Assessing Resource Recovery as a Viable Treatment Alternative

Transcription

1 Assessing Resource Recovery as a Viable Treatment Alternative WERF NTRY1R12 Ron Latimer, P.E Wendell O. Khunjar, PhD Hazen and Sawyer Samuel Jeyanayagam, PhD., P.E, BCEE CH2M HILL

2 The NTRY1R12 project is designed to address challenges associated with resource recovery 2 Characterize factors influencing the adoption of extractive resource recovery systems Provide guidance on the implementation of extractive nutrient recovery technologies at WRRFs Experimentally evaluate extractive nutrient recovery technologies I. State of Science Review II. Database of facilities and technologies performing nutrient recovery III. Market Analysis I. Tool for evaluating resource recovery (TERRY) II. Case Study Guidance documents I. Evaluate high priority extractive P recovery technologies

3 Utility Collaborators 3 Plant # Location Plant Configuration 1 Virginia, USA 2 Washington, USA 3 Wisconsin, USA 4 Saskatoon SK Canada 5 Georgia, USA 6 Idaho, USA Liquid: 5-Stage BNR Solids: Mesophilic Anaerobic Digestion Digested Sludge Dewatering: Centrifuge Liquid: 3-Stage BNR Solids: Mesophilic Anaerobic Digestion Digested Sludge Dewatering: Centrifuge Liquid: 3-Stage BNR and UCT process in parallel Solids: Acid Gas Mesophilic Anaerobic Digestion Digested Sludge Dewatering: Gravity Belt Thickeners Liquid: Modified UCT process Solids: Mesophilic Anaerobic Digestion Digested Sludge Dewatering: Sludge Storage Cells Liquid: 3 and 5 stage BNR + ferric trim on tertiary filters Solids: Mesophilic Anaerobic Digestion Digested Sludge Dewatering: Centrifuge Liquid: MLE, Johannesburg. Conversion to West Bank underway Solids: Mesophilic Anaerobic Digestion Digested Sludge Dewatering: Belt Filter Press? Plants that are operating, commissioning or constructing full-scale struvite recovery facilities

4 Utility Collaborators 4 Plant # Location Plant Configuration 7 North Carolina, USA 8 North Carolina, USA 9 Kansas, USA Calgary AB Canada 12 Florida, USA 13 Florida, USA Liquid: 5 Stage BNR Solids: Mesophilic Anaerobic Digestion Digested Sludge Dewatering: Belt Filter Press Liquid: 5 Stage BNR Solids: Mesophilic Anaerobic Digestion Digested Sludge Dewatering: Belt Filter Press Liquid: 3 Stage BNR Solids: Mesophilic Anaerobic Digestion Digested Sludge Dewatering: Belt Filter Press Liquid: Plant 10: AO process, Plant 11: 3-stage BNR Solids: Mesophilic Anaerobic Digestion Digested Sludge Dewatering: Lagoons Liquid: Pure Oxygen Activated Sludge Solids: Mesophilic Anaerobic Digestion Digested Sludge Dewatering: Centrifuge Liquid: Pure Oxygen Activated Sludge Solids: Mesophilic Anaerobic Digestion Digested Sludge Dewatering: Centrifuge Plants that have performed economic or business case evaluation of full-scale struvite recovery facilities

5 Utility Collaborators 5 Plant # Location Plant Configuration 14 Virginia, USA 15 Texas, USA 16 Texas, USA 17 Ohio, USA 18 Ohio, USA 19 Ohio, USA 20 Colorado, USA Liquid: 4 Stage BNR with Filters Solids: Incineration Thickening dewatering: Centrifuges Liquid: UCT Solids: Sludge Storage followed by Landfill No biological stabilization: Liquid: Modified Ludzack-Ettinger Solids: Anaerobic Digestion Digester Sludge Dewatering: Belt Filter Press Liquid: Conventional activated sludge Solids: Incineration Thickening dewatering: Belt Filter Press Liquid: Conventional activated sludge Solids: Anaerobic digestion (incineration) Thickening dewatering: Centrifuges Liquid: Conventional activated sludge Solids: Acid-gas digestion (incineration) Thickening dewatering: Centrifuges Liquid: Modified Ludzack-Ettinger and A2O Solids: Mesophilic anaerobic digestion (incineration) Thickening dewatering: Centrifuges Plants that have not performed any evaluation but who are interested in full-scale struvite recovery

6 Technology Providers Organization Multiform Harvest, Inc. HaskoningDHV and Procorp Enterprises, LLC Paques bv Ostara Nutrient Recovery Technologies, Inc. Nutrients Recovery Systems CNP-TEC Technology Name Multiform Harvest Crystalactor Phospaq Pearl NuReSys Airprex

7 Other Partners 7 University of Queensland, Australia Commonwealth Scientific and Industrial Research Organization (CSIRO) R. Alexander Associates Inc TU Delft TU Darmstadt Fraunhofer ISI North Carolina State University (NCSU) University of Wisconsin

8 Agenda for Presentation 8 Review of NTRY1R12 Key Findings Technology Review Market Analyses Case Studies Overview of Experimental Phase Review of Deliverable/Resources Open Forum

9 Lack of regulations, knowledge and budget impede implementation 9 Drivers for Adopting Nutrient Recovery Non-renewable supply of fertilizer feedstocks Barriers against Adopting Nutrient Recovery Lack of knowledge about technical options Rising energy consumption and costs Limited capital budget Technology development Desire for low cost, sustainable nutrient management option Potential to minimize O&M issues Extractive Nutrient Recovery Long payback periods Lack of regulatory drivers Lack of acceptance by stakeholders Potential to stabilize nutrient removal performance Staffing constraints

10 Challenges revolve around technical, economic and regulatory limitations 10 Technical Technologies are unknown entities. Insufficient time and staff to review technologies Insufficient data to evaluate technology performance Insufficient experience in operating technology Unknown maintenance requirements and long-term operational viability Economic Insufficient and/or competing needs for funds Unknowns regarding cost of implementation, operating costs, etc. Uncertainty with respect to future demand for fertilizer product. Competition for product if many utilities adopt the technology. Lack of regulatory drivers i.e., no effluent nutrient limits. Regulatory Lack of public acceptance

11 Challenges revolve around technical, economic and regulatory limitations 11 Technical Technologies are unknown entities. Insufficient time and staff to review technologies Insufficient data to evaluate technology performance Insufficient experience in operating technology Unknown maintenance requirements and long-term operational viability Economic Insufficient and/or competing needs for funds Unknowns regarding cost of implementation, operating costs, etc. Uncertainty with respect to future demand for fertilizer product. Competition for product if many utilities adopt the technology Lack of regulatory drivers i.e., no effluent nutrient limits. Regulatory Lack of public acceptance

12 Addressing Technical Considerations

13 From a technological perspective, a three step framework may be appropriate 13 Dilute wastestream Accumulation Release Extraction Recovered chemical nutrient product Low nutrient effluent Accumulation step to increase nutrient content N > 1000 mg N/L and P > 100 mg P/L Release step to generate low flow and high nutrient stream Extraction step produces high nutrient content product

14 There are multiple options for each step of extractive recovery 14 Accumulation Release Extraction Enhanced biological phosphorus removal (EBPR) Algae Purple non-sulfur bacteria Adsorption/Ion exchange Chemical precipitation NF/RO Anaerobic digestion Aerobic digestion Thermolysis WAS release Sonication Microwave Chemical extraction Chemical crystallization Electrodialysis Gas permeable membrane and absorption Gas stripping Solvent extraction Not all systems require all three components Can optimize each option separately Can also stage implementation

15 Consider a common scenario in which enhanced biological phosphorus removal is applied 15 Nutrient recovery (% recovery efficiency) N P K Product (% wt nutrient) Accumulation EBPR - (15-50%) - Sludge (5-7% P) Release Anaerobic digestion Biosolids Extraction Crystallization (> 90%) Mg-Struvite (12% P, 5% N), K-struvite, Fe or Ca phosphate

16 Intentional struvite recovery helps minimize nuisance struvite formation and reduce P recycle 16 FBR Effluent 80-90% P removal 15-30% N removal Dewatering Dryer Struvite MgNH 4 PO 4 6 H 2 O Magnesium Caustic Sand (Procorp) Centrate/Filtrate High NH3-N and PO4-P Fluidized bed reactor or CSTR used for struvite recovery High quality, slow release fertilizer revenue offsets costs Reduction in ferric/alum payback on capital

17 There are several commercial options for struvite recovery 17 Name of Technology Pearl Multiform Harvest NuReSys Phospaq Crystalactor Airprex Type of reactor upflow fluidized bed upflow fluidized bed CSTR CSTR with diffused air upflow fluidized bed CSTR with diffused air Name of product recovered Crystal Green struvite fertilizer BioStru Struvite fertilizer Struvite, Calcium phosphate, Magnesium phosphate Struvite fertilizer % Efficiency of recovery from sidestream 80-90% P 10-40% NH3-N 80-90% P 10-40% NH3-N >85% P 5-20% N 80% P 10-40% NH3-N 85-95% P for struvite 10-40% NH3-N > 90% P for calcium phosphate 80-90% P 10-40% NH3-N # of full-scale installations

18 What about if we use chemical precipitation for mainstream P removal? 18 Accumulation Release Chemical (Precipitation) Anaerobic digestion Nutrient recovery (% recovery efficiency) N P K (> 90 %) Product (% wt nutrient) Commercial process - Sludge Non-proprietary - Biosolids Non-proprietary Release via Anaerobic digestion solubilizes N and P Need additional strategy/technology to release and extract metal complexed P

19 There are options to allow us to recover nutrients from ash/sludge 19 Name of Process Seaborne Krepro SEPHOS BioCon PASH PHOXNAN Product recovered struvite; diammonium sulfate (DAS) iron phosphate as a fertilizer aluminum phoshate or calcium phosphate (advanced SEPHOS) phosphoric acid struvite or calcium phosphate phosphoric acid Process feedstock sludge sludge sewage sludge ash sewage sludge ash sewage sludge ash sludge

20 There are options to allow us to recover nutrients from ash/sludge 20 Extraction/recovery can involve acidification, thermolysis, chemical extraction and chemical precipitation Post-processing to remove heavy metals may also be required Few full-scale installations are present Regulatory mandate for recycling P is needed to drive implementation of these technologies

21 Our Technology Matrix Summarizes Nutrient Recovery State of Science 21

22 Advances in nutrient recovery will require both sustaining and disruptive innovation 22 Accumulation Release Recovery Enhanced biological phosphorus removal (EBPR) Anaerobic digestion Crystallization Adsorption/Ion exchange Thermolysis WAS release Gas stripping Purple non-sulfur bacteria Algae Membrane filtration Solvent extraction Chemical extraction Sonication Microwave Electrodialysis Gas permeable membrane and absorption Solvent extraction

23 Addressing Regulatory Considerations

24 Nutrient recovery is another strategy for removing P from WRRF Urine 67% P mass balance in WRRF 24 Effluent 10% Feces 33% Primary Sludge 10-15% Secondary Sludge 25-40% EBPR or Chem - P Removal 35-50% From Cornel et al. (2009) Sludge Up to 90% Liquid treatment regulatory limits not absolute requirement for driving project

25 Quantifying other benefits (cost and non-cost) can help make the case for nutrient recovery 25 Struvite recovery can: Provide factor of safety associated with Bio-P Minimizes impact of sidestream return Reduce energy and chemical consumption Offsets due to reduction in aeration and supplemental carbon Reduction in sludge quantity and hauling costs Minimize nuisance struvite formation and reduce O&M costs Reduce or increase the P content of biosolids If land application P index limited, removing P in the form of struvite will shift N:P ratio If more P is appreciated, selectively precipitating P into biosolids will increase biosolids P content Improve sludge dewaterability Result in higher sludge cake %TS Reduce polymer demand

26 Addressing Economic Considerations

27 Recovery of a high demand chemical nutrient product is the goal 27 Approximately 85% of all nutrient products used in developed countries is related to agriculture Focus on producing products for the agricultural sector For use in agricultural sector, recovered chemical nutrient products must: 1. Have consistent nutrient composition and uniform distribution 2. Have no/minimal odors 3. Have no/minimal pathogen content 4. Have desirable physical characteristics

28 There are multiple products for consideration 28 Common Name Chemical Formula Product Form Uses Magnesium Struvite NH4MgPO4 6H2O Solid Agricultural and ornamental crop fertilizer. Hydroxyapatite (Ca5(PO4)3(OH) Solid Agricultural and ornamental crop fertilizer. Sorbent for heavy metal contained in flue gas. Ornamental crop fertilizer. Vivianite Fe3(PO4)2 8H2O Solid Inexpensive blue pigment for arts ~US$312 to 429/metric tonne N and products crafts. Agricultural and ornamental crop ~US$550 to 628/metric tonne of fertilizer. P product Phosphoric acid H3PO4 Liquid Removal of rust, de-scaling of boilers and heat exchange tubes. Agricultural and ornamental crop Ammonium nitrate NH4NO3 Liquid or Solid fertilizer. Oxidizing agent in explosives. Ammonium sulfate (NH4)2SO4 Liquid or Solid Agricultural and ornamental crop fertilizer. Used in flame retardant materials.

29 Demand (million metric tonne) Region specific needs also play a role in the overall demand for recovered nutrient products 29 Overall national fertilizer demand has been relatively steady over the past 10 yrs If we look a little deeper Increased demand Decreased demand Total N Demand Total P2O5 Demand Total K2O Demand Demand in specific regions has fluctuated see WERF report for more details on region specific demand data

30 The specialty agriculture and ornamental markets are receptive to WRRF products ,000 metric tonne P 2 O 5 / year, 110,000 metric tonne TN/year WWT industry can potentially meet these demands (optimistic projections) Between 30 and 100% of the specialty and ornamental P 2 O 5 fertilizer demand (as struvite) Between 30 and 194% of the specialty and ornamental N fertilizer demand (as ammonium sulfate solution) Consider specialty and ornamental fertilizer demand ranges from 1-5 % of total agricultural demand Need to develop niche, higher value markets for green recycled product decrease payback

31 Potential Market Entry Points for Recovered Products 31 Fertilizer Producer (e.g., WRRF) Wholesaler Broker or importer Dealer Network Product mayblended and/or bagged End User (e.g., farmer, blender and baggers) Multiple points of entry into the secondary market Most TPs facilitate interaction with the market Facility has the choice of entering the market directly

32 Objective 2 Provide guidance on the implementation of resource recovery technologies at WWTP

33 Case studies of full-scale facilities also developed 33 Developed case studies in 3 categories Category 1 facilities that are currently operating or constructing struvite harvesting 6 facilities Category 2 facilities that have performed desktop analyses and/or pilot 7 facilities Category 3 facilities that have no performed any detailed economic analyses but who may have operated a pilot 7 facilities Each case study describes: Nutrient limits, Plant configuration, Challenges faced, Drivers for nutrient recovery, Economics associated with struvite harvesting, lessons learned where applicable

34 Case studies of full-scale facilities also developed 34 Each case study describes: Nutrient limits, Plant configuration, Challenges faced, Drivers for nutrient recovery, Economics associated with struvite harvesting, Lessons learned where applicable

35 Flowsheet has been developed to aid decision making process 35 No Does the WRRF experience nuisance struvite formation? No Are land application regulations guided by soil P index? No Are there effluent TP limits at the WRRF? Yes Yes Yes Is biological P removal practiced (intentionally or unintentionally)? Is Chemical P practiced? Yes Yes No Yes Is Anaerobic digestion practiced? No No Struvite recovery from sidestreams will not be favorable P recovery via struvite harvesting should be evaluated WAS P release step prior to anaerobic digestion can increase the amount of P available for recovery Magnesium and ammonium (aerobic digestion) will be required for struvite harvesting Is Aerobic digestion practiced? No Is thermochemical stabilization practiced? No WAS P Release step should be considered to release Poly-P in systems performing Bio-P Biological stabilization will be required to release remainder of P Magnesium and ammonium will be required for struvite harvesting if biological stabilization is not performed Yes Consider recovery from ash/sludge e.g, KREPRO, SEABORNE, ASHDEC, MEPHREC, Sephos, Biocon, PASH,

36 Tool for Evaluating Resource RecoverY developed to facilitate preliminary evaluation 36 Compare struvite crystallization with precipitation with coagulant (i.e., alum or ferric) Different scenarios evaluated in current version Known sidestream characteristics Unknown sidestream characteristics; Anaerobic digestion Unknown sidestream characteristics; Anaerobic digestion & imported sludge Unknown sidestream characteristics; Aerobic digestion Unknown sidestream characteristics; Aerobic digestion & imported sludge Unknown sidestream characteristics; No stabilization

37 Cost benefit analyses model takes into account non-financial criteria 37

38 TERRY output allows you to estimate capital, O&M and rank alternatives based on non-cost critieria 37

39 TERRY status and implications 38 User manual and tutorial under development Beta-testing with numerous facilities Who do we envision using this tool? Utility managers, research and development personnel Consultants Regulators Future applications Incorporate regulatory, economic and technical constraints Estimate the value of benefits that can not be quantified currently. E.g. Environmental benefits

40 Objective 3 - Experimentally evaluate nutrient (focus on P) recovery technologies

41 Two projects underway 41 Project 1 - Optimize phosphorus release and availability during and after anaerobic digestion Goal is to increase productivity of struvite recovery systems Project 2 Examine the benefits of P, N and K recovery via electrodialysis and its influence on sludge dewatering Goal is to achieve simultaneous recovery of P, N, K and improve sludge dewaterability in Bio-P applications

42 Two projects underway 42 Project 1 - Optimize phosphorus release and availability during and after anaerobic digestion Goal is to increase productivity of struvite recovery systems Project 2 Examine the benefits of P, N and K recovery via electrodialysis and its influence on sludge dewatering Goal is to achieve simultaneous recovery of P, N, K and improve sludge dewaterability in Bio-P applications

43 Enhancing recovery potential with existing technology Urine 67% P mass balance in WWTP 43 Effluent 10% Feces 33% Primary Sludge 10-15% Secondary Sludge 25-40% EBPR or Chem - P Removal 35-50% From Cornel et al. (2009) Sludge Up to 90% % P from influent Accumulation via EBPR Up to 90 Release via Anaerobic Digestion Up to 60 Recovery via crystallization Up to 50

44 Project 1 examined use of low ph during anaerobic digestion to increase P solubilization 41 Depressed ph < 7.0 Batch reactor Low ph increased solubility of P Tradeoff is reduction of methane production Suitability for acid-phase digester

45 Project 1 examined use of low ph during anaerobic digestion to increase P solubilization 45 Continuous flow experiments confirm batch testing result Increased P availability Reduced methane production

46 Project 1 examined use of chelating agents/ion exchange additives to increase P solubilization 43 P released (mg P/g of additives) Digested Sludge (ph 8.2) Synthetic Wastewater (ph 7.5) EDTA Trisodium citrate Zeolite Lewatit Monoplus Purolite S Purolite S Amberlite DOWEX Control Preliminary economic analysis Value of 1 kg of struvite = $0.33/kg Cost to produce 1kg of struvite with chemical addition EDTA addition = $13.40/kg struvite Citrate addition = $6.89/kg struvite PuroliteS930= $15.97/kg struvite To become economical, need to offset between 16 and 40% of the dewatering operating costs Assuming polymer cost of $2.00/lb and 20 lb/dry ton polymer dose

47 Next steps include 47 Address economics of ph adjustment CO2, other additions Capital and O&M requirements Integrate into payback analyses for struvite harvesting Address economics of chelator/resin addition Capital and O&M requirements Integrate into payback analyses for struvite harvesting

48 Project 2 looks at applicability of using electrodialysis for resource recovery and improving sludge dewaterability 45 Treated sidestream Domestic wastewater Bio-P Sludge Thickening Electrodialysis Dewatering Anaerobic Digestion

49 Objective 2 experimental plan 46 Test 5 different K concentrations on SBR and sludge dewatering performance, using sewage wastewater Mimics benefits of electrodialysis Sludge dewatering test: Capillary Suction Timer (CST) Thermo-gravimetric technique Extracellular polymeric substances (EPS) analysis Diluted sludge volume index (DSVI) Benchmark electrodialysis performance with centrate Address economics of electrodialysis Capital and O&M requirements Quantify benefits where possible

50 Preliminary results from SBR testing 50 K + = 20 mg/l K + = 200 mg/l Effluent NO3-N (mg/l) 3.4 ± ± 1.0 Effluent PO4-P (mg/l) 4.5 ± ± 1.0 Effluent K + (mg/l) 17.7 ± ± 3.2 Thickened Sludge VS (mg/kg) 1.2 ± ± 0.1 TS (mg/kg) 1.6 ± ± 0.1 CST (sec) 44 ± ± 14.0 DSVI (ml/g) 0.32 ± ± 0.1 Thermogra ± ± 2.4 Digested Sludge VS (mg/kg) TS (mg/kg) CST (sec) DSVI (ml/g) Underway EPS data Thermogra..

51 Project Status and Schedule

52 Project Schedule 52 Deliverable Date Status Report 1 State of Science Review and Excel Database Technology Matrix 30-Nov-12 Submitted Workshop 1 WEF/IWA Nutrient Removal and Recovery Workshop July Jul-13 Completed Workshop 2 WEFTEC October Oct-13 Completed Report 2 Summary of Workshop from WEF/IWA Nutrient Removal and Recovery Workshop July 2013 and WEFTEC Nov-13 Submitted Report 3 Standalone Case Study Documents 28-Feb-14 Submitted Report 4 Interim research results from Objectives 3.1 and 3.2 and summary of WEFTEC 2014 workshop 30-Jun-14 Submitted Tool for Evaluating Resource Recovery (TERRY) 1-Jun-14 In preparation Online tutorial for TERRY 1-Jun-14 In preparation Trade Article 1-Jun-14 In preparation Workshop 3 WEFTEC 2014 October, 2014 Completed Peer Reviewed Journal Article 30-Dec-13 Completed Draft Final Report (Report 5) 30-Dec-14 In preparation Final Report 1-Mar-15 In preparation