMPROVEMENTS FOR REGULATORY PROGRAMS
Suggested improvements for regulation of on-site systems have been made
based on a review of regulatory schemes used by many states (Stewart, 197^a,
19T^b). These suggestions are not applicable to every state nor are they
possible for all states to adopt because of constitutional limitations and
requirements. Some of the methods summarized below, however, could be employed
by many agencies to improve their regulatory programs.
Installation
1. State permit program. A state agency would receive applications
for all on-site systems, make inspections and issue permits for
installation and/or use of disposal systems to reduce local
political pressure on authorities to approve systems on unsuited
sites.
2. State plan review/state standards. Alternatively, a state agency
would review all or a representative sample of all on-site
permits issued by local agencies and establish guidelines for
local authorities to develop regulatory programs and minimum
specifications.
3. Uniform citation and complaint. State and localities should develop
methods of issuing citations for sanitary ordinance or code vio-
lations to expedite enforcement and permits.
U. Small claims courts. The less formal procedures of small claims
courts should be used to accelerate the imposition of fines and
forfeitures for violations of on-site system standards.
5. Civil service status. Regulatory officials should be given job
security to protect them from pressures exerted by parties with
vested interests.
Operation
1. Septic tank maintenance permit. Permits could be issued every 1
to 3 years upon receipt by the regulatory agency of proof that the
septic tank has been inspected and/or pumped.
-78-
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2. Conditional sanitary permit. A permit to install and use a system
could be issued which would become void upon proof by the regula-
tory authority that proper maintenance had not been performed.
3. Location and filing requirement. This would require the filing of
an "as-built" plan showing the size and location of the disposal
system to simplify servicing.
Failure
1. Sanitary surveys. Periodic inspections could be made to locate failing
systems within the jurisdiction of the regulatory authority.
2. Violation as an encumbrance. Notice of a violation could be filed
by the regulatory authority with the register of deeds to alert
potential buyers of the system.
3. Pre-sale inspection. The regulatory authority could inspect the
systems whenever the property is sold.
U. Abatement costs. Regulatory authorities should have the author-
ity to enter upon private land to abate a failing system and charge
the owner for the work.
MANAGEMENT BY GOVERNMENTAL OR QUASI-GOVERNMENTAL UNITS
Although state and local authorities may regulate the installation and
possibly the use of individual on-site systems, owners usually are responsible
for the operation, maintenance and repair or on-site disposal systems. An
alternative to this is the use of governmental or quasi-governmental units to
install, operate, maintain, repair, and perhaps even own on-site systems
(Otis and Stewart, 1976; Stewart, 1975b). Appropriate governmental units might
include special purpose districts such as sanitary districts and drainage
districts or might involve a special function of existing governmental units
such as towns or counties.
Regardless of the type or size of the governmental unit, advantages of
this would be: l) control over system siting and design, 2) strict supervision
of construction, 3) proper inspection and maintenance, and U) immediate replace-
ment of failing systems (probably paid for out of a replacement fund). How-
ever, there might be economies of scale in larger jurisdiction units which
might make county level units more preferable.
The governmental or quasi-governmental unit should have the following
powers (Otis and Stewart, 1976; Stewart, 1975b). Some additional optional
powers also have been included (89).
1. Authority to plan, design, construct, operate and maintain all
types of on-site systems, and the optional authority to own, pur-
chase, lease and rent both real and personal property.
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2. Authority to accept and utilize state and federal grants, and
further sufficient authority to meet eligibility requirements
imposed upon grant applicants.
3. Authority to contract, undertake debt obligations and to sue and
to be sued.
k. Authority to raise revenue by fixing and collecting user charges
for sewer services and as an optional revenue raising power,
authority to determine and assess the benefit to any property
served and collect that assessment from each property owner and/or
have the power to levy a tax upon the landowners served.
5. Authority to plan and control how and when wastewater facilities
will be provided to those within its jurisdiction, and
6. Authority to adopt needed rules and regulations governing the con-
trol and use of on-site systems within its jurisdiction.
Entities other than governmental or quasi-governmental units with powers
to adequately manage on-site systems have been identified (Commission on
Rural Water, 1971*; Otis and Stewart, 1976; Stewart, 1975"b): l) incorporated
cities and villages (local units of general government which have home rule
powers), 2) counties and townships (local units of general government),
3) special purpose districts (quasi-governmental units), h) private non-profit
corporations, 5) rural electric cooperatives (cooperatives established to work
with U.S.D.I.'s Rural Electrification Administration, 6) private businesses,
and 7) other governmental agencies.
The use of governmental or quasi-governmental units to own and operate
individual on-site disposal systems is a relatively new concept, but some
have been successfully established in California, West Virginia, Florida and
Wisconsin (Otis and Stewart, 1976). Experience seems to indicate that the
concept is sound.
LAND USE IMPLICATIONS OF IMPROVED ON-SITE DISPOSAL TECHNOLOGY
The introduction of new on-site waste disposal technology raises questions
about land use and land development. Regional planning commissions should under-
stand the new technology and realize its possible impact on land use. Home and
commercial development, as well as land values, may be increased, especially
in areas where site conditions were hitherto unsuitable for on-site disposal
systems. Planning commissions will be forced to redefine criteria for land
use decisions.
Potential Areas of Impact on Land Use
In many parts of this country, planners have relied on the unsuitability
of lands for conventional systems as a tool in determining land use. Central
public sewerage is often too expensive for sparsely populated areas. Thus,
development is effectively prevented in rural areas unsuited for septic tank
systems by what is commonly referred to as de facto zoning. The availability
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of alternate systems for on-site waste disposal or more cost effective
methods of public sewerage could have impact on land use, especially de facto
zoning.
Alternate Systems - Case Studies of Potential Impact
Two case studies (Amato and Goehring, 197^; Water Resources Management
Workshop, 1973) suggest that alternate on-site disposal systems could have
considerable impact, especially in these areas which currently rely on de facto
zoning. Any area meeting the reduced site and soil requirements of alternative
systems will "be open to development unless curtailed by other mechanisms of
land use control. The development of resource data to advise officials of
appropriate governmental units should be a top priority assignment of planning
commission (Amato and Goehring, 197^ )•
Soil Surveys to Predict Land Use Implications
Soil surveys have been used, in part, to evaluate potential sites for
wastewater disposal with conventional septic tank systems. Soil surveys now
should be also used to predict the potential of sites for alternate methods of
waste disposal (Beatty and Bouma, 1973). Such information is vitally needed
in jurisdictions which rely on de facto zoning instead of more valid methods
of land use controls. Land use controls should be based on the desires of the
community and not fortuitous circumstance that certain lands are not suited
for conventional septic systems.
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SECTION 9
ALTERNATIVE SELECTION
THE SELECTION PROCESS
The choices available for the individual home waste-water disposal are
numerous, yet only a selected few will prove to be both economically and
environmentally acceptable. The selection process involves the evaluation
of technical feasibility, cost effectiveness and administrative feasibility.
All three are extremely important to the successful execution of the project.
Table 26 is a listing of some of the on-site wastewater disposal options
available. It is first necessary to evaluate the design constraints for the
site, including soils, topography, geological characteristics, climate and
water quality requirements. Once these physical constraints have been de-
lineated, an orderly selection of options may be undertaken. With each of
the feasible alternatives, an appropriate institutional framework must be
developed to insure appropriate construction, operation and maintenance of
the system. Finally, the capital and operation and maintenance costs of each
feasible alternative, including cost of the administrative framework must be
determined. This is necessary to select the most cost effective alternative
from those evaluated.
Examples of some potential system flowsheets are depicted in Table 27.
It should be emphasized that although technical feasibility of many of these
systems is proven, extensive field testing to determine process reliability
and effectiveness of institutional controls still needs to be accomplished.
COSTS OF TREATMENT AND DISPOSAL SYSTEMS
With the exception of standard septic tank-soil absorption systems, the
cost of alternative on-site treatment and disposal systems are not well docu-
mented, owing to the lack of a large enough data base. Estimates of unit
cost ranges are presented in Table 28, and are based primarily upon Wisconsin
experiences. It should be recognized that these costs are merely estimates
based on relatively sparse experience and individual systems should be evalu-
ated on a site by site basis. In all instances, in-house devices may sub-
stantially decrease overall costs for treatment and disposal.
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TABLE 26. ON-SITE WASTEWATER TREATMENT AND
DISPOSAL COMPONENTS
In-House
Water Conservation
Flow Control
Reuse and Recycle
Waste Segregation
Non-Water Carriage Toilets
Chemical
Biological
Recycle
Incinerator
Very-Low-Flow Toilets
Household Product Selection
Household Appliance Selection
Anaerobic Processes
Septic Tanks
Fixed Media Filters
Sand
Synthetic Media
Aero~bic Processes
Suspended Growth
Activated Sludge
Lagoons
Fixed Media
Soil Mantle
Granular Filters
Coarse Media
Rotating Biological Contactors
Trickling Filters
Emergent Vegetation
Physical Chemical Processes
Ion Exchange
Chemical Precipitation
Disinfection
Halogens
Ultraviolet
Ozone
Adsorption
Land Application for Disposal
Soil Absorption
Mounds
Irrigation
Lagoons (Absorption)
Evapotranspiration
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P£FE FENCES
Adriano, D. C., L. T. Novak, A. E. Erickson, A. R. Wolcott, and B. G.
Ellis. 1975. Effect of Long Term Land Disposal by Spray Irrigation
of Food Processing Wastes on Some Chemical Properties of the Soil and
Subsurface Water. J. Env. Qual. 4:242-248.
Alexander, M. 1961. Introduction to Soil Microbiology. John Wiley £
Sons, Inc., New York.
Allison, L. E. 1947. Effect of Microorganisms on Permeability of Soil
Under Prolonged Submergence. Soil Sci. 63:439-450.
Allison, F. E. 1965. Organic Carbon. Iia Methods of Soil Analysis,
Part 2. C. A. Black, ed. Amer. SocT Agron., Madison, Wisconsin.
Amato, P. W. and H. D. Goehring. 1974. Land Use and Policy Implications
in a Three County Wisconsin Area. Small Scale Waste Management
Project, University of Wisconsin, Madison.
American Society of Civil Engineers. 1937. Filtering Materials for
Sewage Treatment Plants. Manual of Engineering Practice No. 13,
ASCE, 17.
American Society of Civil Engineers. 1970. National Specialty Conference
on Disinfection, ASCE, New York.
Anderson, J. L. and J. Bouma. 1973. Relationships Between Saturated
Hydraulic Conductivity and Morphometric Data of an Argillic Horizon.
Soil Sci. Soc. Amer. Proc. 37:408-413.
Anderson, J. L. and J. Bouma. 1977a. Water Movement Through Pedal Soils:
I. Saturated Flow. Soil Sci. Soc. Amer. J. 41(2):413-418.
Anderson, J. L, and J. Bouma. 1977b. Water Movement Through Pedal Soils:
II. Unsaturated Flow. Soil Sci. Soc. Amer. J. 41(2):419-423.
Anonymous, 1961. Water Demands of Decentralized Community Facilities.
Public Works, 92(9):102.
Anticimexbolagen. 1971. Stockholm, Sweden.
Applebaum, S. B. 1968. Demineralization by Ion Exchange. Academic Press,
New York.
-87-
-------
Autotrol Corporation. 1972. Bio-Systems Division, Milwaukee, Wisconsin,
Avnimelech, Y. and Z. Nevo, 1964. Biological Clogging of Sands. Soil
Sci. 98:222-226.
Bailey, J. R., R. J. Benoit, J. L. Dodson and J. M. Robb. 1969. A Study
of Flow Reduction and Treatment of Wastewater from Households.
Federal Water Quality Administration Publication Number 11050 FKE,
NTIS Order No. PB 197-599.
Baker, F. G. 1976a. Variability of Hydraulic Conductivity Characteristics
in Selected Structured and Nonstructured Soils. Small Scale Waste
Management Project, University of Wisconsin, Madison.
Baker, F. G. 1976b. A Model for Planning and Location of On-site Waste
Disposal Systems. Small Scale Waste Management Project, University
of Wisconsin, Madison.
Baker, F. G. 1976c. Reduced Infiltration in Dosed Soil Columns. Small
Scale Waste Management Project, University of Wisconsin, Madison.
Baker, F. G. 1976d. Factors Influencing the Crust Test for in situ
Measurement of Hydraulic Conductivity. Soil Sci. Soc. Aroer.
Journ. 41:1029-1032.
Baker, F. G. and J. Bouma. 1976a. Measurement of Soil Hydraulic Conduc-
tivity and Site Selection for Liquid Waste Disposal. In_ Proceedings
of Second National Conference on Individual On-site Wastewater Systems.
National Sanitation Foundation, Ann Arbor.
Baker, F. G. and J. Bouma. 1976b. Variability of Hydraulic Conductivity
in Two Subsurface Horizons of Two Silt Loam Soils. Soil Sci. Soc.
Amer. Proc. 40:219-222.
Battelle Northwest. 1969. Ammonia Removal From Agricultural Runoff and
Secondary Effluents by Selected Ion Exchange. R. A. Taft Water
Research Center Report No. TWRC-5, U.S. Department of Interior.
Battelle Northwest. 1971. Wastewater Ammonia Removal by Ion Exchange.
Water Pollution Control Research, Series No. 17010 ECZ 02/71, USEPA.
Baumann, R. E. and H. E. Babbitt. 1954. Improving Septic Tank Efficiency
With a Gas Deflection Baffle. Water and Sewage Works, 101(3):132.
Baumer, 0. W., F. F. Peterson, and R. B. Grossman. 1976. A Permeameter for
_in_ situ Soil Profile Permeability or Individual Horizon Hydraulic
Conductivity Characterization. Submitted to Soil Soc. Amer. Jour.
-------
Bayer, L. D., W. H, Gardner and W. R. Gardner. 1972. Soil Physics.
John Wiley and Sons, Inc. New York, New York.
Beale, C. L. and G. V. Fuguitt. 1975. Population Trends in Non-Metropolitan
Cities and Villages in Subregions of the United States. CDE Working
Paper 75-30, Center for Demography and Ecology, University of Wisconsin,
Madison, Wisconsin.
Seek, J. and F. A. M. deHaan. 1974. Phosphate Removal by Soil in Relation
to Waste Disposal. Proc. International Conference on Land for Waste
Management. Ottawa, Canada (1973), pp. 77-86.
Bendixen, T. W., M. Berk, J. P. Sheehy and S. R. Weibel. 1950. Studies on
Household Sewage Disposal Systems. Part II. Federal Security Agency,
Public Health Service, Environmental Health Center, Cincinnati, Ohio.
Bendixen, T. W., R. E. Thomas and J. B. Coulter. 1962. Study to Develop
Practical Design Criteria for Seepage Pits as a Method of Disposal of
Septic Tank Effluent. Report to FHA, Robert A. Taft Sanitary Engineer-
ing Center, USPHS, Cincinnati, Ohio.
Bennett, E. R. and K. D. Linstedt. 1975. Individual Home Wastewater
Characterization and Treatment. Completion Report Series No. 66,
Environmental Resources Center, Colorado State University, Fort
Collins, Colorado.
Bent, M. G. 1975. Phosphate Removal From Septic Tank Effluent by
Limestone. M.S. Thesis, Department of Soil Science, University of
Wisconsin, Madison, Wisconsin.
Sergey's Manual of Determinative Bacteriology. Eds. R. E. Buchanan and
N. E. Gibbons. 1974. 8th Ed. Williams and Wilkens, Baltimore.
Bernhart, A. P. 1967. Wastewater From Homes, University of Toronto,
Toronto, Ontario.
Bhaumik, H. D. and F. E. Clark. 1947. Soil Moisture Tension and Microbial
Activity. Soil Sci. Soc. Amer. Proc. 11:234-238.
Bishop, W. J. 1975. Field Experience in Water Saving Programs of the
Washington Suburban Sanitary Commission. Proceedings of the Conference
on Water Conservation and Sewage Flow Reduction with Water-Saving
Devices, Pennsylvania State University, University Park, Pennsylvania.
Bitton, G. 1975. Adsorption of Viruses Onto Surfaces in Soil and Water.
Water Research 9:473-484.
-89-
-------
Black, C. A. 1970, Chapter 6: Behavior of Soil and Fertilizer Phosphorus
in Relation to Water Pollution. In_ Willrich, T. L. and G. E. Smith
(eds.), Agricultural Practices and Water Quality.
Boersma, L. 1965. Field Measurement of Hydraulic Conductivity Above a
Water Table. In Methods of Soil Analysis, Part 1, C. A. Black ed.,
Amer. Soc. Agron., Madison, Wisconsin, pp. 234-252.
Boul, S. W., F. D. Hole and R. J. McCracken. 1973. Soil Genesis and
Classification. Iowa State University Press, Ames, Iowa. 360 pp.
Bouma, J. 1971. Evaluation of the Field Percolation Test and An Alternative
Procedure to Test Soil Potential for Disposal of Septic Tank Effluent.
Soil Sci. Soc. Amer. Proc. 35:871-875.
Bouma, J. 1973. Use of Physical Methods to Expand Soil Survey Interpreta-
tions of Soil Drainage Conditions. Soil Sci. Soc. Amer. Proc. 37:413-
421.
Bouma, J. 1974. New Concepts in Soil Survey Interpretations for On-site
Disposal of Septic Tank Effluent. Soil Sci. Soc. Amer. Proc.,
Vol. 38:941-946.
Bouma, J. 1975. Unsaturated Flow During Soil Treatment of Septic Tank
Effluent. J. Environ. Eng. Div., ASCE, EE6, Proc. Paper 11783
101:967-983.
Bouma, J. 1977. Subsurface Applications of Sewage Effluents. In_ Land Use
Planning. M. T. Beatty and G. W. Peterson (eds). Amer. Soc. Agron.,
Madison, Wisconsin (in press).
Bouma, J. and J. L. Anderson. 1973. Relationships Between Soil Structure
Characteristics and Hydraulic Conductivity. In: R. R. Bruce, ed.
The Soil Moisture Regime, ASA Special Publication No. 5, Madison,
Wisconsin, pp. 75-105.
Bouma, J. and J. L. Denning. 1972. Field Measurement of Unsaturated
Hydraulic Conductivity by Infiltration Through Gypsum Crusts.
Soil Sci. Soc. Amer. Proc. 36:846-847.
Bouma, J., F. G. Baker, and P. L. M. Veneman. 1974a. Measurement of Water
Movement in Soil Pedons Above the Watertable. Information Circular
No. 27, Wis. Geol. Nat. Hist. Surv. 114 p.
Bouma, J., J. C. Converse, J. Carlson and F. G. Baker. 1975a. Soil
Absorption of Septic Tank Effluent in Moderately Permeable Fine Silty
Soils. Transactions, ASAE 18:1094-1099.
-90-
-------
Bouma, J., J. C. Converse and F, R. Magdoff. 1974b. Dosing and Resting
to Improve Soil Absorption Beds. Trans. ASAE 17:295-298.
Bourna, J., J. C, Converse and F. R. Magdoff. 1974c. A Mound System for
Disposal of Septic Tank Effluent in Shallow Soils Over Creviced
Bedrock. _In_ Proceedings of the International Conference on Land for
Waste Management, Agricultural Institute of Canada, Ottawa, Canada,
pp. 367-378.
Bouma, J., J. C. Converse, R. J. Otis, W. G. Walker, and W. A. Ziebell.
1975b. A Mound System for On-site Disposal of Septic Tank Effluent
in Slowly Permeable Soils With Seasonally Perched Water Tables.
J. Environ. Qual. 4:382-388.
Bouma, J., D. I. Hillel, F. D. Hole and C. R. Amerman. 1971. Field
Measurement of Unsaturated Hydraulic Conductivity by Infiltration
Through Artificial Crusts. Soil Sci. Soc. Amer. Proc. 35:362-369.
Bouma, J., W. A. Ziebell, W. G. Walker, P. G. Olcott, E. McCoy and
F. D. Hole. 1972. Soil Absorption of Septic Tank Effluent: A Field
Study of Some Major Soils in Wisconsin. Information Circular No. 20,
Univ. of Wis. Ext. and Geol. Nat. Hist. Surv., Madison, Wisconsin. 235 p.
Bouwer, H. 1962. Field Determination of Hydraulic Conductivity Above A
Water Table With A Double Tube Method. Soil Sci. Soc. Amer. Proc.
26:330-335.
Bouwer, H. 1964a. Measuring Horizontal and Vertical Hydraulic Conductivity
of Soil With the Double-Tube Method. Soil Sci. Soc. Amer. Proc.
38:19-23.
Bouwer, H. 1964b. Simplified Procedure for Calculation of Hydraulic
Conductivity With the Double-Tube Method. Soil Sci. Soc. Amer. Proc.
38:133-134.
Bouwer, H. and H. C. Rice. 1964. Simplified Procedure for Calculation of
Hydraulic Conductivity With the Double-Tube Method. Soil Sci. Soc.
Amer. Proc. 28:133-134.
Boyce, E. 1927. Intermittent Sand Filters for Sewage. Municipal and
County Engineer 72:177.
Brady, N. C. 1974. The Nature and Properties of Soils, MacMillan
Publishing Co., Inc., New York.
Bremner, J. M. 1965a. Total Nitrogen. In; Methods of Soil Analysis,
Part 2, C. A. Black, ed. Amer. Soc. of Agron., Madison, Wisconsin.
pp. 1171-1178.
-91-
-------
Bremner, J. M. 1965b. Inorganic Nitrogen. In: Methods of Soil Analysis,
Part 2, C. A. Black, ed., Aroer. Soc. of Agron., Madison, Wisconsin.
pp. 1179-1237.
Bremner, J. M. and D. R. Keeney. 1965. Steam Distillation Methods for
Determination of Ammonium, Nitrate and Nitrite. Anal. Chim. Acta 32:
485-495.
Broadbent, F. E. and F. Clark. 1965. Denitrification. p. 344-359.
In; W. V. Bartholomew and F. E. Clark (ed.) Soil Nitrogen. Amer.
Soc. Agron., Madison, Wisconsin.
Brown, M. R. W., ed. 1975. Resistance of Pseudomonas Aeruginosa.
John Wiley, Ltd. London.
Brown, R. L. 1975. The Occurrence and Removal of Nitrogen in Subsurface
Agricultural Drainage From the San Joaquin Valley, California.
Water Res. 8:529-546.
Budde, P. E., P. Nehm, and W. C. Boyle. 1977. Alternative to Wastewater
Disinfection. JWPCF, 49:2144-2156.
Burns, G. R. 1967. Oxidation of Sulphur in Soils. Tech. Bull. No. 13.
The Sulphur Institute, Washington, D.C.
Bybordi, M. 1968. Moisture Profiles in Layered Porous Materials During
Steady State Infiltration. Soil Sci. 105:379-383.
Calcott, P. H., S. K. Lee, and R. A. MacLeod. 1975. The Effect of Cooling
and Warming Rates on the Survival of a Variety of Bacteria. Can. J.
Microbiol. 22:106-109.
Cannell, G. H. and C. W. Asbell. 1974. The Effects of Soil-Profile Varia-
tions and Related Factors on Neutron-Moderation Measurements. Soil
Sci. 117:124-127.
Calcott, P. H., S. K. Lee, and R. A. MacLeod. 1975. The Effect of Cooling
and Warming Rates on the Survival of a Variety of Bacteria. Can. J.
Microbiol. 22:106-109.
Carlson, G. F. Jr., F. E. Woodard, D. F. Wentworth, and 0. J. Sproul.
1968. Virus Movement in Groundwater. J. Water Pollut. Control Fed.
40:257-271.
Chan, H. T. 1976. Effect of Hole Size on Percolation Rate in a Field
Percolation Test. Publ. No. S60, Pollution Control Branch, Ministries
of Environment, Toronto.
-92-
-------
Chang, S. L. 1958. The Use of Active Iodine as a Water Disinfectant.
J. Amer. Pharm. Assn. Scientific Edition, 47:417.
Chen, R. L., D. R. Keeney, J. G. Konrad, A. J. Holding, and D. A. Graetz.
1972. Gas Production in Sediments of Lake Mendota, Wisconsin.
J, Environ. Qual. 1:155-158,
Chen, Yi-Shon R., J. N. Butter and W. Stumm. 1973. Adsorption of
Phosphate on Alumina and Kaolinite from Dilute Aqueous Solutions.
J. Colloid and Interface Sci. 43:421-436.
Cheng, H. H. and J. M. Bremner. 1965. Gaseous Forms of Nitrogen.
p. 1287-1323. In; C. A. Black et al. (ed.) Methods of Soil Analysis,
Part 2. Amer. Soc. Agron., Madison, Wisconsin.
Chick, H. 1908. The Laws of Disinfection. Journal of Hygiene 8:92.
Childs, E. C. 1969. An Introduction to the Physical Basis of Soil Water
Phenomena. John Wiley, New York, New York, 493 p.
Childs, K. E. 1973. The Failure of Septic-Tank Systems. Open file report.
Geological Survey Division, Michigan Department of Natural Resources,
Lansing, Michigan, 141 pp.
Cliver, D. 0. 1965. Factors in the Membrane Filtration of Enteroviruses.
Appl. Microbiol. 13:417-425.
Cliver, D. 0. 1967. Enterovirus Detection by Membrane Chromatography,
p. 139-141. In: G. Berg (ed.), Transmission of Viruses by the
Water Route. Interscience, New York.
Cliver, D. 0. 1968. Virus Interactions with Membrane Filters. Biotech.
Bioeng. 10:877-889.
Cliver, D. 0., and R. M. Herrmann. 1969. Economical Tissue Culture
Technics. Health Lab. Sci. 6:5-17.
Cliver, D. 0. and J. E. Herrmann. 1972. Proteolytic and Micro-bial
Inactivation of Enteroviruses. Water Research 6:797-805.
Chowdhry, N. A. 1972 and 1973. Interim Report on "Underdrain Filter
Systems - Whitby Experiment Station," Parts 1 and 2, Private
Wastewater Branch, Ministry of the Environment, Ontario, Canada.
Clark, B. 1968. Houseboat Waste Characteristics and Treatment. Federal
Water Pollution Control Administration, Pacific Northwest Laboratory.
Clark, B. D. 1969. Basic Waste Characteristics at Winter Recreation
Areas, National Technical Information Service, PB 208 437.
-93-
-------
Clark, H. W. and S. Gage. 1909. A Review of Twenty-One Years Experiments
Upon the Purification of Sewage at the Lawrence Experiment Station.
Fortieth Annual Report of State Board of Health of Massachusetts,
Public Document No. 34.
Coberly, C. H. 1957. Measuring Sewage Flow from Schools. Public
Works, 88(5): 143.
Cohen, S. and H. Wallman. 1974. Demonstration of Waste Flow Reduction
from Households. EPA-670/2-74-071, United States Environmental
Protection Agency, Cincinnati, Ohio.
Commission on Rural Water. 1973. Water and Wastewater Problems in Rural
America, Washington, D.C.
Commission on Rural Water. 1974. Guide to State and Federal Policies
and Practices in Rural Water-Sewer Developr-ient. Washington, D.C.
Converse, J. C. 1974. Distribution of Domestic Waste Effluent in Soil
Absorption Beds. Trans ASAE, 17:299-309.
Converse, J. C., J. L. Anderson, W. A. Ziebell, and J. Bouma. 1975a. Pres-
sure Distribution to Improve Soil Absorption Systems. In: Home Sewage
Disposal, Proceedings of the National Home Sewage Disposal Symposium,
ASAE Pub. Proc. 175. St. Joseph, Michigan, pp. 104-115.
Converse, J. C., R. J. Otis, J. Bouma, W. G. Walker, J. L. Anderson and
D. E. Stewart. 1975b. Design and Construction Procedures for Mounds
in Slowly Permeable Soils With or Without Seasonally High Water Tables.
Small Scale Waste Management Project, University of Wisconsin, Madison,
Wisconsin (Revised March, 1976). »
Converse, J. C., R. J. Otis and J. Bouma. 1975c. Design and Construction
Procedures for Fill Systems in Permeable Soils With High Water Tables.
Small Scale Waste Management Project, University of Wisconsin, Madison,
Wisconsin. (Revised March, 1976).
Converse, J. C., R. J. Otis and J. Bouma. 1975d. Design and Construction
Procedures for Fill Systems in Permeable Soils With Shallow Creviced
or Porous Bedrock. Small Scale Waste Management Project. University
of Wisconsin, Madison, Wisconsin. (Revised March, 1976).
Cooper, I. A. and J. W. Rezek. 1977. Septage Treatment and Disposal.
In: Alternatives for Small Scale Wastewater Treatment Systems.
EPA-625/4-77-011. Environ. Prot. Agency. Tech. Trans., Cincinnati,
Ohio. pp. 61-90.
-94-
-------
Cooney, M. K., C. E. Hall, and J. P. Fox. 1972. The Seattle Virus
Watch. Ill, Evaluation of Isolation Methods and Summary of
Infections detected by Virus Isolations. Am. J. Epidemiol.
96:286-305.
Cotlove, E., V. Trantham, and R. L. Bowman. 1958. An Instrument for and
Method for Automatic, Rapid, Accurate and Sensitive Titration of
Chloride in Biological Samples. J. Lab. Clin. Med. 50:358-371.
Coulter, J. B., S. Soneda and M. B. Ettinger. 1957. Anaerobic Contact
Process for Sewage Disposal. Sewage and Industrial Wastes. 29(4):
468.
Crabtree, K. T. 1972. Nitrate and Nitrite in Ground Water. Technical
Bull. 58, Wis. Dept. Nat. Res., Madison, Wisconsin.
Craun, G. F. 1975. Microbiology—Waterborne Outbreaks. J. Water Pollut.
Control Fed. 47:1566-1580.
Craun, G. F. and L. J. McCabe. 1973. Review of the Causes of Water-
Borne Disease Outbreaks. J. Water Works Assoc. 65:74-84.
Daniel, T. C. and J. Bouma. 1974. Column Studies of Soil Clogging in a
Slowly Permeable Soil as a Function of Effluent Quality. J. Environ.
Qual. 3:321-326.
Daniels, R. B., E. E. Gamble and S. W. Buol. 1973. Oxygen Content in the
Ground Water of Some North Carolina Aquilts and Udults. In; Field
Soil Water Regime, SSSA Special Publication No. 5. Soil Sci. Amer.
Madison, Wisconsin, p. 153-166.
Daniels, R. B., E. E. Gamble and L. A. Nelson. 1971. Relations Between
Soil Morphology and Water-Table Levels on a Dissected North Carolina
Coastal Plain Surface. Soil Sci. Soc. Amer. Proc. 35:781-784.
Darcy, H. 1856. Les Fontaines Publique de la Ville de Dijou. Dalmont,
Paris.
Davenport, L. A., W. D. Lembke and B. A. Jones, Jr. 1975. Denitrification
in Laboratory Sand Columns. Trans. ASAE 18:95-99, 105.
Davies, T. R. and W. A. Pretorius. 1975. Denitrification with a Bacterial
Disc Unit. Water Res. 9:459-463.
Decoster, E. L. 1976. The Hydrodynamics of an Artificial Groundwater
Mound Developed as Part of a Subsurface Waste Disposal System.
M.S. Independent Study Report, Department of Civil and Environmental
Engineering, University of Wisconsin, Madison, Wisconsin.
-95-
-------
Deininger, J. F. 1977. Chemical Disinfection Studies of Septic Tank
Sludge with Emphasis on Formaldehyde and Glutaraldehyde,
M.S. Thesis, University of Wisconsin, Madison, Wisconsin,
de Vries, J. 1972. Soil Filtration of Wastewater Effluent and the
Mechanism of Pore Clogging. J. Water Pollut. Control Fed. 44:
565-573.
Doner, H. E., M. G. Volz and A. D. McLaren. 1974. Column Studies of
Denitrification in Soil. Soil Biol. Biochem. 6:341-346.
Doyle, C. B. 1967. Effectiveness of High pH for Destruction of
Pathogens in Row Sludge Filter Cake. J. Water Poll. Control
Fed., 39:1403.
Drewry, W. A. and R. Eliassen. 1968. Virus Movement in Groundwater.
J. Water Pollut. Control Fed. 40:257-271.
Duboise, S. M., B. P. Sagic, B. E. D. Moore, and J. F. Malina, Jr.
1974. Virus Migration Through Soils, p. 233-240. In: J. F. Malina,
Jr. and B. P. Sagic (eds.), Virus Survival in Water and Wastewater
Systems. Water Resources Symp. no. 7, Univ. of Texas, Austin.
Dudley, J. G. and D. A. Stephenson. 1973. Nutrient Enrichment of Ground-
water from Septic Tank Disposal Systems. Inland Lake Renewal and
Shoreland Management, Upper Lakes Commission Project Report.
Univ. of Wis., Madison, Wisconsin.
Dugan, G. L., R. H. F. Young, L. S. Lau, P. C. Eckern, and P. C. S.
Loh. 1975. Land Disposal of Wastewater in Hawaii. J. Water Pollut.
Control Fed. 47:2067-2087.
Eckenfelder, W. W. Jr. 1960. Application of Kenetics of Activated Sludge
to Process Design. In: Biological Waste Treatment. Proceedings of
the Third Conference on Biological Waste Treatment, W. E. Eckenfelder,
Jr. and J. McCabe, eds. McMillan Co., New York, New York.
Eckenfelder, W. and E. Barnhart. 1962. Synthetic Detergent Removal from
Laundry Wastes. Water and Sewage Works, Vol. 109, Reference Number
R341.
Eisenbeis, R. A. and R. B. Avery. 1972. Discriminant Analysis and
Classification Procedures. D. C. Heath and Company, Lexington,
Massachusetts.
Elek, S. D. 1959. Staphylococcus pyogenes and Its Relation to Disease.
E and S, Livingstone Ltd., London.
-96-
-------
Eliassen, R, and G. E, Bennett. 1967. Anion Exchange and Filtration
Techniques for Wastewater Renovation. Jour. Water Pollution
Control Federation, 39 (10 Part 2).
Eliassen, R. and W. A. Drewry. 1965. A Laboratory Study of Virus Movement
Through Soils, p. 97-110. In: Proc. Symp. Water Pollut. Control, Vol.
3. Nagpur.
Eliassen, R. and G. Tchobanoglous. 1968. Removal of Nitrogen and Phosphorus.
Presented at 23rd Purdue Industrial Waste Conf., Lafayette, Indiana.
22 p.
Eliassen, R., B. M. Wyckoff and C. D. Tonkin. 1965. Ion Exchange for
Reclamation of Reusable Supplies. J. American Water Works Assn.,
57:113.
Ellis, B. and K. E. Childs. 1973. Nutrient Movement From Septic Tanks and
Lawn Fertilization. Tech. Bull. 73-5. Mich. Dept. Nat. Res.,
Lansing, Michigan.
Emerson, D. L, Jr. 1945. Studies on Intermittent Sand Filtration of Sewage.
Bull. No. 9, Florida Engineering and Industrial Experiment Station,
University of Florida.
Engler, R. M. and W. H. Patrick, Jr. 1973. Sulfate Reduction and Sulfate
Oxidation in Flooded Soil as Affected by Chemical Oxidants. Soil Sci.
Soc. Amer. Proc. 37:685-688.
English, J. N., C. W. Carry, A. N. Masse, J. B. Pitkin and F. D. Dryden.
1974. Denitrification in Granular Carbon and Sand Colxunns. J. Water
Poll. Control Fed. 46:28-42.
Environment/One Corporation. 1972. Schenectady, New York.
Erickson, A. E., J. M. Tiedje, B. E. Ellis and C. M. Hansen. 1971.
A Barriered Landscape Water Reclamation System for Removing Phosphate
and Nitrogen From Feedlot Wastes. Proc. Int. Symp. on Livestock
Wastes, ASAE.
Evans, F. M. 1976. Department of Environmental Quality, Permits Section,
Des Moines, IA, personal communication.
Fair, G. M., J. C. Geyer and D. A. Okun. 1968. Water and Wastewater
Engineering, John Wiley and Sons, New York, Vol. II.
Farrell, J. B. 1974. Lime Stabilization of Primary Sludges. J. Water
Poll. Cont. Fed., 46:(113).
-97-
-------
Federick, J. C. 1948. Solving Disposal Problems in Unsewered Areas.
Sewage Works Engineering 19:292-293, 320.
Feherty, B. J. 1974. Outskirt Establishments Require Precise Water and
Sewage Designs. Water Pollution Control, 112(12)-.38.
Feige, W. A., E. T. Oppelt, J. F. Kreissl. 1975. An Alternate
Septage Treatment Method: Lime Stabilization/Sand-Bed Dewatering.
USEPA, EPA 600/2-75-036. National Technical Information Service,
Springfield, Virginia.
Flynn, J. M. and B. Andres. 1963. Laundrette Waste Treatment Processes.
Journal of the Water Pollution Control Federation, 35(6):783.
Forkner, C. E. Jr. 1960. Pseudomonas aeruginosa Infections. Grune and
Stratton, New York.
Francis, C. W. and M. W. Callahan. 1975. Biological Denitrification and
Its Application in Treatment of High-Nitrate Waste Waters.
J. Environ. Qual. 4:153-163.
Fuller, D. M. 1975. Head, Sewer Design Section, County Sanitation
Districts of Los Angeles County, personal communication.
Fuller, J. E. 1952. Detergents and Septic Tanks. Journal Sewage and
Industrial Wastes, 24 (7):844.
Geldreich, E. E. 1970. Applying Bacteriological Parameters to Recreational
Quality. J. Amer. Water Works Assn. 62:113-120.
Geldreich, E. E., R. H. Bordner, C. B. Huff, H. F. Clark, and P. W. Kabler.
1962. Type Distribution of Coliform Bacteria in the Feces of Warm-
Blooded Animals. J. Water Pollut. Control Fed. 34:295-301.
Geldreich, E. E., H. F. Clark, and C. B. Huff. 1964. A Study of Pollution
Indicators in a Waste Stabilization Pond. J. Water Pollut. Control
Fed. 36:1372-1379.
Georgetown Divide Public Utility District. 1972. Septic Tank Maintenance
District Implementation. Section VI, El Dorado County, California.
Gerba, C. P., C. Wallis, and J. L. Melnick. 1975. Fate of Wastewater
Bacteria and Viruses in Soil. J. Irrigation and Drainage Div. Amer.
Soc. Civ. Eng. 101:157-174.
Glasser, M. B. 1974. Garrett County Home Aeration Wastewater Treatment
Project, Bureau of Sanitary Engineering, Maryland State Department
of Health and Mental Hygiene, Baltimore, Maryland.
-------
Glueckert, A. J. and Saigh. 1975. Onshore Treatment System for Sewage
from Watercraft Retention Systems. NTIS-PB 239 630.
Goldsmith, J., D. Zohar, Y. Argaman, and Y. Kott. 1973. Effect of
Dissolved Salts on the Filtration of Coliform Bacteria in Sand Dunes,
p. 147-157. In: S. H. Jenkins (ed.), Advances in Water Pollution
Research. Pergamon Press, New York.
Goldstein, S. N. and W. J. Moberg. 1973. Wastewater Treatment Systems
for Rural Communities, Commission on Rural Water, National Demonstra-
tion Water Project, Washington, D.C., pp. 39-42.
Green, K. M. 1976. Sand Filtration for Virus Purification of Septic Tank
Effluent. Ph.D. Thesis, Department of Bacteriology, University of
Wisconsin, Madison, Wisconsin.
Green, K. M. and D. 0. Oliver. 1975. Removal of Virus from Septic Tank
Effluent by Sand Columns. In: Home Sewage Disposal: Proceedings of
the National Home Sewage Symposium, ASAE Pub. Proc. 175: St. Joseph,
Michigan, pp. 137-143.
Griffin, R. A. and J. J. Jurinak. 1974. Kinetics of the Phosphate Inter-
action with Calcite. Soil Sci. Soc. Amer. Proc. 38:75-79.
Groundwater Contamination. 1961. Tech. Report W61-5, Robert A. Taft San.
Eng. Cent. Cincinnati, Ohio.
Gruener, N. and H. I. Shuval. 1969. Health Aspects of Nitrates in
Drinking Water. In: Developments in Water Quality Research, H. I.
Shuval (ed.) Proceedings of the Jerusalem International Conference on
Water Quality and Pollution Research.
Haenel, H. 1961. Some Rules in the Ecology of the Intestinal Microflora
of Man. J. Appl. Bact. 24:242-251.
Hall, H. E., and G. H. Hauser. 1966. Examination of Feces from Food Handlers
for Salmonellae, Shigellae, Enteropathogenic Escherichia coli and
Clostridium perf ringens. Appl. Microbiol. 14:928-933.
Harkin, J. M. U.S. Patent No. 4,021,338. 1977. Assigned to Wisconsin
Alumni Research Foundation, Madison, Wisconsin.
Harkin, J. M. and S. K. Iskandar. 1977. Unpublished data. Department
of Soil Science, University of Wis., Madison, Wisconsin.
Harkin, J. M. and K. D. Jawson. 1976. Clogging and Unclogging of Septic
System Seepage Beds. Proceedings Second Illinois Private Sewage Dis-
posal System, Illinois Department of Public Health, Champaign,
Illinois, p. 11-21.
-99-
-------
Harkin, J. M., M. D. Jawson and F. G. Baker. 1976. Causes and Remedy of
Failure of Septic Tank Seepage Systems. Proceedings Second National
Conference on Individual Onsite Wastewater Systems, National Sanitation
Foundation. Ann Arbor, Michigan, p. 119-121.
Hayashida, K. 1975. Director and Chief Engineer, City Engineer, City and
County of Honolulu, Hawaii, personal communication.
Hayat, M. A. 1970. Principals and Techniques of Electron Microscopy:
Biological Applications, Vol. I. Van Nostrand Reinhold Co., New York,
NY, 412 pp.
Hazardous Materials Advisory Committee. 1973. Nitrogenous Compounds in the
Environment. U.S. Environ. Prot. Agency, Wash. D.C. EPA-SAB-75-001.
Hazen, A. 1892. Some Physical Properties of Sands and Gravels. Report
to the Massachusetts State Board of Health, 550.
Healy, K. A. and R. Laak. 1974. Site Evaluation and Design of Seepage
Beds. J. Environ. Eng. Division, ASCE, EE5, Proc. Paper 10882
100:1133-1146.
Herrmann, J. E. and D. 0. Cliver. 1973. Rapid Method to Determine Labeling
Specificity of Radioactive Enteroviruses. Appl. Microbiol. 25:313-314.
Herruhut, H. and E. Bosshard. 1974. First Gamma-Irradiation Plant for
Sewage Sludge Hygienization. Sulzer Tech. Rev. (Switz) 56:77.
Hess, E. and C. Breer. 1975. Salmonell-enepidemiologie und Grund land
dungung mit Klarschlamm. Abl. Bakt. Hyg., I. Abt. Orig. B, 161:54.
Hill, D. C. 1966. Percolation Testing for Septic Tank Drainage.
Bulletin of Connecticut Agr. Exp. Station. New Haven, Connecticut,
No. 678.
Hillel, D. I. 1971. Soil and Water: Physical Principles and Processes.
New York: Academic Press, 288 p.
Hillel, D. I., V. D. Krentos, and Y. Staylianon. 1972. Procedure and
Test of An Internal Drainage Method for Measuring Soil Hydraulic
Characterisitcs in situ. Soil Sci. 114:395-400.
Mines, M. and Favreau. 1974. Recirculating Sand Filter: An Alternative
to Traditional Sewage Absorption Systems. Proceedings - National
Home Sewage Disposal Symposium, ASAE, Chicago, Illinois.
Hoadley, A. W. and E. McCoy. 1968. Some Observations on the Ecology
of Pseudomonas aeruginosa and Its Occurrence in the Intestinal
Tracts of Animals. Cornell Vet. 58:354-363.
-100-
-------
Hoadley, A. W., E. McCoy, and G. A. Rohlich. 1968. Untersuchungen uber
Pseudotnonas aeruginosa in Coerflachengewassern. I. Quellen. und II.
Auftreten and Verhalten. Arch Hyg. Bakt. 152:328-338; 339-345.
Hori, D. H., N. C. Burbank, R. H. F. Young, L. S. Lau, and H. W. Klemmer.
1971. Migration of Poliovirus Type II in Percolating Water through
Selected Oahu Soils, p. HA11/1-10. In: S. H. Jenkins (ed.),
Advances in Water Pollut. Research, Vol. 2. Pergamon Press, N.Y.
Howe, R. S. 1961. Operational Problems of Package Activated Sludge Plants.
Jour. Water Pollution Control Federation, 33(11):1166.
Hsu, P. H., and D. A. Rennin. 1962. Reactions of Phosphate in Aluminum
Systems. I. Adsorption of Phosphate by X-ray Amorphorus "Aluminum
Hydroxide". Can. J. Soil Sci. 42:197-209.
Hubbell, J. W. 1962. Commercial and Institutional Wastewater Loadings.
Journal of the Water Pollution Control Federation, 34(9):962.
Huff, C. B. 1965. Study of UV Disinfection of Water and Factors in
Treatment Efficiency. Public Health Reports, 80(8):695.
Hunter, R. B. 1940. Methods of Estimating Loads on Plumbing Systems.
Report BMS 65, National Bureau of Standards, Washington, D.C.
Hunter, R. B. 1941. Water Distribution Systems for Buildings.
Report BMS 79, National Bureau of Standards, Washington, D.C.
Hutzler, N. J. 1974. Evaluation of On-Site Wastewater Treatment Processes.
M.S. Independent Study Report, Department of Civil and Environmental
Engineering, University of Wisconsin, Madison, Wisconsin.
IAPMO UPC. 1976. Uniform Plumbing Code. International Association of
Plumbing and Mechanical Officials. Los Angeles, California.
Jackson, M. L. 1958. Soil Chemical Analysis, Prentice-Hall International
Inc., Englewood Cliffe.
Jawson, M. D. 1976. Soil Clogging by Septic Tank Effluent: Causes;
Methods of Correction. M.S. Thesis. Department of Soil Science,
University of Wisconsin, Madison, Wisconsin.
Jankins, D. 1960. The Use of Manometric Methods in the Study of Sewage
and Trade Wastes. In; Waste Treatment, C. G. Issac, ed. , Pergamon
Press, New York, New York.
Jeris, J. S. 1975. High Rate Biological Denitrification. Jour. Water
Pollution Control Federation, 47(8):2043.
-101-
-------
Jones, J. H. and G. S. Taylor. 1965. Septic Tank Effluent Percolation Through
Sands Under Laboratory Conditions. Soil Science 99:301-309.
Jorgensen, S. E., 0. Libor, K. Lea Graber, K. Barkacs. 1976. Ammonia Removal
By Use of Clinoptilolite. Water Research, 10:213.
Keeney, D. R. and J. M. Bremner. 1965. Determination of Inorganic Forms of
Nitrogen in Soils. I. Exchangeable Ammonium, Nitrate and Nitrite.
Soil Sci. Soc. Amer. Proc. 30:583-587.
Klessig, L. and D. A. Yanggen. 1974. Town Sanitary Districts in Wisconsin:
Their Legal Powers, Characteristics and Activities. University of
Wisconsin Extension, Madison, Wisconsin.
Klock, J. W. 1973. Professor of Engineering, School of Engineering,
Arizona State University, Tempe, Arizona, personal communication.
Kloos, W. E. and K. N. Schleifer. 1975. Isolation and Characteriz-
ation of Staphylococci from Human Skin. II. Description of Four New
Species: Staphylococcus warneri, Staphylococcus capitus, Staphylococcus
hominus, and Staphylococcus simulas. Internat'l. J. Systematic
Bacteriol. 25:62-79.
Klute, A. 1965. Laboratory Measurements of Hydraulic Conductivity of
Unsaturated Soil. In: Methods of Soil Analysis, C. A. Black, ed.,
Agr. 9:253-261.
Kolzow, W. C. 1975. Sanitary Engineer, U.S. Department of Agriculture-Forest
Service, personal communication.
Konen, T. P. 1976. European Plumbing Practices: Incentives for Change.
Presented in the Proceedings of An Urban Water Conservation Conference
sponsored by the California Department of Water Resources in Los
Angeles California on January 16-17, 1976.
Koon, J. H. and W. J. Kaufman. 1971. Optimization of Ammonia Removal by
Ion Exchange Using Clinoptilolite. Sanitary Engineering Research Lab-
oratory, University of California, Berkeley, Cal., SERL Report No. 71-5.
Kropf, F. W., K. A. Healey and R. Laak. 1975. Soil Clogging in Subsurface
Absorption Systems for Liquid Domestic Wastes. Progress in Water
Technology 7:767-774.
Kropf, F. W., R. Laak, K. A. Healey. 1977. Equilibrium Operation of Subsurface
Absorption Systems. Jour. Water Poll. Control Fed. 49:2007-2016.
Kulesze, T. J. 1975. Chief of the Industrial Waste Unit, City of Philadelphia
Water Department, personal communication.
-102-
-------
Kuo, S. and E. G. Lotse. 1973. The Kinetics of Phosphate Adsorption and
Desorption by Hematite and Gibbsite. Soil Sci. 116(b):406.
Laak, R. 1970. Influence of Domestic Wastewater Pretreatment on Soil
Clogging. J. Water Pollution Control Federation, 12:1495-1500.
Laak. R. 1973. Eastewater Disposal Systems in Unsewered Areas. Final
Report to Connecticut Research Commission, Civil Engr. Dept.,
Univ. of Conn. Storrs, Conn.
Laak, R. 1975. Relative Pollution Strengths of Undiluted Waste Materials
Discharged in Households and the Dilution Waters Used for Each, as
presented in Manual of Grey Water Treatment Practice, Ann Arbor Science,
Ann Arbor, Michigan.
Laak, R. 1976. Pollutant Load from Plumbing Fixtures and Pretreatment to
Control Soil Clogging. J. Environ. Health 39:48-50.
Lance, J. C., C. P. Gerba, and J. L. Melnik. 1976. Virus Movement in Soil
Columns Flooded with Secondary Sewage Effluent. Applied Environ. Micro.
32:520-526.
Lefler, E., and Y. Kott. 1973. Enteric Virus Behavior in Sand Dunes,
p. A73-A91. In: Proc. 4th Scientific Conf. of the Israel Ecological
Soc., Tel-Aviv.
Lefler, E., and Y. Kott. 1974. Virus Retention and Survival in Sand.
p. 84-91. In; J. F. Malina, Jr. and B. P. Sagic (eds.), Virus
Survival in Water and Wastewater Systems. Water Resources Symp. no. 7.
Univ. of Texas, Austin.
Ligman, K. 1972. Rural Wastewater Simulation. Thesis presented to the
University of Wisconsin at Madison, Wisconsin in partial fulfillment
of the requirements for the degree of Master of Science.
Ligman, K., N. Hutzler, and W. C. Boyle. 1974. Household Wastewater
Characterization. Journal of the Environmental Engineering Division,
ASCE, Vol. 100, No. EE1, Proc. Paper 10372.
Linaweaver, F. P., J. C. Geyer and J. B. Wolff. 1967. A Study of Residential
Water Use. U.S. Department of Housing and Urban Development.
Lindsay, W. L. and E. C. Moreno. 1960. Phosphate Phase Equilibria in Soils.
Soil Sci. Soc. Amer. Proc. 24:117-182.
Luce, H. D. 1973. Soil Factors Influencing Percolation Test Performance
of Some Iowa Soils. Unpublished M.S. Thesis. Iowa State University,
Ames, Iowa.
-103-
-------
Ludwig, H. F. 1949. Septic Tank Performance Under Surge Flow Conditions.
Water and Sewage Works, 96(3):122.
Ludwig, H. F. 1950. Septic Tanks - Design and Performance. Sewage and
Industrial Wastes, 22(1):55.
Ludwig, H. F., W. J. Oswals and H. B. Gotaas. 1951. Manometric Technique
for Measurement of BOD. Institute of Engineering Research, University
of California, Berkeley, California.
Luft, J. N. 1976. Personal communication. University of Washington,
Seattle.
McCabe, J. 1960. Mathematical Formulation of the Biological Oxidation
Process. In: Advances in Biological Waste Treatment. Proceedings
of the Third Conference on Biological Waste Treatment. W. E.
Eckenfelder, Jr. and J. McCabe, eds., Manhattan College, New York,
McMillan Company, New York, New York.
McCalla, T. M. 1945. Influence of Microorganisms on Some Organic Substances
on Soil Structure. Soil Science 59:287-297.
McCalla, T. M. 1946. Influence of Microorganisms on Some Organic Substances
on Water Percolation Through a Layer of Peorian Loess. Soil Science
of America Proceedings. 10:175-179.
McCalla, T. M. 1950. Studies on the Effect of Microorganisms on Rate of
Percolation of Water Through Soils. Soil Science Society of America
Proceedings. 15:182-186.
McCarty, P. L., L. Beck and P. P. St. Amant. 1969. Biological Denitrifica-
tion of Waste Waters by Addition of Organic Materials. Proc. 24th Ind.
Waste Conf., Lafayette, In. p. 1271-1285.
McCarty, P. L. and R. T. Haug. 1971. Nitrogen Removal from Wastewater
by Biological Nitrification and Denitrification, p. 215-232.
In; G. Sykes and F. A. Skinner (ed.) Microbial Aspects of Pollution.
Academic Press, London.
McClelland, N. I. 1976. NSF Programs Relating to Individual Onsite
Wastewater Disposal. Presented at Northwest Onsite Wastewater
Disposal Short Course, University of Washington, Seattle, Washington.
McCormack, D. E., and L. P. Wilding. 1969. Variation of Soil Properties
Within Mapping Units of Soils With Contrasting Substrate in Northwestern
Ohio. Soil Sci. Soc. Amer. Proc. 33:587-593.
-104-
-------
McCoy, E. and W. A. Ziebell. 1976. The Effects of Effluents on Groundwater-
Bacteriological Aspects. In: Second National Conference on Individual
Onsite Wastewater Systems. National Sanitation Foundation. Ann Arbor,
Michigan, pp. 67-76.
McCuen, R. H., R. C. Sutherland and J. R. Kim 1975. Forecasting Urban Water
Use: Commercial Establishments. Journal of the American Water Works
Association, 65(5):239.
McLaren, J. R. and G. J. Farquhar. 1973. Factors Affecting Ammonia Removal
by Clinoptilolite. Jour. Environ. Engineering Division, A.S.C.E.,
99:429.
McGauhey, P. H. and R. B. Krone. 1967. Soil Mantle as a Wastewater Treatment
System. Final report. SERL Report No. 67-11. Sanitary Engineering
Research Laboratory, University of California, Berkeley, California.
McGauhey, P. H. and J. H. Winneberger. 1964. Causes and Prevention of
Failure of Septic Tank Percolation Systems. Technical Studies Report
No. 533, Federal Housing Administration, Washington, B.C.
McGauhey, P. H. and J. H. Winneberger. 1965. A Study of Methods of Preventing
Failure of Septic Tank Percolation Systems. Final report. SERL Report
No. 67-17. Sanitary Engineering Research Laboratory, University of
California, Berkeley, California.
Macgregor, A. N. and D. R. Keeney. 1973. Methane Information by Lake
Sediments During in vitro Incubation. Water Res. Bull. 9:1153-1158.
Machmeier, R. E. 1975. Design Criteria for Soil Treatment Systems.
Scientific Jour. Series Paper No. 9358. Minn. Agricul. Exper. Sta.,
St. Paul, Minn.
Mack, W. N., Y. S. Lu, and D. B. Coohon. 1972. Isolation of Poliomyelitis
Virus from a Contaminated Well. Health Services Reports 87:271-274.
McMichael, F. C. and J. E. McK.ee. 1965. Research on Wastewater Reclamation
at Whittier Narrows. California Water Quality Control Board, Sacramento.
Magdoff, F. R. and J. Bouma. 1974. The Development of Soil Clogging in Sands
Leached with Septic Tank Effluent. In: Home Sewage Disposal Proceedings
of the National Home Sewage Disposal Symposium, ASAE Publication Proc.
175, St. Joseph, Michigan, pp. 37-47.
Magdoff, F. R., J. Bouma and D. R. Keeney. 1974a. Columns Representing
Mound-Type Disposal Systems for Septic Tank Effluent: I. Soil-Water
and Gas Relationships. J. of Environ. Qual. 3:223-228.
-105-
-------
Magdoff, F. R. and D. R. Keeney. 1976. Nutrient Mass Balance in Columns
Representing Fill Systems for Disposal of Septic Tank Effluents.
Environ. Lett. 10:285-294.
Magdoff, F. R., D. R. Keeney, J. Bouma, and W. A. Ziebell. 1974b. Columns
Representing Mound-Type Disposal Systems for Septic Tank Effluent.
II. Nutrient Transformations and Bacterial Populations. J. Environ.
Qual. 3:228-234.
Mann, L. D., D. D. Focht, H. A. Joseph and L. H. Stolzy. 1972. Increased
Denitrification in Soils by Additions of Sulfur as an Energy Source.
J. Environ. Qual. 1:329-332.
Mason, D. D., J. F. Lutz and R. G. Petersen. 1957. Hydraulic Conductivity
as Related to Certain Soil Properties in a Number of Great Soil Groups,
Sampling Errors Involved. Soil Sci. Soc. Amer. Proc. 21:554—560.
May, R. 1975. Sanitary Engineer for the State of Connecticut Department
of Environmental Protection, personal communication.
1'ercer, B. W. , L. L. Ames, C. J. Touhill, C. J. Van Slyke, R. B. Dean. 1970.
Ammonia Removal from Secondary Effluents by Selective Ion Exchange.
Jour. Water Pollution Control Federation, 42(2, Part 2): R95.
Merrell, J. C., Jr., W. F. Jopling, R. F. Bott, A. Katko, and H. E. Pintler.
1967. Santee Recreation Project, Santee, California. U.S.D.I. Water
Pollution Control Research Series Publ. WP-20-7.
Metcalf, L. and H. P. Eddy. 1935. American Sewage Practice, Vol. Ill,
McGraw-Hill Co., New York, NY.
Metcalf and Eddy, Inc., 1972. Wastewater Engineering, McGraw-Hill, New York,
NY, p. 29.
Millar, H. C., F. B. Smith and P. E. Brown. 1936. The Rate of Decomposition
of Various Plant Materials in Soils. J. Amer. Soc. Agron. 28:914-929.
Miller, J. C. 1972. Nitrate Contamination of the Water Table Aquifer in
Delaware. Rept. 20, Delaware Geol. Survey, Newark, Delaware.
Milne, M. 1976. Residential Water Conservation. California Water Resource
Center Rept. No. 35. University of California - Davis.
Mitchell, R. and Z. Nevo. 1964. Effect of Bacterial Polysaccharide Accumula-
tion on Infiltration of Water Through Sand. Applied Microbiology
12:219-223.
Monod, J. 1950. La Technique de Culture Continue Theorie et Applications.
Ann. Inst. Pasteur 79:390-410.
-106-
-------
National Academy of Sciences. 1972. Accumulation of Nitrate. Committee
on Nitrate Accumulation, National Res. Council. Wash., B.C.
National Sanitation Foundation. 1966. Package Plants Criteria Development,
Part I: Extended Aeration, Ann Arbor, Michigan.
National Sanitation Foundation. 1970. Standard No. 40: Individual Aerobic
Wastewater Treatment Plants. Ann Arbor, Michigan.
National Sanitation Foundation. 1972. Test Results. Ann Arbor, Michigan.
Nelson, J. 0. 1976. North Marin's Little Compendium of Water-Saving Ideas,
North Marin County Water District, Novato, California.
Nero, D. N. 1974. A Survey of Domestic Wastewater for Salmonellae.
M.S. Thesis. Department of Bacteriology, University of Wisconsin,
Madison.
Nestor, I., and L. Costin. 1971. The Removal of Coxsackie Virus from Water
by Sand Obtained from the Rapid Sand Filters of Water-Plants.
J. Hyg. Epidemiol. Microbiol. and Immunol. 15:129-136.
Nielsen, D. R., J. W. Biggar and K. T. Erh. 1973. Spacial Variability
of Field-Measured Soil-Water Properties. Hilgardia, Vol. 42. No. 7,
pp. 215-259.
Noack, D. and G. Burger. 1974. Disinfecting Sewage Sludge. German Patent
No. 97, 640, Chem Abs 80:14, 74081E.
Norwegian Department of the Environment. 1975. Forskrifter for Kloakkutslipp
fra Spredt Bolig-og Fritidsbebyggelse. Oslo, Norway.
Nottingham, M. C., H. F. Ludwig. 1948. Septic Tank Performance Related to
Tank Length, Width and Depth, Water and Sewage Works, 95(12) :460.
Novak, L. T., and D. C. Adriano. 1975. Phosphorus Movement in Soils:
Soil-Orthophosphate Reaction Kinetics. J. Environ. Qual. 4:261-266.
Nuclear Chicago Corporation. 1957. Preliminary Instruction Manual for Model
P-19 Moisture Probe and Model 7800 Sealer. Chicago, Illinois.
Olsson, E., L. Karlgren and V. Tullander. 1968. Household Wastewater, Report
24:1968, The National Swedish Institute for Building Research, Stockholm,
Sweden.
Otis, R. J. 1977. Onsite Wastewater Facilities for Small Communities and
Subdivisions. In: Individual Onsite Wastewater Systems. N..I.
McClelland (ed.T~ Ann Arbor Science, Ann Arbor, Michigan, pp. 245-275.
Otis, R. J., J. Bouma and W. G. Walker. 1974. Uniform Distribution in Soil
Absorption Fields. Ground Water 12:409-417.
-107-
-------
Otis, R. J. and W. C. Boyle. 1976. Performance of Single Household Treatment
Units. Journal Environmental Engineering Division. ASAE. Proc. Paper
11895 102:175-189.
Otis, R. J., W. C. Boyle, D. R. Sauer. 1975. The Performance of Household
Wastewater Treatment Units Under Field Conditions. In: Home Sewage
Disposal Proc. National Home Sewage Disposed. Symposium, Amer. Soc. Agr.
Eng, Pub. Proc-175, St. Joseph, Michigan, pp. 191-201.
Otis, R. J., J. C. Converse, B. L. Carlile, and J. E. Witty. 1977.
Effluent Distribution. In; Home Sewage Treatment, ASAE Publication
5-77, St. Joseph, Michigan, pp. 61-85.
Otis, R. J. and D. E. Stewart. 1976. Alternative Wastewater Facilities for
Small Unsewered Communities in Rural America. Small Scale Waste
Management Project, University of Wisconsin, Madison.
Parr, J. F. and A. G. Norman. 1964. Growth and Activity of Soil Micro-
organisms in Glass Micro-beads: I. Carbon Dioxide Evolution.
Soil Sci. 97:361-366.
Patrick, W. M., Jr. 1964-. Extractable Iron and Phosphorus in a Submerged
Soil at Controlled Redox Potentials. 8th International Conf. of Soil
Sci., Bucharest, Rumania. IV. pp. 605-609.
Patrick, W. H. and I. C. Mahaptra. 1968. Transformations and Availability
to Rice and Phosphorus in Waterlogged Soils. Adv. Agron. 20:323-359.
Patterson, D. H. 1977. Residential Sewage Disposal Survey. Indiana State
Board of Health. Indianapolis, Indiana.
Patterson, J. W., R. A. Minear and T. K. Nedved. 1971. Septic Tanks and
the Environment. Illinois Institute for Environmental Quality,
Chicago, Illinois. National Technical Information Service Publication
No. PB-204 519. U.S. Dept. of Commerce.
Pearson, F. H. and J. B. Nesbitt. 1975. Wastewater Flow From Sports
Spectators, Journal of the Environmental Engineering Division, ASCE, 101
(EE2): 291.
Peck, T. J. 1962. The Evaluation of Available Phosphorus Tests for
Wisconsin Soils. Ph.D. Thesis, University of Wisconsin, Madison.
Perry, R. 1954. Adaptation of an Aerobic Sewage Treatment Process for
Individual Homes, Master of Science Thesis, 1952, as presented in
Summary of Studies on Aerobic Sewage Treatment for Individual Homes,
by Perry Rigby, et al., Unpublished Report, Purdue University, 1954.
-108-
-------
Perry, J. B. and R. F. Harris. 1975. Respirometric Evaluation of the
Decomposition Kinetics of Septic Effluent-Derived Clogging Agents in
Soil. Presented at American Society of Agronomy Annual Meeting,
Knoxville, Tennessee.
Pillai, N. N., W. C. Wheeler and R. P. Prince. 1971. An Operation of
Extended Aeration Plants, Jour. Pollution Control Federation, 43(7):1484.
Plews, G. D. 1977. The Adequacy and Uniformity of Regulations for On-Site
Wastewater Disposal. In: Less Costly Wastewater Treatment Systems for
Small Communities. U.S. Environmental Protection Agency. Municipal
Environmental Research Laboratory, Cincinnatti, Ohio.
Polkowski, L. B., and W. C. Boyle. 1970. Ground Water Quality Adjacent
to Septic Tank-Soil Absorption Systems. Wis. Dept. Natr. Res.,
Madison. 75 p.
Polta, R. C. 1969. Septic Tank Effluents. Univ.' Minn. Water Res. Center
Bull. 13:53-57. Minneapolis.
Posner, H. S. 1975. Biohazards of Methanol in Proposed New Uses.
J. Toxicol. Environ. Health 1:153-171.
Frier, J. E., and H. Friedman (eds) 1974. Opportunistic Pathogens.
Univ. Park Press, Baltimore. 304 pp.
Pruel, H. C. 1966. Underground Movement of Nitrogen. In: Adv. Water
Pollut. Res., Proc. 3rd Intl. Conf. Water Pollut. Res., Water Pollut.
Conf. Fed. Wash., D.C. 1:309-327.
Pruel, H. C. and G. J. Schroepfer. 1968. Travel of Nitrogen in Soils.
J. Water Pollut. Conf. Fed. 40:30-48.
Quinn, E. L., F. Cox, and M Fisher. 1965. The Problem of Associating
Coagulas Negative Staphylococci with Disease. Ann, N.Y. Acad. Sci.
128:428-442.
Quispel, A. 1946. Measurement of the Oxidation-Reduction Potentials of
Normal and Inundated Soils. Soil Sci. 63:265-275.
Raats, P. A. C. and W. R. Gardner. 1971. Comparison of Empirical Relation-
ships Between Pressure Head and Hydraulic Conductivity and Some
Observation on Radially Symmetric Flow. Water Res. Research 7:921-928.
Ramon, V. and N. Chakladar. 1972. Upflow Filters for Septic Tank Effluents.
Jour. Water Pollution Control Federation, 44(8):1552.
Reeder, M. E. and W. J. Fogarty. 1964. Water and Sewage Flow Rates in
Public Schools. Public Works, 95(11):80.
Reid, G. W. 1976. An Exploratory Study of Possible Energy Savings as a
Result of Water Conservation Practices. Office of Water Research and
Technology, A-061-OKLA.
-109-
-------
Reid, L. C., Jr. 1971. Design of Wastewater Disposal Systems for Individual
Dwellings. Jour. Water Pollution Control Federation, 43(10): 2004.
Requa, D. A. and E. D. Schroeder. 1973. Kinetics of Packed-Bed Denitrifica-
tion. J. Water Poll. Control Fed. 45:1696-1707.
Ringler, D. W. 1975. Director of the Oakland County Department of Public
Works, Pontaic, MI, personal communication.
Robbins, J. H. and A. C. Green. 1974. Development of On-Shore Treatment
System for Sewage From Watercraft Waste Retention System, EPA-670/2-
74-056.
Robeck, G. C., T. W. Bendixen, W. A. Schwartz, and R. L. Woodward. 1964.
Factors Influencing the Design and Operation of Soil Systems for
Waste Treatment. J. Water Pollut. Control Fed. 36:971-983.
Robeck, G. G., N. A. Clarke, and K. A. Dostal. 1962. Effectiveness of
Water Treatment Processes in Virus Removal. J. Am. Water Works Assoc.
54:1275-1292.
Roberts, R. B., P. H. Abelson, D. B. Cowie, E. T. Bolton, and R. J. Britten.
1957. Studies of Biosynthesis in Escherichia coli. Carnegie Institu-
tion of Washington Publ. 607. Washington, D.C.
Rogowski, A. S. 1972. Watershed Physics: Soil Variability Criteria.
Water Res. Research 8:1015-1023.
Rose, C. W. 1966. Agricultural Physics. Pergaroon Press, Oxford.
Rudolfs, W., L. L. Falk, and R. A. Ragotzkie. 1950. Literature Review on
the Occurrence and Survival of Enteric, Pathogenic, and Related
Organisms in Soil, Water, Sewage, and Sludges, and on Vegetation.
Sewage Indus. Waste 22:1221-1281.
Rybczynski, W. and A. Ortega. 1975. Stop the Five Gallon Flush!
Minimum Cost Housing Group, School of Architecture, McGill University,
Montreal H3C 3G1, Canada.
Sabey, B. R. 1969. Influence of Soil Moisture Tension on Nitrate Accumula-
tion in Soils. Soil Sci. Soc. Amer. Proc. 33:263-266.
St. Amant, P. P. and L. A. Beck. 1970. Methods of Removing Nitrates From
Water. J. Agr. Food Chem. 18:785-788.
St. Louis Chip/Ecodyne Corp., 1974. FAST, No Discharge System. St. Louis,
MO.
Salo, R. J., and D. 0. Cliver. 1976. Effect of Acid ph, Salts, and Tempera-
ture on the Infectivity and Physical Integrity of Enteroviruses. Arch.
Virol. 52:269-282.
-110-
-------
Salvato, J. A. 1955. Experience With Subsurface Sand Filters.
Sewage and Industrial Wastes, 27(8) :909.
Salvato, J. A. 1972. Environmental Engineering and Sanitation. Wiley-
Inters cience, New York, NY, p. 128.
Santarone, J. E. 1976. Department of Environmental Regulation, State of
Florida, Montgomery Building, Tallahassee, Florida, personal communica-
tion.
Sauer, D. K. 1975. Intermittent Sand Filtration of Septic Tank and Aerobic
Unit Effluents Under Field Conditions. M.S. Thesis, University of
Wisconsin, Madison, Wisconsin.
Sauer, D. K., W. C. Boyle, and R. J. Otis. 1976. Intermittent Sand Filtration
of Household Wastewater Under Field Conditions. J. Environ. Eng. Ar. ,
ASCE 102, EE4.
Savage, E. S. 1974. Advances in Ammonia and Nitrate Removal: Biological
Nitrification and Denitrification. WWEMA Conf., Detroit, 14 pp.
Sawyer, C. N. 1965. Problems of Phosphorus in Water Supplies. J. Amer.
Water Works Assn. 57:1431.
Sawhney, B. L., and D. E. Hill. 1975. Phosphate Sorption Characteristics of
Soils Treated With Domestic Waste Water. J. Environ. Qual. 4:343-346.
Schaub, S. A., and B. P. Sagic. 1975. Association of Enteroviruses With
Natural and Artificially Introduced Colloidal Solids in Water and
Infectivity of Solids-Associated Virions. Appl. Microbiol. 30:212-222.
Schaub, S. A., C. A. Sorber, and G. W. Taylor. 1974. The Association of
Enteric Viruses With Natural Turbidity in the Aquatic Environment,
p. 71-83. In: J. F. Malina, Jr. and B. P. Sagic (ed.), Virus Survival
in Water and Wastewater Systems. Water Resources Symp. No. 7. Univ. of
Texas, Austin.
Schlater, J. and J. Learn. 1975. Discrim 1: Discriminant Analysis.
Reference Manual. Madison Academic Computing Center, University of
Wisconsin, Madison, Wisconsin.
Schleifer, K. N. and W. E. Kloos. 1975. Isolation and Characterization of
Staphylccoccus epidermidis and Staphylococcus saprophyticus and Descrip-
tions of Three New Species: Staphylococcus cohnii, Staphylococcus haemoly-
ticus, and Staphylococcus xylosus. Internatl. J. Systematic Bact.
25:50-61.
Scholten, A. E. 1965. The Reaction of Phosphate With Mineral Surfaces and
Ion Oxide Gels. Ph.D. Theses. University of Wisconsin, Madison.
-Ill-
-------
Schroeder, E. D. and A. J. Busch. 1968. The Role of Nitrate-Nitrogen in
Bio-Oxidation. JWPCF, 40, R445.
Schwartz, W. A., T. W. Benedixen and R. E. Thomas. 1967. Project Report
of Pilot Studies on the Use of Solids as a Waste Treatment Media.
In-house Report, Federal Vlater Pollution Control Agency, Cincinnati, Ohio.
Searcy, P. and T. deS. Furman. 1961. Water Consumption by Institutions.
Journal of the American Vlater Works Association, 53(9):1111.
Shah, J. 1976. Oakland County Department of Public Works. Pontiac, Michigan,
personal communication.
Shaw, R. 1970. Experiences with Waste Ordinances and Surcharges at
Greensboro, North Carolina. Journal Water Pollution Control Federation,
42(1): 44.
Sherman, H. C. 1952. Chemistry of Food and Nutrition. 8th ed., MacMillan
Co. , New York.
Shuval, H. I. 1970. Developments in Water Quality Research. Ann Arbor
Press, London.
Siegrist, R. 1975. Characterization of Rural Household Wastewaters.
Thesis presented to the University of Wisconsin at Madison, Wisconsin
in partial fulfillment of the requirements for the degree of Master of
Science.
Siegrist, R., M. Witt and W. C. Boyle. 1976. The Characteristics of Rural
Household Wastewater. ASCE, Proc. Paper 12200, 102:533-548.
Sikora, L. J. and D. R. Keeney. 1975., Laboratory Studies on Stimulation
of Biological Denitrification. Proc. Natl. Home Sewage Disposal
Symposium, ASAE, 64.
Sikora, L. J. and D. R. Keeney. 1976. Denitrification of Nitrified Septic
Tank Effluent. JWPCF 48(8):2018-2025.
Sikora, L. J. and R. B. Corey. 1976. Fate of Nitrogen and Phosphorus in
Soils Under Septic Tank Waste Disposal Fields. Trans. Amer. Soc.
Agr. Engr. 19:866-875.
Simonson, G. H. and L. Boersma. 1972. Soil Morphology and Water Table
Relations: II. Correlation Between Annual Water Table Fluctuations
and Profile Features. Soil Sci. Soc. Amer. Proc. 36:649-653.
-112-
-------
Sironew, E, 1976. Certification of Wastewater Treatment Plant Personnel.
Presented at the 49th Annual Water Poll. Cont. Fed. Conference.
Minneapolis, Minnesota.
Smith, H. W., and W. E. Crabb. 1961. The Faecal Bacterial Flora of Animals
and Man: Its Development in the Young. J. Path. Bact. 82:53-66.
Smith, J. M., A. N. Masse, W. A. Feige and L. J. Kamphake. 1972.
Nitrogen Removal From Municipal Waste Water by Columnar Denitrification.
Environ. Sci. Tech. 6:260-267.
Snedecor, B. and C. L. Cooney. 1974. Thermophilic Mixed Culture of Bacteria
Utilizing Methanol for Growth. Applied Microbiology, 27, 112.
Sobsey, M. D., C. Wallis, J. L. Melnick. 1974. Chemical Disinfection of
Holding Tank Sewage. Appl. Microbiology, 28:861.
Snedecor, G. W. and W. G. Cochran. 1967. Statistical Methods. 6th ed.
Iowa State University Press, Ames, Iowa, p. 329-330.
Soil Survey Staff. 1951. Soil Survey Manual. U.S. Department of
Agriculture, Handbook 18, Washington, D.C.
Soil Survey Staff. 1975. Soil Taxonomy. U.S. Department of Agriculture.
Handbook 436, Washington, D.C.
Standard Methods for the Examination of Water and Wastewater. 1965.
Twelth Edition, Washington, D.C. American Public Health Association.
Standard Methods for the Examination of Water and Wastewater. 1971.
13th Edition, American Public Health Assoc. Washington, D.C.
Stanford, G., and E. Epstein. 1974. Nitrogen Mineralization Water Relations
in Soils. Soil Sci. Soc. Amer. Proc. 38:103-107.
Stanier, R. Y., N. J. Palleroni, and M. Doudoroff. 1966. The Aerobic
Pseudomonads: A Taxonomic Study. J. Gen. Microbiol. 43:159-271.
Stewart, D. E. 1974. The Regulation of On-site Home Sewerage in Wisconsin:
A Study as it Exists Today, An Analysis of its Effectiveness and Proped
Changes, Small Scale Waste Management Project, University of Wisconsin,
Madison.
Stewart, D. E. 1976. Regulatory Methods to Assure the Maintenance of
On-site Sewerage Systems. Presented at 1976 Annual Meeting
Amer. Soc. Agr. Engr. Lincoln, Nebraska.
-113-
-------
Stewartj D. E. 1977. Alternative Methods of Regulating Onsite Domestic
Sewerage Systems. In: Individual Onsite Wastewater Systems.
N. I. McClelland (ed.). Ann Arbor Science, Ann Arbor, Michigan.
pp. 53-66.
Stonehill, A. A., S. Krop and P. M. Borick. 1963. Buffered Glutaraldehyde -
A New Chemical Sterilizing Solution. Amer. J. Hosp. Pharm. , 20:4-58.
Stothoff, J. R. 1976. The Effect of Applied Wastewater, Loading Rate and
Sand Size On the Performance of Intermittent Sand Filters.
M.S. Independent study, University of Wisconsin, Madison, Wisconsin.
Struther, P. H. and D. H. Sieling. 1950. Effect of Organic Anions on
Phosphate Precipitation by Iron and Aluminum as Influenced by pH.
Soil Sci. 69:205-213.
Suess, A. 1974-. Experimental Irradiation for the Sterilization of Sewage
Sludge. Kerntechnik (Ger.) 16:65.
Tamblyn, T. A. and B. T. Sword. 1969. The Anaerobic Filter for the
Denitrification of Agricultural Subsurface Drainage. Proc. 24-th Ind.
Waste Conf., Lafayette, Indiana, pp. 1135-1150.
Tannenbaum, S. R. 1976. Nitrates, Nitrites and N-Nitroso Compounds as
Environmental Hazards: A Personal Perspective. Amer. Can. Soc. Science
Writers Seminar, Mar. 26, 1976 (Mimeo).
Tanimoto, R. M., N. C. Burbank, Jr., R. H. F. Young, and L. S. Lau. 1968.
Migration of Bacteriophage T4- in Percolating Water Through Selected
Oahu Soils. Water Resources Research Center Technical Report No. 20.
Univ. Hawaii, Honolulu.
Tate, R. L. Ill, and M. Alexander. 1976. Resistence of Nitrosamines to
Microbial Attack. J. Environ. Qual. 5:131-133.
Taylor, B. F., D. S. Hoare and S. L. Hoare. 1971. Thiobacillus Denitrifica-
tion as an Obligate Chemolithotroph. Isolation and Growth Studies.
Arch. Mikrobiol. 78:193-204.
Ten States Standards. 1960. Recommended Standards for Sewage Works. Great
Lakes - Upper Mississippi. Board of State Sanitary Engineers. Health
Education Service. P.O. Box 7283, Albany, NY.
Thomas, R. E. and T. W. Bendixen. 1969. Degradation of Wastewater
Organics in Soil. JWPCF 4-1(5): 808.
Thomas, R. E., W. A. Schwartz and T. W. Bendixen. 1966. Soil Chemical
Changes and Infiltration Rate Reduction Under Sewage Spreading.
Soil Sci. Soc. of Amer. Proc. 30:641-64-6.
-114-
-------
Tipton, D. W. 1975. Experience of a County Health Department With
Individual Aerobic Sewage Treatment Systems. Jefferson County Health
Department, Lakewood, Colorado.
Truesdale, C. A. and H. T. Mann. 1968. Synthetic Detergents and Septic
Tanks. The Surveyor 131 (3953).-28.
U.S. Environmental Protection Agency. 1973. Manual of Individual Water
Supply Systems. EPA-430-9-73-003.
U.S. Environmental Protection Agency. 1975. Manual for Nitrogen Control.
U.S. Public Health Service. 1967. Manual of Septic Tank Practice.
Publication No. 526, U.S. Department of Health, Education and Welfare,
Public Health Service, Washington, B.C.
Unluturk, A. 1974. Aerobic Decomposition of Anaerobically Digested Sewage
Sludge in Soil. M.S. Thesis. Department of Soil Science, University
of Wisconsin, Madison, Wisconsin.
Vander Velde, T. L. 1973. Poliovirus in a Water Supply. J. Am. Water
Works Assoc. 65:345-346.
Van Donsel, D. J., E. E. Geldreich, and N. A. Clarke. 1967. Seasonal
Variation in Survival of Indicator Bacteria in Soil and Their
Contribution to Stormwater Pollution. Appl. Microbiol. 15:1362-1370.
Veneman, P. L. M., M. J. Vepraskas, and J. Bouma. 1976. The Physical
Significance of s Mottling in a Wisconsin Toposequence.
Geoderma 15:103-118.
Vepraskas, M. J. and J. Bouma. 1976. Model Experimen-ts on Mottle
Formation Simulating Field Conditions. Geoderma 15:217-230.
Vepraskas, M. J., F. G. Baker, and J. Bouma. 1974. Soil Mottling and
Drainage in a Mollic Hapludalf as Related to Suitability for Septic
Tank Construction. Soil Sci. Soc. Amer. Proc. 38:497-501.
Viraraghavan, T., and R. G. Warnock. 1973. Treatment Through Soil of Septic
Tank Effluent. Proceedings of the International Conference on Land for
Waste Management, Ottawa, Canada.
Viraraghaven, T., and R. G. Warnock. 1974. Treatment Through Soil of Septic
Tank Effluent. Proc. of the International Conference on Land for Waste
Management. Ottawa, Canada (1973), pp. 214-223.
Vishniac, W. V. 1974. Thiobacillus, p. 458-461. In: R. E. Buchanan and
N. E. Gibbons (ed.) Bergey's Manual of Determinative Bacteriology.
8th Edition. The Williams and Williams Co., Baltimore, Maryland.
-115-
-------
Voell, A. T. and R. A. Vance. 1974. Home Aerobic Wastewater Treatment Systems
Experience in a Rural County, Ohio Home Sewage Disposal Conference, Ohio
State University, Columbus, Ohio.
Waldorf, L. E. 1977. The Boyd County Demonstration Project. In: Individual
Onsite Wastewater Systems, N. I. McClelland, (ed.), Ann Arbor Science,
Ann Arbor, Michigan.
Walker, W. G., J. Bouma, D. R. Keeney, and F. R. Magdoff. 1973a. Nitrogen
Transformations During Subsurface Disposal of Septic Tank Effluent in
Sands. I. Soil Transformations. J. Environ. Qual. 2:475-4-80.
Walker, W. G., J. Bouma, D. R. Keeney, and P. G. Olcott. 1973b. Nitrogen
Transformations During Subsurface Disposal of Septic Tank Effluent in
Sands. II. Ground Water Quality. J. Environ. Qual. 2:521-525.
Washington Suburban Sanitary Commission. 1968. WSSC, Hyattsville, Maryland,
Commercial Flow Study, Interoffice memo dated December 18, 1968.
Water Pollution Control Federation. 1970. Manual of Practice No. 9. Design
and Construction of Sanitary and Storm Sewers. Water Pollution Control
Federation, Washington, D.C.
Water Resources Management Workshop. 1973. Groundwater Quality: Door
County, Wisconsin. Institute for Environmental Studies., Report 7,
University of Wisconsin, Madison, Wisconsin.
Weber, W. J., Jr. 1972. Ion Exchange in Physicochemical Processes for
Water Quality Control, W. J. Weber, Jr., Wiley Interscience, New York,
p. 261.
Weibel, S. R. 1950a. Brine Waste Effects on Septic Tanks and Soil Absorption
Systems. Presented at Conference on Water Softening. Purdue University.
Weibel, S. R. 1950b. Ground Garbage and Household Septic Tanks Systems.
Presented at Refresher Course, Annual Meeting Amer. Soc. Agric. Engr.
San Antonio, Texas.
Weibel, S. R. 1955. Septic Tanks: Studies and Performance. Agricultural
Engineering 35:188-191.
Weibel, S. R. , T. W. Bendixen, and J. B. Coulter. 1954. Studies on Household
Sewage Disposal Systems. Part III. Department of Health, Education
and Welfare. Public Health Service, Robert A. Taft Sanitary Engineering
Center, Cincinnati, Ohio.
Weibel, S. R., C. P. Straub, and J. R. Thoman. 1949. Studies on Household
Sewage Disposal Systems. Part I. Federal Security Agency, Public
Health Service, Robert A. Taft Sanitary Engineering Center, Cincinnati,
Ohio.
-116-
-------
Wellings, F. M., A. L. Lewis, and C. W. Mountain. 1974. Virus Survival
Following Wastewater Spray Irrigation of Sandy Soils, p. 253-260.
In: J. F. Malina, Jr. and B. P. Sagic (ed.), Virus Suruvival in
Water and Wastewater Systems. Water Resources Symp. No. 7. Univ. of
Texas, Austin.
Wellings, F. M., A. L. Lewis, C. W. Mountain, and L. V. Pierce. 1975.
Demonstration of Virus in Groundwater After Effluent Discharge Onto
Soil. Appl. Microbiol. 29:751-757.
Wenk, V. D. 1971. Water Pollution: Domestic Wastes. A Technology Assess-
ment Methodology, Vol. 6, Pub. No. PB 202778-06, prepared for the Office
of Science and Technology, Executive Office of the President, Washington,
D.C.
Winneberger, J. T. 1976. The Principle of Alternation of Subsurface
Wastewater Disposal Fields. On-Site Waste Management, Vol. V,
Hancor, Inc., Findlay, Ohio.
Winneberger, J. T. and J. W. Klock. 1973. Current and Recommended Practices
for Subsurface Wastewater Disposal Systems in Arizona. Engineering
Research Center, College of Engineering Sciences, Arizona State University,
Tempe, Arizona.
Winneberger, J. T. and W. H. Anderman, Jr. 1972. Public Management of Septic-
Tank Systems is a Practical Method of Maintenance. J. Environ. Health
35:145-146.
Winneberger, J. H. and P. H. McGauhey. 1965. A Study of Methods of
Preventing Failure of Septic Tank Percolation Fields - Fourth Annual
Report. SERL Report No. 65-16. Sanitary Engineering Laboratory,
University of California, Berkeley, California.
Winneberger, J. H., L. Francis, S. A. Klein and P. H. McGauhey. 1960.
Biological Aspects of Failure of Septic-Tank Percolation Systems.
Final Report. Sanitary Engineering Research Laboratory, University
of California, Berkeley, California.
Winneberger, J. H., A. B. Menar and P. H. McGauhey. 1961. A Study of Methods
of Preventing Failure of Septic Tank Percolation Fields - First Annual
Report. Sanitary Engineering Research Laboratory, University of California,
Berkeley, California.
Winneberger, J. H., W. I. Saad and P. H. McGauhey. 1962. A Study of Methods
of Preventing Failure of Septic Tank Percolation Fields - Second Annual
Report. Sanitar3' Engineering Research Laboratory, University of California,
Berkeley, California.
-117-
-------
Winston, M. A. 1975. Regulation Acts Compiled. J. Environ. Health 36:117.
Wirth, H. E. and R. C. Hill. 1967. Summary Report of a Survey of Private
Sewage Disposal Systems Serving Water Front Properties. Wisconsin
Department of Health and Social Services, Madison, Wisconsin.
Wisconsin Division of Health. 1967. Wisconsin Administrative Code H62.20.
Wisnieski, K. S. and M. Garber. 1953. Per Capita Use of Water in Public
Schools, Public Works, 84(7):97.
Witt, D. 1974a. Water Use in Rural Homes. Independent Study Report.
Presented to the University of Wisconsin, in partial fulfillment of
the requirements of the Department of Civil and Environmental Engineering
for the degree of Master of Science.
Witt, M. D. 1974b. Water Use in Rural Homes. Small Scale Waste Management
Project Publication, 1 Agriculture Hall, University of Wisconsin,
Madison, Wisconsin.
Witt, M., R. Siegrist and W. C. Boyle. 1975. Rural Household Wastewater
Characterization. Proc. National Home Sewage Disposal Symposium,
Amer. Soc. Agr. Eng. pp. 79-88.
Witz, R. L., G. L. Pratt, S. Vogel and C. W. Moilanen. 1974. Waste Disposal
Systems for Rural Homes. Cooperative Extension Service, Circular No.
AE 43, North Dakota State University, Fargo, North Dakota.
Wolff, J., F. P. Linaweaver and J. C. Geyer. 1966. Commercial Water Use.
Department of Environmental Engineering Science, John Hopkins University.
Woodward, F. L. 1961. Ground Water Contamination in the Minneapolis and
St. Paul Suburbs. In: Ground Water Contamination. R. A. Taft Sanit.
Engr. Cent. Tech. Report W61-5, *pp. 66-71.
Young, R. H. F. and N. C. Burbank, Jr. 1973. Virus Removal in Hawaiian
Soils. J. Am. Water Works Assoc. 65:598-604.
Young, J. C. and P. L. McCarty. 1969. The Anaerobic Filter for Waste
Treatment. Jour. Water Pollution Control Federation, 41(5, Part 2):
R160.
Ziebell, W. A. 1975. Removal of Fecal Bacteria from Wastewater of Individual
Homes During Treatment by Conventional and Experimental Methods. M.S.
Thesis, Department Civil and Environ. Engr. University of Wisconsin,
Madison, Wisconsin.
Ziebell, W. A., J. L. Anderson, J. Bouma, and E. McCoy. 1975a. Fecal
Bacteria: Removal from Sewage by Soils. Presented at Winter Meetings
of ASAE. Chicago, Illinois.
-118-
-------
Ziebell, W. A., D, H. Nero, J. F. Deininger, and E. McCoy. 1975b. Use of
Bacteria in Assessing Waste Treatment and Soil Disposal Systems.
In: Home Sewage Disposal, ASAE publ. PROC-175, St. Joseph, Michigan.
Ziebell, W. A., R. J. Otis, and J. Bouma. 1973. An Evaluation of Two
Experimental Household Wastewater Treatment and Disposal Systems
in Southeastern Wisconsin. Small Scale Waste Management Project,
University of Wisconsin, Madison.
-119-
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APPENDIX A
WASTEWATER CHARACTERISTICS AND TREATMENT
PART 1
THE CHARACTERIZATION OF SMALL WASTE FLOWS
INTRODUCTION
The characteristics of waste flows from residential dwellings, as well
as non-residential establishments can have a profound effect on the perfor-
mance of individual treatment and final disposal methods. Various water-use
events within a dwelling or establishment create an intermittent flow of
wastewater which can vary widely in strength and volume. Quantitative and
qualitative characterization information is necessary: (l) to provide for the
effective design of treatment and disposal systems, (2) to facilitate the
development of methods to beneficially alter the typical waste characteristics,
and (3) to facilitate the development of methods to recycle resources in a
beneficial manner. To enhance the existing characterization data base, a
major study was conducted.
This characterization study was accomplished in several phases. The
first phase included the characterization of rural household wastewater. A
major effort was expended in this phase since it was felt to be of prime im-
portance. Three objectives were established for this effort: (l) identify
the contributions made to the wastewater stream by various individual water-
using events within the home, (2) identify the patterns in water usage and
hence wastewater production on an hourly, daily and seasonal basis, and
(3) identify the qualitative characteristics of the wastewater resulting from
the various water-use events.
An attempt was made to obtain a sufficient number of sites to yield a
variety of family sizes and types. At each study home, efforts were made to
monitor water use and/or wastewater production for a sufficient length of
time to provide representative, useful characterization information. Water
use (wastewater production) was monitored at eleven homes for a total of ^3^
days. Chemical/physical wastewater characteristics were identified through
monitoring at four households for a total of 35 days. The microbiological
characteristics of selected household event wastewaters were determined
through in-house sampling at each of six households.
The second phase of this study involved the characterization of waste-
waters produced by various commercial establishments. A major objective of
this phase of the study was to compile a comprehensive summary of the existing
characterization data which heretofore had been scattered in bits and pieces
amidst the literature and in other dark places. A second objective was to
consider and evaluate various methodologies used for estimating water use/
A-l
-------
wastewater production at facilities serving a transient population. Finally,
the existing characterization data "base was to be expanded where necessary and
feasible.
The final phase of this study involved an investigation of methods for
in-house alteration of the typical characteristics of small wastewater flows,
primarily those from households. Although it was not among the major objec-
tives of this study to actively evaluate methods of in-house alteration,
since the results of the characterization phases identified areas offering
potential for wastewater alteration, an investigation and discussion of this
topic was deemed necessary.
CHARACTERISTICS OF HOUSEHOLD WASTEWATER
The first phase of the characterization effort involved the quantitative
and qualitative characterization of rural household wastewater. The available
characterization information was reviewed, compiled and summarized prior to
conducting field studies.
Review of the Existing Literature
A limited number of investigations have been conducted to delineate the
characteristics of the water usage and wastewater production of individual
household water-using events and activities. A brief discussion of these
investigations follows. In 1968, Olsson, Karlgren and Tullander (1968) re-
ported the results of a study investigating the quantities and types of
pollutants in several fractions of domestic wastewater. The investigation was
conducted at a building containing 25 apartments situated in a suburb of
Stockholm, Sweden. The drainage system for the building was installed so that
wastewater could be obtained separately from each of the following groups:
10 kitchens, 10 bathrooms (excluding toilet wastes), 15 kitchens and bathrooms
combined (excluding toilet wastes), a laundry and 28 vacuum toilets. The
wastewater flow volumes were measured and samples of each group were analyzed
for a variety of parameters during a 12-week period (January 11 to April k,
1965).
The waste flow volumes were measured continuously throughout the study
for each category of wastewater. The samples used for qualitative analyses
were either random grab or flow composited samples on a daily or weekly basis,
depending on the parameter of interest and the category of wastewater. Basi-
cally, BOD- analyses were performed on daily composites; the pH, temperature
and specific conductance were measured continuously; and the remaining
chemical/physical parameters were based on weekly composites. In addition,
during week 3 the daily variations for all parameters were studied. Through-
out the study, however, samples of the toilet and laundry waste were taken
randomly during each week. Bacteriological analyses were conducted on the
wastewater from kitchens and bathrooms during week 3 for total bacteria,
total coliform and fecal coliforms. During week 12 similar analyses were
performed on the wastewater from the combination kitchen-bathroom group and
the toilet wastes.
A-2
-------
To express the results in terms of mass/capita/day, interviews were con-
ducted with the occupants of each apartment to determine the total number,
occupation, sex, age and habits of -the residents. One interview was held
immediately before the study and a second immediately after. A summary of
selected mean results determined in the study is shown in Table A-l.
TABLE A-l. SELECTED CHARACTERISTICS OF VARIOUS COMPONENTS OF
RESIDENTIAL WASTEWATER (Olsson, Karlgren and
Tullander, 1968)
Kitchens
Parameter
BOD,-, g/cap/day
Total P,
g/cap/day
PO^-P, g/cap/day
Kjeldahl N,
g/cap/day
NH^-N, g/cap/day
N02-N, g/cap/day
TS, g/cap/day
TVS, g/cap/day
TSS, g/cap/day
TVSS, g/cap/day
PH
Temp, °C
Plate Count-35°C,
Log no . /cap /day
Coli - 35 °C,
Log no. /cap /day
Coli - kk°C,
Log no . /cap/day
Flow, L /cap /day
Week
1-12 3
17
0.3
0.01
0.6
o.oi*
0.001
36
27
13
12
7.3
28
_
_.
_
51
-
0.3
0.01
0.6
o.ok
0.001
31
23
11
10
7.2
28
10.55
10.08
9.36
hU
Bathrooms
Week
1-12 3
5
0.6
0.01
0.3
0.03
0.001
22
10
3
2
8.1
25
_
_
.
62
h
0.6
0.01
0.3
0.011
0.001
19
9
3
2
7.8
25
10.61
9.0
8.30
55
Combined
Kitchens & Vacuum
Bathrooms Laundry Toilet
Week
3
20
0.9
0.02
0.9
0.051
0.002
50
32
111
12
-
26
_
_
_
99
Week Week
1-12 1-12
3 20
1.3 1.6
-
0.2 11
-
-
19 53
7 39
2 30
1 25
9.8 8.9
-
10.79
9.68
9-58
8.5 8.5
A-3
-------
As part of a study to evaluate the feasibility of various household waste-
flow reduction techniques, information was obtained on residential water use/
wastewater flow volumes by Cohen and Wallman (197*0. Eight families were in-
cluded in the study, six in southeastern Connecticut and two in San Diego,
California. At each of the homes, water meters were installed on the house
supply line and the individual lines to the toilet and bath/shower. At five
of the homes the supply line to the laundry was metered also. Water use was
recorded weekly by the homeowners over two, six-month periods, before and
after waste-flow reduction devices were employed. The results of this moni-
toring are summarized in Table A-2.
TABLE A-2. HOUSEHOLD WATER USE - L/cap/day
(Cohen and Wallman, 197*0
Home
1
2
3
1*
5
6
7
8
Average
% of Inlet
Inlet
1U5
381*
157
220
263
190
ll*3
179
210
-
Toilet
3l*. 1*
10U
1*1.0
72.5
113
UU. 8
1*2.1
69.8
65.1
30.6
Bath/
Shower
lU.O
36.0
10.8
16.6
JlO.2
28. 1*
2U.9
20.8
23.8
11.6
Kitchen &
Laundry Bathroom
69.0
3H. 8
-
-
-
37.8
31.U
26.5
39.8 68.3
19.1 29.1*
Hot and cold water use by the bath and laundry were also recorded as part of
this study. The average ratio of hot to cold water use was calculated to
equal approximately 1.2 for the bath and 0.8 for the laundry.
A third characterization study was performed by Laak (1975) in 1972 at
the University of Connecticut involving five families. The first phase of the
study identified the volume of wastewater generated by various water-using
events. For the kitchen sink, bathroom sink and bathtub, relationships be-
tween depth and volume were obtained at each home. Measurements of the
liquid depth before draining the wastewater from each of these fixtures were
recorded by the user. For clothes washing, the average quantities of water
used for each machine setting were used to estimate wastewater production.
For toilet flushing, the volume of water used per flush was calculated from
the flush tank dimensions. The number of flushes per day were recorded by
counters activated by the flush lever which enabled the volume of water used
per capita per day to be calculated. The results of this characterization
are given in Table A-3.
A-l*
-------
TABLE A-3. MEAN WATER CONSUMPTION BY HOUSEHOLD
EVENTS - L/cap/day (Laak, 1975)
Home
A
B
C
D
E
Weighted
Average
Kitchen
Sink
12.1
3k. k
12.9
7-9
7.9
13.6
Bath
58.2
20.0
22.3
18.9
37.8
32.1
Bathroom
Sink
11.3
12.1
5-7
3.8
10.2
7.9
Laundry
54
7-9
16.3
29-9
17.0
28.0
Toilet
112
138
42.3
51.8
49.9
74.8
Total
247
212
99
112
123
156
The second phase of this study involved identifying the quality of the
wastewater generated from the plumbing fixtures. At each of the five resi-
dences, the wastewater was sampled immediately after dishwashing, "bathing,
laundering, hand or face washing and tooth brushing. Analyses were conducted
for a variety of chemical/physical parameters. The pollutant concentrations
determined were converted to mass/capita/day values by utilizing the mean flow
results shown in Table A-3. The wastewater from toilets was not sampled.
Instead, fresh feces from two persons and urine from student washrooms were
collected on 12 separate occasions. These washroom samples were prepared for
analysis by dissolving 0.1 gram of wet feces or 1 milliliter of urine in one
liter of distilled water. The average discharge of urine was estimated at
1200 mL/day per adult and 800 mL/day per child; wet fecal output was estimated
at 130 gram/day per adult and 90 gram/day per child. The weighted mean pro-
duction rates for the 10 adults and 6 children of this study were calculated
to be 115 gram feces/day and 1050 mL urine/day. Using these production rates
and the results of the sample analyses, the average fecal and urine contribu-
tions in toilet wastewater were calculated. The individual event pollutant
contributions determined in this study are summarized in Table A-4.
Laak also investigated the pollutant load contributed by the manufactured
materials or consumer products used at each plumbing fixture. To accomplish
this, the brands of materials used in each family were independently purchased
and analyzed.
In 1974, the results of a study to determine the character of individual
household wastewaters were reported by Ligman, Hutzler and Boyle (197*0. The
first phase of the study involved a wastewater generation survey to determine
the number of uses per person per day for each of five household events:
toilet, bath/shower, laundry, dishwashing and garbage disposal use. Question-
naires were completed by the residents of 20 rural homes, four urban homes and
six apartment households. The residents recorded the daily number of occur-
rences for the five household events over a one-week period. The results of
the survey for rural homes are shown in Table A-5. Urban event occurrences
A-5
-------
TABLE A-U. AVERAGE POLLUTANT CONTRIBUTIONS FROM INDIVIDUAL
HOUSEHOLD EVENTS - grams/cap/day (Laak, 1975)
Parameter
BODc
COD
Total Kjeldahl
Nitrogen
NH3-N
NO -N
POU-P
Kitchen
Sink
9.20
18.80
*
0.07^
0.0076
0.173
Bathing
6.18
9.08
-
O.OU3
0.0116
0.030
Bathroom
Sink
1.86
3.25
-
0.009
0 . 0022
0.386
Clothes
Washing
7.90
20.30
-
0.316
0.0353
U.79
Toilet
23. 5^
67.78
-
2.78
0.016
6.1*7
Total
1*8.69
119. ^
-
3.22
.0727
11.86
* Samples from Homes A, B, and E were analyzed, yielding a range of values
equal to 0.05** to 0.1*10 grams/cap/day.
TABLE A-5. EVENT USAGE SURVEY RESULTS AT
RURAL HOMES (Ligman, Hutzler
and Boyle, 197*0
Statistic
Toilet Clothes
Use Bathing Washing
uses/cap/day
Manual Automatic Garbage
Dishwashing Dishwashing Disposal
uses/home/day
Mean
Responses
Range
95$
Confidence
Interval
3.6 0.1*1* 0.3l*
62 33 27
1.5-7-2 O.lU-1.03 0.07-0.57
3.0-U.5 0.36-0.53 0.26-0.1*1
1.9 1.3 2.9
26 9 7
0.5-3.7 O.U-2.5 1.1-5.0
1.6-2.3 0.9-1.8 1.7-3.6
did not differ significantly from those shown for rural homes. To estimate
water use/wastewater production, the survey responses (number/capita/day)
were multiplied by typical water use values given in the literature (volume/
occurrence). The results calculated have been summarized in Table A-6.
The second phase of this study involved sampling bath, shower, dish-
washing and laundry wastewaters at each of ten rural households and five
apartment households (January to May of 1972). Three samples of each event
were taken by the occupants of each home. If a family use'd an automatic dish-
washer, they thoroughly rinsed the dishes before inserting them into the dish-
washer, sampled the rinse water and noted its volume. For automatic clothes-
washers samples were only taken from the first discharge from the machine.
A-6
-------
TABLE A-6. CALCULATED RURAL WASTEWATER FLOW VOLUMES* -
L/cap/day (Ligman, Hutzler and Boyle, 197*0
Day of Week Mean Range 95% Confidence Interval
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
187
170
iMi
167
153
190
165
76 -
73 -
73 -
57 -
55.6 -
60.5 -
31 -
1*15
363
239
398
1*65
6ih
3k6
Iho
130
119
129
118
128
122
- 235
- 209
- 167
- 201;
- 287
- 252
- 208
Average l68 31 - 6lU 153 - 183
* Based on the recorded occurrences per capita per day and the following
waste flow volumes: Toilet - 18.9 L/use (5 gal/use)
Bath/Shower - 9^.5 L/use (25 gal/use)
Clotheswasher - 189 L/use (50 gal/use)
Dishwashing - 26.5 L/use (7 gal/use)
Garbage Disposal - 7.6 L/use (2 gal/use)
The average pollutant concentrations for the wastewater from the entire
Clotheswasher cycle were estimated to be 58$ of the concentration in the first
discharge. For the bath, shower and dishwashing wastewaters, the occupants
were asked to estimate the volume of wastewater from which they obtained each
sample, while Clotheswasher discharges were assigned an arbitrary value of
151 L (UO gal). The estimated wastewater volumes were combined with the
measured concentrations to determine mass loadings per event (Table A-7)•
In addition to the above studies, an extensive literature review was
conducted. Based on the results of both, the mean characteristics of individ-
ual household wastewaters were estimated as shown in Tables A-8 and A-9.
In 1975, Bennett and Linstedt (1975) reported the results of a study con-
ducted by the University of Colorado to determine the characteristics of
household wastewater and evaluate the effect of these characteristics on
various types of treatment processes. The wastewater characterization phase
involved water-use monitoring and wastewater sampling of the following house-
hold events: sink use, toilet flushing, garbage grinding, bathing, clothes-
washing, and dishwashing.
Water-use monitoring was conducted at each of five homes in the Boulder,
Colorado area for a one- to two-week period. A recording device was attached
to the water meter at each study home which provided a record of water use
versus time of day. To identify which household water-use event generated
each recorded volume, the residents noted the type of event, time of occur-
A-7
-------
TABLE A-T. SELECTED CHARACTERISTICS OF INDIVIDUAL EVENT WASTEWATER -
grams/event (Ligman, Hutzler and Boyle, 197*0
Parameter
Clothes Washing
Bathing
Dishwashing
BODC
Total Solids
Total Suspended Solids
Total Volatile Solids
Total Volatile
Suspended Solids
38.6*
U.5 - 112
160
53.1 - 335
29.5
O.U5 - 79.^
57.7
30.0 - 96.2
16.3
17.7
10.0 - 28.6
1+2.2
22.2 - 72.6
11.1+
1.8 - 37.7
15.0
7.3 - 25.9
2.3
0.1+5 - 7.7
11.8
1.8 - 27.2
20.0
6.8 - 1+5.^
5.9
0.90 - 16.8
1U.5
3.2 - 38.1
5.0
0.1+5 - 13.6
Number of Samples
8-21+
8-13
23 - 33
* Mean over range
TABLE A-8.
INDIVIDUAL EVENT WASTEWATER QUALITY SUMMARY -
grams/event (Ligman, Hutzler and Boyle, 197*0
Parameter
Clothes
Washing
Bathing Dishwashing
Garbage
Disposal
BODC
Total Solids
Suspended Solids
Pats
Total Nitrogen
38.6*
1+.5 - 112
160
53.1 - 335
29.5
0.1+5 - 79.1
17.7
10.0 - 28.6
1+2.2
22.2 - 72.6
11.1+
1.82 - 37-7
11.8
1.82 - 27.2
20.0
6.8 - U5.U
5.9
0.91 - 16.8
t
1+1.3
33.1 - 1+9-5
81.7
75.k - 90.8
58.1
1+9.9 - 66.7
10.U
5.9 - 15.0
1.2
Total Phosphorus
Flow, Liters
9.1
3.6 - 12.7
151
128 - 223
-
9^.5
37-8 - 113
1.36
Trace - 2.72
_
18.9 - 60.5
-
5.7
3.8 - 7.6
* Mean value over range of values
Values not identified
A-i
-------
TABLE A-9. INDIVIDUAL EVENT POLLUTANT CONTRIBUTIONS SUMMARY -
gram/cap/day (Ligman, Hutzler and Boyle, 1971*)
Parameter
Clothes
Washing
Bathing
Dishvashing
Garbage
Disposal
Toilet
BODS 9-5* 9.1 5.9 30.9 23.6
? 1.1* - 28.1 5.0 - lit.5 0.1*5 - 6.81 25.0 - 37.2 17.3 - 37.7
Total 1*0.0 20.9 10.0 6l.3 97.2
Solids 13.2 - 81*.0 11.4 - 36.3 1.8 - ll.l* 56.8 - 68.1 82.6 - 125.3
Suspended 7.26 5.1*5 2.72 1*3.6 30.9
Solids 0.1*5 - 20.0 0.91 - 19.1 0.1*5 - 1*.09 37-7 - 1*9-9 22.7 - 1*6.3
Fats
Total
Nitrogen
Total 2.27
Phosphorus 0.91 - 3.18
t
0.1*5
Trace - 0.91
7.72 1*.5^
l*.5l* - 11.1* 0>91 _ 8.17
0.91 16.8
1.36 - 22.7
1.36
1.36 - 3.63
* Mean value over range of values
Values not identified
rence and user age group on data sheets provided. The results obtained from
this monitoring are summarized in Tables A-10 and A-11.
TABLE A-10. INDIVIDUAL EVENT WATER USE
(Bennett and Linstedt, 1975)
Event
Toilet
Bathroom Sink
Bathing
Kitchen Sink
Garbage Disposal
Automatic Dishwasher
Clothe swasher
L/use
15.5
7.6
103
3.8
7.9
26.5
1*3.8
uses /cap/day
3.6
2.5
0.32
2.60
0.1*0
0.15
0.30
L/C ap /day
55-6
19.0
32.9
9.8
3.0
1*.2
1*3.8
Total
168
A-9
-------
TABLE A-ll. RESIDENTIAL WATER USE - L/cap/day
(After Bennett and Linstedt, 1975)
Home
1
2
3
k
5
Sink
36.1
IT A
^5.7
76.7
17. U
Toilet
68.7
38.8
89-9
I08.lt
37.8
Garbage
Disposal
2.U
O.U
U.O
16.3
1.7
Bathing
13.1
31.8
61.7
29.6
1+0.9
Clothes-
washer
55. U
26.8
20.9
59.8
3^.3
Dish-
washer
U.6
1.3
7-3
-
3.7
The flow data was also analyzed to provide hourly water use patterns.
illustrate the daily variations, water use versus time of day curves were
drawn. The summary curve for all five sites is shown in Figure A-l.
To
GARBAGE
DISPOSAL
WASHING
MACHINE
M2468ION2468IOM
TIME OF DAY
Figure A-l. Daily water-use patterns
(Bennett and Linstedt, 1975).
A-10
-------
The second phase of the study determined the qualitative characteristics
of the wastewaters produced by each of the six household events studied in the
water-use phase. Grab samples were obtained from the wastewater produced by
each event (excluding the toilet) at each of the original five homes, plus two
additional homes. Individual samples of feces, urine, and toilet paper were
analyzed and the average strength of the toilet wastes was estimated. Utili-
zing the mean flow results determined in the water-use monitoring phase, the
pollutant concentrations were converted to mass/capita/day values as shown in
Table A-12.
To determine the variation in pollutant contribution throughout the day,
the hourly water-use curve (Figure A-l) was combined with the wastewater
quality data (Table A-12). Curves such as that shown in Figure A-2 for the
hourly COD profile were developed.
SHOWER
BATH
M 2 4 68ION246
TIME OF DAY
8 10 M
Figure A-2.
Hourly COD profile
(Bennett and Linstedt,
1975).
As part of this investigation, the pollutant contributions of several
cleaning products commonly used in the home were also identified.
A-11
-------
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A-12
-------
Data Generation Methods
Field studies to further delineate household waste-water characteristics
were accomplished in three phases: (l) water use characterization (waste-
water production), (2) wastewater quality characterization for chemical/
physical parameters, and (3) wastewater quality characterization for micro-
biological parameters. A discussion of the methods used for each of these
phases follows. It should be noted that certain of the information presented
has been discussed previously (Siegrist, 1975; Siegrist, Witt and Boyle, 1976;
Witt, 197^a; Witt,
Water Use Characterization —
Eleven rural homes were monitored offering a variety of family types and
sizes as described in Table A-13. Five water-use events were included: toilet
usage, bathing, clotheswashing, dishwashing and water softening.
TABLE A-13. FAMILY INFORMATION - WATER USE MONITORING PHASE
Family
Unit
A
B
C
D
E
F
G
H
I
J
K
Children
Adults (Age)
2
2
2
2
2
2
2
3
2
2
2
2
1
2
k
I
3
5
0
3
5
2
(8,18)
(15)
(3,5)
(10,12,
17,19)
(9 mo.)
(6,8,9)
17,18) '
(2,3,5)
(3,7,11,
16,17)
(8,15)
Bathrooms
2 1/2
1 1/2
1
2
2
1 1/2
1 1/2
1
1 1/2
1 1/2
2
Automatic
Clothes
Washer
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Automatic
Dish
Washer
Yes
Yes
No
Yes
Yes
No
No
No
Yes
No
No
Occupation
Water of Head of
Softener Household
Yes
No
Yes
Yes
No
No
Yes
Yes
No
No
Yes
Herdsman
Earth
Contractor
Herdsman
Resort
Employee
Pharmacist
Paper Mill
Worker
Dairy Farmer
Farm Worker
Meat Cutter
Agronomist
Agriculture
Professor
Monitoring equipment—When selecting the water-use monitoring equipment,
a prime consideration was to avoid interruption of the normal activities with-
in the study homes. As a result, a chart recorder (F.S. Brainard and Company,
New Hope, PA, Model 67 RF) driven by a household water meter was chosen (Fig-
ure A-3).
A-13
-------
RECORDER
CHART
INKWELL/PEN
CONNECTING CABLE
^AMPLITUDE
ADJUSTMENT
GEAR REDUCTION
DEVICE
TO HOUSE
^WATER
METER
FROM
PRESSURE
TANK
Figure A-3. Water use monitoring equipment.
The recorder employed a 20 cm (8 in) diameter metal disc to which calibrated
paper charts could be attached. The disc and attached chart were rotated by
an eight-day, spring-wound clock at a rate such that charts covering one-week
periods could be utilized. The recorder was connected mechanically to a water
meter located in the water supply line at the outlet of the household pressure
tank. As water was used, the pointer on the face of the water meter caused an
ink pen on the recorder to be driven back and forth across the paper chart.
The volume of water used was directly proportional to the distance the pen
moved across the chart, and the time of use was indicated by time calibrations
on the chart.
Data collection—During operation at each of the study homes, the record-
er charts were changed on a weekly basis. This eliminated much of the home-
owner's involvement and lessened the chance of altering the normal life style
of the family. To expedite data collection at the eleven homes, several chart
recorders were utilized simultaneously. The recorders were moved between the
eleven homes during the study, with efforts made to obtain four weeks or more
of data at each, in segments no smaller than seven continuous days. Further,
A-lH
-------
to allow winter to summer water-use comparison, at least five weeks of summer
data and four weeks of winter data were obtained at each of three households.
In total, data were collected for k3h days.
Data interpretation and analysis—Each recorder chart generated was ana-
lyzed to determine the type of water-using event, the time of occurrence and
the volume of water used for each of the many water-use patterns recorded. To
aid in event identification, background information on family habits and
appliances within the home was obtained using a short questionnaire. In addi-
tion, a check sheet was used during a two- to three-day period during the
initial installation of the monitoring equipment at each home. The residents
recorded the time of occurrence for each type of event three times. This
produced example chart patterns for each event. Utilizing this background
information, individual water-using events were identified on each chart by
comparing the flow pattern recorded with the characteristics of the example
events. The volume of water used by each identified event was determined by
measuring the distance the ink pen moved across the calibrated paper charts.
As a check on the chart record and interpretation, the household water
meter reading was noted at the beginning and end of each recording period.
This total water use figure was used as a check against the total volume
determined by summing up the volumes measured for the individual events.
Additional checks included the installation of counters on the toilets., con-
sultation with the homeowner regarding any extraordinary flows, and cross-
checking the data where possible with the qualitative characterization phase
of this study.
Two computer programs were developed to compile the data collected. The
first program analyzed the data by hour of the day and type of event for each
of the study homes individually and all homes combined. The percentage of
the hourly flow, the average event flow per capita per hour and the standard
deviation of the event flow were computed. This program also provided a
summary of an entire 2l|-hour day including the number of event occurrences per
capita, the average and standard deviation of the event size, the average flow
per capita, the percentage of the total daily flow and the number of times the
event was observed during the sampling period.
The second computer program processed the water-use data in a similar
manner, but by day of the week rather than hour of the day. The program com-
puted the number of event occurrences per capita, the mean and 90 percent
confidence interval for the event flow volume per capita, and the mean percent
of total daily flow.
Wastewater Quality Characterization: Chemical/Physical—
Wastewater quality studies for chemical/physical parameters were conducted
at three of the residences studied in the water use (wastewater production)
phase. Since one of the three residences was occupied by a second family
during the course of the wastewater quality study, it was treated as two resi-
dences. Thus, four families were involved in the study as described in Table
A-lU.
A-15
-------
TABLE A-lU. FAMTLY INFORMATION - WASTEWATER QUALITY PHASE
Family
Unit
C
G
I
C'
Children
Adults (Age)
2
2
2
2
2 (3,5)
5 (li,9,15,
17,18)
3 (2,3,5)
1 (1)
Bathrooms
1
1 1/2
1 1/2
1
Automatic
Clothes
Washer
Yes
Yes
Yes
Yes
Automatic
Dish
Washer
No
Yes
Yes
No
Garbage
Occupation
of Head of
Disposal Household
Yes
No
No
Yes
Herdsman
Dairy Farmer
Meat Cutter
Herdsman
The waste-waters generated through occurrence of the following water-using
events were selected for this qualitative characterization: toilet flushing,
(nonfecal and fecal), garbage grinding, kitchen sink usage, automatic dish-
washing, clotheswashing (wash and rinse cycles) and bathing.
Monitoring equipment—At the onset, considerable effort was expended in
selecting the monitoring equipment. As in the water-use monitoring phase, a
primary consideration was to minimize the homeowner's involvement in the study.
Further, the equipment selected had to provide for the collection of samples
from individual event wastewaters, many of which were very heterogeneous.
After review of commercially available products indicated the lack of a suit-
able sampler, a sampling system was designed and constructed by project
personnel (Siegrist, 1975). As shown in Figure A-l*, the sampler consisted
basically of three modules with many separable parts to facilitate a portable
system. Module 1 consisted of a polyethylene receiving tank, a grinder pump
(Model SPG-150 M made by Hydromatic Pump Company of Hayesville, Ohio) and cer-
tain ancillary equipment. The polyethylene tank was h6 cm (l8 in) in dia-
meter and 8l cm (32 in) deep. A 5 cm (2 in) diameter section of plastic pipe
connected the center of the tank bottom to the intake of the grinder pump. To
the outlet of the pump was connected a 76 cm (30 in) section of 3.2 cm (1.25
in) diameter plastic pipe terminating in a cross fitting attached to a recycle,
sample, and discharge line. The recycle line, 1.9 cm (0.75 in) diameter plas-
tic pipe, directed effluent from the grinder pump back to the receiving tank.
The sample line, 1.3 cm (0.50 in) diameter rubber tubing, connected a solenoid
valve attached to the cross with Module 3. The discharge line, 3.8 cm (1.5 in)
diameter rubber fire hose, was attached to a ball valve and enabled the con-
tents of the sampler to be discharged to the onsite disposal system. Also a
part of this module were a depth recording device with stilling wells and a
high- and low-level float switch.
Module 2 was comprised of the electrical controls for the system. A
single control box contained the timers, relays and pump controls which pro-
vided for sequencing the operation of the float switches, grinder pump, sample
and discharge valves, and the distributor system (Module 3). Two continuous
chart recorders were also part of this module. One was linked to the depth
recording device (Cole-Parmer Millivolt Recorder Model 8357-02), while the
A-l6
-------
HOME
SAMPLE
DISTRIBUTOR
ELECTRICAL
CONTROLS
SEWER '
LINE-V-—
RECEIVING
TANK
DEPTH
RECORDER
SAMPLING
PIT
FLOAT
SWITCHES
IAMPLE
TORAGE
BOXES
TO ONSITE
DISPOSAL SYSTEM
GRINDER
'PUMP
Figure A-^. Wastewater sampling system.
other was connected to a temperature probe (Cole-Parmer Temperature Minigraph
Model 8356-Ul).
Module 3 included a unique sample distributor and sample storage boxes.
A schematic of the distributor system is shown in Figure A-5 and a brief dis-
cussion follows.
The basic structure of the distributor included two 38 cm (15 in) square
plexiglas plates held horizontally rigid several cm apart. A ball-bearing was
pressed into a hole located in the center of each plate through which passed
a 0.6 cm (0.25 in) vertical rod. To the upper end of this rod was fastened a
2 L funnel, which had a 1 cm (0.375 in) diameter arm of copper tubing pro-
jecting out perpendicular to the funnel axis.
The upper plexiglass plate also contained 2k sample ports spaced equally
about a circle defined by the end of the arm attached to the funnel. The
funnel and arm were rotated from sample port to port by a simple system. Two
23 cm (9 in) diameter plexiglas plates were located between the two square
A-17
-------
I OF 24 SAMPLING
PORTS LOCATED
AROUND THE
PERIPHERY OF
THE PLEXIGLASS
VERTICAL
SUPPORT ROD
.3 CM
1GON
3ING
Y
TUI
SAMPLE.
BOTTLI
o
ATTACHMENT^!
FOR
SAMPLE
LINE
PVC
FUNNEL
AIM IRON
SUPORT
WEIGHT
DACRON
HREAD
CM
COPPER
TUBIf
0.6 CM
PLEXIGLASS
DIRECTING
BALL EYEHOOK
BEARING
o
Figure A-5. Distributor system schematic.
plates and vere rigidly fastened to the 0.6 cm vertical rod. Both of these
circular plates contained 2h, 2.5 cm (l.O in) pegs equally spaced about its
periphery. The plates as attached to the vertical rod were separated by about
5 cm (2 in) with the pegs facing toward each other and being exactly offset.
Located between the two circular plates was a bushing through which the verti-
cal rod passed freely, and to which was attached a brass rod (stepper arm)
which could be moved up and down freely. This stepper arm passed between two
adjacent pegs on the lower plate and was connected to a solenoid attached ver-
tically to the upper, 38 cm (15 in) square plexiglas plate.
A heavy thread was attached to one of the pegs on the lower plate and
directed to a weight in such a way that a rotating force would be exerted on
the vertical support rod, the circular plexiglas plates and pegs, and the
funnel and arm. When inoperative, the end of the funnel arm would be posi-
tioned directly over one of the 2U sample ports. Activating the solenoid
would raise the stepper arm into the pegs on the upper plate and allow the
funnel arm to rotate until a peg on the upper plate hit the stepper arm.
Deactivating the solenoid caused the stepper arm to drop back down into the
A-18
-------
lower pegs, allowing the funnel arm to rotate until the next lower peg hit the
stepper arm. At this point, the funnel arm was positioned above the next
sample port. In this manner, the funnel arm was rotated to each of the 2k
sample ports. Rotation past the 2l|th sample port closed a switch which dis-
connected the sample valve of module one and also prevented further rotation.
Insulated storage boxes were provided with this module to preserve the
collected samples. The distributor system was positioned on top of these
boxes and lengths of 1.3 cm (0.5 in) diameter Tygon tubing were attached to
each of the 2k distributor sample ports and directed through holes in the
boxes into one of 2k, 2L sample bottles. Each of the sample ports corres-
ponded to a certain sample bottle position so that with the ports numbered in
order of rotation of the funnel arm, the sample bottles would be numbered in
the order in which they were taken.
When installed at one of the study homes as shown in Figure A-k t the
wastewater generated was directed into the polyethylene receiving tank. When
the volume of wastewater in the tank reached 13 L (3-5 gal) or more, the high
level float switch was activated which in turn initiated a sampling cycle.
(Note: samples of water-using events producing less than 13 L were not ob-
tained.) The grinder pump was activated first, homogenizing and recycling the
contents of the receiving tank for approximately 90 sec. Then, the sample
valve was opened to permit a 1 to 2 L sample to be pumped to the distributor
system. Fifteen seconds later, the discharge valve was opened and the contents
of the receiving tank were discharged to the onsite disposal system. When the
low-level float switch was activated, the pump operation was terminated. The
remainder of the cycle included opening the sample valve briefly to gravity
drain the sample line back into the receiving tank (170 sec), the advancement
of the distributor system to the next sample port (205 sec), closing of the
discharge valve (280 sec) and resetting of the system (300 sec).
To determine whether a sample taken by this system was representative of
the wastewater flowing into the receiving tank, several mixing tests were per-
formed. The results of these tests indicated that the system did take rep-
resentative samples of the influent wastewater.
Data collection—During operation at each home, daily site visits were
made. The sample bottles were replaced, the distributor system reset, and
the unit inspected. Any samples collected were transported back to the Uni-
versity of Wisconsin for analysis. The sampling system was moved between each
of the four study homes until each had been monitored over several 3- to k-day
periods. In total, data were collected for 35 days.
Data interpretation and analysis—Each sample collected was analyzed for
various chemical/physical parameters according to the procedures listed in
Table A-15• The event that produced each collected sample was identified by
several means. The depth recording device and continuous chart recorder en-
abled the determination of the time of occurrence and volume of the event
which generated each of the collected samples. The residents of each home
cooperated during each monitoring period by completing a check sheet noting
the type of event and time of occurrence. Also helpful in identification
were visual inspections of the samples. Finally, an added aid were the flow
A-19
-------
patterns generated by the depth recorder, which were found to be characteris-
tic of each of the water-using events. Utilizing these means, the responsible
event was identified for about 50 percent of the collected samples. Of these,
approximately 80 percent were utilized. The remaining 20 percent of the
samples were generated by more than one water-using event and were therefore
not used in the analysis.
TABLE A-15. LABORATORY ANALYSIS PROCEDURES
Parameter
Test Employed
BOD,- Unfiltered
BOD5 Filtered
Two Yellow Springs Instrument Company dissolved
oxygen meters used on each sample. Meters were
standardized using Winkler method with azide
modification. For the filtered sample a What-
man #2 filter was used.
TOC Unfiltered
TOC Filtered
Total solids and
Volatile solids
Suspended solids and
Volatile Suspended Solids
Beckman Model 915 total organic carbon analyzer.
For the filtered sample a Whatman #2 filter was
used.
According to procedures outlined in Section
22UA and 22*«B of Standard Methods (1971).
According to procedures outlined in Section
lU8c of Standard Methods (1971)• Measurements
made directly using a 2.1 cm glass fiber filter
disk.
Total Nitrogen
NH3-N and N03-N
Total Phosphorus and
Ortho Phosphorus
Grease
Olson Modified Semimicro Kjeldahl procedure
(Bremner, 19&5a).
Steam distillation-titration procedure (Bremner
and Keeney, 1965).
Vanadomolybdate Yellow Color Method (Jackson,
1958).
After above samples taken off, remainder of
sample acidified with HCL and grease deter-
mined according to Soxhlet Extraction Method
as listed in Standard Methods (1971).
To compile the results of the sample analyses, a computer program was
developed. A principal function of the program was to make corrections for a
2.5 L (0.7 gal) residual left in the sampler receiving tank after each sample
was taken. Further, utilizing the results of analyses of tap water samples
obtained from each home, the program subtracted the carriage water contribu-
tions of the measured parameters. The corrected concentrations (mg/L) for
each sample were subsequently converted to mass/capita/day values by utilizing
the measured volume for the sample producing event and its frequency of occur-
rence (number/capita/day). As part of the first phase of this study, the
A-20
-------
frequency of occurrence for the "bath/showers, clotheswasher and toilet usage
were identified. The toilet event frequencies were separated into fecal and
nonfecal by using information presented by Perry (195*0- An average frequency
for garbage disposal usage, kitchen sink usage, and dishwashing were based on
information presented by Ligman, Hutzler and Boyle (197*0 along with consul-
tation with the homeowners. As a final operation on the data, the computer
program performed a statistical analysis, yielding the mean mg/cap/day, range
and standard deviation for each of the events studied.
Wastewater Quality Characterization: Microbiological—
A series of ancillary wastewater quality studies were conducted to iden-
tify the microbiological characteristics of two household events, bathing and
clothes washing. The automatic sampling system previously described was not
used to obtain samples for this characterization due to the high degree of in-
line contamination which would have been present. Instead, samples were taken
from each event by the household residents according to prescribed procedures.
Basically, a sample was taken after the occurrence of an event prior to dis-
charge of the wastewater to the sewer line. The samples were refrigerated
until they were picked up and transported back to the University of Wisconsin
laboratories for analysis (within 2k hours).
The initial sampling effort was conducted at three of the previously
described study homes (G, I, C^ listed in Table A-l*0 • Samples were obtained
from the bath/shower, clotheswasher-wash cycle, and clotheswasher-rinse cycle
and analyses were performed for total and fecal coliforms and fecal strep-
tococci. In addition, coliform and streptococcal isolates were taken for
further characterization.
Analyses for fecal and total coliform organisms were conducted using the
membrane filter technique of Standard Methods (1971) with the following varia-
tions: sterile 0.05$ peptone in distilled water was used as diluent; after
each filtration two, 20-30 mL portions of sterile diluent were used to rinse
the sample dilution bottle and filter funnel; and counts were expressed as
averages of duplicate samples or sample dilutions filtered. Fecal streptococci
were enumerated by the pour plate technique of Standard Methods (1971) or by
membrane filtration when sample volumes were 10 mLs or greater.
Coliform and streptococcal isolates were taken from plates of the above
media and placed on slants of tryptone glucose yeast extract agar. Coliform
isolates were taken, streaked on plates of Levine's Eosin Methylene blue agar
to check colonial morphology, reactions and purity; necessary re-isolations
and gram stains followed. Streptococcal isolates were handled similarly using
streak plates of m-enterococcus agar. Hydrogen peroxide (3%} was applied to
these plates to check for catalase. The media and tests used for further
characterization of coliform and streptococcal isolates are given in Tables
A-l6 and A-17, respectively.
Further sampling was conducted at three additional households (Table A-l8).
Samples were obtained from bathing and clothes washing (wash cycle only)
events utilizing similar sampling procedures, and analyses were performed for
total and fecal coliforms, fecal streptococci, Pseudononas aeruginosa and
Staphylococcus aureus.
A-21
-------
TABLE A-16. MEDIA AND TESTS - COLIFORM ISOLATE CHARACTERIZATION
Medium
Test
Lactose Broth
EC Broth
Tryptophane Broth
Buffered Glucose
Simon's Citrate Agar
Acid and gas production at 35°C at 2H, U8 and
72 hours.
Growth and gas in 2k hours at ^.50C.
Indole production (l) in 2k hours at 35°C.
Acid production in 5 days at 35°C, methyl red
indicator (M) acetylmethyl carbinol produc-
tion in 2 days at 35°C (Vi).
Use of citrate (C) as sole carbon source.
Combination tube of ornithine HpS production (H), ornithine decarboxylation
decarboxylase medium and (o) and motility (M ); test read in 2k hours.
H2S-motility medium
TABLE A-1T. MEDIA AND TESTS USED - STREPTOCOCCAL ISOLATE CHARACTERIZATION
Medium
Test
Brain Heart Infusion Broth
(BHI)
6.5$ NaCl Broth
0.1% Methylene Blue Milk
Lactose Broth
Starch Agar
Arginine Broth
Bile Exculin Agar
BHI plus tellurite (l part
tellurite in 2560 parts BHI)
Litmus Milk
Growth at 10°C and U5°C.
Salt tolerance - growth in k8 hours.
Tolerance and growth - methylene blue reaction.
Acid Production.
Starch Hydrolysis.
Arginine hydrolysis with NH^ production in
2k hours.
k% bile tolerance and osculin hydrolysis.
Tellurite tolerance.
Reactions over a iH-day period.
A-22
-------
TABLE A-18. ADDITIONAL FAMILY INFORMATION
Automatic Automatic Occupation
Family Children Clothes Dish Garbage of Head of
Unit Adults (Age) Bathrooms Washer Washer Disposal Household
L 2 2 (k mo., 1 Yes Yes No Poultry Man
7)
M
N
2
2
0
0
1
1 1/2
No
Yes
No
Yes
No
Yes
Poultry Man
Engineer
Analyses for fecal and total coliform organisms were conducted using the
5 tube MPN test procedures outlined in Standard Methods (1971) with the fol-
lowing variations: 'sterile .05% peptone in distilled water was used as a
diluent. Fecal streptococci were enumerated by the pour plate technique of
Standard Methods (1971). Analyses for Pseudomonas aeruginosa included growth
at 37°C in 5 tube MPN of asparagine enrichment broth. A blue-green fluores-
cent pigment is produced by P_. aeruginosa and inocula from the positive tubes
were transferred to slants of acetamide agar and incubated for 2k hours at
37°C. A confirmation of positives was performed at this point by preparing
streak plates on King's A agar and looking for blue-green pigment production
after incubation at 37°C for 2k hours. Staphylococcus aureus counts were
determined by a modification of Standard Methods "(1971) • The membrane filter
technique was utilized with the filtered samples pre-enriched on a tryptone
yeast broth. The medium used contained mannitol, 7-5$ sodium chloride, and
0.75 M sodium azide as selective agents. After incubation for J2 hours at
37°C, suspicious colonies were screened for DNASE production and confirmed to
be S_. aureus by the coagulase test.
A final sampling effort was conducted at home N (Table A-18) of several
wastewaters generated through hygienic care of an infant who had just received
an oral polio vaccination. In-house samples were obtained by the adult resi-
dents from the baby's stools, diajper pail, bath and laundry over a twelve-day
period. Where appropriate, each event was characterized as to quantity or
volume, contributing clothing, additives, and so forth. Analyses were con-
ducted for total and fecal coliforms, fecal streptococci, Pseudomonas
aeruginosa, and virus infectivity.
Analyses for bacteriological characteristics were conducted as described
previously. Virus infectivity was determined utilizing the following plaque
assay procedure. Approximately 10 mL of the original sample was transferred
to a test tube to which Diethyl ether (0.5 mL) was added. The test tube was
held for 1 hour at 22°C to decontaminate the sample bacteriologically (for
fecal samples, 2k hours at U°C). Sterile air was then used to bubble off the
ether. Then, 1 mL of fetal calf serum was added, the pH was adjusted to 9
using NaOH, and the prepared sample was sonicated in ice water for 5 minutes.
Using 0.5 mL of the prepared sample, log^Q serial dilutions were made. Two,
freshly confluent 25 cm flasks of Hela cell cultures were used per dilution,
with 0.5 mL of each dilution inoculated into each of two flasks. The flasks
A-23
-------
were incubated at 22°C for two hours, with rocking every 15 minutes to wet
the cells. After incubation, the inoculum was poured off, and the cell sheets
in each flask were overlaid with 5 mL of the following:
Eagle's minimum essential media, 2'x - 80%
Fetal calf serum (GIBCO) - Q%
NaHCO (5.6JC solution) - h .Q%
MgCL2 (20% solution) - k%
Gentamicin (5 mg/mL solution;
Schering) - 1.6%
Fungizone (0.5 mg/mL solution;
Squibb) -1.6%
Deionized water - q.s.
3% Noble Agar, DIFCO
(Raise the media temperature to i|2°C and lower the
Agar temperature to U2°C. Mix the two components in
the proportion of 1 part Agar to 3 parts media and
maintain at U2°C until used.)
The flasks were held until the overlay media hardened on the cell sheet and
then incubated with the cell side up for 60 hours at 37°C. After this incuba-
tion, the overlay is removed by adding about 10 mL of water to each flask and
gently floating the overlay off the cell sheet by careful agitation. After
pouring off the overlay, to each flask was added 3 mL of crystal violet stain
of the following composition:
Ethanol (95% solution) - 30 mL
Formalin (31% solution) - 25 mL
Deionized water - 3^5 mL
Crystal Violet - 2.5 gram
NaCl - H.25 gram
The stain was left on the cells for 10 minutes and then rinsed off with water.
The plaques present were then counted. The total number of plaques on four
flasks of two adjacent dilutions (e.g. 10"^ and 10~5) were divided by 1.1 and
multiplied by the reciprocal of the highest log]_g dilution to determine the
plaque forming units per mL (PFU/mL).
Results and Discussion
Water Use Characterization—
Individual event water use—The water-use data collected were analyzed
separately for each individual home and then summarized for all eleven homes
combined. For each water use event, the average water use per occurrence and
the number of occurrences per capita per day were calculated as shown in
Tables A-19 and A-20. The daily water usage resulting from each of the events
is presented in Table A-21. Inspection of these tables, readily reveals a
significant variation in water use habits between the homes studied.
The daily per capita water use values determined in this study were com-
pared with the results of previous investigators. As shown in Table A-22,
with the exception of the toilet contribution, there is fair agreement between
investigators regarding individual event water usage. The lower value for
A-2U
-------
TABLE A-19. WATER USED PER OCCURRENCE, L
Water
Toilet Laundry Bath/Shower Dishwasher Softener
Family
Unit Mean S.D.* Mean S.D. Mean S.D. Mean S.D. Mean S.D.
A
B
C
D
E
F
G
H
I
J
K
16
Ik
12
11
18
17
16
15
17
16
Ik
.6
.1+
.5
.3
.1
.0
.3
.1
.8
.6
.0
13U
1*3
137
126
158
103
108
132
105
132
11*5
7.3
6.0
10.5
1U.3
18.6
32.3
38.7
12.9
27.6
15.3
8.0
119
79
89
76
72
81+
70
62
80
81
80
62.8
38.1
53.6
39.2
1*8.6
3l*. 7
59.8
36.2
1*0.1
35.1
30.7
61*. 3
38.6
1*2.3
1*6.1
U3.8
1*8.1*
39.7
29.9
1*7-2
52.2
50.3
~
16
ll*
ll*
15
ll*
12
8
17
10
ll*
0
.2
.1*
.5
.0
.6
.0
.7
.8
.5
.7
286
_
271
360
_
_
261*
251
_
_
51*7
7.6
_
17.5
1*2.5
_
_
9.1
6.1*
_
_
238
Weighted
Average '
127 26.7
81 1*1*
1*7.2 lit. 7 307 121
In all cases, the standard deviation for toilet flush was computed to be
less than 1.5L.
TABLE A-20. FREQUENCY OF OCCURRENCE, uses/cap/day
Family Unit Toilet Laundry Bath/Shower Dishwasher Water Softener
A
B
C
D
E
F
G
H
I
J
K
Weighted
Average
2.07
2.29
1.70
2.79
1.71
1.39
1.1*9
2.29
1.68
3.10
2.93
2.29
0.36
0.19
0.36
0.23
0.33
0.1*6
0.15
0.32
0.59
0.27
0.31+
0.31
0.1*3
0.38
0.31
0.66
0.1*5
0.26
0.1*7
0.36
0.3l*
0.57
0.55
0.1*7
0.29
0.26
0.31
0.1+1
0.21+
0.39
0.36
0.36
0.1*9
0.1*0
0.51*
0.39
0.08
-
0.06
0.02
—
—
0.05
0.21*
—
-
0.03
0.03
toilet usage determined in this study is the result of a lower frequency of
usage which is felt to have been caused by the residents using toilet facili-
ties outside of their homes.
A-25
-------
TABLE A-21. INDIVIDUAL EVENT WATER USAGE, L/cap/day
Family
Unit
A
B
C
D
E
F
G
H
I
J
K
Weighted
Average
$ of Daily
Flow
Toilet
34
32
21
31
31
23
24
34
29
52
41
34
21
.4
.9
.2
.8
.0
.4
.6
.8
.9
.2
.2
.8
.6$
Bath/
Laundry Shower
47
8
49
28
52
48
15
42
61
35
49
39
24
.6
.3
.5
.7
.9
.0
.9
.3
.2
.9
.1
.7
TABLE A-22.
Event
Toilet
Bath /Shower
Bathroom Sink
Kitchen Sink
Dishwashing
Laak
(1975)
74.8
32.1
7.9
13.6
-
51.0
30.2
27.6
50.3
32.8
21.5
32.9
22.3
26.8
46.1
44.2
37.8
t 23.5$
INVESTIGATOR
WATER USAGE,
Cohen and
Wallman
(1974)
65.0
23.8
68.0
Garbage Grinding
Clothes Washing
28.0
39-7
Dish- Water
Washer Softener Other
18.9
10.2
13.2
18.9
10.6
18.9
14.0
11.0
23.0
20.8
26.8
18.5
11.5$
COMPARISON
L/cap/day
Ligman,
Hutzler
and Boyle
(1974)
75.6
47.2
-
—
13.2
5.7
37.8
23
_
15
8
_
_
12
59
_
_
17
9
6
OF
.0 39.
15.
.1 20.
.7 17.
29.
15.
.9 12.
.3 18.
16.
15.
.8 35.
.8 20.
.1$ 12.
EVENT
3
1
4
0
9
5
5
5
6
9
9
4
7$
Bennett and
Linstedt
(1975)
55.6
32.9
18.9
9.8
4.2
3.0
43.8
Water Softening -
Miscellaneous
Total
-
156
-
197
-
180
-
168
Total
214
96
147
155
157
127
113
188
158
170
215
161
100$
This
Study
34.
37.
-
-
18.
-
39.
9.
20.
161
8
8
5
7
8
4
Total daily water use—The total per capita water use at each home is
presented in Table A-23. As shown, the per capita usage was found to be quite
variable at a given home, as evidenced by the large standard deviations and
wide 90$ confidence intervals determined. It is interesting to note, however,
that the 90$ confidence interval for all homes combined was relatively narrow,
154 to 168 L/cap/day (40.7 to 44.4 gal/cap/day) for a mean value of l6l L/cap/
day (42.6 gal/cap/day).
A-26
-------
TABLE A-23. DAILY PER CAPITA WATER USAGE, L/cap/day
Family
Unit
A
B
C
D
E
F
G
H
I
J
K
Weighted
Average
Family
Members
li
3
1*
6
3
5
7
3
5
7
^
Days
28
Ik
77
lf-2
28
28
35
21*
28
68
62
Mean
214
96
ll*7
155
157
127
113
188
158
170
215
l6l
S.D.
98
1*7
88
1*7
113
71
1*5
55
61
k3
112
81*
90#
185
76
130
11*3
122
105
100
169
139
162
192
151*
C.I.
- 21*5
- 117
- 163
- 167
- 192
- 150
- 125
- 206
- 177
- 179
- 239
- 168
To illustrate the variation in per capita usage between homes, the mean
and 90% confidence intervals for each are presented in Figure A-6.
0
10
GAL./CAR/DAY
20 30 40 50 60 70 80
A
B
C
D
FAMILY UNIT p
G
H
1
J
K
AVERAGE
_. j-
- i i i i i i i i i i i
0 50 100 150 200 250 300
DAILY WATER USE, L/CAR/DAY
Figure A-6. Daily water usage.
As shown, the mean daily usage varied from a low of 96 L/cap/day (25.^ gal/
cap/day) for Family B to a high of 215 L/cap/day (56.9 gal/cap/day) for Family
K. Importantly, however, is the fact that for 8 of the 11 homes, the upper
limit of the 90$ confidence interval was less than 189 L/cap/day (50 gal/cap/
day) and in no homes was it greater than 2k6 L/cap/day (65 gal/cap/day).
A-27
-------
The daily per capita water use values determined in this study were com-
pared to the results of earlier investigators. As shown in Table A-22, there
is good agreement "between investigators regarding average per capita water use,
with the mean values varying from a low of 156 L/cap/day (Ul.3 gal/cap/day)
to a high of 197 L/cap/cay (52.1 gal/cap/day).
Further to comparing the study averages, the mean daily water usage
determined for each of the individual households involved in the studies by
Cohen and Wallman (197*0, Laak (1975) and Bennett and Linstedt (1975) were
analyzed in combination with the results of this study. In total, the mean
daily water use for each of 28 homes ranging in size from two to seven members
was available for analysis. A statistical analysis of the per capita water
use values yielded a mean of 180 L/cap/day (1*7-5 gal/cap/day) with a 95% con-
fidence interval of 153 to 205 L/cap/day (U0.6 to 5^.3 gal/cap/day). Consid-
ering the variation in characteristics which existed for these 28 families,
the 95% confidence interval is surprisingly narrow.
Although a variety of factors appear to influence the total quantity of
water used within a home, family size has been suggested as a major factor.
An analysis of the data from the 28 homes was conducted to determine if water
usage could be more accurately predicted by a relationship including family
size compared to that based on a per capita usage. The data were first plotted
as total family water use versus family size (Figure A-7). Although the data
were somewhat scattered, a relationship of the following form appeared to
represent the data,
Q = KX + K2P (1)
where, Q = Total daily family water use (L/day)
K = Base usage (L/day)
K2 = Per capita usage (L/cap/day)
P = Number of family members
A regression analysis conducted on the data yielded the following expression,
Q = 293 + 97 P (2)
with a standard error of estimate equal to 189 and the 95% confidence limits
on the parameters KI and K2 equal to ± 225 and ± 52, respectively. This re-
lationship has been graphically presented in Figure A-7 with the 90% and 95%
confidence lines for an estimate of Q at a given P.
The two-variable relationship (2) appears to offer a more accurate esti-
mate of average household water use for the smaller (2 member) and larger
(5 to 7 member) family sizes than the simpler per capita expression (l).
However, for family sizes of 3 to U members, the estimates provided by both
are similar.
A-28
-------
I
UJ
1500
1250
1000-
750
UJ
I 500
250
T
T
0
0-WALLMAN 8 COHEN (1974)
D-LAAK(I974)
O-8ENNET 8 LINSTEDT(I975)
A-THIS STUDY
95 % C. Lr
90% C.L.
x
O
^d
£
o
Q=293+97P
A
90%C.L
95%C.L.
I
I
234567
FAMILY SIZE,NUMBER OF MEMBERS
8
400
300
o
>v
Z
200 5
100
0
Figure A-7. Mean household water use versus family size.
A-29
-------
Daily and weekly vater use patterns—Utilizing the data generated in this
study, graphs were constructed to illustrate household water use variations
during the day and from day-to-day. The graphs presenting a summary of all
eleven homes combined are presented in Figures A-8 and A-9. The graphs for
each individual home may be found in Attachment A of this appendix. As would
be expected, the fluctuations in the eleven home summary plot are attenuated
and not as extreme as those exhibited by each of the individual households.
15
* 10
V.
Q.
U
4r
T-TOILET
L- LAUNDRY
B-BATH/SHOWER
D - DISH WASH
W-WATER SOFTENER
0-OTHER
9 N 3
TIME OF DAY
MN
Figure A-8. Daily water use pattern,
The daily flow pattern (Figure A-8) shows high water usage in the morning
and evening hours with lower usage during late evening, early morning and
afternoon periods of the day. The miscellaneous or other flow was quite con-
stant and was generally prevalent from 6 a.m. to midnight. Toilet flushing
followed a similar pattern. Laundry was largely concentrated in the morning
between T a.m. and 2 p.m., while baths and showers were most prevalent in the
evening hours between 5 p.m. and midnight. Dishwashings were measured in
three peaks following mealtimes, with the largest flow between 5 and T p.m.
The water softener was concentrated between midnight and 5 a.m.
Little day-to-day variation in flow occurred for any of the events
studied except bathing and clothes washing (Figure A-9) • Bathing showed a
significant difference between Friday (30.2 L/cap/day) and Saturday (1*5.7
L/cap/day). Clothes washing flows were significantly higher on Monday. When
considering total daily flow, no one day was significantly'different from the
average.
A-30
-------
200
150
cr
i
i 1001
AVERAGE
DAIiy FLOW
1 LOWER 90%
CONFIDENCE
LIMIT
BATH/SHOWER
CLOTHES WASH
TOILET
OTHER
i DISH WASH
WATER SOFTENER
j
SAT.
Figure A-9- Weekly water use patterns.
Seasonal variation—Water use data for three of the homes (C,J,K) were
obtained during both the summer and winter seasons to allow an investigation
of potential seasonal variations. It was believed that lifestyle changes
between summer and winter, including daily school attendance by children
during the winter, might result in a significant difference in water usage. A
summary of the water usage for the homes as measured during the winter and
summer seasons is presented in Table A-2*t. A review of the data collected in
consultation with the homeowners led to the conclusion that households demon-
strate widely varying characteristics and habits which are more important in
determining water usage than the season of the year.
Wastewater Quality Characterization; Chemical/Physical—
Individual event wastew_ater— Quality characteristics are reported as
pollutant contributions by event occurrence and per capita per day with the
mean results determined, presented in several ways: concentration per event,
mass/event, mass/cap/day and percent contributed per event. In Table A-25,
the average concentrations (mg/L) measured for each pollutant are presented.
The mean mass (mg) of each pollutant produced by a single occurrence of each
event are presented in Table A-26. In Table A-27 the daily per capita mass
contributions (mg/cap/day) are shown, with the percentages of the total daily
contribution presented in Table A-28.
A-31
-------
TABLE A-2l*. SEASONAL WATER USE COMPARISON, L/cap/day
Family Water Confidence
Unit Toilet Laundry Bath Dishes Softener Other Total Interval Days
c
Summer
C
Winter
J
Summer
J
Winter
K
Summer
K
Winter
23
19
57
111*
35
k9
53
U5
35
38
k9
U9
32 15
22 11
1*5 21
U8 21
39 26
51 28
15 2k
6 17
17
19
11 28
26 1+6
170
119
170
171
188
250
lU6 - 19U
99 - lUo
159 - 182
158 - 183
165 - 212
207 - 293
k2
35
1+2
26
35
27
TABLE A-25. MEAN POLLUTANT CONCENTRATIONS, mg/L
Toilet Flush Kitchen Automatic Clotheswasher
Garbage Sink Dish Bath/
Parameter Fecal Nonfecal Disposal Usage Washer Wash Rinse Shower
BOD5 U
BOD5 F
TOG U
TOC F
TS
TVS
TSS
TVSS
TOT-N
NH3-N
N03-N
TOT-P
Ortho-P
Temperature
Flow*
Number of
Samples
610
330
500
220
1500
1090
880
T20
210
8U
.9
38
16
66°F
16.3
32-1*0
330
200
220
160
910
610
320
260
1^0
2T
1.1
lU
10
66°
16.3
2)4-37
1030
2UO
690
3TO
2*430
22TO
11*90
12TO
60
.9
0
12
8
71°
lU.U
U-7
lU6o
800
880
T20
2U10
1710
720
6TO
T^
6
.3
TU
31
80°
18.1
7-H
10UO
650
600
390
1500
8TO
UUO
3TO
ho
U.5
.3
68
32
101°
l45.it
13-15
380
250
280
190
13^0
520
280
170
21
.7
.6
57
15
90°
59.3
21+-2T
150
110
100
T2
1+10
180
120
69
6
A
.U
21
h
83°
5^A
2U-28
170
100
100
61
250
190
120
85
17
2
.U
2
1
85°
U9.1
18-2U
JA
Flow values were determined in the wastewater quality study and are in Liters,
A-32
-------
TABLE A-26. ME/IN POLLUTANT CONTRIBUTIONS, mg/event
Toilet Flush.
Parameter
BOD5 U
BOD^ F
TOG U
TOC F
TS
TVS
TSS
TVSS
TOT-N
NH--N
NO^-N
TOT-P
Ortho-P
Fecal
10000
5390
8l60
36^0
24600
17900
11*1*00
11700
3**60
1380
15
620
260
TABLE A-27
Nonfecal
5360
33^0
3520
2660
15000
10100
5280
1*300
2230
UUO
18
230
160
Garbage
Disposal
11*600
3l*30
9800
521*0
31*500
32200
21200
18100
850
13
0
170
110
Kitchen
Sink
Usage
26800
ll*700
16000
13200
1*1*200
31200
13200
12300
1350
110
6
1350
560
. MEAN PER CAPITA POLLUTANT
Toilet Flush
Parameter
BOD5 U
BODc F
TOC U
TOC F
TS
TVS
TSS
TVSS
TOT-N
NH--N
NO^-N
TOT-P
Ortho-P
Fecal
1*3^0
231*0
3530
1580
10700
7760
62UO
5090
1500
590
6.3
270
120
Nonfecal
6380
3980
1*250
3170
17800
12000
6280
5120
261*0
520
21.1
280
190
Garbage
Disposal
10900
2570
7320
3910
25800
21*000
15800
13500
630
9.6
.2
130
90
Kitchen
Sink
Usage
83l*0
1*580
5000
1*110
13800
9730
1*110
381*0
1*20
32.3
1.8
1*20
180
Automatic
Dish
Washer
1*7500
29500
27300
17600
68300
39600
19800
16700
1820
210
lU
3090
ll*6o
Clothe swasher
Wash
22900
1U900
16UOO
111*00
79800
31200
16900
10000
1250
U2
36
3UOO
900
Rinse
8210
5820
5330
3920
22500
98UO
6260
3750
330
22
22
llUo
220
Bath/
Shower
8230
U980
1*680
3010
12200
9560
6020
Ul90
8UO
99
20
99
U9
CONTRIBUTIONS, mg/cap/day
Automatic
Dish
Washer
12600
781*0
7280
1*690
18200
10500
5270
1*1*60
1*90
51*
U.I
820
380
Clothe swasher
Wash
10800
6970
7700
5380
37500
ll*700
7930
U700
580
19. u
17
1600
UiO
Rinse
1*010
28UO
2610
1910
10900
U800
30UO
1810
150
11. U
10.3
550
110
Bath/
ShoVer
3090
1870
1750
1130
U590
3600
2260
1580
310
UO
7.U
36
20
A-33
-------
TABLE A-28. MEAN PER CAPITA POLLUTANT CONTRIBUTIONS, % OF TOTAL DAILY
Parameter
BOD5 U
BODc F
TOG U
TOC F
TS
TVS
TSS
TVSS
TOT-N
HH--N
NO^-N
TOT-P
Ortho-P
Toilet
Flush
/"I "L _ _ —
— — — — vjai"uag,c
Fecal Nonfecal Disposal
8.8
7.7
11.0
7.2
9.U
12.3
17.8
19.1
2^.6
k6.1
9.3
6.8
8.2
12.9
13.1
13.2
lU.U
15.7
19.0
17.9
19.3
1+3.5
Ui.o
31.0
7.0
13. ^
Kitchen
Sink
L Usage
16.8
15.0
15.6
18.7
12.1
15 A
11.7
1UA
7.0
2.5
2.6
10.6
12.6
Automatic
Dish
Washer
25.5
25.8
22.7
2lA
16.0
16.7
15.
16.8
8.0
U.2
6.0
20.6
27.2
: Clothe swasher
Wash
21.7
22.9
2U.
2U.5
33.1
23.3
22.5
17.7
9.5
1.5
25.
U0.3
29.2
Rinse
8.1
9.3
8.1
8.7
9.6
7.6
8.7
6.8
2.U
.9
15.2
13.8
7.9
Bath/
Shower
6.2
6.2
5.U
5.1
U.I
5.7
6.U
5.9
5.0
3.2
10.9
.9
1.5
Garbage disposal results are not included.
It should "be emphasized that (l) all results presented were based on direct
measurement except for mass/cap/day values which necessarily included some
assumptions concerning event frequencies of occurrence, and (2) the contribu-
tions of pollutants from the carriage waters were removed from all results.
The results shown in the mean value tables (Tables A-25 to A-28) indicate
how the mean concentrations and mass loadings contributed vary between the
different types of household events. This variation in event wastewater qual-
ity is as expected, based on the variable nature and origin of the wastewaters.
A statistical analysis was conducted for each type of event and the mg/
cap/day contributions of the various parameters. These results are included
in Attachment B of this appendix. Based on this analysis, the dispersions
about the mean values were found to be significant as evidenced by large
standard deviations and wide ranges. For example, the mean mg/cap/day unfil-
tered BODc loading from the bath/shower event based on 22 samples was 3090
with a standard deviation of 2lUO and a range of 790 to 69^0 mg/cap/day. This
is as expected in light of the variation in day-to-day habits at a given home
and the variation in life styles between homes.
The mean results of this study were reviewed on an individual event basis
and compared to the results obtained by earlier investigators. The comparisons
were rather scant in many cases, since many of the parameters measured in this
study were not reported in the earlier studies.
Toilet flushing—Ike separation of the toilet flush event into a fecal^
flush and a nonfecal flush was possible through visual inspection of the toilet
flush samples. The fecal flush contributed lower mass/capita/day loadings than
-------
the nonfecal flush, principally because the latter occurred approximately 2.6
times as often. The total output from the toilet (fecal and nonfecal flushes)
vas found to contribute 21.7$ of the unfiltered BOD5> 35.7$ of the suspended
solids, 68.1$ of the total nitrogen and 13.8$ of the total phosphorus produced
daily by a given home (Table A-28). When compared to the results of earlier
investigators, the mean mg/cap/day values determined in this study were in
general, found to be substantially lower (Table A-29). However, when compared
on a mg/event basis, as in Table A-30, the results were in fair agreement.
The method of determining the toilet wastewater concentrations and daily per
capita contributions is believed to be the cause of this. Most of the earlier
studies (Laak, 1975; Ligman, Hutzler and Boyle, 197^; and Bennett and Linstedt,
1975) determined the pollutant contributions from the toilet from a small
number of analyses of individual samples of urine and feces, medical literature
characterizing human waste products and user estimates of event frequency.
The single study which actually sampled raw toilet wastewaters (Olsson,
Karlgren and Tullander, 1968), also employed user estimates of event frequency
to determine mass/cap/day contributions. In contrast, the mass/cap/day con-
tributions determined in this study were based on actual on-site sampling of
toilet wastewaters as well as measurement of event frequencies.
TABLE A-29. TOILET FLUSH WASTEWATER - INVESTIGATOR COMPARISON, mg/cap/day
Parameter
BOD5
TSS
TOT N
TOT P
Olsson, Karlgren
and Tullander Laak Ligman, Hutzler
(1968) (1975) and Boyle (197*0
20000
30000
11000
1600
23500
1^500
2110
23600
30900
16800
1360
Bennett and
Linstedt This
(1975) Study
6900
36500
5200
10700
12500
kiko
550
TABLE A-30. TOILET FLUSH WASTEWATER - INVESTIGATOR COMPARISON, mg/event
Parameter
BOD5
TSS
TOT N
TOT P
Olsson, Karlgren
and Tullander
(1968)
hOOO
6000
2200
320
Bennett and
Laak
(1975)
U360
_
2680
390
Li gman , Hut zl e r
and Boyle (197*0
6380
83^0
1*51*0
370
Linstedt
(1975)
1920
10100
1*170
-
This
Study
67ltO
7870
2600
3^0
uses/cap/day
5.0
5.U
3.7
3.6
1.6
Dishwashing—The wastewater produced from the kitchen sink was the result
of manual dishwashing and major dish rinsing (pots and pans) at homes having
automatic dishwashers. Thus, the total mass/cap/day contributions from dish-
washing are represented by the sum of the kitchen sink and automatic dishwasher
contributions. Dishwashing proved to be a major contributor of pollutants,
A-35
-------
generating
of the unfiltered BOD, 26.7$ of the suspended solids and
of the total nitrogen and 31.2$ of the total phosphorus. When compared to the
values reported by earlier investigators, the results of this study were found
to be significantly higher (Table A-31). However, most of the reported values
of earlier investigators are within the range of values determined in this
study. The discrepancy in the BOD,, results, as well as in the results for the
other parameters, were most likely caused by the normal differences in the life
style and dishwashing habits of the families whose homes were sampled.
TABLE A-31. DISHWASHING WASTEWATER - INVESTIGATOR COMPARISON, mg/cap/day
Pollutant
BOD,.
TSS'
TOT N
TOT P
Olsson, Karlgren
and Tullander
(1968)
17000
13000
600
300
Contributing
Events :
Kitchen Area
Laak
(1975)
9200
50-400
Manual
Dish-
washing
Ligman, Hutzler
and Boyle (197*0
5900
2700
450
Manual
Dishwashing
Bennett and
Linstedt
(1975)
11100
2200
1100
Dishwasher,
Kitchen
Sink
This
Study
21000
9380
910
1240
Dish-
washer
Kitchen
Sink
Garbage disposal—The garbage disposal results presented in this study are
based on the analysis of samples taken from the garbage disposal wastewaters
produced by homes without automatic dishwashers. The results obtained in this
study were lower than expected, based on earlier analyses performed by Ligman,
Hutzler and Boyle (197*0 and Bennett and Linstedt (1975) (Table A-32). An
explanation as to the reason for this may be found in the fact that the
families which had garbage disposals in this study, also had large dogs.
Consultation with the homeowners revealed that a majority of the meal scraps
which might otherwise have been disposed of through the garbage disposal were
fed to the dogs. Since the use of garbage disposals in rural homes served by
TABLE A-32. GARBAGE DISPOSAL WASTEWATER - INVESTIGATOR COMPARISON, mg/cap/day
Parameter
BOD,-
TSS
TOT N
TOT P
Ligman, Hutzler
and Boyle (1974)
30900
43600
910
-
Bennett and
Linstedt (1975)
12300
20200
200
-
This
Study
10900
15800
630
130
uses/cap/day
0.75
0.40
0.75
A-36
-------
individual sewage disposal systems is discouraged and since the results ob-
tained for the garbage disposal in this study were based on a limited number
of samples, the garbage disposal results were omitted when calculating the
total mass/cap/day loadings from a typical rural household and the percentages
contributed by the individual events,
Clothes washing—Based on the results obtained in this study, the house-
hold operation of washing clothes proved to be a major contributor of pollut-
ants. On a mass/cap/day basis, the automatic clothes washer contributed 29.8$
of the unfiltered BODc, 31.2$ of the suspended solids, 11.9$ of the total
nitrogen and 5^.1$ of the total phosphorus (Table A-28). In each case,
approximately 70$ of the pollutants were contained in the wash-cycle discharge
with the remaining 30$ in the rinse-cycle discharge (Table A-26). The results
obtained in this study (wash and rinse cycles combined) were compared to those
of earlier investigators and were found to be somewhat higher on a mg/cap/day
basis (Table A-33). When compared on a mg/event basis, however, the results
are in fair agreement. The discrepancy in per capita contributions is due to
the different event frequencies used in their computation.
TABLE A-33. LAUNDRY WASTEWATER - INVESTIGATOR COMPARISON, mg/cap/day
Parameter
BOD5
TSS
TOT R
TOT P
Ols son, Karlgren
and Tullander Laak Ligman , Hutzler
(1968) (19T5 ) and Boyle (197^)
3000
2000
200
1300
7900 9500
7260
-
2270
Bennett and
Linstedt This
(1975) Study
8700
31*00
200
-
1U800
11000
730
2150
uses/cap/day ? 0.30 0.25 0.30 O.U8
Bath/Shower—The results for the bath/shower event, based on samples of
individual bath and shower events grouped together, proved it to be a minor
contributor of pollutants. On a daily basis, this event contributed the
lowest percentage of almost all pollutants measured: 6.2$ of the unfiltered
BOD , 6.lj$ of the suspended solids, 5-0$ of the total nitrogen and less than
1.0$ of the total phosphorus (Table A-28). The pollutant contributions
determined in this study were found to be within the range of values reported
by earlier investigators (Table A-3^-).
Daily pollutant contributions—Of prime importance to many individuals
are the total daily pollutant contributions of an individual within a typical
household. The results determined in this study, as well as those reported by
previous investigators, for BOD,-, suspended solids, phosphorus and nitrogen
are presented in Table A-35. It should be noted that the pollutant contribu-
tions of household garbage disposals have been excluded from the results
presented. It is interesting to note how closely the results generated by the
various investigators agree. As noted previously, the lower nitrogen contribu-
tion determined in this study is for the most part due to the frequency of
toilet usage.
A-37
-------
TABLE A-31*. BATH/SHOWER WASTEWATER - INVESTIGATOR COMPARISON, mg/cap/day
Parameter
BOD
TSS5
TOT N
TOT P
uses/cap/day
Laak
C19T5)
6180
:
7
Ligman, Hutzler
and Boyle (197*0
9100
5**50
-
0.51
Bennett and
Linstedt (1975)
3200
900
0
0.32
This
Study
3090
2260
310
UO
0.39
TABLE A-35. DAILY POLLUTANT CONTRIBUTIONS,* gram/cap/day
Pollutant
Olsson, Karlgren Bennett and
and Tullander Ligman, Hutzler Laak Linstedt This
(1968) and Boyle (197*0 (1975) (1975) Study
BOD
Suspended
Solids
Nitrogen
Phosphorus
U5.0
1+8.0
12.1
3.8
1*8.1
U6.3
16.8
U.I
1*8.6 3**. 8
**7.3
7.2
-
1*9.6
35.1
6.1
U.O
Garbage disposal contributions have been excluded.
The use of a garbage disposal can substantially increase the quantities
of pollutants shown in Table A-35- Based on investigations by Ligman, Hutzler
and Boyle (197*0, Bennett and Linstedt (1975), and the results of this study,
the increase in pollutant contributions that can be expected due to the use
of a garbage disposal have been outlined in Table A-36. As shown, the use of
a garbage disposal dramatically increases the contribution of BODc and sus-
pended solids while adding little additional nitrogen and phosphorus.
TABLE A-36. INCREASE IN POLLUTANT MASS DUE TO
GARBAGE DISPOSALS, grams/cap/day
Pollutant
BOD5
Suspended Solids
Nitrogen
Phosphorus
Ligman, Hutzler
and Boyle (197*0
30.9 (61**)*
**3.6 (9!**)
.9 (5«
-
Bennett and
Linstedt (1975)
12.3 (3556)
20.2 (U3J6)
.2 (356)
.1 (3%)
This Study
10.9 (22J6)
15.8 (1*5*)
.6 (10J6)
.1 (3*)
* Percentage increase of the corresponding value shown in Table A-35.
A-38
-------
Hourly pollutant distributions—Since individual water-using events occur
intermittently and contribute varying quantities of pollutants, the strength
of the waste-water generated from a home fluctuates during the day. To illus-
trate patterns for the fluctuations of various pollutants, the mass/cap/day
results of this phase of the study were combined with the results of the water
use characterization phase. In determining the hourly distribution of various
pollutants, it was assumed that the mass/cap/day generated by an event was, on
the average, distributed evenly in the daily flow from the event. The percen-
tage of the daily flow generated during a given hour from a given event was
multiplied times the mean mg/cap/day loading of a given pollutant to determine
the mass of the pollutant produced during the hour in question. This was done
for the toilet, automatic clothes washer, bath/shower and dishwashing events
for each hour of a typical day for BODc, suspended solids, total nitrogen and
total phosphorus, as shown in Figures A-10 through A-13. It should be noted
that these graphs are similar to the summary water use patterns developed
(Figures A-8, A-9) and the fluctuations, in this case in wastewater quality,
for an individual home are likely to be considerably greater than those shown
in the summary graphs.
400O
Q.
O
~o> 3000
E
in
Q
O
CO
Q
Ul
-------
T TOILET
L LAUNDRY
400Or- B BATH or SHOWER
KS KITCHEN SINK
DW DISWASHER
d.
o
o>3000
co"
Q
o aooo
CO
Q
UJ
Q
1000
V)
^
CO
MN
9 NOON 3
TIME OF DAY
Figure A-11. Hourly distribution of suspended solids,
Q.
O
^
O>
E
4OO
3OO
UJ
O 20°
o:
£
o
100
T
L
B
KS
TOILET
LAUNDRY
BATH or SHOWER
KITCHEN SINK
DW DISHWASHER
MN
9 NOON 3
TIME OF DAY
MN
Figure A-12, Hourly distribution of total nitrogen.
-------
e/
IT
O
40O
300
20O
<
O
T TOILET
L LAUNDRY
- B BATH or SHOWER
KS KITCHEN SINK
OW DISHWASHER
Figure A-13. Hourly distribution of total phosphorus,
Wastewater Quality Characterization: Microbiological—
The results of analyses for total and fecal coliforms and fecal strep-
tococci on bathing and clothes washing samples obtained from six study house-
holds are summarized in Table A-37.
TABLE A-37- BACTERIOLOGICAL CHARACTERISTICS OF BATH AND LAUNDRY WASTEWATERS
Event
Clothes
Washing
Bathing
Organism
Total Coliforms
Fecal Coliforms
Fecal Streptococci
Total Coliforms
Fecal Coliforms
Fecal Streptococci
Samples
Ul
in
in
32
32
32
Mean*
#/100 mL
215
107
77
1810
1210
326
Confidence
#/10
95$
65 - 700
39 - 295
27 - 220
710 - 1*600
1*50 - 321*0
100 - 1050
Intervals,*
0 mL
99%
1*5 - 1020
28 - 1*05
19 - 305
530 - 6l60
330 - 1*1*10
70 - 1510
* Log-normalized data.
f
Samples were obtained from the middle of the wash cycle. Samples taken from
15 rinse cycles were consistently lower than the corresponding wash cycle
values.
A-Ul
-------
These results demonstrate that indicator organisms typically associated with
fecal contamination can be expected in raw bath and laundry wastewaters. The
higher numbers in the bathing event appear to be primarily associated with the
bathing of infants and children. The relatively low clothes washing numbers
are in large part, due to the use of hot water laundry cycles,
In addition to the results shown in Table A-37, several isolates from the
bathing and clothes washing (wash and rinse cycles) samples obtained at three
of the study homes (c", G, I) were characterized. Sixty-one fecal coliform
isolates were obtained from wash and rinse laundry wastewaters and character-
ized as 65% Escherichia spp. (mainly E_. coli), 21% Klebsiella pneumonia (with
the ability to grow at 1A.5°C), 5% high temperature Enterpbacter aerogenes
biotypes, and 2% Citrobacter freundii. Approximately 9Of" of the 2k fecal
coliform isolates from bath waters were Escherichia spp. with the remainder,
Klebsiella pneumonia. Enterobacter, Klebsiella, Citrobacter and Escherichia
spp. were isolated from m-Endo (TC) plates of bath, wash and rinse wastewater
samples.
Forth-eight streptococcal isolates were obtained from bath, wash and
rinse wastewater samples. Enterococci made up 38$ of these isolates; the
majority of the bath enterococci were S_. faecalis var. liquefaciens, whereas
only a few of the enterococcal isolates taken from clothes wash and rinse
wastewaters were of this species. Twenty-two percent of streptococcal iso-
lates were characterized as S_. bovis. Other streptococcal species generally
found on and in the body of animals and man (Viridens and Pyogenic groups)
were also isolated.
Much of the bacterial contamination in these bath and clothes washing
wastewaters was probably from the natural environment or natural skin flora of
man as indicated by the incidence of S_. faecalis var. liquifaciens, S_. bo vis
and other nonfecal streptococcal isolates found. Many of these organisms,
though associated with animal feces, are often considered to exist in nature
and probably have less sanitary significance than other enterococcal species.
However, the high incidence of E_. coli, Klebsiella and enterococci, especially
in wash and rinse wastewaters, indicates that these wastewaters possess a
"potential" for fecal contamination.
Analyses were performed on the samples obtained from the remaining three
study homes (L, M, N) for two common potential pathogens, Fseudomonas
aeruginosa and Staphylococcus aureus. The results as shown in Table A-38
indicate a very low incidence of Pseudomonas aeruginosa and in those samples
where it was isolated, the concentrations were always less than 20/100 mL.
Staphylococcus aureus was not isolated in any of the samples analyzed.
The results of the in-house sampling at Home N of wastewaters generated
through hygienic care of an infant who had just received an oral polio vaccina-
tion are summarized in Table A-39. In addition to the infant sample results
shown several samples were obtained from the bathing and clothes washing
events of the two adult residents. These latter samples yielded total and
fecal coliform and fecal streptococci concentrations within the range of values
determined previously (Table A-37)•
A-U2
-------
TABLE A-38. PSEUDOMQNAS AERUGINOSA AND STAPHYLOCOCCUS
AUREUS IN BATH AND LAUNDRY WASTEWATER
Bathing
Laundry
Organism
Positive Highest Positive Highest
Home Samples Samples Value Samples Samples Value
Pseudomonas
aeruginosa
Staphylococcus
aureus
L
M
N
L
M
N
10
1
10
9
1
10
2
0
0
0
0
0
2/100 mL
*a
**>
*c
*d
*c
17
1*
5
17
k
h
5
0
0
0
0
0
20/100 mL
*b
*b
*c
*e
*e
* Below detention limit of test which was: a2/100 mL; b20/100 mL; °10/100 mL
for 3 samples and lOVlOO mL for the remaining; loVlOO mL; S10/100 mL.
To properly interpret the data shown in Table A-39 requires consideration of
the relationship of the events sampled. This relationship was established
based on in situ measurements and is graphically depicted in Figure A-l^.
The diapers containing stool samples were thoroughly rinsed in the toilet
prior to their disposition in a diaper pail containing approximately 7 liters
of water and one tablespoon of baking soda. Thus, the majority of the fecal
material on the diapers was flushed down the toilet. Prior to this rinsing,
a sample of the fecal material was taken. Diapers soiled by urine alone were
deposited directly into the diaper pail. After 2k-kQ hours of collecting
diapers in the pail, the diapers were swished around in the pail and a portion
of the liquid fraction was poured off into the toilet (about 3 liters from
which a sample was taken). The remaining liquid and diapers were deposited
into the clothes washer (17 to 35 diapers and approximately k liters of
liquid). Two of the laundry samples included a few baby clothing items also.
The cleaning product used was 3A cup of Dreft. Prior to the end of the
laundry wash cycle, a sample of the washer contents was taken. Samples of
the infant's bath water were taken after bathing prior to discharge of the
bath water.
As shown in Figure A-lk, the laundry effectively yielded a one log reduc-
tion in the concentration of organisms measured in the diaper pail by dilution
alone. However, as shown in Table A-39, total and fecal coliforms were re-
duced by about 8 logs, fecal streptococci were reduced by about 2 logs, and
virus were reduced by about 2 logs. These reductions were probably due in
large part to the "hot" laundry cycles which were routinely used (temperature =
60°C). Of special note, are the very low levels of indicator bacteria and
the absence of virus in all of the laundry-wash cycle samples. The analysis
of bathing samples yielded concentrations within the range of values deter-
mined previously for the selected indicator bacteria. Surprisingly, virus
was only isolated in one of five samples at a low level of 5 PFU/mL.
-------
TABLE A-39. MICROBIOLOGICAL CHARACTERISTICS
OF INFANT RELATED WASTEWATERS*
Event
Diaper Pail
Bathing
Laundry
(wash cycle)
Stool
Samplet
Total
Col if onus
Log no./
100 mL
8.71
(6)
7.^3-9.98
3.93
(U)
1.95-5.92
0.38
(5)
0.15-0.60
11.01
(7)
10.17-11.86
Fecal
Coli forms
Log no . /
100 mL
8.67
(6)
7. 1*0-9. 91*
3.93
(U)
1.95-5.92
0.38
(5)
0.15-0.60
10. 91*
(7)
10.l6-ll.72
Fecal
Strep .
Log no./
100 mL
2.65
(6)
1.58-3.73
U.U8
CO
3.25-5.71
<1.0
(5)
-
11.61*
(7)
11.39-11.88
Pseudomonas
aeruginosa
Log no./
100 mL
<1.30
(6)
-
<1.30
(U)
-
<1.30
w
-
<2.08
(6)
-
Virus
Infectivity
PFU/mL
2.55
(7)
2.17-2.93
_
1 sample -
0.70
U samples -
none detected
6 samples -
none detected
5.86
(8)
5.36-6.35
* Log normalized data; mean
(number of samples)
95$ CI
t Stool sample values expressed per wet gram.
DIAPERS
W/FECES
DIAPERS
W/O FECES
BABY CLOTHING,
BEDDING,...
Figure A-lU. Infant related wastewater sample relationships,
-------
CHARACTERISTICS OF WASTEWATERS GENERATED BY RURAL ESTABLISHMENTS AND
PUBLIC FACILITIES
The rural population, as well as the transient population moving through
the rural areas, require the services offered "by a variety of commercial es-
tablishments and facilities. As a result, these establishments and facilities
are commonly located in unsewered areas and are forced to rely on some form of
private sewerage for disposal of their wastewaters. Obviously, the list of
establishments/facilities which could potentially be located in the rural
areas is a lengthy one. However, certain establishments appear to be located
in rural areas only infrequently, while others appear sufficiently similar to
a residential household in terms of their waste producing sources that their
wastewater characteristics should likewise be similar. Of special interest
are those establishments/facilities which appear to occur frequently in un-
sewered locations and generate wastewaters whose characteristics may be con-
siderably different from that of a typical household. The establishments
selected for this investigation include:
Bars/Taverns Motels
Bowling alleys Restaurants
Campgrounds and picnic parks Schools
Churches Service stations
Country (golf) clubs Shopping centers
Laundromats Sports facilities
Marinas Theaters
Initially, a major effort was expended to compile a comprehensive summary
of existing water use/wastewater production characterization data. Subsequently,
methodologies for estimating wastewater production at facilities serving tran-
sient populations were considered and evaluated as to their feasibility and
appropriateness, and the existing characterization data base was expanded where
necessary and feasible.
Summary of Existing Information
To determine the extent of the present data base for each of the estab-
lishments under investigation, a review of the literature was conducted and
inquiries were made to various possible sources of information. A listing of
the literature searched and a summary of those individuals and organizations
contacted either by telephone or letter may be found in Attachment C of this
Appendix. Based on the literature reviewed and the contacts made, a compre-
hensive summary of the existing information was compiled.
General Guideline Information—
A substantial number of references were found to contain guidelines for
estimating the characteristics of wastewater produced by various public es-
tablishments . Lengthy tables such as the one found in the Manual of Septic
Tank Practice^ (19&7) were found in many standard texts, equipment manufac-
turers' catalogs and government regulatory codes. These guideline tables
usually only present suggested daily flows, but a few also list BOD,- and
suspended solids contributions and the duration of flow. A few representative
tables are shown in Tables A-^0 through A-^3.
-------
TABLE A-UO. QUANTITIES OF SEWAGE FLOWS
(Manual of Septic Tank Practice, 1967)
Gal. Per Person Per Day*
Type of Establishment (Unless Otherwise Noted)
Airports (per passenger) 5
Apartments - multiple family (per resident) 60
Bathhouses and swimming pools 10
Camps:
Campground with central comfort stations 35
With flush toilets, no showers 25
Construction camps (semi-permanent) 50
Day camps (no meals served) 15
Resort camps (night and day) with limited plumbing 50
Luxury camps 100
Cottages and small dwellings with seasonal occupancy 50
Country clubs (per resident member) 100
Country clubs (per non-resident member present) 25
Dwellings:
Boarding houses 50
additional for non-resident boarders 10
Luxury residences and estates 150
Multiple family dwellings (apartments) 60
Rooming houses ^0
Single family dwellings 75
Factories (gallons per person, per shift, exclusive
of industrial wastes) 35
Hospitals (per bed space) 250+
Hotels with private baths (2 persons per room) 60
Hotels without private baths 50
Institutions other than hospitals (per bed space) 125
Laundries, self-service (gallons per wash, i.e., per
customer) 50
Mobile home parks (per space) 250
Motels with bath, toilet, and kitchen wastes
(per bed space) 50
Motels (per bed space) ^0
Picnic parks (toilet wastes only) (per picknicker) 5
Picnic parks with bathhouses, showers and flush toilets 10
Restaurants (toilet and kitchen wastes per patron) 10
Restaurants (kitchen wastes per meal served) 3
Restaurants additional for bars and cocktail lounges 2
Schools:
Boarding 100
Day, without gyms, cafeterias, or showers 15
Day, with gyms, cafeteria, and showers 25
Day, with cafeteria, but without gyms, or showers 20
Service stations (per vehicle served 10
Swimming pools and bathhouses 10
(continued)
A-U6
-------
TABLE A-UO (continued)
Type of Establishment
Gal. Per Person Per Day*
(Unless Otherwise Noted)
Theaters:
Movie (per auditorium seat)
Drive-in (per car space)
Travel trailer parks without individual water and
sewer hook-ups (per space)
Travel trailer parks with individual water and
sewer hook-ups (per space)
Workers:
Construction (at semi-permanent camps)
Day, at schools and offices (per shift)
5
5
50
100
50
15
* L/person/day = 3.8 x gal/person/day.
TABLE A-kl. ESTIMATED WATER CONSUMPTION*
(Metcalf and Eddy, Inc., 1972)
Type of Establishment
Gal. Per Day
Per Person
or Unitf
Dwelling units, residential?:
Private dwellings on individual wells or metered supply 50-75
Apartment houses on individual wells 75-100
Private dwellings on public water supply, unmetered 100-200
Apartment houses on public water supply, unmetered 100-200
Subdivision dwelling on individual well, or metered
supply, per bedroom 150
Subdivision dwelling on public water supply, unmetered,
per bedroom 200
Dwelling units, treatment:
Hotels 50-100
Boarding houses 50
Motels, without kitchens, per unit 100-150
Lodging houses and tourist homes Uo
Camps:
Pioneer type 25
Children's, central toilet and bath UO-50
Day, no meals 15
Luxury, private bath 75-100
Labor 35-50
Trailer with private toilet and bath, per unit
(2-1/2 persons)* 125-150
Restaurants (including toilet):
Average 7-10
Kitchen wastes only 2-1/2-3
(continued)
-------
TABLE A-Ul (continued)
Gal. Per Day
Per Person
Type of Establishment or Unit"*"
Short order U
Short order, paper service 1-2
Bars and cocktail lounges 2
Average type, per seat 35
Average type, 2l*-hr, per seat 50
Tavern,per seat 20
Service area, per counter seat (toll road) 350
Service area, per table seat (toll road) 150
Institutions:
Average type 75-125
Hospitals 150-250
Schools:
Day, with cafeteria or lunch room 10-15
Day, vith cafeteria and showers 15-20
Boarding 75
Theaters:
Indoor, per seat, two showings per day 3
Outdoor, including food stand, per car (3-1/3 persons) 3-5
Automobile service stations:
Per vehicle served 10
Per set of pumps 500
Stores:
First 25-ft frontage ^50
Each additional 25-ft frontage UOO
Country clubs:
Resident type 100
Transient type, serving meals 17-25
Offices 10-15
Factories, sanitary wastes, per shift 15-35
Self-service laundry, per machine 250-500
Bowling alleys, per alley 200
Swimming pools and beaches, toilet and shower 10-15
Picnic parks, with flush toilets 5-10
Fairgrounds (based on daily attendance) 1
Assembly halls, per seat 2
Airport, per passenger 2-1/2
* Water under pressure, flush toilets and wash basins are assumed provided
unless otherwise indicated. These figures are offered as a guide; they
should not be used blindly. Add for any continuous flows and industrial
usages. Figures are flows per capita per day. unless otherwise stated.
f L/day = 3.8 x gal/day.
+ Add 125 gal. per trailer space for lawn sprinkling, car washing, leakage,
etc.
A-U8
-------
TABLE A-42. WASTEWATER CHARACTERISTICS FOR PACKAGE TREATMENT PLANT
SIZING (Goldstein and Moberg, 1973)
Type of Facility
Airports - (per passenger)
Airports - (per employee)
Apartments - Multiple family
Boarding Houses
Bowling Alleys - per lane (no food)
Campgrounds - per tent or travel
trailer site - central bathhouse
Camps - Construction - (semi-
permanent)
Camps - Day (no meals served)
Camps - Luxury
Camps - Resort (night and day) with
limited plumbing
Churches - per seat
Clubs - Country (per resident member)
Clubs - Country (per nonresident member
present )
Courts - Tourist or Mobile home
parks with individual bath units
Dwellings - Single-family
Dwellings - Small, and cottages
with seasonal occupancy
Factories - (gallons, per person,
per shift, exclusive of industrial
wastes . No showers . )
Add for showers
Hospitals
Hotels - with private baths (2
persons per room)
Institutions - other than hospitals
(nursing homes)
Laundromat
Motels - (per bed space)
Motels - with bath, toilet, and
kitchen wastes
Offices - no food
Parks - Picnic (toilet wastes only)
(gallons per picnicker)
Parks - Picnic, with bathhouses,
showers, and flush toilets
Restaurants - (kitchen wastes per
meal served)
Restaurants - (toilet and kitchen
wastes per patron)
Flow*
(gal/
cap/
day
5
15
75
50
75
50
50
15
100
50
5
100
25
50
75
50
25
10
250+
60
125
ItOO
ito
50
15
5
10
7
10
, \
#5 Day
B.O.D.T
(ibs/cap/
day)
.020
.050
.175
.1^0
.150
.130
.1^0
.031
.208
.1^0
.020
.208
.052
.lUO
.170
.lUO
.073
.010
.518
.125
.260
varies
.083
.1^0
.050
.010
.021
.015
.021
Runoff
hours
16
16
16
16
8
16
16
16
16
16
it
16
16
16
16
16
8
16
16
16
12
16
16
8
8
8
8-12
8-12
Shock
Load
Factor
low
low
med.
med.
med.
med.
med.
med.
med.
med.
high
med.
med.
med.
med.
med.
high
med.
med.
med.
high
med.
med.
high
high
high
high
high
-------
TABLE A-U2 (continued)
Type of Facility
Restaurants - additional for bars and
cocktail lounges
Schools - Boarding
Schools - Day, without cafeterias,
gyms, or showers
Schools - Day, with cafeterias, "but
no gyms or showers
Schools - Day, with cafeterias,
gyms, and showers
Service Stations - (per vehicle
served)
Shopping Centers - (no food - per
sq. foot)
Shopping Centers - (per employee)
Stores - (per toilet room)
Swimming pools and bathhouses
Sports Stadiums
Theaters - Drive-in (per car space)
Theaters - Movie (per auditorium seat)
Trailer Parks - per trailer
Flow*
(gal/
cap/
day
3
100
15
20
25
12
0.1
15
Uoo
10
5
5
5
150
#5 Day
B.O.D.1"
(ibs/cap/
day)
.006
.208
.031
.0^2
.052
.021
.050
.832
.021
.020
.010
.010
.350
Runoff
hours
8-12
16
8
8
8
16
16
16
16
8
U-8
6
6
16
Srock
Load
Factor
high
med.
high
high
high
med.
med.
med.
med.
high
very high
high
high
med.
* L/cap/day = 3.8 x gal/cap/day.
T" g/cap/day = U5^ x Ibs/cap/day.
TABLE A-U3. SUGGESTED DAILY FLOWS AND BOD CONSIDERATIONS
(Goldstein and Moberg, 1973)
Class
Subdivisions, Better
Subdivisions, Average
Subdivisions, Low Cost
Motels, Hotels, Trlr. Pks.
Apartment Houses
Resorts, Camps, Cottages
Hospitals
Factories or offices
Persons
Per Unit
3.5
3.5
3.5
2.5
2.5
2.5
per bed
per person
gal/cap/
day
100
90
TO
50
75
50
200
20
Ibs BOD5/
cap /day
With
Garbage
Avg. Grinder
0.17 0.25
0.17 0.23
0.17 0.20
0.17 0.20
0.17 0.25
0.17 0.20
0.30 0.35
0.06
~or\T\
-oUJJc-
(mg/L)
205
220
290
Uoo
225
Uoo
200
360
(continued)
A-50
-------
TABLE A-*t3 (continued)
Ibs BOD5/
cap/day
Class
Factories, incl. shovers
Restaurants
Schools , Elementary
Schools, High
Schools, Boarding
Swimming Pools
Theaters , Drive-in
Theaters , Indoor
Airports, Employees
Airports, Passengers
Bars, Employees
Bars , Customers
Dairy Plants
Public Picnic Parks
Country Clubs, Residents
Country Clubs, Members
Public Institutions
(non-hospital)
Persons
Per Unit
per
per
per
per
per
per
per
per
per
per
per
per
per
per
per
per
per
person
meal
student
student
student
swimmer
stall
seat
employee
passenger
employee
customer
1000# milk
picnicker
resident
member
resident
gal /cap/
day
25
5
15
20
100
10
5
5
15
5
15
2
100-250
5-10
100
50
100
Avg.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
07
02
OU
05
17
03
02
01
05
02
05
01
56
01
17
17
17
With
Garbage
Grinder
_
0.06
0.05
0.06
0.20
-
-
-
-
-
-
-
to 1.66
-
0.25
0.20
0.23
BOD^
(mg/L)
3^0
1*50
320
360
205
360
1*50
250
1*50
1*80
1*50
800
650-2000
250
205
It 00
205
Most of the Water Pollution Control Agencies at the State level have
established recommended and/or required guideline values for -waste-water
loadings from various commercial establishments and public service facilities.
Typically, these state guidelines are limited to daily wastewater flow volumes
but a few also include daily BOD,- and suspended solids contributions and the
flow period. Most states will allow deviations from their adopted guidelines,
if the deviations can be proven accurate. The state guideline values for
wastewater flow volume have been summarized in Table A-Ult.
The State guidelines appear to have been derived from a variety of sources,
including standard textbooks, equipment manufacturers' literature and the
Manual of Septic Tank_Practice (1967). Sometimes information presented in
these sources was reproduced exactly, but more often modifications were made
based upon agency experience. The basis for the design guidelines used by a
representative sample of the states is shown in Table A-it5 •
A-51
-------
TABLE A-HH. SUMMARY OF STATE FLOW
GUIDELINES, gal/unit/day*
Establishment
Bars /Taverns
Bowling Alleys
Picnic Parks (Toilet)
Picnic Parks (Toilet,
Showers)
Campground (Central Bath
House)
Churches (No Kitchen)
(With Kitchens)
Country Clubs
Laundromats
Marinas
Motels
Restaurants , Drive-in
Restaurants
Schools (restrooms only)
(restrooms plus
cafeteria)
(restrooms, cafeteria
and showers)
Service Station
Shopping Centers
Stadia
Theater, Drive-in
Theater
Unit
Seat
Patron Space
Lane
Capita
Capita
Capita
Site
Seat
Seat
Non-Re sident
Member
Resident
Member
Member
Machine
Wash
-
Bed Space
Room
Person
Car Space
Meal or
Patron
Seat
Capita
Capita
Capita
Car
1st Bay
Each Added
Bay
1000 ft^
Seat
Car Space
Seat
No. of
States
12
6
IT
3U
29
28
5
16
9
23
23
13
19
15
_
13
18
11
9
22
19
37
39
39
26
8
8
12
T
Uo
30
Mean
28
5
96
6
12
38
100
It
6
23
98
U8
lH9
^9
—
kk
109
55
1+8
10
38
1U
18
23
10
1000
625
233
3
6
U
Mode
20(8)t
2(3)
75(8)
5(30)
10(2U)
35(18)
—
5(7)
7(6)
25(20)
100(21)
50(9)
Uoo(io)
50(12)
—
1*0(8)
100(12)
50(5)
50(6)
10(8)
35(7)
15(23)
20(18)
25(16)
10(23)
1000(8)
500(6)
100(7)
3(5)
5(29)
5(23)
Range
20-60
2-9
50-200
5-10
10-25
25-50
50-150
.5-5
.8-7.5
15-37.5
75-100
25-100
150-800
UO-50
—
1*0-65
75-200
1*0-100
5-100
3-25
10-70
8-30
8-30
8-35
5-15
1000-1000
500-1000
100-1000
2-5
3-20
2-5
* Liters •= 3.8 x gal.
"f" Number in parenthesis equals the number of states using the value indicated
for the mode.
A-52
-------
TABLE A-45. SOURCE OF DESIGN CHARACTERISTICS
USED BY VARIOUS STATES
State
Source of Design Characteristics
Alabama
Alaska
Arizona
Connecticut
Delaware
Georgia
Idaho
Kentucky
Louisiana
Maine
Massachusetts
Michigan
Minnesota
Missouri
Nebraska
New Hampshire
New Jersey
New York
North Dakota
Ohio
Pennsylvania
Rhode Island
South Carolina
Tennessee
Virginia
Some literature, but mostly meter readings and experience.
Manual of Septic Tank Practice (USPHS, 1967)
Standard texts and catalogs.
Metcalf and Eddy or other standard texts.
Developed own figures from other sources, based on exper-
ience . Have been found very reliable .
Chrysler Corporation Equipment Catalog (based upon
literature).
Manual'of Individual Water Supply Systems (USEPA, 1973)
Jet Aeration Company information.
Equipment manufacturers' catalogs.
Manual of Septic Tank Practice
Flows used by neighboring states, modified when dictated
by meter readings.
Manual of Septic Tank Practice with modifications.
Manual of Septic Tank Practice
Source unknown. Data used is satisfactory.
Davco Manufacturing Company. Data satisfactory.
Federal guidelines and experience.
Standard textbooks.
Source unknown.
Manual of Septic Tank Practice
Jet Aeration Company.
Manual of Septic Tank Practice with modifications.
Manual of Septic Tank Practice with modifications.
Literature review and actual sampling.
Previous literature, meter reading and experience.
Mixture of studies and experiences.
Peak Flow Estimation—
Around 19^0, Hunter developed a procedure for estimating water supply .
demands on plumbing systems (Hunter, 19^0; 19^1). Although originally devel-
oped for peak water demands and sizing distribution systems, it has been used
to predict peak wastewater flows as well (WPCF MOP-9, 1970; IAPMO UPC, 1976).
A discussion of this procedure, commonly referred to as the "Fixture-unit
Method," follows.
The fixture-unit method, as developed, was based on the premise that in
general types of application, a given type of fixture had an average flow rate
and an average frequency and duration of use, which determined the water de-
mand for the fixture. The fixture-unit was arbitrarily set equal to a flow
rate of 7.5 gal/min and various fixtures were assigned a certain number of
fixture units based upon their particular characteristics. Based on probabi-
lity studies Hunter developed relationships between peak water demand and the
number of fixture-units present. The fixture-units assigned to various fix-
tures by Hunter are listed in Table A-k6 with curves relating peak demand to
the total number of fixture-units present shown in Figure A-15.
A-53
-------
TABLE A-U6. FIXTURE-UNIT VALUES FOR VARIOUS FIXTURES
(Hunter,
Fixture or Group
Occupancy
Weight in
Fixture
Type of Supply Control Units
Water closet
Water closet
Pedestal urinal
Stall or wall urinal
Stall or wall urinal
Lavatory
Bathtub
Shower head
Service sink
Kitchen sink
Water closet
Water closet
Lavatory
Bathtub
Shower head
Bathroom group
Bathroom group
Separate shower
Kitchen sink
Laundry trays (l to 3)
Combination fixture
i
Public
Public
Public
Public
Public
Public
Public
Public
Office, etc.
Hotel or
restaurant
Private
Private
Private
Private
Private
Private
Private
Private
Private
Private
Private
Flush valve
Flush tank
Flush valve
Flush valve
Flush tank
Faucet
Faucet
Mixing valve
Faucet
Faucet
Flush valve
Flush tank
Faucet
Faucet
Mixing valve
Flush valve for closet
Flush tank for closet
Mixing valve
Faucet
Faucet
Faucet
10
5
10
5
3
2
1*
k
3
k
6
3
1
2
2
8
6
2
2
3
3
Since its original development, the fixture-unit approach has been accep-
ted and applied on a fairly wide-scale, not only for estimating peak water
supply demands but also for predicting peak sewage flows. Descriptions of
the approach including tables listing fixture-unit values and curves presenting
peak flow versus total fixture units present, have been include-d throughout the
literature (e.g. Manual of Septic Tank Practice, 1967; WPCF MOP-9, 1970;
Salvatto, 1972; IAPMO UPC, 1976)^Although variations exist between the values
presented by various sources, the values presented in Table A-U7 and the rela-
tionships shown in Figure A-l6 appear to be representative.
The fixture-unit approach to estimating peak sewage flows possesses
several potential shortcomings. First, it is based on average fixture charac-
teristics and probability projections relating peak flows to total fixture
units present. Deviations from the average values used in developing the
approach could result in potentially significant variations from the peak
flows predicted (WPCF MOP-9, 1970). For water use, Konen (1976) reports that
in general, the estimated demand is typically Ho$ greater than that actually
experienced. Further, in utilizing this approach, originally developed for
water supply, to estimate peak wastewater flows, certain questionable assump-
tions must be made: (l) most water used exits the building as wastewater,
-------
ouu
400
§300
>»
g200
100
0
^in|Mii
F 1 F
:_ F
r
'tf
^
i 1 1 1 ll 1 1 1
im|iin
3R SYJ
REDOV
OR FLl
.»
/
i iiiinii
""l"Tr
5TEMS
INANT
JSH V/i
/£ F
P
F
T
iiiiinii
1 V
LT
LVES
S*
/^
)R SY
REDON
OR FL
ANKS
1 1 iiim t
'
\^
STEMS
1INANT
.USH
1 1 nil HI
s*
~
'LY "i
1 1 1 1 1 1 1 if
D 1000 2000 3000
FIXTURE UNITS
100
'0 40 80 120 160 200 240
FIXTURE UNITS
Figure A-15- Water supply demand versus fixture units present,
500
400
300
200
100
0
7
*1
0 500 1,000 1,500 2,000 2,500 3,000
NUMBER OF FIXTURE UNITS
Figure A-l6. Peak discharge versus fixture units present (WPCF MOP-9» 1970).
A-55
-------
TABLE A-UT. FIXTURE-UNITS PER FIXTURE
(WPCF MOP-9, 1970)
Fixture-Unit
Value as Load
Fixture Type Factors
1 bathroom group consisting of tank-operated vater closet,
lavatory, and "bathtub or shower stall 6
Bathtub (vith or without overhead shower) 2
Bidet 3
Combination sink-and-tray 3
Combination sink-and-tray with food-disposal unit U
Dental unit or cuspidor 1
Dental lavatory 1
Drinking fountain 1/2
Dishwasher, domestic 2
Floor drains 1
Kitchen sink, domestic 2
Kitchen sink, domestic, with food waste grinder 3
Lavatory 1
Lavatory 2
Lavatory, barber, beauty parlor 2
Lavatory, surgeon's 2
Laundry tray (l or 2 compartments) 2
Shower stall, domestic 2
Showers (group) per head 3
Sinks
Surgeon's 3
Flushing rim (with valve) 8
Service (Trap standard) 3
Service (P trap) 2
Pot, scullery, etc. ^
Urinal, pedestal, syphon jet, blowout 8
Urinal, wall lip ^
Urinal stall, washout ^
Urinal trough (each 2-ft section) 2
Wash sink (circular or multiple) each set of faucets 2
Water closet, tank-operated ^
Water closet, valve-operated 8
(2) the lag time between water use and wastewater production is not great,
and (3) the effects of the water-using fixtures and building drainage systems
do not significantly increase/decrease the sewage flow rate compared to the
predicted water demand rate. Finally, since the approach was developed in
19^0, fixture characteristics and lifestyles have changed significantly and
a re-evaluation of the approach is appropriate. This is particularly true
with regard to estimating peak sewage flows.
A-56
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Individual Establishment Field Monitoring—
Field studies have been conducted on many of the establishments under
study and have generated valuable information on vastevater characteristics.
Unfortunately, the results of many of these studies have not received wide-
spread distribution. In the following discussion, the results of actual field
measurements on each of the establishments under study are presented.
Bars/Taverns—To date, it appears that no specific field studies have
been conducted to determine the characteristics of bar or tavern wastewater.
Several of the general guideline tables do, however, list daily flows and a
few even suggest BOD,- and suspended solids contributions (Tables A-kQ through
A-kh). On a per patron basis, a typical flow is 1.6 L/day (2 gal/day) with a
BOD,- contribution of it.5 g/day (0.01 Ibs/day), while on a per seat basis
the typical flow becomes 76 L/day (20 gal/day).
Bowling alleys—A limited amount of bowling alley water use information
was generated by two studies around I960. The Oakland County Department of
Public Works in Michigan obtained meter readings from the local water depart-
ment concerning each of 4 modest bowling alleys and determined the water use
data shown in Table A-kQ (Shah, 1976).
TABLE A-H8. BOWLING ALLEY WATER USE (Shah, 1976)
Bowling Alley
Description
Dates
L/day/lane
A
B
C
D
17 Lanes
20 Lanes,
Bar, 66 Seats
18 Lanes
12 Lanes
195U1959
1957-1959
1958
1958
200
212
20U
185
The Florida State Board of Health obtained water use information through
monthly metering of a 2k lane bowling alley with restaurant and bar facilities
(Santarone, 1976). The following water use data was generated:
January, I960 - 21,830 L/day/lane
February, I960 - 20,1*90 L/day/lane
March, I960 - 33,990 L/day/lane
April, I960 - 36,930 L/day/lane
Average Day = 950 L/day/lane
Maximum Day = 1230 L/day/lane
Minimum Day = 730 L/day/lane
The average flow of 950 L/day/lane is considerably higher than the 200 L/day/
lane average determined by Oakland County. The higher flow/lane is difficult
to explain without further information, but may be due to the restaurant
facilities provided.
Guideline values for daily flows and BOD,- contributions for bowling
alleys (excluding food service) are typically in the range of 280 to kjO L/
day/lane (75 to 125 gal/day/lane) and 59 to 1^5 g/day/lane (0.13 to 0-32
Ibs/day/lane), respectively.
A-57
-------
Campgrounds and picnic parks — As might be suspected, the United States
Department of Agriculture-Forest Service has information regarding the char-
acteristics of wastewaters produced through picnic and camping related acti-
vities (Kolzow, 1975). Based upon experience and characterization studies
which they have conducted, the Forest Service has suggested system design
loadings for average BOD,- and average flow as shown in Table A-^9. The
results of analyses performed by the Forest Service on vault toilet wastes are
summarized in Table A-50.
TABLE A-U9. SUGGESTED DESIGN LOADINGS - CAMPING FACILITIES
APPLI CATION* (Kolzow, 1975)
Flow
Type of Use L/day/unit g/day/unit
Camper
No Showers Provided 130 ^5
Showers Provided 150 55
Picnicker 19 1^
Swimmer
No Showers Provided 19 1^
Showers Provided 38 18
Picnic and Swim Area
Participant 38 18
Boat Launch Area Participant 19 1^
(Also Fisherman Parking)
* Assumes toilets provided are conventional flush type.
TABLE A-50. VAULT TOILET WASTE ANALYSES (Kolzow, 1975)
Parameter Average Concentrations
(mg/L)
BODc- 19,700
COD 1+0,300
Total Solids UU,700
Dissolved Solids 19,600
Suspended Solids 25,100
General guidelines for campgrounds and picnic parks may be grouped ac-
cording to day-use parks with toilets only, day-use parks with toilets and
showers, and campgrounds with a central bathhouse. For the day-use park pro-
viding only toilet facilities, on a per user basis, the typical flow is 19 L/
day (5 gal/day) with a BOD5 contribution of ^.5 to 13-5 g/day (.01 to 0.03
Ibs/day). If shower facilities are also provided, the typical flow is 38 L/
A-58
-------
day (10 gal/day) with a similar BOD,-. For a developed campground with a
central bathhouse, an average flow of 150 L/camper/day (Uo gal/camper/day)
with a BOD,- contribution of approximately 45.4 g/camper/day (0.1 Ibs/camper/
day) is suggested.
Churches—A field study which provided information concerning church
wastewater was conducted as part of a commercial water use study at Johns
Hopkins University (Wolff, Linaweaver and Geyer, 1966). Quarterly billing
records were obtained for at least a three-year period and recording water
meters were installed for approximately one month at each of two churches.
Annual water use, peak water demands and daily hydrographs were determined.
As shown in Table A-51» the average annual per member usage was 0.52 L/day
(0.14 gal/day) with a range of 0.04 to 0.94 L/day (0.01 to 0.25 gal /day).
Daily water use measurements yielded maximum day and peak hour demands of
3.26 and 17.8 L/member/day (0.86 and 4.7 gal/member/day), respectively.
The daily hydrograph determined for the maximum water use day at one of
the churches illustrates the effect of evening activities on water use
(Figure A-17). Typical patterns of water use during days on which services
alone are held are much lower, and do not reflect the magnitude of hourly use
shown on this hydrograph.
TABLE A-51. CHURCH WATER USE CHARACTERISTICS
(After Wolff, Linaweaver and Geyer, 1966)
Measurement
Parameter
Mean Daily
Minimum Daily
Maximum Daily
Max. Qtr. /Average Annual
Peak Hour
Unit
L/day /member
L/day /member
L/day /member
L/day /member
Annual Use
0.52
0.04
0.94
1.29
Daily Use
0.74
3.26
17.8
The suggested flows for churches are quite consistent around 11 to 19
L/seat/day (3 to 5 gal/seat/day) for churches without kitchen facilities and
19 to 30 L/seat/day (5 to 8 gal/seat/day) for those with kitchen facilities.
For the above, the BOD^ varies from 4.5 to 13-5 g/seat/day (0.01 to 0.03 Ibs/
seat/day). These values appear to be conservative and probably represent
maximum conditions.
Country (golf) clubs—At Johns Hopkins University, the water use charac-
teristics of golf clubs were also investigated (Wolff, Linaweaver and Geyer,
1966). Quarterly billing records were obtained for at least a three-year
period and recording water meters were installed for approximately two weeks
at each of the two country clubs. The mean annual usage per member for the
two clubs studied was 250 L/day (66 gal/day) with a range of l68 to 305 L/day
(44.5 to 80.7 gal/day). In both cases sprinkling demand was not a factor
because sources other than the possible water supply were used. A hydrograph
A-59
-------
5
O
N*
CC
U
CO
|
^
o
o>
O
4 2
2300 MEMBERS
,
IT.
MM 6 U G
TIME OF DAY
MN
Figure A-17-
Daily water use hydrograph for a church
(Wolff, Linaweaver and Geyer, 1966).
for the maximum day recorded at one of the clubs is shown in Figure A-18,
peaks are indicated, one before noon and one between 5 and 6 p.m.
Two
l£
10
>-
<
5 a
cr
LJ
§ 6
UJ
2 A
^^ *T
J
<
<^ 0
2
r>
:i2oo
1MEMBERS
kn
•
r
'U
•
"
-
:
-
^
i-i ~
p
UJ
••
:
MN 6 N 6
TIME OF DAY
MN
Figure A-l8.
Daily water hydrograph for a golf club
(Wolff, Linaweaver and Geyer, 1966).
A-60
-------
Typical guideline estimates for country club vater use/waste production
differentiate between transient members and resident members. The typical
suggested flow is 95 L/day (25 gal/day) per transient member and 380 L/day
(100 gal/day) for a resident member, with a typical BODj- contribution of 32
g/day (0.07 Ib/day) and 90 g/day (0.20 Ib/day), respectively.
Laundromats—Of particular interest are the daily wastewater flow volumes
and usage patterns, as qualitative characteristics may be estimated using the
results presented for household clotheswasher wastewater (Household Wastewater
Characteristics section of this Appendix). Several field studies have been
conducted to determine the quantitative characteristics of laundromat waste-
water. At Manhattan College, while investigating synthetic detergent removal
from laundry wastes, Eckenfelder and Barnhart (1962) obtained operating data
from several laundromats. A typical installation sampled, was found to contain
30 washing machines, each of which used 113 L (30 gal) of water during its
half-hour operating cycle. Under normal operating conditions, the authors
reported there were 50 cycles/week/machine producing a total weekly wastewater
volume of 5670 L (1500 gal).
The Oakland County Department of Public Works, Michigan, obtained water
use data for ten laundromats from approximately one year of quarterly billing
records prior to I960 (Shah, 1976). The information generated is shown in
Table A-52.
TABLE A-52. LAUNDROMAT WATER USE (Shah, 1976)
Laundromat No. of Clotheswashers L/day/Clotheswasher
1
2
3
k
5
6
7
8
9
10
20
20
10
43
39
18
23
32
23
20
990
1150
590
810
560
370
310
690
460
510
Based on the results of the survey, the average water use per washer was cal-
culated to be 61;0 L/day (170 gal/day) with a range of 310 to 1150 L/day (83 to
304 gal/day).
In 1963, Flynn and Andres (19&3) reported the results of research spon-
sored by the New York Water Pollution Control Board investigating the pollu-
tional load of laundromat wastewater. The authors found that the average
wastewater flow per machine varied from 3^0 to 910 L/day (89 to 2kO gal/day),
with the maximum flow for any laundromat studied equal to 2220 L/day (590 gal/
day). The authors concluded that the minimum design flow for a laundromat
should be based upon the manufacturer's stated capacity for the type of washer
A-6l
-------
employed and an assumed 12-hour day with continual operation of all machines.
For a 150 L (Ho gal) washer operating on a *i5-minute cycle, the design flow
would be 2U20 L/day/washer (6UO gal/day/washer).
In the water use studies conducted at Johns Hopkins University (Wolff,
Linaweaver and Geyer, 1966) the water use characteristics of coin-operated
laundromats were investigated. Quarterly billing records of five laundromats
were obtained for at least a three-year period and analyzed. The mean annual
use was found to be 88 L/day per m2 of establishment floor space (2.2 gal/day/
ft2) with a range of 31 to 270 L/day per m2 (0.8 to 6.5 gal/day/ft2). The
upper limit of the 95% confidence interval was 260 L/day per nr (6.U gal/day/
ft ). A recording water meter was installed at one of the five laundromats
to determine a daily hydrograph. As shown in Figure A-19» water usage was
prevalent and relatively constant between T a.m. and U p.m.
0.80
060-
040
S 0.20
3500
0.923
HOUR
RECORDED
MN 6 N 6
TIME OF DAY
MN
Figure A-19-
Daily water use hydrograph for a laundromat
(Wolff, Linaweaver and Geyer, 1966).
Based upon meter readings and extensive experience, the Washington
Suburban Sanitary Commission (WSSC) determined that a typical laundromat can
be expected to use an average of 150 L/day per m2 (3.7 gal/day/ft2) of estab-
lishment floor space (Bishop, 1975).
In Connecticut a laundromat was experiencing considerable difficulty and
flow volumes were measured as part of a compliance order issued by the state
(May, 1975). The average flow measured was 18,900 L/day (5000 gal/day) with
a recorded maximum of 30,2^0 L/day (8000 gal/day). On a per machine basis,
the average flow was about U50 L/day (120 gal/day) with the recorded maximum
equal to 720 L/day (190 gal/day).
To facilitate comparison of the characteristics determined by each of
the previously discussed studies, Table A-53 has been prepared. When the
results of these studies are compared to the values listed in various general
guideline tables, it can be seen that the average guideline estimates for flow
A-62
-------
are somewhat conservative, as they are typically in the range of 1500 to 1900
L/day/machine (1*00 to 500 gal/day/machine).
TABLE A-53. LAUNDROMAT WASTEWATER FLOW COMPARISON
Source
Eckenfelder and Barnhart (1962)
Oakland County Department of
Public Works (Shah, 1976)
Flynn and Andres (19&3)
Johns Hopkins University (Wolff,
Linaweaver and Geyer, 1966)
Washington Suburban Sanitary
Commission (Bishop, 1975)
Connecticut (May, 1975)
Unit
L/machine /week
L/mac nine /day
L/machine /day
L/m^/day
Q
L/m /day
L/machine /day
Mean
5670
61*0
-
88
150
1*50
Range
_
310-1150
31*0-910
2.9-21*. 7
-
? - 720
Marinas—The wastewater generated by a marina complex as a whole has not
been the subject of any field studies to date and guidelines for the category
"marina" are for the most part, non-existent. This is most likely due to the
fact that the term "marina" describes a complex which includes smaller indi-
vidual establishment units, such as a comfort station, restaurant, motel, and
service station, and guidelines and studies (if performed) have been concerned
with these smaller units. Thus, the marina category will not be considered
further in this study. Pumpout wastes from the boats within a marina docking
area are of separate concern and considerable data regarding their character-
istics may be found elsewhere (Clark, 1968; Robbins and Green, 197^; Glueckert
and Saigh, 1975).
Motels—Several investigations have been conducted which have provided
information to estimate the characteristics of motel wastewaters. In I960,
Searcy and Furman (l96l) studied water use by various institutions, including
motels. Monthly rates were obtained from city records for an 18-month period;
daily readings were taken directly from the motel water meters for at least a
two-week period; and hourly readings were taken on several selected days. Six
motels were selected for study. Two had restaurants which were served by
separate meters, another had a coffee shop which served breakfast only, and
three had no restaurant facilities. Based upon the results of the study, the
authors suggested the following design flow rates:
2l*-hour average - 265 L/day/bed space
12-hour maximum - 1*00 L/day/bed space
l*-hour maximum - 660 L/day/bed space
1-hour maximum - 1190 L/day/bed space
The daily flow pattern for a typical motel may be found in Figure A-20.
In 1962, Hubbell reported the results of a water consumption survey of 11
motels containing a total of ll*l* housing units. The average water use was
found to be 350 L/day (92 gal/day) per housing unit. The author noted that in
A-63
-------
>200
^
I150
3'°°
5°
o
20
Z
0- ic
O ID
i
-Z. 10
g '*
0. o
2 8
1 4
« 0
U. (ji
3000o
200i
100
LJ
(E
UJ
O.
MN 6 N 6 MN
TIME OF DAY
ft.
T
1
*•
CM
Figure A-20.
Motel daily water use pattern
(Searcy and Furman, 196l).
many cases, the average included owner use, sprinkling and miscellaneous use.
Allowing for these losses, but compensating for low vacancy periods, Hubbell
recommended a design load of 280 to 380 L/day (75 to 100 gal/day) of domestic
strength wastewater per occupied unit.
As part of the water use studies conducted at Johns Hopkins University in
the early 1960's, motel water use characteristics were determined. As part of
the residential water use study (Linaweaver, Geyer and Wolff, 19&7)> a single
motel was monitored and the following characteristics were measured:
Units
Average Annual Demand
Maximum Recorded Day
Maximum Hour
Peak Hour
- 166
- 260 L/day/unit
- 370 L/day/unit
- 1^90 L/day/unit
— 7 a.m. — 8 a.m.
A typical daily water use hydrograph for the motel studied is shown in Figure
A-21.
Water use data from five motels were collected and analyzed as part of
the Johns Hopkins commercial water use study (Wolff, Linaweaver and Geyer,
1966). Based upon the inspection of three years of quarterly billing records,
the mean annual water use for the motels studied was found to be 9 L/day per m
(0.22 gal/day/ft2) of floor space with a range of usage varying from 6.3 to 11
L/day/m2 (O.l6 to 0.27 gal/day/ft2). Assuming 18 m2 (190 ft ) per housing
unit, these figures would convert to 170, 330 and 580 L/day/unit (U5, 31 and
5^ gal/day/unit), respectively. The maximum demand was found to occur during
the summer quarter, since a number of the motels contained swimming pools.
Nearly all of the motels had restaurants.
Recording water meters were installed at three of the motels for a total
of 117 days (of which UO generated useable data). Recorded maximum daily
A-6U
-------
150
100
50
MN 6 N 6
TIME OF DAY
MN
Figure A-21. Daily vater use pattern for a motel
(Linaweaver, Geyer and Wolff, 1967).
usage was 11.3 L/day/m (0.28 gal/day/ft ). The ratio of the maximum day to
the daily mean was 2.06 with the maximum hour to the mean, 6.92. A daily
hydrograph for one of the motels studied is shown in Figure A-22. Two large
peaks were found to occur, between 8 and 10 a.m. and 8 and 10 p.m. It should
be noted that the motels studied contained facilities (restaurant, bar and/or
swimming pool) whose water use were included in the measured water use rates.
Also, the provision of these types of facilities along with the housing units,
makes the motels studied more sophisticated than those providing only rooms
and vending machines. However, the water use rates may be applicable to
smaller, simpler motels since the total floor area of the motel complex was
used to compute the flow rates.
Several local governmental units have provided additional information on
motel wastewater. The sewer design section of the County Sanitation Districts
of Los Angeles County has developed information on the quantity of sewage
generated by various establishments, including motels (Fuller, 1975). An
average flow of 230 L/customer/day (62 gal/customer/day) with a peak flow of
680 L/customer/day (l8l gal/customer/day) is used by Los Angeles County.
The Washington Suburban Sanitary Commission reported the results of a
motel water use study in 1968 (WSSC, 1968). Water use information was obtained
for ten motels from the Water Registrar for the year, 1967. For six motels
with attached restaurants the average usage per rental unit was found to be
660 L/day (175 gal/day) with a range of 1*50 to 880 L/day (119 to 231* gal/day)
and a median of 680 L/day (l8l gal/day). For four motels without restaurants,
the average usage per rental unit was found to be U80 L/day (128 gal/day),
with a range of ^20 to 550 L/day (ill to 1^5 gal/day) and a median of ^70 L/
day (125 gal/day).
A-65
-------
0.60
0.50
040
^ 0.3C
u.
<0.20
0.10
69,910 FT2
MN 6 N 6 MN
TIME OF DAY
Figure A-22.
Motel water use pattern (Wolff,
Linaweaver and Geyer, 1966).
In 1976, the Oakland County Department of Public Works in Michigan re-
ported the results of a recent study of motel water consumption (Shah, 1976).
Water use records for a 3-year period at 26 motels in Oakland County were
analyzed. It was discovered that motels with less than 50 rooms had water use
characteristics distinctly different from motels with 50 rooms or above. Most
of the motels with 50 rooms or above were found to have restaurants and recre-
ation facilities which contributed to a higher usage. The results of the
study are summarized in Table A-5^.
TABLE A-5^. MOTEL WATER USE (Shah, 1976)
Motel Size
Below 50 rooms
Above 50 rooms
Number of
Motels
13
13
Average No .
of Rooms
28
183
L/ day /room
Average
Uoo
710
Range
72 - 720
360 - 1360
To facilitate comparison of the flow values determined in each study,
Table A-55 has been prepared. Typical guidelines for flow compare reasonably
well with the average values shown in Table A-55, as the recommended flow is
commonly 150 to 190 L/day/bed space (UO to 50 gal/day/bed space) or 380 L/day/
unit (100 gal/day/unit).
A-66
-------
TABLE A-55. MOTEL WASTEWATER FLOW COMPARISON
Study
Flow
Searcy and Furman (l96l)
Hubbell (1962)
Linaweaver, Geyer & Wolff (1967)
Wolff, Linaweaver & Geyer (1966)
County Sanitation Districts of
Los Angeles County (Fuller, 1975)
Washington Suburban Sanitary
Commission (WSSC, 1968)
Oakland County DPW (Shah, 1976)
265 L/day per bed space
350 L/day per housing unit
260 L/day per unit
9 L/day per m^
230 L/day per customer
480 L - 660 L/day per rental unit
kOO L/day per rental unit (< 50 room
motels)
710 L/day per rental unit (> 50 room
motels)
Restaurants—The characteristics of restaurant wastewater have been
Restaurants can be divided
A separate discus-
studied in some detail by various investigators.
into two categories, conventional sit-downs and drive-ins.
sion of each follows.
Searcy and Furman (1961) studied the water use of two restaurants and one
cafeteria. The restaurants were operated in conjunction with motels and the
cafeteria was a part of a shopping center. Three meals per day were served by
the restaurants and two were served by the cafeteria. Based on quarterly
billing records and daily meter readings, the average water use was measured
as 2k to 29 L/meal/day (6.k to 7.7 gal/meal/day). The daily flow pattern for
a typical restaurant is shown in Figure A-23.
14
3 io
I 8
a
J 2
8 0
MN 6 N 6 MN
TIME OF DAY
O.CVJ
Figure A-23. Restaurant daily water use pattern
(Searcy and Furman, 1961).
Based upon the results of their investigation, the authors recommended the
following design flows:
A-67
-------
2 It-hour average - 3^ L/meal/day
12-hour maximum - U8 L/meal/day
U-hour maximum - 58 L/meal/day
1-hour maximum - 68 L/meal/day
Hubbell (1962) reported that a large restaurant in Birmingham, Michigan
employing about 120 and containing 376 seats in a cafeteria and dining room,
had a I960 water consumption of 230 L/seat/working day (6l gal/seat/working
day). This amounted to kk L/meal (11.7 gal/meal). Complete garbage grinding
facilities were used at the restaurant.
The water use characteristics of fourteen restaurants were evaluated at
Johns Hopkins University during the early 1960's (Wolff, Linaweaver and Geyer,
1966). Based upon the inspection of three years of quarterly billing records,
the mean annual water use was found to be 91 L/seat/day (2U.2 gal/seat/day)
with a range of usage varying from 9-5 to 260 L/seat/day (2.5 to 67.9 gal/seat/
day). The upper limit of the 95% confidence interval was 210 L/seat/day
(55.2 gal/seat/day). Use during the maximum quarter was 135 L/seat/day (35-^
gal/seat/day).
A recording water meter was installed at one of the restaurants for a
total of 21 days (11 produced useable data). The average daily use was 230
L/seat/day (6l gal/seat/day). The maximum day during the monitoring amounted
to 320 L/seat/day (83.^ gal/seat/day) with a peak hour of 630 L/seat/day (167
gal/seat/day). A daily hydrograph was developed and is shown in Figure A-2U.
The operation of a typical conventional restaurant was found to closely follow
the water use hydrograph of a residence. A peak was reached in the forenoon,
between 2 and 5 p.m. and between 6 and 8 in the evening. Another peak was
experienced after midnight.
The State of Florida sponsored a water use study which included several
cafeteria restaurants (Santarone, 1976). Monthly water meter readings were
obtained at each of four establishments producing the results shown in Table
A-56.
TABLE A-56. CAFETERIA WATER USE (Santarone, 1976)
L/seat/day
Cafeteria Months of Data Number of Seats Average Range
A
B
C
D
17
23
2U
12
226
200
200
U2U
95
21*0
120
91
15-lHO
150-390
72-160
6U-110
The City of Honolulu obtained composite samples from each of two restau-
rants over a five-day period as a part of a wastewater quality survey
(Hayashida, 1975). The average characteristics determined are shown in Table
A-57.
A-68
-------
150
PEAK HOUR RECORDED
167
feioo
I
<; so
140 SEATS
*
n
MN 6 N 6
TIME OF DAY
MN
Figure A-2k. Restaurant daily water use pattern
(Wolff, Linaweaver and Geyer, 1966)
TABLE A-57. RESTAURANT WASTEWATER CHARACTERISTICS
(Hayashida, 1975)
Parameter
Restaurant #1
Restaurant #2
Average
BOD, mg/L
COD, mg/L
Suspended Solids, mg/L
Grease, mg/L
pH
759
3606
800
663
6.8-8.2
525
1367
202
356
8 . 9-11 . 3
6UO
2500
500
510
-
The County Sanitation District of Los Angeles County uses 31 L/customer/
day (8.1 gal/customer/day) as the average restaurant flow with 6k L/customer/
day (17 gal/customer/day) as the peak flow (Fuller, 1975).
To determine if waste surcharges were necessary, the City of Greensboro,
North Carolina collected samples from each of five restaurants (Shaw, 1970).
Twenty-four hour, flow composited samples were obtained from each facility over
a three-day period and average characteristics were determined. The results
are shown in Table A-58.
The Philadelphia Water Department obtained several twenty-four hour
composite samples from local restaurants and the results of qualitative
analyses yielded the results shown in Table A-59-
A-69
-------
TABLE A-58. RESTAURANT WASTEWATER (Shaw, 1970)
Restaurant
Parameter ABODE Average
BOD, mg/L
Suspended Solids,
mg/L
531
286
390
1*8
1*23
172
651
378
737
1*02
5M5
257
TABLE A-59. RESTAURANT WASTEWATER QUALITY (Kulesza, 1975)
Suspended Solids
y
Restaurant mg/L mg/L
A
A
A
B
C
C
D
D
E
E
960
630
880
280
750
750
6lO
570
680
1*35
ll*28
828
1058
172
1112
81*6
1200
918
1985
728
Average 655 1030
To facilitate comparison of the results of the preceding field studies,
Table A-60 has been prepared vith the average values for several parameters
shown. Most of the general guidelines tables include restaurants, and the
typical flow given is 38 L/patron/day (10 gal/patron/day) with a BOD,- loading
of 9.1 g/patron/day (0.02 Ibs/patron/day) or 250 mg/L. On a per seat basis,
the typical flow is 130 L/day (35 gal/day). When compared to the results of
the field studies shown in Table A-60, the guideline flows appear appropriate
although the estimated BOD,- contribution is somewhat low.
A single study was identified which investigated the water use of drive-
in restaurants, as part of the commercial water use study at Johns Hopkins
University (Wolff, Linaweaver and Geyer, 1966). The authors identified two
types of drive-in restaurants, those with seating facilities and those which
have little or no seating facilities. Based upon quarterly billing records of
a drive-in with little seating, an average water use of 1*10 L/day (109 gal/day)
per car space was identified with the ratio of the maximum quarter to the
average annual use equal to 1.78. The authors recommended an average design
water use of 380 L/day (100 gal/day) per car space for this type of establish-
ment.
A-70
-------
TABLE A-60. RESTAURANT WASTEWATER COMPARISON
Parameter
Study
mg
Suspended
Solids
mg/L
Grease Flow
mg/L L/day per unit
Searcy and Furman (1961)
Hubbell (1962)
Johns Hopkins (Wolff,
Linaweaver and Geyer, 1966)
Florida (Santarone, 1976)
Honolulu, Hawaii
(Hayashida, 1975) 6^0 500
Los Angeles County,
California (May, 1975)
Greensboro, North Carolina
(Shaw, 1970) 5^6 257
Philadelphia, Pennsylvania
(Kulesza, 1975) 655 1030
510
3^ per meal
1*U per meal
91 per seat
91-2^0 per seat
31 per patron
Three typical drive-ins having seating arrangements were also studied.
The mean annual water use was found to be 150 L/day (^1 gal/day) per seat
with a range of usage of ikO to 180 L/day (37-8 to k6.k gal/day). A recording
water meter was installed at one of the drive-ins and a daily water use hydro-
graph was developed as shown in Figure A-25. The hydrograph is for a typical
summer day.
100
50
176 SEATS
PEAK
HOUR
RECORDED
6 N 6
TIME OF DAY
Figure A-25.
Drive-in restaurant water use pattern
(Wolff, Linaweaver and Geyer, 1966).
A-71
-------
Most of the general guidelines do not differentiate "between conventional
sit-down restaurants and drive-ins. Those that do, indicate an average flow
of 7.6 to 15.2 L/patron/day (2 to U gal/patron/day) or 190 L/day/car space
(50 gal /day /car space).
Schools — Considerable effort has been devoted to monitoring the water use
and wastewater production in public and private schools. Wisnieski and Garber
(1953) studied the annual water consumption and student population of several
schools for a five-year period. The results of this study have been summarized
in Table A-6l. The authors noted certain cautions which should be observed
when applying the results of their study. If a school is to be used for numer-
ous evening meetings, special courses and athletic activities, the quantities
must be increased accordingly; several such schools have reported water use
from 76 to 152 L/cap/day (20 to Ud gal /cap/ day ). However, the occasional use
of the school building for PTA meetings, Boy Scout meetings, and dances should
not increase the per capita water use significantly.
TABLE A-6l .
SCHOOL WATER USE - L/cap/day
(Wisnieski and Garber, 1953)
School Type
Grade Schools
Grade Schools
Facilities
Provided
No Cafeteria
or Showers
Cafeterias
No. of
Schools
31
10
Mean
23
23
Range
9.1 - 55
9.8 - U2
90$
Probability
39
Uo
Junior High
Schools
High Schools
With or Without
Cafeteria and l6
Showers
With Cafeteria
and Showers 30
21 8.7 -
9.8 - 79
37
59
In planning waste disposal facilities for two existing schools, Coberly
(1957) measured the sewage flows to obtain reliable data. A grade school and
combination junior and senior high school were monitored. The grade school
had U37 pupils and the following facilities: 13 toilets, 3 urinals, 2 service
sinks, 1 dishwasher, 1 kitchen sink, 1 garbage grinder, 2 wash fountains, 10
drinking fountains and 13 classrooms. Metered water use over a two-month
Fall period indicated an average use of 21 L/pupil/school day (5.6 gal/pupil/
school day). The average daily sewage flow was measured as 17 L/pupil/school
day (k.k gal/pupil/school day) or approximately 80% of the water used. The
flow occurred between 7'-30 a.m. and 5:30 p.m. with minor flows after those
hours. Peak flows occurred at recess time (10 - 10:30 a.m.), noon and 2 p.m.
The junior and senior high school was served by a sewer line which also
served a greenhouse, one residence and a fire station. Making allowances for
these, the authors determined an average flow of 21,000 L/day (55^9 gal/day)
with an attendance of 1^30 pupils, which represented 15 L/pupil/school day
(3.9 gal/pupil/school day). A broad peak was found to occur about 5:30 p.m.
and was probably due to showering after athletic activities.
A-72
-------
Searcy and Furman (l96l) studied school water consumption extensively at
nine elementary schools, two junior high schools, two senior high schools and
one combined school (kindergarten through twelfth grade). Monthly water use
rates were obtained from city records for an 18-month period; daily readings
were taken directly from the school water meters for at least a two-week
period; and hourly readings were taken on several selected days. All elemen-
tary schools were equipped with cafeterias while the junior and senior high
schools and the combined school included a cafeteria and a gymnasium with
showers. Although water use was determined per pupil per day, the authors
observed that there was not always a direct relationship between water use and
students in attendance. Variations in water use appeared to be more nearly
related to special activities at the school. Nevertheless, since the number
of students did indicate school size, it was used as the basis for expressing
water use.
The average daily water use determined, based upon daily and monthly
meter readings is shown in Table A-62. The daily hydrographs developed for
each type of school based on hourly meter readings are presented in Figure
A-26. It was noted that over 82$ of the water used each day was consumed in
a 10-ll* hour period. In the elementary and junior high schools, 93% of the
total daily flow occurred within a 10-hour period. The effect of showers
following the sports program explained the second peak in the consumption
pattern of the high schools and the combined schools.
TABLE A-62. SCHOOL WATER USE, L/cap/day
(Searcy and Furman, 196l)
Daily Readings Monthly Records
Type of School Mean Range Mean Range
Average Elementary
Average Junior
Average Senior
Combined
High
High
28
25
75
51
21
15
3>*
1*6
- ho
- U6
- 230
- 56
22
23
UU
1*5
0.8
0.1*
1.5
7.2
- U9
- 61
- ll*0
- 70
Based on a review of all data collected during their study, the investigators
recommended the design flows presented in Table A-63.
TABLE A-63. SCHOOL WATER USE, L/student/day
(Searcy and Furman, 196l)
Suggested Design Flows
Type of School
Elementary
Junior High
Senior High
Combined
2 It-Hour
Average
38
1*5
76
53
12-Hour
Maximum
76
91
130
93
It-Hour
Maximum
150
180
190
130
1-Hour
Maximum
190
230
250
170
A-73
-------
ELEMENTARY
I40
i30:
12°-
10
0
en
e>
MN 6 N 6
TIME OF DAY
JUNIOR HIGH
6 N 6 MN
TIME OF DAY
1
UJ
Q
(0
36
30
24
18
12
6
SENIOR HIGH
MN 6 N 6 MN
TIME OF DAY
UJ
Q
50
40
30
20
COMBINED
I0h
0
MN 6 N 6 MN
TIME OF DAY
Figure A-26.
School water use hydrographs
(Searcy and Furman, 1961).
Hubbell (1962) reported that day schools without shower or cafeteria
facilities generally produce a daily per capita load of 38 L (10 gal) and
13-5 g (0.03 Ibs) of BODc, primarily from toilet wastes. Shower and cafeteria
facilities were cited as potentially adding an additional 38 L (10 gal) and
9 g (0.02 Ibs) of BODj. to the above values.
Reeder and Fogarty (196*0 actually metered sewage output from schools
while simultaneously recording the water use at 19 schools in Bade County,
Florida. All schools were serviced by cafeterias while only six had gymnasiums
and shower facilities. Thirteen elementary and junior high schools without
showers had between 277 and 1269 pupils while six junior and senior high
schools with showers had between 830 and 26^5 pupils. Five days of water use
and sewage flow data were recorded simultaneously at each school. During each
measurement period, the custodial personnel were instructed not to water lawns,
wash windows or otherwise use water that would not be returned as wastewater.
The average and various maximum rates of flow determined in this study are
presented in Table A-6U.
As part of the commercial water use study at Johns Hopkins University,
the water use characteristics of elementary, junior and senior high schools in
the public and private categories were determined (Wolff, Linaweaver and Geyer,
-------
TABLE A-6k.
SCHOOL WATER USE AND WASTEWATER FLOWS, L/cap/day
(after Reeder and Fogarty,
Schools With
Restrooms &
Cafeterias
Schools With
Restrooms, Cafeteria
& Showers
Parameter
No. of Schools
Days of Data
Mean of all Days
S.D. of all Days
Mean of Max. Days at all Schools
Maximum Day Observed
Mean of School with Max. Day
Mean of 5-hour Max. at all Schools
Water
13
57
28
5.2
31
kk
36
-
Sewage
13
57
26
5.2
28
39
37
106
Water
6
28
32
5.7
36
50
U2
-
Sewage
6
28
30
5.7
31
k6
36
100
1966). Quarterly billing records were obtained for at least a three-year
period and recording water meters were installed at several schools. The
characteristics determined are shown in Table A-65.
TABLE A-65.
WATER USE IN SCHOOLS - L/student/day
(Wolff, Linaweaver and Geyer, 1966)
Annual Records*
School Type
Public
Elementary
Junior High
Senior High
Private
Elementary
Senior High
Combined (1-12)
No. of
Schools
9
3
7
5
U
5
Mean
20
21
25
8.6
39
32
Range
15 -
10 -
8.1 -
1.5 -
21 -
7.U -
37
36
1*0
19
55
6k
U.L.
95$ C.I.
33
37
1*6
23
70
70
Daily Metering
Mean
ll*
-
20
11
5fc
32
Max.
Day
26
-
57
12
59
61*
Peak
Hour
130
-
350
97
150
190
* School year.
Graphs of daily water use patterns over an entire week are shown in
Figure A-27 for an elementary school and a senior high school. The hydro-
graphs indicate the greater magnitude of demands in the high school. As
shown in the figure, the elementary school exhibits a decided peak at noon,
A-75
-------
ELEMENTARY SCHOOL
925 STUDENTS
O O Q
O CO CO
z
? 8 °"
(0 (O
c
o
o
(U
w
§
vo
ON
H
d
-P
s
0 §
OJ
O 08
c S
C C
H
O O
!>> H
H O
M O
0 ,C
0 O
> to
t-
CM
4:
bO
•H
SO Q
(0 V*
o 02
CM
Ava/iN3anis/nv9
Ava/iN3anis/iv9
A-76
-------
while the high school experiences a decided double peak, one at or before noon
and one late in the afternoon. The latter peak is substantially higher than
the noon peak. The investigators noted that it was due to the athletic acti-
vities which are offered in high school but not in elementary schools.
The Oakland County (Michigan) Department of Public Works investigated the
water consumption of 33 schools for two years (Ringler, 1975). The consump-
tion rates shown in Table A-66 were determined.
TABLE A-66. SCHOOL WATER USE, L/student/day
(Ringler, 1975)
Type of School
No. of Schools
Mean
S.D.
Range
Elementary
Secondary /Other
7
26
33
31
22
21*
10 - lh
5-7 - 130
The Iowa State Health Department analyzed the water use by several Des
Moines schools utilizing records from the Des Moines School Administration
office and the Des Moines Water Works (Evans, 1976). The average per capita
use per school day determined for four types of schools is shown in Table A-67.
TABLE A-67. AVERAGE SCHOOL WATER USE
(Evans, 1976)
Type of
School
Grade
School
Grade
School
Junior High
School
Senior High
School
Facilities
Provided
No Hot Lunch
No Showers
Hot Lunch
No Showers
Hot Lunch
Showers
Hot Lunch
Showers
Swimming Pools
No. of Average
Schools Enrollment
9 IKJO
5 500
3 716
1* 1680
L/student/day
Average
19
25
52
6l
Range
12 - 28
9.1 - Ul
51 - 53
51* - 68
To facilitate comparison of the flow information determined in each study,
the average flows determined by each are listed in Table A-68. As shown, there
is fair agreement in the results of the individual studies.
Most of the general guidelines include three classes of schools, based on
the facilities provided; (l) schools with restrooms only, (2) schools with
restrooms and cafeteria, and (3) schools with restrooms, cafeteria and showers.
A-77
-------
TABLE A-68. AVERAGE SCHOOL WASTEWATER FLOW COMPARISON,
L/student/day
Elementary
Study School
Wisnieski and Garber (1953)
Coberly (1957)
Searcy and Furman (l96l)
Reeder and Fogarty (196*0
Johns Hopkins University (Wolff,
Linaweaver and Geyer, 1966)
Oakland County, Michigan
(Ringler, 1976)
Iowa (Evans, 1976)
23
17
38.
28
1U
33
19
Junior High
School
21
15
1+5
28
-
31
52
Senior High
School
3U
-
76
32
20
31
6l
The suggested flows for these three classes are typically 57, 76 and 9^ L/
student/day (15, 20 and 25 gal/student/day), respectively. When compared to
the results of the individual studies, these guideline flows are very conser-
vative for average flows and even somewhat conservative for peak flows.
Service stations—As a part of a residential water use study, a single
service station was monitored by Linaweaver, Geyer & Wolff (1967), and the
following water use characteristics were measured:
Lifts - 1
Average Annual Flow - 1780 L/day
Maximum Day - 6620 L/day
Maximum Hour - U7»250 L/day (6 p.m.-7 p.m.)
As part of the commercial water study at Johns Hopkins University, water
use data were obtained from 6 service stations (Wolff, Linaweaver and Geyer,
1966). All six had a small office and an attached garage, having one or two
car lifts, and storage space for 2 or 3 cars. Based upon the inspection of
three years of quarterly billing records, the mean annual water use was found
to be 10.2 L/day/m2 (0.25 gal/day/ft ) of combined garage and office floor2
space. The range of usage was 6.5 to 18 L/day/m (0.16 to O.UU gal/day/ft ),
with the maximum usage occurring during the summer.
Recording water meters were installed at three of the service stations
for a total of 65 days (31 produced useable data). The mean daily usage
measured was 7.2 L/day/m (O.l8 gal/day/ft ). The maximum day recorded was
17 L/day/m (O.Ul gal/day/ft2), while the peak hour was lUO L/day/nr (3.U gal/
day/ft ). A daily hydrograph was determined for one of the service stations
and indicated a peak usage during the early afternoon hours (Figure A-28).
General guideline estimates for service station flows are typically ex-
pressed in terms of vehicles served or the number of pump islands or service
bays. Suggested flows are 38 L/day (10 gal/day) per vehicle served or 1900
to 3800 L/day (500 to 1000 gal/day) per island or bay present.
A-78
-------
4.0
3.0
-g 2-0
^
CO
O)
1.0
AREA =
2100ft
Ol—
MN
6 N 6
Time of Day
MN
Figure A-28.
Service station water use pattern
(Wolff, Linaweaver and Geyer, 1966).
Shopping centers—A survey conducted in 196l, revealed information on
the vater use characteristics of shopping centers (Anonymous, 196l). In
one study, monthly meter readings on each business establishment within six
shopping centers in the Miami area were obtained. The average consumption
varied from 5.82 to 8.5^ L/day per m2 of store floor space (0.1*13 to 0.210
gal/day/ft ), while the maximum monthly consumption values ranged from 1.16 to
12.45 L/day/m (0.176 to 0.306 gal/day/ft2). The data compiled was graphically
presented as shown in Figure A-29. In a second study, three shopping centers
near Springfield, Massachusetts were metered for one year yielding the follow-
ing water use values:
Shopping center A (1^90 m_)
Shopping center B (kk60 m )
Shopping center C (21,300 m2)
91 L/day/m2
1.26 L/day/m^
2.97 L/day An
The high usage in shopping center A was caused by a laundromat. It should be
noted that the shopping centers studied in the Miama area did not contain
laundromats.
Searcy and Furman (1961) studied water use at a single shopping center.
Monthly rates were obtained from city records for an 18-month period; daily
readings were taken directly from the component establishment water meters
for at least a two-week period; and hourly readings were taken on several
selected days. The results of the study are shown in Table A-69 and Figure
A-30.
A-79
-------
CM
O
o
O
500
400
~ 300
2
cc
it! 200
100
WITHOUT
CAFETERIA
I
! ESTIMATED
U- DIRECTION OF
CURVE WHEN
CENTER "A
REACHES MAX-
IMUM DEVELOP-"
MENT
WITH
CAFETERIA
I
I
0.10 0.20 0.30
WATER USE, GAL/DAY/FT
0.40
2
Figure A-29. Shopping center water use
(Anonymous, 19^1).
TABLE A-69. SHOPPING CENTER WATER USE, L/day/m2
(Searcy and Furman, 196l)
Measurement Period
Average
Range
Monthly Readings
Daily Readings
Hourly Readings
8.50 5.29 - 11.3
7.12 3.31* - 8.83
8.83 ? - 18.3
A-80
-------
0.50
"MN 6 N 6 MN
TIME OF DAY
Figure A-30.
Water consumption pattern of a shopping center
(Searcy and Furman, 196l).
Based upon the results of the study, the investigators recommended the fol-
lowing design flows:
2^-Hour Average
12-Hour Maximum
l|-Hour Maximum
1-Hour Maximum
-10.2 L/day/m;
-15.3 L/day/m J;
-19.3 L/day/nu
- 21.h L/day/m
Hubbell (1962) reported that large shopping centers usually contain a
department store and a variety of smaller establishments and employ from 80 to
ihO equivalent 8-hour employees per acre of building area. Restaurants,
supermarkets, laundromats and car washes are usually among the primary sources
of wastewater, while most other establishments contribute nominal amounts of
wastewater, primarily from employee and public restrooms. Average water use
and estimated wastewater production from three large shopping centers in the
Detroit area as reported by Hubbell are presented in Table A-70.
TABLE A-70. SHOPPING CENTER WATER USE AND WASTEWATER
PRODUCTION (Hubbell, 1962)
Shopping
Center
A
B
C
No. of
Employees
1500
U500
Uoo
Building
Area
(m2)
58,300
116,200
98,1*00
Water
Use
L/day/nr
6.51
10.8
10.7
Wastewater
Produced
L/day/m2
5.37
8.87
8.79
A-8l
-------
A water use survey at Center A on a typical Saturday indicated the following
ratios between the average water consumption rate and the rate during the
indicated period:
Measurement
Period
Measurement Period Rate
2l|-Hour Average Rate
15 Minute
1 Hour
6 Hour
2.5U
2.03
1.83
Investigators at Johns Hopkins University studied the water use charac-
teristics of two shopping centers and their component stores producing the
results shown in Table A-71 (Linaweaver, Geyer and Wolff, 1967).
TABLE A-71. SHOPPING CENTER WATER USE, L/day/m2
(Linaweaver, Geyer and Wolff, 1967)
Shopping Building Mean
Center Area Annual Use
A 22,300 m2 6.02
B 13,500 m2 7-28
Maximum
Day Maximum Hour
8.^6 15.3
(2 p.m. - 3 p.m.)
A daily hydrograph developed for a typical day at Center A is shown in Figure
A-31.
fl
6 N 6
Time of Day
Figure A-31.
Daily water use pattern for a shopping center
(Linaweaver, Geyer and Wolff, 1967).
A-82
-------
A second water use study vas conducted at Johns Hopkins University and
data for five large department stores were analyzed (Wolff, Linaweaver and
Geyer, 1966). Department stores are often the major component of a shopping
center and therefore, merit discussion. Based on the inspection of three
years of quarterly billing records, the mean annual water use was 8.79 L/day
per m of total sales area (0.216 gal/day/ft2) with a range of ^.^7 to 16.4
L/day/m2 (0.11 to O.UO gal/day/ft2).
Recording water meters were installed at two of the stores for a total of
110 days (U2 produced useable data). Recorded maximum daily usage was 15.8
L/day/m2 (0.388 gal/day/ft2) and the peak hour was Uo.O L/day/m2 (0.958 gal/
day/ft2). Hydrographs were developed as shown in Figure A-32 for each of two
large department stores. The mean annual water usage of 1.75 L/day/m (0.0^3
gal/day/ft2) for Store A compared to 7.81 L/day/m2 (0.192 gal/day/ft2) for
Store B reflects the diverse characteristics of the two establishments. Store
A was a typical discount store offering minimal water using facilities, while
Store B was a well appointed department store, offering a restaurant, large
restrooms and other facilities.
"
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0
W
STORE A
- AREA= 182,00
_^
Oft
,
N 6 N 6 M
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
STORE B I
AREA = 118,000 ft
0
MN
f
N
MN
Time of Day
Time of Day
Figure A-32.
Daily water use patterns for department stores
(Wolff, Linaweaver and Geyer, 1966).
A-83
-------
In 197^» Peherty reported the findings of recent studies on several shop-
ping centers of varying size. The average daily water use related to total
floor area for a number of shopping centers in Ontario is shown in Table A-72.
TABLE A-J2. SHOPPING CENTER WATER USE,
L/day/m (Feherty, 197*0
Shopping Center Floor Area (m^) Mean Water Use
A
B
C
D
E
F
G
H
I
J
K
3,900
20,900
7,^00
52,000
109,^00
7^,300
39,000
UU.800
lj.,700
lU,900
10,700
21.6
11.0
11.0
8.13
8.13
7.32
H.UT
U.UT
3.25
2.03
1.63
Average 3^,700 7-55
The City of Honolulu obtained composite samples from a local shopping
center over a five-day period during the summer as part of a wastewater quality
survey (Hayashida, 1975). The following average characteristics were deter-
mined:
BOD - 270 mg/L
COD - 131*1* mg/L
Suspended Solids - 337 mg/L
Grease - 67 mg/L
pH - 7.2-7.8
In 1975, the results of a study to develop methods for forecasting water
use by department stores and commercial establishments commonly located in
suburban shopping centers was reported (McCuen, Sutherland and Kim, 1975).
Water use data was obtained for commercial establishments in four shopping
centers, one in Wisconsin, one in Maryland and two near Washington, D.C.
Water-use data was gathered from two department stores with restaurants, five
department stores without restaurants, and lUo mall shops (falling into 2\
categories). It was noted that air conditioner water use was not included in
the data. Water use relationships were subsequently derived using the data
from these establishments. The authors felt that department store water use
was the result of activities of employees as well as customers. After con-
sidering a variety of proxy variables felt to be indicative of water use, the
authors concluded that the gross store area was the most useful parameter.
The water use data gathered for the department stores is shown in Table A-73-
The data for the department stores without restaurants was analyzed using
linear regression yielding the following water use relationship:
A-8U
-------
Water Use, L/day = -5866 + 2.260 [Gross store area in m2]
(3)
This equation provided a correlation coefficient of 0.92 and a standard error
or estimate equal to 57^5 L/day, significantly less than the 12,320 L/day
standard deviation for the water use data. Due to the insufficient data for
department stores with restaurants, a similar analysis was not performed on
that category.
TABLE A-73. DEPARTMENT STORE WATER USE
(McCuen, Sutherland and Kim, 1975)
Parameter
Stores Without
Restaurants
Stores With
Restaurants
Number of Stores
Water Use, L/day
Mean
Standard Deviation
Range
2
Gross Store Area, m
Mean
Standard Deviation
Range
Mean Water Use/Store Area
L/day/m^
5
12320
6890 - 71180
13550
U990
8180 - 20330
1.83
U5960
3^810 - 57120
15710
1U780 - 16080
2.93
McCuen et al. found water use in mall shops to be considerably less than
that of department stores, primarily due to the fact that the shop restroom
facilities were usually not available to the customer, as they are in depart-
ment stores. Based on the analysis of mall shop water use for those shops
that had at least 100 working days of data, the mean water use was determined
for each of 2U mall shop classifications as presented in Table A-jh. As
shown, a significant amount of variation was found within and between classi-
fications . The authors further analyzed the data using linear regression
techniques and found the following type of relationship most useful and
predictive of water use,
where, W = i + SA
W = Water Use, L/day
i = Intercept in L/working day
S = Coefficient expressed in L/working day/m
A = Gross store area, m
(10
The values determined for i and S for those classifications with sample sizes
of four or more are shown in Table A-75- The expression and values determined
appear valid based on the high correlation coefficients.
A-85
-------
TABLE A-7k.
SHOPPING CENTER COMPONENT STORE WATER USE
(McCuen, Sutherland and Kim, 1975)
Range of
No. of Mean S.D. StorepArea
Type of Store Store (L/day) (L/d) (m )
Healthfood
Mens Clothing
Womens Clothing
Hosiery
Shoes
Wigs
Uni forms
Carpets
Cutlery
Appliances
Music
Sporting Goods
Books
Jewelry
Toys
Cameras
Gifts
Fabric
Art Supplies
Cosmetics
Art Gallery
Bath Goods
Gourmet Food
Opticians
TABLE A-75.
1
20
32
1
28
2
2
2
1
1*
1*
1
3
7
3
2
12
7
2
1
1
1
1
2
SHOPPING
135
1*83
288
581*
256
21*6
399
ll*l*
102
6l8
lH5
218
192
3l*0
233
196
182
1*1*3
11*7
129
108
2l*l
557
_
^99
20k
-
138
59
359
15.
—
808
231
—
36.
ll*l*
ioi*
82
75
181
63
—
-
-
_
111*
86-1670
7^-985
111*
588-5860
1020-2560
70-1^1
8 105-281
98
187-2U80
1020-3720
1*96
o 319-602
1130-3530
106-1*90
67-131
539-21*00
1900-6510
13U-293
1*8
351
355
3l*l*
15l* 71 71-122
Mean
( L/day /m2)
11.9
9.1
10.5
51.3
11.1
31*. 5
33.1*
9.8
10. u
7.2
15.1*
l*.l*
U.8
20.5
8.5
19-9
8.8
7.2
7.1
26.7
3.1
6.8
16.2
15.6
S.D.
( L/day /in )
_
3.2
5.9
_
6.5
3.7
17-8
7-2
_
0.6l
2.5
_
1.8
10.6
2.S
1.0
3.6
1.5
0.8
-
-
-
—
1.5
CENTER COMPONENT STORE WATER USE RELATIONSHIP
PARAMETERS (McCuen,
Type of Store
Mens Clothing
Womens Clothing
Shoes
Appliances
Music
Jewelry
Gifts
Fabrics
No. of
Stores
20
32
28
1*
1*
7
12
7
i
(L/working
-19.0
12 1*. 9
92.9
-ll*.6
-26.3
166.1
80.6
83.6
Sutherland and
Kim, 1975)
S
day) (L/working day/m )
0
0
0
0
1
0
0
0
.927
.1*51
.610
.7^0
.672
.879
.1*60
.569
Correlation
Coefficient
0.798
0.631*
0.707
0.999
0.967
0.777
0.1*77
0.93U
To facilitate comparison of the information gathered concerning shopping
center flows, the average results of each study have been listed in Table A-76.
A-86
-------
TABLE A-76. SHOPPING CENTER PLOW COMPARISON
Study
Anonymous (1961)
Searcy and Furman (1961)
Hubbell (1962)
Linaveaver, Geyer and Wolff (1967)
Peherty (197*0
McCuen, Sutherland and Kim (1975)
1-3
L/day/m
8.13
8.13
7.73
6.67
7.55
1.83 - 2.93
As shown in Table A-76, there is surprisingly good agreement between the
average results determined in the various studies. The flow estimates pre-
sented in the general guideline tables are somewhat lower, typically equal to
IK07 L/day/m2 (0.10 gal/day/ft2).
Sports Facilities—A study investigating the wastewater flow generated by
persons attending sports events was conducted by Pearson and Nesbitt (1975) at
the Pennsylvania State University football stadium. Between 1968 and 1973,
flow records were obtained at 15-minute intervals for 19 days on which football
games were played. Game attendance on these days ranged from 38,600 to 59,980
with a mean of 51,3^0. The following flows were determined:
Average Quantity = ^.5 L/spectator
Standard Deviation = 6.h L/spectator
Mean Peak Flow = 3^ L/spectator/day (l hour)
= 60 L/spectator/day (15 min.)
Peak Flow Standard Deviation = 7.6 L/spectator/day (15 min.)
The guideline tables include estimated flows from spectators at sports
events and festivals typically equal to 3.8 to 19 L/spectator/day.
Theaters—Information on the water use and wastewater production at movie
theaters (both auditorium and drive-in types) has been produced by the Oakland
County Department of Public Works, Michigan (Ringler, 1975). Water use was
monitored at both types of theaters for two years, producing the results shown
in Table A-77. The average flow per seat from an auditorium type theater with
air conditioning was found to be 2.7 gallons and the average flow per car
space from a drive-in theater was found to be 5.0 gallons (both are based on
an assumed 8-hour operating day).
Suggested design flows for theaters are typically 11.3 to 18.9 L/day
(3 to 5 gal/day) per seat or car space.
A-8?
-------
TABLE A-TT- THEATER WATER CONSUMPTION (Ringler, 1975)
Type of Theater
Auditorium Drive-in
Parameter (L/seat/hr of oper.) (L/car space/hr of oper.)
Number of Theaters 13 U
Average Flow 1.28 2.31*
Standard Deviation 1.17 1-7^
Range 0.33 - 3.90 0.71 - U.12
Discussion—
Predicting wastewater loadings for commercial establishments and public
service facilities is a very complex task due to several factors;
1. There are a relatively large number of diverse categories, for vhich
wastewater characterization data may be desired.
2. The inclusion of potentially diverse establishments within the same
category (such as bars) produces a potential for large variations in
waste generating sources, which could yield highly variable waste
loadings. To avoid this problem, subcategories and classes of a
general category should be utilized to aid predictability. However,
this increases the number of groups of establishments to be con-
sidered. Further, many intangible influences such as location,
popularity and price may result in wastewater variations between two
otherwise similar establishments.
3. There is considerable difficulty in presenting characterization data
in a readily applicable, but predictively accurate manner. The most
readily applicable basis for predicting wastewater loadings, such as
an easily identifiable physical parameter, may unfortunately not be
predictively accurate.
In order to assess the sufficiency of the existing characterization data
and to aid in determining the type of additional studies needed, a basis for
assessment is required. In the context of this study it was assumed that to
be considered "sufficient" the characterization data should provide an esti-
mate of design loadings for small wastewater treatment and disposal facilities
for the types of establishments under study. Although a wide variety of pollu-
tant parameters are of interest, the following priority list of those parame-
ters most often utilized in facilities design, was judged to be appropriate:
-------
Priority Parameters
1 - Average Daily Flov
2 - Daily Flow Variation (Peak Daily Flow)
3 - Hourly Flow Variation
k - Average BOD5 or COD
5 - Average Suspended Solids
6 - Average Nitrogen and Phosphorus
7 - Wastewater Quality Variations
In terms of these seven parameter groupings, sufficiency can be viewed as a
matter of degree, varying from no data available to information available for
all the listed parameters, for each establishment under study.
In addition to simply having data available for the various parameters
and establishment categories, it is important that the data were generated and
presented in a predictively accurate and useful manner. Even if a given set
of data is complete and accurate for the establishments at which it was gene-
rated, if the data cannot be employed to yield a reasonably accurate estimate
of wastewater loadings at other, categorically similar establishments, the
data is of marginal utility as a predictive tool.
A review of the existing characterization information readily indicates
the type and extent of the data available for the establishment categories
under study. The general guideline tables present lengthy lists of establish-
ments which are often divided into sub-categories to avoid the diversity of
establishments possible within descriptively, broad classifications such as
schools, restaurants and theaters. In these tables design estimates are
given for daily waste flow volume, and occasionally duration of flow, BOD^ and
suspended solids. The data are typically expressed as a function of some form
of patronage or a physical characteristic of the establishment.
Unfortunately, the primary source of much of the guideline data is
generally obscure or even unknown altogether. In many cases, a given guide-
line table has been reproduced, possibly with minor modifications, from one
source to another, to another, etcetera. In each transfer, any documentation
which may have accompanied the original data is diminished. Even when the
original source of data was identified, attempts to determine the data genera-
tion methods were usually futile due to a lack of initial documentation or
loss of documentation with time. Thus, any assessment of the reliability of
this guideline information for predictive use is difficult, necessarily based
on its "reasonableness" and individual statements concerning its "suitability."
On the one hand, many regulatory individuals claimed the guideline tables
they were employing had proven very satisfactory while on the other hand,
accompanying many of the guideline tables were statements encouraging the use
of actual monitoring of a similar establishment in preference to the guideline
data.
As noted, general guideline information has generally been expressed as
a function of some parameter related to patronage or a physical characteristic
of the establishment. Examples of each include per meal served for restaurants
and per alley for bowling alleys. At first glance, it would seem that a
A-89
-------
parameter related to patronage "would be more accurate from a predictive stand-
point than a physical characteristic. However, the application of data ex-
pressed as a function of patronage is often difficult since an estimate of
patronage is required.
The individual establishment field studies have provided a variety of
data for the categories under study through methods varying from the review of
water utility records to in situ wastewater monitoring. Certain establishments
have received considerable attention while others have received little. The
availability of data for selected parameters and establishment categories
varies considerably depending upon the parameter and establishment of interest.
In general, even without consideration for methods or data presentation, there
is a lack of data for many establishment categories. Further, the reliability
of the available data is often questionable due to the manner in which the
data was generated. For example, one or two daily composite samples of the
wastewaters produced by a single establishment is of questionable predictive
accuracy. At best, this type of data should serve only as a rough guideline.
As indicated by the summary of the existing information and the preceding
discussion, a varying amount of characterization data is available for the
commercial establishments and public service facilities selected for study.
Depending on the parameter and establishment category of interest, the extent
of the data base varies considerably. To a greater or lesser degree, however,
it appears that further characterization studies are necessary for almost all
of the establishment categories under study. Before proposing the form and
extent of any studies, however, it was deemed necessary to review and consider
the overall problem itself, namely, the characterization of wastewater loadings
from commercial and public service establishments. More specifically, the
methods used to generate and present characterization data had to be considered
in the context of their providing useful estimates of the wastewater loadings
from categorically similar establishments.
Analysis of Characterization Approaches
The generation and presentation of characterization data in a predictively
useful and accurate manner is of prime concern. Even when a given set of data
accurately represents the wastewater loadings for the establishment(s) at
which it was generated, if the data is presented in such a way as to make it
very difficult to apply to a categorically similar establishment, it is of
marginal utility. With this in mind, this section is devoted to an evaluation
of various approaches for generating and presenting characterization data.
At most any establishment or facility serving a transient population,
there appear to be two major collective factors which contribute to the water
use and waste production: (l) basic operation and employee personal activi-
ties and (2) direct or indirect contributions related to the patrons served.
At any given establishment, a certain minimum of water-using and waste pro-
ducing activities occur as a matter of basic operational routine. In addition
to this contribution, and most likely the major of the two, is that waste
contribution which results from the presence and activities of establishment
patrons. Included are indirect as well as direct contributions. Indirect
contributions stem from activities performed by the employees for the patron,
A-90
-------
such as food preparation, while direct contributions are the result of patron
activities, such as restroom use. Further, due to variations in patronage
throughout the day, week, and year, it would seem reasonable to expect con-
comitant variations in the water used and wastewater generated.
Of interest then, is a rational approach to take into account these
factors and provide reasonable estimates of the expected wastewater loadings
from the types of establishments under study. In an attempt to identify such
a rational approach, an analysis of various approaches for generating and
presenting characterization data for establishments serving a transient popu-
lation was conducted.
Daily Quantitative and Qualitative Characteristics —
An accurate estimate of average and peak daily flow volumes would seem to
be of highest utility in facilities design compared to the other parameters of
interest. Also of interest are the average and peak daily contributions of
selected chemical/physical parameters, such as BOD,-, suspended solids, nitro-
gen and phosphorus. In the following section, a detailed approach for esti-
mating these parameter loadings will be presented first, followed by increas-
ingly simpler approaches .
Approach 1 — A variety of water using events within a given establishment
commonly occur and result in the production of wastewater. A detailed approach
to predicting wastewater loadings would involve delineating the characteristics
of the wastewater produced by the component events which occur within the type
of establishment under study. For each establishment category, the following
type of prediction equation would result:
Where, C = Total daily contribution of a selected parameter
N_. = Number of operational occurrences per day of event i
C = Contribution per occurrence of event i
N_j = Number of occurrences per day per employee of event j
CI": = Contribution per occurrence of event j
E = Number of employees per day
= Number of occurrences per day per patron of event k
= Contribution per occurrence of event k
P = Number of patrons per day
A major advantage of this approach is that it only takes into account the com
ponent events occurring at the establishment in question when identifying the
expected wastewater loadings .
The development of this type of predictive equation for a given category
of establishments would require several types of information obtained simul-
taneously at each of several establishments within the category. The charac-
teristics of the wastewater produced per occurrence for each component event
would have to be determined as well as the frequency of occurrence of each
component event. Once developed, the predictive equation could be applied to
a given facility within the category in question by making an estimate of the
number of employees to be present and patrons served during a selected time
period.
A-91
-------
Data is available on the characteristics of certain wastewater events
such as toilet flushing, bathing and clot he swash ing, as a result of the house-
hold vastewater characterization study discussed previously. However, much
information is lacking for the variety of waste generating events which could
occur at the establishments under study. Determining the characteristics of
the component events and their frequencies of occurrence would be very diffi-
cult, requiring an extensive effort for even a single category of establish-
ments, as is evidenced by the effort expended in the characterization of house-
hold wastewaters .
This type of approach to predicting wastewater loadings was utilized for
residential households . The component waste generating events were identified
and characterized as to their quantity/quality per occurrence and the frequency
of occurrence per resident was determined for each. Thus, with knowledge of
the type of the component events to be in a planned home and an estimate of
the number of residents, a prediction of the wastewater loading from the home
can be made .
Approach 2— This simplification of approach 1 groups the contributions of
the component events into three categories: (l) operational; (2) employee;
and (3) patrons. This approach is based on the assumption that within a given
category of establishments, such as bars, certain waste generating events occur
typically and that the operational, employee and patron contributions are
sufficiently constant to yield the following type of predictive equation:
c = o + KX[E] + K2 [P] (6)
Where, C = Total daily contribution of a selected parameter
0 = Daily operational contribution
K = Employee contribution
E = Number of employees per day
K? = Per patron contribution
P = Number of patrons per day
To ensure the utility of this type of predictive equation, for a single
establishment type a narrow categorization of establishments would be required
to avoid excessive diversity. The equation parameters for a given category
could be identified by an extensive monitoring program at each of several es-
tablishments within the category. Wastewater flow information could be iden-
tified through monitoring the water use or, better yet, the wastewater produced,
with qualitative information generated through composite sampling. Simultane-
ously, the employees present and patrons served would have to be recorded.
Regression analysis could then be applied to the data to yield the equation
parameters .
To apply this type of predictive equation to a proposed establishment
within a particular category would require an estimate of the employees pres-
ent and patrons to be served during a selected time period, e.g., a day.
Approach 3 — A simplification of approach 2 would include the employee
contribution into a base flow contribution and a second constant contribution
per patron. Basically, characterization data would be expressed as a linear
A-92
-------
function of patronage in the form of
C = Kl + K2
Where, C = Total daily contribution of selected parameter
K = Base contribution
K2 = Contribution per patron
P = Number of patrons per day
Approach k—A modification of approach 3 would express the operational
and employee contributions collectively as a function of the full-time em-
ployees and some physical parameter indicative of establishment size and
operational characteristics. The number of fixture units appears to be a
readily identifiable parameter of this type. Thus, the predictive equation
would be of the following form:
C = KjEHFU] + K2[P] (8)
Where, C = Total daily contribution of a selected parameter
K = Operational and employee contribution divided by the total
establishment fixture units
E = Number of employees per day
FU = Total establishment fixture units
Kp = Contribution per patron
P = Number of patrons per day
The development of the equations outlined in approaches 3 and ^ would be
similar to that described for approach 2. Basically, monitoring of several
establishments within a given category would include recording water use and/
or wastewater flow, composite sampling of the wastewater for qualitative char-
acteristics, recording employees present and patrons served, and (particularly
for approach ^) noting the fixture characteristics of the establishment.
Regression analysis of the data generated would yield the parameters for the
predictive equations and indicate their variability.
Once developed, this type of predictive equation could be applied to a
proposed establishment if an estimate of the employees to be present and the
patrons served were made. In the case of approach k, variability in local
plumbing code requirements as to the fixtures per unit capacity should be
noted prior.to application.
Uhfortunately, this type of approach has not been utilized in any way for
any of the establishments under study. As a result, there is no existing
specific information or data of this type. However, approaches 3 and k were
evaluated at ski areas in Southern Washington and Western Oregon during the
1967 ski season (Clark, 1969). Although ski areas are not specifically one of
the establishments under study, they are very similar in that they serve a
transient population in a remote area. The general category "ski area" was
judged to include too diverse a group of establishments and it was, therefore,
divided into classes and subclasses, to facilitate predicting water use and
wastewater production. The water use was monitored at two day-lodge ski areas,
three overnight-lodge areas, and one combined day-overnight lodge. In addition,
A-93
-------
ski area patronage was identified for each monitoring period. At two of the
lodges the wastewater flow was also monitored and samples were taken.
Initially, water use relationships were derived from the data for the day
lodge and overnight lodges in the form of approach 3:
Q = K + K [P] (9)
Where, Q = Daily flow
K = Base flow constant
K? = Per patron contribution of Q
P = Number of total visitors for day lodges and number of over-
night guests for overnight lodges.
The combined day-overnight lodge equation included an extra term to allow
differentiation for more than one type of patron yielding the following
expression:
Q = ^ + KgtP^ + K3 [Pg] (10)
Where, Q = Daily flow
K = Base flow constant
Kp = Per visitor contribution of Q
P = Number of visitors per day
K_ = Per overnight guest contribution of Q
Pp = Number of overnight guests per day
The values determined for K.. , K , and K for each of the lodges studied are
presented in Table A-7&. 3
TABLE A-78. WATER USE RELATIONSHIP PARAMETERS,
L/day (Clark, 1969)
Lodge Type
Day Lodge
1
2
95$
V
133^0 8.13 -
Ul^O 2.19 -
Confidence
*
)
11.72
U.16
Limits
K3*
-
Overnight Lodges
1 13120 155 - 272
2 79^0 102 - 155
3 2950 Ul.6 - 93.2
Combined Lodge 25520 3.78 - 6.8 37.8 - 136
For equation (9), Q = K + Kg[P], for day lodges and overnight lodges and
equation (10), Q = K + K_[P..] + K_[pp], for combined lodges. All values
are expressed in L/aay.
-------
Recognizing that the base flow, K , was a function of the size of the
facility, Clark normalized K.. by dividing by the number of full-time employees
and fixture units. The resulting values of the normalized K were quite con-
sistent, ranging from 5.63 to 7.30 L/day/employee per fixture unit (FU) (1.^9
to 1.93 gal/day/employee per fixture unit) with a mean of 6.5^ L/day/employee/
FU (1.73 gal/day/employee/FU). The form of the resulting predictive relation-
shop, essentially that of approach U, was, Q = Kj/EXFU) + K2(P-|_) + K3(P2)
with KI = 6.5^ L/day/employee/FU (1.73 gal/day/employee/FU) and the values of
K2 and K3 selected from Table A-78 depending on the lodge type.
In monitoring wastewater production at two lodges Clark found that ap-
proximately 70$ of the water used was returned as wastewater and the peak
daily flow was approximately 10 times the average daily flow. Based on sample
analyses for a variety of parameters and the application of linear regression
techniques, predictive equations in the general form of Approach 3 resulted:
C =
(11)
Where, C = Total daily contribution of BOD,., COD, SS, TKN, or ^
K = Base value constant (daily contribution per employee)
E = Number of employees
K2 = Contribution of C per visitor per day
P, = Total visitors
Kl =
Contribution of C per overnight guest per day
= Total overnight guests
The values determined for the constants for BODc,
in Table A- 79.
c, TSS, TKN and TPO^ are listed
TABLE A-79. POLLUTANT CONTRIBUTION EQUATION PARAMETERS,
L/cap/day (Clark, 1969)
Kl* K2* K3*
Pollutant
Mean
95% C.L.
Mean
95% C.L.
BOD,-
COD
TSS
TKN
TPO^
* For
equation
77.
109
26.
- 21.
0.
(11),
2
8
5
M
C
g/cap/day.
2.
7-
0.
2.
15 -0.
= Kn [E] +
J_
59
63
Ikl
81
073
K [P
±3.
±6.
±5.
±1*.
±0.
] + K [P
5^
oi+
7k
77
318
18
38
133
31
6
.6
.3
.6
.99
^] . All values shown
± 59
±10*1
± 95
± 86
± 5
are
.9
.3
.3
.27
in
Several points concerning this study are worthy of note. The category of
ski areas was believed to be too broad and was divided into narrower sub-
categories. For one of these subcategories, two types of patrons were identi-
fied and included in the predictive equation. The monitoring study conducted
to develop predictive equations for this single category of establishments was
very detailed. Water use and wastewater production flow monitoring, composite
A-95
-------
wastewater sampling, and a record of patrons served were accomplished at
several establishments for a period of about six months. The variability of
the equation parameters for flow is fairly low with reasonably narrow 95%
confidence intervals (Table A-78). However, the parameters for the qualitative
equations are highly variable with wide 95% confidence intervals (Table A-79)•
In order to apply the developed equations to a proposed facility, the designer
or engineer must be able to make a reliable estimate of the employees and
patrons expected.
Approach 5—A major simplification of the previous approaches is to ex-
press the wastewater loadings totally as a function of the number of patrons
served. This approach is based on the assumption that all of the water used
and wastewater produced is somehow indirectly or directly the result of the
patrons served. Although the operational and employee contributions may
exhibit significant short-term variations in their relationship to the number
of patrons served, over the long-term and with regard to a design loading
based on some form of maximum patronage, the variations in operational-employee
contributions are most likely lower and in some cases insignificant. The form
of this predictive equation would be:
C = K-jJP] (12)
Where, C = Total daily contribution of a selected parameter
K, = Average contribution per patron served
P = The number of patrons served per day
The information necessary to quantify the parameter, K,, includes water
use and/or wastewater flow data, wastewater quality information, and a simul-
taneous record of the patrons served. The application of this type of equa-
tion, after determining the value for K , would require only an estimate of
the number of patrons expected.
This type of approach is commonly used for residential dwellings. Al-
though information is available to predict the wastewater loadings on a com-
ponent event basis as discussed in approach 1, the contribution per resident
is often set equal to that of the component events found in a "typical house-
hold." A prediction of the wastewater loading is made for a typical household
by estimating the number of residents.
This approach has also been applied to several of the establishments
under study in the field investigations previously discussed. For example,
the water use/wastewater flow from restaurants is commonly expressed per meal
served (i.e. per customer) and for schools, per student.
There are several major problems associated with the development and
application of the five previously described predictive approaches. In regard
to their development, for each category of establishments a number of such
establishments would have to be monitored for a number of days to yield statis-
tically significant results. The monitoring would necessarily include not
only water use and/or wastewater production, but also employees present and
the patrons served. Upon development, the application of a given predictive
equation to a particular establishment would require an estimate of the patrons
A-96
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to be served and possibly the employees to be present over a selected time
period. Obviously, if this estimate of patronage is not reasonably accurate,
the value of detailed predictive equations is diminished greatly. This raises
the question of how expected patronage can be accurately estimated.
Considering any establishment serving a transient population it seems
likely that actual patronage varies considerably from day to day at a. particu-
lar establishment and between establishments within the same category. This
is most likely due to quantifiable factors such as services rendered and
establishment size, as well as subtle, intangible influences, such as location
and aesthetics. As a result, an estimate of actual patronage for a selected
time period is very difficult to accomplish. However, most design is based on
some form of maximum loading rather than a form of a variable, actual loading.
Therefore, an estimate of maximum patronage of some form would be desired.
For certain types of establishments, such as motels and theaters, an estimate
of maximum patronage could be made due to a finite, identifiable capacity and
a known patron turnover rate. However, for other establishments, such as bars
and service stations, the capacity is not finite and identifiable, and the
patron turnover is highly unpredictable. For these latter type of establish-
ments, an estimate of even maximum patrons to be served could be very difficult
to make.
One approach to identifying maximum patronage for a given establishment
category would involve generating a patronage distribution. This approach
could be applied and used not only for those establishments with a finite
capacity and identifiable turnover, but also for those without such charac-
teristics. If one were to monitor patronage versus time at a given establish-
ment within a selected category, such as bars, the variations in patronage
could be identified on an hourly and/or daily basis. If several categorically
similar establishments were monitored over several days (from low to high
patronage days) and the data were normalized by dividing by an establishment
characteristic, such as seats, car spaces, square footage, etcetera, the data
could be grouped together and plotted. Ideally, a relationship such as that
shown in Figure A-33 would result. With the type of patronage information
shown in this figure for an establishment category, the designer could select
a design patronage, say 90$, thereby yielding the patrons/time/physical char-
acteristic. With a knowledge of the specific physical characteristic at the
establishment in question, the design patronage could then be identified.
This design patronage could then be utilized with one of the previously des-
cribed predictive equations to estimate wastewater loadings.
Approach 6—The difficulties associated with the generation of the pre-
viously discussed predictive equations, as well as their subsequent applica-
tion, are some of the reasons that they have not been utilized to any signi-
ficant extent. Although the characterization data in a few cases has been
generated and expressed as a function of the patrons served, the typical unit
of contribution has been a readily identifiable physical characteristic such
as seats, car spaces, square footage, etcetera, depending on the establishment
category in question. Expression of characterization data in this manner is
much simpler and its application more readily accomplished.
A-97
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Patrons/Time
Physical Parameter
90%
Observations Less Than or Equal to Stated Value, %
Figure A-33-
Hypothetical patronage distribution
for a given establishment category.
In using a physical characteristic to express wastewater characterization
data, the major assumption is that a properly selected physical characteristic
is indicative of potential patronage and vater use/wastevater production. At
first glance, this assumption does not appear to be as appropriate as an ap-
proach based on patronage. Reference is made to the field studies conducted
on each establishment category vhich indicated that results expressed as a
function of a physical characteristic exhibited a very large variation between
categorically similar establishments (e.g., laundromats) while those expressed
as a function of patronage in some form were fairly consistent (e.g., schools).
Even very similar establishments can experience significantly different patron-
age due to intangible influences.
However, since designs are generally based on maximum loadings as a re-
sult of maximum patronage, it is possible that a certain physical character-
istic may be indicative of the expected maximum patronage. This seems reason-
able since some physical characteristics such as seats, car spaces, square
footage, fixture units or a combination thereof, do establish a maximum
patronage, at least for a given turnover time period. As noted, for certain
establishments, this time period is readily identifiable, while for others it
is very difficult to identify or even estimate. If the water use and/or waste-
water production were monitored at a given establishment while it encountered
a maximum patronage, it may in fact be appropriate to express the characteri-
zation data as a function of a physical parameter. These data would then
represent a maximum loading, rather than an average loading.
The underlying assumption of this approach is that patronage is a function
of a selected physical parameter. More accurately, the assumption is that the
maximum patronage is a function of a selected physical parameter. Expressed
A-98
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in equation form, it would appear as:
Pd = K[PP] (13)
Where, P, = Maximum patronage
K = Patronage coefficient
PP = Physical parameter (number of seats, square footage,
etcetera) which provides "best correlation
For certain establishment categories which have a definite capacity and iden-
tifiable turnover such as schools, motels and theaters, the value of K can be
estimated fairly well. For others such as bars, bowling alleys and service
stations, an estimate of K would be very difficult due to a nebulous capacity
and turnover. For these latter establishment types, the development of a
patronage distribution curve as previously discussed may be necessary to
accurately estimate K. Assuming values for K were identified for a particular
establishment category, the relationship for P could be used to estimate max-
imum patronage for a proposed establishment. This value could then be used
in the previously described predictive equations, to yield an estimate of max-
imum wastewater loadings.
Approach 7—A gross simplification of the previously described approaches
and one which has commonly been used, is to ignore patronage and generate
wastewater characterization data based on a selected physical parameter. An
equation such as the following results:
C = K[PP] (1U)
Where, C = Total daily contribution of selected parameter
K = Parameter expressed as a function of PP
PP = Selected physical parameter
If the value of K were determined at one or more establishments within a given
category which were experiencing a high level of patronage, it would be useful
for design purposes. However, if K were determined at establishments encoun-
tering a very low patronage, it would be incorrect to use this K for design.
To generate this type of relationship, it would be necessary to monitor
water use and/or wastewater flow on a selected time basis (e.g., daily) for
volume information and to composite samples from the wastewater for qualita-
tive data. If a number of establishments were monitored over a number of days,
and the data were expressed as a function of a common physical parameter, the
data could be combined to yield statistical results for the category in ques-
tion. In regard to applying these results in a predictive manner, it would be
misleading and incorrect unless the data were generated under high patronage
conditions. To ensure that the data were generated under high, design-type
use, one could either specifically select monitoring days where high use would
be encountered or monitor over a number of days so that high use days would be
included. Then, by having a knowledge of the selected physical characteristic
at a proposed establishment, the value for K of the establishment category in
question could be used to yield an estimate of the maximum wastewater loadings
expected.
A-99
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As noted previously, this type of approach has commonly been used for
many of the establishments under study, as well as for others. The obvious
reason for this is the comparative simplicity in data generation and applica-
tion. Unfortunately, the use of this approach without regard to the basis for
the approach has often led to high variability in the data for a given estab-
lishment category.
Approach 8—A final approach includes a minor alteration of approach 7 in
that a base flow constant would be included to more accurately represent the
data. An equation similar to that of approach 3 results:
C = ^ + K2[PP] (15)
Where, C = Daily contribution of Q, BOD-, TSS, . . . per time
K- = Base flow constant
Kg = Daily contribution per physical parameter
PP = Selected physical parameter
The generation and application of this type of approach is similar to that of
approach 7«
McCuen, Sutherland and Kim (1975) found this suitable for predicting
shopping center water use. The values of parameters equivalent to K]_ and K2
were determined for a number of shopping centers (department stores and mall
shops) utilizing water use information and physical characteristics. For a
complete discussion of this example, reference is made to the individual
establishment field studies section on Shopping centers.
Daily Qualitative Characteristics—
Within a reasonably narrow establishment category, establishments should
typically contain similar waste generating events, although perhaps different
in number. The occurrence of theee waste generating events as a result of
basic operation and patron related activities results in the production of
wastewater. At a given establishment the concentration of various pollutants
in the wastewater stream would be expected to vary during the day due to the
intermittent occurrence of different events. Similar variations may also
exist from day to day, especially between high and low patronage days due to
the influence of operational flows and clean water flows from automatic events
such as urinal flushing. Further, daily variations may result due to special
events such as a potluck dinner at a church. Between categorically similar
establishments, daily effluent concentrations determined by short-term moni-
toring could differ for the above reasons as well as some differences in
waste generating events.
Although variations may occur in the strength of a wastewater at a given
establishment and between categorically similar establishments, it would seem
that for the purpose of estimating the chemical/physical characteristics of an
establishment category's wastewater, representative daily composite concentra-
tions should suffice. These concentrations could be determined through some
form of composite wastewater sampling at several establishments. These chemi-
cal/physical concentrations could be used in combination with the daily waste
flow volume estimated by one of the detailed approaches described earlier to
yield an estimate of pollutant mass/day if desired.
A-100
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A comparison of this concentration approach versus a detailed mass ap-
proach may be made utilizing the data generated by the waste-water characteri-
zation study at winter ski areas (Clark, 1969). As part of the study, the
wastewater flow volume was measured and composite samples taken at each of two
overnight-day use ski areas over approximately two weeks. Analyses were per-
formed for BODc, suspended solids and other standard chemical/physical para-
meters. A summary of the values determined for selected parameters is shown
in Table A-8d. As shown, the day-to-day variations in the concentration of
any of the parameters is not excessive, nor is the variation between the two
establishments .
TABLE A-80.
SKI LODGE WASTEWATER CHARACTERISTICS
(Clark, 1969)
Ski Lodge A
Ski Lodge B
Parameter
Samples
BOD5, mg/L
TSS, mg/L
TKN, mg/L
TPOij, mg/L
Flow, L/day
Mean
9-12
395
321
76.6
12.7
31,600 L/day
Std.
Deviation
_
126
177
-
2.1*
—
Mean
15-16
382
372
80
13.2
56,UOO L/day
Std.
Deviation
_
170
208
29.3
6.6
-
Average
^
388
3^6
78
13
-
Using the individual wastewater characterization data and records of daily
visitors and overnight guests which had been obtained simultaneously in combi-
nation with the employee and fixture unit characteristics of each establishment,
predictive equations of the following form were generated:
Flow = a(E)(FU) + b(TV) + c(G) (l6)
Pollutant Mass = x(E) + y(TV) + z(G) (17)
Where, a,b,c,x,y,z = Equation parameters
E = Employees
FU = Establishment fixture units
TV = Total daily visitors
G = Total overnight guests
The predictive equations suggested for use in design for flow, BOD^, and TSS
were as follows:
L/day = 6.5^ (E)(FU) + 6.80(TV) + 136(G) (l8)
g BOD5/day = 77.2(E) + 6.13(TV) + 78.5(G) (19)
g TSS/day = 26.8(E) + 5-90(TV) + 132(G) (20)
A-101
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An example will serve to compare the use of an average pollutant concentration
and a detailed flow equation compared to a detailed mass equation to estimate
daily pollutant contributions from a given establishment.
Lodge A:
Employees = 15
Fixture Units = 300
Daily Visitors = 2225
Daily Overnight Guests = 75
Detailed Pollutant Mass Equation:
g BOD5/day = 77.2(15) + 6.13(2225) + 78.5(75) (19)
= 20,700 g BOD^/day
g TSS/day = 26.8(15) + 5.90(2225) + 132(75) (20)
= 23,1*30 g TSS/day
Average Pollutant Concentration & Detailed Flow Equation:
L/day = 6.5^(15)(300) + 6.8(2225) + 136(75) (l8)
= 5^,770 L/day
Average BOD .-/day = 388 mg/L
g BOD5/day = (388 mg/L)(51*«770 L/day)(8.3^ lVgal)(U$li g/lb)
(3.78 L/gal)(lO gal/MG)
= 21,290 g BOD./day
Average TSS = 3^6 mg/L
g TSS/day = (3^6 mg/L)(5^.770 L/day)(8.3^ lb/gal)(U5U g/rb)
(3.78
= 18,980 g TSS/day
(3.78 L/gal)(lO gal/MG)
As indicated by this example, the use of average concentrations determined
through daily composite sampling in combination with a reasonable estimate of
flow volume yielded a mass/day contribution very similar to that provided
through use of a very detailed mass/day prediction equation.
A further ramification of this concentration-volume approach is that it
may be possible to predict the strength of the wastewater produced by dif-
ferent establishment categories if the waste generating sources and patron
activities are reasonably similar. What may result are larger establishment
groupings, including several establishment categories, for the purpose of
estimating wastewater strength. For example, it is conceivable that the
strength of the wastewater produced by bars, bowling alleys, and theaters may
be sufficiently similar to form one such group. Unfortunately, data are
lacking to support or refute this possibility.
A-102
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This type of approach is commonly utilized for municipal wastewater faci-
lities design, with average concentrations and their ranges utilized for para-
meters such as BODtj and suspended solids. To convert these concentrations to
a mass, an estimate of waste flow volume is made and a simple conversion is
applied. Certain of the qualitative information presented in the general
guideline tables in terms of mass/day/parameter would appear to have been
generated in this manner, i.e., typical domestic wastewater concentrations
have been converted to mass values by utilizing an estimated flow volume.
Peak Flow Characteristics—
The intermittent occurrence of various waste generating events within an
establishment or facility results in the production of a wastewater which
varies in both volume and strength with time. The approaches discussed in the
previous sections have dealt primarily with the prediction of waste loadings
on a daily basis rather than on a short-term basis, such as per hour. For the
various characterization parameters, short-term peak loadings appear to be of
marginal utility with the exception of flow volume. Peak sewage flows are
often critical to design, and methods for their estimation merit further dis-
cussion.
The short-term peak sewage flow from a given establishment is a function
of the types and numbers of waste generating fixtures present, such as showers,
sinks, toilets, dishwashers, washing machines, etcetera. Obviously, the maxi-
mum peak loading which could physically occur would result under simultaneous
discharge from all fixtures present. This peak rate could be easily estimated
with a knowledge of the fixtures present and their typical flow rates and/or
volume per use. However, the likelihood of all fixtures discharging at once
would seem to be very small. Rather than this maximum peak flow, it would
seem that an "expected peak flow" would be more useful and appropriate.
To identify expected short-term peak flows, there appear to be two basic
approaches. The first is a probabilistic approach based on the types and
numbers of fixtures present, typical flow rates and volume per use, and the
probability of their simultaneous occurrence (in part or in total). The
second approach is more of a brute-force monitoring approach yielding expected
peak flows for a given establishment type as a result of water use/waste flow
monitoring versus time of day. A discussion of each approach follows.
Probabilistic approach—This type of approach is basically that developed
by Hunter (19^0, 19^1) commonly referred to as the "Fixture-unit Method."
Originally developed for predicting peak water demands within buildings, it
has commonly been used to also estimate peak sewage flows. A discussion of
this approach was given in the section summarizing the existing information.
Briefly, the water demand through a fixture was seen to be a function of the
flow rate, length of use and frequency of use. The fixture unit was defined
as a water demand equivalent to 7.5 gallons per minute and various fixtures
were then assigned a certain number of fixture units based upon their water
use characteristics. Utilizing probability theory, Hunter developed curves
relating the expected peak water demand to the number of fixture units present
(refer to Table A-U6 and Figure A-15).
A-103
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Field monitoring—Continuous water use/waste flow monitoring at several
establishments within a given category over a sufficient length of time would
yield information on peak flow (e.g. peak hourly flow). Further, periods of
low or no flow could be identified. The major concern with this approach is
that the establishments monitored be representative of those typically included
in the given establishment category and that the monitoring be conducted over
a sufficient length of time so that the peak flows are actually encountered.
As part of several of the establishment field studies previously discussed,
peak flows have been identified and occasionally flow hydrographs developed.
For the most part, this monitoring has been restricted to water usage, due to
the relative simplicity of gathering this type of data. Although water usage
does not necessarily equal wastewater production in either volume or flow
pattern, peak water usage is often indicative of peak sewage flow.
To allow a general review of selected peak flow data determined in the
establishment studies, Table A-8l has been prepared. The ratio of peak hourly
flow to mean daily flow determined through in situ monitoring has been calcu-
lated where possible and presented. As shown, for certain establishments,
peak hour ratios have not been identified, while for others more than one study
has been conducted. It is interesting to note that where more than one study
has been conducted on a given establishment type, the peak hour/mean daily
values determined are reasonably consistent. However, between very different
establishments such as restaurants and churches, there is a significant dif-
ference in the peak flow ratios determined.
TABLE A-8l. PEAK HOURLY FLOW RATIO DATA
Establishment
Ratio
Peak Hour/Mean Daily
Bars/Taverns
Bowling Alleys
Campgrounds & Picnic Parks
Churches
Country (Golf) Clubs
Laundromats
Marinas
Motels
Restaurants
Schools
Service Stations
Shopping Centers
Sports Facilities
Theaters
. 0
U.5, 6.9
2.0, 2.7
3.2-5, 3.3-3.7, 9-1-l8.2
19.5
2.6, 2.0, 2.5
7.5
Although it is difficult to draw conclusions from the data presented, it
appears that those establishments with relatively high numbers of fixture
units and reasonably steady daily patronage such as schools, shopping centers,
and restaurants encounter a lower peak flow ratio than those with relatively
low numbers of fixture units and variable daily patronage, such as service
A-10U
-------
stations and churches. This seems reasonable, since the peak hourly flow is
not affected by low daily-use days, whereas the mean daily flow may be signi-
ficantly reduced.
Discussion—
A summary of the approaches previously discussed is presented in Table
A-82. These were reviewed and compared in an attempt to identify which should
in general be used to estimate the loading of a given parameter. Considera-
tion was given to (l) the type and degree of monitoring required for develop-
ment, (2) the information necessary to apply an approach once developed,
(3) the accuracy of prediction expected, and (k) previous successful applica-
tions for establishments such as those under study. Based on this analysis,
certain types of approaches have been identified as most appropriate and are
recommended as described in the following sections.
Daily quantitative characteristics—Consideration of the existing char-
acterization data and the preceding analyses of various approaches to generate
data in a predictively useful manner clearly indicated that there are two,
distinct levels of predictive accuracy possible depending on the type of ap-
proach employed. With regard to estimating average and maximum daily flow
volumes, the lower level of predictive accuracy appears to result from the use
of approaches which generate characterization data as a function of an estab-
lishment physical parameter such as square footage, seats, car stalls, etcetera.
An exception to this occurs when an estimate is desired for maximum daily flow
and the establishment category in question possesses a finite capacity and
known turnover rate. Since the maximum patronage is a function of an establish-
ment size characteristic, the maximum daily flow, produced under maximum pa-
tronage, is likewise a function of the establishment size. The higher level
of predictive accuracy appears to result when an approach is utilized which
generates characterization data as a function of patronage.
The approaches presented and discussed for predicting average and peak
daily waste flow volumes were divided into three groups of approaches, con-
sisting of those based on: (l) component event wastewaters (Al), (2) patron-
age (A2 to A5), and (3) establishment size(A7,A8). All of the approaches
within the same group require the same general monitoring efforts for develop-
ment and/or information for application. Of these three groups, the first
two appear to offer higher predictive accuracy but require greater developmental
and application efforts, than the third. After consideration of all three
groups, the second group (A2 to A5) which generates the characterization data
as a function of patronage is felt to offer the proper balance between accuracy
of prediction and developmental/application requirements and is, therefore,
recommended.
Monitoring requirements to enable the development of the recommended
approaches include simultaneous water use and/or wastewater flow volumes and
patronage measurements. Additionally, establishment size would be noted as
indicated by fixture units, seats, etc. Analysis of the data would then indi-
cate which of the approaches, A2 to A5, provided the greatest accuracy of
estimate. It should be noted that the monitoring would also allow analysis of
the data for approaches AT and A8.
A-105
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To apply any of the approaches A2 to A5 requires an estimate of expected
patronage with approach A2 also requiring an estimate of employees and estab-
lishment size. As discussed previously, expected patronage, especially maxi-
mum patronage, can be estimated readily for certain categories of establish-
ments such as motels and theaters due to a finite capacity and known patron
turnover rate. However, for other establishments, such as bars and service
stations, the capacity is not finite and the patron turnover is highly unpre-
dictable, thus making patronage estimates very difficult to accomplish. For
these establishments an empirical relationship of patronage and establishment
size [P = f (size)] would have to be derived during the monitoring phase.
With the patronage estimates, average flow could then be estimated using
average patronage with peak daily flow the result of maximum daily patronage.
Daily qualitative characteristics—As indicated in the preceding analysis
of characterization approaches, it appears appropriate to generate qualitative
characterization data for a given category of establishments in concentration
form. The generation of this data for a given category of establishments would
require the collection and analysis of several flow composited samples from
each of several establishments within the category. As noted previously, the
category should be descriptively narrow and contain establishments possessing
similar waste generating sources. Conversion of the concentrations to mass
contributions could be accomplished by utilizing an estimate of the waste flow
volume obtained as previously recommended. To apply the resulting characteri-
zation data would only require assigning the establishment in question to a
particular establishment category.
Peak quantitative characteristics—The characterization of peak wastewater
flow is recommended by continuous water use or wastewater flow monitoring
during expected hours of peak flow. Expression of the peak flow appears most
useful as a ratio of the mean daily flow measured. Thus, this monitoring
should ideally be accomplished along with the monitoring conducted to charac-
terize daily wastewater flow volumes. It is possible that this type of
characterization approach may facilitate the development of a probabilistic
approach similar to that developed by Hunter (19^0, 19^-1), as discussed
previously.
To summarize briefly, the following types of approaches are recommended
for generating and presenting characterization data for the types of estab-
lishments under study in a predictively useful and accurate manner:
Daily Quantitative Contributions—
Q = f (Patronage )
^ave ° ave
Q = f (Patronage )
inax e max
Patronage values required for application estimated based
on establishment size or a derived relationship.
Daily Qualitative Characteristics—
The results of statistical analysis of flow-composited
samples with mass contributions calculated.
A-10T
-------
Peak Flow Characteristics—
Continuous water use and/or wastewater flow monitoring
with expression as peak to mean daily.
Characterization Data Generation
In the discussion at the close of the summary of the existing information
section, the characterization data provided by previous field studies was
briefly reviewed and considered as to its extent, but this was done without
regard to the approach used to generate and present the data. However, the
approach used to generate and present characterization data is of prime impor-
tance, and to a large degree, determines the predictive accuracy and reliabi-
lity of the data. Thus, consideration of the existing data must necessarily
include consideration of the approach utilized to generate the data. A review
of the existing information from previous field studies, considering the
amount of data available as well as the approach used for its generation,
indicated the characterization data which was altogether lacking or in need of
verification for each of the establishments under study and several key para-
meters. This information, as presented in Table A-83 shows a substantial
amount of characterization data lacking or in need of verification.
At the onset of this study, it was anticipated that after compiling a
comprehensive summary of the existing characterization data for the establish-
ments selected for study, consideration of the summary would indicate the data
which was lacking or in need of verification, and then field studies could be
readily accomplished to provide the necessary data. However, after the exis-
ting characterization data was compiled and evaluated and an analysis of
characterization methods was conducted, it became clear that proper character-
ization of the wastewaters from the study establishments was a considerably
more difficult task than had been originally envisioned. Thus, it became
obvious that this study could not hope to provide all the missing pieces of
data due to finite resources and time constraints, but rather would indicate
which pieces of data were lacking, recommend the proper approaches to generating
the necessary data, and provide as much additional data as possible.
Data Generation Methods—
To provide additional characterization information, data was collected
regarding quantitative and qualitative characteristics for several categories
of establishments. To facilitate data gathering, the cooperation of two,
large liquid waste pumpers/haulers was secured. It was discovered that many
of the establishments under study employed holding tanks for disposal of their
wastewaters and it was felt that this would facilitate monitoring efforts,
both for quantitative, as well as qualitative characterization.
Quantitative Characterization—Attempts were made to include all of the
establishments under study for which additional waste flow volume data was
necessary in this effort. In total, 18 establishments within 7 of the cate-
gories under study were included. As a result of certain political considera-
tions, measurements had to be obtained from holding tank pumpage records,
which in most cases covered a two-year period. A list of the establishments
included and their characteristics appear in Table A-8U. Attempts were also
made to secure the cooperation of several local establishments to allow the
A-108
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A-109
-------
monitoring of water use. However, a complete unwillingness to participate in
any form by several establishments quickly discouraged these efforts.
TABLE A-81*. ESTABLISHMENT CHARACTERISTICS - QUANTITATIVE CHARACTERIZATION
No.
1
2
3
h
5
6
7
8
9
10
11
12
13
lU
15
16
IT
18
Establishment
Type
Bar/Tavern
Bar/Tavern
Campground
Church
Church
Church
Church
Country Club
Country Club
Country Club
Drive-in Restaurant
Restaurant
School
Gas Station
Gas Station
Gas Station
Gas Station
Gas Station
Characteristics
50 seats, restrooms
110 seats , restrooms
230 sites , comfort stations , laundry
125 members , restrooms , kitchen
facilities
160 attendants on Sunday, restrooms,
kitchen
200 attendants on Thursday and
Sunday, restrooms
360 members , restrooms , kitchen
facilities
Golfing, 75 seat restaurnat,
locker rooms /showers
Golfing, 60 seat restaurant,
locker rooms /showers
Golfing, TOO seat restaurant,
locker rooms/showers
20 car stalls, 20 seats, restrooms
300 seats
l60 students , restrooms
2 bays, 2 pump isles, restrooms
3 bays, 2 pump isles, restrooms
2 bays, 2 pump isles, restrooms
2 bays, 2 pump isles, restrooms
2 bays , 2 pump isles , restrooms
Period of
Data
lM -
5/7U -
5/T5 -
1/7U -
10/7U -
U/7U -
9/T^ -
11/7U -
T/T5 -
10/T1* -
10/7U -
10/7U -
10/T1* -
12/7U -
10/7U -
12/7U -
12M -
10/7U -
12/7U
12/7U
9/76
9/76
10/76
9/76
8/76
10/76
-9/76
10/76
10/76
10/76
10/76
10/76
10/76
10/76
10/76
11/76
Qualitative characterization—Qualitative characterization was conducted
at lU establishments within five of the categories under study: churches,
country clubs, restaurants, schools and service stations. A list of the
establishments included and their characteristics is shown in Table A-85.
This characterization was accomplished through sampling of the wastewater
in the holding tank serving each of the establishments. Each time the holding
tank was pumped, a sample of the wastewater was collected. The sample was
obtained in three portions, at the beginning, middle and end of pumping, off
of a drain valve on the centrifugal pump located on the pumper tank. After
collection, the samples were refrigerated until they were transported back to
the University of Wisconsin for analysis. Each sample collected was analyzed
routinely for chemical oxygen demand, total and suspended solids, total
Kjeldahl nitrogen and total phosphorus according to procedures outlined in
Standard Methods (1971). The results of the analyses were subsequently
A-110
-------
TABLE A-85. ESTABLISHMENT CHARACTERISTICS - QUALITATIVE
WASTEWATER CHARACTERIZATION
Establishment
No.
1(8)*
2(10)
3(*0
1+
5(12)
6
7(11)
8
9(17)
10(15)
11(18)
12
13(16)
lU
* Number
Type
Country (Golf) Club
Country (Golf) Club
Church
Church
Restaurant
Restaurant
Drive-in Restaurant
School
Service Station
Service Station
Service Station
Service Station
Service Station
Service Station
in parenthesis is the
Characteristics
Golfing, 75 seat restaurant, locker rooms
w/showers
Golfing, 700 seat restaurant, locker rooms
w/showers
125 members , restrooms ,
-
300 seats , restrooms
-
20 car stalls , 20 seats
Elementary
2 bays , 2 pump islands ,
3 bays , 2 pump islands ,
2 bays, 2 pump islands,
—
2 bays, 2 pump islands,
-
no. of the establishment
kitchen facilities
, restrooms
restrooms
restrooms
restrooms
restrooms
as shown in
Table A- 8^
analyzed to determine the mean, coefficient of variation and range of concen-
tration measured for each category involved.
Results and Discussion—
Quantitative characterization—The volume of wastewater produced per day
by each of the establishments is presented in Table A-86. Also shown is the
period of days over which each individual volume measurement was made. Uti-
lizing the available physical characteristics of each establishment, the flows
were converted to volume/day/unit values as presented in Table A-87.
Qualitative characterization—The results of qualitative analyses were
grouped according to category and subsequently analyzed. The mean, coefficient
of variation and range of values determined for each category are presented in
Table A-88. As shown, there is a significant difference between the concentra-
tion of the selected parameters between categories of establishments. However,
within each category the variation of concentrations is reasonably low as
evidenced by the coefficients of variation. These results appear to support
the previous discussion and recommendation that the use of average concentra-
tions of composite wastewater samples is acceptable as a characterization
approach. -
It should be noted that the wastewater generated by each establishment
remained in the holding tank for varying periods of time prior to sampling.
Also, the entire contents of the holding tank was not always pumped completely.
As a result, the values identified for COD and suspended solids may be somewhat
less than those in the fresh, raw wastewater.
A-lll
-------
TABLE A-86. DAILY WASTE FLOW VOLUMES, L/day
Wo.
1
2
3
k
5
6
7
8
9
10
11
12
13
lU
15
16
IT
18
Establishment
Type
Bar/Tavern
Bar/Tavern
Campground
Church
Church
Church
Church
Country Club
Country Club
Country Club
Drive^n Restaurant
Restaurant
School
Service Station
Service Station
Service Station
Service Station
Service Station
Meas .
Period*,
Days
8
6
3t
31t
8lt
38t
1*3
8t
5t
3t
8
3
23t
23t
Ut
9t
5
8
Data
Pts.
U5
38
101
27
8
21
16
55
55
193
108
23k
22
26
lUl
63
1U8
122
Mean
281+Ot
2080t
23810
36ot
300
290t
270t
336ot
2650t
7820t
281+Ot
5670t
lUTOt
930
l*910t
2190t
H5l*0t
23Uot
95$
21+20
1700
19660
290
210
2UO
230
2530
2230
7030
2610
5370
870
760
1+350
1890
1+120
2150
C.I.
- 3290
- 2530
- 27600
- 1+50
- 380
- 370
- 330
- 1*380
- 3lUo
- 8690
- 3ll*0
- 9750
- 2570
- 1130
- 5590
- 2530
- 1+990
- 2570
* Average period between holding tank pumpage. Includes non-working single
days, but no off-season.
Log-normalized data.
TABLE A-87. DAILY WASTE FLOW, L/day/unit
No.
1
2
3
1+
5
7
8
10
11
Establishment
Type
Bar
Bar
Campground
Church
Church
Church
Country Club
Country Club
Drive-in
Unit
Seats
Seats
Campsite
Registration
Sunday Attendant
Sunday Attendant
Member
Golfer
Golfer
Patron Car Space
Mean
57
19
102
300*
2.3
(15- 5t)
1.9
(I3t)
0.8
(5.3t)
15*
6M*
36
95$
1+9
15
87
1.9
1.1
0.6
33
C.I.
- 6H
- 23
- 121
-
- 2.6
-
- 2.3
-
- 0.9
-
-
-
- 39
Restaurant
(continued)
A-112
-------
TABLE A-87 (continued)
Establishment
No.
Type
Unit
Mean
C.I.
12
13
ll*
15
16
17
18
Restaurant
School
Service
Service
Service
Service
Service
Station
Station
Station
Station
Station
Seat
Student
Bay
Car Served
Bay
Bay
Bay
Car Served
Bay
19
9-1
(13*)
u?o
8.7*
1630
1100
2270
23*
1170
18 -
5-3 -
330 -
_
lUUo -
950 -
2060 -
_
1080 -
20
16
570
1850
1290
21*90
1290
* Values presented as L/unit.
t Assumes all flow on Sunday, value expressed as L/day/worshiper.
+ Assumes all flow on Monday-Friday, value expressed as L/school day/student,
The results of this study have been combined with the results of the
previous investigations to provide a comprehensive summary of water use/waste-
water characterization data for the selected establishments. An evaluation of
the data was conducted in an attempt to identify expected loadings from estab-
lishments within each category. If several pieces of data were available for
a given parameter and establishment, a range of values was determined. Due
to differences in establishment type and monitoring methods this was felt to
be more appropriate than presenting a mean value. However, if a piece of
data was felt to be unreliable due to the method of generation, it was omitted.
The results of this evaluation are presented in Table A-89 for quantitative
parameters, including mean daily flow and peak flow ratios. A similar summary
table was not prepared for qualitative parameters due to a general lack of
reliable information.
Summary
A substantial amount of characterization data presently exists. However,
certain specific data are yet lacking or in need of verification. Additional
extensive field studies are necessary, utilizing the recommended characteriza-
tion approaches, to provide the missing data for establishments included in
this study.
A-113
-------
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A-115
-------
METHODS FOR IN-HOUSE ALTERATION OF WASTEWATER CHARACTERISTICS
The characteristics of a waste-water can have a major impact on the design
and performance of any wastewater treatment and disposal system. Recognizing
this fact, increasingly more emphasis is being directed toward developing
methods for in-house alteration of the raw wastewater characteristics. Elimi-
nation of potential pollutants at the source, such as flow, oxygen-demanding
substances, suspended solids, nutrients, and pathogenic organisms, or their
isolation in a concentrated waste stream could enhance conventional disposal
methods or facilitate the development and use of innovative alternatives.
Consideration of the results of the previously discussed characterization
work readily indicates that two powerful strategies for altering typical waste-
water characteristics are (l) waste flow reduction and (2) waste segregation.
A discussion of each strategy follows. It should be noted that although the
primary thrust of the following discussions has been directed toward residen-
tial dwellings, many of the concepts and techniques presented have application
to non-residential establishments as well.
Waste Flow Reduction
Methods to Achieve Waste Flow Reduction—
Waste flow reduction involves reducing the volume of water used within a
household or other establishment, thereby producing a reduction in the volume
of wastewater produced. To accomplish this, an array of concepts, techniques
and devices have been proposed. To illustrate the extent and diversity of
these methods, Table A-90 has been prepared. As shown, waste flow reduction
methods may be divided into three major categories: (l) elimination of non-
functional water use, (2) water-saving fixtures, devices and appliances and
(3) wastewater recycle/reuse systems.
TABLE A-90. WASTE FLOW REDUCTION METHODS
I. Elimination of Non-Functional Water Use
A. Eliminate Wasteful, Water-Use Habits
B. Maintain Non-Excessive Water Pressure in House Supply
C. Maintain Plumbing in Good Repair
II. Water-Saving Devices, Fixtures and Appliances
A. Toilet
1. Conventional toilet, tank inserts
2. Dual-flush toilet devices
3. Shallow-trap flush toilet
U. Mechanically-assisted, low-volume flush toilet
a. Compressed air
b. Vacuum
c. Grinder
(continued)
A-116
-------
TABLE A-90 (continued)
5. Non-water carriage toilets
a. Composting
b. Incinerator
c. Closed-loop recycle (water or oil)
B. Bath/Shower
1. Shower flow controls
2. Reduced-flow showerhead
3. Pressure-balanced mixing valve
k. Air-assisted low-flow shower system
C. Clotheswasher
1. Adjustable cycle settings
2. Suds-saver feature
D. Dishwasher
1. Adjustable cycle settings
E. Sink Faucets
1. Faucet inserts
2. Reduced-flow faucet valves
3. Faucet aerators
k. Pressure-balanced mixing valve
III. Wastewater Recycle/Reuse System
A. Bath/Laundry Wastewater Reuse for Toilet Flushing
B. Bath/Laundry Wastewater Reuse for Exterior Uses
C. Combined Wastewater Reuse for Toilet Flushing
Elimination of non-functional water use—Non-functional water use is
typically the result of (1) wasteful, water-use habits, (2) excessive pressure
in the house supply, and (3) inadequate plumbing and appliance maintenance.
Wasteful water use habits, such as using a toilet flush to dispose of a ciga-
rette butt or operating a clotheswasher or dishwasher with only a partial load,
produce needless quantities of waste flow. Excessively high water pressure in
the house supply can result in unnecessarily high water flow rates through
faucets, showerheads and similar fixtures. Unseen or apparently insignificant
leaks from household fixtures and appliances can generate substantial quanti-
ties of waste flow. Obviously, the potential for waste flow reduction through
elimination of these types of non-functional water uses varies tremendously
between homes depending on existing characteristics.
Water-saving devices, fixtures and appliances—To reduce the quantity of
water used by a given household fixture or appliance in accomplishing a given
task, conventional fixtures are being redesigned and new and innovative devi-
ces, fixtures and appliances are under development. Among these are toilet-
tank inserts, faucet aerators, showerhead inserts, flow-regulated showerheads
and faucets, water-saving dishwashers and clotheswashing machines and innova-
tive toilets, including reduced flush and non-water carriage systems. Since
toilet flushing, bathing and clotheswashing collectively account for over 10%
of a typical household's waste flow volume, efforts to achieve major reductions
have logically been concentrated in these three areas.
A-11T
-------
Wastewater recycle/reuse systems—A final method for reducing waste flow
volumes involves processing all household wastewater or the fractions produced
by certain activities for subsequent reuse. The flow sheets suggested have
been numerous and vary considerably. However, major emphasis has been placed
on recycling bath and laundry wastewaters through some form of treatment pro-
cess for use in flushing water-carriage toilets and lawn irrigation.
Evaluation of Flow Reduction Methods—
A limited number of investigations have been conducted to identify the
actual waste flow reductions possible through utilization of certain of the
previously described methods. A brief review of several studies follows.
In 1969, Bailey, et.al., reported the results of a literature survey of
methods for waste flow reduction from households conducted by the Electric
Boat Division of General Dynamics. Flow reductions were projected for various
water-saving devices used in a hypothetical household. To enable these pro-
jections, base water use was estimated at 210 L/day (55 gal/day) for household
uses including 57 (15) for dishwashing, 130 (35) for laundry, and 19 (5) for
cleaning, and 190 L/cap/day (50 gal/cap/day) for personal uses including 11
(3) for drinking and cooking, 78 (20) for bathing, 8 (2) for oral hygiene and
9U (25) for toilet flushing. The waste flow reductions predicted were,
Flow control shower heads - 23 L/cap/day
Faucet aerator - 1.9 L/cap/day
Shallow-trap toilets - 28 L/cap/day
Dual-flush cycle toilet - 66 L/cap/day
Washing machine sudsaver - U.5 L/cap/day
In 1971, a follow-up study supported by the U.S. EPA was performed by
General Dynamics to field evaluate certain promising methods identified in
their first study. Eight households were included in the demonstration pro-
ject, six in southeastern Connecticut and two in San Diego, California. At
each of the homes, water meters were installed in the house supply line, as
well as in the individual lines to the toilet, bath/shower, and laundry (five
homes only). The water usage was recorded by the homeowners on a weekly
basis. To provide base flow data, water use was monitored for six months
prior to device installation. Then, flow reducing devices and recycle systems
were installed, including shallow-trap toilets, two types of dual-flush toilet
devices, flow-reducing showerheads, and a wastewater recycle system, and water
was monitored for one year. After this period, the devices were removed and
water use was monitored for another six months. A summary of the waste flow
reductions produced by the devices is presented in Table A-91.
Flow-reducing showerheads were found to produce only a minor reduction in
the total household flow. The investigators believed this to be due to the
fact that the residents preferred baths over showers. The shallow-trap toilets
produced a moderate reduction of about 3% to 9% of the total household flow.
As expected, the most substantial water-savings (26%) were achieved with the
recycle systems which processed the bath and laundry wastewaters for toilet
flushing and lawn sprinkling.
A-118
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TABLE A-91.
WASTE FLOW REDUCTION SUMMARY
(Cohen and Wallman, 197*0
Device
Flow Limiting
Shower Head
Shallow- Trap
Toilets
Dual Flush
Toilet Devices
Wash Water
Recycle System
Description
or Type
9.5 L/min
13.3 L/min
9.5-12.5 L/ flush
8/17 L/flush
14/17 L/flush
Storage •»•
Filtration -»•
C12 -»• Toilet
Flushing/
Sprinkling
Units
Tested
3
8
6
k
k
3
Average
Occupants
5.8
3.8
fc.5
2.8
3.2
6.3
Water
L/cap/day
1.6
3.7
1U.8
20.5
12. k
MK
Savings
% of Total
0.8$
1.2%
6.9%
8.6%
3.3fo
26. %
This investigation also included two important aspects of waste flow
reduction, namely, homeowner acceptance of the devices utilized and the net
costs incurred through their use. Homeowner acceptance was evaluated through
distribution of a formal questionnaire to the l6 adult occupants of the eight
study homes. A summary of the questionnaire results in terms of user accep-
tance is shown in Table A-92. As shown, there was a clear indication of these
homeowners' acceptance of the waste flow reduction devices utilized, with the
possible exception of utilizing recycled wastewater for lawn watering.
TABLE A-92. HOMEOWNER ACCEPTANCE OF FLOW REDUCTION DEVICES
(Cohen and Wallman, 197*0
Device or System Tested
Number of
Respondents
Percent of Responses
Indicating Acceptance
Flow Limiting Shower Heads 16
Shallow Trap Toilets 12
Dual Flush Devices 6
Wash Water Recycle for Toilet Use 6
Wash Water Recycle for Lawn Sprinkling h
83%
100%
61%
The costs for installation and operation of the various waste flow reduction
devices was computed and the net savings or costs incurred were estimated
based on typical water and sewer rates in the study areas. Although such
calculations are of questionable validity due to rate structure mechanics, the
investigators perceived the devices to be economically justifiable.
A-119
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In 1971» the Washington Sub-urban Sanitary Commission (WSSC) began actively
promoting public water conservation in an attempt to reduce wastewater flow
volumes (Bishop, 1975). A major phase of WSSC's program involved the evalua-
tion of pressure reducing valves, toilet tank inserts and flow-reducing shower
heads. The evaluation involved the installation of U,800 devices in 2,^00
residential units; approximately one-half were single-family dwellings with
the other half apartments and townhouses. In addition to the water-saving
devices, a booklet containing suggestions for water conservation was distri-
buted to each participant. Based on the results of one year of operation with
the water saving devices, the apartment units and single family units had
reduced their consumption by 12 and 18-20 percent, respectively, through use
of the toilet tank inserts (weighted, water-filled plastic bottle). Flow-
reducing shower heads (11.3 L/min) yielded a 1.2% reduction in consumption. It
should be noted that a major portion of these water savings may have been due
to improved water-use habits as a result of the information booklet distributed.
Follow-up studies by the WSSC included the installation of showerhead
inserts in 100 townhouses (Bishop, 1975). Based on water-use monitoring over
a ten-month period, daily water use was found to increase by about 2.5%. The
investigators attributed the increase and the contradictory results of the
two studies to user lifestyle habits. The lack of a supervised installation
program in the latter study was also felt to be responsible for the water-use
increase.
As part of the effort to characterize household wastewater conducted as
a phase of this study, event water use was monitored at eleven homes for a
total of U3U days. To assess the potential for waste-flow reduction in these
homes, four water-saving methods were hypothetically applied to each home.
These methods included: (l) reducing the toilet flush to 11 L (3 gal);
(2) replacing the existing clotheswasher with a sudsaver model; (3) controlling
the volume of water used for bathing to 57 L (15 gal) per bath or shower, and
(^) recycling the bathing and laundry water for toilet flushing. The calcula-
ted flow reductions possible through utilization of these four methods are
shown in Table A-93.
Utilizing an 11 L/flush (3 gal/flush) toilet, a sudsaver washer, and a
57 L (15 gal) bath/shower, waste flow reductions of 7 to 23% were calculated
with an average of Y[% . Recycling the bath and laundry wastewaters for toilet
flushing could increase these reductions to 23 to h3% with an average of 33%.
It should be noted that these reductions were calculated assuming that the
number of events/cap/day remained unchanged after application of the water-
saving methods.
A comparison of these results with those of the previously discussed
studies indicated some disagreement as to the water savings and waste flow
reductions achievable through utilization of a particular device. This is as
expected, however, in light of the variation in water-use habits between indi-
viduals and homes. For example, if the residents of a given household prefer
baths for bathing, a flow-reducing showerhead will be of little value. Simi-
larly, a. low-flush toilet will not have as significant an effect for the
household where the residents are very mobile and tend to use restroom faci-
ties outside the home. Due to these types of user habit variations, it is
A-120
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A-121
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very difficult to accurately predict the actual waste flow reduction which may
result from use of a particular device in a given household. One must exercise
caution in applying the laboratory performance data or even limited field in-
formation for a given water-saving device to an "average" household water use,
to yield a particular flow reduction for a given household.
Waste Segregation
A second major technique for altering the characteristics of household
wastewater involves separating the toilet wastes ("black water) from the other
household wastewaters (grey waters) for separate treatment and disposal. This
segregation scheme also includes the elimination of the household garbage
disposal. The basis for suggesting this segregation lies in the characteris-
tics of the segregated waste streams.
The results of the characterization studies previously discussed in this
appendix demonstrated that the use of a garbage disposal can increase the
BOD;, and suspended solids loading in household wastewater by 22% to &k% and
1*3% to 9*$» while adding little flow, nitrogen or phosphorus (Table A-36) .
For this reason and the fact that most of the wastes handled by a garbage dis-
posal can be handled effectively as solid wastes, the garbage disposal was
eliminated as part of the segregation scheme.
The division of chemical/physical pollutants between the black water and
grey water, are shown in Table A-9^- On the average, the grey water contri-
butes about 65% of the flow, 10% of the phosphorus and 63$ of the BOD,-, while
the black water contributes about 6l% of the suspended solids, 82% of the
nitrogen and 31% of the BOD,-.
TABLE A-91*. BLACK AND GREY HOUSEHOLD WASTEWATER CHARACTERISTICS*
Pollutant
Grey Water
Black Water
Mean Range
Mean
g/c/d
Mean
mg/L
Mean Range
Mean Mean
g/c/d mg/L
63 51-80 28.5
255
37
20-1*9 16. T
280
Suspended
Solids
Nitrogen
Phosphorus
Flow
39
18
TO
65
23-61*
1-33
58-86
53-81
17.2 155
1.9 IT
2.8 25
111 L/cap/day
6l
82
30
35
36-TT
6T-99
ll*-l*2
19-1*7
27.0
8.7
1.2
1*50
ll*5
20
60 .L/cap/day
* Based on the results of studies by Olsson, Karlgren & Tullander, 1968;
Cohen & Wallman, 19T^; Ligman, Hutzler & Boyle, 19T^; Laak, 19T5; Bennett &
Linstedt, 19T5; and this study - garbage disposal results omitted.
A-122
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The microbiological characteristics of the two vaste streams, and in par-
ticular the grey water, are of prime importance. Both enteric and non-enteric
organisms are of interest, and the obvious concern is for the potential occur-
rence of pathogenic organisms in the grey and/or black water streams. Obvious-
ly, a prerequisite to encountering any pathogenic organisms in either waste
fraction is that a member of the household or visitor thereof, be shedding
pathogens. Unfortunately, data concerning the percentage of the population
shedding various potential pathogens is highly variable and, in many cases,
altogether lacking.
In regard to enteric organisms, samples of the effluents from septic
tanks receiving combined household wastewater have been found to consistently
contain significant concentrations of indicator bacteria and the potential
pathogen, Pseudomonas aeruginosa (McCoy and ZiebeH, 1976). Staphylococeus
aureus and salmonellae have also been isolated, but only infrequently and in
much lower concentrations (McCoy and Ziebell, 1976). Intuitively, one would
expect that the great majority of these organisms (predominantly enteric)
in combined household wastewaters are contributed in the toilet wastes, with
the grey water being comparatively less contaminated. The microbiological
studies conducted as a part of this project indicate that bath and laundry
wastewaters do possess a potential for yielding enteric contamination of the
grey water, possibly including enteric pathogens. However, the degree of
enteric contamination and the potential for encountering enteric pathogens in
the grey water appears significantly lower than that of either the black
water or combined household wastewater. Table A-95 illustrates this point.
In addition to the enteric organisms, non-enteric organisms such as
those discharged in sputum and washed from the skin, deserve attention. If
someone in a household were suffering from a respiratory or an external
TABLE A-95. ESTIMATED BACTERIOLOGICAL CHARACTERISTICS OF VARIOUS
HOUSEHOLD WASTEWATER STREAMS, organisms/100 mL
Effluent
Organism
Total Coli forms
Fecal Coliforms
Fecal Streptococci
Grey*
Water
1000
660
250
Toilet**
Wastewater
6,000,000
6,000,000
60,000
Combined1
Wastewater
2,100,000
2,100,000
21,000
Combine d+
Wastewater
Septic Tank
Effluent
3,^00,000
1*20,000
3,800
* Contribution of flow by bath and laundry approx. equal, average of means
for two events calculated, contribution of organisms by other household
events (kitchen sink, etc.) assumed equal to this average.
**Calculated assuming: 100 wet gm feces/cap/day and toilet flush flow of
60 L/cap/day with bacterial contents per wet gram of feces equal to,
total and fecal coliforms = 10? and fecal streptococci = 10^.
' Calculated: Value = .65 grey water value and .35 toilet wastes value.
+ McCoy and Ziebell, 1976.
A-123
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epidermal infection, the possibility would exist for the associated non-enteric
organisms to enter the grey wastewater stream. This is evidenced by the re-
sults of analyses on coliform and streptococcal isolates of bath and laundry
origin noted previously, which indicated that much of the bacterial contamina-
tion in the samples was from the natural environment or skin flora of man.
To assess the magnitude of this potential for encountering non-enteric organisms
in grey water and place it in perspective one has to consider the relative
importance of grey water, even without treatment, as a transmission route
compared to other routes, such as the vehicles, vectors and person-to-person
contact encountered in normal daily activities. Consideration of this factor,
as well as the added fact that many of the non-enteric organisms of concern are
ubiquitous opportunists would seem to indicate that in general, transmission
of non-enteric organisms through household grey waters is not of major concern.
Methods to Achieve Waste Segregation—
To provide for segregation and separate handling of the toilet wastes,
several alternatives to the conventional flush toilet have been proposed. In
a recent study, over a dozen alternative toilets were identified (Rybczynski
and Ortega, 1975). Those which have been receiving increased promotion and
attention include the composting, closed loop recycle, very low flush/holding
tank systems, and incinerating toilet systems.
Evaluations of Segregated Treatment Systems—
Very little research has been conducted on segregated treatment systems.
Obviously, waste segregation was an integral part of society for many years
for those utilizing the pit privy. However, only recently have actual inves-
tigations of segregated waste treatment been initiated. For the most part,
these investigations have been directed toward evaluation of the non-water
carriage toilet systems. Typically, grey water disposal has been accomplished
with a conventional septic tank-soil absorption system, possibly of reduced
size due to a reduced hydraulic loading. However, other more innovative
alternatives may be feasible due to the reduced pollutant load and contamina-
tion of the grey water.
Implications for Onsite Wastewater Disposal
Impact on the Operation of Existing Systems—
For an existing soil disposal system which is functioning satisfactorily,
reducing the wastewater flow volume or eliminating pollutants at the source
might serve to extend the life of the soil absorption system. However, by
what factor, if at all, is presently unknown. If the existing system were
failing, with wastewater daylighting or backing up, flow reduction efforts
could reduce the waste load sufficiently to remedy the situation. For those
establishments utilizing a holding tank system, waste flow reductions could
yield significant savings in pumping charges.
With regard to existing disposal systems, it is important to realize that
simple, relatively inexpensive waste flow reduction measures may yield signi-
ficant benefits, especially to those households which have disposal systems
which are hydraulicly overloaded. If a given technique or device does not
yield the expected reduction, in many cases little time, effort and money will
have been lost. If the objective was to remedy an overloaded system and waste
A-12U
-------
flow reduction techniques proved unsuccessful, alternative, more costly solu-
tions such as expanding or replacing the system, could then be tried.
Impact on the Design and Operation of New Systems—
Accounting for the altered waste loads provided by water conservation
practices can be a complex task. One must be relatively confident that the
use of a given device or system will yield a predicted waste load reduction.
Further, one must be confident that the technique or device utilized will
be accepted by the present users as well as future users and be used through-
out the service life of the disposal system. If a device or system does not
yield an expected reduction or is disconnected or replaced, the waste loads
to the onsite disposal system will be greater than expected, possibly resulting
in system failure. If this happens, remedial actions could be taken, including
upgrading or replacing the disposal system; however, this is often costly and
very difficult to accomplish. If modifications are permitted in the design
of an onsite waste disposal system due to an expected altered waste load, pro-
visions should be made for alternative waste disposal methods.
Simply reducing the waste flow volume to a conventional soil disposal
system should enable the size of the system to be reduced in proportion to
the expected reduced flow. However, any reduced sizing should probably be
restricted to the soil disposal field with any pretreatment process maintained
largely full-size to provide the necessary capacity to treat and attenuate
peak flows. In addition to a reduced flow, waste segregation practices provide
for a reduction in the quantity and concentration of certain pollutants, a fact
which has been suggested to render grey water more acceptable to soil absorp-
tion. However, efforts to correlate soil clogging with household wastewater
characteristics have been generally unsuccessful, especially in the more
problematic structured soils (Appendix B of this report). At present, any
reduction in field sizing should be based solely on a reduced hydraulic
loading.
Waste segregation practices appear to offer the potential to facilitate
alternative systems, including surface disposal, exterior reuse, or modified
subsurface disposal of household grey water. Detailed field investigations
are necessary to adequately evaluate this potential.
A-125
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PART 2
EVALUATION OF ONSITE WASTEWATER TREATMENT METHODS
INTRODUCTION
The choices available for wastewater disposal are numerous, yet only a
selected few will prove to be both economically and environmentally acceptable.
The selection process involves the evaluation of technical feasibility, cost
effectiveness and administrative feasibility. Table A-96 lists some of the
treatment processes potentially available for onsite treatment of wastewater.
This portion of the report will briefly review many of these processes and
subsequently discuss the results of laboratory and field experience with a
number of promising systems installed by the University of Wisconsin research
group.
TREATMENT METHODS
Biological Processes
Anaerobic Systems—
Anaerobic processes can be divided into two distinctive biochemical
groups, the fermentations and the anaerobic respirations. Fermentations are
defined as energy yielding metabolic processes in which organic compounds
serve as both electron donors and electron acceptors. With anaerobic respira-
tions, an oxidized inorganic compound such as nitrate, sulfate and carbonate,
serves as the ultimate electron acceptor. Both fermentations and anaerobic
respirations play an important role in waste treatment processes. In the
anaerobic environment, bacteria will normally attack organic molecules such
as lipids, cellulosic materials and proteins reducing them to a molecular size
which can be subsequently fermented (hydrolysis). A complex group of anaerobic
microbes will then ferment these molecules to acetate, other organic acids,
alcohols, H2, C02, NH3 and sulfide. A second, still rather unknown group of
bacteria convert the organic acids and alcohols to more acetate and H2.
Finally, a third group of diverse species of methanogenic bacteria which uti-
lize H2 and C02 and acetate will produce City and H2. This sequence of reac-
tions is most important in anaerobic treatment processes for it is the
generation of methane gas (and small amounts of C02 and H2) which result in
the reduction of BOD in the wastewater. Hydrolytic and fermentative reactions
up to the methanogenic step merely transform organic molecules but do not
result in removal of BOD. Since the methanogenic organisms are very sensitive
to environmental conditions, the effectiveness of anaerobic fermentative treat-
ment processes is dependent, to a great degree on process control.
A-12 6
-------
TABLE A-96. POTENTIAL WASTEWATER TREATMENT
PROCESSES - ONSITE DISPOSAL
Biological Processes
Anaerobic
Septic Tanks
Fixed Media Systems
Sand/Granular
Synthetic Media
Aerobic
Suspended Growth
Activated Sludge
Batch
Continuous Flow
Fixed Media
Sand-Intermittent Filter
Expanded Bed
Coarse Media
Trickling Filters
Rotating Biological Media
Tray/Media Contactors
Physical/Chemical Processes
Adsorption
Ion Exchange
Chemical Precipitation
Disinfection
Chlorine
Iodine
Ultraviolet
Ozone
The presence of sulfates, nitrates and other selected oxidized inorganics
in wastewater is also of importance in anaerobic systems. The anaerobic res-
piration of nitrate leading to the ultimate production of nitrogen gas is used
to achieve nitrogen removal in wastewater. The reduction of these oxidized
compounds also serve to produce a stabilization of BOD.
The kinetics of anaerobic processes are dependent upon the substrate
quality and quantity, the number and type of microbes and the environmental
conditions within the process. Theoretical growth rates of anaerobic organisms
are comparable to aerobes, but environmental conditions are often more critical
to optimum activity of the anaerobes. Thus, for optimal methane production,
no dissolved oxygen can be present, ORP values must be low, temperature ranges
are best between 32-37°C or 50-55°C, and pH should be maintained between 6.7
and 7.1*.
A-127
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In short, anaerobic treatment has many advantages that make it attractive
as a household wastewater treatment process. It requires no power input and
will continue with no attention from the homeowner. Biological growth is so
low that it is not necessary to remove sludge from the system very frequently.
The effluent produced, however, can be malodorous and high in pathogenic
organism indicators but, if disposed of in the subsurface soil, it need not be
a nuisance.
Household Units—
Septic tank-~The septic tank has been virtually the only means of treat-
ment employed prior to final disposal in household waste treatment systems.
Its design, installation, and operation is the simplest of all treatment
methods devised and it is also the least expensive. Its performance has been
in question because of the large number of failures in the attendant soil
absorption field, but when installed properly, the septic tank - soil absorption
system is one of the best methods of treatment and disposal for the single
home.
The primary purpose of the septic tank is to protect the soil absorption
field from becoming clogged by solids suspended in the raw wastewater. The
septic tank provides three functions to accomplish this goal. First, it acts
as a settling chamber to remove much of the settleable and floatable materials.
Second, it provides storage for the solids removed and an anaerobic environment
for their digestion by anaerobic organisms. The third function is the anaero-
bic treatment of the non-settleable particles to change their character from a
gelatinous nature to a non-gelatinous nature to reduce the clogging potential
of the solids remaining in suspension (Ludwig, 1950; Nottingham and Ludwig,
19H8).
Though simple in principle, there are certain design features that must
be included in every septic tank. The tank is generally sufficiently large to
provide a hydraulic detention time of at least 2U hours at the expected average
daily flow, after allowing two-thirds of the tank volume for sludge/scum storage.
Inlet baffles are generally installed to prevent short circuiting of the liquid
across the top of the tank and to mix the fresh sewage with the biologically
active liquid and sludge in the tank. The invert of the outlet should be at a
level sufficiently below the inlet invert to prevent backwater and stranding
of solids in the sewer line during momentary rises in the tank level when
wastewater is intermittently discharged from the home. Baffling of the outlet
or use of an outlet tee is required to prevent the scum from leaving with the
effluent. Venting through the house vent is necessary to allow the release of
gases produced. Depth and shape of the tank are generally specified within
limits to minimize any effect on treatment efficiency within reasonable limits.
Recommended capacities and dimensions can be found in the Manual of Septic Tank
Practice (1967) which incorporates many of the findings from a five-year study
of septic tank systems by the U.S. Public Health Service.
Many investigators have attempted to improve the quality of effluent pro-
duced by septic tanks and to reduce its variability. Their studies have re-
sulted in recommended design modifications which primarily reduce the amount
of suspended solids that are discharged in the effluent. Ludwig (1950) found
A-128
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elongated tanks with, length to width ratios of 3 to 1 and greater, retarded
short circuiting through the tank and improved suspended solids removal. He
and others have found that two or more tanks in series or a compartmentalized
tank provides better treatment (Ludwig, 191*9, 1950; Weibel, et al., 191*9, 195*0.
The Manual of Septic Tank Practice (1967) recommends a two compartment system
with the first compartment 1/2 to 2/3 the total volume. Each compartment must
be vented through the household plumbing and manholes provided for access.
Another modification is the gas deflection baffle (Baumann and Babbitt,
195*0. Rising gases from anaerobic metabolism within the sludge disturbs the
tank contents so that solids are resuspended and washed out of the tank. It
also appears that the tank "overturns" each spring and fall in response to
seasonal temperature changes, causing an increase in the concentration of
solids discharged. Conventional effluent baffles are unable to prevent this
washout.
Another concern of investigators has been the effect of household
chemicals on the biological treatment provided by the tank. All studies per-
formed indicate that detergents, soaps, bleaches, drain cleaners, water
softening brine and other such materials have no adverse effect as normally
used (Fuller, 1952; Truesdale and Mann, 1968; Weibel, 1955b). Septic tank
operation is not found to be improved and, in fact, may be harmed by the addi-
tion of disinfectants or other chemicals marketed for such purposes (Weibel,
1955b)• Enzyme additives have not proven beneficial. Generally, chemical
additions are not recommended.
Maintenance requirements for septic tanks are minimal but they must be
performed regularly to prevent the soil field from clogging. Once each year
the sludge and scum levels should be checked by a procedure similar to the
one outlined in the Manual of Septic Tank Practice (1967). If sludge or scum
accumulations are excessive, the tank should be pumped to remove them before
solids are discharged to the field. Anaerobic digestion of the sludge will
reduce the volume of accumulations, but a maximum of Uo percent reduction could
be anticipated under the most ideal conditions (Truesdale and Mann, 1968).
Nondegradable solids will accumulate and these must be removed. Generally it
is good practice to pump the tank once every three years dependent upon use.
Anaerobic contact tanks—Though some anaerobic treatment of the liquid
fraction of the waste occurs within the septic tank, the majority of the solu-
ble organics pass through the system because they are not brought into contact
with the anaerobic organisms. If the bacteria were mixed with the liquid in
some way, much better removals of BOD would be realized. This is known as the
anaerobic contact process.
The anaerobic contact process can take one of two forms. Either the
sludge can be anaerobically mixed with the waste which is analagous to the
activated sludge process, or the liquid can be passed through porous media
upon which the bacteria cling, the anaerobic counterpart to a trickling filter.
Both configurations have been investigated, but rarely applied to household
wastewater treatment.
A-129
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Coulter, et al., 1957, first proposed the anaerobic contact process on a
small scale for treating vastes from a small subdivision. Pilot plant studies
revealed that upflow of rav wastewater through the sludge blanket and use of
slow mixing to break up and disperse sludge solids produced BOD^ and suspended
solids removals of 50-65$ and Qh% respectively after l8 hours contact. Full
scale studies for an anaerobic contact system for a 350 home subdivision pro-
duced an average of 33.6% BOD[- removal and 76.8% removal of suspended solids.
The system was very stable and required little attention. The disadvantage of
this system was, primarily, its inability to handle hydraulic surges.
The anaerobic filter appears to be a more practical system for small
flows. Upflow of wastewater through a variety of porous media have proven
successful for treating wastewater (Young and McCarty, 1969; Jeris, 1975).
Such a filter has b'een tried in India, following septic tanks that re-
ceived toilet wastes only (Raman and Chakladar, 1972). It was designed for
loading rates slightly higher than a low rate trickling filter. An effluent
quality was sought that could be suitable for surface discharge where subsur-
face disposal was not possible. Three such systems of different configurations
were installed and compared. Two upflow and one downflow-upflow configurations
were tried. The total volume of each filter was 1/3 to lA the volume of the
septic tank served. Crushed brick and stone chips (1.3-2.0 cm) were used as
media to depths of 38 to 85 cm (1.25 to 2.75 ft).
The filters performed well at an application rate of U.I to 6.1 cm/d (l
to 1.5 gal/ft^/day). The filter effluent was free from odor, clear or trans-
lucent and had a light or pale yellow color. Results of the studies appear
in Table A-97..
TABLE A-97- RESULTS OF EFFLUENT ANALYSES FROM AN ANAEROBIC FILTER
FOLLOWING A SEPTIC TANK (Raman & Chakladar, 1972)
Waste
Fraction
BOD
SS
Turbidity
Septic Tank
Effluent Concentration
170 -
350 -
200 -
2UO mg/L
U50 mg/L
UOO JTU
Filter Effluent
Concentration
35 -
150 -
20 -
70 mg/L
190 mg/L
60 JTU
Percent
Removal
65
53
- 75$
- 60$
-
Clogging did occur with these filters after nearly two years of operation.
They were cleared by opening a plug in the distribution pipe to reverse the
direction of flow and flushing from the top with 56 liter (15 gal) of water.
A 2.5 to 15 cm (l to 6 in) headless was experienced throughout the runs.
Denitrification reactors—Biological denitrification has been extensively
evaluated as a means of removing nitrogen from municipal and industrial waste-
waters and irrigation return flows (Eliassen and Tchobanoglous, 1968; Tamblyn
and Sword, 1969; St. Amant and Beck, 1970; McCarty and Haug, 1971; Savage,
Francis and Callahan, 1975). This approach, when used with large scale
A-130
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accessible reactors, appears to be technically feasible and economically com-
petitive with other nitrogen removal methods.
B-ioenerget-Los of den-Ltrifloat-ion—The main gaseous N products from biolo-
gical denitrification of NO* and NO* are N~0 and N0 (Alexander, 1961). Ni-
trous oxide (N^O) is further reduced to N? in aqueous systems because of its
high water solubility and thus is not a significant end product in reactor
systems (McCarty and Haug, 1971)- The process is essentially a respiratory
mechanism in which N0~ or NO* replaces Cu as the terminal electron acceptor.
It is carried out by a wide variety of ubiquitous facultative heterotrophic
bacteria, and by certain autotrophs. It involves a change in the average
valence level of N from +5 (NO-*) to 0 (No). The precise pathway remains un-
clear, but NO* (N+3) and N20(+ 1) are definite intermediates. The reaction is
often written using CH~OH fmethanol) as the electron donor (eq. 21 to 23) .
NO" + 1/3CH3OH + NO" + 1/3C00 + 2/3H00 (21)
N0~ + 1/2CHJDH -*• 1/2N2 + 1/2C02 + 1/2H20 + OH* (22)
Sum:
NO" + 5/6CHOH -»• 1/2N + 5/6C00 + T/6H0 + OH" (23)
3 2
0
Thus, 1.9 g of CH,.OH are oxidized per g of NOo nitrogen. However, additional
CH-,OH (or any other available organic compound which is serving as an electron
donor) is needed to consume 02 (if present) and provide substrate for micro-
bial growth. About 30 to kQfo extra carbon substrate than theoretical is
usually required, providing the C substrate is soluble and readily available
(McCarty, et al., 1969).
Anoxic conditions are also a prerequisite for biological denitrification.
The pH and temperature of the system affects the rate of denitrification.
Most studies indicate optimal denitrification at temperatures between 20 and
25°C, and pH of 7 to 8 (Alexander, 196l; Broadbent and Clark, 1965). McCarty,
et al., (1969) evaluated acetone, methanol, ethanol and acetate as energy
sources, and found that the rates of denitrification were not appreciably
different from methanol provided sufficient time for acclimation to methanol
was permitted. More details on this process can be found in the U.S. EPA
Manual for Nitrogen Control (1975).
Dissimilatory nitrate removal can also be accomplished with the ubiquitous
chemolithotroph Thiobacillus denitrificans which is capable of oxidizing
elemental sulfur under anaerobic conditions, using nitrate as the electron
acceptor:
5S + 6KN03 + 2H2 0 -*- 3K2SOU + 2H2SO^ + 3N2 (2*0
If CaCO_ is used to buffer this system the reaction would be:
5S + 6KN03 + 2CaCO •> SKgSO^ + 2CaSO^ + 2C00 + 3N2 ' (25)
A-131
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Types of denitrifiaation reactors—Several types of biological denitrifi-
cation -units have been evaluated. These include modified activated sludge
units, packed bed reactors, anaerobic columns, and anaerobic ponds.
The modified activated sludge approach involves recycling of sludge from
a settling tank to maintain adequate bacterial populations (Francis and
Callahan, 1975). It is subject to several problems, including high rates of
assimilatory nitrate reduction (N0~ ->• organic N), long residence times, and
excessive washout of microbial biomass. Rotating biological discs can be
operated anaerobically, and appear to do an excellent job of denitrification
(Davies and Pretorius, 1975).
Packed bed or packed column reactors have been found to be quite suited
for biological denitrification. These units are enclosed reactors which con-
tain submerged inert packed material. Support materials have included sand,
gravel, coal, activated carbon, plexiglas, and polyethylene (Req.ua and
Schroeder, 1975; Savage, 197^; Davenport, et al., 1975; Francis and Callahan,
1975). Problems include high head loss, clogging and short circuiting. How-
ever, these can be overcome with proper design.
Erickson, et al. (1971), studied a system to remove N and P from livestock
wastes. This system used a limestone bed to remove P. Anaerobic conditions
were maintained in the bed, and molasses added as an energy source for deni-
trification. Their initial results were encouraging.
Kinetics—A number of steady-state kinetic models for denitrification
have been proposed (Francis and Callahan, 1975). These models assume suffi-
cient inorganic nutrients are present and that either the electron donor or
nitrate limits the growth rate. Monod (1950) kinetics have been found to
adequately describe the kinetics of nitrate removal (Req.ua and Schroeder,
1969), but requires valid estimates of biomass and concentrations at various
times, which is usually extremely difficult to obtain. Other kinetic models
which have been used include zero order (Doner, et al., 197*0 and first order
(Francis and Callahan, 1975).
Aerobic Systems—
The most efficient biological method of reducing the organic content of
dilute liquid waste is by aerobic treatment processes. Basically, the organ-
isms responsible for treatment possess the ability to decompose complex or-
ganic compounds and to use the energy liberated for reproduction and growth.
That part of the organic matter used to produce energy is converted to essen-
tially stable end products of carbon dioxide, water, and ammonia, while the
remainder is converted into new cells which are subsequently settled and
removed from the liquid before the waste is discharged into the receiving envi-
ronment. Oxygen must be continuously supplied during the aerobic process,
since it acts as the final electron acceptor for oxidation of organic matter.
It is during this electron transfer that there is liberation of large amounts
of energy used for the synthesis of new cells. The quantity of oxygen required
to stabilize organic matter depends on the organic content of the waste, and
the physiological condition of the organisms.
A-132
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In conventional aerobic treatment processes the synthesis of new "biolo-
gical growth can be expected to range "between 50 and 60$ of the dry weight of
organic matter fed to the unit. As the cell residence time increases, the
amount of cell material that is synthesized decreases. However, in no system
yet conceived is there a total reduction of sludge in the process owing to
the presence of inert material in the raw wastewater as well as to the synthe-
sis of non-degradable solids. Solids wasting schedules from aerobic processes
are dependent upon mass transfer capacity of the reactor as well as solids
handling capacity of the separator.
A wide variety of kinetic models have been developed for aerobic processes
in the treatment of wastewaters. The rates at which organic matter or other
substrates are stabilized in aerobic systems are dependent upon a number of
factors including the waste characteristics, pH, temperature, flow regime, and
presence of toxic materials. Monod (1950) kinetics have been found to ade-
quately describe the rates of most aerobic processes, although a number of
modifications of this kinetic model appear in the literature.
Several types of aerobic biological systems have been developed over the
past seventy years. These include suspended growth systems in which the micro-
bial cells are held in suspension and the organisms are in intimate contact
with the wastewater. Oxygen is normally transferred to the waste either
through diffused air or mechanical methods of gas transfer. The other major
type of biological system is made up of fixed film arrangements in which the
waste passes over a film of microorganisms attached to some type of media.
The media may pass through the waste, or the waste may pass over the media,
depending upon the system design.
Household Units—
Despite their advantageous treatment capabilities, use of aerobic pre-
treatment units in private home systems is generally discouraged by health
officials because of their high susceptibility to upsets. Without regular
supervision and maintenance, the aerobic unit may quickly lose its efficiency.
Since the homeowner cannot be relied upon to pump his septic tank regularly,
most health officials feel that the homeowner also would not perform the added
maintenance required by aerobic units (Voell and Vance, 197^; Waldorf, 1977).
To avoid this problem, manufacturers have tried several processes and
have incorporated various design features into the design of treatment units
in an attempt to reduce the need for constant surveillance. At least three
aerobic process flow schemes are presently on the market in the low flow waste
treatment field. They are extended aeration, trickling filtration, and rotating
biological disks. Each process has its own unique operational characteristics
and design features which must be employed to maintain a high effluent quality.
Extended Aeration—Extended aeration processes are modifications of the
activated sludge process employing long sludge ages and detention times. De-
tails of various process flowsheets used may be found in the literature (Na-
tional Sanitation Foundation, 1966; Howe, 196l; and Pillai, et al., 1971)-
It appears that extended aeration units are a good alternative to the
septic tank if certain operational problems could be solved. One of the major
A-133
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difficulties is periodic discharge of large amounts of solids caused by exces-
sive accumulation of mixed liquor solids, shock hydraulic loadings, and deni-
trification in the final clarifier (Howe, 196!; Filial, et al. , 1971; Reid,
1971; Bennett and Linstedt, 1975).
Other problems vhich frequently occur are inadequate control of the air
supply, foaming in the aeration tank, clogging of sludge return lines, exces-
sive solids return rates, and grease build-up (Howe, 1961). Therefore, care-
ful design and operation of these units are required to maintain a high quality
effluent. This is particularly true with units designed for the single house-
hold which must run for long periods of time with no attention while receiving
intermittent and highly variable waste flows.
A successful household waste treatment unit must produce and maintain a
high quality effluent regardless of changes in waste characteristics and flow,
yet, accomplish this with few mechanical parts and little operational attention.
A number of design features incorporated in extended aeration units are briefly
discussed below.
1. Process Flow—Continuous Versus Batch Operation
Continuous flow-through and fill-and-draw or batch operations are used
in household waste treatment units. The continuous flow-through units
discharge effluent continuously while receiving raw waste. The batch, on
the other hand, collects the raw waste over a period of time, treats it
throughout the holding period and discharges the treated waste only at
the end of the collection period. Advantages and disadvantages are given
in Table A-98.
2. Greases and Gross Solids Handling
Effective grease and gross solids handling is important in maintaining
overall treatment efficiency. If greases and inert objects are not re-
moved or broken up, they will accumulate in the system. Several handling
methods are employed including primary settling (septic tank), screens,
and "hydraulic comminutors" which rely on hydraulic turbulence to break
up large solids (Table A-99).
3. Final Clarification
The final clarification step determines the overall efficiency of the
unit. Since nearly complete stabilization of the influent BOD is achieved
through the plant, the effluent BOD is due primarily to suspended biolo-
gical solids which were not settled out.
Final clarification must provide effective liquid-solids separation,
effective sludge return, and floating solids removal. Both gravity
settling and filtration are employed. Gravity separation is most frequent-
ly used. Quiescent settling, upflow clarification, and plate settlers are
used together or separately in chambers following the aeration tank.
Solids separation by filtration may also be employed. The treated waste-
water passes through the filter prior to being discharged thereby retain-
ing the solids in the system. While filtration produces a superior
effluent it is very susceptible to clogging. Various separation techniques
are summarized in Table A-100-
-------
TABLE A-98. ADVANTAGES AND DISADVANTAGES TO PROCESS FLOW - EXTENDED AERATION
Process Flow
Advantages
Disadvantages
Continuous
Batch
1 .
2.
Can accept wastes at all
times
Requires fewer mechanical
parts
Prevents solids carry-
over from hydraulic surges
(except at pump out)
Prevents short circuiting
of waste
1. Hydraulic surges can scour
out sludge solids
2. Short circuiting of flow
possible
3. Uncontrolled, continuous
gravity discharge
1. Requires submersible pump
2. Should not accept wastes
during settling and pumping
unless a holding tank is
employed
3- Controlled pumped discharge
U. Requires no sludge return
facilities
TABLE A-99. ADVANTAGES AND DISADVANTAGES TO GREASE/
GROSS SOLIDS HANDLING - EXTENDED AERATION
Process
Advantages
Disadvantages
Primary
Settling
(Anaerobic
Chamber)
Screens
Hydrauli c
Comminutors
1. Removes and/or partially
degrades large objects
and solids before further
treatment
2. Removes and hydrolyses
greases
3. Increase total volume and
number of chambers of
treatment unit
k. Can be added to any unit
1. Removes large objects and
rags
2. Does not increase size and
cost of treatment unit
significantly
1. Breaks up large solids
for further treatment
2. Does not increase size and
cost of treatment unit
significantly
1.
2.
3.
1.
2.
Increases size and cost of
treatment unit
Offensive odors may be
released in aerobic process
Periodic pumping and dis-
posal of accumulated sludge
required
Requires frequent cleaning
and disposal of debris or
clogging will occur
Does not remove greases
Does not remove greases
Does not remove or break up
large inert objects
A-135
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TABLE A-100. ADVANTAGES AND DISADVANTAGES TO
SEPARATION PROCESSES - EXTENDED AERATION
Separation
Method
Advantages
Disadvantages
Gravity
Settling
(Batch)
Settling
Chambers
(Continuous
Flow)
Plate
Settlers
Upflow
1,
Filtration
Complete quiescence
during settling
No skimming of floating
solids or sludge return
facilities required
Simple and relatively
troublefree
Increased rate of settling
reducing discharges of
solids
Better solids removal
through sludge blanket
Superior solids removal
including floatables
»
No skimming of floating
-solids or sludge return
facilities required
Influent waste may enter,
disturbing settling phase
unless additional tank is
used
1. Floatables must be removed
ahead of unit
2. Energy from the aeration
chamber may be transferred
to the clarifier creating
turbulence and upset
1. Solids build up on plates
requiring frequent spraying
for cleaning
1. Sludge blanket very suscep-
tible to hydraulic shock
loading
2. Floatables must be removed
ahead of unit
1. Filter cloth clogging is
major problem
2. High head loss through
filter as it clogs
It-. Sludge Return
An effective sludge return is vital in providing biological seed for
the aerobic process. Air lift pumps, draft tubes working off the aerator
and gravity return methods are used. Batch processes or those that use
filters for the separation of solids require no provision for sludge
return. Rapid sludge removal from the final clarifier is beneficial to
prevent the development of anaerobic conditions which are ideal for
denitrifying bacteria. The resulting nitrogen gas produced from the
biological conversion of nitrate will float the sludge. Unless means
are provided for skimming these solids off and returning them to the
aeration tank they can be lost to the treatment process. Too rapid a
rate of sludge return, however, can increase the overflow rate of the
clarifier to the point where the sludge does not settle adequately.
A-136
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V
TABLE A-101.
ADVANTAGES AND DISADVANTAGES TO SLUDGE
RETURN METHOD - EXTENDED AERATION
Sludge Return
Method
Gravity
Air-lift
Pumps
Draft Tube
1.
1.
2.
1.
2.
Advantages
No mechanical parts 1.
Provides positive return 1.
Can be run off of air
supply for aeration
Provides positive sludge 1.
return
Can be activated by aerator
Disadvantages
Bridging of sludge may occur
May clog
May clog
Batch
Process
1. No mechanical parts
1. Solids may be pumped out if
sludge settles poorly or
sludge blanket is high due
to infrequent pumping
Floating sludge is ignored bv the majority of manufacturers. With
no means of return, solids carryrover can become a serious problem. If
the unit has not received wastewater for a long period of time while
under aeration, much of the sludge may float and be lost. Table A-101
compares sludge return systems.
Trickling filters—The trickling filter has been widely used in secondary
treatment of municipal wastes for many years. Its low cost of installation
and its relatively maintenance-free operation explain its popularity. How-
ever, it has rarely been considered for use as a household treatment system.
Although the effluent quality from a trickling filter is usually not as
good as that from an activated sludge process, the trickling filter is a very
attractive treatment method. Aerobic microorganisms are attached to the
filter media surfaces and not in the suspended state as in activated sludge.
This eliminates the need for mixing, a highly efficient final clarifier, and
sludge return facilities. It also makes the system less susceptible to upset.
Treatment efficiency drops during hydraulic surges but the biological solids
are less likely to be washed out of the system and therefore, recovery is
more immediate. Recovery from toxic shock loads is also rapid since only the
outermost organisms in the slime are usually affected. These advantages
would seem to make the system ideal for single household use.
The disadvantages, however, rule out the use of conventional trickling
filters for private systems. The large head requirement of the system
A-13T
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dictates deep excavation or pumping above ground structures. These are often
undesirable or impossible. Temperature effects on treatment are also great
and maintaining temperatures within the filter above those necessary for ef-
ficient treatment would be costly.
Three manufacturers, however, do market systems that closely resemble
trickling filters. All have modified the process to reduce the headlosses.
One manufacturer offers a horizontal folded filter with forced ventilation
while another uses a folded aeration tray following a septic tank. The third
drives the filter media through the wastewater on a chain-and-bucket__principal.
These modifications allow below ground construction which provides insulation
to reduce temperature effects.
Rotating biological disks—Rotating biological disk units are a series
of closely spaced disks mounted on a horizontal shaft such that they can be
slowly rotated through the wastewater while partially submerged. The disks
provide a large surface area for aerobic organisms to attach themselves and
grow as the disks are rotated. The constant rotation brings the organisms
into contact with both the wastewater and the atmosphere. When the growth
becomes too thick the biological solids are sloughed by the shearing action
created by the rotation.
Unlike the other processes discussed, very good control over the degree
of treatment is possible by placing several disk modules in series. As the
wastewater moves through the system, waste fractions are removed or partially
degraded to change the wastewater characteristics. The organisms which can
most efficiently utilize the substrate reaching them become dominant. If
constant flow is maintained through the use of a holding tank and feed mech-
anism, a succession of specialized organisms can result providing very effec-
tive and rapid treatment.
All the rotating disk units identified on the market today provide a
three-step process including pretreatment, biological stabilization on the
disk, and final clarification. Usually a septic tank provides the pretreat-
ment of the raw wastewater, but a first stage disk module can also be used to
create turbulence to break up the solids. In the latter case, a perforated
wall separates the first stage from the second stage. Greases and other
floatables also enter the second chamber.
The rotating disks provide secondary treatment. Treatment efficiency
depends on the number of stages, the hydraulic loading (L/m /d), residence
time, ratio of liquid volume to disk surface area in each stage, rotational
speed, and temperature (Autotrol Inc., 1972). Of these, only rotational speed
can be manipulated at the site. A wide variation of the other variables is
found among the units on the market and little data are available to allow
comparisons of the relative importance of each parameter in treatment effi-
ciency.
Final clarification occurs in settling or upflow sedimentation chambers.
Gravity sludge return is generally employed to recycle the settled solids for
further decomposition. Return can be made either to the primary or secondary
treatment chamber.
A-138
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The rotating disk process is relatively stable and efficient, and requires
little power or maintenance. The solids that are produced and sloughed are
generally dense and settle rapidly as in a trickling filter. Theoretically,
this system appears well suited to individual wastewater treatment, but opera-
tional experience is required.
Submerged biological media system—Submerged biological media systems are
similar to rotating disk units but rather than rotating the attached biological
growths through the wastewater, the wastewater is continuously aerated and
circulated through a submerged system of trays, tubes, or rocks. Aeration and
circulation may be provided by an air lift pump. In a system developed by
Klock (1973) several cells are put together to achieve a high degree of treat-
ment and stabilize the process. Because of the long solids retention time,
sludge production is kept at a minimum.- Another aerobic fixed media system
employs plastic rings fixed in a 0.58 m (20 cu ft) chamber (St. Louis Ship -
Ecodyne, 197*0. Mechanical aeration within this chamber circulates wastewater
through the media. The fixed bed chamber is preceded by a 3.7 m (130 cu ft)
tank contiguous with the fixed bed unit. This system, developed for shipboard
applications requires no gravity biological separation step and effluent is
discharged directly from the fixed media chamber.
Physical-Chemical Processes
In recent years, physical-chemical processes used to treat municipal and
industrial wastewaters have been given considerable attention because of in-
creasing demands for higher quality effluents. Periodic upsets which occur
in biological systems due to hydraulic surges, sudden changes in wastewater
characteristics, temperature effects, and other unpredictable phenomenon make
it very difficult to maintain a high quality effluent. The type of physical
or chemical process used depends upon the waste fraction to be removed. Table
A-102 presents a list of selected processes that potentially would be available
for low-flow waste treatment application.
TABLE A-102. SELECTED PHYSICAL-CHEMICAL PROCESSES
AND THE WASTE FRACTIONS REMOVED
Process Waste Fraction Removed
Primary Secondary
Coagulation/ Colloidal suspended solids, Some COD, BOD & POg
Precipitation and phosphorus bacteria and viruses
Filtration Suspended solids Suspended BOD, COD, P0j=
Possible nitrification
Carbon Dissolved COD, BOD Residual suspended solids
Adsorption
Ion Exchange Phosphorus, NH_, & total Specific ions depend upon
dissolved solids resins selected
A-139
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Because many of these processes are able to treat highly intermittent and
varying strength waste flows without upset, they should be well suited for
individual home use if the need for operation and maintenance is sufficiently
low. Several manufacturers market such units. Most of the units use the
physical-chemical processes as tertiary treatment steps following biological
treatment units but a few of the units do provide complete physical-chemical
treatment.
Chemical Coagulation and Precipitation—
Coagulation is a process in which chemicals are mixed with the wastewater
to form rapid settling solids from the colloidal and suspended particles that
cannot be removed through simple sedimentation because of their slow settling
velocities. With the proper chemicals, chemical precipitation from solution
of phosphorus and other compounds is also realized. Sedimentation follows
the chemical addition and flocculation to remove the resulting flocculent
solids.
In effective chemical processing of wastes, sufficient chemicals must be
added and mixed thoroughly with the wastewater at the proper time. The system
used to achieve this must be highly reliable, with little need for supervision
and maintenance. To provide the proper dose of chemicals,the wastewater volume
to be treated must be known. This can be done in two ways. The first is to
use the batch treatment process (Environment/One Corp., 1972). This requires
more mechanical equipment but provides excellent treatment. One method in-
volves the accumulation of the wastewater with aeration for mixing and aerobic
processing until the tank is filled to a preset volume. Raw waste is tempo-
rarily diverted into a holding tank while sufficient chemical is added and
mixed. Chemical addition is accomplished by a mechanical pump and mixing is
provided by aeration. After mixing, aeration is stopped and the tank acts as
a sedimentation chamber.
In continuous flow operations, other means of flow measurement must be
used. One such method developed by another manufacturer also employs the
batch principal, but on a smaller scale (Anticimexbolagen, 1971). After re-
ceiving biological treatment the wastewater flows into a dipper which, when
filled empties into a mixing cone before it is discharged to a sedimentation
tank. Each time the dipper tips, a preset amount of chemical is added. The
mixing cone is designed to provide sufficient turbulence to mix the chemical
and wastewater. Although nearly 30 cm of head is lost through this system, it
has the advantage of being completely driven hydraulically rather than by
mechanical means.
The selection of chemicals to be used involves many considerations. For
individual home units, iron salts are very corrosive chemicals, requiring
special materials for handling. Lime, though inexpensive and easy to handle,
requires an additional neutralization step prior to discharge. Alum is most
often used in household units.
Filtration—
Since most individual home filtration systems can be classified as inter-
mittent sand filters this discussion will be limited to this form of waste-
water filtration. Intermittent sand filtration may be defined as the inter-
A-lUO
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mittent application of raw or pretreated wastewater to an artificial or natural
bed of sand which is underdrained to collect and discharge the filter effluent.
Many intermittent sand filters are used throughout the United States to treat
and dispose of wastewater from motels, restaurants, trailer parks, service
stations and individual homes not served by a municipal wastewater system.
Sand filters are capable of purifying wastewater to a considerable degree
through mechanisms of straining, adsorption and biochemical oxidation. The
size of intermittent sand filters range from ten to several hundred m . Con-
struction is normally subsurface or covered in northern climates where
freezing is a problem while open surface filters are common in warmer climates.
The degree of purification attained by an intermittent sand filter is
dependent upon: (l) the type and biodegradability of wastewater applied to
the sand filter; (2) the environmental conditions within the sand filter; and
(3) the design characteristics of the sand filter. Generally, it has been
established that by increasing hydraulic loading rates to sand filters as the
quality of the applied wastewater increases, comparable sand filter effluent
qualities and length of time between filter clogging will be obtained.
Reaeration and temperature are two of the most important environmental
conditions that affect the degree of wastewater purification through a sand
filter. Availability of oxygen within the sand pores allows for the aerobic
decomposition of the wastewater. Temperature directly affects the rate of
microbial growth, chemical reactions, adsorption mechanisms and other factors
that contribute to the purification of wastewater within the sand media.
Proper selection of process design variables also aids in the purifica-
tion of wastewater by intermittent sand filters. A brief discussion of the
influence of these design variables on process performance is presented below.
Sand media—The successful use of sand as a filtering media is dependent
upon the proper choice of size, shape and uniformity of sand grains. Hazen
(1892) developed and defined two descriptive parameters to properly character-
ize a given filter sand. These parameters are the effective size and the uni-
formity coefficient. Both are obtained from a mechanical sieve analysis of a
representative sample of sand.
The effective size of the sand affects the quantity of wastewater that
may be filtered, the rate of filtration, the penetration depth of particulate
matter and the quality of the filter effluent. Sand that is too coarse lowers
the retention time of the applied wastewater in the filter to a point where
adequate biological decomposition is not attained. Too fine a sand limits
the quantity of wastewater that may be successfully filtered, due to the low
hydraulic capacity and the capillary saturation characteristic of fine sands.
Metcalf and Eddy (1935) and Boyce (1927) recommend that not more than 1% of
the sand should be finer than 0.13 mm. Many suggested values for the effec-
tive size.and uniformity coefficient exist in the literature. Table A-103
presents some of these recommended values. Most of these recommendations are
similar.
An excellent filter media consists almost entirely of siliceous sand.
Total organic matter in the sand should be less than 1% and total acid
A-lUl
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TABLE A-103.
RECOMMENDED SAND MEDIA CHARACTERISTICS
FOR TREATED SEPTIC SEWAGE
Manual of Septic Tank
Practice (196?)
Ten States Standards (i960)
ASCE Committee on Filtering
Materials (1937)
J. A. Salvato (1955)
Effective Size (mm)
0.25 to 0.6
0.1* to 1.0
0.2 to 0.5
0.25 to 0.5
Uniformity
Coefficient
Less than U.O
Less than 3.5
Less than 5.0
Less than U.O
soluble matter should not exceed 3%• Any clay, loam, limestone or other organic
material may increase the initial adsorption capacity of the sand but may lead
to a serious clogging condition as the filter ages.
Shapes of individual sand grains vary from round to angular configura-
tions. Purification of waste-water infiltrating through sand is dependent
upon the adsorption and oxidation of organic matter in the waste-water. To a
limiting extent this is dependent upon the shape of the grain size; however,
it is more dependent upon the size distribution of the sand grains which is
characterized by the uniformity coefficient.
The arrangement or placement of different sizes of sand grains throughout
the filter bed is also an important design consideration. Basically, there
are four major arrangements of different sand sizes:
1. a homogeneous bed of one effective size sand;
2. a non-homogeneous bed of pit run sand;
3. a bed having coarse sand layers above fine sand layers; and
U. a bed having fine sand layers above coarse sand layers.
A homogeneous bed of one effective size sand does not occur often in
practice. Numerous fine and coarse stratified layers of sand occur throughout
the bed due to construction practice, thus making it non-homogeneous. In a
bed having fine sand layers placed above coarse sand layers, the downward
attraction of wastewater is not as great due to the lower amount of cohesion
of the water in the larger pores (Clark and Gage, 1909).
The media arrangement of a coarse sand over a fine sand appears to be
the most favorable wastewater treatment process for at least two reasons:
(l) each coarse layer of sand is underdrained by a finer sand thus increasing
the downward pull of water due to the constantly increasing cohesion of the
sand layers, and (2) each succeeding finer layer of sand will strain and
mechanically remove finer particulate matter from the wastewater (Clark and
Gage, 1909). However, it may be difficult to operate such a filter due to
internal clogging of the filter.
A properly chosen sand media may be an excellent purifier of wastewater
by itself, but its combination with other filter media during construction
may seriously degrade its performance. Therefore, proper care must be taken
in the construction of the filter bed.
A-1U2
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Depths of intermittent sand filters were initially designed to be 120 to
305 cm (U to 10 ft), however, it was soon realized at the Lawrence Experi-
mental Station (Clark and Gage, 1909) that most of the purification of waste-
water occurred in the top 23 to 30 cm (9-12 in) of the bed. Additional bed
depth did help to improve the wastewater purification, but not to any signi-
ficant degree. Most sand depths used today range from 60 to 100 cm (2k to
k2 in). The use of shallow filter beds helps keep the cost of installation
low. Deeper sand beds tend to produce a more consistent effluent quality and
permit more sand cleaning operations before media replacement is required.
Loading rates and patterns—The hydraulic loading rate may be defined as
the volume of liquid applied to the surface area of the sand filter over a
designated length of time. Values of recommended loading rates for intermit-
tent sand filtration vary throughout the literature depending upon the effec-
tive sand size and the quality of influent wastewater. Figure A-3^ shows the
numerous hydraulic loading rates versus effective sand size employed for
previous intermittent sand filter studies.
Expressions of organic loading rates are not often found in the literature.
However, it was realized by early investigators that the performance of inter-
mittent sand filters was dependent upon the accumulation of stable organic
material in the filter bed (Clark and Gage, 1909; Schwartz, et al., 19&7).
To account for this, suggested hydraulic loading rates are often given for a
particular type of wastewater. Low loading rates are suggested for raw waste-
water with increasing loading rates suggested for primary septic tank and
secondary effluents.
Dosing techniques refer to methods of application of wastewater to the
sand filter. This is somewhat dependent upon whether the sand surface is
exposed or buried. Dosing methods that have been used include ridge and furrow
application, drain tile distribution, surface flooding, and a spray distribu-
tion method. Early sand filters for municipal wastewater were surface units
and normally employed ridge-furrow application or spray distributing methods.
Intermittent sand filters in use today for motels, restaurants, trailer parks,
and service stations are normally built below the soil surface and make use
of tile distribution. Installations where freezing is not a problem are now
being constructed with the surface of the filter exposed and distribution by
flooding of the sand surface. From the Cincinnati study (Schwartz, et al.,
1967)> surface flooding was found to be a simple distribution method that
produced high COD and coliform removals along with good nitrification.
The frequency of dosing intermittent sand filters is open to considerable
design judgment. Most of the earlier studies used one dose per day. The
Florida studies investigated multiple dosings and concluded that the BOD
removal efficiency of sands with effective sizes greater than 0.^5 mm is
appreciably increased when the frequency of loading is increased beyond twice
per day (Emerson, 19^5). This multiple dosing concept is being successfully
used in recirculating sand filter systems in Illinois (Hines and Favreau, 197^).
These installations use a sand media with effective size 0.6 to 1.0 mm and a
dosing frequency of 1 per 30 minutes.
A-1U3
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Performance characteristics—A critical summary of the literature examin-
ing the successful performance of intermittent sand filters is shown graphical-
ly in Figures A-35 through A-37 (Sauer, 1975). Hydraulic loading rate is
plotted versus effective size of sand for septic tank, primary settled and
secondary treated effluents. Percent BOD,- reduction and the length of time
between which maintenance is required to sustain continuous operation are the
dependent variables. Only sand bed depths greater than j6 cm (30 in) were
considered when plotting the graphs. Dosing frequencies of 1 per day, with
the exception of the Florida studies, were used predominantly in the literature
and, therefore, are used in the graphs. Uniformity coefficients of the sand
considered were less than 5.0 thus meeting acceptable media standards.
Due to the many different operating conditions for each intermittent
sand filter study, it is important to emphasize that the graphs only represent
trends demonstrated from previous studies.
Summary of recommended design from literature—The following statements
summarize the information found in the literature:
1. Wastewater passed through sands with effective size less than 0.20
mm is highly purified; however, sands of this size have low hydraulic
capacities and, therefore, require frequent maintenance at loading rates
greater than 6.1 cm/day (1.5 gpd/ft2).
2. A major portion of the literature studies were conducted with sands
with effective sizes -ranging from 0.20 to 0.50 mm and hydraulic loading
rates ranging from k.O to 2U.5 cm/day (l.O to 6.0 gpd/ft2).
3. The type and frequency of maintenance required to restore a clogged
sand filter bed to successful and continuous operation is not well estab-
lished in the literature. The required maintenance frequency recorded
on Figures A-35 through A-37 is based upon trends of sand filter failures
in the literature.
U. Only the Whitby, Ontario intermittent sand filter studies were
operated under flow conditions typical of individual households. These
subsurface sand filters were operated at U.1-6.1 cm/day (1.0-1.5 gpd/ft ).
5. Intermittent sand filters having sand media with effective size
greater than 0.20 mm and loaded at less than 6.1 cm/day (l.5 gpd/ft2) with
septic tank, primary settled or secondary treated wastewater require no
maintenance for at least 18 months.
6. A majority of the literature studies experienced a minimum BOD
reduction of 80$ through the sand filter for both septic tank and settled
wastewater influents.
7. The graph representing primary settled wastewater was generated al-
most entirely from data from the Florida study. The majority of these
experiments were conducted using multiple dosing techniques. Observation
of the graph, Figure A-37 shows that percent BOD reduction is less
dependent on hydraulic loading rate. From this, one might conclude that
A-1U5
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multiple dosing techniques reduces the dependency of BOD^ reduction on
hydraulic loading rate. This conclusion is substantiated in part by the
graph on septic tank treated waste-water. Sand filters represented by
this graph were dosed once per day, and it is apparent that percent BODc
reduction is not independent of hydraulic loading rate.
8. Intermittent sand filtration of secondary treated wastewater is not
well established in the literature as shown in Figure A-36.
Ion Exchange—
Ion exchange is a widely accepted method for the removal of inorganic
anions and cations from waters. Its use on an individual household basis is
well documented through the use of millions of cation exchangers for household
water softening and iron removal. In wastewater treatment, its primary use
has been in the removal of ammonia, and it also has been used for the removal
of heavy metal cations, anions of phosphate, nitrate, anionic metal ion com-
plexes and some organic molecules. A serious problem with the use of ion
exchange for treatment of wastes with substantial organic content is resin
binding caused by the organic matter. Prefiltering of waste or use of scaven-
ger resins has partially solved this problem (Applebaum, 1968). Both synthe-
tic and natural resins are employed in ion exchange applications. Reviews of
applications of ion exchange processes to wastewater can be found in Eliassen,
et al. (1965), Eliassen and Bennett (1967), Mercer, et al. (1970), and Weber
(1972).
In wastewater treatment, the removal of nitrogen as ammonia or possibly,
nitrate, employing ion exchange techniques has been successfully applied
(Battelle Northwest, 1969). The ion exchange resin normally employed is a
natural zeolite, Clinoptilolite. This naturally occurring resin is found in
the bentonite deposits of the Western U.S. It is a hydrated alumino-silicate
material of the general composition (MNo) 0 * Al«0 • mSiOg • nl^O where M and
N are the alkali metal and alkaline earth counter ions, respectively. Most
U.S. deposits are of the sodium form. The order of its selectivity is
+ + + +++++ + ++ +3 +3
Cs > Rb > K > NHj^ > Ba > Sr > Na > Ca > Fe > Al Mg > Li. A
detailed review of studies with Hector Clinoptilolite may be found in the
literature; Battelle Northwest (l97l), Mercer, et al. (1970), Koon and
Kaufman (1971), McLaren and Farquhar (1973), and Jorgensen, et al (1976).
ANAEROBIC/AEROBIC UNIT STUDIES
The objective of this phase of the Small Scale Waste Management Project
was to evaluate the present state-of-the-art in household wastewater treatment.
Included in this evaluation were conventional septic tanks, aerobic units, and
intermittent sand filters.
It is felt that the performance of any treatment system should be evalua-
ted according to the following criteria: (l) the average effluent quality
produced, (2) the variability in effluent quality, (3) the operating and
maintenance requirements, and (4) the total annual cost. If a system is to be
designed to produce a particular effluent quality, it is necessary to know the
capabilities and limitations of each component (e.g. septic tank, sand filter,
A-1U9
-------
etc.) of that system according to these four criteria. A unit may produce an
effluent of high average quality, but if it is highly variable and unpredict-
able, then the subsequent treatment and disposal methods must be chosen and
designed to handle these fluctuations. This leads to a more conservative
design and a more expensive system. A system with few mechanical parts is
also desirable to simplify maintenance and to prevent frequent breakdown.
This is important to improve reliability. The total annual costs are the
final criteria, including capital, installation, operation, and maintenance
costs. It is desirable to keep the cost at a minimum while still achieving
the necessary effluent quality.
Experimental Methods
Full-sized treatment units were installed at several locations throughout
the State of Wisconsin under both laboratory and field conditions (Table A-IO^).
A total of 11 septic tanks, 11 aerobic units (9 different manufacturers), 1
chemical unit and h sand filter units were evaluated. Unit installations
began in the Fall of 1971 with the last one being made during the Summer of
1975 (field site J).
Laboratory Investigations—
The laboratory investigations were conducted at two sites (site M from
January, 1973 to August, 1973 and site N from January, 1975 to March, 1976).
The primary objectives of the laboratory studies were to compare selected
treatment processes under controlled conditions, to identify critical design
features of these selected units, and to determine operation and maintenance
requirements.
Description of Installations—The unique feature of the laboratory
studies was the use of a specially designed wastewater simulator (Hutzler,
197*0 (see Attachment D for a detailed description of laboratory site N).
This simulation removed much of the home to home influent wastewater varia-
tion so that variations seen in effluent quality between units could be
attributed to variations within each process. Major household water-use
events were simulated through specially designed equipment and the resulting
wastewaters were directed to the various treatment units according to schedules
as outlined in Attachment D. The units were fed wastewaters generated to
simulate clotheswashing, dishwashing, kitchen wastes, garbage grinding, bathing,
showering, and toilet use. The flow rates and volumes of the various events
at each laboratory site are tabulated in Table A-105. Each process received
the same schedule of events; however, the starting times were staggered to
avoid duplication of the equipment. The schedule and strength of events were
selected on the basis of previous studies on the characterization of waste-
water (Ligman, 1972; Witt, 197^a; Siegrist, 1975). The monthly averages of
the influent wastewater characteristics were determined by measuring the
characteristics of the feed materials used and by keeping accurate records of
their utilization. The average values for sites M and N are listed in
Table A-106.
Typical treatment units were selected and installed at the two laboratory
sites (Table A-10U). Six treatment units were installed in an underground
sewage lift station (site M) and an additional 5 units were later installed
A-150
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TABLE A-105. INFLUENT CHARACTERISTICS
Laboratory Sites
Lab Site M Lab Site N
Event
T -Toilet
B -Bath
S -Shower
L -Laundry
DW-Dishwashing
K -Kitchen Waste
G -Garbage Grinding
Daily
Flow
Flow
(L/min)
57
75
9.5
60
7-5
11
11
-
Volume
of Event
(L)
11
95
95
150
55
8
15
-
Daily
Volume
(L)
165
95
95
150
110
15
30
660
(175 gpd)
Flow
(L/min)
57
1+0
11
60
7.5
11
-
-
Volume
of Event
(L)
15
87
87
185
57
Ik
-
-
Daily
Volume
(L)
195
87
iyU
185
57
U2
-
7^0
(195 gpd)
Volume in gallons = Volume in liters x 0.26U.
at site N (the batch aeration unit was moved from one site to the other). The
units at site M were: (l) a 2.3 cubic meter (6lO gal), single-chambered septic
tank; (2) a 1.0 cubic meter (260 gal) multi-chambered septic tank; (3) a 1.1
cubic meter (290 gallon), chemical addition and precipitation unit; (H) a U.5
cubic meter (1200 gal), extended aeration unit; (5) a 2.U cubic meter (660 gal),
batch aeration unit; and (6) a rotating disks module (23 m surface area) with
a 0.59 cubic meter (155 gal) clarifier. Space constraints at the lift station
precluded the installation of full-sized septic tanks. The rotating disk unit
consisted of a O.U8 m diameter module provided by the manufacturer and a rec-
tangular clarifier constructed by project personnel. The remaining units were
installed according to manufacturer specifications. Figure A-38 presents a
diagram of laboratory site M.
The treatment units installed at site N included: (l) a k.O cubic meter
(1000 gal) single-chambered septic tank; (2) a 2.0 cubic meter (500 gal) single-
chambered septic tank; (3) a 2.U cubic meter (660 gal) batch aeration unit
(from site M); (h) a 3.0 cubic meter (750 gal) extended aeration unit, (5) a
k.O cubic meter (1000 gal) submerged media unit; and (6) a 2.3 cubic meters
per day (6000 gpd) rotating disks unit (*A m2 surface area) installed with a
U.O cubic meter (1000 gal) septic tank. All the site N treatment units were
obtained from individual manufacturers; however, the rotating disks and the
submerged media units were considered as prototypes. The simulation program
was modified somewhat from site M as garbage grinding wastes were eliminated
and the waste strengths were altered upward. Wastewater was collected from
feeders simulating clotheswashing, dishwashing, kitchen sink wastes, bathing
and showering, and then directed to the various treatment units via an auto-
mated, rotating distributor (Figure A-39). Attachment D describes the labo-
ratory layout in much greater detail. The units were fed a daily flow of 0.7^
cubic meters per dav (196 gpd) which had the average characteristics summarized
A-152
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A-153
-------
EXTENDED
AERATION
WASTE
GENERATION
DISTRIBUTION
TREATMENT
BIOLOGICAL
DISK
Figure A-38. Laboratory flow sheet, lab site M.
in Table A-106. The monthly variations were due either to periodic malfunc-
tions of the feed equipment or to deliberate changes made to increase the
waste strength.
Effluents from the U cubic meter, septic tank and the extended aeration
unit at site W were used to load soil columns and columns representing sand
filters. Effluent from the submerged media unit was used to test an ultra-
violet irradiation unit.
Sampling—Effluents from all the laboratory units were flow-composited
at locations indicated on Figures A-38 and A-39 and collected semi-weekly for
analysis. The analyses included: BOD (filtered and unfiltered), COD, solids,
nitrogen forms and phosphorus forms and were performed according to Standard
Methods (1971). At the time of sample collection, additional samples of the
extended aeration and the batch aeration mixed liquors were taken to determine
solids content and the sludge volume index.
Miscellaneous—Operation and maintenance requirements were recorded in-
cluding power consumption, routine maintenance and periodic malfunctions.
Necessary repairs were made by project personnel with the assistance of
manufacturer representatives.
A-15U
-------
DISTRIBUTER
rv
(SUMP (I
^_^
DRAIN TO SEWER
o
o
0
0
o
o
o
0
o
o
0
o
o
o
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o
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AND EXTENDED
AERATION
EFFLUENTS
00
0 0
00
00
00
OO
00
O O
o o
o o
OO
o o
SAND
FILTERS
SOIL
COLUMNS
COMPOSITE
SAMPLE
TOILET
TANK
Figure A-39• Laboratory layout, lab site N.
Field Investigations—
The field investigations began during the Spring of 1972 with data being
collected at some installations up to the Spring of 1977. The objectives of
the field studies were to observe the installation and operation of treatment
units under actual field conditions, to determine the effluent quality of
septic tank, aerobic units and sand filters, and to obtain information on
operation and maintenance requirements (Otis and Boyle, 1976).
Description of installations—A total of ten installations were made at
private homes and on University experimental farms in Wisconsin (Table A-lQlt
and Figure A-4o). (See Tables A-13 and A-lit for details on family charac-
teristics for these homes.) The individual installations were made by local
A-155
-------
SITES A. B & D - Septic Tank-Mound over Slowly Permeable Soil
SITE C - Septic Tank - Aerobic Unit - Mound over Creviced Bedrock
?ITE E - Septic Tank - Sand Filter - Chlorination - Soil Absorption
I*fiH
f>
SITE F - Septic Tank - Mound over Creviced Bedrock
SITE G - Aerobic Unit - Shallow Trenches (Pressure Distribution)
FBI
SITE H - (Septic Tank) - Aerobic Unit - Sand Filter - Chlorination
Soil Absorption
n
y-g
-A.
SITE I - Aerobic Unit - Shallow Bed
SITE J - Septic Tank - Aerobic Unit - Sand Filters - UV Light -
Denitrification - Shallow Beds
T
Figure A-^0. Schematics of field installations.
A-156
-------
contractors with the assistance of project personnel. With the exception of
the rotating disks unit, all the treatment units (septic tanks and aerobic
units) vere typical of designs commercially available at the time of selection.
The sand filters were specially designed to receive application rates of
up to 0.!* nH/m2d (10 gpd/ft2). The surface area of the filters was approxi-
mately 1.5 square meters (l6 ft ) with sand depths ranging from 0.6 to 0.9
meters (2 to 3 ft). Two of the sand filter units received septic tank effluent
while the other two followed aerobic units.
Sampling—Twenty-four hour flow composited samples were collected monthly
or semi-monthly by automatic sampling devices from each step in the treatment
process. These were analyzed for filtered and unfiltered 5-day biochemical oxygen
demand (BOD^), chemical oxygen demand (COD), solids, total nitrogen (including
organic, ammonia and nitrite-nitrate nitrogen), phosphorus, total and fecal
coliforms, and fecal streptococcus according to Standard Methods, 13th edition
(1971). Temperature and pH were measured at the time of sample collection.
Operation and maintenance requirements were also recorded including power
consumption and routine maintenance. Necessary repairs of the treatment units
were made by local firms, and the costs were recorded. Sand filter operation
and maintenance was performed by project personnel. The periods over which
data were collected appears in Table A-107-
Data Analysis—
All of the effluent quality data (field and laboratory) were cataloged
and analyzed statistically by computer. Tests were made to determine whether
the data were distributed either normally or log-normally. In the case of the
field data, this determination was made on the basis of the coefficient of
skewness while the laboratory data were plotted as histograms and the decision
was made by visual observation. The mean, the 95$ confidence interval of the
mean, and the coefficient of variation were estimated for each parameter based
upon the appropriate distribution.
The performance of each unit was measured by the mean and coefficient of
variation of each selected parameter. The coefficient of variation is obtained
by dividing the standard deviation of the data by the mean (for data distributed
log-normally, the coefficient of variation is obtained by dividing the standard
deviation of the logarithms of the data by the mean of the logarithms). Smaller
coefficients of variation generally indicate greater stability. The 95$ con-
fidence intervals of the mean for a selected parameter are used to indicate
whether or not a significant difference exists between the effluent quality of
the various treatment units. An overlap of the intervals indicates that no
significant difference exists at the 95$ confidence level.
Treatment Unit Results
Data on the operation and maintenance and on the effluent quality of the
various treatment units were collected over a five year period (1972-1976) and
are summarized herein. In general, the period of operation for a particular
unit was greater than the period of effluent sampling, with start-up periods
being eliminated from the statistical analyses. All malfunctions occurring
during the period of operation were noted.
A-157
-------
TABLE A-10T. PERIODS OF DATA COLLECTION AT FIELD SITES
Site
A
B
C
D
E
F
G
H
I
J
Family*
Unit
B
E
D
J
K
H
F
C
c'
G
-
I
Water Use
Study
(Witt, 197*0
Summer 1973,
lU days
Summer 1973,
28 days
Autumn 1973,
1*2 days
Summer/Winter
1973-197^
68 days
Summer/Winter
1973-197^
62 days
Autumn 1973,
2U days
Winter 197^,
28 days
Summer/Winter
1973-197^,
77 days
-
Winter 1973-
197^,
35 days
-
Winter 1973-
197^
28 days
Wastevater
Character! zation
(Siegrist, 1975)
-
-
-
"
*"*
-
-
Spring 1971*
Summer 197^
Spring/ Summer
197^
-
Spring/ Summer
197^
Treatment
Unit
Effluent
May 1972-
May 197^
May 1972-
May 197^
July 1972-
June 197^
Aug. 1972-
June 197U
Oct. 1972-
Dec. 1976
Nov. 1972-
June 197^
Nov. 1972-
June 1971*
Aug. 1973-
May 197^
June 197^-
Dec. 1976
-
Mar. 1975-
Dec. 1976
Sand Filter
Effluent
-
-
-
"
Sept. 1973-
Dec. 1976
— ,
-
Sept. 1973-
May 197^
June 197^-
Dec. 1976
-
June 1976-
Dec. 1976
* Designation used in Part 1; See Tables A-13 and A-
A-158
-------
Laboratory Installations—
Operation—The treatment units installed at the laboratory sites M and TT
are compared as to their components, normal operation, power consumption,
oxygen transfer efficiencies and malfunctions in Tables A-108 and A-109.
There was a vast range in complexity of processes from the rather simple oper-
ation of the septic tanks to the complex, mechanical operation of the rotating
disks unit at site N. The processes are also differentiated in terms of their
mechanical components, flow character, primary biological state (aerobic or
anaerobic), solids separation and return, and time cycles of operation. Some
units included a pretreatment step (extended aeration and chemical addition at
site M; batch aeration and rotating disks at site N) which acted to remove
gross solids prior to the process treatment.
All the aerobic units were capable of providing sufficient aeration;
however, the oxygen transfer efficiencies (kilograms of oxygen transferred per
kilowatt-hour of power supplied) varied considerably. The rotating disk unit
(site N) had the lowest efficiency while the batch aeration had the highest.
Power consumption ranged from 2.U (rotating disks - site N) to 7-^ kilowatt-
hours per day (extended aeration - site N). Some manufacturers have tried to
reduce power consumption by either reducing the size of the aerator motor
(rotating disks - site N) or by providing an electrical timer for intermittent
operation (extended aeration - site M).
Some units were equipped with flow equalization equipment in an effort to
reduce effluent variability. The most controlled discharge occurred with the
batch aeration unit where the effluent is pumped out at a constant rate after
a preset settling period. The flow rate through the rotating disks module
(site N) was set at a constant O.l8 cubic meters per day (^90 gpd) by a special
pump arrangement. With other units, the effluent flow rate was directly
affected by the influent flow rate. Several of the laboratory units were
monitored as to their effluent flow in response to influent flows. Figure A-W-
shows the variation in effluent flow in response to the set schedule of events
at laboratory site N. The rotating disks produced the lowest flow variation
while the submerged media process had the greatest. More detailed information
on these responses is presented in Figures A-^2 and A-^3. In those tanks
not equipped with flow dampening devices (e.g. the septic tank and the sub-
merged media unit), the effluent flow response is a function of two factors,
tank surface area and inlet/outlet configuration.
The treatment units varied considerably in the method used for solids
separation and solids return. For example, the septic tank is primarily de-
signed as a solids settling and scum floatation process but it is also used
for solids decomposition. There was noticeable gas production from the septic
tanks but no attempt was made to quantify or determine its composition. This
gas production caused a portion of the decomposing solids to float to the
surface where they became part of the scum layer. The batch aeration process
probably had the most positive method of solids return since aeration and
settling occurred in the same chamber. A primary concern with this process is
the possibility of influent flow during effluent pump-out; however, since pump-
out is normally scheduled for sleeping hours, this is not a likely occurrence.
A-159
-------
TABLE A-108. PROCESS COMPARISONS - OPERATION AND MAINTENANCE
LABORATORY SITE M
TREATMENT
PROCESS
Sketch
of
Primary
Biological State
Mechanical
Components
Volume
Flow
Character
Solids
Separation
Time
Cycle
Period
of Operation
Measured Power
Consumption
Power Input/Voli
Oxygen Transfer
Efficiency
Required Routine
Maintenance
Malfunctions
SEPTIC
TANK
y- ,
]
Anaerobic
Decomposition
None
2.3 m3
Continuous Flow
Gravity Settling,
Scum Floatation
None
August 1972-
September 1973
None
-
-
Solids Removal
None
CHEMICAL
ADDITION
| 1
~~n "\y\
dL -^~
a
Anaerobic
Decomposition
Tipping Bucket,
Float Valve
Septic Tank -
1.0 m3
Clarifier -
1.1 m3
Continuous ,
Chemical Addi-
tion Metered By
Tipping Bucket
Gravity Settling,
Scum Floatation,
Chemical Precipi-
tation
Chemclal Metered
Proportional to
Flow
October 1972-
September 1973
None - Requires
About 0.7 kg of
AlS04/d
-
-
Solids Removal,
Chemcial Replen-
ishment
Float Valve
Clogged, Float
Valve Failed,
Tipper Bucket
Unbalanced
EXTENDED
AERATION
n
-1 -«T \ \\-
' oV \ 7
= v
I — 1
1 1
Aerobic ,
Suspended Growth
Aerator Motor,
Timer Controlled
Alarm
4.5 m3
(1.7 - 2.2 - 0.6)
Continuous Flow
Gravity Settling,
Scum Floatation,
Upflow Clarifier
Aerator ON 20
min, OFF 10 min
May 1972-
September 1973
3 kwh/d
(Aerator A-2.8)
(Aerator B-3.2)
.04 kw/m3
Aerator A - 0.13
kg 02 /kwh
Aerator B - Q.27
Solids Removal
Timer Corroded,
Shaft Fell Off
Aerator Shortly
After Installa-
tion
BATCH
AERATION
P
-»
0 8 * r-I
0 0 °S
Aerobic,
Suspended Growth
Air Compressor,
Submersible Pump,
Timer Controlled,
Alarm
Variable, 1.2 to
2.6 m3
Batch Discharge
Aeration and
Settling Occur
Ln Same
Chamber
Aerator ON 20 hr,
OFF 4 hr, Pump-
Out After 3% hr
of Settling
February 1972-
September 1973
6.3 kwh/d
0.17 kw/m3
0.48 to 0.65
kg O2 /kwh
Solids Removal
Control Panel
Problems
ROTATING
DISKS
/*r\
-VVxi 1*
^ uT_j "
Aerobic,
Attached Growth
Gear Motor,
Chain Drive
0.19 m3 disks i
0.8 m3 - disks
plus Clarifier
Slightly Equal-
ized, Received
Flow From
Septic Tank
Gravity Settling
None
December 1972-
September 1973
3.8 kwh/d
0.83 kw/m3
Not Determined
Solids Removal,
Parts Lubri-
cation
Chain Corroded
A-160
-------
TABLE A-109.
PROCESS COMPARISONS - OPERATION AND MAINTENANCE
LABORATORY SITE N
TREATMENT
PROCESS
Sketch
of
Primary
Biological State
Mechanical
Components
Volume
Flow
Character
Solids
Separation
Time
Cycle
Period
of Operation
Measured Power
Consumption
Power Input/Vol.
Oxygen Transfer
Efficiency
Required Routine
Maintenance
Malfunctions
SEPTIC
TANK
— - _
Anaerobic
Decomposition
None
4.0 m3
Continuous
Flow
Gravity Settling]
Scum Floatation
None
September 1974-
April 1977
None
—
—
Solids Removal
None
EXTENDED
AERATION
~ ; S ^7-~
os ! V
o o |
L J
Aerobic ,
Suspended Growth
Air Compressor,
Automatic Valve,
Timer Controlled
Alarm
Variable 2,7 to
3.1 m3
Equalized by Air
Lift Pump
Plate Settlers,
Air Lift Sludge
Return
Air Lift Sludge
Back to Aeration
Twice A Day
September 1974-
Aprll 1976
7.4 kwh/d
0.11 kw/m3
0.11 kg 02 /kwh
Solids Removal,
Parts Lubrica-
tion, Unit
C leaning
Valve Failed, Air
Line to Air Lift
Frequently
Clogged, Coupling
Between Motor and
Blower Wore Out
BATCH
AERATION
, r
—
0 & °rl
o o o
Aerobic ,
Suspended Growth
Air Compressor,
Submersible Pump,
Time Controlled,
Alarm
Variable 3.2 to
4.6 mi includes
2.0 m septic
tank
Batch Discharge
Aeration and
Settling Occur
In Same Chamber
Aerator ON 20 hr,
OFF 4 hr, Pump-
OtlT After 3h hr
of Settling
September 1974-
January 1976
6.3 kwh/d
.17 kw/m3
0.48 to 0.65
kg 02 /kwh
Solids Removal
Pump Failed,
Dlff users
C logged, Dif-
fusers Deter-
iorated
ROTATING
DISKS
=-=r~
v
T
b
Aerobic,
Attached Growth
Gear Motor Pump,
Dump Valve,
Timer Controlled,
Alarm
Disk Module- 0.24
Septic Tank -
2.0 to 3.7 m3
Equalized Constant
Flow Thru Disks
Upflow Clarlfier,
Contents Re-
turned to Septic
Tank Daily
Dump Valve Opens
Once per Day
September 1974-
November 1975
2.4 kwh/d
.42 kw/m3
0.061 kg 02 /kwh
Solids Removal,
Parts Lubrica-
tion, Unit
C leaning
Pump Clogged,
Pump Failed,
Shaft Broke,
Alarm Shorted
Out, Disks
Module Became
Ung lurd
SUBMERGED
MEDIA
~~*" ••"
BV
^ |
L 1
Aerobic,
Attached Growth
Aerator Motor
Media - .57 m3
Total Tank = 3,8
Continuous Flow*
Reclrculatlon
Thru Media
Solids Sloughing
Off Media Re-
turns to Quie-
scent ?one by
Gravity
None
September 1974-
Aprll 1976
3.9 kwh/d
.28 kw/m3
Not Determined
Solids Removal
None
A-l6l
-------
FLOW
RATE
4
3
2
5'
ZO
1 1 1 1 1
MINUTE _
mow
L I0
~ K
-|»
" 310
5
|l || SEPTIC TANK I
-.11 '•' \
fv-^J V_^J VAJ^_^^ j~Jt\
. ii EXTENDED AERATION
^ J'^~ 1* A~-^_^_^_ . ,
11 If SUBMERGED
•jJLJL.""
Jv__M V — ___J Wv_ . . _ _
- 5|" ROTATING DISKS
-
Lx :
i i i i
a'.
TSTKTL T LKTT
11 n | 111—i _ i j—iii i
SCHEDULE OF EVENTS
TT
i
yr yni j
T
i
10
N 2
HOUR OF DAY
10
Figure A-Ul. Flow variations of treatment unit
effluents, laboratory site N.
20
Ul
i is
K
bl
0.
^ 10
IS
Zj
5
Q
6
5
bi
K
1«
at
UJ
:•
"I
<2
-
1
i I :
1
!
°\
\
*
.
o\\
\
r SUBMERGED
MEDIA
ol LAB SITE N
I 1974
S
M INFLUENT FLOW -TWO 45 I/MIN DISCHARGES
1 FOR l-i- MIN EACH
l\
0 !\ .SEPTIC TANK
\\r
fOo^ / EXTENDED AERATION
/ ^nc-ZN^A A_XL A
A— ^35 ^*D»_^^^ <->— — — — -_____
x *•• *^_^^<^ ^™ ^™™o
^f 1 1 ^— OH 1 1 1 1 1
0 10 20 90 40 50 60 70 80 9
TIME FROM START OF WASH DISCHARGE (MINUTES)
Figure A-ii2 . Effluent flow response upon receiving a simulated
clotheswasher discharge, laboratory site N,
A-162
-------
30 r
25 -
w 20 -
3
ui 15
10-
7
6
Z
a.
- 3
•J
(9 2
PL J
Dl
1 | LAB SITE N
- i 1974
1
i
{? L — SUBMERGED
HI MEDIA
IP
III INFLUENT FLOW -49 l/ffl FOR 2 MIN
I \ -
1 |V SEPTIC TANK
1 |°'-^^Q-: i i i i
0 10 20 30 40 SO «0 70
TIME FROM START OF DISCHARGE ( MINUTES)
a. Bath discharge.
" 15
3
UJ 10
Q.
UJ
3
O
LAB SITE N
1974
EXTENDED AERATION
T^ -- BT — — A |
0 10 20 30 40 50 60 70
TIME FROM START OF DISCHARGE (MINUTES)
b. Shower discharge.
Figure A-^3. Effluent flow response upon receiving a simulated bath and
shower discharge, laboratory site N, 197^-
A-163
-------
The extended aeratipn unit at site N was designed especially to achieve
positive solids separation and return. Not only did it dampen flow peaks to
the clarifier but the clarifier was equipped with plate settlers and a posi-
tive, air-lift pumped solids return. Other configurations studied included
upflow clarifiers and gravity sludge return. The contents of the rotating
disks unit clarifier (site N) were automatically returned to the septic tank
on a daily basis by the use of a preset timing valve.
Finally, the submerged media system employed no clarification step.
Solids in the waste apparently adhered to the solid media and through circu-
lation patterns set up in the unit by the mechanical aerator, sloughed solids
moved downward into the holding tank below and adjacent to the media section.
Malfunctions—With the exceptions of the extended aeration unit at site M
and the submerged media unit at site N, all the aerobic units experienced some
type of malfunctioning which adversely affected effluent quality. The most
serious malfunctioning occurred with the rotating disk unit (site N) . Four
mechanical failures (broken shaft, electrical short and pump failure twice)
occurred within a one-year period. In addition, the pump clogged twice, the
dump valve clogged once and the first stage of plastic disks became completely
unglued. When properly operating, this unit was capable of producing a high
quality effluent in terms of BOD,- and suspended solids; however, these mechan-
ical breakdowns caused the unit to revert to a septic tank-type of treatment.
The extended aeration unit at site N also experienced several malfunctions
which seriously affected effluent quality. The most serious problem was a
frequent plugging of the air lift line that pumped mixed liquor from the aera-
tion chamber to the settling chamber. The hydraulics of the unit were such
that this prevented adequate sludge return to the aeration tank, and, as a
result, high amounts of solids were washed out of the unit. The only mechani-
cal failure for this unit was with the automatic valve which controlled the
air lift pumps, again resulting in a loss of solids in the effluent. Thus,
the improved solids separation method designed into the unit was ineffective
due to equipment malfunctions.
Other malfunctions in the laboratory included a pump failure with the
batch aeration unit (site N), corrosion problems with the rotating disks and
the extended aeration units at site M and float valve problems with the chemi-
cal addition unit (site M) . Most of the problems with the chemical addition
unit were involved with the inability to accurately feed alum at a constant
rate. The only advantage of this type of unit was its ability to remove sub-
stantial amounts of phosphorus compared to the purely biological processes.
Maintenance—A periodic removal of solids from the treatment unit was the
most common maintenance need. None of the laboratory septic tanks were
operated long enough (19 months was maximum period of operation) to require
sludge pumping. The submerged media unit (19 months), the rotating disks unit
at site N (15 months), and the extended aeration unit at site M (13 months)
also required no solids removal. The chemical addition unit required pumping
after 9 months of operation. The average sludge production was about 0.1
kilograms per cubic meter of wastewater.
A-16U
-------
The batch aeration unit at site M demonstrated a gradual build-up of sus-
pended solids under aeration (from about 3000 mg/L to 6000 mg/L over a 5 month
period) but a premature vashout of these solids prevented an accurate calcula-
tion of the sludge production. At site N, the batch unit was preceded by a
septic tank so the build-up of solids was much more gradual (only 6 grams per
cubic meter of wastewater treated). The mixed liquor suspended solids reached
a level of kkOO mg/L after 16 months of operation. The sludge volume index
(SVI) ranged from 60 near the end of testing to 360 near the beginning of
testing.
The suspended solids content of the extended aeration unit at site N
built up steadily (0.07 kilograms per cubic meter of wastewater) until it
began malfunctioning and the solids began washing out. The solids level at
this time was about 7500 mg/L. The SVI fluctuated between 60 and 120 during
the period of testing. The manufacturer suggested pumping the aeration tank
when the solids level reached 9000 mg/L as estimated by an Imhoff cone settling
test. This level was not attained during this study.
The primary routine maintenance necessary with the chemical addition unit
was the replacement of the aluminum sulfate solution (the manufacturer recom-
mended adding 1.5 L of 50$ alum solution per m3 wastewater). This requirement
necessitates either a large chemical storage tank or more frequent site visits
(for example, at site M, about 30 L of alum were used per month for a flow of
0.66 m3/day).
Other routine maintenance generally fell into two categories, parts
lubrication and unit cleaning. Only the rotating disks units (both sites) and
the extended aeration unit (site w) required periodic lubrication, about 1 or
2 times per year. The remaining mechanical units were equipped with factory
sealed bearings. The manufacturers of the extended aeration unit (site N) and
the rotating disks units were the only ones to recommend periodic cleaning as
part of their maintenance plan. Other manufacturers recommended periodic in-
spection to ensure the satisfactory operation of the mechanical components.
Unit cleaning involved the removal of any floating debris and washing of the
clarifier walls to remove solids adhering to them. The recommended frequency
of maintenance was every 3 months for the extended aeration unit and every 6
months for the rotating disks units.
Effluent quality and variability—The effluent quality data from the lab
units are summarized in Tables A-110 and A-lll. Because the wastewater was
simulated, caution should be used in interpreting the actual numbers. The
values for the different parameters between the various units should be used
for comparison only.
The following observations can be made concerning the effluent data ob-
tained at laboratory site M (Table A-110):
1. The aerobic units produced effluents with significantly lower levels
of BOD , COD and suspended solids than the septic tank effluents (on the
basis of 95$ confidence intervals).
A-165
-------
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