Sustainable Biosolids Management Direct Energy Use Does Not
Sustainable Biosolids Management: Direct Energy Use Does Not Tell All Ruth Borgmann, Hazen and Sawyer Erika Bailey, City of Raleigh TJ Lynch, City of Raleigh Stephanie Ishii, Hazen and Sawyer Amy Hanna, Hazen and Sawyer
Agenda for our time together Background GHG Evaluation Approach Results and Hotspot Analysis
Background
Neuse River Resource Recovery Facility Raleigh, NC Advanced BNR Process Current capacity 60/75 MGD Biosolids Management: Converting to THP and Advanced Anaerobic Digestion with conversion of biogas to RNG
Biosolids Outlets Current: Class B Liquid Onsite Offsite Composting Raleigh Plus Landfill Bioenergy: Class A Cake Land Application
Project Drivers Aging biosolids handling infrastructure Plan for future capacity needs Uncertainty of future Class B land application Sustainable solution for the future
Climate/Energy Action Plan City-wide interdepartmental effort Goals: • • Operational efficiency Energy reduction GHG reduction Cost savings Over 100 strategies were evaluated for implementation Bioenergy Recovery Project Completed in 2012; currently being updated Practical implementation of strategies to minimize carbon-related emissions, maximize energy efficiency of existing City facilities and provide renewable energy opportunities.
Greenhouse Gas Emissions
Why not just look at direct energy use? 5 4, 5 4 3, 5 MW 3 2, 5 2 1, 5 1 0, 5 0 Current Bioenergy Direct energy use doesn’t account for digester gas to beneficial use As a net energy producer the bioenergy project qualified for CWSRF Green Project Reserve Funding
GHG Evaluation Approach
GHG Evaluation: Alternatives Dewatering Lime Stabilization PS Class A Alkaline Raleigh Plus Mc. Gill Composting OR Landfill WAS Current Uncovered Aerobic Digesters Covered Aerobic Digesters Gravity Belt Thickening Class B Liquid Land App. - Onsite - Offsite Bioenergy FOG PS Blend/ Screen WAS Thickening THP Pre. Dewatering Final Dewatering Anaerobi c Digestion Class A Land App.
GHG Evaluation: Approach Inventory Value GHG Equivalent Operational Phase Functional Unit: 1 lb(dry) pre-processed biosolids CO 2 Equivalents GHG Footprint
GHG Evaluation: Approach Functional Unit: 1 lb (dry) pre-processed biosolids Inventory Value GHG Equivalent k. Wh Functional Unit OR lb. product Functional Unit lb. CO 2 e k. Wh OR lb. CO 2 e lb. product GHG Footprint lb. CO 2 e Functional Unit
GHG Evaluation: Inventory Units: k. Wh/Functional Unit or gal Alum/Functional Unit Inventory Value Inventory Items • Electricity • Chemicals • Biosolids transportation • Offsets GHG Equivalent GHG Footprint
Inventory – Current Dewatering Lime Stabilization PS Class A Alkaline Raleigh Plus Mc. Gill Composting OR Landfill WAS Uncovered Aerobic Digesters Gravity Belt Thickening Covered Aerobic Digesters Class B Liquid Land App. - Onsite - Offsite Functional Unit: 1 lb (dry) pre-processed biosolids
Inventory – Current Electricity Lime Stabilization Dewatering PS Class A Alkaline Raleigh Plus Mc. Gill Composting OR Landfill WAS Uncovered Aerobic Digesters Gravity Belt Thickening Air Electricity Covered Aerobic Digesters Class B Liquid Land App. - Onsite - Offsite CAD Mixing, Air & Odor Control Functional Unit: 1 lb (dry) pre-processed biosolids
Inventory – Current Chemical Polymer Electricity LKD Dewatering Lime Stabilization PS Class A Alkaline Raleigh Plus Mc. Gill Composting OR Landfill WAS Uncovered Aerobic Digesters Air Gravity Belt Thickening Electricity Polymer Covered Aerobic Digesters Class B Liquid Land App. - Onsite - Offsite CAD Mixing, Air & Odor Control Functional Unit: 1 lb (dry) pre-processed biosolids
Inventory – Current Offsets Polymer Electricity LKD N&P Offsets Dewatering Lime Stabilization Class A Alkaline Raleigh Plus PS Mc. Gill Composting OR Landfill WAS Uncovered Aerobic Digesters Air Gravity Belt Thickening Electricity Polymer Covered Aerobic Digesters CAD Mixing, Air & Odor Control Class B Liquid Land App. - Onsite - Offsite N&P Offsets Functional Unit: 1 lb (dry) pre-processed biosolids
Inventory – Current Transport Polymer Electricity LKD N&P Offsets Dewatering Lime Stabilization Class A Alkaline Raleigh Plus PS Mc. Gill Composting OR Landfill WAS Uncovered Aerobic Digesters Air Gravity Belt Thickening Electricity Polymer Covered Aerobic Digesters CAD Mixing, Air & Odor Control Class B Liquid Land App. - Onsite - Offsite N&P Offsets Transport Functional Unit: 1 lb (dry) pre-processed biosolids
Inventory – Bioenergy CNG Buses WAS Steam Boiler Thickening Gas Cleaning Flare PS Blend/ Screen Pre. Dewatering FOG THP Anaerobi c Digestion Final Dewatering Class A Land App. Alum Sidestream Functional Unit: 1 lb (dry) pre-processed biosolids
Inventory – Bioenergy WAS Steam Boiler Thickening Electricity CNG Buses Gas Cleaning Flare PS Blend/ Screen Pre. Dewatering FOG THP Anaerobi c Digestion Final Dewatering Class A Land App. Alum Sidestream Functional Unit: 1 lb (dry) pre-processed biosolids
Inventory – Bioenergy WAS Steam Boiler Thickening Natural Gas CNG Buses Gas Cleaning Flare PS Blend/ Screen Pre. Dewatering FOG THP Anaerobi c Digestion Final Dewatering Class A Land App. Alum Sidestream Building Heat Functional Unit: 1 lb (dry) pre-processed biosolids
Inventory – Bioenergy WAS Steam Boiler Thickening Chemical CNG Buses Gas Cleaning Flare PS Blend/ Screen Pre. Dewatering FOG THP Anaerobi c Digestion Final Dewatering Class A Land App. Alum Sidestream Building Heat Functional Unit: 1 lb (dry) pre-processed biosolids
Inventory – Bioenergy WAS Steam Boiler Thickening Offsets CNG Buses Gas Cleaning Flare PS Blend/ Screen Pre. Dewatering FOG THP Anaerobi c Digestion Final Dewatering Class A Land App. Alum Sidestream Building Heat Functional Unit: 1 lb (dry) pre-processed biosolids
Inventory – Bioenergy WAS Steam Boiler Thickening Transport CNG Buses Gas Cleaning Flare PS Blend/ Screen Pre. Dewatering FOG THP Anaerobi c Digestion Final Dewatering Class A Land App. Alum Sidestream Building Heat Functional Unit: 1 lb (dry) pre-processed biosolids
Inventory – Bioenergy WAS Steam Boiler Thickening CNG Buses Gas Cleaning Flare PS Blend/ Screen Pre. Dewatering FOG THP Anaerobi c Digestion Final Dewatering Class A Land App. Alum Sidestream Building Heat Functional Unit: 1 lb (dry) pre-processed biosolids
GHG Evaluation: Equivalent Units: lb. CO 2 e / k. Wh or lb. CO 2 e / gal Alum Inventory Value • • GHG Equivalent GHG Footprint Electricity • City of Raleigh GHG Inventory Report approach (EPA references) Biosolids transportation • City of Raleigh GHG Inventory Report approach (EPA tools, MOVES 2014 a) Chemicals • Literature review Offsets • Literature review
GHG Evaluation: Footprint Units: lb. CO 2 e / Functional Unit Inventory Value GHG Equivalent GHG Footprint • Editable Excel Workbook • Option for default and/or user defined values for inventory items and GHG equivalents • References / explanations for default values • Dynamic figures • Total GHG comparison across alternatives • GHG hotspot analysis within alternatives
Results and Hotspot Analysis
GHG Footprint lb. CO 2 e / lb (dry) pre-processed biosolids 0, 10 0, 00 0. 06 Current Bioenergy -0, 10 -0, 20 -0, 30 -0, 40 -0, 50 -0, 60 -0. 55
GHG Footprint – Without Offsets lb. CO 2 e / lb (dry) pre-processed biosolids 0, 60 0, 40 0, 20 0. 06 0. 45 0. 18 0, 00 -0, 20 -0, 40 -0. 55 -0, 60 Current Bioenergy
GHG Footprint – With Offsets lb. CO 2 e / lb (dry) pre-processed biosolids 0, 60 0, 40 0, 20 0. 06 0. 45 0. 18 -0. 12 0. 06 0, 00 -0, 20 -0, 40 -1. 00 -0. 55 -0, 60 Current Bioenergy -0. 55
Current vs. Bioenergy GHG Production -15 000 -20 000 -25 000 -30 000 Current Bioenergy 2035 2030 2035 100 000 50 000 0 -50 000 -100 000 -150 000 -200 000 -250 000 -300 000 -350 000 -400 000 2020 -10 000 2030 -5 000 2025 tons CO 2 e/year 0 2020 5 000 2025 Cumulative GHG Production Annual GHG Production Current Bioenergy is able to convert digester gas to RNG which allows for GHG Footprint to decrease with increasing flow to Neuse River RRF Typical Passenger Car is estimated to emit 5. 5 tons CO 2 e per year
Hotspot Analysis – Current Phosphorus fertilizer offset 0, 2000 Transport 0, 1500 Nitrogen fertilizer offset Landfill Transport Offsite Class B (GFI) Transport Chemical 0, 1000 Offsite Class B (COR) Transport Onsite Class B Transport Class A Mc. Gill Transport 0, 0500 Electricity Class A Raleigh Plus Transport LKD Polymer - BFP and DCEN 0, 0000 Current Polymer - GBT Electricity - Dewatering, DCEN -0, 0500 Offsets Electricity - Dewatering, BFP Electricity - CAD Odor Control -0, 1000 Electricity - CAD Air Electricity - CAD Mixing -0, 1500 Electricity - GBT Electricity - UCAD Air
Hotspot Analysis – Current Phosphorus fertilizer offset 0, 2000 Transport 0, 1500 Lime Nitrogen fertilizer offset Landfill Transport Offsite Class B (GFI) Transport Chemical 0, 1000 Offsite Class B (COR) Transport Onsite Class B Transport Class A Mc. Gill Transport 0, 0500 CAD Air & Mix Electricity Class A Raleigh Plus Transport LKD Polymer - BFP and DCEN 0, 0000 Current -0, 0500 N Offset -0, 1000 P Offset Polymer - GBT Electricity - Dewatering, DCEN Offsets Electricity - Dewatering, BFP Electricity - CAD Odor Control Electricity - CAD Air Electricity - CAD Mixing -0, 1500 Electricity - GBT Electricity - UCAD Air
Hotspot Analysis – Bioenergy Transport Chemical Electricity Offsets
Hotspot Analysis – Bioenergy Transport Chemical Electricity Diesel Offset (Buses) N Offset P Offsets
Effect of Varying FOG Quantities - Bioenergy Diesel Offset (Buses) Footprint: -0. 55 lb CO 2 e/Functional Unit FOG Receiving – 30, 000 gpd Footprint: -0. 50 lb CO 2 e/ Functional Unit FOG Receiving – 0 gpd
How does this help CORPUD? Internal decision making Further operational adjustments for hotspot reduction Communication with stakeholders and public about environmental stewardship
Thank you from the team for your attention Contact Information: Ruth Borgmann, PE rborgmann@hazenandsawyer. com
BULLPEN
Effect of Varying Biosolids Outlets – Current Original Scenario Updated Scenario Raleigh Plus: 20% Raleigh Plus: 0% Composting: 20% Composting: 50% Onsite Class B: 4% Onsite Class B: 0% Offsite Class B: 9% Offsite Class B: 0% Landfill: 47% Landfill: 50%
Effect of Varying Biosolids Outlets – Current 0, 2000 0, 1500 0, 1000 0, 0500 LKD CAD Air & Mix 0, 0000 0, 1000 Electricity - UCAD Air Electricity - GBT Electricity - CAD Mixing Electricity - Dewatering, DCEN Polymer - BFP and DCEN Class A Mc. Gill Transport Onsite Class B Transport 0, 0500 0, 0000 Current -0, 0500 N Offset -0, 0500 -0, 1000 P Offset -0, 1000 -0, 1500 Footprint: 0. 06 lb CO 2 e/Functional Unit -0, 1500 Footprint: -0. 01 lb CO 2 e/ Functional Unit
Sustainability and efficiency is a core focus of the City of Raleigh’s strategic plan Objective 3: Optimize public infrastructure projects to address community resiliency, sustainability and efficiency. Development of a bioenergy recovery program for the Neuse River Resource Recovery Facility is a key deliverable under this initiative.
GHG Footprint - Current 0, 2000 0, 1800 Functional Unit: 0. 182 1 lb (dry) biosolids lb CO 2 e / Functional Unit 0, 1600 Offsets: 0, 1400 • Nitrogen Fertilizer 0, 1200 • Phosphorus Fertilizer 0, 1000 0, 0800 0, 0600 0, 0400 0, 0200 0, 0000 -0. 120 0. 062 Biosolids Outlets: • Raleigh Plus • Composting • Class B Onsite • Class B Offsite • Landfill
GHG Footprint - Bioenergy Functional Unit: 0, 600 0. 45 1 lb (dry) biosolids + FOG blend 0, 400 Offsets: lb CO 2 e / Functional Unit 0, 200 • Diesel • Nitrogen Fertilizer • Phosphorus Fertilizer 0, 000 -0, 200 -0, 400 -0, 600 -0, 800 -1. 00 -0. 55
EPA GHG Analysis Approaches
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