United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-84-031 Feb. 1984
SERA Project Summary
Advanced Treatment for
Wastewater Reclamation at
Water Factory 21
Perry L. McCarty, Martin Reinhard, Naomi L Goodman, James W. Graydon,
Gary D. Hopkins, Kristien E. Mortelmans, and David G. Argo
The performance and reliability of
Water Factory 21 (WF21) in Orange
County, California, for removing a range
of organic, inorganic, and biological
contaminants from activated-sludge-
treated municipal wastewater were
evaluated. This 0.66 mVs (15 mgd)
facility includes chemical treatment, air
stripping, activated carbon adsorption,
reverse osmosis (RO) treatment, and
disinfection. The effluent is used to
furnish water for a hydraulic barrier that
prevents sea-water intrusion into the
local fresh water aquifer. This report is
the final one of three describing the
operation of WF21 over a 5-year period
and covers the last 3-year period when
analyses were most intensive.
Analyses were conducted for viruses,
coliforms, general inorganics, heavy
metals, radioactivity, several collective
parameters such as total dissolved
solids (TDS), chemical oxygen demand
(COD), total organic carbon (TOC), total
organic halogen (TOX), ultraviolet ab-
sorption, and total trihalomethane form-
ing potential (TTHMFP). In addition,
mutagenic analyses were conducted,
and a broad spectrum of individual
organic contaminants were measured,
including most of those on the EPA list
of priority pollutants.
Some objectives of this study were:
1. Determine the availability of the
treatment plant for producing
reclaimed water.
2. Determine the plant's reliability in
meeting local and state water
quality requirements and EPA
primary and secondary drinking
water standards. However, this
report recognizes that existing
drinking water standards are in-
adequate to define the potability
of renovated wastewater and that
a series of chemical, toxicological
and microbiological investigations
will yet be required before compre-
hensive standards and criteria to
define potable water regardless of
source can be developed.
3. Compare the quality of the re-
claimed water with EPA priority
pollutant health criteria.
4. Determine the cost of wastewater
reclamation with and without RO
treatment.
This information should prove useful to
others who are contemplating advanced
treatment for reclamation of waste-
waters for beneficial uses.
This Project Summary was developed
by EPA's Municipal Environmental
Research Laboratory. Cincinnati, OH,
to announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
Water Factory 21 (WF21)isa0.66m3/s
(15 mgd) adva need wastewater treatment
plant operated by the Orange County
Water District in Ca.lifornia. The reclaimed
water that is produced supplies injection
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water for a hydraulic barrier to prevent
sea-water intrusion into the local ground-
water supply. The processes used to
reclaim activated-sludge-treated munici-
pal wastewater are lime treatment, air
stripping, recarbonation, filtration, granu-
lar activated carbon adsorption (GAC),
RO, and chlorination. The water produced
by this series of processes is of high
quality, and there is interest in its poten-
tial for augmenting a drinking water
supply. The results of a broad investiga-
tion evaluate the quality of the reclaimed
water and the reliability of WF21 so that
judgments might be made of its potential
for such a purpose. This report is the third
in a series describing the overall per-
formance of WF21 from the time opera-
tion began m October 1976 through
March 1981.
Approach
Primary emphasis in the study was on
the performance of the advanced waste-
water treatment plant (AWT) defined here
as all processes except RO, and the overall
plant including RO treatment (AWT+RO).
The efficiency of the plant was evaluated
by comparing influent and chlorinated
effluent samples for AWT and influent
and RO effluent samples for AWT+RO.
Samples were collected every 6 days
from the AWT and AWT+RO influent and
effluent and every 12 days from inter-
mediate points to evaluate the perform-
ance of individual processes.
The flow rate to the various processes
varied throughout the study period. The
0.22 mVs (5 mgd) RO facility was oper-
ated at near full capacity essentially for
the entire period reported, but the AWT
chlorinated effluent flow varied consider-
ably (0.05 to 0.37 mVs) because of
changing needs for reclaimed water and
changing operating philosophies. Also,
the fans associated with the stripping
towers were not operated for essentially
the entire period because ammonia re-
moval requirements were modified.
In general, lognormal distribution was
used to analyze data to determine geo-
metric mean concentrations, 95% confi-
dence intervals for means, and spread
factors. Percentage removals for consti-
tuents by individual processes or the
overall plant and 95% confidence inter-
vals were also determined.
Sampling and Analytical
Procedures
Grab and composite samples were
collected and stored under refrigeration
before organic and inorganic analyses.
Composite samples were prepared by
mixing equal volumes of 8 grab samples
taken manually at 3-hour intervals over a
24-hour period. Analyses for COD, TOC,
inorganic constituents, and heavy metals
were conducted on daily composite sam-
ples using standard procedures by the
WF21 analytical laboratory. Viral analyses
were conducted by James Montgomery
Engineers, Pasadena, CA. Specific organ-
ic constituents were analyzed by the
Stanford Water Quality Control Research
Laboratory on samples shipped by air in
insulated containers that arrived on the
same day. Mutagenic analyses were
conducted on selected samples using the
Ames assay for point mutation in Sal-
monella typhimurium by SRI Interna-
tional, Menlo Park, CA.
Among the organic analyses conducted
were a group of collective parameters
including ultraviolet absorbance (UVA),
TOX, and TTHMFP, as well as COD and
TOC. Individual organic constituents were
determined by five different gas chromato-
graphic (GC) procedures with emphasis
on compounds contained in the EPA list
of priority pollutants, although many
other compounds found present were
also measured. Volatile organic analysis
(VOA) measured one- and two-carbon
halogenated compounds by pentane ex-
traction and electron capture (EC) detec-
tion. A range of volatile aromatic and
aliphatic compounds was determined by
closed loop stripping analysis (CLSA)
using GC equipped for hydrogen-flame
detection. Chlorinated hydrocarbon pesti-
cides, PCB's, and similar compounds
were determined on hexane extracts and
capillary-column GC with EC detection.
Other basic and neutral compounds were
determined through continuous liquid-
liquid extraction (CLLE) with methylene
chloride and analysis with a Finnigan
GC/MS system model 4000*, controlled
by an INCOS data system. Acids and
phenols (A/P) were determined in a
similar way, but on acidified and methyl-
ated samples. The analytical procedures
used analyzed quantitatively 100 of the
114 organic priority pollutants. Most of
the compounds for which the techniques
were suitable could be analyzed with
detection limits generally of 0.01 to 0.05
Findings
• Reclaimed water with and without RO
treatment met EPA interim primary
•Mention of trade names or commercial products
does not constitute endorsement or recommenda-
tion for use.
drinking water regulations more than |
95% of the time (except for coliforms in "
the unchlorinated RO effluent). Since
no comprehensive standards and cri-
teria currently exist to define potable
water regardless of source, none of
the above should be construed to mean
that the described product water was
potable.
• Reclaimed water with RO treatment
met all EPA secondary drinking water
criteria, and without RO treatment, the
water met most of the standards except
for pH and general mineral parameters
such as TDS, chlorides, and sulfates.
These conclusions apply to all second-
ary standards except odor and corro-
sivity, which were not measured.
• Effluent mean concentrations (even
without RO treatment) met the health
criteria at the 10~6 life-time risk level
for most of those priority pollutants not
currently covered by EPA primary or
secondary regulations and for which
the limits are above the analytical
detection limit. No judgments can be
made for compounds below the analyt-
ical detection limit (10 to 100ng/L)or
priority pollutants not quantified by the
procedures used. Also, the list of prior-
ity pollutants does not include all m
potentially toxic chemicals.
• Mutagenic activity by the Ames test
was detected frequently in influent
samples and after points of chlorina-
tion, but was reduced by activated
carbon treatment. However, mutagen-
ic activity was recreated on terminal
chlorination following carbon treat-
ment.
• Brominated alkylphenol polyethoxy
carboxylates were tentatively identi-
fied in reclaimed wastewater during
chlorination and among the major
compounds present in the mutagenic
organic fractions following chlorina-
tion of effluent.
• Mutagenic compounds appeared to be
associated with hydrophobic organic
acids, and activity was reduced when
metabolic activators were included in
the test.
• Although enteric viruses generally
were present in the influent, they were
detected in the effluent in only one
case during this phase of the study.
No evidence was found indicating that
this reclaimed municipal wastewater
would pose a significant health risk
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when used as a source of municipal
water supply, but generally detailed
toxicological testing is needed to draw
valid conclusions.
• Ultraviolet absorption was not a satis-
factory surrogateTbTrnomtor ing organ-
ic material during treatment, partly
because of a significant positive chlor-
ine interference and partly because of
a lack of good statistical correlation
with TOC or any other organic chemi-
cals measured.
• TOC and COD are good surrogates at
WF21 for monitoring the performance
of GAC columns in removing the trace
organic compounds.
• Barium and manganese are promising
indicator chemicals for monitoring the
range of trace heavy metal removal by
lime treatment.
• Promising indicator chemicalsfor mon-
itoring the range of removals by air
stripping are 1,1,1-trichloroethane,
tetrachloroethylene, and 1,2- and 1,4-
dichlorobenzenes.
• During the 3-year study, the treatment
plant through final chlorination was
operated 74% of the time. Of the 26%
shutdown time, 7.4% was for chlorine
basin repair, 7.8% for conducting a
hydrogeological study of the ground-
water basin, 5.1 % for planned general
maintenance, 1.6% for external causes,
and 5.5% for other equipment failures,
repairs, or modifications.
• The treatment plant through RO treat-
ment (not affected by final chlorination
basin repairs or the hydrogeological
study) was operated 89% of the time.
About one-half of the 11% downtime
was for planned treatment plant main-
tenance and the other one-half for
external causes and equipment fail-
ures, repairs, or modifications.
• Producing blended water for ground-
water injection during the 1980-81
year cost $0.43/m3; 64% was for
operation and maintenance and the
remainder for capital depreciation.
Costs are increased because the plant
was not,operated at design flows
during this period.
• Projected costs/m3 of treated water,
assuming operation at design flow
with 90% plant availability factor, are
$0.20for advanced treatment without
RO, $0.22 additional cost for RO
treatment, $0.22 for blended water
including deep-well water, and $0.30
for blended advanced treated water
without deep-well water.
Recommendations
1. Conduct toxicity testing to include a
short-term battery of tests and
long-term animal tests to further
evaluate the relative safety of re-
claimed wastewater as a source of
drinking water supply.
2. Conduct evaluations similar to
those reported here plus the above
recommended toxicity testing on
typical conventional water supplies
throughout the country to develop a
comparative evaluation of the
health risks associated with drink-
ing waters.
3. Identify compounds causing muta-
genicity response in the Ames test
following chlorination of reclaimed
wastewater to better evaluate their
health risks.
4. Evaluate the environmental signifi-
cance of alkylphenol polyethoxy
carboxylates that appeared to be-
come brominated upon chlorina-
tion.
5. Continue to develop qualitative and
quantitative information on the
organic residues in reclaimed
water.
The full report was submitted in partial
fulfillment of Cooperative Agreement No.
CS-806736 by the Orange County Water
District under the sponsorship of the U.S.
Environmental Protection Agency.
Perry L. McCarty, Martin Reinhard, Naomi L Goodman, James W. Gray don, and
Gary D. Hopkins are with Stanford University, Stanford, CA 943O5; Kristien E.
Mortelmans is with SRI International, Menlo Park, CA 94025; and David G. Argo
is with the Orange County Water District, Fountain Valley, CA 92708.
John N. English is the EPA Project Officer (see below).
The complete report, entitled "Advanced Treatment for Wastewater Reclamation
at Water Factory 21." (Order No. PB 84-148 857; Cost: $20.50, subject to
change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Municipal Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati. OH 45268
*U.S GOVERNMENT PRINTING OFFICE. 1984-759-015/7310
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
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