Wastewater Facility Plan City of Marshall, Minnesota

Transcription

1 Wastewater Facility Plan City of Marshall, Minnesota Public Hearing March 14, 2017 Bolton & Menk, Inc. Project No. T

2 Glossary of General Terms & Abbreviations MPCA - Minnesota Pollution Control Agency - Minnesota government agency which monitors environmental quality, offers technical and financial assistance and enforces environmental regulations. NPDES permit: National Pollutant Discharge Elimination System. The legal document issued by the MPCA defining how much pollutant a wastewater facility can discharge, sampling and reporting methods, compliance schedules, and other demands. Regulatory Certainty Agreement: Program offered by the MPCA which incentivizes facilities to accept new pollutant limit in exchange for a 20-years freeze on that limit. Useful when a facility believes a limit will be forced upon them near future. PFA: Minnesota Public Facilities Authority Provides municipal financing programs and expertise to help communities build public infrastructure. PSIG: Point Source Implementation Grant Provides grants to local governments to assist with the cost of water infrastructure. Facility Plan: Formal document providing general information on planned infrastructure projects. It is required by MPCA for major wastewater process changes and is also used in funding applications.

3 Glossary of Wastewater Treatment Processes Influent: The raw sewage entering a wastewater treatment facility. Effluent: The treated water leaving a wastewater treatment plant. (primary, intermediate, and final): large tank of still water which allows solid particles to settle and be removed. Trickling filter: Process used to biologically treat wastewater. Aeration tank: Process used to biologically treat wastewater. ATAD: Autothermal Thermophilic Aerobic Digestion Process used to make wastewater sludge safe and palatable for agricultural land application as fertilizer. WAS pump: Waste Activated Pump One of the pumps used in treatment. UV disinfection: Ultraviolet disinfection, a treatment process which eliminates harmful microbes. Anoxic Tank: Biological process which transforms Total Nitrogen into harmless nitrogen gas. Denitrification Filter: Biological process which turns Total Nitrogen into harmless nitrogen gas. MGD: Million gallons per day. Gpd: Gallons per day. GPCD: Gallons per capita per day. Lb(s)/day (ppd): Pounds per day, often used to denote the total quantity of a pollutant.

4 Glossary of Pollutant Terms Abbreviations Total Nitrogen: A pollutant found in all domestic wastewater. It is linked with harmful algal blooms and drinking water contamination. Total Kjeldahl Nitrogen (TKN): Sometimes used as a proxy measurement for Total Nitrogen. NH 3 : Ammonia Nitrogen- A pollutant containing nitrogen that is found in all domestic wastewater. It is linked with harmful algal blooms and is toxic to aquatic life. CBOD 5 : Carbonaceous Biological Oxygen Demand (Five day) Used as a proxy measurement to determine how strong wastewater is. It is also directly related to oxygen depletion, which can suffocate fish. TSS: Total Suspended Solids The concentration of solid particles in wastewater. Phosphorus : A pollutant found in all domestic wastewater. It is linked with harmful algal blooms. ph: A measurement of how acidic water is. Fecal Coliform: A proxy measurement used for the effectiveness of disinfection.

5 Reason for Facility Plan City of Marshall s NPDES Permit is scheduled to be reviewed in It is expected that the City will eventually receive a total-nitrogen limit. The feasibility of pursuing a totalnitrogen Regulatory Certainty Agreement was investigated to lock in limits and take advantage of possible funding opportunities. The possibility of biological phosphorus removal was investigated. Capacity and maintenance needs at the Facility were investigated.

6 City of Marshall Planning Area

7 Population Projections Year City of Marshall Lyon County ,061 24, ,346 25, ,765 25, ,475 24, ,685 25, ,483 25, ,483 25, , , , , , , , , , ,766 2 (1) Based on both historical population trends and County projections (2) Projected by MN State Demographic Center (3) Historic population by MN State Demographic Center

8 Historical Domestic/Commercial Flows Domestic Flow (MGD) Domestic GPCD Minimum Month Average Flow Average Daily Flow (1) Max. Month Average Flow Max. Day Flow (1) Exceeds the recommended 120 GPCD

9 Permitted Industrial Flows (SIU) Flow (MGD) CBOD 5 (lb/day) TSS (lb/day) Phosphorus (lb/day) Archer Daniels Midland 0.8 2,500 5, Turkey Valley Farms 0.7 2,800 1, SSE Manufacturing 0.3 4,500 1,200 60

10 Residential and Commercial Loads Year Population Flow (MGD) CBOD 5 TSS P , ,575 4, , ,020 6, , ,573 5, , ,424 4, , ,643 5, , ,970 5, , ,800 5, , ,228 6, Average 13, ,779 5,348 85

11 Summary of Allocated Design Flows and Loads Parameter Flow (MGD) CBOD5 (lb/day) TSS (lb/day) Phosphorus (lb/day) Archer Daniels Midland (ADM) 0.8 2,500 5, Turkey Valley Farms (TVF) 0.7 2,800 1, SSE Manufacturing 0.3 4,500 1, Non-SIU Sources 1.5 3,300 3, Total Allocated WWTF Capacity ,100 11,

12 Existing and Design Loads Parameter Units Recent ( ) Influent Permit Design Capacity Projected 2037 Design Criteria Design Flow Average Dry Weather Flow (ADW) (MGD) Design Average Flow (MGD) Average Wet Weather Flow (AWW) (MGD) Peak Hourly Flow (PHWW) (MGD) Design Pollutant Loads Carbonaceous Biochemical Oxygen Demand (CBOD5) (lb/day) 7,500 11,972 13,100 Total Suspended Solids (TSS) (lb/day) 10,000 7,844 11,750 Total Kjeldahl Nitrogen (TKN) (lb/day) 1,020 1,614 2,000 Total Phosphorus (lb/day)

13 Existing NPDES Limits Parameter Limit Type Concentration Limit Mass Limit Converted Mass Limit CBOD 5 Monthly Avg. 5 mg/l 85 kg/d lb/d Weekly Avg. 10 mg/l 170 kg/d lb/d TSS NH 3 -N Monthly Avg. 30 mg/l 510 kg/d 1,124 lb/d Weekly Avg. 45 mg/l 765 kg/d 1,687 lb/d Dec-Mar Monthly Avg. 9.4 mg/l kg/d lb/d Apr-May Monthly Avg. 2.4 mg/l 40.8 kg/d 89.9 lb/d Jun-Sep Monthly Avg. 1.1 mg/l 18.7 kg/d 41.2 lb/d Oct-Nov Monthly Avg. 2.3 mg/l 39.1 kg/d 86.2 lb/d Phosphorus (P) 12 month moving total ,973 kg/yr 10,964 lb/yr Chloride (Cl) Monthly Avg. (effective by 2024) 261 mg/l -- kg/d -- lb/d Copper (Cu) Monthly Avg. (effective by 2024) 26 µg/l -- kg/d -- lb/d ph (daily min/max) SU Dissolved Oxygen Monthly Min. 7.5 mg/l Fecal Coliform (Apr-Oct) Monthly Geo Mean 200 #100mL -- --

14 Phase 1 Proposed Work o Capacity upgrades and replacement of aging equipment Phase 2 Primary clarifier sludge pump, WAS pumps, final clarifier pumps Trickling filters and pumping system Aeration tank blowers, diffusers, and aeration controls ATAD expansion New final clarifier New biosolids storage tank o Total nitrogen treatment upgrades, which can be implemented if limits are imposed. Alternative A Anoxic/aerobic tank addition with carbon addition Alternative B Denitrification filter with carbon addition

15 Current Site Plan and Flow Diagram West Trickling Filter East Trickling Filter Mixing Intermediate Filter Pump Station Equalization Basin Sand Filter Aeration Basins Disinfection Cold Plant Shop Pumps and Operations Office Blower Building Final Solids Contact Primary Pretreatment Basin Pretreatment Basin Collection Shop Final Primary Administration Building ATAD Process Thickening Bio-filter Scrubber Screening and Grit Removal

16 Phase 1: Site Plan and Flow Diagram Rehabilitate West Trickling Filter West Trickling Filter East Trickling Filter New Mixing Rehabilitate Intermediate Filter Pump Station Equalization Basin Sand Filter Aeration Basins New Valves and Diffusers Disinfection Cold Converted for ATAD Expansion New Final Final Pumps and Operations Office Solids Contact New Blowers Blower Building Primary New Pumps Equalization Basin Equalization Basin Collection Shop Final Primary Administration Building ATAD Process Thickening Biofilter Scrubber Screening and Grit Removal

17 Phase 2-A: Site Plan and Flow Diagram West Trickling Filter East Trickling Filter Rehabilitate East Trickling Filter Mixing Intermediate New Chemical New Anoxic Tank Aeration Basins Filter Pump Station Equalization Basin Sand Filter Disinfection Cold Final Pumps and Operations Office Blower Building Expanded ATAD Process Final Solids Contact Primary Equalization Basin Equalization Basin Collection Shop Final Primary Administration Building ATAD Process Thickening Biofilter Scrubber Screening and Grit Removal

18 Phase 1 - Projected Capital Costs Item Phase 1 General Facility Upgrades Mobilization $200,000 Site Work/Landscaping $50,000 Site Piping/Valves $50,000 Aeration tank diffusors $200,000 Aeration blowers $250,000 Aeration control infrastructure $150,000 Final clarifier $500,000 WAS pumps $80,000 Primary sludge pump $40,000 Biosolids storage tank $1,500,000 Intermediate clarifier $310,000 Trickling filters $2,000,000 ATAD expansion $1,500,000 Electrical/Controls $750,000 Subtotal $7,580,000 Contingencies (10%) $758,000 Engineering/Administration/Legal (15%) $1,137,000 TOTAL $9,475,000

19 Phase 2 - Projected Capital Costs Item Phase 2 Alternative A Post-Anoxic Zone Phase 2 Alternative B Denitrification Filter Mobilization $600,000 $800,000 Site Work/Landscaping $600,000 $500,000 Site Piping/Valves $300,000 $500,000 Trickling filters $1,000,000 $1,000,000 Anoxic Basin $2,500, Aeration Basins Modification $250, Re-aeration Tanks $300, Chemical and Handling $500,000 $500,000 Intermediate Pump Station- --- $500,000 Denitrification Denitrification Filters Including Building --- $9,500,000 Electrical/Controls $500,000 $750,000 Subtotal $6,550,000 $14,050,000 Contingencies (10%) $655,000 $1,405,000 Engineering/Administration/Legal (15%) $982,500 $2,107,500 TOTAL $8,187,500 $17,562,500

20 Operations Maintenance & Repairs Estimates Item Phase 1 General Facility Equipment Upgrades Phase 2 Alternative A Post-Anoxic Zone Phase 2 Alternative B Denitrification Filter Energy Costs $16,000 $112,000 $237,000 Bio-solids Disposal Costs -- $27,000 $24,000 Chemical Costs -- $1,000,000 $800,000 Professional Services $20,000 $60,000 $60,000 Equipment Replacement $15,000 $50,000 $110,000 Total OM&R Annual Costs $51,000 $1,249,000 $1,231,000

21 Present Worth Analysis Item Phase 1 General Facility Equipment Upgrades Phase 2 Alternative A Post-Anoxic Zone Phase 2 Alternative B Denitrification Filter Capital Total $9,475,000 $8,187,500 $17,562,500 OM & R Annual Costs $51,000 $1,249,000 $1,231,000 OM&R Present Worth (20 Years, 3%) $758,727 $18,581,373 $18,313,587 Total Present Worth Cost $10,233,727 $26,768,873 $35,876,087

22 Project Financing Project will be financed by the Minnesota Public Facilities Authority: Can receive a loan for 20 years at an interest rate of 1.5% to 2.5% Maybe eligible the PISG grant: Currently at 50% of eligible component costs up to $3,000,000 Expected to change to 80% of eligible component costs up to $7,000,000 Other Possible Grants Investigated: EPA State and Tribal Assistance Grants (STAG) Program EPA provides grant money to MN for the PISG grant program Minnesota Department of Employment and Economic Development (DEED) Affordability Grant Money (Rural Development and PFA): For residential users only Residential rates not high enough for current project without the PSIG

23 Potential Impact on User Rates Existing Loan at 1.5% Loan at 2.5% Existing Annual Debt Service $1,929,406 $884,451 1 $884,451 1 Capital Cost -- $9,475,000 $9,475, Year Annualized Capital Cost -- $551,445 $607,348 Annual Operating Cost $4,333,275 $4,384,275 $4,384,275 Total Annualized Costs $6,262,681 $5,820,171 $5,876,074 Note: 1. Debt service adjusted for loans set to expire by 2022.

24 Potential Impact on User Rates Completing Phase 1 & 2A Existing Loan at 1.5% Loan at 1.5% + $7,000,000 Grant Loan at 2.5% + $7,000,000 Grant Existing Annual Debt Service $1,929,406 $884,451 1 $884,451 1 $884,451 1 Capital Cost Phase $9,475,000 $9,475,000 $9,475,000 Capital Cost Phase 2A --- $8,187,500 $8,187,500 $8,187,500 Total Project Cost --- $17,662,500 $17,662,500 $17,662,500 PSIG Grant $7,000,000 $7,000,000 Net Costs --- $17,662,000 $10,662,500 $10,662, Year Annualized Capital Cost --- $1,028,735 $621,045 $683,970 Annual Operating Cost $4,333,275 $5,582,274 $5,582,274 $5,582,274 Total Annualized Costs $6,262,681 $7,495,461 $7,087,770 $7,150,695 Note: 1. Debt service adjusted for loans set to expire by 2022.

25 Residential User Rate Comparison Existing Monthly Rate Phase 1 & 2A (Loan at 1.5%) Monthly Rate Phase 1 & 2A (Loan at 1.5% + Grant) Monthly Rate 5,000 Gal/ Month $41.69 $50.04 $ ,500 Gal/ Month $52.04 $62.47 $ ,000 Gal/ Month $62.39 $74.89 $70.52

26 Project Compliance / Implementation Schedule Item Date Review with City / Finalize Report February 2017 Public Hearing / Council Approval of Facility Plan March 2017 Submit Facility Plan to MPCA March 3, 2017 (no later) Design Period October 2017 February 2018 Bid Project April 2018 Open Bids May 2018 Construction Period June 2018 December 2019

27 QUESTIONS AND COMMENTS