Green Solutions for Municipal Waste The Decentralized Way

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1 Green Solutions for Municipal Waste The Decentralized Way J. Y. Wang, Director, R3C 3 September 2013

2 R3C Residues and Resource Reclamation Centre 2 R3C was established on 1 May 2009 by EDB/EWI/ NTU and was officially launched on 5 Oct The main objective is to conduct cutting edge research and strengthen Singapore s environmental industry s capability in the area of waste resource management. R3C works closely with government agencies and industry R3C acts as an R3 resource and technology transfer centre. R3C provides education and training for R3 professionals.

3 R3C Researchers 3 NEWRI Director A/Prof Wang Jing-Yuan (NTU) Advisors to Director Prof Rainer Stegmann (TUHH) A/Prof (Adj) Cheong Hock Lai Waste to Materials Waste to Energy Contaminated Site Remediation 3 Management + 2 Admin / Lab support + 9 RF + 21 RA + 17 PhD students + 13 Faculty Affiliates (65+)

4 Issues of Current Waste Management The centralized waste management approach is expensive in terms of consumption of water, energy, and infrastructure investment Liquid: activated sludge process (water flushing + aeration + nitrification and de-nitrification + sludge dewatering + ) Solid: collection and transportation (energy consuming) + emissions from incineration and landfilling (land contamination) Subsequent residues disposal (sludge, incineration ash, etc)

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7 The route Five Incineration Plants Since 1979

8 Communities as Renewable Resource Recovery Centers (CRP/NRF)

9 The Decentralized Waste Management Concepts Separation of material streams Separate collection of brown, yellow, and grey water Recovery and reuse of nutrients, purified water, and useful residues (e.g., compost) Minimisation of waste through all those Rs (reduce, reuse, recycle, recover, rethink, repair, restore, remediate, and many other Rs) Conversion of recoverd materials to useful resources Biogas to energy Residues to compost or fertizer Others

10 Utilization of Decentralization-based Waste Management (DWM) Approach Cities or towns short of water supply Cities or towns with limited budget for infrastructure Suburbans or new extenstion areas of big cities New decentralized living and working quarters like Resorts or hotel complexes Military camps, student hostels, training centres Living quarters for Industrial estates Green ecocity development

11 A Decentralised Urban Resource Recovery System

12 Separation of Brown Water, Yellow Water, and Kitchen Waste Separation toilet I + II Kitchen basin Kitchen waste Garbage grinder Sewer system Separation toilet + Storage tank Storage tank Yellow water Storage tank Brown water Storage tank Kitchen waste Wash basin + Garbage grinder

13 No-mix toilet NTU People s acceptance: A logbook is prepared for users comments. Questionnaire will be used for further assessment.

14 R3C position going Forward (Towards Zero Waste) 7 No-mix vacuum toilet development Work together with industrial partners: Design fine-tuning Prototype manufacturing Demonstration construction Test bedding

15 No-Mix Vacuum Toilet Research Activities Completed Diverted urine No-Mix + Vacuum Vacuum evacuation (US Provisional Patent Application No. 61/663,978) Local Characteristics Prototype Lab Demo Technology Disclosure Industrial Partners Next Phase Data Collection and Analysis Trial Sites User Feedbacks Further Improvement Disclosures and Patents Commercialize with Industry Partners Test bedding NTU campus Blk N1 level 2 Test bedding Jurong Lake Park

16 No-mix toilet + Vacuum system Principles: Low water consumption Pressure applied 1L water consumption Penumatic Operated Flush Button Urine by gravity Pipe diameter 32 to 40mm Vacuum Operated Closing Valve Closed system flap valve

17 Storage & Ureolysis Reject supernatant from AD system H2SO4 solution Nutrient Recovery and Odor Removal Tasks & Aims Source- separating urine (low-diluted) Ammonia Stripper Fertilizer: (ammonium sulfate) Local Surveys / Investigations 1. Acceptance of urine-separating toilets; 2. Daily urine production; 3. Dilution rate; 4. Urine collection and preservation; 5. Cross-contamination from feces; 6. Nutrient concentrations in undiluted urine and in tap water (pipe clogging); 7. Urea hydrolysis process and influence factors in tropical area. Reject brine from desalination plants or Seawater as Mg/K sources Heating NH3 depleting urine N-/P-Recovery 1. Sources of additional Mg; 2. Optimization of process design; 3. Liquid-solid separation; 4. Thermodynamics of MKP precipitation; 5. Quality of obtained fertilizers 6. Influence factors: ph, alkaline, etc. 7. Energy cost MAP/MKP Reactor Supernatants (Micro-pollutants Control) Micro-pollutants & Odor Control 1. Heavy metals in struvite precipitation and supernatants & Thermodynamics; 2. Transformation of hormones and pharmaceuticals in urine; 3. Pathogen inactivation process; 4. Biogas, VFAs emission 5. Integrated odor control Drying Fertilizer: Struvite (MAP) K- struvite (MKP) 17 Fig. 1 Process design for nutrient recovery from urine for CRP project

18 Anaerobic Co-digestion of Brown Water and Food Waste 5L Digesters 30L Digesters SBR 2-phase CSTR 2-phase SBR Single stage CSTR Hybrid 5-L digester 30-L digester Two-Phase CSTR SBR Two-Phase SBR Hybrid TS Removal (%) VS Removal (%) Total COD Removal (%) Soluble COD Removal (%) Increase in tvfa levels 5 times - 5 times - Biogas Yield (m 3 /kg VS added )

19 R3C website: 12 Resource Recovery

20 In-vessel Composting Decentralized Community Co-digestion and Co-Composting System

21 A B Gas collector Anode: CH3COO - + 3H2O CO2 + HCO H + + 8e - (-0.29V) Cathode: 2O2 + 8H + + 8e - 4H2O (0.81V) Overall: CH3COO - + 2O2 CO2 + HCO3 - + H2O (1.10V) Cell voltage is positive, implying that electricity can be produced from the MFC. Anode: CH3COO - + 3H2O CO2 + HCO H + + 8e - (-0.29V) Cathode: 8H + + 8e - 4H2 (-0.41V) Overall: CH3COO - + 3H2O CO2 + HCO H2 (-0.12V) Cell voltage is negative and hence electricity needs to be invested to drive the MEC to produce H2. Photographs of typical configurations of two-chamber MFC (A) and MEC (B)

22 Advantages Reduction of water consumption Reduction of wastewater treatment cost Recovery of nutrient/fertilizers Recovery of energy (biogas and electricity) Reduction of energy consumption (waste collection and transportation) Reduction of infrastructure investment cost

23 Summary Decentralization approach is an option to urban sustainable waste management [opportunity] Decentralized urban waste management Separation of different waters (brown, yellow, grey ) and waste Nutrient recovery and odor control Co-digestion of brown water and food waste Co-digestion and co-composting of community waste AD effluent polishing for waste to energy (MEC, fuel cell) Do those Rs around the bin centre of the HDBs Converting communities into resource recovery centers

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25 R3C website: 12 Thank You