EPA-440/3-77-022
March 1978
JOINT MUNICIPAL/INDUSTRIAL
LAND APPLICATION AND
WASTEWATER REUSE SYSTEM
U.S. ENVIRONMENTAL PROTECTION AGENCY
* Environmental Research Information Center* Technology Transfer
* Office of Water Planning and Standards • Water Planning Division (WH 554)
401 "M" St. S.W., Washington, D.C. 20460
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ACKNOWLEDGEMENTS
This publication contains information prepared for the U.S.
Environmental Protection Agency, Environmental Research Infor-
mation Center, Office of Research and Development; and Water
Planning Division, Office of Water Planning and Standards.
The information in this publication was prepared by Wiggins-
Rimer & Associates, Durham, North Carolina. The case history
was authored by Mr. Roger N. Schecter, AIP, under the general
direction of Mr. Alan E. Rimer, P.E. Also providing assistance were
Mr. Al Hancock, 208 Project Director of the Southeast Idaho Coun-
cil, Mr. John C. Postlewait, Public Works Director for the City of
Pocatello, Mr. J.F. Cochran, Director of Environmental Engineering
for J.R. Simplot Company, and Dr. Klane F. Forsgren of Forsgren,
Perkins and Associates.
NOTICE
This publication has been reviewed by the Environmental Research Information Center and
the Water Planning Division, Office of Water Planning and Standards, U.S. Environmental Pro-
tection Agency, and is 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
any mention of trade names or commercial products constitute endorsement or recommendation
for use.
11
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JOINT MUNICIPAL/INDUSTRIAL
LAND APPLICATION AND WASTEWATER REUSE SYSTEM
A primary focus of the Southeast Idaho
Council of Governments (SICOG) areawide
water quality management program is on im-
proving the water quality of one of the major
streams in the planning area - the Portneuf
River. In 1973, the State of Idaho ranked the
Portneuf River as 13th on a priority list of
125 streams needing water quality improve-
ment. Within a half-mile stretch northwest of
the City of Pocatello, three point source dis-
charges are added to the River. The three dis-
chargers, one municipality and two manufac-
turing plants, are not fully meeting some
values in their respective National Pollutant
Discharge Elimination System (NPDES)
permits. Because Pocatello had upgraded its
wastewater treatment plant to include second-
ary treatment in 1972, a 201 facilities grant
was not being pursued. Operational problems
were, however, resulting in high BOD being
discharged to the river. In addition, the J.R.
Simplot Company, a fertilizer manufacturing
plant, had very high nutrient concentrations
in its effluent, and FMC Corporation was
exceeding permit values for temperature.
As part of its areawide water quality pro-
gram, SICOG funded and was the primary
coordinating agency for the "Joint Waste-
water Treatment Feasibility Study." The City
of Pocatello, its consulting engineers, and
Simplot were primarily responsible for the
technical aspects of the study which sought to
identify for both the City and the industry the
best alternative for the treatment of combined
flows to meet "best practicable control tech-
nology." Physical-chemical treatment and
discharge, as well as land application alterna-
tives, were evaluated.
The study concluded that a land application
system for irrigation and utilization of nutri-
ents was the best alternative. The City of
Pocatello and Simplot are implementing the
selected alternative, and FMC Corporation has
decided to solve its temperature problems on
its own. Several advantages for the City and
Simplot were available in the selected plan.
The planning area is predominantly agricul-
tural, but because average annual precipitation
is only eleven inches, irrigation is a necessity.
PLANNING AREA
The Southeast Idaho Council of Govern-
ments' planning area is located in the south-
eastern portion of the State, bounded to the
south by Utah and to the east by Wyoming.
The six counties which comprise the regional
planning area are predominantly agricultural
and also contain fairly large tracts of National
Forest land. The SICOG Areawide agency,
shown in Figure 1, has water quality planning
responsibilities for the most populated area of
the region which includes Bannock and Caribou
Counties. The 1975 estimated population of
these counties was 63,958 with Bannock
County accounting for 88 percent of the total.
Pocatello, in Bannock County, is the largest
city in the region with a 1975 population of
42,560. The City has been growing at an
average rate of 8 percent per year over the last
five years.
The Portneuf River is the major surface
stream in the area. It originates in Caribou
County and flows through the City of Poca-
tello before discharging to the American Falls
Reservoir approximately eight miles north-
west of Pocatello. The annual precipitation in
the region is only eleven inches per year; there-
fore the River is used extensively for irrigation
during the summer growing season. Primary
crops raised are small grains, alfalfa hay, pota-
toes, and sugar beets. At times, the flow in
the middle reach of the river is very low be-
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I Franklin
Figure 1. Southeast Idaho Council of Governments Regional Planning Area.
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cause of the heavy irrigation demand. At the
reach just downstream of Pocatello, however,
several large springs increase flow in the river
by 100 cubic feet per second. Along this
reach the Pocatello wastewater treatment
plant and several industries discharge to the
River.
PROBLEM IDENTIFICATION
With the passage of the 1972 Water Pollu-
tion Control Act Amendments, Pocatello and
SICOG realized that municipal and industrial
wastewater discharges would eventually be
required to meet more stringent effluent stan-
dards. Pocatello had upgraded their municipal
wastewater plant to secondary treatment in
1972. However, SICOG recognized there were
still water quality problems in the Portneuf
River and therefore directed a major element
of their 208 Work Plan toward joint municipal
and industrial solutions to address water qual-
ity problems. The full SICOG areawide pro-
gram was approved and their comprehensive
water quality planning efforts were initiated in
July, 1975.
A working committee of the City, SICOG,
and the respective industries was formed and
a Feasibility Study was initiated in October,
1975. The basic premise of the Study was that
"best practicable control technology" would
be required for the municipal and industrial
discharges by 1977. Its expressed objective
was to determine the best alternative for the
treatment of combined wastewater from
Pocatello and the adjacent industries.
The problem of point source discharges and
their impact on the water quality of the Port-
neuf River has been a continuing concern for
the SICOG and the City of Pocatello. The
Portneuf River receives several point source
discharges in a half-mile stretch just down-
stream of the City. As shown in Figure 2, the
most significant dischargers are J.R. Simplot
Company (1.4 mgd), FMC Corporation (1.7
mgd), and the Pccatello Wastewater Treat-
ment Plant (6 mgd). The discharge of the
J.R. Simplot plant is high in nutrients, espe-
cially phosphorus, ammonia and organic nitro-
gen, as well as being high in fluorides. The
FMC Corporation, a manufacturer of ele-
mental phosphorus, discharges a heated efflu-
ent that, at times, exceeds the NPDES tem-
perature limitations. The Pocatello Waste-
water Treatment Plant (WWTP) marginally
.meets NPDES permit requirements.
The City recognized in 1969 that more
sophisticated waste treatment processes than
those in use at that time would be needed. In
an initial effort to prepare for this need, the
City passed a bond issue in 1970, which in-
cluded $100,000 for "advanced" water quality
control. The $100,000 was to be used for ter-
tiary treatment or a land disposal system if
preliminary studies indicated that such systems
would provide a feasible and cost-effective
solution. Preliminary studies conducted in
1970 and 1971 revealed that such alternatives
were neither feasible nor desirable at that
time. Therefore, the monies were not ex-
pended but kept for implementation of
possible future advanced water quality
control alternatives.
ESTABLISHING BASELINE CRITERIA
FOR THE PORTNEUF RIVER
The State of Idaho's anti-degradation guide-
lines require that the effluents be of a quality
sufficient to maintain the water quality of the
receiving stream. To avoid degradation of the
Portneuf River, the following goals are to be
maintained: BOD not to exceed 10 mg/1;
total dissolved solids not to exceed 400 mg/1;
total Kjeldahl nitrogen not to exceed 3.06
mg/1; and total phosphorus not to exceed 1.0
mg/1. Both the Portneuf River and the Ameri-
can Falls Reservoir are classified for full
body contact recreation with additional
standards for coliforms, dissolved oxygen,
pH, temperature, and turbidity.
Violations of NPDES permit requirements
for phosphorus, ammonia, nitrate, Kjeldahl
nitrogen, and fluoride were occurring at
Simplot; the Pocatello WWTP was exceeding
the permit value for BOD; and FMC, at times,
exceeded the discharge temperature require-
ment. Daily loadings and permit require-
ments for these discharges are shown in Table
1. These permits require that violations should
be corrected either by modification or im-
provement in treatment efficiencies.
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Table 1. - NPDES permit requirements and actual loadings (yearly averages)
Flow mgd
BOD5 Ib/day
SS Ib/day
P Ib/day
NH3-N Ib/day
N03-N Ib/day
TKN Ib/day
F Ib/day
Simplot plant
Permit
2.67
970
209
195
9
197
209
Actual
1.4
290
422
1400
90
1800
220
Pocatello plant
Permit
7.5
1875
1875
Actual
6.0
1900
1400
287
860
1150
39
EVALUATION OF ALTERNATIVE
WASTEWATER TREATMENT SYSTEMS
In evaluating the feasibility of joint treat-
ment systems, three primary alternatives
were studied:
• Treatment of municipal and industrial
discharges at the existing Pocatello
plant.
• Modification of the existing Pocatello
plant to provide physical-chemical
treatment.
• Individual treatment at the current level
and joint effluent disposal by land appli-
cation.
Detailed evaluations of these primary
alternatives were conducted, and the joint
land application system was determined to
be the best approach. Figure 3 summarizes
the primary decision criteria applied to the
evaluation, and the following paragraphs
briefly discuss the major considerations.
Treatment and Discharge Assessment
In evaluating the first alternative, the exist-
ing treatment efficiency of the Pocatello plant
was assessed on the basis of the percentage
removal of BOD, nitrogen, and phosphates
from the combined influent of Pocatello,
Simplot, and FMC. To meet the permit
values and the anti-degradation guidelines,
approximately 90 percent of the nutrients
needed to be removed. Because of the lack of
specific facilities at the existing plant for
nitrogen and phosphorus removal, the best
that could be accomplished without extensive
and costly plant modification was a 25 per-
cent removal of these nutrients. This
alternative was therefore abandoned.
The second treatment and discharge alter-
native focused on modifying the existing
Pocatello plant to provide for physical-
chemical tertiary treatment. Four sub-
alternatives were considered as providing the
necessary tertiary level of treatment:
System I. Lime treatment + filtration +
activated carbon + ion ex-
change + nitrification + deni-
trification + chlorination.
System II. Same as I, but excluding ion
exchange and adding am-
monia stripping.
System III. Same as I, but excluding
activated carbon.
System IV. Same as II, but excluding
activated carbon.
Each treatment system was designed to
meet the prescribed water quality standards
and the required nutrient removal. Capital
costs and operation maintenance costs were
calculated and compared for each of the four
sub-alternatives. The capital costs of the sys-
tems were: System I, $18 million; System
II, $17 million; System III, $9 million; and
System IV, $8 million. On the basis of costs
and system reliability, it was concluded that
if a tertiary system were desirable, System III
would be considered the best of the four
alternatives.
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Land Application Assessment
Agricultural production dominates a sub-
stantial portion of the arable land, and with
only eleven inches of precipitation annually,
irrigation water from canals or deep wells
is a necessity. Because of the large volume of
treated wastewater flow and the high con-
centration of nutrients, land application was
not just viewed as a disposal alternative but
as a potential resource use for irrigation and
a source of supplemental nutrients as well.
To demonstrate the potential use of waste-
water to increase crop production, Simplot
funded an experiment conducted by the
University of Idaho on test agricultural plots.
Separate plots growing pasture grasses were
irrigated with normal irrigation water only,
irrigation water and commercial fertilizer, and
wastewater effluent from Simplot. To assess
the difference in yields from the latter two
plots, the nitrogen content of the commercial
fertilizer plot was made identical to that of
the wastewater plot. The experiment was
conducted for two growing seasons. Results
of the second season are still being assessed
but appear to support the conclusions drawn
from the first season. As can be seen in Table
2, the first season's crop yields from the ef-
fluent plot were higher than those of the
latter two.
Potential land application sites which
could be used as productive agricultural
areas were therefore sought. Several pre-
liminary locations were chosen for their
potential contributions to agricultural pro-
duction. Ownership of land parcels was also
a consideration. Although land costs would
be associated only with storage impound-
ments, land fully under City ownership would
reduce these potential costs. In addition,
areas with many tracts under individual
ownership were rejected and suitable areas
with few owners to negotiate with were pur-
sued. On the basis of these preliminary deci-
sion criteria, three alternative sites, depicted
in Figure 4, were selected for study:
Site I - Land at the Pocatello Airport
under City ownership with ap-
proximately 1,800 acres avail-
able for land application,
located one mile from the treat-
ment plant.
Site II - Land to the west of the Pocatello
Airport, 30% deeded and 70%
Indian tribal or under control of
the Fort Hall Reservation.
Approximately 6,000 acres avail-
able, located three miles from
the treatment plant.
Site III - Land (termed the East Bench)
located northeast of Pocatello
and under private ownership.
Approximately 7,000 acres avail-
able, located six miles from the
treatment plant.
The alternative land application sites were
evaluated for their potential success using the
following basic design criteria:
• No surface runoff of effluent should occur.
• Land in excess of 12% slope is not
acceptable.
• Crops should be harvested to remove the
maximum amount of nutrients from the
field.
• Groundwater migration should be con-
trolled as needed by wells.
• Ponding of effluent should not occur.
Table 2. - Comparison of average crop yields for test plots
Plot
Control
Commercial fertilizer
Simplot effluent
% crude protein
in grass
13
19.4
19.2
Tons/acre
removed 8-2-76
1.5
2.2
2.7
Tons/acre
removed 9-21 -76
1.9
3.3
4.3
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• On-site storage capacity should be pro-
vided to allow year-round use of the
industrial effluent (six months storage).
• All industrial flows should be used for
land application.
• Pocatello's wastewater plant effluent to
be fully used during the summer without
storage and initially with winter applica-
tion during favorable weather and
discharge to the river at other times.
Preliminary cost estimates were prepared
for a full capacity, year-round system includ-
ing pipelines, sprinkler irrigation systems, on-
site storage lagoons (resource recovery im-
poundments), site preparation, engineering,
and contingencies. Comparative costs were
approximately $4 million for Site I; $3 mil-
lion for Site II; and $6 million for Site III.
Political and coordination problems regarding
Sites I and II caused Site III to be considered
most feasible for approval and use.
SELECTION OF THE LAND APPLICATION
SITE
The possibility of using existing facilities
at the Pocatello wastewater treatment plant,
one of the three primary alternatives, was
abandoned early because water quality cri-
teria would not be met. In addition, as
shown in Table 3, a cost comparison between
the four physical-chemical systems and the
land application alternatives clearly indicates
that land application is the most cost-effective
solution.
Cost considerations for land application at
Site II were not analyzed in detail because of
the complications in dealing with the Tribal
Council of the Fort Hall Indian Reservation.
When the costs of Site I (Airport) were
compared with those of Site III (East Bench),
Site I was determined to be the most econom-
ically attractive alternative. There was, how-
ever, the legal question of whether Pocatello
or the Fort Hall Reservation actually owned
the land. Additionally, aviation authorities
were concerned that growing crops would
attract birds to the Airport from the nearby
American Falls Reservoir and create a safety
hazard.
After further evaluation, Site III was deter-
mined to be the best alternative despite its
higher cost, since the wastewater would be
used as an agriculturally productive resource.
Also costs could be partially recovered by
assessing a fee to those farmers who used the
wastewater. Prior to site selection, the
SICOG conducted several meetings with
farmers in the Site III area to discuss the
land treatment alternative. These meetings
indicated that area farmers were very inter-
ested in the project and that the demand for
wastewater irrigation was greater than the
supply. Of the 7,000 acres at Site III, about
half had no source of irrigation water and
"dry farming" has been practiced. In addi-
tion to opening this acreage to irrigation and
increased productivity, the land application
system provides nutrients (primarily nitrogen
and phosphorus in the treated effluent) that
represent a present annual value of approxi-
mately $250,000 in fertilizer to area farmers.
Table 3. — Cost comparisons of joint land treatment vs. joint physical-chemical treatment systems
Method
of treatment
Alternative 1
Alternative II
Alternative III
Alternative IV
Land Application
Site 1 - Airport
Site II - Fort Hall Reservation
Site III - East Bench
Total
capital cost
$
18,289,000
17,378,000
9,736,000
8,825,000
3,112,000
Not investigated
6,000,000
Annual
capital cost
$/year
1,546,000
1,469,000
823,000
746,000
263,000
507,000
O & M cost
$/year
1,315,000
1,094,000
979,000
758,000
100,000
100,000
Total
annual cost
$/year
2,861,000
2,563,000
1,802,000
1,504,000
363,000
607,000
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Site III is also large enough to permit a
phased approach, thus reducing the initial
front-end cost from $6 million to $3 million.
The $3 million investment in the first phase
will permit summer irrigation with discharges
from Simplot as well as the City of Pocatello.
In the winter, Simplot's effluent alone would
be stored in the resource recovery impound-
ment and Pocatello would discharge to the
Portneuf River in accordance with its NPDES
permit requirements. The second phase would
provide for year-round storage and irrigation
of both the City and Simplot's discharges and
would result in zero discharge to the Portneuf
River. The selected alternative and the East
Bench application site are shown in Figure 5.
The use of joint effluent flows for irrigating
and fertilizing farm land has been largely sup-
ported by the farmers in the Site III area.
These area farmers who purchase irrigation
water from the Fort Hall Canal pay about $13
per acre per year for canal water and the cost
has been increasing. The water table in the
East Bench area has dropped significantly in
the last few years, thus increasing pumping
costs for farmers who utilize their own deep
wells. In addition, nitrogen fertilizer costs
approximately $50 per acre per year and
prices are rising. These factors, not to men-
tion recurring drought, have stimulated
farmers' interest in an alternative to dry land
farming and a new source of nutrients. The
public has therefore largely supported the
implementation of the project.
Consideration was given to the potential
effects on groundwater from the land appli-
cation system. Groundwater problems were
determined to be minimal due to the water
table in the area being, on the average, 100
feet deep and irrigation water would not
penetrate much deeper than the root zone.
Also, there are very few potable wells in use
in the East Bench area. Little or no odor and
contamination are expected from spray irri-
gation because the wind direction will carry
any aerosols into uninhabited mountain
areas 90 percent of the time.
STEPS TOWARD IMPLEMENTATION
A high degree of coordination has been
maintained through the Joint Waste Treat-
ment Feasibility Study. The SICOG, through
the 208 Planning process, provided the
needed impetus to innovate a cost-effective
disposal method for municipal and industrial
wastewater. Since the completion of the
Study, considerable effort has been directed
toward implementation.
The construction contract has been exe-
cuted and acceptance of the operation and
maintenance contract is expected in early
1978. Once the latter contract is executed,
the procedures, costs, and necessary agree-
ments which will govern the tap-on policy
and user fee for area farmers who desire to
utilize the wastewater for irrigation can be
drafted.
The entire project will be implemented
using local funds and without the use of fed-
eral or state grant assistance. Financing will
be accomplished initially by Pocatello con-
tributing the $100,000 that was set aside
earlier for additional wastewater treatment
and J.R. Simplot paying the remainder of
system costs. The City would then repay
Simplot from user fee revenues for the full
cost of their portion of the system. That cost
will be determined by advertising for separate
bids for a pipeline from the Pocatello WWTP
to the impoundment to serve Simplot's 1985
projected flow of 3 mgd and one for the
City's 1985 projected flow of 12 mgd. The
difference in these costs will represent Poca-
tello's share of the pipeline cost. The J.R.
Simplot Company views this as a cost-effec-
tive approach for meeting its permit require-
ments.
As conceived, the City will be responsible
for system operation and maintenance, with
costs shared proportional to each party's
volume of flow. Revenues from sale of irri-
gation water will be used to pay operation
and maintenance costs. Revenues in excess
of operation and maintenance costs will be
distributed two-thirds to the City and one-
third to Simplot.
Revenues from the sale of irrigation water
will be based on 70 percent of the current
market cost of nutrients to the land. This
rate will remain constant over the next 5
years.
Since groundwater constitutes the primary
potential impact of the land application sys-
tem, monitoring wells will be established
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around the resource recovery impoundment.
Approval by the Idaho Department of En-
vironmental and Community Services is
needed based on design and operational con-
siderations, including acceptable monitoring
safeguards. Additionally, Idaho State Uni-
versity will study the disposition of sludge at
the site while the Department of Agriculture
will perform research on the nutrient uptake
by crops.
As the result of SICOG's areawide water
quality planning efforts and the expertise
and leadership of the City of Pocatello and
J.R. Simplot, an innovative approach toward
water quality improvement is being imple-
mented. Once approved, the land application
system will initially result in the elimination
of Simplot's discharge to the Portneuf River,
and utilize the summer flow from the Poca-
tello wastewater treatment plant. Utilization
of wastewater effluent as a productive re-
source will result in generation of revenues
from user fees, increased crop yields and an
increase in productive acreage in the East
Bench area. This creative interplay of tech-
nical and planning skills was brought together
through the efforts of SICOG and made pos-
sible by use of a 208 planning grant.
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•d U S GOVERNMENT PRINTING OFFICE 1978— 757-140/6682
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