Food Waste to Biogas Technology Environmental Management Division - - PDF document

Food Waste to Biogas Technology

Environmental Management Division Ir Dr. Anthony MA 10 Dec 2016

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Extracted from “Monitoring of Solid Waste in Hong Kong – Waste

Statistics for 2014”

Food Waste Problem in Hong Kong

Food Waste: 3,641 tonnes/day Over 1/3 of Total MSW

Yard Waste & Others: 515 tonnes/day Total MSW: 9,782 tonnes/day

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Food Waste Arising from C&I Sources

• The amount of food waste arising from C&I sources, such as restaurants,

hotels, wet markets and food production & processing industries has increased steadily.

Extracted from “Monitoring of Solid Waste in Hong Kong – Waste

Statistics for 2014”

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C&I Food Waste Generation in Mainland

• China produces 50,000,000 tonnes/year food waste (137,000 tonnes/day)
• Food waste accounts for ~70% of China's mounting garbage

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Food Waste Management Strategy

Extracted from EPD website

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Design of Biogas Pit

Organic Waste Treatment Facilities (OWTF)

Electricity generation

Biogas

Compost for landscaping or agricultural application 200 tonnes food waste per day

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Complicated Logistics

OWTF in Siu Ho Wan

Wastewater treatment

• Initial capital investment: HK$1.5 billion
• Running cost: HK$72.4 million/year

(HK$992 per tonne food waste)

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Extracted from “A Food Waste & Yard Waste Plan for Hong

Kong 2014 – 2022” , February 2014

• 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

Organic Waste Treatment Facilities (OWTFs)

200 tonnes/day by 2016 300 tonnes/day By 2017 Undergoing EIA

Drawbacks of OWTFs:

• Even with 6 OWTFs, can only

handle 50% of total food waste

• Lack of suitable sites for

OWTFs

• Huge investment

?

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Food Waste Recycling Pilot Plant at Sheung Shui

• A 2-year ITF project commenced in 2014 with support from CityU, Towngas,

Associated Engineers, Ltd., Hong Kong Organic Waste Recycling Centre Ltd., Green Technology Consortium Ltd., WIT Holding 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 2015

Project Team

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Project Coordinator

• Dr. Anthony Ma

Deputy Project Coordinator

• Dr. Vinci Lee

Engineering Design Billy Cheung William Lo Wong Kin Wai Cheuk Chun Yeung Lab & Pilot Studies

• Dr. Susana Wu

Dennis Tang Pilot Plant Operation Barry Bi Ho Chi Tung Alan Lam

External Microbiological Expert

• Dr. Patrick Lee

(CityU)

External Gas Utilization Expert

Towngas

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Natural Bacterial Decomposition of Food Waste

1 tonne Food Waste

• 4. Biogas

Production Bioreactor Biodiesel Biogas(130-160 m3) Eco Fish Feed Nutrient Solution

FTR Food Waste Total Recycling System

(patented)

• 3. Food Waste

Decomposition Bioreactor

• 2. Ultrasonic System
• 5. Membrane

filtration Food waste slurry Recycle Water

• 1. Auto Food Waste

Separator

First Step Second Step Third Step

Waste Oil Solid Residue

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Specialized Microbes for Food Waste Decomposition

Decomposition Bioreactor

Leuconostoc Lactobacillus Lactococcus

Fermentation of sugars to lactic acid, ethanol or acetate Production of lactic acid Production of lactic acid during glucose fermentation 14

Specialized Microbes for Biogas Production

Methanogenesis Bioreactor

Methanosarcina Methanosaeta Methanofollis

High affinity for acetate- methane producer Anaerobic methanogens Anaerobic bacteria use CO and H2 to produce methane

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Biogas Generation from Methanogenesis

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Compare Biogas with Town Gas / Natural Gas

Biogas vs Other Combustible Gases

Items Biogas (HKPC Pilot Plant) Town Gas Natural Gas Chemical Composition CH4 (%) 70-80 28.2-30.7 87-97 H2 (%) trace-0.006 46.3-51.8 trace-0.02 CO2 (%) 15-25 16.3-19.9 0.1-1 CO (%) Nil 1-3.1

• H2S (ppm)

Nil (after purification) Nil

• Others (%)
• 0-3.3

5-10 Physical Properties Calorific Value (MJ/M3) 28-32 17 36-40

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Protein-rich Solid Residue Analysis

Recycling of Food Waste to Valuable Resources

Item Unit Dried Sludge Fish Feed for 鱸魚 Fish Feed for 羅非 Moisture g/100g 8.3 8.15 8.01 Total Carbohydrates g/100g 20.5 17.2 46.9 Protein g/100g 39.9 45.5 31.3 Total Fat g/100g 17.7 16.3 5.73 Ash g/100g 13.6 12.9 8.07 Crude Fibre g/100g 4.03 1.71 7.26 Cost HKD/kg

• 15

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Recycling of Food Waste to Valuable Resources

Food Waste Food Waste Decomposition Methanogenesis Biodiesel Biogas (130 – 160m3) Eco Fish Feed Floatable Oil Nutrient Solution Solid Residue

• Patented pretreatment to ground and separate digestible organic

substances from the trash instead of complicated waste sorting;

• Generation of valuable recyclable products to maximize financial

return;

• High specific yield of methane per kg of food waste (130-160 m3

biogas per tonne of organic);

• High methane concentration reaching approx. 80%, minimizing the

biogas purification cost;

• Other than the trash, 100% of the organic fraction is converted into

reusable products, leaving no residual waste;

• Much stable and robust 2-stage biological process, requiring minimal

level of operator attendance;

• Compact system with minimal space requirement.

Merits of the Developed System

Thank you !

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