WASTE TO ENERGY DISTRIBUTED GENERATION FROM FOOD WASTE IN HONG KONG

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1 WASTE TO ENERGY DISTRIBUTED GENERATION FROM FOOD WASTE IN HONG KONG Ir Dr. Anthony MA Principal Consultant Environmental Management Division Hong Kong Productivity Council 1

2 Climate Action Plan in Hong Kong Under the Paris Agreement, Hong Kong government needs to review the climate change efforts every 5 years and align them with the submission timelines. Hong Kong government has set a carbon intensity reduction target of 65% to 70% by 2030 using 2005 as the base, which is equivalent to 26% to 36% absolute reduction and a reduction to tonnes on a per capita basis. Extracted from Hong Hong s Climate Action Plan 2030+

3 Mitigating Climate Change - RE As part of the Hong Kong s climate actions, Hong Kong is eager to promote renewable energy. Hong Kong government estimates that Hong Kong has only 3-4% of realisable renewable energy potential arising from wind, solar and waste to energy (WTE) that can be exploited based on currently mature and commercially available technologies, Extracted from Hong Hong s Climate Action Plan 2030+

4 Food Waste Problem in Hong Kong In 2015, the amount of food waste was 3,382 tonnes to landfills each day in Hong Kong and it accounted for 33% of all solid waste (10,159 tons/day) Domestic Food Waste: 2,397 tonnes/day C&I Food Waste: 985 tonnes/day Total MSW: 10,159 tonnes/day Extracted from Hong Kong 2015 Municipal Solid Waste - At a glance

5 Food Waste To Energy Anaerobic digestion of converting food waste to biogas is one of the most promising technologies to tackle the food waste disposal problem It is also a good source of renewable energy If 1 tonne of food waste recycled instead of landfilled: CO 2 emission reduced by ~1,600 kg Energy generation of 3.3 GJ (eq. to ~$790 towngas cost) Electricity of kwh of electricity If 3,400 tonnes/day of food waste recycled instead of landfilled: CO 2 emission reduced by ~2 million tonnes per year (~4.6% of Hong Kong s total CO 2 ) Energy generation of 4,336 TJ per year (~1.5% of Hong Kong s total energy) Electricity of 477 million kwh per year (~1.1% of Hong Kong s total electricity)

6 Organic Waste Treatment Facilities (OWTFs) HK Government is planning to build 5-6 OWTFs between 2014 and 2024 with a total recycling capacity of about 1,300 1,500 tonnes per day. Undergoing planning 300 tonnes/day Drawbacks of OWTFs: Lack of suitable sites for further OWTFs Lengthy process to plan and construct the facilities Very costly 200 tonnes/day by 2017? Extracted from A Food Waste & Yard Waste Plan for Hong Kong

7 Insufficiencies of Conventional Centralized Facilities Location & Logistic Difficult to identify suitable sites for centralized facilities and thus mostly located in remote areas Complicated food waste collection from numerous sources and long-distance transportation of food waste Treatment Process Wet and oily Asian food waste different from Western food waste, resulting in operational problems in pretreatment and process stability in digesters, esp. singlestage process Require skillful operation and close process monitoring End-products Besides biogas, compost is produced which has limited market demand and little financial return in Hong Kong Generates highly concentrated wastewater which requires further treatment and proper disposal

8 Decentralized Food Waste System Potential Merits Much simpler and cheaper logistics in food waste collection due to the proximity to the food waste sources; More suitable sites for building decentralized systems than large centralized facilities; Easier control on the quality of sourceseparated food waste, resulting in simpler pretreatment and less process fluctuation; Possible in-situ use of the biogas generated from decentralized systems Prerequisites A new food waste conversion process that is more robust, more compact and easier to operate than the conventional anaerobic digestion facilities End products recovered from food waste need to have high market value in order to achieve financial viability to attract private sector s participation 8

9 Food Waste Recycling Pilot Plant at Sheung Shui A 2-year ITF project commenced in 2014 with support from CityU, Towngas, WIT Holding Lyd., Associated Engineers, Ltd., Hong Kong Organic Waste Recycling Centre Ltd., Green Technology Consortium Ltd., Sunway Environmental Technology Co. Ltd., VTC, EPD After 1 year s laboratory study, a pilot plant of 50 kg/day was set up at Sheung Shui in September

10 3-step Zero Effluent Discharge Process (Patent Pending) Food waste slurry Biogas Auto Food Waste Separator Food Waste Food Waste Decomposition Bioreactor Biogas Production Bioreactor Membrane filtration Ultrasonic System First Step Waste Oil Solid Residue Nutrient Solution Third Step Recycle Water Biodiesel Eco Fish Feed Second Step

11 Pretreatment A patented pretreatment machine was developed to replace the complicated sorting processes for treating Asian food waste. Pretreatment machine automatically separate non-biodegradable matters and break down the organic matters into small particles, producing homogeneous slurry. Food Waste Pretreatment Machine Food Waste Slurry

12 Two-stage Bioreactors Different microbial cultures in two separate bioreactors for food waste decomposition and biogas generation respectively Automatic control to maintain bioreactors at optimum ph and temperature conditions Eliminate interference to the biogas production bioreactor Stable, robust and high efficiency 2-stage biological process, requiring minimal manual attendance Food Waste Decomposition Bioreactor (ph 4-6; ~35 o C; 2-3 days HRT) Biogas Production Bioreactor (ph 6-7; ~35 o C; 7-8 days HRT)

13 Recycling of Food Waste to Valuable Resources Food Waste Decomposition Bioreactor Floatable Oil (10 15 Liter) Biogas Production Bioreactor Biodiesel 1 tonne Food Waste Nutrient Solution (1.8 tonne) Biogas ( m 3 ) Solid Residue ( tonne) Eco Fish Feed 13

14 Protein-rich Solid Residue Parameter Unit Solid Residue (dried form) Fish Feed (Weever) Fish Feed (Tilapia) Moisture g/100g Total Carbohydrates g/100g Protein g/100g Total Fat g/100g Ash g/100g Crude Fibre g/100g

15 Biogas Very stable, consistent biogas production High methane yield ( m 3 biogas per tonne of food waste) High methane concentration (70-80%), minimizing the biogas purification cost

16 Biogas Items Biogas (HKPC Pilot Plant) Towngas Natural Gas CH 4 (%) H 2 (%) trace trace-0.02 Chemical Composition CO 2 (%) CO (%) Nil H 2 S (ppm) Nil (after purification) Nil - Others (%) Physical Properties Calorific Value (MJ/M 3 )

17 Zero Effluent Discharge Effluent coming out of the biogas production bioreactor is filtered by membrane filtration and recycled back to pretreatment This eliminates the setup and operation of wastewater treatment system

18 FTR Food Waste Total Recycling System Merits A robust, compact and easy-to-operate system Food waste fully recovered into 3 high market value products: (i) High purity biogas (~80% methane) (ii) Protein-rich eco fish feed (iii) Quality waste oil for biodiesel production No wastewater discharge Possible in-situ use of biogas Very suitable for decentralized recycling of food waste from local communities / a cluster of food waste sources Can be set up at industrial parks/refuse transfer stations/outlying islands/university campus 18

19 Teamed up with a local company to build a demonstration plant (1 tonne/day) in Zhuhai to promote the developed technology to mainland China Hope to set up a similar demonstration plant (10 tonne/day) in Hong Kong to promote the concept of decentralized food waste recycling Lining up interested parties to support the demonstration project and identifying suitable site Communicating with government departments to figure out relevant regulations The Way Forward 19

20 Thank you!