United States
Environmental Protection
Agency
Water Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S2-85/112 Jan. 1986
SER& Project Summary
Point-Of-Use Treatment to
Control Organic and Inorganic
Contaminants in Drinking
Water
Gordon E. Bellen, Marc Anderson, and Randy A. Gottler
Several communities using point-of-
use (POU) treatment technology for
drinking water contaminant removal
were studied under a cooperative
agreement between the U.S. Environ-
mental Protection Agency (EPA) and
the National Sanitation Foundation
(NSF). Study sites included communi-
ties in Pennsylvania and New Jersey
using POU activated carbon devices for
reduction of volatile halogenated or-
ganics; Arizona and Illinois communi-
ties using POU activated alumina
devices for fluoride reduction; and an
Illinois community using POU reverse
osmosis devices for fluoride and dis-
solved solids reduction. In addition,
central treatment with activated alu-
mina for fluoride reduction was evalu-
ated at two operating plants in Arizona.
At all locations, POU devices pro-
vided effective treatment for several
months of operation. Average esti-
mated monthly costs per site for pur-
chase, installation, and maintenance of
treatment devices ranged from $4.25 to
$6.23 for activated alumina and acti-
vated carbon treatment, and were
$12.48 for reverse osmosis. Although
most POU installations operated with-
out problems from the time of installa-
tion, a few devices required unplanned
service. Management of POU devices is
necessary to ensure ongoing, effective
treatment.
This Project Summary was devel-
oped by EPA's Water Engineering Re-
search Laboratory, Cincinnati, OH, to
announce key findings of research
projects that are fully documented in
three separate reports: "Defluoridation
of Drinking Water in Small Communi-
ties" {EPA/600/2-85/110). "Point-Of-Use
Reduction of Volatile Halogenated
Organics in Drinking Water" (EPA/600/
2-85/109), and "Management of Point-
Of-Use Drinking Water Treatment Sys-
tems" (EPA/600/2-85/111} (see Project
Report ordering information at back).
Introduction
Small communities with contami-
nated drinking water supplies often lack
the financial resources and technical ex-
pertise to effectively deal with the prob-
lem. High initial capital costs can pro-
hibit construction of a central treatment
system for contaminant removal in
many cases. Constructing a new well or
connecting to a neighboring water sup-
ply may not be feasible. One alternative
solution is treatment of contaminated
water at the point-of-use (POU).
Although POU treatment may present
an efficient, cost effective solution to
drinking water contamination, there
may be potential problems associated
with losing the level of control associ-
ated with central treatment systems.
When POU treatment is the selected al-
ternative, a sound program for manage-
ment of POU drinking water treatment
systems is necessary to ensure that all
sites receive the desired quality of drink-
ing water.
Procedures
POU treatment was studied in several
communities by monitoring existing in-
stallations or by installing and monitor-
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»ti
ing new devices. All POU study sites
used a form of the line-bypass approach
to treatment. Line-bypass devices are
designed to treat only water intended
for consumption. With this approach,
the cold water line is tapped to provide
influent to a treatment device. A sepa-
rate tap for treated water is provided at
the sink.
Site selection was based on commu-
nity interest, quality of source water, lo-
gistics for water sampling, and the ap-
proach to treatment. POU devices were
purchased from equipment manufac-
turers or distributors and installed by
licensed plumbing contractors. Water
sample collectors were selected and
trained by NSF. Collection, preserva-
tion, and analysis of water samples
were in accordance with prescribed EPA
methods.
Bacteriological quality of predevice
and postdevice water was monitored at
all POU sites with Standard Plate
Counts (SPCs) and coliform enumera-
tion. To simulate water that would be
consumed if the faucet were not al-
lowed to run before water was drawn,
samples were collected from unflushed,
undisinfected taps. For comparative
purposes, samples were collected from
disinfected taps that were flushed for 2
to 3 min. In some cases, samples were
also collected from taps that were
flushed for 1L.
Cost information for POU treatment
in the Illinois and Pennsylvania commu-
nities was based on actual cost data col-
lected during the project. Cost data from
other sites were supplied by equipment
manufacturers and/or municipalities.
Maintenance costs for POU devices
were calculated using manufacturers'
rated service volumes and the average
volume of treated water.
In the Village of Silverdale, PA, 49
POU activated carbon (AC) devices, rep-
resenting products from several manu-
facturers, were installed and monitored
for 14 months of operation for control of
volatile organic chemicals (VOCs), most
notably trichloroethylene (TCE) and tet-
rachloroethylene (PCE). In the Lake
Telemark subdivision of Rockaway
Township, NJ, the township health de-
partment and a manufacturer of POU
AC devices began a pilot demonstration
in 1981 by installing and monitoring
devices in 12 homes with wells contam-
inated with organics. Performance veri-
fication and review of cost data were
included in this study.
Arizona communities using POU acti-
vated alumina (AA) devices for fluoride
reduction included Thunderbird Farms
and Papago Butte Ranches, where sepa-
rate distribution systems are provided
for irrigation and domestic water. A por-
tion of the domestic water is bypassed
and treated with AA for potable uses.
Domestic water boards for both com-
munities provide installation, monitor-
ing, and maintenance of treatment
devices. POU treatment with AA for ar-
senic and/or fluoride reduction was
studied at two Arizona institutions, the
Ruth Fisher Elementary School located
near Tonopah and the You & I Trailer
Park located new Wintersburg.
At the three Illinois project sites, the
public water systems are supplied by
well water with high fluoride, alkalinity,
and dissolved solids. Project demon-
strations included installation and mon-
itoring of 10 POU AA devices in Parkers-
burg and 40 POU AA devices in Bureau
Junction. In Emington, 47 low-pressure
POU reverse osmosis (RO) devices were
installed and monitored for 8 mo. These
sites were the first applications of POU
fluoride reduction at the community
level in Illinois.
Central AA treatment plants, located
at Gila Bend and Palo Verde, AZ, pro-
vided a basis for comparison of two
small, but different sized, central facili-
ties. The Gila Bend plant has been oper-
ating since May 1978; the Palo Verde
plant has been operating since Decem-
ber 1979. In addition, a pilot study was
performed in North Myrtle Beach, SC, to
estimate AA central treatment costs. A
•summary of all project sites appears in
Table 1.
Table 1. Site Summary
Results and Discussion
Volatile Halogenated Organics
Reduction
The major VOCs in Silverdale's water
supply were TCE and PCE. POU devices
reduced concentrations of these con-
taminants to nondetectable levels
(<0.001 mg/L) in 87 percent of the sam-
ples collected over 14 mo. The mean
volume treated during this period was
340 gal; maximum volume treated was
1130 gal. Devices were still in operation
at the end of the study.
Breakthrough, defined as detection of
the same VOC in consecutive post-
device samples from the same site at
concentrations above 0.001 mg/L, did
not occur for any device for TCE or PCE
during 14 mo of sampling. However,
trace concentrations of VOCs were de-
tected intermittently in postdevice sam-
ples from each model type; concentra-
tions were generally below 0.005 mg/L.
The most frequently measured post-
device VOC was chloroform. Although
the mean influent chloroform concen-
tration was 12 times less than the mean
TCE concentration, chloroform may
break through before TCE. This is sup-
ported by isotherm data typical for acti-
vated carbon.
The capital cost for POU AC treatment
in Silverdale ($289) was an average cost
of purchasing devices from several
manufacturers (in quantity) and equip-
ping them with product water meters.
Maintenance costs included an average
monthly repair cost per site of $1.43.
Some POU devices required no mainte-
nance during the study.
In the Lake Telemark subdivision of
Rockaway Township, 12 POU AC
devices were installed on private well
Site
Gila Bend, AZ
Palo Verde, AZ
North Myrtle Beach, SC
Thunderbird Farms, AZ
Papago Butte, AZ
Ruth Fisher School, AZ
You & 1 Trailer Park, AZ
Parkersburg, IL
Bureau Junction, IL
Emington, IL
Silverdale, PA
Rockaway Township, NJ
Treatment
Approach
Central
Central
Central
POU
POU
POU
POU
POU
POU
POU
POU
POU
Treatment
Process
AA
AA
AA
AA
AA
AA
AA
AA
AA
RO
AC
AC
Application
Fluoride Reduction
Fluoride Reduction
Cost Estimate for
Fluoride Reduction
Fluoride Reduction
Fluoride Reduction
Fluoride Reduction
Fluoride & Arsenic
Reduction
Fluoride Reduction
Fluoride Reduction
Fluoride & Dissolved
Solids Reduction
Organics Reduction
Organics Reduction
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water supplies in October 1981. Only
one of 21 postdevice samples collected
from October 1982 through October
1983 contained detectable VOCs (0.004
mg/L TCE and 0.002 mg/L PCE). Eight
sites were sampled during the 24th
month of operation with no detectable
VOCs in effluent samples. After 2 yr of
service, the average cumulative volume
treated was approximately 1650 gal,
based on readings taken from a flow in-
dicator on the device. A device sampled
after reaching its estimated treatment
capacity of 2000 gal produced water
with no detectable VOCs.
Equipment costs of POU AC devices
in Rockaway ($225) were negotiated by
the community during an initial phase
of the pilot demonstration. No mainte-
nance was reported during the 2-yr pilot
demonstration period. A summary of
results from demonstrations of POU AC
devices in Silverdale and Rockaway
Township appears in Table 2.
Activated Alumina
Defluoridation
Several treatment runs from the AA
central treatment plants were evaluated
by collecting and analyzing water sam-
ples and by reviewing plant records.
Fluoride exchange capacities ranged
between 1840 and 2600 grains/ft3 (4210-
5950 grams/m3) for Gila Bend and be-
tween 2260 and 3540 grains/ft3 (5170-
7890 grams/m3) for Palo Verde. Average
media attrition rates per regeneration
were 1.2 percent of bed volume for Gila
Bend and 2.8 percent for Palo Verde.
Most media attrition appeared to occur
during regeneration.
Although the plant at Palo Verde
demonstrated higher fluoride exchange
capacity than at Gila Bend, operating
costs were also higher. Central treat-
ment production costs (amortized capi-
tal costs plus operating costs) per 1000
gal were $0.45 for Gila Bend and $5.37
for Palo Verde. Higher chemical con-
sumption rates (i.e., stronger regener-
ant) and very low production con-
tributed to the higher cost. The use of
part-time, inexperienced operators at
Palo Verde resulted in inefficient opera-
tion at times.
At North Myrtle Beach, a pilot demon-.
stration was performed to develop a
cost estimate for construction and oper-
ation of central treatment facilities. Be-
cause North Myrtle Beach's water sup-
ply consists of 10 wells in dispersed
locations, the proposed system was a
Table 2. POU Activated Carbon Studies
Participating Sites
Service Area Type
Mean Treated Water Use (gpd)
Trichloroethylene (mean mg/L) 1
Predevice
Postdevice
1,1,1-Trichloroethane (mean mg/L)1
Predevice
Postdevice
Costs
Capital ($)2
To Customer ($/month)3
Silverdale, PA
49
central system
with single
family homes
1.0
0.080
<0.007
0.007
<0.007
289
5.98
Rockaway Township, NJ
12
private wells
at single
family homes
2.3 est.
0.125
<0.001
0.092
<0.007
255
4.23
^Samples containing <0.001 mg/L were assigned a value of 0.0009 mg/L for calculation of
the mean.
2Average of five manufacturers; includes equipment + installation costs.
3Capital, amortized at 10% for 20 years + maintenance.
group of 10 small (200,000 gpd) central
plants. Estimated production costs were
$0.57 per 1000 gal.
At Thunderbird Farms, several POU
AA devices reduced influent fluoride
levels effectively for periods exceeding
2 yr. Other AA devices operating at
Thunderbird Farms had shorter service
lives, attributed to media cementing
and/or short-circuiting. At the You & I
Trailer Park, raw water fluoride concen-
tration was 15.7 mg/L and arsenic was
0.086 mg/L. A POU AA device effectively
treated 2500 gal (330 bed volumes) be-
fore fluoride breakthrough, demonstrat-
ing the highest exchange capacity
observed for POU devices (2300 grains/
ft3). Influent arsenic and silica concen-
trations at Arizona POU sites generally
were reduced to nondetectable levels
beyond fluoride breakthrough.
POU AA devices installed in Parkers-
burg and Bureau Junction were
equipped with valves; this allowed par-
tial bypassing of raw water to provide
optimal fluoride concentrations by
blending treated and untreated water.
Valve settings were controlled with a
colorimetric test kit during sample col-
lection.
The effect of raw water alkalinity is
demonstrated in the data from Illinois
sites, which included a pilot demonstra-
tion in Emington. The higher alkalinity
at Parkersburg caused fluoride break-
through at a lower mean cumulative
bed volume (110 bed volumes) than at
Emington (190 bed volumes). Break-
through at Bureau Junction, with the
lowest alkalinity, was not observed until
350 bed volumes. Part of the reduced
capacity at Emington must be attributed
to the accelerated flow (370 gpd) during
the pilot study.
Maintenance costs for POU AA
devices were based on replacing the
alumina cartridge when treated water
fluoride levels reached the local Maxi-
mum Contaminant Level (MCL). For Ari-
zona, the MCL was 1.4 mg/L, and for the
Illinois communities, it was 1.8-2.0 mg/
L. Summaries of results from Arizona
and Illinois POU AA sites appear in
Table 3 and Table 4, respectively.
Low-Pressure Reverse Osmosis
POU RO systems installed in Eming-
ton used a spiral-wound polyamide RO
membrane operated at line pressure.
Pretreatment included granular acti-
vated carbon (GAC) followed by a 5-|A
prefilter. Product water was stored in a
2-gal pressurized tank. Reject water was
bled through a capillary tube to the
home drain line. Product water from the
storage tank passed through a GAC pol-
isher before being dispensed.
Fluoride rejection averaged 86 per-
cent, with total dissolved solids rejec-
tion (TDS) averaging 79 percent. Rela-
tively large ranges of rejection
percentages were observed for all ana-
lytes. This phenomenon did not corre-
late with site, use rate, or collection
date, but appeared to be due in part to a
pressure drop across the prefilter as-
sembly. Flow rates were measured for
several RO devices during a site visit.
Ranges of product and reject flow rates
were 1.3 to 4.4 gpd and 16.1 to 27.8 gpd,
respectively. Water temperatures and
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pressures (measured at hose connec-
tions) did not correlate with flow rates.
Iron deposits in the well and distribution
system fouled some GAC prefilters, cre-
ating head loss across the pretreatment
assembly. One GAC prefilter which had
been fouled with iron deposits was re-
moved, flushed, and reinstalled. The
resulting 33 percent production rate
increase was accompanied by a
29 percent increase in solids rejection,
implying a constant flux of solids across
the RO membrane, i.e., more water was
produced for essentially the same mass
of solids, resulting in higher quality
water.
The capital cost for POU RO at Eming-
ton ($540) was an average of several
manufacturers' quotes for devices, with
and without pressurizing pumps, based
on purchase of 40 to 50 units. The aver-
age installation cost per unit of $68 (per-
formed by an equipment dealer) was in-
cluded.
Costs for central RO treatment at Em-
ington were estimated by soliciting a
quote; they included approximately
$60,000 for a central RO system (includ-
ing mechanical and electrical installa-
tion) and $60,000 for a concrete block
building. Estimated operating costs per
1000 gal of product water included
chemicals ($0.10), power for pumps
($0.36), membrane replacement every
5 yr ($0.18), and prefilter cartridge re-
placement ($0.02). Monthly customer
costs were based on the design flow of
16,500 gpd. A summary of the Emington
RO demonstration appears in Table 5.
Bacteriological Sample Results
Standard Plate Counts (SPCs) from
the AC sites indicated microbial colo-
nization of the carbon bed. In Silverdale,
unflushed postdevice samples had
mean densities two orders of magni-
tude higher than corresponding pre-
device samples. If 1L of water was
flushed from the line before sampling,
postdevice samples had mean densities
only one order of magnitude higher
than predevice samples. Samples of
water collected after 2 min of flushing
had SPC densities comparable to sam-
ples of water from the distribution sys-
tem. In Rockaway, flushing and disin-
fecting the tap reduced SPCs by one
order of magnitude. Data collected dur-
ing the study did not indicate coloniza-
tion of AC devices by coliform orga-
nisms. Positive coliform results in
Silverdale were obtained from 4 of 176
postdevice samples collected from
flushed, disinfected taps. Postdevice re-
Table 3. Arizona POU Activated Alumina Studies
Participating Sites
Service Area Type
Influent Fluoride (mg/L)
Influent Alkalinity (mg/L as CaCO3)
Mean Treated Water Use (gpd)
Volume to Breakthrough1
(gallons)
(bed volumes)
Costs
Capital ($)
To Customer ($/month)2
Thunderbird
Farms
8
central system
with single
family homes
2.6
200
1.4
>1540
>4W
225
4.44
Papago
Butte
1
subsystem
for several
families
2.6
200
18.5
9500
1270
350
4.60
Ruth Fisher
School
1
institution
4.4
80
8.5
WOO
270
360
12.00
You&l
Trailer Park
1
institution
75.7
40
5.5
2500
330
230
6.27
1 Defined as the point where postdevice fluoride concentration reached the local MCL.
2Capital, amortized at 10% for 20 years + maintenance.
Table 4. Illinois POU Activated Alumina Studies
Parkersburg
Participating Sites
Service Area Type
Influent Fluoride (mg/L)
Influent Alkalinity (mg/L as CaCO3)
Mean Treated Water Use (gpd)
Volume to Breakthrough1
(gallons)
(bed volumes)
Costs
Capital ($)
To Customer ($/month)2
10
central system
with single
family homes
6.6
1000
0.6
400
110
273
6.23
Bureau Junction
40
central system
with single
family homes
6.0
540
0.8
1300
350
285
4.25
Emington
1
pilot
study
4.5
880
370
700
190
273 est.
5.38 est.
1 Defined as the point where postdevice fluoride concentration reached the local MCL.
2Capital, amortized 10% for 20 years + maintenance.
Table 5. Emington, Illinois, POU Reverse Osmosis Study
Participating Sites
Service Area Type
Mean Treated Water Use (gpd)
Mean Flow Rates (gpd)
Product Water
Reject Water
Fluoride (mean mg/L)
Predevice
Postdevice
Total Dissolved Solids (mean mg/L)
Predevice
Postdevice
POU Treatment Costs
Capital ($)1
To Customer ($/month)2
Estimated Central Treatment Costs
Capital ($)
To Customer ($/month)2
47
central system
with single
family homes
0.8
2.9
22.5
4.5
0.6
2530
520
540
12.48
122,000
28.80
1 Average of six manufacturers; includes equipment + installation costs.
2Capital, amortized at 10% for 20 years + maintenance.
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samples were negative for coliform or-
ganisms. No conforms were detected in
postdevice samples collected in Rock-
away.
Bacteriological samples collected at
AA POU sites indicated microbial colo-
nization of the alumina bed, though not
as great as with activated carbon. At the
Arizona sites, slight increases in SPCs
through AA devices Were observed.
Flushing reduced SPCs by a small mar-
gin. No coliforms were detected in Ari-
zona AA postdevice samples. In Bureau
Junction, postdevice SPCs were highest
when devices were first placed in opera-
tion, and decreased with use. There was
no evidence of colonization of AA
devices by coliform organisms. Out of
153 samples, coliforms were detected in
9 predevice samples and 4 postdevice
samples. One unit maintained consis-
tent positive coliform results and was
removed from service. Resamples from
other units were negative for coliforms.
In Parkersburg, postdevice SPCs were
highest when no influent chlorine resid-
ual was detected. Flushing and disin-
fecting taps reduced postdevice SPCs
by an order of magnitude. No coliforms
were detected in 80 Parkersburg post-
device samples.
SPC results from Emington (RO & AC)
demonstrated an order of magnitude in-
crease through the treatment system.
Limited sampling from stages in the RO
& AC system indicated that most bacte-
rial growth was occurring in the AC pol-
isher. Of 92 samples, coliforms were de-
tected in 4 predevice and 11 postdevice
samples. One site was resampled twice
before postdevice samples were clear,
and another site required disinfection of
the RO system twice before resamples
were acceptable. Resamples from other
units were acceptable.
Summary and Conclusions
Both central and POU AA treatment
are effective in reducing fluoride levels
in otherwise potable water. POU treat-
ment with AA appears to be cost com-
petitive with central treatment for com-
munities having 330 to 710 service
connections. Raw water quality (i.e., al-
kalinity) and water comsumption deter-
mine the operational life of the POU AA
device and have significant impact on
costs. Low-pressure POU RO treatment
was effective in reducing fluoride and
total dissolved solids from a brackish
groundwater supply. POU AC treatment
devices effectively reduced concentra-
tions of trichloroethylene, tetra-
chloroethylene, carbon tetrachloride,
1,1,1-trichloroethane, 1,1-dichloro-
ethylene, 1,1-dichloroethane, and chlo-
roform at influent concentrations
studied.
Monitoring is required to ensure con-
sistent performance on a community
level. For AA devices, monitoring may
be accomplished with field tests. For
VOC reduction in most cases, it is more
cost effective to replace AC cartridges
prematurely than to pay for frequent
analysis. For this method to be effective,
relatively consistent source water qual-
ity is required.
Microorganisms, measured by the
standard plate count method, were
present in higher numbers in post-
device water than in predevice water.
Variation of sampling techniques for
collecting bacteriological samples from
POU devices significantly affected re-
sults. Flushing taps can significantly im-
prove bacteriological quality. The oc-
currence of coliforms in postdevice
samples appeared to be associated with
the bacteriological quality of the source
water.
Recommendations
A sound program for management of
POU treatment systems is necessary to
ensure that the desired level of treat-
ment is provided to all sites, that pre-
scribed monitoring and maintenance
are carried out, and that the system is in
compliance with applicable regulations.
This may be accomplished through for-
mation of a water quality district, an in-
dependent corporate body. The district
obtains funding, incurs costs, and as-
sumes responsibility for the treatment
system. The district may resemble ex-
isting districts created for water supply,
wastewater discharge, or solid waste
disposal. For POU treatment to be con-
sidered as a means of compliance with
regulations, regulatory agencies may
require the establishment of a clearly
defined body to assume responsibility
for the system. Formation of an offi-
cially sanctioned district may also open
avenues for funding not otherwise
available. The basic management func-
tions of a water quality district include
determination of the best treatment ap-
proach, equipment selection, coordina-
tion of equipment installation, monitor-
ing and maintenance, district admin-
istration, and education and public noti-
fication.
The full reports were submitted in
partial fulfillment of Cooperative Agree-
ment R809248 by the National Sanita-
tion Foundation under the sponsorship
of the U.S. Environmental Protection
Agency.
U. S. GOVERNMENT PRINTING OFFICE: 1986/646-116/20762
-------
Gordon E. Bellen, Marc Anderson, and Randy A. Cottier are with the National
Sanitation Foundation, Ann Arbor, Ml 48106.
Steven Hathaway is the EPA Project Officer (see below).
This Project Summary covers three separate reports, entitled:
"Point-of-Use Reduction of Volatile Halogenated Organics in Drinking
Water,"(Order No. PB 86-107 711/AS; Cost: $11.95)
"Defluoridation of Drinking Water in Small Communities," (Order No. PB
86-109 337/AS; Cost: $16.95)
"Management of Point-of-Use Drinking Water Treatment Systems." (Order
No. PB 86-105 285/AS; Cost: $11.95)
The above reports will be available only from: (cost subject to change)
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Water Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S2-85/112
0000329 PS
U S ENVIR PROTECTION AGENCY
REGION 5 LI8R*RY
230 S DEARBORN STREET
CHICAGO It 60604
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