Grandville CWP Electrical Generation What s possible? Todd Wibright, Superintendent, City of Grandville CWP

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1 Grandville CWP Electrical Generation What s possible? Todd Wibright, Superintendent, City of Grandville CWP

2 Grandville CWP Egg Shaped Anaerobic Digester and Bio-Gas Cogeneration What we did How it works Outcomes

3 Egg shaped Anaerobic Digester (ESD) Solids Handling Footprint Cost (life cycle) Cleaning Efficiency Potential for Future Class A Biosolids

4 Biogas System Components

5 Why Biogas Cleaning? Biogas Impurities Moisture H2S Siloxanes

6 Dual Fuel Engine Driven Generator POWER 280 kw Biogas 360 kw Nat Gas Cogeneration System HEAT MMBTU/hr thermal (at 280 kw) Overall Efficiency = 86% using both heat and power!

7 Heat

8 Integrated Energy Management System ESD Biogas Supply ESD Heat Demand CHP Biogas Demand CHP Heat Supply CHP Power Supply Lab/Ops Heat Demand Blowers and other equipment Power Demand (IEMS)

9 Biogas Production Biogas Quantities Currently producing ~120,000 cuft/day ESD is more efficient than anticipated! Over 70,000 cuft/day to cogen Remainder to boiler or flared off. (opportunity)

10 Estimated Savings Energy Savings Projected $95,000/yr at startup rates Currently over $110,000/yr savings Natural Gas Savings (heat) Projected $47,000/yr at startup rates Hard to measure due to multiple gas meters, but estimated $43,000/yr savings.(less due to drop in gas pricing) Payback Will be less than 6 years for cogen equipment!

11 Before and After

12 Where are we at today? Consistently utilizing kW of power Providing all heat necessary for Digester and Lab/Ops Building Balancing Sludge Feed Rates to Optimize Gas Production Reviewing options to make use of excess gas produced.

13 Questions? Todd Wibright City of Grandville CWP (616) Brian Hannon, P.E. Moore & Bruggink, Inc. (616)

14 FLINT S COGENERATION EXPERIENCE ROBERT CASE CITY OF FLINT WATER POLLUTION CONTROL SUPERVISOR

15 Flint s Solids Handling, 2008

16 PUBLIC PRIVATE PARTNERSHIP 2008 CONSTRUCTION CONTRACT 2013 REVISED OPERATIONS BASE FEE Began with Governor s 2008 Trade Mission Center of Energy Excellence with Kettering University Energy Production and Cost Savings Major Goals MEDC Grant + SBI Funding = Capital Improvements Processing Cost Savings Provides Operating Revenue

17 FLINT BIOGAS PLANT - PHASE I Sludge from Treatment Plant Ex. North Digester Gas Holde r Digestat e Storage Bioga s To Boiler Digested Biosolids to Incinerator Existing Biosolids Incinerator 08/09/2010 Ground breaking 05/16/2011 Seed sludge loading 08/2011 Thru 09/2011 Production startup Cost savings begins

18 GAS QUANTITY/QUALITY CONCERNS GAS HANDLING SYSTEM DESIGN Flow Rates Pressure/Vacuum Relief Valves Flare Gas storage Water separation BIOGAS QUALITY Changes in energy content Increases in Hydrogen Sulfide Dilution of siloxanes (mg/m 3 ) Higher chemical (Carbon/F 3 Cl 2 ) costs

19 STEP BY STEP: The New Order I Landfilling to replace incineration Use biogas to generate lower electricity costs II Enhance biogas production pursue outside wastes Blend high energy outside wastes with dilute municipal sludge III Digest the blended wastes Produce electricity with internal combustion engine generator

20 Now we can run the generator at its capacity! Increased revenue - Tip fees, power generation Increased gas production BENEFITS OF BLENDED WASTES Potentially higher degradation of solids Micro- Biological diversity From 40 MCF per day To over 75 MCF?

21 BIOWORKS ENERGY ROLE AND OBJECTIVES Procure High Energy Wastes Oversee Blending and Digestion Process Produce Maximum Energy: Biogas and Electricity Business and Revenue Expansion

22 DIFFERENT WASTES, SYNERGISTIC EFFECTS MUNICIPAL WWTP SLUDGE (PRIMARY, WAS, TWAS) 1 to 8% total solids 60 to 90 % Volatile Solids Biogas is 55 to 65% Methane Heterogeneous MIX Good for Digestion Relatively Low Energy Density Contains both MACRO/Micro Nutrients required for stable process EXTERNAL SUBSTRATES (FOOD PROCESSING WASTES, ORGANIC PROCESS, ETC) TS% - Large Variations, Rheology Not Directly Related to TS% 30 to 100% Volatile Solids Biogas is 45 to 75% Methane Homogeneous Mix Can Be Difficult to Digest as a Mono-Culture Higher Energy Densities Than WWTP Sludge May Lack Macro/Micro Nutrients Proper Combination of the Two - Better Than Either Component

23 SUBSTRATES: A Different Kind Of Business MANAGEMENT Not always as advertised! Marketing and procurement of contracts & permits Pricing Issues - Critical Educate planners/administrators of the benefit potential CHALLENGES RISKS Unpredictable Quantity & Quality Long term contracts Hard to come by Educating stakeholders regarding the entire process Permits Must be Right-Size for efficient processing Under utilization of capital improvements if substrates don t materialize Laboratory QA/QC of Substrates Insure material is as planned

24 PROCESS CONCERNS SUBSTRATE VARIABILITY The Unknown and Sometimes Unwanted Impacts IMPACTS Thickening and dewatering performance may vary RESPONSIBLI TY Owner must insure compatibility with digestion system and NPDES limits TESTING Substrates should be tested prior to system injection, before problems arise SUBSTRATE PROVIDER Not responsible for the WWTP. Responsible only to get rid of their waste reliably. QUANTIFY Recycle Streams and nutrient Loads

25 LEARNING TO HANDLE BLENDED WASTES Proportions of the desired mix and how to control it Higher gas production than expected Rapid Rise Underestimated gas production + insufficient Mixing = rapid expansion in gas/liquid matrix Flaring of gas instead of power generation = lost revenue

26 ACCOMPLISHMENTS INCREASED VOLUME OF EXTERNAL SUBSTRATES INSTALLED ELECTRICAL POWER GENERATION CONSTRUCTED BIOSOLIDS LOADING FACILITY DECOMMISSIONED INCINERATION

27 Municipal Biosolids Flint Solids Handling, 2016 Receiving Pit High Strength Wastes

28 Piston engine - most efficient running at full capacity Can Produce 200 kw of Power from 75 MCF per day of biogas Produces enough heat to keep digester at 95⁰

29 ADVANTAGES OF COMBINING ORGANIC SUBSTRATES WITH MUNICIPAL BIOSOLIDS Greatly increased gas production Increased revenue Tipping fees Diversion of high strength wastes Improved utilization of assets

30 High Energy Content Low Residual Quantity Desirable Substrate Qualities Easily Mixed & Handled High Organic Content

31 SUBSTRATE EXAMPLES Cafeteria Wastes Animal Origin Grease & Fats Food Processing Wastes Spoiled & Excess Food Production

32 BRIGHT FUTURE FOR BLENDED WASTES More Municipal Wastewater Plants Accepting More economical and efficient disposal of more wastes Wastewater Plants can effectively handle both the solid and liquid waste components End product can be processed further to make compost or land applied Better use of Limited Resources Resource Recovery Additional Green Energy Production Efficient power production No distribution expense

33 QUESTIONS?

34 City of Midland Combined Gas to Energy System January 16, 2014

35 City of Midland Combined Gas to Energy System Landfill Gas Collection In 2007, staff took the initial steps toward Active Gas Collection The endeavor provides three major benefits to the City: 1. Reduction of fugitive gas/odor leaving the property, resulting in improved air quality in the community 2. Fuel source for electricity generation 3. Compliance with MDEQ regulations well in advance of being required to install a gas collection system

36 N 66.5 acres

37 City of Midland Combined Gas to Energy System Landfill Gas Composition As degradable refuse decomposes, it produces landfill gas (LFG): 53% Methane (CH 4 ) 47% Carbon Dioxide (CO 2 ) Trace Components Present (greenhouse gases)

38 City of Midland Combined Gas to Energy System 38 Biological Methane Potential (BMP) 1 ton of MSW produces 3,000 cubic feet (cf) of methane Bioreactors accelerate the process (Special permit to add Biosolids to LF) (Recirculation of Leachate) LFG can be processed in economically feasible quantities

39 City of Midland Combined Gas to Energy System Funding Opportunity In spring 2009, the American Recovery and Reinvestment Act (ARRA) provided additional funding to Michigan s State Revolving Fund Program (SRF) for Shovel Ready Projects. The availability of the low-interest funds with principal forgiveness put the Combined Gas to Energy System (GTE) on a fast track, it was considered a Shovel Ready Project!

40 City of Midland Combined Gas to Energy System Funding Opportunity The major components to construct the GTE were: Active Gas Collection System (Landfill site) Gas Pipeline (3 mile) Gas to Energy Facility (adjacent to WWTP) Goals Achieve a 20 year payback 60% ARRA funds 40% SRF funds

41 City of Midland Combined Gas to Energy System Key Project Attributes Utilize Both Digester Gas from POTW and LFG from City s Landfill Maximize Electrical Energy and Heat Recovery from the Facility Rehabbed Existing Pipeline to Combine Gas Sources (old Dow brine pipeline) Power Plant Located at WWTP Electric Power Sold to Dow Net Metering WWTP, GTE & WTP City Utilizing Waste Heat

42 City of Midland Combined Gas to Energy System Project Included Two Major Sites Compressor Building Mixed Municipal Solid Waste Landfill Engine Generating Plant Wastewater Treatment Facility (Nearly 3 Miles Away) Total Project cost $11.3 Million

43 City of Midland Combined Gas to Energy System 43 Project Costs Gas Collection / Control $2,104,000

44 City of Midland Combined Gas to Energy System Two 200 HP Single Screw Compressors

45 City of Midland Combined Gas to Energy System Single Screw Compressor Basis of Design LFG is Compressed and Chilled to Drop Out Moisture Prior to Conveyance Through a Three Mile Pipeline to the Engine Generator Building

46 City of Midland Combined Gas to Energy System 46 Project Costs Gas Pipeline, 3 miles $ 910,000

47 City of Midland Combined Gas to Energy System Compression System at Digester Gas system includes two 0.5MG Primary Mesophilic Digesters and a 1MG floating lid Secondary Digester. Digester Compressor Skid can produce a maximum of 65 CFM

48 City of Midland Combined Gas to Energy System Gas to Energy Facility LFG and Digester Gas is Comingled at the Power Plant Site and Contains Approximately 56% Methane

49 City of Midland Combined Gas to Energy System Building Exterior Matched WWTP Face Brick Matched Adjacent Wastewater and Water Treatment Plant Structures

50 City of Midland Combined Gas to Energy System 3520C Unit Produces1.6 MWs/Each Purchase Power Agreement (PPA) Negotiated with Dow Chemical Green Power is Exported Through a Switchyard to Consumers Power Through Local Substation

51 City of Midland Combined Gas to Energy System WWTF Substation Facilitates Interconnect Power is Sent to Combined WWTP and GTE Facility Switchyard/Substation

52 City of Midland Combined Gas to Energy System Generator Room at GTE Building

53 City of Midland Combined Gas to Energy System Heat Recovery Components Exhaust- Heat Recovery Silencer, With Bypass Exhaust Silencer Coolant- Heat Exchanger and Thermostatic Regulator Valve

54 City of Midland Combined Gas to Energy System Recovered Heat Benefits Plant Efficiency is Increased with CHP Heat Recovery Used for: Digesters Heat at WWTP Hot water/showers Second Gen. start-up Class A Biosolids? Heat at Water Plant?

55 City of Midland Combined Gas to Energy System Electricity Metering Agreement Dow Purchases Green Energy up to 1.0 MkWh per month WWTP, GTE and WTP net meter power usage up to 1.0 MkWh Energy produced above 1.0 MkWh is paid at Market Rate Current 13 month production average is 1.1 MkWh WWTP and WTP billed at 1.03 MkWh for Aug. 2016

56 City of Midland Combined Gas to Energy System August 2016 Actual (producers only) 20% Landfill and 80% Compressors Gas to Energy System used WWTP WWTP Collections system Total system used (minus WTP) 86,400 kwh 56,200 kwh 190,600 kwh 90,700 kwh 423,900 kwh Gas to Energy System Produced 1,155,460 kwh

57 Questions?