EPA-600/2-78-027
March 1978
Environmental Protection Technology Series
WASTEWATER TREATMENT FOR
REUSE AND ITS CONTRIBUTION TO
WATER SUPPLIES
Municipal Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
-------
EPA-600/2-78-027
March 1978
WASTEWATER TREATMENT FOR REUSE
AND ITS CONTRIBUTION TO WATER SUPPLIES
by
Howard P. Warner
John N. English
EPA-DC Pilot Plant
Washington, D.C. 20032
Contract No. 68-03-0344
Project Officer
Irwin J. Kugelman
Wastewater Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
-------
DISCLAIMER
This report has been reviewed by the Municipal Environmental Research
Laboratory, U. S. Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily reflect
the views and policies of the U. S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
11
-------
FOREWORD
The Environmental Protection Agency was created because of increasing
public and governmentconcern about the dangers of pollution to the health
and welfare of the American people. Noxious air, foul water, and spoiled
land are tragic testimony to the deterioration of our natural environment.
The complexity of that environment and the interplay between its components
require a concentrated and integrated attack on the problem.
Research and development is that necessary first step in problem
solution and it involves defining the problem, measuring its impact, and
searching for solutions. The Municipal Environmental Research Laboratory
develops new and improved technology and systems for the prevention, treat-
ment, and management of wastewater and solid and hazardous waste pollutant
discharges from municipal and community sources, for the preservation and
treatment of public drinking water supplies, and to minimize the adverse
economic, social, health, and aesthetic effects of pollution. This publi-
cation is one of the projects of that research; a most vital communications
link between the researcher and the user community.
The study summarized in this report evaluates a combined biological/
physical-chemical pilot treatment system designed to produce a high
quality reusable water. Process reliability is established and effluent
constituents are related to similar materials identified in finished
drinking waters.
Francis T. Mayo
Director
Municipal Environmental Research Laboratory
iii
-------
ABSTRACT
An 18 month study using cost effective municipal wastewater treatment
technology coupled with a computerized data handling system, was conducted
at the EPA/Washington, D.C. Blue Plains Pilot Plant to obtain data on the
safety of the effluent for discharge upstream of drinking water intakes, and
for potential domestic reuse purposes. Treatment reliability was demonstrated
and performance results showed the absence of virus in the effluent. Effluent
concentrations of radioactivity, trihalomethanes and other volatile organics,
heavy metals, pesticides, TOC, turbidity, general inorganic compounds, and
pathogenic indicator organisms were shown to be similar to those found in
finished drinking waters during the EPA National Organics Reconnaissance Survey
in 1975. The specific organic compounds identified in the effluent are also
present in finished drinking waters. Effluent organic concentrates did not
exhibit mutagenic properties, and results of an 80 element survey did not
detect the presence of significant quantities of any hazardous inorganic
material. Effluent endotoxin levels were comparable to levels in public
drinking water supplies.
This report was submitted in partial fulfillment of contract No. 68-03-0344
by the District of Columbia Pilot Plant under the sponsorship of the
U.S. Environmental Protection Agency. This report covers the period from
April 1975 to September 1976.
iv
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CONTENTS
Foreword iii
Abstract iv
Figures vi
Tables vii
Acknowledgements viii
1. Introduction 1
2. Conclusions 3
3. Description of Treatment System 4
4. Performance 8
Virus 8
Radioactivity 8
Volatile Organics 9
Toxicity Screening 9
Metals 9
Pesticides 21
General Organics 21
General Inorganics • 27
Nutrients 27
Suspended Matter 27
Microbiological and Disinfection Parameters 27
Esthetic Parameters 38
5. References 40
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FIGURES
Number Page
1 Schematic flow Diagram 5
2 Removal of Volatile Organics 13
3 Frequency Distribution of effluent mercury 20
4 Frequency distribution of effluent TOG 26
5 Removal of TOC 28
6 Frequency distribution of effluent COD 30
7 Frequency distribution of effluent turbidity 36
vi
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TABLES
Number
1 Design Data and Operating Conditions 5
2 Virus 9
3 Radioactivity 10
4 Volatile Organics 12
5 Volatile Organics in Process Effluents 14
6 Mutagenicity of Organic Concentrates 16
7 Results of Bacterial Endotoxin Testing 17
8 Heavy Metals 18
9 Heavy Metal Removal by Lime Clarification 22
10 Pesticides 23
11 General Organics 24
12 Variability of Effluent TOC 25
13 Variability of Effluent COD 29
14 General Inorganics 31
15 Results of 80 Element Survey 32
16 Nutrients 33
17 Suspended Matter 34
18 Variability of Effluent Turbidity 35
19 Microbiological and Disinfection Parameters 37
20 Esthetics 39
vii
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ACKNOWLEDGMENTS
A project of this magnitude, which covers 18 months of pilot plant
operations, could not have been accomplished without the assistance of the
entire EPA-DC Pilot Plant staff.
Mr. Paul Ragsdale supervised the mechanics and instrumentation personnel.
Mr. Calvin Taylor served as chief operator. Laboratory analyses were
performed under the direction of Mr. David Rubis. The efforts of all the
D.C. mechanics, technicians, crew chiefs, operators and laboratory personnel
are gratefully acknowledged.
Mr. Thomas A. Pressley and Ms. Stephanie G. Roan, On-site EPA staff,
performed the detailed organic identification work and virus analyses were
conducted by the Cincinnati EPA Virology Laboratory under the direction of
Mr. Daniel R. Dahling.
Special thanks are due Mr. Thomas P. O'Farrell, past Pilot Plant Chief,
for his efforts in the early stages of the project which enabled a timely
completion of fabrication of the treatment system.
viii
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SECTION 1
INTRODUCTION
We are living in a Nation where millions of people are presently reusing
wastewater indirectly for domestic purposes. Severe contamination of many
surface supplies has occurred, as evidenced by the identification of
carcinogenic organic materials in finished drinking waters, and increasing
instances of groundwater contamination are being found. There is a concern
on the part of health agencies in areas that use surface supplies for domestic
purposes as to the potential hazards of the present covert reuse of waste-
water discharged upstream of drinking water intakes. Since the typical
wastewater treatment plant does not remove all of the contaminants from the
wastewater there is a basis for this concern, and thus a need to know the
appropriate levels of municipal treatment to ensure the safety of water
supply intakes in the vicinity of the discharges.
The concerns of health agencies where covert reuse is prevalent are
also receiving attention by health agencies in the more arid areas of
the U.S. where water utilities are proposing the overt domestic reuse of
wastewater to supplement depleted groundwater supplies and unreliable surface
sources. Concerns about both covert and overt reuse are the same since the
problems and the research data required to solve the problems are the same.
The questions that need answers are:
0 • What are the health effects of the covert/overt reuse of
wastewater?
• What technology is needed to remove potential hazardous
materials?
The Environmental Protection Agency (EPA) through its Municipal
Environmental Research Laboratory (MERL) in Cincinnati, Ohio is addressing
the technology question by characterizing the ability of municipal waste-
water treatment systems to remove pollutants of health concern and providing
knowledge of treatment system performance variability and reliability.
A combined biological/physical-chemical treatment system designed to
produce a high quality reusable water has been in operation at MERL's
Washington, D.C. Pilot Plant for 18 months as*part of a project that had
the following objectives:
-------
Identification of specific pollutants in the final effluent
and evaluation of the performance of the individual pro-
cesses in removing these pollutants.
Provide data on process and system performance variability
and reliability with respect to pollutant removals.
-------
SECTION 2
CONCLUSIONS
Performance results showed the absence of virus in the effluent, and
concentrations of radioactivity, trihalomethanes and other violatile organics,
heavy metals, pesticides, TOC, turbidity, and microbiological parameters
similar to those found in finished drinking waters during the EPA National
Organics Reconnaissance Survey in 1975. The specific organic compounds
identified in the effluent are also present in finished drinking waters.
Effluent organic concentrates did not exhibit mutagenic properties and results
of an 80 element survey did not detect the presence of significant quantities
of any hazardous inorganic material. Effluent endotoxin levels were compara-
ble to levels in public drinking water supplies.
Treatment reliability was demonstrated as evidenced by the frequency
distribution of the day to day concentrations of chemical, physical, and
biological materials remaining in the effluent. In full scale facilities
employing similar treatment processes and located upstream of drinking water
intakes, or designed for domestic reuse purposes, reliability can be further
enhanced by in-plant storage facilities to provide flexibility, process
control instrumentation, and dedicated operating personnel. In planned
reuse situations where a monetary value is set on the water, or where enforced
legal restraints are placed on effluent quality reliability will become very
good.
-------
SECTION 3
DESCRIPTION OF TREATMENT SYSTEM
The treatment system was located on the grounds of the Washington, D.C.
Blue Plains wastewater treatment facility and was supervised by MERL staff
and operated in cooperation with the Washington, D.C. Department of Environ-
mental Services. The system treated degritted D.C. municipal wastewater using
a screening device to remove coarse materials, lime clarification, dispersed
growth nitrification, fixed film denitrification, carbon adsorption, dual
media filtration, and chlorination for disinfection. This sequence of
processes was chosen because of past experience with the performance of the
individual processes and compatibility of the unit processes when combined
into a treatment system that could produce a reusable high quality water from
municipal wastewater. Also, a similar treatment system was identified at a
workshop on "Research Needs for the Potable Reuse of Municipal Wastewater" ' '
as one of four treatment systems that had potential as a cost-effective
treatment for potable reuse.
A schematic flow diagram of the treatment system is presented in
Figure 1 and the design and operating conditions are summarized in Table 1.
The system operates continuously at 35 gpm (2.2 1/s). The backwash water
from the denitrification, carbon adsorption, and filtration processes are
returned to the influent of the lime clarification processes. A portion of the
sludges from the lime clarification and nitrification processes are wasted to
maintain process equilibrium.
The treatment system was operated on a continuous basis with operators
assigned to three, 8 hour shifts each day. Samples were taken manually by
the operators and composited in refrigerated containers as required.
Twenty-four hour composites were taken 5 days per week and no sampling was
done between Friday 8 a.m. and Sunday 8 a.m. Other types of sampling were
also done manually by the operators as required.
Establishing the reliability of any treatment system requires a long-
term program of routine monitoring of the system performance. A mass of
valuable data was obtained as a result of this program and an efficient
computerized data storage and retrieval system was developed to sort large
quantities of data per month from 37 performance or process monitoring
stations. The data storage and retrieval system was designed for use on the
EPA UNIVAC 1110 Computer located at EPA Research Triangle Park in North
Carolina. All the programs run in batch or demand mode. The system is
modular in design to allow the addition and modification of programs without
affecting the system integrity. Data is entered into and withdrawn from
the computer using a terminal hookup. Statistical reports, data listing,
as well as data plots can be obtained as required by project personnel to
aid in establishing the system performance credibility.
-------
HO
tt" BACKWASH TANK
S = LIME CLARIFICATION ST°RAGE
METHANOL —
18
19
f
H5
18
*—
i i
__! !H9
N
Y
DRAIN
AO NITRIFICATION
M
A2
A3
A4
1
A6
BACKWASH WATER FROM:
DENITRIFICATION COLUMNS,
CARBON COLUMNS,
AND FILTERS WASTE
f
WASTE
POLYMER KO
ii!. d
1
^
12
_i
-}|
13
f
17
j
J
1
J2
J3
DENITRIFICATION
CARBON ADSORPTION
}
4
1 7
_l
V
K1
I
K3
1
K
FILTRATION
HOLDING TANK
K7
CHLORINE
CONTACT
TANK
CHLORINATION
L7
FIGURE 1. SCHEMATIC FLOW DIAGRAM
FINAL EFFLUENT
-------
TABLE 1. DESIGN DATA AND OPERATING CONDITIONS
PARAMETER
VALUE
Raw Wastewater (Constant Flow)
Screening Device
Type
Size of Openings
Lime Clarification
Lime Dosage (pH 10.0)(as CaO)
FeCl_ Dosage (as Fe)
Hydraulic Loading Rate
Detention Time
Sludge Wasting Rate
Percent Solids in Waste Sludge
Nitrification (Suspended Growth)
Detention Time
MLSS
SRT
Air Requirement
Clarifier Overflow Rate and
Detention Time
Denitrification (Fixed Film)
Media Size
Specific Surface Area
Hydraulic Loading Rate
Methanol/N03-N Ratio
35 gpm (2.2 x 10"3m3/s)
Bauer Hydrasive Model 552
0.040 in. (1.02 mm)
200 mg/1
15 mg/1
1050 gpd/sq.ft. (42.8m3/m2d)
2.7 hr.
2% to 3%
1.5% to 2.0%
3.5 hr.
2000 mg/1
8 day
1450 cu.ft./lb BOD (90.6m3/k )
o
526 gpd/sq.ft. (21.4m3/m2d)
2-3.6 hr.
3 to 6 mm
245 sq.ft./cu.ft. (QOOm2^3^
5.9 gpm/sq.ft. (4.1 l/m2s)
2:1 to 4:1
-------
TABLE 1 (cont'd)
PARAMETER
VALUE
Bed Depth
Detention Time (Empty Bed)
Operation
Granular Carbon Adsorption
Detention Time (Empty Bed)
Hydraulic Loading Rate
Columns in Series
Carbon Size (Filtrasorb 300)
Operation
Filtration with Alum and Polymer
Hydraulic Loading Rate
Dual Media
Coal 1.2-1.4 mm
Sand 0.6-0.7 mm
Alum
Disinfection with Chlorine
Detention Time
Residual
15 ft. (4.6 m)
9.5 min.
Downflow Packed Bed
35 min.
7 gpm/sq.ft. (4.8 l/m2s)
4
8 x 30 Mesh
Downflow Packed Bed
3 gpm/sq.ft. (2.04 l/m2s)
2.0 ft. (0.61 m)
1.0 ft. (0.30 m)
5 mg/1
20 min.
1 mg/1 Free Available
-------
SECTION 4
PERFORMANCE
VIRUS
Virus in wastewater effluents are of concern to health agencies dealing
with the use of contaminated surface drinking water supplies and proposed
domestic reuse situations. For this reason it is important that virus analyses
be included in any reuse technology monitoring program. Virus and other patho-
gens were monitored at various points in the treatment system on three
occasions over a three month period using methods described by Rao, V.C.,
et al C2)and Wallace, C., et al<3>.
Samples of the raw sewage, finished effluent, and dual media filtration
effluent were taken during the first sampling period. As shown in Table 2
animal viruses in raw sewage samples ranged from about 7000 to more than
17,000 PFU/100 gal (1,850-4,500 PFU/100 1). No animal viruses were observed
in the dual media filtration effluent before chlorination, or the finished
effluent following concentration of 100-150 gal (379-568 1) of each effluent.
During the second and third months samples of the raw sewage, finished
effluent and effluent from the nitrifying activated sludge were taken. Animal
viruses in the raw sewage from 17,000 to 68,000 PFU/100 gal (4,500-18,000
PFU/100 1) and from 28,000 to 68,000 PFU/100 gal (7,400-18,000 PFU/100 1).
Animal viruses were not detected in the final effluent in either sampling
period. A total of 7 samples were concentrated during these periods ranging
in volume from 50 to 238 gal (190-900 1). During the last two sampling
periods, effluent from the nitrifying sludge system was tested on five
occasions following concentration of 40 to 160 gal (151-605 1) of each system.
In this phase of treatment, animal viruses still could not be detected.
Assays were carried out on solids remaining on prefilters used for clarifying
both the nitrification and final effluents. Viable animal viruses could
not be detected after processing these solids.
RADIOACTIVITY
Samples of effluent were periodically taken for gross beta and gross
alpha analyses and the results are summarized in Table 3. These levels are
well below the maximum contaminant level set forth in the EPA Interim Primary
Drinking Water Regulations ^' for radioactivity and they are comparable
to those reported in finished drinking water supplies
8
-------
TABLE 2. VIRUS
Sampling
Period
1
2
*t
o
Animal Virus pfu/100 liters
Influent
1,850 - 4,500
4,500 - 18,000
7,400 - 18,000
PROCESS
Nitrification
-
N.D.
N.D.
Filtration
N.D.
-
-
Chlorination
N.D.
N.D.
N.D.
Sample Volumes - 189 liters to 900 liters
N.D. - None Detected
-------
TABLE 3. RADIOACTIVITY
Sampling Period
1
2
3
4
Average in Drinking
Water*
Effluent Values pci/1
Gross Alpha
< 0.3
< 0.5
< 0.5
< 0.5
5.5
Gross
7.9 +
8.1 t
7.4 +
5.0 +
2.9
Beta
0.9
0.9
0.9
0.9
''Summary of Interstate Carrier Water Supply Radionuclide Data
"Preliminary Assessment of' Suspected Carcinogens in Drinking Water"
EPA, December 1975.
.10
-------
VOLATILE ORGANICS
Four trihalomethanes, carbon tetrachloride, and 1, 2 - dichloroethane
were determined in the influent and effluent from individual processes on a
twice per month basis to determine the effectiveness of the treatment system
in removing these materials. A summary of the influent and effluent concen-
trations of the compounds compared to the range of concentrations found in
finished drinking water supplies is included in Table 4. Figure 2 shows the
variation of the volatile organics through each process. Although the
concentrations are quite low there is definite indication that chlorination
increases the quantities of each of the six compounds.
Table 5 shows the results of analyses of other volatile organics in
the pilot plant influent and in the effluent from various unit processes.
The types of compounds and their corresponding concentrations are similar
to those present in finished drinking water supplies (•*' > Blanks in the
tables indicate the compounds were below the detection limit of the GC/MS
technique used (6)__
TOXICITY SCREENING
Organic materials were concentrated from 500 gal (1,900 1) samples of
effluent using a reverse osmosis technique that employed cellulose acetate
and nylon membranes in series (''. The concentrate from each type membrane
was extracted with pentane or methylene chloride at acidic (pH 2) and neutral
(pH 7) conditions. The separate extracts and a composite of the extracts
were tested for mutagenicity using the Ames procedure (Q) that utilizes iri
vitro microbiological assays with strains of Salmonella Typhimurium TA 98
and TA 100. No mutagenicity was detected as shown by the data in Table 6.
Table 7 shows the results of bacterial endotoxin tests on effluent
samples as compared to similar data from ten public drinking water systems.
These results were reported by Jorgensen, J.H., et al ^ from studies in
which they used a Limulus assay technique for the detection of bacterial
endotoxins. The concentration of endotoxins in the Blue Plains effluent
is comparable to the concentrations in public drinking waters.
METALS
Data on the metals present in the influent and effluent are presented
in Table 8 along with a list of the concentrations present in the Washington,
D.C. drinking water, and the levels allowed in finished drinking water
supplies as contained in the "EPA National Interim Primary Drinking Water
Regulations", December 1975 ^ . None of the effluent samples taken exceeded
metal concentrations cited in the EPA regulations. The reliability of the
treatment system to meet these regulations is further demonstrated by the
frequency distribution of effluent mercury for the second four month period of
operation as shown in Figure 3. All twenty two of the data values were less
than the 2 yg/1 standard. The median value was 0.70 yg/1.
11
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TABLE 4. VOLATILE ORGANICS
COMPOUNDS
(All Units
Vg/1)
Chloroform
Bromodi-
chloro-
methane
Dibromo-
chloro-
methane
Bromoform
Carbon Tet:
chloride
1,2-Dichlo
ethane
INFLUENT
NUMBER
OF
SAMPLES
14
14
14
14
ra- 13
ro-
14
ARITH.
MEAN
13
0.9
5.9
<0.1
5.6
9.7
RANGE
4.44
<0.1-4.5
<0.1-23
<0.1-0.2
<0.1-32
<0. 1-134
EFFLUENT
NUMBER
OF
SAMPLES
12
12
12
12
11
12
ARITH.
MEAN
8.0
5.4
5.2
2.6
1.0
0.5
RANGE
*FINISHED
DRINKING WATERS
RANGE OF
CONCENTRATIONS
<0.1-22
<0.1-2]
<0.1-28
<0.1-23
<0.1-S.
<0.!-2.
2
6
<0. 1-311
0.3-116
<0. 4-110
<0.8-92
<2-3
<0.2-6
DRINKING WATER
WASHINGTON, D.C.
(DELACARLIA
PLANT)
41
8
2
**N.D.
N.D.
<0.3
*Based on 80 samples from National Organics Reconnaissance Survey - "Preliminary Assessment of
Suspected Carcinogens in Drinking Water, Report to Congress", EPA, December 1975
**N.D. - None Detected
-------
0)
Q
Z
D
o
Q.
u
Z
<
o
CK
O
O
>
O CHLOROFORM
O BROMODICKLOROAAETHANE
X DIBROMOCHLOJIOMETHANE
A BROMOFORM
0 CARBON TETRACHLORIDE
1,2 DICHLOROETHANE
TREATMENT PROCESS
FIGURE 2. REMOVAL OF VOLATILE ORGANICS
13
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TABLE 5. VOLATILE ORGANICS IN PROCESS EFFLUENTS
Compound
(Unit yg/l)
Acetaldehyde
Methanol
Acetone
Dichloro-
methane
Acrolein
Carbon
Disulfide
Chloroform
Bromodichloro-
methane
1,1,1-Tri-
chloroethane
Chlorodir
bromoethane
Benzene
Influent
TR.*
TR.
TR.
4
TR.
TR.
10
1
TR.
4
2
Nitri-
fication
TR.
3
TR.
TR.
1
Denitri-
fication
TR.
TR.
TR.
TR.
2
1
Carbon
TR.
TR.
1
TR.
5
TR.
1
Chlorin-
ation
TR.
TR.
TR.
TR.
7
4
2
2
Drinking
Water**
„,
j
j
J
/
j
/
/
/
j
-------
TABLE 5 (cont'd)
Compound
(Unit yg/1)
Dimethyl
disulfide
Toluene
N-Hexanol
Tetrachloro-
ethylene
Xylene
Alkyl benzene
Benzaldehyde
Carbon
tetrachloride
Influent
3
2
3
TR.
TR.
2
Nitri-
fication
TR.
TR.
TR.
Denitri-
fi cat ion
TR.
TR.
TR.
TR.
Carbon
TR.
TR.
TR.
TR.
Chlorin-
ation
TR.
TR.
2
TR.
Drinking
Water**
'
'
/
'
'
/
Ul
* TR. - Trace (<1 yg/1)
** "Preliminary Assessment of Suspected Carcinogens in Drinking Water," Report to Congress,
EPA, Dec. 1975.
-------
TABLE 6. MUTAGENICITY OF ORGANIC CONCENTRATES
R.O. Membrane
and
Solvent Fraction *Mutagenic Potential
Cellulose Acetate
• Pentane **N.D.
• Methylene Chloride Neutral N.D.
• Methylene Chloride Acidic N.D.
Nylon
• Pentane N.D.
• Methylene Chloride Neutral N.D.
• Methylene Chloride Acidic N.D.
Composite N.D.
.. .._ .. _^ ...._.._ .. _.,...._ ^. _.. . ...---..-..... ....,_._—...._.- , ., . _»,— . _.—.^ -„-•,-„_
* — VJ-tro with strains of salmonella typhimurium TA98 and TA100
** N.D. - None Detected
16
-------
TABLE 7. RESULTS OF BACTERIAL ENDOTOXIN TESTING*
SOURCE
Blue Plains Reuse System
Public Drinking Water Systems
1
2
3
4
5
6
s
7
8
9
10
ENDOTOXIN EQUIVALENTS
ng/ml
2.5 - 12.5
1.25
12.5
2.5
12.5
0.625
500.0
125.0
10.0
2.5
2.5
*Limulus Assay Procedure - Jorgensen et al., Applied and Environmental
Microbiology, September 1976.
17
-------
TABLE 8. HEAVY METALS
Metal
(Unit-yg/1)
Mercury
Cadmium
Selenium
Chromium
Lead
Manganese
Arsenic
Iron (mg/1)
Barium
Copper
Zinc
Boron (mg/1)
Final Effluent
n
47
44
38
57
53
60
56
227
49
56
57
8
Arit. Mean
0.666
0.143
4.76
2.24
0.308
7.96
2.25
0.0599
82.3
4.86
10.6
0.313
Range
0.100-1.25
0.020-0.530
2.00-5.00
0.600-4.30
0.030-1.07
1.40-20.0
0.300-6.00
N.D. -0.810
3.10-200
1.40-21.0
5.10-19.1
0.300-0.400
Washington, DC
Drinking
Water*
<0.5
<2
<5
<5
<5
<5
<50
EPA
Regulations**
2
10
10
50
50
50
1000
-------
TABLE 8. (cont'd)
Metal
(Unit-yg/1)
Flour ide (mg/1)
Silver
Cyanide
Aluminum (mg/1)
Final Effluent
n
62
49
32
210
Arit. Mean
0.722
0.134
4.23
0.251
Range
0.380-1.10
0.009-0.400
1.00-9.80
N.D. -0.900
Washington, DC
Drinking
Water*
1.0
<10
<20
EPA
Regulations**
1.8 @ 65°F
50
*"Preliminary Assessment of Suspected Carcinogens in Drinking Water"
Report to Congress, EPA, December 1975.
**National Interim Primary Drinking Water Regulations, EPA, Federal Register,
Vol. 40, No. 248, December 1975.
-------
PERIOD 2
N=22
ARITHMETIC MEAN - 0.720
GEOMETRIC MEAN - O.685
MEDIAN - 0.695
STANDARD DEVIATION - 0.245
I I ' i t t i i i I i i i
0.0001
0.0020
0.0500 0.3000 0.70OO 0.9500 O.9950
FRACTION EQUAL TO OR LESS THAN GIVEN CONCENTRATION
0.9999
FIGURE 3. FREQUENCY DISTRIBUTION OF EFFLUENT MERCURY
-------
In addition to determining metals in samples of the AWT system influent
and effluent, the effluent from the lime clarification process was monitored
for a four month period since previous data has shown that heavy metals can
be removed by this process. Table 9 shows that concentration of metals in
the influent, after the lime process, and in the final effluent. It is
evident that the lime process is primarily responsible for the reduction in
the metal concentrations.
PESTICIDES
Pesticide analyses were made on a less frequent basis than were analyses
for metals. The data presented in Table 10 are based on samples taken twice
per month. The levels in the effluent are significantly less than the EPA
standards for drinking water that are listed in the table.
GENERAL ORGANICS
A summary of various gross measurements or organics in the influent and
effluent is presented in Table 11 and includes the average of the parameters
for a 14 month operation period. The treatment system is capable of reliably
producing a high quality effluent on a continuous basis as evidenced by the
TOG data presented in Table 12 and Figure 4. The 311 pieces of TOG data were
grouped into 5 periods covering 18 months of operation and the arithmetic
averages and standard deviations were determined. The average TOG in the
finished drinking waters from 80 U.S. cities '*' is included in Table 12 for
comparison purposes.
Figure 4 is a frequency distribution of 77 pieces of TOG data taken
during the fifth and last period of operation. Included in the figure for
comparison purposes is a frequency distribution of the TOG data from 80
drinking waters taken during the National Organics Reconnaissance Survey
in 1975 (5^. The median TOG concentrations were 1.5 mg/1 for the drinking
waters and 2.5 mg/1 for the wastewater effluent. The lower levels of TOG in
the drinking water data may be attributed to the cities in the survey using
groundwater supplies.
In an attempt to determine if additional TOG reduction was possible grab
samples of effluent were ozonated on three separate occasions. An ozone
dosage of 60 mg/1 in the gas stream was introduced.into a 1 liter sample
using the reactor system described by Roan, S. * . The sample was reacted
with the ozone stream for 60 minutes. The initial average TOG concentration
was 1.21 mg/1 and the final TOG was 0.84 mg/1 which is a reduction of 30
percent. In addition, a short term side stream study was conducted using a
strong acid cation resin in series with an intermediate base anion resin to
determine the removal of the remaining TOG by ion exchange. These resins
reduced the effluent TOG about 40 percent.
21
-------
TABLE 9. HEAVY METAL REMOVAL BY LIME CLARIFICATION
Metal
(Unit-yg/1)
Mercury
Cadmium
Selenium
Chromium
Lead
Manganese
Arsenic
Iron (mg/1)
Barium
Copper
Zinc
Boron (mg/1)
Fluoride (mg/1)
Silver
Cyanide
Aluminum (mg/1)
Influent
0.813
1.92
4.76
16.9
23.4
149
1.49
1.30
54.3
48.9
110
0.250
0.701
3.98
5.80
-
Lime
Clarification
0.931
-
-
5-59
0.682
19.5
1.05
-
34.3
7.72
10.7
-
0.679
0.333
-
-
Final
Effluent
0.802
0.143
4.76
3.18
0.399
5.04
0.967
0.0467
27.2
5.66
12.6
0.313
0.724
0.0987
4.23
0.251
22
-------
TABLE 10. PESTICIDES
Pesticide
Unit - ng/1 (ppt)
Effluent**
*EPA
Regulations
Aldrin
DDT
Dieldrin
Endrin
Heptaclor
Heptaclor Epoxide
Lindane
Methoxychlor
Diazin
Guthion
Malathian
Parathian
4
10
1
5
0.7
1
2
40
5
200
10
10
200
4000
105
*EPA National Interim Primary Drinking Water Regulations, Federal
Register, Vol. 40, No. 248, December 24, 1975
**Average of 4 data values for each pesticide
23
-------
Table 11. GENERAL ORGANICS
PARAMETER
(units - mg/1)
TOC
COD
BOD
MBAS
CCE
CAE
Phenol
(yg/i)
UV @ 290
mu (%T)
INFLUENT
N*
231
229
245
13
-
-
9
-
Arithmetic
Mean
74.1
240
106
8.92
-
-
12.9
i. - - -
Standard
Deviation
11.0
30.5
15.7
1.71
-
-
4.02
-
EFFLUENT
N
234
226
221
35
2
2
54
19
Arithmetic
Mean
2.79
6.53
3.12
0.14
0.75
2.25
3.66
96.9
Standard
Deviation
1.35
3.12
2.15
0.08
0.64
0.64
1.52 i
0.87
NJ
*N-number of samples
-------
TABLE 12. VARIABILITY OF EFFLUENT TOG
4 Month
Periods
1
2
3
4
5
Total
*Finished
Drinking
Water
Number of
Samples
58
64
69
43
77
311
80
Arithmetic
Mean (mg/ 1 )
2.26
2.35
3.72
2.67
2.68
2.76
2.21
Standard
Deviation
1.31
1.00
1.59
1.50
1.02
-
Range
0.05-12.2
'Preliminary Assessment of Suspected Carcinogens in Drinking Water,"
Report to Congress, EPA, December 1975.
25
-------
u
O
ARITHMETIC MEAN - 2.68
GEOMETRIC MEAN - 2.50
MEDIAN - 2.50
STANDARD DEVIATION - 1.02
PRELIMINARY ASSESSMENT OF CARCINOGENS
IN DRINKING WATER*, EPA, DEC. 1975
FINISHED DRINKING WATER-80 CITIES .
I I I I I I I
0.0001
0.0020 0.0500 0.3000 0.7000 0.9500
FRACTION EQUAL TO OR LESS THAN GIVEN CONCENTRATION
FIGURE 4. FREQUENCY DISTRIBUTION OF EFFLUENT TOC
0.9950
0.9999
-------
Figure 5 shows a graph of the removal of TOC by each of the processes
in the treatment system. Ninety-two percent of the TOC is removed in the
lime clarification and nitrification processes. The increase in TOC in the
denitrification process effluent is due to some leakage of methanol.
Table 13 shows the variability of the effluent COD for each of the five
operating periods and Figure 6 shows a frequency distribution of 74 pieces
COD data taken during the fifth operating period. The median COD value
is 5.61.
GENERAL INORGANICS
A summary of the inorganic constituents in the influent and effluent is
presented in Table 14. The arithmetic means and standard deviations of each
constituent are shown. Samples of the effluent were checked for 80 elements
by the Proton Induced X-ray Emission Procedure ^ ' to determine the presence
of any unusual inorganic component. The results are shown in Table 15. No
significant concentrations of hazardous inorganics were observed.
NUTRIENTS
The concentration of the phosphorus and nitrogen compounds are shown
in Table 16. Over 200 pieces of data were used for each parameter in determining
the means and standard deviations. No attempt was made to completely
denitrify the effluent. The amount of methanol added to the denitrification
process was based on allowing 2 to 4 mg/1 of N03~N in the effluent.
SUSPENDED MATTER
Turbidity, and suspended and total solids data for the treatment system
influent and effluent are shown in Table 17. The effluent turbidity level is
within the requirements of the EPA National Interim Primary Drinking Water
Regulations (4) which establishes the standard at 1 turbidity unit on a
monthly average basis. The variability of the effluent turbidity is shown
in Table 18. At the beginning of the last four months of operation (period 5)
it was noted that the turbidimeter had not been properly standardized when
making readings. Implementation of the correct standardization procedure
accounts for the lower turbidity values during the fifth period. Figure 7
is a frequency distribution of the 332 turbidity values for samples taken in
period five. Between 98 and 99 percent of the values were less than the
standard of one. The median turbidity was 0.39 FTU.
MICROBIOLOGICAL AND DISINFECTION PARAMETERS
Data on the chlorine dosage, demand, and free residual in the effluent
are included in Table 19 along with data on the concentration of various
pathogenic indicator organisms. The free residual chlorine concentration
of 2.23 mg/1 and low turbidity of 1 FTU have combined to produce an effluent
that consistently meets the EPA Drinking Water Regulations.
27
-------
60
O)
E
20
10
* & <
4? J$
TREATMENT PROCESS
FIGURE 5. REMOVAL OF TOC
28
-------
TABLE 13. VARIABILITY OF EFFLUENT COD
4 Month
Periods
1
2
3
4
5
Total
Number of
Samples
58
64
67
37
74
300
Arithmetic
Mean (mg/1)
5.28
5.96
7.64
7.45
6.25
6.45
Standard
Deviation
2.55
3.09
2.54
3.29
2.20
-
29
-------
Ul
o
PERIOD 5
N=74
ARITHMETIC MEAN - 6.25
GEOMETRIC MEAN - 5.92
MEDIAN - 5.61
STANDARD DEVIATION - 2.20
1 1 1 I I I I I I I I I I I I I
O.OO01 0.0020 0.0500 0.3000 0.7000 0.9500 0.9950
FRACTION EQUAL TO OR LESS THAN GIVEN CONCENTRATION
FIGURE 6. FREQUENCY DISTRIBUTION OF EFFLUENT COD
0.9999
-------
TABLE 14. GENERAL INORGANICS
PARAMETER
(unit - mg/1)
PH
Total
Alkalinity
Conductivity
(umhos/cm)
TDS
Hardness
CaCo3
Stability
Chloride
Sulphate
Calcium
Magnesium
Sodium
Potassium
INFLUENT
N*
2274
2435
-
137
35
-
-
-
176
178
-
-
Arithmetic
Mean
7.20
125
-
283
115
-
-
-
31.2
6.47
-
-
Standard
Deviation
0.118
15.1
_
28.6
7.65
_
-
-
2.73
0.579
-
-
EFFLUENT
N
1081
980
830
210
40
40
158
122
218
224
228
21
Arithmetic
Mean
7.34
102
514
357
162
0.198
68.6
50.1
56.6
5.49
34.1
8.23
Standard
Deviation
0.146
12.1
36.0
31.6
7.18
0.394
4.56
3.83
4.40
0.481
2.94
0.318
* N-number of samples
U»
-------
TABLE 15. RESULTS OF 80 ELEMENT SURVEY*
Elements Detected in Effluent
Cng/1)
Na - 37.8 Zn - 0.017 Ba - 0.034
K - 7.08 Cd - 0.002 As - 0.006
Ca - 54.0 I - 0.013 NI - 0.004
V - 0.003 Pb - 0.003 Cu - 0.013
Cr - 0.001 Ga - 0.001 Sr - 0.151
Fe - 0.031 Br - 0.100 Sn - 0.002
Co - TR. Rb - 0.007 S - 2.85
Elements Not Detected
Ong/1)
Mn, Mo, Ag, Sc, Ti, Ge, Y, Pd, In, Sb, Te, Cs, La, W,
Pt, Tl, Bi, Si, P, Ar, Se, Kr, Zr, Nb, Ru, Rh, Xe, Ce, Pr,
Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, Re,
Os, Ir, Au, Hg, Po, At, Rn, Fr, Ra, Ac, Th, Pa, U, Np, Pu
*Proton - Induced X-Ray Emission Procedure
32
-------
TABU- 16. NUTRIENTS
PARAMETER
(unit - mg/1)
TP04
TKN
NH3-N
N03+N02-N
N*
244
128
24.3
232
INFLUENT
Arithmetic
Mean
15.1
19.0
17.5
0.095
Standard
Deviation
2.19
2.50
2.32
0.08
N
232
98
223
229
EFFLUENT
Arithmetic
Mean
0.153
0.222
0.069
3.84
Standard
)eviation
0.09
0.17
0.15
1.84
* N-number of samples
33
-------
TABLE 17. SUSPENDED MATTER
PARAMETER
(unit - mg/1)
Turbidity
(FTUD
Suspended
Solids
Volatile
Suspended
Solids
Total
Solids
INFLUENT
N*
_
241
294
-
Arithmetic
Mean
_
109
84.0
-
Standard
Deviation
-
21.3
16.0
-
N
1395
225
.
209
EFFLUENT
Arithmetic
Mean
0.884
1.02
mm
362
Standard
Deviation
0.448
0.954
.
30.4
* N-number of samples
34
-------
TABLE 18. VARIABILITY OF EFFLUENT TURBIDITY
4 Month
Periods
1
2
3
4
5
Total
Number of
Samples
161
262
313
327
332
1395
Arithmetic
Mean (FTU)
0.730
0.885
1.06
1.26
0.418
0.884
Standard
Deviation
0.256
0.800
0.464
0.520
0.182
-
35
-------
o
o
u>
o
GO
o
o
PERIOD 5
N= 332
ARITHMETIC MEAN - 0.420
GEOMETRIC MEAN - 0.386
MEDIAN - 0.385
STANDARD DEVIATION - 0.182
CO
oe.
I I I I I I I
I
I I I I I I I I I I I I 1 I I I I
I
II I I i I
es
0.0001
0.0020
0.0500 0.3000 0.7000 0.9500 0.9950
FRACTION EQUAL TO OR LESS THAN GIVEN CONCENTRATION
0.9999
FIGURE 7. FREQUENCY DISTRIBUTION OF EFFLUENT TURBIDITY
-------
TABLE 19. MICROBIOLOGICAL AND DISINFECTION PARAMETERS
PARAMETER
Chlorine Dosage mg/1
Chlorine Demand mg/1
Chlorine Residual
(free) mg/1
Total Coliforms
cells/100 ml
Fecal Coliforms
cells/100 ml
Pseudomonas
Aeruginosa
cells/100 ml
Salmonella
cells/100 ml
Total Count
cells/100 ml
EFFLUENT
N*
2030
43
57
114
119
36
40
44
Arithmetic
Mean
4.35
1.83
2.23
0.11
0.17
0.81
0
66.8
Standard
Deviation
-
1.62
1.45
0.39
O.SO
1.53
0
42.3
*N-Number of samples
37
-------
ESTHETIC PARAMETERS
The effluent had no odor when compared to samples of odor free water
prepared for the threshold odor test, and exhibited a level of color equal
to 3.5 color units based on the platinum - cobalt standard. This data along
with the average influent and effluent temperature are shown in Table 20.
38
-------
TABLE 2Q. ESTHETICS
PARAMETER
Temperature
(°C)
Odor (TON)
Color
(P-C units)
N*
382
-
-
INFLUENT
Arithmetic
Mean
20.9
-
-
Standard
Deviation
2.50
-
-
N*
320
35
84
EFFLUENT
Arithmetic
Mean
22.0
**N.D.
3.52
Standard
Deviation
2.32
N.D.
0.37
*N-number of samples
**N.D. - none detected
39
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SECTION 5
REFERENCES
1. "Research Needs for the Potable Reuse of Municipal Wastewater",
EPA-600/9-75-007, Dec. 1975.
2. Roa, V. C., et al., "A Simple Method for Concentrating and Detecting
Viruses in Wastewater". Water Research 6_: 1565-1576, 1972.
3. Wallace, C., et al., "A Portable Virus Concentrator for Testing Water
in the Field". Water Research 6_: 1249-1256, 1972.
4. "National Interim Primary Drinking Water Regulations", EPA, Federal
Register, Vol. 40, No. 248, Dec, 1975.
5. "Preliminary Assessment of Suspected Carcinogens in Drinking Water",
Report to Congress, EPA, Dec. 1975.
6. Bellar, T. A., S Lichtenberg, J. J., "The Determination of Volatile
Organic Compounds at the yg/l Level in Water by Gas Chromatography",
EPA-670/4-75-009, Nov. 1974.
7. Smith, J. K., et al., "Characterization of Reusable Municipal Wastewater
Effluents and Concentration of Organic Constituents", EPA Contract
Project No. 68-03-2090 (Final Report in review stage).
8. Ames, B. N., et al., Proceedings of the National Academy of Sciences,
Vol. 70, p. 2281, 1973.
9. Jorgensen, J. H., et al., "Rapid Detection of Bacterial Endotoxins in
Drinking Water and Renovated Wastewater", Applied and Environ. Microb.,
Vol. 32, No. 3, p. 347, Sept. 1976.
10. Roan, S. G., et al., "Laboratory Ozonation of Municipal Wastewaters",
EPA-670/2-73-075, Sept. 1973.
11. Sims, P., "Proton Induced X-ray Emission Procedure", Dept. of Physics,
Purdue University.
40
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
i REPORT NO.
EPA-600/2-78-027
2.
4. TITLE AND SUBTITLE
WASTEWATER TREATMENT FOR REUSE AND ITS CONTRIBUTION
TO WATER SUPPLIES
6. PERFORMING ORGANIZATION CODE
3. RECIPIENT'S ACCESSION-NO.
5. REPORT DATE
March 1978 (Issuing Date)
7. AUTHOR(S)
Howard P. Warner
John N. English
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Government of the District of Columbia
Department of Environmental Services
EPA-DC Pilot Plant, 5000 Overlook Ave., S.W.
Washington, D.C. 20032
10. PROGRAM ELEMENT NO.
11. CONTR~A"CT7Cnilli|IIT MO.
68-03-0344
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory—Cin.,OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
FINAL. 4/75 to 9/76
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Project Officer: Irwin J. Kugelman 513/684-7633
16. ABSTRACT
An 18 month study using cost effective municipal wastewater treatment
technology coupled with a computerized data handling system, was conducted
at the EPA/Washington, D.C. Blue Plains Pilot Plant to obtain data on the
safety of the effluent for discharge upstream of drinking water intakes, and
for potential domestic reuse purposes. Treatment reliability was demonstrated
and performance results showed the absence of virus in the effluent. Effluent
concentrations of radioactivity, trihalomethanes and other volatile organics,
heavy metals, pesticides, TOC, turbidity, general inorganic compounds, and
pathogenic indicator organisms were shown to be similar to those found in
finished drinking waters during the EPA National Organics Reconnaissance
Survey in 1975. The specific organic compounds identified in the effluent
are also present in finished drinking waters. Effluent organic concentrates
did not exhibit mutagenic properties, and results of an 80 element survey did
not detect the presence of significant quantities of any hazardous inorganic
material. Effluent endotoxin levels were comparable to levels in public
drinking water supplies.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Waste Treatment
*Water Reclamation
Nutrients
Viruses
Organic Compounds
Potable Water
Microorgani sms
b.lDENTIFIERS/OPEN ENDED TERMS
Reuse
Heavy Metals
Advanced Wastewater
Treatment
COSATI Field/Group
13B
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
49
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
41
«U.S. GOVERNMENT PRINTING OFFICE: 1978 260-880/16 1-}
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