Making Wastewater Reclamation More Sustainable

Transcription

1 PAG Environmental Planning Advisory Committee (EPAC) Making Wastewater Reclamation More Sustainable Jackson Jenkins, Director Pima County Regional Wastewater Reclamation Department (RWRD) September 7,

2 Acronyms and Definitions RWRD Regional Wastewater Reclamation Department ROMP Regional Optimization Master Plan WRF Wastewater Reclamation Facility WRC Water Reclamation Campus SWG Southwest Gas Corporation CNG Compressed Natural Gas Bio CNG Compressed Natural Gas produced from biological processes, such as anaerobic digesters or landfills LNG Liquefied Natural Gas FOG Fat, Oil and Grease Anaerobic Digestion is a series of processes in which microorganisms break down biodegradable material in the absence of oxygen and produce biogas ERF Energy Recovery Facility Sludge/Biosolids - Biosolids are the nutrientrich organic materials resulting from the treatment of domestic sewage in a treatment facility Biogas - Refers to a gas produced by the biological breakdown of organic matter in the absence of oxygen Class A Biosolids Class A biosolids contain minute levels of pathogens. To achieve EPA Class A certification, biosolids must undergo extensive treatment processes, which reduce pathogens to below detectable levels Class B Biosolids - Class B biosolids have less stringent EPA standards for treatment and contain small but compliant amounts of bacteria 2 2

3 Raw Sludge Wastewater Sludge as a Resource Multiple Opportunities Sludge Pretreatment FOG or Food Waste Biogas Anaerobic Digesters Biogas Treatment Pipeline Quality Bio-methane (Renewable Natural Gas) CO 2 Special Industrial Use Facility Thermal Needs Vehicle Fuel (CNG, LNG) Green Energy Super Critical CO 2 Digested Sludge Dewatering Side Stream Dewatered Biosolids Nutrients Recovery Algae Farming Agriculture Land Application Soil Amendment Dried Products Combustion Fuel Mine Tailing Reclamation Lipid Extraction 3

4 System-wide Biosolids/Biogas Utilization Master Plan Overview Review existing biosolids management program Acknowledge changes evolving from Regional Optimization Master Plan (ROMP) Biosolids: Evaluations leading to recommendations for long term reliability Biogas: Evaluations leading to recommendations for maximum utilization/benefit 4

5 Current Biosolids Management (Pre ROMP) Anaerobic digestion at both regional facilities, Ina Road WRF and Roger Rd WRF, producing Class B biosolids Digested solids pumped from Roger Rd WRF to Ina Road WRF for dewatering and land application Ina Road WRF Roger Road WRF Avra Valley WRF Mt. Lemmon WRF Randolph Park WRF Green Valley WRF has separate handling and utilization outlet Green Valley WRF Corona de Tucson WRF Raw Sludge Digested Sludge Biosolids Outlet Biosolids Treatment 5

6 Future Biosolids Management (Post ROMP) A new water reclamation campus (WRC) is being built to replace existing Roger Road WRF Partially thickened raw sludge will be pumped from the new facility to Ina Road WRF Green Valley WRF sludge will be wet hauled to Ina Road WRF All the sludge digestion will be consolidated at one location Ina Road WRF Biogas production at Ina will increase significantly Expanded Ina Road WRF New WRC Avra Valley WRF Green Valley WRF Mt. Lemmon WRF Randolph Park WRF Corona de Tucson WRF Raw Sludge Biosolids Outlet Biosolids Treatment 6

7 Biogas Utilization Ina Road energy recovery facility has been in operation since 1970s Provides 2MW power with supplemental natural gas Provides thermal energy required at the plant site Equipment has gone beyond serviceable life High maintenance costs The existing energy generation facility will be decommissioned in the near future More cost effective to provide total energy demand with TEP commercial power 7

8 Key Objectives Defining Master Plan Approach Biosolids Improve long term reliability of biosolids management program Continue beneficial use of biosolids Remain sensitive to ratepayers Prepare for regulatory change and provide public education Biogas Beneficially utilize biogas produced at expanded Ina Road WRF Avoid flaring except for emergency Avoid air permitting complications Maximize economic return to Pima County 8

9 Technology Screening Most Viable Options for PCRWRD World of Options Fatal flaw screening Viable Options Qualitative screening Shortlisted Options Evaluate costs, social, and environmental factors Recommendations 9

10 Beneficially Utilize Biogas after Decommissioning of the Energy Recovery Facility at Ina Road Viable Options: Cogeneration power and heat On-site use of generated power Off-site sale to utility Upgrading/cleaning to pipeline quality and sale Local gas utility Premium markets (beyond Arizona) Direct sale to local industry (via utility pipeline) Use as vehicle fuel (CNG) Local fleets Wheel through pipeline to remote users Biogas used for biosolids drying Use for on-site thermal needs 10

11 Biogas Utilization - Recommendations Recommended Options: Cogeneration power and heat On-site use of generated power Off-site sale to utility Upgrading/cleaning to pipeline quality and sale Local gas utility Premium markets (beyond Arizona) Direct sale to local industry (via utility pipeline) Use as vehicle fuel Local fleets Wheel through pipeline to remote users Biogas used for biosolids drying Use for on-site thermal needs 11

12 Biogas Utilization Action Items Implement biogas upgrading to pipeline quality ( biomethane ) Retain option to use biomethane for plant thermal needs (i.e. boilers) Negotiate with Southwest Gas Corporation (SWG) to accept biomethane into distribution network: Wheeling to users within SWG service area SWG direct purchase Wheeling to nation wide premium market 12

13 Biogas Utilization Action Items, cont. Develop biomethane as vehicle fuel biomethane, i.e. BioCNG PCRWRD fleet Pima County fleet Local Tucson commercial fleets (refuse, buses, product distribution, etc.) Partner with national biomethane distributor Investigate biomethane purchase agreements with Tucson area industries Continue to monitor out-of-state renewable fuel market opportunity to maximize return 13

14 Other Sustainable Opportunities Potential Hydropower Generation at Ina Road WRF Effluent Flow: 35 MGD Effluent Drop at Outfall - 8 feet Produces kw Power App. 8 feet 14

15 Other Sustainable Opportunities, cont. Opinion of Probable Cost: $500,000 to $1,000,000 depending on technology Santa Cruz River Ina Road Head (Vertical Drop): Approx. 12 feet Ina Road WRF Outfall Approx. 400 feet Photo on Right Santa Cruz River Hydraulic Drop Overall Head: 20 feet (Ina Road WRF Outfall to River Bed Downstream of Hydraulic Drop) 15 15

16 Other Sustainable Opportunities, cont. Potential Use of Hydropower Connection to Grid Net Metering Walking / Biking Path Illumination Ina Road WRF Path: 11.2 kw Intermediate Path (Ina-Roger): 18.4 kw Roger Road WRF Path: 16.3 kw Public Park Illumination Six-Field Park: Approx. 180 kw Christopher Columbus Park: Approx. 10kW RWRD Buildings Sub-regional Facilities Building: Approx. 25 kw Overall Path from Ina Road WRF to Roger Road WRF 16

17 Pima County s Sustainability Action Plan Alternative- Fuel Vehicles Carbon Footprint Green Building Water Conservation Resolution Renewable Energy and Conservation Goals Guiding Principles 5-Year Action Plan Waste Reduction Green Purchasing Land Conservation 17

18 Pima County Sustainability Goals Alternative-fuel Vehicles Goals: 100 Vehicles or 25% of Fleet by % of Fleet by 2009; 50% of Fleet by 2017 Renewable Energy & Conservation Goals: 15% Renewable Energy Use by 2025 Methane as Renewable Energy Source Carbon Footprint Reduction Goals: Implement Programs to Reduce County s Carbon Footprint 18

19 PAG Environmental Planning Advisory Committee Top 10 Environmental Issues for 2012 No. Environmental Issues Contribution No. Environmental Issues Contribution 1. Air quality and transportation choices 6. Open space and wildlife corridor preservation 2. Alternative energy and clean fuel 7. Regional wastewater planning and coordination 3. Buffelgrass and control invasive species 8. Regional water 4. Climate change and greenhouse gas emissions 9. Stormwater management 5. Integrated planning to ensure coordination for a sustainable future 10. Sustainability 19 19

20 Questions? Jackson Jenkins, Director - PCRWRD Jackson.Jenkins@wwm.pima.gov 20