c/EFft
United States
Environmental Protection
Agency
Municipal Environmental
Research Laboratory
Cincinnati OH 45268
"
Research and Development
EPA-600/S2-84-061 Apr. 1984
Project Summary
Priority Pollutants in the Cedar
Creek Reclamation-Recharge
Facilities
Thomas D. Brisbin, Shin H. Ahn, Robert I. Foster, Stanley A. Labunski, and
James A. Oliva
The Cedar Creek Wastewater Recla-
mation Plant in Nassau County, NY, is a
0.24 mVs (5.5 mgd) advanced waste-
water treatment (AWT) plant designed
to produce a high quality effluent
suitable for groundwater recharge. The
Reclamation Plant was constructed as a
demonstration project under a U.S.
Environmental Protection Agency (EPA)
grant by additions and modifications
to the main 1.96 mVs (45 mgd) Cedar
Creek Water Pollution Control Plant.
Operation of the Reclamation Plant
began in April 1980, and groundwater
recharge operations began in October
1982.
This research project was initiated
with the overall objective of providing
preliminary data on the presence of
priority pollutants in the Cedar Creek
Wastewater Reclamation - Recharge
Facilities. The results indicate that 72
priority pollutants were identified in the
influent and that significant removals,
up to 99% of some individual compounds,
were achieved by the plant processes.
The data also indicate that the concen-
tration of trihalomethanes increases
during both the treatment and recharge
operations.
This Project Summary was developed
by EPA's Municipal Environmental
Research Laboratory, Cincinnati, Ohio,
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
To retard the contamination of the
Upper Glacial Aquifer and to protect the
remaining aquifers that provide Nassau
and Suffolk Counties with their sole
source of potable water supply, Nassau
County embarked upon a sewer program
in 1950 that, when completed in 1985,
will result in 85% of the county being
sewered. As part of this program, an
Environmental Impact Statement (EIS) on
Wastewater Treatment Facilities Con-
struction Grants for Nassau and Suffolk
Counties, New York, was completed in
1972. Adverse environmental effects
associated with the sewer program and
subsequent discharge of the treated
sewage effluent into Long Island Sound,
the South Shore Bays, and the Atlantic
Ocean could cause groundwater levels to
decline unless the decline is counterbal-
anced by groundwater recharge. The
declining groundwater levels could result
in: (1) decreased groundwater inflow to
streams, (2) declining levels of "water
table" lakes, (3) decreased subsurface
groundwater outflow to the bays and
Long Island Sound, and (4) salt-water
intrusion into the groundwater aquifers.
These declining groundwater levels could
cause increased salinity in some of Long
Island's estuaries and bays and, thus,
alter the ecosystems of these saline
water bodies.
As part of the EIS conclusions, it was
determined that: (1) the construction of
collection systems and effective waste-
water treatment facilities are essential to
protect the public water supply of Long
Island, and (2) as soon as the technology is
available, it would be advantageous for
Long Island to implement groundwater
recharge for the ultimate protection of its
water supply. A feasibility study on
advanced wastewater treatment and
groundwater recharge was completed
under an EPA grant in August 1973. The
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results of the feasibility study formed the
basis for the design and construction of
the 0.24 mVs (5.5 mgd) Cedar Creek
Wastewater Reclamation - Recharge
Facilities, which were placed in operation
in April 1980.
The specific objectives of the research
project reported herein were to: (1) deter-
mine individual treatment processes' and
overall reclamation plant performance for
the removal of priority pollutants, (2)
determine the transformation or genera-
tion of priority pollutants by the treatment
processes, and (3) determine the priority
pollutants present in the groundwater be-
fore and after recharge. It was acknow-
ledged during the planning period that
the number of samples would be minimal
and the results would be indicative rather
than deterministic. This approach was
acceptable because the facility was in its
initial stages of operation and the analyti-
cal results would indicate potential prob-
lems rather than provide statistical eval-
uations of performance and reliability.
Description of Reclamation
Plant and Recharge Facilities
The Reclamation Plant is an AWT plant
consisting of grit removal, chemically
aided primary clarification, suspended
growth nitrification/dentification, chemi-
cally aided sedimentation, dual-media
filtration, carbon adsorption and chlorine
disinfection (see Figure 1).
The basic approach taken for design of
the Reclamation Plant was to combine
incorporation of the best available techno-
logy in 1973 with the maximum use of
existing Cedar Creek Water Pollution
Control Plant facilities. Modifications to
existing facilities included the following:
(1) flocculation chambers were constructed
by installing a bulkhead, and horizontal
shaft, slow speed, turbine mixers in the
influent channel to two of the six existing
primary tanks; (2) 2 of the 12 existing
aeration tanks and 1 of the 8 final
clarifiers were used for combined carbon
oxidation-nitrification; (3) 2 aeration
tanks and a final clarifier were used for
denitrificaiton; (4) 2 aeration tanks and
the existing chlorine handling equipment
were used for disinfection; and (5)
existing solids handling facilities were
utilized. New processes and equipment
included: (1) rapid-mix basin and chemical
handling systems for lime slaking, ferric
chloride, polymer, and alum; (2) gravity
flow, mixed-media filters; (3) gravity flow,
granular activated carbon adsorbers; (4)
carbon regeneration furnace; and (5)
methanol feed system.
The effluent from the Reclamation
Plant is transported 10.1 km northwest of
the plant, via a 61.0-cm diameter (24 in.)
concrete-lined steel pipe, to the Cedar
Raw
Wastewater
r
Backwash
Waste
To Cedar Creek
Water Pollution
Control Plant
Grit
Removal
Waste
CCWF
#7
to ^ \
Lime
Mixing
% Si
*~
Sludge
CP*
imple Point
Primary
Sedimentation
k.
Alum and
Polymer
Methanol
Sedimentation
(Final Tank
No. 7)
Post
Aeration
Denitrification
Sedimentation
(Final Tank
No. 5)
Carbon
Oxidation-
Nitrification
Sludge
Waste to CCWPCP
Chlorine
i
I
Chlorination
#5
Effluent
Storage
fc Ove
WCCWP(
I
Backwashes
\Transmission Line
(10.1 km)
To Cedar Creek
Recharge Facilities
Figure 1. Cedar Creek wastewater reclamation plant.
2
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Creek Recharge Facilities in East Meadow,
New York.
The Recharge Facilities consist of
recharge basins, injection wells, a
storage reservoir, and associated equip-
ment required to recharge water from the
Reclamation Plant. Water to be recharged
is received into a 144 m3 central reservoir
from where it is distributed to the wells
and basins. The reservoir provides 0.17-
hr detention at the design flow rate of
0.24 m3/s. Pumping facilities are provided
in the Operations Building, along with a
sodium hypochloritefeed system that can
be used, if required, to control biological
activity in the recharge basins. Flow
rates, line pressures, and recharge water
quality are monitored and controlled at
this building. A schematic diagram of the
Recharge Facilities is presented in Figure
2.
Approach
The sampling and analysis program for
priority pollutants was divided into three
Well "E"
Well "D
phases. The first phase, conducted during
April, May, and June, 1981, was to
determine the overall performance of the
Reclamation Plant. The second phase,
conducted'during August, September,
and October, 1982, was designed to
investigate the performances of individual
Reclamation Plant processes. The third
phase involved analyzing samples taken
from monitoring wells at the recharge
facility site. These samples were collected
in May and October, 1982, to determine
the effect of recharge on groundwater
below the site. Over the project period, 37
samples were collected. The sample
locations are indicated schematically in
Figures 1 and 2.
Plant samples were 24-hour composites
started at intervals that compensated for
the detention times in the various
treatment units. This was done to
approximate the same water mass at
each location. Composite samples were
collected with the use of special, custom-
made, glass/Teflon composite samplers
designed to minimize loss or contamina-
tion of trace organic substances. The
samplers were operated at constant flow
rates, paral lei ing the constant flow rate of
the plant.
Observation wells sampled during the
third phase of this program were selected
on the basis of proximity to individual
recharge facilities and the direction and
depth of the recharged water flow. Four
observation wells were not sampled after
recharge because the recharged waste-
water had not yet reached these wells,
according to conductivity tests performed
by the U.S. Geological Survey. Observa-
tion wells were grab sampled.
Samples were analyzed for a total of
128 priority pollutants (asbestos was
excluded): 31 volatile organics, 47
base/neutral-extractable and 11 acid-
extractable organics, 25 pesticides/PCB's,
13 metals, and total cyanide. Analyses
were also performed to determine con-
From Cedar Creek
Wastewater
Reclamation Plant
i Sample Point(sj
Figure 2. Cedar Creek wastewater recharge facilities.
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centrations of nonpriority organic pollu-
tants.
Results
Overall Plant Performance
The Phase I investigation identified the
constituents present in the effluent to be
used for groundwater recharge and
evaluated the overall removal of priority
pollutants from the wastewater facility.
Seventy-two priority pollutants were
identified in the raw wastewater: 18
volatile, 23 base/neutral-extractable, and
6 acid-extractable organics; 15 chlorinated
hydrocarbons; and 10 heavy metals.
Thirty-five nonpriority pollutants were
also identified: 2 volatile organics, 28
extractable organics, 1 pesticide, and 4
heavy metals.
The analysis of overall plant perform-
ance indicated that the Reclamation Plant
provides the following removals of pri-
ority pollutants, based on total mass of
identified compounds:
Volatile organics
Extractable organics
Pesticides/PCB's
Metals
85%
80%
47%
64%
Some of the volatile compounds iden-
tified in the effluent, such as tri-
bromomethane, dibromochloromethane,
bromodichloromethane, and dichloro-
fluoromethane, appear to be formed
as a result of chlorination.
Unit Process Performance
The data collected in Phase II of the
project indicates that biological treatment
and post aeration are the major processes
responsible for removal of volatile
organics. Chemically aided primary
clarification and biological treatment
with alum and polymer addition are
almost equally important for the removal
of metals. Findings based on the total
pollutant mass at each sampling location
over the three sampling events indicate
that 41 % of the volatile organics were
removed through primary clarification and
that concentrations of these materials
were below detection limits after biological
treatment. Fifty percent of the heavy
metals were removed through primary
clarification, and biological treatment
increased the removal to 93%. Further
metals removal by filtration/carbon
adsorption appears to be negligible.
Six volatile organics were detected in
the carbon adsorber effluent during the
three Phase II sampling events. After
chlorination, however, 10 volatile organics
were detected in the chlorinated effluent.
Apparently several volatile organics
most notably, trihalomethanes(THM's)
were formed during chlorination. These
compounds were, in order of decreasing
concentration: bromoform, dibromochloro-
methane, chloroform, and bromodichloro-
methane.
The concentrations of bromoform and
dibromochloromethane were, in some
cases, higher than their maximum
discharge concentrations of 50 /ug/L, as
stipulated in the facility's State Pollutant
Discharge Elimination System (SPDES)
permit. Furthermore, during two of the
sampling events, total trihalomethane
(TTHM) concentrations were higher than
the maximum contaminant level of 100
/ug/L specified in the U.S. EPA's Interim
Drinking Water Standards.
The relationships between the forma-
tion of THM's, COD, chlorine dose,
residual chlorine, and pH were investigated
using the priority pollutant and plant
operating data. The data suggest a
combined effect of chlorine and organic
precursor presence, as measured by
COD, on the formation of THM's.
Effect of Recharge
During the Phase III testing program,
samples were collected from the six
monitoring wells before beginning the
recharge operations to determine the
baseline concentrations of priority pollu-
tants in the groundwater. Bis (2-ethyl-
hexyl) phthalate and seven volatile
organics were detected in monitoring
wells before recharge. These data are
shown in Table 1.
Although THM's were not detected in
any of the monitoring wells before
recharge, they were detected at significant
levels after recharge. TTHM concentra-
tions for the two well samples taken after
recharge were 256 and 258 /ug/L. These
Table 1. Effect of Recharge on Priority Pollutant Concentrations in Monitoring Wells at the Cedar Creek Recharge Facilities (fig/LJ
Well4B WellD6 Well 11B Well 11C Well12A Well 12B
Compound
Before After % Before After % Before After % Before After % Before After % Before After %
Rech. Rech. Chg. ftech. Rech. Chg, Rech. Rech. Chg. Rech, Rech. Chg. Rech. Rech. Chg. Rech. Rech. Chg.
Volatile Organics
Bromodichloromethane
Bromoform
Chloroform
Cis/Trans-1,2-
dichloroethene
Dibromochloromethane
1,1 Dichloroethane
1,1 Dichloroethene
Methylene Chloride
Tetrachloroethene
1,1,1- Trichloroethane
Trichloroethene
Jrichlorofluoromethane
Base/Neutral Extractables
Bis (2-ethylhexy/j phthalate
Metals
Copper
Lead
Zinc
BDL
BDL
BDL
BDL
6
BDL
BDL
20
9
63
20
3
20
BDL
BDL
BDL
230
BDL
BDL
BDL
600
*
55
33
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
43
10
BDL
8
49
#
BDL
BDL
80
BDL
BDL
BDL
BDL
BDL
BDL
BDL
19
*
BDL
*
50
BDL
*
34
124
*
BDL
98
BDL
BDL
BDL
BDL
BDL
BDL
BDL
(-1
I-)
(-1
>47
>eo
BDL
BDL
BDL
6
BDL
34
8
BDL
*
46
55
*
BDL
BDL
BDL
33 ()
110 (-)
BDL BDL
BDL
30 BDL >33 BDL
BDL BDL BDL
70 BDL >71 20
BDL BDL
BDL IIS
" BDL
BDL BDL
BDL
BDL
5
BDL
* BDL
BDL BDL
BDL BDL
BDL BDL
BDL BDL
BDL: Below detection limit
*: Detected, but /ess than a quantification limit of 10/jg/L
(-)' Pollutant concentration in the wells is higher after recharge than before recharge.
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vels are higher than the maximum
jntaminant level of 100 ug/L specified
in EPA's Interim Drinking Water Standards.
They are also at or above levels measured
in the Reclamation Plant Effluent.
An analysis of data at various points
along the recharge path (effluent storage,
transmission, percolation in the soil)
indicates that as detention time increases,
the concentrations of THM'salso increase.
Conclusions
The concentrations of the THM's
bromoform, chloroform, and dibro-
mochloromethane appear to increase
in the plant effluent after chlorina-
tion.
It is difficult to drawfirm conclusions
regarding unit process performance
for the removals of priority pollutants
because the number of samples
analyzed was small and many
compounds were below detection
levels. In a few cases, pollutant
concentrations in the effluent were
found to be higher than their
corresponding concentrations in the
influent, which resulted in large
variations in removal efficiencies.
The combined effect of high COD
concentration and high chlorine
dose appears to be significant with
respect to THM formation.
Observation well samples taken
after recharge demonstrate an
increase in TTHM concentrations in
the aquifer. Residual chlorine,
combined with organic carbon in the
recharge water and long detention
times, appear to be determining
factors.
Recommendations
Evaluate the formation of THM's in
the plant and recharge operations.
As part of this evaluation:
(a) optimize chlorine dose to reduce
residual chlorine levels;
(b) investigate the use of alternative
disinfectants, such as chlorine
dioxide or ozone;
(c) identify and reduce THM precur-
sors; and
(d) increase the organics removal
efficiency of the carbon adsorbers
by increased carbon regeneration
frequency or increased contact
time.
Use more sensitive analytical proto-
cols than standard EPA methods for
future investigations of unit process
removals of priority pollutants.
The full report was submitted in
fulfillment of Grant No. CR804654 by the
County of Nassau, NY, under the sponsor-
ship of U.S. Environmental Protection
Agency.
Thomas D. Brisbin. Shin H. Ahn. Robert I. Foster, and Stanley A. Labunskiare with
PRO Consoer Townsend Inc., Chicago, IL 60601; James A. Oliva is with
Nassau County, NY 11793.
John N. English is the EPA Project Officer (see below).
The complete report, entitled "Priority Pollutants in the Cedar Creek Wastewater
Reclamation-Recharge Facilities," (Order No. PB 84-159 904; Cost: $11.50,
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
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
4 U.S. GOVERNMENT PRINTING OFFICE: 1984-759-102/
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