HomeMy WebLinkAboutJUB Engineers Inc - Industrial Reuse Facility 2010 Capacity AnalysisINDUSTRIAL REUSE FACILITY
2010 CAPACITY ANALYSIS
CITY OF PASCO
PASCO, WA
DECEMBER 2010
M
Submitted by:
J -U-13 Engineers, Inc
2810 W. Clearwater Ave., Ste 201
Kennewick, WA 99336
509-783-2144
Table of Contents
ExecutiveSummary ..................................................................................................
ES -1
Section 1. Existing Conditions......................................................................................
1
1.1. Existing Facility Details......................................................................................
1
1.2. Existing Flows and Loads..................................................................................1
8
1.3. Existing Permit Summary ...................................................................................
2
Section 2. Existing Capacity Analysis...........................................................................
3
2.1. Hydraulic Capacity.............................................................................................3
8
2.2. Total Nitrogen Capacity......................................................................................
3
2.3. BOD Capacity....................................................................................................
3
2.4. Storage Capacity................................................................................................3
10
2.5. Summary of Existing Capacity Limitations.........................................................
4
2.5.1. Permit Parameters.......................................................................................4
2.5.2. Physical Facilities........................................................................................
5
2.5.3. Crop Selection.............................................................................................5
Section 3. Future Flows and Loads Projections...........................................................
7
Section 4. Future Capacity Analysis.............................................................................
8
4.1. Hydraulic Capacity.............................................................................................8
Alternative #2:
4.2. BOD Capacity....................................................................................................
8
4.3. Total Nitrogen Capacity......................................................................................
8
4.4. Storage Capacity................................................................................................
8
4.5. Summary of Capacity Impacts from Additional Flows and Loads .......................
8
Section 5. Alternatives to Accommodate Additional Flows and Loads .......................
10
5.1. Identification of Alternatives.............................................................................
10
5.2. Evaluation of Alternatives.................................................................................
10
5.2.1.
Alternative #1:
Purchase Capacity from One of the Other Contributors ....10
5.2.2.
Alternative #2:
Increase the Capacity of the Existing Reuse Facility .........11
5.2.3.
Alternative #3:
Purchase Part of the City's Reserve Capacity ...................
11
5.2.4.
Alternative #4:
Create a New Reuse Facility and Divert Flow to the New
facility..................................................................................................................12
5.2.5.
Alternative #5:
In -Plant Flow and Load Reductions...................................12
Section 6.
Recommendations.....................................................................................13
J -U -B ENGINEERS, Inc.
6.1.
Optimize the Land Application Area.................................................................13
6.2.
Address Farmers Concerns.............................................................................13
6.3.
Address Grit Accumulation...............................................................................14
6.4.
Allow Increased Flows.....................................................................................15
6.5.
Evaluate Other Alternatives.............................................................................15
J -U -B ENGINEERS, Inc. ,, ,F.
CITY OF PASCO, WASHINGTON
Industrial Reuse Facility
2010 Capacity Analysis
Executive Summary
The primary goal of this feasibility study for Pasco's Industrial Reuse Facility (IRF) is to
evaluate the existing IRF based on 2009 flows and loads to: estimate remaining
capacity, determine impacts of additional flow, and identify potentially feasible
alternatives to best accommodate the process water projected to be discharged to the
facility from its contributors in the immediate future.
In 2009, the IRF:
• Applied 62 percent of its rated hydraulic capacity
• Applied 61.6 percent of its rated total nitrogen capacity
• Applied 41 percent of its rated BOD capacity
• Stored 74 percent of its rated storage capacity
Assuming the influent wastewater characteristics remain about the same, hydraulic
considerations' limit the overall capacity of the IRF. The permitted hydraulic capacity of
the IRF is 1003.4 million gallons (MG) per year (which would allow for an additional 380
MG that could be received and land applied over the amount applied in 2009).
Should the IRF receive an additional 41.6 MG from a contributor wishing to increase
production, the IRF can accommodate this flow by:
• Increase a contributor's allocation to the IRF by purchasing or renting capacity
from another contributor(s) that is not currently utilizing their entire allocation and
reducing the amount of capacity held in reserve.
• Increase the capacity of the IRF and allocate the increased capacity to the
contributor in need of capacity. Capacity at the IRF could be increased by adding
land application acreage with concurrent implementation of additional treatment
measures at the plant site to address aesthetic issues that limit farmers'
willingness to accept the process water such as odors, excess nitrogen impacts
on alfalfa quality, and nozzle plugging by solids.
• Increase the expanding contributor's allocation out of the City's existing 100 MG
per year reserve capacity at the IRF. The increased allocation should be
purchased by the contributor at a sufficient price to enable the City to restore the
Storage is the primary limiting factor; land area is the next limiting factor depending on when the flow is
received.
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reserve capacity in a timely manner to accommodate future changes in
conditions, changes in permit requirements, and expansions at other contributor
facilities.
• Construct a new reuse facility at a new location and divert a portion of the flow
from the IRF to this new facility freeing up capacity at the IRF which can be
allocated to the contributor in need of capacity.
• Implement in-house flow and load reduction measures at the expanding
contributor's facility.
The above alternatives may be combined to address the project goals and each have
pros and cons with specific issues to be addressed that are discussed in detail in the
following report.
The following tasks and action -items are recommended:
1. Develop a land management plan that will fully utilize and maximize the effluent
disposal capacity of the spray fields. Ascertain the functionality of the existing
1,800 acres of irrigation area to determine if capacity de -rating is necessary due
to the inability to irrigate 20.53 inches to all 1,800 acres prior to reaching the
permitted limits of the IRF.
2. Fully investigate the nozzle plugging issue to determine if debris enters the IRF in
the influent and/or is wind driven into the lagoons. Dealing with the nozzle
plugging issue will restore lost capacity due to inefficient irrigation and promote
confidence in the reuse product so that other farmers may choose to use the
reuse water.
Build an automated influent screening and grit removal facility to reduce labor
cost and increase functionality and reliability. This item will be especially critical
if the nozzle plugging issue is related to debris in the influent. If the debris is
related to wind -driven tumble -weeds, a debris fence or effluent screen will be
required.
4. Decide upon an equitable way to allow additional flow to enter the IRF from a
new or existing user. It is recommended that the City allow additional flow by
sacrificing some of the 100 MG reserve capacity with the understanding that the
reserve capacity must be restored when the IRF approaches capacity or when
conditions or permit requirements change. This concept will work as long as the
spray fields can be reasonably optimized and the flow currently (allocated but not
fully utilized) from the other dischargers does not increase too rapidly.
J -U -B ENGINEERS, Inc.
Industrial Reuse Facility
2010 Capacity Analysis
Section 1. Existing Conditions
1.1. Existing Facility Details
Details regarding the existing facility can be found in the original Engineering
Report for the facility as well as the 2008 Operations and Maintenance Manual
and are incorporated herein by reference. The existing facilities consist mainly of
the following components:
• A collection system pumping station and force main (5.5 mgd capacity)
• One 5 MG aerated equalization lagoon
• One 115 MG aerated storage lagoon
• An irrigation pump station (3,400 gpm capacity)
• Distribution piping which conveys process water to 14 center -pivot irrigation
circles
• 11 wells that provide supplemental irrigation
• A manually cleaned influent screen
1.2. Existing Flows and Loads
The 2009 daily monitoring reports (DMRs) were used to estimate the existing
flows and loads entering the IRF. The monthly influent flow entering the IRF as
well as the irrigation flow, total nitrogen (TN) load and biochemical oxygen
demand (BOD) load are reported in Table 1.
Table 1. 2009 Influent and Irrigation Flows and Loads
Max day
Daily Ave
Max day
Daily Ave
Total BOD
Influent
Influent
Irrigation
Irrigated
TN Irrigated
Irrigated
MGD
MGD
MGD
MGD
Ib/month
Ib/month
January
0.965
0.5
February
1.25
0.795
March
1.038
0.69
4.45
2.733
43,146
1,104,955
April
1.069
0.558
3.88
0.994
13,777
217,776
May
1.275
0.679
2.74
1.052
14,060
183,866
June
2.93
2.15
3.51
2.264
53,844
635,000
July
3.48
2.068
3.35
2.123
80,724
1,759,400
August
4.586
3.855
4.7
3.821
140,390
5,245,929
September
4.552
4.078
4.69
4.102
105,670
5,463,788
October
4.698
2.687
4.63
2.656
67,260
4,263,398
November
1.619
1.362
2.05
1.358
14,491
482,435
December
1.46
0.985
Yearly
Total
622.7 MG
622.2 MG
533,362 Ib
19,356,547 Ib
MG = million gallons
MGD = million gallons per day
Ih = nn,,ndi
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- Industrial Reuse Facility
2010 Capacity Analysis
The annual average TN and BOD concentrations during 2009 were 103 and
3730 mg/I, respectively.
1.3. Existing Permit Summary
The IRF operates under the State Waste Discharge Permit Number ST 5369
administered by the Washington Department of Ecology (WDOE) which is
incorporated herein by reference. The parameters specifying the loading limits
were used to evaluate the treatment facility. Key operating parameters and their
permit limits are:
1. Maximum Flow (averaged over one month) = 10.6 MGD
2. Maximum Annual Flow = 1,003.4 MG
3. Maximum Daily BOD load = 355,600 pounds of BOD
4. Maximum Annual TN Load = 866,246 pounds of TN
5. Irrigation Area = 1,800 acres.
Based on the above limits, the permit allows:
1. 20.53 inches of reuse water to be applied annually for irrigation (actual
irrigation demand to satisfy crop requirements is estimated to be 38.5
inches2).
2. 481 pounds of TN per acre per year.
3. 355,600 pounds of BOD per day
The likely intent of limiting reuse water to 20.53 inches per year is to force
additional irrigation with "clean" water to meet the leaching requirements that
keep total dissolved solids (TDS) from building up in the soil.
2 WA210-VI-WAIG, OCTOBER 1985
J -U -B ENGINEERS, Inc.
Industrial Reuse Facility
2010 Capacity Analysis
Section 2. Existing Capacity Analysis
The hydraulic capacity, BOD loading capacity, TN loading capacity, and storage
capacity based on the 2009 flows and loads are discussed below.
2.1. Hydraulic Capacity
In 2009, the treatment facility applied 622.7 MG. The facility is permitted for
1,003.4 MG; therefore, the facility could receive 61.3 percent more flow (381.2
MG) and is currently not hydraulically limited.
2.2. Total Nitrogen Capacity
In 2009, the treatment facility applied 533,362 pounds of TN. The facility is
permitted for 866,246 pounds of TN; therefore, the facility could receive 62.4
percent more TN (332,884 pounds) assuming the TN concentration in the
effluent remained the same. If the TN concentration in the effluent remains about
the same, the hydraulic capacity would continue to control the overall capacity;
however, if the TN concentration in the effluent increases substantially, TN would
become the limiting parameter and the amount of water applied would need to be
reduced.
2.3. BOD Capacity
In 2009, the highest application rate was 4.69 MGD. Using the annual average
BOD concentration of 3,730 mg/I, the daily load would be 145,909 pounds per
day. The permitted BOD application rate is 355,600 pounds per day; therefore,
assumptions remain valid, the facility can treat 144 percent more BOD (209,691
pounds). However, this permitted BOD load could be applied in a number of
different ways. For example:
• Given the maximum daily flow of 10.6 MGD and the maximum daily BOD
application of 355,600 pounds allowed by the permit, the maximum effluent
BOD concentration at the maximum flow could be 4,022 mg/I; or
• In 2009, the highest application rate was 4.69 MGD. If the highest application
rate remained the same, the effluent BOD concentration could increase to
9,091 mg/I before the permit BOD limit was exceeded; or
• Given the maximum daily load of 355,600 pounds allowed by the permit and
the annual average BOD concentration of 3,730 mg/l, the maximum flow
could be 11.4 MGD which is higher than the amount allowed in the permit
(10.6 MGD).
2.4. Storage Capacity
Based on the average daily flow received during the non -application months in
2009 (December, January, and February), the storage lagoon had to contain
69.2 MG. The storage lagoon volume has a 115 MG capacity; therefore, the
lagoon had excess capacity in 2009.
J -U -B ENGINEERS, Inc.
Industrial Reuse Facility
2010 Capacity Analvsis
Assuming similar month-to-month flow ratios, when the annual flow reaches the
permitted capacity of 1,003.4 MG, the storage lagoon will have to contain 112
MG which is still less than the 115 MG capacity of the existing storage lagoon.
Therefore, the storage lagoon does not limit the capacity. However, the monthly
flow ratio assumption is critical as a slight change in the timing of the influent flow
would cause the storage lagoon capacity to be exceeded. Monthly flows for an
annual flow of 1,003.4 MG based on 2009 flow ratios are reported in Table 2.
Table 2. Expected Average Monthly Flows Based on 2009 Ratios
2.5. Summary of Existing Capacity Limitations
To summarize, the capacity can be limited by any of the three main permit
parameters or by the physical IRF infrastructure, or by crop selection at the land
application area.
2.5.1. Permit Parameters
Assuming the reuse water characteristics remain about the same (3730 mg/I
BOD and 102.8 mg/I TN), the permitted hydraulic application rate limits the
overall capacity of the IRF (maximum daily flow < 10.6 MGD and annual flow <
1003.4 MG). BOD and TN do not limit the facility.
However, if groundwater quality expectations required in the permit are not met,
any constituent violating the expectation could trigger a stringent discharge
limit. At this time, no groundwater parameter is an immediate concern;
however, TDS and TN in the groundwater should continue to be closely
monitored.
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2009 Daily
Ave Influent
MGD
Maximum Daily
Ave Influent
MGD
January
0.5
0.81
February
0.795
1.28
March
0.69
1.11
April
0.558
0.90
May
0.679
1.097
June
2.15
3.47
July
2.068
3.34
August
3.855
6.229
September
4.078
6.59
October
2.687
4.34
November
1.362
2.2
December
0.985
1.59
Yearly Total
622.7 MG
1003 MG
MG = million gallons
MGD = million gallons per day
2.5. Summary of Existing Capacity Limitations
To summarize, the capacity can be limited by any of the three main permit
parameters or by the physical IRF infrastructure, or by crop selection at the land
application area.
2.5.1. Permit Parameters
Assuming the reuse water characteristics remain about the same (3730 mg/I
BOD and 102.8 mg/I TN), the permitted hydraulic application rate limits the
overall capacity of the IRF (maximum daily flow < 10.6 MGD and annual flow <
1003.4 MG). BOD and TN do not limit the facility.
However, if groundwater quality expectations required in the permit are not met,
any constituent violating the expectation could trigger a stringent discharge
limit. At this time, no groundwater parameter is an immediate concern;
however, TDS and TN in the groundwater should continue to be closely
monitored.
J -U -B ENGINEERS, Inc.
Industrial Reuse Facility
2010 Capacity Analysis
2.5.2. Physical Facilities
When the annual average flow reaches the permitted capacity, the required
storage is very close to the maximum available storage assuming monthly flow
ratios remain about the same. It is likely that the monthly flow ratios assumed
during this analysis will change as the flows increase; therefore, available
storage may become critical and limit the IRF. Flow during the non -discharge
season should be closely monitored and the dischargers should let the City
know several years in advance if their non -discharge season flows will
increase.
The system currently has an irrigation nozzle plugging problem3 Plugging of
nozzles not only requires additional maintenance but affects the uniformity of
application and crop yield. The nozzle plugging impacts on crops have caused
a negative perception of industrial water reuse and are a main reason why
neighboring farmers are hesitant to contract with the facility to accept and apply
process water on their farms.
Therefore, influent screening at the IRF is recommended to minimize the
plugging of irrigation nozzles which will help to maximize use of the existing
sprayfield and improve the overall perception of industrial water reuse.
Screening could also have the increased benefit of reducing the nitrogen and
BOD applied to the sprayfields by screening out a portion of the solids normally
applied. The IRF currently has a manually cleaned influent screen which is
insufficient to protect the nozzles. It is recommended that this screen be
replaced with an automated screen with a finer mesh to remove the nozzle
plugging material.
Additionally, grit accumulates in the IRF lagoons which reduces functionality
and capacity and has to be removed manually. Manually removing the grit
requires that the lagoons be off-line which reduces availability. Therefore, an
automated influent grit removal facility is recommended.
To further protect the nozzles, a fence should be constructed around the
lagoons to catch wind driven debris (e.g. tumbleweeds) that has a history of
plugging nozzles. If wind -driven debris continues to plug nozzles, an effluent
filter should be considered.
2.5.3. Crop Selection
The types of crops planted on the sprayfield are currently not optimal for land
application performance. For example, potatoes cannot receive irrigation water
for a long period prior to harvest. The City should regularly review crops
' Based on discussions with the operations staff
J -U -B ENGINEERS, Inc.
Industrial Reuse Facility
2010 Capacity Analysis
selected and ensure that they maximize the ability to dispose of process water.
The highest priority for crop selection should be to maximize process water
disposal when the facility is nearing capacity.
Note: Analysis of other physical infrastructure (pumps, transfer structures, and
other conveyance systems) was not part of this study.
J -U -B ENGINEERS, Inc.
Industrial Reuse Facility
2010 Capacity Analysis
Section 3. Future Flows and Loads Projections
There are four entities that contribute flow to the IRF. As part of this study, an analysis
was completed to consider the impacts of one of these contributors increasing flow by
an additional 41.6 MG per year (7% overall increase) which would result in a total
annual flow of 664.3 MG. It was assumed that the expanding contributor would
contribute additional flow as summarized in Table 3.
Table 3. Estimated Monthly Flows for an Annual Flow of 664.3 MG
2009 Daily + 41.6 MG
Ave Influent Daily Ave
Month MGD Influent MGD
January
0.5
0.50
February
0.8
0.80
March
0.69
0.69
April
0.56
0.56
May
0.68
0.74
June
2.15
2.35
July
2.068
2.26
August
3.855
4.21
September
4.078
4.46
October
2.687
2.94
November
1.36
1.36
December
0.99
0.99
Yearly Total 622.7 MG 664.3
MG = million gallons
MGD = million gallons per day
Months of Increased
Flow (41.6 MG total)
Additionally the total flow, BODS and nitrogen expected from the expanding contributor
are summarized in Table 4. Note that Table 4 assumes that the expanding contributor
has an existing allocation of 200 MG.
Table 4. Expected Additional Flows and Loads
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Expected Flow
(MG)
BOD (Ib/d)
Total Nitrogen (lb)
January
February
March
April
May
4.98
24,915
4,152
June
27.38
22,839
22,839
July
34.65
51,138
34,646
August
60.29
129,754
70,392
September
60.29
134,079
70,392
October
54.00
87,294
48,376
November
December
Total =
241.59
250,796
J -U -B ENGINEERS, Inc.
Industrial Reuse Facility
2010 Capacity Analvsis
Section 4. Future Capacity Analysis
The hydraulic capacity, BOD loading capacity, TN loading capacity, and storage
capacity based on future increases in flows and loads are discussed below.
4.1. Hydraulic Capacity
The additional 41.6 MG would bring the overall expected annual flow to 664.3
MG (622.7+41.6). If the combined waste characteristics remain the same and
the hydraulic capacity continues to be the limiting parameter, the existing IRF
could receive and dispose of all the additional flow and still only be at 66% of
hydraulic capacity (664.3/1003.4).
4.2. BOD Capacity
Assuming the 41.6 MG arrives at the IRF over a 60 day period and that the BOD
concentration is similar to the maximum month concentration (140 mg/), the extra
flow would add an additional 780 pounds of BOD per day to the IRF. In 2009,
the average daily load to the irrigation field was estimated to be 145,909 pounds
per day. Since the maximum application rate is 355,600 pounds per day, the
addition of 780 pounds per day would not limit the facility.
4.3. Total Nitrogen Capacity
Assuming the additional 41.6 MG has a TN concentration similar to the annual
average (124 mg/1), the extra flow would add an additional 41,366 pounds of total
nitrogen per year. In 2009, the treatment facility applied 533,362 pounds of TN.
Since the facility has the ability to apply 866,246 pounds of TN per year, the
additional 41,366 pounds per.year would not limit the facility.
4.4. Storage Capacity
Assuming that the additional flow would not occur during the non -application
season (winter months), there are no impacts on storage requirements. Monthly
flow estimates for an annual flow of 664.3 MG are reported in Table 3.
If flows do increase during the winter months, further analysis should be done on
the water balance to determine if additional storage is needed.
4.5. Summary of Capacity Impacts from Additional Flows and Loads
The existing facilities can accommodate the additional flow of 41.6 MG per year
expansion. However, each of the four current users originally "bought in" to the
reuse facility, and each were allocated a flow and load based on their "buy -in"
ratios. The allocated flows and loads to each of the current users are
summarized in Table 5.
J -U -B ENGINEERS, Inc.
Industrial Reuse Facility
2010 Capacity Analysis
Table 5. IRF Permitted and Allocated Flows and Loads
IRF Pasco Twin City Reser's Bybee Reserve
(permitted) Processing Foods Foods Capacity
Avg flow 10.60 MGD',' 2.5 MGD 1,5 2.4 MGD' 0.3 MGD' 4
1.25 MGD' 4.15 MGD
(max. month)
Total annual 1,003.4 MG 1" 383.41 MG200 MG115 MG 1,4
205 MG 100 MG
flow
BODS load 355,600 ppdl" 127,000 ppd2 124,974 ppd 8 7,200 ppd'' 4
29,6001 ppd 66,826 ppd
(max. month)
TN load 866,246 lbs 1,8 270,000 lbs "' 179,600 lbs' 72,000 lbs 1.4 184,000' lbs 160,646 lbs
' Permit limitation
2 Value given in permit modification application received August 7, 2009.
a Twin City Foods city allocation; eng. rpt. addendum, April 2007.
4 Design value: Reser's updated engineering evaluation update; 2007.
5 Values given in permit modification application received June 10, 1997.
6 Value agreed to by Simplot in letter dated February 28, 1999.
7 Revised capacity values in Rev No. 2 to Suppl. No. 2 of eng. rpt. (July 2005)
8 Based on updated crop rotation for the period 2009-2015.
As an example, if Twin City Foods increased their discharge by 41.6 MG, it would
exceed their "buy -in" ratios by:
• Annual flow (20% over)
• Allowable monthly BOD5 load (4% over in August and 7% over in September)
• Allowable annual nitrogen load (29% over)
Therefore, there are some administrative tasks to consider for accommodating future
flows and loads. Moreover, the City should maintain a buffer between permitted
capacity and operating capacity. The following section examines various alternatives to
accommodate the projected increases in flows and loads
J -U -B ENGINEERS, Inc.
Industrial Reuse Facility
2010 Capacity Analysis
Section 5. Alternatives to Accommodate Additional Flows and Loads
A number of alternatives to accommodate the increased flows and loads were
investigated:
5.1. Identification of Alternatives
1. Increase a contributor's allocation to the IRF by purchasing or renting
capacity from another contributor(s) that is not currently utilizing their entire
allocation and reducing the amount of capacity held in reserve.
2. Increase the capacity of the IRF and allocate the increased capacity to the
contributor in need of capacity. Capacity at the IRF could be increased by
adding land application acreage with concurrent implementation of additional
treatment measures at the plant site to address aesthetic issues that limit
farmers' willingness to accept the process water such as odors, excess
nitrogen impacts on alfalfa quality, and nozzle plugging by solids.
3. Increase the expanding contributor's allocation out of the City's existing 100
MG per year reserve capacity at the IRF. The increased allocation should be
purchased by the contributor at a sufficient price to enable the City to restore
the reserve capacity in a timely manner to accommodate future changes in
conditions, changes in permit requirements, and expansions at other
contributor facilities.
4. Construct a new reuse facility at a new location and divert a portion of the
flow from the IRF to this new facility freeing up capacity at the IRF which can
be allocated to the contributor in need of capacity.
5. Implement in-house flow and load reduction measures at the expanding
contributor's facility.
It is important to note that hydraulic capacity limits the facility; therefore, nitrogen
and BOD removal as part of a treatment alternative would not increase capacity
as the system is hydraulically limited.
5.2. Evaluation of Alternatives
The alternatives identified above are discussed in further detail below. It should
be noted that with all of the identified alternatives, the addition of influent
screening and grit removal facilities at the IRF is recommended.
5.2.1. Alternative #1: Purchase Capacity from One of the Other Contributors
This alternative may have to be approved by WDOE.
The delivery system may have to be upsized:
a. Can the contributor pump the increased flow to the facility?
b. Does the conveyance system have the hydraulic capacity?
J -U -B ENGINEERS, Inc.
Industrial Reuse Facility
2010 Capacity Analysis
3. Will the other entities still be able to pump into the common line without
exceeding its hydraulic capacity?
4. The cost to purchase from another entity should be market-driven unless
WDOE rules limit it to real cost to serve.
5. As long as the total combined allocation of all contributors stays the same,
the impacts to the City's ability to stay in compliance should not be
impacted.
5.2.2. Alternative #2: Increase the Capacity of the Existing Reuse Facility
An additional 360 acres under irrigation, assuming a similar permit can be
obtained. Some of the issues that would have to be addressed are:
1. Additional land application site would be needed.
a. Suitable land has to be found and purchased:
i. No ground water concerns
ii. Under an existing agriculture management plan
iii. Adequate water rights for flush water and/or supplemental
irrigation
b. Irrigation system
C. Monitoring program
d. Farm report
e. WDOE land application permit
f. Farmer concerns (e.g. nozzle plugging)
g. Excess TN impacts on aquifer considered
h. Public acceptability (e.g. odors)
2. Delivery system:
a. Will they be able to share any part of the existing system?
b. New pump station
C. New force main
3. Additional storage may be needed depending on when the flow is
generated. However, the existing facility only stores about 70 MG so
there is excess capacity. The issue of storage allocation among the
contributors may need to be addressed.
5.2.3. Alternative #3: Purchase Part of the City's Reserve Capacity.
The 100 MG per year reserve capacity protects the City from unexpected
events; however, the reserve capacity could be used to allow an additional
food processer to locate in the area or the expansion of an existing user if
sufficient buffer remained and/or the buffer was restored in a timely manner.
This concept would allow additional flow immediately rather than waiting the
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Industrial Reuse Facility
2010 Capacity Analysis
years it would take to add capacity first. The required improvements for
additional capacity additions would be similar to Alternative 2
5.2.4. Alternative #4: Create a New Reuse Facility and Divert Flow to the New
facility
1. A new land application area of at least 360 acres under irrigation would be
needed depending assuming a similar permit can be obtained (might have
to buy more to get the amount needed under irrigation).
2. Delivery system
3. Irrigation system
4. Wide spot for winter storage
5. New storage requirements could be reduced by storing the winter flow at
the existing IRF (if the contributor has a storage allocation).
5.2.5. Alternative #5: In -Plant Flow and Load Reductions
Implementation of this alternative would be by the contributor.
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Section 6. Recommendations
6.1. Optimize the Land Application Area
The IRF land application permit allows more flow than the 622.2 MG applied in
2009 and, in theory, the IRF is capable of receiving more flow if land
management practices do not limit.
Therefore, land management practices should be reviewed and a plan created to
optimize land capacity. The plan could be to operate the facility as convenient
while a significant amount of excess capacity remains; however, as flows
increase, the land management plan and practices may have to be modified to
optimize the effluent disposal capacity of the land.
As the IRF approaches capacity, the land and crops will have to be managed to
optimize production to ensure 20.53 inches of water can be applied on 1,800
acres. If not, the overall capacity of the IRF will need to be reduced. A task
should be completed to inventory the existing viable crop acreage and determine
the suitability of the crop for the primary function of process water disposal.
Recommendations on the best crops for the primary use should be solicited from
experts, and the City should coordinate with the farmers to ensure that only those
crops are planted when maximum capacity is needed. Part of the optimization
task should also be to ensure the irrigation equipment performs adequately.
Additional flows will push the facility closer to its design limits, and crop
optimization will be necessary to allow maximum flexibility in the operation and
maintenance of the facility.
6.2. Address Farmers Concerns
The IRF facility will become hydraulically limited (first storage and then land) as
flows increase. Therefore, constructing treatment capacity at the IRF will not
increase system performance or the ability to dispose of water. An increase in
system capacity will require either an increase in storage or land application
acreage depending on when flow is received. There is adequate space at the
facility to construct another storage lagoon with a volume of approximately 20
MG. There is additional farm land near the site that could be purchased;
however, getting nearby farmers to accept the reuse water would be more
economical. Many acres of farm land surround the IRF and it is likely that
constructing improvements which will minimize odors and irrigation nozzle
plugging will make the process water more attractive to neighboring farmers.
An influent screening and grit removal system should make the process water
more attractive to neighboring farms that are considering accepting the process
water on their land. The screening and grit removal step should alleviate the
sprinkler plugging problems and should allow a more uniform application of the
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process water increasing crop production. The screening step should also
reduce maintenance efforts that are currently spent cleaning sprinklers and
should extend the life of pumps and piping that are currently being excessively
worn by the grit in the process water. An additional benefit of the screening step
should be the reduction in the BOD and nitrogen being applied to the field. The
actual decrease in BOD and nitrogen load is difficult to estimate; however, a pilot
study could be conducted to quantify the reduction that could be realized through
the screening process. Implementing the screening and grit removal
improvements now should allow time for neighboring farmers to witness the
improvements so that when there is a need to increase acreage in the future, the
farmers should be more apt to negotiate.
As a first step, the nozzle plugging issue should be investigated more closely. If
the plugged nozzles are significantly decreasing the system capacity, at some
point that capacity will have to be recovered either by adding additional land or
addressing the plugging issue. If the nozzles are being plugged by material
entering the IRF from the food processors, an automated influent screen (fine
mesh) should address the issue. If the nozzles are being plugged by debris that
blows into the lagoons (tumbleweeds), an effluent filter may be required or a
debris fence around the IRF. The issue may also be addressed by increasing
maintenance activity on the irrigation system.
Once the nozzle plugging issue is better understood, the City should commission
a study to further explore screening and grit removal technologies. The study
would evaluate the various technologies available and provide preliminary
engineering and cost estimates for such a facility. Additionally, pilot testing
should be conducted to verify the technology chosen and quantify the benefits.
For planning purposes, an order -of -magnitude engineer's opinion of probable
cost to install influent grit removal and fine screen facilities is $1,500,000.
6.3. Address Grit Accumulation
The process water received at the IRF does contain grit that has caused some
operational problems. For example, grit has been accumulating in the 5 MG
lagoon which reduces the effective volume for treatment and storage. Moreover,
the grit causes excessive wear and tear on the pumps. Currently, the pumps are
re -built every other year because of the excessive abrasion. If it is a decided to
add an influent screen to the IRF, it is recommended to construct a combination
screening and grit removal system to remove grit as well. This will provide better
treatment and reduce accumulation in the 5 MG lagoon and will also reduce the
wear and tear on pumps and piping. As mentioned above, a fine screen and grit
removal system would cost approximately $1,500,000 to construct.
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6.4. Allow Increased Flows
In 2009, the City's IRF could have applied an additional 381.2 MG before being
limited by the permit and an additional 281.2 MG before using up the 100 MG
reserve capacity. Because there is excess capacity, the City should allow a new
or existing user to discharge flow to the IRF up to the 100 MG per year reserve
capacity and then build the reserve capacity back up to a comfortable level (see
Alternative 3 above). Note that there is a significant amount of capacity that has
been allocated but is not being used in addition to the 100 MG per year buffer.
Because there is so much capacity that is not being utilized, the City should allow
additional flow and then build the reserve capacity back. As long as the flow
from the existing dischargers remains near 67 percent of their allocated flow, a
significant buffer would still remain. The new or expanding contributor would
have to realize that they have less seniority to access the IRF and could
suddenly lose capacity if other dischargers suddenly increased flow and
additional capacity was not in place. It should be noted that an allocation could
also be obtained by purchasing capacity from an existing contributor with an
allocation rather than increasing capacity of the IRF.
The allocation of the reserve capacity amongst the four users or any future users
is an administrative task that City must consider in conjunction with WDOE as
WDOE may have regulatory reasons to hold a certain percent of the capacity in
reserve to guard against unforeseen circumstances.
6.5. Evaluate Other Alternatives
Further analysis of other alternatives such as a new reuse facility or new land
application area is likely not warranted until the above mentioned options are
exhausted.
° Assuming optimized land application rates
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