January 1976


The monitoring volume of this manual was prepared

for the U. S. Environmental  Protection Agency,

Office of Solid Waste -Management Programs, by

Wehran Engineering Corporation, Mlddletown, N, Y.

and Geraghty & Miller, Inc., Port Washington, N. Y,

                    TABLE OF CONTENTS

   1.                 INTRODUCTION
   2.                 EXECUTIVE SUMMARY
                      (In Progress)

   3.                 FUNDAMENTALS OF LEACHATE
                     3.1   Introduction
                     3.2   Origin, Composition and Fate of Leachate
                       .1  Refuse Zone
                       .2  Unsaturated Zone
                       .3  Aquifer Zone
                       .4  Measurement of Attenuation
                     3.3   Leachate Quantity

   4.                 MONITORING NETWORKS
                     4.1   Monitoring Networks
                       .1  Intergranular Porosity
                       .2  Fracture Porosity
                       .3  Solution Porosity
                     4.2   Leachate Movement in Different Hydrogeologic

                     5.1   Monitoring Techniques
                       .1  Zone of Aeration (Soil Water)
                       .2  Soil Sample Analysis
                       .3  Suction Lysimeters
                       .4  Trench Lysimeters

                     5.2   Zone of Saturation (Ground Water)
                       .1  Wells Screened Over a Single Vertical Interval
                       .2  Piezometers
                       .3  Well Clusters
                       .4  Single Well/Multiple Sampling Points
                       .5  Sampling During Drilling
                       .6  Pore Water Extraction From Core Samples

                     5.3   Other
                           Field Inspection
                           Surface Water Quality Measurements
                           Vegetation Stress
                           Measurement of Conductivity and Temperature

                         5.3 (Continued)
                                Seismac Surveys
                                Earth Resistivity  Survey
                                Geophysical Well Logging
                                Landfill Gas Measurements
                                Aerial Photography
                                Water Balance Analysis

                         5.4   Well Technology
                                Drilling Technology
                                Well Casing and  Screen  Materials
                                Well Security
                                Water Withdrawal Methods
   6.                    INDICATORS OF LEACHATE
                         6.1   Introduction
                         6.2   Background Quality  of  the  Ground  Water
                            .1  Chemical Quality of Natural Ground  Water
                            .2  Other Sources of Ground-Water  Contamination

                         6.3   Chemical, Phusical  and Biological Indicators

                         6.4   Indicator Groups
                            .1  Specific Conductance  Measurements
                            .2  Key Indicator Analyses Group
                            .3  Extended Indicator Analyses Group

                         6.5   Guidelines for Using Indicators
                            .1  Background Water Quality  Monitoring
                            1.1 New Land Disposal  Site
                            1.2 Existing Land Disposal Site
                            .2  On-Going Monitoring

                         6.6   Monitoring Frequency
                            .1  Characteristics of Ground-Water  Flow
                            .2  Location and Purpose  of the Monitoring Well
                            .3  Climatological Characteristics
                            .4  Trends in the Monitoring  Data
                            .5  Legal and Institutional Data Needs
                            .6  Other Considerations

                         6.7   Cost Considerations

                         6.8   Data Management
                            .1  General
                            .2  Application of Statistics
                            .3  Indicator Data Profiles
    7.                    SAMPLING, STORAGE & PRESERVATION
                         7.1   Introduction

                         7.2   Sample Collection
                            .1  Sample Collection Techniques
                            .2  Records
   - 2 -


   7. (Continued)       7.3   Sample Containers
                        7.4   Preservation of Samples  and Sample
                                  Volume Requirements

                        7.5   Preservation of Samples  in the Field
                        ANALYTICAL METHODS
                        8.1   Introduction

                        8.2   Alternate Analytical Methods
                           .1  Method Comparability
                           .2  Other Analytical Methods

                        8.3   Specific Analytical Methods of the Analysis
                                   of Relatively Concentrated Leachate Samples
                           .1  Introduction
                           .2  Measurement of Interference Effects

                        8.4   Analytical Methods

                        8.5   Brief Description of Specific Analytical
                                    Methods for Leachate Analysis
                           .1  Physical Parameters
                           .2  Organic Chemical Parameters
                           .3  Inorganic Chemical Parameters
                           .4  Biological Parameters

                        8.6   Field Testing Versus Testing in the Laboratory

                        8.7   Automated Methods

                        8.8   Laboratory Quality Control

                        8.9   Manpower and Skill Requirements

                        8.10  Records, Data Handling and Reporting
                        9.1   Introduction

                        9.2   Step 1 - Initial Site Inspection
                           .1  Nature of the Waste
                           .2  Areal Extent and Thickness of the Landfill
                           .3  Pretreatment and In-Place Treatment of Refuse
                           .4  Landfilling Procedures
                           .5  Rate of Landfilling and Refuse Age
                           .6  Liners and Covers
                           .7  Visual Survey of Topography and Geology
                           .8  Ground-Water Use (Preliminary)
   - 3 -


   9. (Continued)
9.3   Step 2 - Preliminary Investigations
   ,1  Existing Data
   .2  Preliminary Site Investigation

9.4   Step 3 - Definition of the Hydrogeologic Setting
   . 1  Surficial Geology
   .2  Bedrock Geology
   .3  Ground Water
   .4  Determine Existing Water Quality
   .5  Determination of the Rate of Leachate Generation

9.5   Step 4 - Determine the Polluting Potential of
                   the Landfill

9.6   Step 5 - Establish the Monitoring Program
   .1  Select the Monitoring Sites
   .2  Determine Monitoring Objectives
   .3  Establish the Monitoring Methods and Procedures
                   Necessary to Accomplish Objectives
   .4  Establish Management Program

9.7   Examples of Landfill Contamination Problems
   .1 Scenario 1 - A Landfill Contamination Study
   .2 Scenario 2 - A Ground-Water Contamination Study
   - 4 -

                                CHAPTER 1


The land serves as the ultimate repository for over 90% of our Nation's

solid waste.  Incineration, shredding, and resource recovery processes

reduce the amount of solid waste but produce residues requiring disposal.

The main environmental problem of concern at a land disposal site is leachate

generation and its resultant potential pollution threat to ground and surface

waters.  Leachate is liquid which has percolated through solid waste and has

extracted dissolved and suspended materials from it.  Whenever water comes

in direct contact with solid waste it becomes contaminated.  In humid areas

of the country (where precipitation exceeds evapotranspiration) there will

be a net infiltration of water into a land disposal site resulting in leachate

generation.  In arid and semi-arid areas, precipitation by itself will not

be sufficient to result in significant amounts of leachate; however, problems

can occur from deficiencies in the site, or its operation and design.  The

pollution potential of leachate along with the growing concern for the limited

assimilative abilities of our Nation's air, water and land resources all point

to the importance of monitoring

This manual is primarily concerned with the monitoring of land disposal sites

disposing of municipal solid waste (MSW).  Emphasis is placed on the monitoring

of ground-water quality, with the monitoring well being the key tool in per-

forming this function.  The manual is concerned with both existing and new

land disposal sites, the former being the more common case.

This manual is primarily  addressed  Co the bureau chiefs of tin- solid

waste regulatory agencies,  although its contents can be readily used by

operators, researchers and  consulting engineers in the field.  It is

offered as a guide  to be  used  and tailored by the bureau chief, at his

discretion, in implementing and directing an effective monitoring and

enforcement program in his  state and is intended to provide broad general

direction and guidance to persons without prior training or experience.

It will also bring  into one volume  information valuable as a reference

source for those persons  actively engaged in landfill monitoring.  It

should also prove helpful to the operators and managers of land disposal

sites who now will  find a need for  familiarization and understanding of the

fundamental principles involved in  ground-water pollution and monitoring.

This manual has a companion volume  which addresses the enforcement aspects

of monitoring.  It  is intended that, used together, the two volumes will

assist the regulatory programs to "bridge the gap" between the monitoring

performed and the enforcement  data  needs.

Generally, this manual includes fundamentals and guidelines to assist the

user in,

           . establishing the  need  for monitoring.

           . assigning priorities for sites to be monitored.

           . implementing and  directing a cost-effective, on-going

             program responsive to  the enforcement data needs.

The information, as presented, is offered as guidelines and preferred methods

only and site specificity is recognized throughout the manual.

                             CHAPTER 3

                     FUNDAMENTALS OF LEACHATE


As discussed in Chapter 2, it is  important to understand and assess the

potential for leachate contamination at a land disposal site, in order to

properly design, implement and interpret a monitoring program and its data.

Here we are referring to leachate production, its quality,  quantity and its

fate in the hydrogeologic environ.  A clear understanding of each of these

concepts, their underlying theories, causes and results, should be pre-

requisite to the design of a monitoring program.  Placement of monitoring

wells, sampling frequencies, sampling analyses, data interpretation and

environmental impact assessment will all benefit from a clear understanding

of the above-mentioned concepts.

This chapter presents an overview of the fundamentals of leachate and is

keyed into a more detailed presentation in the Appendix of  the manual.  It

is intended that the material presented will be useful to the user of the

manual in making an environmental assessment of potential leachate contamin-

ation for a particular land disposal site, and utilizing this to properly

design and operate a monitoring program and interpret the resultant data.

Further, the within information may be useful to regulatory officials in the

preparation of background and reference information for enforcement cases.

In approaching the monitoring of  a land disposal site, one  faces the following


           what kind of contamination are we monitoring for?

           how much contamination in terms of concentration and

           quantity can be expected?

           where, how fast, and how far will the contamination


           how do we best monitor for the contamination?

All of these questions require a clear understanding of leachate production

and its fate in the landfill and surrounding environment.


In understanding the quality of leachate, and contaminants and the concen-

trations that may be encountered by monitoring, one must consider its quality

as the leachate emanates from  the compacted solid waste and its quality as

the leachate travels in the subsurface environ.  The former would be the

quality of pure leachate, while the latter deals with  the quality of "leachate

enriched ground water."

Precipitation percolates into  materials deposited in a solid waste landfill

and by lixiviation  (dissolving of soluble components)  produces a solution

called leachate.  The landfill leachate under conditions where infiltration

is greater than runoff and  evapotranspiration combined, moves downward

through refuse, and through underlying soil and sediment until it reaches

an impermeable layer or ground water.  In its journey, leachate traverses

three zones of geochemical  activity with certain characteristics which are

shared and others which are unique  to each.  The ensuing discussion will

describe some  of the characteristics in each of the  zones and ways in which

they interact with  the constituents of leachate.  The  general principles


will be presented here, and a more complete discussion appears  in the



Solid waste deposited in municipal landfills is a heterogeneous mixture of

organic and inorganic materials and living organisms.  Upon deposition, and

frequently before, microbial activity begins the degradative process on

organic matter.  The microbial decomposition of organic matter  is encouraged

by moisture and warm temperatures.

Microbial activity soon uses up the supply of oxygen and causes the refuse

beyond the zone of rapid air diffusion to go anaerobic.  Anaerobic conditions

cause the end products of decomposition to be somewhat different from carbon

dioxide and water which are the products of complete oxidation.  Notable

among the products of anaerobic decomposition is methane gas.  Other organic

anaerobic decomposition products such as alcohols, aldehydes, and thiols

tend to be more odoriferous than their aerobic counterparts.  Of particular

importance with regard to leachate, are the anaerobic forms of sulfur,

nitrogen, iron, and manganese.

The percolate flows downward through the refuse which is in progressively

advanced stages of decomposition, and it passes through layers of buried

cover material.  Percolate shows a net gain in dissolved constituents  as it

progresses downward, but may lose some individual ions from cation exchange

or other reactions encountered en route.

Nitrogen present in refuse organic matter  is released in soluble  form  with

microbial decomposition.  In organic substances, nitrogen  is in  a chemically

reduced state.  With aerobic decomposition, the nitrogen is oxidized to

nitrate ion.  Under anaerobic conditions,  nitorgen  is released as ammonium

ion.  Anaerobic  conditions  are  predominant in landfills.  Thus most

nitrogen in  leachate  is  present as  ammonium.  The relatively small amount

of nitrate produced coupled with  its probable denitrification explains the

typically low nitrate concentration in  leachate.

Organic decomposition releases  carbon dioxide in large amounts under aerobic

conditions,  and  in smaller  amounts  under anaerobic conditions.  The enrich-

ment of the  interstitial gas  in refuse  by carbon dioxide results in produc-

tion of bicarbonate ion.  Bicarbonate is frequently a major anion in leachate.

Because of the reversibility  of the reaction producing bicarbonate, it acts

as a pll buffer.

Heavy metals in  landfills are primarily in their metallic state and are not

soluble.  The exception  is  with deposition of soluble heavy metal salts

either as solids or in solution.  These may come from certain industrial

activities such  as electroplating or metal pickling.  Most heavy metals

occur in solution as  cations, but a few are usually present as anions.

Anionic heavy metals  include  vanadium,  chromium, and molybdenum.

Phosphorus is released to percolating water by decomposition of organic

matter.  As  discussed below,  soils  have a high capacity for phosphate

attenuation, where as the refuse  material does not.  Phosphate can be and

frequently is produced in substantial amounts in leachate.  Were leachate

to enter ground water directly, it  would almost certainly contribute more

phosphate than percolate which  has  passed through soil and an unsaturated


Water quality parameters which  do not measure individual chemical species

include biochemical oxygen  demand (BOD), chemical oxygen demand (COD),

total organic carbon  (TOC), color,  conductance, and turbidity.  The refuse

zone provides little, if any, attenuation of these parameters, instead it

usually contributes to them.


Feral collform and fecal streptococci have been observed in leachate, and

poliovirus was reported In leachate from a simulated landfill.   The recent

trend to use of disposable diapers has increased the source of  enteric

bacteria and viruses in solid waste.  Sewage sludge and septage are also

frequently disposed of in municipal landfills.

Movement of bacteria and viruses within the landfill and through the unsat-

urated zone is dependent upon the porosity of refuse and underlying geologic

formations.  Refuse may offer many paths through which water can travel

relatively unimpeded.  If coarse sand and gravel or fractured rock under-

lie the refuse, percolating water may carry microorganisms with little or no

attentuation except for natural die off.  These conditions judging from loca-

tions which have been studied, are the exception rather than the rule.

Much data on pure leachate quality has been reported in the literature

which is worthy of note.  The U. S. Environmental Protection Agency has pre-

pared Table 3.1, which illustrates some of the chemical and biological

characteristics found in pure leachate and compares fresh leachate to a

typical domestic waste water.  The quality of leachate depends upon many

variables which are specific to each land disposal site.  Therefore, a

recent EPA report emphasizes the cautious interpretation of reported leachate


         "The compositions of leachates reported in the literature
          are. quite diverse	The breadth of reported data are
          also typical for individual studies 17 over a long period
          of time.  The many factors that contribute to the spread
          of data are time since deposition of the solid waste; the
          moisture regimen, such as total volume, distribution, in-
          tensity, and duration; solid waste characteristics; tem-
          perature; and sampling and analytical methods.  Other
          factors such as landfill geometry and interaction of
          leachate with its environment prior to sample collection
          also contribute to the spread of data.  Most of these


Chloride (Cl)
Iron (Pel
Manganese (Hn)
Zinc (Zn)
Magnesium (Hg)
Calcium (Ca)
Potassium (K)
Sodium (Ha]
Phosphate (P)
Copper (Cu)
Lead (Pb)
Cadmium (Cd)
           factors are rarely defined in the  literature, making
           interpretation and comparison with other  studies
           difficult,  if not  rather arbitrary."

 In this same report,  the EPA has  prepared  a  comprehensive summary of quality

 data for both pure leachate  and leachate enriched ground water as has been

 observed and reported by many researchers.   The  table along with some

 narrative discussion  of the  data  has been  duplicated and included in the

 Appendix of this manual.

.The significance of microbiological organisms in solid waste has been addressed

 by EPA and worthy of  note for selecting monitoring  analyses:

           "There is a dearth of information  concerning the microbiology
           of solid waste stabilization  as  it occurs in a land disposal
           site.   The  organisms responsible for stabilization are ubiqui-
           tous in nature and are  present in  the  solid waste as well as
           in the soil.   Therefore,  there is  an ever-present "seed" of
           organisms,  and microbial stabilization is inevitable.  The
           few studies available •*» 4,5,  6,7 confirm  this.  However,
           from the viewpoint of environmental contamination, the lack
           of specifity with  regard to types  and  numbers of stabilizing
           bacteria and even  pathogenic  bacteria  and viruses, is very
           disturbing  and in  need  of additional attention and/or research.
           Peterson has isolated type 3  poliovirus and ECHO 2 from muni-
           cipal  solid waste.   Other investigations  have determined
           that one gram of residential  solid waste  may contain one
           million or  more fecal coliform and fecal  streptococci  10,11.
           Soiled diapers were found to  comprise  0.2 to 2.5% by wet
           weight of the total waste stream 12 Gaby H  has shown
           comparable  density of fecal coliform and  fecal streptococci
           (Figure 1).   The preliminary  findings  indicate there is great
           public health significance associated  with any soild waste
           management  process.  Additional  work is required to clarify
           these  results and  determine the  bacteriological efficacy of
           solid  waste management  processes".


 As used herein,  the unsaturated zone is defined as the area in soil or

 sediments between the bottom of the landfill deposits  and the  water table.

 The distance can vary between zero  (refuse contacting  ground water)  to

 several hundred  feet.  The zone is below what is usually considered "topsoil"

             Mote:  1.  Average of 6 to 8 Determinations
                    2.  Adapted from W. L. Gaby, U.S. EPA Research Contract
                        68-03-0128, 1972.
         3.   W/QL  Total Coliform

         A.   ]   1  Fecal Collforn

         5.   &XX1  Fecal Streptococci
                 SOLID WASTE
                        SEWAGE SLUDGE

or the weathered, organic-matter-rich upper horizons of most soils.   At most

landfill sites, topsoil has been removed, and sometimes much subsoil also,

prior to deposition of refuse.  The porous materials comprising the subsoil

are likely to be low in organic matter, have a sparse microbial population,

and may vary in permeability over a wide range.  For purposes of discussion,

we will consider the unsaturated zone to be 20 to 200 feet thick.  This

range allows percolating water an opportunity to react chemically with its

environment before reaching ground water.  Percolating water has four options

in passing through the unsaturated zone.  It can move virtually unchanged,

can show a net gain of solute, show a net loss of solute, or keep the same

total ionic concentration with a net exchange of ions.  Since few soils or

sediments are chemically inert, changes in transported solute are to be


Chemical activity in the unsaturated zone is primarily located at the surfaces

of clay minerals and hydrous oxide coatings.  Limited microbial activity may

take place either from the indigenous population or  that transported from


Cations will be  removed from solution until either  the cation exchange

capacity is reached, or the limit of displacement reactions  is reached.

The limit of cation exchange capacity  (CEC) can range  from nearly zero

to probably not  more than  60 milliequivalents  per 100  grams  of soil.   Sol-

ution concentrations, pH,  and  percolation rate affect  the reactions quan-

titatively.  It should be noted that absorption is not  a  permanent  fixation.

Cations may be  described with  changes  in solution composition, pH,  or

oxidation-reduction  (redox) potential.

 Divalent  and trivalent cations include most of the heavy metals.  These

 are  held  more strongly than sodium,  potassium, or  ammonium on  the cation

 exchange  complex.   Di- and trivalent cations will  displace monovalent

 cations which are  adsorbed.

 Heavy metals are prone to sorption on hydrous oxide coatings in the soil.

 The  hydrous  oxides are frequently cited as so limiting metal solubility that

 agricultural deficiencies of copper, zinc, and cobalt occur.      Atten-

 uation of heavy metals present in leachate is desirable.   In locations vir-

 tually free  of clay minerals, these  coatings may be present on sand grains

 giving  - the sandy formation some  ability to attenuate metallic ions.

 Absorption is only one mechanism for removing dissolved ions from solution.

 Changes in the geochemical environment can also affect solution equilibria.

 A transition from  reducing conditions in the landfill to oxidizing condi-

 tions in  the unsaturated zone can reduce the concentration of  some redox-

 sensitive species   in solution and change the chemical form of others.  Iron

 and manganese will oxidize and precipitate from solution,  for  example.

 If porosity  will allow bacterial movement, biochemical reactions involving

 leachate  constituents can proceed.  Sulfide and ammonium can be oxidized to

 sulfate and  nitrate.   Dissolved organic matter measured in terms of BOD and

COD can be reduced through microbial decomposition.  Some  nutrient elements

in the course of these reactions will be incorporated in bacterial ce£2s

and thereby  be  removed from solution until the bacterial cells die off.

Conversion of  ammonium to nitrate changes nitrogen from a  form subject to

attenuation  to  a form which is not.   Sulfide to sulfate oxidation is not ex-

pected to be as  significant.   Sulfide can form insoluble precipitates with

many of the heavy metals.  For this reason, it may not be present in more

than trace amounts in leachate.  Microorganisms may also attack the organic

ligands associated with chelated and complexed metals.  Decomposition or

absorption by microorganisms would remove the metals from leachate.

Phosphate reacts with a variety of soil components forming insoluble

products.  Calcium and phosphate react in solution to form hydroxyapatite,

the least soluble phosphate compound known.  Iron, aluminum, and manganese

can also form virtually insoluble precipitates with phosphate.  These reac-

tions lead to a strong attenuation of phosphate when these metal ions are

present in the unsaturated-zone.

Carbonate also reacts with calcium, magnesium, and some heavy metals forming

relatively insoluble compounds.  Calcareous deposits in the unsaturated zone

can be valuable in attenuating phosphate and heavy metals from leachate.

Because carbonate neutralizes acids, BOD and COD as expressed in organic acid

concentration may also be reduced.  Carbonate induced alkalinity may change

solubilities of heavy metal chelates and lead to a deposition of heavy


The unsaturated zone is influenced by the percolation of leachate into it

and influences the leachate which percolates into it.  Water of low oxida-

tion potential first infiltrating into the unsaturated zone of high oxida-

tion potential will become more oxidized while simultaneously reducing sub-

stances in the unsaturated zone.  A continued percolation of reduced water

may convert what had been an oxidized system into a reduced one.  Or, the

percolate may become oxidized if that capacity  Ln the unsaturated zone is

greater.  The degree of influence of reduced leachate on the oxidized unsatur-

ated zone and vice versa  depends upon the reserves of material capable

of oxidizing or reducing  in  the unsaturated zone and leachate.  The greater

the distance leachate  travels between refuse and ground water, the better

the chance  that the entire path through  the unsaturated zone will not be-

come reduced.  Raising the oxidation potential of leachate will tend to

attenuate some components in solution at the point of exit of the refuse



Concepts useful for describing surface water pollution are generally not

valid for ground water.   Ground-water movement is described by Darcy's Law

which states that velocity is directly proportional to the permeability

of the aquifer and the hydraulic gradient, and inversely proportional to the

porosity.   Ground-water flow velocities  vary over a wide range with 5 ft/yr

to 5 ft/day being a typical  range.  Highly permeable outwash glacial

deposits, fractured basalts  and granites, and cavernous limestone aquifers

allow very  much higher velocities.

The generally slow velocity  of ground water allows laminar flow which ex-

hibits different characteristics of mixing than does turbulent flow usually

associated  with surface streams.  A water of different chemical composition

from ground water which is injected or percolated into ground water tends

to maintain its Integrity, and is not diluted with the entire body of ground

water.  Instead, it moves with the ground-water flow as a plume undergoing

minimal mixing.

The plume shape is determined by the physical characteristics of the aquifer.

Porous media give somewhat different shaped plumes from fractured rock or

cavernous limestone.  Chapter 4 illustrates the paths of ground-water

movement In various hydrologic regimes.

Differential attenuation is defined as a reduction in concentration of a

dissolved constituent, with distance along the direction of water flow, which

is disproportional to changes in concentration of other constituents. Differ-

ential attenuation may result from chemical reactions which remove the con-

stituent from solution or from self-destruction.  Apparent attenuation

occurs from dilution by mixing with water of lower constituent concentration.

Dilution may take place in ground water in two ways.  One is hydrodynamic

dispersion, and the other is molecular diffusion.  Microscopic dispersion

describes mixing caused by the tortuous flow of water around individual

grains and through pores of various sizes in a porous aquifer.  Microscopic

dispersion describes mixing as water flows in and around heterogeneous

geologic formations.  Molecular diffusion operates on a much more restricted

scale.  It is the diffusion of solute across a concentration gradient from

stronger to weaker concentration.  Diffusion is seldom possible  to measure

in the field.  There are mathematical formulas which describe dispersion.

By measuring enough physical and chemical parameters at a site,  over a suf-

ficient length of time, one can calculate an approximate value for dispersion.

Chemical interactions provide  the greatest amount of differential attenuation

in the aquifer zone.  Hydrous  oxides of iron, aluminum, and manganese, or

clay minerals present in aquifers attenuate cations  in  the same  way  that they

do in soils or in the unsaturated zone.  Because  hydrous oxide and clay

colloids are in constant contact with water in  the aquifer, it can be  assumed

that the exchange sites  are  saturated and essentially in equilibrium with

the ambient ground water.  Leachate enriched ground water when contacting

these colloids will  initiate cation exchange which results in desorption of

cations which are less strongly held than those replacing them.  In this way,

hydrogen, sodium, calcium, and magnesium may be released into the aqueous

phase by exchange with heavy metals and other cations in leachate.  High

hardness values associated with leachate plumes may be due in part to this

ion exchange phenomenon.

Chemical precipitation in  the aquifer is possible if the natural ground water

composition includes ions which form insoluble compounds with constituents

in leachate.  An example would be  formation of hydroxyapatite with leachate

phosphate and calcium in ground water.  Changes in redox potential, buffering

reactions, or changes in lithology may produce other attenuation reactions.

The third means of attenuation in  aquifers is that termed decay.  Oxidation

of organic compounds produces carbon dioxide and water, and eliminates

the compounds.  Radioactive  species undergo radioactive decay to stable

daughter products, but radioactivity should not be significant in leachate

from municipal landfills.  Microorganisms carried into the aquifer zone are

deprived of a good nutrient  supply and are subjected to a generally cooler

temperature.  This results in a lowering of biochemical activity, frequently

to the point of cessation.   The inactivation coupled with natural die off

tends to reduce bacterial numbers  rather rapidly.

There are two additional complications in the interpretation of ground-water

quality in leachate  plumes.   One is the variation in leachate concentration

with time, and the other is  the discontinuous recharge of leachate which

occurs in most geographical regions.  Chapter 6 presents additional

discussion on data interpretation.

Leachate production begins as soon as deposited refuse is wetted to field

capacity.  The lag time depends upon local climatic conditions and rate of

refuse deposition.  In an active landfill, older organic matter is stabilizing

while simultaneously new organic matter is beginning to ferment and produce

stronger leachate.  The net effect is an increasing leachate concentration

from a given area, or an increasing areal contamination, or both as long

as the landfill is active.

Leachate produced at the initiation of percolation through the landfill is

less concentrated than that produced after several years' refuse accumulation.

This leachate will be found at the distal end of the plume of leachate-con-

taminated ground water.  The closer the sampling site to the landfill, the

more concentrated should be the contaminated ground water.  An increasingly

concentrated leachate source in addition to the factors of dilution and

attenuation must be considered in interpreting the results of sampling the

plume.  An erroneously high value for attenuation or dilution may be given

if the variation in source strength is ignored.

The intermittent recharge occurring from most landfills also complicates

interpretation of leachate-plume configuration.  During summer months when

evaporation frequently exceeds rainfall, little or no leachate may be pro-

duced.  Ground water, however, moves under the landfill at a relatively

steady rate.  Thus, there will be variations in the volume and strength

of'leachate reaching ground water during the course of time.  These variations

will show in the leachate  plume as variations in total solute concentration.

A sample taken from the plume at any given time may represent a "high" or

"low" in the intermittent  recharge pattern.  Oneway to visualize this

phenomenon would be to watch the response of a conductivity probe in a well

screen over time.  As leachate-enriched ground water moves past the point,

conductivity will vary with changes in dissolved solids concentration.

The variations may be noticeable only in time spans of weeks to months.

Again, this complicates efforts to calculate values for dispersivity or

dilution because concentrations vary from factors other than aquifer char-


A generalized summary of the susceptibility of leachate constituents is

provided in Table 3.2.  The mechanism of attenuation which affects each

constituent is listed for  the zones through which leachate may pass.  When

data are summarized in this fashion, only the principal mechanisms can be

cited.  For example, no attenuation is listed for all of the constituents

in the refuse zone.  This  is not really true as the previous discussion

points out.  However, quantification is impossible, and there is a net output

of most of the constituents.  Sulfate, nitrate, and ammonium are given bio-

chemical conversion alternatives.  These ions are subject to oxidation and

reduction reactions which  may convert or eliminate them.  Heavy metals are

also prone to one or more  of the attenuation mechanisms, and may not be

universally present in leachate.  Biochemical reactions were not listed for

the aquifer zone because biological activity is inhibited.  In places,

biological activity may be significant in the aquifer, but  the amount and

type cannot be predicted.

Attenuated Constituent
Heavy metal onions
Heavy metal cations
(Pb, Cu, Ni , Zn, Cd, Fe, Mn, Hg)
Organic nitrogen
Volatile Acids
Refuse Zone


Unsaturated Zone




0 = no attenuation
A = adsorption
B = biochemical degradation on conversion
C = chemical precipitation

Measurement of Attenuation

From the previous discussion, it is evident that attenuation describes two

phenomena associated with the way solute is transported.   One is  dilution

which results from dispersion and diffusion, and the other is dilution

resulting from chemical or biochemical removal of solute from ground water.

The former type of dilution is referred to as apparent attenuation because

no active chemical processes are operating to reduce the concentration of

dissolved constituents.

In the field, it is important to distinguish between apparent 'and active

attenuation because prediction of future conditions depend upon the extent

of active attenuation.  To accomplish this, several samples of leachate-

enriched ground water must be collected along the path of travel  of the

leachate plume.  Chemical constituents measured in these samples  are then

chosen on the basis of their susceptibility to attenuation, and relative

changes in concentration with distance from. the source are noted.

Chloride is the best constituent to measure as a indicator of dilution.

Because it carries a negative charge and does not form precipitates with

the common cations in water, chloride is unaffected by ambient conditions.

Reductions in chloride concentration can then be attributed to the result

of dispersion and diffusion.  If ground-water equations were used in an

attempt to calculate dispersion coefficients for leachate-enriched ground

water, chloride concentration data would be first choice for use in  the

calculations.  Nitrate reacts in virtually the same way, but nitrate is less

frequently present in leachate in comparable concentrations.
                              3-/7 A,

                                                                   r  I
Concentrations of other constituents sampled simultaneously with chloride
should represent equal dilution.  If they are observed  in lower than  ex-
pected concentrations , this indicates that active attenuation has ^OHQBI  f*-**
^StaB**  Conversely, if their concentrations are greater than those  calculated
on the basis of chloride, desorption from ion exchange  sites or contribu-
tions from other sources may account for the non theoretical results.
An exasiple which is calculated from data obtained in a landfill study is
  c             \\
presented below. *'  The cations calcium, sodium plus potassium, ammonium,
and iron in leachate-enriched ground water are plotted in percentage of
original concentration vs. distance from the landfill (Figure 3- I ).  Were
all of the cations diluted equally, they would plot on the same curve.
Reference points for chloride are included to facilitate a comparison of
the theoretical dilution-only curve with the actual cation concentration
The plume of leachate-enriched ground water represented by Figure 3- |  is
produced by a landfill that has been active for 28 years.  The leachate
plume can be traced about 10,600 ft. downgradient from the landfill.  The
plume extends vertically throughout the thickness of the aquifer (about 80
ft) with the most concentrated contamination near the bottom.

Calcium remains above the chloride curve throughout the length of the plume.
This is in agreement with other reports which have indicated that calcium
is desorbed from clays as a result of cation exchange with leachate
components.      In this specific situation, there may also be a contribution
of calcium from septic tank effluent.

Ammonium remains above the chloride curve for about half the length of the


plume.  It  also may be desorbed and is also a eooponent of septic  tank

effluent.   The loss of ammonium at more distant points of the plume may be

due in part to generally more aerobic ground-water conditions that allow

nitrification of ammonium.

Sodium and  potassium  generally plot below the chloride points, and iron

is even more attenuated.  Probably the iron is removed largely through

solubility  changes resulting from increases in Eh at longer distances

from the landfill.

The geohydrologic environment is  characterized by soft, rather acid native

ground water in a highly silicaceous unconsolidated sand and gravel  aqui-

fer.  Dncontaminated  ground water contains iron in concentrations which

frequently  exceed the recommended drinking water limit of 0.05 mg/1.  No

significant amounts of clay or  silt are present in the path of the

leachate plume.  Sand grains  are  coated with iron oxide which probably

exhibits a  small amount of cation exchange capacity.  Septic tanks in use

in the  area and intermittent  recharge of leachate as governed by climate

complicate  the interpretation of  chemical data along purely theoretical


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In a recent EPA report on leachate  ^ , leachate production was phased

into perspective.  It stated:

         "It becomes quite evident  that the main parameter affecting
         leachate quality and quantity is purely and simply the quantity
         of water flowing through the solid wastes.  Generally, the more
         water that flows through the solid waste, the more pollutants
         will be leached out.  Therefore, the proper sanitary landfill
         design and operational approach is to eliminate or minimize
         percolation through the solid waste.  With the smaller amounts
         of percolation, the pollutants tend to-be more concentrated,
         but the rate at which they are transmitted to the surrounding
         environment is not so apt  to exceed the capability of the
         natural surroundings to accept and attenuate most of them to
         some degree."

Therefore, you can see that the volume of leachate generated is influenced in

both the extent of a leachate contamination problem and the relative strength

of the leachate and           its concentration in the ground water being


The water balance method has been presented as a useful tool in estimating

average leachate quantities at a land disposal site.

         "The sanitary landfill site  is a part of  the classical
         hydrologic cycle.  The governing criteria for determining
         leachate volume are  those  describing  the  phenomena occurring
         at  the cover material surface.  A water balance can be written:
                  WR+  WSR+  WGW+  WIR
         where  WR =  input water from precipitation

                WSR = input water from surrounding surface  runoff

                WGW = input water from groundwater

                W,R = input water from irrigation

                  I = Infiltration

                  R = Surface Runoff

                  E = Evapotranspiratio'n


         Infiltration can be defined:

                       I =ASs = ASR +  L  * WD	(2)

         where ASg »  change in moisture storage in soil

               £SR =  change in moisture storage in solid waste

                L  =  leachate

               WD  =  water contributed by solid waste decomposition

         Proper design and operation can eliminate input water from
         surrounding surface runoff, groundwater and irrigation.  Some
         control can be exerted over infiltration, evaporation, surfa'ce
         runoff, and moisture storage capacity of soils and solid waste.
         The volume of water produced during solid waste decomposition
         is generally considered negligible."  (4)

Figure 3-1 conceptually depicts the above water balance equations.  In addi-

tion, the above-referenced report presents very useful information and data

on the following:

         1.   the influence of slope, surface condition, and soil

              type on the quantity of runoff and the potential for

              leachate production.

         2*   the  dependency of infiltration on the storm frequency,

              duration, intensity and soil moisture conditions.

         3.   the influence of vegetation on evapotranspiration and


         4.   the relationship of soil permeabilities to infiltration

              rates and volumes.

         5.   the moisture retention capabilities of various types of

              soils as well as compacted municipal solid waste.

All of the above-referenced information provides useful input in assessing

leachate at a land disposal site.  For the convenience of the users of this

manual, sections of  the  EPA summary report on leachate feu/2.been reproduced

and included in the  Appendix.
In another EPA report,      the water balance method was applied to three

hypothetical landfills.   These examples are worthy of note and have been

included in the Appendix  of this manual.  They demonstrate how to determine

time of first appearance  of leachate as well as subsequent average leachate

generation and volumes.

Caution must be exercised in applying  the water balance method to sanitary

landfills.  Review of the above-referenced information clearly shows the

extreme sensitivity , of leachate quantity estimates to the many variables

used in the water balance calculations .  For example, slight changes in

runoff coefficients, evapotranspixation or moisture retention figures can

result in a significant change in  the  leachate quantity estimate.  In

addition, unless extensive on site measurements- are performed, the many

parameters in the water balance calculations are purely theoretical and

empirical estimates.  Therefore, this  manual presents the water balance

methods as a useful tool  for planning, design and assessment purposes and

the leachate quantity estimates generated should be viewed with this quali-

fication in mind.

                                       PRECIPITATION (WR)
                               FIGURE 3-1

    In the context of this - report the ultimate goal of any monitoring

    program is to gauge and evaluate ground-water degradation^, if any,

    duo te landfill leachate.  A presence/absence system is the

    minimum acceptable approach - is there leachate in the ground water?

    This approach will work in situations where ground-water contamination

    did not pre-exist the'monitoring network, in other words, a network

    installed prior to any landfilling operation.  As is often the case,

    landfill operation and subsequent leachate generation have been

    going on for some time prior to installation of a monitoring network.

    If contamination already exists, the monitoring program must provide

    the requisite data for the management program.  Here,the maximum

    feasible approach is- a quantitative evaluation of total contaminant

    accumulation in the aquifer, rates of accumulation and attenuation,

    and the contaminant dispersion pattern and its controls.  To implement

    this approach, a time sequence of three-dimensional data on the

    contaminant body is required;actd with this information, the proper

    management scheme can be devised.  For any given sanitary landfill,

    the correct monitoring system will be between or even include, these


    There are two basic approaches to monitoring: active and passive.  The

    former has a measurable, continuing impact on the ground-water regime,

    considerable altering the flow system in which the contaminant source

    is located.  An active monitoring system is essentially a pumping welj.

    which intercepts ground-water from the area that might potentially  be

    affected by the contaminant  (Figure 1 ).   Theoretically, any

contaminant entering the zone of intercepted ground-water flow

would eventually be detectable in the monitoring well discharge.

This approach is most suited for point source,  "one-shot"

contaminants introduced into the ground water from such sources

as a tank leak or underground nuclear explosion.   Unfortunately/

this type of monitoring scheme has several drawbacks preventing

its application to sanitary landfills: 1)  the larger the

contaminant source, the greater the number of pumping wells

required to intercept ground-water flow; 2} contaminant

concentrations will be greatly reduced by the volume of water

withdrawn, perhaps below detection limits; 3) disposal of the

pumped water can be a problem, especially if contaminated; 4)

pumping costs over a period of years will be astronomical; and

5) pumping will accelerate the spread of leachate through the

aquifer and eventually the monitoring system will become a

pumped withdrawal system.

Passive.monitoring, on the other hand, is ideally suited to

monitoring landfill leachate.  In this type of scheme, wells or

other monitoring devices, strategically located in reference to

ground-water flow directions, are sampled at regular intervals

to determine chemical constituents in the ground water at that

point and time.  Flow-pattern disruptions are kept to a minimum.

This is a system that can be used to monitor continuous, long-

term contaminant input from a point source - the situation that

would exist at a landfill.  To monitor the area which might be

affected by the contaminant, a "picket fence" of non-pumping wells

is required  (Figure 2 ).  The main drawback, compared to the

active monitoring approach,  is  that more  than one weTLl is

required.   However/  these can be small-diameter wells and

sampling procedure costs can be kept to a minimum and should

cost  less  in  the  long run than  a major pumping installation.

Background Data Requisite for Monitoring  Network Design

Prior to monitoring  well construction,  some thought should

be given to their placement.  A certain amount of information

is required:  1) ground-water flow direction; 2) distribution

of permeable  and  impermeable materials; 3) type of aquifer

porosity;  4)  effect  of pumping, present or future, on the flow
system; and 5}  background water quality.  ThAo data can be

obtained by installing a series of low cost wells, collecting

sediment samples  during drilling,  and measuring water levels in

the completed wells.   Background water quality can be determined

from  chemical analysis of water samples from these wells.  A

hydrogeologist  or engineer familiar with  ground water, may be

able  to "best guess"  the information without actual field work.

However, unless such personnel  are involved in designing the

monitoring network,  every effort should be made to collect this

information at  the site.   With  this information, monitoring wells
can be placed to  most effectively intercept any contaminant bulb

spreading  from  the landfill.

Monitoring Networks  for Sanitary Landfills

The minimum acceptable monitoring well network will consist

of one line of  three "picket fence" wells downgradient of the

                                       DP A ET
                                       !K f\ ,'i   i
landfill and perpendicu^/r to ground-water flow,  penetrating

the entire saturated thickness of the aquifer;  one well within

the confines of the landfill, screened so that  it intercepts

the water table; and a well completed in an area upgradient

from the landfill that will not. be affected by  potential

leachate migration.  The actual number of wells will be dictated

by the size of the landfill, the hydrogeologic  environment, and

budgetary restrictions, but there should be a minimum of five

at each landfill and ideally one "picket fence" well for every

250 feet of landfill frontage perpendicular^flow direction.

Even'if wells are sited according to the background information

described above, there is a high probability of one or more of them

not intercepting the ba-lb of leachate-enriched  ground water

because of inhomogen^Lties in aquifer material^  efee.  Sequence of

land-filling operations also has a significant  effect on the shape

of the leachate plume and the possibility of a  well not detecting

leachate, (Figure 3 ).  For these reasons, it is better to err on

the side of too many monitoring wells rather than too few.

Once contamination is detected, several "picket fence" lines of

these wells can be constructed and used to gauge downgradient

dispersion and attenuation of the leachate, providing the

i|f^)brmation necessary for predicting the ultimate fate of the plume.

If, however, the contaminant exists in a complicated hydrogeologic

regime, information on its vertical distribution is required to

predict plume behavior and assess its impact.  This is the maximum

feasible approach and will be a time consuming  and expensive

process, the necessity of'which will depend on t; 3 gravity

of the threatened environmental impact or regulatory requirements.

The single well in  the  landfill, provided it is properly constructed,

will give an indication of whether or not leachate is reaching

the ground water before it is detected in the downjgradient

"picket-fence" monitor  wells.  Once detected here, it may be

only a matter of time before leachate-enriched ground water

reaches the downgradient monitor wells.  For this reason, it

serves as an important  early warning system of potential large-

scale aquifer degradation.  Detection of leachate in this well

should trigger a response from the landfill operator, either

implementation of remedial action or wait and see what the

"picket fence" wells show.  The actu^al course of action is

dependent on federal, state, and local statutes and enforcement

agencies governing  ground water contamination or an evaluation

by the operator  ( or operator's consultant ) of the consequences

of aquifer degradation.

Some problems can result from relying entirely on this well

or similar wells within the landfill to monitor leachate infiltration

to the ground water.  First, it is located within the landfill

proper and does not provide information on the downgradient

extent of leachate-contaminated ground water.  Then too, it skims

water from only the surface of the aquifer.  If any density

stratification is occuring within the contaminant bulb, the well

would give an unrealistic picture of actual leachate concentration

in the ground water.

                              KAh  8
The major problem, however, is the potential for artificially

elevated leachate concentrations in water samples due to improper

monitor well construction.   Since the well is constructed within

the landfill itself, an improperly backfilled annulus can act

as a conduit for downward movement of leachate, introducing it

into the aquifer sooner than might have occurred naturally, if

at all.  Proper construction requires some type of impermeable

seal in the annular space between the well casing and the

borehole wall, either bentonite or neat cement grout.  Because

grout can shrink and bentonite can dry and crack, their placement

is not a complete guarantee of plugging the annular area and

stopping downward movement of leachate.  However, neglecting to

place this seal during monitor well construction is almost certain

to speed and promote ground water contamination.

An upgradient monitor well provides water samples indicative

of background water quality, or in other words, the chemical

character of "naturally" occuring ground water.  This well

should be sampled at regular intervals, and the analytical

results used as a baseline for comparison with results  from the

landfill and "picket fence" monitor wells.  The background well

can also provide  information on outside interferences,  that is

contaminants in the ground water, naturally occuring or otherwise,

not due to landfill leachate.  When a  constituents concentration

rises  above acceptable  levels in  all the wells, an outside
                                  if  / '
                                  , - ./ -

 interference is indicated,  A^aturalJLy-occuring) example of this

 is^lron-rich ground water and X aVtifiViallV-Induce^ examples -oaRHoe-^^pleiwen±ed~^fc-an.y^j^te^wii;h.^M fy pgobatoillt'y
o-f--inte*ceptin^--fehe~€0rvtaininan-t--b**ibn  Hydrogeologic  conditions

at  a  particular site will require modification  of  the basic design
                                                                     . ')

Table 1'.- Typical Intergronular Porosities
	Material	per cent

Clay                                     45-55
Silt                                      40-50
Medium to coarse mixed sand              35 - 40
Uniform sand                             30 - 40
Fi«ve to medium mixed sand                30 - 35
Grivel                                  30-40
Gravel and sand                          20 - 35
Sandstone                                10-20
                                                       8 •
                                     »   '

in order for the monitoring network to be effective.  These

basic designs are presented Here as guidelines, not standards,

because they are the minimum feasible approach to monitoring

and by nox means will provide all the answers in all of the

various hydrogeologic environments found in the United States.

As a result of past structural deformation, consolidated

sediments and igneous and metamorphic rocks are fractured (broken)
to a greater of lesser degree depending on the itensity and/or

frequency of the deformation and the rock type.  Water can, fill
          v   -  • -
these fractures, and if they are interconnected and capable of

transmitting water, can form an aquifer. (Figure 4f).  The

ability of the aquifer to transmit wa,ter depends on fracture

density and openness: the greater the density of fractures and

the wider they are, the greater their ability to transmit water.

In some cases, the rocks can have, primary and secondary porosity;

primary porosity (intergranular porosity) is produced during

sediment deposition or rock formation and secondary porosity is

caused by fracturing or solution activity after this.  Sandstone

is an example of both types of porosity since voids exist between

the sand grains and•sandstone formations are usually fractured.

However, intergranular porosity dominates unless the voids are

filled with cement.

Carbonate rocks are susceptible to solution by water moving through

fractures.  With time, these fractures are enlarged into cavities,

creating large open spaces in the rock.  Figure 4e).  If the

cavities are connected, ground water can move very rapidly through

the aquifer.  In fact, carbonate aquifers can have transmissivities

of several million gpd/ft.  Solution openings and sinkholes provide

open pathways  for  leachate  to reach the ground water, and

once there, it will  move  rapidly through the aquifer.

Carbonate rocks  can  have  both intergranular and fracture

porosity/ but  where  solution cavities exist, ground water will

preferentially move  through them.

Type I Network (Intergranular Porosity Aquifers)

Placement, both  areal  and vertical, of monitor wells in any

hydrogeologic  environment should be. done in reference to

ground water flow  paths.  Rather than discuss this at length

simplified diagrams  are used to represent typical flow

patterns in the  type of aquifer discussed  and the positioning

of monitor wells to  effectively intercept any contaminant ^lu^e.

itttib.  Figure  5  A  and  5 B represent vertical and areal flow

distribution respectively,  in a homogeneous, isotropic

sand aquifer.  Monitor wells A, B, and C are the background,

landfill, and  "picket  fence" wells discussed above.  To

review, Well A provides baseline water quality data, Well B

is an early warning  system  showing leachate reaching the

water table immediately beneath the landfill and Well C is

intended to intercept  any plume of leachate contamin,ed ground


Areal placement  of the upgradient, background monitor well

(Well A) is critical if there is a ground water mound associated

with the landfill.   This  mound, produced by increased infiltration

due to landfilling,  causes  a certain amount of upgradient flow

from the landfill  (Figure 4B).  If Well A is located in this

zone, sampling will produce an anomalous water-quality baseline.
Unfortunately, no rules of thumb can be given as to the
separation between this well and the landfill proper as the
extent of upgradient flow will depend on a variety of factors
including amount of infiltration through the landfill and
aquifer characteristics.  The best policy would be to locate
the well at the most distant upgradient point at the landfill
site or on adjacent upgradient property if permission of the
owner can be obtained.  Well depth is not critical, assuming
there are no apparent contamination sources in the vicinity,
but better baseline data would be provided if the well were
screened through the saturated thickness of the aquifer.

Well B can be located anywhere in the landfill but
preferentially in the first section to be filled.  As discussed
above, great care must be taken during construction.  In hydro-
geologic environments where the water table is 5 to 10 feet below
the  landfill, monitoring the zone of aeration is probably not
necessary because Well B will detect leachate entering the
ground water.  However, where the unsaturated zone is 10 feet
or greater in thickness, some monitoring device is required
to detect to downward percolation of leachate before  it reaches
the  water table.  Pressure-vacuum lysimeters can be used to
trace downward movement of  leachate in the vadose  zone and can
provide data on the amount  of attenuation and the  likelihood of
leachate reaching the water table.
The  "picket fence" wells  (C wells.  Figure 5B) should  be

immediately downgradient of  the  landfill in order to intercept

the leachate plume as soon as  possible.  Once leachate enters

the ground water,  it is difficult  to control and the sooner  it

is detected, the easier it is  to evaluate its impact and initiate
remedial action, if necessary.   Well C is shown• screes! through

the entire saturated thickness of  the aquifer.  This is

recommended because the actual flow path of the leachate plume

is not known unless previously defined by head relations in  a

large number of observation  wells.  The flow .path of leachate-

enriched ground water shown  in Figure. 4A is characteristic if

the landfill is located in the aquifer recharge area.  If the

landfill were closer to the  point  of discharge, in this case

the river, the plume would probably be higher in the aquifer.

However, since the physical  behavior of contaminant bodies hasn't

been completely described yet, there is almost no way of

knowing where the bs*b of contaminant will be within an aquifer.

Therefore, the monitoring device has to collect water over the

entire saturated thickness of the  aquifer and the simplest way

to do this is to screen the  entire interval.

This typ^ of construction can cause  some problems.  The primary

problem is that the well can contribute to the vertical spread

of contaminant by providing a conduit  for downward movement of

intercepted ground water.  If the  aquifer is  50  feet or less in

thickness, this is not a major problem because natural  flow

conditions would tend to uniformly distribute  the  leachate

throughout the aquifer, especially in  recharge areas.  Thicker

aquifers, 100 to 200 feet of saturated thickness,  tend to

have more pronounced shallow and deep flow systems and

there is a chance the Leachate plume would remain the

shallow flow system.  A well screened over the entire

saturated thickness provides a movement path from the

shallow to deep flow systems.  Of course, this is a gross

simplification and is intended as a guideline only.  The

actual flow pattern will depend on the hydrogeologic

environment in which the landfill is located.

This drawback can be overcome by using a well cluster

(see Section	) but the landfill investigator will have

to balance the extra cost against the probability of promoting

the vertical spread of contaminants.  Also, well clusters

are not particularly effective in aquifers thicker than one

hundred feet.  Because the exact vertical location of the

plume is not known, overlapping or sequential  (0 to  10 ft, 10

to 20 ft, and so on) screens are required.  For example, in

an aquifer with one hundred  feet of saturated  sediment, five

wells with twenty feet long  screens are  required to  cover

this interval.  As aquifer thickness increases, screen lengths

must increase proportionally and the information on  the

vertical distribution of contaminant becomes  less  and less
precise.  If the screens do  not overlap,  the  contaminant ±M±±b •

could pass between  the screened intervals and remain undetected.

Another problem  is  dilution  of  leachate  below analytical

detection limits when a  sample  is pumped from the  well.  This

would result  in  a  time  lag  between  first arrival of leachate-

enriched ground  water at  the monitor well and its first detection

in the sampled water.   The  magnitude of this lag is hard to

predict but,  as  the  contaminant  travels in a defineable -btribb. <->•*£.

with a' small  zone  of diffusion to uncontaminated water, it

shouldn't take very  long  for the zone of diffusion to move past

the well and  leachate contaminated  ground water start to enter.

Then, if detection is still a problem, concentration or extraction

techniques could be  used  for key leachate tracers to determine

their presence or  absence in the sample.  Once detected, a more

sophisticated sampling  device is required, perhaps well clusters,

sampling during  drilling, or others discussed below, since C

wells are only designed to  show  presence or absence of leachate

and not vertical distribution.

Type II Monitoring Network  (Fracture Porosity Aquifers) -

Ground water  flow  patterns  are not  as predictable in fractured

rock aquifers as they are in aquifers with intergranular porosity.

Unless there  is  primary porosity, as in a sandstone aquifer,  ground

water flow patterns  will  be controlled by the fracture pattern.

Again, flow patterns are  presented  visually in Figures 6A and 6B,

rather than attempting  to describe  them in great detail.  The same

configuration of A,  B,  and  C monitor wells can be used in this

hydrogeologic regime (Figure  6A).   However, the wells are not

screened but  rather  are open hole with the exception of casing-off

                                               "~a iu"

                                               I"  I

surficial materials to prevent them from caving into the open


A major problem in fractured rock terrains is intercepting

the fractures that might contain leachate-contaminated ground

water with a monitor well.  As shown in Figure 6C, a well can

fail to intercept any fractures and will be dry, necessitating

another well nearby.  Worse yet, a monitor well could intercept

a set of fractures not connected to the landfill and fail

entirely to show leachate entrained in the ground water.

Without intensive and expensive geologic analysis,  it is not

possible to predict flow paths other than general ground water

flow direction at the site.  Monitor wells cannot be precisely

taken into account in planning a monitoring network  and

evaluating the results.  To compensate, a high well  density is

required, perhaps one monitor well for every 100 feet of landfill

frontage perpendicular to ground water flow.

Another problem is specifying well depth.  Fractures are squeezed

shut with depth because of the weight of overlying material.  If

shut, fractures are unable to act as conduits  for water movement

and the rock can no longer be considered an aquifer.  Closed

fractures therefore provide a downward limit on leachate

movement.  A general rule of thumb is that fractures tend to

close at depths of 300 feet or greater, and monitor wells probably

should not be drilled deeper unless there is geologic

information to the contrary.

Type  III  Monitoring Network '(Solution Porosity Aquifer) -

Similar to  fractured rock aquifers,  ground water  flow patterns

are 'going to be controlled by solution openings or fractures in

carbonate rock aquifers.   The positioning of  the  A, B, and C

monitor wells in this type of flow system is  shown in Figures

7A and 7B.   The monitoring network is the same as that for

fractured rock with the same problems:  1) intercepting the

solution  cavities and 2)  well completion  depth.   Again,

increased well density can solve  the former but there are no

handy rules  of thumb for the latter,  as in fractured rocks.

Sinkholes can be 100 feet or more deep and there  is no telling

how deep  solution cavities will persist.  Unless  the solution

cavities  follow a well known regional fracture system, there is

no way to predict their position  prior to placing a monitor well

without geologic analysis.   A trial  and error approach to

placement is  mandated by  the hydrogeologic environment and there

is no assurance that the  wells will  intercept the contaminant baib'

                                    Single pumpin

                                         nonpvLmptng wells

/      __ '  -- ' ---'-   I—^	—^J——

               r«N A ff=a cm*
\? /

•W fa

                      / /7Y7///





V  >v;.  ?  /.

                     r o

       xW. V®
                                                   to o..


 The rate, direction and distance of leachate travel from a landfill to an ultimate discharge

 point will be largely determined by the hydrogeologlc setting. The  leachate plume may be

 confined to the landfill site or it may travel large distances; It may be divided Into multiple

 plumes, move into different aquifers and reverse Its direction.  It Is  clear, then, that a

 landfill monitoring program must account  for all possible routes of leachate movement If

 It is to be effective.

 The following series of diagrams illustrate a number of hypothetical hydrogeologic  landfill

 settings.  These diagrams are schematic and only intended to Illustrate general leachate

 flow principals.  Both the geology  and hydrology of the settings are  necessarily somewhat

 simplified over most actual  condition,  however, the general principals Illustrated are still

 valid.  In addition,  such complicating factors as differential attenuation of contaminants

 by subsurface sediments and interference with leachate flow by production wells, have been

 omitted. Clearly if all factors influencing leachate migration from a landfill were consid-

 ered, the number of possibilities would be almost limitless.  And, this is precisely  the

 reason why each  individual  landfill should be subjected to a hydrologic Investigation

prior to the establishment of a pollution abatement or monitoring system.

                                                            LAND SURFACE

                                  CLAY  OR   ROCK
Figure 1.  A single aquifer with a deep water table.  Leachates percolate vertically downward from the landfill
         to the underlying aquifer and then moves downgradient as a bulb or plume in the direction of ground-
         water flow.  The mass of leachates may sink to the bottom of the aquifer if of a heavier specific
         gravity, or float near the top of the water-bearing unit if the leachates are predominately hydrocarbon
         in nature.

''      '
                                       ,    .'   ,  ./LANDFILL
                              -  'fT^p-TTV
                                 /;-» ,. ' _ *  /__* ' *^»
Figure 2.  Landfills located in stream-flat ground water discharge areas and within the zone of saturation
         are always in contact with ground water moving from higher-land recharge areas to the stream
         discharge point.  In such cases, leachates are transported with the ground water to the stream
         where it becomes diluted with normal stream flow waters.

                t  *  LANDFILL
                                FRACTURED  ROCK
                         UNFRACTURED   ROCK
Figure 3. Landfills positioned over fractured rock surface in a high water table area, permit leachates to
        migrate downgradient along interconnected rock fractures to some lower natural discharge area
        or a pumping well.

                                                                            _ CLAY	
  Figure 4 - The landfill rests on a fractured rock surface with a deep water table. Leachate flows into
            and through interconnecting fractures and discharges either at the surface as springs or into
            the subsurface where it moves with the  ground water to some more distant discharge point.

                           LANDFILL  '
                                     i  /
1' //// /fPFAT) /  ' '
Figure 5 - The landfill rests on a layer of marsh deposits (organic materials) underlain by an aquifer.
        The water table is high and a mound is formed at the base of the landfill.  Leachate mi-
        grates downward through the marsh material to the aquifer. Some contaminants may be
        attenuated within the marsh deposits. That portion reaching the water table moves
        through the aquifer with the ground water to some surface discharge point.

                                        ///  /  V
                                     LANDFILL  /
F'9ure 6 " The landf'H rests on a layer of permeable sand interbedded with clay lenses and underlain
         by a clay layer. The water table is deep. Leachate percolates downward under the land-
         fill, forming perched water tables and finally reaching the actual water table.  A series
         of leachate plumes flow around clay lenses with the ground water.

                                                ,'  /TV/—7 /

                                             /LANDFILL '

       Figure 7. An extensive perched water table is formed under the landfill.  Leachate percolates to the perched
                water table and flows downgradient to the end of the confining layer where it may again move down-
                ward to the actual.water table.

                      .   • I  I I T-~ I
                      •  ''/',''  ' '
   ----- CLAY
                                          {   GRAVEL
Figure 8 - The landfill occupies an abandoned gravel pit with a clay layer at its base. A perched
        water table (leachate) will mound up under the landfill and flow laterally through the
        ground above the clay until it is free to percolate to the actual water table.

                                            ,, -.
                                    / I  '   I   ' '
                                  f  f f' ' t', t
                              J',*  '
                      -'.MARSH ^DEPPSjTS^  (PEAT),         ,   _
Figure 9. The landfill lies above organic marsh deposits bounded on either side by streams and underlain by a

        shallow aquifer.  Leachate from the landfill may move horizontally through the marsh materials to

        the stream, or vertically downward with ground-water recharge to the aquifer.

                                                                         WATER  TARLF
Figure 10.  The landfill rests on a single aquifer interbedded with clay lensed.  The leachate plume is split into rwo
          plumes by a clay lense.  One plume discharges near the landfill while the other plume moves deeper in-
          to the aquifer and flows to a more distant discharge point.


- *" /
X ,
\ \ v
_ <1 ' f
FIN IN1'"1-- \

! /•*
— x /
' — ) "'"~" )
.,_ - — — 	 	 ir~
-y xy
/' , /
•^ -
~~ i
/ i
Dpn .


r\ ~\ \~
Figure 11.  The landfill is situated over a two aquifer system with opposite flow directions.  Lea chare
          first moves into and flows with the ground water in the upper aquifer.: .Some of the leachate
          eventually moves through the confining layer into the lower aquifer where it flows back be-
          neath the landfill and away in the other direction.

            /  '/
\ -  \


                                                     LAND SURFACE
                                   - H	WATER
                                    '     ~~~~ ^     7---.                   TABLE
                                                 /   /   , — — —
                                                                             I.OVVFP UNITS
Figure  2
     ' The landfi" is situated over a three aquifer system and a deep water table.  Leachate
      percolates to the upper aquifer where it moves as a plume in the direction of ground
      water flow.  Eventually some of the leachate moves through the confining layer and
      tnto the second aquifer that is an interconnected unconsolidated - creviced bedrock
      water-bearing unit.

    TIL En

                                                        S.LTY  CLAY
                                                PEZOMETRIC   LEVEL
Figure 13. The landfill rests on a thick layer of clay underlain by an aquifer. Leachate is unable to penetrate
         the clay layer and discharges to the surface tile drainage systems or drainage ditches in the area
         	i iL_ i__~ic:ll
         around the landfill.

                                 / //V'/
                             LANDFILI  /
                                                                 LAND SURFACE
                                                    X	~— — _   WATER  TABLE
                                                       ^    SAND
Figure 14. The landfill rests on a single aquifer with a steep, shallow water table which intersects a portion of the
          landfill.  Ground water flows directly into the landfill forming leachate which then flows downward in-
          to the aquifer as a plume.

                                    '/  /  '  /   LANDFILL
WAT I-1- —r —
                                     (LEACHATE  CONTAMINATED
                                       FRESH  WATER)
                                   CLAY    LAYER
                                                                                  (SALT WATER)
             Figure 15 - The landfill is located near a large salt-water body. The leachate plume flows down into
                      the fresh water aquifer and toward the open salt water body. As the leachate plume reaches
                      the fresh-wilt interface, it is forced upward along the interface to discharge at or near the
                      edge of the salt-water body.



The zone of aeration is defined as the materials between land
surface and the water table.  It is through these dry sediments
that percolating waters must move on the way to recharging,  or
contaminating the ground water.  In roost cases involving landfill
contamination, unless 1) scientific research is involved, 2)  there
are unusual geologic or hydrologic considerations, or 3) extremely
toxic chemicals are suspected in the leachate. sampling in the
zone of aeration would not normally be carried out.  Such
sampling is difficult and some of the methods are expensive.
However, when the decision has been made to monitor water quality
in the zone of aeration, the depth to water becomes important.
When surface active materials such as clay and silt are present,
attenuation will take place.  Consequently, the chemical
quality of leachate just below the landfill may be many times
worse than that sampled at the water table.  (See chapter 3.5 -for
a detailed discussion of attenuation)

5.1.1 Soil Analysis

Soil analysis can be valuable as a monitoring tool for  tracing
leachate constituents, particularly those prone to cation
exchange or other adsorption reactions.  Collecting soil cores
beneath the landfill can be done as part of  a well installation
process.  Techniques for core collecting are available  (Hyorslev,
1965) , and methods  for soil analysis  are also documented (Black,
1965a, b; Hanna, 1964; Soil Science Society  of America, 1971).

Soil analysis has had only limited use in leachate

monitoring programs for seve'ral practical reasons.  Probably

foremost is the lack of commercial soil testing laboratories

which can handle

                                                              f~ 2.
soil tests outside  the  scope  of agricultural application.  For

example, testing  laboratories are established in each state for

soil fertility analysis (nitrogen, phosphorus, potassium, pH),

but heavy metals, organic  matter, and exchangeable cations are

not accomodated.  In many  places only noncommercial samples are

accepted by these labs.

Another restriction in  soil analysis is inherent in the methodology.

What is actually  analyzed  is  seldom the total soil, but instead,

a chemical extract  of it.  Fundamentally, a separation of the

inorganic/organic matrix and  chemical species in soil solution

or "available" to soil  solution must be made.  An analysis of

the complete soil including the inorganic matrix would be

meaningless.  To measure the  chemical species in solution,

exchangeable to solution,  available to plants, or accumulated by

adsorption or precipitation on the inorganic matrix is the

objective of the  soil analyst.  To meet this objective, soils

must be treated with reagents of differing chemical reactivity

under a variety of  physical conditions.  The resulting solutions

are then analyzed for the  chemical species of interest.

Interpretation of results  is  a function of soil characteristics and

analytical methodology.  Although methods have been standardized

to a degree, the analyst must be able to adapt and interpret

according to the  dictates  of  the soil sample.  In contrast, water

samples are usually analyzed  directly or with a minimum of

pretreatment.  This is  not to state that there aren't analytical

with water samples, but it takes an additional analytical

step to bring a soil sample to the same state that a

water sample is in when collected.

Soil samples yield information which cannot be obtained

from water samples.  Therefore, soil sampling has a place in

the leachate monitoring program, and its incorporation should

be expanded.  Chemical species associated with soil

solution as well as those on exchange sites can be traced

downward in a soil profile or in the unsaturated zone.

Locations of accumulation or leaching can be identified.

Sulfate  (SO4 ), chloride  (Cl ), and nitrate  (NO^) are

soluble and unaffected by cation exchange reactions in soil.

This results in mobility impeded only by the restrictions

of water percolation.  These anions can be analyzed for

in soil samples in addition to  cations which are generally

more strongly associated with  the  solid soil matrix.  The

latter present more difficult  analytical problems because

they must be released  from the  soil matrix prior  to

determination.  However,  locations of  zones  of  heavy  metal  or

phosphorus  accumulations  can only be detected through soil


In addition to the chemical  information obtained from soil

core sampling, mineralogical  information  can be gained by as

simple a means as  visual

observation.  Organic matter layers, clays, or silts nay be encountered.

Knowledge of  their locations will aid ir. interpreting flow patterns and

checiical configuration in the pluae.  If a siore sophisticated analysis is

da sired, s. necbanical analysis can be made relatively easily.  It is sinply

a size fractionatioa of the soil into its respective proportions of sand,

silt, and clay.  Even xsors elaborate x-ray crystallographic analysis of

clays -will identify the clay type.  This latter degree of sophistication

is beyond the scope required for anything but a research progajp. on leach-

ate production and movement.

Advantages and disadvantages of including soil analysis in a monitoring

program are sucaarized below.

      Advantages                                    Disadvantages

1) Ease of soil sample collection     1) Constercial laboratories capable of
                                         non-agricultural soil analyses are
2) Inexpensive saaple collection         scarce

3) Accurate vertical and area! sarap^  2) Hot a proven standardised saapliug
   ling locations                        method for eonitoriKg progrsaa

**} Best nethod to measure leachate    3) Cost of analysis likely to be higher
   attenuation through adsorption or     per saaple than water because of
   precipitation mechanisms *            two-step analytical procedure

5) Long interval between sampling     *0 Applicable nainly in the zone of
   possible because of intermittent      aeration
   leachate production
                                      5) Requirss special equipment for each.
6) In situ conditions of saatple can      sample collection
   be maintained with proper handling
                                      6) Analytical nethods not adaptable
7) Physical and chemical conditions      *» higa-rate standard  procedures  as
   throughout unsatorated zone can be    available for vater
                                      7) Results help interpretation  of vatar-
8) Only part  of total sample needs to    quality data,  but do not replace
   be consuaed in analysis               water-quality data

9) SaCTlos can be stared for later
   comparison or further analysis

        Advantages                                   Disadvantages

10} Mora representative biologi-      8) Wetting and drTing cycles, and
    cal sampling possible than          changes in redox poter.tal can
    •with, water                          changa chsoieal reactivity of soraa
                                        soil constituents after collection

                                      9) Stats-cf-ti.3-art,  not documented
                                        in leachata studies

Decisions regarding adoption of soil sampling in a sionitoring prograa will

   made on the basis of the following criteria.

      1) Relative cost of soil analysis and water analysis fros the zone of

      2) Availability 'of analytical facilities.

      3) Availability of analytical techniques for the parameters of

      **•) Applicability of inforaation.derived to the conitoring progrsa.

      5) Compliance with govermaeatal regulations govemiog monitoring

Hanna, W. J.   196^.  Methods  for cheiaical analysis of soils.  Pages
      in Firaan E. Bear ed.   Cheristrr of the soil.  American Chesiical
      Society Monograph Series !;o.  160.  Reinhold publishing  Co., 1,'sw York.

Soil Science  Society of America.  19?1.  Instrumental cethods for analysis
      of soils and plant tissue.  Madison, Wisconsin.  222  pp.

Black, C. A.  ed. 19o5a. Mathoda of  soil analysis, pare i.   Physical and
      nineralogical  properties including statistics of r.easurscent and
      sampling.  Soil  Science Society of Aeerica, Hadison, Wisconsin.  ??0

Black, C. A.  ed. 19o5b. Methods of  soil analysis, part 2.   Cheslcal and
      microbiological  properties.   Soil Science Society of  America, Kadison,
      Wisconsin. 802  pp.

                              REFERENCES CITED
1.  Block, C. A. ed.  1965o.  Methods of soil anal/sis, port 1.  Physical and mi n era log-
    ical properties including statistics of measurement end sampling.  Soil Science
    Society of America, Madison, Wisconsin.  770pp.

2.  Black, C. A. ed.  1965b.  Methods of soil analysis, part 2.  Chemical and micro-
    biological properties. Soil Science'Society of America, Madison, Wisconsin.
    802 pp.

3.  Hanna, W. J.  1964. Methods for chemical analysis of soils. Pages 474-502 ir^
    Firman E. Bear ed.  Chemistry of the soil.  American Chemical Society Mongraph
    Series No. 160.  Reinhold Publishing Co.,  New York.

4.  Hvorslev, M. S.  1965.  Subsurface exploration and sampling of soils for civil en-
    gineering purposes.  Engineering Foundation,  United Engineering Center,  New York.

5.  Soil Science Society of America.   1971.  Instrumental methods for analysis of soils
    and plant tissue.  Madison, Wisconsin. 222 pp.

5.1.2. Pressure Vacuum Lysiroeters


Suction lysimeters have been used by a variety of investigators,

including engineers, soil scientists, and hydrogeologists, to

obtain samples of in-situ soil moisture.  They are used

predominantly in the zone of aeration, but can easily be

used to sample ground water.  This device, in its most improved

form, consists of a porous ceramic cup capable of holding a

vacuum, a small-diameter, sample accumulation chamber of

PVC-pipe and two sampling tubes leading to the surface.  Once

the lysimeter is emplaced, a vacuum is applied to the cup.

Soil moisture moves into the sampler under this gradient, and

a water sample gradually accumulates.  Then, the vacuum is

released and pressure is applied forcing the accumulated water

to the surface through the sampling tube.  Construction,

installation, and sampling procedures are described by Grover

and Lamborn, 1970; Parizek and Lane, 1970; Wagner, 1962; Wengel

and Griffen, 1971; and Wood, 1973.

The technology of lysimeter utilization  is well  established.

They have been used to  trace; pollution  from  septic tanks  (Manbeck,

1975)y and cesspools  (Nassau-Suffolk Research  Task Group,  1969),

synthetic detergents  (Department of Water Resources,  The

                                        ci fsi'i. '• ••• ~  "•
Resources Agency of California,  1963) /""the colliery  spoil heaps

 (James, 1974).  Apgar and  Langmuir (1971) used suction lysimeters,

wells, and soil samples  to study the movement and  chemical

characteristics of  leachate  from a landfill  in centi \1

Pennsylvania (Figure 5-1).   There the water table  is more  than
200 feet below ground surface,  and monitoring  the  unsaturated
zone is of great importance.  To do this,  the  landfill
excavation was graded and lined so that leachate would drain into
a percolation trench along one side.  The lysimeters were
installed underneath this trench.  As many as  four lysimeters were
emplaced at selected depths in a single borehole to a  maximum
depth of 54.5 ft, each installation separated  from the next by
a pelletized bentonite seal.  Water samples collected  from the
lysimeter network were analyzed for Eh, pH, temperature, specific
conductance, BOD, CJ, SO4/ total alkalinity, NH3, NO , NO3, PO4/
Ca, Mg, Na, K, and jTotal Fe.  Apgar and Langmuir were able to
define differences  in leachate concentration from upslope and
downslope cells  as  well as  leachate attenuation and rate of
movement.  Wood  (1973) suggested a modification of the  lysimeters
used by Apgar and Langmuir  so that water  samples could  be
recovered from any  depth  (Figure 5-2).  With this modification,
deep pressure-vacuum lysimeters  appear to be the best method of
monitoring the zone of aeration  because  a check valve prevents
pressurization of the porous cups.   Pressure exceeding  about one
atmosphere in the sample  chamber would drive accumulated
water  back through  the cup  rather  than to the  surface in  deeply
placed lysimeters.

         ,}  \.         ,
                                                                                                                         • 2-V/cy Pump
                                      su-n     SL-T           st-8  su-9        st-ii
C& vv>,<.\\ -. \  TV

/V v. \:>rv. r< -'^ ,./

i -IT1


* * • " * "
- . - *.


•'• -
-28 S'


Croji section of
                                                               cell lysimeter netwoi;<.
                                                                                                                        "Tubinj"'  Pceisure-	!| ij
                                                                                                                                  Vacuum in   '""j 'j

                                                                                                                                         :'i_  ' c   £
                                                                                                 I^fir-Cross-section of a typical pressuns-vacuum (ytimeter insul.'ation
                                                                                                •fiin>7)i.Wiih ih*i y MI in 11 nmmmigi JLidiahQ^Baania**4^'**^
                                                                                                                                        V \  A-  o


                                                       ~- 9.

Parizek  and Lane  (1970)  have described in detail pressure-

vacuum lysimeter  installation and sampling procedures.  The

following is excerpted from their report:

      "A  typical pressure-vacuum lysimeter installation is

shown in Figure 5-1.  Placement holes are first drilled to

the desired depth.  They may be 4 to 6 inches in diameter

depending upon the number of lysimeters to be placed in

each  hole.  A plug of wet bentonite clay is placed in the

bottom of the hole to isolate the lysimeter from the

undisturbed soil  below it.   This plug is optional.  A layer

of "Super Sil" at least six inches deep, is placed on top

of the bentonite.  "Super-Sil" is the trade name for a

commercially available,  crushed, pure silica-sand of almost

talcum powder consistency.   This is used to provide a clean

transmission medium for soil moisture moving under capillary

pressure, to insure hydraulic contact of the adjacent soil

medium with ih^Jre porous tip,  to fill uneven voids created

during drilling,  as well as  to discourage clogging of the

ceramic  tip by colloids,  organic matter, or soil particles.

The lysimeter is  placed in  the hole to the desired depth,

and "Super-Sil" is placed around it until the lysimeter is

about half-buried.  Native  soil, free of pebbles and rocks,

is backfilled and tamped with long metal rods.  After the

lysimeter is covered  with about six inches of soil, a second plug

of bentonite is deposited to further isolate the lysimeter and

to guard against  possible channeling of water down the drill

hole.  Backfilling is continued with native soil  to the

depth where it is desired tp set the next lysimeter, at which

point the above procedure is repeated.

It was found that three lysimeters were the most  that could

be conveniently placed in any one six-inch diameter hole.

If more than three were installed this led to difficulties

in proper depth placement, prevented proper tamping of

backfill material, added to the danger of crimping or

tangling the copper tubing and to the risk of channeling

soil water down the incompletely filled hole.  Care was taken

to accurately measure the depth of placement of each lysimeter.

It was possible to set the lysimeters to within six inches

of the desired depth even in 30-foot deep holes.

After the lysimeters are placed, a short section of

flexible tygon plastic tubing is secured over the end of each

copper access tube with PVC electrical tape to allow

thumb-screw pinch clamps to be used to seal the lysimeter

between sampling periods, thereby maintaining the vacuum

within the lysimeter.

The pump used in conjunction with these pressure-vacuum

lysimeters is a two-way hand pump that can either  deliver  a

back pressure or pull a vacuum.  This pump can be  purchased

from any laboratory equipment supply house.  The pump  is

similar to a tire pump.   It has  a base on which  the operator

may stand while working  the pump.  A small vacuum gauge may be

installed on  the vacuum  part of  the pump by means of a

tee-union.  This enables the operator to consistently apply

a desired vacuum to  all  lysimeters  (about 18 inches of mercury)

A length of tygon  tubing is secured to each of the pump's

pressure and  vacuum  parts to allow the pump to be coupled to

the access tubes of  the  lysimeters.  The free ends of the

pump's tubing are  slipped over a short length of copper

tubing that is secured to the pressure-vacuum tube of the

lysimeter and is held securely by a small spring-loaded clamp.

A typical pressure-vacuum lysimeter sampling sequence is

as follows:

     1. The lysimeter*s  discharge tube is clamped shut and

        the vacuum side  of the two-way pump is attached to

        the "in" tube.

     2. A vacuum of  approximately 18 inches of mercury is

        drawn and  the "in" tubing is clamped shut.

     3. To recover soil  water samples, the pinch clamps are

        removed and  the  pressure side of the two-way pump

        is attached  to the lysimeter's "in" tube.  A

        few strokes  of the hand  pump generates enough pressure

        to force the water out of the lysiraeter and into a

        collection bottle placed under the discharge tube.

     4. After emptying the lysimeter the discharge tubing is

        clamped, the vacuum side of the pump is attached to

        the "in" tube and the lysimeter is evacuated again

        to gather  another sample."

Advantages and disadvantages  of  the  pressure-vacuum lysimeter
are given below:	

1. Inexpensive sampling devics of

   great reliability.

2. Inexpensive installation

3. Standard water analysis can be  made

5. Samples can be collected at a

   central point

1. Moderately complicated

   sampling procedure and


2. Sampling device

   failure is irrepairable

3. Small volume of sample

4. Surface tubing subject

   to tampering unless

   adequately protected

5. Use at depth greater

   than 108 ft, not


6. Sample contamination

   by porous cup if

   material is not

   properly prepared

7. Possible plugging of

   cup by colloidal

   materials, and cup

   might exclude large


                                                                                 - I i. ••<•
                               REFERENCES CITED
  1.   Apgar, M. A., and D. Langmuir.  1971.  Ground water pollution potential of a
      landfill above the water table.  Pages 76-94 in_Ground Water, Vol. 9, No. 6.

  2.   Department of Water Resources, The Resources Agency of California.  1963.
      Annual report on dispersion and persistence of synthetic detergents in ground water,
      San Bernardino and Riverside Counties. A report to the State Water Quality Con-
      trol Board, Interagency Agreement No. 12-17.

  3.   Grover, B. L., and R. E. Lamborn.   1970.  Preparation of porous ceramic cups to
      be used for extraction of soil water having low solute concentrations.  Pages 706-
      708 [n_Soil Science Society of America Proc., Vol. 34, No. 4.

  4.   T. E. James.  1974.  Colliery spoil heaps in_J. A. Cole, ed.  Ground water pol-
      lution in Europe.  Water Information Center, Port Washington,  New York.

  5.   Manbeck, D. M. 1975.  Presence of nitrates around home disposal waste sites.
      1975 Annual Meeting preprint, Paper No. 75-2066.  American Society Agricultural

 6.   Nassau-Suffolk Research Task Group.  1969. Final report of the  Long Island ground
      water pollution study.  New York State Department of Health,  Albany, New York.

 7.   Porizek, R. R., and B. E. Lane.  1970. So! I-water sampling using pan and deep
      pressure-vacuum  lysimeters.  Journal of Hydrology, Vol. 11.  pp 1-21.

 8.  Wengel, R. W., and G. F. Griffen.   1971.  Remote soil-water sampling technique.
      Soil Science Society of America Proc., Vol. 35, No. 4. pp 661-664.

 9.   Wagner, G. H.  1962. Use of porous ceramic cups to sample soil water within the
      profile.  Soil Science, Vol. 94.  pp. 379-386.

10.   Wood, W. W. 1973.  A technique using porous  cups for water sampling at any
      depth in the unsaturated zone. Water Resources  Research, Vol. 9, No. 2.
      pp. 486-488.

                                                r- 13.
5.1.3 Trench Lysimeters


Several investigators have used trench lysimeters  to sample

gravity water from irrigation or rainfall in the near-surface

zone of aeration.  In normal practice/ a wood-reinforced

trlinch or concrete-ring caisson is installed to a  depth of

10 to 30 feet below land surface.  Pans (Parizek and Lane,

1970) , t*oughs (Olin Braids, personal communication,  August

1975) , or, open end pipes (Nassau-Suffolk Research Task

Group, 1969) are forced out of the trench (caisson), through

access ports, into the subsoil.  These collecting  devices

intercept^ percolating gravity water and conduct  it to sample

bottles inside the trench.  Only after irrigation  or precipitation

is there enough water infiltrating the subsoil to collect a

sample.  Figure 5-3 shows an installation used to collect cesspool


Due to the potential accumulation of hazardous gases generated

by decomposition of landfilled material, the use of an open

trench or caisson to sample leachate  in or under a landfill

can be risky.  Artificial ventilation  and gas monitoring

devices are required to prevent  injury to personnel collecting

samples inside the trench.


A description of a typical tranch  lysimeter  is excerpted  from

Parizek and Lane  (1970).  "A 4-foot wide, 12-fnt long trench

1 <
1 L»

•l-~"s:u~~. 1 	 ; 	 1 ••£*?i.~ y/«-
hr ii
r t
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i f i i
I 1 1 !- 1 1
1 ! ! !
1 1 1
r .
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^T"^ —
1 1 i

TEN 510 METER 	 y
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	 ^-= 	 : 	 ' 	 	 	

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U1""' ' VACUUM

< .
"" * Jl
• —\
• -^

. WATER TABLE 23 -6" JUNE'63
-, |

WATER TA3LE 2S'-5" DEC oo *••
~i55c£o£ - SecHon hhroug'n a cesspool and nearby sampling cnc.-n'asr showing th& lacaricr
of tsnsio.Tief'ers and grcvify samplers used to scmpie-. cesscoal effluenr in Lcr-

                                                       .r- 14,
was  excavated to a depth of 10 feet using a back hoe.  The hole

was  braced with timbers and siding to allow safe access to the

trench.  The trench was then hand-dug to a 17 foot depth and

braced.  The entire seepage face was inclined 1 to 5 degrees

from the vertical and sloped toward a hill down which soil water

and  interflow was expected.  The residual soil contained

resistant chert and quartzite cobbles and boulders and was

reasonably well "cemented" with iron-oxide and clay.  As a

result, the pans could not be inserted into the soil profile

without first providing an opening.  A sheet metal b.Slae 4 inches

wide and 2 feet long was hammered into the overhanging bank with

a sludge hammer to provide access for the pans.  Pan lysimeters

were tapped into these openings and allowed to slope gently toward

the trench.  Voids above and below the pans were back-filled with
        /' w s-
soil andftamped into place.  As siding was added to the trench

walls, holes were cut to allow the copper tubings to project into

the sampling pit.  Spaces between the original trench faces and

siding were filled with native soil and washed pea-gravel to allow

water to flow freely toward the pit floor (Figure 5-4) .  After the
walls and braces were emplaced, tyjge& tubing was connected to the

copper tubing and inserted into plastic sampling bottles.  The

sampling pit was covered with a sloping roof and a half-round

drain pipe was /Sued to divert roof water away fron the

installation.   A ladder was placed at one end of the house to allow
An alternative method of construction is to place concrete manhole

rings in an open excavation or to sink them to depth using caisson

construction techniques, depending on soil stability.   This

                             2x12" Siiing eni
                             4x4* Tinbers. i'.l Wsod
                             TrtoUd with Pr*isr«:iv».
                                         Gutter Cram
                                         '  Pip*

                            nf tn-TTi

                                                       - is.
type of construction is shown in Figure 3.

Trench Lysimeter Comparison Lysime.ter

Advantages                            Disadvantages

l.None                                1. Dangerous because of


                                         possible flamable gas


                                      2. Water will flow to

                                         samples only after rainfall

                                      3. Considerable expense

                                         involved in constructing

                                         trench or caisson

                                      4. No documentation of

                                         application  to landfills

                              REFERENCES CITED
1.   Nassau-Suffolk Research Task Group.  1969.  Final report of the Long Island
     ground water pollution study.  New York State Department of Health, Albany,
     New York.

2.   Parizek, R. R., and B. E. Lane.  1970. Soil-water sampling using pan and deep
     pressure-vacuum lysimeters. Journal of Hydrology, Vol. 11.  pp. 1-21.

                                                      J- 16.

 IP. the zop.e of saturation, leachate movement from a landfill will be

 controlled by a combination of ground-water flow patterns and soil-

 leachate interactions.  Under shallow water-table conditions, only

 a small zone exists where unsaturated soil-leachate interactions can

 reduce leachate concentrations.  Therefore, careful collection of

 representative ground water samples from property constructed

 wells is necessary to trace leachate movement or determine its

 presence in the ground-water environment in which the landfill is

cT'Jell Screened or Open Over a Single Vertical Interval


 Wells screened over a single vertical section of an aquifer, are the

 most common construction used to obtain ground water samples from

 unconsolidated sediments or semiconsolidated rocks.  Uncased

 wells (open hole) in consolidated rock can be used for the same

 purpose.  Although this type of well is routinely used in monitoring

 ground-water contamination, including landfill leachate (Anderson

 and Dornbush, 1968 and Fungar&li, 1971) a single well is not

 particularly effective in providing information on the vertical

 distribution of a contaminant.  In practice, a well is drilled to an

 arbitrary depth, usually just below the water table in landfill

 studies, and the screen is set so that it intersects the water table

 (Figure 5-5).  The rationale for this type of construction isl^if

 leachate reaches the ground water, it will be detected in water

                                    CEMENT  GROUT 1-3 MIX,
                                    OR BENTQNITE
                                C^-GRAVEL PACK
 r 4" SCREEN
 V: (GATOR   \J
. ,-^, (    r-r r. -,--'"-> "2* fT I         %
  i ;.
•« -.;'\' i
                       NOT TO SCAll

                                                          ~ 17.
samples from this type of well.   However, this construction is
often used when leachatc has already reached the ground water.
The drawback of the construction is immediately apparent;  only a
portion of the aquifer is sampled and only the most recently infiltrated
leachate can be collected.  In most cases, leachate will be
denser than water and sink into the ground water under partial
control of a gravity gradient.  This denser fluid body, "sinking"
into fresher water cannot be sampled with a well that skims only the
top of the water body.  However, in the experience of the writer,
great reliance has been placed on this type of well construction
to trace the extent of leachate movement into an aquifer.

Even if the well is completed below the water table, it may not
provide water samples representative of leachate concentration at
that point.  For example, the well casing may entirely seal
off the contaminated acquifer or the screen may penetrate into
another aquifer system (if little is known about site geology),
thus providing misleading water -samples.  This drawback can be
partly counteracted .if the well is screened over the entire aquifer
thickness; however, if the aquifer is thick and the contaminated
plume is thin, the composite ground water sample that is
obtained provides no information on the vertical distribution of

Taking everything into consideration, using a single-screen well
appears to be justified under two situation: 1) obtaining composite
ground water samples from wells in which the entire saturated
thickness of the aquifer is screened and 2) areas where depth to
water is great and the majority of the sampling program is aimed

 at the zone of aeration and the top of the  zone of  saturation.
 The latter case is probably the best use  of this  type of well.
 The wells, completed in the upper zone of the water body, would
 serve as an early warning system if any leachate  is able to
 percolate to the ground water.   Once detected, other sampling
 techniques would be required to trace leachate extent and
 movement in the aquifer.
This  type  of well can be  drilled by a variety of techniques,
including  mud-rotary, reverse-rotary, air-rotary, jetting,
augering,  and  drive points; warfeh diameters rangia? from 1 1/4
inches to  greater than but rarely exceeding 36 inches.  The
drilling method  chosen depends on:  1)nature of material to be
penetrated,  2) diameter and depth of well desired, 3) site
accessibility, 4)  availability of drilling water, 5) budget
constraints, 6)  time constraints and a variety of other factors
resulting  from individual  site conditions.  Drilling methods per
se are discussed in a later section,  but a summary is presented
in Table 1.  With the possible exception of hand augering and
drive points,  a  drilling contractor should be used to install this
type of well unless the investigator has access to a power auger,
soil boring, or  jetting rig.

                                                         .> • / 6 fl
Weft -Is*; Serened Ove-f^a' Single ^Verti-fcal In.fer.fral-.

To be able to compare costs of the various techniques

described in Chapter 5.2..  A hypothetical aquifer is required.

For the purposes of illustration, a water-table aquifer

composed of unconsolidated sand with a depth to water of

10 feet and total saturated thickness of 100 feet will be

used.  However, it should be realized that these cost estimates

are based on prevailing rates in the northeast and consequently

actual costs will be lower or higher^ depending on conditions

in the investigations' local area.  Also, drilling and

materials prices have been climbing recently and the costs

presented here  (Fall 1975) will no longer be representative

e£-aiLuul co&Ls in a very short period of time.  In spite

of this, these estimates will provide an idea of relative

cost that should remain relatively unchanged by inflation^

etc.  Table 1 is a summary of these costs.

As mentioned in Chapter 4.2, the recommended type of con-

struction for monitoring purposes is to screen the well

over the entire saturated thickness  of the  aquifer, which

                                      **   1-
in our example is 100 feet.  The quicktfesg  and least

expensive way to complete this type  of installation would

be to drill a 6- to 8-inch diameter borehole with a hydraulic

rotary rij to the bottom of the aquifer; set 4-inch diameter

                        Table 1.  Cost Estimates for Various Sampling Methods

                                                          Price Per Installation
                                                             Well Diameter
 Sampling Method	2-inch	4-inch	6-inch	

 Screened over a single interval
 (plastic screen and casing)

     1.  Entire aquifer                       $1,600 - $3,700   $2,300-54,500   $6,400 - $7,500
     2.  Top 10 feet  of aquifer                    650-  1,050       700-  1,150
     3.  Top 5 feet of aquifer with drive
         point                                   100-200

 (plastic screen and casing)

     1.  Entire aquifer screened
          a.  Cement grout                   2,10Q -  4,700    2,800-  5,500    6,900-  8,500
          b.  Bentonite seal                    1,850-  4,150    2,350-  4,950    6,650-  7,950

     2. Top 10 feet  of aquifer screened
          a.  Cement grout                   1,150-  2,050    1,200-  2,150
          b.  Bentonite seal                      900-  1,500      950-  1,600

Well clusters

     1. Jet-percussion
          a.  Five-well cluster, each well
             with a 20-foot long plastic
             screen                          2,500 -  3, 800
          b.  Five-well cluster, each well
             with only a 5-foot long plastic
             screen                          1,700-  2,300

    2.  Augers
          a. Five-well cluster, each well
             with a 20-foot long stainless-
             steel wire-wrapped screen        4,600-  5,300
          b. Five-well cluster, each well
             with only a 5-foot long gauze
             wrapped drive points             1,800-  2,600

                  Table 1 (continued). Cost Estimates for Various Sampling Methods
Sampling Method
Price Per Installation
   Well Diameter
     3.  Cable tool
         a. Five-well cluster, each well
            with a 20-foot long stainless-
            steel, wire wrapped screen

     4.  Hydraulic rotary
         a. Five-well cluster, each well
            with a 20-foot long plastic
            screen, casing grouted in place
         b. Five-well cluster, completed in
            a single large diameter borehole,
            15-foot long plastic screens, 5-
            foot seal between screens

Single well/multiple sampling point
         a. 110-foot deep well with one-
            foot long screens separated by
            4 feet of casing  starting at 10
            feet below ground surface

Sampling during drilling
                                    $ 9,850-$14, 150
                  $9,050 - $ 14,900  13,800 -  19,400
$4,240-$5,880    8,250-   11,000
                                      3,000-   4,700

                    3,000-  4,700   3,300-   5,200

 plotted PVC well screen and PVC casing; backfill with a

 gravel  pack or formation stabilizer;  and place a concrete

 collar  around the well casing at ground surface to prevent

 downward leakage of rainwater or other fluids.  Total cost

 of  this installation is in  the range of $2,300 to $4,500

 for drilling,  materials,  installation and development.

 Screen  is second only to drilling in terms of cost, running

 from $1,000 to $1,500 for 100 feet of 4-inch slotted PVC.

 Cosntruction cost could be  reduced to a total of $1600 to

 $3700   if 2-inch casing and screen are used, but sampling

 can be  more difficult in a  well of this diameter.   On the

 other hand,  using 6-inch casing and screen facilitates

 development and water sampling but elevates the cost to

 the  range of $6400  to $7500 per well.  In wells of this

 size, wire-wound metal  well screens are more commonly used

 than PVC,  resulting in  a  substancial cost increase per

 installation as compared  to the 4-inch well.

 If the  investigator is  interested  in sampling only the

 top of  the  aquifer  with a well  constructed so that a 10-foot

 long 4-inch diameter  screen intersected the water table,

price per installation  would  range from $700 to $1200.

This is  a substantial reduction in expenditure required

to monitor  the  ground water,  but  as discussed above, it is

not a completely reliable technique for assessing ground

water contamination by leachate.   Even greater reductions

in expenditure per installation can be obtained by installing

a 2-inch diameter, 5-foot long drive point by hand, total

cost of which would be less than ?200 per well including

labor, materials, and development with a pitcher pump.

Table 1 - Summary Table of Drilling Methods

Cable Tool
Drive Point
Shallow Moderate Deep
0 -200ft. 200-1 000ft 1,000ft


Small Moderate Large l'-
l-4in. 4-1 2in. 12 in'.'




                                                                Complexity  of  Operation
                                                                       Moderate     High
                                                                          X    to     X

                                                                          X   to     X

                                                                          X   to     X

                                               jT-  19.

1. Inexpensive

2. Small diameter, shallow wells

   quick and easy to install

3. Can provide composite ground

   water samples if screen covers

  saturated thickness of aquifer

4. Can be drilled by a variety

   of methods

1. No information on

   vertical distribution

   of contaminant

2. Improper completion.

   depth can give

   incorrect picture of

   leachate distribution

3. Construction method

   can contribute to

   vertical movement

   of contaminant

                              REFERENCES CITED
1.   Anderson, J. R., and J. N. Dornbush.  1968.  Investigation of the influence of
     waste disposal practices on ground water quality. Water Resources Institute, South
     Dakota State University, Technical Completion Report.

2.   Furgaroli, A. A.  1971.  Pollution of subsurface water by sanitary  landfills. U.S.
     Environmental Protection Agency Report SW-12g.  186pp.



Although the terms piezometer and observation well  are  commonly

used interchangable, there is a significant difference  between

them. As implied by its naitie, a piezometer is a pressure  measuring

device, frequently used for monitoring:  1)  water pressure in earthen

dams or under foundations, and 2) artesian pressure in  confined

aquifers.  The piezometer, a porous tube or plate in the  former  and

a screened well or open hole in the latter, is isolated from other

pressure environments by an impermeable  seal of either  clay or

cement.  Water samples representative-of a specific horizon can  be

obtained from well-type piezometers, a highly desirable factor in

designing a monitoring program (Figure 5-6).  Piezometers can also

be used to measure vertical head differences under unconfined

conditions if the well screen is properly isolated by an impermeable

seal immediately above the screen.  Any well constructed without this

seal cannot be considered a piezometer.   However, there is a

significant difference in application to landfill leachate monitoring

between a piezometer and a well screened over a single vertical interval,

The relatively impermeable annular seal will prevent; downward

movement oc leachate into uncontaminated zones of the aquifer.

A low-ccst modification of a typical engineering piezometer will

allow collection of in-situ ground water samples throughout the

saturated thickness of an aquifer.  The piezometer, on modification,

resembles the deep pressure-vacuum lysimeter described above  (Figure

5-7).  However, porous PVC is used instead of a ceramic  cup, which

is not necessary and would,  in fact, decrease the  effectiveness of






. •'.











.':/-«— CONCRETE

^T" ";- i-
«fcr— tMPERViOUV
/OIL/ //
	 z"pvc sea 40-

2" PVC SCH. 40



•— —

•— —

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•Eif^te1 Piezometer installation for shallow ground-water
monitoring around sanitary landfills.

Geraghty & Miller,
 .  .  e*fiy) v
      ':" -o r- ^'

the sampler.   With porous  PVC,  a vacuum applied to the sampling

chainber is  immediately transmitted  to  the aquifer, drawing

water into  it.   & porous ceramic cup holds a vacuum and water

slowly moves  through  it, a characteristic necessary to collect

soil-water  samples.   Using porous PVC  (or even slotted PVC)

should substantially  reduce the cost of the sampler below

the approximately $30 charge for commercially available deep

pressure-vacuum lysimeters.   The surface sampling procedure is the

same as that  for a pressure-vacuum  lysimeter.


In order to place a grout  or bentonite seal around a well

casing as required in piezometer construction, there must be

an annulus  between the casing and the borehole wall.  This

limits drilling methods to (1)  cable tool, (2) one of the

rotary techniques or  (3) hollow stem augering and a drilling

contractor  will be required.  After casing and screen have been

installed,  a  gravel pack is placed  around the screen.  To seal

the well casing,  a neat cement  grout or bentonite slurry is

poured or pumped into the  annulus,  thus preventing the

vertical leakage that might occur in the annulus if the well

is merely backfilled  with  cuttings  or  fill.  This seal is vital

from a sampling standpoint,  because the sample withdrawn from

the well is from a known vertical interval of the aquifer.

Without the seal,  rainwater would infiltrate backfill, potentially

diluting samples collected from the well or leachate could move

downward, causing samples  to be non-representative.  Another

consideration is that the seal tends to prevent downard

movement of leachate in the annular material which may

act as a conduit to uncontaminated zones of an aquifer.

Constructing a monitoring well that contributes to

or hastens the spread of contamination is not a

recommended procedure.


Since piezometers  and wells  screened over a single interval

are the same except  for  an impermeable seal between the

casing and borehole  wall, the only price difference will

be that incurred for placing the impermeable seal and purchase

of necessary sealing materials.  In the hypothetical

aquifer, only a 10 foot  seal is required and a two-man crew
should be able to  place  it in half a day to a day.  This

                 "                    t      *
would increase installation  cost about 500 to 1000 dollacs-
1. Point sample is collected from
   a known vertical section of
   an aquifer
2. Construction prevents downward
   migration of leachate in borehole
3. Can be installed inexpensively and
   rapidly if casing diameter is small
4. Can provide composite ground-water
   samples if screen covers saturated
   thickness of aquifer
5. Modification of an engineering
   piezometer will allow vertical
   sampling of contaminant
1. Restricted number
   of drilling methods
2. No information obtained
   on artificial is «•' f/'f * t
   distribution of
3. Improper completion
 .  depth can give
   incorrect picture of
   leachate distribution

                             REFERENCES CITED
1.  Clark, T. P.  1975.  Survey of ground-water protection methods for Illinois land
    fills.  Ground Water, Vol. 13,  No. 4. pp. 321-331.

 5.2.3 Well Clusters


 The major drawback in using individual wells screened over

 a short vertical distance of the aquifer is that they provide

 no information on the vertical distribution of contaminant and

 only rudimentary information on its areal distribution.  To
 overcome this, investigators (Pitt, 1974; Weist and Pettyjohn

 1975; Aulenback and Toffenmore, 1975; Parlmquist and Sendelein,

 1975; Fryberger, 1972; and Kimmel and Braids, 1975) have used

well clusters to define the vertical distribution of a

 contaminant.  Each cluster consists of a group of closely spaced,

 small-diameter wells completed at different depths in an aquifer

 from which water samples representative of different horizons

within the aquifer can be collected.  Careful placement of well

clusters at the landfill site and its vicinity will allow reliable

delineation of both vertical and areal leachate distribution.

Well clusters are by far the most common and successful technique,

to date, for delineating ground water contamination.  One short-

coming, however, is selection of the completion depth of each well

in the cluster.  Several approaches to selecting this depth have

been made;  1) a pair of wells,  one screened at the top, the other

at the bottom of the aquifer (Burt, 1972, and Geraghty fi> Miller,

1975); a three-well cluster, with screens set on the top, middle,

and bottom of the aquifer under investigation (Weist and PettiJohn,

1975); and 3) clusters in which the screened intervals are separated

by preselected  intervals,  such  as the 10, 20, 30, 40, and 60

foot screen depths used by Pitt (1974) ; the 20 foot separation

from 20  to 100  feet used by Yare  (1975)  (Figure 8) , or

terminating 2 to  3 wells at 10-15 feet intervals as recommended by

Palmquist and Sendelein  (1975).  The fixed sampling depth, whatever

the screen placement  selected,  limits to some degree the usefullness

of the well cluster.

As pointed out  by Yare  (1975) ,  large vertical zones of an aquifer

would not be sampled, dependent on saturated thickness, even if up

to five  wells are constructed in each cluster.  Some uncertainity

will always exist as  to the actual vertical distribution of

contaminant.  Construction of more wells per cluster is not the

answer;  only so many  wells can  be constructed close enough together

to represent vertical contaminant distribution at one point.  In

addition, construction cost as  well as the time required to complete

the cluster would become prohibitive.  The only way to get a "true

to life" as possible  picture  of leachate distribution is to collect

ground water samples  during drilling, a technique described below.


Well clusters are easily installed, a major factor to be considered

when designing  a  leachate  monitoring system.  Normally, in

unconsolidated  sediments,  small-diameter steel casing  (2-2 1/2 inches)

is driven by the  jet  drilling method to the desired depth and the

screen is set by  the  casing pull-back method or by augering a hole

         *0£PTH tO FT.
                              /DEPTH SOFT
      = PTH TOFT.
                    DEPTH 63 FT.

    i-i ..._ii _•

 and  forcing a well point to the desired depth.  Alternatively,

 a hole  can  be drilled or augered to a predetermined depth and

 a common well point driven out the bottom of  the hole into

 undisturbed sediments.   Either installation technique is

 relatively  rapid and inexpensive.   For shallow aquifers  (20 - 30

 ft) , 1  1/4  inch  well points can be driven by  hand to construct a

 cluster (Aulenback and Tofflemire, 1975).

 Another approach to well cluster construction is multiple well

 completions in a single borehole.   This involves drilling a large-

 diameter hole, either by a rotary  technique or bucket auger, and

 installing  small-diameter wells to selected depths with each

 screened zone isolated from the o'thers by an  impermeable seal.

 Meyer (1973)  completed as many as  3,  four-inch PVC wells in a single

 22 inch borehole and Hughes and others (1971) install up to six

 1 1/4-inch  to 2-inch observation wells in one boring.  This

 technique for constructing wells clusters seems feasible provided

 the cost of drilling large diameter boreholes is not prohibitive

 and care is taken in placing the impermeable  seals between screened

 zones (Figure 5-9).   A great advantage is being able to construct

 the wells close  enough  together to get samples actually representative

of a single point (areally)  in the aquifer, thus increasing the value of

 the data obtained on water quality.   If care  is taken in constructing

 the seals between the individual wells,  such  as using a shrinkage-

 inhibitor in the cement grout,  reliable samples of in-situ ground

water can be obtained, of course,  the  greater  the number of casings in

 the borehole,  the greater the liklihood of imperfect seals between

 the casings.   To insure that the seals are effective, water levels

                  I*:,-  r   •  tfc  u

                  'V  •*!  ^  fe^
                  '^1  i >,i  ^   bt

                  .f'  :^l  *  !<

                  P'-  ®^  H  Is
                          \ '    '-, -1> -J
                            ,—>  'A
   "i  ;o
i  P
I  i  .j
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  1  }  7

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                             .:. O
                                             \  ^»-•-.- -rc-v ^rr.x
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in wells not being sampled  should be checked for sharp drops.

An abrupt drop would tend to indicate a vertical connection between

the screens.

Well CLu's£e.r"s

A variety of drilling methods can be used to install  a

well cluster in the hypothetical aquifer; however, the  best

method is jet-percussion because of the tight seal between

casing and formation and relatively low drilling changes.

This installation, consisting of a cluster of five wells

2-inch diameter with screens from 10 to 30, 30 to 50, 50

to 70, 70 to 90, and 90 to 110 feet below ground surface

would require an expenditure of $2500 to./3800.  If only

5-foot long screens were centered around depths of 30, 50

70, 90 and 110 feet, the well cluster would cost $1700

to $2,300 to install.  However, as discussed above, this

type of construction is not ideal because of the vertical

distances between the screened intervals through which the

plume of leachate enriched ground water might pass undetected.

Another way to construct well clusters in  this  aquifer

would be to use a power auger.   In  this method, a  sediment

is loosened by a  flight of augers and then a  well  point

and two-inch casing  is pushed through the  loosened formation

material to the desired completion  depth.   One  problem

with this construction is the potential  for vertical leakage

of water through  the column  of  loosened  soil around  the

well casing.  Another is that  sturdy,  screens must be used

 in order to withstand the  stress of being driven through the

 loosened  sediments in the  borehole.  In normal practice,

                                                           r - 2 7 B
relatively  inexpensive drive poi^t, five feet or less  in

are used.   However, to monitor the entire saturated thickness

of the hypothetical aquifer, five 20-foot long, stainless

steel wire  wound screens with a drive point will be required,

considerably increasing total cost of the installation.  An

augered five well cluster with 5-foot long, inexpensive

drive points should cost $1800 to $2600 while the most

effective installation from a sampling standpoint with five

20-foot long, 2-inch diameter stainless steel screens would

cost $4600  to $5300, a significant difference.

More expensive alternatives are drilling with either  the

cable tool  or hydraulic rotary method; the former costing

about $9850 to $14,150 per cluster of 6-inch diameter wells

and the lather from $13,800 to $19,400.  The substantial

difference  in these figures is due to the necessity of

grouting the annulus between casing and borehole wall in

the rotary  drilled holes.  Grout is necessary to prevent

vertical leakage of water through the annular material, into

the screen  with leakage, samples would not be representative

of formation water in the screened zone.  Because of  the

seal between casing and borehole wall in a cable tool well,

grouting is not necessary.  No substantial economies  could

be obtained by switching to 4-inch diameter cable tool

holes.  Drilling costs will be about the same as for  6rinch

                                                            -T- Z
 and  the main savings would come fron using 4-inch stainless

 steel wire wound screens rather than 6 inch.

 An alternative to five individual well completions to

 make a cluster is to install multiple casings in a single

 borehole.  This type of installation would cost.^8,200 to

^11,000         for  five 4-inch diameter wells installed in

 a 24-inch diameter  borehole and in the range of $4240

 to $5880 for five,  2-inch wells installed in a 12-inch

 hole.  Because of the necessity of forming a good seal

 between each screen, 15-feet long screens will have to be

 used in the hypothetical aquifer, which allows for a five

 foot seal between each screened interval.  As discussed

 in Chapter 5.2.3, this seal is critical and if not properly

 constructed, anjomalous water-quality samples will



1. Simple installation which does

   not alv/ays require a drilling


2. Excellent vertical sampling if

   enough wells are constructed

3. Tried and true methodology,

   accepted, used in most contamination

   studies where vertical sampling is


4. Low cost if only a few wells per

   cluster are involved, and drilling

   contractor set-up for small

   diameter wells can be found.

1.  Large vertical sections

   of the aquifer are

   unsampled.   Artificial

   constraint  on data  by

   completion  depths - what's

   happening in unsampled


2.  If jetting  rigs or  augers

   are used, installations

   are limited to 125  to 150

   feet total  depth and

   installation is slow.

3.  Small diameter wells can

   be used only for monitoring,

   cannot be used in

   abatement schemes.

4.  Difficult to develop and

   sample if water level is

   below suction lift  in

   small diameter wells.

                               REFERENCES CITED
  1.   Aulenbach, D. B., and T. J.  Tofflemire.  1975.  Thirty-five years oF continuous
      discharge of secondary treated effluent onto sand beds.  Ground Wafer, Vol. 13,
      No. 2.  pp. 161-166.

  2.   Burtf E. M.  1972.  The use, abuse and recovery of a glacial aquifer.  Ground Wa-
      ter, Vol. 10,  No. 1.  pp. 65-71.

  3.   Fryberger, J.  S.  1972.  Rehabilitation of o brine-polluted aquifer.  U. S. Environ-
      mental  Protection Agency, EPA-R2-72-014

  4.   Geraghty, J.  J., and N. M.  Perlmutter.  1975.  Landfill leachate contamination
      in Milford, Connecticut.  Consultants report submitted to General  Electric-TEMPO,
      Center  for Advanced Studies, Santo Barbara, California.

 5.   Huges,  G. M., R. A. London, and E. N. Farvolden.  1971.  Hydrogeology of
      solid waste disposal sites in northeastern Illinois. U. S. Environmental Protection
      Agency, SW-12d.

 6.   Kimmel, G. E.f end O. C. Braids.  1975.  Preliminary findings of a leachate
      study on two landfills in Suffolk County, New York.  U. S.  Geological Survey
      Journal of Research, Vol. 3, No. 3.  May-June,  pp. 273-280.

 7.   Meyer, C. F., ed.   1973.  Polluted ground water:  some causes, effects, controls,
      and monitoring. U.  S.  Environmental Protection Agency 600/4-73-00Ib.

 8.   Palmquist, R.,  and L. V.  A. Sendlein.  1975.  The configuration of contamination
      enclaves from refuse  disposal sites on floodplains.  Ground Water,  Vol.  13, No. 2.
      pp.  167-181.

 9.   Pitt, W. A. J., Jr.  1974.  Effects of septic tank effluent on ground water quality,
      Dade County,  Florida.  An interim report. U. S.  Geological Survey, Open-file
      report 74010.

10.   Weist, W. G., and R. A. Petfijohn.  1975.   Investigation ground-water pollution
      from Indianapolis landfills - the lessons learned.  Ground Water, Vol. 13, No.  2.
      pp. 191-196.

11.   Yore, B. S.  1975.   The use ofa specialized drilling and ground-water sampling
      technique for delineation of hexavalent chromium contamination in an unconfined
      aquifer, southern New Jersey Coastal  Plain.   Ground Water, Vol.  13,  No. 2.
      pp. 151-154.

5.2.4 Single Well - Multiple Sample Points


In order to sample multiple horizons in a single well, screens

or casing perforations must be constructed at regular intervals

in the well.  Spacing will depend on the sample density required

and construction expense; the greater the number of open zones, the-

higher the well costs.   The California Department of Water Resources

(1963) successfully obtained closely-spaced ground-water samples

by perforating steel casing with a mechanical perforator at set

intervals in the well isolating each set of perforations with

inflatable packers, and  pumping the isolated casing segment with a

submersible pump  (Figure 5-10).  The attractiveness of this type of

sampling operation is apparent.  However, there are some pitfalls.

Care must be taken to insure that the packers are isolating the

sampled section of screen and that no water from above or below is

leaking past the packers, contaminating the sample.  Also pumping

rates must be kept low to insure that formation water is drawn from

only opposite the isolated section.  Higher pumping rates will induce

flow from horizons above and below the level of the aquifer being

sampled, resulting in an unrepresentative sample.  If the annulus

between the casing and the borehole wa&e backfilled, the possibility

of vertical movement of  water in the annular area, exists1.

Therefore, there is no guarantee that a sample does not contain water

from a lower or higher horizons' which has moved through the annular

material under the influence of the pumping gradient.  To

adequately protect against this type of sample contamination,  an

impermeable seal of either bentonite or cement grout  should be

                                       SUSPENSION  CAQLE
                                         AIR  LINE
                                               DISCHARGE LINE

                                               RUBBER, DEFLATED

                                                                   \ •>
                                         :.  v ViO

placed  between  every screen or slotted interval.   This  may  not be

possible with closely-spaced screens or casing perforations.  A well
                         Aftt'J-''i$ ~fc  "f/'fje  "t-ft ' •ti'ee.'ft'e -if
constructed and sampled ^^^-'KJ into arrovmt the* ftTwv.y will provide <*
excellent^ samples' af the vertical distribution of  a contaminant.

Another approach^ for shallow vertical sampling using a singlg

is that described by Hansen and Harris (1974).   They isolated fiberglass

probes at  regular spacings inside an 1 1/4 diameter well point  (Figure

11) .  Samples were drawn to the surface through a  tube attached to  the

fiberglass probe after the well point was driven to the desired depth.

This type  of construction is inexpensive and can be "homemade"  with

little difficulty, but will only allow collection  of samples from

depths less than sjerction limit about 30 ft, at sea level.


Installing a multiple sampling point well will require the services

of a drilling contractor unless the device dejcVribed by Hansen  and

Harris  (1974) is used.  This is essentially a drive point which could

be driven  by hand to depths of about 30 feet.   On  the other hand,

multiple screen  or slotted casing installations require the skills  of

a well driller.   For one thing, a large-diameter open  borehole in

which casing can be set is needed, necessitating a cable tool or rotary

rig.  Six-inch diameter or larger casing should be used in order to

accomodate the packer pump unit which in turn requires a tripod winch,

                                   1/4-INCH O D TUBING
            SOIL SURFACE
     t.l/4-IMCH  \
                            SAMPLE COLLECTION FLASKS
                              TU31.NG FROM1,
                              LOWEST PRO3=:
Fig. 1L  Construction details of the groundwater profile sampler.

 po-.ver  and air supply.   If sceel  casing is not slotted before

 installation, a special down hole tool is required to make the

 slots.   Skill and equipment requirements  for this type of

 installation therefore necessitate use of a drilling contractor.

 The  packer/pump is not quite so  formidable.  Once a good quality

 submersible pump has been obtained, local investigators or a

 machine shop can equip it with packers.  Cherry  (1965), has described

 the  design and operation of a rather elaborate packer pump  (Figure

I  "This sampler collects a pumped sample of water from a  specific

  zone in an uncased or multi-screened well.  Minor modification

  of the sampler permits remote measurement of several chemical and

  physical characteristics of the water in the zone being sampled.   The

  sampler can be used in wells with diameters of 8 to 16  inches,

  inclusive, which do not contain pumps, pipes or other obstructions.

  It is suspended on a cable from an A-frame, and is raised and

  lowered by an electric motor that is powered by a 110 volt

  a-c portable generator.  This generator also runs the electric

  pump which is part of the sampler.

  The sampler consists of two inflatable packers or boots - one mounted

  above the submersible pump and other below it.  When the boots are

  inflated, the zone between them is isolated from the remainder of the

  we] 1 and water can be pumped from this isolated zone.

           Fill  Drain  Pump Main
          vatve vatv»
 1. Metal plat.  '
 2.'Wp«..    ;
 3. Electric cable
 4. Inflatable boot (rubber)
 5. Pipe (to inflate boQt)
 6. Plp» (connects two boots) '
 7. Submersible-pump irrtjke
 E. Pressure sensor
 9. Electric till valve (normally closed)
10. Electric drain valve (normally open)
H. Pressure-relief valve (optional)
12. -Flow-regulation valve
                   NOT TO SCALE
                                          SIDE VIEW
            FIGURE 1.—The Casee sampler.
                                                        .r- 32.

The capacity of the pump is about 15 gallons per minute.   The

spacing of the boots can be varied by using different lengths of

connecting pipe between them.  The minip.uzv spacing of the boots is

5 feet  (length of pump) .  The boots are inflated by pumping water into

them, from the well, through an electrically controlled valve; they

are deflated by pumping the water out of them through another

electrically controlled valve.  Advantages of this sampler over

other packer-type samplers are its portability, the ease with which

it can be repositioned without removing it from the well, and the

fact that it is relatively inexpensive.

Instruments to measure  temperature, specific conductance, or other

chemical or physical characteristics of the water in the well can

be placed in the space between the boots.  Experience has shown,' that

continuous measurement of specific conductance, in this way, is

very useful in determining the proper time to collect the water

samples.  It is desirable to pump from the well a volume of water

equal to at least 3 times the capacity of the discharge line and

isolated section before collecting samples for analysis, in order to

ensure the collection of representative samples."

The packer/pump shown in Figure 10 is less elaborate and more amenable

to fabrication without  the facilites of a machine shop.  Although

actual construction is  not described in the California Department of

Water Resources report, it seems that two rubber diaphr^fiis possibly

cut from tire inner tubes, were clamped, probably with stainless

steel hose clamps, to the exterior of the pump.  An  air  line  to  the

surface allows inflating or  deflating the packers.   If only  shallow

sampling depths are involved,  "home made  " diaphrams and valves  should

                                          /"»  r.™ =T"
                                      -r   £* ,v-  0
                                     ti 'A i—a U   u

take the inflation pressures  required,  greatly reducing fabrication

costs of the packer/pump.

 Single  WeLl'/Mu-rtiple^Samp Xing ^.Points	

 Perhaps the easiest way to construct  a well capable

 of  being sampled at set intervals within  the casing is to

 use 6-inch PVC casing,  slotted PVC screen, and glued-

 joint couplings. The screen sections of  set length can be

 separated by the appropriate lengths  of blank casing using

 only a  handsaw to cut the lengths and PVC cement to join

 them together.    This construction can be done rapidly and

 easily  by hand,  with simple tools and little skill.  A

 well in the hypothetical aquifer, with one-foot long screen

 sections separated  by four feet of casing would cost

 $3000 to $4700 to install.   Steel casing  and screen would

 be  considerably more expensive to assemble in this manner,

 and therefore casing perforation is necessary.  The cost

 of  casing perforation will depend on  how  familiar a driller

 is  with performing  this operation and whether or not the

 equipment is readily available.

 The pump/packer assembly necessary for sampling could be

 fabricated for $1000 to 2000 or more  depending on the pump

 used and how elaborate the packer system  is.  Portable

 generators cauble of supplying the power  necessary for the

 pump can be purchased for several hundred dollars.  Although

 these prices seem steep, they are  one-time cost and with

proper care  and  maintenance  the  pump/packer system should

last years.

                                         o  A  ^ T
                                         in, : -L 'j   :•:
                                                          - 34,

I. Excellent information on vertical

   distribution of-, contaminant.

2. Well diameter is large enough

   to use in a pumped withdrawal

   program, if necessary

3. Water samples representative

   of specific horizons within

   an aquifer can be collected

4. Sampling depths only

   limited by size of

   sampling pump

5. Rapid installation possible

 1". 'Expensive

 2. Proper well  construction

   and  sampling critical

   to successful application

"3. Complicated  sampling

   procedure involving a

   a great  deal of


                                                                                  - I
                              REFERENCES CITED
1.   Deportment of Water Resources, The Resources Agency of California.  1963.
     Annual Report on dispersion and persistence of synthetic detergents in ground water,
     San Bernardino and Riverside Counties.  A report to the  State Water Quality  Con-
     trol Board  Interagency Agreement No.  12-17.

2.   Cherry,  R.  N.  1965.  A portable sampler for collecting water samples from specific
     zones in uncased or screened wells.  U. S. Geological Survey, Professional  Paper
     525-C.  pp. C214-216.

3.   Hansen, E. A., and A. R. Harris.  1974. A ground water profile sampler. Worer
     Resources Research,  Vol. 10, No. 2. p. 375.

                                               J-- 35.
- Sampling During Drilling                      1~*>v  i- '^ ,„• • :'.  ."  _;


 A major disadvantage of the sampling techniques described

 above is that a constraint is placed on the data obtained

 from the ground water samples by the fixed or arbitrary

 point at which water samples are collected.  In other words,

 "blind" placement of wells can result in a false representation

 of contaminant distribution if it is not uniformly dispersed

 throughout the aquifer at the sampling point.  Contaminants

 are often stratified; underlain, overlain, or interfingering

 with uncontaminated ground water.  To define these

 relationships adequately, information on the vertical

 distribution of contaminant must be obtained prior to

 installation of the monitoring well.  This information can

 be obtained by formation water sampling during drilling.

 Several researchers have successfully obtained in-situ ground water

 samples during drilling using three basic techniques: 1) driving

 a casing (Fryberger, 1962), or well point  (Childs and others,

 1974) to the desired depth and bailing or pumping a water sample

 from that depth, repeating the process to completion depth or

 refusal; 2) drilling a mud rotary hole to the sampling depth,

 pulling the drilling string, setting and gravel packing a

 temporary well screen, and pumping a formation water sample.

 Yare, 1975); and 3)drilling a borehold to the desired horizon,

 setting a cone packer and riser pipe into the smaller hole and

                                                •- 35.
_ Sampling During Drilling                     '•'sf ** '± «''~\V .;   j


  A major disadvantage of the sampling techniques  described

  above is that a. constraint is placed on the data obtained

  from the ground water samples by the fixed or arbitrary

  point at which water samples are collected.  In  other words,

  "blind" placement of wells can result in a false representation

  of contaminant distribution if it is not uniformly dispersed

  throughout the aquifer at the sampling point.  Contaminants

  are often stratified; underlain, overlain, or interfingering

  with uncontaminated ground water.  To define these

  relationships adequately, information on the vertical

  distribution of contaminant must be obtained prior to

  installation of the monitoring well.  This information can

  be obtained by formation water sampling during drilling.

  Several researchers have successfully obtained in-situ ground water

  samples during drilling using three basic techniques: 1)  driving

  a casing (Fryberger, 1962), or well point (Childs  and others,

  1974)  to the desired depth and bailing or pumping  a water sample

  from that depth, repeating the process to completion depth or

  refusal; 2) drilling a mud rotary hole to the  sampling  depth,

  pulling the drilling string, setting and gravel  packing a

  temporary well screen, and pumping a formation water sample.

  Yare, 1975); and 3)drilling a borehold to the  desired  horizon,

  setting a cone packer and riser pipe into the  smaller hole and

                                             f- 36.
pumping a sample  (Harden, personal corr.T.unication, 1974).
If proper precautions are taken, formation water samples
collected using these techniques will be representative of
water quality at a known vertical interval of the aquifer.
The critical factor in successful application is developing
the temporary well to the point where all traces of drilling
fluid have disappeared from the pumped water before a sample
is collected.  Dilution of the sample by the drilling fluid
and contributions of chemical constituents by clay particles
in the mud will produce erroneous and erratic data, and little
information will be gained on the actual vertical distribution
of contaminant.
The main advantage of this type of sampling is that the top,
bottom, and internal stratification of the contaminated slug
can be defined with reasonable accuracy prior to setting a
permanent casing and screen.  With this information, the well
can be designed for the most advantageous sampling and/or
withdrawal of the contaminant at that point in the apfquifer.
Then, changes in the vertical distribution can be monitored
very closely.

Yare (1975) used a ground-water sampling during drilling
techniques in the course of investigating a hexavelent
chromium contamination problem.  A borehole was drilled with a
hydraulic rotary rig and drilling mud was made an  organic

                               UKAH"    ""•
base drilling fluid additive^-  ^In order to minimize the effect
of drilling fluid on the formation water.   A slotted  PVC  screen
attached to a riser pipe was lowered to the bottom of the borehole
 packed with fine gravel.  This, in essence, formed a well  in the
After the gravel had tine to settle through the drilling  mud
and around the screen,\well was pumped until no further traces
of mud could be detected.  By this time, an effective filter
cake had formed on top of the gravel pack, isolating  the  screen
from the fluid in the borehole and the filter cake between  the
gravel and the borehole wall broke down because of the pumping
gradient.  To insure that formation water was collected,  an
additional 100 gallons of water were pumped before sampling.  In
this formation, the effective radius of the well was  estimated at
2 feet.

The drilling and in-situ water sampling procedure which evolved
from this investigation consists of the following steps as  shown
diagraiamatically in Figure 5-13:
     1. drilling an eight-inch diameter borehole to  the
        sampling horizon;
     2. pulling the drill string and replacing the bit with
        a five-foot long, four-inch diameter wire-wound well
     3. lowering the screen and drill string to the  bottom of
        the hole and gravel-packing with number 2 gravel  to
        cover the screen;
     4. attaching a gasoline-powered centrifugal pump to the drill
        string and pumping until the drilling fluid  level

si»»x   u s\ y^A
                                                                      j     iJ
* _n_«**Tfl.
1 :
I (
fH.T£R .
''CAKE •
V-eLL •
• rec*.

                                    SiJ. W4T2R
   STEP I     STEP2     STEP3  STEPSA.&5  STEP 6
     Jn-situ ground-water sampling procedure.
                                                              VC'.' •

                                                             A  r
                                                            >-! 3*
        stabilizes in the hole and the discharge clears
        of drilling fluid   (in this case, a centrifugal
        pump could be used because static water levels ranged
        from 6 to 12 feet below ground surface);
     5. pumping at least 100 gallons of formation water before
        collecting the sample; and
     6. pulling and removing the screen, then lowering the
        bit and drill string, and drilling to the next sampling

Harden  (personal communication, 1974) described a sampling
during drilling technique useful in the deep holes in consolidated
sediment or rock.  In this method, the original hole drilled
is 6 3/4 inches in diameter.  When the hole penetrates about
15 feet to 30 feet into a sand from which a water sample is
desired, drilling is stopped  (step 1 in Figure 14) , and the
hole is reamed to a diameter of 9-7/8 inches down to a point
just above the zone selected for water sampling.  Then the
original 6-3/4 inch hole is washed out to its original depth,
(step  2 in Figure 14) and a string of pipe with packer and
screen is set in the hole,  as shown in step 3 of Figure 14.  The
pipe is usually 4 inches in diameter, and the packer is a
commercial rubber cone type, with typical dimensions of 6 by
9 by 14 inches.  Often a canvas "shirt tail" is wrapped by  the
packer to assist in sealing.  The packer is set on  the shoulder
between the 6-3/4 inch and  the 9-7/8 inch portion of  the
hole.  Below the packer a commercial 4-inch water well screen
10 to  20 feet long  is attached to the  4-inch pipe.  After
the packer is seated, the temporary well is developed by
airlift for several hours until the water becorr  s  clear.  After


J  ****'  '.
"*•*•• ~-'



          tar Sampling
From Test Hole.

                                                         P^ r^  A  T' -T
                                                         \^£ •  "  •'_ ._\  .''   j|
                                                                 '  '
this the air/line is removed from the 4-inch pipe, and a  	

small diameter turbine or hi-lifc pump is installed and the

temporary well is again pumped until i_ho water becomes clear, after

which the final samples are taken.

At the end of the pumping, the casing and screen are then pulled

from the hole, and drilling of the 6-3/4 inch hole is resumed

until a second water-bearing  zone is encountered from which a

water sample is desired, at which time the entire water-sampling

process is repeated.

Advantages                                 Disadvantages
1. The best technique currently

   available for defining vertical

   distribution of contaminant.

2. Completed well can be used  for

   water quality monitoring  and/or

   pumped withdrawal of contaminant.
                                            1. Considerable expense

                                              per well.

                                            2. Requires a knowledgeable

                                              drilling contractor

                                              and careful supervision

                                              of the  drilling and


Pore Water Extraction  from Core  Samples

pt» • ! - • 
                                                       .-T-V   „.
                                                       ; ,)  f\

sampling ourang                                        fc "
The most efficient technique for sampling the- hypothetical

aquifer described in 5.2.1 is to use .the technique described

by Yare (1975).  If this method is used, 10 samples can be

obtained at depths of 20, 30, 40, 50, 60, 70, 80, 90, 100

and 110 feet below ground surface and five of the most

contaminated intervals of the aquifer can be screened with

5-feet long, 4-inch plastic screens for a total cost of

$3000 to-?4700.  Additional sample points would cost $125 to

$200 each.  These screen segments could be sampled with a

packer/pump or by installing and isolating a deep pressure/

vacuum lysimeter in each screened interval.  If a packer/

pump is used, 60 inch casing is necessary and total cost

per installation would be in the range of $3300 to $5200.

Lysimeters could be placed for approximately $100 each.

                                     REFERENCES CITED

 1.  Childs, K.E. t  S.B. Upchurch, and B.  Etlis 1974.  Sampling of variable waste-migration patterns
     in ground water. Ground Water 12 (6): 369-376.

2.  Fryberger, J.S.  1972.  Rehabilitation of o brine-polluted aquifer.  U.S. Environmental Protection
     Agency.  EPA-R2-72-OU.

3.  Harden, R.W.,  Denver, Colorado, Personal Communication, 1974.

4.  Yare, B.S. 1975. The use of a specialized drilling and ground-water sampling technique for
     delineation  of hexavalent chromium contamination  in an unconfined aquifer. Southern, New
     Jersey Coastal  Plain.   Ground Water 13 (2):151-154.

                                                        l-rV  ? •?, :••„  y
                                                        H x^ $^\ a   y
and Gill and others, 1963).  A major problem with this technique,
is determining the amount of drilling fluid invasion into the
core during the process of driving the coring device and bringing
it to the surface; the greater the invasion, the less reliable
the water-quality data obtained.  Sand and gravels are more
readily invaded than finer grained sediments.

Luscynski  (1961) overcame this problem by putting fluorescein
dye (green color) in the drilling mud.  Any penetration of drilling
mud into a core sample would be shown by the green dye, and
the uninvaded core sections could be selected [r^o extraction.  Thus,
quantitative chemical analysis could be assured because dilution
of pore water by drilling fluids would not be a factor.  Unfortunately,
on completion of drilling, disposal of the bright green drilling
mud is a problem  (John Isbister, personal communication, 1975).
Normally, drilling mud is just dumped on the ground and is
eventually eroded away.  Because of its natural gray or brown color
it is not very obvious.  The bright green mud would be a definite
eyesore/"'and would probably have to be disposed of by burial at  the
site - no real solution.

Low permeability, porous, saturated sediments will retain most
or all of their interstitial water during core sampling.  Walker
and others  (1972) used this sediment characteristic  to  advantage
in tracing a bulb of nitrate-contaminated ground  water  at an
Illinois farm underlain by  loess  (Figure^ 15).  The  cores were air
dried,  leached with water,  and  the solution  was  analyzed  for
nitrate-nitrogen.   Because  of the nature of  the  sediment, Walker
and his co-investigators were able to trace the contaminant bu'b.  Under


                                                                        V   •'     ...     —

                                                                           i-«i .   L ^-A  ;• -\   /*   pra ^--
                                                                                    UK AS-  I
        different soil conditions, such as sand and gravel, this technique would be less applicable
         because little interstitial water is trapped in the core sample.  In this type of sediment
         the solution collected from leaching the air dried samples would primarily represent
         adsorbed constituents whose concentration would depend on the chemical activity of
         the soil.

*•»**   (pie filter press used; Luscynski (1961) describes in detail using a fi her press to extract
         pore water, is one of several types sold commercially for use in determining filtration
         properties of drilling muds.  The unit consists of a chcnbdr, a filtering medium, a
         graduated tube for catching and measuring the filtrate, and a pressure-source unit.  A
         cell, base cap. screen, rubber gaskets, and top cap make up the chamber.  The cell
         is 3£ iric nes high and has inside and outside diameters of 3 and 3£ inches,
         respectively.  The filtering medium is a sheet of filter paper which fits on the screen
         over the base cap; it* has a filtering area of about 7 square inches.  The filter paper used
         is specially hardened to withstand the pressure in the chamber.  A graduated cylinder is
         used to catch  the filtrate.

         Uninvaded cores consisting of loose material such as sand and gravel are transferred to
         the filter-press chamber by spatula or spoon. Usually it is not  practical  to remove much more
         than 25 to 50 percent of the uninvaded material from the core barrel by this method.
         Enough material is transferred to fill the  chamber about a quarter to half full.  It is then
         tamped lightly until an integrated unit is formed in the chamber and a film of water is

                                                                  r- «..
formed on the surface of the material and along the cylindrical wall. '

 Usually  less than 10 to 20 percent of a solid-brs^ilry-clay sample is invaded by the

 drilling  fluid.  Plugs of the uninvaded material I to 2 inches long are placed in the

 chamber to fill It about a quarter full.  Then they are molded and tamped into an

 integraded  unit.  Difficulty can be experienced in molding and tamping a  relatively

 dry solid clay-one  having a water conrent-of less than-15 to 20 percenfof  the dry

 weight of the clay.

The total time between the opening of the spliKspoon core barrel and the placing

 of the chamber In the frame is usually I  to 2 minutes for the' loose 'material and 2

 to 5 minutes for the tight ma'terlalV Tbei;e is thus,  very little opportunity  for


 After a sample is properly prepared for filtration, the chamber is fully assembled,

 placed in the frame, and made airtight J>y_the_T -screw (Figure' 1£).  The gas pressure

 is then applied.

 The pressure of the carbon dioxide gas in the chamber moves some of the interstitial

 water  through the filter screen and filter tube into the graduated cylinder.  Pressures

 of 5 to 30 psT suffice for the gravel, sand, and silt samples.  Pressures of about 100 psi are

 usually sufficient for silry and solid clay samples.  The carbon dioxide gas does not alter

 the chloride concentration of water forced from the material into the filtrate tube.

                    G»AOU*ltO CWMOtt
FICCII 1.—Filter prtM and cbaalitr a*»*mMjr.  Conrtnr or Eaciod DirUloo.

        Chloride determinations of the filtrate are made in the field by the standard titration

        method using silver nitrate solution.  Relatively large amounts of filtrate (25 to

        50 ml) are needed when fresh water is to be tested, and relatively small amounts

        (I to 10 ml) when salt water or diffused water is to be tested.

        Usually enough filtrate can be obtained from the uncontaminoted material of only

        one core if its  taken  in a diffused-water or salt-water zone.  However,  more than

        one core may be necessary to obtain the required amount of filtrate if the core is

        taken in a fresh-water zone; this is particularly.true for solid-clay samples, which

       XJefd only small amounts of interstitial water."

        An alternative to the  mud filter-press is to fabricate a core sample squeezer which

        utilizes a hydraulic ram, as described by Manheim (1965):

1st      "The squeezer utilizes a commercially available cylinder and ram (made by the Carver

        Co.,  Summit,  N. J.) to which a machined base with a filtering element and fluid

        outlet is fitted.  Construction  details are shown in Figure 5-17. The filter unit

        consists of a  stainless  steel screen and a perforated steel plate contained in a circular

        recess in the steel filter holder.  Alternatively, a porous (sintered) metal plate may be

        used to replace both screen and perforated plate.  The top surface of the filter should be

        flush with  the other rim of the holder so that it may support one or more  paper filter

        disks.  Finegrained,  hardened laboratory filters give a visually clear effluent, but

        membrane  or microfilters may be used to assure maximum freedom from suspended matter.

        The lower part of the  filtering assembly, fitted with a rubber washer, protrudes into a

          recess in the steel base;  when pressure is applied the gasket is squeered against  the

          cylinder  and prevents leakage of water around the filter unit. The space in the  recess


                                                                     ft   ?
y M   #$  £.
J IXMl     S
                             (Alter p»t>*r support) (i>

                               inl*si st*«i »i/*-jcr
                               dijk. Jj-in H-ck (3)
         . r    i  I        *— Ernutnt ^a^iaA* r*»m«o
         y |          |     I  to fit no** of Cyrix** U I)
                                             Syf r>z* CD
',±lcpn1i"r—Drawing  show-ins  components of  bydrsulic
   squwsrer.  Ail dimensions in incaes.  (Biie ii about
   2>i iachea in height.)
        U  i.  \  7


                                                                   !' ""^  ''"^  f\   r*
                                                                   •'  -1  i  ''  /' \
ond the diameter of the outflow boring are kept small so that little fluid can collect in

the squeezer itself. All metal parts in the filter base are made of Iron and Steel

Institute No. 303 stainless steel.  Rubber and teflon disks just below the piston prevent

loss of fluid upward when pressure is applied.  The rubber,teflon, and filter-paper disks

ore punched out with an arbor punch and can be made as needed.

The present design permits insertion of a disposable syringe  (preferable1/ plastic) directly

into the base of the squeezer to receive fluid.  The narrow  effluent hole is reamed out

to permit fitting of the standard 'Luer1 taper of the syringe nose.

A larger squeezer has  also been constructed  using a 2£ - inch Carver cylinder and

piston.  The design is  similar to that shown in Figure 5-16,  except that the  filter plate is

increased in thickness to give greater strength.  The effluent line remains small.  Because

the cross-sectional area of the cylinder bore of the small squeezer is about 0.88

inch, a 10-ton laboratory press exerting its maximum  load of 20,000 pounds will apply

a pressure of about 22,000 pounds per square inch to  the  sediment.  However, a

20,000  Ib load will apply only about 5,000  psi in the large unit. The  large squeezer

should therefore be used with a higher capacity press when  more compact sediments are to

be squeezed.

In sequence, the steps in squeezing a sample are as follows: The filter holder with  its

gasket Is placed in the recess of the filter base.  The screen, perforated plate (or porous

disk) ond 2  or 3 filter-paper disks are positioned.  The cylinder is seated over the filter

                                                                       Q XI  fy   f\  iT51 *••

unit so that it rests firmly on the base.  Sediment is then quickly transferred into the

cylinder through the top, followed by the teflon and rubber disks.  The teflon and rubber

disks can be placed above the sample in either order to obtain a leak-free pressure transfer,

but placing the teflon disk below the rubber disk gives a cleaner seal than the reverse

order shown in Figure 5-17.  The piston is depressed as far as it will go into the  cylinder,

and  the whole unit put in the press for squeezing.  Pressure  is applied gradually at first,

and  when the first drop of interstitial fluid is seen the syringe is seared in its hole in the

base (effluent passage in Figure 5-1?.) The squeezed-out liquid moves the plunger of the

syringe back as the liquid is expelled, and there is minimum opportunity for evaporation.

When the desired amount of liquid has been obtained,  the syringe is removed and capped.

  After extraction of the liquid the parts of the apparatus are rinsed with distilled

water and (except for rubber parts) with acetone. The acetone helps dry the unit

quickly in preparation for the next sample.  The  squeezing and washing operations

together can be completed in 5 to 10 minutes."

Pore Wate'rxExfracti'O'hN from core samples.
                ~                    -*s
The main expenditure  in this type of  sampling is the
filter press.  The current price of  this piece of equipment
can be obtained  from  Baroid Division, NL Industries,
Houston, Texas.  Current charges for  cores obtained by wire-
line, 2-inch diameter split barrel samplers are/30 to^SO
        per core.  A  section of core  can be taken from the
sampler, molded  into  the filter press, the fluid extracted
and analyzed for chloride concentration, and measured for
specific conductance  in a half hour  or less.  Therefore,
cost will" depend on  the investigators' salary or hourly
billing rate.


1. Inexpensive
2. Pore water extract amenable to
   field chemical analysis.
3. Excellent vertical sampling if
   mud invasion into core sample is
   monitored, quantitative analytical
4. Samples can be obtained from almost
   any depth if wire line coring apparatus
   is used.
5. Qualitative use of pore water extract
   allows presence/absence determination.
6. Can be used with consolidated rock
   as well as unconsolidated sediment
1. Quantitative analysis
   require careful control
   during sample collect:.
2. Interstitial water can
   drain from unconsolidated
   sand and gravel reducing
   volume of water sample
   that can be obtained.
3. Disposal of dyed drilling
   mud is a problem.
4. Core recovery in coarse
   sand and gravel can be
   difficult and time
5. Small sample volume
   available for chemical

                                     REFERENCES CITED

 1.  Gill,  H.E ., and others 1963.  Evaluation of geologic and hydrologic data From the test drilling
     program at Island Beach State Park, New Jersey.  New Jersey Division of Water Policy and
     Supply.  Water Resources Circular 12.
2.  Lusczynski, N.J. 1961.  Filter-press method of extracting v/ater samples for chloride analysis.
     U.S. Geological Survey Water Supply Paper 1544-A.

3.  Manheim, F.T. 1966. A hydraulic squeezer for obtaining interstitial water from consolidated
     and unconsolidated sediment. U.S. Geological Survey Professional Paper 550-C, p. C256-

4.  Swarzenski, W.V. 1959.  Determination of chloride in water from core samples.  American
     Association of Petroleum Geologists Bulletin 43 (8): 1995-1998.

5.  Walker, W.H., T.R. Peck, and W.D. Lembke 1972. Farm ground water nitrate pollution -
     A case study. American Society of Civil Engineers Annual and National Environmental
     Engineering Meeting October 16-22,  1972. Meeting Preprint  1842.


                                                    O w *

Field Inspection --  £*f*' •
    field inspection is an extremely valuable tool in

evaluating landfill sites.  Although an inspection in the hands

of a trained observer would produce more data, even the most

unskilled person can identify the presence of leachate in
springs, seeps, and streams by its color and odor.  Frequently,

vegetation that has been exposed to leachate can be found in a

dead or dying state.  The appearance, surface configuration, and

drainage away from a landfill gives insight into the amount of

infiltration of precipitation that might be taking place.  A

study of surface drainage, topography, and nearby wells enables

the inspector to make an estimate of ground-water  (and leachate)

movement.  Field observations increase in value when combined with

geohydrologic information and other pertinent basic data contained

in published reports and agency files.

In the following pages, it becomes evident that many of the

techniques discussed can be combined with the field inspection to

provide even more information.  The degree of success is strictly

within the ability of the inspector to interpret the situation

and the amount of time available for the study.

In practice, the inspector should have in his possession at

least a sketch map of the landfill site; a detailed map or

areal photograph would be better.  By walking around the pfctJL-iuiuUiJL

of—the landfill and infrrr 1 he surrounding acreage^and recording
what is found, the overall picture is recorded to- the map, where

it is more easily interpreted.


1. Can be carried out quickly
   and inexpensively.
2. Helps place the overall
   problem in perspective.
3. Establishes the extent of
   additional investigations
   which may be required.
4. When combined with a
   literature and available data
   survey, can be used by an
   experienced hydrologist to
   roughly establish the overall
5. Provides an opportunity
   for first hand discussion
   with landfill operator
   and other personnel.
                                                 .T- 48.
 1. Untrained inspector
    may overlook subtle
    but valuable data.
 2. Findings  are not always
    conclusive in detecting
    contaminated by leachate.
3. Provides no indication of
   changes in condition with
4. Provides little hard data.
5.  Untrained  inspector may
   be misled  by visually
   impressive Jyg  «*u"t"
   environmentally insignificant
   features.  This could occur
   in either  a  positive or
   negative direction.

                                              - 49.
The cost of a field inspection of a landfill  can be quite  variable,

depending on the size of the operation  and the complexity  of  the

surrounding terraine.  In this and each of the following sections,

an estimate of the cost of carrying out the task described is given.

This cost is based on an estimated daily rate for  the personnel

required to perform the task, an estimated length  of  time  for the

tasks based on an average situation and other related expenses such as

lab fees and living expenses.  In all cases,  the estimated cost should

be considered accurate only to about plus or minus fifty percent.

For a-field inspection of an average (50 acre) landfill, ,ohe  man

at /'the hydrogeologist or engineer level would be  required for 2X^:0

3 "days at $200. per day. '--The estimated total cost is $600.

Hughes, G.M., R.A. Landon, and R.N. Farvolden.  1971.  Hydrogeology

of solid waste disposal sites in Northeastern Illinois.  U.S.

Environmental Protection Agency publication No SW-12d.  154 P.


Small springs of discolored, malodorous leachate which are frequently

found along the lower edges of many landfills are referred to as

seeps.  These may be the only visible indication of landfill  leachate

and, therefore, receive more than their share of attention.   In

fact, however, they represent only a very small fraction of  the

total leachate being generated by the landfill.  The few gallons

per minute visible in seeps are insignificant when compared  with

the hundreds and perhaps thousands of gallons of leachate  seeping down

unseen to the water table.  However, as they  are indicators  of

leachate, they deserve  some consideration.

    Seeps may represent the intersection of the water table and
    the land surface, or they may be discharge of  a small perched
    water body within the landfill.  Sometimes a distinction
    between these two situations can be made by inspection.
    For example, if the land surrounding the landfill is dry,
    a seep discharging along the face of the refuse is not
    likely to represent the water table.  A further and more
    definite way of distinguishing between the two situations  is
    by installing a well point nearby and establishing the true
    water table position near the seep.  This well point has the
    added advantage of permitting a sample of ground water to  be
    collected and tested for leachate.

    One value of seeps is in the collection of concentrated
    leachate samples.  However, it should be kept  in mind that it
    is possible that the seep may not be representative of the
    large volume of leachate generated in that particular landfill.
    In fact, the chemical characteristics of any leachate sample,
    regardless of its source, should"be considered representative
    of the total volume of leachate.  Typically, landfill leachate
    has proven to be highly variable, both from location to  location
    in a landfill, as well as from time to time at the same  point.
^   A second value of seeps is that substantial changes in seep
    locations or flow rates, or the sudden appearance of new ones,
    indicates a changing flow system within the landfill. The exact
    nature and causes of the change, however, must be investigated
    by other means.

1. Where present, definite
   indication of leachate
2. Convenient point of
   collection for leachate
3. Changes  in flow rates
   or locations of seeps
   is indicative of interval
   landfill changes.
                                              £•- 51.
 1. May not indicate
    presence of
    contaminated ground
2.  Chemical quality not
   necessarily repre-
   sentative of bulk of
   leachate in landfill.

     Examination of seeps would typically be included as a part
     of the field inspection and would not represent  an  additional
5- 7  Vegetation Stress

     A significant impact produced by a landfill on the  surrounding
     area is stress and possible destruction of vegetation.  Stressed
     species may include agricultural crops, stands of trees, and
     marsh or meadow vegetation.

     In  marsh  environments subject to leachate  discharge,  the
     vegetation is an excellent eja^eetnnenESI monitor to assess
     ecological stress on the total system.   In addition to being
     stationary and sensitive,  marsh vegltation can be studied for
     signs  of  stress using aerial remote  sensing techniques as
    well  as directly by the botanist in  the field.   Crops and
    trees  growing in areas of  deeper water  table than is
    associated with the marsh  environment are  more likely to be
    stressed  by landfill generated gasses than by leachate.  Various
    types  of  agricultural crops as well  as  fruit orchards, have been
    destroyed by  migrating gashes  generated within a nearby landfill.
    Preliminary  stresses placed on these species, prior to their
    actual destruction,  are often  detectable by the  botanist and
    by aerial  remote  sensing.

    While  identifying  the precise  cause  and mechanisms  of stress
    may be prohibitively costly, it may  be  possible  to  relate
    the stress to a general cause  which  may in  turn  be  related


to the presence of the landfill.  Mapping the extent of

stressed vegetation is an excellent indication of the extent of

the total impact of a landfill on its surrounding environment.

Also, early detection of stress sometimes permits the

opportunity to institute corrective measures in time to

prevent irreparable damage.
A p-
A cursory look at vegltation stress would be included in

the field inspection taks and would not represent an additional

                             '     c
expense.  A detailed survey of vegetation stress, including an

assessment of probable cause would require 1 to 2 days of field

work by a botanist plus some laboratory work.  The estimated

cost of such a survey is $1,000.

If vegetation stress is to be used for monitoring, or if

specific recommendations regarding the saving or replacement

of stressed species, the required program might cost between

$10,000 and?100,000, depending on the extent, complexity and

goals of the programs.

Geraghty & Miller, Inc.  1973. Environmental Feasibility,

Proposed Silver Sands StQte Park, Milford, Conn. Project

Bi-T-55A.  Report to State of Conn., Public Works Dept.  Dept.

of Environmental Protection.

                                                   r- ss.

1. When found, good indicator

   of contamination by

   leachate or gas.

2. Mapping extent of stressed

   vegetation gives good

   indication of the limits

   and source of contamination.

3. Stressed vegetation can be

   mapped remotely i.e. aerial

   photographic methods, thus

   allowing wide coverage in a

   short period of time.

4. Stress changes provide a

   good monitoring device.  This

   effect may be enhanced by

   actually planting selected

   species in by areas and watching

   the results.

1. Evidence of stressed

   vegetation, especially

   in early stages not

   always evident except

   to trained botanist.

2. Some species of plants

   are more resistant to

   to effects of

   contamination than

   others.  This may be

   an advantage in multi-

   special  area as an

   indicator of increasing,

   or decreasing contamin-

   ation  or by producing  a

   clue  as  to stress


 3. Stress may be  caused by

   many  factors,  some

   unrelated to  the  presence

   of  the landfill.

    Determination of  the

    responsible factor or

    factors is usually

    extremely difficult even

      ^- the botonist.

                       r- 56.
Disadvantages, continued

4. Stress will not occur unless

   physical or chemical change

   occurs at the surface or within

       Vide is
   the vaeir zone.  Therefore,

   provides no indication of sub-

   surface problems.

                                                          .r- 57.


£•>' "Specific Conductance and Temperature Prober.
                                                              AfT* "T»
                                                              r  8
     Vr;o physical characteristics of ground water  v/hich can bo

readily measured in the field are specific conductance and

temperature.  Since landfill leachate generally has substantially

higher temperature and specific conductance than natural fresh

ground water, the presence of leachate often can be determined

using these two characteristics.

    ^  Typically, in situ measurements of ground-water

characteristics would be made by lowering a remote-sensing probe

into a well and recording the results from instrumentation

on the surface.  In areas of high water table, hovrever, the

measurements can be nade without installing a well.  The method

involves 'the use of a self-contained conductance-temperature probe.

Construction details of such a device are shown in Figure j-~.je_

        The probe can be pushed directly into the ground where

sediments are soft, or inserted into a small-diameter hand

augured hole where the ground is harder.  When the probe is below

the water table, the outside tube, which has protected the

perforations from clogging during insertion, is retracted, allowing

the ground water to flow into the tube.  Specific conductance and

temperature of the ground water can then be recorded.  After

removal from the ground the perforated end of the probe is washed

in clean water.

        Under good conditions, a two man crew can carry all

necessary equipment into the field and make a series of probe

measurements over a typical landfill site in 2 or 3 days.  In addition,

measurements can be made easily in swampy -areas not accessa'olo  to

drilling rigs or resistivy survey crews.

t- iQ
                 ALUMINUM BOX  FOR
                 MOUNTING METERS
                                           SPECIFIC  CONDUCTANCE
                                      PROBE WIRES

                                    I INCH INSIDE DIAMETER
                                    ALUM4NVM TUBING
                                        INCH  INSIDE  DIAMETER
                                        ALUMINUM TUBINfr  USED TO
                                        COVER PERFORATED SECTION
                                               CUTAWAY VIEW OF
                                               PERFORATED SECTION  *•*
                                               SHOWING REMOTE P'ROBES

                               "r^ r5^  A  ["^i «TS»

-. 58.
    The cost of a ground-water conductance  and temperature survey

    using a probe such as the  one  described above/ and assuming


    the surface conditions were such  that this type of survey

    would be practical,  would  be about  $900.  This estimate  is

    based on the cost  of a hydrogeologist or equivalent  and  a

    helper ($60.  per day) for  3 days.   The  survey may require a

    day or two more or less depending on the size of the site to

    be investigated and its accessibility.

    Geraghty & Miller, Inc. 1973.  Environmental Feasibility,

    Proposed Silver Sands State Park, Milford, Conn.

    Bi-T-55A.   Report  to State of  Conn., Public Works Dept.

    Dept.  of Environmental Protection.

3. i)  Electrical Earth Resistivity

    An electrical earth resistivity survey  can be used to define

    subsurface geology and the extent of leachate contamination

    of ground water.   The results  of  a  resistivity survey can

    be used with a minimal amount  of  direct sampling as  a basis

    for decisions on the necessity of remedial action, or it can

    be used as a preliminary investigation  from which a  detailed

    drilling and sampling program  is  designed.  Since resistivity

    is an indirect method, however, and is  subject to possible  error

    in interpretation, it would be unwise to base final  conclusions

    on resistivity results alone.

The earth resistivity method depends upon the conduction

of electric current through the subsurface materials.

The magnitude and distribution of the current flow is  a

function of the effective resistivity (or its reciprocal,

conductivity) of the subsurface material.  The effective

resistivity of saturated materials is dependent upon

moisture in interstices and pores because the vast majority

of the constituent minerals are poor-conductors.  The pore

spaces that contain water also contain some dissolved salts,

and it is these ionic  solutions that allow the passage of

current  from  the surface into the underlying material.  It

has been found that  the resistivity of materials  such as

moist clays and silts  is low; but,  in dry, loose  soils, sand

and gravel, or sand  and gravel saturated with high-quality

water, the  resistivity is high.  The electrical resistivity

of a material is  a function  of the  actual  resistance of the

material,  and the  length of  the  current  flow.   Because  earth

materials  are not  homogeneous,  the  measured  resistivity is

actually termed  apparent  resistivity and is  defined as  the

weighted average  of the actual  resistivities of the individual

subsurface materials or strata within the depth of penetration

of  the  resistivity measurement.

To  measure earth resistivity, a known current is introduced

 into the earth through two current electrodes and the

 resulting potential drop is measured between a second pair of

 potential electrodes.  If the electrodes are arranged in a

 straight line and the separations are increased  at constant /W. «><•«>•

                                            r- c.n     ll\ *T>  A  ff» «=•
                                          ,  r-so.    r  a EJ  M  a   ^
                                                    £*/ S^M 3   8

it is possible to make inferences about the  relations  of

variations in apparent resistivity,  depth of penetration,  and

electrode spacing.  Various procedures have  been  developed to

interpret resistivity data.   The procedures  are grouped into

two basic types:   Theoretical and empirical.  In  using the

theoretical method,  the field data are plotted, describing a

curve which is compared with sets of master  curves developed

for numbers of resistivity layers with definite ratios of res-

istivity and thickness.  With this method, the lvalues of

resistivity for each geologic unit as well as thicknesses and

depths can be determined.  An example of an empirical

interpretation is shown on Figure s~-i?. With this method the apparent

resistivity and accumulated apparent resistivity  values are plotted.

The first curve indicates the type of material and the second curve

shows the .depth of the interface between layers.

Use of the resistivity method to define a Leachate Plume relies

as the fact that the conductivity of the ground water is inversely

proportional to the resistivity measured in a  section of earth

containing that ground water.  Since the conductivity of landfill

leachate is generally much higher than that of natural  fresh ground

water, a sharp decrease in apparent resistivity will occur where

leachate is included in the measured section.  Thus, by running series

of resistivity measurements at the appropriate depth on a grid over  a

landfill site, it is possible to define the  lateral extent of  the

leachate plume by contouring the resistivity  values obtained.  The

results of a resistivity survey  at a  landfill site are  shown  on

Figure _~- 2 0.

  aoo    oo
 |600 f 60
i     f

H     4

1     I
M.400 R 40
                        20           40           60            80

                                 DEPTH, IN FEET BELOW LAND SURFACE
                                                                                                + 40
                                                                                                      WELL LOG



                                                                                 •' -i *""/•
     .-' ./-^• I(    Site
                                                           - -ft'.


1. Can define subsurface

   geology and contaminated

   water bodies much  faster

   and cheaper than drilling.

2. Can be used to greatly

   reduce the number  of

   sampling wells required.

3. Surveys can be duplicated

   periodically to provide

   monitoring data.
1.  Indirect method-

   requires some

   substantiation by


2.  Experienced operator

   is  usually necessary

   to  obtain useful data.

3.  Many natural and man

   made field conditions

   preclude resistivity


4.  Data interpretation

   in  complex situation

   is  often questionable.

                                           jT- 62,
DIT^  A  ;>»
R A fi-
     The  cost of a resistivity survey would be essentially the same

    .as  for  a seismic survey  ($1,800. for a typical landfill site)

     and the same qualifications would apoly.

     Cartwright, K., and M.R. McComas.   1968.  Geophysical surveys

     in  the  vicinity of sanitary landfills.  Ground Water.   6  (5):23.

     Stellar,  R.L.  and  P. Roux.  1975.   Earth  resistivity surveys -

     a method  for  defining ground-water  contamination.   Ground

     Water.   13 (2):  145-150.

     Parasnis,  D.S.   1962.  Principals of Applied Geophysics.   John

     Wiley ft Sons,  New York.

     Geraghty & Miller, Inc.   1973.  Environmental Feasibility,

     Proposed Silver Sands State Park, Milford, Conn. Porject Bi-T-55A.

     Report to State of Conn., Public Works Dept. Dept. of

     Environmental Protection.

£3* Seismic Surveys

     Seismic surveys are used to determine the depth to bedrock  and

     the thickness of  the materials overlying the bedrock.  The

     refraction method of seismic  exploration utilizes  the  principle

     that energy waves can be propagated through earth  materials.

     The velocity of propagation  is governed  by  the  elastic

     properties of the earth materials  through which the waves are

      travelling.   These elastic waves can be  timed from their

      initiation  to a known distance from the  energy  source to

      determine their  velocity.  With known velocities and distances,

      depths to the various geologic interfaces can be calculated.

                                                          - 63.
The seismic reflection method of geophysical surveying may also

be used.  This system, in which the energy wave is reflected from

the different geologic horizons, can usually penetrate greater

depths than the refraction method.

Where well data are  available, correlations are made between

the results of the seismic survey and existing information

for more refined interpretations.  Where well information is

not available, evaluation of seismic data is based on the

interpretation of the geologic environment and experience in


The techniques of operation in the field depend on the various

applications of the  seismic refraction method.  In order to

determine depths and seismic velocities of various materials,

the reverse profile  method is used.  A reverse ptofile is one

in which the most distant energy source and the geophone,

which is the receiving unit, are interchanged after recording a

profile and a second profile is then recorded.  The energy source

is a hammer blow on  a steel plate or an explosive charge.  With a

single geophone seismic  unit, a- seismic profile is conducted by

implanting the geophone  firmly in the ground and moving the impact

point away from the  geophone at measured distances.  For a multi-

geophone unit, the geophones are placed at selected distance

intervals along a line,  and a single energy source, usually an

explosive device, is activated.  By observing the energy arrivals

for different separations between the impact point and the receiver

or receivers, a travel-time curve can be constructed illustrating

the energy travel- time with distance.

                                        r-64.  no  A  s»
A seismic survey requires a trained operator and an experienced
geophysicist to interpret the data.  The complexity of the data
reduction process, generally requires the use of a computer.
For these reasons, seismic surveys should be contracted to a
firm providing geophysical services.


1. Can. provide subsurface
   geologic information much :
   faster and cheaper  than
2. Can be used to  extend
   geologic data over  broad
   areas on a limited  budget.
3. Can be used in  certain areas
   where access for a  drilling
   rig would be difficult.
                                                        ~- 65.
                                                                 A  P™ "ss»
                                                               /4I- I
r. Being an indirect method,
 "  it requires more direct
 ' substantiation such as
2. In complex geologic
   formations, interpretation is
   difficult and substantial
   errors may occur.
3. Requires a trained person
   and computer access to reduce
   and interpret data.
4. Subject to noise interference
   in many field situations.

                                                            DO ,A
                                                            «* & -\
The estimated cost of a seismic survey for a typical landfill site

is $1,800, based on two days of field work for the seismic crew

and data reduction and interpretation by a geophysist.   This

would be a typical survey to define subsurface geology in the area

immediately surrounding a 50 acre landfill.  For surveys encompassing

substantially larger areas, the-cost would increase proportionally.

If access were difficult, if areas had to be cleared of bush for

example, the cost of this ta^s* would have to be added to the

cost of the actual survey.

Parasnis, D.S.  1962.  Principals of Applied Geophysics.  John

Wiley & Sons, New York.

Anon.  1972.  Ground Water and Wells. Pub. by Johnson Division,

Universal Oil Products Co., St. Paul, Minn. 440 P.

Geraghty & Miller, Inc.  1973.  Environmental Feasibility,

Proposed Silver Sands State Park, Milford, Conn. P,€|i/ject

Bi-T-55A.  Report to State of Conn., Public Works Dept.  Dept.


of Environmental Protection.


Surface water bodies such as ponds  or streams which  are  in  close

proximity to landfills often have an orange color and  an oily

film on their surface.  These obviously polluted water bodies  are

discharge points for contaminated ground  water  which originate

within the landfill.  Location of these discharge points  on a

topographic map of the landfill  site will often help provide

a reasonable preliminary  picture of the ground-water flow patterns.

rr**s iT^j  A
 Where  surface water bodies are large  or  rapidly flowing,/

 dilution  of leachate as it discharges is often sufficient

 to prevent detection by visual inspection.   In such cases,

. water  samples would be taken and analyzed to establish the

 presence  of typical leachate constituents.


 Prior  to  the collection of surface water samples, a specific

               £• W                 *
 conductance, -Bk, Eh or dissolved oxygen  survey, using portable

 instruments to make in site measurements, should be conducted.

 Such a survey can provide much useful information itself,

 or at  least indicate the locations from which  surface water

 samples should be taken.  The importance of an analysis

 of surface water quality at a landfill site is twofold;  first,

 determination of leachage discharge areas is important in

 establishing an overall hydrologic picture, and second,

 surface water quality degredation is an important component  of

 overall environmental degredation and should be carefully

 examined.  Also in a full investigation of surface  water bodies

flear  a  landfill, the native biota should be studied  for  leachate


                                                  00 .


1. Useful in locating leachate
   discharge points.
2. Can be a quick and inexpensive
   means of estimating
   environmental impact of landfill.
1. Detailed analysis of water
   samples can be fairly
2. Surface water may be subject
   to contamination from other
   sources not defined.
3. Dilution may be too great
   to provide useful

                                                  ~~ 69,
                                                          IA FT
The estimated cost of a surface water quality  survey as

described above, assuming significantly complex surface water

bodies exist, is $300.  -This is based on 1 to  2 days work

for a field hydrologist or technician at a daily rate of $150.

It is assumed that this program would be part  of a more

extensive investigation and that analysis of the results

of the surface water quality survey would be covered under a

more general data analysis phase.

Geraghty & Miller, Inc.  1973.  Environmental Feasibility,

Proposed Silver Sands State Park, Milford, Conn. Project Bi-T-55A.

Report to State of Conn., Public Works Dept.  Dept. of

Environmental Protection.

Landfill Gas Measurement - Landfill gasses, particularly  carbon

dioxide  (CO  ) and methane  (CH.), can present serious  problems  at
           2                 ^

landfill sites and their concentrations and movement  should

always be investigated.  Gas related problems include explosion

vegetation destruction,  and ground-water pollution.   Since

generation of carbon  dioxide, methane  and other gases is  the

natural  result of organic  decomposition, all landfills will

produce  these gases.  The  questions to be resolved are the

direction, distance,  and rate of movement of the gases prior to

discharge to the  atmosphere.  The  answers to these questions

will  establish  the  location and design of gas venting systems

should  they  be  necessary.

                                                                    A  F* •".'
 At  least  two methods of gas measurement are available; collection of
 a gas  sample for  laboratory analysis and in-situ measurement of the
 explosive potential of confined gas.  Sample collection or explosive
 potential measurement of gasses in the subsurface sediment is by
 specially designed gas probes, an  example of which is shown in Figurer-zt.
 A gas  sampling bottle or measuring instrument is attached to the upper
 end of the probe  and evacuated.  Gas from beneath the landfill then flows
 through the probe to be collected or measured.  Multidepth probes may be
 installed as shown in Figure f-aa. In addition to landfill installations,
 probes should be  installed in natural sediments around the landfill to
 establish the lateral migration patterns of the gasses^  All enclosed
 spaces near the landfill, such as basements, manholes, etc, should be
 tested for accumulation of explosive gas.  Examples of a measuring device
 and sampling bottle are shown in Figure S - if.

 The potential for methane recovery at a major landfill should be
 explored  (Ref_7)  The potential revenue from this resource may offset
 the cost  of the investigation and pollution abatement and monitoring

Problems  associated with gas migration and buildup at and near a
 landfill  site may be alleviated by the installation of gas vents and/or
gas barriers.  Typical gas vents employed in landfills are shown in
FigureS-l>  Gas barriers would either be put in place prior to landfilling
where  the  landfill will abutta natural permeable face such as the
vertical wall of  a gravel pit, or, in some cases, clay slurry trench may
be constructed after the landfill is completed if conditions indicated a
shallow barrier would be effective.

' robe.
                                                           i*l f A*il 1 •  T
                                                    PLUG END OF PROBE
                                              CEMENT OR CLAY PLUS
                                             PERFORATIONS  I* MW.
                                             (CAN USE HAND DRILL, KNIFE POINT,
                                             OR OTHER SHARP INSTRUMENT TO
                                             PERFORATE TUBE END)
                                    LEAD  WEIGHT TAPED OR TIED
                                    TO BOTTOM OF PROBE

        CEMEWT OF»
        CLAY PL
                                    GAS SAMPLING TUBES
                                        LAND SURFACE
                                      NATURAL GROUND
                                        OR REFUSE
                                    GAS PROBE

      S -

t.-uvv^.'/""'  ft-.*/'
                   MEASUREMENT  PROCEDURE


         CHECK VALVE
                                               RUBBER  BULB
                                  COMBUSTABLE  GAS
                                              UBBER HOSE

                                               RUBBER BULB
                                                             -v- /

                                         e, ,.*

                                                                  :•••'••••;:••:•••:••'••• ••••••-• -"-••.•••.•.' •••••••••• -•^•.--

                                                               "^:^-^^-:^v:^y^::-v. **#:-:.::'W.:'.S:..y
                              BOTTOM  SEAL
                                                        ORIGINAL  GROUND
                  8  DJAWETER HOUE


1. Detection of methane accumulation

   can prevent explosion hazard to

   personnel and property.

2. Establishes the need for special

   gas ventearing system.
                                                            •*V  Iv33

1. Proper analysis

   of gas measurement

   data is complex

   and would require

   experienced personnel.
3. Provides a clue as to possible

   cause of vegetation stress.

                                                          DP  ACT
                                                          I •£  f  \  • •—*  u
                                                          ii 'V  /^^A  -<   n
                                                          u  *>.  *  -A  a   (I
   The cost of a landfill gas survey would be about $900-, including
   2 or 3 days of field measurements by a hydrologist,  engineer or
   equivalent and laboratory analysis of several samples.  Detailed
   analysis of the results of the survey and remedial recommendations
   are not included and the complexity of such a task and thus its
   cost would depend on the results of the initial  survey.

   Merz,  R.C.   Determination of the Quantity and Quality of Gases
   Produced During Refuse Decomposition.   University of Southern
   California,  Los Angeles.   Engineering Center Quarterly Reports.
   U.S.C.E.  Report 83-3,  Sept.  30,  1962;  86-6,  July 30,  1963;
   87-7;  Sept.  30,  1963;  89-8,  Dec.  31,  1963.

   Merz,  R.C.  and R.  Stone.   Gas  Production  in  a Sanitary Landfill.
   Public Works,   95:84 February,  1964.

   Engineering-Science, Inc.   In-situ investigation of  movements of
   gases  produced from  decomposing  refuse.   Final report prepared for
   California State Water Quality Control Board.  Pub.  No.  35,
   April,  1967.

"•  Aerial  Photography

   Aerial  photography has  several important  uses in  landfill studies.
   In its  simplest form,  an aerial photograph, whether black and white
   or color, will show  the landfill  and drainage away from  it.   For
   large areas, remote  sensing of vegetation stress  using aerial
   photography map be a justifiable  undertaking.  Advances  stress may
   be visible on color  photography and less  advances stress  may  be
   ennanced and distinguished using  infrared photography.   Another

                                                          P  A FT
                                                          d ^ <;-*^ sr 9
method which has been  used in landfill investigations is

multispectral aerial photographs.

Multispectral photography uses special equipment to determine

subtle differences  in  light  reflected at different wave lengths

for stressed and unstressed  species.  Photographic filters that

will enhance this difference are used, and several images of the

same area are made  at  the same time using a multi-lens camera ana

the selected filters.   Differences between stressed and unstressed

vegetation are  further enhanced by projecting the images through

different color filters and  superimposing on a projector screen.

In addition to  vegetation stress, aerial photography is frequently

useful in constructing contour and location maps of landfill sites,

Accurate contour maps  of the landfill surface are used  in

determining hydrologic characteristics of the landfill.  Stereo

color photography  is used to construct and up-date topographic

maps of the active  landfill  sites as the  surface changes.  Bench

marks, wells, and  other sampling points.

                                                       -- 74.
                                                              3  A  C
                                                           ~r t «

1. Frequently can detect stressed

   vegetation evidence of


2. Can be used to prepare contour

   maps relatively inexpensively.

   Also provides certain geologic


3. Much less costly than a

   detailed ground survey of

   vegetation stress.

4. Yearly photos can provide

   unbiased and indesputable

   evidence of surface changes;

   e.g. landfill configuration,

   vegetation condition, surface

   water body location.

5. Can be used to precisely locate

   on a map key points on the

   landfill site such as wells or

   ^eismic Stations.

6. Enables persons to quickly grasp

   the situation without visiting

   the site,  (other consultants,

   veg, people, etc.)

1.  Availability of aerial

   photographs and

   photographic services

   sometimes limited.

2.  Indicates little about

   sub-surface conditions.

3.  Indicates little as to

   precise causes of detected

   surface changes.

4.  Requires trained interpreter

   to evaluate results.

                                                              F   A
    Aerial photographs of a landfill site nay be readily available  from

    a local firm or it may be necessary to have the site flown.

    Available photographs generally cost about $10. to $30.  and having

    black and white photographs taken generally costs about $100.  to

    $300.  Special photography, such as color infrared or multispectral

    photography, with the necessary interpretation will cost up to

    about $2,000.  For this sum, a topographic map and a map showing

    vegitation stress along with a report of the result of the photo

    interpretation would be included.

    Geraghty & Miller, Inc.  1973.  Environmental Feasibility,

    Proposed Silver Sands State Park, Milford, Conn. Project Bi-T-55A.

    Report to State of Conn., Public Works Dept. Dept. of Environmental


<,^Geophysical well logging -  this method provides  indirect evidence

    of sub-surface formations that indicate the relative permeabilities

    as well as the depths of the formations.  The  most common borehole

    geophysical operation is electric  logging.  An electric log consists

    of a record of the apparent resistivities of the sub-surface

    formations and the spontaneous potentials generated in the borehole,

    both plotted  in terms of depth below  the ground  surface.  The

    measurements  of apparent  resistivity  and spontaneous potential  are

    related to the electrical  conductivity  of the  sediments, which  is a

    function of  the size  of the grains.   Thus,  fine-grained sediments

    containing silt and  clay will  have a  lower  resistivity  than clean,

    coarse sand  and gravel.   In addition, a leachate plume  may be

    detectable by an  electric log  as illustrated schematically in  Fi

V-  i
                              If ft ( it <-   c    f) U
                                   ,<> (,.!e  r->t.r'





                                  (/ «~-/xh i H.    U Uvw^<-

Electric well  logs  can be run only in  uncased boreholes.

Gartuna-ray  logging is  a borehole  geophysical  procedure based on
measuring  the  natural gamma-ray  radiation  from  certain radioactive
elements that  occur in varying amounts in  sub-surface formations.
The log is a diagram  showing the relative  emission of gamma-rays,
measured in counts  per second, plotted against  depth below land
surface. Bec^cfe, soroe  formations  contain a  higher  concentration
of radioactive elements than others, formation  changes with depth
can often be accurately determined.  For example, clay and shale
contain more radioactive elements, such as uranium; and thorium, than
does sand or sandstone.   In addition to interfaces bejtween two layers
of different materials,  the relative amount  of  silt ^nd  clay in
the formations can  be determined by the inflections 6n the gamma-ray
log.  Unlike electric logs, gamma-ray  logs can  be run in cased wells.

Geophysical well logs are used to supplement the  drillers' and
geologists' logs of the materials penetrated by the borehole.  An
example of the comparison between a geologic, electric and gamma-ray
logs is shown  in Figure S-36. An accurate evaluation of the sub-surface
geology at a landfill site is essential to the  determination of the
direction and  rate  of movement of leachate from the landfill and the
contaminant attenuation capacity of the materials through which the
leachate must  move.

Geophysical well logging generally is  applicable  only to those
landfill investigations which include  test drilling,  and is
therefore not  an independent tool. Gamma-ray logging can be used.


                                *"~\   UV;
                     ELECTRIC LOS

r-~Sr CLAYS-

however, to gain some understanding of the  sub-surface geology
at a landfill site from existing wells which may be in the
vicinity and for which no  geologic logs are available.

Since geological well logging requires specialized equipment
and trained operators,  the task would be preferred by a firm
offering geograp.iica4- services.  In some cases, larger we'll
drilling companies are  equipped to provide such services,
in which case the logging  operation can be included as part of
the well drilling operation.

                                                               B")  A  5"1
                                                               y\ A r I

1. Provides back-up data to

  substantial drillers and

  geologists log of borehole

2. Allows a more accurate

   determination of depth

   to formation change tha/j

   may be achieved with routing


3. Allows a geological log

   to be instructed for an

   existing well that was not

   logged when drilled.

4. May be useful in locating

   top and bottom of a

   contaminated ground-water

   body.   Selective log

1. Requires special equipment

   and trained operators and

   thus adds considerable expense.

                                                   *>~s i! *\
 The  cost of a geophysical well logging would  be  5300  to  $500 per
 day  depending on the complexity of the equipment and  size of
 the  necessary crew.   Normally five or six shallow wells  or
 two  or  three deep wells (several hundred feet) can be  logged
 in a day.   Interpretation of the logs by a geoohysisif*would
 cost about  $400  for  a typical landfill situation of six  100
 to 200  foot dee? wells.

 Campbell, M.D.,  and  J.H.  Lehr.   1973.   Water  Well Technology.
 McGraw-Hill Book Co.   New York.   681  P.

 Anon. 1972.   Ground  Water and Wells.   Pub.  by Johnson  Division,
 Universal Oil Products Co.,  St.  Paul,  M inn.  440 P.

 Parasnis, D.S.   1962.   Principals of  Applied  Geophysics.  John
Wiley &  Sons,  New York.


V/ater-Salanc5 Simplified

       The wafer-balance or water-budget method is the measurement of the continuity of flow

of water for any  given time interval and can be applied to any drainage basin, /tO),  In this

case, the drainage basin being considered is a hypothetical landfill ead the land immediately

surrounding it. The purpose of establishing a water-balance for a landfill are -to determine the

rate of leachate  generation and to establish which of the available pollution abatement proced-

ures would be most effective.

       The calculation  of the water-balance for a landf.ilI requires the measurement of numerous

physical parameters and can be a relatively difficult and expensive task.  For most landfill

investigation and monitoring work, however, a reasonable approximation of the magnitude of

the various water-balance components will be sufficient.  Methods of estimating each of these

components,  using as  much available information and as few field measurements as possible, are

given below.

       The s^even principal water-balance components of a  hypothetical  landfill are shown

by arro^, on Figure/-V.These are; precipitation and irrigation, surface runoff onto the landfill,

surface runoff from the landfill,  evapotranspiration, underflow, infiltration, and leachate.  Also,

given on Figurej'are references to the table or figure in this section which can be used to esti-

mate the magnitude of the components and the relationships between them.

Precipitation and Irrigation

       Figure £' shows average annual precipitation for various regions across the United States.

     a map,  however, can be considered  only generally accurate. Significant variations in

A^-G^Cf 0)



    . .  .

  /N 'V.'H-i	• •'<>
  /'Swv "~^/-- ;>0
                                                                ..<•• ii ..:-.•, i

                                                         Distribution of
               ' Xfo  . £
 wMVn     ,A^V.AV AV-  ^-^'j
fek  ({i
       in j:i nvt

   [BoscJ on 
  precipitation may occur in certain localized areas, especially in mountainous regions.  Sig-

  nificant variations may also occur with time, an abnormally wet year for example, eSl such

  abnormalities cannot be roffuUcd on a general map.  For tW reason!1, it is advisable to seek

  precipitation data specfic to the landfill site and><5 the year Immediately preceeding the Inves-

  tigatlon.  Historical precipitation records for weather sfations ncard'liu landfill :itc can be ob-

  tamed from the U. S.  Department of Commerce, National Oceanic and Atmospheric Adminis-

  tration,  Environmental Data Service, Asheville,  North Carolina. The locations of weather

  staHons for which data are available are shown on maps obtainable from the above address.

  Interpolation of the data from two or more stations can be made to mere closely approximate

  the precipitation at the landfill site.  For extended investigations or monitoring programs,

  it may be desirable to determine the precise volume of precipitation reaching the landfill

 surface.  For this purpose, a rain gauge would be installed In a suitable  location on or near

 the landfill. There are nmy types of rain gauges available and the selection of one would

 be based on the particular conditions of the monitoring program and atailable budget.

        Irrigation may be used on the landfill surface to maintain a desired vegetation growth,

 particularly when the landfill Is completed and its top surface is being used as a golf course

 or other recreational facility.  The volume of water used for irrigation should be measured

 with a flow meter and added to the precipitation.

.Surface Runoff.
'     ' •  ^ -  t

        The percentage of precipitation which flows onto the landfill from adjoining higher ground

and off the  landfill  surface to adjoining lower ground can be calculated by the  rational  runoff

formula described by Ven--JeChow.^(l)' A recsonable estimation  of runoff can also be made

fro-i the data presented in Table 1 . ft2) where the  rational runoff formula was applied to a

series of typical situations.  Areas and >lopes are measured by a survey and surface conditions

are determined by inspection.

Table 1 - Percentages of Surface Runoff for a 2.5 cm Rainfall


                                          Percent Surface  Runoff
Sjrface Condition
Pasture or meadow
cover crop
No vegetation-
not compacted




Clay or
Silt loam





        Evapotranspiration is the sum of water loss by evaporation and transpiration (plant water

consumption).  Methods of calculating evapotranspiration are given in the hydrologic literature

(see Yen Je Chow) /(0)/  However, the large number of variables that must be  measured to per-

form the calculations make ir a difficult process.

        Estimation of evapofranspiration from available generalized da fa, such as potential

 avopotranspiration maps or annual wafer consumption figures for different plant species, may

 be misleading. This approach cannot account for numerous specific variables such as soil type,

 soil water available and veg/'tafion density. Since evapotranspiration  from a landfill surface

 may be-anywhere from insigificant to the single most important mechanism for the removal
 of water from a Idnfill surface, an accurate estimate of the actual magnitude of evpofrans-
piration, from the specfic site, and at the specific time of the investigation, should be ob-


        Because ot the difficulties,  in arriving at an accurate figure for actual evapotrans-

pirafion, it is suggested that professional assistance be obtained.  If a hydrologic consultant

is retained for the landfill study, he will be able to estimate  actual evapotranspiration for

the specific case involved.  IF such a consultant is not used, information on evapotranspiration
                                                                 e* ' *• •'
rates for an area will often be available from a local agricultural-test station,  a nearby

United States Geological Survey field office,  or possibly the agriculture department of a

nearby university .


        Underflow is defined here as the rate of ground-water flow from adjoining areas directly

 info the landfill.  This condition will  occur only if the base of the landfill is below the water

 table.  A sjecond necessary condition, however, is that the landfill adjoins or is situated near

an area of elevation substantially higher than the base of the landfill, i.e. that there is a sig-

nificant water  fable gradient beneath the landfill.  If the  landfill is situated on level ground

                                                           i"~ u a
 and substantial percolation of water through the landfill is occurring, leachate being generated

b/ the percolation will move away from the landfill and  in directions and underflow, as defined

above, will not occur. (See Figure?')

        Precise measurement of underflow,  it it is occuring, it not feasible. A determination

of the occurrence of underflow, and a reasonable approximation of its rate  can be made, how-

ever, by means of a relatively straightforward hydrologic investigation.  Figure5'is a schematic

diagram illustrating the method for estimating the rate of underflow. This process requires the

drilling and testing of at least two wells andr4r"therefore.considerable expense  will be  incurred .

The drilling, however, would normally be necessary for other determinations -onywoy (e.g. water

quality)^  a*..(


until almost all of the refuse has reached field capacity. For the present- discussion, if is assurm

that the landfill has reached ifs field capacity.

       Calculation of the rate of percolation of precipitation and irrigation into the hypothetica
landfill is shown on Figure X.  Calculation of rhe rate of leachate generation follows by adding

the value for underflow.  Direct measurement of percolation is possible using a sub-surface water
trap such as the one shown in Figure 5'  If infiltration is measured  directly, somewhat more con-

fidence can be placed in the calculated values for leachate generation, surface runoff and

evapotranspiration .

Pollution Abatement Based on Water-Balance

       Based on the results of  a hydrologlc investigation of the landfill site,  it may be determined

that reduction of the leachate  generation rate is the best course of action, Bother possible courses

of action would include leachate removal,  hydrologic barriers,  physical barries, etc).  In this case,
                                                                         A    '
the, existing parameters such as side slopes vegetation type, etc. which control the components
shown on Figure^ can be altered to increase C and D and decrease B,  E, and F and consequently

decrease G .  The degree of alteration required  for each parameter to achieve the desired reduction
in leachate generation can be determined by calculating the effect the proposed ollu,viuliun will

have on the \oriors components of the water balance.  By this means, various alternatives for

modifying the landfill can be compared and the optimal method selected.

       The cost of a water balance  study by a consultant,  for a landfill where underflow is not a

problem would be about $1,000, including  both the field and office work.  In many situations,

"f•„  •'[
. I  I <>V\ <• I I .'>.,\   A


                                    '  •. *"*/'.    '

                                   STEEL RODS
                                    FIBERGLASS  SCREEN
                                     STRIP TO FASTEN

                                    METAL OR

                                     PLASTIC BOX

                                                             >. n   A  r.*= "T7-
                                                          &  ••-.
                                                    -^.    i4».

       the necessary field work would be accomplished during other tasks, such asfhe field inspection,

       one the cost would be reduced to about $400.  If underflow were a significant problem, the


       cost of the water balance study would be closely tied to the drilling program, as multiple-

       use wells would be installed and the cost spread out over seveal tasks.
  6j  Chow,  Ven, 1964.  Handbook of Applied Hydrology, McGraw-Hill Book Co.,  New York.
       Hughes, G. M./R. A7London, and R. N. Farvolden,  1971.  Hydrogeology of Solid waste

       disposal sites in Northeastern Illinois.  U. S. Environmental Protection Agency publication

       No.SW-12d   154 p.

     >.  Fenn, D. G.,  and K. J. Han ley,  1973.  Use of the water balance method for predicting

       leachate from sanitary landfills.  Office of the solid Waste Mangagement Program, U.S.

       Environmental Protection Agency.  Unpublished manuscript. 55pp.


    ->  -       '   - <     •    r  i -\.  ,L ' *•-*!-   "•*	     f   -      -  ' s „..  *  - i. •
                       B. • I .1 *J * .   *- »• -•••••-     -  ri'»'-»->»  - t i if *      -^-f-- I   u " "   -  —

                  • -V/S-TW
         N -ML , ^ - !.   U J lC P  I -«    I o 2 O «* «•-'

                           GEKAOHTY  6 MILLED,  IhC
Well Technology

                                                               GERAGHTY  ft MILLER, IMC.

   DRILLING METHODS                                            — DRAFT —
   DrfVe P°?nfs - ln fh?s me'hod of d"""9, a li-or 2-inch diameter drive point is attached

   to a 2-?nch pipe and driven to completion depth with a sledge hammer, drive weight,

   mechanical vibrator, or pneumatic hammer.  The point can be driven to approximately

   30 feet by hand, and up to 100 feet if a mechanical drive weight is used, but only if driv-

   ing is done in sands or finer grained sediments that offer little resistance to penetration.

  Boulders cannot  be overcome.  Powell  and others  (1973) report using a mechanical vi-

  brator to drive points  to depths of 65 feet.  Drive points, because of their small  diameter,

  are used In areas of high water table (near-surface)  from which water can be  removed by

  suction pumps, for example kitchen pitcher pumps or centrifugal pumps.
      Reliance on a drilling contractor to install drive points is unnecessary.  Local  inves-     ?

 Hgatlen. can drive them with a minimal investment in equipment and manpower. The first     *

 step Is to bore a vertical hole as deeply as possible with a hand auger slightly larger than

 the well point.  (Figure 17). The drive point is attached to a length of ii^p.^ foot

 lengths are preferable) and placed in the augered hole. A drive cap is placed on the top

 of the casing prior to driving.

     Casing can be driven with a tool similar to the type used for driving steel fence posts,

or  by drive weight suspended from a tripod or derrick.  Drilling will be more efficient  if

there is a source of power to lift the weighty they can weigW 75 to 450 Ibs.  A^efl^d
                                                      i^V -     '
orwcuportable-was^boring-rig-can be «sed-c^one^an be-i^ve^using a rear axle of a

auto-and tire rim for cathead.  Drive points can also be driven with a sledge hammer, but


                                                               GLRAGHTY tt MILLEH,  INC
                                                                    -DRAFT  —
j^  fill Simp*. to*« for dri*m* w«» P«"« «»
 depth* of 15 to 30 ft.

                                           _2-                 GF.RACHTY  a MILLER. INC.

this is difficult and slow going unless the investigator is a J

driven, it is turned slightly to keep the threaded joint tight.


 1 .    Inexpensive.

2.    Easily installed by hand, to limited depths,
 3.    Closely spaced vertical samples can be   .
      collected during drilling.              <^-

 4.    Can expect a good seal between casing
      and formation, little or no vertical
           GEHAGMTY  tt MILLER,  INC


        1 .    Difficult to develop and sample
              if water  table is below 15-20 ft

        2.    Extreme depth limitations.appli-
v             cable tolhallow work primarily
 \            less than 30 ft.
, ' N^--^« 3.    No formation samples, only in-
              foenation on subsurface material
              penetration rate (bjflow counts, et

        4.    Only certain types of pumping
               .. ,- ,,wr..-v can be used.
        5.    Drive point screen may become
              clogged wih clay, if driven
              through a clay unit.

        6.    Can be  used only In unconsolidate

                                                             GERAGHTY 8  MILLEK,INC.
                                         -4-                     -DRAFT-

Augers - In auger boring, the hole is advanced by rotating and pressing a soil auger info
the soil and withdrawing and emptying the auger when it is full of soil. As much as possible,
the borehole is kept dry because water tends to prevent accumulation of soil in the auger.
                                  ?                                   -                  y
Hand augering as anyone  who has dug a post hole knows, can be easy or difticult depend-
ing on whether or not clay and sand or gravel, respectively is being, removed. Small
diameter helical  or posthole augers can be used to advance 2 to 12-inch diameter holes
by hand to depths of 20 to 30 feet (Figure 18).   If a tripod and pulley are set up to aid
in pulling the auger from  the hole, depths of 80 feet can be reached.  If the hole can be
kept open below the water table, usually only in cohesive material, a screen and casing
can be set, backfilledjand developed.

     This process becomes much  simpler and less time consuming if power augers are  used.
Here,  flights of spiral  of hollow-stem augers are forced into the ground while being  rotated,
and the spiral action of the augers conducts cuttings to the surface  (Figure 18).  On comp-
letion of drilling, a small diameter casing and well point are pushed to the desired depth.
With bucket augers, a  large-diameter barrel fitted with cutting blades, (up to 48  inches
in diameter) is rotated  into  the ground until it is  full.   The earth-laden bucket is fhen
brought to the surface, pulled to one side, and dumped. This process is repeated  to
completion depth.  Bucket augers would not normally be used  in landfill investigations,
and they are not evaluated  below.

     Power auger^can be tied very effectively in cohesive soils.  On the other hand, these     /
augers are not well suited for use in very hard or cemented soils,  and they often fail to
retain very soft soils and fully saturated cohesionless soils.  However,  if setting a drive point
is the  ma in purpose of  the hole, slups or cave-in of the hole in cohesionless sediment is
not a major drawback.

                                                              n  MII.I.EI:,  ir,

                                                          D  R A F T -


                           V\V.  :-..

                           i — A £A3TH DqiL'- WITH CONTINUOUS HELiCAL A'JGEP

1 .    Inexpensive.
2.    Small, high-mobility rigs can get to
      most sites.
3.    Can be used to quickly construct
      shallow well  clusters.

4.    If borehole reaches refusal depth too
      soon, set up time is low and rig can
      be moved rapidly.

5.    No drilling fluids introduced into
      the borehole, no possibility of
      diluting formation water.
                                                           GERAGHTY 8  MILLER, IMC

Limited penetration, normally
100 feet, max. 150 feet.

Vertical leakage through sedi-
ment left in borehole, through
which drive point is forced to
completion depth.  No way
to isolated screened zones of

Careful attention during drilling
is required to get a correct log
of formation materials penetrated.

Unable to collect ground water
samples during drilling.

Core sampling is possible^,only
if hollow stems augers flights are

Can be used only in unconsolidate

Borehole will collapse in cohesion
less sediment.

                                          -6-                 GErtAOHTY  a MII.LEP, INC

                                                                  -DRAFT —

 Wash Borfng - A  waih boring  is advanced partly by a chopping ana rwisring acnon or a cnisei-
 shaped bit and partly by the jetting action of a stream of water pumped through the drill rod

 and out the bit^  (Figure 19). As the bit penetrates the formations,  the casing sir.ks of its own

 accord due to the washing action of the bit alone. Currirtgs are carried to the surface by

 the water circulating in the cnrjlar space between the  drill pipe and casing.  The drill

 string  is lifted and dropped to get a cutting action with the bit at the same time it  is  rotated

 to make the bit cut a round hole.  These operations, as well as the pumping,  may be performed
 entirely by hand,  but a small ^motor-driven winch and pump are generally used.  A closed

 system is used to recirculate the drilling water.  Water is pumped from a pit into the  drill

 string and out of the bit.   This water, after it circulates from  bottom to top of the borehole,

 is conducted back to the pit where  the cuttings settle out.  Normally, small pits are  used to

 reduce the volume of water required.  As a result, cuttings have to be cleaned out of the

 pit  at regular intervals.

     The drill rod Is generally 1  to  2-inch black iron pipe.  Casing is required to keep the

 hole open in soft  clays or sand and  gravel, but is often not necessary in stiff clays or similar

 cohesive sediments.  If the borehole stays open by itself, casing and screen are simply lowered

and backfilled to construct a well .   If casing is required to drill, slip screens are set by the

casing pull-back  method.

     Drilling-equipment is simple/and-readily-available to-loccrl investigatorr'who'wishisSr-t'O"

doJJieir.own-botings. The basic  units are a tripod, a pump, and a  cathead.  The only comp-

onents that need to be purchased from a drilling rig company are the water swivel and the drill

bits, although the bits can be easily fabricated in a metal-working shop.

                                GERAGHTY  a  MIL'-ER,  IMC
Fifr^g^VV A 5bt-B€>«4NO

                                                    CtKAMITY  L\ MILLE.-',




Inexpensive and light1 equipmenh.grill-
ing contractor not required.    ~

Excellent for shallow bore holes in un-
consolldated sediments.

Can get vertically spaced ground-water  f
samples if drive point is forced ahead of
borehole and pumped.                  ^

Drilling equipment can get to almost any
5.    Core samples can be collected.
Slow,  especially at cleprh .

Maximum depth of 100 to 150 feel

Cannot penetrate boulders and
wash up gravel.

Difficult to develop and sample
if water table is deeper than
15 to 20 feet.

Can be used only in unconsolidate

Wash water can dilute formation v
must be taken into account in
vertical sampling.

Interpration of geology from wash
samples requires skill.

Can set only short sections of
screen  without difficulty.

                                                              GERAGHTr  8 MILLEK, l.'iC


 Jet Percussion - The drill fools and the drilling action of the fet-percussion  method are the

 same as those described for wash boring, however, casing is driven d'uTing drillTrig with a

 drive weight'.and not allowed to advance of its own weight.  Normally, this method is

 used to place 2-inch diameter casing in shallow, unconsolidated sand formations, but has been
 used to install  3 * 4-inch diameter casings to 200 feet. Screens have to be set by the casing

 pull  back method.

     Most jet-percussion rigs are moderate-sized pieces of equipment and drilling contractors

used to working in unconsolidated sediments will probably be the best source of a rig.

                                                           GERAGHTY a  MILLED, INC
                                                               -DRAFT —
 Air Chamber
   Pump |

/Sucrion Hose

 Settling Tank
                                                                     Drill Rod
                                                                    High Pressure
                                                                   Drive Shoe
                                                                   Cross-Chopping Bit

                                                        GERAGHTY  &  MILLER, 1,'iC
1 .    Inexpensive.

2.    Simple equipment and operation.

3.    Good seal between casing and formation
      prevents vertical leakage of formation

4.    Can obtain a reliable formation water
      sample at completed  depth.





     Use of water during drilling
     can dilute formation water.

     No formation water samples
     can be taken during drilling.

     Poor soil samples because fines
     are washed out of sample.

     Small diameter (2in.) and shallo
     maximum depth (125 ft.) limits
     usefulness of this type of well to
     water sampling at shallow depths

     Large number of wells requirec.
     at one location to obtain closely
     spaced samples throughout the
     contaminated thickness of the
        5 •'.^;     !
     Can^e used on unconsolidated
     sediments or weathered rock.

                                                              GERAOHTY  tt  MILuEH, IN'!

                                                                  -DRAFT  —

 Cable-Tool Percussion - In cable-tool percussion drilling, I

 regularly lifHng bnd dropping a heavy string of drilling tools in the borehole (Figure 21).

 The drill bit breaks or crushes hard rock into small  fragments and in soft, unconsolidated

 sediments, loosens the material.  The up and down action of the drill string  mixes the

 crushed  or loosened particles with water to form a slurry or sludge.   If no water is present

 in the formation being penetrated, the necessary water to form the slurry is put into the

 borehole. Cuttings are allowed to accumulate until they start to lessen the  impact of

 the bit,  and then are removed with a bailer or sand pump.

     A cable-tool drill string consists of  four units:  the drill  bit, drill stem, drilling jars

 and rope socket.  The  bit provides the cutting edge of the drill string, the action of which


 is jinhanced by the weight of the drill stem.  This weight also acts as a  stabilize^keeping

 the hole straight.  The jars are a  pair of sliding, linked bars which provide a play\in the

 drill string .of 6 to 9 inches.  If the tools become stuck, the jars permit successive upward

 blows in the attempt to free them  rather  than a steady pull on a  cable which might part.

 The shaking and vibrations produced by the jars helps in freeing a stuck  drill string.   The

 rope socket connects the string of tools to the cable and allows the tools to rotate slightly

 with respect to the cable.

     The bailer consists of a section of pipe with a check  valve at the bottom, and is filled

by an up and down motion  in the bottom of  the hole. Each time the bailer is  d/ipped, the

valve opens, allowing  the  cuttings slurry to move into it.  The up and down  motion ?s con-


                                                             OKI'ACHTY  iA Mil '.Ef<, \t>(.

                                          ~n~                    -DRAFT —

 tinued until the boilei is full.  At this point,  it is brought to the surface and the contents

 clumped on the ground. The sand pump is a bailer that is fitted with a plunger so that an

 upward pull on the plunger tends to produce a vacuum that opens the valve and sucks sand

 or slurried cuttings into the tubing.

     Casing is driven by attaching a drive clamp to the drill stem  and the reciprocal action

                                                                           A i1 <•  K?w A f
 of the rig hammers the casing into the ground  as the clamp makes contact with the top of the

 casing.  Operation can be speeded up by drilling ahead  of the casing,  but only if the hole

 will stay open by itself.  If drilling open hole and there  is a cave in, the drill string could

 be tapped.  Cautious drillers}therefore,  rarely drill ahead of the casing unless they are

 going through rock. Normal^ procedure in unconsolidated sediments is to drive fhe casing

 into the formation and then clean out inside the casing with the drill tools.  This is slower

but safer than drilling ahead of the hole.

                                                      GERAGHTY  ft MILLER, INC.

 '„•._ .  Inexpensjye>-Tf non union drillers-'dre
       inu&rved.      ~~~            ""
      Simpl-3 equipment and operaHon.

      Good seal between casing and formation
      if flush joint, casing is used.

      Good disturbed soil samples, know depth
      from which cuttings are bailed.

      Core samples can be collected.

      If casing can be bailed dr/i w/jfhout
      sand heaves, a formation water sample
      at that depth can be collected.

      Can be used in unconsolidated sediments
      and consolidated rocks.

      Only small amounts of water are required
      for drilling.
Ov r^L. ^j^f ,
'lu 5^.—-,

                                                   1.    Slow.

                                                   2.    Use of water during drilling can
                                                        dilute formation water.

                                                   3.    Potential difficulty in pulling
                                                        casing in order to set screen.

                                                   4.    No formation wet er samples can
                                                        be taken during drilling unless
                                                        open-ended casing is pumped.

                                                   5.    Heavy steel drive pipe -s used
                                                        and could be subject to corrosion
                                                        under adverse contaminant char-

                                                   6.    Cannot run a complete suite of ge
                                                        physical well logs because of stee

   '/~&  ill
    I          I'  ;

 ///   .     .   '
//         il
 .'  j    s :1  ! -.• I   ii

 J~ i  SN iTlU
 .'   s-  ;! ;  i! >• U JT
 ^^x v i. '! i' * e=~
'.''OM  — JC.^  f°*T=T


                                               TWO-CONE BIT
                                                                        L>ras-t\pe hits >*i«h rrplnceaN
                                          -13-                GE.KACHTY a  MILLEP, IMC
Hydraulic Rotary - To drill a hole by the hydraulic rotary method, a roraring oir oreaKb
up the formation and  the cuttings are brought to the suiface by a recirculating drilling
fluid (Figure 22).  Drilling mud  is pumped from a settling basin, through a water swivel,
and down the hollow interior of  the drill rod. At the bit, nozzles direct the fluid to
efficiently clean cuttings from around the bit and it then flows upward in the annulus,
carrying the cuttings to the surface.  Here, the fluid is discharged into the mud pit and
the cuttings settle out.  At the other  end of the pit, the water is sucked into the pump
to circulate down the drill rod again.

     Teh' drill string consists of the bit, a stabilizer, and the drill pipe.  Two basjrf
                               c                                             f
types of bits are used:  roller bit in rock and -consol i doted sediments and drag bi£ in un-
consolidated materials.  Roller bits have conical rollers with hardened steel teeth of
various lengths, $ spacing and number dependent on the type of material to be drilled.
Some rollers have inset  carbide buttons for drilling in hard, tough rock. As the rollers
rotate, they crush and chip the formation material.  Drag bits have fixed blades, the cut-
ting edge of which is surfaced with carbide or some other abrasion-resistent material.
DfiiUn^actionTs-the-resull- otthese-bJades -scraping material off the- borehole- wall .
     The bit is attached to a heavy,  weighted section of the drill string called a drill
collar or stabilizer.  This weight just abov~the bit tends to keep the borehole straight
and vertical .  The drill rod connects the stabilizer to the kelly be* and  and ranges in
       •\i • »- •                   £                          OT  ."'-''"-
outside ebember from 2 3/8fto 4-inches.  The kelly is a fluted bar which passes through
       f.                       f                            A
a rotary table, which imparts a rotary motion to the drill string.  When- the.iength  of the
   y^ has been drilled,  a new section of rod  is added and drilling is started again.

                                                          Cti-iA'JHTY i\  MILI-CI!, IN'
1 .    Fast .

2.    Dilution of formation wafer Is limited
      by formation on a filter cake on bore-
      hole walls.

3.    Formation water sample can be obtained
      with a special technique.

4.    Good disturbed soil samples from known
      depths if travel time of cuttings up bore-
      hole is taken into account.

5.    Flexibility in final well construction,
      such as screen placement.

6.    Can run a complete suite of geophysical
      well logs.

7.    Core samples can be collected.
1 .    Expensive.

2.    Complex equipment and operatioc

3.    Potential of vertical movement
      of water in formation stabilizer
      material placed between casing
      and borehole wall after comple-
8.    Can be used in unconsolidated sediments
      and consolidated rocks.

                                                               GERAGHTY  8 MILLER,  INC.

                                           -15'                    -DRAFT —

  Air Rotary - As in hydraulic rotary drilling, a rotating down-hole hammer is used to break

  up formation material by percussion, but rather fhan a  liquid carrying cuttings to the surface,

  high velocity compressed air is used.  Down-hole hammers are essentially pneumatic hammers

  similar in operation to those seen being  used to cut up pavement by road repair crews. Nor-

  mally this type of drilling equipment is used in rock because of fantastic penetration rates

  compared to cable tool or mud rotary drilling;  drilling rates of one to two feet per minute

 are not unusual.   Unfortunately, down-hole hammers larger than 6 inches are not readily

 available, limiting the size of the borehole that can be drilled.  Much  of their speed ad-

 vantage is lost when conventional roller cone bits are used. However,  drilling water is

 not required, eliminating a logistics problem that can become difficult especially in arid

 regions. Most rigs are equipped with a small mud pump so they can drill a conventional

 rotary hole through unconsolidated overburden on top of the rocks.  When the hole is fin-

 ished, casing is rock to prevent caving.

     Advantages                                            Disadvantages

                      Same as discussed in hydraulic rotary  drilling

    A minimum upward air velocity of 3000 feet/minute is required to lift cuttings to the

surface. When drilling a four inch diameter hole with 2-3/8 inch rod at least 150 cubic

feet/minute (CFM) of air are required to  lift cuttings.  If a prolific aquifer is penetrated,
the hammer may be "drowned out", -re^the compressed air cannot lift the  volume of water

entering the hole to the surface.  At 3000 ft/sec air velocity, this threshold is met at about

50 gpm  in a 4 inch hole,  and at about 150 gpm in a six inch hole.  When this happens,  a

                                                              GtUAOHTY  -i MIL.LEI', IN'.

                                           "16~                   -DRAFT--
                                             v..- .-..-«
 larger air compressor is required or drilling must »w4teh to the hydraulic rotary method. Air

 rotary rigs are available with compressors capable of supplying 1100 CFM at a pressure of

 250 psi.
 Well Casing & Screen Materials

     Landfill leachate can be characterized as  a stron e.'ectolyte which may be corrosive.

 Specific characteristics of the leachate will  depend on the type of material accepted by

 the operators.  Therefore, some thought must be given to the materials used in monitoring

 well construction in order to prolong the installation's operating  life to at least match

 that of the landfill. This  is  not an adequate design criteria.however, the monitoring well

 should be serviceable for as long as required after the landfill is  completed. Review of

 comoarison tables of various pipe materials to chemical attack (Robintech, Inc.T indicates    '•-..-.

 that PVC pipe is resistant to most chemicals, with the exception  of ketones,  esttfers, and

 aromatics (amonf the more common chemicals),  when compared to the other normally-used

 well casing,  steel pipe,   PVC casing (p*p») is a nonconductor and will not be involved in

 electrochemical reactions as we4J,  for example, a steel casing and brassjf or iron well screen.

 Nor will it normally interact with the leachate as will steel casing.

     From a leachate sampling standpoint,  PVC  is very attractive.  Because of its chemical

 inertness, it will contribute little in the way of  chemical constituents to a leachate sample ex-

     .                                                                           -|x i •
cept in the parts per billion range.  Steel pipe can be expected to contribute at least-ion, and

probably other ions to a sample.  Of course,  this sample contamination can possibly be avoided

by proper flushing of the well  before collecting  a sample in both  steel and PVC casing.

                                                               GERAOHTY  8 MILLER, INC.

      A major drawback to PVC casing is its lack of strength.  Landfill equipment or vandals
 can easily snap off a PVC casing projecting above ground surface.  Therefore, special  well
 protection measures (described in the Well  Security  section) must be taken.  In spite of all
 this, PVC casing and screens appear to be the best materials to use in constructing landfill
 monitoring wells.

     Actual well  construction,  however, will  be dictated by a variety of constraints,  such
 as drilling method, aquifer type and formation materials, cost of well consrruction materials,
 •-^'                            I
 east of installation, and personal prejudices,  among others.  Proper construction materials
 can be best evaluated for each situation by a  person familiar with landfill investigations,
 but a person not familiar^ can fall back on  a drilling method that will allow  PVC casing
                   ^ '           .
 and screen to be  installed and be confident that the  well  will last and not bias the samples.

 Well  Security

     Once a well  has been completed, some measures must be taken to protect the installation
 from:  1)  normal  landfill operations, especially heavy equipment and,  2)  vandals.  In areas
 being actively landfilled, provisions have to be made for extending the well  casing and its
 protection above  the active  level of the fill.  An installation capable of protecting the
 monitoring well and being added as the depth  of the fill increases is shown  in Figure 23.

    Construction  of this protective  installation is straightforward and inexpensive with a reason-
able likelihood of remaining undamaged by  landfill equipment on vandals.  To do this,  a 10-
foot length of steel casing several inches larger in diameter than the monitoring well is  placed

                                                             GERARHTY a  MILLEff,  In'.

over it. This casing is grouted in place with a cement collar at least four or five feet deep
to hold it firmly in position. Although this will net withstand a run-in with a compactor or
bulldozer, it will  withstand attempted vandalism.  The casing should be threaded so that a
screw cap can be used to close the well. Two heavy duty,  hardened steel hasps welded on
opposite sides of the cap and casing will allow the well to be locked.  As long as  heavy duty
hardened steel hasps and padlocks (capable of withstanding a 48-inch bolt cutter) are used,
the efforts of even the most determined vandals will be in vain.  If this type of installation
is broken into, it will be for thopurpooo O6 sabotage,  not simple vandalism.

     Unless this well is highly visible, chances of it being struck by equipment during normal
landfill operations are fairly high. To avoid this, a sample tripod constructed of timbers
(railroad ties or  equivalent) should be constructed over the well and crowned with a bright-
ly colored object, such as a flat or painted tire (Figure 23).

    When landfilling threatens to overtop the installation,  the tripod is temporarily knocked
down,  additional casing added to the monitoring  well and protective shell, and placement
of trash and cover is continued around the well.  If this procedure is followed, only a slight
interruption in the normal course of landfill operation will  be required to protect the mon-
itoring well for future sampling.


   Woter Withdrawal Methods
       Water can be withdrawn from wells by a variety of methods including:  bailers, thief

   samplers,  pumps, or compressed air.  Theprimary consideration in collecting a sample is

   insuring that a_l]_ stagnant (standing) water has been removed from the well casing before a

   sample is collected.  On cessation of pumping, water standing in a well begins to stratify,
   with water in the screen mixing with formation due to normal ground-water flow, and

   water above the screen becoming more and more isolated because there will be little or

   no vertical mixing with the water in the screen.  Improper well construction can cause all

   the water in the casing to be stagnant because of vertical leakage of leachate down along

   the well casing to the screened zone, or vandals dropping material into the well.  There-

   fore, to obtain ground-water samples representative of chemical quality In the aquifer at  "

   the time of sampling, at least one volume of water standing in the casing and discharge

   pipe must be removed before sampling.

       However, removing one volume is no guarantee that the stagnant water has been flushed

   from the well - four or five volumes are required tcrteronTt/feSofeTide;- If this seems like
    •^-             <-:.£.'>".r>
   0"ho*=of effort-just to-get a water sample, consider the expense  of chemical analyses and

   the possibility of having to repeat an analysis because stagnant water was sampled. Re-

   member that the stagnant water may contain material introduced from the surface,  inadvert-
                                                                                 rl.  -    l)
                                                                 -      -f't-tf^r-  -.t   •
  ently or deliberately,  which would result in analytical results eiavatcd-beyond-ochjol aquifer

  water quality. This might ultimately result in adverse actions by an enforcement agency,

,ajl because of an improperly collected sample.

                                                            GLKAGHTY  a MILLEH, IMC.

. ,v
                                                                          \ '.• --:-^. \ •".<.-. . •>••»'
                                                                                      —. -' .*••   >.

                     .y  ,.,-*

                     AV-' -\\'. O-
                                                                         v \- y-
                                                                         *•.. , ^. ^\_  i  „ ii-A •


                                                   M                a ^ >-A J

       In light of this discussion, bailing by hand is not a recommended well sampling method

 unless adequate precautions are takun.  Bailing is accomplished in small diameter wells by

 lowering and raising a weighted bottle or capped length of pipe on a length of rope.  Rarely

 can a sufficient quantity of water be removed to adequately eliminate stagnant water from

  •                  "*"" f
 the sample,  unless innumerable, time consuming trips in and out with the toiler are made.

 Often, people sampling a well will use the first bailer full of water as the sample because

 of the easf with which the sample can  be collected. The reliability of this sample is nil

 ond thi£ fact must be impressed on the sample collector.  Of course^ in  situations where

 the well can be bailed dry or there is only several feet of water in the bottom of a shallow

 well, representative samples can  be obtained with a bailer because the casing can readily

 be emptied.

      Where the water-table is within  suction lift, small-diameter wells can be sampled

 with centrifugal, peristaltic or pitcher pumps.  Peristaltic pumps have rather low pumping

 capacities but are attractive because the sample Is conducted throug inert silicone rubber

 tubing,  reducing the possibility of sample contamination by constituents  from the sampling

 apparatus. Small, highly portable centrifugal pumps are available with  pumping rates from

 5 to 40 gpm, and removing stagnant water and flushing the discharge set-up clean will pose

 little difficulty, allowing collection of representative samples.  If concentrations  of less than

 1 ppm are being investigated, extra care mast be taken in sampling, ond in the extreme ppb

range, the peristaltic pump would  have to be used.

        Pitcher pumps can be easily carried to a site, screwed onto a well, and used to purrp

  a sample.  No power source is required other than the investigato^ana^^costs are low,
                                                                   '• 1
       As an alternative to these pumps, an inexpensive bailer pump can be constructed from read-

 ily available materials (Leonard,       ).  This pump consists of a length of garden hose with  "

 a foot valve at its bottom end and fittings at its top end that allow a vacuum to be applied

 to the hose. A water sample is moving the hose up and down, activating

 the foot valve, and the partial vacuum assists in bringing water  to the surface. Vacuum is ob-

 tained from an automobile engine.  Keep in mind, however, that this sampler should be used

 where the well  contains only a small volume of ^ter'^^dearfng stagnant water &X%f

 the casing does not become an inordinately time consuming process.

       An inexpensive air lift sampler can be constructed from polyethylene or any reasonably

 flexible tubing as shown in Figure 24.  Because the tubing is flexible, it can  be readily

 coiled and moved conveniently from well to well.  Primary limitations on the sampler are

 the amount  of air pressure  that can be safely applied to the tubing and a source of compressed

 air. A high-pressure hand pump ^ serve nicely  fo/lhallow water table buttmall air
                                    A              '•                 j    A

 compressor may be required for lift greater than  30  feet. The advantage of this sample is

 that it can be -^ftro fit the monitoring well -vafivices-o^s7not^?'37TTnc1r
                                                                       'P  • "•  ;;- 7
                                                                  IL-*' (JM^-i j*   3
      Somewhat more elaborate pumping equipment is required in small-diameter wells

where water level is below suction lift. The easiest, but not the driest,  way to collect

      A  . j^Mi
a sample is topiOESh airline dSton the well and blow the water out.  However, trying to

adjust airflow soi that water flows smoothly over the top of the casing instead of blowing

violently into the air is a difficult task. Addition of some simple, relatively inexpensive

hardware to cap the well can make sampling a straightforward and easy process. Sommerfelt

and Campbell  (1975) have described such an installation (Figure 25) and  Trescott and Finder

(1970) have pumped water from as deep as 190 feet withyjFype of Installotion »  Air pressure
   W.y»flO/><.Jl    _                                '
can-eemerrom a sflg^tt'gasoline powered air compressor, an engine air pump, or a compressed

air cylinder.   The source of air pressure selected will depend on well site accessibility

and budgetary constraints.  If a well can only be reached on foot, low-volume, high -

pressure hand pumps (available in stores handling racing bicycles) can be used to supply

                               /" \ye>>lv;v^«-NT'^^vr ~tU«'.. |n:-£V' r<2-j \f \
 ir pressure of up to 160 psi.     [        II    i i    L    -\      -f"         J
                               V  O f 
,.^-  Sc ^
                                                                                 OQ   A   L
                                                                                 K A
                                4 -*r Vj •••—t
                            Fig.4 SchMTMtic diagram showing th* construction and

                            mechanism of ttw pump.

                                   REFERENCES CITED
1.  Anonymous 1972.  Ground water and wells.   U.O.P. Johnson Division, St. Paul, Minnesota.

2.  Hvorsley, M. Juul 1965. Subsurface exploration and sampling of soils for civil engineering
    purposes. Engineering Foundation, New.York, NY 521 p.

3.  Matlock, W.G. 1970.  Small diameter wells drilled by jet-percussion method.  Ground Water
    8 (l):6-9.

                                              Htfss0*' IS   B ffi  A{| n jo. \i  IA  'XV&&1 t> .'I
                                              E L  I Ivi I I\J A w V
                                         _   &i»wl!¥lli is/nt %  I
                              CHAPTER 6

                        INDICATORS OF LEACHATE


As  can be seen from the composition data presented in Chapter 3, leachate

represents an extremely complex  system containing soluble, insoluble, organic,

inorganic, ionic,  nonionic and bacteriological constituents in an aqueous

medium.  Figure 6-1 schematically  depicts  an extensive characterization of

leachate by means  of physical, inorganic,  bacteriological, and organic


In setting up a monitoring program, one must consider all  the factors

affecting the quality of the pure  leachate and "leachate-enriched ground

water" and the resultant environmental  impact  including:

          . purpose for monitoring

          . background quality of ground water  at the site

          . other sources of ground-water  pollution

          . hydrologic renditions of  the site and the resultant

           monitoring network being utilized

          . climatologic influences

          . costs and availability  of  manpower  and laboratory


          . site history

A major item in any monitoring system will be  the costs  for  the  analytical

measurements.  There are several ways these costs may be minimized,  yet


meet regulatory  requirements,  the most  important being proper selection

of indicator parameters  to  be  monitored.

It will be  the function  of  the regulatory  agency to specify monitoring

requirements for land disposal sites.   Some  of  the necessary analyses

will be time-consuming and  relatively expensive.  The regulatory agencies

should maintain  flexibility to consider approval for substitution of a

less expensive analytical indicator  if  the paramenter requiring the more

expensive anslysis can be accurately inferred from the simpler, less

expensive analytical indicator.   An  example  of  this would be the substi-

tution of COD  (Chemical  Oxygen Demand)  analyses for a portion of the BOD5

(5-day Biochemical Oxygen Demand)  analyses if it can be shown that a

satisfactory correlation exists between the  two parameters.  Monitoring

land disposal  sites can  also be looked  at  in the quality control sense.

Here, a regulatory agency can  allow, at least for the frequent monitoring,

the selection  of indicators be subject  only  to  the requirement that Ouf£oa.|

control &**y»*m»»''iaetuXAwground-water quality -av\«t permit specifications]^tn

It is here  that  a strong effort should  be  made  to utilize inexpensive

indicator analyses which can provide quick,  accurate and correct information

of those indicators requiring  more expensive analytical techniques.  Prompt-

ness of analysis is quite important  since  having the results for early

action will greatly simplify control requirements and sample degradability

effects will be  minimized.   As an example, conductivity can sometimes be

used as an  indication of total dissolved solids.  This is a simple measure-

ment, and one which gives immediate  results.  It is absolutely necessary,

however, to obtain a correlation between the two indicator analyses for

the particular land disposal site being monitored.


1  I
     AMMO A//A
                                  cguea&L ANALYSES
                                           01 u
                                    N I
                                                              i *. L_
                                                       «]   I o-V*»

  This  chapter will provide guidelines for selecting  indicators as well as

  scheduling and data management and interpretation resulting in a repre-

  sentative,  valid  and cost/effective monitoring  program.  The emphasis of

  this  chapter is on passive monitoring  which  Chapter 4 defined as the

  sampling of monitoring  devices,  strategically located in reference to

  ground-water flow directions,  at regular intervals to determine chemical

  constituents  in the  ground water at that point  and time.  In addition,

  this chapter  assumes  that  the  landfill being monitored includes only
 normal municipal  solid waste.  Where special wastes are involved,  such

 as hazardous  chemical and  liquid wastes,  the indicator selection and

 sample   scheduling would  be modified accordingly, to be more waste specific.

 The presentation  in this chapter will be keyed into the fundamentals of

 leachate and the monitoring networks that were presented  in Chapter 3

 and 4, respectively.


 The background water quality at a land disposal  site must be considered  in

 selecting  the indicators for a monitoring program.  For  example, a ground

 water  with  a high  background iron content would  certainly lessen the

 value  of iron as a leachate indicator,  because it  will require higher

 concentrations of  iron to differentiate from  background.  In a given land-

 fill situation,  it is necessary to obtain adequate background data in order

 to  draw reliable conclusions regarding  possible  leachate contamination.

Therefore,  consideration must be  given  to both the ground-water quality

which occurs   in nature,  as well  as  other possible sources of contamina-

tion which may affect  the background quality.

Reliable data on background quality of ground water can be of critical

importance relative to regulatory and legal considerations.


All ground water contains chemical constituents in solution.  The kinds

and amounts of constituents depend upon the geologic environment, movement,

and source of the ground water.  Typically, concentrations of dissolved

constituents in ground water exceed those in surface waters.  This is

particularly true in arid regions where recharge rates are low.

Dissolved constituents are primarily derived from minerals in contact with

ground water and percolating water going to ground-water recharge.  Common

chemical constituents of ground water include:

              Cations                 Anions             Undissociated

              Calcium                 Carbonate          Silica

              Magnesium               Bicarbonate

              Sodium                  Sulfate

              Potassium               Chloride


Table 6-1 lists relative abundances of these and other chemical constituents

in natural ground water.  Minor and trace constituents are present selectively

depending upon the mineralogy of the region.   Analyses of ground water

samples enriched in silica, iron, calcium, and sodium are given in Table

6-2.  These elements are frequently enriched in ground water.  Brines and

thermal spring waters were not included in Table 6-2.

                                             si. A
                TABLE  6-1
                PORTABLE HATER'*'
Major Constituents  (1.0  to  1000 ppra)
      S                            Bicarbonate
Secondary  Constituents  (0.01 to 10.0 ppm)
      Jron   .   ,     ..              Carbonate
      Strontium                    Nitrate
      Potassium                    Fluoride
Minor Constituents  (0
                      001 to 0.1 ppm)
Trace Constituents (generally less than 0.0001 ppm)
     Beryllium                     r
     Bismuth ,
    (        )                      Silver
     Cesium                        Thallium
     Gallium                       Thorium
     Gold                          Tin
     Indium                        Tungsten
     Lanthanum                    '
     Platinum                      Zirconium

 Ground-water quality Is classified according to domestic  and industrial

 use on a simplified basis for convenience.   Salinity,  the concentration

 of total dissolved solids,  and hardness,  the combined  calcium and magnesium

 concentrations,  are classificatory criteria.  The  classification scheme

 is shown on Table 6-3.   Water with a high concentration of dissolved solids

 can build up scale in boilers, be  harmful to plants when  used for irrigation,

 and interfere with quality  of products  in manufacturing.   Hard water also

 builds up scale  deposits in boilers,  and  forms scums with soap in laundering.

 Within a large body of  ground water,  the  natural chemical composition tends

 to be  relatively consistent.   Variation of ground water with time is minor

 in comparison with surface-water quality  changes.

 Ground water under natural  conditions tends  to increase in salinity  with

 depth.   Most of  the geologic  formations in the United  States  are  underlain

 by brackish  to highly saline  waters.  Density  and permeability differences

 act to maintain  a  separation  between these waters and  the  overlying  fresh

 ground water.                                                        (


 It  should be  evident from this discussion that  ground-water composition can

 vary widely  under  natural conditions.  Man's activities add another dimension

 to  the  complexity  of  ground-water quality.  The effect on ground-water

 quality of point sources of contamination such as waste lagoons, acid mine

 spoils, and oil well brines are relatively easy to trace.   Diffuse sources

 of  contamination such as regions of septic tanks, irrigation, or farm

 chemical usage may affect bodies of ground water creating a chemical enrich-

ment which is relatively uniform.   Detection of point-source contamination

                     INMG/L UNLESS NOTED,
Silica (SI02)
Aluminum (Al)
Iron (Fe).
Calcium (Ca)
Magnesium (Mg)
Sodium (Na)
Potassium (K)
Carbonate (CO3)
Bicarbonate (HCO3>
Sulfate (SOJ
Chloride (CI)
Fluoride (F)
Nitrate (NOa)
Dissolved solids
Hardness as CaCO3
Specific condustance
umhos/cm @25
pH units
Temperature, °.C


'• —








                                                         D?"^   A  7"
Concentration of total dissolved solids
            ppm  n £.. IL .
Based on salinity
 Slightly saline
 Moderately saline
 Very saline
 Briny 4)

Based on hardness
Moderately hard
 Very hard 4).
         over 100,000

         over 35,000

      Hardness as CaCO ) ppm
         0-60        3
         over 180

 within a region of general contamination will require relatively higher

 concentrations of contaminants in comparison to comparable uncontaminated


 No estimate of background concentrations of leachate indicators  typical

 for a geohydrological setting could be used in lieu of actual measurements.

 The only way to ascertain the ground-water quality at a given site  is  to

 measure it.  However, man's activities, as previously mentioned,  can

 influence ground-water quality.  A description of contaminants associated

 with certain of these activities could be helpful as it would point out

 those indicators which need to be delineated from unnaturally high back-

 ground concentrations in order to trace leachte-enriched ground water.

 The  following sources of ground-water contamination are listed in Table 6-4

 which summarizes their potential contributions of ground-water contaminants.

 Their similarities  to and distinctions from leachate should be carefully

 noted so  that interferences will be  recognizable.

 Highway deicine  -  Over 6,567,000 tons (5,962,000 tonnes) of deicing salts

were  used nationwide  in 1966-7.        The most  common salt in use is

 sodium chloride,  with calcium chloride use amounting to  only 4 percent

 of that of  sodium chloride.

Open  storage  of  salt  or salt/sand mixtures may  result  in  leaching of salt

with  rainwater.   The  leachate after  reaching  ground  water, will form a

plume  of salt enriched  ground water  which could contaminate wells in the

vicinity.   On the other hand,  spreading of salt on the  road results in

a more diffuse  salt-enrichment of ground  water.  Wells  located near major

highways have been affected by deicing  salt.

Highway Leaky Septic .-
Indicator deicing sewers tanks Mining Irrigation
Calcium M
Sodium H
Chloride H
Other h.m.
Org N







Land dis- Petroleum Feed-
posal sludge expl & dev lots











H = High
M =
L = Low
P = Potential

  Leaky sewers  -  Sewer pipes which have been In service over a period of

  years are likely to be leaky.  Sewage gases form acids which dissolve

  concrete and mortar, usually the substance of older sewer pipes.   When

  the pipes are located In the unsaturated zone, raw sewage may leak and

  percolate to the ground water.

  Sewage  contains  some inorganic  salts, sulfur,  nitrogen,  trace metals,  and

  suspended and dissolved organic compounds.   Sulfur and nitrogen are

  generally present  as sulfide and  ammonia.   After  entering  the zone of

  aeration,  these  ions are  oxidized to  sulfate and  nitrate.  Thus, sulfate

  and nitrate  are  associated  with leaky sewers In Table  6-4.  The organic

 matter exerts a  large BOD and COD.  Enteric organisims, bacteria and viruses,

 are present  in large numbers creating a potential  for biological contamina-

 tion.  It has been estimated that approximately 500 million gallons of

 sewage is lost annually in  the U. S.  through leakage.  (2)

 Septic tanks  -  Contaminants carried to ground water in percolating septic

 tank effluent are similar to those from leaky sewers.  The major difference

 is  that  septic tanks have provided an opportunity for some anaerobic de-

 composition.   Thus,  MBAS and BOD levels are reduced from those of raw

 sewage.   Again, percolation  of effluent through the zone  of aeration

 converts  ammonium and sulfide to nitrate and sulfate.   A  reduction of

 dissolved oxygen  in  the  percolate  or ground  water  by a  high BOD flow  can

 cause dissolution of  iron, hence the iron rating in Table 6-4.

Unless the septic tank is  within a couple of feet of  the water  table,

bacterial contamination should not be  a problem.  However,  a septic tank

located in coarse-textured soil  overlying a  fractured rock  aquifer might

cause considerable bacterial and viral contamination.

Septic tanks in a density of one per acre or less are  not likely to

significantly influence regional ground-water quality.  As density in-

creases, these point sources of contamination blend together and result

in a general degradation of regional ground water.

Mining  -  A variety of contaminants are generated in leach-mining and

ore beneficiation which are specific to the mineral type and mine location.

Locations generating these contaminants would be obvious, so it is not

necessary to deal with them here.

A more  general contamination problem is generated by wastes from strip

and shaft mining particularly as these methods pertain to coal.  In strip

mining, overburden must be removed  to expose coal or  ore seams.  The  coal

is separated  from waste rock and is washed.  The wastes produced in these

processes are termed spoils and gob piles.

Frequently,  the waste  rock and  mineral  contains  pyrite  (FeS2),  an  iron

sulfide mineral.   When exposed  to air,  pyrite  oxidizes with the help  of

iron-oxidizing bacteria.   The  oxidation produces sulfuric acid  which  keeps

iron in solution and  frequently dissolves other  heavy metals from waste

minerals.   Drainage water from strip  mine spoils or from mine shafts  may

have a pH of less than 2.  This acid  mine drainage kills fish in surface

waters and produces a red-yellow scum that is unsightly.

The acid character of the spoils and gob piles prevents plants from covering

 them.  The resulting erosion continuously exposes new pyrite to oxidation.

 Millions of tons of sulfuric acid are introduced into the environment each

year from acid mine drainage.  Large regions of Pennsylvania, West

Virginia, Ohio, Indiana, and Illinois have been contaminated from

coal mining wastes.  Colorado has a similar problem from abandoned

metal ore mines.

Acid water can contaminate  ground water with a variety of heavy metals

which it dissolves.  Reduction of the ground-water pH also occurs creating

a more corrosive medium.   Iron and/or manganese accompanying acidic water

add a metallic taste to water and cause staining  of plumbing fixtures and

when it is used in  laundering.

Irrrigation   -  Ground or  surface water used  for  irrigation becomes more

mineralized as it percolates  through  soil and  dissolves mineral and

fertilizer constituents.   Irrigation  water going  to recharge carries  an

enrichment of some  or  all  of  theAionsJ  calcium, magnesium, sodium, potassium,

chloride, sulfate,  and nitrate.

Continued irrigation increasingly mineralizes ground  water.  This enrich-

ment may become  limiting to further ground water  use.   In California, there

are closed basins where  ground water  has  been recycled  by irrigation  and

has become  so mineralized it is approaching the limit of  usefulness.

Land disposal of  sludge   -  The literature on sludge  chemistry has reported

all of  the  indicators listed in Table 6.4 as being present in one sample

or another.   Concentrations range from parts per billion to percentages.

Sludge  is  applied to  the land surface.  Therefore, its  influence on ground-

water  quality is determined by the transport of  its constituents through the

 soil  and underlying unsaturated zone.  The contribution of landfill  leachate

indicators to ground water is calculated on the basis of sludge leachate

having undergone reactions in the soil and unsaturated zone.

Ammonium in sludge will nitrify and the portion that leaches  will move

as nitrate.  Most of the heavy metals and phosphate will probably be

retained in the soil and be in extremely low concentrations in percolate.

Bacteria have been studied after sludge application to land.   Fecal coli-

forms exhibit a die-off rate which reduces their number to a negligible

population in a matter of 2-3 weeks.  Movement through soil is usually

no more than a few c«n-fcr«oaW$.  Viruses have been shown to be more in

soil, but are not likely to be a serious contaminant if digested sludge is


Petroleum exploration and development  -  Brines are almost universally

associated with oil deposits.  They are sometimes produced in greater

quantities than crude oil especially from older fields.  Brine pits are

the most common waste disposal facilities.   In  theory, water evaporates

leaving salt accumulations.   In  practice, frequently brine leaks from  the

pit and carries high concentrations of  salt  into underlying aquifers.

Sodium and calcium  are  the most  common  cations, with  chloride, sulfate,

and nitrate  4X5- the most  common  anions.   Some brine  contains enough

bromide for  economic recovery.   Brine may also  be used  as a secondary

recovery  injectant.  As an indication of  the extent  of  the problem, over
400 billion  gallons of  brine were  produced  in  the U.  S.  in 1974.

Feedlots   -   Ground-water contamination from feedlots occurs principally

from  leaching of  nitrate.  Some  mineralization of  infiltrating water  may

also  occur,  but not usually  to an  extent that  serious contamination results.

Phosphate is a serious pollution hazard to surface water from feedlot

runoff.  However, phosphate is retained in soil and doesn't usually

move into ground water.  Of the heavy metals, zinc is present in the

highest concentration in manure.  None of the heavy metals are in con-

centrations as high as those  associated with municipal sludges of mixed

domestic and industrial origin.  Ho appreciable contribution of manure

contained heavy metals to  ground water is anticipated.

There are a couple of sources of ground-water contamination for which it

is difficult to assign specific chemical constituents.  Waste lagoons

and oxidation ponds is one of these categories  (Table 6.5).  Such

facilities may contain almost anything of an  inorganic or organic type

imagined.  Therefore, in  listing leachate indicators, probabilities are

given of their occurrence  in  lagooned and ponded  waste leakage as it

enters  the ground-water system.

Buried  pipelines  and  tanks are another source of  ground-water contamina-

tion.   Probably  the most  common contaminants  from these sources are

petroleum products.   Chemical storage  tanks have  also been documented as

contributors of  contamininants to  ground water.   Again, the  probabilities

shown  in Table  6.5  represent  the probabilities  of the given  indicator

actually reaching ground-water.

                                                   DH68^   jfiV  F^ M^AM
                                                   RAF  8
Waste Iag6ons
and ponds
Buried pipelines
and tanks
Other h.m.
 I = Highly probable
 II = Probable
III = Unlikely

                                TABLE 6-6

                           LEACHATE INDICATORS

Oxidation-Reduction Potential
Conductivity                                              PHYSICAL
Chemical Oxygen Demand (COD)                              CHEMICAL
Total Organic Carbon (TOG)
Volatile Acids                                            Organic
Tannins, Lignins
Ether Soluble (oil & grease)
Organic Functional Groups As Required
Chlorinated Hydrocarbons
Total Bicarbonate Solids (TSS, TDS)
Volatile Solids
Alkalinity and Acidity
Nitrite-N                                                 Inorganic
Ammon ia—N
Heavy Metals (Pb, Cu, Ni, Cr, Zn, Cd, Fe, Mn, Si, Hg,As,  Se,  Ba, Ag)
Biochemical Oxygen Demand  (BOD)                           BIOLOGICAL
Coliform Bacteria (Total,  fecal; fecal streptococcus)
Standard Plate Count


A comprehensive listing of leachate indicator parameters has been prepared

and presented in Table 6.6.  This listing is based on the composition of

leachate which was presented in Chapter 3 and reflects the most widely

used leachate indicators by researchers in the field and state regulatory


The schematic diagram on Figure 6-1 and the list of leachate indicator

parameters in Table 6-6 represent the principle undesirable characteristics

of leachate from MSW.  Its deleterious effects an ground and surface waters

become apparent.  Just some of the effects include:

       1.   Soluble organics and some inorganics causing dissolved

            oxygen depletion in surface waters.

       2.   Soluble constituents that result in objectionable tastes

            and odors in water supplies.

       3.   The obvious health hazards connected with toxic materials

            and heavy metal ions and microbiological contaminants in

            excess of drinking water standards.

       4.   The effects of dissolved solids in excess concentrations

            limiting the use of ground and surface waters, for drinking

            domestic, industrial or recreational use.

These examples all point to the basic need for monitoring many of these para-

meters.  The reader is referred to the EPA Handbook for Monitoring Industrial

Wastewater * ' and to the introductory remarks in Standard Methods ^ '  for

further discussion and background information regarding the undesirable nature

and potential effects of the various leachate indicator parameters.

  The actual selection and use of indicators for a particular monitoring
  program will generally be de^i from the indicators on Table 6-6 and
  will depend upon a number of considerations.
        1.    Type of Monitoring Network - I, II or III as was
              presented in Chapter 4.
        2.    Susceptability to attenuation.
        3.    Background  water quality.
        4.    Location of well being sampled  -  "A"  Wells,  "B"  Wells,
              or  "C"  Wells.
        5.     Purpose of  Monitoring.
        6.    Other considerations including  cost,regulatory standards
             to be met,  availability of laboratory equipment and man-
             power,  simplicity and precision of determination.
        7.    Type of refuse handled and other site-specific factors.


 Indicators can be categorized into various groups  or levels of monitoring which
 vary in degrees  of information obtained in relationship to the purpose  for
 the monitoring.   Three such levels  widely used by  researchers,  engineers and
 regulatory agencies  are:
           .  Specific Conductance Measurements
           .  Key  Indicator Analyses
           .  Extended Indicator Analyses


For monitoring ground-water quality and its fluctuations over a period of
time, specific conductance is a useful parameter for approximating the total

amount of inorganic dissolved solids.  The real value of specific conduc-
tance is that it can be performed easily and quickly, requiring little
training, with portable field equipment which is relatively inexpensive,
accurate and reliable (approximately $200.00).

Specific conductance has been successfully correlated with total dissolved
solids for monitoring leachate-enriched ground water.  It also has been used
successfully to detect fluctuations and trends for ionic impurities in the
ground water.  If conductivity is being used as an indicator of total
dissolved solids, it is absolutely essential that a correlation be obtained
for the specific land disposal site being monitored.  Otherwise, gross errors
can be expected in data interpretation.

Availability of a conductivity meter at a site would allow an operator to
"spot check" monitoring wells at very frequent intervals (say weekly or monthly)
It can also be used advantageously during the sampling of a site to prioritize
wells to be sampled, where time and budget restrictions are a problem.


The intent of this monitoring group is to include highly sensitive analytical
parameters, which can be performed rapidly and accurately, at relatively
low cost, by personnel of minimum training, to yield reliable, useful data.
One should select a group of parameters which will provide information
regarding ionic, nonionic, inorganic, organic and suspended constituents of
the ground-water sample.  Most of the parameters should lend themselves to
field analysis using portable equipment.  Field analyses have the obvious
advantage of eliminating the necessity for low temperature and/or chemical
preservation of the sample, therby minimizing labor and deterioration effects
on the analysis which can result from sample degradation due to aging.  This


  monitoring  group can be  performed  at  frequent intervals, with low cost,
  manpower and equipment requirements.

  The final selection of analytical parameters must consider the background
  water quality, the pure leachate quality, as well as the hydrogeologic
  influences.   The group must therefore be site specific  as well as  remain
  flexible to  change at a site as may be dictated  by data interpretation.

  For discussion purposes,  the following list of key indicators  has been
  widely used  in the  field  to determine  the presence of  leachate:
            .  Specific  Conductance
            .  pH
            .  Temperature
           .  Chloride
           .  Iron
           .  Color
           . Turbidity
           . COD

 This group fits well the criteria for key indicators and, with  the exception
 of  COD, can be  performed rapidly using portable field equipment.

 It  is not suggested  that all of the indicator parameters mentioned in this
 list  must necessarily  be used together  to determine the presence  of  leachate.
 Rather,  this  is  to be  left to the judgment  of the  individual analyst.  It
 is  possible,  for instance,  that results from just one of the analyses (i.e.
 specific  conductance)  could  indicate the  probable presence of leachate.   A
decision  would then be made  whether  to  run some or  all  of the remaining
parameters, or additonal tests  to  determine  the reason  for the high conduc-
tance value.

Data obtained from indicator analyses have value in and of themselves, that

is, individual determinations will give valuable information regarding the

possible presence of leachate.  In addition, data obtained from several

indicator analyses can be crosu-correlated and interpreted so that even more

insight can be gained about the nature of the contamination, over and above

what is obtained from the individual tests.

The following hypothetical examples serve to illustrate this point:

Example 1.   A sample of ground water is analyzed and yields the

             following results:

                High levels of color and COD.

                Low levels of iron, turbidity, and conductance.

                   These results could be interpreted as an indication of

             the presence of an appreciable concentration of colored  organic

             contamination in a system which is  low  in soluble and suspended

             inorganic contaminant levels.

Example 2.   A sample of ground water is anlayzed and yields the

             following results:

                High levels of conductance, chloride, pH, and  turbidity.

                Low levels of COD, color, and  iron.

                   These results  could be interpreted as  an indication  of

             the  presence  of  an appreciable concentration of inorganic

             materials, both  suspended and  in  solution  and  a low  concen-

             tration level of organic materials.

  Kxamplc 3.   A sample of ground water is analyzed and yields the
               following results:
                  High levels of conductance, chloride, iron,  color,  and  COD.
                  Low levels of turbidity and pH.
                     These results could be interpreted as  an  indication  of
               the presence of appreciable concentrations of both  inorganic
               and organic contaminants in acid solution and very  low levels
               of  suspended materials.

 Further interpretation of the indicator data must  then consider background
 water quality, hydrogeology,  attenuation and other pollution sources in the
 vicinity of the  landfill in order  to  determine whether the presence of  leachate
 is indicated.
 Th«snonitoring group is a much more comprehensive group of analytical para-
 meters.  Table 6-6 presents a comprehensive extended indicator analyses
 Croup which provides for a good characterization of the water samnle and
 represents indicators commonly used by researchers and required by r.,any
 regulatory agencies. (4)  Performance of this monitoring group will obviously
 he  costly,  requiring trained personnel and an adequately equipped sanitary
 laboraboty.   Very few of the parar-.eters can be analyzed with  portable  field
 equipment  thus  requiring the utilization of acceptable  storage and preser-
 vation  techniques.

 There can be  a  number of reasons  for performing extended indicator analyses.
The main reason is  the  need  to perform additional analyses as  a result of
problems which become known  fron data.  provided  by the key indicator analyses

Additional testing, whether Instituted by a regulatory agency or the landfill

operator, should always be approached conservatively from both a technical

and cost standpoint.  Arbitrarily requiring an extended program without

reasonable technical justification results in a very costly undertaking with

little or no regard to its cost benefit effecitveness.

An extended analysis program can only be justified when it can be demonstrated

that a basic indicator program does not have the necessary and sufficient

capability to assure the absence of leachate contamination or to provide

enough information to solve a specific contamination problem or yield required

background quality information.  When background quality information is being

developed, a relatively large number of analytical parameters should be

investigated In order to choose the few most valuable ones which will consti-

tute the key indicator analysis program.

A sudden radical change in a key indicator may also point to the necessity

for extended analytical work.  For example, indicator data might suddenly

indicate contamination by a non-specific organic material, as indicated by

an elevated COD value.  In this case, the indication would be to perform a

number of analyses, such as wet chemical tests or even infra-red and gas

chromatography (if equipment Is available), :r .  in order to determine which

specific compound or compounds caused the change In the COD.  From a

regulatory standpoint, the nature of an extended analysis program would also

be related to the standards which have been set to assure the absence of

leachate contamination,'  For example, suppose that a state regulatory agency

decides to adopt as its enforcement standard the U. S. Public Health Service

Drinking Water Standards of 1962.  This would result in an extended analysis

  program which would at least require testing for twenty-four  parameters,

  four physical and twenty chemical.

  As  another example, suppose that a state regulatory agency decides to adopt

  as  its  enforcement standards a series of seven physical and chemical para-

  meters,  (i.e.   -  PH,  specific conductance,  chemical oxygen demand (COD),

  chloride,  iron,  color  and turbidity).   This  program would per se constitute

  an  adequate key  indicator program,  thereby eliminating the need for an ex-

  tended analysis  program for regulatory  purposes.

 Thus, it can be  seen that the  concept of an  extended  analysis program is a

 relative one.  It  is usually relative to regulatory requirements,  or  the need

 for data, in addition to  the key  indicatbr program or  specific contamination

 problems.  It must, therefore, be the task of  the responsible engineers  and

 analysts to determine what will  constitute an 'extended analysis  program, if

 any, for a given landfill site.


 For  a given land disposal site, the selection and use of  indicators will vary

 with the  background water quality, the differential attenuation  that, may occur

 and  the well being monitored.

 6.5.1      BACKGROUND WATER QUALITY MONITORING     New Land  Disposal Site

 For  a new  land disposal site,  the background  monitoring will define the natur-

 ally occurring constituents in  the ground water and  contaminants from other

 possible pollution  sources that may  be in  the area.   Section 6.2 presents a

good summary of the background  quality one might  expect to find in"different

geologic settings and with a variety of  "other  pollution sources."  Usually,


the background quality at a new site can be satisfactorily defined by per-

forming an extended indicator analysis group on an "A" well(s) that has

been installed at the site for this purpose.  Section 4.2 discusses various

types of "A" wells in the different monitoring networks.  It may be desirable

to have additional "A" wells if other pollution sources that may have a

significant impact on the ground-water quality at the site are suspected

where there is  more'than one water-bearing zone to be monitored.

For the first sampling, the extended indicator analyses group should include,

as a minimum,  all of the parameters on Table 6-6.  Additional parameters

may be deemed desirable where applicable to define "other pollution sources"

in the area.  In the case of the latter, the characteristics of other pollution

sources should be investigated in selecting any additional parameters for

monitoring.  It is desirable to perform a few samplings (say 3 or 4) to ob-

tain a more statistically reliable data base for the long-term monitoring

prior to commencement of operations.  As is usually the case, this is not

done due to time and economic considerations.  Therefore, it is suggested

to at least collect additional data on a few selected key indicators which

will likely be used in the long-term monitoring.  These can be done quickly

and cheaply and will provide valuable data in developing a statistically

reliable data profile  (see Section 6.6).

While the "A" wells will establish the background water quality for the site,

it is also important to develop background quality data for each  "B" and  "C"

well.  This is more  important for larger landfills where the "A", "B", and

"C" wells are relatively far apart in respect to changes in geology and

other pollution sources which may influence their quality.  Therefore, it is

 recommended that an extended indicator analysis group be performed on

 all monitoring wells as soon as possible after their installation.    Existing Land Disposal Site

 For an existing land disposal site, where solid waste has already been

 landfilled, the background quality monitoring should include leachate

 contamination that may have already occurred on the site.  Monitoring in

 this case must then involve the "A", "B", and "C" wells installed at  the site,

 where as before the "A" well will define the natural background  quality,

 while the "B" and "C" wells define existing leachate contamination.

 Here, the quality of the "B" well becomes especially significant in selecting

 the key and extended indicators for the monitoring program.   This well will

 detect the leachate contaminants that are entering the saturated zone.  The

 analysis of this well will also provide valuable  information about the unknown

 past history of a site.   For example, an old site may have  disposed of hazard-

 ous wastes in the past which could result in significant  concentrations of

 exotic contaminants not normally attributed to  municipal  solid waste  (i.e.

 certain heavy metals or pesticides).   Depending upon the  extent  of the problem

 and the degree of potential hazard to the public,  a decision can then be

 made  as to whether to include additional parameters into  the monitoring

 program as key or extended indicators.   In  any  event,  analysis of  the "B"

well  will represent the  "worst  case"  in terras of  leachate contamination at

 a particular  site,  and can provide a  basis  for  including  or  excluding  in-

 dicator parameters.


The on-going monitoring  program should  consist  of  the  judicious  use of repre-

sentative key and extended indicator analyses groups, the former being

run at more frequent intervals and the latter less frequently for verifi-

cation purposes.  The key indicator group is designed for the primary

purpose of determining presence or absence of leachate contamination and as

a "check" on quality fluctuations.  The extended indicator group is designed

to provide verification of non-specific key indicators (i.e. COD or specific

conductance) and for legal purposes in an enforcement action.

The on-going program will, of course, involve the monitoring of the "A",

"B" and "C" wells.  After establishing some background quality data for

the various wells (whether it be one or a series of samplings), the most

representative indicators for the site should be selected.  In doing this,

one must consider the background quality data, the constituents of the

leachate, and the potential influence of attenuation.  The information

presented In Chapter 3 on attenuation, and In Chapter 6 on background water

quality provides some valuable guidelines for selecting indicators.

As an example, suppose the natural background quality is high in iron or

total dissolved solids.  In this case, the value of iron and specific con-

ductance as key indicators of leachate contamination is lessened because

of the high concentrations that would be required to distinguish from back-

ground.  Or, there may be another pollution source in the vicinity that is

affecting the background quality of the ground water, such as deicing of

adjacent highways, or local septic tanks, or leaky sewers.  These, too, might

serve to lessen the value of various parameters as leachate indicators.

Section 6.2.1 presents some very useful information on background water

quality which should be used as a guide in indicator selection.

Susceptibility  to attenuation  in different  soils would also affect the

value of the various parameters as  indicators of leachate.  The information

presented in Section 3.2 and Table  3-2  can  be used as a guide in indicator

selection for a particular disposal site.   Table 3-2 points out the sig-

nificance of chloride as an indicator due to its freedom from attenuation.

The key indicator program should be followed as long as no presence of

leachate is detected or where  leachate  is already present, no significant

fluctuations in the data are observed.  Another consideration here might

also be the regulatory agency's requirements, as many states do require a

periodic (say,  annual) testing for  an extended analysis group, regardless

of the monitoring trends being observed.  In most cases, all "A", "B", and

"C" wells at the site should be.included in the key indicator program.

However, this is not to be considered an ironclad rule of thumb.  Many

large acreage land disposal sites may have  as many as 20 monitoring wells.

In these cases, one may elect  not to sample all 20 wells at.each sampling,

but to rotate sampling to include say 5 wells each sampling date.  Therefore,

in the case of  quarterly sampling,  each well would be sampled once per year.

In this case, each sampling should  include  at least one of each well type,

that is, an "A", "B", and "C"  well.

The convenience of the specific conductance test can be a valuable asset

in this case.   Ability to be  tested quickly, with a field instrument may

allow at least  a specific conductance reading on all 20 wells at each sampling

date.  The need to pump out  the well prior  to sampling would limit the use

of the specific conductance  given  time  restrictions.  The specific conductance

reading provides the added dimension of deciding on the spot which wells

should receive  priority for  sampling.   Having the specific conductance data

iirofilc on hand for quick reference,  the field technician  can  compare  today's

reading "ith the profile which may show a significant change and worthy  of

further investigation.  So, a combination of a routine rotational  sampling

sc-herlule, subject to possible modification due to a significant rh.mgb In

specific conductance, would comprise a sound rationale to the  use of the

key indicator group.

If a significant change is observed in a key indicator parameter or parameters

(i.e. -  increase in specific conductance), the possibility of leachate contamina-

tion should be suspected and a plan for further investigative and corrective

action  should be instituted immediately.  This plan  should include additional

sampling and analytical work as determined by  the  key indicator data  obtained,

to serve as a  data base  for developing a  satisfactory correction action  to

eliminate the  cause  of  the contamination  problem and to nonitor the effect

of implementing the  same.

Assuming that  a leachate contamination problem has been  discovered  by the

key  indicator  program and corrective action iinplenented,  sampling and indicator

 testing should be instituted on an increased level of frequency,  with the

 possible inclusion of additional parameters.  This should be  continued until

 there is reasonable certitude that conditions have returned  to normal and  will

 probably remain so.  At this point, a re-assessnent of the key indicator

 analytical program should be made.  It should then be decided whether to re-

 institute the program in its original form or to  initiate it in a modified

 form, based unon experience gained in solving the contamination problem.

 The following example will serve  to illustrate this approach:

    Suppose that sulfate was found to  be  a principal contributing

    contaminant which had  caused  a high specific conductance  reading.

   It might then be decided  to  test for sulfate, for a limited time,

   in addition to the other  parameters of the key indicator program.

   Valuable data could be collected in  this manner to show sulfate/

   conductance ratios which  could be used as a guide in monitoring for

   future problems.

Obtaining background quality data and further investigating a particular problem

aie the principal technical reasons for implementing an extended indicator

analyses group.  In the le&al sense, enforcement data needs may require extended

indicator analyses data.  Administratively, many regulatory agencies will re-

quire (say, annual or bi-annual) gStwipJarM for an extended indicator analyses


In any case, the conservative use of the extended indicator parameters should

be kept in mind due to the relatively excessive cost and manpower requirements

associated with their performance.  The fact that the extended indicator

parameters are basically serving to verify  the results of the key indicator

parameters, should provide a basis of a rationale for selecting and ranking

the former.  In other words, a  significant  fluctuation in a particular key

indicator would warrant further investigation by a select group of extended

parameters and not automatically the entire extended indicator analyses group.

The implementation of the extended indicator analyses group should be a

monitoring well specific decision.  For example, a quality change in one "C"

well should not immediately  require the testing for extended indicators in

all of the "C" wells.

The following examples of relationships between key and extended indicators

serve to illustrate the point  :

1.         Specific Conductance;

          A significant change in specific conductance would be an

          indicator of possible chances in levels of one or more of

          the following extended indicator parameters:  pll, total

          dissolved solids, chloride, sulfate, phosphate, alkalinity,

          acidity, nitrogen series, sodium, potassium, calcium, mag-

          nesium, hardness, heavy metals, cyanide, fluoride, and COD.

2.         A sionifleant change in chloride concentration would be an

          indicator of possible changes in levels of one or more of

          the following extended indicator parameters:  specific con-

          ductance, total dissolved solids, pH, acidity, and metal ions.

3.         A significant change in iron (total) concentration would be

          an indicator of possible changes in levels of one or more of

          the following extended indicator parameters':  specific conduc-

          tance, pH, total dissolved solids, chloride, sulfate, phosphate,

          manganese, and fluoride.

4.         A significant change in color would be an indicator of possible

          changes in levels of one or more of the following extended in-

          dicator parameters:  COD, TOC,  tannins, lignins, organic N,

          total dissolved solids, pH, iron, BOD and conductance.

5.        A significant change in  turbidity would be  an  indicator of possible

          changes in levels of one or more of the following extended indicator

          parameters:  pH, conductance,  COD, TOC, tannins,  lignins,  total

          suspended soilds, phosphate, alkalinity,  acidity, calcium, mag-

          nesium, hardness, heavy netals,  fluoride,   and BOD.

6-        A  significant  change  in COD would be an,indicator of possible

          changes  in  levels  of  one or more of the ^following extended

          parameters:  HOD,  pH,  conductance, TOG, volatile acids,

          tannins,  lignins,  organic-N,  total dissolved solids, total

          suspended solids,  volatile solids.

In a practical situation,  several of the key indicators will nost probably
show variations at  the sane  time.  Therefore, looking at combinations of key

indicators will provide  additional information for the analyst to define

the chemistry of the  system  involved and further assist him in specifying

additional extended indicators  for analysis.


The sampling schedule for  a  land disposal site should maintain flexibility

for modification.  Monitoring frequency is greatly influenced by many factors

as listed,below:

1.    Characteristics of ground-water flow.

2.    Location and purpose of the particular monitoring well.

3.    Climatological  characteristics.

A.    Trends in the monitoring  data.

5.    Local and institutional data needs.

6.    Other considerations.

Obviously, the hazardous nature of the  leachate and what is being threatened

(i.e. a single domestic  well versus an  entire municipal water supply) will

to a large degree dicatate the monitoring effort.


The principal characteristic of concern in selecting a sampling frequency

is the rate of ground-water flow at the land disposal site.  As was dis-

cussed in Chapter 4, the flow rate will be primarily dependent on the

aquifer porosity, permeability as well as the hydraulic gradient existing

at the site.  The aquifers were generally categorized by porosity into

intergranular porosity, fracture porosity, and solution porosity with

ground-water flow rates ranging in orders of magnitude from a few feet

per year in an impervious intergranular porosity aquifer to tens of

feet  per day in  the more unpredictable fracture and  solution porosity


The higher  the rate of ground-water  flow, warrants more frequent monitoring.

Two extreme examples would  be  an intergranular porosity aquifer with

impervious  clay  soils and a fracture or  solution porosity  aquifer with

unpredictable and high flow rates  likely.   For  an  example,  suppose  the

closest  "C" well is  100  feet from  the landfill and  the closest downgradient

property line or domestic well is  300 feet  away.  At the  site with the  clay

soils, it would  be  senseless to frequent sampling  if, theoretically,  it

would take  ten  to  twenty years for any leachate-enriched  ground water to

 even reach  the  well.   Here, after  establishing background quality, an annual

 or bi-annual monitoring of the well with select  key indicator parameters

 would suffice.   In the latter case, however, it  is possible that contaminants

 could migrate off of the property in a matter of weeks or months.  Here,

 a quarterly monitoring with key indicators, with,  perhaps, a more frequentfd^,)

 spot checking with specific conductance would be warranted.  As was discussed

 earlier in the Chapter, the extended indicator group would be  utilized as needed,

Most  landfills  will fall between these two extremes,  but one can see that

careful  consideration must be given to the flow rate  and the distances

involved to  select  a frequency which will  not  miss an environmental

occurrence.                                    '

In a  similar sense,  the  monitoring well would be influenced by the vertical

flow  rate of leachate-enriched ground water.  For example, suppose a disposal

site  is  underlain by a sand aquifer with  a relatively high ground-water flow

rate, but it is separated from the landfill by  a thick layer of impervious

clay.  Here,  a  concentrated monitoring effort of the  "C" wells in the

aquifer  would not be justified until the  "B" well detected that contaminants

have  travelled  through the clay layer and reached the aquifer.


The distance  that a  monitoring well is located  from the land disposal site

and its  depth will  influence monitoring frequency.  For example, there may

be a  case where a line of "C" wells are placed  along  the property line for

legal and administrative reasons due to ground-water  protection laws.

There is  little need to  concentrate on monitoring these wells until the

monitoring results of closer "C" wells presents  some  reason to believe

that  leachate contaminants may be  approaching close to the property line.

Only minimum  monitoring  of these wells to establish background quality and

meet regulatory requirements would be justified.   Anything more than an

annual frequency would be considered wasteful.

Another  example might be a well located in deep  water bearing zones separated

from the disposal site by other aquifers  and aquicludes.  Chapter 4 depicts

examples of this (i.e. coastal plain)  where there are a series  of  alternating

aquifers and aquicludes.  For institutional reasons, or regional water planning

purposes, a monitoring well may be placed in a deep aquifer which  has almost

no chance of being contaminated by the land disposal site.   After  an initial

sampling, or, perhaps, two for background purposes, such wells would only

deserve attention every two or five years, or, of course, in the unlikely

event that other monitoring results cause reason for concern.


Jn setting up the initial monitoring schedule for a particular site, one

should analyze  the fluctuations in leachate generation that occur over the

year.  The water balance method, which was presented  in Chapters  3 and 5,

is a very useful tool for  this purpose.  As an example, suppose it is

desired  to perform quarterly  sampling.   Instead  of arbitrarily assigning

a sampling date every third month, most  of the monitoring  effort  should

be concentrated either during and/or  after those periods of  the year of

greatest leachate generation. The  reflection  of  the  actual sampling  dates

should  also  take into account the  well  location  and  depth, ground-water

flow  rate,  saturation condition of the  landfill, and other factors  to

project approximate  log times that may  occur  between first appearance of

leachate and its  impact on the monitoring well.


The  three factors  presented above (ground-water  flow rate, well purpose

and  location and  clinate) will be used  in establishing monitoring frequencies

 at  the outset.   However, monitoring frequencies should never be considered

 ironclad, but should maintain flexibility for modification to respond to

fronds in the monitoring data.

As .in example, suppose a spot check with a specific conductance meter indicates

a significant change in the water quality at a particular well.  Further

investigation with additional key and extended indicators would be desired

immediately, regardless of when  the next sampling is scheduled.  Concentrating

on this well might also reduce the frequency at another well whose recent

data has not shown  significant  changes in water quality.


Monitoring frequencies at a site may also be altered for legal and institutional
                            J»                ,

reasons.  As an example, suppose an enforcement action is initiated against

a landfill.  In order to strengthen their case, attorneys for both the state

and the disposal site may request that, all of the monitoring wells be monitored

for an extended indicator analyses group.


Other reasons for modifying the  monitoring frequencies at a site would include,

          . complaints from neighboring residents.

          . an unusually severe  climatological event, such as a

            hurricane with large amounts of rain in a short time


          . a sudden change in or addition of an "other pollution

            source", such as an  oil spill adjacent to the property.

          . an unusual operational occurrence, such as the illegal

            and/or improper dumping of a large volume of liquids at

            a site*

A properly planned monitoring program will allow for modification in sampling

schedules to respond to  the above-mentioned occurrences.


In selecting indicator parameters and sampling frequencies,  it is important

to be mindful of relative costs for performing the monitoring.  The three

basic levels of indicators used for monitoring presented earlier, vary not

only in the depth of analytical data provided but also in the costs for

sampling and analysis.

Specific conductance is so valuable because it is so inexpensive to perform.

Being analyzed with a portable field meter, the analytical cost  is merely

the  few extra minutes required by  the  technician  to do the test  at the site.

The  meter,  itself,  is relatively inexpensive, cost approximately $200.00

 (1976 prices).  The sampling costs are also low primarily because  it  is not

necessary  to collect  and  preserve  samples for the laboratory  thus  lessening

 the  amount of bottles to  be  carried  and the time  for  adding  sample preserva-

 tives.  This  advantage would be somewhat lessened where pre-pumping  of  the

wells  is?  done.   There is  no  way  of estimating sampling costs and time require-

 ments  since they are site specific depending  upon accessibility and  number

 of wells,  as well as the pre-pumping (If necessary),  and sample withdrawal

 method used.  For order of magnitude comparison purposes only, a typical

 commercial laboratory would charge approximately $3.00 per sample for a

 specific conductance analysis (New York Area, 1976 prices).

 A typical key indicator analysis  group  (i.e.  specific conductance, PH, tempera-

 ture, chloride,iron, color,  turbidity, and COD) would be more expensive for

 sampling and analysis.  Like specific conductance, all  the others, except

 COD, can be run  in the field with portable equipment.   Sampling time will

 be  increased by  the  additional equipment and analyses required, the  time  to

 collect,  store and preserve the COD sample.  Where one  man  could  manage nicely

 with specific conductance measurements, an assistant may be desirable

 in monitoring  for the key indicators depending upon the number  and

 accessibility of wells to be sampled and the sample withdrawal awl hod

 used.   Adverse weather conditions may also necessitate  transporting  '

 samples back to the laboratory for analyses, where specific conductance

 could  still  be done in the field.  For order of magnitude comparison

 purposes,  a  typical commercial laboratory would charge  approximately

 $50.00 per sample for the key indicator analyses listed (New York Area,

 1976 prices),  exclusive of sampling.

 A  typical  extended indicator analysis group, such as listed  in'Table 6-6,

 would  be the most expensive level of  monitoring for both  sampling and

 analysis.  With  the exception of  some key indicators which might be run

 in  the  field,  all  the indicators  require proper storage,  preservation-and

 transport  of samples  to the laboratory for'analysis.  This will require

 additional sampling time and possibly additional manpower to perform

properly and efficiently in the field.   Of course,  adverse weather conditions

may further  complicate  sampling efforts.

                                 TABLE 6-7

                          COMPARATIVE COSTS OF

                            INDICATOR ANALYSES*
Monitoring Group
Specific Conductance
Approximate Cost of Analysis +
    Per Sample  ($)	

           $ 3.00
Key Indicators
Extended Indicators
Mote;    It should be noted that  there  is an economy of numbers relative

to both  sampling and analysis.   Appreciable quantity discounts are  usually

available for  different  levels of  sampling and  analysis.  Additional

savings  can  usually be realized  through the use of  long-term sampling  and

analysis contract.

    * A comparison  of sampling costs has not been made  due to its extreme
      site specificity -  such a comparison  should consider the number  and
      accessibility of wells, weather conditions, whether or not  the wells
      will be pre-pumped  prior to sampling,  and  the  pre-pumping and  sample
      withdrawal methods  uses.

    + Based  on January  1976 rates of a typical commercial laboratory in
      the New York Area.   Refer to Chapter  3 for laboratory manpower re-
      quirements for analyses.

Again,  for  order  of  magnitude comparison  purposes,  a  typical commercial

laboratory  would  charge approximately  $600.00-$700.00 per sample for the

extended  indicator parameters listed in Table  6-6,  exclusive of sampling.

Table 6-7 summarizes the cost of analysis for  the various monitoring groups

discussed above.  As noted,  no comparisons of  sampling costs has been

made due  to its extreme site specificity.  In  general terms, however, the

sampling  costs do increase  as more  indicators  are added and that the sampling

cost increases are magnified if pre-pumping of the  wells is performed.


6.8.1     GENERAL

In a given  sanitary  landfill, appreciable quantities  of data relative to

ground-water quality will be generated  over a  period  of time.  Several

factors govern the amount of data produced among which are the number of

monitoring  wells, the number of parameters to  be tested and the frequency

of testing, both  scheduled  and unscheduled (response  to operational problems).

As a hypothetical case,  let  us assume  that there are  20 monitoring wells in

a given landfill  and that the following tests  are performed in a given year:

Testing Category      No. of Parameters   No.  of Wells   No. of Tests

Annual-Extended               30                20            600

Quarterly-Indicator           10                20            600  (200 x 3)

Problem-Unscheduled           30                20            6QQ

                                                Total     1,800

The total number  of  tests performed in  the landfill over a period of one year

will be 1,800.  This figure could approach 20,000 over a 10-year period.

This amount of raw data must be processed, interrelated, statistically

analyzed amd stored in readily retrievable form so that it will be of

maximum value for quality control, engineering and legal purposes.

The use of digital computer treatment would appear to be an excellent tool,

both rapid and cost-effective as a management information system in the

handling of this type of data.  Other approaches to data management could

entail manual processing, storage and retrieval of the data in the form of

tables, charts and graphs which can show parameter levels and trends

relative to standard values.  In both cases, the statistical handling and

use of analytical data for quality control purposes, in the form of ranges,

means, standard deviations, parameter ratios and control charts will be


The technological state of the art of land disposal is still relatively

young and is highly dependent on monitoring for its development.  Even if a

particular design operational strategy is successful at one site, it cannot

be automatically assumed acceptable for all sites due to the extreme site

specificity which is fundamental to land disposal of solid waste.  Again,

monitoring becomes critically important.  Thus, the parameters monitored

and the significant results obtained from the monitoring program will be

critically evaluated in assessing a site and related design and operational

approaches and in deciding upon modification.  Because of  the significance

which may be placed on the results of the monitoring program, it  should be

the desire of the landfill management to understand and attempt to identify

the causes of fluctuations in monitoring data obtained.    Incorrect  inter-

pretation  of  monitoring results may result  in  unnecessary expenditures

or  in  a  false sense  of  security.

The variability  of the  indicator parameters measured  in a monitoring program

may result from  various phenomena,  some  of  which  are  listed below:

1.         Natural fluctuations in the background  water quality.

2.         Occurrence of another pollution source  which might cause

           the background water quality to fluctuate.

3.         Attenuation taking place  in the subsurface  environment.
                                                                  ,   ;

4.         Climatological variations.

5.         Operational deficiencies,  incidents  and modifications.

6.         Experimental  errors in the  analyses  of  measured parameters.

7.         Sampling method  utilized.

Variations in the background water  quality  will occur with location and time.

Such variations  recorded in  the "A" wells should  be fingerprinted statistically

to allow for  more accurate interpretation of the  data fluctuations recorded

at the "B" and "C" wells.  In the same vein, fluctuations in background

quality may be aritficially  induced by another pollution source.  As was

stressed earlier, such  occurrences  must  be  carefully  recorded because of their

effect on  monitoring data  interpretation.   As  was discussed in Chapter 3,

attenuation and  Climatological variations will have a definite influence

on time and distance changes in monitoring  data.

Operational factors  will have a definite influence on the monitoring data

and its evaluation and  should be carefully  documented.  For example,

operation  changes, such as,  type of wastes, a  sudden  disposal of a large

quantity of liquid wastes, a deficiency  in  cover, or  construction of the dikes,

diversionditches and the like,  could all significantly affect  monitoring

results and should be carefully described with dates recorded.

The results of the analysis of  a sample, by the same or different technicians,

using the same laboratory techniques often fluctuate widely.   Even very

accurate laboratory analysis cannot prevent a relatively wide  range in

determined values of parameters,such as BOD, which may experience experi-

mental error as high as *20%.  Variations will also exist with alternate

analytical methods, especially  field versus laboratory methods.  This becomes

even more significant for concentrated leachate samples.  Where interferences

further complicate analysis.  All of this information must be  carefully

recorded because of its significance in data interpretation.   A more

detailed discussion on analytical methods is presented in Chapter 8.

Differences in the sampling method utilized will be important  for monitoring

data evaluation due to the variations that can be created.  Was the well

flushed out prior to obtaining a sample?  Was the sample collected aerobically

or anaerobically?  Was the sample properly preserved?  How much time elapsed

between sample collection,*analysis?  Who did the sampling?  It is important

to know all of this information and understand   /TS implications in

evaluating the monitoring results.

All of these possible causes in variations should be carefully recorded and

identified for proper evaluation of the monitoring  results.   It will be

important for the monitoring program to distinguish between fluctuations

which are significant and attributable  to the landfill  thus requiring some

form of remedial action versus  those variations which are insignificant or

not attributable to deficiencies at the landfill.   Of course, a complicating

feature for a  land disposal  site, unlike in water and air pollution, is

the time lag which inherently exists between cause and effect.  For example,

it may take months or years  for  a fluctuation observed in an "A" or "B"

well to reach  a distant  "C"  well thus often complicating and retarding

data interpretation.


In the Handbook  for Monitoring  Industrial Wastewater. USEPA, 1973,

the value of statistics  in monitoring is discussed:

"Statistics aid in the development of general laws resulting from numerous
individual determinations which, by themselves, may be meaningless.  The
resulting relationships  are  part of the fundamental function of statistics
which expresses the data obtained from an investigative process in a con-
densed and meaningful form.  Thus, the average or mean is often used as a
single value to represent a group of data.  The variability of the group of
observations is expressed by the value of the standard deviation and trends
in concentrations during the monitoring process are expressed in the form
of regression  coefficients.

In general, the concern  is with  the treatment of the collected data.  The
accuracy oA. usefulness of these  data is greatly enchanced if a full under-
standing was involved in generating the facts.  The balance between use of
statistical methods and  evaluation based upon physical understanding is
extremely important.  The use and value of statistics decreases as physical
understanding  increases.  Specifically, the difficulty lies in separating
chance effects from valid occurrences.  With the knowledge of basic pro-
bability theory and the  use  of statistical techniques, such as Least Squares
Curve Fitting, Analysis  of Variance, Regressive and Correlation Analysis,
Chi-Squared Goodness of  Fit, and others, it is possible to construct mathe-
matical models and curves of almost any level of precision desired.  Such
techniques help to evaluate  information having wide variations, so that
an estimate of the best  value of the parameter being measured can be assigned;
and also to assess the precision of that estimate.  Statistical procedures
may also help  in identifying errors and mistakes and are helpful in comparing
sampling methods and procedures  and in evaluating waste loadings from different
process schemes."

Evaluation based upon physical understanding is especially significant for

monitoring of  n land disposal site due to the extreme site specificity of the

various phenomena involved.

Probably, the major use of statistics in a monitoring program is to

i-orrol;itu thu data for the proper choice of statistical parnraeLer.s (me.-m,

range and standard deviation) for the specific indicators for evaluation

and comparison purposes.

Statistics and data analyses are very broad topics and are beyond the

scope of this manual.  The above-referenced EPA Handbook^ ' cited  several

good references on statistics and these have been included in the bibliography

at the end of this chapter for additional reading where a statistical approach

is desired.   It should be emphasized that rules and formulas for data

analyses are many and they must be chosen wisely and applied correctly to

be of value.


Once a monitoring program has been in operation for an appreciable period

of time, the data obtained from it can be used to provide specific analytical

profiles for ground water and/or surface water for a given landfill site.

These profiles will be characterized by data from a number of sampling points

within the landfill and will reflect the influence of the various phenomena

which were discussed earlier that result in fluctuations in the indicator

parameters.  Statistical analyses of the profiles will provide such important

statistical values as normal ranges, means and standard deviations for each

of the indicator parameters.

Quality control data of the landfill site can be obtained from the profile

data.  This could take the form of control charts for the various parameters

which would indicate whether the operation was "in control" or "out of control

relative to upper and lower control limits provided by the control chart.

SL.-illsl I»:s  «':in  pLay  nn  Important  rolo  In  tho. correlation of specific

parameters, especially  in  the  case  of  specific  conductance to other

parameters  such as total dissolved  solids.   Reference  5 presents an

excellent discussion on the  statistics for  correlation of specific

parameters.  The  data profile  will  also provide an  insight into the inter-

relationships of  the various key  indicator  parameters  in the form of normal

ratios  (i.e. conductance,  total dissolved solids, iron, color, etc.)

which should be developed  for  a cost effective  monitoring program.  When

enough data are obtained on  indicator  parameter ratios (i.e. conductance,

total dissolved solids, etc.)  for a given landfill  site, statistical values

of range, mean  and standard  deviation  can be developed, as is done for the

individual  indicator parameters themselves.   This information can be used

as a valuable statistical  tool for  quality  control  of  the landfill and as

an aid in the diagnosis of leachate contamination problems and their probable


An indicator program, based  on sufficient background quality data and on-

going statistical information,  should  provide a basic, cost-effective, reliable

monitoring  tool for  the quality control of  a landfill.

In a monitoring program, data  profiles can  be used  in a variety of ways, some

of which are discussed  below:

-I-        Concentration of the various indicator parameters versus time

          for each monitoring  well.

          This  is perhaps  the  most  common use of a  data profile in moni-

          toring  programs.   It provides an  immediate visual picture of the

          trends  in  quality  and is  nicely defined with the basjc statistical

          values  (mean, range  and standard  deviation).  It provides a

          valuable tool in comparing monitoring results of the "A",

          "B" and "C" wells for operational and enforcement purposes.

          It provides a readily available and convenient tool for

          comparing water quality trends to trends and occurrences in

          the various phenomena that influence the ground-water quality

          which were discussed earlier in this section.

2.        Concentration of the various indicator parameters versus

          distance from the landfill.  This type of profile would be

          constructed by plotting the data for selected indicator

          parameters which are obtained on a particular date for the

          various "C" wells located at different distances from the

          landfill.  The quality of the "B" well would represent the

          concentration at zero distance from the landfill.  Chapter 3

          (Section 3.2.4) discussed the use of this type of profile in

          the measurement of attenuation at a land disposal site.  Figure

          3-1 shows an example of this profile.

3.        Other profiles providing "physical understanding" information.

          In the evaluation of the monitoring data obtained at a land

          disposal site, it would be of value to be readily accessible to

          information on the phenomena which may be the potential cause

          of fluctuations and trends in the monitoring data.  This might

          include a water balance profile and a "chronological events"

          profile of important occurrences.  A water balance profile, such

          as shown in Figure 6-2 could be developed for each site as part

          of the permit applications or for several representative "typical

          sites" throughout the state.  The actual quantities are not as

 important as the trends they would depict.   A profile  of

 "chronological events" might look like  Figure 6-3  and

 could  be  kept  on file and up-to-date  easily by the inspec-

 tion and  monitoring personnel.   Reference to such  a profile

 would  be  of  obvious value providing physical understanding

 in evaluating  monitoring  results.  It should be recognized,

 however,  that  one must  be mindful  of the time  lag  between

 cause  and effect that is  inherent  at land disposal sites,

when using such profiles  in  the evaluation  of monitoring


                                                                                                               Si A* SIMSA

                           CHAPTER 6 - REFERENCES

 1.    Field, Richard,  E.J.  Strugeski,  11.E. Masters, and others.
       1975.  Water pollution  and associated effects from street
       salting.  Pages  317-340 in W.J.  Jernell and Rita Swan, eds.
       Water pollution  control in low density areas.  University
       Press of New England, Hanover,  New Hampshire.

 2.    Roux, Paul H. 1975.   Personal communication.  Geraghty &
       Miller, Inc., Port Washington,  New York.

 3.    MacCallum, Douglas R. 1975.   Personal communication.  Geraghty
       & Miller, Inc., Port Washington, New York.

 4.    Chian & DeWalle, 1975,  Compilation of Methodology for Measuring
       Pollution Parameters of Landfill Leachate, University of Illinois
       USEPA, Cincinnati, Ohio.

 5.    Handbook for Monitoring Industrial Wastewater, U.S.  Environmental
       Protection Agency, Technology Transfer,  August 1973.

 6.    Standard Methods for the Examaination of Water and Wastewater,
       13th Edition,  American Public Health Association,  1970.

                            ADDITIONAL READING

 1.     Handbook  for Analytical Quality Control  in Water and  Wastewater
       Laboratories,  EPA,  Technology Transfer,  1972.

 2.     Eckenfelder, W.W.,  Industrial Water  Pollution  Control, McGraw-Hill
       Book Co.,  1966.

 3.     Eckenfelder, W.W.,  Water Quality Engineering for Practicing Engineers,
       Barnes & Noble,  Inc.,  New York,  1970.

4.     Neville, A.M. and J.  B.  Kennedy,  Basic Statistical Methods for Engineers
       and  Scientists,  4th Printing, International Textbook  Co., Scranton,
       Pennsylvania, 19700

5.     Standard Methods  for  the Examination of Water and Wastewater, 13th
       Edition, American Public Health  Association, 1970.

6.    Velz, J.C.C., "Graphical Approach to Statistics", Water and Sewage
      Works, 1950.

                               CHAPTER 7



The sampling  of ground and surface waters associated with sanitary  landfill

monitoring is a critically important operation.  The analytical results

obtained from the samples and the subsequent decisions which are based on

the analytical data, are vitally dependent upon the validity of the samples


Every effort  must be made to assure that the sample is representative of the

particular body of water being sampled.  A detailed sampling plan,  acceptable

to all interested parties, should be developed prior to any sampling operations.

The physical, chemical and bacteriological integrity of the sample  must be

maintained from the time of sampling to the  time of testing in order to keep

any changes at a minimum.  The time between  sampling and testing should be

kept at the absolute minimum which is practicable.


The following, from  ^Standard Methods    p. 36, is a useful guide:

          "A record should be made of every  sample  collected and every
          bottle should be identified, preferably by attaching an
          appropriately inscribed tag or label.  The record should
          contain  sufficient information to  provide positive identi-
          fication of  the sample at a later  date, as well as the
          name of  the  sample collector, the  date, hour and exact


           location,  the water  temperature,  and any data which may
           be  needed  in the  future for  correlation, such as weather
           conditions, water level,  stream flow, or the like.  Sam-
           pling  points should  be  fixed by detailed description,
           by  maps, or with  the aid  of  stakes, buoys or landmarks
           in  such a  manner  as  to  permit their identification by
           other  persons without reliance upon memory or personal
           guidance	Samples from wells should be
           collected  only after the  well has been pumped for a
           sufficient time to insure that the sample will represent
           the ground water  which  feeds the well.  Sometimes it will
           be  necessary to pump at a specified rate to achieve a
           characteristic drawdown,  if  this  determines the zones from
           which  the  well is supplied.   It may be desirable to record
           the pumping rate  and the  drawdown as part of the sample
The quality of water pumped  should  equal approximately 3 to 5 well volumes.

If the well is pumped dry, sufficient  time should be allowed for full recovery

prior to sampling.


Various water withdrawal techniques were discussed in Chapter 5 including

vacuum pressure and bailing  methods.   The important underlying principle,

of course, being to obtain a representative sample of the ground water and

to minimize degradation.  If the well  depth is within pumpable limits, a

vacuum sampling technique can be used  to obtain the sample under anaerobic

conditions.  Figure 7-1 shows a typical vacuum sampling technique using a

vacuum pump and portable generator, used successfully in Orange County,

Florida.       Vacuum can also be supplied from an automobile or truck

engine or a hand pump manifold which could replace the vacuum pump/portable

generator combination.  Note in Figure 7-1, a 1/2-inch tube is permanently

installed in the monitoring  well which would eliminate the possibility of

cross-contamination between  wells.

                  COARSE BUILDERS SAND
                                             .010 WIDTH
                               WELL  SCREEN  SLOTS
    FIGURE  7-1  Profile  Of Shallow  Sampling  Well.(REF.  1)

With a pressure-type sampling method,  such as  the type shown on Figure 24

(Chapter 5),  the  sample  is obtained  by connecting the sample! bottle directly

to the 1/2-inch water discharge  outlet.  To  insure anaerobic conditions, the

sample bottle  should be  flushed  out  with an  inert gas prior to collecting a

sample.  The built-in feature of this  method,  being used to both pre-pump

and sample  the well can  effect considerable  savings on labor and also

eliminate the  possibility of cross-contamination between wells, as can occur

with portable  pumping and sampling devices.  They are also of notable value

in obtaining bacteriological samples where external sources of contamination

must be avoided.

Bailers are also  used to collect a sample.   A  Kemmerer water bottle sampler,

as shown on Figure 7-2  is a bailer commonly  used.  In transferring the sample

from the sampler  to the  sample bottle, contact with air and agitation of the

sample should  be  minimized slow  and  careful  transfer, placing the tip of

the sampler's  exit tube  to the side  of the sample bottle is recommended.

To minimize cross-contamination,  the  bailers  should be thoroughly flushed

out with tap  vater&with  the  first sample  from  the next well to be sampled

prior to collecting the  sample for analysis.

Samples for bacteriological  examination must be collected in sterile containers.

Detailed sampling procedures  for bacteriological samples are given in   Stan-

dard Methods ,  13th Ed., pp.  657-660 and   Biological Analysis of Water and

Wastewater ,  AM 302, Millipore Corp.,  1974,  pp. 4-6.

Samples can be taken directly  from wells  with  a sterile bottle in a weighted

frame which can be  lowered below the water surface and opened below surface.

Samples can also be obtained by  means of  various pumping devices, as described

f:  !

                     ch— chain which anchon upper valve to upper interior guide
                     «Jh— rubber drain tube.
                     dt— bras* drain lube.
                     «— interior guide fastened to inner surface of umplcr
                     h— rubber lube.
                     j— jaw of release.
                     js— j«w spring.
                     I* — lower valve.
                     m — messenger.
                     o — opening interior of drain lube.
                     P— pinch cocV .

                                              ""* °n hon'"ntl1 Pin- «« "d of »«cl> Hi. into groove on central rod

                                              "'""' f "^ "' Openlil" in "°°v                            -
                                                                                                                                                irfi*. i
                     uv— upper valve.
                     £f/'— View of complete samp'tr with »aI»-« open.
                         ««*/— Another type of construction of upper valve and tripping device
                        /om «jAr-Anoir,er t)F- of eon«rue:,on oflo^er vj|.e and driin tube. '

                                    FIG. 4 Sho.jnt Strurtur»l rc.ruro of Modifiri Kfmrvfrf r Simpler."
                                                                         C. S. Welch, LlmnotoficotMrthoib, p 200. Fig S9
                                                    FIGURE  7-2

 previously.  The same pumping schedule should be observed  as  for non-sterile

 samples.   Sample volumes of approximately 250 ml.  are usually satisfactory

 for  bacteriological testing.

 Sampling  and preservation of samples are addressed in the  1973  Annual Book

 of ASTM Standards.  Part  23,  Water;  Atmospheric Analysis, pp.  72-75, Standard

 Methods of  Sampling Homogeneous  Industrial  Waste Water; and pp.  76-91, Stan-

 dard Methods  of  Sampling Water.

 7.2.2     RECORDS

Adequate records should  be maintained on each  sample  that is taken.   Record

information should  include:

   Sample description:   Type  (ground water, surface water)  volume.

   Sample source:  Well  number, location.

   Sampler's Identity:   Chain of evidence should be maintained;  each  time

   transfer of a sample occurs a record including signatures of  parties

   involved in transfer should be made.   This procedure can have legal

   significance .

   Time and  date of  sampling.

   Significant weather conditions.

   Sample  laboratory number.

  Pertinent well data:   Depth, depth to  water surface, pumping schedule

  and method.

  Sampling  method:   Vacuum,  Kemmerer, pressure.

  Preservatives,if any:   Type and number -  i.e. HaOH  for cyanide,  H3PO

  and CuSO^ for  phenols,  etc.

    Sample containers:   Type,  size  and  number  -  i.e. -  three  (3)  liter

    glass stoppered  bottles, one  (1)  one  gallon  screw-cap bottle,  etc.

    Reason for sampling:   Initial sampling  of  new  landfill;   annual sampling,

    quarterly sampling,  special problem sampling,  in conjunction with con-

    taminant  discovered  in nearby domestic  well.

    Appearance of  sample:  Color, turbidity, sediment,  oil on surface.

    Any  other information  which appears to  be  significant:  i.e.   sampled

    in conjunction with  state, county,  local regulatory authorities.

    Sampled for specific conductance  value  only.

    Sampled for key  indicator  analysis.

    Sampled for extended analysis.

    Re-sampled following engineering  corrective  action.

    Name  and  location of laboratory performing analyses.

    Sample temperature upon sampling.

    Thermal preservation:  i.e. - transportation in ice chest.

    Analytical determinations, if any,  preformed in the field at the time

    of sampling and  results obtained, analysts identity and affiliation.


For most samples  and analytical parameters, either glass or  plastic containers

are satisfactory.   Some exceptions are encountered, such as  the use of

plastic for silica  determinations and  glass for phenols, or oil and grease

determination.  Containers should be kept  full until samples are analyzed,

in order to maintain anaerobic conditions.

As a general  guide  in choosing a container for a sample, the ideal material

of construction should be non-reactive with the sample and especially, the

particular analytical  parameter to be tested.  Table  2  lists the recommended

containers for various analyses.

Cleanliness of containers  is  of utmost importance.  An  effective procedure

for cleaning  containers is to wash sequentially with  a  detergent, tap water

rinse, nitric acid  rinse,  tap water rinse, hydrochloric acid rinse, tap

water rinse and  finally, deionized or distilled water.  In addition, the

containers should be rinsed several times with the sample at the time of



The following excerpt  from Methods for Chemical Analysis of Water and Waste.

EPA-625/6-74-003, pp.  vi-xii,  is a useful guide for sample preservation,

sample volume requirements and sample containers.

Additional useful information relative to preservation  of polluted waters,

wastewaters, etc.,  is  available in Standard Methods.  13th Ed., 1971, pp. 368-


Additionally, Standard Methods provides a very useful "Sampling and Storage"

section for many of the analytical methods offered.


Samples should be preserved at low temperatures during  transport to the

laboratory for analysis.   A convenient method is to use an insulated cooler

containing ice so that a temperature of 0 to 10°C is  maintained.

If possible, appropriate chemical  preservation should be performed in the

field for various analytical parameters at the time of sampling.  In this

case, separate bottles and chemical preservatives are required for particular

parameters.  As an example, for the extended analyses group in Chapter 6,

proper preservation techniques would require splitting the sample into as

many as approximately ten (10) bottles.  Thus, one can see that sampling

a large number of wells for several analyses can become a cumbersome procedure

in the field for this reason.

Regardless of the method of preservation, analyses should be performed as

soon as is practicably possible after sampling.

                              SAMPLE PRESERVATION
Complete  and unequivocal  preservation  of  samples,  cither domestic sewage,  industrial
wastes, or natural waters, is a practical impossibility. Regardless of the nature of the sample,
complete stability for every  constituent can  never be achieved.  At best,  preservation
techniques can  only retard  the chemical  and biological changes that  inevitably  continue
after the sample is removed from the parent source. The changes that take place in a sample
are either chemical or biological. In the former case, certain changes occur in the chemical
structure of the constituents that are a function of physical conditions. Metal cations may
precipitate as hydroxides or form complexes with other constituents;cations or anions may
change valence states under certain reducing or oxidizing conditions; other constituents may
dissolve or volatilize  with the passage of time. Metal cations may also adsorb onto surfaces
(glass, plastic, quartz,  etc.). such as, iron and lead. Biological changes taking place in  a
sample may  change the valence of an element or a radical to a different valence. Soluble
constituents  may be  converted to organically bound materials in cell structures, or cell lysis
may  result in release  of cellular  material into solution.  The well known  nitrogen and
phosphorus cycles are examples of biological influence on sample composition.

Methods of  preservation are relatively  limited and are intended  generally  to (1) retard
biological  action,  (2) retard hydrolysis of chemical compounds  and complexes and (3)
reduce volatility of constituents.

Preservation  methods are generally limited to pH control, chemical addition, refrigeration,
and freezing. Table 1 shows the various preservatives that maybe used to retard changes in

 Alkali (NaOH)
          TABLE 1


Bacterial Inhibitor
Metals solvent, pre-
vents precipitation

Bacterial Inhibitor
Salt formation with
organic bases

Salt formation with
volatile compounds

Bacterial Inhibitor
   Applicable to:

Nitrogen forms,
Phosphorus forms

Organic samples
(COD, oil & grease
organic carbon)

Ammonia, amines
Cyanides, organic

organic materials,
BOD, color, odor,
organic P, organic
N» carbon, etc.,
biological organism
(coliform, etc.)
In summary, refrigeration at temperatures near freezing or below is the best preservation
technique available, but it is not applicable to all types of samples.

The recommended choice of preservatives for various constituents is given in Table 1. These
choices are based on the accompanying references and  on information supolied by various
Regional Analytical Quality Control Coordinators.


                     TABLE 2

Chlorine Req.
- 50
P, G«>
Cool, 4°C
Cool, 4°C •
HNO3 to pH <2
Cool, 4°C
Cool, 4°C
H2SO< topH<2
None Req.
Cool, 4°C
Cool, 4° C
Cool, 4°C
24 Hrs.
24 Hrs.
6 Hrs.<3)
24 Hrs.
7 Days
7 Days
24 His.
24 Hrs.
24 Hrs.
                          NaOHtopH 12
Dissolved Oxygen

 • Winkler
300    G only     Det. on site
          300    G only    Fi.\ on site
                                           No Holding
                                  No Holding

TABLE 2 (Continued)
Measurement (ml) Container Preservative
Fluoride 300 P, G Cool,4°C
Hardness 100 P, G Cool,4°C
Iodide 100 P, G Cool,4°C
MBAS 250 P, G Cool, 4° C
Dissolved 200 P, G Filter on site
-HN03 topH<2
Suspended -'* Filter on site
Total 100 HNO3topH<2
Dissolved 100 P, G Filter
HNO3 to pK <2

Total 100 P, G HNO3 to pH <2

7 Days
7 Days
24 Mrs.

6 Mos.
6 Mos.
6 Mos.
38 Days
13 Days
38 Days
1 3 Days

TABLE 2 (Continued)
Measurement (ml)
Ammonia 400

Kjeldahl 500

Nitrate 100

Nitrite 50
NTA ... SO
Oil & Grease 1000

Organic Carbon 25

pH 25

Phenolics 500

.phosphate, 50
Container Preservative

P, G Cool, 4°C
H2SO4 topH<2
P, G Cool, 4°C
HiSO4 topH<2
P, G Cool, 4°C
H,SO4 topH<2
P, G Cool, 4°C
P, G Cool. 4°C
G only Cool, 4°C
H,S04 topH<2
P, G Cool, 4°C '
• H2 SO« to pH <2
P, G Cool, 4°C
DeL on site
G only Cool, 4°C
H3P04 iopH<4

P, G Filter on site
Cool. 4°C




24Hrs. <«)
24 Mrs.





                              TABLE 2 (Continued)






Container Preservative
P, G Cool, 4°C
HjSO4 topH<2
P, G . Cool, 4°C

P, G Filter on site
Cool, 4°C

P, G Cool, 4°C

P, G Cool, 4°C
P, G Cool, 4°C
P, G Cool, 4°C

24Hrs. C«>

24 Hrs.<4>

7 Days

7 Days
7 Daya
Settleable Matter     1000    P, G
                   None Req.



 50     P, G        HNO3 to pH <2       6 Mos.
 50     Ponly      Cool, 4° C
100    P,G
 50     P, G
Coo!, 4°C

Cool, 4°C
                     7 Days
 7 Days

                                TABLE 2 (Continued)
Container  Preservative
  50     P,G
           2 ml zinc
  50     P,G
1000     P,G
           Cool, 4°C
           Det. on site
No Holding

 200     G only     Cool, 4°C
 100     P.G
           Cool, 4°C
 7 Days
 1.   More specific instructions for preservation and sampling are found with each procedure
     as detailed  in 'this manual. A general discussion on  sampling water and  industrial
     wastewater may be found in ASTM, Part 23, p. 72-91  (1973).

 2.   Plastic or Glass

 3.   If samples cannot be returned to the laboratory in less than 6 hours and holding time
     exceeds this limit, the final reported data should indicate the actual holding time.

 4.   Mercuric chloride may be  used as an alternate preservative at a concentration of 40
     mg/1, especially if a longer holding time is required. However, the use  of mercuric
     chloride is discouraged whenever possible.

 5.   If the sample is stabilized by cooling, it  should be warmed to 25°C for reading, or
     temperature correction made and results reported at 25°C.

 6.   It has been shown that samples properly preserved may be held for extended periods
     beyond the recommended holding time.

                              CHAPTER 8

                         ANALYTICAL METHODS


 Reliable,  cost effective analytical methods  must  be  selected  and  applied  in

 order to successfully  carry  on Basic Indicator, and  Extended  Analysis  programs.

 The parameters of  interest in the  analytical characterizations  of leachate are

 usually  physical,  chemical and biological.   Normally,  the desired information

 is  quantitative rather  than  qualitative,  although qualitative data may be

 required at  times  for special problems.   For purposes  of this Manual,  consider-

 ation will be  given only to  the quantitative aspect  of the analytical data.

 As  stated previously,              "Leachate  represents an extremely complex

 system containing  soluble, insoluble,  organic, inorganic, ionic,  nonionic and

 bacteriological constituents  in an  aqueous medium.  Actual types,  numbers and

 levels of constituents are widely variable...."

 When  dealing with a complex material of variable  composition, such as

 leachate, it is recognized that there  is a serious potential  for numerous

 interferences in the determination  of  a given parameter.

The physical measurements, such as  specific  conductance and pH,  are not

normally subject to appreciable interference,but many of the chemical and

biological determinations are readily affected by matrix interferences.

When an analyst wishes  to  perform a quantitative  determination on a particular

parameter, he must  decide  which  analytical  method will be used.  There is

usually a choice among  several standard  methods which can be applied to a

given determination.  Among  the  many factors which must be considered in the

choice of an analytical method are the following:  sensitivity, precision and

accuracy required,  nature  of the matrix  and its effect upon the determination

(interferences), available equipment, manpower and instrumentation, level of

expertise of the analyst,  number of samples to be analyzed, turn-around time,

history and available information regarding the sample, reason for performing

the analysis, how the analytical data will  be offered other parameters, if

any, to be determined on the sample,  importance of cost factors.  When all

pertinent considerations of  this nature  have been carefully weighed  the

decision is then made to apply a particular standard method to the problem.

There are several literature sources of  standard  analytical methods which can

be applied, either  directly  or with modification, to the analysis of leachate

samples.  There are three  references which  are in wide use for this purpose,


1.   Standard Methods for  the Examination of Water and Wastewater. 13th Ed.

        APHA, 1971

2.   Manual of Methods  for Chemical Analysis of Water and Wastes, U. S.

        Environmental Protection Agency, 1974

3.   1973 Annual Book of ASTM Standards. Part 23, Water; Atmospheric


Some comments are made  relative  to the analysis of polluted waters and other

similar samples in  Standard  Methods for  the Examination of Water and Wastewater.

P. 367.  These comments, following,  are  appropriate to review at this point.

"These procedures described  in Part 200  of  this manual are intended for the

physical and chemical examination of wastewaters of both domestic  and indus-

trial origin, treatment plant effluents,  polluted waters, sludges  and bottom

sediments.  An effort has been made to present methods which apply as generally

as possible and to indicate modifications which are required for samples o£

unusual composition, such as certain industrial wastes.  However,  because of

the wide variety of industrial wastes, the procedures given here cannot cover

all possibilities and may not be suitable for all wastes and combination of

wastes.  Hence, some modification of a procedure may be necessary in specific

instances.  Whenever a procedure is modified, the nature of the modification

must be plainly stated in the report of results.  The procedures which are

indicated as being intended for the examination of sludges and bottom sediments

may not apply without modification to chemical sludges or slurries."

In this same vein, the following comments are made in Handbook for Analytical

Quality Control in Water and Wastewater Laboratories, U.S.E.P.A., 1973, P  1-3.

"Regardless of the analytical method used in the laboratory, the specific

methodology should be carefully documented.  In some water pollution reports

it is customary to state that Standard Methods have been used throughout.

Close examination indicates, however, that this is not  strictly true.   In  many

laboratories,  the standard method has been modified because of recent research

or personal preferences of the laboratory staff.   In other  cases, the standard

method has been replaced with a better one.  Statements  concerning the  methods

used in arriving at  laboratory data  should be  clearly  and honestly stated.

The methods used should be adequately referenced and  the procedures  applied

exactly as directed.

Knowing the  specific method which has been used,  the  reviewer can apply the

associated precision and accuracy of the method when  interpreting  the  labora-

tory results.  If  the analytical methodology is in doubt,  the data user may

honestly  inquire as  to  the  reliability of  the  result  he is  to interpret.


  The advantages of strict adherence to accepted methods should  not  stifle

  investigations leading to improvements in analytical procedures.   In  spite

  of  the value of accepted and documented methods,  occasions  do  arise when a

  procedure must be modified to eliminate unusual interference,  or to yield

  increased sensitivity.   When modification is necessary,  the revision  should

  be  carefully worked out to accomplish the desired result.   It  is advisable to

  assemble  data using both the regular  and the modified  procedure to show the

  superiority  of the latter.   This  useful information  can be  brought to the

  attention  of the  individuals and  groups responsible  for methods standard-

  ization.   For  maximum benefit,  the modified  procedure should be rewritten

 in the standard format  so  that  the substituted  procedure may be used through-

 out the laboratory  for  routine  examination of samples.  Responsibility for

 the use of a non-standard procedure rests with  the analyst and  his  supervisor,

 since such use represents a  departure from accepted practice."

 8.2    Alternate Analytical Methods

   8.2.1   Method Comparability

   Relative to the use of alternate analytical methods for the National Pollution

 Discharge  Elimination System, the EPA has published guidelines  in the  Federal

 Register,  October 16, 1973, as follows:

 "Typical Comparability  Testing Procedure.

 This procedure is  designed to provide  data on the  comparability(equivalency)

 of two  dissimilar  analytical methods  for measurement  of  the  same property or


 In regarding  the  comparison,  one method  is assumed to be satisfactory  (standard)

and the second  or  alternate  method is  compared for equivalency.

To provide  sufficient data  to apply statistical  measurements of significance,

the following determinations  are required:


1.    Using an effluent sample representative of  normal  operating

      processes, well mixed between aliquot withdrawal,  run  seven

      replicate determinations by each method.

Report values in the following manner:

                                 TABLE 1
Effluent Sample Representative of Normal Operating


Aliquot          Standard Method*            Alternate Method*

List 1 through 7

                            *Cite method reference

2.    If variations occur in the concentration of the measured

      constituent in the plant effluent, report the above testing

      on two more samples, one collected at f.he highest level of

      constituent normally encountered in the waste samples examined

      by the laboratory and one having a concentration at or near

      the lowest level usually examined.  Report values in the

      following manner:

                                TABLE 2

Effluent Samples of Varying Composition

Aliquot          Low Level                   High Level

List 1 through 7

3.    Using the sample from 1, add a small volume of standard solution

      sufficient to double the concentration.  Run 7 replicate determina-

      tions by each method.  Report values as Table 3:

Effluent Samples Plus Standard Solution, in the same way as Table 1.  Cite

source and amount of standard solution; it should be proportioned to the

  to the  original concentration.  The ahove procedure must  be  followed on each

  outfall for which a permit is issued,  unless it can be  shown that the outfalls

  in question are comparable."

 A comparability of that  procedure for analytical methods used on landfill leachate

  samples  can be  modelled after the above-cited  EPA  procedure.  Samples, instead

 of representing plant effluents, will  represent potentially  leachate-enriched

 ground and/or surface waters.  The results of  the  standard and alternate methods

 should be compared  for  statistically significant differences.  If the alternate

 method proves to be equal  to  or  better than  the standard method, it should be

 considered an acceptable analytical method for  the determination of the particular

 parameter in the leachate  sample.

    8.2.2   Other Analytical Methods

    A considerable amount of valuable pertinent  information on analytical method-

 ology and data is available in Standard Methods for the  Examination  of  Water

 and Wastewater.  13th Edition. 1971.  Several sections of this work are  reprinted

 here to  be used  as a guide in the analysis of leachate samples.  The particular

 subjects of  interest which are treated  are:

 1.     Other  (instrumental)  methods of analysis, including  Atomic

       Absorption Spectroscopy, FlamePhotometry, Emission Spectroscopy,

       Polarography,  Potentiometric Tiliation, Specific Ion Electrodes

       and  Probes,  Gas Chromotography and  Automated  Analytical Instrumentation.

       (pp. 12-15)

2.     Interferences  and  methods used for  their  elimination, (pp. 15-18)

3.     Expression of  Results,  (pp. 18-20)

4.     Siginficant Figures,  (pp. 20-21)

5.    Precision and Accuracy.  Statistical Approach, Standard Deviation,

      Range, Rejection of Experimental Data, Presentation of Precision

      and Accuracy Data, Quality Control.   (pp. 22-25)

6.    Graphical Representation of Data, Method of Least Squares.   (pp. 25-27)

7.    Self-Evaluation (Desirable Philosophy for the Analyst).   (p. 27)

8.    Methods Evaluation by the Committee on Standard Methods of the Water

      Pollution Control Federation.  (pp.369-370)

                 ff. '. i

an alkali, as is done in the direct nes-
slerization method for ammonia nitro-
gen.  For samples of relatively coarse
turbidity, centrifuging may suffice.  In
some instances, glass fiber niters, filter
paper or sintered-glass filters  of fine
porosity will  serve the purpose. For
very small particle sizes, the more re-
cently developed cellulose acetate mem-
brane filters may provide  the required
retentivcness.  Used  with  discretion,
each  of these methods will yield satis-
factory results in a  suitable situation.
However, it must be emphasized that
no single universally ideal method of
turbidity removal is available.  More-
over, the analyst should be perpetually
alert to adsorption losses possible with
any flocculating or filtering procedure
and an attendant alteration in the sam-
ple filtrate.

8. Other Methods of Analysis

   The use of an instrumental  method
of analysis not specifically described in
procedures in this manual is  permis-
sible, provided that the results so ob-
tained are checked periodically, either
against a standard method described in
 this manual or against a standard sam-
ple of undisputed composition.  Iden-
 tification of  any   such  instrumental
 method used must be included in  the
 laboratory report along with the analyt-
 ical results.
   a. Atomic absorption  spectroscopy:
 Atomic  absorption  spectrophotometry
 has been applied to the determination
 of a growing number of metals in drink-
 ing water without the need for prior
 concentration or extensive sample pre-
 treatment. The use of organic solvents
 coupled with oxjacetylene,  oxyhydro-
 gen  or nitrous  oxide-acetylene flames
 enables  the determination  of metals

which  form  refractory  oxides.  This
manual  presents  atomic   absorption
methods for  many metals.  Although
not  described  in the  text, calcium,
lithium, potassium, sodium and stron-
tium can also be determined readily by
the atomic absorption approach.
   b. Flame  photometry: Flame pho-
tometry is used for the determination of
sodium, potassium, lithium and stron-
tium.  To some extent it is also useful
for  the determination of calcium and
other ions.
   c. Emission spectroscopy: Arc-spark
emission spectroscopy is becoming  an
important  analytical  tool  for  water
analysis  and is proving valuable both
for  trace analysis and  for  certain  de-
terminations  not easily made  by any
other method. Considerable specialized
training and  experience with this tech-
nic  are required to  obtain  satisfactory
results, and  frequently it  is practical
to obtain only semiquantitative results
from such methods in water analysis. It
should be noted that an arc-spark emis-
sion spectrograph is relatively expen-
sive when used exclusively for routine
water testing,  but its purchase is jus-
tified  if it can be used as a  general
laboratory analytical instrument.
   Among the advantages of aic-spark
spectrographic  analyses are:  (1)   the
 minute size  of sample required;  (2)
 elimination of the necessity for bringing
 solids, such  as precipitates and corro-
 sion products,  into solution;  (3)  de-
 tection  of all  determinate elements
 present in a sample, whether specifically
 looked for or not; and (4) their unex-
 celled sensitivity for  some  elements
 Among the  disadvantages of spectro-
 graphic analyses arc:  (1) the hich cost
 of  first-class equipment; (2) the need
 for  special  training   and  experience;
 (3) the possible occurrence of scveio

TECHNIC/Other Method* of Analyiij

interferences which must be taken into
account if reasonable accuracy is to be
achieved; and (4) the inability  to dis-
tinguish between different valence states
of an element, as, for instance, between
chromic  and  chromate  or ferric and
   Silver  is the only clement for which
a spectrographic method is described in
this manual. The following can also be
determined  spectrographically:  alumi-
num, barium,  boron, chromium, cop-
per, iron, lead,  lithium,  magnesium,
manganese,  nickel, silicon,  strontium
and zinc.   Among  the  elements for
which there is no standard method in
this manual but which are dcterminable
by arc-spark spectrography are cobalt,
molybdenum, tin,  titanium, vanadium
and a number of others.1-2
   d. Polarography:  Polarography  is
suggested for scanning industrial wastes
for various  metal ions, especially where
the possible interferences in the precise
colorimetric procedures are unknown.
The  older  polarographic method for
dissolved oxygen also remains from the
   Recent  developments  in  polarogra-
phy include the introduction of pulse
polarographs  with  dual  synchronized
electrodes capable of differential deriva-
 tive  output.   Operation  in the  pulse
 mode permits determination of  seven
 or more metals on a single portion of
 the sample after ashing with nitric acid.
 If a 100-ml portion of the sample is
 ashed, determinations  may be made in
 the low microgram-per-liter range.
   A method closely allied to polarogra-
 phy is amperometric titration, which is
 suitable  for  the  determination of re-
 sidual  chlorine  and other  iodometric
 methods by titrimetry.
   e. Potentiomelric titration: Growing
 in acceptance for titrimetric work are
electrical instruments called titrimctcrs,
or electrotitrators.  If used  discreetly
with an understanding of their limita-
tions, these instruments can bs applied
to many of the titrimetric determina-
tions  described,  including  those  for
acidity and the alkalinities.  In addition,
titrimetric precipitation reactions such
as those for chloride, as well  as titri-
metric procedures based on complexo-
metric  and  oxidation-reduction  reac-
tions,  can  be performed with  these
instruments.  To be suitable for these
extensive applications, an  instrument
must be equipped with all the necessary
special electrodes. Some recent electro-
titrator models embody automatic fea-
tures by which a titration is self-execut-
ing after the preliminary settings  are
made. In order to avoid spurious read-
ings,  the  analyst  is  urged to check
instrument operation against represen-
 tative known samples in the same con-
centration range  as the water  under
   /. Specific ion electrodes and probes:
 The past decade has witnessed the ad-
vent  of specific ion  electrodes  and
 probes for the rapid estimation of cer-
 tain   constituents  in  water.   These
 electrodes function best in conjunction
 with  the  concurrently developed ex-
 panded-scale pH meters. For the most
 part, the new electrodes operate on the
 ion-exchange  principle.   The  specific
 ion electrodes available at this time are
 designed for the measurement of cal-
 cium, divalent copper, divalent hard-
 ness,  potassium, sodium, total mono-
 valent and  total  divalent cations, and
 bromide,  chloride,  cyanide,  fluoride.
 iodide,  nitrate, perchlorate  and sulfide
 anions  among others. Additional spe-
 cific ion  electrodes can  doubtless  be
 anticipated  in the future.
    These devices are subject to varying

degrees of interference from other ions
in the sample and must still receive the
thorough  study  that would  warrant
their adoption as tentative and standard
methods.  Nonetheless, their value for
monitoring activities is  readily  ap-
parent.  To remove all doubt of varia-
tions in reliability, each electrode should
be  checked in the  presence  of  inter-
ferences as well as 'the ion for which it
is intended.   This  manual details  the
electrode method for fluoride after a
collaborative   study  established  its
credibility in  the presence of common
interferences  (Section 121).
  The  commercial  dissolved oxygen
probes  vary  considerably  in  their  de-
pendability and  maintenance require-
ments.   Despite  these  shortcomings,
they have bsen applied to the monitor-
ing  of  dissolved  oxygen  levels  in a
variety   of waters  and  wastewaters.
Most  probes  embody  an  electrode
covered  by a thin  layer of electrolyte
held in place by an oxygen-permeable
membrane.  The oxygen  in solution
diffuses  through the membrane and
electrolyte layer  to react  at  the elec-
trode, inducing a current which is pro-
portional  to  the activity  (and  con-
centration) of the  dissolved  oxygen.
Satisfactory dissolved-oxygen electrodes
are also available without a membrane.
In either case, the face of the dissolved
oxygen  sensor  should  be kept  well
•agitated,  and temperature compensa-
tion should be provided,  in order  to in-
sure acceptable results in the laboratory
or monitoring application.
  g. Gas  chromatography:  Consider-
able work is under way in the develop-
ment of gas chromatographic methods
suitable for water and wastewater anal-
ysis.  Two such methods appear in
this manual: one for the determination

of chlorinated  hydrocarbon pesticides.
in drinking water; the second  for the
determination of  the components in
sludge digester gas. Investigations re-
veal that gas chromatography may also
be  useful  for  the determination  of
phenols. The skill of the operator and
the expense entailed in its purchase will
probably limit  use of this specialized
instrumentation  to the larger organiza-
tion which can afford the sizable finan-
cial outlay involved.
  h. Automated analytical instrumen-
tation:  Automated  analytical  instru-
ments are now available and in use to
run individual samples at rates of 10 to
60 samples per hour.  The same instru-
ments  can be  modified  to  perform
analyses for two to twelve constituents
simultaneously from one sample. The
instruments are  composed  of  a group
of interchangeable modules joined to-
gether in series by a tubing  system.
Each module performs the individual
operations  of filtering, heating, digest-
ing, time delay, color sensing, etc., that
the procedure requires.
  The read-out system employs sensing
elements with indicators, alarms and/or
recorders. For monitoring applications,
automatic   standardization-compensa-
tion, electrical and chemical, is done by
a self-adjusting  recorder when known
chemical standards are sent periodically
through the same analytical train.  Such
instrument systems are presently avail-
  Appropriate methodology is supplied
by the manufacturer  for many of the
common  constituents of  water and
waslewatcr.  Some methods arc based
on procedures described in this manual,
while other.":-originate from the manu-
facturer's  adaptation  of published re-
search.  Since a  number of methods of


 varying reliability may be available for
 a single constituent of water and waste-
 water, a critical appraisal of the method
 adopted is obviously mandatory.
   Automated methodology is suscepti-
 ble  to  the same  interferences as  the
 original method from which it  derives.
 For this  reason, new methods devel-
 oped for automated analysis must be
 subjected to the  exacting tests for  ac-
 curacy  and  freedom  from  adverse
 response  already met by the accepted
 standard  methods.
   Off color  and  turbidity  produced
 during the course of an analysts will be
 visible to an analyst manually perform-
 ing a given determination, and the re-
 sult will be properly discarded.  Such
 abnormal effects caused by unsuspected
 interferences might escape notice in an
 automated analysis.  Calibration of the
 instrument system  at least once each
 day with  standards containing inter-
 'ercnces of known concentration could
 ^elp to expose such difficulties. Routine
 practice is to check instrument action
 and guard against questionable results
 by  the  insertion  of  standards  and
 blanks  at regular  intervals—perhaps
 after  every 10 samples  in the train.
 Another important precaution is proper
 sample  identification by  arrangement
 into convenient groups.
  In brief, a fair degree  of operator
 skill  and  knowledge,  together  with
 adequately detailed instructions, is  re-
 quired for successful  automated  anal-
  /. Other newer methods of analysis:
Instrumentation and new  methods of
 analysis are always under development.
The analyst will find it to his advantage
to keep  abreast  of current  progress.
Reviews  of each  branch of analytical
chemistry  are  published  regularly in
the periodical, Analytical Chemistry.

9. Interferences

   Many analytical procedures are sub-
ject to  interference from substances
which may be present in the sample.
The more  common and obvious inter-
ferences are known, and information
about them has been given in the de-
tails of individual procedures. It is in-
evitable that the analyst will encounter
interferences about  which he  is  not
forewarned. Such occurrences are un-
avoidable because of the diverse nature
of  waters  and particularly  of waste-
waters. Therefore, the analyst must be
alert to the fact that hitherto untested
ions, new treatment compounds—espe-
cially  complexing  agents—and  new
industrial wastes constitute  an eve.--
present threat to the accuracy of cheni-
ical analyses. He must be on  his guard
at all times to detect the occurrence of
such interferences.
   Any sudden change in the apparent
composition of a supply which has been
rather constant, any off color observed
in a colorimetric test or during  a titra-
tion, any unexpected turbidity, odor or
other laboratory finding is  cause for
suspicion.  Such a  change may  be  due
to a normal variation in the relative
concentrations  of  the usual constit-
uents,  but  it may be  caused by  the
introduction of an unforeseen interfer-
ing substance.
   A few substances—such as chlorine,
chlorine dioxide, alum, iron salts,  sili-
cates, copper sulfate, ammonium  sul-
fate and polyphosphates—are so widely
used in water  treatment that they  de-
serve special mention as possible causes
of interference.  Of these, chlorine is

                                          ^- -       *• .-2S3frVx^i- - - -»-
                                          tj.i-.'  -*.  ->«PFS3F^~ 'j^P^^-V?
                                          -^•~>' - -: - "i^aaSaSHSssaagfcfei*


         -.- -f+33h.3L —i
                                   -.-               .
•-./ - -.:-^a%i ;
                               probably the worst offender, in that it
                               bleaches or alters the colors of many of
                               the sensitive organic  reagents  which
                               serve as titration indicators and as color
                               developers  for  photometric  methods.
                               Among the methods which have proved
                               effective in removing chlorine residuals
                               are: the addition of minimal amounts
                               of  sulfite,  thiosulfate  or arsenite;  ex-
                               posure to sunlight or an artificial ultra-
                               violet source; and prolonged storage.
                                Whenever interference is encountered
                               or  suspected, and  no specific recom-
                               mendations  are  found in this  manual
                               for overcoming it, the analyst must en-
                              deavor to determine what tecbnic,  if
                              any, suffices  to  eliminate  the inter-
                              ference without adversely affecting the
                              analysis itself. If two or more choices
                              of procedure are offered, often one pro-
                              cedure  will be less affected than an-
                              other by the presence of the intcrferin°
                              substance. If different procedures yield
                              considerably different results, it is likely
                              that interference  is present.  Some in-
                              terferences become less severe upon di-
                              lution, or upon use of smaller aliquots;
                              any  tendency  of the results to increase
                              or decrease in a consistent manner with
                             dilution  indicates  the likelihood of
                             interference effects.
                               a. Interference may cause the ana-
                             lytical results  to be either too high or
                             too low, as a consequence of one of the
                             following processes:
                               1) An interfering substance may re-
                             act like the substance sought, and thus
                             produce  a high result—for  example,
                             bromide will  respond  to  titration as
                             though it were chloride.
                               2) An interfering substance may re-
                            act with the substance sought and thus
                            produce  a  low result—for example,
                            chloride will react with a portion of the
                            nitrate in  the presence of  the sulfuric
                                                                               GENERAL INTRODUCTION  (000)
   acid,  using  the  phcnoldisulfonic acid
     3)  An  interfering  substance  may
   combine with the analytical reagent and
   thus prevent it from reacting with the
   substance sought—for example, chlo-
   rine will destroy many indicators and
   color-developing reagents.
     Nearly every interference will fit one
   of these classes.  For example, in a
   photometric method, turbidity may be
   considered as a "substance" which acts
   like the one being determined—that is
   it reduces the transmission of light. Oc-'
  casionally, two or more interfering sub-
  stances, if present simultaneously, may
  interact in a nonadditive fashion, either
  canceling or enhancing  one another's
    b.  The best way to minimize inter-
  ference  is to remove  the interfering
  substance or to render it innocuous by
  one of these methods:
    1)  Either the substance sought or
  the interfering substance  may be  re-
  moved physically: For example, fluo-
  ride and ammonia may be distilled off
 leaving  interferences  behind; chloride
 may be converted to silver chloride and
 filtered off, leaving nitrate behind  The
 interferences may also be adsorbed on
 an ion-exchange resin, a  process de-
 scribed more fully in Section  100B.
   2) The pH may be adjusted so that
 only the substance sought will react
   3) The sample may be oxidized or
 reduced  to convert the interfering sub-
 stance to a harmless form—for exam-
 ple,  chlorine  may be reduced to chlo-
 ride by adding thiosulfate.
   4) The addition of a suitable agent
 may complex the interfering substance
so that it is  innocuous although still
present:  For example, iron  may be
complexed wilh pyrophosphate to prc-


vent it from interfering with the copper
determination;  copper may be  com-
plexcd with cyanide or sulfide to pre-
vent interference with the  titrimetric
hardness determination.
  5) A combination of  the first four
technics may  be used: For example,
phenols are distilled from an acid solu-
tion to prevent amines from distilling;
thiosulfate  is  used in the dithizone
method for zinc to prevent most of the
interfering metals from passing into the
carbon tetrachloride layer.
   6) Color and turbidity may  some-
times be destroyed by wet or dry ash-
ing, or may be removed by use of a
flocculating agent.  Some types of tur-
bidity may be  removed by filtration.
These procedures,  however, introduce
the  danger that the desired  constituent
will also be removed.
   c. If none of these technics is prac-
tical, several methods of compensation
can be used:
   1)  If the color or tuibidity initially
present  in  the  sample interferes in  a
photometric determination, it may be
possible to use photometric compensa-
tion.  The technic  is described in Sec-
tion OOOA.7 preceding.
   2)  The  concentration of interfering
substances may be determined and then
identical amounts may be added to the
calibration standards.   This  involves
 much labor.
   3)  If the interference does not con-
 tinue to increase as the concentration
 of interfering substance increases, but
 tends to level off, then a large excess of
 interfering substance may be added
 routinely to all samples and to all stand-
 ards.  This is called "swamping."   For
 example, an excess of calcium is added
 in  the photometric  magnesium deter-
  4)  The presence in the chemical re-
agents of the substance sought may be
accounted for by carrying out a blank

10. Recovery
  A qualitative estimate of the presence
or absence of interfering  substances in
a particular determination may be made
by means of a recovery procedure.  Al-
though this method does not enable the
analyst  to apply any correction factor
to the results of an analysis, it does give
him some basis for judging the applica-
bility of a particular method of analysis
to a  particular sample.  Furthermore,
it enables the analyst to obtain informa-
tion in this regard without an extensive
investigation   to  determine exactly
which substances can interfere in the
method used.  It also does away with
the necessity of making separate deter-
minations on the sample for the inter-
fering substances themselves.
   A recovery may be performed at the
same time as the determination itself.
Of course, recoveries would not be run
on a routine basis with samples \\hose
general composition is known or when
using a method whose applicability  to
 the sample  is  well established.  Re-
 covery methods are to be regarded  as
 tools to remove doubt  about the ap-
 plicability of a method  to  a sample.
 In brief,  the  recovery  procedure in-
 volves  applying the anal>lical method
 to a reagent blank; to a series of known
 standards covering  the expected range
 of concentration of the  sample; to the
 sample itself, in at least a duplicate run;
 and to the recovery samples, prepared
 by adding known quantities of the sub-
 stance sought to separate portions of
 the sample itself, each portion equal to
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                             the size of sample taken for the  run.
                             The substance sought should be added
                             in sufficient quantity to overcome the
                             limits of error of the analytical method,
                             but  without  causing the total  in the
                             sample to exceed  the  range of the
                             known standards used.
                                The  results  are  first corrected by
                             subtracting  the  reagent blank   from
                             each of the  other determined values.
                             The resulting known standards are then
                             graphically  represented.  From   this
                             graph, the amount of sought substance
                             in the sample alone is determined.  This
                             value is then subtracted from each of
                             the  determinations  consisting of  sam-
                             ple plus known added substance.  The
                             resulting  amount of substance divided
                             by the known amount originally added
                             and multiplied by  100  gives the per-
                             centage recovery.
                                The procedure outlined  above may
                             be applied to colorimetric  or instru-
                             mental methods of analysis.  It may
                             also be applied in a more simple form
                             to titrimetric,  gravimetric  and  other
                              types of analyses.
                                Rigid rules concerning the percentage
                             recoveries required for acceptance of

results of analyses for a given sample
and method cannot be stipulated.  Re-
coveries of substances in the range of
the sensitivity of the method may, of
course, be very high or very low and
approach a value nearer to 100% re-
covery as the error of the  method be-
comes small with  respect to the mag-
nitude of the  amount of  substance
added. In general, intricate and exact-
ing  procedures for  trace  substances
which have inherent errors due to their
complexity  may give  recoveries that
would be considered very  poor and
yet,  from the practical viewpoint of
usefulness of the result, may be quite
acceptable.  Poor  results  may reflect
either interferences present in the sam-
ple or real inadequacy of the method of
analysis  in the range  in  which it is
being used.
   It must be stressed, however, that the
judicious use of recovery  methods for
the evaluation of analytical procedures
and  their  applicability to  particular
samples  is an invaluable  aid  to the
analyst in  both routine and research
                                                   000 B.   Expression of  Results
               1. Units

                Analytical results should be expressed
               in milligrams  per liter  (mg/1).   As-
               suming that 1 liter of water, sewage or
               industrial  waste  weighs 1  kilogram,
               milligrams  per liter is equivalent to
               parts  per  million.*  Only  the signifi-
               cant figures (see Section OOOB.2 be-
               low) should be recorded.
                 If the concentrations are  generally
               less than 1 mg/1, it may be more con-
 venient to express the results in micro-
 grams per liter (pg/1).  This is equiv-
 alent to parts per billion (ppb), where
 billion is understood to be 109.  If the
 concentration  is  greater than  10,000
   * It should be noted that, in water analy-
 sis,  "parts per million" is always understood
 to imply a weight/weight ratio, even though
 in practice a \olume may be measured in-
 stead  of a weight.  By contrast, "percent"
 may be either a volume /volume or a weight/
 weight ratio.


mg/1, the results should be expressed in
percent,  1 % being equivalent to 10,000
  In reporting analyses of stream pol-
lution or evaluating plant operation and
efficiencies, it is desirable to express the
results on  a weighted basis,  including
both the concentration and the volume
of flow in cubic  feet per second  (cfs)
or million gallons daily (mgd).  These
weighted results  may be  expressed as
quantity units  (QU)  according to  the
practice  of the U.S. Public Health Ser-
vice; as  pounds per 24 hr; or as popu-
lation  equivalents  based  on  biochem-
ical oxygen  demand  (BOD).   Totals
of the weighted units may be  converted
to  the weighted average mg/1.   The
various units are calculated as follows:
                  X( 1,000 cfs)
                  X (mgd)
  lb/24 hr = (mg/1) X (mgd) x 8.34
  lb/24 hr = (mg/1) X (cfs) X 5.39
  Population equivalent
    = (mg/1 5-day BOD) X (mgd) X

  Table 000(1)  presents  the factors
which are useful for converting the con-
centrations  of the common ions  found
in water—from milligrams per liter to
milliequivalents  per  liter,  and  vice
versa.  The term milliequivalent used
in  this table represents 0.001  of an
equivalent  weight.   The  equivalent
weight, in turn, is defined as the  weight
of  the ion (sum of the atomic weights
                      TABLE 000(1): CONVERSION FACTORS*

                   (Milligrams per Liter—Milliequivalents per Liter)
Ion (Cation)
me/1 =
0 08226
mg/l =
Ion (Anion)
me/l =
mg/1 X
mg'l =
40 03
48 03
    • Factors are based on ion charge and not on redox reactions which may be possible for
 certain of these ions. Cations and anions are listed separately in alphabetical order.

                                  of the atoms  making up  the ion)  di-
                                  vided bv  the  number of  charges nor-
                                  mally  associated  with  the parttcular
                                  ion   The factors for converting results
                                  from mg/1 to me/l were  computed by
                                  dividing the ion charge by the weight of
                                  the  ion.   Conversely,  the  factors  for
                                  converting results from me/1 to mg/1
                                  were calculated by dividing the weight
                                  of the ion by the ion charge. This table
                                  is offered for the convenience of labora-
                                  tories which  report results in  me/1 as
                                  well as mg/1.

                                   2. Significant Figures
                                     To avoid ambiguity in reporting re-
                                   sults or in presenting directions for a
                                   procedure, it is the custom to use "sig-
                                   nificant figures."   All  the  digits in a
                                   reported result  are expected   to be
                                   known  definitely,  except for the  last
                                   digit, which may be in doubt.  Such a
                                   number is said to  contain only signifi-
                                    cant figures.  If  more  than a single
                                    doubtful disit is carried, the extra digit
                                    or digits are not significant.   K an
                                    analytical result is reported as  75.&
                                    mg/1" the analyst should be quite cer-
                                    tain of the "75," but may be uncertain
                                    as to whether the  ".6" should be .5 or
                                     7 or even .4 or .8, because of unavoid-
                                    able uncertainty in the analytical pro-
                                    cedure. If the standard deviation  were
                                    known from previous  work to be ±2
                                     mg/1,  the analyst would  have, or at
                                     least should have, rounded  off the re-
                                     sult to "76 mg/1" before reporting it.
                                     On the other hand, if the  method were
                                     so good that a result of "75.61 mg/1
                                     could have  been  conscientiously  re-
                                     ported,  then the analyst should not
                                     have rounded it off to 75.6.
                                        A  report should present only such
                                     figures as are justified by the accuracy
                                     of the work. The all too common prac-

tice of requiring  that quantities listed
in a column have the same number of
figures to the right of the decimal point
is justified  in bookkeeping, but  not in
chemistry.                  .        .
   a. Rounding off:  Rounding off  is
accomplished by dropping the digits
which are  not significant.  If  the digit
6, 7, 8 or 9 is dropped, then the pre-
ceding digit must be increased by one
 unit; if  the  digit 0, 1. 2, 3 or  4 is
 dropped,  the  preceding digit  is  not
 altered.  If the digit 5 is dropped, the
 preceding  digit is  rounded off to the
 nearest  even number:  thus  2.25 be-
 comes 2.2, and 2.35 becomes 2.4.
    b.  Ambiguous zeros:   The  digit 0
 may record a measured value of zero,
  or it may serve  merely  as a  spacer
  to locate  the decimal point.  If the re-
  sult  of a sulfate  determination is re-
  ported as 420 mg/1, the recipient of the
  report may be  in doubt whether the
  zero is significant or not, because the
  zero cannot be  deleted.  If  an analyst
  calculates a total  residue (total solids)
  content of 1,146 mg/1, but realizes that
   the 4 is somewhat doubtful and that
   therefore the 6 has no significance, he
   \vill round off the answer to 1,150 mg/1
   and so report, but here, too, the recip-
   ient of the report  will not know whether
   the  zero is significant.  Although the
   number  could be expressed as a power
   of  10 (e.g., ll.SxlO3 or 1.15x10').
   this form  is not generally  used, as it
   would not be  consistent with the nor-
   mal expression of results and might also
   be  confusing.    In most  other  cases.
   there will be no doubt as to the sense in
   which the digit 0 is used.  It is obvious
   that the zeros are significant in sucti
    numbers as 104,40.08, and 0.0003. In
    a number written as 5.000, it is under-
    stood that all the zeros are significant.
    or else the number  could have been


rounded off  to 5.00, 5.0, or 5, which-
ever was  appropriate.   Whenever the
zero is  ambiguous, it  is advisable to
accompany the result with an  estimate
of its uncertainty.
  Sometimes,  significant  zeros  are
dropped without good cause. If a buret
is read as "23.60 ml," it should be so
recorded,  and not as "23.6 ml."  The
first number indicates  that the analyst
took the trouble to estimate the second
decimal place; "23.6 ml" would indi-
cate that he read the buret rather care-
   c. The plus-or-minus (±) notation:
If  a calculation  yields  as  a result
"1,476 mg/1" with a standard deviation
estimated as  ±40 mg/1, it  should be
reported  as  1,480 ±40 mg/1.   But if
the standard  deviation is estimated as
 •*00  mg/1,  the answer should  be
    nded off still further and  reported
    1,500+ 100  mg/1.   By this device,
ambiguity is avoided and the  recipient
of the report  can tell that the  zeros are
only spacers.  Even if the problem of
 ambiguous  zeros is not present, show-
 ing the standard deviation is helpful
 in that it provides an estimate of re-
    d. Calculations:  As a practical op-
 erating rule, the result of a calculation
 in which several numbers are multiplied
 or divided  together should be rounded
 off to as few significant figures as are
 present in  the  factor with the fewest
 significant  figures.  Suppose  that the
 following calculation  must be made  in
 order to obtain the result of an analysis:
          56 X 0.003462 X 43.22
A ten-place desk calculator yields an
answer  of  "4.975740996,"  but  this
number must be rounded off to a mere
"5.0"  because one  of the  measure-
ments, 56, which entered into the cal-
culation has only two significant figures.
It was a waste of time to measure the
other three factors to four significant
figures because the "56" is "the weak-
est link in the chain"  and limits the
accuracy of the answer.  If the other
factors  were measured to  only  three,
instead of four, significant figures, the
answer would not suffer and the labor
would be less.
   When  adding or subtracting num-
bers, that number which has the fewest
decimal places, not necessarily the few-
est significant figures, puts the limit on
the  number of places  that may justifi-
 ably be carried in the sum or difference.
Thus the sum


 must be rounded off to a mere "4,928,"
 no decimals, because one of the ad-
 dends, 4,886, has no decimal places.
 Notice that another  addend, 25.9, has
 only three significant figures and yet it
 does not  set a limit to the number of
 significant figures in the answer.
    The  preceding  discussion  is neces-
 sarily oversimplified, and  the reader is
 referred to the bibliography for a more
 detailed discussion.
                                                          l&' ••
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                                                 GENERAL INTRODUCTION (000)

                    000  C.   Precision and Accuracy
        ' • - -Tjtf  1«
   A clear distinction should be made
between the terms "precision" and "ac-
curacy"  when applied  to  methods of
analysis.   Precision refers  to  the  re-
producibility  of  a method  when  re-
peated on a homogeneous sample under
controlled  conditions,   regardless  of
whether or not the observed values  are
widely displaced from  the true value
as a result of systematic  or constant
errors present throughout the measure-
ments.   Precision can be expressed by
the standard deviation.  Accuracy  re-
fers  to  the   agreement between   the
amount  of a  component measured by
the test  method and the amount actu-
ally present.   Relative error expresses
the difference between  the  measured
and the  actual amounts, as a percent-
age of the actual  amount.   A  method
may have  very high precision  but  re-
cover only a part of the element being
determined; or an analysis, although
precise,  may  be in error  because of
poorly  standardized  solutions, inac-
curate   dilution  technics,   inaccurate
balance  weights,  or improperly  cali-
brated equipment.  On the other hand,
a method ma\ be accurate but lack pre-
cision because of low instrument sensi-
tivity, variable rate of biologic activity,
or other factors beyond  the control of
the analyst.
   It is possible to determine both the
precision and the accuracy  of a  test
method by analyzing samples to which
known   quantities  of   standard  sub-
stances have been added. It is possible
to determine  the precision,  but  not the
accuracy, of such methods  as those for
suspended  solids, BOD, and numerous
physical  characteristics because of the
unavailability  of  standard  substances
that can be added in known quantities

                                                                         !     I

about the mean is related to the stan-
dard deviation.  For example, 68.27%
of the observations lie between x ± I a\
95.45%, between x ± 2 v\ and 99.70%,
between x ± 3 a. These limits do  not
apply exactly for any finite sample from
a  normal  population;  the  agreement
with them may be expected to be better
as the number  of observations, n, in-
   b. Application  of standard  devia-
tion:  If the standard deviation, «r, for
a  particular analytical procedure  has
been determined from a large number
of samples, and a set of n replicates on
a sample gives a mean result x, there is
a  95%  chance that the true value of
the mean for this  sample  lies within
the values x±l.96a/\fn.  This range
is known as the 95% confidence inter-
val.  It provides an estimate of the reli-
ability of the mean, and may be used to
forecast  the   number  of   replicates
 needed to secure suitable precision.
   If the standard deviation is not known
 and is  estimated from  a single  small *
 sample, or a few  small samples, the
 95%  confidence  interval of the mean
 of n observations is given by the equa-
 tion  x ± to/^fn, where / has the fol-
 lowing values:
  c. Range (R):  The  difference be-
tween the smallest and largest of n ob-
servations is also closely related to the
standard deviation. When the distribu-
tion of errors is normal in form, the
range, R, of n observations exceeds the
standard deviation times a  factor dn
only in 5% of the cases.  Values for
the factor dn are:
 The use of / compensates for the ten-
 dency of small samples  to  underesti-
 mate the variability.
   • A  "small sample" in statistical  discus-
 sions  means a small number of replicate
 determinations, n, and docs not refer to the
 quantity used for a determination.
   As  it is rather  general practice to
 run replicate  analyses, use  of these
 limits  is very convenient for detecting
 faulty technic,  large sampling errors,
 or other assignable causes of variation.
   d. Rejection of experimental data:
 Quite often in a series  of observations,
 one or more  of  the  results  deviate
 greatly from the  mean,  whereas the
 other  values are  in close  agreement
 with the  mean value.  The  problem
 arises at this point as to rejection of the
 disagreeing values. Theoretically, no re-
 sults should be rejected, since the pres-
 ence of disagreeing results shows faulty
 technics  and therefore casts doubt on
 all the results.   Of course the result of
 any test in which a known error has
 occurred  is rejected immediately.  For
 methods for  the rejection of other ex-
 perimental data, standard texts on ana-
 lytical chemistry  or  statistical  mea-
 surement should be consulted.
    e.  Presentation of precision and ac-
 curacy data:  The precision and accu-
 racy data are presented in one of three
 ways  in  this  volume, depending  on
 when and how the  information was
 originally assembled.


• '•£&&*&£
. *4 . j»fc^(t*. '.t «
  In point of time, the oldest data are
given in  the  \vastcwatcr section  and
present  for the most part the precision
with which certain determinations can
be  performed.  These  data first ap-
peared in the  10th Edition and  survive
unchanged in the current volume.  The
complex character of wastewater  sam-
ples initially dictated this approach.
  Beginning  with  the llth  Edition, a
concerted effort was made to offer an
idea of the   precision  and accuracy
with which selected methods  can  bs
applied  on a  broad geographic basis in
examination  of the relatively  simpler
water samples.  The manner  of best
expressing the resulting data has re-
mained  to this day a matter of relent-
less study.  The llth and  12th Edi-
tions  presented  both  precision  and
accuracy in terms of mg/1.  This prac-
tice is retained for the time being where
such data continue to be cited in this
manual.  However, experience of the
past decade suggests that data  can be
presented  with greater  brevity  and
easier understanding in the  form of a
percentage.   By this system, the  stan-
dard deviation is  expressed  as a per-
centage of the mean and is now termed
the  relative   standard  deviation.  It
measures the precision or reproducibil-
ity  of  a  method,  independent of the
known  concentration  of the  sample
constituent. Similarly, the relative error
gives the difference between the mean
of a series of test results and the true
value, expressed as a percentage of the
true value.   Thus,  the  relative  error
represents the measure of the accuracy
of a method.   The relative standard de-
viation  and relative error are preferred
in quoting the precision and accuracy
of a method  because they are indepen-
dent of  the concentration.
  /. Quality control:  Quality  control

may be defined for the purpose of this
manual as a statistical system for moni-
toring the precision (variation), or rc-
producibility, of analytical  procedures
in a given laboratory.
  The control chart provides an impor-
tant tool for identifying the causes  of
variation in the quality of a procedure.
Certain  variations  in chemical proce-
dures  occur  by chance,  about which
little or nothing can be done.  How-
ever,  variations can also  result from
"assignable causes" such as differences
in methods, reagents, equipment, and
the skill of  persons performing  the
tests.  Chance  variations behave  in a
random manner and show no cycles,
runs, or similarly recognizable pattern.
If, on the other hand, the variations in
the data exhibit cycles, runs, or a  defi-
nite pattern, at least  one  assignable
cause may  be at work, and the  con-
ditions  producing  the variations  are
said to be "out of control."
  Two  basic types  of control charts
have proved  valuable.  The jc-chart is
used to monitor the average of a pro-
cedure,  while the  7?-chart is  used  to
monitor the variability of a procedure.
An x-chart discloses the  variation in
the averages of a  number of replica-
tions of a given procedure.   It consists
of a  central line,  x, and  upper and
lower control limits, which may range
from +lo- to  +3o- and -lo- to -So- stan-
dard deviations from the center  line.
(The  values  of x and the standard de-
viation  are derived  from past data.)
Figure 5 in Section 100C.1 illustrates
one application of control charts.   As
long as the sample averages remain in-
side the  control limits and  show only
random variation within the limits,  the
procedure  is said  to be "in  control"
with respect to its central tendency.   If
an  average  falls outside the  control

 book on Statistical Techniques for Col-
 laborative  Tests offers valuable infor-
 mation on  collaborative tests.
2. Graphical Representation of Data

 limits, or if there is nonrandom varia-
 tion within the limits, the process is said
 to be "out of control" with respect to
 its central tendency.  Such a condition
 should prompt an investigation into the
 assignable cause or causes of the ex-
 treme variation.
   The same basic principles which ap-
 ply  to  the I-chart  also  hold  for the
 /Z-chart,  except that the J?-chart is a
 plotting  of the ranges of samples.  It
 reveals variations in the ranges of sam-
 ples rather than variation in the aver-
 ages of samples.
   One of the most important factors in
 a quality control program is an ade-
 quate supply of a stable known control.
 This control can be a large sample from
 a natural source  known to  contain the
 constituent of  concern or  a synthetic
 sample prepared in the laboratory from
 chemicals of the highest  purity grade.
 Once the test to be controlled has been
 selected,  20 or  more  determinations
 for the same constituent in the control
 sample  are made under  routine daily
 conditions. The values are then  totaled
 and the average value is obtained. The
 standard deviation is calculated  to as-
 certain the range of allowable variation
 that can be expected in routine work
 for this particular constituent.   If this
 same sample is then treated as  a rou-
 tine daily control sample, it is possible
 to determine by  the use of a control
 chart constructed from  the  original 20
 determinations whether the daily assays
 for this  constituent  are in or  out  of
control.   When the  control sample is
 prepared from chemicals of the highest
purity, the probable accuracy  of the
determination can also be estimated.
  Duncan's volume on Quality Control
and  Industrial  Statistics describes the
I- and /?-charts in detail and their rel-
evance to quality control.   Youden's
   Graphical representation of data is
one of the simplest methods for show-
ing the influence of one variable on an-
other. Graphs are frequently desirable
and advantageous in colorimetric analy-
sis because they show any variation of
one variable with  respect to the  other
within specified limits.
   a.  General:  Ordinary  rectangular-
coordinate  paper  is  satisfactory  for
most  purposes.  Twenty lines per inch
is recommended.  Semilogarithmic pa-
per is convenient when one of the co-
ordinates is to be  the logarithm of an
observed variable.
   The five rules  listed  by Worthing
and Geffner for choosing the coordi-
nate scales are useful. Although  these
rules  are not inflexible, they are  satis-
factory.  When doubt arises, common
sense should prevail.  The rules  are:
   1)  The independent and dependent
variables should be plotted on abscissa
and ordinate in a manner which can be
easily comprehended.
   2)  The scales should be chosen so
that the value of cither coordinate can
be found quickly and easily.
   3)  The curve should cover  as much
of the graph paper  as possible.
   4)  The scales should be chosen so
that the slope of the curve approaches
unity  as nearly as possible.
   5)  Other  things  being equal,  the
variables should be chosen to give a
plot which will be as nearly a  straight
line as possible.
  The title of a graph should adequately
describe  what the  plot is  intended to
show.  Legends should be presented on
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 ' I

                           the graph to clarify possible  ambigui-
                           ties.  Complete information on the con-
                           ditions under which the data  were ob-
                           tained should be included in the legend.
                             b.  Method of least squares:  If suf-
                           ficient points are  available  and  the
                           functional relationship between the two
                           variables  is  well  defined, a smooth
                           curve can be drawn through the points.
                           If the function is not well defined, as is
                           frequently the case when using experi-
                           mental  data,  the  method   of least
                           squares is used to fit a straight  line to
                           the pattern.
                             Any straight line can be represented
                           by the equation x = my + b. The slope
                           of the line is represented by  the con-
                           stant m and the slope intercept (on the
                           x axis)  is represented by the constant
                           b.  The method  of least  squares has
                           the advantage of giving a set of values
                           for these constants not dependent upon
                           the judgment of the investigator.  Two
                           equations besides the one for a straight
                           line are involved in these calculations:
                                     m =
                                         nZ>-« - (Syr
                n being the  number of  observations
                (sets of x and y values) to be summed.
                In order to compute the constants by
                this method, it is first necessary to cal-
                culate 2*, Sy,  Sy2,  and 5*y.   These
                operations  are  carried  out  to more
                places than the number  of significant
                figures  in  the experimental  data be-
                cause the  experimental values are as-
                sumed to be exact for the purposes of
                the calculations.
                  Example: Given the following data
                to be graphed, find the best line to fit
                the points:
                                                                            GENERAL INTRODUCTION (000)
                                                       Let y equal  the absorbance  values
                                                       which are subject to error, and x  the
                                                       accurately  known  concentration  of
                                                       solute. The first step is to find the sum-
                                                       mations (2) of x, y, y2, and xy:
                                                       2 = 273.8
                                                         The next step is to substitute  the
                                                       summations in the equations for m and
                                                       b; ii = 7 as there are seven sets of x
                                                       and y values:
                                                                        7 (117.81)-2.80(273.8)
                                                                           7 (1.40) — (2.80)'
                                                                                    = 29.6
      1.4 (273.8)-2.80 (117.81)
          7 (1.40)-(2.80)*    -27.27

  To plot the line, three  convenient
values of y are selected—say, 0, 0.20,
0.60—and corresponding values of x
are calculated:

  jr. = 29.6(0) -f 27.27 = 27.27
  JT, = 29.6(0.20) + 27.27 = 33.19
  x, = 29.6(0.60) + 27 27 = 45.04

  When the points representing these
values are plotted on the graph, they
will lie in  a straight line  (unless an er-
ror in calculation  has  been  made),
which is  the line of best  fit  for  the





| 04
I 0.3
	 — r 	
e Enpenmental Data




   30         40
Solute Concentration - rog/l
 Figure 2.  Example of least-bquares method.

 given data.  The  points representing
 the latter are also plotted on the graph,
 as in Figure 2.

 3. Self-Evaluation (Desirable Philosophy
    tor the Analyst)
    A  good analyst  continually tempers
 his confidence with doubt.  Such doubt
 stimulates  a search for new and  dif-
 ferent methods  of  confirmation for his
 reassurance.  Frequent self-appraisals
 should embrace every step—from  col-
 lecting samples to  reporting results.
    The  analyst's first critical scrutiny
 should be directed at the entire sample
 collection process in order to guarantee
 a representative sample for the purpose
 of the analysis and to avoid any  pos-
 sible losses or contamination during the
 act of collection.  Attention should also
 be given to the type of container and to
  the manner of transport and storage, as
  discussed elsewhere in this volume.
     A periodic  reassessment should  be
  made of the available analytical meth-
ods, with an  eye to applicability for
the purpose and the situation.  In ad-
dition, each method  selected must be
evaluated by  the analyst  himself for
sensitivity,  precision and  accuracy,
because only in this way can he deter-
mine whether his technic is satisfactory
and whether he has interpreted the di-
rections  properly.   Self-evaluation on
these points can give the analjst confi-
dence in  the value and significance of
his reported results.
   The benefits of less rigid intralabora-
tory as  well as  interlaboratory eval-
uations deserve serious consideration.
The analyst can regularly check stan-
dard or unknown concentrations with
 and without  interfering elements,  and
 compare results  on the same sample
 with other workers  in the  laboratory.
 Such programs can uncover weaknesses
 in the analytical chain and  enable im-
 provements to be instituted without de-
 lay.  The results can disclose whether
 the  trouble stems from  faulty sample
 treatment, improper elimination of in-
 terference, poor calibration  practices,
 sloppy experimental technic, impure or
 incorrectly standardized  reagents,  de-
 fective instrumentation,  or even inad-
 vertent mistakes in  arithmetic.
    Other checks of a water  analysis are
 described in Section 100C  and involve
 anion-cation balance, specific conduc-
  tance, ion exchange, and the recovery
  of added substance in the sample (see
  also Section OOOA.10 preceding).
     All these  approaches are designed to
  appraise and upgrade the level of lab-
  oratory performance and  thus inspire
  greater  faith in the final reported re-

                                                                                          !-- "/^~~->--£y%~' 4?t ;>:%
                                                                                          I "'V^SBf '\- '?.. ^CJ" '.'^
                                    < *T_ .•a**- £ *> .•sri- •:
                                                              «&*!»» -™t:
                                                              ^ -_»-;_^ Vi» /" fl*

              200  D.   Methods Evaluation  by the Co.T.miiree
      The Committee on Standard Meth-
    ods of  the Water Pollution Control
    Federation has attempted to establish
    the precision and  accuracy  of  the
    methods in Part 200.  For many meth-
    ods, results were obtained  from  tea
    replicate determinations on 10 different
    days  or,  when  necessary,  from five
    replicate samples on 20 days.
      Most methods studied were found to
    be statistically reliable, and the standard

   each test, the number of analysts and
   determinations  is given  in shorthand
   form; for example,  "« = 5;  56x10,"
   which means that 5 different analysts
   ran 56 separate sets of 10 determina-
   tions each, making a total of 560 de-
   terminations.  Usually the precision is
   expressed as the standard  deviation in
   original  units  of measurement—i.e.,
   milligrams or miilUiters.   In a few in-
   stances,  the  precision is expressed as
   the coefficient of variation C, (the ratio
   of the standard deviation  to the aver-
   age), expressed as a percentage:
 deviations  given  may  be  used  with
 some confidence  in sutistical predic-
 tion.   If a method has been found
 statistically unreliable, this is indicated
 in the statements on  precision under
 the method.  The standard deviations
 of unreliable methods cannot safely be
 used for statistical prediction, but may
 be of some value for indicating roughly
 the variation that may be expected.
   In expressing the e\aluation data on
                                                         POLLUTED WATERS (200)
                 ICO a
  The standard  deviation given with
each method is based on careful labora-
tory examination.  No  attempt has
been made to obtain the standard devia-
tion under research conditions, or with
the use of specially calibrated apparatus
or  glassware.   The values  given  are
to be regarded as provisional in nature
and subject to change on further study.
In  general,  the  standard  deviations
given may be regarded  as  being  too
high rather than too low.


. >_ ' •
1 *. ^
f 1
1 1
• i ' i" •
5 . J i -.

L • x


 8.3   Specific Analytical Methods for the Analysis  of  Relatively Concentrated

         Leachate Samples

    8.3.1   Introduction

    Specific analytical methods  for the analysis  of  relatively  concentrated

 leachate samples were investigated in the report "Compilation  of Methodology

 for Measuring Pollution Parameters of Landfill Leachate":  by  E.S.K.  Chian

 and F.B.  DeWalle, University  of Illinois,  EPA Program  Element  No.  1DB064.   It

 is  stated in the abstract,  P. IV of the subject  report:

    "Since different  analytical  methods can be used  to  determine  a specific

 parameter,  a preliminary laboratory evaluation was  made of those methods least

 subject  to interferences.   All  analyses were conducted with a  relatively con-

 centrated leachate sample obtained from a  lysimeter filled with  milled solid

 waste.  The results  indicate  that  strong interferences are sometimes  encountered

 when using colorimetric  tests due  principally to  the color and suspended

 solids present  in leachate.   In such  instances,  alternative methods were evalu-

 ated or recommendations  were made  to  reduce the  interfering effects.  Automated

 chemical  analysis using  colorimetric methods can  sometimes experience significant


    Further  research  is necessary to evaluate additional methods  using leachate

 samples of  different strengths  and  collected from landfills of different ages.

 The precision and  sensitivity of each method will also have to be determined.

 The interfering parameter should be quantified to allow predictions of its

magnitude with leachate  samples of different strengths."

   Also,  in  the above-cited report, Introduction, P.3,  it is stated:

   "It is the purpose of the present study to review the analytical methods to

determine contaminants as reported in the literature.   The methods compiled and


 evaluated in  this study were generally reported  in  the  literature; additional

 information was obtained by  contacting the principal investigators.  Interferences

 in the chemical analysis due to  the  complex nature  of the leachate as enumerated

 in the reported studies are  listed in  this report.

    The compilation showed  that different methods subject to different interferences

 are used to determine a certain  parameter.  For each parameter, only that method

 was evaluated in this laboratory which was found to have the smallest interference.

 The laboratory evaluation  tested the method for its susceptibility to certain

 interferences commonly found in  leachate.  In addition,  the accuracy of the

 method was tested.  All laboratory analyses were performed using a high strength

 leachate sample obtained from a  recently installed lysimeter filled with milled

 refuse.   Recommendations made in this report,  therefore, only apply to  leachate

 of similar strength.   No evaluation was made of precision and sensitivity of

 each  method  since this was  beyond the scope of the work.  Realizing the above

 restrictions,  recommendations were made in the present study for the selection

 of those  methods  least subject to interference.   Further recommendations  were

 made  concerning modifications of the  selected  methods."

    8.3.2    Measurement  of  Interference Effects

    Two general procedures were used by  Chian and  DeWalle to  deal with interference

 effects in their  evaluation of specific analytical methods.   These  procedures

were  the  Standard Addition  Method and the  Dilution Method.   These methods are

discussed in this report on pp.  12-15,  which are  reproduced  herewith.

    In general,  it would be  expected that interferences encountered  in concentrated

leachates would be relatively severe  and constitute  "worst case" effects when

compared with more dilute leachates.  Leachates obtained in  the  field (landfills)

for analysis may vary greatly in  total  concentration, i.e. from  total concentration

 j                            SECTION 5

•j      Since most of the leachate studies have been conducted by researchers in
' the sanitary or environmental engineering fields, the methods that are used
  closely  reflect those of Standard Methods (APHA, 1971).  Studies between
  I960 and 1965 used the llth edition, between 1965 and 1971 the 12th edition
  and after 1971 the 13th edition.  Laboratories not employing complicated
  instruments, sometimes use methods listed by Hach Chemical Company, Handbook
  of Water Analysis (Hach Chemical Company, 1973).  Methods used by geologists
  are generally those reported in Techniques of Water Resources Investigation
  of the U. S. Geological Survey (U. S. Geological Survey, 1970).  Recent
  studies  use the EPA procedures in Methods for Chemical Analysis of Water
  and Hastes (EPA, 1974) which also contain optional procedures for automated
  analysis.  Most studies employing automated chemical analysis, however, use
  methods  recommended by Techm'con Industrial Systems. Industrial Methods
  (Technicon, 1973).                            -

       The different parameters that have been determined in the studies
  reported in the literature are listed below.  Each section contains a survey
  of the different methods used to analyze a certain parameter, and the obtained
  experiences.   The method least interferred with by the matrix of the leachate
  sample was selected and then evaluated in greater detail in the present
  study.   The method was evaluated with the standard addition method and by using
  progressively increasing dilutions.


      The standard addition method is widely used in chemical analysis when
  interferences  present in the sample cannot be avoided.  An advantage of
  this method is that it avoids the necessity of preparing synthetic standards
  of  a composition similar to that of the sample (Geological Survey,
  1970).   In this method equal  volumes of sample are added to a water blank
  and standards  containing increasing but known anounts of the test element.
  The volume of  the blank and the standards must have the same volume to result
  in a similar dilution of the sample.  The diluted samples containing increasing
  amounts of the test element are then analyzed according to the standard
  procedures.   The obtained values are then plotted on the vertical axis of a
  graph while the concentration of the known standards are plotted on the
  horizontal  axis (Figure 3).  When the resulting line is extrapolated to
  zero measured  concentration,  the point of interception of the abscissa is
  the concentration of the unknown element.  The abscissa on the left of the
  ordinate is  scaled the same as on the right side, but in the opposite
= direction of the ordinate.   Since the scale of the ordinate and abscissa
  are identical, a line drawn under 45° from the extrapolated point on the
"abscissa to  the ordinate represents a 100 percent recovery of the added
  element.   Thus 100 percent of the known amount added to the diluted sample
  is recovered.   If the actual  line connecting the points has a slope lower
* than 45° the  recovery of the added element is less than 100 percent while a
  slope higher  than 45° represents a higher than ICO percent recovery.  The
]                                        8-27

Concentration, mg/J?
  Measured With
Standard Addition
                                      i:50 Dilution
                                      (72.5 % Recovery)
                                 I MOO Dilution
                                 (83 7o Recovery)

                                     	100 % Recovery

                                        I          I	
                    Added Concentration  Total-P, mg/J
       Figure  3.
           The Total-P Determination with  the  Ascorbic Acid
           Method in the  1:50 and 1:100  Diluted Leachate
           Sample Using the Standard Addition  Method


                                                                                   bUtttW4ftS9BUiVCH.CKBiXBIii^ 4lfc44&l
                              I   I          I    I
                            l?750 1:400 1:250     IM25  1:100
                               1:500  1:300  1:200

                                                            Dilution Factor
1:50   1:40   1:30   1:20
                      Figure 4.  The Total-P Determination with the Ascorbic Add Method 1n a Leachate
                                 Sample Using the Progressive Dilution Method

                                                                                                              i  i« •'

of minimum detectability to a highly concentrated product.   The ratios of

the individual contaminants present in the leachate are also variable and

must be considered when evaluating interference effects in  a given analytical


   The analyst, therefore, must always evaluate a specific  analytical method

relative to a specific leachate sample.  Several guidelines for handling inter-

ferences are of great value.  The judgment of the analyst is of prime importance

in applying the guidelines to Uhe specific problems at hand.  Experience with

a given leachate is obviously of practical value.  The degree of accuracy,

sensitivity and precision required in a specific analytical problem will con-

stitute foremost considerations in the final selection of the method and possible


8.4    Analytical Methods

In discussing individual analytical methods in their report, Chian and DeWalle

address the following aspects in each case:

Principle, Interferences, Previous Studies, Evaluation of The Method, Recommenda-

tions and Procedures.

The methods discussed in the report are as follows:

1.   Physical Parameters: pH, Oxidation Reduction Potential (ORP) and Specific

     Conductance, Residue.

2.   Organic Chemical Parameters:  C.O.U., T.O.C., Volatile Acids, Tannin and

     Lignin, Organic Nitrogen.

3.   Inorganic Chemical Parameters:  Chloride, Sulfate, Phosphate, Alkalinity

     and Acidity, Nitrate, Nitrite, Ammonia, Sodium and Potassium, Calcium

     and Magnesium.

4.   Biological Parameters:   B.O.D.,  Coliform  Bacteria  (Total and Focal).

5.   Miscellaneous Determinations

Tlic report also contains a useful  appendix of  parameters and methods used by

various investigators.   (Appendix  A,  P.  125 -  Survey of physical, chemical

and biological methods used by  various investigators).

3.5   Brief Description  of Specific Analytical Methods  for Leachate Analysis

Following is a brief description of the  analytical methods as recommended by

Chian and DeWalle for the analysis of concentrated leachate:

      1.   Physical Parameters:

           A.   pH Determination:

                Electronetric determination using a glass indicating

           electrode and a calomel reference  electrode or a combination

           electrode.  The procedure  is  according to Standard Methods,

           13th Edition, 1971,  p.279.

           B.   Oxidation Reduction Potential  (ORP):

                The measurement is made  with a pH meter, using a platinum

           indicating electrode and a calomel  reference electrode.  The

           pH determination is  made concurrently.

           C.   Specific Conductance  Determination:

                The determination  is  performed with a commercially available

           meter and an  electrode  with a cell  constant  of 1.0. Both tempera-

           ture and pH are determined concurrently, as  they affect the results.

           Reference is  made  to Standard Methods. 13th  Edition, 1971, pp.326-327.

           I).   Residue  Determination:

                Total solids  is determined after drying to constant weight

           at 103-105°C. and  the volatile solids is determined from the weight


     loss at 550°C. for one hour.  The suspended solids(filterable

     residue) is determined using a glass fiber filter and drying

     to constant weight at 103-105°C.  The following reference is

     given:   Standard Methods. 13th Edition, 1971, pp. 289,292,293

2.   Organic Chemical Parameters:

     A.   Chemical Oxygen Demand (C.O.D.):

          The C.O.D.  determination is performed according to Standard

     Methods. 13th Edition, 1971, pp. 496-499.   If the C.O.D.  is less

     than 100 mg/liter,  more accurate results may be obtained  by using

     the low level C.O.D.  procedure given on p.  498 of the same refer-


     B.    Total  Organic  Carbon (T.O.C.):

          The T.O.C.  analysis is run according  to Standard Methods.

     13th Edition,  1971,  pp.  257-259.

     C.    Volatile  Acids  (Total Organic Acids):

          Volatile  acids  are  determined by the  column-partition

     chromotographic  method as listed in  Standard Methods.  13th

     Edition,  1971, pp. 577-580.   Standard amounts of  acid  are  added

     to  determine the recovery of the method.

     D.   Tannin and Lignin

         The  tannin and lignin procedure  is  according  to Standard

     Methods.  13th Edition, pp.  346-347.

     E.   Organic Nitrogen:

         Organic nitrogen  is  determined according to Standard Methods.

     13th Edition, pp. 244-248.   A 300 ml.  sample,  50 ml. digestion

     reagent and 30 min. digestion period  are used.

3.   Inorganic Chemical Parameters:

     A.   Chloride:

          In biologically stabilized leachate samples in which

     color does not cause any interference, the chloride deter-

     mination is conducted with the mercuric nitrate method

     (Standard Methods.13th Edition, pp. 97-99).   In strongly

     polluted leachate, chloride is determined by the poten-

     tiometric titration method (Standard Methods. 13th Edition,

     pp.  377-380).

     B.   Sulfate:

          Sulfate is determined by the gravimetric method with

     drying of residue, according to Standard Methods.  13th Edition,

     1971,  pp. 332-333.

     C.   Phosphate:

          The aminonaphthol sulfonic acid or ascorbic acid method

     is used to measure total phosphorus concentration in leachate

     using  the persulfate digestion.  The amount  of recommended per-

     sulfate digestion reagent is 400 mg./lOO nl.  sample,  while the

     digestion tine recommended by Standard Methods is  sufficient to

     hydrolyze the  phosphorus.  The ortho-phosphate test  as determined

     by the ascorbic acid method does not experience significant

     interference and should be run on the anaerobically  stored

     leachate after as little dilution as possible.   In order  to obtain

     reliable results, a standard addition or progressive  dilution

     curve  should be established for the total phosphorus  determination.

     Such steps are not necessary  for the orthophosphate determination

     teferences for the total phosphate and ascorbic acid methods are

     Standard Methods. 13th Edition, 1971, pp.  524-526  and 532-534.

 The aminonaphthol sulfonic acid method reference is  Physical.

 Chemical and Microbiological Methods of Solid Waste  Testing;

 Four Additional Procedures;  N.  S.  Ulmer,  U.S.EPA,  NERC,

 Cincinnati,  1974.

 D.    Alkalinity and Acidity:

      The alkalinity and acidity determinations are made  poten-

 tiometrically on undiluted samples.   The  endpoints used  are  those

 determined  from the titration curve.   Standard 0.02N NaOH is

 used for the acidity determination and standard 0.02N H2S04

 or  HC1 is used for the  alkalinity  determination.   Reference  is

 Standard Methods.  13th  Edition,  1971,  pp.  52  and 55.

 E.    Nitrate:

      Nitrate is determined with  the  specific  ion electrode instead

 of  the brucine-sulfanilic  acid  colorimetric method.  It  is preferable

 to  measure the nitrate  with  the  electrode  in  the undiluted sample.

 Standard amounts of nitrate  should be  added to the sample to de-

 termine  the  recovery of the method.  When  the brucine-sulfanilic

 acid method  is  used,  the suspended solids  and color may be removed

with a massive  lime dosage of 5,000  to  10,000 mg./l. Ca(OH)2.

Aluminum hydroxide  is not  as effective  as  a coagulant.

F.   Nitrite:

     Nitrite  is determined by the  naphthylamine colorimetric pro-

cedure as outlined  in Standard Methods. 13th  Edition, 1971,pp.240-243.

The naphthylamine reagent  is replaced by   n-  (1-naphthyl) ethylene-

diamine  dihydrochloride.. Standard amounts of nitrite nitrogen are

added to  the  filtered sample.

G.   Ammonia

     Two methods are recommended for determination of ammonia.

One uses the selective  ion electrode with sufficient sample dilution


 to reduce matrix interference of the leachate.  (Reference:

 U.S. EPA Methods for Chemical Analysis of Water and Wastes.

 1974, pp. 165-167).  The other method uses distillation followed

 by titration of the ammonia in the distillate with standard 0.02N

 H2SO^, with mixed methyl red-methylene blue as the indicator.

 For this method, a maximum concentration of 75 mg/1. ammonia

 in the diluted sample is recommended, unless additional buffer  is

 used.   A pH of 7.4 is sufficiently high to distill off  the ammonia.

 A  pH 9.4 is too high, causing partial destruction of the organic

 nitrogen.   (Reference:   Standard Methods.  13th Edition,  1971,

 pp.  224-226 and 246-247).

 H.    Sodium and Potassium:

      Sodium and potassium  are determined by flame photometry

 (Reference:   Standard Methods.  13th Edition,  1971,  pp.  316-320,

 Sodium and  pp.  283-284,  Potassium).   Sodium and potassium may

 also be  determined  by atomic  absorption spectroscopy, in  which

 case it  is  recommended  that cesium be added  at  a  concentration of

 1,000  mg./l.  to suppress ionization of  the  analyte  ion  in the flame.

 (Reference:   Methods  for Chemical  Analysis  of Water  and Wastes.

 U.S.EPA,  1974:   Sodium,  pp. 147-148 and Potassium, pp. 143-144).

 I.   Calcium  and Magnesium:

     Calcium  and magnesium are determined by atomic  absorption

spectroscopy, using 10,000 mg./l.  lanthanum  to  reduce interference.

 (References:  Standard Methods.  13th  Edition 1971, pp. 212-213 and

Methods or Chemical Analysis  of Water and Wastes. U.S. EPA, 1974,

pp. 103-104,  Calcium  and pp.  114-115, Magnesium).

 J.    Hardness:

      Hardness is calculated from the concentrations of the

 individual polyvalent metals as determined by atomic absorption

 spectroscopy and should include Ca, Mg, Fe, Al, Zn, Cu and other

 polyvalent cations, expressed as CaC03 equivalents.

 K.    Heavy Metals:

      The heavy metals are determined with atomic absorption

 techniques.  Standard additions are used for leachates of high

 strength to determine the magnitude of the interference.  Stan-

 dard  additions should be used for the elements lead, copper,

 nickel and chromium but may be omitted for zinc and cadmium.

 For total metal analysis, the sample should be collected in a poly-

 ethylene bottle and acidified to pH2 with 1:1 redistilled nitric

 acid.  When the dissolved metals, those filterable through a

 0.45/*- filter, are determined, the suspended metals should be

 determined concurrently.                                      f

      The determination of arsenic and selenium by atomic absorption

 using the gaseous hydride method may not be satisfactory, since

 reduction to the trivalent form with SnCl2 may not be complete.

 The conversion to gaseous arsine after addition of zinc metal may

 also not be complete.  Colorimetric methods are therefore recommended.

 The analysis of mercury by atomic absorption with the cold vapor

 technique also depends on the reduction of the sample with SnSO^

 or SnCl2» which may not be complete when other oxidants in high

 concentrations are present.   (References:  Standard Methods, 13th

 Edition, 1971, p. 213; Methods for Chemical Analysis of Water and

Wastes. U.S.EPA, 1974, pp. 213 and 295-299, Selinium; Methods for


     Chemical Analysis  of Water  and Wastes, U.S.EPA, 1974, Calcium

     pp. 103-104, Magnesium  pp.  114-115,  Iron pp. 110-111, Aluminum

     pp. 92-93, Zinc pp. 155-156, Copper  pp. 108-109, Arsenic pp.9-10

     and 95-96, Selenium p.  145, Mercury  pp. 118-122).

4.   Biological Parameters:

     A.   Biochemical Oxygen Demand (B.O.D.):

          The B.O.D. determination is run according to Standard Methods,

     using dilution water which is seeded with settled domestic sewage.

     B.O.D. values obtained  should be judged carefully and be determined

     parallel with comparable chemical tests such as free volatile fatty

     acids, C.O.D. or T.O.C.  (Reference:  Standard Methods.  13th Edition,

     1971,  pp.489-495).

     B.   Colifonn Bacteria  (Total and Fecal):

          The most probable number (MPN)  technique should be  selected for

     leachate monitoring purposes, as opposed to the membrane filter  (MF)

     technique,  since it is able to detect bacteria at  lower  concentrations

     and is less subject to suspended solids interference.  Inactivation

     studies, however,  in which a certain amount of bacteria  is added to

     a  sample to study its subsequent  reduction  with time,  should be

     conducted if  the MF technique is  used.   Presumptive  and  confirmed

     tests  are run for total  coliforms and the completed  coliform test

     is run in those instances  where  leachate causes pollution  of drinking

     water  supplies.   (Reference:   Standard  Methods.  13th Edition, 1971,

     pp.  664-668).

         The fecal  coliform  MPN  procedure is used  as a confirmatory

     test procedure  in  conjunction with prior enrichment  in a presumptive

     test medium for optimum  recovery  of  fecal coliforms.   (Reference:

     Standard Methods,  13th Edition, 1971, pp.669-672)


       5.     Miscellaneous Determinations:

              Some of the miscellaneous leachate parameters which have

       been given attention in various studies are:   Methylene blue
       active substances, cyanide, fluoride, sulfide, si lien,  hcxanc

       solubles, ether solubles, color, visual appearance- and  odor.

8.5.1     Additional valuable information on specific analytical methods is
available in "Procedures for the Analysis of Landfill Leachate", Proceedings
of an Internation Seminar, Environmental Conservation Directorate, Ottawa,
Ontario, Report EPS-4EC-75-2, October 1975.

8.6    Field Testing Versus Testing in the Laboratory

The majority of tests performed on leachate samples are carried out in the

analytical laboratory on samples which have been preserved by  refrigeration

or chemical means.  A limited number of tests, however, can be performed at

the sampling site on a freshly drawn sample.  There are a number of advantages

in field testing, among which are that sample degradation is practically

eliminated, along with the need for sample preservation,  transportation and

handling.  An added advantage is the ability to re-sanple and  re-analyze

immediately, on site, if it is suspected that a particular sample is not

representative or valid.  There are also disadvantages encountered in field

testing and these usually relate to the reliability of the particular method

and equipment used for the test.

Some tests can be run in the field with the same methods and equipment

which would be used in the laboratory and yield the same reliability.  Among

such tests are those involving the measurement of pH, oxidation reduction

potential, specific conductance, turbidity, dissolved oxygen and specific

ions by means of specific ion electrodes.  The equipment used in these tests

is available in portable models which are of equal applicability in the field

and laboratory.

Other tests are sometimes performed in the field using methods and equipment


  specifically designed for field use.  A number of commercially available

  kits are available for such purposes.  These methods are not usually used

  in the analytical laboratory and are generally recognized as being applicable

  only to field testing.

  While offering distinct advantages, there are also disadvantages inherent

  in the use of field kits.  The following evaluation of field kit usage  is

  given in Handbook for Monitoring Industrial Wastewater.  U.S.  EPA,  Technology

  Transfer,  August 1973,  p.  5-141

"Estimating the Amounts of Pollutants Present by Use of "Kits""

        Companies,  such as  the Hach Chemical Company,  Delta Scientific, Inc.,

  and  Koslow Scientific Company have manufactured "Kits" for the analysis of

 various  constituents  of wastewater.   The kits consist  of  a small portable

 container  in which  all the necessary equipment  and  instructions are conveniently

 packaged and arranged to  perform a variety of tests.   No  previous laboratory

 training is required  and, within minutes, an indication of  the chemical con-

 stituents  in wastewater can  be determined.

       Koslow Scientific and  the  Hach  Company  provide kits  for determining

 the presence of heavy metals, such as Cd,  Hg  and Pb, and includes reagents

 for masking interferences.

       The major disadvantage in using kits is the inability of the pre-packaged

 devices and reagents  to effectively cope with interferences.  Reference  2

 (Standard Methods for the Examination of Water and Wastewater. 13th Edition,

 American Public Health Association, 1971)   outlines  procedures for the

 removal of interferences by pretreatment techniques and the reagents  necessary

 for masking these interferences that are usually not available in the kits.

 The accuracy of the tests performed with kits is usually less than  that  obtain-

 able with precise laboratory  techniques.   Kits give good results  in relatively

clean water but pose problems when used to anlayze wastewaters.  They

are nevertheless useful in preliminary surveys performed to determine

overall characteristics of a wastewater."

      This evaluation of the use of field kits for the analysis of indus-

trial wastewater is equally applicable in the case of leachate analysis.

Mobile Laboratories

      Although not in widespread usage, mobile analytical  laboratories have

the potential of providing a combination of laboratory capability and field-

testing convenience.  The instrumentation and general capability of a mobile

laboratory can vary over a wide range, depending upon its  application, manpower,

and the capital investment involved. By using normal laboratory equipment and

methods,  the mobile laboratory can obtain results equivalent  to those of a

conventional analytical laboratory, while incorporating all of the advantages

of field  kits.  Limitations imposed by sample degradability and work load will

be encountered by  the mobile laboratory in much the same way  as experienced

by the conventional laboratory under certain conditions.   If  a sample or

samples presented  to a mobile laboratory must be analyzed  for a large number

of parameters  (i.e. 20 or 30), then sample degradation versus work load will

have  to be addressed.  The sample will have to be preserved and the analyses

prioritized relative to order of degradability.  In  this respect,  the mobile

laboratory shares  the disadvantages of the conventional laboratory, along with

its advantages.

8.7   Automated Methods

      Automated wet chemistry methods  offer riany advantages,  among which  are

economy,  increased precision and accuracy when applied  to  repetitive analytical

work  loads of  significant volumes.  Federal,  state  and  local  regulatory agencies,

industry, educational institutions and independent  testing laboratories,  among

others,  use automated methods to handle large,  demanding  repetitive analytical

work  loads.

      Automated  wet  chemistry is addressed in the  "Handbook  for Monitoring

Industrial  Wastewater",  U.S.  EPA,  August 1973,  pps.  5-14, as follows:

            "Automated wet  chemistry is frequently  used in analysis of

      wastewaters and for automated monitoring of waste effluents.  When

      used,  the  system  consists of a sampler to select air,  reagents,

      diluents and filtered samples.   From the  sampler, the  fluids pass

      through a  proportioning pump and manifold where the fluids are

      aspirated, proportioned and  mixed.   The samples are then ready

      for separation by  passing  through any one of the following units:

      a dialyzer (continuously separates interfering materials in the

      reaction mixture)  a  digester (used for digestion, distillation or

      solvent evaporation), a continuous filter (for on-stream separation

      of particulate matter by a moving belt of filter paper) or a distilla-

      tion head  (separates high  vapor pressure  components).

           After separation,  the samples can be conditioned  in a constant

      temperature heating  bath.  After conditioning, the samples pass

      through a detection  system which may be a colorimeter, a flame

      photometer, a  fluorometer, a UV spectrophotometer, an  IR spectro-
               an atomic absorption spectrophotometer,
      photometer,/or a dual differential colorimeter.  The signals from

      the detection  system are sent  to a recorder  or a computer system."

      In the May 1975  issue of "Environmental Newsletter", a publication of

Technicon Industrial Systems,  a  list  of water quality major automated methods

is presented.  The list  is reproduced below.  It should be noted that ten (10)

of the methods are Federal Register approved and eleven (11) of the methods

are presented in the U.S.  EPA manual  "Methods for  Chemical Analysis of Water

and Wastes", 1974.


Acidity (Thymol Blue)
Alkalinity (Methyl Orange)
Ammonia (Dialysis)
..Chloride "• "•.''-;• ,~V- '. j'\ - rv"«'Ij!.''i^
. Chromium (Hexavalent) .- '-",.-r_/. :;./•;
- COD «•':•":•"• '-"•'•"-.. •"• 1.-"-", " •-
* Color ""' ••••£.. T .•• "• '"••' 5y-iVii"if-*"?-"s5
" Copper ''. '' '--•'." '"•' ".•"./.• -;;,'
Hardness (Total)
••'ate & Nitrite (Dialysis)' -.?.Xr-.--'^V
.gen (Ammonia) -•' .• ../"" "O'V^-"
• Nitrogen (Kjeldahl. Total) ":.•'•„• !;"";'
. Nitrogen (Nitrite) '• ' - *""';" --""';t't
Nitrogen (Nitrate & Nitrite) ' '..'- -:..-'"
Nitrogen (Organic plus Ammonia)

Phosphorus (Total)
Phosphorus (Total)
Pnosphorus {O-phosphate) _ ; -. •• . -.
Silicates - • ' • - '• . ' -
Sucrose - ' ' • . ...
Sutfate " ' ' ; ' :•-
Su'.fite .' ' ._ .'_'- _*"
)ther Method
_^_ - 	 	 	 	
.99-70W -.-:
162-71VV .-
137-7 1W •-'
181-72W ."

165-7 1W
271-73W. .
J46-70W '. .
102-7ffW .
100-70W /_

274-7 3W -
289-73W •
118-71W '
173-72VV .

* -_* ***•",••" "-• '
. "* ' T "*.*""* ^
t .... — , . .^

- x
•"••"." '.-"•'-•'.


fe^V '-""-'>
"-Vr -7;':?i"
"-;./":. " .~

::>"-: "•'-•'-•/-.
^ !,-»->• ••-"-

• 1 ." •
* -•' tf --",; ""

.-, c.t-.-.---,:,-
1974 EPA
Methods Book
Reference (D
P. 5

P.31; 7- . ;
~J-£-T '. ":-'.-.--"-V-V
- - :•• •
P. 61
P. 70
P. 127
P. 168 '*'.'. j
P. 190(SeO2) '

P. 220
P. 243
P. 256
'•'"".'.' :- -

X '
-. V.- - " ^
::\'^ ^

•• '-i" -:-"/:..

- . : x; >

Range '3)
0-0.2mg/l -;":"-']
0-100mg/l ":-:1
0-250 Units . '!
0-2mg/l - ,,
0-500 pg/l
0-1mg/l (ppm)
0-20 pg/l
0-1mg/l -""'t-i
0-10mg/l "---i.- •]
0-10mg/l • '~^'A
• ' •• ."•* - ' --" '"(
0-1mg7l (N) :'\
0-2mg/l (N) "J
or 0-10mg/l
0-500 pg/l
0-10mg/l •-•{
0-10mg/l / i
0-IOOmg/l '"}
0-300mg/l . j
. 0-3mg/l ." 1
1) S3t« EPA f/ethoc!s may differ in detail from the Technicon Listed Method. In such wses the method to be selected for use is
determined by review of sample matrices and ranges required
2) Method in practical use but gzn»ral regulatory approval not yet obtained
3) I.:e:hod ranees can be adjusted to suit particular rweds. Method resolution is typically 1% of f-jil scale.

A] fConvegien Institute for Water Research. Oslo. Norway, A. Henderson . I
•=« Manual d-s«tion folloivsd by autoanalysis for ammoniacal nitrogen. _ I

ii:s eo»»on»TiC"

      Automated methods are discussed in "Standard Methods for the Examination

of Water and Wastewater", 13th Ed., 1971, pps. 14-15, as follows:

            "Automated analytical instrumentation:  Automated analytica]

      instruments are now available and in use to run individual samples

      at rates of 10 to 60 samples per hour.  The same instruments can

      be modified to perform analyses for two to twelve constituents

      simultaneously from one sample.  The instruments are composed of

      a group of interchangeable modules joined together in series by  a

      tubing system.  Each module performs the individual operations

      of filtering, heating, digesting, time delay, color sensing, etc.

      that the procedure requires.

            The read-out system employs sensing elements with indicators,

      alarms and/or recorders.  For monitoring applications,   automatic

      standardization-compensation, electrical and chemical,  is  done by

      a self-adjusting recorder when known chemical standards are  sent

      periodically through the same analysis train.  Such instrument

      systems are presently available.

            Appropriate methodology is supplied by the manufacturer

      for many of the common constituents of water and wastewater.

      Some methods are based on procedures described in this  manual, while

      others originate from the manufacturer's adaptation of  published

      research.  Since a number of methods of varying reliability  may

      be available for a single constituent of water and wastewater, a

      critical appraisal of the method adopted is obviously mandatory.

            Automated methodology is susceptible to the same  interferences

      as the original method from which it derives.  For this reason,  new

      methods developed for automated analysis must be subjected to the

      exacting tests for accuracy and freedom from adverse response already

      met by the accepted standard methods.


            Off color  and  turbidity  produced  during  the course of

      an analysis will be  visible  to an  analyst manually performing a

      given determination  and  the  result will be  properly discarded.

      Such abnormal  effects  caused by unsuspected interferences might

      escape notice  in an  automated  analysis. Calibration of the

      instrument system at least once each day with  standards containing

      interferences  of known concentration could  help  to expose such

      difficulties.   Routine practice is to check instrument action

      and guard against questionable results by  the  insertion of

      standards and  blanks at  regular intervals  - perhaps after every

      10 samples in  the train.  Another  important precaution is proper

      sample identification by arrangement into  convenient groups.

            In brief,  a fair degree  of operator  skill  and knowledge,

      together with  adequately detailed  instructions,  is required  for

      successful automated analysis."

      In the report  "Compilation of  Methodology  For  Measuring  Pollution Parameters

of Landfill Leachate" by E.S.K. Chian and F.B. DeWalle,  the  following  comments

are made concerning  automated  methods:

            "All automated methods as recommended by EPA (1974)  for water

      and wastewater and Technicon  (1973)  for industrial waste should

      be evaluated for possible interferences since  most tests are

      based on colorimetric analyses which are generally subject  to

      strong interference  by  the color and  suspended solids present in

      leachate.  Such evaluation is  necessary since  increasing amounts

      of leachate samples will be analyzed by automated methods at a future


      Laboratory Quality Control

      The subject of laboratory quality control  is  treated in detail in "Hand-

book For Analytical Quality Control in Water and Wastewater Laboratories",


U.S. EPA  Technology  Transfer,  June 1972.   The  various  topics covered include:
Importance  of Quality  Control, Laboratory  Services,  Instrumental Quality
Control,  Glassware,  Reagents,  Solvents  and Gases,  Control of Analytical
Performance, Data  Handling and Reporting,  Special  Requirements for Trace
Organic Analysis and Skills and Training.   A number  of valuable references
are provided in each section.   Chapter  1,  Importance of Quality Control is
reprinted below:
                       (pp. 8-47, 8-48,  8-49)

      The technical  and  legal  aspects of an adequate quality control program
are of prime importance  in the analysis of sanitary  landfill Jeachate samples.
The investment of  time and effort needed for a quality control program are
well compensated in  the  resultant reliability  of and confidence in the data

                                       Chapter 1

                          IMPORTANCE OF QUALITY CONTROL
 1.1 General
The role of the analytical laboratory is to provide qualitative and quantitative data to be
used in decision making.  To be valuable, the data must accurately describe the character-
istics or the concentration of constituents in the sample submitted to the laboratory. In
many  cases,  an approximate  answer or incorrect  result  is worse than no answer at all,
because it will lead to faulty interpretations.

Decisions made using water and wastewater data are far-reaching. Water quality standards
are set to establish satisfactory conditions for a given water use. The laboratory data define
whether that condition is being met, and whether the water can be used for its intended
purpose. If the laboratory results indicate a violation of the standard, action is required on
the part of pollution control  authorities. With the  present emphasis on legal action and
social pressures to  abate  pollution, the analyst should be  aware of his^responsibility to
provide laboratory results that are a reliable  description of the sample. Furthermore, the
analyst must be aware that his professional competence, the procedures he has used, and the
reported values may be used and  challenged in court. To satisfactorily meet this challenge,
the laboratory  data  must  be backed up by an adequate program to  document the proper
control and application of  all of the factors which affect the final result.

In wastewater analyses, the laboratory  data define the treatment plant influent, the status
of the steps in  the treatment process, and the final load imposed upon the water resources.
Decisions on process changes, plant modification, or even the construction of a new facility
may be based upon the results of laboratory analyses. The financial implications alone are
significant reasons for extreme care in analysis.

Research investigations in  water pollution control rest upon a firm base of laboratory data.
The final result sought can usually  be  described in numerical terms. The progress of the
research  and the alternative pathways  available  are generally  evaluated  on  the  basis of
laboratory  data. The value of the  research  effort  will depend upon  the validity of the
laboratory results.

1.2 Quality Control Program

Because  of the importance of laboratory analyses and  the resulting actions wliich  they
produce, a program to insure the reliability of the data is essential. It is recognized that all
analysts practice quality control to varying degrees, depending somewhat upon their train-
ing, professional pride, and awareness of the importance of the work they are doing. How-
ever,  under the pressure of  daily  workload, analytical quality  control may be easily
neglected. Therefore, an established, routine control program applied to every analytical test
is important in assuring the reliability of the final results.

The quality control program in the laboratory has two primary functions. First, the program
should monitor the reliability (truth) of the results reported. It should continually provide
an answer to  "How good (true) are the results  submitted?" This phase may be termed
"measurement of quality." The second  function is the control of quality in order  to meet

the program requirements for reliability.  For example, the processing of spiked samples is
the measurement of quality, while the use of analytical grade reagents is a control measure.
Just as each analytical method has a rigid protocol, so the quality control associated with
that test must also involve definite required steps to monitor and assure that the result is
correct. The steps in quality control will vary with the type of analysis. For example, in a
titration, standardization of the titrant on a frequent basis is an element of quality control.
In an instrumental method, the check-out of instrument response and the calibration of the
instrument  in  concentration units is also  a  quality control  function. Ideally, all of the
variables which can affect the final answer should be considered, evaluated, and controlled.

This handbook considers the factors which go into creating an analytical result, and provides
recommendations for  the control of these factors in order to  insure that the best possible
answer is obtained. A  program based upon these recommendations will give the analyst and
his supervisor  confidence  in the reliability and the representative nature of the sample
characteristics being reported.

Without exception, the final responsibility for the reliability  of the analytical results sub-
mitted rests with the Laboratory Director.

1.3 Analytical Methods

In general, the widespread use of an analytical method indicates that it is a reliable means of
analysis, and this fact  tends to support the validity of the test result reported. Conversely,
the use of a little-known technique forces the data user to place faith in the judgement of
the analyst. When the analyst uses a "private" method, or one not commonly accepted in
the field, he must stand alone in defining both his choice of the method  and the result

The need  for  standardization  of methods within a single laboratory is readily apparent.
Uniform methods between cooperating laboratories are also important in order to remove
the methodology as a variable in  comparison or joint use of data between laboratories.
Uniformity of methods is particularly important when laboratories are providing data to a
common data bank, such as STORET*, or when several laboratories are cooperating in joint
field  surveys. A  lack of standardization of methods raises doubts as to the validity of the
results reported. If the same  constituent is measured by different analytical procedures
within  a single laboratory, or in several laboratories, the question is raised as to which
procedure is superior, and why  the superior method is not used throughout.

The physical and chemical methods used should be selected by  the following criteria:

    a. The method should measure the desired constituent  with  precision  and accuracy
        sufficient  to meet the data  needs in the  presence of the interferences normally
       encountered in polluted waters.

    b. The procedure should  utilize the equipment and skills normally available in  the
        average water pollution control laboratory.
 *STORET  is the acronym  used to identify  the  computer-oriented U.S.  Environmental
  Protection Agency Water Quality Control Information System for STOrage and RETrieval
  of data and information.

      c.  The selected methods should be in use in many laboratories or have been sufficiently
         tested to establish their validity.

      d.  The method should be sufficiently rapid to permit routine use for the examination
         of large numbers of samples.

  The use of EPA methods in all EPA laboratories provides a common base for combined data
  between  Agency programs. Uniformity throughout EPA lends considerable support to the
  validity of the results reported by the Agency.

  Regardless of the analytical method used in the laboratory.the specific methodology should
  be carefully documented.  In some water pollution  reports it is customary to state that
  Standard Methods (1) have been used throughout. Close examination indicates, however that
  this is  not strictly true. In many laboratories, the standard  method has been modified
  because of recent research  or personal preferences of the laboratory staff. In other cases the
  standard method has been  replaced with a  better one. Statements concerning the methods
  used jn arriving at laboratory data should be clearly and honestly stated. The methods used
  should be adequately referenced and the procedures applied exactly as directed.

  Knowing  the  specific method which has been used, the reviewer can apply the  associated
  precision  and accuracy of the method when  interpreting  the laboratory results  If  the
  analytical methodology is in doubt, the data user may honestly inquire as to the reliability
  of the result he is to interpret.        '                                               '

  The advantages  of strict adherence to accepted methods should not stifle investigations
  leading  to improvements in analytical  procedures. In spite  of the value of accepted and
  documented methods, occasions do arise when a procedure must be modified to eliminate
  unusual interference, or to  yield increased sensitivity. When modification is necessary the
  revision should be carefully worked out to accomplish the desired result. It is advisable to
  assemble data  using both the regular and the modified procedure to show the superiority of
  the latter. This useful information can be brought to the attention of the individuals and
 groups responsible  for methods  standardization. For  maximum  benefit,  the  modified
 procedure should be rewritten in the standard format so that the substituted procedure may
 be used throughout the laboratory for  routine examination of samples. Responsibility for
. the use of a non-standard procedure rests with the analyst and his supervisor, since such use
 represents a departure from accepted practice.
 In  field  operations, the problem of transport of samples to the laboratory, or the need to
 examine a large number of samples to arrive at gross values will sometimes require the use of
 rapid  field methods yielding approximate  answers. Such methods should be  used with
 caution, and  with a clear  understanding that the results obtained do not compare in relia-
 bility  with those obtained using standard laboratory methods.  The fact that "quick and
 dirty  methods have been used should be noted, and the results should not be reported along
 with more reliable laboratory-derived analytical information. The data user is entitled to
 know that approximate values have been obtained for screening purposes only, and that the
 results do not represent the customary precision and accuracy obtained in the laboratory.

 1.4  References

 1.  Standard Methods for the Examination of Water and Wastewater,  13th Edition  Amer-
    ican Public Health Association, New York (1971).

      The  economics  of  quality  control Is  greatiy  favored in the use of

automated  analysis systems  as compared to  manual systems.  In a recent

issue of the  U.S. EPA Analytical Quality Control Newsletter (October 1975,

p. 5), it  is  stated  that  for a  particular  automated system, the additional

personnel  work  load  required to provide an analytical quality assurance

overhead of 40%, is  estimated to be  about  1%.  The 40 to 1 advantage is

most impressive.  The newsletter article is reprinted below:

                         (p. 8-51)

                                             '• .   •'         .--'-.:  :•• .-'.-.
                                     5         . •   '      •/:"--••,-•

           -   .'.'-.:•  .  AUTOMATED QUALITY ASSURANCE     "   ..."   .';"•"
                '  "-":' J :' ."...    . '  -         .. '•   .     '  ".  '     >  ''"'.  -   .
 In a  number  of progress reports on the Laboratory Autoaation  System in this	
 Newsletter,  it was pointed out that one of the goals of the project was a"       ''1. '.-.
 significant  improvement in'analytical quality assurance  techniques.  Results      '•-•;.-
 obtained since installation 'last May have led us  to the  conclusion  that a '      .  V; -
 quality assurance high as 40% may be  accoccodated in  many analyses     _' -
 with  a nominal increase in. personnel workload.*         -••»-'    • "  •t./TVi*"^ .-"•• .-;'".f.-':
                -..,:.   -."•"•  «   .--  •-  > -  '<•• '>"».•->  -  --;-:•••-•• -.-'•'3-Sisj '-*•*!-"->•"^'"' :-'  -—.-'--"O
                  •?»•-?.<:^--^ ?--.--• ----.flp-r ^.**v:..-:-.--  - :•-.  -• --.^^.v^y-? :;•-•:-. v>.
 Quality assurance overhead is defined as the percentage of analytical measure-     - -
    ._ _  _ j_ _»_t_ _ A- -«	*. 	~»_~__~_^_.    * - -   - - *- — * J«k*d»   l*«>^  A«+fiA^» f»^»%my^ rf^tt ^*r%T% fr T*^% 1
- 1 •••'•
 ments made that do not generate environmental  data,  but either provide control  '..^;"
 information to the operator, or assure Better  overall quality of data.  Check   ,_.'„;_;..
 standards, spikes; replicates, blanks, reagent blanks, and calibration standards"-.-.•.""-•
 all contribute to this, overhead: .  ^.-.V/Mv " V-u.-.f=.-.  .j •-.-:'..''",''  3.""i^*0."-5^?!'".•-- V'.^i-t"''''
 AQC OVERHEAD = S™°£ Blanks * Replicates »  Spikes * Standards x'ipO.f ":|^.  '  ' 7.? >
          ;    .-/•-•.JU'."'.-'  ;i;-Sum of All Measurements 'Made    ^    ^ ;._^_ ^'^5.-'^ 1  r.j::'J.;-
 Check standards, "replicates,"and  spikes  should be measured at regular intervals   "-
 during the analysis of a series of environmental samples.  The results of. these   _  •-;.
 sieasurements should be compared with historical data for that operator and  that.  .'.  ,
 nethod, and the information.used  to determine whether the_analytical procedure
 is in or out of control.', " *•  \ '^':  "^:--.y^'^  -  - -^-."._;;^^^^' ^fr'r>'{*&&

 Calibration standards, baseline blanks,  and reagent blanks should be'measured  "" j"
 to assure better overall quality  in the. data.  Clearly the more calibration    j "
•standards"T:he "better'the definition-of-the working calibration curve over  a".  :.~. -'
 wider dynamic range.'• No assumptions of'linearity need be made.  Similarly,    .'!•_..•
 frequent checks of baseline blanks are checks on baseline drift and no assump-   "'..,
 tions of'quiet baseline'need be made.   Frequent checks of reagent blanks-assure ^-j^;;
 that no reagent contamination, is  a source of error. . All AO.A overhead measure- V"'..-,
 sients contribute to cost in  a  manual' system'since each involves the attention     /..
 of personnel and time for calculations,.   Often quality assurance overhead is " .._- '^
 simply deleted to improve environmental  sample throughput and reduce costs.
 With the on-line, real time  laboratory automation system, all of the above     JlT-"".,'
 quality assurance overhead has been fully integrated  into the programs  for     "_•
 operation of several instruments.  In  the specific case of the Technicon Auto
 Analyzer, the additional personnel workload required  to provide an AQA overhead
 of 40% is estimated about 1%. This consists largely of the time ^required   '
 to prepare spikes, blanks, and additional standards,  and include them  in the
 analytical sequence.  At the end  of a  series of measurements the instrument
 operator devotes very little tine to data evaluation.  Output reports  contain
 clear presentations of all quality assurance information and the frequent time
 wasted because of uncertainties about  the quality of  the data is eliminated.
 (Bill Budde, 513-684-2918)                •   :  '."'.•  '    - '.    "     'V-; VO^'A;.   ~'l*:'\


       Manpower and Skill Requirements

       Manpower and skill requirements for analytical work are dependent

 upon a number of factors, including nature of the sample,  work load,

 analytical parameter to be tested, method used,  sensitivity, precision

 and accuracy desired and equipment and facilities available.  A considera-

 tion of major importance, of course, is whether  the analyses will be performed

 by  manual or automated methods.

       In "Handbook For Analytical Quality Control In Water and Wastewater

 Laboratories",  U.S.  EPA, June 1972, pp.  9-2,  9-3,  9-4, skills and skill-time

 ratings for standard manual  analytical operations  are discussed in detail.

 A reprint of this section is  given below:  pp.  8-53,  8-54, 8-55.

      Manpower  and skill requirements  are  reduced  dramatically when automated

methods  are used.  The usual  skill requirements are  those of a technician

 for preparation of samples, solutions,  calibration and glassware handling.

Automated data  processing affords  additional manpower savings.

9.2 Skills                              :

The  cost  of data production in the analytical laboratory is based largely upon two
factors-the  pay scale of the analyst, and the number of data  units produced per unit of
time. However, estimates of the number of measurements that can be made per unit of time
are difficult, because of the variety of factors involved. If the analyst is pushed to produce
data at a  rate beyond his capabilities, unreliable results may  be produced.  On the other
hand, the analyst should be under some compulsion to produce a minimum number of
measurements per unit of time, lest the cost of data production become prohibitive. In the
following  table,  estimates are given for the  number of  determinations that an analyst
should be expected to perform on a routine basis. The degree of skill required for reliable
performance is also indicated. The arbitrary rating numbers for the  degree of skill required
are footnoted in the tables, but are explained more fully below:

    a.   Rating  1-indicates an  operation  that can be  performed by  a semi-skilled
        sub-professional with limited background; comparable to GS-3  through GS-5.

    b.   Rating  2-operation  requires  an  experienced   aide (sub-professional)   with
        background in general laboratory technique and some knowledge of chemistry, or a
        professional  with modest training and experience; comparable  to  GS-4 through

    c.   Rating 3-iridicates a complex procedure requiring a good background in analytical
        techniques; comparable to GS-7 through GS-11.

    d.   Rating  4-a  highly  involved  procedure  requiring  experience  on  complex
        instruments; determination requires specialization by analyst who interprets results;
      . comparable to GS-9 through GS-13	-	-     -  	   -

The time limits presented in the table are  based on use of EPA methods.
A tacit assumption  has been  made that  multiple analytical units  are  available  for
measurements requiring special equipment, as for cyanides, phenols, ammonia, nitrogen and
COD. For some of the simple instrumental or simple volumetric measurements, it is assumed
that other operations such as filtration, dilution or duplicate readings are required; in such
cases the  number of measurements performed per day  may appear to be fewer than one
would  normally anticipate.

                                    Table 9-1

       Measurement          Skill Required (Rating No.)           No./Day
       Turbidity (HACK 2100)
       DO (Probe)
       Fluoride (Probe)
(Simple Instrumental)

 (Simple Volumetric)
       Alkalinity (Potentiometric)
       Acidity (Potentiometric)
       DO (Winkler)
       Solids, Suspended
       Solids, Dissolved
       Solids, Total
       Solids, Volatile
       Nitrite N (Manual)
       Nitrate N (Manual)
       Sulfate (Turbidimetric)
 (Simple Gravimetric)
(Simple Colorimetric)
1 -  aide with minimum training, comparable to GS-3 through GS-5
2 -  aide with special training or professional with minimum training,
     comparable to GS-5 through GS-7.
3 -  experienced analyst, professional, comparable to GS-9 through GS-12.

                       Table 9-1 (continued)
    Skill Required (Rating No.)
(Complex. Volumetric or Colorimetric)
 Phosphorus, Total
 Phenol (Dist'n only)
 Oil & Grease (Soxhlet)
 Fluoride (Dist'n)
             2,3    .
       (Special Instrumental)





 Metals by AA
 (No preliminary treatment) .
 Metals by AA  '          .2,3
 (With preliminary treatment)
 Pesticides by GC                 3,4
 (Without cleanup)
 Pesticides by GC                 3,4
 (With cleanup)

 2 -  aide  with  special  training  or professional  with minimum  training,
      comparable  to GS-5 through GS-7.
 3 -  experienced analyst, professional, comparable to GS-9 through GS-12.
 4 -  experienced analyst, professional, comparable to GS-11 through GS-13.
  * -  depends on type of sample.                      .       .      .".. ..

Table 3. With automation. 3 people can handle three times the workload formerly handled by 12 people at
Distilled fluoride '
.Distilled cyanide
Distilled phenol
Total phosphorus
-. " " "'
. Number ptr hour
-•••" .3-4 : --•
I' "-1-2 - '.'
•/ 3-4 ' -
- ;•; 6-8 .
'. ' '-is-is:' .- •
*;' • 10^12 . • '
10-12 ".
, ' 13-16'est.
10-13 '
5-7 ;
• -: 13-16
Manuel Me
- - Bench space
__ required
• - '• 10ft
" 15ft '
.- '.- 10 f I
" / " 5 r* -
••" ' 20 ft"
- ' * <- .
':- 5 ft

1 .
' '.' 1
'- . - ' 1 '
1 -
-,•'• I .
1 -.;" "
' '- . 1
. 1
Automated Method
per hour

45 .
Bench space)

15 ft

' 1 -"•
t -.

45 ft
  " Source—Handbook for Anilylieil Quality Control In Water and Waslewiler Laboritorlti E!.P A » Includes "mP!|P'«£
cOne technician needed to prepare samples and glassware. t/AutoAnalyzer Unit can be used for o.her analyses. Source
Association. Floyd D. Kefford.       ,                                                                 _
          Water Works
932  Environmental Science & Technology

      A comparison of manual versus automated analytical methods for

throughput, space and personnel requirements is given in "Automated

Methods For Assessing Water Quality Come Of Age", by M.J.F. Du Cros and

J. Salpeter,  Environmental Science and Technology, Vol. 9, Number 10,

Oct. 1975, p. 932.  See Table No.  3 below  (p.8-57).

      Data are presented in tabular form for the analysis of 12 water

quality parameters.  For the manual methods, 12 personnel and 114-feet  of

bench space are  required to perform 100 to 126 determinations per hour.

For the automated methods, 3 personnel and 45-feet of bench space are

required  to perform 370 determinations per hour.  In addition to an

appreciable savings of  space,  the automated  throughput  is  approximately

12  times  that achieved  with manual methods.

Records,  Data Handling  and Reporting

     A  significant  amount  of  analytical data are  generated in a leachate

testing program. The data must be handled,  interpreted, checked of validity,

recorded  and reported.   This  is an important aspect  of  the testing program

and should be given appropriate attention. If  the data  are not  properly

handled,  the considerable  effort and  expense involved in sampling and  analysis

can be  lost or  applied  wrongly.  It  should be  noted  that legal, as well as

technical considerations  can  be associated with  records, data handling and


     Reprinted  below  is Chapter 7, pp.  7-1 to  7-11,  entitled "Data Handling

and Reporting",  fron  Handbook for Analytical Quality Control In Water  and

Wastewater Laboratories,  U.S.E.P.A.,  June  1972.   Among  the topics  treated

in  this chapter are:  Significant Figures, Accuracy  Data,  Precision Data,

Report  Forms, Digital Read-Out, Key  Punch  Cards  and  Paper  Tape, Storet Com-

puterized Storage and Retrieval of Water  Quality  and Data  and SHAVES - a

Consolidated Data Reporting and Evaluation System.


                                     CHAPTER 7

                          DATA HANDLING AND REPORTING
7.1  Introduction

To  obtain  meaningful  data on  water  quality,  the  laboratory  must  first collect  a
representative sample and deliver it unchanged for analysis. The analyst must then complete
the proper analysis in the prescribed fashion. Having accomplished these steps, one other
important  step must be  completed before the data are of use. This  step  includes the
permanent recording of the analytical data in meaningful, exact terms, and reporting it  in
proper form to some storage facility for future interpretation and use.

The brief sections that follow discuss the data value itself, recording and reporting the value
in the proper way, means of quality control of data, and storage and retrieval.

7.2 The Analytical Value

7.2.1  Significant Figures

The term significant figure is used rather loosely to describe some judgment of the number
of reportable digits in a  result. Often the judgment is not soundly based  and meaningful
digits are lost or meaningless digits are accepted.

Proper use of significant figures gives an  indication of the reliability of the analytical
method used. The following definitions and rules are suggested for retention  of significant

A number is an expression of quantity. A figure or digit is any of the characters 0,1, 2, 3, 4,
 5, 6, 7, 8, 9, which, alone or in combination, serves to express a number. A significant figure
 is'a digit that denotes the amount of the quantity in the place in which it stands.

Reported  values should contain only significant figures. A value is made up of significant
 figures when it contains all digits known to be true and one last digit in doubt. For example,
if a  value is reported as 18.8 mg/1, the  "18"  must be firm values  while the  "0.8   is
somewhat uncertain and may be "7" or "9".

 The number zero may or may not be a significant figure:

     a.   Final zeros after a decimal point  are always significant figures. For example,  9.8
         grams to the nearest mg is reported as 9.800 grams.

     b.  Zeros before a decimal point with other preceding digits arc significant. With no
         other preceding digit, a zero before the decimal point is not significant.

     c.  If there are no digits preceding a decimal point, the zeros after the decimal point
         but preceding other digits are not significant. These zeros only indicate the position
         of the decimal point.

     d.   Final zeros in a whole number may or may not be significant. In a conductivity
         measurement of 1000 /imhos/cm, there is no implication that  the conductivity is
         1000 ± 1 pmho. Rather, the zeros only indicate the magnitude of the number.

 A good measure of the significance of one or more zeros before or after another digit is to
 determine whether the zeros can be dropped by expressing the number in exponential form.
 If they  can, the zeros are not significant. For example, no zeros can be dropped when
 expressing a weight of 100.08 grams in exponential form; therefore the zeros are significant
 However, a weight  of 0.0008 grams can be expressed in exponential form as 8 x IO'4 grams!
 and the zeros are  not significant. Significant figures reflect the limits of the  particular
 method of analysis. It must be decided beforehand  whether this number of significant digits
 is sufficient for interpretation purposes. If not, there is little that can be done within the
 limits of normal laboratory operations to improve these values. If more significant figures
 are needed, a  further improvement in method  or selection of another method will  be
 required to produce an increase in significant figures.

 Once the number of significant figures is established for a type of analysis, data resulting
 from such analyses are reduced according to set rules for rounding off.

 7.2.2 Rounding Off Numbers

 Rounding off of numbers is a necessary operation in all analytical areas. It is automatically
applied by the limits of measurement of every instrument and all glassware. However, it is
often applied in chemical calculations incorrectly by blind rule or prematurely, and in these
instances, can seriously affect the final results. Rounding off should  normally be applied
only as follows: Rounding-Off Rules

    a.   If the figure following those to be retained is less than 5, the figure is dropped, and
        the retained figures are kept unchanged. As an example: 11.443 is rounded o'ff to

    b.   If the figure following those to be retained is greater than 5, the figure is dropped,
       and the last retained figure is raised by 1. As an example: 11.446 is rounded off to

    c.  When the figure following those to be retained is 5, and there are no figures other
       than zeros beyond the 5, the figure is dropped, and the last place figure retained is
       increased by 1 if it is an odd number, or it is kept unchanged if an even number. As
       an example: 11.435 is rounded off to 11.44, while 11.425 is rounded off to 11.42. Rounding Off Single Arithmetic Operations

   a.  Addition: When adding a series of numbers, the sum should be rounded off to the
       same numbers of decimal places as the addend  with the smallest number of places.
       However, the operation is completed with all decimal places intact and rounding off
       is done afterward. As an example:
                                         33.35 The sum is rounded off to 33.4.

     b.   Subtraction:  When subtracting one number from another, rounding off should be
         completed  before the  subtraction operation,  to avoid invalidation of the whole

     c.   Multiplication:  When two numbers of unequal digits are to be multiplied, all digits
         are carried through the operation, then the product is rounded off to the number of
         significant digits of the less accurate number.

     d.   Division: When two numbers of unequal digits are to be divided, the division is
         carried out on the two numbers using all digits. Then the quotient is rounded off to
         the number of digits of the less accurate of the divisor or dividend.

     e.   Powers and Roots: When a number  contains n significant digits, its root can be
         relied on for n digits, but its power can rarely be relied on for n digits. Rounding Off the Results of a Series of Arithmetic Operations

 The rules  for rounding off are reasonable for simple calculations, however, when dealing
 with two nearly equal numbers, there is a danger of loss of all significance when applied to a
 series of computations which rely on a relatively small difference in two values. Examples
 are calculation of variance and standard deviation. The recommended procedure is to cany
 several extra figures through the calculation and then to round off the final answer to the
 proper number of significant figures.

 7.2.3 Glossary of Terms

 To clarify the meanings of reports and evaluations of data, the following terms are defined.
 They are derived in part from American Chemical Society and American Society for Quality
 Control usage (1,2).  Accuracy Data

 Measurements which relate to the difference between the average test results and the  true
 result when the latter is known or assumed. The following measures apply:

        Bias is defined as error in a method which systematically distorts results. The term
        is used interchangeably with accuracy in that bias is a measure of inaccuracy.

        Relative error is the mean error of a series of test results as a percentage of the  true
        result. Average

In ordinary usage, the  arithmetic mean. The arithmetic mean of a set on _n_values is the  sum
of the values divided by.n. Characteristic

A property that can serve to differentiate between items. The differentiation may be either
quantitative (by variables), or qualitative (by attributes).

------- Error

The difference between an observed value and its true value. Mean

The sum of a_series of test results divided by the number in the series. Arithmetic mean is
understood (X). Population

Same as Universe. (See subparagraph Precision

Degree of mutual agreement among individual measurements. Relative to a method of test,
precision is the degree of mutual agreement, among individual measurements made under
prescribed, like conditions. Precision Data
Measurements  which relate  to  the variation  among the test results themselves, i.e., the
'scatter or dispersion of a series of test results, without assumption of any prior information.
The following measures apply:

    a.  Standard Deviation (a).  The square root of the variance.
                                   a  -  w 1=1        Y 2

    b.  Standard Deviation, estimate of universe (s).
    c.  Coefficient  of Variance (V)._The ratio of the standard  deviation (s) of a set of
        numbers, n, to their average, X, expressed as a percentage:

    d.  Range. The difference between the largest and smallest values in a set.

    e.  95% Confidence Limits. The interval within which one estimates a given population
        parameter to lie, 95% of the time.

------- Sample

A group of units, or portion of material, taken from a larger collection of units, or quantity
of material, which serves to provide information that can be used as a basis for judging the
quality  of the  larger quantity  as a basis for action on  the  larger  quantity  or on  the
production process. Also used in the sense of a "sample of observations."  Series

A number of test results which possess common properties that identify them uniquely.  Skewness(k)

A  measure of the lopsidedness  or asymmetry  of a  frequency  distribution defined by the

                                    (Xj  -X)3
This measure is a pure signed number. If the data are perfectly symmetrical, the skewness is
zero. If k is negative, the long  tail of the distribution is to the left. If k is positive, the long
tail extends to the right. Unit

An object on which a measurement or observation may be made. Universe

The totality of the set of items, units, measurements, etc., real or conceptual, that is under
consideration. Variable

A term used to designate a method of testing, whereby units are measured to determine, and
to record for each unit, the  numerical magnitude of the characteristic under consideration.
This involves reading a scale of some kind.

7.3 Report Forms

The analytical information reported should include the parameter, the details of the analysis
such as burette readings, absorbance, wavelength, normalities of reagents, correction factors,
blanks, and finally, the reported value.

To  reduce  errors in manipulation of numbers, a good general  rule is  to keep data
 transposition to an absolute minimum. If this were pursued,  the ideal  report form would
 include all  preliminary information  of the analysis, yet it would be possible to use the same
 form  through to the final  reporting of  data  into a computer  or other storage  device.
However, the ideal report form is not usually in use. Rather, a variety of methods are used to
record data. They are:

7.3.1 Loose Sheets

Reporting of data onto  loose or ring-binder forms is an older, but much used means of
recording data.  It  does allow  easy  addition of new sheets, removal of older data,  or
collection of specific data segments. However, the easy facility for addition or removal also
permits easy loss or misplacement of  sheets, mix-ups as to date sequence, and questionable
status in formal display, or for presentation as evidence.

7.3.2 Bound Books

An improvement in data recording is use of bound  books which force the sequence of data
insertion. Modification beyond a simple lined book  improves its effectiveness with little
additional effort. Numbering  of pages encourages  use  in  sequence and  aids  also in
referencing  data, through a table of contents, according to time, type of analysis,  kind of
sample, analyst, etc.

Validation can be easily accomplished by requiring the analyst to date and sign each  analysis
on the day completed. This validation can be strengthened further by providing space for
the laboratory supervisor to sign off as to the date and acceptability of the analysis.

A  further  development of the bound  notebook is the  commercially available  version
designed for  research-type work.  These note books  are preprinted  with book and page
numbers and  spaces for title of project, project number, analyst signature, witness signature
and dates. Each report sheet has its detachable duplicate sheet which allows for up-to-date
review by management without disruption of the book in the laboratory. The cost  is about
four times that of ordinary notebooks.

Use of bound notebooks is essentially limited to research and development work where an
analysis is part of a relatively long project, and where the  recording in the notebook is the
prime disposition of the data until a status or final report is written.

 7.3.3 Pre-Printed Report Forms

Most  field laboratories or other installations doing repetitive analyses for many parameters
day in and day out, develop their own  system of recording and tabulating laboratory data.
This may include bound  notebooks; but a vehicle for forwarding data is also  required. In
 many instances, laboratory units tailor a form to fit a specific group of analyses, or to report
 a single type of analysis for series of samples,  with as much information as  possible
 preprinted  to simplify use of the form. With loose-sheet multicopy forms (use of carbon or
 NCR  paper) information  can be forwarded  daily,  weekly, or on  whatever schedule  is
 necessary  while allowing retention  of all data in the laboratory. Still, the most  common
 record is 'an  internal bench sheet, or bound book, for recording of all data in  rough form.
 The bench sheet or book never leaves the laboratory but serves as the source of information
 for all subsequent report forms (See Figure 7-1).

 In most instances the supervisor and analyst wish to look at the data from a sample point in
 relation to other sample points on the river or lake. This  review of data by  the supervisor,
 prior to release, is  a very important  part of the laboratory's quality control  program;
 however, it is not easily accomplished with bench sheets. For this purpose, a summary sheet
 can be prepared which compares a related group of analyses from a number of stations. An
 example is shown in Figure 7-2. Since the form contains all of the information necessary for

                                             ' Figure 7-1.  EXAlv     3F 13ENCH SHEET
      Spcctrographic Analyses Bench Data

      Sample #	Date	Source.
                                     Test Count
                   ml. cone. to.
ml. Factor
1. Zn
2. Cd
r Ac
d. R
«; p
fi Fe
7 Mn
R, Mn
0 Al
1 n III-.
1 ' , <"»
19 Ac
P Nj
14 Co
i <; Ph
16 Tr
]7 V
18. Rn
1Q. Sr
Rerun Count

Av. In Cone. Less Orig.
Count Sample Than Sample

! — i
1 ;

1 1 !


1 I
1 1 !
1 1
1 i
1 1
1 „
1 1
1 I
n r
I i
i i
i „
[— i r

I i
i „


Ohio at Ironton
Ohio at Greenup Dam
Ohio at Portsmouth
Scioto at Lucasville
Ohio at Maysville
Ohio at Meldahl Dam
Little Miami at Cincinnati
Ohio at Cincinnati
Licking at 12th Street
Ohio at Miami Fort
Ohio at Markland Dam
Kentucky nt Dam I
Ohio at Madison
Great Miami at Eldcan
Great Miami at Scllars Road
Great Miami at Liberty-
Fairfield Road
Great Miami at American
Materials 8 ridge
Whitewater at Suspension
Great Miami at Lawrenceburg
(Lost Bridge)












reporting  data  it is used  also to complete the data forms forwarded to the storage  and
retrieval system.

The forms used to report  data to data storage s>stems require a clear identification of the
sample point, the parameter code, the type of analysis used, and the reporting terminology.
Failure to provide the correct information can result in rejection of the data, or insertion in
an incorrect parameter. As a group of analyses is completed on one or more samples, the
values are reported in floating decimal form, along with  ihe code numbers, for identifying
the parameter and the sampling point (station). Figure 7-3 shows an example of a preprinted
report form for forwarding data to keypunch.

7.3.4 Digital Read-out

Instrumental  analyses, including automated, wet-chemistry instruments, such as Technicon
AutoAnalyzer,  atomic absorption spectrophotometer. pH meter, selective electrode meter,
etc., now  can provide direct digital readout of concent rat ion, which can be recorded directly
onto report sheets without  further calculation.  Electronics  manufacturers now produce
computer-calculators that will construct best-fit curves. Integrate curves, and/or perform a
pre-set series  of calculations required to obtain the final reported value for recording by the

7.3.5 Key Punch Cards and Paper Tape

Since much of the analytical data  generated in laboratories  is recorded on bench sheets,
transferred to  data  report  forms, key-punched,  then manipulated  on small  terminal
computers, or manipulated  and stored in a larger data storage system, there is a built-in
danger of transfer error. This increases with each  transposition of data. It is suggested that
the analyst can reduce this error by recording data onto punch cards directly from bench
sheets. The cards can be retained, or forwarded immediately to the data storage  system  as
desired. IBM now offers a small  hand-operated key-punch for this purpose.

It is anticipated that in future water quality systems, the intermediate report sheers will be
eliminated and the data will be punched  automatically by the analytical instrument system
onto key-punch cards and/or paper tapes for direct use as computer input.

7.4 STORET-Computerized Storage and Retrieval of Water Quality Data

The use of computers  with their almost unlimited ability to record, store, retrieve, and
manipulate  huge  amounts  of  data is a natural  outgrowth of demands for meaningful
interpretation of the great masses of data generated in almost any technical activity.

In August 1961, an informal conference was held in  the  Basic Data Branch, Division  of
Water  Supply and  Pollution Control, U.S. Public Health Service. A number of ideas were
brought together in the basic design of a system for storage and retrieval of data for water
pollution  control, called STORET.  In 1966, the STORET system was transferred, with the
Division, into the Federal Water Pollution Control Administration. U.S. Department of the
Interior.  A  refinement   of  this system  is  now  operated  by the Technical  Data and
Information Branch, Division of Applied Technology. EPA.

If properly stored, the data can be retrieved according to the point of sampling, the date,
the specific parameters stored,  etc., or all data at a sample point or series of points can be

         Figure 7-3.  EXAMPLE OF STORE? REPORT FORM

»T «tiQN C
••-•"•• YN." "nVrVAY

•"" ,..,.

1 1 1
Fccil Coliform UMIT MF/100

i 1 | 1 1 | 1 1 1 III
.Tt^ Fecal Streptococci umr MF/100


ITfM _
1 1 1
•T*«.. .
1 1

1 1 j 1 1 1 1 1 1 III
NHrN + Org-N UM1T mg/1
11)111111 III
NHj-N UHIT mg/1
1 1 j 1 1 I 1 1 1 III
NOj-N * NOj-N UNIT mg/1
1 1 | 1 1 1 I 1 1 III
P. Total UNIT ms/l

1 1 } i 1 J 1 1 1 III
P, Soluble UNIT mg/1
1 1 J 1 1 J I--I 1 III
TOC urfiT ma/I
1 1 j 1 1 II 1 1 III
Phenol uniTUe/l
1 1 ] 1 1 1 1 | I ,|||
Cyanide ' UNIT mit/1
1 1 | 1 1 1 1 1 1 III
111 i i i i ; i
i : i
|3|<|6|l|6|| | | 1 1

h|.|6|7|9|| | | 1 1

|0|0|6|3|5|| | | | |


|0|0|6 3|0|| | | | 1
|0|0|6 6|5|| | | 1 1

|0|0|6|6|6|| | | | |

|0|0|6|8|0|| | | 1 1

|3|2|7|3|0|| 1 I I 1

Io|o|7h|o|| | | | |
• I.TI n->i

i : i
i : i
7i . H •• •*

extracted as a unit.

There is a  State/Federal cooperative activity which provides State water pollution control
agencies with direct, rapid access into a central computer system for the storage, retrieval,
and analysis of water quality control information.

Full details on  use of the STORET system are given in the STORET handbook recently
revised (3).

7.4 SHAVES-A Consolidated Data Reporting and Evaluation System

Information systems have been developed to bridge the gap between the analyst and his raw
data, and  a complex  data storage and control system.  These systems include preprinted
report  forms, computerized  verification,  and  evaluation of data and data storage. An
example is the SHAVES system.

The term,  SHAVES, is an acronym for "Sample Handling and Verification System," which
originated  at the Great  Lakes-Illinois River Basin Comprehensive Project Laboratory at
Grosse  Isle,  Michigan. Although  the system's  original purpose  was  verification of the
calculations  following laboratory  analyses, it  now includes  data  storage, checks for
completeness and consistency of data, procedures for submitting analytical requests, a set of
forms for recording sampling and analytical information, and a clerical procedure to account
for  analyses  completed  and  pending.  The  primary purposes  of SHAVES  are the
standardization, automation and control of reporting analyses. All samples received at the
Pacific  Northwest Water Laboratory for routine analysis are processed through the system.

Although SHAVES uses a computer to perform its operations, it is not primarily a computer
program.  It  is intended  for use as an intra-laboratory quality  control tool, and as such
compliments the STORET system. It is described in detail elsewhere (4).
 7.6 References

 1.   "Guide for Measure of Precision and Accuracy," Anal. Chem., Vol. 33, p. 480, (1961).
     p. 480.

 2.   "Glossary of General Terms Used in Quality  Control," Quality  Progress,  Standard
     Group of the Standards Committee, ASQC, II, (7), pp. 21-2, (1969).

 3.   Water Quality Control Information System (STORET), EPA, Washington, D.C. 20460,
     Nov. 15,1971.

 4.   Byram, K. V.  and Krawczyk, D. F.,  "An Evaluation of SHAVES: A Water Quality
     Sample Handling System," Environmental Protection  Agency, Pacific Northwest Water
     Laboratory, 1969.



For every landfill both existing and proposed, the necessity

of establishing a ground-water monitoring program should be

investigated.  The methodology to make this determination and,

if necessary, to define the  specifics of a monitoring program,

can be described in a logical sequence of individual steps.

Following the generalized steps ""presented in this chapter will

allow these determinations to be based on the proper factual

information.  As with any complex situation, however, original

thought will be required during each step to insure arriving

at the best possible answers.

The steps presented in this  chapter are intended to indicate

the logical progression of required efforts and therefore not

accompanied by detailed descriptions.  Such descriptions can

be found in other chapters of this manual or in the references

cited at the end of the appropriate chapter.


All the information would be gathered from an inspection of the

landfill, examination of landfill records and other existing

information such as topographic maps, and discussion with land-

fill operating personnel.  The purpose is to define, with a

mininum expenditure of time and money, the probable magnitude

of the ground-water contamination problem and thus the urgency

of conducting a detailed study and establishing a monitoring



The types of waste accepted or rejected varies widely from

landfill to landfill depending largely on the types of waste

generated in the area, the regulatory agency for the area, the

landfill operator, and economics.  A determination of the

types of wastes accepted at a particular landfill (both current-

ly and historically) is critical to the monitoring evaluation,

i.e., the contaminants likely to be present in the ground water.

Wastes can be generally categorized as follows:

  - municipal refuse  (paper, household garbage, leaves and

    grass, wood, synthetics, cloth, glass and metal)

  - bulky refuse  (tree stumps, car bodies, and demolition


  - municipal sewage sludge

  - industrial solid wastes  (defective raw materials and prod-

    ucts, packaging and scrap)

  - industrial chemical wastes  (liquid or solid)

  - industrial  sludge  or  residue  (fly  and bottom ash, waste

    water treatment  sludge  and  pollution control systems

    residue)                •''

  - chemical waste in  sealed drums  (of particular concern

    because of  delayed release  factor)

  - low level radioactive wastes  (contaminated laboratory

    equipment/  clothing and building debris)

The categories  which are  accepted at the landfill should be

determined and/ in the case of  Industrial wastes, more detailed

information should be  sought.


The size and thickness of a landfill are important factors in

establishing the volume of  leachate generated as well as the

concentration of contaminants in the leachate.  The areal ex-

tent of a landfill may be measured  directly or indirectly

from an accurate large scale map or aerial photograph.  In

addition, the extent of flat and sloping portions of the land-

fill should be  determined.   Landfill thickness may, in some

cases, be determined from a recent  topographic map or by

measuring the difference  in elevation  between the toe and top

surface.  If the landfill fills a depression, pre-landfilling

elevations of the base of the depression may be available,

otherwise one or more borings will have to be drilled through

the landfill to directly determine its thickness.


In most cases, refuse is compacted after it has been placed

in the landfill.  This is accomplished either by special equip-

ment or by the bulldozers used to spread and cover the refuse.

The method of in-place compaction should be determined to allow

estimates to be made of density and field capacity of the land-

fill.  In some cases refuse receives treatment prior to land-

filling.  Shredding and/or pre-disposal compaction and baling

of refuse will significantly increase its density and thus its

field capacity.  Incineration and resource recovery operations

will alter its composition and consequently change the nature

of the leachate generated after landfilling.  In addition, the

percentage of the total refuse received which is treated, the

types of refuse receiving treatment and the placement of the

treated and untreated refuse in the landfill should be deter-



The procedures used in placing and covering refuse at the land-

fill site will influence the volumes and characteristics of

leachate generated.  Such practices as separation of different

types of refuse at the landfill site, thickness of refuse

layers between cover layers, thickness of cover layers,  and

type of material used for cover will be of importance.   For
example, if chemical wastes are accepted at a landfill but

segregated from municipal refuse in one area, leachate gen-

erated within this chemical disposal area will follow a  flow
path which may be predictable and thus would influence  the

selection of monitoring points.  Thickness of refuse and

cover layers may affect volumes and characteristics of

leach'ate and would therefore also influence the design  of a

monitoring system.             ;


The rate at which the thickness of a landfill increases will

affect the volume of leachate generated since a thick section

of refuse can absorb more water  (field capacity) .  If the land-

fill thickness increases at a sufficient rate relative to pre-

cipitation, and is covered upon completion to exclude precipi-

tation, very little  leachate will be generated.  Thus, the rate

of filling will influence the design of a monitoring program.

The rates of increase  in thickness of various portions of the
landfill may be extraplated  from  the  records of weights  of
refuse  accepted over the  landfilling  period, if such records

are available.   If  not,  recollections of  landfill  operators re-

garding volumes of  refuse  accepted over  past years may  provide

 some useful information.

 Refuse layers of different ages produce leachates of different

 chemical characteristics.  This factor may be useful in design-

 ing a monitoring program; however, other factors, such as refuse

 composition have a more noticeable influence on leachate than

 does refuse age.


 A landfill equipped with an underliner and leachate collection

 system would be assumed not to be contaminating ground water

 and a monitoring system would be designed only to test the

 validity of this assumption.   Similarly, if the landfill were

 completed and covered to prevent the infiltration of precipita-

 tion, monitoring, at least initially, would be necessary only

 to establish if this were indeed the case.  If the liner or

 cover system was shown to be ineffective by initial monitoring

 data, an expanded monitoring program would be designed to define

 the extent of the problem and necessary corrective measures.

When analyzing the effectiveness of a bottom liner and collec-

 tion system, the volume of leachate actually collected should

 correspond to the predicted volume of leachate being generated.

With covers and surface drainage systems, runoff and evapo-

 transpiration accounts for a large percentage of precipitation.

Factors such as cover permeability, slopes and vegetation type

would be considered in this determination.


The primary purpose of this effort would be to establish

estimates of surface runoff and  infiltration patterns, and

general direction  of ground-water flow.  The topography of

the areas surrounding the landfill will establish the direc-

tion of surface-water flow, either towards or away  from the

landfill  surface.   Recharge and  discharge areas at  the site

can be determined  and, based  on_these,  the general  direction

of ground-water flow approximated.


A preliminary check into ground-water use in the  vicinity of

the  landfill should be made at this  time.  Simply ascertain-

ing  the  existence of supply wells in the vicinity of the land-

 fill is  sufficient for this step, with additional data regard-

 ing such wells obtained  as part of the next step.


 Once the need for a detailed  ground-water investigation and

 monitoring program has been established  (Step 1),  the program

 should be carefully planned.  To accomplish this task efficient-

 ly, all existing  pertinent data is gathered and examined  at the

 outset.  The data would  include all  information  from Step 1 and

any useful data available fron outside sources.   In addition,

certain data not gathered during Step 1,  but which can be
readily obtained at the site, e.g.,  analyses of  water samples

from existing wells, are now gathered.


Information which should be sought other than that gathered

in Step 1 includes:  historical precipitation records for the

site or a nearby area, geologic and topographic  maps which

include the landfill site, geologic logs of any  existing wells

or test borings at or near the site, and a recent aerial

photograph of the site from which to prepare an  accurate base

map.  In addition, if potential sources of contamination other

than the landfill are located in the vicinity, all available

information regarding these sources (type and volume of waste,

methods of disposal, etc.) should be collected and reviewed.


Additional data which will improve the efficiency of a hydro-

geologic investigation of a landfill  (Step 3) include:  analyses

of water samples from surface-water bodies and existing wells

located on or near the site;  analyses of samples of leachate

from surface seeps;  examination of site vegetation, by a

Dotpnist, for signs of stress;  observations of surface drainage

patterns during a rainfall;  and a check of building base-

ments and other subsurface structures at the site for landfill

gas accumulations.         ""

The most critical areas for monitoring in the vicinity of a

landfill will be where industrial, domestic, or public-supply

wells are threatened by leachate contamination.  In the pre-

vious step, a preliminary check of the number and location of

all such wells was made.  In addition to well locations, such

information as screened interval, pumping rates and periods of

pumping, as well as water use Should be compiled.  If possible,

•the size and shape of the cone of influence should be estimated

for each well located.  Historical water-quality data for the

wells, where available, should be examined and, where not

available or insufficient, water samples should be taken for


Many states and regional authorities have regulations regarding

minimum distances from landfills within which supply wells must

be monitored for contamination.  These regulations would have

to be followed, but the actual distance monitored should be

based on the results of a hydrogeologic investigation.  Con-

stituents determined in water-quality analyses should meet

applicable regulations and expanded, if necessary, based on

anticipated leachate characteristics and ultimate use of water

from each supply well.

 Besides  supply wells,  surface-water  use in the area must be
 considered.  Nearby  surface water may bo used for potable
 supply,  fishing or shellfishlng, swimming or other recreation,
 or wildlife habitat.   Surface-water  bodies are often discharge
 areas, and as such are subject to contamination from leachate
 in the ground-water  system.  'Such information as location, use
 and rate of flow for all surface-water bodies in the vicinity
 of a landfill should be established.  Natural water quality,
 existing contamination, and sources  of contamination should
 be investigated.  Surface-water bodies may form an important
 part of a monitoring program because, at discharge points,
 they are the places  where ground-water contamination is most


 Probably the most important factor in establishing the need
 for and design of a  landfill monitoring system is the hydro-
 geologic setting of  the landfill.  Such information as surficial
 and bedrock geology, depth to the water table and direction and
 rate of ground-water flow should be determined prior to se-
 lecting a landfill site.   In the past this has not been the
 case and landfills have been located primarily on land of low
economic value,  such as swamps or abandoned gravel pits.  In
such areas the ground-water pollution potential is high and
 the need for monitoring and abatement procedures is acute.


A survey of surficial geology should establish the areal extent

and thickness of the layers of various types of deposits under

and adjacent to the landfill, and the permeabilities and inter-

connections of these layers.  The survey can be divided into

three sequential parts:  1)  a review of geologic data gathered

during Steps 1 and 2;  2) geophysical surveys designed to fill

in missing subsurface information;  and 3) test drilling to

provide direct control for the geophysics, obtain more precise

data in critical areas, and allow detailed analyses of geologic



In some cases bedrock will act as a barrier to leachate move-

ment and in others leachate may move into bedrock aquifers.

The type of rock beneath the site and the amount of fracturing

will determine the role of bedrock in the movement of leachate.

Determination of bedrock geology will essentially follow the

steps outline for surficial geology.


The ground-water investigation  should be  designed to answer

such questions as depth to the water table, extent of ground-

water mounding caused by the landfill, natural flow direction

and rate, influence of the landfill on flow direction and

rate, locations of recharge and discharge areas, types and

interconnection of aquifers, and infiltration at the site

relative to total ground-water flow.  Much of this information

will be obtained during and immediately following the pre-

viously outlined geologic investigation.  During test drill-

ing, such data as water levels and head differences with in-

creasing depth would be recorded.  Test borings can be equipped

with screens and test pumped at various intervals, using other

borings as observation wells, to establish aquifer character-

istics  and interconnection between aquifers.

Historical precipitation records and estimation of surface

runoff and evapotranspiration will provide information regard-
                          "TViese-      £\
the best locations and depths of monitoring wells.   The  size

and complexity of a monitoring progra.ii will be partially based

on the calculated volume of recharge through the landfill,  and

the volume and rate of ground-water flow.  Subsequent steps

in this chapter will provide data necessary for refinement  of
the initially outlined monitoring program and elimination of

its less important features.


An accurate and complete record of existing water quality,

both ground and surface, is very useful in a monitoring program.

If contamination has already occurred, water samples from un-

contaminated areas should be collected and analyzed to estab-

lish natural water quality.  If sources of contamination other

than the landfill are present, the effects of these sources

should be determined.  Since the object of a monitoring pro-

gram is to determine change, the importance of historical

data is obvious.

If sources of contamination other than the landfill are present,

(determined in Step 2) and if existing information is insuffi-

cient to define the problem, additional  investigation will be

necessary.  Such an investigation would  include direction of

ground-water  flow in the vicinity of  the  source, rate of con-

taminant generation, nature of  the contaminants, and result-

ing degree of ground-water degradation.  The monitoring sys-

tem must then be designed to account for these "outside" con-
taminants, so that they, or their effects, are not inadver-

tently attributed to the landfill.

In addition to directly introduced contaminants,  landfill

leachate may cause secondary reactions to occur when it

reaches and blends with ground water.  For example, a mixing

of chemically reduced leachate with ground water  may lower

the oxidation potential of the leachate-enriched  ground water.

This, in turn, may reduce and dissolve iron or manganese

occurring in the aquifer materials as coatings.  Cation ex-

change reactions which release calcium and magnesium, changes

in pH, or precipitation of some leachate constituents are

other reactions which could occur and change water quality.


The leachate generation rate, which will influence the extent

of the necessary monitoring program, is determined by a water

balance study of the landfill.  Data necessary for water bal-

ance determination include:  precipitation data,  landfill

surface characteristics, vegetation type and density, land-

fill site topography, ground-water underflow rate, rate of

landfilling and pretreatment and compaction of refuse.  A dis-

cussion of water balance calculations is given in Chapter 5

of this manual.


The extent and design of a npnitoring system will be largely

determined by the pollution potential of the landfill.  Esti-

mation of the pollution potential is essentially by consolida-

tion of all data gathered in,Steps 1, 2 and 3.  Determinations

made would include:  the location, size and rate of movement

of the contaminated  plume; the aquifers affected and those

which may be  affected  in the future; the types of contaminants

present, and  the degree of attenuation of  those contaminants

by the subsurface  sediments.  Ttaie data can then be used to    —

predict  the total  pollution  damage that may be caused  by the

landfill if no action  is  taken,  or to  estimate the  influence

of various possible  abatement procedures.  Monitoring program

data SJT then  used  to establish  the  accuracy of  these  predictions

or provide  a  warning of abatement system ineffectiveness or



 The  information gathered in the previous  steps would now be

 written into a detailed report describing the investigations

 and defining the ground-water contamination problem at the

 landfill site.  Based on this report, the monitoring  system

 would be designed.  The methods  and purposes for such a moni-

 toring program are  outlined below, with detailed discussions

 of  the  various topics included  in other chapters of  this manual.


Data from the previous steps is used to rank all potential
monitoring sites in order of importance.   High priority sites

would include currently developed aquifers,  aquifers with good

development potential, and discharge areas,  such as marshland,
which could be damaged by the anticipated leachate discharges.

Monitoring sites should be selected to provide sufficiently

early warning to allow corrective action to  be taken.  Ideally,

monitoring should be sufficient to indicate  the size and type

of abatement program necessary .to correct a  problem once it

has been detected.  At the very least, the monitoring program

should insure that a health hazard does not  arise.


Following selection of the  sites to be monitored the specific

objectives of the monitoring program should be determined.

Such objectives might include:  defining the rate of leachate

plume movement, monitoring  the concentration of a specific

contaminant(s), early warning of an unexpected change in di-

rection or enlarging of the leachate plume,  or unexpected inter-

aquifer movement of the plume  to a previously unpolluted


Once the monitoring objectives have been determined, the data

requirements  to satisfy these  objectives must be  defined.

Data requirements would include:  specific chemical constitu-

ents to be included in analyses of water samples, physical

measurements to be made on dite, and the frequency of sampling

or measurement.  For example, if an objective of a monitoring

program is to  insure that leachate does not migrate into a

particular aquifer, monthly  measurements of the specific con-

ductance of water  samples from  that aquifer might be made, with

routine detailed chemical analyses run only on a semi-annual

or  annual basis.   Such a program might be  selected to provide

information  to protect the  aquifer at minimal cost.



Certain monitoring devices will be required  to  accomplish the

 specific monitoring program objectives.   For example,  at a

 specific point, a single well screened over a small section of

 an aquifer may suffice, or a cluster of several wells, screened

 over different portions of  the aquifer or in separate aquifers

 may be required.  Wells of  a particular material may be neces-

 sary to avoid interference  with leachate  sample chemistry, or

 devices other than wells might be required.  A discussion of

 monitoring  and sampling techniques is given in Chapter  5.

 A  detailed  sampling or measuring procedure should be established

 to insure uniform results.   If possible,  one person should be

responsible for sampling or overseeing the sampling to insure

uniform procedure.  This would be espeecially important for

complex procedures but less -'so for simpler procedures such as

conductance measurements.  The handling and storage of water

samples is also extremely important.  For example, if nitrogen

analyses are to be made, chilling or acidification of the

sample is required, and if metals are to be tested, acidifica-

tion with nitric acid is necessary.  A discussion of preserva-

tion of samples is given in Chapter 7.  The cost of monitoring

will vary widely depending on the sampling procedures and

analyses used, thus the program should be designed to be prop-

erly operable within the available budget.

Sufficient budget must also be reserved for proper data re-

duction, record keeping and periodic data review.  Records of

data should be in three forms:  the original data as gathered

along with explanatory notes, continuous tabular form, and

continuous graph form.  Plotting data on approximately uniform

                                       •fo \oe.
grids permits relative values and trends easily distinguishable.

Periodic review of all data by a qualified scientist followed

by a written summary, and distribution and review of the summary

                        cvfe-                    s

by all involved parties is- the proper procedure for handling

monitoring data.


Conditions under which abatement procedures, other corrective

measures, or additional monitoring steps will be taken, should

be outlined at the outset of monitoring.  Such conditions

might include constituent limits, physical parameter limits,

or trend shifts.  Possible steps which might be taken in the

event the established conditions are exceeded should be de-

termined.  An understanding should be reached as to where the

responsibility lies  for all phases of the monitoring and poten-

tial abatement programs.


Following are two scenarios of fictitious landfill investiga-

tions leading to  ground-water  monitoring programs.  The condi-

tions of the two  investigations are  somewhat different, the

first starting with  a  landfill and defining the pollution

problem, and the  second  starting with a problem and looking

for  its cause.  The  first  scenario closely  follows the preced-

ing  step outline; however,  the second is  an example of a prob-

lem  requiring  a  somewhat different  approach.   The  scenarios

are  intended as  illustrative examples and as  such  are  neces-

sarily  simplified,  i.e.,  some points included in the step  out-

line have  been omitted.   Approaches  and conclusions other  than

those presented may be equally valid,  as no attempt has  been

made to include all possibilities.   Rather,  it is  left to

the  reader to expand upon the two cases using the  factual  in-

 formation presented in the other chapters of this  manual.


 A  large county maintained landfill is found to be in viola-


 tion of the 1899 Harbors and Rivers Act allowing leachate to

 flow into and contaminate an adjacent river.  As a result of

 a  Federal lawsuit, a court order is issued ordering county

 officials to take the necessary steps to abate this condition.

 The county officials retain a ground-water consulting firm

 to investigate leachate conditions at the landfill site, de-

 termine if leachate is actually discharging to the river, and

 if so, what steps to take to abate this problem.

 The hydrogeologist assigned this project makes a visit to the

 landfill for a preliminary inspection tour with the landfill

 operator.  During this tour, he learns that the landfill re-

 ceives approximately 1,000 tons of refuse per day, about 90%

 of which is municipal; the remaining 10% is of industrial

 origin.  The refuse receives no pretreatment but after land-

 filling, it is spread into thin layers by a bulldozer, and

 compacted by a specially designed landfill compaction machine.

The layers of compacted refuse are covered daily by sandy fill

material.   Small amounts of industrial chemical waste are

accepted at the landfill but it is not separated from the

other refuse.   The rate and method of landfilling, the type

of cover material used, and local precipitation rates, indicate

that the refuse has all reached field capacity.

The landfill is 40 acres in size and is approximately 60 feet
thick with a generally  flat top surface.  Directly north of
the landfill is a hill  with*an elevation of approximately 80
feet.  South of the  landfill  is a  tidal marsh which separates
the landfill from the river.  The  distance between the land-
fill and the river  is approximately 1,000 feet.  The landfill
is not lined or covered with  impermeable materials nor does
it utilize any other leachate prevention techniques.-

The topography of  the site indicates to the hydrogeologist
that  ground-water flow is from jaorth to south with the hill
and  landfill acting as recharge areas, and the  marsh and river
as discharge areas.  The nearest supply well is located
approximately one-half mile north of the landfill and serves
 as  a supply well for an individual residence.  No other wells
 or borings SS/'be l^*i in the  landfill vicinity.
 The landfill has been  in existence  for approximately 12 years.
 There was no  special site preparation prior to landfilling;
 refuse  was simply dumped  into the edge of the marsh.  There
 is presently  little or no vegetation  apparent on most of the
 landfill surface and erosion channels on the steeper slopes
 are apparent.  Snail leachate  seeps are evident  along most
 of the  top of the  landfill.   These flow  directly into  the
 marsh  forming leachate pools which are periodically flushed
 out  into the river during periods of heavy rainfall.   A sketch

map prepared by the hydrogeologist during his field inspection
and showing important features of the landfill site is shown
on Figure  /

During his discussion with the landfill operator, the hydro-
geologist learns that the county is considering the construc-
tion of a berm, or dike, around the southern toe of the land-
fill to prevent leachate from migrating into the marsh area.
County officials feel that leachate can be trapped behind
such a berm and pumped to an evaporation pit or back to the
top of the landfill for recircuj.ation.  The hydrogeologist is
asked to evaluate the effectiveness of this scheme.

Additional observations by the hydrogeologist include the fact
that the flat, highly permeable top surface of the landfill
would allow a large percentage of precipitation to percolate
into the refuse.  In addition, surface runoff from the hilly
area to the north is free to flow onto the top surface of the
landfill and infiltrate into the refuse.  The volume of leach-
ate likely to be generated from these two recharge sources
would be considerably greater than the volume discharged by
the surface seeps.  Thus, a considerable volume of leachate
must be moving with the ground-water system beneath the land-
fill and discharging into the marsh or river.  If this is the
case,  a surface berm would do little to abate the problem.
Final  observations of the tour include the obvious stress on


vegetation in portions of the marsh directly south of the

landfill.  However, there is no visible effect of discharging

leachate on the river.

Based on his preliminary investigation, the hydrogeologist

recommends a detailed ground-water investigation to determine

if contaminated ground water is actually discharging directly

into the river and if so, the nature of the contaminants and

the rate of their discharge.  In addition, he states that in

this case, the construction of a berm may do little to abate

leachate discharge to the river if it is in fact occurring.

The results of the ground-water study, however, will suggest

what other abatement steps might be more effective.

After being advised to proceed with the ground-water investi-

gation, the hydrogeologist obtains the following:

1.  Precipitation records for the past three years from a

    weather station located twelve miles from the landfill site.

2.  A U.S. Geological Survey geologic map showing bedrock and

    overburden materials in the vicinity of the site.

3.  Information regarding the depth and construction of  the  domes-

    tic supply well north of the  landfill.

4.  A water sample from  the domestic  supply well.

5.   Water samples from the river both upstream from and ad-

    jacent to, the landfill.

6.   A sample from one of the leachate seeps.

7.   A recent aerial photograph of the site.

Analysis of the data gathered indicates that precipitation on

the landfill surface averages approximately 40 inches per

year.  The hydrogeologist then estimates that a minimum of

50% of this precipitation infiltrates the surface of the land-

fill.  Since the landfill area »is 40 acres, at least 20 million

gallons per year of leachate is  generated from this source.

The low permeability crystalline bedrock which underlies the

site probably  acts as  a  barrier  to  leachate flow.  Details re-

garding the nature of  the  surficial materials at the landfill

site are not  available.  The domestic  supply well  north of

the  landfill  was  drilled to a  depth of  100  feet and  screened

in a coarse  sand aquifer with  a high yield.  Water from this

well shows no indication of leachate contamination,  nor do any

of the water samples  taken from the river.  The seep sample,

however,  is  highly mineralized and contains contaminants

typically found in municipal refuse leachate.  A  base map of

the  landfill site is traced from the aerial photograph.

To further define the location  of contaminated ground water

 at the landfill site, an electrical resistivity survey is

  conducted.  The results of  this survey, shown on Figure  3. ,

  indicate that highly mineralized ground water is confined

  to an area of the marsh directly south of the landfill.  Some

  attenuation of contaminants in the ground water appears to be

  occurring in the direction of the river.

 While the results of the resistivity survey indicate that con-

 taminated ground water is indeed flowing from the landfill to

 the river,  additional geologic and water-quality data are
 needed to further define the problem and suggest effective

 abatement procedures.   To obtain this information,  a well

 drilling contractor is hired to install a  series of test bor-

 ings  and wells.   Subsequently,  five test borings are drilled

 on and to the  north of the landfill.   Two  casings with well-

 points are  installed in each boring.   The  locations of these

 borings,  designated A  through E for the deep wells  and A1 and

 E  for the  shallow  wells,  are shown on  Figure  3  .   As the

 drilling  rig cannot be  operated in  the  marsh area,  ten addition-

 al  test wells  are installed  in  this  area by hand.   The loca-

 tions  of  these wells, designated 1  through 10, are  also shown

 on Figure  3   .

 Construction details along with ground-water elevations,  tem-

 perature and specific conductance of ground water for  all the

 wells installed are shown on Table /  .  Based on tfcia^data, a

water-table contour map and geologic cross section  are  drawn

JL *           L              -f,^ t,     ^^e*-
                                                'r... 		a*...—	

                  .   •  >£^3
                A     »  f1-"' ifl
     —  LU U J  /[«./  ''fc*
rt  _

•f o // • — J      T

 (Figures  -7   and   *>   respectively) .   Also  shown on Figure

 is  the  ground-water head  at  each well point.  As ground water
 rv\o-jas                       ..

 fJLow* along  flowlines  from areas of  higher head to areas of    —

 lower head,  examination of the  figures shows that highly con-

 taminated ground water from  the base of the landfill is flow-

 ing downward  the  deeper sediments beneath the landfill

 and then upward and discharging directly into the river.  This

 analysis is  supported  by  the specific conductance and tempera-

 ture data.

 While some attenuation of contaminants is  occurring along the

 flow path, the attenuation is by no  means  complete.  Detailed

 chemical analyses  of water samples from all the test wells

 (not given here) confirms this.  In  addition, contaminated

 ground water from  portions of the landfill is discharging di-

 rectly into  the marsh  (Figure  5" ) and probably responsible for

 for the observed vegetation stress.   Figure  -*>'  also shows

 contaminated water discharging directly  to the river.  The di-

 lution is so great, however, that this  source of contamination

 is not detectable  in river water samples.

Possible actions that might be considered  with regard to this

problem are  as follows:

1.  Do nothing.

2.  Remove the landfill to a more hydrologically acceptable site

iU  £^4-,o

3.  Construct a shallow surface berrt\ around the toe of the


4.  Install pumping wells directly beneath the landfill to

    reverse the hydraulic gradient.

5.  Install a line of interceptor wells along the toe of the

    landfill to restrict movement of leachate away from the

    landfill toward the river.

6.  Reduce leachate generation by restricting recharge to

    the landfill.

The first possibility is unacepptable because of the severe

stress placed on the marsh by the discharging leachate.  The

second possibility is prohibitively expensive and the third

possibility would do little or nothing to abate the problem

due to the deep migration of the leachate.  The fourth and

fifth possibilities may be technically feasible, but would be

difficult to accomplish due to the low permeability of the

sediments beneath the landfill.  In addition, these two solu-

tions create the new problem of what to do with the large

volume of contaminated water pumped from the wells.  The

final possibility appears to be the best solution and  is so

recommended  to the county.

The procedures recommended to  reduce infiltration and  thus

leachate generation  are  as  follows:

1.  Close  the  landfill to duniping  as  soon as an alternate
    site can be  located.  Prepare  the new site using the

    latest technology to reduce  environmental impact.

2.  Immediately  eliminate runoff onto the landfill surface by

    means  of a cutoff trench and drain the collected uncon-

    taminated  runoff directly into the marsh for its beneficial

    flushing action.

3.  When the landfill is closed*to further dumping, regrade

    the landfill surface to eliminate its presently flat top

    surface and  create a continuous grade from the top of the

    hill to the  toe  of the  landfill at the marsh (see Figure

4.  Cover  the entire landfill surface with a compacted soil

    of low permeability.  Cover  this  compacted material with

    a layer of top soil  and plant  a high water use grass

    species such as  alfalfa.

5.  Construct a  series of swales and  channels to further in-

    crease surface runoff,  reduce  erosion and direct the

    surface runoff into  the marsh  beyond the toe of the land-

    fill (see Figure £.  ) .

In addition, the consultants recommend that the county insti-

tute a monitoring program to determine the effectiveness of the
                                                               \  '


abatement plan.  It is recommended that the monitoring data

collection begin as soon as possible to obtain antecedent in-

formation prior to making the abatement improvements on the

complete landfill.

The recommended program is as follows:

1.  Install monitoring wells of the same design as Well 2 at

    the two locations marked X on Figure   *- .  Use these,

    plus the 15 existing test wells as monitoring wells.

2.  Measure the water level in "each well monthly.

3.  Measure the specific conductance of the water in each well


4.  Take a water sample from each well yearly and conduct a

    detailed chemical analysis of each sample.

5.  If any well shows a marked change in specific conductance,

    analyze a water sample from that well immediately.

6.  Install a rain gauge on the landfill surface and record

    monthly precipitation.

7.  Reduce all data to both tabular and graph form.

8.  Review all data annually and, if necessary, adjust  the

    monitoring program as suggested by the data analyses.


 For -.:-to months, a growing  nipber  of complaints have been

 registered by residents  of a  housing development at the

 northern edge of a small city.  So far,  eight citizens from

 the development have visited., the  Board of  Health to complain,

 each with the problem that something has suddenly gone wrong

 with their drir.king water.

 The city sanitarian sends  an  inspector to  investigate the

 eight complaints.   He returns with the following report.  In

 two of  the houses,  slightly reddish water  comes from the fau-

 cets, even after running for prolonged periods.  In a third

 house,  the water is  slightly gray.   The  remaining houses are

 not experiencing discoloration, but the  water has a peculiar

 taste and  there is  a  slight odor  apparent  in the water of

 some of  the houses he  visited.

 The  inspector has collected a water  sample from each house,

 directly from the kitchen sink as  none of  the houses are using

water softeners.  The water samples  are  sent to a laboratory

 for analysis.   Meanwhile, the sanitarian marks the location

of each of  the.affected houses on  a map.   He notes that  each

house is connected to the city sewer system, but each has its

own water-supply well.  All of the houses where the problem

has occurred are in the northern half of the development, and

 within an area a quarter-mile wide.  Dozens of other houses
 are interspersed with the ones inspected and each has the  same
 type of water supply and waste disposal system.

 Only two possible causes of the water-quality problems are
 apparent.  The more likely of the two is that the 10-year  old
 sewer system has suddenly developed several large leaks and
 the raw sewage is seeping into the ground and contaminating the
 wells.   The second, and seemingly more remote, potential cause
 is  the  45-acre county landfill located more than  a mile north
 of  the  nearest affected house. : The landfill seems even more
 unlikely when the topography of the area is considered.  As
 shown  an ffiijuiu  .7  , ^torth of the development the terrain
 rises gently for several hundred yards and is then broken by
 a steep,  elongated hill, which blocks a view of the  landfill
 from the city.   Beyond the hill,  the ground slopes gently
 downward for more than half a mile to the edge of  the  landfill,
 located in  an old gravel quarry.

 Thus, for contaminated water from the landfill to  reach the
 northern  development,  the sanitarian concludes it  would have to
 travel  in an uphill direction for over a mile.  If this were
 the  case, why weren't  the houses  affected sooner,  as both they
 and  the  landfill  have  been there  for ten years.   In  addition,
why were  only a few houses in the development affected  and not
 the others?   And  what  about the four houses  located north of

the hill, between the development and the landfill,  shouldn't

they be affected if the landfill were the cause?  In an effort

to define the problem, the sanitarian sends his inspector to

obtain water samples from several additional houses  in the de-

velopment where no problem had yet been reported and also from

two of the four houses between the landfill and the development.

When the results of the water analyses came back from the lab

they did little to indicate the source of the problem.  Each

of the original eight samples, taken from houses where the

owners had complained, contained constituents well above the

recommended limits.  The constituents in highest concentra-

tions were not the same for each house, however.  Three of the

houses have water supplies with abnormally high iron content

and low pH.  In all of the samples, chloride is well above

normal for the area, but the concentrations differ from sample

to sample.  Significantly, concentrations of calcium and sodium

are abnormally high in two samples and manganese in  one.  Am-

monia is found to be above normal in five of the samples.  The

analysis of the three samples from the houses in the develop-

ment whose owners had not complained, and the two samples from

outside the development indicated the wells at these locations

are producing high quality water.

The levels of chloride and metals in several of the  samples

were too high to have originated from the sanitary sewer.  In

addition, the high-quality water in other houses in the de-

velopment would be unlikely if large leaks had developed in

the sewer line.  On the other hand, the landfill is more than

a mile away, downhill  from the development, and high-quality

water is being pumped  from wells between the landfill and the

development  so the  landfill ..still  seems an unlikely cause of

the problem.  The sanitarian  now believes that some completely

unknown  source is responsible and  decides to hire  a ground-

water expert to  determine what it  is.

A ground-water consulting  retained by  the  city, pre-

sented  with the  analyses of water  samples from the thirteen

houses  along with a map showing the location  of those houses,

and charged with locating the source of the  contaminants

apparent in eight of the samples.

The hydrogeologist assigned the task first obtains topographic

 maps and geologic maps of the area from the U.S. Geological

 Survey.  In addition, he contacts a company providing aerial

 photography services  in  a city nearby and is able to obtain

 black and white aerial  photographs of the city  and the region

 to the  north.  A visit  to  the local Health Department provides

 well records  for the  houses  in  the  affected  development.

 These  records indicate  the depth  of each well,  the geologic

  materials  penetrated during drilling,  the  static  water level,

  and  the yield of the well as estimated by the  driller.   Calls

to  three  local drilling firms produce similar records for the
wells serving the four houses between the development and the
landfill.  A visit to the landfill site and discussions with
the operator disclose the age of the landfill, the methods of
landfilling used and the surface conditions and drainage char-
acteristics of the landfill.'

With these data available, the hydrogeologist is able to es-
tablish the following:

 1.   The houses in the  development and the four houses north
     of the development are resting on a layer of glacial till
     between 10 and 30  feet thick.

 2.   Beneath this till  layer is  an extensive sand and gravel
     aquifer which is probably about 50  to 100 feet thick.
     Underlying this  aquifer is  crystalline bedrock.

 3.   The general  direction of  ground-water flow in the area
     is  from the  mountainous area ten miles north of  the city.

4.   The gradient of  the water table  in  the vicinity  of the
     development  is low, but the permeability  of the  aquifer
     is  quite high.   The rate  of ground-water  flow in the area
     is  about 2 feet  per day.

5.   The wells belonging to  houses  in the  development,  with
     the exception of the  eight  contaminated wells, are screened

     near the top of the sand and gravel aquifer in an  inter-

     val of about 50 to 60 feet below land surface.

 6.   With corrections for differences in elevation, the four

     wells belonging to the houses north of the  development

     are screened at approximately the same depth in the aquifer

     as the majority of the development houses.

 7.   The eight contaminated wells in the development are

     screened substantially deeper than the other development

     wells.  In four of these, a 10-foot thick clay lens was

     penetrated at the normal screening depth of 40 to  60 feet,

     and the wells were drilled an additional 20 feet into the

     sand and gravel beneath the clay.  The remaining four

     wells were drilled at a later date by a different  drill-

     ing firm and were inexplicably deeper.

 8.   The landfill, located 6,000 feet upgradient of the devel-

     ment, is situated in an abandoned gravel pit, which is

     probably connected directly to the aquifer serving the


 9.   The landfill is roughly circular, covering an area of

     about 45 acres, and is about 1,600 feet in diameter.

10.   The contaminants reported in high concentrations in the

     eight wells in the development are characteristic of

     typical municipal landfill  leachate.

11.  Mo significantly large source of contamination other

     than the landfill and the sewer system is located in
     the immediate vicinity of the development or upgradient

     of the development as far as the mountains 10 miles


12.  The landfill is 10 years old, has a broad, flat upper sur-

     face, and the deposited refuse is covered daily with sand

     taken from an unfilled portion of the old gravel bank.

13.  Rainfall in the area 40 inches per year.

Based on these findings, the hydrogeologist concludes that it

is indeed possible, in fact probable, that the landfill is the

source of the contamination found in the eight wells.  He rules

out the sewer as the source of contamination since it is the

deeper wells, rather than the shallow ones, which had become


Using the available geologic and hydrologic data, a cross

section of the area, including the landfill and the development,

is drawn illustrating how only the deeper wells would become

contaminated (see Figure "7 )•  Since the landfill is probably

resting directly on top of the aquifer, leachate generated in

the landfill would flow into and move with the natural ground

water.  From other landfill investigations, however, it is known

that leachate can flow as a distinct plume with relatively


little dispersement in the ground-water system.  Furthermore,

this plume may tend to sink toward the bottom of the  aquifer

as it noves.  Thus, the plurre might be just  thick enough to be

picked up by the deeper wells but still could flow  underneath

the shallower ones, as illustrated in Figure 7 .   The second

part of the problem, the 10-year delay for the  contamination to
appear, is answered by the estimated flow rate  of the ground

water.  Assuming the leachate began to move into the aquifer

during the first year of landfilling, it took approximately

3,000 days to reach the vicinity of the first well.  Because

the distance from the landfill to the well is  6,000 feet, ground-

water velocity would have to be 2 feet per day, which is what

it is estimated to be.  An explanation for how contamination

traveled the 400 feet from the first well affected to the last

well affected in only 60 days  (rather than 200) is provided by

the change in velocity of the ground water as it enters the cone

of influence created by the large number of pumping wells in

the development area.

The width of the affected  area,  one-quarter mile,  is  explained

by the width of the landfill  itself  (see Figure ff  ).   Since it

is possible for a  leachate  plume to migrate without  substantial

dispersion  and  remain  at  approximately its  original  width for

substantial distances,  and thus,  should be  at  least  1,600 feet

wide  (probably  somewhat wider)  as it  reaches the development.

I    I

Along with the data and findings, the ground-water consultants

include the following recommendations in their report to the


1.  Immediately advise the owners of the contaminated wells to

    obtain their drinking water from other sources.

2.  Collect water samples from all the unsampled wells in the

    subdivision and analyze for chloride, calcium, and iron.  If

    any abnormal concentrations are found, advise the owners of

    those wells not to drink the water.

3.  Immediately institute an investigation to positively es-

    tablish the landfill as the source of the problem, and define

    the actual extent and rate of movement of the contaminants.

    In addition, detailed water analyses should be performed to

    determine what potential health hazards exist.

4.  When the problem has been defined, establish what abatement

    procedures might be effective.  Evaluate the various possible

    procedures and define which will be the most effective.

The City Department of Health decided to carry out the first two

recommendations themselves.  The consulting firm is contracted to

undertake the work necessary to satisfy the third and fourth



The first phase of the  consultant's  investigation,  to es-

tablish the  landfill  as the actual cause  of  the problem and

to define the nature  and extent of the  leachate plume is

undertaken as a series  of tasks.

Task 1 - Assemble  and analyze all available  background data

          (already  done  during preliminary investigations).

Task 2 - Conduct a field inspection  of  landfill site  (already

         done during  preliminary  investigation).

Task 3 - Conduct a resistivity survey to  attempt  to define

         the depth and  lateral extent of  the leachate plume.

Task 4 - Drill a total  of 6 wells down to bedrock to verify

         the results  of the resistivity survey and obtain

         geologic  and water samples.  Conduct pumping tests

         to  determine actual hydrologic characteristics  of

         the aquifer.

Task 5 - Construct a  water-balance  model  of the landfill to
IB««^__«»«^^^_    ^

         accurately determine the contributions of precipita-


         tion  and  underflow to the  volume leachate generation.

         This  task would be accomplished entirely with  exist-

          ing data.

The results of the Phase 1 investigation indicate that the

preliminary analysis of the situation was essentially correct.
Furthermore, the leachate plume is found to contain hazardous

constituents originating from industrial wastes which are

traditionally accepted at the landfill.  The .volume of leachate

being generated by the landfill is calculated at approximately

80,000 gallons per day from precipitation with no significant

contribution from underflow.

Based on these results, two alternative abatement programs are

presented to the city.  The first half of both programs is the

same, eliminate the source of the pollution.  The second half

of the program deals with what to do about the leachate that

is already in the ground.  Monitoring recommendations are in-

cluded with both programs.  ABATEMENT PROGRAM 1

It is recommended that placement of refuse of the existing county

landfill be stopped as soon as an alternate disposal site can

be located and prepared.  The selection of a new site should be

based on geologic and hydrologic considerations so that a new

ground-water contamination problem is not created.  Site prepa-

ration and landfilling methods should be based on the latest

technology to minimize the possibility of leachate contamina-

tion of ground or surface water.

Preparation should begin  at once to regrade the existing land-

fill to eliminate the  flat top surface and provide adequately

steep side slopes to promote runoff of precipitation.  The

upper surface of the landfill should be covered with a minimum

of two feet of compacted  soil with a low permeability to mini-

mize infiltration.  This  upper layer should then be covered

with a one-foot layer  of  top soil and seeded.  A dense vegeta-

tion cover should be maintained on the landfill surface to

maximize evapotranspiration.

It has been determined by aquifer tests that the leachate pres-

ently in the ground-water system can be removed by a series of

high-capacity pumping  wells.  Three 10-inch diameter wells would

be installed 400 feet  apart across the plume (shown in Figure   )

and 500 feet north of  the development.  The wells would be

drilled to rock and be screened from 80 feet below land surface

to rock, to include the entire thickness of the plume in the

screened zone.  The wells would be pumped continuously at a

rate of 2,000 gpm  (gallons per minute).  This will establish a

hydraulic barrier which will block leachate flowing south from

the landfill site toward  the development.  In addition, leach-

ate south of the barrier  wells will be drawn back toward the

wells by the induced reversal in gradient.  When the polluted

water has been removed from the aquifer beneath the development,

the pumping rate of the barrier wells can be reduced to 700 gpm

and the eight deep development: wells can be returned to use,

but with continual monitoring of their quality for a period

of tirr.e.                    •;

While this program will effectively eliminate the present prob-

lem, a new problem of what to do with the contaminated water

pumped from the barrier wells will arise.  Since the capacity

of the treatment plant is insufficient to handle this addition-

al volume, the water would have to be piped away and discharged

untreated either back at the landfill site or into the river at

the south end of the city.  There are many serious problems with

these possibilities, however, and subject to further investiga-

tion, both may prove unacceptable.  The only remaining alter-

native then would be the construction of additional treatment

facilities.  ABATEMENT PROGRAM 2

Discontinue landfilling and complete the existing landfill as

described in Program 1.  Abandon use of the eight contaminated

wells for water supply but keep them intact for use as observa-

tion wells.  Drill eight new wells to a depth of 50 feet below

land surface.  These replacement wells would then be screened

above the contaminated zone, at approximately the same depth

as the other wells in the development.

 Allow  the  contaminated plume  co  flow  along its natural course
 toward the river.   Since  there are no city supply wells or
 other private wells in its path, no additional effects will
 be apparent until the  plume reaches the river.  The additional
 three miles the plume  must travel might be sufficient to attenu-
 ate most of the contaminants.  The progress of the plume should
 be monitored by a series of observation wells placed along its
 route.   These monitoring wells will determine if attenuation
 is actually occurring at a significant rate and if the plume
 is altering its course.  If at some time in the future it is
 determined that the contaminants within the plume are not being
 sufficiently attenuated and will be deleterious to the river,
 a  series  of barrier wells should be installed to intercept the
 plume prior to its reaching the river.

 The city  should  consider the  possibility of connecting the
 northern  development to the city  water supply,   while  this does
 not appear  to  be immediately  necessary, continued close monitor-
 ing of  the  location  of  the plume  in the vicinity  of  the develop-
ment may  detect  an enlargement of the  plume and  all  the wells
would have  to be abandoned.

                     A-l FUNDAMENTALS OF  LEACHATE

 In their publication,  Summary  Report;  Gas  and Leachate from Land Disposal

 of Municipal Solid Waste.  U.S.E.P.A.,  Cincinnati, Ohio, 1974,  the U.S.E.P.A.

 presents an excellent  comprehensive  summary on leachate, its production and

 characteristics.  Much of  this material  has been reproduced and included

 in this  appendix  for the convenience of  the user of the manual.  Herein-

 after, the  above-referenced report will  be  called the leachate summary


 Two other reports on leachate which  are  pertinent to assessing potential

 leachate contamination at  land disposal  sites are:

          .  Use of the  water balance  method  for predicting leachate

            generation  from solid waste disposal sites, Office of

            Solid Waste Management Program,  U.S.E.P.A., October 1975,


         . An environmental assessment of potential gas and leachate

            problems at land disposal sites.  Office of Solid Waste

           Management  Programs, U.S.E.P.A.,  1973,  (SW-110).

These reports will also be referenced in this section and will be referred

to as the water balance report and environmental assessment report respectively,

It is intended that this appendix provide the user of this manual with suf-

ficient information to assist in performing an assessment of potential leachate

contamination at land disposal sites.  This, in turn,  is used to determine

the need, type and intensity of monitoring that should be assigned to a

particular land disposal site.


In their environmental assessment report, EPA puts leachate production into

perspective.  It states:

         "It becomes quite evident that the main parameter affecting
         leachate quality and quantity is purely and simply the
         quantity of water flow through the solid wastes.  Generally,
         the more water that flows through the solid waste, the more
         pollutants will be leached out.  Therefore, the proper sani-
         tary landfill design and operational approach is to eliminate
         or minimize percolation through the solid waste.  With the
         smaller amounts of percolation, the pollutants tend to be more
         concentrated, but the rate at which they are transmitted to
         the surrounding environment is not so apt to exceed the capabil-
         ity of the natural surroundings to accept and attenuate most
         of them to some degree."

Therefore, one can see that the volume of leachate generation is influential

in both the extent of a leachate contamination problem and the relative

strength of the leachate and its concentration in the ground water being


Estimating leachate generation can be useful in designing a monitoring

program, and interpreting  the data collected in the following ways:

         . Predicting the  time of first appearance of leachate.

         . Predicting the  potential quantity of pollutants generated

           at a land disposal site.

         . Help explain fluctuations in monitoring well data that
           may occur, and

         . Relate operational characteristics and site conditions

           to potential leachate  generation.

 In the  leachate summary report, and  the water balance  report, EPA

 applies the water balance method as  a useful tool in estimating leachate

 generation at a land disposal site.

 In addition, the leachate summary report provides an excellent summary

 of  leachate characteristics as has been observed by many researchers in

 the field.  Data are presented on the quality of pure leachate as well as

 samples of leachate-enriched ground water.  Examples are also given

 depicting the relationship of leachate concentrations  to quantity produced

 and season of the year.  A comprehensive list of references on leachate is

 also presented.

 For the convenience of the manual user, sections have  been reproduced from

 the leachate summary report and the water balance report and included as

part of this appendix.

The following section has been reproduced from:



Cincinnati, Ohio, 1974.

                               SECTION VI

                           LEACHATE PRODUCTION
 The various physical, chemical, and biological processes that occur
 when  solid wastes are disposed on land produce compounds that are sus-
 ceptible  to solution or suspension in water percolating through the
 disposed  solid waste.  This percolating water containing solids de-
 rived from the solid waste is called leachate.  The volume of leachate
 produced  at any particular site is dependent on many factors, but
 generally, is determined by the quantities of surface water infiltra-
 tion  and/or interceotion of groundwatsr.  Compos iti on of Icachate is
 highly dependent on the comoosition of solid waste, its aqe,-and the
 environment in which it is located.  Environmental conditions, such
 as temperature, moisture regimen, and the availability of oxygen are
 significant factors in determining the exact chemical constituents
 contained within leachate.


,The sanitary landfill site is a part of the classical hydrclogic
 cycle.  The governing criteria for determining leachate volume are
 those describing the phenomena occurring at the cover material sur-
 face.  A  water balance can be written:
where  WR = input water from precipitation

      w"sR = input water from surrounding surface runoff

      WGW = 1nPut water f™m groundwater

      WIR = input water from irrigation

        I = Infiltration

        R = Surface Runoff

        E = Evapotranspiration

 Infiltration can be defined:

                    I = ASs + 6Sp + L + WD	  [2]

 where  AS  = change in moisture storage in soil
          ^                                                        •
        ASD = change in moisture storage in solid waste
          L = leachate

         WD = v/ater contributed by solid waste decomposition

 Proper design and operation can eliminate input water from surrounding
 surface runoff, groundwater and irrigation.  Some control can  be
 exerted over infiltration, evaporation, surface runoff, and moisture
 storage capacity of soils and solid waste.  The volume of vater pro-
 duced during solid waste decomposition is generally considered negli-

 Use :of the v/ater balance has been proposed by Remspn, et al.
 Fenn and Hanley,2 Salvato, et al.3 and California.1* The volume of
, leachate, tine of initial occurrence, and subsequent flow rate and
'allowable volume of irrigation v/ater can all be determined by  appro-
 priate use of the v/ater balance.  The Rsuson work, supported in part
 by U.S. EPA Research Grant R301947, provided a useful computerized
 moisture routing technique.  Salvato, et al., and the California  sum-
 mary discuss the various factors that influence rrnoff and infiltra-
 tion and provide guidance for determining approximate values.  Fenn
 and Hanley applied the water balance to hypothetical landfills in
 Cincinnati, Orlando, and Los Angeles.

 Determination of runoff from landfill surfaces by the rational runoff
 formula was proposed by Salvato, et al.  They provided tables  for a
 rainfall of 25.4 mm/hour (1 inch/hour) intensity and 6-hour  duration.
 The empirical runoff coefficients (C) used v/ere from Frevert,
 et al.5  and are provided in Table 5 along with calculated quantities
 of runoff for a 25.4 mm (1-inch) rainfall.  The influence of slope,
 surface condition, and soil type on the quantity of runoff and the
 potential for leachate production is clearly demonstrated  in Table 5.
 As great as 55 percent change in runoff and infiltration is  attributed
 to slope.  As great as 173  percent change  in runoff and  infiltration
 is attributed to soil type.  As great as 71.5 percent change in  run-
 off and infiltration is attributed to surface condition  (vegetation,
 bulk density).  A silt or clay  loam, in a  pasture land  area  at a
 5 to 10 percent slope is generally recommended  for encouraging run-
 off, limiting erosion, and  avoiding soil shrinkage oroblcns.  As
 such, a coefficient of 0.36 would apply and one mignt expect from a
 storm of 25.4 ir.m/hr (1 inch/hr) intensity  and 1 hour duration, approxi-

mately 9.06 m3/ha (9,690 gal/acre)  runoff and  16.3 n.3/ha  (17,400 gal/
acre) potential infiltration.   Of course a large  amount of  this in-
filtration is lost by evaporation and transpiration.   The remainder
qoes first to meeting moisture retention (storage) capacity of  the
soil and solid waste and then to leachate in accordance with
Equation 2.                                                                         ;
Determination of the runoff from storms by the rational runoff  formula              !
is largely dependent on the accuracy of the coefficient,  C, chosen                   j
for the specific site.  Mot specifically considered  in the  rational
runoff formula are:  the previous moisture conditions of  the site and               i
the limitation imposed by the hydraulic conductivity of the soil.                    ,
Infiltration rates generally cannot exceed the hydraulic  conductivity
 permeability) of the soil.  The hydraulic conductivity of  soils  has                !
been conveniently tabulated.*  Table 6 provides estimates of maximum                ;
hourly infiltration for these soils assur.-.ino Q = CiA is aoolicaDle,
the soils  are  saturated and uniform, and  sufficient water is avail-
able.  Comoarison of Tables 5 and 6 Indicates the necessity for care-
ful determination of the hydraulic conductivity of proposed cover
soils  (differences as great as 1Q3 in  the same soil group)  and inter-
pretation  of the results of the  rational  runoff formula.

 Infiltration is  dependent on  the frequency, duration, and  intensity
of rainfall.   These  precipitation characteristics are significant
 in determining the  previous moisture conditions of the soil and hence
 the amount of water  required  to  reach  saturation when the  hydraulic
 conductivity of the  soil will  control  infiltration rates.   The Bureau
 of Reclamation7 has  related  rainfall  intensity to infiltration, and
 has accounted for  differences due  to vegetation, soil type, precipi-
 tation,  end evaporation.   Appropriate  relationships  are  depicted in
 Figure 2 and Table 7.

 The importance of vegetation in promoting infiltration is  clearly
 shown in Table 5.   The density and type of vegetation are  also im-
 portant in determining evaporation and transpiration.  Consumptive
 use of water. Table 8> is  determiner; largely  by  the vegetative-soil
 system, but ranges have been compiled.

 Moisture retention by soil is dependent on soil  type and previous
 wetting.  Soil will retain a characteristic amount of water against
 the pressures exerted by gravity and plant roots.   These are referred
 to as field capacity and wilting point respectively.  They are com-
 monly expressed as a percent of volume or as a depth per unit depth
 of soil.  Examples are provided in Table 9.  The difference in water
 retained  between the wilting point and the field is that
 amount available for evapotranspiration  and storage.

                                               Table 5.  RUNOFF AND INFILTRATION FOR A 2.5 cm RAINFALL*
Surface condition
Pasture or meadow
(cover crop)
(no vegetatto)
not compacted
BAftcr Salvatn. J. A.

. Vllklt.
Rational runoff coefficient6-0
N. 6. aid NN4
Clay or


. 1. E. "Unitary Landfill
Ruifoff In mVh«d>e

Clay or

Prevention and

Infiltration In mVhae
' loan
< 230
, (24.500)
• 199
(21 .200)

! (19.100)
- 153
. (13.100)
t^^M»*l UDi^sT
•IMinM 1 Krlr i
Clay or

43 (10). 2084

bFrevert. Schwab, {dsrfnster and Barnes.  Soil and Water Conservation Engineering. Wiley, pp.  439 (1963).
cVcn TeChOM. "Handbook of Applied Hydrology.-   (1964).'
dO • CIA.
•Nuobon In parenthesis refer to gallons/acne.

                                            RAINFALL, nun/hr.
               Note:  See Table 7 for application
                      of curve number.             /
         0.5  -
                                              RAINFALL, in/hr.


Soil description
Well-graded gravels or gravel-sand
mixtures, little of no fines

Poorly graded gravels or gravel-sand
mixtures, little or no fines

Silty gravels, gravel-sand-siIt
Clayey gravels, gravel-sand-clay
Well-graded sands or gravelly sands
little of no fines

Poorly graded sands or gravelly sands,
little or no fines

Silty sands, sand-silt mixtures
Clayey sands, sand-clay mixtures
Inorganic silts and very fine sands
rock flour, silty or clayey fine sands
or clayey silts with slight plasticity
                                            ID'3 to 10~6
                                               6       8
                                            10-  to 10-
                                               3       6
                                            10-  to 10"
                                               6       e
                                            10-  to 10-
                                            10'3 to 10"
>3.6xlO  .

>3.6xl03 5
(>3.85x10 )

3.6x10 ,to
3.6x10- \
(3.85x10  to
3.6x10"3 to
3.6x10" i
(3.85x10, to
3.85x10- )
>3.6xlO  n
(>.3.85x10 )

>3.6xl02 .
3.6x10 ,to
(3.85x10  to
3.85x10 )

3.6xlO~3 to
3.6x10- .
(3.85x10, to
3.85x10" )

3.6x10 ,to
3.6x10- ,,
(3.85x10  to

            Soil description3
	m  /ha
 Organic silts and organic silt-
 clays of low plasticity
 Inorganic silts, micaceous or
 diatomaceous fire sandy or silty
 soils, elastic silts
 Inorganic clays of high plasticity,
 fat clays
 Organic clays of medium to
.high plasticity, organic silts
 Inorganic clays of low to medium plas-
 ticity, gravelly clays, sandy  clays,
 silty clays, lean clays
10'* to 10-
  -  to 10
10-6 to 10-B

ID"6 to 10-8
TO'6 to 10-8
 3.6x10  .to
 (3.85x10* to

   85x1 0
3.6x10-*  to
(3.85x10   to
3.85x10-  )

3.6xlO-J  to
(3;85xTO:  to
3.85x1 O-1)

3.6xlO'l  to
3.6x10- ,
(3.85xicj  to
3.85x10-  )
 aSoil  description  according to USCS.

 lumbers  in  parenthesis are gal/acre.

Soil type
'Sandy loam
Sandy loam
Clayey loam
Clayey loam


, 2 •


M va


aSanitary Landfill Studies:  Aooendlx A — Sumrary of Selected Previous
 Investigations.  California Department of Water Resources.   Sacramento.
 1969.  115 p.

bM Increases with degree of soil saturation.

cCurve number refers to Figure 2.
= e
            + 1)
                   for noni-rr1gated areas.
 M = e ( 60 + 1) ^ A  f0r irrigated area such as parks, where A is
                      allowance for irrigation = 0.11.

     where:  e = evaporation = (0.9 - e6Q     )
                                   e annual
  where:  (e60) = pan evaporation for preceding 60 days.

          (e annual) = man annual pan evaporation.

          °60 s weighted preceding 60-day precipitation as:

          d60 -
                            p(5-9) + p(10-14) + p(15-30) + p(31-60)
                                ~      ~~      "6T67         *"


   Vegetation                                    mm/unit area
Coniferous trees                                   102-229
Deciduous trees                                    177-254
Potatoes                                           177-280
Rye                                                457-up
Wheat                                              509-560
Grapes                                             152-up
Corn                                               509-191
Oats                                               711-1020
Meadow grass                                       560-1525
Lucern grass                                       660-1400

aAdapted from Urquhart, L. C., Civil Handbook.
 New York, McGraw-Hill,  p. 9077January, U-50.

             Table  9.  MOISTURE CRITERIA OF  SOILS

Fine sand
Sandy loam
Silty loam
Clay loam
Clay loam

.12.5 '


(2) .
Sanitary Landfill Studies, Appendix A - Suircnary of Selected Previous
Investigations.California Department of Water Resources, Sacramento,
Thornthwaite, C. W. and Mather, >J. R., "Instructions and Tables for
Computing Potential Evapotranspiration and the Water Balance".
Publications in Climatology, X(3), Drexel Institute of Technology,
Laboratory of Climatology.  1957.

                    Table 10.  MOISTURE RETENTION OF SOLID WASTE9
Initial Moisture
X Wet Weight

m/m in/ft.
Solid Haste
Density ,
kg/mj lb/yd:
392 661 '
430 727
417 705
592 1QOO
337 570
314 530

5 "

 Notes:   a   adapted  from A. A. Fungaroli and R. L. Steiner "Investigation of Sanitary Landfill
             Behavior" Research Grant R800777 October 1973.

         b   unit wet density

         c   not  corrected for evaporation and transpiration losses.

         d   includes H_0 retained in soil cover.

         e   includes H.O retained in sub-drain.-

         1.   "Project Plan.  Test Cell 2. Boons County neld Site." Solid anc! Hazardous Waste
              Research Laboratory, U.S. EPA, Cincinnati Jan. 1973 (manuscript).

•   .      2.   Rovers, F. A. and Farquhar, G. J. "Infiltration and Landfill Behavior" in
              Proceedings of the American Society of Civil Engineers.  99 (EE5), pp 671 - 690.
              October 1973.

         3.   "Pollution of Water by Tipped Refuse" Ministry of Housing and Local Government,
              Her Majesty's Stationery Office, London, 1961.

         4.   Merz, R. C., Final Report on the Investigation of Leaching of a Sanitary Landfill.
              State  Hater Pollution Control Board.  Publication 10.' Sacramento, California
              1954.  91 p.

         5.   Qasim,  S. R. and J. C. Burchinal "Leaching from Simulated Landfills," Journal of
              the Hater Pollution Control Federation 42, pp 371-379, March 1970.

Moisture retention in solid waste is similar in concept to that of
soil except no data is available on the v/ilting point.   It is gen-
erally assumed that water is lost fropi the solid waste  in significant
amounts only through percolation.  Table 10 and Figure  3 provide a
suirjnary of data on the field capacity of solid waste.   Deeds-position
of the solid waste, particle size, density, and initial moisture
content account for the wide range in reported values.

The moisture retention capacity of solid waste has been proposed for
exploitation as a receptor of liquid wastes and sludges.  Examples
are municipal water and wastewater treatment plant sludges, commer-
cial wastes such as vegetable market e.nd restaurant wastes, and in-
dustrial liquid and sludge wastes not permitted to be discharged to
streams.  Such a contribution of water to the solid waste in the
sanitary landfill does not necessarily create a leachate problem or
significantly affect the total volume of leachate produced.  The fol-
lowing hypothetical example will indicate the quantities involved.

A typical sanitary landfill, 592 kg/m3 (1,000^/cu yd)  of municipal
solid v/aste, placed 3 meters deep (9 feet) will hold approximately
760 ram (30 inches) of H20/unit surface area (18.7 gallons of hhO/sq ft)
before steady state leaching occurs.  If no sludge or high r.oisture
bearing solid v/aste is added to this waste, then 3 years will likely  .
elapse before steady state leaching is established (based on assump-
tion of 25* rr.ri (10 inches/sq ft) annual net infiltration).  If 508 rai
(20 inches) of excess moisture (12.4 gal/ft2) is added to the solid
waste during deposition, then steady state leaching will likely occur
1 year later.  Total leachate volurr.e produced in the first 10 years
with no intentional moisture addition during deposition is aoproxi-
mately 2,540 mm (100 inches), (62.2 callons/sq ft); if 503 .V.TI (20
Inches) of moisture is added during deposition, then leachete volurr.e
after 10 years is approximately 3,050 ran (120 inches),  (74.5
gallons/sq ft).

It is obvious from the example that'the occurrence of leachate will
be accelerated if water is added to the landfill.  It is not as ob-
vious, nor is it as easy to evaluate the impact on leachate and gas
characteristics.  Additions of water and the compounds dissolved in
it may accelerate decomposition as well as inhibit it;  it may create,
magnify, or reduce the impact of leechate on the environment; opera-
tional problems may be solved as well as created.

The seasonal dependence of evaporation, transpiration,  and infiltra-
tion and the dependence of all these factors on the distribution of
rainfall and available moisture throughout the year create a complex
problem that has not been rigorously solved.  Remson presented a
moisture routing procedure easily adaptable to electronic ccmputa-

           a.  Adapted from A. A. Fungaroll and R.  L. Stelner,
               "Investigation of Sanitary Landfill  Behavior"
               Research Grant R800777, October 1973.
           b.  Moisture retention based on data from Initially
               saturated samples.
                                                         \ ••
3   6


                       ,Q   O

                       ?  o
                                                  ee   w°e    °°
                                               or3 IP Q





                                                                                     L'nground  ?

                                                                             600    700   COO  900
                                 Unit Dry  Dens'lty (pounds/cu yd)
                     Figure 3.  Moisture retention capacity of solid waste1' *

 tion.  Fungaroli8 developed a national  evaluation of potential infil-
 tration, Figure 4, based on annual  averages  for evapotranspiration
 and rainfall and no surface runoff.   Inclusion of surface runoff re-
 quires Identification of site-specific  characteristics; evaluation
 of leachate volume is best left to  analysis  of specific sites, rather.
 than regional generalizations.  Fenn and Hanley applied the water
 balance, including provision for surface runoff and evapotranspiration
 for Cincinnati, Orlando, and Los Angeles.

 Control measures, such as diversion of  upland drainage, sloping of
 cover material, use of relatively impermeable soils for cover mate-
 rial, rapid attainment of final elevations,  planting cf high transpir-
 ing vegetation, use of impermeable  membranes overlying the final lift
 of solid waste, maintenance of final grades, and use of subsurface
 drains and ditches to control groundwater, are available to the de-
 sign engineer and operator.  Use of impermeable membranes requires
 vents to nonage landfill cases and  drains tc manege tha intercepted
 infiltrating water.  There is a general paucity cf quantitative in-
 formation on the use of these controls.

 Hughes, et al.9 calculated from piezometer calculations that 40 to 50
 percent of the annual precipitation of Illinois of 838 ram  (33  inches)
'will infiltrate the surface of landfills to produce leachates.  In
 the dry California climate ir.ore than two-thirds of the simulated
 rainfall applied to a solid waste cell  was evaporated.10  The  only
 landfills where the amount of runoff is actually  measured are  the
 test fills in Sonoma County, California.11

 The results of the test cells in Figure 5 show that with a  low amount
 of rainfall approximately 40 percent leaves the landfill as  overland
 runoff.  At higher intensities, a constant amount of  suprox.inately
 14 mm  (0.55  inch) is retained at the surface of the  fill while pre-
 cipitation  in excess of this aRicunt appears as runoff water.
 Schoenberger and  Fungaroli12 found  that during the winter  period  two
 landfills  in Pennsylvania produced  leachate at a rate of 0.29 cm/day
 and  0.23 cm/day which amount  is equal  to  the net precipitation (rain-
 fall-evaporation) in that period.   Lower  percentage infiltration  are
 experienced  in Europe.  Only one European study measured a leachate
 volume equal to 44 percent  of  the yearly  precipitation.13   More
 typical values lie around  10  to 26  percent  (Reuss, 1971) or 10 per-
 cent11*  (Pierau,  1968) corresponding with  an amount of leachate of
 0.03 to 0.10 1/sec/ha or 0.3  to 0.9 mm/day.  Klotter and Hantge15
 (1969)  measured  a flo;/  rate of O.C6 1/sec/ha for a 9 ha. landfill,
 while  Knock and  Stegnan16  (1971) calculated  a volume of 0.08 1/sec/ha.
 The  considerable  spread  in  the relative amount of leechate generated
 from landfills may  indicate that by properly manipulating the nature
 and  the slope  of the surface cover, the amount of Teachate can be re-
 duced  or enlarged as desired.

 // //• '• ' *F~«.Vv»v- £&~*f -:N
 (/£    ^A;v::^v>.v- -:•
 1/rB'A^ ^--^  :

^tV  ^X^!^V):v^

 I,;-' •';. .  <^ Jk  v ;.,'\ .5-.>..
Relation between amount of dolly precipitation
and runoff from the pilot field scale sanitary
landfills cell  A and C and cell Q, Sonona County
during the winter of 1972 and spring of 1973.
The cells have  a 2 feet thick clay cover placed
under a 2 X  slope.
                                   first rain
                                   of the season
                            observed quantity
                            of  runoff
                                                           RUNOFF, (in.

                                   Figure5  .   OBSERVED RUNOFF FOR PRECIPITATION EVENTS.

The critical  area of limited  information appears  to be determination
of surface runoff/infiltration under  surface conditions prevalent at
sanitary landfill sites.   Such factors  as  slope,  erosion, vegetation,
soil density, and soil  type are  factors that need to be studied fur-
ther,  l.'ork presently being conducted under U.S.  EPA Research Grant
R802412 is evaluating the net infiltration through simulated sanitary
landfill cover materials  with three soil types,  three soil densities,
and three types of vegetation.   This  work  needs  to be expanded and  the
influence of slope determined.   Hydraulic  properties of cover mate-
rial and solid waste need to  be  determined. An  extensive review of
existing water accounting and routing methods, culminating in a
method for leachate volume prediction and  its  verification is needed.


The compositions of leachates reported  1n  the  literature are quite
diverse.  R?ngps of specific  chenical characteristics  of those  studies
listed in Table  11 are typical.  'The  breadth of reported data are  also
typical for  individual studies17 over a long period  of time.  The  many
factors that contribute to the spread of data  are tir.a since deposi-
tion of the  solid waste; the moisture regiman, such  as total volune,
distribution,  intensity, and duration;  solid waste characteristics;
temperature; and sapling and analytical  methods.  Other factors
such as landfill geometry end interaction of leachate with its  envi-
ronment prior  to sar.-.ple collection also contribute to the  spread of
data.  Nost  of these factors arc rarely defined  in the literature,
making  interpretation and coir.parison with other  studies difficult,
if not  rather  arbitrary.

Some cements  regarding  the  studies  tabulated-are warranted."  Cursory
examination  of Table 11  indicates leachate is generally high in or-
ganic  content  (BOD5  =10,000, COD =15;COO,  TOC =5,700) and total solids
 (>1  percent),  is slightly  acid  (pH 5.0*1.0) and  contains low heavy
metals  (<1.0 ppm)  except for iron which is commonly present in levels
of 1,000  ppm.

The data  presented from  the  Solid and  Hazardous  Waste Research Labo-
 ratory were  obtained at  the  Boone County  Field  Site Test Cell 1 which
 contains  395 tons of municipal  solid waste compared to 592 kg/m3
 (1,000 lb/yd3.  Test Cell  1  was constructed in  1971 in accordance
 with best available sanitary landfill  technology at that time.

 The data  reported from the University  of  Illinois were obtained under
 U.S. EPA Research Contract 63-02-0162. The leachate vas generated
 from a laboratory lysirr.eter, 1.22 m  diameter  (4 feet), containing
 1,520 kg (3,353 pounds)  of shredded  solid waste, 33 mm  (1.5 inch)
 grate opening, compacted to  330 kg/m3  (556.9  lb/yd3).  Water was

The critical area of limited information appears to be determination
If surface runoTf/Infiltration under surface conditions Prevalent at
sanitary landfill sites.  Such factors as slope, erosion,  vegetation,
soi  dens ty  and soil type are factors that need to be studied  fur-
ther  T/ork presently being conducted under U.S. EPA Research  Grant
TO02412 is cwlwtlng the net infiltration through simulated  sanitary
landf 11 cover Materials with three soil types, three soil densities,
and three types of vegetation.  This work needs to be expanded and  the
Influence of slope determined.  Hydraulic properties of cover ma«-
rla  and solid waste need to be detennined.  An extensive review of
existing water accounting and routing methods, culninating in a
method  for  leachate volume  prediction and its verification is needed.
 The compositions of leachates reported in the  1  terature are *"*
 diverse'.  Ranaes of specific chemical  characteristics  of tho>e studies
 listed  n Table 11 are typical.  The breadth of  reported aata are also
 typical ?or individual studies^' over a long period of time   The many
 factors that contribute to the spread of data  are time since deposi-
. tion of the solid waste; the moisture regirr.en, such as total yo ume,
 distribution, intensity, and duration; solid waste characteristics,
 temperature; and sampling and analytical methods.  Other £^°r*   .
 such as landfill geometry and interaction of leachate witn i^s envi-
 ronment pr?or to ILple collection also contribute to tta  spreaci  of
 data.  Most of  these  factors are rarely denned in the literu-urc.
 making interpretation and comparison with other studies difficult,
 if not rather arbitrary.

 Some consents regarding the  studies tabulated are warranted   Cursory

 ?>1 Sercertl  Is  slight y acid  (pH  5'.0±1.0) and  contains lea heavy
 ieta?s  <  eilept  for iron which is  co-only present in levels
 of 1,000  ppm.

 The data  presented from the Solid and Hazards  Waste Research Labo-
 ratory were obtained at the Boone County Field  Site Test Cell ' v'nicn
 contains  3S5 tons of municipal  solid waste  compacted  to 592 kg/m-
  (1,000 Ib/yd*).17  jest Cell 1  was  constructed  in 1971 in accordance
 with best available sanitary landfill technology at that  tin:e.

  The data reported from the University of Illinois were obtained  under
  U.S.  EPA Research Contract 63-02-0162.  The leachate was  generated
  from a laboratory lysimeter, 1.22 m diameter (4 feet), containina
  1,520 ka (3,358 pounds) of shredded solid was us, 33 irai (1.5 inch)
  grate opening, compacted to 330 kg/m3  (556.9 Ib/yd').  Water was

                                                                        TABLE 11

                                                                UACHATE  COMPOSITION
F '

!-.• - -VIsS
UV. 'J-P
•.s1 -s
1 n"**' t* — M
" i :"
16. ooo-::. ooo

5 '-6 i
6 .000- 9 .COO

>.oTVt All flrurus in M»

Kl<0-2 , JOO










A i





, 700-10. 6S(
















TABLE IT (Continued)
Nil, -il
vi'«;o -N















2355 '















4 7



W.VA. U.(10)







420 .



t *



7930 •


• .

40- 89,520
81- 33,360
256- 28,000
3.7- 8.5
0- 59,200
10- 700
2810- 16,800
0- 20,850

0- 130
6.5- 85
0.09- 125
0- 370
0- 9.9
<0. 10-2.0

applied doily to bring the solid waste to field capacity within 30
days, and thereafter en equivalent of 0.89 mm/week' (0.035 in) was
added to generate sufficient leachate for evaluation of leachate
treatment methods.

Leachate data reported by Drexel v/cre obtained under U.S. EPA
Research Grant RC00777.  The solid v/aste used was not processed; the
laboratory column was 1.83 m (6 feet) square, and initially was packed
2.44 m (8 feet) deep.29

Data presented from Georgia Institute of Technology are from ongoing
U.S. EPA Research Grant, RS01397, to investigate the feasibility of
recirculatir.g leachate back through the landfill as a treatment
method.  Again, the simulated landfill conditions were utilized for
study purposes.  The refuse was compacted into a 3.05 m x .915 m
(10 ft x 3 ft) column in two 1.52 ni (5 ft) lifts to a dry density
of about 318 kg/m3 (535 lb/yd3).  To expedite the production of
leachate, 948 1 (250 gal) of tap water v/ere added after placement of
the soil cover.  A more detailed description of the project and the
results to date are provided by Pohland and Mao.18

The 01 in Avenue data are from the work done at the University of
Wisconsin to determine the treatability of leachate using a variety
of classical treatment methods.  From this work the concept of anae-
robic digestion followed by aerobic polishing v.«s formulated snd led
directly to the pilot plant studies that are still ongoing at a land-
fill in the Milwaukee area.  The original laboratory scale studies
ere available in a progress report for the period June 1, 1970 to
August 31, 1971, entitled "The Treatability of Leachate from Sani-
tary Landfills,"19 authored by R. K. Ham under U.S. EFA Research Grant

The DuPage and Winnetka data were taken from Hvc'rocsolosy of Solid
Waste Disposal Sites iji Northeastern .Illinois.*u  SpedffcaTly,
groundwater quality in the near vicinity of sanitary landfills is

Research was conducted by Merz21 at Riverside, California, in a test
bin.  This represents the earliest extensive leachate study.  The
basic constituents identified appear to agree with the most recent
analysis of leachate.

The data presented for the Mission Canyon landfill22 gives a good indi
cation of the age factor when analyzing leachate.  As can be seen
the early leachate analyses reported high COD and EOD5 values very
typical of fresh leachatcs.  Some 3 years later the effects of age and
materials are noted in the low COD—all readily oxidizable organics

already removed--and the BOD5 is also low indicating material re-
miring if^fconducive to Siolocjical degradation  or tnat not much
naterial is even there.  The significant increase in chlorides,
sodium! and ^Sssliun over a 3-year period compared to decreases in
all other parameters is interesting but unexplained.

The Sonoma data23 are from an ongoing Demonstration Grant l-GOG-EC-00351
Conclusions have not as yet been made; the data are presented to in-
dicate  the effect of high moisture throughput on leachate charac-

Another study  using shredded solid waste, but 1n combination with
unshredded solid waste, was conducted by Qasim and Burchinal .2"

Chian,  et al.25 reported on the characteristics of two >achate  sam-
nles  provided  by R. K.  Ham at the University of Wisconsin.   The  in-
SSseTsilld  waste surface area and lack of cover "tcrial  has  a
drastic effect on  increasing the quantities of materials leacned.

A detailed  characterization  study by Chian and DeHalle" showed  that
the majority,  78 percent,  of the organic matter  in J«*h leacha^e,
 Figure 6.  consisted of low molecular weight compounds, /B percent
of which was free volatile fatty acids;  also,  significant Counts
 of the heavy metals wore chelated  by the humic carbohydrate-like
 Urge modules and the fulvic acid snail molecules   Leac  ate from
 an old landfill, Figure 7, was found to consist  almost entire y of
 small molecules of fulvic acid and hsalc-llke  materials capable or
 chelating heavy metals; no free volatile fatty acids were detected.

 Heavy metal concentrations listed in Table 11  are  generally less  than
 1 Sg/1.  Table 12 indicates the solubility of several heavy metal
 salts  in water.  The extent to which a substance will dissolve  in
 another varic-s greatly with different substances and  dcpcnos on tne
 nature of the solute  (in this case  the heavy metals)  ana  solvent, the
 Kature.  and the  pressure.  In  general, theeffgt  of  pressure
 on solubility is small unless gases arc involved.   However, the effect
 of temperature is usually very pronounced, as can be seen  from  tne
 table  of solubilities  for various temperatures.

  In general, compounds of  similar chemical character are more readily
  soluble  in  each other than are those whose chemical  character is  en-
  tirely different.   As presented'in  the  table, inorganic ma..erials are
  dissolved  in  water,  some  to a  large extent because of chcaical  simi-
  larities,  some hardly at  all  due  to vast chemical differences.

  The substances presented  in the table  were selected as representative
  of those that have the highest interest at this tirr.e.  The tabulated
  data arc for water at or near pH  7.0.   When  applying these figures

 32Cp  48 r  80Cp

I 200


     r 42-  700
         - .600

Ǥ  80

     -o 18

     -" 12
     -  6
     l-  0
               —   /-Carbonyl
          -  30C
         - 200
          -  IOC
f J\ r-Phenolic OH
r\ / w

              I \l\  \   \
/-Carbohydrate    /  // / \v\ \  \
          >-   0
                                                                   SO  -i
                                                                   30 o-
                                                                   -tU n
                       (f   /-Corboxyl fc^V





                                  Elution Volume, ml


                                                                               18   -i 18
                                                       JY            «  \_ ».-
                                           >o—o-T^-*0/v i^Corboxyl '   o-V"
                                          0        \   /   \ i                 *!~~"
                                          icnolicOH^- .'    \!	s    ..L.
                                           1       t~»m^     ^     ^^^^^•^^•^^•••'•'••^•^ ^~^
Figure 7.


Fed 3
0 C
20 C
40 C
100 C
• 73.0
aThis table shows the amount of substance  (anhydrous) which is soluble
 in lOOg of water at the temperature 1n degrees centigrade.

Adapted from Perry's Chemical Engineers*  Handbook, Fourth Edition,
 McGraw-Hill, flew York.   1950.

cParts by weight of substance  soluble  in 100 parts by weight in water.

Measured at 25 C.

 to leachate some variances should and will  be expected.   In  leachate
 the pH is usually toward the acidic side of the scale,  pfl 5.0  to 5.5,
 and thereby significantly affecting microbial and chemical reactions
 acting on the heavy metals.  Ionic and r.onionic materials also  in-
 fluence the overall solubility scheme of a  particular metal.   Addi-
 tionally, the dissolved solids along with the potential  buffering  .
 effect of the carbonate-carbonic acid  and  the volatile acid systems
 further increase the likelihood for deviation from the  pure  water
 system.  Thus, it can be stated that the table gives an indication
 of the solubility of certain metal compounds in water at different
 temperatures and some inferences can be made from them  regarding
 heavy metal concentrations in leachate.

 Extensive bacteriologic content of "leachate 1s not available.   Fecal
 colifonn and fecal streptococci data from the Boone County  Field Site
 are presented in Figures 8 and 9.  Unpublished data26 obtained from
 the Illinois laboratory study25 indicate a similar trend of  high
 numbers of initial vecal coliform and fecal streptococci, follcv.-cd
 by a gradual, but definitive oec-iine to very lev; numbers cf  bacteria.
 Peterson27 has reported isolation of poliovirus from a  laboratory
 landfill.  Thus the public health importance of leachate discharge
. to a stream is further supported, since an operational  landfill will
 continually receive new pathogen-containing solid waste.

 The relative environmental significance of leachate Is  difficult  to
 determine on a national basis cue to the specificity of site condi-
 tions that control the moisture regircen and hence, leschate and gas
 production.  The following hypothetical example is offered for
 illustration; it represents a typical case east of the  l-'iississippi
 River  {Figure 4).  It does not represent a worst case condition,
 Pierau1" measured  leachate production at 0.9 imi/day (12  in/year).   A
 rule of thuirb for  annu?l utilization of landfill soace is l.SSrn/ha/
 10,000 population  (15 acre feet per ,10,000 population).  Landfill
 depth of 4.56 m  (15 ft) is not unusual.  Leachate then  is
 123 1/cap/yr  (32.6 gal/cap/yr).   If one assumes a solid waste  gen-
 eration rate of  970 kg/cap/yr  (2,000 Ib/cap/yr), then from  Rovers and
 Farquhar,23 the  annual  per capita  extraction of materials from solid
 waste  initially  at 30 percent moisture by wet  weight would  be  2.58 -
 7.8 kg (5.7 to 17.2 Ib) COO,  16.1  -  33 kg  (35.6 to 72.8 Ib) 80DS.
 0.137 - 2.6 kg  (0.3 to  5.7 Ib) chloride, 0.0318  - 1.0 kg (.07  to
 2.2 Ib) ammonia  nitrogen,  0.0310  -  0.59  (.07  to  1.3 Ib)  organic
 nitrogen, and 0.136 -  1.31 kg  (0.3 to  2.9  Ib)  sulfate.    The duration
 of this rate  of  extraction is  not known  but  would eventually  de-
 The  above  ranges  of leached material  quantities were determined ex-
 perimentally  over finite tine periods.   Fungjroli  and Steiner29
 have indicated  a  relatively constant  leaching  phenomenon;  the quantity

 0  10'

1    ,
~  10
•• 10
                   WINTER    SPRING     SUHMER       FALL  WINTER     SPRING
      0      10      20       30        40       50      60      . 70      80       90

                                                VTDCS FROM 9/1/71


c 10<

§ 1
a •
£  10*

g  10'
 • 10'
       FALL   W1STER    S?RIXC
10       20  _    30    .  .40       50       60  .-   70

                               WEEKS FROM 9/1/71








                        Cw&IATXVB CKAXS/FT.2 KZXOVEO
                        VS. QUANTITY OF LEAOlATE/FT.2
                                               i  i i .1
                                                        I  '
*.  After Fungaroli £ Scelner
               ion of Sanitary
    Report nubsictcd to Solid
    and Hazardous Waste F.cucarch
    Labora;oj:y for Research Grant
   'R800777  Oct. 1973.

b.  Field capacity reached at
    30 liters per ft.2 test.)
                                                                         CUMULATIVE  CHLORIDE LEACHED4•
                                                  Figure  10.

of materials leached  per unit surface area is related to the leaching
volume per unit surface area.  Typical results are shown in Figures
10, 11, and 12.  The  duration of  this study indicates sanitary land-
fills have a long-term effect on  the environment.










 y \i**vvcc
                           t   t  I  i  I l I
                                                   ]     11
                                                             COJUUTIVE HARDNESS LEACHED0
                                              Figure  11.

                                                                       After Funs/iroli 4 Srelncr
                                                                       "InvcsclRstioa of Sanitary
                                                             «i:ill Echavior"
                                                                       Report suVT.ittc

1   Rcmson,  I.,  A.  A.  Fungaroli,  and  A.  W.  Lawrence.   Water tloven-.ent
    in an Unsaturated  Sanitary Landfill.  Proceedings  of the Am.  Soc.
    of Civil  Engrs.  94(SA2):307-316, April  1963.

2.  Fenn, D.  G., and K, J.  Hanley.   Use  of the Water  Calance I'ethod
    for Predicting Leachate from Sanitary Landfills.   Unpublished
    manuscript.   Office of Solid Waste Management Programs, U.S.  EPA.
    June 1973.  59 p.

3.  Salvato,  J.  A., W. G. Wilkie, and B. E. Mead.  Sanitary Landfill
    Leachate Prevention and Control.- Journal WPCF.  43_:2084-Z100,
    October 1971.                            -

4.  Sanitary Landfill Studies:  Appendix A—Sundry of Selected Pre-
    vious Investigations.  California Department of Water Resources,
    Sacramc-nto.  1S59.  115 p.

 5.  Frevert, Schwab, Edminster, and Barnes.  Soil and Water Conserva-
    tion  Engineering.  Wiley.  1963.  439 p.

 6.  Brunner, D. R., and D. J. Keller.   Sanitary Landfill Design' and
    Operation.  U.S. EPA, Washington, D.C.   Publication SW-6bts.
    1972.  p. 17.

 7.  Design of Small Dams.  1st ed.   Washington, U.S.  Govt. Print.
    Off., 1960.  611 p.

 8.  Fungaroli,  A.  A.   Pollution  of Subsurface  Water by  Sanitary  Land-
    fills:   Vol.  1.  U.S.  EPA, Washington,  D.C.   Publication S!.'-12rg.
    1971. 131  p.

 9.  Hughes,  G.  M.   Hydrogeology  of  Solid Waste Disposal  Sites  in
    Northeastern Illinois.   Office  of Solid Waste Management Programs,
    U.S.  EPA,  Report  SW-12d,  Washington, D.C.   1971.

10.  Kerz, R.  C.  Final Report on the Investigation of Leaching of a
    Sanitary Landfill.  Publication Number 10, State Water Pollution
    Control  Board, Sacramento,  California.  1954.

11.  Sonoma  County Refuse Stabilization  Study; Second Annual  Report.
     Department of Public Works,  Santa Rosa.  1973.

12.   Schoenberger, R.  J., and A.  A.  Fungaroli.  Treatment and Disposal
     of Sanitary Landfill Leachate.   _In_ Proceedings:   Fifth Kid-
     Atlantic Industrial Waste Conference, Drexel University,
     Philadelphia.  1971.

13.  Pierau, H., and G. Muller.  The Significance of the Hygienic Un-
     objectionable Disposal of Activated Sludge Together with Domes-
     tic Refuse.  Stadthygiene [German] 21^ 82.  1970.

14.  Pierau, H.  Results of the Investigations of Test Fills and Exist-
     ing Disposal Sites.  The Stuttgarter Journal of Civil  Engineering
     [German] £L_ 27.  1968.

15.  Klotter, H. E., and E. Hantge.  Disposal of Refuse and the Pro-
     tection of Grcundwater,  Refuse and Waste [German] 1 ^  1.  1969.

16.  Knoch, J., and R. Stegman.  Experiments of the Treatment of Land-               ,'•
     fill Leachate/  Refuse and Waste [German] 6^ 166.  1969.                        ...
                                      ------                       .                   ! i
17.  Leachate Generation and Composition:  Test Cell 1, Boone County                  •'
     Field Site.  Solid and Hazardous Waste Research Laboratory, U.S.                 '
     EPA, Cincinnati".  May 1973.  20 p. (manuscript)

18.  Pohland, F. G., and M. C. Mao.  Continuing Investigations on
   •  Landfill Stabilization with Leachate Recirculation, Neutraliza-
     tion, and Sludga Seeding.  Progress report to Solid and Haz-
     ardous Waste Rssearch Laboratory for Research Grant R801397.
     September 1973.  79 p.

19.  Boyle, W. C., and R. K. Ham.  Treatability of Leachate from Sani-
     tary Landfills.  Paper presented at 27th Annual Purdue Industrial
     Waste Conference.  1972.

20.  Hughes, G. M.  Hydrogeolcgy of Solid Waste Disposal Sites 1n
     Northeastern Illinois.  Office of Solid Waste Management Pro-
     grams, U.S. EPA, Report SVM2d, Washington, D.C.  1971..

21.  Merz, R.C.  Final Report on the Investigation of Leaching of a
     Sanitary Landfill.  Publication Number 10, State Water Pollution
     Control Board, Sacramento, California.  1954.

22.  Meichtry, T. M.  Leachate Control Systems.  Los AngeTes Regional
     Forum on Solid Waste Management.  May 1971.

23.  Sonoma County Refuse Stabilization Study; Second Annual Report.
     Department of Public Works, Santa Rosa.  1973.

24.  Qasim, S. R., and J. C. Burchinal.  Leaching from Simulated
     Landfills.  Jour. Water Poll. Control Fed.  42, pp. 371-379.
     March 1970.                                 	

The following section has been reproduced from:



SITES", OSWMP, U.S. EPA, October 1975,


                            TABLE  3

                       RUNOFF  COEFFICIENTS*

   Surface conditions                    Runoff coefficient
Grass cover:
Sandy soil ,
Sandy soil,
Sandy soil,
Heavy soil,
Heavy soil,
Heavy soil,
flat, 2%
average, 2-7%
steep, 7%
flat, 2%
average, 2-7%
steep, 7% .
, 0.13
- 0.10
- 0.15
- 0.20
- 0.17
- 0.22
- 0.35
     * Chow, V. T., ed.  Handbook of applied hydrology;  a
compendium of water resources technology.  New York, McGraw-Hill,
[1964].  Iv.  (various pagings).

        Water Balance Calculations for a Sanitary Landfill

     As shown in Figure 2, the water routing through a sanitary
landfill basically consists of two phases—routing through  the
soil cover and routing through the compacted solid waste beneath.
The soil cover is that phase which interfaces directly with the
atmosphere and will determine the amount of infiltration into
the soil and percolation into the solid waste.  The solid waste
phase and its attendant moisture storage capacity will determine
the quality and time of first appearance of the leachate.
Therefore, a water balance can be performed on the soil cover
phase to determine the amount of percolation.  The solid waste
phase can then be analyzed in relation to  the percolation amounts
to determine the extent of potential  leachate problems.

     Treating  the moisture regime of  the soil cover as a one
dimensional system, the water balance method can be used to
calculate the  percolation of water  into  the solid waste.  In
applying the method,  the  surface  conditions of the  sanitary
landfill site  must  be well defined.   The type and thickness
of  the  cover  soil,  the presence or  absence end type of vegeta-
tive  cover, and the topographical  features are the  primary
surface conditions  that will  affect percolation.

 Precipitation (P)        .,
^tX                       Vegetative
      Surface Runoff (R/0) '  ^/ Cover
     r     ^-             r
                                  Infiltration  (I)
                      Soil Moisture Storage
                                                                Phase I
                                                               Phase IT
          Figure 2.  Sanitary Landfill Water Balance

     To best illustrate the water balance of a sanitary landfill.                  \
three case studies have been selected to reflect various climatic                  ,;
and soil conditions.  Cincinnati, Ohio, was selected to represent
a humid climate with a sandy type soil; Orlando, Florida, to
represent a humid climate with a sandy type soil; and Los Angeles,
California, to represent a dry climate with a fine qrained soil.                   •.

     Conditions will vary among sites and among the stages of
a given site's life.  These conditions must be considered in
applying the water balance method.  For illustrative purposes,
the water balance analysis was simplified by the following
basic assumptions:

     1.  The landfill has been completed with 0.6 meters (2 feet)
of final cover and graded with a 2 to 4 percent slope over most
of the surface area.

     2.  The solid waste, cover soil, and vegetative cover were
emplaced instantaneously at the beginning of the first month
of the computation initiation.  Practically speaking, this
ignores any percolation that may occur prior to the placement
of the final cover soil.

     3.  The final use of the site is an open green area to be
used for recreation or pasture.

     4.  The surface is fully vegetated with a moderately deep-
rooted grass, the roots of which draw water directly from all
parts of the soil cover but not from the underlying solid waste.

     5.*  The sole source of infiltration is precipitation falling
directly on the landfill's surface.  All surface runoff from
adjacent drainage areas is diverted around the landfill surface.
All ground water infiltration is prevented through proper site
selection and design.

     6.  The hydraulic characteristics of the soil cover and
compacted solid waste are uniform in all directions.

     7.  The depth of the landfill is much less than its horizontal
extent.  Thus, all water movement is vertically downward.

     The water balances for the three case studies are presented
and depicted in Tables 4, 5, and 6 and Figures 3, 4, and 5 for
Cincinnati, Orlando, and Los Angeles respectively.  In order to
fully understand the calculations and manipulations involved in
the water balance procedure, refer to the Appendix which presents
the basic calculations, a discussion of each of the parameters
and their manipulations, and copies of the three soil moisture
retention tables used in the calculations.


                                       TABLE  4
                          HATER BALANCE  DATA FOR CINCINNATI. OHIO
Parameter *
ST (Table C)


0 N
51 17
65 83
0.13 0.13
8 11
57 72
+6 +55

39 94
+6 +55
51 17
0 0



- — . 	
        The parameters are as follows:  PET, potential evapotransplration;
P, precipitation; CR/Q surface runoff coefficient; R/0, surface runoff;
I, Infiltration; ST, soil moisture storage; AST, change in storage; AET,
actual evapotranspiratlon; PERC, percolation.  All values are in millimeters
(1 inch = 25.4 mm).  See Appendix for discussion pf parameters.

                    A     M     J     j     A     S     0
             Figure 3.   Water  Balance for  Cincinnati,  Oh

        Percolation                     g.
        :Soil Moisture Recharge

  /////Soil Moisture Utilization


A Actual Evapotransp?ration

                                         TABLE 5
Parameter *
ST (Table A)


/ -
..* J
v ....


' 84



        *See footnote, Table  4.
        *The situation where  a positive  I-PET value  occurs between two negative
values Is a special case.  Here,  ST is found by direct  addition of I-PET to the
preceding ST.  TheiNEG  (I-PET) value Is then found  from the soil moiature
retention table for the  ST value.

                                J     J
            Figure k.  Water Balance for Orlando, Florida

IN I|III Percolation                    6	0 Infiltration

        So?1 Moisture Recharge

             Moisture Utilization
                                         	£ Actual Evapotranspiration

                                 TABLE 6
ST (Table B)
. 34.


. 0
-71 .-
-138 •
u -,
. 1
H ••



See footnote. Table 4.

                        J     J

  Figure 5-  Water Balance for Los Angeles, California

Soil Moisture Recharge         6	3 Infiltration

     Moisture Utilization      &— -^Actual Evapotranspi ration

     Table 7 presents a summary of the water balances for the
three case studies.  As expected, the locations in the humid
areas experienced percolation while the dry location experienced
no significant percolation:  It is interesting to note that all
three cases are characterized by at least one wet season and one
dry season during the one-year cycle.  However, only 1n the humid
areas is the precipitation sufficiently greater than the evapo-
transpiration to exceed the soil moisture storage capacity and
produce percolation.

     The fluctuating nature of percolation during the one-year
cycle is an interesting phenomena to analyze.  For example,
examine the percolation in Cincinnati.  During the dormant season
(December to April), little or no evapotranspiration occurs,
resulting in a high soil moisture content and significant amounts
of percolation.  During the growing season (Nay to September),
the large evapotransplratlon demand utilizes all of the Infil-
tration moisture.  The effect of the soil moisture storage 1s
clearly seen in the fall months of October and November when the
infiltration exceeds the potential evapotranspiration.  This
excess infiltration recharges soil moisture storage, resulting
in no significant percolation until December.  The fluctuating
nature of percolation will cause variations in leachate generation.

                        Lcachate Generation

     Knowing the amount of water that percolates through the
cover material (phase I), an analysis of the water routing
through the solid waste (phase II) can now be performed to
determine the magnitude and timing of leachate generation
(refer to Figure 2).

     Like its cover material, the underlying, solid waste cells
(including the relatively thin layers of daily cover material)
will exhibit a certain capacity to hold water.  The field capacity
of solid waste has been determined by many Investigators to vary
from 20 percent to as high as 35 percent by volume. •*»'*  In other
words, the field capacity would vary from about 200 mm water/meter
refuse (2.4 inches/foot) to about 350 mm water/meter refuse
(4.2 inches/foot).  For present purposes, a value of 300 on/meter
(3.6 inches/foot) will be used.

                                   TABLE 7
	Parameters - mean annual  (mm)	
Precipitation  Runoff  Infiltration AET  Percolation


Los Angeles,




 872      658     213

1243     1172      70

 334      334       0

      The amount of water which can be added to the solid waste
 before reaching field capacity depends also on its moisture
 content when delivered to the landfill site.  This value will
 vary over a wide range depending on the composition of  the waste
 and the climate.  Several analyses performed on municipal solid  waste
 show its n>Qi?*ure content to range anywhere from 10 to  20 percent
 by volume.J''*'IJ  A moisture content of 15 percent by  volume
 or about 150 mm/m (1.8 inches/foot) will be used here.  Therefore.
 with a field capacity of 300 mm/in and an initial moisture content
 of 250 mm/m the compacted waste would have an adsorbtion capacity
 of about 150 mm of water per meter of solid waste (1.8  inches/foot).
      Theoretically, the water movement through a compacted solid
 waste cell will act like water movement through a soil  layer.
 In other words, the field capacity of a given solid waste level
 must be exceeded before any  significant leachate to a lower  level
 will occur.  For the examples, this means that 150 mm of percola-
 tion would have to be applied to a municipal solid waste layer
 one meter deep before any significant leachate would be generated
 from the bottom of that layer.  Practically speaking, due to the
 heterogeneous nature of the  solid waste, some channeling of water
 will occur causing some leaching to occur prior to attainment of
 field capacity.  However, this amount should be small and certainly
 not a continuous flow'and will be assumed negligible.

      Employing the above concepts, one can assess  the extent of
 the leachate problem for a given sanitary landfill  site.  The time
 of first appearance of leachate would be influenced by  the land-
 fill's  depth and the leachate quantities by the landfill surface
 area (size).  Figure 6 shows  the relationship between annual
 percolation amounts  and time  of first appearance of leachate for
 various landfill  depths.   Figure 7 shows the relationship between
 annual  percolation  amounts and leachate  quantities  for  various
 size landfills.
                                 •                                 ',
      This  methodology  will be illustrated  by application to the
 three case studies.  Equal amounts  of solid waste will  be
 assumed for all  three  cases in determining  the  relative depths
 and  acreage requirements  at the  different  locations.

    .  Case  1--Cincinnati.  Ohio.   The  landfills  in this location,
 as in most  of  the northern part  of the country,  are generally
 trench  operations or area fills  in  small ravines.  The depth
 of these operations would be  expected  to range  between  10 and
 20 meters, with  the surface area usually above  50 acres (ca.
 2X10V).  A site will  be assumed  here with  an  average depth of
 15 meters and  a  surface area  of  202,000 mz  (50  acres).  Therefore,
with  an average  annual  percolation of slightly more than 200 mm

               Figure 6.  Time of  First  Appearance of Leachate *
      200 ''  — I —
      100 .
                                                 Depth of Landfill (meters)
                                           TIME (Yrs.f
                  +Based on a solid waste moisture absorption capacity of 150 mm/m.

                   Time  zero is  defined as that  time when  the field capacity of the

          soil cover  is  first exceeded, producing the  first amounts of percolation.

                  Figure 7.  Annual  Leachate Quantities

                          After Tine of Rrst  Appearance
     300 • •
     200 •  — I -  -f	
                                                        _.   of Landfill
                                                        Surface (ra^x 104)
                      20           *«           60            80

                             Leachate  Quantity  (liters/year x 10*)

(Table 4), it would take close to 11 years  (Figure 6) for signi-
ficant amounts of leachate to appear at the bottom of the fill,
at which time the average annual  leachat.p nuantitv wnnin KQ atinn
                                                    would be about

 ,    Case 2--Orlando. Florida.  The depth of landfills in this
 location and most or the coastal United States are limited due
 to proximity of the water table to the ground surface.  The
 regulations of most state agencies prohibit dumping of solid waste
 directly into the ground water and, in fact, require a few feet
 hnt^1SJU^ed,S°il-??tween the h19" 9round water level  a"d the
 w?ft°!.?f Jh? landfl11-  Wl'th these restrictions, most landfills
 will fin below ground only one or two meters and above  ground
 as high as availability of cover material  will  allow.  Assuming
 an average depth of 7.5 meters, only half the depth as Case 1,
 A ?n§U5taceTarea rea.ui>ed W0"ld be doubled to 100 acres  (ca.
 ?n   m,|-  Therefore, if the average annual  percolation  is
 70 mm (Table 5), it would take  close to  15  years for  signifi-
 cant amounts of leachate to appear (Figure 6),  at which  time
 the average leachate quantity would be about 30 million  liters/
 year (Figure 7).

 „   Case 3-Los Angeles. California.   The landfills in  this
 ?r"  are generally  area fills  in  deep  canyons with  depths ranging
 between 30  and  60 meters.   Assuming an  average  depth of  40 meters,
 the surface  area required would only be about one-fourth that of
 £ nJi'^-J  3C!;eS  (ca-  5xl0^2)-   As  n°ted in Table 6, percolation
 is negligible and one can easily  assess the  leachate problem as
 being insignificant  for  such a  location.

     A  summary of the results for the three case studies is
 presented in Table 8.

     Analysis of the sanitary landfill water balance calculations
 presented above points out some very interesting aspects of leachate
 generation of importance to the design engineer.  These aspects
 should be considered in the overall assessment of the oroblem
 and may enter into the selection and design of leachate control

     First, in most cases leachate generation presents  a  potential
problem principally in humid (low AET and  high precipitation) areas
of the country.   Therefore, except for those sites where  irrigation
is utilized (discussed later), leachate problems will be  virtually
nonexistent at sanitary landfills  in arid  parts  of the  country

                             TABLE 8

                         Time of first           Average
   Location               appearance           annual  quantity
                           (years)      ,      (liters/year)  x 10
Cincinnati, Ohio             11                       4O
Orlando, Florida             15                       30
Los Angeles, California      —                        0
     Second, there may not be a continuous flow of leachate throughout
the year.  Percolation and generation of leachate will  most likely
follow a pattern similar to that of the precipitation.   This will
result in the major portion of the leachate being produced during
those months of significant percolation, with much lower flows
occurring during the rest of the year.

     Third, there will be a variation in the leachate generation
pattern and amounts fron year to year.  The water balance cal-
culations presented in this paper use mean monthly climatic values
determined over a 25-year period.  However, a brief analysis of
precipitation data for any given location will Indicate significant
variations from year to year.  So, while the average year might
indicate a relatively minor leachate problem requiring little
or no leachate control measures,'an above average year may result
in an entirely different assessment of the problem.  Therefore,
the engineer may wish to base his design on monthly precipitation
values higher than the average values in order to provide a factor
of safety in the estimation of leachate flow.

                      Other Considerations

     The above methodology is presented with the Intention of
being a basic tool for engineers in assessing and designing
sanitary landfills.  The presentation was purposely kept straight-
forward since the concern was more to develop a clear understanding
of the basic concepts and methods involved rather than a full
scale design manual that would assess leachate problems for all
conditions in all areas of the country.


Precipitation percolates  into materials  deposited  in  a  solid-

waste landfill  and  lixiviation  (dissolving  of

soluble components) produces a  solution called leachate.

The landfill  leachate under conditions where infiltration

is greater than runoff  and evapotranspiration combined,

moves downward  through  refuse,  and through  underlying

soil and sediment until it reaches an  impermeable layer

or ground water.  In  its journey,  leachate  traverses

three zones of  geochemical activity with certain

characteristics which are shared and others which are

unique to each.  The  ensuing discussion will attempt  to

describe some of the  characteristics in each of  the zones

and ways in which they  interact with the constituents of



Solid waste deposited in municipal landfills is  a

heterogeneous mixture of organic and inorganic materials

and living organisms.   Upon deposition, and frequently

before, microbial activity begins the  degradative process

on organic matter.   The microbial decomposition  of  organic

matter is encouraged by moisture and warm temperatures.

Moisture is provided through precipitation, and temperature

increases from the release of energy from oxidation of the

organic substrate.  Temperatures as high as 120°F have

been observed in sealed test cells filled with mixed refuse.

Under aerobic conditions temperatures as high as 190°F have
been observed.

The microbial activity soon uses up the supply of oxygen and

causes the refuse beyond the zone of rapid air diffusion

to go anaerobic.  Anaerobic conditions cause the end

products of decomposition to be somewhat different from

carbon dioxide and water which are the products of complete

oxidation.   Notable among the products of anaerobic

decomposition is methane gas.  Other organic anaerobic

decomposition products such as alcohols, aldehydes, and

thiols tend to be more odoriferous than their aerobic

counterparts.  Of particular importance with regard to

leachate are the anaerobic forms of sulfur, nitrogen, iron,

and manganese.  Sulfur is present as sulfide, nitrogen as

ammonia,  iron in the ferrous (+2)  form, and manganese in

the manganous (+2)  form.  The latter two metals are more

soluble in their reduced forms than in their oxidized forms.

The decomposition process provides carbon, hydrogen,

nitrogen, oxygen, sulphur, phosphorus, and some metals

which are fixed by microorganisms in their tissues.

Metabolic products and some inorganic residues from

organic decomposition are released to percolate.

The percolate flows downward through the refuse which is

in progressively advanced stages of decomposition, and

it passes through layers of buried cover material.

Percolate shows a net gain in dissolved constituents as

it progresses downward, but may lose some individual ions

from cation exchange or other reactions encountered en

route.  Attenuation of percolate constituents within

the landfill is not well documented, therefore

predictions concerning it must be based upon known

geochemical principles and final leachate composition.  The

attenuation within the refuse zone is not of immediate

practical importance because those species which are

attenuated are not contributing to ground-water

contamination.  However, some discussion of processes

occuring in the refuse zone is important as it assists in

the interpretation of leachate composition.

Elements which are fixed in raicrobial tissue will not be

mobilized until the microorganisms die and the cells break


down.  Even then, some of the compounds released are only

slightly susceptible to further biodegradation, and

represent a stabilized organic material much like soil

humus,  humus-like material is also a product of refuse

decomposition.  This material is a polymeric organic

colloid with various chemically active functional groups,

such as acid, alcohol, and phenol, which can react with

metal cations to form complexes.

In this way, metals may be sorbed on the organic colloid

and removed from solution.  Cation exchange reactions occur

in a manner similar to the exchange reactions occurring

with clay which are discussed below.

Nitrogen present in refuse organic matter is released in

soluble form with microbial decomposition.  In organic

substances, nitrogen is in a chemically reduced state.

With aerobic decomposition, the nitrogen is oxidized to

nitrate ion.  Under anaerobic conditions, nitrogen is
released as amonium ion.
                         3 )
     Aerobic: 2 CH CHNH COOH + 70 	> 3CO2 + 7H2O + NO3    (1)
                  •3    £.         £•

     Anaerobic: 0.33 C H ON + 0.073 HCO" + 0.64 HO—£0.33
                      46              3         2

                NHj +0.14 CH COO" +0.13 C H COO~ + 0.133

                C H COO" + 0.193 CO                        (2)

 Anaerobic conditions are predominant  in  landfills.  Thus,
 most  nitrogen  in  leachate is present  as  ammonium.  Nitrate
 which is  formed aerobically may  be  reduced through
 denitrification to molecular nitrogen when it passes
 through anaerobic zones.   The relatively small amount of
 nitrate produced, coupled with probability of denitrification
 explains  the typically low nitrate concentration in leachate.

 Nitrogen  is released only  if  it  is present in quantities
 exceeding the nutritional  requirements of the microbial
 population effecting organic  decomposition.   The requisite
 amount of nitrogen can be expressed in relation to carbon.
 Carbon/nitrogen ratios up to about 10/1 will  result in
 nitrogen release.   Above that, most of the nitrogen will
 be  fixed in microbial tissue.  Fresh organic  matter would be
 expected to release  nitrogen during decomposition,  whereas
 carbonized ash  would  not be.

 Organic decomposition releases carbon  dioxide in  large
 amounts under aerobic conditions, and  in  smaller  amounts
 under  anaerobic conditions.   The  enrichment of the
 interstitial gas in refuse by carbon dioxide  results in
production of bicarbonate  ion as  follows:

     C02 + H2°  '" "  "  H2C°3

         H2C03  ;==—  H+ + HC05                      (4)

         HC03   ^	 H+ + C052                      (5)

Only when the pH exceeds  9 does reaction (5) occur to

a significant extent,  (about 20)percent.  '  The production

of carbonic acid  (4)  is proportional to the partial

pressure of C02 in the atmosphere in contact with the water.

The carbonic acid ionization to bicarbonate  ( 4)  is

proportional to the carbonic acid concentration.  Only  a

small fraction of the carbonic acid in the system is


Bicarbonate is frequently a major anion in leachate.

ecause of the reversible reactions  (4) and  (5),  when

present, bicarbonate acts as a buffer and tends  to prevent

large fluctuations in pH.

Other organic decomposition products include  carboxylic

acids (acetic, isobutyric),phenols  (phenol, p-cresol),  and

amino acids (glycine, alanine) which can form ring complexes

(chelates) with heavy metals, rendering them  soluble  and

protected from adsorption.5'6^Movement of heavy  metals  with

percolate may be possible to a large degree because of  such

complexes  (Figure  3-8	).   The  distance  over which chelated

metals move  depends  upon  the chemical  and biochemical

activity encountered.   Some chelates change ionic charge

with changes in  pH.  Thus,  if a change in pH in percolate

occurs, the  chelates may  be adsorbed or  otherwise

deposited.   Microbial  decomposition of the organic portion

of the molecule  leaves the  metal cation  behind where it is

prone to adsorption  or precipitation.  If  the chelated

metal encounters no  conditions  which affect it, it will

be transported to  the  ground water.

Heavy metals in  landfills are primarily  in their metallic

state and are not  soluble  .   The exception is with

deposition of soluble  heavy metal salts  either as solids or

in solution.  These  may come from certain industrial

activities such  as electroplating or metal pickling.  Most

heavy metals occur in  solution  as cations  (positively

charged), but a  few  are usually present  as anions  (negative-

ly charged).  Those  usually occurring  as anions are chromium

and vanadium.  Included with heavy metals, but chemically

somewhat different are arsenic,  boron, and selenium which

occur as anions.

A minor complement of  heavy metals is  present in the

combustible  (decomposable)  fraction of urban refuse.  In


 Gerayhcv & MUler, Inc.
                   ADENOSINE- 0- P'
                                 \  /       c	o
                                   M        I   »  \
                                            I   >"i   ^
                                           HC — 0 — M

                                           HC	0

       FeOTDSALICYLATE                    TARTRATE


                        — CHELATES —
                     CLAY   MINERAL
                                           REMAINDER OF

                                           HUMIC COMPOUND
                                     AFTER STEVENSON AND ARDAKANI, 1972
Figure 3-8
                                          tfLf,f „
                                           *" " * f J *^

this usage, minor means  concentrations  in parts per million

as contrasted with  percentages  as  represented by metallic

wastes.  These heavy  metals  in  the  decomposable fraction

are released when the organic matrix  is decomposed.

Table  3-10 lists metal concentrations taken  from refuse

sampled after segregatLorfor  use as  fuel in an incinerator-

electrical generator.  Some  of  the  combustibles are

completely resistant  to  microbial  attack  (certain plastics)

and others are only very slowly decomposed  (certain

plastic and rubber  types).   Therefore, metal concentra-

tions may be higher in Table 3-10 representing total

combustion than they  would be for  a biochemical decomposition

which would be incomplete.

Iron and manganese  are typically found  in leachate in

concentrations exceeding those  of  normal ground water.^^10)?

The anaerobic percolate  water can  reduce these metals to

lower valence states  which are  more soluble. The iron and

manganese may be present as  part of the refuse material, or

may be part of the  clay  or hydrous  oxide component in soil


Sulfur under aerobic  conditions is  oxidized  to the sulfate

ion.  Under anaerobic conditions,  it  is soluble as sulfide,

                                 REFUSE 8)
   Major elements
Typical value,
weight percent
weight percent
Iron (°)
Minor and trace
Copper * '

0.4 - 1.6
.23 -1.0
.3- 1.5
.05- .65
.05 -. 77
.07 -.7
.03-. 20
1.0 -.10
.1 -.3
.07-. 50
.04-. 84

6 -44
7 -70
3 -68
      Present also in the metallic state

or may occur  as  hydrogen sulfide  gas  (H2s) which has a
rotten egg  odor.   Sulfate has  been  reported  in leachate9*
and sulfide is probably  present in  some  leachates, but its
detection presents analytical  problems.  Moreover, many
metals form insoluble  sulfide  salts which  remove sulfide
from solution.

Phosphorus  is released by decomposition  of organic matter.
At the usual  pH  range  of leachate,  the H PQ^ and HPO^2 ions
are predominant.   As discussed below, soils  have a high
capacity for  phosphate attenuation, whereas  the refuse
material does not.  The  clays  and hydrous  oxides responsible
for attenuation  comprise only  a small fraction of the landfill
mass.  Phosphate can be  and  frequently is  produced in
substantial amounts in leachate.  Fungaroli  reported a
maximum of  130 ppm in  leachate from an experimental lysimeter.
His reported  concentration is  about as high  as has been reported,
but several others have  reached several  tens of ppm.12^
Effluents containing phosphate concentrations of this order of
magnitude discharged into surface water  would be expected to
produce a rather severe  eutrophication in  the receiving waters.
Were leachate to enter ground  water directly, it would almost
certainly contribute more phosphate than would percolate which
has passed  through soil  and  an unsaturated zone.

Water quality parameters which do not measure individual

chemical species include biochemical oxygen demand  (BOD),

chemical oxygen demand  (COD), total organic carbon  (TOC),

color, conductance, and turbidity.  The refuse zone provides

little, if any, attenuation of these characteristics;

instead, it usually increases them.  Bacteriological

investigations of leachate are in progress at the

University of Illinois and in the EPA.  Fecal coliform

and fecal streptococci have been observed in leachate,

and poliovirus was reported in leachate from a simulated

landfill.12^ The recent trend to use of disposable

diapers has increased the source of enteric bacteria in

solid waste.  Another source in some areas is septage which

may be disposed of on landfills with little or no treat-

ment. 9) Sewage sludges from municipal waste-water treat-

ment plants are frequently dried on sand beds and dumped in

landfills also used for other municipal refuse.

Movement of bacteria and viruses within the landfill and

through the unsaturated zone is dependent upon the

porosity of refuse and underlying geologic formations.

Refuse may offer many paths through which water can travel

relatively unimpeded.  If course sand and gravel or

fractured rock underlie the refuse, percolating water may

carry microorganisms with little or no attenuation except

for natural die off.  These conditions, judging from

locations which have been studied, are the exception rather


 than the rule.


 As  used herein,  the unsaturated zone is defined  as  the  area

 in  soil or sediments between the bottom of the landfill

 deposits and the water table.  The distance can  vary between

 zero (refuse contacting ground water)  to several hundred

 feet.   This zone is below what is usually considered

 "topsoil"  or the weathered,  organic-matter-rich  upper horizons

 of  most soils.   At most landfill sites,  topsoil  has been

 removed,  and sometimes much  subsoil also,  prior  to  deposition

 of  refuse.   The  porous materials comprising the  subsoil are

 likely  to  be low in organic  matter,  have a sparse microbial

 population,  and  may vary in  permeability over a  wide range.

 For  purposes of  discussion,  we will consider the unsaturated

 zone to be  20 to 200 feet thick.   This  range allows

 percolating water an opportunity to react chemically with its

 environment before reaching  ground water.   Percolating  water

 has  four options in passing  through the  unsaturated zone.  It

 can move virtually unchanged,  can show  a net gain of solute,

 show a  net  loss  of solute, or keep the  same  total ionic

 concentration with a net exchange of ions.   Since few soils or

 sediments are chemically inert,  changes  in  transported  solute

are to  be expected.

Chemical activity in the unsaturated zone is primarily

located at the surfaces of clay minerals and hydrous oxide

coatings.  Silts exhibit a small amount of chemical activity,

and limited microbial activity may take place either from

the indigenous population or that transported from refuse.

Clay minerals which occur in soils and sediments are small

aluminosilicate crystals possessing a large specific surface

area.  The crystal structure is such that clay particles

have a plate-like shape.  Particle sizes fall in the range

of true  colloidal particles,<2 urn.  The clay colloids carry

a net-negative surface  charge which results from internal

atomic substitution and ionization of surface hydroxyl  (OH)

groups.   The  negative  charge attracts cations from solution

and  they are  adsorbed  at the clay surface by weak  chemical

and  electrostatic  (van der  Waals) forces.   Cations can

exchange on  the  clays  and the  cation  exchange capacity  (CEC)

varies with  clay type.   The clay  types  in  order of CEC  are

accomplished on an equivalent charge basis, e.g.
displaces 2 Na+.  Ions of higher charge usually displace
those of lower charge in cation exchange reactions.

Cations will be removed from solution until either the
cation exchange capacity is reached, or the limit of
displacement reactions is reached.  The limit of CEC can
range from nearly zero to probably not more than 60
milliequivalents per 100 g soil.  Solution concentrations,
pK, and percolation rate affect the reactions quantitatively.
Thus, no quantitative predictions about attenuation can be
made without knowledge of specific site characteristics.  It
should be noted that adsorption is not a permanent fixation.
Cations may be desorbed with changes in solution composition,
pH, or oxidation-reduction  (redox) potential.

Divalent and trivalent cations  include most of the heavy
metals.  These are held more strongly than sodium, potassium,
or ammonium on the cation exchange complex.  Griffin and
Shimp measured the attenuation  by clay minerals of several
components of leachate.  ' They  rated attenuation as follows:
          High  Hg,  Pb,   Zn,   Cd
          Moderate Si,   Mg,  K,  NH4
          Low  Na,   Cl
          None  Ca,   Fe,   Mn

The rating "none" is believed to be caused by desorption of

calcium from clay exchange sites and dissolution of iron

and manganese in clay crystals by leachate.  Al, Cu, Ni,

Cr, As, S, and P04 were too low in concentration to be


Another source of cation adsorption and exchange is the

coating of iron and manganese hydrous oxides frequently

found on soil and sediment particles.14^ These coatings

exist in amorphous and microcrystalline forms with specific

surface areas of as much as 300 sq m/g.  Cations adsorbed on

the surfaces of newly formed hydrous oxides may, with time,

be incorporated  in their crystal structure.  Cations thus

incorporated are fixed, and no  longer exchangeable.

Surface charges  on hydrous oxides  are produced by  oxygen

and hydroxyl groups.  The surface  charge  is  dependent on pH

and redox  conditions.  Therefore,  the CEC exhibited by

hydrous oxides is pH  and redox  dependent.  The  CEC of

hydrous oxides approximates  that of  illitic  clays  (10-40 meq/

100 g).   Because hydrous oxides are  not a discrete fraction  of

soil  as clays  are,  CEC  calculations  come from laboratory


Heavy metals  are prone  to  sorption on hydrous oxide coatings

in soil.   The  hydrous oxides are frequently  cited as so

limiting metal  solubility  that  agricultural deficiences

of copper,  zinc,  and  cobalt  occur.     Attenuation of heavy

metals present  in leachate is desired.  In locations

virtually free  of clay minerals, these coatings may be

present on  sand grains giving the sandy formation some

ability to  attenuate  metallic ions.

Adsorption  is only one mechanism for removing dissolved ions

from solution.  Changes  in the  geochemical environment can

also affect solution  equilibria.  A transition from

reducing conditions in the landfill to oxidizing conditions

in the unsaturated zone  can  reduce the concentration of some

redox-sensitive species  in solution and change the chemical

form of others.   Iron and  manganese will oxidize and

precipitate from  solution, for  example.  If porosity will allow

bacterial movement, biochemical reactions involving leachate

constituents can  proceed.  Sulfide and ammonium can be oxidized

to sulfate  and  nitrate.  Dissolved organic matter measured in

terms of BOD and  COD  can be  reduced through microbial

decomposition.  Some  nutrient elements in the course of these

reactions will  be incorporated  in bacterial tissue and thereby

removed from solution until  the bacterial cells die off.

Conversion  of ammonium to  nitrate changes nitrogen from a subject

to attenuation  to a form which  is not.  Sulfide to sulfate

oxidation is not expected to be as significant.  Sulfide can
form insoluble precipitates with many of the heavy metals.
For this reason, it may not be present in more than trace
amounts in leachate.  Microorganisms may also attack the
organic ligands associated with chelated and complexed metals.
Decomposition or absorption by microorganisms would remove
the metals from leachate.

Phosphate reacts with a variety of soil components forming
insoluble products.  Calcium and phosphate react in
solution to form hydroxyapatite [Ca5OH(P04)3"J   the least
soluble phosphate compound known.  Iron, aluminum, and
manganese can also form virtually insoluble precipitates with
phosphate.  These reactions lead to a strong attenuation of
phosphate when these metal ions are present in the unsaturated

B&uwer  reports that in the Flushing Meadows high-volume
waste water recharge project, large amounts of phosphate have
been fixed in the unsaturated zone by chemical precipitation.  '
Phosphate fixed in this way amounts to about 43,000 Ib/acre
(48,000 kg/ha) calculated as phosphorus, and it has enriched
the unsaturated zone several tens of feet below the basin
surface.  This illustrates the potential for attenuation of
chemical reactions as well as the more often considered colloid

 surface reactions.

 Although phosphate  ions are negatively  charged,  they  interact

 with  clays  and hydrous oxides forming insoluble  complexes.

 These reactions may occur in either soils  or  subsoils.  The

 phosphate complexes are so insoluble that  phosphate added in

 fertilizer  must be  added in excess  to compensate for  fixation.

 The presence  of clay or hydrous  oxides  in  formations  beneath

 landfills is  valuable not only from the point of view of CEC,

 but also the  fixation capacity for  phosphate.

 Carbonate also reacts with calcium,  magnesium, and some

 heavy metals  forming relatively  insoluble  compounds.  The

 solubilities  vary according to metal species  and pH as  shown

 in Table _^rll_.  Calcareous deposits in the unsaturated zone

 can be valuable in  attenuating phosphate and  heavy metals from

 leachate.   Because  carbonate neutralizes acids,  BOD and COD

 present as  organic  acid may also be  reduced.  Some organic acids

 form  insoluble salts with calcium,  and  organic bases  are less

 soluble in  alkaline solutions.   Carbonate  induced alkalinity

may change  solubilities of heavy-metal  chelates  and lead to

 deposition  of heavy metals.

 Redox potential considerations are  particularly  important in

 the unsaturated zone.   Because of this,  a  brief  discussion of


                       (mg/l) 16)

the concept of oxidation and reduction in water systems is

included.  Reduction is the gain of electrons by a chemical

species; oxidation is the  loss of electrons.  Iron

chemistry illustrates a common water component which is

sensitive to  redox conditions.  It is reduced as follows:

              Fe+3  (slightly soluble) +e~	> F^+2

                    (more soluble)                   (?)

              Fe+2 +  2e   	> Fe°  (metallic)       (8)

The oxidation state  of  iron or other major redox sensitive

species in water in  combination with the  percentage

saturation of dissolved oxygen  determines the  redox potential

of water.

Redox potential in water is measured electrochemically with

gold  or platinum electrodes and a pH/millivolt meter.   The

voltage reading obtained for redox potential is termed Eh.

Eh values range from over one volt for highly oxidized
systems to negative  voltage values for reduced systems.

Ground water frequently exists at a low Eh potential in

comparison to surface water.  The low Eh governs solubilities

 (iron, manganese), chemical species actually in solution

 (Fe+3, FeOH+2, FeO42), and governs certain geochemical

 transformations  (nitrification, sulfate  reduction).  Because

 of these geochemical controls, it is important to determine

 Eh when geochemical interpretations must be made.


A comment on Eh determination is called for because, although

useful, this measurement on ground water is difficult to make,

Any exposure of the water to the atmosphere will instant-

aneously change the Eh value.  This necessitates a closed

system from the pump to sealed electrode holder.  Water must

also be pumped until the Eh stabilizes, which may require as

much as several hours pumping time depending upon rate of

discharge and subterranean conditions.  An Eh determination

made without proper care can be worse than useless because

it will indicate conditions which, in fact, do not exist.

The unsaturated zone is influenced by the percolation of

leachate into it and simultaneously influences the leachate.

Water of low Eh first infiltrating into the unsaturated zone

of high Eh will become more oxidized while simultaneously

reducing substances in the unsaturated zone.  A continued

percolation of reduced water may con«/erc what had been an

oxidized system into a reduced one.  Or the percolate may

become oxidized if that capacity in the unsaturated  zone is

greater.  The degree of influence of reduced leachate on the

oxidized unsaturated zone and vice versa depends upon the .

reserves of material capable of oxidizing or reducing in the

unsaturated zone and leachate.  The greater the distance

leachate travels between refuse and ground water, the better

the chance that the entire path through the unsaturated  zone


will not become reduced.  Raising the Eh of leachate will

tend to attenuate some components in solution at the point

of exit of the refuse zone.

Leachate reaching ground water may as a result of the

geochemical conditions en route be depleted in. some

constituents and enriched in others as dictated by the

composition of the  unsaturated zone and its overall affect

on Eh and pH.  Distance of  travel, speed of percolation,

flow-nonflow cycles, and leachate temperature are all

parameters controlling leachate quality.


Concepts useful for describing surface water pollution are

generally not valid for ground water.  Ground water move-

ment is described by Darcy's Law which states that velocity

is directly proportional to the permeability of the aquifer

and the hydraulic gradient, and inversely  proportional to the

porosity.  Ground-water flow velocities vary over a wide range,

with 5 ft/yr to 5 ft/day being typical.  Highly permeable

outwash glacial deposits,  fractured basalts and granites,

and cavernous  limestone aquifers allow very much higher


The generally  slow  velocity of ground water results  in

laminar flow which  exhibits different characteristics of


 mixing than does the turbulent flow usually associated with
 surface streams.  A water of different chemical composition
 from ground water which is injected or percolated into
 ground water tends to maintain its integrity and is not
 diluted with the entire body of ground water.   Instead, it
 moves with the ground-water flow as a plume undergoing
 minimal mixing.  The plume shape is determined by the
 physical characteristics of the aquifer.   Porous media give
 somewhat different shaped plumes from fractured rock or
 cavernous  limestone.   Figures	,	,	,	,3^^ Q^^, „
 illustrate the paths  of ground-water movement  in various
 hydrologic regimes.   It is obvious  that plumes of leachate-
 enriched ground water in these  environments would assume
 different  shapes.

 Other hydrologic conditions  further influence  plume  shape.
 Hydraulic  gradients going  in  more than one direction,  such  as
 occur if ground-water mounding occurs beneath  a  landfill, will
 spread leachate  laterally, creating a plume wider  than  the
 areal extent of  the landfill.  A vertical gradient is  less
 often encountered, but should it be present, leachate would
 follow ground-water flow downward as well as horizontally.
Leachate may exert an influence on  the shape of the plume
of contamination it produces.  Almost universally, leachate

temperature will be above ambient.  It may be as much as 50° F

above the ambient ground-water temperature.  Leachate may also

have a dissolved solid concentration sufficiently high to

increase its density over that of ground water.  These

combined physical characteristics may significantly affect

the way in which leachate interacts with ambient ground water.

For example, one study in a highly permeable aquifer showed

that leachate sinks directly  to  the bottom of the aquifer

beneath the landfill.9*  No natural vertical gradient was

measured where  this phenomenon occurred.

Differential attenuation is defined as a reduction in

concentration of a dissolved  constituent with distance along

the direction of water  flow which  is disproportional to

changes in  concentration of other  constituents.  Differential

attenuation may result  from chemical reactions  which remove

the constituent from solution or from  self destruction.

Apparent  attenuation occurs  from dilution  by mixing with water

of  lower  constituent concentration.

Dilution  may  take  place in ground water  in two  ways.   One  is

hydrodynamic  dispersion,  and the other is  molecular  diffusion.

Microscopic dispersion is  mixing caused  by the tortuous  flow

of  water  around individual grains and through  pores  of various

sizes  in  a porous  aquifer.   Macroscopic dispersion is  mixing as

water  flows in and around heterogeneous geologic formations.


Molecular diffusion operates on a much more restricted scale.

It is the diffusion of solute across a concentration gradient

from stronger to weaker.  Diffusion is seldom possible to

measure in the field.  There are mathematical formulas which

describe dispersion.

In order to calculate a dispersion coefficient, an intensive

investigation of the site over a period of time is necessary.

Hydraulic gradient, porosity, concentration gradients in the

plume, temperature, and measurement of solute movement are

all factors entering into the formula.  The time during which

the plume has been in existence is also important.  The extent

of the dispersion is a function of time.  Forecasting a

future extent of the plume may require a mathematical modeling

program in which dispersion is only one of the characteristics

of the system.

Chemical interactions provide the greatest amount of

differential attenuation in the aquifer zone.  Hydrous oxides

of iron, aluminum, and manganese or clay minerals present in

aquifers attenuate cations in the same way that they do in

soils or the unsaturated zone.  Because hydrous oxide and clay

colloids are in constant contact with water in the aquifer, it

can be assumed that the exchange sites are saturated and

essentially in equilibrium with the ambient ground water.

Leachate-enriched ground water when contacting these colloids

will initiate cation exchange which results in desorption of


cations which  are  less  strongly held  than those replacing them.

In this way, hydrogen,  sodium, calcium, and magnesium may be

released into  the  aqueous  phase by exchange with heavy metals

and other cations  in  leachate.  High  hardness values associated

with leachate  plumes  may be  due in part to this ion exchange


Chemical precipitation  in  the aquifer is possible if the

natural ground-water  composition  includes ions which form

insoluble compounds with constituents in leachate.  A.I

example would  be formation of hydroxyapctite with leachate

phosphate and  calcium in ground water.  Other precipitation

reactions may  occur  if  geochemical conditions are encountered

in the aquifer which  lead  to changes  in redox potential or pH.

Buffering reactions may change concentrations of bicarbonate,

carbonate, ammonium,  and sulfur  (I^S,  HS~).  Reserves of

hydrogen (acid) or hydroxyl  (base) ions may be present in

ground water if it has  unusually  high or low pH.  Clays and

hydrous oxides also are capable of releasing hydrogen ions from

exchange sites for reaction  with  dissolved species.

The third means of attenuation in aquifers is that termed decay.

Oxidation of organic  compounds produces carbon dioxide and water

and eliminates the compounds.  Radioactive species undergo

radioactive decay  to  stable  daughter  products.  Some elements


 decay  in terms  of seconds  and  others  lose  half of  their
 activity in  periods  measured in  thousands  of  years.   Radio-
 active materials  should not be present  in  municipal  landfill
 leachate.  Micro-organisms carried  into the aquifer  zone  are
 deprived of  a good nutrient supply  and  are subjected to a
 generally cooler  temperature.  This results in a lowering
 of biochemical  activity, frequently to  the point of  cessation.
 Bacteria can quickly adapt to  hostile conditions by
 encysting and ceasing activity.  They may  remain inactive,
 but viable in this form from days to weeks.   Bacterial cells
 are attracted to  inorganic colloid  surfaces and are  also
 subjected to physical filtration.   These phenomena coupled
 with natural die  off,  tend to  reduce bacterial numbers rather

 There  are  two additional complications  in  the interpretation
 of ground-water quality  in leachate plumes.   One is  the
 variation  in leachate  concentration with time, and the other
 is the discontinuous  recharge  of leachate  which occurs in most
 geographical regions.

 Leachate production begins as  soon  as deposited refuse is
wetted to  field capacity.  The lag  time depends upon  local
 climatic conditions and rate of refuse deposition.   In an
active landfill, older organic matter is stabilizing while

  simultaneously new organic matter is beginning to ferment
  and produce stronger leachate.   The net effect is an
  increasing leachate concentration from a given area,  or an
  increasing areal contamination,  or both as  long as  the
  landfill is active.

  Leachate produced at the initiation of percolation  through
  the  landfill is  less concentrated than that produced  after
  several  years' refuse accumulation.   This leachate will be
  found at the distal  end  of  the plume  of leachate-contaminated
 ground water.  The closer the sampling site to  the la-idfill,
 the more  concentrated should be the contaminated ground water.
 An increasingly concentrated leachate  source in addition to
 the factors of dilution  and attenuation must be considered
 in interpreting the results of sampling the plume.  An
 erroneously high value for attenuation or dilution may be
 given if the variation in source strength is ignored.

 The intermittent recharge occurring from most landfills  also
 complicates interpretation of leachate-plume configuration.
 During summer months when evaporation frequently exceeds rain-
 fall, little or no leachate  may  be produced.   Ground water,
 however,  moves under the  landfill  at a relatively steady rate.
 Thus, there will  be variations in  the  volume  and strength of
 leachate  reaching  ground  water during  the course of  time.
These variations will show in the  leachate plume as  variations
in total  solute concentration.  A  sample taken  from  the plume
at any given  time  may represent a  "high"  or  "low"  in the

 intermittent  recharge pattern.  One way to visualize this

 phenomenon would be  to watch the response of a conductivity

 probe  in  a well screen over time.  As leachate-enriched

 ground water  moves past the point, conductivity will vary

 with changes  in dissolved solids concentration.  The

 variations may be noticeable only in time spans of weeks to

 months.   Again, this complicates efforts to calculate values

 for dispersivity or  dilution because concentrations vary from

 factors other than aquifer characteristics.

 A generalized summary of the susceptibility of leachate

 constituents  is provided in Table 3-12.  The mechanism of

 attenuation which affects each constituent is listed for the

 zones  through which  leachate may pass.  When data are

 summarized in this fashion, only the principal mechanisms can

 be cited.  For example, no attenuation is listed for all of

 the constituents in  the refuse zone.  This is not really true

 as the previous discussion points out.  However, quantification

 is impossible, and there is a net output of most of the

 constituents.  Sulfate, nitrate, and ammonium are given

biochemical conversion alternatives.  These ions are subject

 to oxidation and reduction reactions which may convert or

eliminate them.   Heavy metals are also prone to one or more

of the attenuation mechanisms,  and may not be universally present

in leachage.   Biochemical reactions were not listed for the


Table 3-12
Attenuated Constituent
Heavy metal onions
(Cr7V. Se,B,As)
Heavy metal cations
(Pb, Cu, Ni, Z n7 Cd, Fe, Mn, Hg)
Organic nitrogen
Volatile Acids
Refuse Zone


Un saturated Zone




  0 = no attenuation
  A = adsorption
  B = biochemical degradation on conversion
  C = chemical precipitation

aquifer zone because biological activity is inhibited.  In

places, biological activity may be significant in the

aquifer, but the amount and type cannot be predicted.

                  REFERENCES CITED

1.    Merz, R. C., and R. Stone. 1968.  Quantitative study
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