HomeMy Public PortalAbout2006.12.14 CH2M Hill - Draft Memo Eval of Wastewater Management Alternatives t
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DRAFT TECHNICAL MEMORANDUM CH2MHILL
IEvaluation of Wastewater Management Alternatives
ITO: City of McCall
FROM: Rick Bishop,P.E.,CH2M HILL
IDATE: December 14,2006
I Summary
This Technical Memorandum evaluates the wastewater management alternatives for the
1 City of McCall(City),and also provides information that is part of the development of a
wastewater facilities plan for the City.The purpose of this memorandum is to compare five
potential alternatives that utilize existing and new facilities.The alternatives are assembled
Ito satisfy long-term capacity needs in conformance with water quality requirements.
Wastewater Management Alternatives
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A wastewater management alternative includes all the components of a wastewater system.
Each wastewater management alternative may comprise treatment,storage,and effluent
I disposal to provide a complete solution.The goal of this part of the wastewater facilities
plan is to review the five wastewater management alternatives and select a preferred
alternative.An implementation plan for the preferred alternative will be developed during
Ithe next phase of the planning process.
The five wastewater management alternativesprovide a varietyof solutions.Total project
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costs for the alternatives range broadly from$58.5 million to$132 million,and combine
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elements of the existing facilities.Excluding cost,all of the alternatives have one or more
implementation barriers,such as:obtaining long-term agreements with property owners;)
obtaining operating permits;and overcoming poor or unknown construction conditions.As
Isuch,some wastewater management alternatives will be more likely than others regarding
their ability to actually be implemented.
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Design Criteria
I The design criteria described below form the basis for alternative evaluation and system
planning.
IFlows and Pollutant Loads
Table 1 summarizes the projected flows and pollutant loads for development and screening
of initial alternatives for planning within the 20-year planning period horizon.The flows
I and pollutant loads in Table 1 represent values expected at the City's Wastewater Treatment
Plant(WWTP)when using a 3.5 percent per year population growth scenario,and an
average contribution of 136 gallons per capita per day per year(300 gallons per equivalent
' dwelling unit per day).The flows and pollutant loads in Table 1 represent values expected
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EVALUATION OF WASTEWATER MANAGEMENT ALTERNATIVES
at the WWTP assuming that all but 4 percent of the dwellings within the service area are
connected to the central sewer and the WWTP.The 4 percent reduction accounts for
I dwelling units in rural residential and rural estate zoning areas that will not likely be served
by central sewer and the City WWTP in the future.
I TABLE 1
Flow and Pollutant Load Projections for 3.5 Percent Growth Scenario Using 136 gpcpd and 4 Percent Reduction in
Sewered Population
1 2013 2017 2018 2023 2033
Population 11,243 12,902 13,354 15,840 22,358
111 Flows(mgd)
Minimum Hour 0.6 0.7 0.7 0.9 1.2
Minimum Day 0.8 0.9 1.0 1.1 1.6
IMinimum Month 1.0 1.1 1.1 1.3 1.9
Average Daily 1.5 1.8 1.8 2.2 3.0
I Maximum Month 2.9 3.3 3.4 4.1 5.7
Maximum 7-day 3.4 4.0 4.1 4.9 6.9
Maximum Day 4.1 4.7 4.9 5.8 8.2
Peak Hour 5.0 5.7 5.9 7.0 9.9
BOD(ppd)
I Average Daily 2,877 3,301 3,417 4,053 5,721
Maximum Month 3,740 4,292 4,442 5,269 7,438
Maximum 7-day 4,316 4,952 5,126 6,080 8,582
TSS(ppd)
Average Daily 2,877 3,301 3,417 4,053 5,721
3 Maximum Month 3,740 4,292 4,442 5,269 7,438
Maximum 7-day 4,316 4,952 5,126 6,080 8,582
TKN(ppd)
1 Average Daily 448 514 532 631 890
Maximum Month 582 668 691 820 1,157
Maximum 7-day 671 770 797 946 1,335
Total Phosphorus(ppd)
Average Daily 102 117 121 144 203
IMaximum Month 133 153 158 187 264
Maximum 7-day 153 176 182 216 305
I gpcpd=gallons per capita per day
mgd=million gallons per day
ppd=pounds per day
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AL ATI EV U ON OF WASTEWATER MANAGEMENT ALTERNATIVES
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The planning periods in Table 1 are important to note,as follows:
I . Year 2013 is the first year in the planning period and the first year of operation of any
new facilities.
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Year 2017 is significant because that is the first year of operation after the term of the
agreement between the City and the J-Ditch Pipeline Association expires.
• Year 2018 is the fifth(5th)year of the 20-year planning period.
I • Year 2023 is the tenth(10th)year of the planning period and 2033 is the twentieth(20th)
year of the planning period.
Special Handling for Industrial Wastes/Pretreatment
The development and screening of initial alternatives assumes there will be no need for any
I special requirements for industrial wastes.It is assumed that industrial pretreatment will be
provided if needed to make industrial discharges compatible with the City's WWTP.
I Evaluation Criteria
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The criteria in the following text are used to evaluate the alternatives.
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Local Control
111 Local control of the wastewater management system for the City and its customers is a
criterion.Following are two examples:
iii • The City owns its wastewater management system.Ownership of all components of
the wastewater management system would give the City a high degree of control.
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• The City has a say in management and implementation.In lieu of ownership,
1 agreements between entities could give the City a say in implementation and
management of the wastewater system,but a lower degree of control.
I Effects on McCall and Neighborhoods
The degree to which a wastewater management system will impact McCall and its
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neighborhoods is a criterion.The effects may be long-term or short-term as noted below:
I • The effects of wastewater management facilities on residences and neighborhoods.
Impacts resulting from noise,odor,aesthetics,and traffic may impact the quality of life
for nearby residences,and some alternatives may have more impacts than others.
• Short-term Impacts of Plant and/or Pipeline Construction.In the short term,plant and
pipeline construction will be disruptive.However,depending on the neighborhood and
the location of the facilities to be constructed,some alternatives may be more disruptive
than others.
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EVALUATION OF WASTEWATER MANAGEMENT ALTERNATIVES
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IEffects on Other Jurisdictions
I/ Alternatives may affect both positively and negatively on areas of Valley County that are
outside of the City.Following are two examples:
. Effects of wastewater management facilities on county residences.Impacts resulting •
Ifrom noise,odor,aesthetics,and traffic may impact the quality of life for county
residents who are not served by the City's wastewater management system.
I . Short-term impacts of plant and/or pipeline construction.In the short term,plant and
pipeline construction will be disruptive for County residents who are not served by the
City's wastewater management system.Also,some alternatives may be more disruptive
1 than others.
Cost
I These include all the costs(engineering,construction,operation,and maintenance costs)
described as follows:
I . Capital costs.These are costs associated with building new facilities or improving or
expanding existing facilities.
., • Operation and maintenance costs.These are costs associated with operating and
maintaining new facilities or improving or expanding existing facilities.Typically,these
costs include labor,power,chemicals,equipment maintenance,and equipment
replacement.
• Life-cycle cost.These are long-term costs associated with an alternative that includes
both the initial capital outlay for engineering and construction,as well as for annual
111 operation and maintenance costs that are compared on a life-cycle basis.
Planning Flexibility
1 Some alternatives would give the City greater flexibility to adapt to new or changing
conditions,which in turn provide the ability to add components to meet needs for capacity.
iTreatment Process Flexibility
Some alternatives include treatment processes that would give the City greater flexibility to
adapt to new or changing regulatory requirements.
Implementation
ISome alternatives provide for greater ease and timeliness of implementation in terms of
design,permitting,and construction.Difficult permitting and regulatory environment,
I unique technology selection,or poor construction conditions may all contribute to delays in
implementation as follows:
• Legal arrangements.Some alternatives may require legal arrangements between the
City and other entities and make them more difficult to implement.
• Regulatory requirements.Some alternatives may challenge the current regulatory
framework and present difficult permitting conditions.
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• Proprietary technology.Some alternatives mayinvolve the use of proprietary P �'Y gY P P etary
technology that may be more difficult to procure.
I • Construction conditions.Poor or unknown construction conditions may create a more
risky situation and delay implementation.
I Long-Term Viability
Some alternatives may have greater potential to provide a long-term solution than others,
I making them more favorable.For instance,facilities located in areas with limited economic
prospects are less likely to come under economic pressure to be replaced.Conversely,a
need for additional industrial land could create pressure to move the facilities at a later date.
ICommunityAcceptance p ce
Some alternatives may have greater potential for community acceptance than others,
making them more favorable.For example,alternatives that are consistent with the local
vision and planning would be more likely to be acceptable.
IPotential to Create an Environmental Benefit
Some alternatives may present greater potential for providing environmental benefit,such
Ias reuse.
Economic Evaluation Methodology
II The design criteria described below form the basis for alternative evaluation and system
planning.
I Construction,operation and maintenance,and salvage-value cost opinions (values
associated with product end-of-life)were developed to allow comparison of alternatives for
the short-and long-term planning period.
The cost estimates are Class 4 Estimates,which are prepared based on limited information,
where the preliminary engineering is from 1 to 5 percent complete.Detailed strategic
ii planning,business development,project screening,alternative scheme analysis,
IIconfirmation of economic and or technical feasibility,and preliminary budget approval are
needed to proceed.Examples of estimating methods used would be equipment and or
I system process factors,scale-up factors,and parametric and modeling techniques.The
development of this type of estimate requires more time expended in its development.The
expected accuracy ranges for this class estimate are minus 15 to minus 30 percent on the low
side,and plus 20 to plus 50 percent on the high side.
These estimates are to be used onlyfor comparing initial conceptual alternatives for the
purpose of screening them to a reasonable few for further evaluation.These cost estimates
I should not be used for financial planning or rate impact analysis.
Capital Costs
ICapital costs are based on projected flows and pollutant loads for the planning period under
consideration.All capital costs include facilities sized for the 20-year planning period sized
IIfor 2033 flows and loads.All capital costs are in 2006 dollars.
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All construction costs include the construction direct costs without markups,a construction
direct cost markup allowance for the contractor's field detail,mobilization,bonds,permits,
I insurance,and overhead and profit of 27.34 percent.They also include a construction design
level contingency of 30 percent.The sum of these costs is the total construction cost.
In addition to construction costs,a non-construction cost allowance of 35 percent is added to
Ithe construction cost total to account for engineering,design,permitting,owner's legal and
administration,and construction management.
For alternatives where additional land is required to be purchased,the cost for the land is
added as the sum of the purchase price for land,with a 5 percent allowance for
administration and legal costs.
IThe total construction cost,the total non-construction cost,and the total land cost are
summed up to obtain the total project cost.Total project costs are rounded to the nearest
I $100,000.
Operation and Maintenance Costs
IOperation and maintenance costs are based on the following factors:
• Labor(average) :$32.00 per hour
• Power:$0.056/kilowatt-hour
• Ferric Chloride(40%):$372/dry ton
• Sodium Hypochlorite(12.5%):$1,522/dry ton
I . Liquid Polymer:$2,020/dry ton
Operation and maintenance costs are in 2006 dollars and are estimated for 2013 flows and
pollutant loads,because 2013 is the first full year the O&M costs will be incurred.O&M
costs are increased each year of the planning period by the same rate increase as population
projections,if they related to increase in flows and pollutant loads.Some O&M costs may
remain constant over the planning period.
Salvage Values
I Different components of a wastewater conveyance,treatment,and disposal system have
different useful lives.Therefore,present worth-analysis include salvage value for a
component within the planning period for a component that has a useful life less than the
I panning period plus a salvage valued for the replaced component.
bystraight-line
Salvage values are calculateddepreciation based on their remaining P useful
life at the end of the planning period.The only component of a facility that may not
IIdepreciate or appreciate is land.It is expected to have an infinite life;therefore,the salvage
value for the land is equal to its purchase price.
IDiscount Rate
Currently,capital improvements can be financed at an interest rate of about 6 percent per
year.As of early 2006,inflation is about 3 percent per year.The real value of money is the
111 interest rate less the inflation rate,or about 3 percent per year.The present-worth analyses is
based on a real discount rate of 3 percent per year.For this analysis,capital,operation and
maintenance costs,and salvage values are not inflated beyond 2006 dollars.
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Present-Worth Analysis
Initial capital expenditures are made in 2013.Therefore,these costs are brought back to 2006
Iby applying a single-payment present-worth(P,)factor for a period of 6 years,where the
discount rate is 3 percent.Other capital expenditures that may occur within the planning
I periods are brought back in the same manner,depending on when they occur.
The present worth of operation and maintenance costs is estimated with a geometric series
present-worth factor,using an operation and maintenance growth rate consistent with
I population projections,and a discount rate of 3 percent.This factor brings operation and
maintenance costs back to 2013;then they are brought back to 2006 with a single-payment
present-worth factor.
IThe salvage value is applied to the end of the planning period and brought back to 2006 by
applying a single payment present worth factor for a period of 27 years.The discount rate is
I 3 percent.
Present worth is defined as:
PW=Pw(capital) +Pw (Operation and Maintenance)—Pw (salvage)
Wastewater Management Alternative 1 (D2-S1-T5)
I Wastewater Management Alternative 1 combines the following:
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I . Effluent Disposal Alternative D2:Continue J-Ditch irrigation using unblended treated
wastewater
• Storage Alternative Sl:Provide additional liquid storage
• Treatment Alternative T5:Increase capacity of the existing plant and upgrade it such
that it can produce Class B effluent.
Figure 1 shows a wastewater treatment/disposal flow diagram associated with
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Alternative 1.Figure 2 is a site plan associated with Alternative 1.
IEffluent Disposal—Continue J-Ditch Irrigation Using Unblended Treated Wastewater
With Alternative 1,the use of the J-Ditch system would be retained;however,no blending
of treated wastewater with Lake Irrigation District water would occur.One of the J-Ditch
irrigation pipelines would be used to carry 100 percent treated wastewater.However,it is
noted that the underlying agreements for its operation effectively expire at the end of the
2016 irrigation season,and may or may not be renewed.To implement this alternative,it
would be necessary to not only extend the agreements between the parties,but it would also
be necessary to make a fundamental change from using blended irrigation water to
I100 percent treated wastewater.
In addition,because the J-Ditch irrigation practice would no longer comply with the terms
I of the Second Amended Consent Order,it is expected that DEQ would require that land
application permits be obtained pursuant to IDAPA 58,Title 01,Chapter 17 of the
administrative rules of DEQ to operate the J-Ditch in this manner.
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EVALUATION OF WASTEWATER MANAGEMENT ALTERNATIVES
In this alternative,effluent disposal would be accomplished through the continued
operation of the J-Ditch system,using 100 percent treated wastewater in one of the J-Ditch
pipelines.A total of 2,459 acres of land would be required to accommodate the projected
flows in 2033.This is approximately the same acreage as was initially identified for the
33.3 percent blended water J-Ditch pipeline system.Therefore,additional laterals to
I additional property owners would likely be needed,but the J-Ditch blended pipeline was
originally designed to accommodate that kind of acreage.
It is assumed that a new pump station and transmission line will provide additional
capacity to deliver additional water to the J-ditch pipeline.
Provide Additional Liquid Storage
For Alternative 1,the additional liquid storage would be added in a manner similar to the
existing winter storage pond.Approximately 564 million gallons of additional liquid storage
I would provide the additional capacity that is needed during the planning horizon.Storage
would be provided in two additional winter storage ponds,both of which are similar in size
' and depth as the current winter storage pond.The two storage ponds will each have a
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volume of 282 million gallons and provisions for 3 feet of freeboard.The volume is based on
an irrigation season from July 1 through September 15.Side slopes will be 3:1 (horizontal to
'' vertical).Operating depth will be 53 feet.It is assumed that the storage lagoons will be
I constructed on relatively flat ground and that cuts and fills will balance.The ponds will
have an under drain systems similar to the existing storage pond located to the south of the
3 treatment plant.The total area necessary for each pond (taking the toe of the berm as the
Ioutside boundary)is 27 acres.It is assumed that each pond will require 1 mile of pipe to
convey treated wastewater from the treatment plant to the storage pond.The under drain
system is similar to the existing storage pond.
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Increase Treatment Capacity of the Existing Plant and Upgrade it such that it can
Produce Class B Effluent
IAlternative 1 includes a Class B effluent to provide irrigation water for the effluent disposal
option.Conditions necessary for the protection of the public heath and the environment
I may differ from facility to facility.As such,specific permit conditions are expected to be
prepared on a case-by case basis that consider the chemical,biological,physical,and
volumetric characteristics of the wastewater,as well as the geologic and climatic nature of
Ithe land application sites.A limit on total nitrogen and total phosphorus is not assumed.
An evaluation of the existing WWTP was completed in previous studies by CH2M HILL.
I These studies concluded the capacity of the existing WWTP was capable of treating a
maximum month flow of 2.0 million gallons per day(mgd)and an associated peak
instantaneous flow of 4.75 mgd.To meet the 2033 design year criteria of a maximum month
flow of 5.7 mgd,significant modifications will be required to the existing WWTP.A detailed
I evaluation of unit processes is not provided in this facility plan,but a review of the existing
features compared to a traditional activated sludge treatment process is presented.To meet
the Class B criteria,secondary treatment followed by coagulation,filtration,and disinfection
I is required.
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IAerated Lagoon with Filtration
The use of the existing aerated lagoons,expanded as required to meet the 2033 design flow
and loads,was evaluated.The existing plant utilizes aerated facultative lagoons in series;
non-aerated facultative lagoon;intermittent sand filters;and disinfection with sodium
hypochlorite.Table 2 lists the unit processes currently utilized at the existing WWTP.
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TABLE 2 ,
City of McCall:Existing Wastewater Treatment Facility Unit Processes and Major Equipment
IProcess Description
Influent Flow Measurement (1)9-in Parshall Flume
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II Screening (1)Manual Bar Screen
Lagoon System (1)6.25-Mgal Aerated Facultative Lagoon,9-ft deep
(1)9.25-Mgal Aerated Facultative Lagoon,5-ft deep
I (1)3.25-Mgal Facultative Lagoon(Non-aerated),5-ft deep
Aeration Blowers (3)1,100-scfm,75-HP Centrifugal Blowers
ISand Filters (5)1-acre intermittent sand filters
Disinfection System (2)0.1-Mgal Chlorine Contact Chambers
(1)Sodium Hypochlorite On-site Generation System
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(2)Chemical Feed Pumps
Control Building This building houses the administration facilities,laboratory
equipment,and blower room
11 For the WWTP to provide a 5.7-mgd maximum month capacity,a significant expansion of
the existing lagoons and intermittent sand filters would be required.
• Additional Aerated Facultative Lagoon System:7.0-million—gallons covering 3.3 acres
(requires partitioning of existing lagoons along with a significant increase in aeration
capacity)
II • Additional Intermittent Sand Filters:Six, 1-acre Filters
• Expansion of existing Disinfection System:New chlorine contact channel along with the
Irequired expansion of the existing onsite sodium hypochlorite generation system
• The existing WWTP site technically has the area required for the expansion of the
I existing system.A number of issues remain,however,in maintaining the existing
treatment scheme.
• Reliability in reducing TN,if required in the future
I • Use of the existing intermittent sand filters to meeting IDEQ Class B standards year
round would be problematic due their inoperability during cold weather.In addition,
I new Class B treatment systems are required to be pilot tested and approved by IDEQ
prior to startup
• Limits future treatment expansion alternatives
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Because these limitations are related to the continued use of the existingsystem,expanding
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the capacity of the treatment plant with a different treatment process is recommended.
1 Traditional Activated Sludge Process
A traditional activated sludge process is sized to accommodate the expansion of the WWTP
Ito provide treatment for the 2033 design conditions.A number of traditional activated
processes are available to provide treatment at the McCall WWTP,but the evaluation of
multiple treatment configurations is beyond the scope of this Facility Plan.Future design
projects will provide the required configuration evaluation.For this evaluation,it is
assumed that an extended air,activated sludge (EAAS)process is used to provide
secondary treatment.The initial selection criteria for this treatment configuration are:
• Good flexibility for future TN removal with the additional of anoxic selectors
• TP removal not required,so biological and/or phosphorus removal not implemented
I • Primary clarifiers are not included
• Aerobic digestion of waste activated sludge
• Existing WWTP site has adequate land for this expansion
I I . Simple operation for an activated-sludge facility
• Accommodates tertiary filtration
• Assumes flow equalization is utilized,sized for 3.0 mgd average daily capacity
ITable 3 includes the conceptual sizing for the unit processes associated with the EAAS
facility.Figure 3 provides a process flow diagram of the proposed WWTP expansion for
I Alternative 1.Figure 4 provides a site plan for the proposed WWTP expansion for
Alternative 1.
I TABLE 3
Treatment Expansion Concept for Alternatives 1 and 2
Process Description
1 Screening (2)Automated Fine Screens
Grit Removal (2)Vortex-type grit removal systems
I Extended Air,Activated Sludge Aeration Basins (2)3.0-Mgal Aeration Basins
Secondary Clarifiers (2)90-ft Diameter Secondary Clarifiers
I Tertiary Filtration Granular Media Filters(6 cells)
Disinfection System (4)0.1-Mgal Chlorine Contact Chambers
Expanded Sodium Hypochlorite On-site Generation System
ISludge Stabilization Aerobic Digestion
Biosolids Dewatering Belt Filter Press System
Miscellaneous Systems Expansion to the administration facilities,laboratory
equipment,blowers,and maintenance facilities required
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ICosts
I Table 4 presents the project costs for Alternative 1.The total project cost to implement this
treatment alternative is estimated to be$88.5 million.Annual O&M costs are estimated to be
$1.81 million.The present worth of Alternative is estimated to be$109.3 million.
ITABLE 4
Estimated Costs for Alternative 1
Capital 0&M Present Worth
I Effluent Disposal $4.3 $0.18 6.4
Storage $33.5 $0.13 35.0
ITreatment $50.7 $1.5 $67.9
Total $88.5 $1.81 $109.3
IAll costs in millions of dollars.
1 Wastewater Management Alternative 2 (D5-S1-T5)
Wastewater Management Alternative 2 combines the following:
• Effluent Disposal Alternative D5:Abandon J-Ditch Irrigation and provide City owned
land irrigation using unblended treated wastewater
I • Storage Alternative S1:Provide additional liquid storage
III
• Treatment Alternative T5:Increase capacity of the existing plant and upgrade it such
Ithat it can produce Class B effluent.
Figure 5 is a wastewater treatment/disposal flow diagram for Alternative 2.Figure 6 is a
111 site plan associated with Alternative 2.
Effluent Disposal—Abandon J-Ditch Irrigation and Provide City-Owned Land
I/ Irrigation Using Unblended Treated Wastewater
With Alternative 2,all of the treated wastewater would be applied without dilution to
City-owned land.Accordingly,the City's treated wastewater would not be utilized in
Iconjunction with the J-Ditch system after year 2016.The new City-owned lands that come
under irrigation with treated wastewater would require land application permits in
accordance with DEQ regulations.
iA total of 1,697 irrigated acres of City-owned land would be required to satisfy the projected
flows in year 2033.Placing this land under irrigation would also require a modification of
I the existing or a new effluent pumping and pipeline system dedicated to the new
City-owned lands.It is assumed that the new storage ponds would share a common pump
station and transmission line which will deliver water to the City-owned land.It is further
I assumed that the City-owned land will require a pipeline similar in lengths and diameters
to the existing J-ditch enriched main,and a similar number of turnouts.
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EVALUATION OF WASTEWATER MANAGEMENT ALTERNATIVES
IProvide Additional Liquid Storage
I For Alternative 2 the additional liquid storage could be added in a like manner as the
existing winter storage pond.Approximately 384 million gallons of additional liquid storage
would provide the additional capacity that is needed during the planning horizon.For this
I comparison,the storage would be provided in two additional ponds.Note that these
storage ponds are smaller than the storage ponds in Alternative 1.Two storage ponds will
be provided and each will have a volume of 192 MG and provide 3 feet of freeboard.The
I volume is based on an irrigation season from May 15 through September 15.Side slopes will
be 3:1.Operating depth will be 53 feet. It is assumed that the storage lagoons will be
constructed on relatively level ground and that cuts and fills will balance.The ponds will
I have under drain systems similar to the existing storage pond located to the south of the
WWTP.The total area necessary for each pond(taking the toe of the berm as the outside
boundary)is 26 acres.It is assumed that each pond will require 1 mile of pipe to convey
I water from the WWTP to the pond.The under drain system is similar to the existing storage
pond.
I Increase Treatment Capacity of the Existing Plant. Upgrade it to Produce 3 mgd of
Class B Effluent
Alternative 2 also includes a Class B effluent to provide irrigation water for the effluent
P disposal option.Conditions necessary for the protection of the public heath and the
environment may differ from facility to facility.As such,specific permit conditions are
expected to be prepared on a case-by-case basis considering the chemical,biological,
Iphysical,and volumetric characteristics of the wastewater,as well as the geologic and
climatic nature of the land application sites.However,a TP limit is not assumed.
I The same treatment scheme proposed for Alternative 1 is also proposed for Alternative 2.
Table 3 (provided previously)includes the conceptual sizing for the unit processes
associated with the EAAS facility.
ICosts
Table 5 presents the project costs for Alternative 2 The total project cost to implement this
i treatment alternative is estimated to be $132.2 million.Annual O&M costs are estimated to
be$1.86 million.The present worth of Alternative is estimated to be$153.6 million.
I TABLE 5
Estimated Costs for Alternative 2
Capital 0&M Present Worth
IEffluent Disposal $55.4 $0.23 58.0
Storage $25.9 $0.13 27.7
ITreatment $50.7 $1.5 67.9
Total $132.0 $1.86 153.6
All costs in millions of dollars.
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EVALUATION OF WASTEWATER MANAGEMENT ALTERNATIVES
II Wastewater Management Alternative 3 (D13-SO-T11)
IWastewater Management Alternative 3 combines the following:
• Effluent Disposal Alternative D13:Rapid infiltration with ground water and surface
Iwater influence.
• Storage Alternative SO:Utilize existing storage
I I . Treatment Alternative T11:Replace the existing plant to produce Class B effluent with
total phosphorus(TP)less than 0.1 mg/L,and total nitrogen(TN)less than 10 mg/L.
I Figure 7 is a wastewater treatment/disposal flow diagram for Alternative 3.Figure 8 shows
a site plan associated with Alternative 3.
I Effluent Disposal Using Rapid Infiltration with Surface and Groundwater Influence
Effluent Disposal Alternative D13 is a rapid infiltration system that is assumed to impact
both groundwater and surface water.For this alternative it may be necessary to issue a
I NPDES permit and a Wastewater Land Application Permit.If EPA issues a NPDES permit,
it could be possible to include monitoring and permit limits for groundwater concerns in the
NPDES permit.
IThis current analysis is based in part on results from a DEQ evaluation of the North Lake
Recreational Water and Sewer District's(North Lake)rapid infiltration basin(R1 site No. 1).
I The DEQ evaluation focused on RI site No. 1,which indicated that land was covered by the
following NRCS soil types:Donnel sandy loam and Kangas fine gravelly loamy coarse sand.
Infiltration rates were measured in four test pits at RI site No. 1.The effective infiltration
Irates in the pits ranged from 3 to 1,400 inches per hour.
A portion of the McCall impact area is shown in Figure 8,alongwith soils classified as
P
Donnel sandy loam by the NRCS.Although the potential exists for infiltration rates through
Ithis soil type to be similar to the soils at the RI site No. 1 location at North Lakes,field data
must be collected to determine the effective infiltration rate of potential rapid infiltration
pond locations.
1 The conceptual rapid infiltration facility consists of a fenced area containing 10 rapid
infiltration basins.Each rapid infiltration basin contains an infiltration area of 3.4 acres with
I a total depth of 6 feet.An additional 7 acres is needed for roads,berms,and equipment
storage at the site.The facility will be sized such that it can be taken out of service for up to
2 months each year while treated effluent is diverted to the existing storage pond.This
I feature will alleviate problems with freezing in the infiltration basins.The basins will be
loaded on average once every 18 days at 72 inches/day such that the basins will contain
water for 24 hours followed by an average 17 days to dry out.Final sizing of the system will
I depend on extensive soil investigation.The system may be much larger or smaller than this
estimate.Operation and maintenance includes the annual tillage of the infiltration basin
surface,and the maintenance and repair of dikes,fences,and roads.
IThe existing pump station that is currently used to convey treated effluent from the
treatment plant to the J-Ditch mixing station will be used instead to convey treated effluent
I
IB01063470039.00C/KM 13
1
EVALUATION OF WASTEWATER MANAGEMENT ALTERNATIVES
to the rapid infiltration facility.The new transmission main will be approximately 8,200 feet
in length.
I
Replace ExistingPlant to Produce 3 mgd of Class B Effluent with Total
g
Phosphorus Less than 0.1 mg/L and Total Nitrogen Less than 10 mg/L
IUnder Wastewater Management Alternative 3 the existing treatment plant would be
replaced with a new plant.The new capacity would treat an average of 3.0 million gallons
Iper day to the Class B level.
For Wastewater Management Alternative 3,the effluent must be treated to level
accommodating discharge to rapid infiltration system with a direct influence on surface
Iwater or ground water.Effluent quality would be such that effluent BOD and TSS average
less than 10 mg/L,effluent total phosphorus averages less than 0.1 mg/L,and total nitrogen
averages less than 10 mg/L.In addition,turbidity would be less than 2 NTU as a daily mean
Iand not exceed 5 NTU at any time.As with the evaluation of treatment for Alternatives 1
and 2,this conceptual analysis does not consider all of the treatment configurations capable
III of meeting the associated effluent criteria.The system developed for the initial,conceptual
consideration for Alternatives 3 and 4 is a membrane bioreactor system.
• Membrane Bioreactor Activated Sludge System
1 A membrane bioreactor(MBR)activated sludge system will provide the required treatment
to meet the criteria of Alternative 3.The system is initially designed to include biological
nutrient removal to meet the associated treatment goals.MBR systems typically cannot
I
address higher peaking factors common at some treatment facilities.For the McCall system,
it is assumed that the existing aerated lagoon system can be re-designed to provide flow
II equali7ation prior to secondary treatment.With this feature in the system,the MBR
secondary treatment system can be designed for 3.0 mgd instead of the 5.7-mgd maximum
flow/average daily flow.The equali7ation volume will minimize any flow events larger
Ithan 3.0 mgd.Additional selection criteria for this treatment configuration are:
• Good TN removal with anoxic selectors
II . Excellent TP removal with the addition of anaerobic selectors (for inorganic soluble
phosphorus),and the use of membrane filtration for high TSS removal(and the
associated particulate phosphorus)
I • The addition of chemicals to optimize phosphorus removals is also included
• No primary clarifiers are included
I • Aerobic digestion of waste activated sludge
• Existing WWTP site has adequate land for this expansion
I • Tertiary filtration is not required,because Class B effluent is created with an MBR
I . Flow equalization required,use of existing lagoons available
• Future expansion capabilities
I
I801063470039.00CIKM 14
1
EVALUATION OF WASTEWATER MANAGEMENT ALTERNATIVES
I Table 1 6 includes
c udes the conceptual sizing for the unit processes associated with the MBR
facility.
IITABLE 6
Treatment Expansion Concept for Alternatives 3 and 4
IProcess Description
Screening (2)Automated Fine Screens
IGrit Removal (2)Vortex-type grit removal systems
In-Plant Pump Station Pumping System from Equalization Basins
I Membrane Bioreactor,Activated Sludge Aeration (2)1.0-Mgal Aeration Basins providing BNR,including
Basins Membrane System
Disinfection System (4)0.1-Mgal Chlorine Contact Chambers
I Expanded Sodium Hypochlorite On-site Generation
System
Sludge Stabilization Aerobic Digestion
IBiosolids Dewatering Belt Filter Press System
Miscellaneous Systems Expansion to the administration facilities,laboratory
Iequipment, blowers,and maintenance facilities required
IFigure 9 includes the process flow diagram for the MBR treatment system for Alternative 3.
Figure 10 provides a site plan for the proposed WWTP expansion for Alternative 3.
ICosts
Table 7 presents the project costs for Alternative 3.The total project cost to implement this
I treatment alternative is estimated to be$72 million.Annual O&M costs are estimated to be
$2.01 million.The present worth of Alternative 3 is estimated to be$95.1 million.
I TABLE 7
Estimated Costs for Alternative 3
Capital 0&M Present Worth
Effluent Disposal $13.5 $0.41 $18.2
Storage $0 $0 $0
I Treatment $58.5 $1.6 $76.9
Total $72.0 $2.01 $95.10
All costs in millions of dollars.
Wastewater Management Alternative 4 (D14-SO-T11)
I
Wastewater Management Alternative 4 combines the following:
g g
1 • Effluent Disposal Alternative D14:Discharge to the North fork of the Payette River
IB01063470039.DOC/KM 15
1
k
EVALUATION OF WASTEWATER MANAGEMENT ALTERNATIVES
• Storage Alternative SO:Utilize existing storage
I . Treatment Alternative Ti l:Replace the existing plant to produce Class B effluent with
total phosphorus (TP)less than 0.1 mg/L,and total nitrogen(TN)less than 10 mg/L.
is A wastewater treatment/disposal flow diagram for Alternative 3 is presented in Figure 11,
Iand a site plan is shown in Figure 12.
Effluent Disposal with Surface Water Discharge to the North Fork of the Payette
IRiver
Alternative 4 discharges treated wastewater to the North Fork of the Payette River.Under
I this alternative,wastewater is treated to a level necessary to support the designated uses of
the surface water.Numerous wastewater treatment scenarios are available depending on
the background water quality of the surface water and federal and state discharge
I requirements.EPA prepares permits to regulate the discharge to surface waters in Idaho.
DEQ certifies that the permit will satisfy the state's water quality criteria if the discharge
and the permit are implemented.
IThis alternative could be combined with other alternatives to reduce or eliminate the
discharge to the river during the summer irrigation months or extended seasons through a
I continuation of the current J-Ditch operation and/or other reclaimed wastewater effluent
disposal alternatives.
The level of treatment required would be controlled by an NPDES permit.The treatment
1 assumption used for comparing the alternative is that the effluent total phosphorus
discharge to the River would be less than 0.1 mg/L,and the total nitrogen would be less
than 10 mg/L on a monthly average basis.To comply with these effluent limits,the actual
Idesign and operation of the plant would require that effluent phosphorus and nitrogen
concentrations be lower than the compliance limits.
I Replace Existing Treatment Plant to Produce 3 mgd of Class B Effluent with Total
Phosphorus Less than 0.1 mg/L and Total Nitrogen Less than 10 mg/L
I With a discharge to the North Fork of the Payette River,a primary treatment objective
would be to remove as much phosphorus as practicable to reduce the impact on the North
Fork of the Payette River and Cascade Lake.Although this alternative is developed to
I function by itself(complete treatment and discharge of all flows the River),it would be
possible to combine the alternative with other effluent disposal alternatives to capture the
use of the existing facilities to the extent practicable.
IThis alternative abandons the existing plant and replaces it with a new WWTP such that it
can treat an average daily flow of 3 million gallons per day with phosphorus to levels that
are consistently less than 0.1 mg/L.
For Wastewater Management Alternative 4,the effluent must be treated to a level
accommodating discharge to systems with a direct influent on surface water or to a
Ireceiving stream.It is assumed that the effluent must have a TN less than 10 mg/L and a TP
less than 0.1 mg/L.As with the evaluation for Alternatives 1 and 2,this conceptual analysis
does not consider all of the treatment configurations capable of meeting the associated
1
801063470039.DOC/KM 16
k
EVALUATION OF WASTEWATER MANAGEMENT ALTERNATIVES
effluent criteria.
to a.The system developed for the initial,conceptual consideration for
Alternatives 4 is the same as for Alternative 3—a membrane bioreactor system.
ITable 6 includes the conceptual sizing for the unit processes associated with the MBR
facility.Figure 11 provides a process flow diagram of the proposed WWTP expansion for
I Alternative 4 and Figure 12 provides a site plan for the proposed WWTP expansion for
Alternative 4.
ICosts
Project costs for Alternative 4 are presented in Table 8.The total project cost to implement
this treatment alternative is estimated to be$58.5 million.Annual O&M costs are estimated
IIto be$1.6 million.The present worth of Alternative is estimated to be$76.9 million.
TABLE 8
IEstimated Costs for Alternative 4
Capital 0&M Present Worth
a Effluent Disposal $0 $0 $0
Storage $0 $0 $0
Treatment $58.5 $1.6 $76.9
I Total $58.5 $1.6 $76.9
All costs in millions of dollars.
I
No Action Alternative
IThe No Action Alternative would entail continued use of the existing McCall Wastewater
Management system including the conveyance and treatment facilities.The No Action
IAlternative would also include that the normal operation and maintenance activities for the
facilities would continue.The environmental impacts of the No Action Alternative will be
compared with the other alternatives in an environmental information document for the
I McCall Wastewater Facilities Plan that will be prepared in a subsequent step in the planning
process.
I
I
I
I
I
I/ B01063470039.DOC/KM 17
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MIR NS - IIIMI MID MI NM MIN NS IMO — all NM ON NMI SIB — 111.111
Existing Storage Pond
-,
\ z
Existing
Increase Capacity of I Pump Station
Existing Treatment Plant II
I [-Gil Existing Transmission Line
Treatment 91 I L 1 , Existing
Alternative 15 I J-Ditch J-Ditch
/-------- LGI- I
/ \j
(Increase capacity of the Mixing Station Pipelines
existing plant. Ill (Abandon)
_____>
New Storage Pond 1 lim 3 it to produce ,_ _1
New
3 MGD of Class B effluent) >111 % Pump Station(s) Disposal
Alternative D2
Storage
Alternative Soil
111111.0.
New Storage Pond 2
>1111T11
Storage
Alternative tal
1 PA s.
FIGURE 1
ALTERNATIVE 1(D2-S1-T5)
WASTEWATER TREATMENT/DISPOSAL FLOW DIAGRAM
City of McCall,Idaho
W8122006001 BOI CH21101HILL
-..,
Upgraded'
IL
ML
New 24"
Transmissiol
Lind
Stitch
lation
'itch Mixinq Statio.T
Influent Flow Screening Aeration Secondary Tertiary Effluent
Measurement —> Grit Removal �► 4% > Basins ^ > Clarifiers -� Filters —3 Disposal
, I I
V
Flow
Equalization
V
Aerobic —) Dewatering Biosolids
Digestion Disposal
FIGURE 3
EXPANSION ALTERNATIVES 1 AND 2
TREATMENT PROCESS FLOW DIAGRAM
EAAS CONFIGURATION
CM2MHILL
WB112006001601
M 1 w — S r N r — — — S NS an S an — r
-1 APpRo
21 N NORTH gA LO1:A 1)O/y
o ri ORROWW AREA
czQ:._-
.,,(\___,_
o ,n w NorYt
,� -, 0 t 100 t 200
i:.,
•
{� C) Headworks/ ,.� Approximate scale in feet
Grit Removal
fct
im‘
i7 0
'
_ OXIA E FINAL 7
l �_ `- _ °PSOIt, STOcKPOC p
T�ION Secondary
\ ( 40,000 cr) t Clarifiers
0- , / _...J,..-1 __. _
\ � �� 668.66'_.
(2) EARS Basins '1 4
/.7
1):
_ -- --- Tertiary 11
Filters i1Aerobic f/ ////
/
A\\a�
wo. Di 01"1gester _ _//
_ = __ I _I :( i
/;-_-_,:-_-_-_-_-_-_-____________
-----\\ ,,, I
lG J
-? _9
) k
°�� Dewatering --- ?' L - C -_ ,,''
n Building - — ���q .
Zvi . ° 1 2 IRON PIN 1 1 ha'
N 178230.57 Chlorine Contact
n mac'-\ t �_ E 404097.83 ;'�
Chemical Addition:
\ 2tE lILI__ n\••e.a, -37.11' \\\N„,__.) "--____ Eero ..a /
.86'
C� o. S89'54'08"E t
1� _ _ 'S4'G✓;`W &3iT2d'•
�B9s
�- tea' 334.26' FIGURE4
OE,BATCH fFj l"' �\ / `�� EXPANSION ALTERNATIVES 1 AND 2
I
EAAS CONFIGURATION(3 MGD)
o N City of McCall,Idaho
CHZ1111HILL
WB1 22006001 BOI
r — I INN INN M INN r — In — iliilllll I I — IIII■I r MI a MI
New City-Owned Land
Disposal
Alternative D5
Existing Storage Pond
� i 1 17,1
Increase Capacity of ----� I Existing
I Pump Station 7/
Existing Treatment Plant I I /
- I I I I 2/
Treatment I __
Alternative T5 I ____� I - I i New
(Increase capacity of existing ,�z~ N,J ` Transmission Line(s)> ,,_
plant. Upgrade it to produce New Storage Pond 1 ,
3 MGD of Class B effluent) '
,...y
�� New
� Pump Station(s) '
Storage >
Alternative S1 ,,
IP 1
7777'New Storage Pond 2
>'
Storage 4
Alternative S1
P II
FIGURE 5
ALTERNATIVE 2(D5-S1-T5)
WASTEWATER TREATMENT/DISPOSAL FLOW DIAGRAM
City of McCall,Idaho
CH2MHILL
WB122006001B01
INN SIN 11.11 11111 NS MIN — SU NM 11111 NIB NIB — INN NI NS NM 1111111
New Rapid
Infiltration Basins
Existing Storage Pond Disposal
Alternative 013
;,..-.)
\r-------/
Replace Existing I I UpgradedI I Pump Station
Treatment Plant I I I I
I I 1 dr New Transmission Line 4) 4. 4. 4, 4, 4. L,
Treatment +I I I L____>1
Alternative 111 I ._z _. I i y
Iz N j L fr
(Replace existing plant to ,‘
produce 3 MGD of Class B 4) 4, 4. 4. 4. 4.
effluent with total phosphorus
less than 0.1 mg/L and total Iliiiiiiiiiiiiiiit
nitrogen less than 10 mg/L) 4) 4, 4. 4. 4, 4. LO
FIGURE 7
ALTERNATIVE 3(D13-SO-T11)
WASTEWATER TREATMENT/DISPOSAL FLOW DIAGRAM
City of McCall,Idaho
C
WB1220060011301 H2IVIHILL
- , --.
NIP - M M M r - - - r r M UM M r M M - MS
r , , , r
Membrane
Influent Flow Screening Bioreactor —> Effluent
Measurement Grit Removal ---- System Disposal
V
Flow
Equalization
v
Aerobic Biosolids
Digestion —9 Dewatering —4 Disposal
FIGURE 9
EXPANSION ALTERNATIVES 3 AND 4
TREATMENT PROCESS FLOW DIAGRAM
MBR CONFIGURATION
WB122006001B01 CH2MHILL
NM NMI r I 611111 r IINII EN INN I NIIII INN I• N r NM I MI
M
`� NORTH ATE L01;gpON
o BORF?ow AREA
z .^ w Neslh
? �� ._,Ti -
;„ 0 i 100 ' 200
rI M I
n Approximate scale in feet
(�' f 1 Headworks/ �� --{�1;r
0}_ Grit Removal (-,
P,
/ FINAL 7pPSO�XwATE LOCATION
I
srocKPILE MBR System
( 40.00oI:_` • Aeration Basin
P--9
• MBR Trains' • Mechanical Building
' 0 7 — `�___ �-�_ _<ti^} )N8 '54'41"W
/ / i ------- r_________::_)
\ / // _
...__.::___ ___
, c___,, ,,,_• ..„_:___._..___
/,/
___________ / 1 I)
o //LI ///
/(__/ /
r i/
F.---„,,, -_-_-_7_ ---____
. ,.)"- ,i ___ .
7 ....-- -_ .., ,, cii_7 '''..."'
Digester _ _ /. _
l .-------) i
\''''0:
Dewatering ( jij � _ :C')_ `
n Building I --� -•a�� *f"'�
l 'CA
0 1/2 IRON PIN p8�6
_)_.} ----___:_____
i N 178230.57 / Chlorine Contact
r kii
pN-\ —,..-----*----__i_---___,_�E 404097.83 Chemical Additio
•
S$9 52'18"E U S8 2'18"E �` _____� J/'
___
. 37.11. H 382.86' ,3 `--�_-�. `_=i
of �" N'b,
0:N _._,. O�
p.. T(V
O'
S89'508"E oN
} � '54'08"W - 3 23' `:.........
�� <2:111 334.26' FIGURE 10
" A"' �\ —___-, EXPANSION ALTERNATIVES 3 AND 4
MBR CONFIGURATION(3 MGD)
I o City of McCall,Idaho
OHSMHILL
W8122006001801
INN MIN NM INN BM IIIIIII MIN MINI =III MB MN MN =III IIIIIII NMI II= VIII INS MI
North Fork
Existing Storage Pond Payette River
Disposal
Replace Existing Alternative D14
Treatment Plant I I I
I I Upgraded Transmission Line and Diffuser
Treatment +1I I
A )1\
Alternative 111
\,
(-- 1 //,-_ -
)
(Replace existing plant to
produce 3 MGD of Class B
effluent with total phosphorus
less than 0.1 mg/L and total
Y nitrogen less than 10 mg/L)
i/
)
/
FIGURE 11
ALTERNATIVE 4(D14-SO-T11)
WASTEWATER TREATMENT/DISPOSAL FLOW DIAGRAM
City of McCall,Idaho
2110
W13122006001601 C14 1HILL