SW-91d
             Prepublication issue for EPA libraries
            and State Sot-id Waste Management Agencies
                 DEMONSTRATION  OF A LEACHATE
                        TREATMENT PLANT
           This interim report (SW-91d) describes work
     performed for the Federal solid waste management program
              under demonstration grant no S-8OS926
          and is reproduced as received from the grantee
                Copies will be  available from
        the National  Technical Information Service
                U.  S.  Department of Commerce
                 Springfield, Virginia  22161
             U.S. ENVIRONMENTAL  PROTECTION AGENCY

                             1977

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This report has been reviewed by the U.S. Environmental Protection
Agency and approved for publication.  Its publication does not signify
that the contents necessarily reflect the views and policies of the
U.S. Environmental Protection Agency, nor does mention of commercial
products constitute endorsement or recommendation for use by the U.S.
Government.

An environmental protection publication (SW-91d) in the solid waste
management series.
                        EEVIEO'.

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                         TABLE  OF  CONTENTS

                                                              PAGE

      Summary and Conclusions                                    1

  I.   Introduct ion                                              5

 II.   Overview of Leachate Treatment Options                    7
           Leachate Composition                                 7
           Leachate Treatment                                   '^
           Summary                                             19

Ml.   Leachate Treatment System                                22
           Design Overview                                     26
                Design Flow                                    26
                Design Leachate Characteristics                26
                Design Concept                                  28
                Leachate Collection  System                      28
           Chemical/Physical  Section                           28
                Chemical Precipitation                         28
                Air Stripping of Ammonia                       30
                Neutralization  and Nutrient Supplementation    30
           Biological  Treatment Section                        30

 IV.   Materials  and Methods                                    32
           Experimental Systems                                  32
                System  1  - Chemical/Physical  Followed by      32
                            Biological  Treatment
                System  2  - Chemical/Physical  Treatment        32
                System  3  ~ Biological  Followed by Chemical/   32
                            Physical  Treatment
                System  ^  - Biological  Treatment                32
           Process Monitoring                                   32
           Bench-Scale Testing                                  34
           Statistical  Tests                                    35

  V.   Results and Discussion                                    36
           Preliminary Results                                  36
                Raw Leachate Quality                           36
                Lime Dosage                                    36
                Sulfuric Acid Docage                           39
                Phosphoric Acid Dosage                          39
           System #1                                            39
                Operational Comments                            ^2
                Cost Data                                       ^3
           System #2                                           ^3
                Operational Comments                            ^"
                Cost Data                                       ^
                             iii

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                         TABLE OF CONTENTS (Cont.)
               Systems 3 and 4                               50
               System  5                                     52
  VI.  Progress Evaluation                                   56

 VII.  References                                            62

VIII.  Appendix - Leachate Treatment Plant Operation
                  and Maintenance Routine                    64
                                   iv

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                            LIST OF  FIGURES
                                                            Page

Figure - 1      Reduction  of  COD  during  Aerobic Treatment     15

       - 2      Changes  in TDS  during Aerobic Treatment       16

       - 3      Location of leechate  Treatment Plant          24

       - k      Schematic  of  Leachate Treatment p'ant         29

       - 5      Influent COD  Date                            38

       - 6      Work  Schedule                                59

       - 7      Work  Accomplished during  First Year           60

       - 8      Proposed Work for Second  Year                 61
                                  v

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                             LIST OF TABLES
                                                             Page

Table - I      Summary of System 1  Operating Data                /»

      - 2      The Strength of Raw Leachates                     9

      - 3      Effect of Solid Waste Disposal  on Groundwater    10
              Qua!ity

      - k      Effect of Landfill  Depth on Leachate Composition 11

      - 5      Theoretical  Removal  of Heavy Metals during       18
              Lime  Precipitation

      - 6      Leachate Treatability                            20

      - 7      Precipitation Data,  Trenton, New Jersey          23

      - 8      Effluent Criteria                                25

      - 9      Design Leachate Characteristics                  27

      - 10    Routine Laboratory  Analysis                      33

      - 11    GROWS  Landfill  Leachate Characteristics          37

      - 12    System 1 Performance                             k]

      - 13    System 1 Costs                                    kk
                                                         i
      - \k    Summary of System 2  Results                      46

      - 15    Effects of Chemical/Physical Treatment           47

      - 16    System 2 Costs                                    kS

      - 17    Phosphorus Limitation Experiments                51

      - 18    System 5 Results                                 53
                                  VI

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             DEMONSTRATION OF A LEACHATE TREATMENT PLANT

             R.L. Sterner, Ph.D., P.E., J.E. Keenan, Ph.D.,
                      A.A. Fungaroli, Ph.D., P.E.

                       Summary and  Conclusions

     The results of the operation of a full-scale sanitary  landfill
leachate treatment plant are reported.  The plant is designed to pro-
vide a variety of chemical/physical and biological treatment sequence
options.  The chemical/physical units include lime precipitation, sedi-
mentation, air stripping, neutralization and nt-trie^t supplementation.
These treatment processes are designed to  reuove heavy metals, ammonia
and organic materials, and to encourage subsequent biological treatment
by reducing the pH and adding the nutrient phosphorus.  The biological
treatment process is activated sludge.  The demonstration leachate treat-
ment plant is designed to provide operational flexibility in that the
flow can be directed through the various unit processes ere* operations
in any sequence.

     The purpose of this project is to demonstrate the efficiency of a
number of treatment sequences.  Specifically, five modes of operation
have been defined and are being investigated.  System 1 consists of
chemical/physical treatment followed by activated sludge: System 2,
chemica1/physical treatment only; System 3, biological treatment fol-
lowed by chemical/physical; System k, biological treatment only; System
5, bench-scale studies, including activated carbon adsorption treatment.

     Data have been collected which can be us^d to characterize the quality
of raw leachate generated in an operating sanitary landfill.  The•.-«? data
show that the leachate from this sanitary  landfill source is high in or-
ganic matter (average COD/1 iter of 11,210 mg.,  average BOD^/liter of
mg) and nitrogen (average NH/,4" = N/liter of 1,503 mg).  The raw leachate
heavy metals concentrations are somewhat lower than expected, possibly
reflecting the relatively high pH of the leachate.  (Note that all  data
have been collected with non-filtered samples.)

     High concentrations of ammonia in the raw leachate exceed the
plant's effluent criteria and are sufficient to inhibit the growth of
the activated sludge microorganisms.  For this  reason the original  plant
design htis been augmented with an ammonia air-stripping lagoon.

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     System 5 studies have been conducted for a number of purposes.
Bench-scale tests have provided optimal operating data for chemical/
physical units.  In particular, System 5 has provided data for the
development of lime, su!furic aclc' and phosphoric acid dosages.

     Activated carbon adsorption has been evaluated as a treatment
method for raw leachate.  For raw leachate, carbon adsorption did not
prove to be an effective treatment procedure.  The inability to use car-
bon adsorption is the result of high suspended solids loading causing
increased pore plugging and the wide range of flow variability.

     Systems 3 and  4,  those in which raw leachate is  influent to the
biological units, have received considerable operating attention.  The
preliminary results indicate uSat the raw leachate is not directly
treatable by biological means.  The operating experience s'"ows that
an activated sludge can not be developed on raw leachate.  The failure
to develop activated sluc'ge is attributed to t^e nutrient imbalance
caused by a lack of phosphorus and to an "r!->ib'•; ton caused by toxic
levels of ammonia.

     Systems 1  and  2 are those in which the raw leachate  is  treated
first by chemical and physical means.  The results of these systems are
most promising.  Lime precipitation followed by sedimentation has been
successful in removing the heavy metals and a portion of the organic
matter.  Specifically, this sequence has removed about one-third of the
dissolved solids and nitrogen; one-half of the organic matter; three-
quarters cf the suspended solids; and ninety percent of the phosphates.
The sequence has been successful in removing the heavy metals including
one-third of the cadmium; one-half of the chromium and nickel; two-
thirds of the lead and mercury; three-quarters of the copper; and over
ninety percent of the iron and zinc.

     An air stripping lagoon is included in the chemical/physical
treatment sequence because of the excessive ammonia levels in the raw
leachate.  During the lime precipitatlon/clarification/atr stripping
mode of operation,  the following removal efficiencies have been achieved:
56-57 percent BOD and COD; approximately 60 percent of the ammonia-N and
total Kjeldahl-N; approximately 67 percent of the suspended solids; 50-
65 percent of cadmium, nickel and mercury; 70-80 percent of chromium
and copper; approximately 88 percent of lead; approximately 95 percent
of zinc; and approximately 99 percent of iron.

     The lagoon has a detention time of ten days, thereby providing an
equalizing effect.   That is, the effect of the lagoon is to dampen the
peaks and to minimize shock loadings on subsequent treatment units.  For
example, during the period in which the lagoon was included in the
treatment sequence, the 99 percent confidence interval for ammonia in
the raw  leachate was 241-1285 mg/liter; while during the same period
the lagoon effluent 99 percent confidence limit was 210-425 mg/liter.
Thus, the equalization effect is significantly beneficial in terms of
lessening shock loadings.

                                   -2-

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     System 1  has provided the best degree of treatment to date.  This
sequence consists of lime precipitation/clarification/air stripping/
neutralization/phosphorus addition/activated sludge.  !n this opera-
tional configuration, excellent removal efficiencies ha^e been observed
following the adaptation of the activated sludge to the waste.  In all
cases except NH^-N, these effluent concentrations comply with the
effluent criteria developed by the Pennsylvania Department of Environ-
mental Resources and the Delaware River Basin Commission for discharge
to the Delaware River.   A summary of the data is presented in Table 1.
                                  -3-

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                          TABLE 1




             SUMMARY OF SYSTEM 1 OPERATION DATA

Parameter
Ammonia-N
BOD5
Cadmium
Chromium
COD
Copper
1 ron
Lead
Mercury
Nickel
Zinc
Raw
Leaciiate
mg/1
510
4993
0.049
0.105
9689
0.313
205
0.545
0.015
0.52
3.64
Final
Effluent
mg/1
46.5
60.5
0.014
0.075
576
0.078
0.96
0.12
0.004
0.27
0.44
Percent
Remova 1
?0.9
98.8
71.4
28.6
94.1
75.1
99.5
78.0
73-3
48.1
87-9
Discharge
Standard
mg/1
35
100
0.02
0.1
*
0.2
7.0
0.1
/ .01
5V
0.6

discharge standard for this parameter.
                               -4-

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             DEMONSTRATION OF A LEACHATE TREATMENT PLANT


           R.L. Steiner, J.D. Keenan, and A.A. Fungaroli



                          1.  INTRODUCTION

     The potential for water pollution from sanitary landfill sites has
become recognized in recent years.   A number of st'.'dTes^~^" have docu-
mented lie great pollutional strength of landf;", I  leachates.  The quali-
ty of this material  varies with  landfill age,  nature and  moisture con-
tent of the wastes disposed at  the  site, and hydrologic and soil factors.
In spite of this variability,  it  can be stated that, especially for
young landfills, the values of  the  critical  sanitary parameters of
leachate are at least an order  of magnitude greater than  for domestic
sewage.  The deleterious consequences following contamination of ground
and/or surface waters by leachate may be severe,  and it is for this
reason that leachate treatment  is receiving attention.

      Solid waste  consists of matter which can be decomposed  by  bacterial
or microbial action, as well as of materials which  are inert  to micro-
biological activity.  Some of the compounds, cellulose in particular,
are  resistant  to  biological breakdown, but with sufficient time decompo-
sition will occur.   Because of this resistivity and necessity to accli-
matize the biological system, the chemical characteristics of leachate
are  time/'-dependent.  To complicate treatment, as the paper decomposes,
some  of the  inorganic ions which are bound to the organic matrix are
released and can  be  removed by water percolating through the  landfill.
The actual mechanism of removal varies with the component but includes
solution as well as colloidal transport.

      The generation of leachate  In landfills is complicated and
cannot be generalized simply as surface water percolating through  the
sanitary landfill.  When refuse  is placed in the landfill, decomposition
begins to occur.  Some decomposition products may be water soluble where-
as the parent  products might not have been.  This is especially true of
cellulose.   in addition, the inorganic constituents also must be con-
sidered since  they vary with the state of decomposition.   The amount
of water percolating through a sanitary landfill  is the primary control
of leachate quality, but the chemical characteristics of the  leachate
are dependent  on other parameters,  including temperature, waste compo-
sition, moisture  content, time, mode of decomposition (aerobic, etc.)
and the amount of infiltration of rainfall at the landfill.
                                   -5-

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     Recent studies have shown that leachate is produced  in a sanitary
 landfill when the precipitation exceeds the net evapotranspiration of the;
 region.  Remson, Fungaroli, and Lawrence developed a model for predicting
 the movement of leachate through a sanitary landfill.   Further  results
 using this model have substantiated the validity of the approach and
 prediction of leachate generation patterns is reasonably accurate.

     Ground and surface waters can be protected if the landfill  is under-
 lain with an impervious membrane.  With proper design, leachate  is then
 directed toward collection points.  A waste such as this, wh;ch  's pro-
 perly considered an industrial waste, must be treated prior .o surface
 discharge.  The leachate treatment state-of-the-art is still embryonic,
 although a few small scale studies have been conducted.  These have de-
 monstrated that neither conventional chemical  treatment nor biological
 treatment can achieve the high degree of treatment efficiency expected
 today.  Consequently, although we know that the poT'Jt'on potential of
 sanitary landfill  leachate can be avoided by --perception using  imper-
 vious liners, we are not yet able to define the optimum sequence of unit
 operations and processes required ror adequate wastewater renovation.

     The U.S. Environmental  Protection Agency,  Office of  Solid Waste
Management Programs, has awarded  demonstration  grant  (S-803926)  to
 investigate the effectiveness  of  alternative treatment sequences as
employed at the full-scale  facility in Falls Township, Pennsylvania.
A 380 liter per minute (O.lAA  gpd) plant had been  constructed to treat
 leachate from the  GROWS (Geological  Reclamation Operations and Waste
 Systems, Inc.)  landfill.  This project has as  its  primary goal the
evaluation of the  technical  feasibility, operational  efficiency and
cost effectiveness  of four  alternative treatment sequences.   These
are: (l) chemical/physical  followed by biological; (2) chemical/physi-
 cal alone; (3)  biological  followed by chemical/physical;  and (k)  bio-
 logical  alone.   The chemical/physical  processing includes precipita-
 tion of heavy metals by lime addition, sedimentation,  air stripping
of ammonia and neutralization  using sulfuric and/or phosphoric acids.
 Biological treatment consists  of  conventional  activated sludge.   Addi-
 tional objectives  of the study are the bench-scale evaluation of
carbon adsorption  on both raw  and unit process  effluents;  and bench-
 scale testing to determine  chemical  dosage, sludge return rates,
aeration rates and  other plant operating criteria.
                              -6-

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             II.  OVERVIEW OF LEACHATE TREATMENT OPTIONS

     The purpose of this chapter is to review the  literature regarding
the composition of sanitary landfill leachates and their treatment.   !n
brief, the character and variability of the leachate dictates the types
of treatment systems which will be effective.  The contaminants of
greatest concern fall into several groups.  The first group 5s the or-
ganic chemicals, important primarily because they exert an oxygen demand
on receiving waters which may result in a depletion of dissolved oxygen
deleterious to aquatic life.  The second major group of contaminants
found in sanitary landfill ^eachates is comprised of the heavy metals.
As a group, these elements a-e of concern because they are toxic at
sufficiently high concentrations.  It is conventional practice to chem-
ically characterize wastewate, s such as leachate in tems of a number
of other parameters.  These are used ^or a variety of purposes including
design, operational  control, and evaluation ^r oo'lution potential.

                         LEACHAT1; COMPOSITION

     In 1932, one of the first studies indicating that the disposal of
solid waste could cause environmental pollution was reported by Calvert ,
who investigated the liquid waste from a garbage reduction plant in In-
dianapolis.  In this process the garbage was cooked and the grease re-
moved to produce fertilizer and animal  feed, and the liquid waste was
discharged into an impounding pit or lagoon.  An analysis of this liquid
is presented in Table 2,  Column 1.   Calvert analyzed the groundwater
from existing wells surrounding the lagoon and found that wells up to
500 feet downstream of the site showed a marked Increase in magnesium,
calcium, total  dissolved solids and carbon dioxide.

     Carpenter  and Setter , working at New York University in 19^0, con-
ducted one of the earliest studies concerned with landfill leachate.
Auger holes were drilled through an existing landfall of undetermined
age into the subsoil.  Twenty-eight samples of leachate which were col-
lected in the bore holes were analyzed cnernically.   The range of con-
centrations is  presented in Table 2,  Column 2.   These results showed
a wide variation of concentration over the site, thus indicating the
difference of filled materials at various locations, or the differences
in the age of the refuse at different points.  Analysis of groundwater
in the area was not  performed,  therefore the effect on the subsurface
environment v^as undefined.

     The first  comprehensive research study of sanitary landfills under
controlled conditions was conducted at the University of Southern Cali-
fornia^.  Test  bins, simulating landfill  conditions, were constructed.
Water was added to simulate the infi1tration of 1.12 m and leachate was
collected and analyzed.   Table 2 c,ives  the minimum and maximum (Column
3) values of the initial  (first *»5.9 liters of leachate per cu m of com-
pacted refuse)  leachate.   The most rapid removal (the highest concentra-
tions)  occurred with the first  232 liters per cu m of refuse.   Thus, it

                                 -7-

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was postulated that removal would continue for many years but at a very
slow rate, and it was considered unlikely that all the constituents
would ever be removed.

     The same study also examined a field site consisting of 2.4 m of
refuse and 0.61 m of cover material.  The refuse was in intermittent
contact with the groundwater, analysis of which showed increases in all
organic ions and a maximun biochemical oxygen demand of 125 mg/liter.
One conclusion of the study was that the dissolved inorganic ions en-
tering the groundwater through intermittent contact would decrease in
concentration as a result of dilution and adsorption and travel in the
direction of the groundwater movement.

     The other conclusions reached in this study are summarized as
follows:  (1) A landfill, if located so that  it is in inter-
mittent or continuous contact with ground water, w*'1 cause the ground
water in the immediate vicinity of the larcl'~iT  to become grossly
polluted and unfit for domestic or irrigational use; (2) dissolved
mineral  matter, entering ground water as a result of intermittent and
partial  contact of a landfill with the underlying ground water
will have its greatest travel in the direction of flow, undergo a ver-
tical  diffusion to a limited extent, and be subject to diction, the
result of which will be a minimizing of the effect of the entering
pollutant ions; (3) a landfill,  if located so that no portion
of it intercepts the ground water, will not cause impairment of the
ground water for either domestic or irrigational use; (4) rainfall  alone
(in the area of this study) will not penetrate a 2.3 m thick landfill
sufficiently to cause entry of leachate into the underlying ground water.


     Longwell^ stated in 1957 that an appreciable proportion of refuse
could be extracted by water to produce a leachate rich in organic matter,
inorganic salts (ions), and/bacteria.  The analysis of a surface leachate
obtained from an unnamed landfill is given in Table 2 (Column 4).

     In 1961 the British Ministry of Housing and Local Government con-
ducted extensive research on the placement of landfills above the ground-
water table  ( which they called "dry tipping"), and the placement of
landfills below the groundwater table (which they called "wet tipping")  .
In the "wet  tipped" experiment the refuse was completely submerged and
the horizontal groundwater flow rate was equivalent to 138 liters per sq
m per day.  The leachate quality is included in Table 2 (Column 5).
Analyses of  the groundwater before and after contact with the refuse
are given in Table 3-   These results show the considerable extent  of
groundwater quality degradation due to pollution by leachate.

     In 19C5 Qasinv studied the seepage waters from simulated landfills
at the University of West Virginia.  Three concrete cylinders 0.9 m in
diameter and 1.2, 2.4, and 3-7 m in height were filled with municipal

                                  -8-

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                              Table 3

      EFFECT OF SOLID WASTE DISPOSAL ON GROUNDWATER QUALITY
        GROUNDWATER QUALITY BEFORE AND AFTER INTRODUCTION
                  OF "WET TIPPED" LANDFILL -

Measured Quantity
Total solids (residue)
Chloride
Alkal inity, as CaCO,
Sulfate
Biochemical oxygen demand (BODr)
Organic nitrogen
r
Upstream
Landf i
450
30
180
120
0
0
oncentration (mg/l)
of Downstream of
11 Landfill
5,000
500
800
1,300
2,500
70
	 / 	
-MINISTRY OF HOUSING AND LOCAL GOVERNMENT.   Pollution  of Water by Tipped
 Refuse.  Her Majesty's Stationery  Office,  London.   1961.
                                -10-

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-11-

-------
refuse.  Approximately 102 cm of precipitation was artificially added
to the cylinders over a period of 6 months and leachate samples were
collected.  The maximum concentrations of certain organic and Inorganic •
components in the leachate from the three cylinders are presented in
Table 4.   Table k also presents the total  weight removed per
cubic meter from each depth of f'H by 102 on of simulated infiltration.

     A summary of results presented by Qasim demonstrates the effect of
depth on leachates generated by landfills.  Concentrations of various
pollutants were higher in leachates obtained from deeper fills.  Concen-
trations of various pollutants per unit depth of fill decrease with in-
creasing depths of refuse.  For an eoual  amount of influent, shallower
fills showed greater extraction rate per unit volume of fill than deeper
fills.  The bulk of the poPt'ion was attributed to initial leaching.
                          o
     Anderson and Dornbush  conducted an extensive investiqation of the
groundwater leaving a landf"1!  :n Brookings, South Dakota in
1967.  An abandoned gravel pit of 160 acres w.th its base well below the
water table was filled with municipal solid waste.  The purpose of the
investigation was to determine which chemical parameters were the most
reliable indicators of the influence of landfills on the groundwater.
Groundwater samples from 22 wells located over the site were analyzed
for chloride, total hardness, alkalinity,  sodium, pH, potassium, iron,
nitrate,  and specific conductance.  A considerable increase in all  con-
stituents measured was observed in three wells immediately downstream of
the fill  area.  Although the authors did not evaluate the potential  pollu-
tion of municipal refuse, they did report  an increase of up to 50 times
the chloride content of native waters in the groundwater affected by the
leachate.  The major conclusion of this investigation was that two of
the most important indicators of pollution from landfills are chlorides
and specific conductance or total dissolved solids.  Chloride ions are
easily detectable, not readily absorbed by soils, not affected by bio-
logical processes, and apparently an abundant product of leachates.

Disposal  sites in northern Illinois were investigated in 1970 by
Hughes, £t_aJ_-9  Leachate samples from three landfills of varying age
were obtained as near to the base of the refuse layer as oossible.   The
results of these analyses are presented in Table 2 (Columns 6-8)
Although no information is given in the study as to the composition  of
the solid waste in each fill, and the analyses were performed on only
one sample, the results do show a decreasing trend with time.  However,
it was noted that refuse more than 15 years of age can still have a
high total dissolved solids content - indicating that the stabilization
of landfills is a long process.

     The laboratory simulated landfill or lysimeter study conducted at
Drexel University from 1967 to 1972 is the only study reported that was
conducted under completely controlled laboratory conditions.  It was
also the only study reported in which the. environmental conditions com-
pletely simulate the existing clinatic conditions of a region, in this


                              -12-

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case, southeastern Pennsylvania.  The  refuse was placed at as  received
moisture content and allowed  to  reach  field capacity naturally  through
the addition of amounts of distilled water equal to the precipitation
of the area minus the evapotransplration.  This  infiltration was added
on a weekly basis and varied  from a rate of 8.9  cm per month during  the
wet periods to zero during the dry or  summer periods.  Approximately
one year was required for the refuse to reach field capacity,  but small
quantities of leachate were generated  before field capacity was reached.
The maximum concentrations obtained in the first year are given in Table
2, column 910.

     It was concluded that this  initial leachate production came from
the following sources:  (l) From the refuse.  Most of the initially
generated leachate is squeezed' from the organic  components of the refuse
by the compaction and placement  procedure.  (2)  From channeling.  Some
of the water added at the top of the lysimeter may Hpd a direct route
through the refuse to the co' lection trough, c'-je to any inhomogenei ties
in the refuse.  (3)  From an  advanced wetting front.  The wetting front
in the refuse probably moves  as  a broad band rather than as a single
line interface.  As a result, substantial increases in leachate will
occur before the entire system is at field capacity.  (A)  From the  main
wetting front.  This is the leachate which is produced w^cr? the system
reaches field capacity.  At this time, the input water and the output
leachate quantities become approximately equal.

     Other studies have mentioned the  leachate problem of refuse dis-
posal in papers dealing with  other aspects of the solid waste problem.
Leo Weaver has stated that municipal refuse can generate leachates high
in organic pollutants.'1  Data from this study are included in Table 2
(column 10).

     Engineering Science in a study conducted in 196? in southern Cali-
fornia concluded that groundw^ter pollution, which may arise from re-
fuse leachate reaching a water source, will be shown largely as an in-
crease in total dissolved solids and specif
-------
     Table 2 (columns !l-'3) presents a summary of values of raw
leachate composition as compiled by Chi an and DeWalle.'"  The ranges
represent leachates examined by a number of investigators (Range 1-
Column 11) and a variety of leachates studies at the University of
Illinois (Range 2-Column 12).   These data are the results of a re-
cently completed literature review.

     The conclusion to be drawn from this review of landfill leachate
quality (as summarized in Table 2)  is that its composition is highly
variable from site to site.  !n addition, the data show that even at
a given landfill, considerable variation is encountered with resoect to
both space and age.  That is,  variability is a factor within a landfill
and also over the history of the site.  Consequently, it is concluded
that landfill leachate quality cannot be predicted a pr ipr ? : and that
this quality is even variable at a given site.

                              LEACHATE
     Leachate treatment systems have been evaluated on a laboratory-
scale at Drexel University.  In one study'/, the purpose was to character-
ize the biodegradat ion of organic matter both with and without the supple-
mentary addition of chemicals.   The system consisted of f've aerobic
units which were treated in the following manner:  (l) control-no
treatment; (2) addition of sodium hydroxide to pH 9; (3) addition of sodium
hydroxide to pH 11; (4) addition of lime; and (fj) addition  of lime plus
sodium carbonate.  Otherwise, all units were handled in the same manner.
This procedure included preparation of an activated sludge culture by
aerating leachate.  Each experimental  unit was seeded with this culture
and was aerated at a rate of 9^ liters of air per gram COD  (1500 cu ft per
Ib COD).  During the testing, all settled solids were recycled to the
aeration tank with no sludge wastage.   The aerat'on treatment systems
were operated on a continuous basis with a hydraulic residence time of
five days.   /


     The COD values decrease quite rapidly during the first six days
and thereafter approach a  limit.  The results indicate that there are
components of leachate which are not amenable to treatment  in an aerobic
system.  The time of adaptation of microorganisms for treatment of the
organic fraction of leachate may be considerably longer than normal sewage.
Volatile solids concentrations in these tests were low when compared to
normal activated sludge systems.  This may be one reason for the long time
required for stabilization.

     Figure 2 shows the high variation in the concentration of total dis-
solved solids in the treated effluent.  The cyclic variation of

-------
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           -16-

-------
 several  rystems  is  of  interest,  but not all of  the  systems  show  this
 phenomenon.   Since  the withdrawal and addition  of  leachate  was constant,
 there was  no  reason for  the  cyc""c effect.  Only pretreatment with  lime
 gave any type of stability and COD reduction.

     Thus, neither  biological waste treatment nor chemical-physical
 treatment  separately is  able to  reduce the BOO  more  than eighty  per-
 cent.   In  fact,  the efficiency of the chemical-physical process  is  con-
 siderably  below  this level.   It  is hypothesized that  two reasons exist
 for the  poor  removal efficiency  of each individual  system:   1} the  large
 percentage of high  molecular weight organic materials, and  2) the bio-
 logical  inhibition  caused by heavy metal  presence.  The physica!-chemical
 treatment  is  needed to remove the metals  and also to  hydro]yze some of
 the organics, and biologies'  treatment to stabHTze  the cfegradabie
 organ ic  matter.

     In  addition, biological  treatment alone does not  remove significant
 amounts  of the heavy metals.  In fact, biological units may  be inhibited
 due to the toxic effects of  the  metals.   Consequently, chemical and/or
 physical processing is needed for the removal of substantial amounts of
 these materials.  Lime treatment is particularly effective  in that  it
 creates  the alkaline conditions  under which the metals Lccufne insoluble.

     The removal  of heavy metals during lime precipitation  depends  upon
 the formation of insoluble metal compounds, primarily  hydroxides, at
 alkaline pH.  The optimum set of conditions is  not  identical for all
 metals,  and the  result is that it is impossible to achieve  the maximum
 theoretical removals for each metal within a single tank.   !n general,
 the optimum pH levels  are in the range of 7-10.3    (see Table 5).
 Hexavalent chromium is not removed by lime addition unless  it has pre-
 viously  been  reduced to  trivalent chromium.

     These studies  demonstrated  that the  aerobic treatment of sanitary
 landfill leachate is feasible and that pretreatment may be  required.
 Lime precipitation  appears to be the most favorable pretreatment method.
 The organic fraction of  leachate was found to contain substances not
 readily  assimilated  by the microorganisms, and  it was hypothesized  that
 chemical treatment  is  needed to  remove these organics.

     Chian and DeWasle have  recently completed  an extensive  review  of
 leachate treatment  techniques.'"  Their conclusion was that  leachate
 collected  from recently  leaching landfills is best treated biologically.
 This is  because  the  organic  fraction of such leachate  is composed pre-
 dominantly of free volatile  fatty acids which are readily biodegradable
 by either aerobic or anaerobic means.   On the other hand, leachate  from
 older landfills  is more efficiently handled by  chemical-physical  pro-
 cesses,  because  these  organics are more resistant to biodegradation.
 They also concluded  that activated carbon and reverse osmosis were  the
 most efficient chemical-physica1 methods  Fn terms of the removal  of
organics.

                                    -17-

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                          Table 5

                                                                          1
THEORETICAL REMOVAL OF HEAVY METALS DURING LIME PRECIPITATION"



                                           Theoretical Effluent
Metal	Optimum pH	Concentration, mq/1	        m
Cadmi urn                        10                  1.0

Hexavalent chromium

Trivalent chromium           8.5~9-5                <1

Copper                       9.0-10.3              0.01

Soluble iron                    7

Lead                           --                 <0.1

Nickel                         10                  0.01

Zinc                           —                 <0.1
-PATTERSON, J.W. and R.A. Minear.  Wastewater Treatment Technology.
 Prepared for Illinois Institute of Environmental Quality.  279 pp.
 Published by NT1S, Springfield/, Va.  PB 20*» 521.  1971.
                             -18-

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      The  compilation  of data  presented  by Ch'an and  DeWalle  indicate
 the  following  range of COD  removal efficiencies for  various  treatment
 methods:  0  to  98  percent for  aerobic  biological;  87  to  99  percent  for
 anaerobic biological;  17 to kO  percent  for aerobic/anaerobic biological;
 0  to kO percent for chemical  precipitation with alum, ferric chloride,
 ferrosulfate or lime;  3^ to 3k  percent  for activated carbon  and  ion-
 exchange; 0 to ^8 percent for chemical  oxidation;  56~98 percent  for  re-
 verse osmos is.

      As a means to bring order  to  the wide disagreement found,  in  the
 literature, Chian and  DeWalle postulated the age  of  the landfill affected
 the  character  of  the  leachate.  and that this character  is  best measured
 in terms  of the ratios of chemical oxygen demand  to  total  organic  carbon
 (COD/TOC) or of biochemical oxyaen demand to chemica1 oxygen demand
 (BOD/COD) (Table  6)16.

                                SUMMARY

      The  state-of-the-art concerning the composition and treatment of
 sanitary  landfill   leachates has been assessed.   The most obvious char-
 acteristics of leachate  are its strength and its variability.  Leachate
 is generally of much greater  strength than domestic sewage.  This  is
 especially  true in terms of organic materials and the potentially  toxic
 heavy metals.   As  important a characteristic as strength is  the varia-
 bility of leachate composition.   Leachate quality not only fluctuates from
 landfill  site  to  sit2, but also from time to time at one landfill.  Changes
 over  time result  from  differences in seasonal hydrology and microbiologi-
 cal activity.   Rainy weather may dilute the leachate, but, at the  same
 time, may flush out large quantities of pollutional material.  The typi-
 cal  pattern observed over many years is that the pollution potential of
 leachate  is greatest during the first five years or so after placement,
 but  that  leachate  strength remains significant  for as long as ten  to
 twenty years.   This sequence  is  encountered because the microbiological
 processes responsible  for the decomposing of the solid wastes are  rela-
 tively slow acting and are first directed at the most readily biodegrad-
 able components of the waste.

     Considerable differences are encountered in  leachate quality when
 comparing landfills.    In addition to the seasonal, hydrologic and age
of landfill  factors mentioned above,  there are  several other reasons
 for this observation.   The chemical  nature of the wastes accepted at
 the  landfill has a marked effect on the composition of the leachate.
The land disposal  of  industrial  liquid and solid wastes  is critical
 in this 1ight.

     The variability and the strength of leachate have  important waste
 treatment  implications.  First,  the sheer magnitude of the measures of
pollution  potential dictate the  use of thorough waste treatment.   Second,
 the changes  encountered from landfill  to landfill  are such that  waste
                                   -19-

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treatment techniques applicable at one site are not necessarily directly
transferable to other locations.   That is, it may be mandatory that each-
instance be separately engineered to achieve adequate treatment.  Third,
the fluctuations in leachate quality which occur over both short and
long time intervals must be accounted for in the treatment design.  Not
only must processes be designed to efficiently treat the waste flow from
minute to minute, but the design  must also reconcile the possibility
that treatment techniques which work well for a young leachate may be-
come wholly inadequate as landfill age increases.

     It is apparent today that most landfill  leachate cannot be
treated adequately by just conventional  chemical/physical treatment or
conventional biological  treatment.  Rather, what is needed is a com-
bination of the two approaches with perhaps a supplementary form of ad-
vanced wastewater treatment.  The purpose of this project is to inves-
tigate, at both the full and bench-scale levels of operation, the effi-
ciency of treatment afforded by these processes.
                                -21-

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                    III.  LEACHATE TREATMENT SYSTEM

     The leachate treatment facility being used in this study is located
at the GROWS Landfill  in Tullytown, Falls Township, Bucks County, Penn-
sylvania (see Figure 3).  The plant is designed to provide maximum opera-
tional flexibility in  order to permit full-scale testing of a variety of
treatment sequences.  Plant design and treatment modes are considered in
subsequent paragraphs.

     The sanitary landfill has a surface area of 50 acres.  The landfiH
will  be filled with about 1,400,000 cu m of refuse over the next several
years.  The time required to fill the landfill depends upon many unknown
factors, but it is estimated that it will probably be between five and
ten years.   The receipt  of refuse is about 800 tons oer day.  Eighty-
five  percent of the refuse is from municipal  cources.  The remainder is
industrial  and commercial.  The landfi'l is also permitted to accept
sewage sludge and selected industrial  liquid  wastes.

     The landfill is located in the semi-humid northeastern part of the
United States.  The ninety-eight year monthly average precipitation and
temperature data are given in Table 7-   In this region there is a net
positive infiltration  of rainfall into the landfill.   As long as there
is a  net positive infiltration, leachate will eventually begin to be
produced by the landfill.

     Because of these  meteorological conditions and the site hydrologic
situation,  groundwater pollution potential existed.  To alleviate this
pollution potential  the  Pennsylvania Department of Environmental Re-
sources required the landfill to be underlain by an impervious asphaltic
membrane.  This membrane system was designed  to collect and transport
the leachate to the leachate treatment planty.

     The treated effluent is discharged to the Delaware estuary.  The
river zone is tidal  and  flow figures are not  available.  At the nearest:
gage  (Trenton) the drainage area is 6700 square miles and the projected
low flow is 33,000 liters per second.   The discharge of treated effluent
directly to the Delaware River occurs only during the months of December
through April.  During the remainder of the year, the effluent is re-
turned to the landfill.   The landfill  has ample storage capacity in
the pore space so that storage for six months does not create any diffi-
culties.  The effluent  is spread on the  landfill using aeration nozzles.

     The treatment plant operates under permits from the Commonwealth of
Pennsylvania Department  of Environmental Resources Water Quality Section
and the Delaware River Basin Commission.  The effluent criteria for the
facility are summarized   in Table 8.
                                 -22-

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                               Tab^e 7

          Precipitation and Average Monthly Temperature Data
                          Trenton, New Jersey-

Month

January
February
March
Apr! 1
May
June
July
August
September
October
November
December
Rainfal 1
cm
8.87
6.58
9-75
8.15
9.19
9.14
10.62
12.12
8.89
7.21
8.03
7.29
in.
3.10
2.59
3.84
3.21
3.62
3.60
4.18
4.77
3-50
2.84
3.16
2.87
Temperature
°C
0.8
1.0
5.1
11.1
16.9
21.7
24.2
23-3
19. C
13.5
12.7
1.7
°F
33.4
33-8
41.3
52.3
62.7
71.4
76.0
74.3
67.6
56.5
45.1
35.1
Total                 104.85    41.28
  Trenton,  N.J. Weather Bureau,  30 Year Average.
                                 -23-

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Figure   3.^   Location of L«*ch«M Trwwwnt Plant
         '
                                 *-^'   Newbold   Island
                                     MANSFIELD
                                         ._  UnimpraneddM
                                   U. S Roult        Sutt Rout*
                                   TRENTON WEST, PA.— N. J.
                    -2k-

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                     Table  8

                    EFFLUENT
GROWS SANITARY LANDFILL LEACHATE TREATMENT FACILITY
SUMMARY OF EFFLUENT CRITERIA*FOR
Parameter
BOD
Ammonia -Nitrogen
Phosphate
Oi 1 and grease
1 ron
Zinc
Copper
Cadmium
Lead
Mercury
Chromium
Maximum Concentration
mq/1 iter
100.0
35.0
20.0
10.0
7.0
0.6
0.2
0.02
0.1
0.01
0.1

*Commonwealth of Pennsylvania Department of Environmental
 Resources and Delaware River Basin Commission.
                          -25-

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                           Design Overview

     The purpose of this section is to briefly summarize the design
criteria and to discuss the design itself of the treatment facility.
The effluent limits have been mentioned above and presented in Table
8.  The following paragraphs are devoted to a discussion of the leachate
quantity and quality as estimated for design purposes.

Design Flow

     The source of liquid waste is the leachate which results  from the
degradation of refuse and percolation of rain water through the
landfill.  In addition, as the treated effluent is recycled to the
landfill during the summer months, and to the Delaware  River during
the winter, the raw leachate volume includes this recycled effluent.
The quantity of waste which is generated is dependent upon many indivi-
dual factors of the landfill.   The maximum genc-ation of waste (includ-
int the recycled volume) for design purposes was estimated to be about
20 liters per sq m-week at this site.  However, the production of
leachate is dependent upon the time cycle, both as to placement and to
the season of the year.  Leachate itself occurs as the  result of the
excess of infiltration over evapotranspiration and the  soil moisture
deficit.  Thus, the actual generation of leachate depends upon precipi-
tation patterns, landfill moisture and effluent recycling.

     Since the generation of leachate is a function of  the age of the
fill, not all the expected leachate will be produced simultaneously.
There is an initial period of  operation when the landfill comes to
field capacity, followed by an extended period of leaching of contami-
nants, after which there exists a state of degradation  when the leachate
is no longer of a polluting nature.   It is possible that some portions
of the landfill will  be in this latter state when the final parts of the
landfill are being completed.   Hence, the maximum flow  of 20 liters per
sq m-week is a value which may never be attained for extremely strong
leachate.  This maximum flow rate was determined using  the site meteoro-
logical data presented in Table 7 and the procedure developed by Remson,
Fungaroli and Lawrence .

Design Leachate Characteristics

     The leachate strength parameters used for design purposes are
presented in Table 9.  These were obtained through a modest sampling
program conducted during the very early stages of the landfill.  How-
ever, as discussed in Chapter  II, the exact character of waste is diffi-
cult to predict for a number of reasons, including the  fact that it is
subject to dilution when the infiltration is high.  In  addition, be-
cause of the on-site variability, it is possible that single samples do
not accurately reflect the character of the waste.

                                   -26-

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            Table 9

 DESIGN  LEACHATE  CHARACTERISTICS
Constituents	Raw Leachate*
 BOD                          ]500
 Suspended Solids             1500
 Total  Solids                 3000
 Percent Volatile              55
 pH, pH units                 5.5
 Chlorine                     200
 Iron,  total                  600
 Zinc                          10
 Chloride                     800
 Organic Nitrogen             100
 Nitrate                       20
 Sulfate                      300
 Copper                        1
 Hardness                     800
 Alkalinity                   1100
 Color, standard units         50
 Flow,  mgd                    . HA
 Temperature, °F /             80
*A11 units are mg/1 except pH, color,
 flow, and temperature.
                -27-

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Design Concept

     As discussed in Chapter I!,  a combination of chemical/physical
treatment plus biological  treatment is often  required for leachate treatment.
The principle is that the  chemical/physical  units can be used for the
removal of refractory organics  and for pretreatment prior to the
biological process.   In the latter case,  the chemical/physical processes
are used for the removal of potentially inhibitory materials such as
heavy metals and ammonia-nitrogen.  The function of the biological units
is the stabilization of organic matter and the oxidation of ammonia
nitrogen.  As a result of  the findings discussed in Chapter !! and the
design leachate quality, this treatment plant was designed to consist
of lime treatment and sedimentation followed by activated sludge and
chlorination.  Air '-.tripping of ammonia and  nutrient addition are in-
cluded in the chemical/physical section.   A  schematic of the leachate
treatment plant appears as Figure b.

Leachate Collection System.  The raw leachate is contained within the
lined landfill which was designed to allow for the collection by gravity
of leachate at three locations.  These locations are outfitted with man-
holes from which the leachate is pumped and  transported v!a pressure
lines to the treatment facility.   The leachate enters the plant via a
one thousand gallon holding tank  in which little mixing occurs because the flow
from the individual  manholes is highly variable, and pumped sequentially.

                     Chemical/Physical Section

     The chemical/physical portion of the plant consists of the following:
chemical precipitation and coagulation, sedimentation of precipitate,
air stripping at elevated  pH for ammonia removal, neutralization and
nutrient supplementation.   Each of these are discussed  in the following
paragraphs.

Chemical Precipitation.  In the chemical  treatment phase, the major design
goal was the removal of inorganic materials.  In particular, metals that
may interfere with the subsequent biological treatment process are removed;
also, the metals are removed to achieve discharge standards (Table 8).
As part of the chemical treatment, the biochemical oxygen demand will also
be reduced, but the design percentage of reduction was 30 to 50 percent,
on the basis of the experience with municipal wastewater and with leachate
as discussed  in Chapter II.

     The chemical treatment step consists of flash mixing followed by
quiescent conditions favorable for coagulation as well as sedimentation
of the chenvcal sludge.  Lime has been the only chemical utilized In  this
chemical precipitation step.  However, additional feeders and points of
injection have been provided for  the use of other chemicals if necessary.
Other chemicals which might be used include alum, ferric chloride, synthe-
tic polymers, and powdered activated carbon.

     This unit  is an upflow solids contact reactcr clarifier.  Lime
slurry  is added  to cause coagulation and precipitation of the waste

                                   -28-

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-29-

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materials.  The lime is pumped at a rate commensurdte with the rate of
leachate production.  The lime slurry is flash mixed with the incoming
waste, and mixing, fJocci^at>on and upflow clarification occur within a
single unit.  Solids contact is optimized by variable sludge recycle.
The chemical treatment facility Is a 3-66 m diameter, 3-66 m deep
cylinder with a hydraulic retention time of 1.7 hours at 380 liter/min
flow rate.

     Sludge is drawn off the bottom of the reactor clarifier and placed
in a common sludge holding tank with the waste activated sludge.  Sludge
return pumps are available to recirculate the sludge and mix it with the
incoming waste water to reduce the amount of chemicals which are needed
for precipitation.  (However, the practice to date has been to use lime
and to not recirculate the sludge.).  The amount of sludge that is pro-
duced in this step depends upon the composition of the leachate.  The
design projection was that approximately 5 percent of the flow will be:
produced in sludge at 1 percent solids concentration.

Air Stripping of Ammonia.  As a means of controlling excessive levels of
ammonia in the lime treated stream and in the final effluent, a lagoon
incorporating air stripping of ammonia is included in the chemical/
physical section of the plant.   The lagoon is located cfter the chemical-
precipitation-clarification unit in order to take advantage of the high
pH of the upflow solids contact reactor clarifier effluent and to mini-
mize the solids loading on the lagoon.

     The volume of the lagoon is 950 cu m, thus providing a detention
time of approximately 1.7^ days at design flow.  The primary function
of the lagoon is to encourage air stripping of ammonia by an elevated
influent pH of 10, aeration and high internal recycle with splash plate
to increase the air/water interface.  The lagoon is lined with chlori-
nated polyethylene.  In addition to ammonia removal, the lagoon pro-
vides equalization in terms of both flow and sanitary parameters.

Neutralization and Nutrient Supplementation.  SuIfuric and phosphoric
acids are added to reduce the pH of theleachate prior to entering the
biological waste portion of the process.  Phosphoric acid replenishes
the supply of o-phosphate, a necessary biological nutrient, which is
precipitated and removed following the addition of lime.

                    Biological  Treatment Section

     The biological treatment units consist of two aeration and two
secondary clarifiers.  The units may be operated in series or parallel.
The capacity of each tank is 75,710 liter, which corresponds to a 6.6
hour detention time at the maximum flow rate of 380 liter/min.   The
aeration chambers are provided with diffused aerators, each driven by
a ]k.2 cu m per min blower.
                                  -30-

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     Depending on the actual hydraulic residence time  in the aeration
tanks, the activated sludge units were designed to operate  in either the
conventional or extended aeration modes.  !n order to achieve this, the
mixed  liquor volatile suspended solids (MLVSS) would be maintained  in
the range of 3000-8000 mg/liter.  This level is high relative to that
normally maintained in units handling municipal wastewater.  However,  it
is necessary because of the high BOD loading, and because of the require-
ment to remove about 90 percent of the BOD remaining after chemical/
physical treatment.  The MLVSS  is maintained by return sludge pumps
capable of delivering a return sludge flow equal to 200 percent of  the
influent flow.

     The waste sludge from the activated sludge units and from the chem-
ical treatment process are stored in the sludge holding tank.  The capacity
of this tank is 21 cu m, and sludge is removed as required and conveyed
back to the landfill via tank truck.

     Separation of treated wastewater from the MLVSS is achieved by
gravity sedimentation in the secondary clarifiers.   The total clarifier
volume is 47,318 liter, in two parallel independently operable units.
Sludge return is provided with air lifts installed in the final  settling
tank.  A skimming device is located in the settling basin in front of
the scum baffle to remove floating material  which will  be returned to
the aeration compartment.  The maximum surface overflow rate is  20.4
cu m per day per sq m (500 gpd/sq.ft.)  based on the peak flow of 380
1iter/min.

     Final effluent is directed to the chlorine contact tank after
secondary clarification.  The chlorine contact tank provides a reten-
tion time of 20 minutes at the 380 1iter/min flow rate.  The effluent
after chlorination is discharged to the Delaware River or to the land-
fill depending upon the season of the year.   The chlorine contact tank
is a simple baffled tank to assure mixing of the chlorine which  is pro-
vided by hypochlorination.
                                   -31-

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                      IV.  MATERIALS AND METHODS
                         Experimental Systems

     The leachate treatment plant, although designed for chemical/
physical treatment followed by biological treatment, was equipped with
sufficient flexibility to provide for operational evaluation of a var-
iety of treatment sequences.  These sequences are each defined in the
following paragraphs with reference to Figure 4.

System 1 - Chemical/Physical followed by Biological Treatment

     System 1 is the basic treatment sequence with lime tr?atment for
metals removal followed by ammonia stripping and conventional activated
sludge.  System la refers to the use of System 1 when the air stripping
was not used, whereas System Ib signifies tha:; the lagoon was included
in the flow sequence.  System la was tested in the late winter and spring
of 1976, and System Ib in the summer of 1976.

System 2 - Chemical/Physical Treatment

     Two subsystems have been evaluated.  These, Systems 2a and 2b,consist
of lime treatment either with or without subsequent removal  of ammonia by
air stripping.  The system without ammonia stripping (System 2a)  was
evaluated in the winter and spring of 1976; and System 2b in the summer
of 1976.

System 3 "Biological followed by Chemical/Physical Treatment

     This is the reversal of System 1.  This system was studied during
the winter of 19/76.  The results indicated poor treatment efficiency,
mosc likely due to heavy metal and ammonia toxicity.  However, it might
be argued that a sufficient amount of activated sludge had not developed.
Therefore, System 3 wi11 be reevaluated :n order to test this latter
hypothesis.

System A - Biological Treatment

     This system has been tested, the results showing poor treatment
efficiency.  However, as indicated above, the performance might improve
if a previously acclimated activated sludge were available.   Consequently,
System 4 will be operated and tested simultaneously with System 3-

                          Process Monitoring

     An analytical laboratory has been established in a trailer located
immediately adjacent to the treatment plant.  The trailer is outfitted
with the apparatus indicated below and is environmentally controlled
with a heating/air conditioning system.  The need for extensive bench-

                                  -32-

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                                 Table 10

                     ROUTINE LABORATORY CHEMICAL ANALYSIS
                                 Dal ly
 lU m
                                 Method
                        EPA
                       Storet
                         No.
         Detec-
         tion
         Limit
pH
Chemical oxygen demand
Dissolved oxygen
Mixed liquor suspended solids
Mixed liquor settleable solids
Dissolved sol ids
Volatile suspended solids
Total residue
Dichromate reflux
Electrode
Gooch crucible
Gooch crucible
Gooch crucible
Gooch crucible
Gooch crucib'e
00299
70300
50086
00530
00520
00500
                            Weekly
Alkalinity
Biochemical oxygen demand
Total hardness
Kjeldahl nitrogen
Ammon i a nit rogen
Phosphate
Sulfate
Chloride
Total i ron
C h rom i urn
Copper
Cadmium
Lead /
Mercury
Zinc
Nickel
Calcium
Magnesium
Sod i urn
Potassium
Titrimetric (pH A.5)
Probe  ethod
Titrimetric
Titrimetric
Disti1lation
Persulfate digestion
Gravimetric
Ti trimetric
AA*
AA
AA
AA
AA
Mercury analyzer
AA
AA
AA
AA
AA
AA
OOA10
00310
00900
00625
00610
00665
009*6
009^0
                            Aperiodic
         0.02
         0.02
         0.01
         0.002
         0.05
         0.0002
         0.005
         0.005
         0.003
         0.005
         0.002
         0.005
011 S Grease
Hexane extraction
*Atomic Absorption Spectroscopy
                                  -33-

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scale testing and the large number of analyses needed for process con-
trol and monitoring made the on-site laboratory mandatory.  The labora-  '
tory is operated by the chemist-operator employed specifically for this
project.

     The chemical analyses performed routinely are presented in Table
10.     These have been selected on the basis of four criteria:  they
represent the most common chemical parameters used in the literature
to characterize landfill leachate; they provide sufficient data to com-
pletely evaluate the unit operations, process and total  system effi-
ciency; they are needed for orocess control; and they are required to
specifically define the leachate.

     All analyses are performed in accordance with Standard Methods
13th Ed. 1971; ASTM Standards pt-23, 1972 and EPA Methods, 197*» EdJ9-2H
The analyses are performed on total samples as opposed to filtrate
samples.  Some preparation of the raw leachate is required.

     Electrometric techniques are i'sed in the determination of dissolved
oxygen  (with periodic checks using the Azide Modification of the Wlnkler
lodometric procedure), pH, and dissolved solids.  Atomic absorption spec-
troscopy is used for iron, chromium, copper, nickel, zinc, bodium, cadmium,
lead,  and potassium.

     A number of sampling points are used in the analysis program.
Routinely, samples are collected of (l) the raw leachate; (2) chemicai/
physical sedimentation tank effluent; (3) lagoon effluent? (k)  mixed
liquor; and (5) biological sedimentation tank effluent.   In addition,
samples are collected on an irregular basis from the three landfill man-
holes and directly from the individual treatment units.   In all cases,
every effort is made to ensure that a representative sample is  obtained,

                        Bench-Scale Testing

     As a supplement to the full-scale treatment processing, some smaller
scale work has been undertaken.  This effort serves two purposes.  First,
it allows the operator to readily develop operational guidelines.  For
example, jar tests have been used to determine proper chemical  dosages.

     The second purpose is to provide an opportunity for evaluating addi-
tional treatment techniques.  Specifically, bench-scale testing has been
used to evaluate activated carbon treatment of raw leachate.  Granular
activated carbon has been used in column studies to obtain performance
characteristics.  The results are discussed in Chapter 5.   Additional
carbon studies, as a final effluent polishing technique, will be under-
taken in the coming months.
                                   -34-

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                         Statistical Tests

     The following notation  is used throughout: n, number of data points;
x, arithmetic means; and s,  standard deviation.  The mean is calculated
as
and the standard deviation as
                           s
                                   (x - x;)
                                    n-1

where the Xj are the n data points,

and the coefficient of variation is

                          cv = —
                               x

The value of the coefficient of variation decreases with decreasing
variabi 1 i ty.
                                   -35-

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                         V.  RESULTS AND DISCUSSION


                             Preliminary Results

Raw Leachate Quality

     A summary of actual leachate quality is shown in Table II.  These
data are a summary of the entire set of results.  As is evident from a
comparison of Tables 9 and 11, there are significicant differences
between the two.  These changes toward increased leachate strength are
seen mainly between the design and actual raw leachate organic matter,
dissolved solids, pH and ammonia.  The biodegradable organics concentra-
tion is three times the design level.  Dissolved solids are an order of
magnitude greater, caused by increased hardness,  organic matter and
chloride.  The ammonia concentrations actually observed have been ex-
tremely high and have been a source of oper^t^g problems especially in
the biological units.  The factors influencing this difference between
the projected and observed leachate quality have been discussed in Chap-
ter II.

     Considerable variability in the raw leachate quality has been noted
on a day-to-day basis.  The influent COD data are presented in Figure 5
to show  this variability.  An additional indication  is provided by
the coefficient of variation data provided in Tablet, columns 3 and
10.

Lime Dosage

     Jar tests were carried out in the laboratory in order to determine
proper dosages for the lime treatment unit.  In the first series of tests,
three types of lime were monitored for their ability to raise the pH of
raw leachate to 10.0.  The 1imes' used were high magnesium lime, high
calcium quick lime and high calcium hydrated lime.  The results may be
summarized as:
                                                    Dosage
                                             lb/1000 gal   kg/cu m

          High Magnesium Lime                     125        15
          High Calcium Quick Lime                  52       6.2
          High Calcium Hydrated Lime               50       6.0

It is economically impractical to use the high magnesium because its
properties are such that to raise the pH to 10.5 requires 30 kg per
cu m (250 Ib per 1000 gal).

     Required oosages to obtain pH 10.0 are nearly identical for both
types of high calcium lime.  For pH greater than 10.0, the high calcium
quick lime becomes more efficient and hence is desirable economically.
However, the slaking characteristics of the quick lime have caused pro-

                                    -36-

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                                Table II
                   LANDFILL  LEACHATE  CHARACTERISTICS*
        	I tern	Concentration'*'

        Biochemical oxygen demand  (5-day)        4,460
        Chemical oxygen demand                  11,210
        Total solids                            1,154
        Suspended  solids                         1,994
        Dissolved  solids                        11,190
        pH, pH units                              7.06
        Alkalinity, as CaCO^                     5,685
        Hardness,  as CaC03                       5»H6
        Calcium                                    651
        Magnesium                                  652
        Phosphate                                 2.81
        Ammonia-N                                1,966
        Kjeldahl-N                               1,660
        Sulfate                                    114
        Chloride                                 4,816
        Sodium                                   1,177
        Potassium                                  959
        Cadmium                                  0.043
        Chromium                                 0.158
        Copper                                   0.441
        Iron                                       245
        Nickel                          j         .531
        Lead                            '         .524
        Zinc                                      8.70
        Mercury                                  .0074
*These values represent the arithmetic mean of all raw  leachate data.

+A11 units mg/liter unless otherwise noted.
                                  -37-

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-38-

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blems with pumping the resultant slurry so that this lime cannot be used
with the available lime feed system.  On the other hand, the hydrated
lime does not offer such problems, and consequently, the high calcium
hydrated lime is being used.

Sulfuric Acid Dosage

     The amount of sulfuric acid required to lower the clarifier efflu-
ent to 6.5 has been determined.  To do this, approximately 0.6 ml of
concentrated sulfuric acid per liter leachate (0.6 gal/1000 gal) is re-
quired.  The actual dosages used are presented later in this chapter
as part of treatment costs.

Phosphoric Acid Dosage

     The need for a phosphoric acid supplement became apparent from three
lines of evidence:  (a) very low phosphate levels in the chemical/physical
effluent; (b) unrealistically  low values obtained in the biochemical
oxygen demand test; and (c) poor biological treatment performance follow-
ing the chemica1/physica1 process..  These points all indicate that the
chemical/physical treatment effluent is phosphorus deficient, and that,
if biological treatment is to follow, it must be supplemented with phos-
phorus.  Additional evidence was collected by performing a series of
BOD^ tests in which a variable amount of phosphorus supplement was added
to the bottles.  It was observed that the BOD increased with the amount
of phosphorus.  In addition, bench scale tests indicated greater acti-
vated sludge production when o-phosphate was added.  Thus, it has been
concluded that orthophosphate, as phosphoric acid, should be added to
form a nutrient supplement.

     The preliminary calculation of phosphoric acid dosage has been made
on the basis of providing, a ratio of  BOD:N:P of 100:5:1-  This  is approx-
imately 15-23 liter (4-6'gal) phosphoric acid per day.  More recently,
however, the criterion is to add phosphoric acid so that there is measur-
able o-phosphate in the bio-unit effluent.  This amounts to about 3-8
liter (1 gal) of phosphoric acid per day.

                SYSTEM  1  -  PHYSICAL/CHEMICAL  PLUS ACTIVATED SLUDGE

     System  1  consists of chemical/physical treatment followed by
activated sludge.  The early attempts(winter and spring 1976) to develop
an activated sludge culture were not successful.  As discussed in connec-
tion with Systems  3  and 4, phosphorus limitation and ammonia toxicity
inhibited these efforts.  These two difficulties were overcome by the
addition of phosphoric acid as a neutralizing agent for the lime treat-
ment effluent and by the use of air stripping of ammonia.  System #1 was
successful only after the implementation of these measures and, as a
result, this discussion is limited to the time period after implementa-
tion.

                                 -39-

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     The BOD, COD, and ammonia-N data showed a dramatic
improvement in treatment efficiency during August.   Approximately
four weeks were needed to develop the activated sludge micro-
organisms to the point where they were capable of rapid growth at the
expense of the leachate substrate.  Table  12  shows the results follow-
ing the successful adaptation of the activated sludge.  The starting
date for analysis of these data was chosen as August 1, 1976, which
marks the point at which the activated sludge had become fully accli-
mated in terms of ammonia-N, BOD and COD removals.

     The results presented in Table  12  demonstrate the high level of
treatment efficiency attainable with System  1.   This treatment, system
can achieve removals greater than ninety percent for ammonia, BOD, COD,
and iron; and greater than two-thirds for suspended solids, alkalinity,
magnesium, kjeldahl-N, cadmium, lead, mercury, and  zinc.  Relatively
poor removals of chromium and nickel were achieved  with System #J.
Chromium removals have averaged 28.6 percent, and this low efficiency
is attributed to two factors.  In the first place,  any hexavalent
chromium will not be removed by lime precipitation  without previous
oxidation to the trivalent state; and, in the second place, the pre-
cipitation of trivalent chromium at pH 10 is not optimal (See Table 5).
This is because the solubility of chromic hydroxide is at a
minimum at pH 8.5-3-5 and increases with increasing pH.  During the
time period represented by Table  12,  the clarifier pH was consistently
above 10, and frequently over 11, whereas during the period represented
by Tables  14 and  17  the pH was consistently below 10.  Thus, we are
able to see chromium removals as a function of clarifier pH, and this
opens the possibility that the operator can control pH as a method of
differentially affecting effluent heavy metals concentration.  The
fairly low removals of nickel may also be related to the relatively
low hydrogen ion concentrations.  Based on theoretical considerations
of the solubility of nickel hydroxide, the nickel concentration in the
effluent should be on the order of 0.01 mg/P°, as  opposed to observed
average or 0.27 mg/1.   This observation is perhaps  also due to the
formation of nickel complexes with unknown chelating agents within
the landfill.

     The results observed with phosphates, sulfates and chloride should
be noted.  Little removal of chloride takes place because of its rela-
tive biochemical inertness.  The concentration of phosphates and sulfates
increase during the course of treatment because of  the addition of sul-
furic and phosphoric acids as neutralizing agents.   Initially, both
acids were used in excess in order to encourage the growth of the acti-
vated sludge microorganisms.  That is, the goal was to provide a very
favorable environment in terms of both pH and the nutrient phosphorus.
However, following the successful acclimation of the activated sludge,
the addition of sulfuric acid has stopped while that of the phosphoric
acid has been drastically cut back.  Neutralization is no longer needed
because of the recarbonation effect of aeration in  the lagoon.  The
present criterion for phosphoric acid addition is to provide just enough
                                  -40-

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                             Table 12

SYSTEM  1* TREATMENT PERFORMANCE AFTER ACCLIMATION OF ACTIVATED SLUDGE
                            (August 1976)
       Item                  Concentration        Percentage Removal

                        Influent      EffK-er*
Suspended sol ids
Dissolved sol ids
COD
BOD
Alkal ini ty
Hardness
Magnesium
Calcium
Chloride
Sulfate
Phosphate
Ammon ia-N
Kjeldahl-N
Sod i um
Potassium ,
Cadmi um
Chromi um
Copper
1 ron
Nickel
Lead
Zi nc
Mercury
445
10849
9689
4993
3718
4647
495
819
3172
197
1.62
510
539
992
, 823
0.049
0.105
.313
205
.52
.545
3.64
.015
126
5369
576
60.5
388
1629
109
472
2925
1333
17-8
46.5
141
724
505
0.014
.075
.078
.96
.27
.12
.44
.004
71.7
50.5
94.1
98.8
89.6
64.9
78.0
42.4
7.8
--
—
90.9
73.8
49.1
38.6
71.4
28.6
75.1
99.5
48.1
78.0
87-9
73-3
*This system consists of lime addition, sedimentation, air stripping,
 neutralization, nutrient supplementation and activated sludge.
                                  -41-

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to satisfy the microorganisms'  demand as indicated by ar, effluent con-
centration of about 1  mg/1.   That is, the criterion at present is to add.
enough H^PO/4 so that there is residual phosphate (1 mg/liter) in the efflu-
ent.  This level is one to two orders of magnitude greater than the amount
in the lagoon.

     The difficulties  in obtaining a healthy culture of activated sludge
haVe been overcome.  The operating experience indicates that "he earlier
problems were in fact  due to ammonia toxicity and phosphorus limitation.
The ammonia stripping  lagoon has maintained the concentration of this
inhibitor below toxic  levels.  The mean ana standard deviation of the
lagoon effluent ammonia concentration are such that 99 percent of the time,
the feed to the activated sludge unit is less than k2$ mg NH3~N/liter.
The corresponding raw  leachate concentration is 1285 mg NH^-N/1iter.
Thus, the lagoon has functioned to minimize the shock loading effect of
inhibitory ammonia concentrations.  This »P turn provided an opportunity
for the development of microorganisms capable o~ extracting carbonaceous
BOD.  As this group became established, organic concentrations in the
mixed liquor were reduced and this created conditions suitable for the
development of nitrifying organisms.  Growth of these groups of micro-
organisms has resulted in the low effluent concentrations of both BOD
and ammonia.

     As seen in Table   12,  a considerable change in alkalinity occurs
during biological treatment.  There are two main mechanisms by which
this occurs.   First, the aeration causes some removal of gaseous car-
bon dioxide,  resulting in a shift of the carbonate equilibria and a
change in total carbonate alkalinity.  It is probable, however, that
in this case, nitrification has a more profound effect on alkalinity.
As a result of nitrification, alkalinity is consumed and carbon dioxide
is produced.   Neglecting the effect of biomass synthesis, the theoretical
value is 7-1^ mg alkalinity as CaCOj destroyed per mg NH/j+-N oxidized.
In this study, a ratio of 5.6 mg alkalinity per mg NH/,+-N remove/d has
been observed since the development of the activated sludge culture.
This is in excellent agreement with the theoretical value if one con-
siders that the observed value includes the effects of biomass growth
and air stripping in the bio-units as well  as shifting chemical equi-
libria in addition to  those of nitrification.

Operational Comments

     Operating problems have been  encountered in the biological treatment
unit, and these are being addressed and solved at this time.  The most
serious of these has been a tendency of solids to float in the secondary
clarifier.  The result of this is a decreased ability to achieve the
expected level of solids separation.  The presence of the floating sludge
has been investigated  and is characterized as being the result of three
separate and distinct  causes: flotation, turbulence and denitrification.
It  is apparent that there is some carryover of floating materials to the
clarifier from the aeration tank.  The leachate contains considerable
                                  -42-

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                                                                     -41-

amounts  of  surface  active  materials  capable of  flotation, and  this
contributes  significantly  to  the carryover phenomenon.  The scum con-
trol  device  is  not  capable of handling  the unexpectedly large  amount
of  these materials.  At  the same time,  an excessive amount of  turbu-
lence exists  in the  secondary clarifier.  These first two sources of
the problem  are being  corrected by the  installation of mechanical
skimmers and  construction  of a baffle on the  inlet side of the second-
ary clarifier.

      The reduction  in  solids separation efficiency is compounded by a
propensity of the activated sludge to become  anaerobic and to  rise in
the clarifier due to denitrification.   This is  seen clearly when one
follows  closely the  settleable solids test.   At first, the sludge
settles  properly with  a  dense sludge layer overlain by a clear super-
natant containing little turbidity,  so  that at  the end of 30-3** min
the settleable  solids  are  about 300 mg/Mter.   If the test is  continued
for another  hour, the  sludge comes to the surface in typical rising
sludge fashion.  This  is not a case of  filamentous bulking as  indi-
cated by microscopic examination, the clear supernatant observed in the
settleable solids test,  and the sludge  volume index of approximately
80  mg/g.  Another indication of anaerobic denitrification as the cause
of  the floating sludge is  the repeated  observation of very low DO levels
in  the clarifier.  This  problem has  been accentuated since a portion of
the plant aeration capacity was diverted to the ammonia-stripping
lagoon,  although this  is being rectified by bringing another compressor
on-1ine.

Cost  Data

      Costs  incurred  during the operation of the biological units are
indicated in  Table  13-  The operation  and maintenance costs are shown
for the  operational  period following the initial start-up phase.

      The data indicate a cost of $5-12  per thousand gallons treated.
The high power  costs reflect the demand for electricity for leachate
pumping, effluent pumping, and maintenance of the laboratory in addi-
tion  to  the  requirements for actual treatment.  In the future, it will
be  necessary  to separate these power costs, in order to more accurately
determine the cost of  treatment.  The labor requirement  is approximately
20 man-hours per week.
                SYSTEM 2.  CHEMICAL/PHYSICAL TREATMENT

      This discussion is  presented in two parts.   The first consists of
the results associated only with lime treatment, and the second includes
the ammonia stripping  lagoon.  Full-scale data were collected for System
2  without the  lagoon  during the periods December 11, 1975 to January
12, 1976 and  June 14,  1976 to August 31, 1976, all dates inclusive.  The
results  of this phase  of the treatment  plant  operation are summarized in
Table 14.

                                   -43-

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                       Table  13
OPERATION AND MAINTENANCE COSTS INCURRED DURI.NG THE OPERATION
OF SYSTEM  1  FOLLOWING ACCLIMATION OF ACTIVATED SLUDGE
    Characteristic
Operational Period
Total Flow, gal
            cu m

Lime used, Ib
           lb/1000 gal
           kg/cu m

Sulfuric acid, gal
               gal/1000 gal
               1i ter/cu m

Phosphoric acid, gal
                 gal/1000 gal
                 1 i ter/cu m
    309930
      1173

     29650
      95.7
      11.5

       213
     0.687
     0.687

      26.4
    0.0852
    0.0852
Costs, S/1000 gal
     Power
     Lime
     $1.26
      2.87
       .57
       .21
     Total
     $5.12

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     Table  15 presents the changes  in each parameter attributable to
the  lime treatment.   In very approximate terms, the  lime precipitation/
clarification sequence, System  2a,   removed (see Column 7, Table  14)
one-third of  the dissolved solids and ni trogen;' one-half of the organic
matter, hardness and alkalinity; three-quarters of the suspended solids;
and  ninety percent of the phosphates.  The removal of heavy metals was
one-third of  cadmium, one-half of chromrum and nickel; two-thirds of the
lead and mercury; three-quarters of  the copper and over ninety percent
of the iron and zinc.  The increase  in sulfate is due primarily to con-
taminants in  the chemicals, although oxidation of sulfides may contri-
bute somewhat.  In other words, this section of the  system performed
as expected in pre-treating the leachate prior to biological treatment.

     The results of the overall chemical/physical section including  the
lagoon (System  2b)  are listed in Table  14  which shows the basic sta-
tistical relationships.  Treatment performance in terms of percent
removal efficiency of the lagoon alone and T^ conjunction with lime
treatment are also seen in Table 14.   The primary goal of the lagoon
was achieved as the concentration of ammonia-N was reduced to 317
mg/liter, a level which was found to be tolerable for purposes of
biological waste treatment.  A splash plate, which was installed on
August 9 to promote air/water contact, did not produce an appreciable
effect on lagoon ammonia removals.

     Many parameters other than ammonia were altered while in the lagoon.
There was some stabilization of organic matter as shown by the reductions
in BOD, COD and dissolved solids.  This was mediated by biochemical pro-
cesses and the increase in suspended solids is related to the growth of
microorganisms, as are the reductions in sulfate and phosphate.  The re-
duction in alkalinity and pH is most likely due to aeration effects al-
though nitrification reactions may partially contribute to the observa-
tion.  The reduction of hardness, calcium and magnesium are related and
may be explained by the formation of calcium/and magnesium carbonates.
In this form,  these would not be detected by the usual tests.  Most of
the other changes noted in the lagoon effluent vs. lagoon influent com-
parison are due to the limitations of the experimental techniques or to
the radically variable nature of the raw leachate.

     The overall treatment efficiency of the complete chemical/physical
section is summarized in Table 14.   These data do not include the
effect of neutralization.  The values in the last column (Column 14)
represent removal efficiencies for the lime precipitation/sedimentation/
ammonia stripping sequence.  In terms of organic matter, 56.1 and 56.7
percent of the BOD and COD are removed, respectively.  Approximately
sixty percent  of the ammonia-N and total kjeldahl nitrogen are removed.
The removal  of suspended solids, alkalinity and hardness is about two-
thirds.  The  removal of metals was as follows: 50-65 percent removal
of cadmium,  nickel  and mercury; 70-80 percent of chromium and copper;
88 percent of  lead;  95 percent of z.inc; and 99 percent of iron.
                                   -45-

-------
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-------
                             Table  15

          SUMMARY  OF  EFFECTS  OF CHEMICAL/PHYSICAL TREATMENT"
	 _— 	 — 	 	

Suspended Solids
Dissolved Sol ids
Total Solids
COD
BOD
Alkal ini ty
Hardness
Magnesium
Calcium
Chloride
Sulfate
Phosphate
Ammonia-N
Kjeldahl-N
Sodium
Potassium
Cadmium
Chromium
Copper
1 ron
Nickel
Lead
Zinc
Mercury
PH

Influent
199*
11190
11154
11210
4458
5685
5116
652
651
4816
114
2.81
1966
1660
1177
959
.04
.16
.44
245
.53
.52
8.70
/ .007
7.06
Lime Treatment
Effluent
403
7615
6718
5782
2692
3182
2715
254
645
4265
477
.34
1245
1227
862
721
.03
.09
.11
4.9
.28
.18
.59
.004
9.25
Lagoon
Effluent+
430
5428
5779
4296
2632
1572
1796
163
448
3167
257
.03
317
326
751
639
.021
.04
.10
2.21
.23
.06
.28
.007
8.59

;'-The influent data are those collected during the entire operational
 period,  whereas the effluents figures refer to those periods when the
 specific units were operating.


 All units are mg/1 except pH which is expressed in pH units.
                                    -47-

-------
     Chi an and DeWalle'" have formed an hypothesis, which  is summarized
 in Table  6,   concerning the treatability of raw  leachate.  The BOD/COD
 ratio observed in the study  (Column 2 of Table   14  of the leachate
 was 0.48 and the average COD was 11,419 mg/liter.  Thus, according  to
 Chian and DeWalle, the leachate treatment efficiency obtainable with
 lime should be poor to fair.  In this study  (Column 7, Table 14) the
 lime treatment efficiency for BOD and COD has been about fifty percent.
 Hence,  in terms of the removal of organics,  the Chian and DeWalle^" hy-
 pothesis is supported.  However, it must be mentioned that their hypothe-
 sis did not include the removal of heavy metals, and that the  lime
 treated heavy metal removals have been good  to excellent at the faci-
 lity.

     An additional effect of the ammonia stripping lagoon  is the equali-
 zing effect which, as noted by LaGrega and Keenan23, can be measured in
 terms of both flow variability and quality fluctuations.  The presence
 of the  lagoon has allowed the operator to control the flow leaving  the
 lagoon by control of the pump settings.  T'lis :>as provided flow equali-
 zation to the biological  units.  The increased uniformity of the nature
 of the waste can be seen in Columns 10 and 13 of Table  14  which show
 the changes in the coefficient of variation  through the chemical/physical
 section of the plant.  The coefficient of variation is the ratio of the
 arithmetic mean to the standard deviation, and as such is a measure of
 the dispersion of the data about the mean.  The coefficient, which
 increases as variability increases, exhibits a general decrease through
 the lagoon.  This is seen for all parameters except phosphate, cadmium,
 chromium, copper, iron, magnesium, hardness and mercury, for which  the
 data become more variable through the lagoon.  This is not entirely un-
 expected.  The concentrations of some of these parameters are near  the
 detectable limit, and hence variability may be high.  The observation
 that several of these are heavy metals has not been satisfactorily  ex-
 plained.

 Operational Comments

     The primary operational factor has been the chemicals required
 for precipitation and neutralization.  A summary of these  is presented
 in Table   16.  The rows labeled, average applied dose, have been cal-
 culated by omitting those days on which chemicals could not be added
 because of equipment malfunctions.

 Cost Data

     The cost of materials and electricity is appended to Table
 units are given in terms of dollars per one thousand gallons of leachate
 treated.  The cost has been $2.80-$3.24 per thousand gallons.  The  power
 costs are quite high, reflecting energy consumption not only for chemical
 treatment, but also for leachate pumping, air compressors and the labora-
 tory.  The cost of operation has come down recently as the phosphoric and
 sulfuric acid requirements have dropped considerably as experience  has
 been gained.  Manpower costs for operation and maintenance  is  approxi-
mately twenty hours per week.

                                   -48-

-------
                           Table  16




    SUMMARY OF OPERATION COSTS DURING EVALUATION OF SYSTEM 2


'
Flow, average gpd
Ipd
total gal
total cu m
Lime, average applied dose,
lb/1000 gal
kg/cu m
total lb
kg
h^SOij, average applied dose,
gal/1000 gal
1/cu m
total gal
total liter
H^POi,, average applied dose,
gal/1000 gal
1/cu m
total gal
total liter
Costs, $/1000 gal .
Power
Lime
H2SO^
HoPOj,
During Operation
Without Lagoon
23,487
88,908
4,227,736
16,002

28.6
3.43
105,455
47,877

0.55
0.55
1,525.1
5,773

.094;
.094'
199.9
757

$1.26
.86
0.45
.23
During Operation
With Lagoon
19,897
75,318
1,571,875
5,950

40.1
4.81
63,050
28,625

.64
.64
978
3,702

.099
-099
152.1
976

$1.26
1.20
0.53
.25
Total
$2.80
$3-24
                               -49-

-------
                            SYSTEMS  3 and k
                            —_______                                    ^

     These treatment sequences were tested in full-scale during the
late winter and early spring of 1976.  Severe problems were encountered
in achieving successful treatment.  The primary reason underlying these
problems was the inability to develop a healthy activated sludge.  Approx-
imately eight weeks were allocated to attempts to adapt a sewage activate'
sludge culture to the raw leachate.   After this did not succeed, an inves-     ^
tigation revealed that growth of activated sludge was not possible because
of ammonia inhibition and phosphorus limitation.  The problems were de-
monstrated by the observations that the average concentrations in the
biological units during this time were 9^0 mg/liter of ammonia-N and
less than one of phosphorus.  The data thus indicated that in the aera-
tion tanks, the ratio of BOD:N:P was 6620:760:1 which is in marked con-        ^
trast to the usual recommendations which are in the range of 90-150:5:^-

     The phosphorus limitation was inve?*:!c?tcd in two ways.  First,
replicate BOD tests were set up with varying additions of phosphate
buffer.  It was found that the BODtj increased with the phosphorus addi-
tion up to an upper level, indicating that, within this range, phos-          "
phorus was limiting.  As a result of this finding, the BOD procedure
was modified by the addition of sufficient phosphorus to overcome the
1 imitation.

     Second, a bench test was initiated to evaluate the hypothesis that phos-
phorus limitation was the reason for the poor development of activated sludge.*
The tests consisted of once daily batch draw-and-fill experiments in which
the increase in settleable solids was used to monitor the growth of acti-
vated sludge.  The control reactor received raw leachate only whereas
the sample reactor received raw leachate plus seven ml of BOD phosphate
buffer per liter of raw leachate.  Thus, in the sample reactor, the BOD:
N:P ratip was about 118:13.5:1.  The results are summarized in Table 17.
It is se4n that over the short-term, there was an apparent positive im-
pact upon the production of activated sludge and the utilization of COD.
However, when the tests were continued for several weeks, it became ob-
vious that there was no effect of phosphorus addition on either the
development of activated sludge or the removal of organics.

     The results of these experiments have been interpreted in the follow-
ing manner.  First, the biochemical  oxygen demand tests, and the chemical
analyses showed that the leachate was severely phosphorus limited.  This
problem became more serious when biological treatment followed lime add»-
tion because of the precipitation of calcium phosphate salts in that         ^
unit.  Secondly, the batch draw-and-fill experiments showed that alle-
viation of the phosphorus limitation alone is noi. enough to encourage
the growth of activated sludge microorganisms.  It was concluded it would
be necessary to reduce ammonia concentrations to a non-inhibitory level
before successful biological treatment could be achieved.  Consequently,
the ammonia-stripping lagoon was started up prior to evaluating System  1.    ^
                                     -50-

-------
                               Table  17


Results of Batch Draw-and-Fi11 Activated Sludge Experiments to Determine
the Extent of Phosphorus Limitation.  Results show growth of activated
sludge as ml settleable solids per  liter, and COO as mg/Hter.
\BOD N:P
^\
time, days^\,


0
1
2
3
k
5
6
7
8
9
0 /

2
3
^
5
6
Control
6620:760: 1

influent effluent
COD COD SS
12813
7704
9339
—
8388 26
12868 10698 20
10193 15
11603
NR
9912
--
5963
9012 7115
13174
. 8606
8221
NR
Sample
118:13.5:

influent
COD
12813
7704
9339
—
8388
12868
10193
1 1603
--
9912
--
5963
9012
13174
8606
8221


1

effluent
COD SS




40
7597 40
35





7115




17
18
19
6349
         5625
6349
           5469
                               -51-

-------
                             SYSTEM 5

     Although as yet Incomplete, studies of the potential of carbon
absorption for leachate treatment have been undertaken.  The results
of the evaluation of carbon treatment of raw leachate are presented
here.  Any testing of the process as an advanced waste treatment
technique has been postponed until the beginning of the second year.

     The preliminary evaluation of this system (System 5 ) has been
carried out for raw leachate treatment.  These data are presented in
Table  18.   These tests have been performed with an upflow column of
depth 0.3 m and diameter 0.^6 m, containing 15-9 kg of granular acti-
vated carbon.  The influent f!ow was 38 liter/min, thus providing a
hydraulic loading rate of 232 liter/min/sq m.  As shown in Table !8,
no appreciable treatment can be attributed to the carbon treatment.
It should be noted that excessive suspended solids loading and influ-
ent variability contributed to this finding.  The effect of the solids
is to cause blockages and hence reduce process efficiency.  The influent
was not constant dur'ng any of the tests because it was drawn from the
actual plant influent.  Therefore It is impossible to calculate re-
moval efficiency.  However, it is evident from Table  18  that no renova-
tion is occurring in the carbon columns.  Hence, it is concluded that
carbon adsorption is not appropriate when applied to raw leachate,
although, as mentioned above, it may be suitable for final effluent
polishing.
                                    -52-

-------
TabJe 18
Mr or MULT! or CAMOU uiatr
or MM i nunrtTf
tlm,- ml*
Mil f1«t.
»
u
01
T»
m
coo
(l«
»l
I!
01
Tl
TV!
COO
tlm. r*«
»c«i n«u.
M
0*
Tl
TV1
CM
tlm. an
uul Max.
M
01
Tl
T»l
CO*
tlm. ml*
Mttl «•».
11
01
Tl
TW
CO*
tlm, ml*
tM«l '!•>.
IS
n
Tl
TVI
CO*
0
fit 0
I.JI
2MO
I0$70
12950
MM
UfO
0
0
9*
10(4*
11510
$120
HtS
»
Hi 0
too
11100
11920
$220
»$»
0
Hi 0
$10
100(0
I0$*0
,MM
/MM
0
<•> o
770
IOMO
112)0
5010
1001)
0
9*1 0
1120
IOOM
HIM
(tM
M))
5
$0
7.9*
*22M
IOM*
12770
MM
)«M
5
50
(M
l«t$0
11090
»$0
7212
10
100
5M
1 1000
II$M
*no
9*t*
(
M
tM
10(90
IIMO
$1)0
I07M
2
20
500
101)0
10* JO
t)*o
5170
(
M
IOM
5*00
10*10
tlTO
572J
riOH TKVmtXT
!•»!• »««*.l'
10
10*
*.ot
29M'
91*0
12220
)t«0
TOM
8
SO
S«0
lOtio
11210
t»o
Sttt
1)
l»
MO
HMO
115*)
$1M
9921
12
120
Mo'
11100
11790
$0(0
MM
s
M
9M
100 TO
110)0
t)»
954*
12
120
I02C
10274
11290
<99<)
99(5
1$
150
1.09
2S79
I02M
1)110
tllO
5MO
11
MO
550
10)90
I09M
tlM
SM4
IS
IM
JM
107JO
11070
tSM
97(2
IS
ISO
780
9890
10(70
t*20
MM
U
IM
5M
10590
11190
t7)0
9I2«
IS
IM
mo
I01M
M5W
5T»0
Ilt2
20
200
1.1)
MM
10270
1)110
l>7!0
(MO
It
IM
710
103M
11050
tTSO
9226
'9
190
$70
"HO
IIMO
$180
9127
2t
2M
MO
10100
1*700
KOO
$400
a
200
7M
IO)M
II 100
M70
101 19
2t
2M
1210
**>
IO*M
MM
89))
« •
T»S *
15
250
8.11
MM
900
12190
--
57M
17 20
170 200
J'O '-JO
10520 107M
111)0 11170
5070 tMO
M9t 8772
22 JS
220 250
)70 JOO
Ilt90 10(70
11880 11570
5170 5)20
11079 9M)
30
300
5)0
I02M
10770
1870
MM
2«
2M
7M
MOM
117(0
$020
IOOM
M
MO
IOM
102)0
11270
(180
?»M'
coo! »I«I1« wll«








2) J* 29 )J
2)0 IM Z90 120
100 tlO 210 20
10)40 10270 H2M '1 150
10t(0 104*1 11*50 11170
)570 tfTO tlM t2)0
7992 91*2 11(2 <8«t
28 JT It 37
280 )IO JM 370
880 «» 7M t)0
10010 110(0 IflMO 10970
10890 117(0 lino 11*00
M70 t920 t7lo $000
I0)(f 10079 110)2 98tl





















-53-

-------
                            Conclusions

1.  The GROWS landfill leachate is characterized by high organic strength
    and by large day-to-day variations.

2.  Considerable experience has been gained in the operation of activated
    sludge units on raw leachate and on leachate which has received
    chemical/physical treatment.  It has been tentatively concluded
    that this raw leachate must be pre-treated in order to render it
    amenable to activated sludge processing.   The results i-td-'cate that
    the raw leachate inhibits the growth of the activated sludge micro-
    organisms.  Although the presence of heavy metals and low levels of
    phosphorus contribute to this inhibition, it is clear that the ex-
    cessive concentrations of ammonia-nitrogen are primarily responsible.
    At the conclusion of the current operational mode (Spring 1977)> bio-
    logical treatment of raw leachate win  oce:n be attempted.

3.  Although the operation of the chemical/physical units will continue
    for some time in order to gain experience under a wider variety of
    operating conditions, sufficient data have been collected to provide
    an evaluation of this method of treating  raw leachate.  Lime treat-
    ment alone provides removal efficiencies  of approximately 50 percent
    of the organic matter, 75 percent suspended solids, one-third of
    cadmium, and at least 50 percent of the other heavy metals.

4.  The complete chemical/physical treatment  sequence consisting of lime
    precipitation/sedimentation/air stripping achieved the following
    levels of removal efficiency:  56-59 percent of the organic matter,
    ammonia-N and total kjeldahl-N;  65 percent of the suspended  solids,
    and 50 percent or better of the heavy metals.

5.  Activated sludge treatment of the effluent from the chemica1/physical
   , units has been extremely successful.  It  is apparent that the reduc-
    tion in ammonia-N afforded by air stripping lagoon has made  conditions
    more suitable for the growth of activated sludge microorganisms.  The
    lagoon provides ammonia removals of approximately 65 percent result-
    ing in activated sludge influent concentrations of 210-24.5 mg NH^+-N/
    liter (99 percent confidence interval).  Under this condition, the
    activated sludge quickly adapted to the leachate with the result thai:
    effluent BODij concentrations have been consistently less than 100
    mg/liter.  Nitrifying organisms have developed and produced  a nitrified
    effluent with very low concentrations of  ammonia.

6.  Overall, the treatment sequence consisting of chemical/physical  (lime
    precipitation, sedimentation, air stripping, and neutralization)
    followed by activated sludge has produced an excellent final efflu-
    ent with the following characteristics:

-------
1.  Organic matter has been reduced to 61 mg BOOc/liter.
    This corresponds to 99 percent removal.  The corres-
    ponding COD removal efficiency is 3k percent.  The
    effluent BOD to COD ratio is 0.11.

2.  The effluent ammonia concentration is 47 mg/Uter,
    representing 91 percent removal.

3.  Heavy metals are found in the effluent at the follow-
    ing levels (percent removals are shown in pa-entheses):
    0.014 mg cadmium/liter (71.4 percent); 0.075 mg chromium/
    liter (28.6 percent); 0.078 mg copper/liter (75.1
    percent); 0.96 mg iron/liter (99-5 percent); 0.12 mg
    lead/liter (7
-------
                    VI.  PROGRESS EVALUATION

     The original work schedule for completion of project Is shown In
Figure   6.   With only minor alterations, this schedule has been
followed closely.  A few changes are suggested In this Chapter.  These
changes take the form of shifting emphases in light of what has been
accomplished and learned during the first year of the project.  Refer-
ring to Figure 7, one can see the *ork actually accomplished to date.
This includes at least a preliminary evaluation of each of the systems
to be studied.

     Systems  1  and 2,  i.e., those with chemical/physical treatment as
the first step, have been evaluated and the results are very encourag-
ing.  In fact, the success achieved during the summer of 1976 has been
so promising that we propose to continue operating in this mode for the
next six months.  We make this proposal in o^c1* to obtain data over a
wider range of realistic operating conditions, especially those of higher
flows and lower temperatures expected during the next half year.  These
results will be supplemented wfth bench testing, which is presently
being initiated.  The purpose of the bench-scale experiemental program
is to develop kinetic information which can be applied to full-scale
design of chemical/physical and biological units in t^e future.

     Systems  3 and  k have received preliminary evaluation in tests
conducted during months four to seven.  These treatment sequences are
those in which the activated sludge process receives raw leachate.  As
indicated in Chapter VI, the results indicated that the chemical environ-
ment afforded by the raw leachate was a hostile one which would not
permit the growth of activated sludge microorganisms.  It was concluded
from the data that ammonia toxicity was responsible for inhibiting the
activated sludge.  However, low ambient temperatures may have contri-
buted to these findings.  Consequently, during the Spring of 1977, Systems
3 and k will be reevaluated.          /

     During the coming months, it is proposed that increased emphasis
be placed on bench-scale testing including System 5.   As mentioned
above, this information will be used to develop kinetic and design cri-
teria and to optimize operational parameters.  The bulk of this work will
be focused on System  I  because the data collected indicate that treat-
ment effluent criteria can be readily reached with chemical/physical
treatment followed by activated sludge.

     The changes in the emphasis of the experimental program outlined
in the above paragraphs are reflected in Figure 8.   In this chart,
it is seen that bench-scale studies and operation of Systems 1 and 2
will continue for the next six months, and that Systems 3 and k wt11
be reevaluated during months eighteen through twenty-three.
                                      -56-

-------
      It  is  jpporent  that  there  is sufficient technical justification  for
extension of  the  project  period for a third year.  Overt3l!,  the  purpose
of  the demonstratton  project  is to show in a full-size plant  that cb^mi-
cal-physic.il-biologica! treatment of leachate is possible, to select  the
best  treatment sequence,  and  to develop sound treatment cost  data.

      The various operational  sequences of treatment have been put through
their initial tertir.g and it  appears that chemical-physical  followed  by
biological offers the best potential.  However,  because of the initial
startup period, we should take another look at the other alternatives.
Further, we have come to  recognize that leachate quantity and quality
transients are having a significant impact on the plant operation and,
consequently, on the treatment cost data.   GROWS has indicated that
they would consider  installation of an initial  equalizat'on  lagoon Lo
permit a more uniform input of leachate.   Whether or not they would
authorize such a  lagoon depends substantive1'/ o° tie decision with re-
gard  to a thi rd year.

     Based on our operating experience to date,  there are several factors
which we believe should be evaluated in a  third  year.   The results of  j
third study year would greatly enhance the quality of the final  results
of the demonstration project.   These factors are briefly outlined below.

     1.   By construction of the equalization lagoon, flow and quality
         characteristics would be smoothened,  thereby developing a quasi-
         steady state treatment process.   This effect would allow for a
         better definition of  the relationship between treatment cost
         and leachate quality.  The third  year may be used to separate
         the total power costs into the component parts:  raw leachate
         pumping,  aerators,  other treatment  requirements  and final
         effluent  pumping.

     2.   An extended evaluation of leachate  treatment  using the  process
         sequence  scheme which has the  most  potential  will  clearly
         indicate  impact on  treatment  cost of changes  in  quantity,
         quality and seasons.

     3.   Some bench  scale  studies  have  been  performed  during the  first
         two project years;  a  third  year would allow for  a full-sized
         plant assessment  of the pilot  plant results.

     ^.   A third year would  permit the  time  necessary  to  optimize plant
         operation,  using  the  selected  scheme, by developing techniques
         to maximize removal and minimize  operating  costs.

     5-   A third year would  allow  for gathering  of additional  informa-
         tion to refine  design criteria.

     6.   A' third year would  allow  for a full  scale  investigation  of  the
         potential for operating  the  plant to maximize  the  removal  of
                                         -57-

-------
specific contaminants, such as particjlar heavy metals, and to
minimize operating costs.  (i.e., pH adjustment based on metals
present).
                         -58-

-------
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                           V!U   REFERENCES

  1.   Remson,  I., A. A.  Fungarol i and A.W.  Lawrence.   "Water  Movement  in an
           Unsaturated  Sanitary Lancinn."  Proceedings A5CE,  Journal  of_
           the  Sani t.iry Cnq ; ^,,..j ; ng Division, 94. SA2(1968) .  '

  2.   Calvert,  C. "Contamination of Ground Water by  Impounded  Garbage
           Water".  Journal, of  the American Wa t e r Works Assocf at ion 2k,

  3-   Carpenter, L.V. and L.R. Setter.  "Some Notes on Sanitary  LandfPls".
           American Journal of Public Health 30, (1940).

  4.   University of Southern California.  Factors Controlling  Utilization
           of Sani tary  Landf i 1 1  Si tes.  F i n a 1 Report  to Pep  rtment of
           Heal th, Education and We i fare ,  National  i nst i tute of  Health.
           U.S. Public  Health  Service", Washington,  rCc~. Hl^T^

  5.   Longwell, Jr.   "The Water Pollution  Aspect of Refuse Disposal."
           Paper No. 6261 .   Inst i tut ion o_f_ Civil Enaineers Proceedings  8,
               24 (1957).                           "
 6.  Ministry of Housing and Local Government.  Pollution of Water by
          Tipped Refuse.  Her Majesty: Stationery Office, London  ( 1 % 1 ) .

 7.  Qasim, S.R.  Chemical  Characteristics of Seepage Water from  Simula-
          ted Landfills.  Ph.D.  Dissertation.  West Virginia University,
          Morgantown. (1965).

 8.  Andersen, R.J. and J.N. Dornbush.  Influence of Sanitary Landfill on
          Ground Water Quality.   Journal  American Water Works Association
          59, 4 (1967).

 9.  Hughes, G.M., R.A. Landon and R.N.  Farvolden.  Summa/ry of the Find-
   "      ' n9s on Sol ? d Waste Disposal Si tes J_n_ Northeastern ! 1 1 inoi s .
          Illinois State Geological  Survey, U^ana (1971).

10.  Steiner, R.L.  Chemical and Hydraulic Characteristics of Hilled
          Refuse.   pH.D. Thesis.  Drexel -Uni vers i ty ,  Philadelphia (1973).

11.  Weaver, L.   "Refuse Disposal, Its Significance".  RATSEC Technical
          Report W-61-S.  In Ground  Water Contamination.  Proceedings
          of a 1961 Symposium, pp. 104-1 0.  Robert A. Taft Sanitary
          Engineering Center, Cincinnati  (1961).

12.  Engineering Science, Inc.  Fi nal  Report .  I n-c i tu I nvest i gat ion of
          Gases Produced from Decomposing Refuse.  Publication No. 35-
          State Water Quality Control  Board.  'Sacramento, Cal.  (1967).

13-  Walker, W.H.   "Illinois Ground  Water Pollution".  Journal  American
          Water Works Assoc i at ion ( 1 969 / •


                                      -62-

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                           V!'.   REFERENCES

  1.   Remson,  I., A. A.  Funqaroli and A.W.  Lawrence.   "Water  Movement  in an
           Unsaturated  Sanitary Landfill."  Proceedings  ASCE,  Journal  of
           the  Sani t.iry Cnq ; ^,,..r ; ng Division, 9jt, SA2  (1968).

 2.   Calvert,  C. "Contamination of Ground Water by  Impounded  Garbage
           Water".  Journal of_ the American Wate*" Works  Associ at ion 2k ,

 3-   Carpenter, L.V. and L.R. Setter.  "Some Notes  on Sanitary  Landfills".
           American Journal of Public Health 30,
 4.  University of Southern California.  Factors Controlling Utilization
          of Sani tary Landf i 11 Si tes .   Fi nal Report _t£ Deo . rtTent  ojf
          Heal th, Education and We (fare, Nat iona1  ! n_s_*. i t'Jte of  Heal th.
          U.S. Public Health  Service,  Wash ; ngto-i . FTc^ ( \ 9637T

 5.  Longwell, Jr.   "The Water Pollutior Aspect of Refuse Disposal."
          Paper No. 6261 .   I nst i tut :on of Civil Engi neers Proceed ings  B_,
 6.  Ministry of Housing and Local Government.  Pollution of Water  by
          Tipped Refuse.  Her Majesty: Stationery Office, London  (1%1 ) .

 7.  Qasim, S.R.  Chemical Characteristics of Seepage Water from  Simula-
          ted Landfills.  Ph.D. Dissertation.  West Virginia University,
          Morgantown. (1965).

 8.  Andersen, R.J. and J.N. Dornbush.  Influence of Sanitary Landfill on
          Ground Water Quality.  Journal American Water Works Association
          59, * (1967).

 9.  Hughes, G.M., R.A. Landon and R.N. Farvolden.  Summa/ry of the  F i nd -
   "      ings on Sol id Waste Pi sposa^ Si tes in Northeastern 1 11 inoi s .
          Illinois State Geological  Survey, 'Jrbaria  (1970 •

10.  Steiner, R.L.  Chemical and  Hydraulic Characteristics of Milled
          Refuse.   pH.D. Thesis.   Drexel -Uni vers i ty , Philadelphia (1973).

11.  Weaver, L.  "Peruse Disposal, Its Significance".  RATSEC Technical
          Report W-61-S.  In Ground  Water Contamination.  Proceedings
          of a 196? Symposium, pp. 10^-10.  Robert A. Taft Sanitary
          Engineering Center, Cincinnati (1961).

12.  Engineering Science, Inc.  Fi nal  Report .  ln-ritu Investigation of
          Gases Produced from Decomposing Refuse.  Publication No.  35-
          State Water Quality Control  Board.  Sacramento, Cal. (1967)-

13.  Walker, W.H.   "Illinois Ground  Water Pollution".  Journal American
          Water Works Associat ion (1969).


                                      -62-

-------

 I'*.   Roessler,  B.  "Beeinf 1 uss inq des Grundwasser durch Mull  und
          Schuttablayerungen".  '. ,~i Wasser  18, 43  (1350-50-

 15-   Lang, A.   "Pollution of Water Supplies, Especi-aHy Underground
          Streams".  Gesundh Technical Sladtehyg 2&.  (1932).

 16.   Chian, E.S.K. and F.B. DeWalle.  "Sanitary Landfill Leachates
          and their Treatment".  Proceed! ngs ASCE, Journa* of the
          Envi ronmental Eng ineer ing Div i s ion !02 , EE2 , A ] 1 -3 ' ^
 17-  R. J. Schoenberger, A. A. FungaroH , R. L. Steiner and S. Zison.
          Treatability of Leachate from Sanitary Landfills.  Mid-Atlantic
          Industrial Waste Conference, University of Delaware, Newark
          (1971).

 18.  J. W. Patterson and R.A. Minear.  Wastewater Treatment Technology.
          Prepared for Illinois Institute of Environmental Quality.
          279 pp.  Published by NT|S, Springfield, Va.  PB-204 521.
          (1971).

 19.  American Public Health Association, American Water Works Associa-
          tion and Water Pollution Control Federation.  Standard Methods
          for the Examination of Water and Wastewater.  Hth Edition.
          Published by APHA, New York (1976).

20.  American Society for Testing and Materials.  Standards.  Part 23
          (1972).

21.  U. S. Environmental  Protection Agency.   Manual  of Methods for Chem-
          ical Analysis of Water and Wastes, 2nd Edition.   EPA-625/6-7^-
          003 0971*).

22.  Analytical  Procedures for Chemical  Pollutants,  Pollution of Sub-
          surface Water by Sanitary Landfills".   Research  grant EP-000162,
          NTIS,  Springfield, Virginia.

23-  LaGrega, M.D. and J.D.  Keenan.  "Equalization of Sewage Flows".
          Journal Water Pollution Control  Federation (197*0-
                                    -63-

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             APPENDIX
LEACHATE TREATMENT PLANT CF2RATION
      AND MAINTENANCE ROUTINE
             -64-

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     Although the  profession has considerable experience  in  the
operation  of  chemical/physical and biological treatment processes,
there  is no  literature  relative to the operat:on of  leachate  treat-
ment plants.   It  is  for  this reason that the following section has
been prepared.   It  is hoped that this  information will prove  valuable
in  the  operation of  the  leachate treatment plants that are sure  to
fo11ow.

                         CHEMICAL/PHYSICAL UNITS

Lime Treatment

     The lime handling equipment receives routine operator attention
for the fallowing:   twice daily backwash of lime pumps and three  times
daily addition of  lime to the hopper.   The lime slurry lines  are
checked daily where  they enter the clarifier to ensure the free  ilow
of  lime slurry.  Lime is received about twice per week in shipments of
two  pallets   which are unloaded and the sacks stored.  M.-rnt2nance of
the lime pumps is carried out at weekly intervals.  This consists of
removing all  lines from  the pump, draining them and  looking for blockage.
The piping is backwashed for about five minutes, and any lime which
has settle^ out in the  lime slurry bin is broken up and dispersed.

     Additional maintenance for the lime system is performed  routinely
at monthly intervals.  The lime slurry bin is drained completely using
the barrel transfer  pump.  This has to be done three or more  t'mes to
remove most of the material.  Any additional  residue is scooped out.
Hardened lime .is chipped and scraped away from the sides,  pipes, and
mixer blade.  'Both lime  pufnps are disconnected,  a!'  pipes to  the  lime
bin are removed, cleaned and backwashed.   Ordinarily, some pipes are
replaced and  new fittings are often needed.   Lime is chipped out of
the pump impellers which have a tendency to work loose, and therefore
need tightening.  Lime slurry pipes from the  pumps to the clarifier
generally need to be replaced every month due to lime coating resulting
in excessive  hydraulic resistance.   The float valve  in the lime slurry
bin must be completely cleaned and lubricated,  and it must be replaced
frequently.

Clarifier

    The clarifier in the chemical/physical  section has been relatively
maintenance-free.  On a  routine basis  at  monthly intervals, it is
necessary to  remove  excess sludge.   This  is  done by drawing down the
clarifier about 2,000 gal. in order to bring  the level below  the bottom
of the center rings.   The rings are washed out,  and  the thick hardened
material is chipped  away from the nixer blade.   The  clarifier screw
                                  -65-

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gear box and  the clarifier mixer are checked monthly for oi1 .  At weekly
 intervals,  the one fitting on the c'arifier mixe*" and three on the
clarifier drive are greased.  Genera1Jy, 500 gal of primary clarifier
sludge are wasted daily.  Sludge is either pumped cvrect'y  into a tank
truck or into the sludge holding tank.   fn the Batter case-,  !t is sub-
sequently air lifted or pumped to the tank truck.  The truck  is filled
and the sludge returned to the landfill approximate?y two or  three
times per week.  Tnis includes any sludge wasted from the biological
uni ts.

Lagoon

     The flow from the lagoon to the biolonical unit is checked daily
and is usually adjusted because or influent flow changes.  The level
in the lagoon increases rad'cal'y the day after 3 h^avy rain.  Varia-
tions in the flow rate to the biological u-i"t ore made on the basis of
maintaining the flow as constant as possible without permitting the
lagoon to empty or overflow.

Acidi ficat ion

     Acid solutions are prepared on an  as needed basis.   The general
procedure is to add sulfuric acid to a  half tank of water by pumping
from the acid barrel  with a transfer pump using a one inch hose.   At
the present time, the sulfuric acid is  added only as needed.  The phos-
phoric acid solution  is prepared by the addition of two gallons to a
tank of water, and this lasts for two days.  The acid pumo is checked
and oiled monthly.  The check valves are usually replaced at this time.
The acid tank is drained with the barrel transfer pump and any sediment
is swept out.  The tubing and back pressure valve are also inspected.

                            BIOLOGICAL  UNITS

Aeration Tanks

     The froth sprav  nozzles are observed daily and cleaned as necessary.
It is  necessary to check .the return sludge line and the  scum line.  These
air lifts are very sensitive to variations in the air pressure, and they
are usually off if the blower has previously shut down.   The blowers are
checked periodically  and,  at monthly intervals, they are greased and
oiled,  and the condition of the belts is noted.

Secondary Clarifier

     The surface of the clarifier is cleaned as needed.   This is
usually at weekly intervals.  The floating material concentrates  between
the weirs and the effluent baffles from which it must be removed  before
it builds up,overflows the weir and degrades the efrluent.  Sludge from
the biological unit is wasted as it becomes necessary.


                                     -66-

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                            DATA COLLECTION

     Each day at noon, the operator ta'-es meter readings of electricity
consumed, volume of effluent treated and volume or influent pumped from
each manhole.  The calibration of these readinqs is occasionally re-
checked as discrepancies have been noted.  Samples are collected for
the daily tests: chemical oxygen demand, dissolved solids,  suspended
solids, pH, settleable solids, total solids,  volatile suspended colids,
dissolved oxygen and temperature.  These samples are colloctc^ f^om the
raw leachate, clarifier effluent, lagoon, mixed liquor and final efflu-
ent.  Weekly samples are obtained from the same set of sampling points,
and are analyzed, in addition ?-o the daily tests,  for the ^o''owing:  5
day biochemical  oxygen demand, sjifate, ortho-phospHate, ch'oride, alka-
linity, ammonia nitrogen, organ;c nitrogen, kje'dah'  Ktrogen, hardness,
sodium, potassium,  magnesium,  calcium, and the  • .?.vy metals cadmium,
chromium, copper, iron, lead,  mercury, nickel, and zinc.  The  atomic
absorption spectrometer is used for the heavy metals, and it must be
dismantled and cleaned after each use.

                          GENERAL MAINTENANCE

     This includes  general  cleaning of the laboratory, plant and grounds,
repair of leaks, etc.   There are other pumps  not mentioned above which
need grease and  oil  on a routine schedule.  These  pumps  are for sodium
hydroxide and chlorine, and for the final  effluent.   In  addition, thj
various equipment in the laboratory must be properly  maintained.
ya!541
SW-91d
                                    -67-         «v
                                                2JU

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