Perspectives on Wastewater as a Resource

Transcription

1 May 23, 2012 Perspectives on Wastewater as a Resource PWO Seminar Doing More with Less Denver MWRD Art Umble, PhD, PE, BCEE Americas Wastewater Practice Leader

2 Outline What is Water Quality Trading? The New Paradigm The Factory Drivers for Water Quality Trading Need for Resource Recovery Elements of a Water Quality Trading Program Is there a Case for Resource Recovery Case Study: Wabash River Watershed Is There a Low Hanging Fruit? Summary The Factory of Tomorrow 2

3 Yesterday s Disposal Plant Tomorrow s Resource Recovery Factory Raw Wastewater Preliminary Solids & Resource Recovery ENERGY FACTORY Biosolids Handling & Market Resources 7.2 million tons of biosolids/yr 115 trillion BTUs ~ 33.4 billion KW-hr Tertiary NUTRIENT FACTORY Disinfection Primary WATER FACTORY Secondary U.S. DOE estimates that bioenergy could displace one third of the current demand for petroleum fuels nationwide by the mid 21st century. (U.S. DOE, 2005). Advanced Outfall Receiving Water Body 3

4 Water Recovery Should be First Priority % GR % Gap Municipal / Domestic Industry Agriculture Billion m Ground Water 2000 Surface Water Today 2030 Basins w/ Deficits Source: 2030 Water Resources Group; Global Water Supply and Demand Model, 2009 Basins w/ Surplus Existing, accessible reliable, sustainable global supply 4

5 Water Recovery Should be First Priority *Does not include any potential impacts due to global climate change 20% - historical improvements in water productivity 60% - remaining gap Billion m Existing, accessible, reliable, sustainable global supply 20% - Increase in supply under the business-as-usual scenario 3000 Who s competing for available supplies? What s the quality needed? 0 Today 2030 Source: 2030 Water Resources Group; Global Water Supply and Demand Model,

6 Water Recovery Should be First Priority Increase in Annual Water Demand Billion m 3 China India Sub-Saharan Africa Rest of Asia N America Europe S America MENA Oceania $ billions Stacklin, (2011) World Water Resource Recovery Opportunity Source: 2030 Water Resources Group,

7 The Energy Opportunity Energy in raw waste water Currently consume about 21 billion kw-hr/yr in US $1.5 billion in energy cost 10X more than Required Energy Recovery Opportunity Adapted from: Shizas & Bagley (2004) 7

8 MW-hr/yr Anaerobic Digestion is Key Process to Energy Recovery Net-zero Net Positive Advanced Energy Technology Enhanced Pretreatment Process Efficiencies On-line Automated Controls Sidestream Pre-digestion Advanced Anaerobic Digestion Efficient CHP Based on ~7 MGD CAS WWTP 8

9 Value Proposition is in the Biogas and How It s Used $/GJ Adapted from: Parry, 2005 Assumptions: Electricity 0.07 $/kwh, Natural Gas 7.2 $/GJ, CHP 35% elec. eff., 40% thermal eff., Gasoline 1.0 $/L 1 GJ ~ 1 MBTU $ billions Energy Source Energy Value 0 Stacklin, (BTU) 2011 Flare Boiler Elec Gen 1 NG pound of CHP dry biosolids Vehicle 6,000 9,000 1 kw-hr of electricity Fuel 3,412 Energy Source 1 cubic foot of natural gas 1,028 1 cubic foot of untreated biogas 1 cord of wood 20 million Energy Value (BTU) 1 pound of dry biosolids 6,000 9,000 1 kw-hr of electricity 3,412 1 cubic foot of natural gas 1,028 World Energy Recovery Opportunity 1 cubic foot of untreated biogas cord of wood 20 million Biosolids + Digester Gas

10 Decision Roadmap to Energy Recovery is Complex Inside Plant Outside Plant Defining the Biosolids Value Chain Conventional Anaerobic Digestion Flare CHP Co-Digestion FOG/HOS LEGEND FOG = Fats, Oils & Grease HOS = High Organic strength Waste MP-M = multi phased, mesophilic AP-M = acid phased, mesophilic MS T/M = multi-staged, thermo-meso MS M/T = multi-staged, meso-thermo 2 = key decision point = activities inside fence = activities outside fence Sludge Minimization Class B 4 Cell Lysis Biogas Utilization Technology Solar Waste Heat MP-M / AP-M 5 Gas Cleaning Enhanced CHP Sludge Drying Waste Heat Pelletizing Biosolids Technology 6 MS T/M MS M/T Natural Gas Incineration Bio-fuels P-Recovery Net Metering Maintain Existing Thermal Hydrolysis Central Composting Renewable Energy & Credits Class A Reuse Class B Reuse Ash Markets Revenue Markets Class B Land Application Class A Biosolids Beneficial Reuse 10

11 222 Million people Why Does Progress Seem Slow? Small percentage of WWTPs have anaerobic digestion Very small percentage generate power Excessive pay-back on Investment Still relatively easy to permit sites for land application Difficult to compete against cheap fossil fuel power No. of WWTPs With AD With CHP 11

12 Is there a Case for Resource Recovery? It s Multi-Nexus Energy Source Higher Quality Nutrients Reuse 12

13 Technology The Case for Nutrient Recovery: Removal or Recovery? 30/30 TN: 8-10 TN: 8 TP: 1 Performance Requirement TN: 6 TP: 0.5 TN:3 TP: 0.1 TN: 3 TP: 0.04 TN: 2 TP: <0.05 Level CAS MLE Source: Bratby and Jimenez, 2011 UCT 5-S BDNP HRC + Denit Filters Denit Filters + HRC + Tertiary Filters HRC + Denit Filters + Partial MF/RO TN: 1 TP: <0.05 Denit Filters + MF/RO 13

14 The Case for Nutrient Recovery: Economics of Removal Preliminary Primary Secondary WAS to DAFT UV LEVEL 1 14

15 The Case for Nutrient Recovery: Economics of Removal Preliminary Primary MLE WAS to DAFT UV LEVEL 2 15

16 The Case for Nutrient Recovery: Economics of Removal Preliminary Primary UCT Fermentate Sidestream RAS WAS to DAFT UV Deep Bed Filtration LEVEL 3 16

17 The Case for Nutrient Recovery: Economics of Removal MeOH Preliminary Primary 5-S BNDP MUCT Fermentate Sidestream RAS WAS to DAFT UV Deep Bed Filtration LEVEL 4 17

18 The Case for Nutrient Recovery: Economics of Removal MeOH Preliminary Primary 5-S BNDP MUCT Fermentate Sidestream RAS WAS to DAFT UV Denit Filtration MeOH HRC Coagulation Flocculation LEVEL 5 Chemical Sludge Dewatering 18

19 The Case for Nutrient Recovery: Economics of Removal MeOH Preliminary Primary 5-S BNDP MUCT Fermentate Sidestream RAS WAS to DAFT UV Tertiary Filtration HRC Coagulation Flocculation Denit Filtration MeOH LEVEL 6 Chemical Sludge Dewatering 19

20 The Case for Nutrient Recovery: Economics of Removal MeOH Preliminary Primary 5-S BNDP MUCT Fermentate Sidestream RAS WAS to DAFT UV Denit Filtration MeOH HRC Coagulation Flocculation LEVEL 7 Chemical Sludge Dewatering RO MF Reject 20

21 The Case for Nutrient Recovery: Economics of Removal MeOH Preliminary Primary 5-S BNDP MUCT Fermentate Sidestream RAS WAS to DAFT UV RO MF Denit Filtration MeOH EQ Reject LEVEL 8 21

22 The Case for Nutrient Recovery: Economics of Removal Capital Costs Operational Costs $/gal/day $/MG Treated Process Technology Source: Bratby and Jimenez,

23 Nexus: Stricter Standards More Energy? Nitrogen Removal Energy Demand 2000 kw-hr/mg treated Phosphorus Energy Demand Phosphorus Removal Energy Demand 0 CAS OxD w/ N MLE A2O 4-S Brdph Process Configuration Step Feed kw-hr/mg treated Pt Chem CAS AO AO w/ Ferm A2O 5-S Brdph Process Configuration Kang, et al./usepa,

24 Sidestream : Low Hanging Fruit to Resource Recovery Grit Primary Biological FC Tertiary PS Thkng WAS Thkng Anaerobic Digester Dewatering Liquid Characteristics Parameter Conc., (mg/l) TSS BOD Sludge Digestion DS Dwtg Solids Disposal NH3-N PO4-P Centrate Trtmt 24

25 Sidestream : Low Hanging Fruit to Resource Recovery Sidestreams: liquid residues from digested sludge dewatering operations (~1% of total ADF) Sidestream (biological and/or phys/chem) Tight BNR/ENR Requirements Reduce ammonia nitrogen load to main process train 15-35% of influent nitrogen load Reduce and/or equalize total nitrogen load to main process train Reduce phosphorus load to main process train 5-35% of influent phosphorus load Augment Nitrifier Biomass in Main Process Train Reduce Energy Consumption Reduce External Carbon Supplementation 25

26 Energy Savings/Recovery Sidestream InNITRI BAR (CaaRB) BABE SHARON MAUREEN CANON OLAND DEMON Autotrophic Aerobic Environment 75% of O 2 Req t 25% of O 2 Req t 1 mol Nitrite (NO 2- ) 1 mol Ammonia (NH 3, NH4 + ) 1 mol Nitrate (NO 3- ) 1 mol Nitrite (NO 2- ) Nitrification and Denitrification 40% of Carbon Req t Heterotrophic Anoxic Environment 60% of Carbon Req t 1/2 mol Nitrogen Gas (N 2 ) Source: Stinson, B., WERF

27 Nitrifier Growth Dynamics Key Role in Resource Recovery Process Technology Temperature Affect Typical Municipal Raw Wastewater Typical Dewatering Liquors Relative Growth Dynamics AOB NOB NOB > AOB No NO2 Accumulation AOB controls design AOB > NOB NO2 Accumulation NOB controls design 25 o C T 27

28 Nitrifier Growth Dynamics Dissolved Oxygen Affect NOB Sidestream Design Mainstream Nitrification Design Degree of Nitrifier Inhibition AOB No Inhibition NOB Inhibition > AOB Inhibition NO2 Accumulation DO 28

29 Heat Exchanger On the Road to Resource Recovery: Example: SHARON Process Stable High Activity Reactor Over Nitrite Carbon NaOH NH3-N-laden Influent 35 o C NH4 NO2 N2 NO2 25% of O 2 Req t 1 mol Nitrate (NO 3- ) 40% of Carbon Req t Control ph Control DO Control Temp 75% of O 2 Req t 1 mol Nitrite (NO 2- ) 1 mol Ammonia (NH 3, NH4 + ) Autotrophic Anaerobic Environment 1 mol Nitrite (NO 2- ) 60% of Carbon Req t 1/2 mol Nitrogen Gas (N 2 ) 29

30 On the Road to Resource Recovery: Example: Anammox ANaerobic AMMonia OXidation NH NO 2 - N 2 + 2H 2 O 25% of O 2 Req t 1 mol Nitrate (NO 3- ) 40% of Carbon Req t Energy savings Supplemental Carbon elimination 75% of O 2 Req t 1 mol Nitrite (NO 2- ) 1 mol Ammonia (NH 3, NH4 + ) Holy Grail 1 mol Nitrite (NO 2- ) 60% of Carbon Req t 1/2 mol Nitrogen Gas (N 2 ) Source: Melcer

31 Is there a Value Proposition in Nutrient Recovery Today? World Nutrient Recovery Opportunity $ billions Stacklin, USA Europe Asia Oceania Africa Latin Am 31

32 Ammonia Recovery Process (ARP) Ammonia Stripper / Absorber NH 3 in water H 2 SO 4 Air Stripping Column Scrubbing Column Air (NH 4 ) 2 SO 4 liquid ammonium fertilizer 32

33 Process for Ammonia Recovery Integrated Stripper/Scrubber Marketed by: 3XR 33

34 Ammonia Recovery Process (ARP) Castion/Thermal Energy Corp (controlled air separation technology CAST) Evaporator Ion Exchange process using ZnSO 4 & H 2 SO 4 Product = (NH 4 ) 2 SO 4 crystals Packed Bed Scrubber Concentrator Source: Thermal Energy Corporation (2011) 34

35 Processes for Phosphorus Recovery Phosnix Ostara Ostara (MAP) Multiform Harvest (MAP) DHV Crystalactor (CaP) PHOSNIX (MAP) WASStrip Struvite Crystals: Slow-Release Fertilizer 35

36 Processes for Phosphorus Recovery Absorbents: granular activated alumina Zirconium oxide, iron oxide hydrated iron oxide layered double hydroxides fly ash steel slag Absorbent Column Effluent Recovery Tank To Downstream Processes P Recovery Concentrated Influent Preliminary Chemical Regeneration Ion Exchange: anionic resins phosphate selective polymerics Recycle Source: Reardon and Machado,

37 Energy Resource Recovery: What about UASBs? UASBs seem to be getting the most attention High SRT (<40 days) in relation to HRT COD reduction efficiency between 60%-80% for loadings in the range of 0.4 to 3.0 kg COD/m 3 /d BOD reduction efficiency generally about 5% - 8% higher than COD May not meet the effluent standards for discharge UASB anaerobic downflow filter aerobic downflow filter UASB Reactor Anaerobic Aerobic > 90% COD Removal Source: Ghangrekar, M. Kahalekar, U., IE(I) Journal EN (2003) 37

38 Resource Recovery: What about Fuel Cells? Influent PC Bioreactor Tertiary Effluent WAS PS MFC WAS Anaerobic Digestion Biogas Wind / Solar Green Energy PAFC Waste Heat Individual Fuel Cell Energy to All Processes Source: Karatt, V.J. (2010) Microbial Fuel Cell microbially mediated combustion 38

39 Resource Recovery: What about Algal Biofuels? High Rate Reactors Influent Biosolids Municipal Wastewater Light CO 2 Rapid Algal Production Final Effluent Pond Reactors Photobioreactor Biosolids Processes Residuals Nutrients Recycles Harvested Algae 1. Fats / Sugars release & separation; 2. Evap Solvents; 3. Convert fats to biodiesel Combustible Biodiesel fuel Fuel Energy Density, MJ/L Ethanol 19.6 Butanol 29.2 Gasoline 32.0 Diesel 38.6 Biodiesel Source: Schideman, L.; Agriculture & Biological Engineering, U. of Illinois; Bioenergy Seminar (2010) Lundquist, T.; CalPoly State U. 39

40 Resource Recovery: What about Bioplastics? Influent PC Bioreactor FC Final PS RAS Fermenter VFA1 WAS VFA2 PHA Culture To Extraction Process Seed Enriched Strain Source: USEPA Grant National Center for Environmental Research, (2008) Liu, H.Y. (2008) 40

41 Resource Recovery Factory of Tomorrow Biological Physical/Chemical Degritted Fine Screened Wastewater w/ Screenings Washing Aerobic MBR SRT 1-2 d Reactive Filtration System P-removal RO System N/TDS Removal Final Effluent for Reuse Thickened Waste Solids Solubilization of Organics Filter Backwash Solids/Liquid Separation Concentrate for N-Recovery Solids Pretreatment Digester Return Excess Solids Biogas Production and Utilization Waste Solids for Additional P-Recovery Source: Sutton, et al., 2009 High-Performance Anaerobic Digester/MBR System 41

42 Technology Development Introduction to Market Market Acceptance Technology Has a Life Cycle Technology Introduction Technology Growth Technology Maturity PROVEN Technology!! ~ Decade 42

43 Summary Facilities are Resource Factories There is value proposition in Resource Recovery Anaerobic Digestion is a Key to Net Zero Energy Economic Value is in the Utilization of the Biogas Resource Recovery means a MULTI-NEXUS Low Hanging Fruit is Sidestream Nutrient Recovery Technologies are Emerging Tomorrow s Plant will Look Much Different 43