PB85-196798
Determination of Toxic
Chemicals in Effluent from
Household Septic Tanks
Washington Univ.* Seattle
Prepared for
Environmental Protection Agency, Cincinnati, OH
Apr 85
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EPA/600/2-85/050
April 1985
DETERMINATION OF TOXIC CHEMICALS IN PBbb- b 98
EFFLUENT FROM HOUSEHOLD SEPTIC TANKS
by
Foppe B. DeWalle
David Kalman
Donald Norman
John Sung
Department of Environmental Health
University of Washington
Seattle, Washington 98195
Gary Plews
Department of Social and Health Services
Olympia, Washington 98504
Cooperative Agreement
Grant No. R 806102
Project Officer
Ronald F. Lewis
Wastewater Research Division
Water Engineering Research Laboratory
Cincinnati, OH 45268
WATER ENGINEERING RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OH 45268
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TECHNICAL REPORT DATA
(Pkase read/uUfiictioiit on the ttvtnc before coinptcrtiif
I. REPORT NO.
EPA/600/2-85/050
2.
3. RECIPIENT'S ACCESSION-NO.
PBS 5 196798 /AS
4. TITLE AND SUBTITLE
DETERMINATION OF TOXIC CHEMICALS IN EFFLUENT FROM
HOUSEHOLD SEPTIC TANKS
5. REPORT DATE
April 1985
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Foppe B DeWalle, David A. Kalman, Donald Norman,
John Sung, and Gary Plews
«. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Deaprtment of Environmental Health
University of Washington
Seattle, Washington 98195
10. PROGRAM ELi.ME.NT NO.
11, CONTRACT/GSA.VT NO.
R806102
12. SPONSORING AGENCY NAME AND ADDRESS
Water Engineering Research Laboratory -
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
- Cin. OH
13. TYPE OF RE?CRT AND PERIOD COVERED
Final 10/78 - 9/82
4. SPONSORING ACeNCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Project Officer: Ronald F. Lewis
(513) 684-7644
16. ASSTRACT
The report study evaluated the presence of volatile organics in raw
domestic sewage generated In a subdivision and treated by a large 5-year-
old community septic tank that had recently been cleaned by having the
solids removed by pumping just prior to this study. Analysis showed the
presence of priority pollutants in the raw sewage. Essentially no remov?I
of these compounds occurred during the 2-day detention in the septic
tank. The priority pollutants generally showed higher levels during the
weekend, probably reflecting leisure activities and use of related
chemicals (paint thinners, grease removers, toilet bowl cleaners, etc.),
than during the week days. Most of the other volatile compounds were
hydrocarbons, and their removal by the septic tank generally decreased
with increasing molecular weight. Several organic sulfur compounds
showed substantial increase as a result of anaerobic degradation processes
in the septic tank.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS jc. COSATI Field/Croup
3. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY C'.ASS (Tint Report)
Unclassified
21. NO. Of I'AGcS
34
20. SECURITY CLASS iTIiit page/
Unclassified
::. PRICE
EPA Form 2220-1 (»-73)
i
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DISCLAIMER
Although the information described in this document has been funded vnolly
or in part by the United States Environmental Protection Agency through
assistance agreement number R-806102 to the University of Washington, it
has not been subjected to the Agency's required peer and administrative
review and therefore does not necessarily reflect the views of the Agency
and no official endorsement should be inferred.
ii
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FOREWORD
The U. S. Environmental Protection Agency is charged by Congress with
protecting the Nation's land, air, and water systems. Under a mandate of
national environmental laws, the agency strives to formulate and imple-
ment actions leading to a compatible balance between human activities and
the ability of natural systems to support and nurture life. The Clean
Water Act, the Safe Drinking Water Act, and the Toxics Substances Control
Act are three of the major congressional laws that provide the framework
for restoring and maintaining the integrity of our Nation's water, for
preserving and enhancing the water we drink, and for protecting the
environment from toxic substances. These laws direct the EPA to perform
research to define our environmental problems, measure the impacts, and
search for solutions.
The Water Engineering Research Laboratory is that component of EPA's
Research and Development program concerned with preventing, treating, and
managing municipal and industrial wastewater discharges; establishing
practices to control and remove contaminants from drinking water and to
prevent its deterioration during storage and distribution; and assessing
the nature and controllability of releases of toxic substances to the
air, water, and land from manufacturing processes and subsequent product
uses. This publication is one of the products of that research and
provides a vital communication link between the researcher and tr.e user
community.
The purpose of this project was to measure the presence of volatile
priority pollutants in domestic sewage as it enters a large comncaity
septic tank system and to evaluate the removal of these compounds in the
anaerobic septic tank by analyzing effluent samples collected froa the
distribution box as well as the sludge and scum found in the septic tank.
This report is to bring this information to the attention of design
engineers and to researchers conducting work on the fate of priority
pollutants.
Francis T. Mayo, Director
Water Engineering Research Laboratory
iii
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ABSTRACT
The present study evaluated the presence of volatile organics in raw do-
mestic sewage generated in a subdivision and treated by a large 5-year-old
community septic tank that had recently been cleaned by having the solids
removed by pumping just prior to this study. Analysis showed the presence
or priority pollutants in the raw sewage. Essentially no removal of these
compounds occurred during the 2-day detention in the septic tank. The
priority pollutants generally showed higher levels during the week end,
probably reflecting leisure activities and use of related chemicals (paint
thinners, grease removers, toilet bowl cleaners, etc.) than during the week
days. Most of the other volatile compounds were hydrocarbons, and their
removal by the septic tank generally decreased with increasing molecular
weight. Several organosulfur compounds showed substantial increase as a
result of anaerobic degradation processes in the septic tank.
This report was sbumitted in fulfillment of cooperative agreement
R-806102 by the University of Washington, under sponsorship of the U.S.
Environmental Protection Agency.
IV
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CONTENTS
Disclaimer ii
Foreword iii
Abstract iv
Concents ............................ v
Tables and Figures vi
1. Introduction 1
Materials and Methods 3
Results and Discussion 5
Flow measurements 5
Presence of trace organics 6
Conclusion 10
References 11
Tables and Figures 12
Appendix A. Daily analyses .... 23
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TABLES AND FIGURES
Number
1
2
Number
2
3
4
5
6
7
8
9
10
11
TABLES
Page
Occurrence of Volatlles in Septic Tank 12
Forward Search of Volatile Compounds in Septic Tank
(Sunday) 13
FIGURES
Page
Subdivision with community septic tank evaluated
in the present study 14
Community septic tank evaluated in the present study. . 14
Frequency distribution of water usage 15
Flow pattern at septic tank system 16
Normal frequency distribution of surrogate recovery . . 17
Daily variation of toluene 18
Daily variation of dichloromethane 18
Daily variation of chloroform 19
Percentage of samples equal to or less than indicated
concentration (benzene, toluene, ethylbenzene) .... 19
Percentage of samples equal to or less than indicated
concentration (dichloromethane, chloroform) 20
Percentage of samples equal to or less than indicated
concentration (bromomethane, tetrachloethene) 21
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FIGURES
Number Page
12 Reconstructed total ton current of the volatile organics
in the influent and effluent of the septic tank .... 21
13 Attenuation of volatile compounds during septic tank
treatment 22
14 Attenuation of volatile hydrocarbons during septic tank
treatment 22
vii
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Introduction
On-site disposal of sewage is widely practiced in rural
areas and urban fringes. However, it has received relatively
little attention from1regulatory agencies or research institutes,
For example, little comprehensive information is currently
available to document successes and failures of on-site disposal
systems and the resulting health implications. The 1970 census
noted 403,910 septic tanks or cesspools and 14,464 other
individual systems such as aerobic or ponds in the State of
Washington, representing 34.7% of all housing units (Bureau of
the Census, 1972). A current survey in the State of Washington
also indicates the presence of more than 500 large on-site
systems serving hospitals, schools, restaurants and subdivisions
(DeWalle, 1981). As the septic tank effluent is directly
returned to the soil through infiltration in the subsurface
drainfield, considerable public health concern exists in regard
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to groundwater contamination and pollution of drinking water
wells. A recent study showed such widespread contamination in
major parts of central Pierce County south of Tacoma (DeWalle and
Schaff, 1980).
The development of the septic tank is credited to John Louis
Mouras who constructed a masonry tank in which sewage and rain-
water from a dwelling in Vesoul, France, were collected before
passing to a cesspool. Absence of solids after twelve years of
operation led to its patent in 1881. The first household septic
tank in the U.S. was constructed by Edward Philbrick of Boston,
Massachusetts, in 1883, and consisted of two round chamber tanks
(Metcalf, 1901). Various types, shapes and arrangements have
been used since the earliest units with detention times ranging
from 2 hours in so-called "freshwater clarification tanks" in
Germany, to 20 days in large underground tanks in Poland, and
usually 24 hours in U.S. systems. Walker and Driftmeier (1929)
noted decreasing solids removals when detention times increased
from 35 to 92' hours. Weibel e_t al. (1949) noted a leveling off
of the suspended solids (SS) removal beyond a detention time of
half a day, while the biochemical oxygen demand (BOD) removal
still showed stabilization after one day. The low suspended
solids removal observed during the summer represents a typical
unloading of the sludge in which the generated gases carry the
solids out of the tank. Additional factors shown to be of
importance are sufficient depth to allow for sludge accumulation,
compartmentalization to prevent short circuiting and use of
baffles to reduce sludge carry over.
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In previously published studies only the efficiency of the
septic tank with respect to BOD, SS and grease removal was
evaluated while the trace organics present in domestic sewage and
in septic tank effluent were not measured. The present study was
conducted to collect such data. It was the purpose of the study
to measure the presence of volatile priority pollutants in
domestic sewage as it enters a large community septic tank
system. The study also evaluated the removal of these compounds
in the anaerobic septic tank by analyzing effluent samples
collected from the distribution box.
Materials and Methods
A community septic tank serving 97 homes in a subdivision
(Oakbrook 6) located south of Tacoma, Pierce County, Washington,
was used for this study. The homes are located on four streets
served by a 200 mm (8 inch) gravity sewer which discharges into a
wetwell (Figure 1). A 10.1 L/s (160 gpm) submersible centrifugal
pump transports the waste to the septic tank. The unit contains
84,935 litres (22,440 gallons) liquid volume in the first
compartment and 42,468 litres (11,220 gallons) in the second
compartment (Figure 2). The raw sewage sample was collected
through the manhole from the inlet-T before the sewage mixed with
the contents of the first compartment. The effluent sample was
collected from the distribution box located 4.57 meters (15 feet)
downstream from the effluent-T.
The sewage was collected using an all glass/teflon custom-
made sampler. The sewage was drawn by suction through a 0.5 inch
3
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teflon intake line using a 100 ml glass syringe. When the
syringe was in its drawn position, a teflon solenoid va.lve closed
the intake line and opened the discharge line. When tf(e syringe
content was subsequently displaced, it flowed through the dis-
charge line to a collection device with a floating plunger to
prevent losses of volatile organics. The septic tank effluent
was collected using a similar sampler drawing from below the
liquid surface in the distribution box. The samples were col-
lected as 24 hour composites during a 7-day continuous period.
The volatile organics were removed from the aqueous sample
with a purge and trap method (Kalman, et al., 1980. A modified
Hewlett/Packard 7675A Purge and Trap Sampler was used to purge
10 ml of liquid with nitrogen gas at a rate of 20 ml/min. The
volatile organics that were stripped from the liquid were subse-
quently absorbed when the nitrogen passed through a Tenax GC
trap. The trap was subsequently heated and the volatile organics
were back flushed and trapped in the initial 0.5 meter portion of
a 30 m fused silica WCOT column with SE-54, stationary phase
(J & W Scientific) chilled by liquid nitrogen. After removal of
the cryotrap and flash heating of the column, the volatiles were
separated in the gas chromatograph (Model (3840A Hewlett/Packard,
Palo Alto, California) and detected by mass spectrometry
(Finnigan 4023, Finnigan, Sunnyvale.- California). A computer
library system containing spectra of 30,000 compounds was used
for a spectral comparison with each detected compound.
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Results and Discussion
a. Flow measurements
Flow data were obtained both from the water usage records of
the Lakewood Water District Company and from measurements in the
wetwell. The water usage data show a baseline of 58.7 litres per
minute (15.5 gallons per minute), which usage triples to 219.5
litres per minute (58 gpra) during the summer months due to
extensive yard usage. The frequency distribution of the flow
rates (Figure 3) shows several maxima corresponding to usage in a
household with 1, 2, 3, 4, 5, 6, or 7 persons respectively. The
median household, having 3.2 persons, has a usage of 897 litres
per dav (237 gallons/day). The usage ranges from 329.3 litres
per person per day (87 gallons per person per day) for a one-
person household to 242.2 litres per person per day (64 gallons
per person per day) for a seven-person household.
The flow measurement at the wetwell consisted of determining
the interval between sequenced pump switch-on times. By knowing
the holdup volume in the wetwell the flow rate during the day can
be calculated. This resulted in an average calculated flow of
44.7 litres per minute (11.8 gpm) which is 24% less than calcu-
lated from the usage data, indicating that about a quarter of the
used water does not reach the septic tank and is lost through
evaporation (clothes dryer, plant evapotranspiration, sewer leaks,
etc.). The highest discharge rates and highest standard devi-
ation were noted around 9 p.m. (Figure 4).
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b. Presence of Trace Organics
The efficiency of the volatile organic analysis (VGA) using
the purge and trap unit was evaluated using surrogate compounds
spiked at 20 ppb in the liquid before purging. The results show
a median recovery of 91% for bromochloromethane, 90% for
1,4-dichlorobutane, and 82% for Dg-benzene (Figure 5). The
standard deviations, however, were substantial at this low con-
centration level.
The organics were measured in the samples during an
intensive week long monitoring followed by six additional
samplings, the last one occurring on January 23, 1982. The
results are summarized in Table 1 and indicate that dichloro-
methane was found in all samples, followed by toluene in fre-
quency of detection. These two compounds were also found in the
water collected from the 125-foot deep monitoring well located
adjacent to the drainfield. The analysis during the week long
monitoring was initiated on Monday, September 22, and was ter-
minated on Sunday, September 28, 1980. The volatile organic
fraction typically contained 40 to 50 compounds at a
concentration > 1 ppb. However, only 5 were identified as
priority pollutants. Appendix A has the daily data.
Toluene was the most prevalent among the priority pollu-
tants, at an average concentration of 34.6 -vg/L in the raw
sewage, and 38.8 Mg/L in the effluent (Figure 6). The toluene,
originating from cleaning solvents and paint thinners, reached
its maximum concentration of 47.8 pg/L in the influent-on Friday,
while the effluent reached a maximum of 56.9 ug /L on Sunday. The
6
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shift in the maximum toluene concentration by 2 days may be a
result of the detention time which was estimated at approximately
2 days.
Dichloromethane likely originating from chlorinated tapwater
was present in the next highest concentration (Figure 7) and also
showed its highest level on Sunday. However, no lag was detected
between effluent and influent. Chloroform (Figure 8) showed its
maximum concentraion in the influent on Saturday, while the
effluent showed a second maximum on Sunday, representing a
one-day shift. Tetrachloroethene was generally low during the
week but reached a maximum on Monday. Benzene was detected only
on Wednesday.
A log-normal frequency distribution graph of the aromatic
compounds (Figure 9) shows the presence of benzene only in the
scum and sludge layer. Although benzene was not detected in the
influent, it was detected on two occasions in th effluent,
possibly due to discharge of solids from the scum or sludge
layer. Toluene showed no removal in the septic tank and very
little accumulation in the scum and sludge layer. Low removals
were also noted for the chlorinated compounds (Figures 10, 11).
The generally low removals of the volatile organics is fur-
ther reflected in Figure 12, showing the reconstructed ion cur-
rent of all the compounds detected in this fraction. A tabula-
tion of the 48 compounds (Table 2) shows that the majority are
hydrocarbons including both aliphatic and cyclic structures.
Several compounds reflect the presence of anaerobic degradation
processes occurring in the sewerline or septic tank. High
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concentrations were noted for 2-propanone, 2-ethyl-4-methyl-
1-pentanol and 4-methyl-2-propyl-l-pentanol/ all likely origi-
nating from anaerobic decomposition processes. Large increases
were also noted for several biogenic organosulfur compounds such
as carbon disulfide, methanethiol (methylmercaptan), dimethyl
disulfide and dimethyl trisulfide. The largest increase was
noted for methanethiol with small increases noted with larger
molecular weight compounds probably reflecting the greater
difficulty for bacteria to generate these larger compounds. This
trend for alcohols, aldehydes, and organosulfur compounds is
reflected in Figure 13 where the effluent/influent ratio of each
compound generally decreases with increasing retention during the
chromatographic separation. A larger retention time generally
reflects an increasing molecular weight. The low molecular
weight alkylated benzenes show a significant removal, probably
due to biodegradation, but the results show no removal for higher
molecular weight compounds. The hydrocarbons (Figure 14) showed
the highest removals at intermediate molecular weight and lower
removals at larger molecular weights, probably due to reduced
volatilization. The increase noted for several of the low
molecular weight hydrocarbons may be a result of their formation
as intermediates in the breakdown of larger molecular weight
hydrocarbons.
The present study has important implications for assessing
the environmental impact of septic tanks. As little removal of
the volatile priority pollutants.is observed, these compounds
will be discharged through the subsurface drainfield and may
8
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enter the groundwater. Volatilization is a removal mechanism in
the septic tank, tmtc this mechanism will not be effective in the
presence of a thick scum layer and during subsurface drainage and
migration. Some biodegradation of several organosulfurs and
hydrocarbons will likely occur during soil migration, especially
since aerobic conditions generally prevail. The chlorinated
organics and most of the branched or cyclic hydrocarbons,
however, are less likely to be degraded by bacterial action, and
are expected to migrate considerable distances in the soil. A
related study by DeWalle and Chian (1981) noted substantial
migration of low molecular weight chlorinated solvents away from
a landfill in Delaware.
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Conclusion
The present study evaluated the presence of volatile
organics in raw domestic sewage generated in a subdivision and
treated by a large 5-year-old community septic tank that had
recently been cleaned by having the solids removed by pumping
just prior to this study. Analysis showed the presence of
priority pollutants in the raw sewage which compounds showed
essentially no removal during the 2-day detention in the septic
tank. The priority pollutants generally showed higher levels in
the week end, probably reflecting leisure activities and use of
related chemicals (paint thinners, grease removers, toilet bowl
cleaners, etc.). Most of the other volatile compounds were
hydrocarbons, and their removal by the septic tank generally
decreased with increasing molecular weight. Several organosulfur
compounds showed substantial increase as a result of anaerobic
degradation processes in the septic tank.
10
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REFERENCES
Bureau of the Census. Housing characteristics for states,
cities and counties, Volume I, Part 49. Washington. 45
Government Printing Office, Washington, D.C., 1972.
DeWalle, F. B. Failure analysis of large septic tank
systems. Jour. Envir. Engin. Div. ASCE 107:229, 1981.
DeWalle, F. B., and Schaff, R. M. Groundwater pollution by
septic tank drainfields. Jour. Envir. Engin. Div. ASCE
K)6/.631, 1980.
DeWalle, F. B., and Chian, E. S. K. Detection of trace
organics in well water near a solid waste landfill. Jour.
Amer. Water Works Assoc. 7_3:206, 1981.
Kalman, D. A., Dills R., Perera C., and DeWalle, F. On
column cryogenic trapping of sorbed organics for
determination by capillary gas chromatography. Anal.
Chemistry 52:1992, 1980.
Metcalf, L. The antecedents of the septic tank. Trans.
Amer. Soc. Civil Engin. 5_, 1901.
Walker, H. B., and Driftmeier, R. H. Studies of the septic
tank method of sewage disposal for isolated homes. Agr.
Engin. 10^:256, 1929.
Weibel, S. R., e_t al. Studies on household sewage disposal
systems, Vol. I. Public Health Service, Cincinnati, 1949.
11
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Table 1. Occurrence of Volatiles in Septic Tank
Compound
Dichlorone thane
Chloroform
Trichlorofluorcme thane
Bromcme thane
1,1, 2- tr ichloroethane
Trichloroe thane
1,1, 1-tr ichloroethane
1 , 3-dichloropropene
Benzene
Chlorobenzene
Toluene
Ethylbenzene
Tap
n=2
100%
0
0
0
0
0
0
0
0
0
0
0
Influent
n=13
100%
62
0
0
0
8
0
8
0
0
85
15
Effluent
n=13
100%
62
0
15
8
8
8
0
15
0
85
23
Scun
n=2
100%
0
50
100
8
50
0
0
100
0
50
100
Sludge
n=2
100%
0
0
50
0
0
0
0
50
50
0
100
Well
n=l
100%
0
0
0
0
0
0
0
0
0
100
0
12
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Table 2. Forward Search of Volatile Conpounds in
Septic Tank (Sunday)
Volatile Compounds (rcg/L) Scan Influent Scan Effluent
Methane, dichlorcdifluoro 1380 0.64 — < 0.7
Methanethiol — < 0.7 1395 128
2-Propanone 1407 18.2 1410 70.3
Methane, thiobis 1415 23.0 1418 84.4
Unknown hydrocarbon 1419 2.0 1421 4.2
Carbon disulfide + dichloromethane 1422 4.2 1424 10.0
C? hydrocarbon 1536 13.0 1527 13.6
H6xane, 3-methyl 1558 8.1 — < 0.7
Heptane 1612 6.2 — < 0.7
Disulfide, dimethyl 1754 11.6 1729 29.7
Benzene, methyl 1842 74.4 1825 16.7
Hexane, 2,5-dimethyl 1843 14.9 — < 0.7
Heptane, 3-methyl 1875 5.3 — < 0.7
Cyclohexane, 1,3-dimethyl, cis 1883 5.3 — < 0.7
Cyclohexane, 1,3-dimethyl, trans 1890 1.2 — < 0.7
Cyclohexane, l-ethyl-2-methyl 1971 1.0 — < 0.7
Heptane, 2.4-dimethyl 2009 15.3 — < 0.7
CIQ cyclic hydrocarbon — < 0.7 2770 3.3
PeKtane, 2,2,3,4-tetratvethyl 2947 9.7 — < 0.7
Trisulfide, dimethyl 2960 11.4 2941 12.7
Heptane, 6,6-dimethyl-2-methylene 2997 6.2 — < 0.7
Hexane, 2,2,5,5-tetramethyl 3000 8.0 — < 0.7
Branched C,0 hydrocarbon 3044 3.7 — < 0.7
Nonene, 4,eVs-trimethyl 3074 3.4 — < 0.7
Hexane, 3,3,4-trimethyl 3091 3.2 — < 0.7
Hexane, 2,4-dimethyl 3124 8.3 — < 0.7
Benzene, 1,4-dichloro 3149 16.7 3134 11.5
Pentane, 2,2,3-trimethyl 3157 2.5 — < 0.7
C,0 cyclic hydrocarbon 3179 7.2 3168 25.1
Benzene, l-methyl-4 (1-methylethyl) 3211 15.4 3205 71.6
Heptane, 2,2,4,6,6-pentamethyl 3221 17.1 3212 7.2
Cyclohexane, l-methyl-4-(l-methylethenyl) 3229 126 3221 107
C1n hydrocarbon " 3238 3.6 — < 0.7
Hexane, 2,2,5-trimethyl 3240 7.2 3231 15.5
Hexane, 3,3-dimethyl 3252 38.7 3242 21.7
Hexane, 2,2,3-triroethyl 3326 45.8 3318 24.7
1,4-cyclonexadiene,
l-methyl-4 (1-methylethyl) 3346 3.9 — < 0.7
Butane 2,2,3-trimethyl 3349 3.9 — < 0.7
1-pentanol, 2-ethyl-4-methyl 3367 21.2 3362 13.6
Pentane, 2,3,4-trimethyl 3408 11.9 3402 7.6
Pentane, 2,2,4,4-tetramethyl 3415 4.0 3410 1.8
Cyclohexane,1-methy1-4-(1-methylethylidene 3453 9.2 3449 15.7
1 pentanol, 4-methyl-2-propyl 3500 13.5 3497 10.0
Hexane 2,2,3-trimethyl 3583 5.9 3579 3.4
Cyclonexane (1-methylethyl) — < 0.7 3606 1.9
Bicycloneptane 3,7,7-triraethyl 3650 5.3 3652 41.6
Heptane, 5-ethyl-2-methyl 3717 5.7 3714 37.7
Benzene, 1,2,3-trichloro — < 0.7 3745 2.7
Total 623 793
13
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RtSERVt
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RESERVE
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Figure I. Subdivision with community septic tank evaluated in
the present study.
(To provide the reader with
complete information, these
reduced engineering drawings are
Included. These are the best
copies available; we regret that
portions are undecipherable.)
\
I. i
f?V
FOR 97RESIOEKCES
48 HOUR DETENTION TIME
.LK
•':. T
... LJ
140 GALLONS)
I ME
42.
("
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OF KS1DCNCES AT GIVEN RCURATE
NEDIAN FLOW 897 LITRES/HOUSE.
£237 GALLON/HOUSE.DAY)
1 PERSON - 329 LITRES/PERSON.DAY
(87 GALlOtl/PERSON.OAY)
2 PERSONS -
~306 LITRES/PERSON.DAY
' (81 GALLON/PERSON.DAY)
-_3 PERSONS -
284 LITRES/PERSON.DAY
(75 GALLON/PERSON.DAY)
_ 4 PERSOKS-
tTRES/PERSON.OAY
5 PERSONS- (» WU-ON/PERSON.DAY)
253 LITRES/PERSON.DAY
(67 GALLON/PERSON.DAY)
-6 PERSONS-250 LITRES/PERSON.DAY
(U GALLON/PERSON.DAY)
i -*-7 PERSONS-242 LITRES/PERSON.DAY
(64 GALLON/PERSON.DAY)
4.4X OF HOUSEHOLDS 1893-4436 LITRES /DAY (SCO - 1172 GALLONS PER DAY)
Figure 3. Frequency distribution of water usage.
15
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100
AVERAGE OF 8 DAILY MtASUKKNTS
S SO
5
a
«T«LL MEASUREMENT 44.7 LPK (11.8 GPM)
WATER METER READING 58.7 LPM 05.s GPM)
UNACCOUNTED 24J
20
10
NOON
Tt« OF DAY
12 MIDNIGHT
Figure 4. Flow pattern at septic tank system.
16
-------
zoo
150
£
UJ
S
100
SO
JO U6/L SWING UYU
O BWWOiLOROCTXAJtt
A M-OICHIOROBUTAM
O 06-BEKZEKE
I
I
I
J 10 JO 50 70 90 98
PERC£NTAG£ OF SAMPLES WITH LESS THAN CORRESPONDING RECOVERY
Figure 5. Normal frequency distribution of surrogate recovery
17
-------
sc
40
10
TOLUENE
O RAW SEWAGE
A SEPTIC TANK EFFLUENT
1
Non
2
Tue
3
Ued
4
Thurj
5
Frl
7
Sun
Figure 6. Daily variation of toluene.
O RAW SEWAGE
SEPTIC TANK EFFLUENT
Non Tut Ued Thur
Sun
Figure 7. Daily variation of dichlororaethane,
18
-------
CHlOKOftXW
O «AU SUAGE
SEPTIC TAHJC EFRUDIT
Sun
(ton Tut «eO Thurs
Figure 8. Daily variation of chloroform.
BEHZENE
1000
100
3 '"
s
5
»—
K
UJ
^** 10
§ '
0.1 -
0.01
TOLUENE
O TAP (UEU HATER)
O St'TIC TANK IHFLUENT
A EFFLUEUT
A SCUM LAYER
• SLUDGE
D ORAINFIELO WELL
ETHYLS EXZENE
20
SO
80
95 S
20
SO
80
9S S
20
SO
80
Figure 9. Percentage of samples equal to or less than indicated
concentration.
19
-------
s
i
t~
§
1000 —
100
10
1.0
0.1
0.01
D1OU.OKWETHANC
CHLOftOFOW
• TAP (UULUATER)
O SEPTIC TAtIK IKFLUEKT
& EFFLUENT
A SCUM
• SLUDGE
D DRMNFIELO WELL
5 ZO so 80 95 5 20 SO 80 95
Figure 10. Percentage of samples equal to or less than indicated
concentration.
20
-------
1000
100
10
§
i
X
UJ
g 1.0
0.1
0.01
tHONONCTHMtf
TETRACH.OHOETHENE
• TAP {WELL HATER)
O SEPTIC TAX* INFLUENT
A EFFLUENT
A SO* LAYER
• SLUDGE
Q DRAINFIELD HELL
80
95 S
SO
80
Figure 11. Percentage of samples equal to or less than indicated
concentration.
a
1
E si; » T?T«L
j| EFFLUENT •
1 I1' » . 1. H
«[' • ,. . . J-^J— ^
Jv
r
jJlvJiXjkiu
-UL
Figure 12.
Reconstructed total ion current of the volatile
organics in the
influent and effluent of the septic tank.
21
-------
1000
100
o
i 10
»~
X
0.1
0.01
O SanjR COMPOUNDS
A SENZENC COTOUNOS
O ALCOHOLS
10
20
Figure 13. Attenuation of volatile compounds during septic tank
treatment.
100
10
0.1
0.01
O HYDROCARBONS
10
Figure 14. Attenuation of volatile hydrocarbons during septic
tank treatment.
22
-------
APPENDIX A
DAILY ANALYSES (pg/L)
<
c
PURGIABUS
1. M«lh«ne, bronj-
2. Htthtne, IrtcMorofluoro-
(•wthrlenechlorldt)
4. tthenc,t.2-dlcMoro-
5. Cth«n«. l,l-dlchlort>-
6. Chloroform
7. Totutni
8. tthene, tftr«chloro-
9. Btnienc, chloro-
10. Benjtne, tthyl-
11. Methane, Irlbromo-
12. Clh«r>e. 1.1.1-
Trlchloro-
13. Ben^ne
14. Prop«ne.l .2-
01 hloro-
1S. tthc. c.trkMoro-
16. 1-Proprne.l .3-
dlchloroU)-
17. tlh«nf .1.1.2-
Irlchloro-
18. 1 .«-
fM ^
CV C
14.8
4 8
5.3
24.1
r* 3
cv c
V* 3
44.4
0.9
31.9
IN*
IN*
"I
1.0
0,7
0. C
4V V
V> 3
3 C
1 VZ
34 9
0.79/
0. C
22.2
zi
+* «J
0. C
V» 3
0.82
38.1
J.S7
c\ c
V tl
tn 3
32.9
O.IB
ex c
0. C
£5
i a
-/0.3
8.5/
SJj?
3.S/-
.n/
o c
1. C
fe. *-
0.1
47.8
J.9
** **
VI 3
iT«-
U. UJ
38.4
0. C
32.1
2.7
W» 3
0.4
48.9
79
CX C
1.9
25. J
4 ,
Su. Stot. 28
Effluent (UW
1.0
56.9
0.7
~
vt|
0.18
M.5
0.47
0.01
0.03
0.13
—
W» 3
0.37
44.9
0.17
0.03
~
S3
Ck C
VI 3
3 C
71,4
0.44
0.30
~
S3
ss
VI 3
•s
—
26.9
0.31
0.34
„
a c
*^C
3 *-
49.1
W
0.12
0.04
0.31
I—
• 4V
C4 «l
« _*
JX
0.01
(3.2
0.13
1.7
1.1
0.15
ro
CO
-------
APPENDIX A (continued)
DAILY ANALYSES (pg/L)
,
PVRCCABUS
1. Mtlhinf, bromo-
2. Mtthine, Irlchlororiuoro-
3. M{lb«nt, dlchloro
(««thrl«n«hlorld«)
4. lthcnc,t,2-4lcMoro-
S. (thine, 1,1-dlchloro-
6. Chloroform
7. Toluene
fl. tthene, ttlrichloro-
9. Bcniene, chloro-
10. Benjene, ethyl-
11. Helhjne, trlbromo-
12. tthjne. 1.1.1-
Trlchloro-
13. Beniene
14. Propane .1,2*
OlcMoro- '
IS. Uhfne.lrlchloro-
16'. 1 -Propf ne .1,3-
dlchloro(I)-
17. HMnf. 1,1,2-
tr Ichloco-
It. 1 ,<-dlchlorobtn-
o
r Ji^
u c
* *»
O 3
^"i
5?. 3
1.7
0.3S
3.0
19,1
1.2
O.S6
t-
r* ^*
15
U
« *
O o*
,•3
V> VI
lisa
3S(.3
u.a
f-*
O <
^«
r* c
i-
0 i.
V
• fc»
^3
O.d
O.JI
-
»—
•- O
* t,
c *
"!•!
»rt K-
0.7?
t-
^ O
• **
C C
^;
.c
J!i
0.7?
5,6
H-
— O
C C
i* V
*> ^
^'H
54.4
0.74
11.2
»-
r^ o
zZ
u c
2S
• s-
^i
4.1
o.eo
4.2
1.7
0.34
J.
fM O
US
25
• %.
^w
0.40
1.4
1.2
0.84
O..ZJ
0.28
: E
» s
fM*-»
e't
•?x
• i
^^
(9,9
^-
* 0
•M'*-
C C
4* «
O »
• <%.
5£
so.;
IO.S
19.7
0.011
M
as
• w
C C
•* t»
"> D
Ji'5
«.2
2.1
0.0'
~p
e t»
• 3
3 if
VI W
7997
1,9
16,5
^ h-
«*< *—
O
ft
• »
^^
134
231
?»,!
11,}
ISM
O
St.
^!
^'5
1S3
Q.H
,0)5
-------
APPENDIX A (continued)
DAILY ANALYSES (pg/L)
<
<
BASE-NEUTRAL EXIRACTA8LES
1. 1 ,4-Dichlorobenjene
2. Nitrobenzene
3. Acenaphthylene
ro 4. Di-N-Buthylphthalat*
3
• *-
^£
10.2
136
1.1
3.4
OD
CM
*-» *>
ex c
«V 4V
4/> D
»*»-
3 *-
vn uj
33.5
t?8
8.3
0.2.
14.4
09
CM
*>
a.
«» *•
»yi CT»
13
» 3
3 —
»X» »XI
16S
3004
18S9
297
6S23
. *«»
u c
4b 4V
a 3
j?!!
12.4
168
20.6
0.59
17
r^*
. **
0 C
«l «
O 3
3 «-
l/t t*J
141.7
r-
O 3
* **.
3 C
l/t —
123
21.55
14.6
. «j
c c
«J H
1 3
• Iw
3 *•-
4/t UJ
444
33.1
?4.6
C C
•« «l
•-> 3
• u.
3 »-
\n u«
32.0
74.2
1.9
21.8
30.9
6.6
^
CM
C
«
• 3
3 O
>n
607.4
52.8
37.2
1590.;
67.1
2057
107. 1
(7»
T3
• 3
3 •—
*n w^
9.6
50.6
18.2
3.6
12.9
26.6
*
rs« i.
•/
. *j
c «
» 31
O
3 V
»
7.9
11.0
0.6
1.2(
2.2
------- |