United States
Environmental Protection
Agency
Water Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S2-86/115 Apr. 1987
/it
&EPA Project Summary
Nitrate Removal from
Contaminated Water Supplies:
Volume I. Design and Initial
Performance of a Nitrate
Removal Plant
Gerald A. Guter
This report reviews the design, con-
struction, and operation of a 1-mgd
nitrate removal plant in McFarland,
California. The plant treats groundwater
pumped from one of the wells supplying
water for domestic use. Nitrates are
reduced from approximately 15.8 mg/L
NO3-N to well below the maximum
contaminant level (MCL) of mg/L
NO3-N. Included in the design con-
siderations are such factors as water
supply, health and safety, level of tech-
nology, location, capacity, regeneration
frequency, water quality, operational
sequence, brine disposal, automatic
operation, and performance monitoring.
The procedures for both manual and
automatic operation are discussed.
Continuous daily (24-hr) operation of
the plant was made possible by auto-
matic operation. The presence of the
operator is required for approximately
1 hr per day to check performance.
Automatic nitrate monitoring of product
water was performed once an hour
through the use of modified ion chro-
matography. Daily records of flows,
water quality, electrical consumption,
salt usage, and manhours were kept to
determine operating costs. The total
wastewater produced by the nitrate
plant was 3.39% of the amount of water
delivered to the distribution system from
the well. The treated water was 75% of
water delivered. Saturated brine was
0.09%, dilute brine was 0.49%, rinse
water was 1.76%, and backwash water
was 1.14%. All percentages were of
the blended water delivered to the dis-
tribution system. All waste from the
plant was discharged to the McFarland
municipal wastewater treatment sys-
tem, with ultimate discharge to 128
acres of cotton and alfalfa crops.
The amount of water treated by each
ion exchange vessel before regeneration
was 165,000 gal (260 bed volumes
(BV)). The amount of salt used per
regeneration was 6.35 Ib/ft3 of resin.
Capital costs totaled $311,118 for a
3-ft bed system, and $355,638 for a
5-ft bed system. Operation and main-
tenance costs were $0.13 per thousand
gal when the system was operating at 1
mgd. Total costs, including operations
and maintenance (O&M) and amortized
capital, were $0.25 per 1000 gal when
operating at design capacity of 1 mgd.
Thlf Profect Summary was developed
by EPA'* Water Engineering Reaearch
Laboratory, Cincinnati, OH, to announce
key finding* of the research project that
I* fully documented In a separate report
of the tame title (tee Protect Report
ordering Information at back).
Introduction
This report reviews the operation of a
1 -mgd nitrate removal plant at McFarland,
California. The plant and supporting
equipment are described, and an analysis
of the capital cost of construction and the
operation and maintenance (O&M) costs
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are also presented. The data on which
this report is based were obtained during
the initial adjustment period of the plant
and during the first 6 months of automatic
operation ending November 30,1984.
The plant uses the ion exchange pro-
cess with commercially available resin.
The process design is based on the re-
search and pilot studies performed under
a previous cooperative agreement with
the U.S. Environmental Protection Agency
(EPA). The design and operation of the
plant were supported by the McFarland
Mutual Water Co. (McFMWCo) and EPA
under cooperative agreement Nos.
CR808902-010 and CR808902-020.
Construction of the plant was made pos-
sible with funds from McFarland Mutual
Water Company, The Kern Co. Community
Development Agency, and the Kern
County Water Agency. The Community
Development Agency is funded by the
U.S. Department of Housing and Urban
Development (HUD).
This report is the first of a two-volume
final report under the existing grant and
is restricted to the general subject of the
initial operation of the plant. The second
volume will include a report on the con-
tinuing operation of the plant for several
additional months.
Plant Design
A flow diagram is shown in Figure 1.
Feed water is supplied directly from the
well pump into two of the vessels in the
service cycle. Vessel 1 is 50% exhausted
when Vessel 2 starts its service period.
When Vessels 1 and 2 are in service. No.
3 is in regeneration or standby. After No.
1 is exhausted, 2 and 3 are in service,
etc. Service is stopped in any one vessel
by an electrical signal from a flow totalizer
or by a manual signal.
Electrical conductivity is monitored at
well supply and product water locations
to detect any brine leakage into the pro-
duct water. Alarm and shut down occur if
product conductivity rises above that of
supply water. Nitrate levels are also
monitored in the blended product water
and excess nitrate can also cause auto-
matic alarm and shut down.
Major consideration was given to the
following elements of plant design:
Water Supply
Health and Safety
Level of Technology
Location
Capacity
Regeneration Frequency
Water Quality
Operational Sequence
Brine Disposal
Automatic Operation
Monitoring of Performance
Water Supply
The McFMWCo supplies water from its
well and through its distribution system
for municipal use. The only water source
at present is underlying groundwater. Six
wells are located in McFarland. Well No.
3 has been discontinued for public use
because of too high nitrate levels. Well
No. 2 is the location of th nitrate plant
now is operation. Recent analysis of Wells
1 and 4 shows nitrate above the maximum
contaminant level (MCL).
Table 1 presents data on the water
quality of four wells with high nitrate
levels. Because of recent projected de-
velopment trends, two new wells were
constructed to serve the developing areas
in a remote part of the City and operation
will begin shortly.
Health and Safety
Health and safety were the major con-
siderations; and therefore, they took
precedence where design conflicts arose.
The plant design was reviewed by the
California State Division of Health, which
issued an operating permit on May 13,
1983. Before issuing the permit, a design
review was conducted. The major con-
cerns were that:
1. Brine be isolated from the brine water
supply system (this is accomplished
with a double check valve).
2. Waste brine and wash water be
isolated from the distribution system
(this is accomplished by double valves
or a block and bleed arrangement).
3. Nitrate levels in supply water be kept
below 10 mg/L NO3-N and preferably
below 7 mg/L NO3-N.
4. A Class 2 State-certified operator be
made responsible for plant operation
(two employees of McMWCo will
quality for this certification).
Level of Technology
The technology used in the mechanical
design and planning for the plant relies
heavily on that used in the water soften-
ing industry. The chemical process design
is based on research on the use of anion
exchange resins completed under pre-
vious EPA grants. Although that research
indicated efficiency might be conven-
tional, commercial available strong-base
anion exchange resin was used as a
basis for design.
Location
Plant location at one of the well sites
was dictated by the already-in-place well
and distribution system, which have been
in use for more than 30 years and are
typical for small communities dependent
on groundwater. McFarland can draw
water from any of the six wells that
supply water to an interconnected dis-
tribution system. Because the system has
no central distribution point, the plant
had to be designed to operate from a
single well. Well pumps operate on a
demand basis; consequently, the plant
had to be able to operate in an automatic
on-off basis. The design was made to
accept water directly from the well pump,
treat it for nitrate removal, and allow
treated water to flow directly into the
distribution system without directing it to
a central part of the system and without
storage.
Capacity
The delivery capacity of Well No. 2 is
approximately 695 gpm (1 mgd on a
continuous basis). With nitrate-nitrogen
levels in the 16-mg/L range, a 7-mg/L
product can be achieved by reducing
nitrate to 0 in 70% of the water anc
blending with untreated water. Studies
show a decreased regeneration efficiency
as nitrate leakage in treated water ap
proaches zero.
The plant was sized to treat the tola
well production rate, to provide a blendin<
facility to allow a range of treatment leve
from partial to complete, and to providi
sufficient capacity to meet rising nitrati
levels.
Regeneration Frequency
Anion exchange resins require regen
eration with a sodium chloride brine. Fo
uninterrupted service, it is necessary ti
have a standby regenerated bed of resii
in a second vessel starting intooperatioi
when the first starts its regeneratioi
cycle.
Regeneration times (about 120 min ii
McFarland) are fixed regardless of be<
size, whereas bed exhaustion times o
service periods vary with bed size an
capacity (see Table 2). Bed exhaustioi
time should be longer than the regen
eration time if two beds are allowed.
Long standby periods require large
beds and added resin inventory an
equipment costs. Bed size is also limite
in that deeper beds give higher back
pressure and large area beds give lowt
flow rates (hydraulic loading), whic
promote reverse adsorption or dumpin
of nitrate from resin to product water.
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Ion Exchange System
Brine
I
to
0)
c
r
Pr
ressure Tank
J
7b Distribution
System
Figure 1. Flow diagram.
j \ (,J Valves
Legend
Service 1
Service 2
Regeneration
Table 1.
Item
Composition of McFarland Well Water (ppm) In 1980
Well No.
Date
Calcium
Sodium
Bicarbonate
Chloride
Sulfate
Nitrate-N
TDS
pH
5-8-80
28
50
88
28
51
6.8
235
7.7
4-9-80
88
65
102
86
105*
15.2
466
7.2
5-1-80
156
100
121
94
310
22.1
827
7.3
4-16-80
78
72
95
51
182
10.6
485
7.7
*Analyses on 5/31/78 showed sulfate levels of 261 ppm and nitrate levels of 78 ppm.
Table 2. Estimated No. of Regenerations per Vessel per Day
Percent Treated Water in Blend and Bed Depth
Bed Volumes
Treated
200
300
400
100%
3ft
2.67
2.00
1.33"
5ft
1.60
1.20
0.80+
75%
3ft
2.00
1.50
1.00
5ft
1.20
0.90
0.6
50%
3ft
1.34
1.00
0.67
5ft
0.84
0.60
0.40
25%
3ft
0.67
0.50
0.33
5ft
0.40
0.30
0.20
* Twelve-hour service period per vessel and 6-hr standby per vessel.
+ Twenty-hour service period per vessel and 10-hr standby per vessel.
Water Quality
Water quality is an extremely important
factor in nitrate ion exchange technology.
Two areas of concern are:
1. All major anions interfere to reduce
bed capacity and change product water
quality.
2. Resin ion equilibria and flow rate ef-
fects must be taken into consideration
to obtain proper bed operation.
Operational Sequence
The operational sequence is selected
either through a programmable controller
or manual push-button operation on each
vessel. Each vessel undergoes the fol-
lowing sequence:
Service, brine injection, brine displace-
ment, slow rinse, bachwash/resin de-
classification.
Under automatic control, any combina-
tion of valve operation can be selected in
one or more programs.
Brine Disposal
Brine is disposed to the municipal waste
treatment facility. Review by the City of
McFarland and the California State Water
-------
Quality Control Board was done through
the environmental impact report process.
The quality of dissolved solids added to
wastewater caused concern for its impact
on soil and groundwater in the disposal
area. Treated wastewater is discharged to
128 acres of agricultural land used for
growing animal feed and cotton.
A monitoring program is in effect in the
discharge area to monitor soil, ground-
water, and wastewater.
Automatic Operation
Automatic operation of the plant was
considered essential to reduce the
amount of manpower required to sustain
continuous operation. The only manual
operations required were turning the
system on or off and inspection of data
and plant operation.
Monitoring of Performance
Extensive plant monitoring was in-
corporated into the design because this
was a demonstration plant and it was
necessary to determine operating costs,
performance, and reliability. The methods
of flow and batch measurement presented
no difficulty; however, the method of
continuous nitrate monitoring was in
doubt because of the lack of reliable
methods. Ion chromatography was chosen
as the method for testing, since it ap-
peared adaptable to continuous nitrate
monitoring and had the capability of
monitoring other ions of interest. This is
also an approved EPA nitrate method.
Plant Performance
Salt Dosage Brine Use Factor
and Nitrate Leakage
If a Type I or II strong-base anion resin
is used, the amount of salt required for
regenerating a nitrate-spent bed can be
easily estimated from the chemical
analysis of water from Well 2 obtained in
January 1984. This estimate resulted in
the use of 1.5 BV of 6% salt as regenerant
to treat 165,900 gal for each service
cycle or 260 BV (N). This gives an ap-
proximate nitrate leakage of 6.3 mg/L
N03-N. Salt dosages were initially higher
than the target value of 1.5 BV of 6%
brine because of the inability of the brine
system to deliver a consistent brine
dosage. Consistent brine dosages were
obtained later by reprogramming to
terminate the batch on flow instead of
time. Table 3 compares the actual chemi-
cal data obtained over the 6-month period
with those estimated for a plant using a
260-BV service period.
Nitrate leakages obtained by the plant
are in good agreement with the predicted
values. Also, any failure to obtain proper
declassification will give an erroneous
nitrate analysis. The nitrate leakages in
Table 3 are from grab samples for certified
lab analyses and are subject to variations
of sampling and analytical errors.
The plant Brine Use Factor (BUF) values
(Table 4) are the average monthly values.
This data show that the plant is about 3%
less efficient than predicted. This result
is quite remarkable considering the as-
sumptions inherent in the method used
for making these predictions.
Dilute Brine Quantity
The quantities of both saturated and
diluted brine are given in Table 5 together
with other quantities used for each of the
6 months.
The amount of saturated brine is noted
to be approximately 0.09% of the total
water produced, or 0.12% of the amount
treated. The corresponding percentages
for diluted brine are 0.49% and 0.65%,
respectively.
Rinse, Water Backwash,
and Total Wastewater
The amounts of water used for rinsii
backwash, and total wastewater are lisl
in Table 5.
The plant automatically monitors cc
ductivity of rinse water. About 30% exec
rinse water is used because conductar
falls to a constant value at about 20
gal. Rinse water was not reduced duri
this period to allow excess rinsing.
The total wastewater over the 6-mor
period is 3.39% of the blended water a
4.52% of the treated water.
Total water recovery is 96.7% over 1
6-month period.
This high water recovery, which is ev
subject to improvement, is one of t
main advantages of the ion exchan
process over the reverse osmosis proce
for nitrate removal.
Power Consumption
Daily records of power consumption
the plant have been maintained to obtz
electrical power costs for well operati
and well plus nitrate plant operation. T
Table 3. Summary Comparison of Actual Chemical With Predicted Data
Plant Data
Estimated*
Date
6-84
7-84
8-84
9-84
10-84
11-84
Averages
Nitrate**
Leakage
2.9
3.2
2.3
0.7
2.9
3.8
2.6
Salt
Ib/ft3
5.94
6.36
6.46
6.48
6.35
6.55
6.35
BUF+
8.3
9.2
11.8
11.4
11.3
9.7
10.3
Nitrate**
Leakage
4.0
3.4
2.7
2.5
2.4
3.3
2.8
Salt
Ib/ft3
5.94
6.36
6.46
6.48
6.35
6.55
6.36
BUF
9.8
9.4
10.8
10.9
10.0
8.8
10.0
*For 260 BV service.
Equivalents of Chloride in Fresh Regenerant
+Brine Use Factor =
Equivalents of Nitrate Removed from Influent Water
^Concentration of nitrate listed as mg NO3-N/L
To convert to mg N03/L multiply by 4.43
Estimates of BUF for Full Bed Use and Partial Bed Use
BUF
Date
6-84
7-84
8-84
9-84
10-84
11-84
Average
260 BV
9.8
9.4
10.8
10.9
10.0
8.8
100% Use
8.9
8.1
8.9
8.5
7.3
7.4
Salt Dose (Ib/ft3)
260 BV
5.94
6.36
6.46
6.48
6.35
6.55
100% Use
5.94
6.36
6.46
6.48
6.35
6.55
% Brine Savings
Potential for
1OO% Bed Use
9.2
13.8
17.4
22.0
27.0
15.9
17.6
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Table 5. Secondary Plant Performance Factors
Thousands of
Gallons
Product Water
Date
6-84
7-84
8-84
9-84
10-84
11-84
Totals
% of Blend
% of Treated
Blend
5307
3595
3002
4245
4738
3771
24598
100
133
Treated
3516
2673
2617
3433
3055
3163
18457
75.0
100
Sat.
Brine
4044
3291
3272
4307
3752
4012
22678
0.09
0.12
Water Used, Gal
Dilute
Brine
37670
29270
7710
22300
16620
7190
120760
0.49
0.65
Rinse
Water
80990
68640
62340
77340
67360
77060
433730
1.76
2.35
Backwash
52422
44780
47640
57350
46130
31440
279762
1.14
1.52
Total
Waste
171082
142690
117690
156990
130110
1 15690
834252
3.39
4.52
pressure drop through the ion exchange
system is approximately 10 psi. Power
readings were taken with the well pump-
ing directly into the system and were
compared with readings taken while the
plant was in operation. Of the total power
consumed at the site, 10% was required
for the operation of the plant, yielding
0.244 kWh per 1000 gal as the power
requirement for plant operation. Power
for the brine pump and air compressor
are considered negligible.
The cost of this power obtained from
the billing of Pacific Gas and Electric Co.
is $0.08183 per kWh, making power cost
for plant operation $0.019967 per 1000
gal, or $19.97 per million gal of blended
water delivered to the system.
Cost Analyses
Capital costs for the McFarland plant
are summarized in Table 6. Costs are
given for two different vessel heights.
The 6-ft height accommodates the 3-ft
bed depth and the 10-ft height accom-
modates a 5-ft bed depth. The cost of the
extra side height is the most economical
way of increasing bed capacity. O&M
costs (Table 7) reflect actual salt and
power costs for the 6-month period. The
costs presented for normal plant main-
tenance, miscellaneous costs, and resin
replacement may be changed if firm data
on resin loss can be obtained. No loss of
resin capacity has been detected from
the operating data obtained thus far. The
1 -hr per day operator cost is still believed
to be adequate, since this is mainly a
record keeping and inspection effort.
Table 8 summarizes the total treatment
costs. The amortized annual capital cost
per 1000 gal is based on 100% use of the
1 -mgd capacity. The McFarland plant was
only operated at 13.7% of its full capacity
during this initial period (see Table 9). In
this case the amortized annual capital
cost per 1000 gal is 7.30 times that
shown in Table 8 or $.832 per 1000 gal.
As annual plant production falls from
100% to 0% of full capacity use, this cost
rises from $0.114 to infinity. O&M cost
per 1000 gal are estimated to remain
approximately as given in Table 7 regard-
less of plant usage. The high cost of
capital amortization of a partially used
plant must be taken into consideration
when assessing the cost impact on the
consumer. The true water cost that the
consumer must pay for operating the
plant at less than full capacity can be
estimated by comparing consumer costs
with and without the plant.
True consumer costs for this report
reflect the fact that the consumer receives
water from the plant as well as from
other wells in the system. In this case the
capital cost associated with water supply
capital costs in McFarland is the capital
cost of wells, the distribution system, and
related facilities and improvements (not
including a nitrate plant), CS, plus the
capital costs shown in Table 8, CP. The
total consumer cost of amortizing the
capital costs (per 1000 gal of water con-
sumed) by producing a fraction of 1 mgd
from existing facilities and the remainder
from the nitrate plant is:
Total capital cost/1000 gal = (CS + CP)/
1000 gal.
where: CS = cost of wells, distribution
system, related facilities,
improvements.
CP = capital costs for nitrate
plant.
The additional annual amortized capital
cost that the consumer must pay for
partial (or full) use of the nitrate plant is
the amortized capital cost, $41,773, for
the nitrate system as shown in Table 8.
The added cost due to O&M of the
nitrate plant during this report period is
0.137 times the O&M cost of Table 7.
The total added consumer cost during
this report period due to nitrate treatment
of 13.7% of the water supplied to the
system is:
$/1000 gal = $0.114 + 0.137 x $0.131
or $0.162
These cost analyses will be presented
in more detail when all costs over a 2-year
period of operation are available and will
be discussed in Volume II of this report.
Conclusions and
R ecommendations
1. The plant was automatically operated
for a 6-month period and exhibited
the following performance char-
acteristics averaged over the oper-
ating period:
a. Nitrate leakages averaged 5.2
mg/L N03-N (23.2 mg/L N03) in
a blend of treated and untreated
water.
b. The blend consisted of 76.1%
treated water and 23.9% un-
treated water.
c. Brine dosages were 6.36 Ib of
salt per ft3 of resin, or 2.49 per
1000 gal of blended water.
d. Brine efficiencies averaged 10.3
equivalents of chloride per equi-
valent of nitrate removed and
varied from a low of 8.3 to a high
of 11.8.
e. Water recovery was 96.7% of the
water pumped. The remaining
3.3% was discarded as waste
brine and wastewater.
f. Wastewater per 1000 gal of
blended watr consisted of 0.92
gal of saturated brine (4.9 gal of
dilute brine), 17.6 gal of rinse
water, and 11.4 gal of backwash
water.
2. Maximum automation was used
successfully to satisfy the minimal
manpower requirements of a small
water system operator. The plant
was designed and is being demon-
strated primarily with the needs of
small communities in mind where
wells and distribution systems are
already in place. The plant operates
at a well site rather than as a central
treatment plant.
3. Raw water composition varied during
this period of operation. Nitrates
varied from 16.0 to 11.1 mg/L
N03-N. This provided the opportunity
to measure the effect of changing
water composition on plant per-
formance.
4. Resin beds were operated at 76%
capacity during this initial adjust-
ment period to prevent overruns that
could occur because of operation
problems.
-------
Table ft Capital Costs for McFarland in 1983
Vessel Size
Item
I.X. Vessels (3 included)
Onsite construction
Brine tank
Other
Resin 225 ft3 (3 ft depth)
424 ft3 (5 ft depth)
Sub total
Engineering & administration 15%
Total
6'D x 6'H
$ 96,511
81,151
18,700
40,045
35,OOO
$271,407
40.711
$311.118
6'D x WH*
$111.741
81.154
18,700
40,045
56,610
$309,250
46.388
$355,638
* McFarland plant.
Table 7. Operation and Maintenance Costs
Item
Operation (1 hr/day)
Normal O&M. .02X(355,638)
Power, boost pump (.093/kWhj*
Resin replacement (5 yrs)
Salt ($31 .50/ton).
(7O% treated in blend f
Miscellaneous
Total O&M
Annual Cost
$ 4.745
7,113
7,289
1 1.522
14.314
3,000
$ 47.983
$/ 1000 gal
$ 0.013
0.019
0.020
0.032
0.034
0.008
$ 0. 131
*244 million gal based on. 08183C per kWh.
+2490 Ib/'million gal.
Table 8. Total Capital and O&M Costs
Item
Capital costs - $355.638 (20 years @ 10%)
Operation & maintenance
Total
Annual Cost
$41.773
47.983
$89.756
$/ 1000 gal
$0.114
0.131
$0.245
5. The effect of operating at less than
100% of the bed capacity is esti-
mated to be a decrease of brine
efficiency of approximately 18%.
6. Brine efficiency, nitrate leakage, and
bed volumes to nitrate breakthrough
can be accurately predicted from ion
exchange theory. Computer-based
programs being developed can simu-
late effluent histories and are com-
parable to those obtained from the
plant. They also give chromato-
graphic distributions of ions within
spent beds.
7. A 3-ft resin bed depth was used
during this period of operation. A 5-
ft bed will be used in future tests to
obtain comparative data.
8. The power consumed by the plant is
244 kWh per million gal of blended
water. This amount is 10% of the
total power required for pumping at
the well site.
9. Capital costs were $311,118 for a
plant with the 3-ft-deep resin bed
and $355,683 for a plant with a 5-ft
bed. The total costs are $0.245 per
1000 gal of blended water for the
5-ft bed plant (1983 costs). During
this report period the plant was
operated at only 13.7% capacity.
The overall cost to the McFarland
community for nitrate removal during
this period was $0.162 per 1000 gal
of water consumed.
10. The plant is totally automatic in
operation with automatic nitrate
analysis for monitoring and auto-
matic shut down if nitrate exceeds
the MCL in the product water. Com-
puter printouts of operating data are
obtained on a daily basis and if
alarms occur.
11. Operator tasks are reduced to ap-
proximately 1 hr per day and include
routine inspection, maintenance,
and recordkeeping.
12. Nitrate removal is economically and
technically feasible by the ion ex-
change process. The most undesir-
able feature is the production and
disposal of waste brine. At McFarland
during this report period, approxi-
mately 1300 Ib of waste salts were
disposed of in the plant wastewater
daily by discharging to the municipal
wastewater system. If the plant were
operated 24 hr per day, the daily salt
discharge would be 2500 Ib in
33,000 gal of wastewater. Close
monitoring of soil and plant condi-
tions at the disposal site is being
conducted.
13. Although nitrate removal by the ior
exchange process is largely being
considered as a process adaptable
for small communities, it is the lattei
who will find the waste disposa
problems the most difficult to solve
Improvements in the process ar€
still required to reduce quantities ol
waste salts. These can probably be
accomplished by use of highly selec-
tive nitrate resins, brine recircula-
tion, recovery and separation ol
sodium nitrate and sodium chloride,
and close adjustment of plant oper-
ation to changes in raw watei
composition.
14. Plant shut downs were due to mal-
functions of electrical and mechani-
cal equipment and leaks in plastic
pipe. All repairs were handled b\
water company personnel.
15. The adjustment and operation of the
plant was complex because the same
microprocessor was used for plam
control and data collection and re-
porting. Considerable operating time
was lost as a result of writing anc
testing the data collection portion o'
the program. The controller requirec
programming by ladder logic, which
is cumbersome as a computer lan-
guage. A separate computer is re-
commended for data collection at t
similar installation.
16. Ion chromatography is satisfactory
for routine anion analysis and re-
search, but it definitely requires im-
provement for continuous on-stream
plant monitoring. Additional re-
search on automatic nitrate analysis
is recommended.
17. Further development of the nitrate
selective resin is recommended be-
cause use of a nitrate selective resin
would eliminate the possibility of
nitrate dumping and would reduce
introduction of chloride into product
water.
18. Further research on waste brine
disposal and brine reuse is recom-
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mended to eliminate the buildup of
waste nitrate and other salts in the
disposal area and underlying ground
water.
The full report was submitted in ful-
fillment of Cooperative Agreement No.
CR808902-02-0 by McFarland Mutual
Water Company under the sponsorship
of the U.S. Environmental Protection
Agency.
Tab/e 9. Summary of Monthly Data
Salt Dose*
Date
6-84
7-84
8-84
9-84
10-84
11-84
Averages
Ib/ft3
5.94
6.36
6.46
6.48
6.35
6.55
6.36
Ib/ 1000 gal
of Blend
2.01
2.42
2.89
2.69
2.10
2.82
2.49
% Treated* Nitrate-N lOOOgal
in Blend (mg/L)* in Blend Delivered
66.2
74.0
87.2
80.9
64.5
83.8
76.1
4.8
5.0
5.6
5.3
5.4
5.2
5.2
5.307
3,595
3.002
4,245
4,738
3,771
*Monthly averages.
Gerald A. Outer is with Boyle Engineering Corporation, Bakersfiled, CA 93302-
0670.
Richard Lauch is the EPA Project Officer (see below).
The complete report, entitled "Nitrate Removal from Contaminated Water
Supplies: Volume I. Design and Initial Performance of a Nitrate Removal Plant,"
{Order No. PB 87-145 470/AS; Cost: $18.95, 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:
Water Engineering 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
BULK RATE
POSTAGE & FEES F
EPA
PERMIT No G-3
Official Business
Penalty for Private Use S300
EPA/600/S2-86/115
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