WEST COUNTY AGENCY
Biosolids and Leachate Treatment Cost of Service and Maintenance Agreements Cost Analysis TECHNICAL MEMORANDUM 1
Biosolids Treatment Cost
FINAL / February 2025
WEST COUNTY AGENCY
Biosolids and Leachate Treatment Cost of Service and Maintenance Agreements Cost Analysis
TECHNICAL MEMORANDUM 1
Biosolids Treatment Cost
FINAL / February 2025
TM 1 – BIOSOLIDS TREATMENT COST
FEBRUARY 2025 / FINAL / CAROLLO
WEST COUNTY AGENCY
BIOSOLIDS AND LEACHATE TREATMENT COST OF SERVICE AND MAINTENANCE AGREEMENTS COST ANALYSIS i pw://Carollo/CA/WCW/203127-000000/03 Reports and Studies/02 Deliverables/TM01 - Biosolids Treatment Cost/TM01_BiosolidsTreatmentCost.docx Contents
TM 1 BIOSOLIDS TREATMENT COST
1.1 Introduction 1-1
1.2 Existing Biosolids Treatment Facilities 1-2
1.3 Cost Model Methodology 1-3
1.3.1 Capital Costs 1-3
1.3.2 Operation and Maintenance Costs 1-4
1.3.3 End-Use/Disposal Costs 1-8
1.4 Model Results 1-8
1.5 Analytical Monitoring Program 1-10
Tables
Table 1.1 Cost Model Inputs/Assumptions for Capital Costs 1-4 Table 1.2 O&M Unit Costs 1-5
Table 1.3 O&M Unit Cost Escalation Factors 1-5
Table 1.4 Cost Model Inputs/Assumptions for O&M 1-6
Table 1.5 Shared Biosolids Facilities Equipment 1-7
Table 1.6 O&M Escalated Unit Costs 1-9
Table 1.7 Total Cost Estimate Summary 1-9
Table 1.8 Agency Cost Allocation 1-9
Figures
Figure 1.1 Future Biosolids Treatment Process Flow Diagram 1-2 Figure 1.2 Recommended Analytical Sampling Locations 1-10
TM 1 – BIOSOLIDS TREATMENT COST
FEBRUARY 2025 / FINAL / CAROLLO
WEST COUNTY AGENCY
BIOSOLIDS AND LEACHATE TREATMENT COST OF SERVICE AND MAINTENANCE AGREEMENTS COST ANALYSIS ii Abbreviations
BODR Basis of Design Report
City City of Richmond Municipal Sewer District
gal gallon
hp horsepower
hr hour
kWh kilowatt-hour
MMBtu metric million British thermal units
NPDES National Pollutant Discharge Elimination System
O&M operations and maintenance
Project Biosolids and Leachate Treatment Cost of Service and Maintenance Agreements Cost Analysis Project
scfm standard cubic feet per minute
TM technical memorandum
WCA West County Agency
WCW West County Wastewater
WPCP water pollution control plant
WQRRP water quality resource and recovery plant
yr year
TM 1 – BIOSOLIDS TREATMENT COST
FEBRUARY 2025 / FINAL / CAROLLO
WEST COUNTY AGENCY
BIOSOLIDS AND LEACHATE TREATMENT COST OF SERVICE AND MAINTENANCE AGREEMENTS COST ANALYSIS 1-1 TM 1 BIOSOLIDS TREATMENT COST
1.1 Introduction
The West County Agency (WCA) was previously a joint powers authority between the City of Richmond Municipal Sewer District (City) and West County Wastewater (WCW). It was originally established in 1977 to provide more efficient wastewater treatment and sludge disposal for its service areas. Approximately three years ago, the WCA Board voted to dissolve the WCA and move forward with separate operating agreements between the City and WCW. The WCA dissolution officially became effective on January 1, 2025. Since the City and WCW jointly own certain assets and plan to continue shared operational activities in the future, the costs associated with these various activities require equitable allocation based on current and planned operations between the City and WCW. To estimate the costs and appropriate allocation of their operational activities, the City and WCW conducted a Biosolids and Leachate Treatment Cost of Service and Maintenance Agreements Cost Analysis Project (Project).
The assets presented in the following bullets are the WCA joint assets, which are separate components of a single system. That system combines and dechlorinates effluent from both the City’s and WCW’s facilities and conveys it to a point of discharge (i.e., the submarine outfall). According to the joint exercise of powers agreement amended and restated in November 2023, the WCA joint assets include the following:
Joint dechlorination facility (also known as sodium bisulfite dechlorination facility). Confluence structure.
Transmission pipeline from confluence structure to submarine outfall. Submarine outfall.
Outfall diffusers.
Aide-to-navigation marker buoys.
Cathodic protection system.
In addition to the WCA joint assets, three operational activities were evaluated as part of this Project due to their historical and operational relevance to the City and WCW. These operational activities resulted from agreements outside the WCA between the City, WCW, East Bay Municipal Utility District, and the Republic Services (West County) Landfill. The three operational activities include:
Biosolids management.
Landfill leachate treatment.
Contract lift station operations and maintenance (O&M).
Estimated costs for all activities between the City and WCW were developed and summarized in a series of technical memoranda (TMs) for this Project.
This TM summarizes the future estimated costs for biosolids management. These biosolids management costs include capital costs, O&M costs, and disposal costs for treating and disposing biosolids produced TM 1 – BIOSOLIDS TREATMENT COST
FEBRUARY 2025 / FINAL / CAROLLO
WEST COUNTY AGENCY
BIOSOLIDS AND LEACHATE TREATMENT COST OF SERVICE AND MAINTENANCE AGREEMENTS COST ANALYSIS 1-2 from both the WCW Water Quality Resource and Recovery Plant (WQRRP) and City of Richmond’s Water Pollution Control Plant (WPCP) using the newly constructed biosolids facilities at the WCW WQRRP.
1.2 Existing Biosolids Treatment Facilities
Figure 1.1 shows the process flow diagram of the future biosolids treatment train at the WCW WQRRP showing the shared process units that will treat both the City’s and WCW’s solids. For many years, sludge drying lagoons were used to store and dry WCW’s anaerobically digested biosolids and the City’s anaerobically digested biosolids sent to the WCW WQRRP via a 5-mile pipeline. However, WCW is currently undergoing the Clean and Green Project, an energy and sustainability project which will upgrade/add WQRRP process units, reduce greenhouse gas emissions, and minimize energy costs. This project will upgrade the WQRRP solids processes from the sludge drying beds to new centrifuges for dewatering and a thermal dryer for producing Class A biosolids.
Figure 1.1 Future Biosolids Treatment Process Flow Diagram Digested biosolids from the City’s WPCP (located at 601 Canal Boulevard) are pumped through an approximately 5-mile pipeline to WCW’s WQRRP (located at 2377 Garden Tract Road). Based on the Clean and Green Project design drawings and Basis of Design Report (BODR), the WCW digested biosolids will be blended with the City’s digested biosolids in two blending/storage tanks. Then the blended biosolids will be conveyed to the centrifuges with polymer injected into the centrifuge feed for optimal dewatering performance. Dewatered biosolids will be dried via a thermal dryer using a combination of natural gas and heat from WCW’s cogeneration combined heat and power system as energy sources. The produced Class A biosolids are to be hauled off site for beneficial use/disposal.
TM 1 – BIOSOLIDS TREATMENT COST
FEBRUARY 2025 / FINAL / CAROLLO
WEST COUNTY AGENCY
BIOSOLIDS AND LEACHATE TREATMENT COST OF SERVICE AND MAINTENANCE AGREEMENTS COST ANALYSIS 1-3 The following facilities will be used for treating and processing the combined or blended biosolids:
Blending/storage tanks (Tanks 103 and 104) and mixer. Centrifuges.
Thermal dryer.
Associated plumbing and monitoring/control elements.
Pipeline extension connecting the City’s existing 6-inch sludge line to the blending/storage tanks (to be constructed as part of the Clean and Green Project). Vehicles and equipment necessary for biosolids handling.
Each of these facilities requires O&M, which will be completed by WCW staff, and the produced Class A biosolids will require a cost for off-site hauling and beneficial use/disposal. Additionally, as identified by WCA, WCW and the City will share the capital cost of these shared components in a 60/40 split (the smaller percentage assigned to the City) amortized over 20 years. The following section describes the cost methodology for estimating these capital costs, O&M costs, and off-site biosolids management costs.
1.3 Cost Model Methodology
A cost model was developed to estimate capital costs, O&M costs, and off-site biosolids management costs for treating and disposing of WCA biosolids with the newly constructed WCW WQRRP biosolids facilities. Costs were estimated based on information provided by WCW and the City of Richmond (i.e., Clean and Green Project design drawings, Clean and Green Project BODR, etc.), available data, and engineering judgment. Also, the O&M and off-site biosolids management costs were escalated for the next 20 years (2025 to 2045) to capture potential market trends based on existing information. The following subsections describe the cost model methodology for estimating the capital, O&M, and off-site biosolids management cost components.
1.3.1 Capital Costs
Since the new solids facilities at the WQRRP will be used to process biosolids from both the WCW WQRRP and Richmond WPCP, WCW and the City have agreed to split the capital cost of the shared components (storage tank improvements, construction of the solids handling building, centrifuges, and belt dryer) 60/40 (WCW/City) amortized over a 20-year period. Equation 1 is a capital recovery equation for calculating the annual payment over a period of time at a fixed interest rate to recover the initial investment of a capital project. Table 1.1 lists the inputs and assumptions which were used to calculate the annual payment for each party.
Equation 1 – Capital Recovery
𝐴𝐴 = 𝑃𝑃 � 𝑖𝑖(1 + 𝑖𝑖)𝑛𝑛
(1 + 𝑖𝑖)𝑛𝑛 − 1�
Note: A – annuity; P – present value; i – interest rate; n – number of years.
TM 1 – BIOSOLIDS TREATMENT COST
FEBRUARY 2025 / FINAL / CAROLLO
WEST COUNTY AGENCY
BIOSOLIDS AND LEACHATE TREATMENT COST OF SERVICE AND MAINTENANCE AGREEMENTS COST ANALYSIS 1-4 Table 1.1 Cost Model Inputs/Assumptions for Capital Costs Cost Model Input Units Value Reference
Clean and Green Shared Assets Capital Costs
Sludge Centrifugal Dewatering System $ 3,981,725 Provided by WCW.
Sludge Thermal Dryer System $ 11,828,100 Provided by WCW.
Richmond Sludge Piping Upgrade $ 89,683 Provided by WCW.
Blending Tank (Tank 103) Mixing System,
Rehab, Structural Assessment
$ 680,055 Provided by WCW.
Total Capital Costs $ 16,579,563
Calculated Annuity Inputs
Years of Capital Return yr 20 Per project scope.
Interest Rate % 3 Assumed constant over period of capital return.
Calculated Capital Recovery Annuity $/yr 1,114,407 Calculated using Equation 1.
Annuity Distribution
WCW $/yr 668,644 Calculated as 60% of calculated capital recovery annuity.
City of Richmond $/yr 445,763 Calculated as 40% of calculated capital recovery annuity.
Notes:
yr – year.
Based on the information presented in Table 1.1, WCW and the City are responsible for paying approximately $670,000 and $450,000, respectively, every year over a 20-year period to fully recover the initial investment of the shared solids facilities from the Clean and Green Project.
1.3.2 Operation and Maintenance Costs
The sludge blending/storage tanks, centrifuges, and thermal dryer all require O&M. Unit costs were used in combination with cost model inputs and assumptions (i.e., operating schedules, polymer usage, sampling frequency, etc.) to estimate the annual O&M costs for the next 20 years.
1.3.2.1 Unit Costs
The O&M costs for treating WCW’s and the City’s biosolids and maintaining WCW’s solids facility equipment include the following categories:
Electric power.
Polymer.
Natural gas.
Labor.
Sampling.
Equipment maintenance.
TM 1 – BIOSOLIDS TREATMENT COST
FEBRUARY 2025 / FINAL / CAROLLO
WEST COUNTY AGENCY
BIOSOLIDS AND LEACHATE TREATMENT COST OF SERVICE AND MAINTENANCE AGREEMENTS COST ANALYSIS 1-5 Table 1.2 shows the unit cost for these cost categories which were used to estimate the O&M costs.
Table 1.2 O&M Unit Costs
O&M Cost Item Units Cost (2024 dollars)
Electricity(1) $/kWh 0.26
Polymer(2) $/gal 5.00
Natural Gas(3) $/MMBtu 4.00
Labor – Operations(4) $/hr 60.00
Sampling(5) $/sample 50.00
Notes:
gal – gallon; kWh – kilowatt-hour; hr – hour; MMBtu – metric million British thermal units. (1) Unit cost is based on California average industrial customer rate per kWh in July 2024 (https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a). (2) Placeholder to be confirmed/edited by WCA.
(3) Placeholder to be confirmed/edited by WCA. Current value is based on information from United States Energy Information Administration (https://www.eia.gov/naturalgas/weekly/; https://www.eia.gov/todayinenergy/detail.php?id=61644). (4) Placeholder to be confirmed/edited by WCA. Current value is the hourly rate from the WCW Wage Schedule (July 2023 to June 2024) based on Plant Operator/Maintenance Technician. (5) Placeholder until sampling protocol/future monitoring program at WCW WQRRP is determined.
An equipment maintenance cost was also included in the cost model, which was assumed to be 5 percent of the equipment costs. For estimating 20 years of O&M costs, these unit prices were escalated annually by the escalation factors presented in Table 1.3.
Table 1.3 O&M Unit Cost Escalation Factors
O&M Cost Item Units Escalation Factors
Electricity(1) % 10 until 2027; 3
Polymer(2) % 3
Natural Gas(2) % 3
Labor – Operations(3) % 4
Sampling(4) % 3
Equipment Maintenance(2) % 3
Notes:
(1) California electricity rates have been volatile with high escalation rates in the last three years. Recent information suggests continued high escalation rates in the San Francisco Bay Area until 2027 ( https://www.siliconvalley.com/2024/07/24/pge-
electric-gas-bill-consumer-utility-power-economy-south-bay-oakland). T he California annual average (3 percent) escalation from the last 10 years is assumed for the remaining years (https://www.eia.gov/todayinenergy/detail.php?id=63064). (2) Typical escalation factor.
(3) Labor rate escalation has been trending between 4 to 5 percent within the last five years (https://tradingeconomics.com/united-states/wage-growth). (4) Placeholder to be confirmed by WCA.
The unit costs shown in Table 1.2 and the escalation factors in Table 1.3 were used to calculate annual unit costs, as shown in Table 1.6, which were incorporated into the cost model.
TM 1 – BIOSOLIDS TREATMENT COST
FEBRUARY 2025 / FINAL / CAROLLO
WEST COUNTY AGENCY
BIOSOLIDS AND LEACHATE TREATMENT COST OF SERVICE AND MAINTENANCE AGREEMENTS COST ANALYSIS 1-6
1.3.2.2 Cost Model Inputs and Assumptions
The O&M costs were estimated based on the assumptions listed in Table 1.4 and the installed horsepower (hp) for duty units listed in Table 1.5. These assumptions and inputs were used with the unit costs in Table 1.2 to generate the estimated O&M costs.
Table 1.4 Cost Model Inputs/Assumptions for O&M
Cost Model Input Units Value Notes/Reference
Sludge Holding Tanks
Operating hours per day hr/day 24 Assumes sludge holding tank(s) and its ancillary equipment operate continuously.
Operating days per year day/yr 312 Assumes operating schedule is similar to centrifuges and thermal dryer (six days per week per BODR).
Labor – operations hr/day/unit 1 Typical.
Centrifuge Dewatering System
Operating hours per day hr/day 24 Per Section 9.3 of BODR.
Operating days per year day/yr 312 Approximately six days per week per Section 9.3 of BODR.
Labor – operations hr/day/unit 3 Typical.
Thermal Dryer System
Operating hours per day hr/day 24 Assumes thermal dryer system and its ancillary equipment operate continuously.
Operating days per year day/yr 312 Approximately six days per week per Section 11.4 of BODR.
Labor – operations hr/day/unit 3 Typical.
Polymer System (for Centrifuges)
Polymer feed to centrifuge gal/hr 7 Per material balance in Section 9.5 of BODR (stream 23). Emulsion polymer is stored in 300-gal
tote bins per BODR.
Operating hours per day hr/day 24 Assumes same operating schedule as centrifuges.
Operating days per year day/yr 312 Assumes same operating schedule as centrifuges.
Heat Supply for Thermal Dryer
Operating hours per day hr/day 24 Assumes same operating schedule as thermal dryer.
Operating days per year day/yr 312 Assumes same operating schedule as thermal dryer.
Average amount of water evaporated per
day
tons of
water/day
40 Per Section 11.5 of BODR.
Natural gas to dryer scfm 59 Per material balance in BODR (stream 29). Natural gas needed to evaporate water.
Burner air from cogen heat recovery to
dryer
scfm 676 Per material balance in BODR (stream 30). This item will be a credit to WCW for using cogeneration
system.
TM 1 – BIOSOLIDS TREATMENT COST
FEBRUARY 2025 / FINAL / CAROLLO
WEST COUNTY AGENCY
BIOSOLIDS AND LEACHATE TREATMENT COST OF SERVICE AND MAINTENANCE AGREEMENTS COST ANALYSIS 1-7 Cost Model Input Units Value Notes/Reference
Dryer energy requirement (average
conditions)
MMBtu/hr 3.67 Per Section 11.5 of BODR.
Annual average energy requirement MMBtu/yr 27,481 Calculated.
Sampling
Number of shared solids sampling
locations
2 Placeholder until sampling/monitoring program is
developed. Current value assumes sampling of
dewatered solids and dried solids cake.
Number of samples for dewatered solids samples/yr 4 Placeholder until sampling/monitoring program is developed. Current value assumes minimum
quarterly sampling for total suspended solids.
Annual sampling frequency for dried
solids cake
sampling
events/yr
2 Placeholder until sampling/monitoring program is
developed. Current value is minimum sampling
frequency for biosolids compliance per NPDES
permit (R2-2024-0008).
Number of samples for dried solids cake samples/
sampling
event
6 Placeholder until sampling/monitoring program is
developed. Current value is minimum samples for
biosolids monitoring based on Table E-8 of NPDES
permit (R2-2024-0008).
Number of samples per year 16 Placeholder until sampling/monitoring program is developed.
Equipment Maintenance
Equipment cost $ 8,289,782 Placeholder until equipment costs of shared assets are confirmed by WCA. Current value is 50% of total
capital cost for shared WCA assets.
Equipment maintenance percentage % 5 Typical range is 2% to 5%.
Notes:
NPDES – National Pollutant Discharge Elimination System; scfm – standard cubic feet per minute.
Table 1.5 Shared Biosolids Facilities Equipment
Cost Model Input Units Value Reference
Sludge Holding Tanks
Number of Sludge Recirculation Pump 1 (1 duty) Design Drawing 712001-P-105 Sludge Recirculation Pump Motor Size hp 7.5 “WCW Energy Upgrade Equipment List” Centrifuge Dewatering System
Number of Centrifuge Feed Pumps 2 (1 duty, 1 standby) Design Drawing 712001-P-001 Number of Centrifuges 2 (1 duty, 1 standby) Design Drawing 712001-P-001 Number of Centrifuge Discharge Screw
Conveyor System No. 1
1 (1 duty) Design Drawing 712001-P-001
Number of Centrifuge Discharge Screw
Conveyor System No. 2
1 (1 duty) Design Drawing 712001-P-001
Number of Centrifuge Discharge Screw
Conveyor System No. 3
1 (1 duty) Design Drawing 712001-P-001
Centrifuge Feed Pump Motor Size hp 5 “WCW Energy Upgrade Equipment List” TM 1 – BIOSOLIDS TREATMENT COST
FEBRUARY 2025 / FINAL / CAROLLO
WEST COUNTY AGENCY
BIOSOLIDS AND LEACHATE TREATMENT COST OF SERVICE AND MAINTENANCE AGREEMENTS COST ANALYSIS 1-8 Cost Model Input Units Value Reference
Centrifuge Motor Size hp 40 Alfa Laval Project Documentation Transmittal for WCW
Centrifuge Discharge Screw Conveyor
System No. 1 Motor Size
hp 5 Design Drawing 712001-E-703
Centrifuge Discharge Screw Conveyor
System No. 2 Motor Size
hp 15 Design Drawing 712001-E-703
Centrifuge Discharge Screw Conveyor
System No. 3 Motor Size
hp 3 Design Drawing 712001-E-703
Thermal Dryer System
Number of Thermal Dryers 1 Design Drawing 712001-P-002 Gryphon Model 1040 Dryer Power Usage hp 192.1 Section 11.5 of the BODR, Table 11.5-1 Polymer System (for Centrifuges)
Number of Polymer Dilution Feeders 2 (1 duty, 1 standby) Design Drawing 712001-P-106 Polymer Dilution Feeder Motor Size hp 0.5 Velodyne WCW Submittal (Polymer Feeder Information)
The results of the estimated O&M costs calculated based on the cost model inputs and assumptions are included in Table 1.7 and described in the “Model Results” section.
1.3.3 End-Use/Disposal Costs
Cost estimates for the future biosolids management end-use/disposal costs were provided by WCW based on hauling and tipping cost data from October 2023 to September 2024. The cost estimates assumed a 60/40 split between WCW and City of Richmond, respectively, and took into account that the future hauled biosolids will be significantly drier cake compared to most recent years. Based on these cost estimates and assumptions, WCW and the City are responsible for paying approximately $1,125,000 and $790,000, respectively, starting in 2025 and projected to increase 10 percent annually.
1.4 Model Results
Table 1.7 summarizes the estimated capital, O&M, and off-site biosolids management costs for the next 20 years using the cost model inputs listed in Tables 1.1, 1.4, and 1.5 and the unit costs listed in Table 1.6.
Based on these cost estimates, electric power costs constitute the majority of the annual O&M costs.
Since many of the parameters vary year to year, it is recommended that the cost structure between the two parties considers updating the cost model annually for reliable and equitable cost allocation rather than relying on a fixed value for the 20-year estimate.
The cost model is structured such that the main cost factors can be adjusted with flexibility due to updated information. For example, if a specific year requires additional O&M labor hours compared to previous years, the model can be easily updated to reflect this change.
Table 1.8 shows the cost estimates allocated per agency for the next 20 years based on the cost model inputs and assumptions described in this TM.
TM 1 – BIOSOLIDS TREATMENT COST
FEBRUARY 2025 / FINAL / CAROLLO
WEST COUNTY AGENCY
BIOSOLIDS AND LEACHATE TREATMENT COST OF SERVICE AND MAINTENANCE AGREEMENTS COST ANALYSIS 1-9 Table 1.6 O&M Escalated Unit Costs
O&M Cost Item Units 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 Electricity $/kWh $0.26 $0.29 $0.31 $0.32 $0.33 $0.34 $0.35 $0.36 $0.38 $0.39 $0.40 $0.41 $0.42 $0.44 $0.45 $0.46 $0.48 $0.49 $0.50 $0.52 $0.54 Polymer $/gal $5.00 $5.15 $5.30 $5.46 $5.63 $5.80 $5.97 $6.15 $6.33 $6.52 $6.72 $6.92 $7.13 $7.34 $7.56 $7.79 $8.02 $8.26 $8.51 $8.77 $9.03 Natural Gas $/MMBtu $4.00 $4.12 $4.24 $4.37 $4.50 $4.64 $4.78 $4.92 $5.07 $5.22 $5.38 $5.54 $5.70 $5.87 $6.05 $6.23 $6.42 $6.61 $6.81 $7.01 $7.22 Labor – General O&M $/hr $60.00 $62.40 $64.90 $67.49 $70.19 $73.00 $75.92 $78.96 $82.11 $85.40 $88.81 $92.37 $96.06 $99.90 $103.90 $108.06 $112.38 $116.87 $121.55 $126.41 $131.47 Off-Site Disposal $/dry ton $40.00 $41.20 $42.44 $43.71 $45.02 $46.37 $47.76 $49.19 $50.67 $52.19 $53.76 $55.37 $57.03 $58.74 $60.50 $62.32 $64.19 $66.11 $68.10 $70.14 $72.24 Sampling $/sample $51.50 $53.05 $54.64 $56.28 $57.96 $59.70 $61.49 $63.34 $65.24 $67.20 $69.21 $71.29 $73.43 $75.63 $77.90 $80.24 $82.64 $85.12 $87.68 $90.31 $93.01 Table 1.7 Total Cost Estimate Summary
Table 1.8 Agency Cost Allocation
TM 1 – BIOSOLIDS TREATMENT COST
FEBRUARY 2025 / FINAL / CAROLLO
WEST COUNTY AGENCY
BIOSOLIDS AND LEACHATE TREATMENT COST OF SERVICE AND MAINTENANCE AGREEMENTS COST ANALYSIS 1-10
1.5 Analytical Monitoring Program
In addition to the cost estimations for this project, a final consideration for this effort is a recommended enhanced analytical monitoring program to benchmark the sludge quality in (or leaving) the City’s digesters. This is primarily to ensure the absence of, or compliance with limits for toxic components that could otherwise negatively impact biosolids’ on-site treatment and off-site management. Figure 1.2 shows the expected sampling locations and which party would be responsible for each.
Figure 1.2 Recommended Analytical Sampling Locations
It is assumed that the City of Richmond is responsible for sampling the digested Richmond biosolids quality and WCW for the digested WCW biosolids. Sampling the dewatered biosolids and the Class A biosolids is recommended, and the sampling costs for these two solids streams are expected to be shared between the two parties. It is recommended that the two shared sampling locations are monitored for the following parameters:
Flow.
Total solids.
Volatile solids.
Ammonia.
Metals.