The Quest for Energy Independence

Transcription

1 The Quest for Energy Independence City of Fort Worth Village Creek Water Reclamation Facility Biosolids and Odor and Corrosion Conference and Expo July San Marcos, Texas Sebastian Buster Fichera, REM

2 Sustainability: Perpetual Motion in Nature The use and reuse of matter Taking what nature provides, changing it to meet our needs, then putting it back to be used again.

3 Service to over 900,000 customers in 23 communities Rated capacity MGD Average daily flow MGD Average annual biosolids produced - 30,641 dry tons Reuse Water Biosolids Energy

4 Potential Energy from Biosolids MG Anaerobic Digesters Average Gas Production scfm at 38% VSS destruction Potential Gas Production at 75% VSS destruction 1,170-1,900 scfm

5 Keep it mixed up Pressure wave mixing Replaced lance gas bubblers 7 foot diameter disk Keeping Solids in suspension Average 28% grit volume 18 inch displacement

6 8% methane gas Increase due to cleaning and linear mixers 51% methane gas Increase Co-Digestion Start-up

7 2 5.2 MW Turbine Generators Installed 2000 Provides 45% electrical demand $0.062/kWh Gas Consumption scfm

8 Transfer of Energy Nutrients Land Application Irrigation Bacteria Plants Heat Exhaust Animals & Humans Electricity Biosolids Water Methane Waste Waste Treatment

9 Pre-Turbines Post Turbines 45% Demand 22% Demand

10 The Village Creek Perpetual Motion Machine Nutrients Land Application Irrigation Bacteria Plants Heat Exhaust Animals & Humans Electricity Steam Biosolids Water Methane Air Waste Waste Treatment

11 Heat Recovery Steam Generator Recovers 950 o F waste heat from turbine Produces steam at 235 psi Duct burner gas consumption scfm 1,300 o F after Duct burner scfm Gas Gap Total gas demand 2,350 2,700 scfm

12 Steam Turbines to complete the Cycle 2 Steam drive turbines 2 31,000 scfm blowers Replace h.p. electric blowers at 1.8MW/day

13 Average Gas Production scfm at 38% VSS destruction Potential Gas Production at 75% VSS destruction 1,170-1,900 scfm Leonard Ripley, PhD, P.E. Freese and Nichols 1 MG co-digestion: CH 4 yield = 3,940 SCF/hr Energy yield = 3.8 MM BTU/hr Leonard Ripley, PhD, P.E. Freese and Nichols Purchase more Landfill Gas Solids pretreatment Improve Dig. Eff. Co-digestion

14

15 Profile developed to assess waste for: Strength (COD/gas production potential) Loading on the digesters Pollutants that threaten digester performance or sludge quality (i.e. heavy metals, sanitizers, sulfates) Compatibility with other waste streams Solids content: pumpable (at varying temperatures), not diluting digester; limited storage Non-volatile fraction (cost to treat/dispose of residuals)

16 Accountability, key contact info Contract period Fees Indemnification/liability Sufficient waste to meet gas production needs (and to meet our obligation under our ESPC) Delivery mechanisms and time frames (customers arrange for delivery at their expense and at prescribed schedule)

17 Build off existing Pretreatment Wastehauler fee structure approved by City Council Continuing gathering data to refine Consideration what the market will bear (significant costs to potential customers associated with transportation) Exempt fees when gas-production potential offsets costs for handling and provides substantial benefit

18 8% methane gas Increase due to cleaning 51% methane gas Increase Co-Digestion Start-up

19 81% methane gas Increase Co-Digestion March 2013

20 94% methane gas Increase Co-Digestion June 2013

21 4, , Biosolids Production June June 2013 Cleanout of Ponds 3, , Dry Tons 2, , , Digester s 9, 10,11,12, 13,14 clean out, linear mixer installation and evaluation 0.00

22 Pre-Turbines Post Turbines $0.062 kwh $0.041 kwh HRSG 45% Demand 61% Demand

23 Conclusions Biosolids = Energy Management of biosolids is essential for maximum benefit. Processes required to enhance biosolids breakdown on the front end. Plans to expand from 6 Co-digestion digesters to 14. Goal is to be putting power on the grid by the end of Energy is all around us.you have to be creative to find it and use it

24