Current RDI to find alternative solutions Anaerobic Digestion of Organic Waste

Transcription

1 0&/"! &%/0) &%#( Current RDI to find alternative solutions Anaerobic Digestion of Organic Waste By: Professor Cristina Trois #0&Y- ( 0C(<>>_( &7(@CA7BA9K 9C6(U@6I (6I 9(0C69:CGM7CGB( ' 7J C5@B(H7:(! 9E9G:5I (GCN(0CC7AGM7C(@C( [ 7CE6:J 5M7C(]' 0[ ^( Dean and Head of School of Engineering, University of KwaZulu-Natal Chair of Southern Africa Regional Secretariat of UN-IPLA Programme and IWWG Q ( /1` _(((((( INDUSTRY-MEETS-SCIENCE WORKSHOP Technology solutions for addressing biomass and organic waste UKZN November 2014 ; <P; >P<>; ; ( 0&/"! $0"Q R(! "- "%! '. (2! ) *"- - )! ( *! %' /0) &%#(%22) 0&/+ "&/R(' %"- R( %"- >; P<>; ; (

2 OUTLINE National waste management strategy in South Africa and implementation of the waste hierarchy Brief description of available waste strategies for Local Authorities Waste & Resource Optimisation Strategy Evaluation Model W.R.O.S.E Decision-making tool for assisting municipalities in the selection of appropriate waste management strategies Examples of Public Private Partnership waste projects in South Africa (KwaZulu-Natal Province)

3 3 Why bio-energy in developing countries?

4 4 Simplified biogas process

5 5 Factors affecting the design of AD plants in DCs

6 6 Percentage of households that uses various fuels in South Africa

7 7 Potential for bio-energy in rural South Africa

8 8 Biogas yield of various substrates

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11 11 Types of AD plants for DCs Fixed dome reactor Advantages: Relatively cheap, approximately two thirds the cost of the floating drum -Durable with relatively long life of approximately 20 years No steel parts that may corrode Underground construction that saves space Disadvantages: They are difficult to construct on bedrock Require highly skilled labour with experience in brick laying so that the overall construction is airtight It usually fails due to cracking during cement curing and/or differential settlement of the structure Gas pressure fluctuations

12 12 Types of AD plants for DCs Flexible Balloon Reactor Advantages Low cost Utilizes simple technology that does not required highly skilled labour Suitable for shallow construction especially if the water table is high Easy to transport Easy cleaning, emptying and maintenance Disadvantages Short life span of approximately 5 years. Balloon skin is easily damaged and difficult to repair Does not create any local employment

13 13 Types of AD plants for DCs Floating Drum Digester Disadvantages Expensive to construct, approximately 50% greater than the fixed dome digester Requires regular maintenance such as priming, painting and coating to prevent rusting of the steel and so the drum is air tight Metal parts are susceptible to corrosion Advantages Offers the most consistent pressure due to the weight of the drum which keeps the produces biogas under pressure. Volume of biogas produced is visible by the level of the gas drum

14 Challenges in setting up AD plants in DCs 14 Real acceptance of the technology depends on individual Biogas may be considered to be a dirty technology in areas in Sub-Saharan Africa, producing food of inferior taste compared to food prepared by traditional wood biomass or modernized energy The aim of the system is to substitute energy and fertilizer previously purchased or collected but with local traditional and conventional energies that are abundant and at low prices, farmers have fewer incentives to adopt biogas technology Investment of the technology is dependent on the user s income The technology requires regular operation after installation Lack of domestic animals to meet minimum manure requirements for sufficient biogas production Limited water resources hampers the communities ability to utilize the biogas technology

15 Integrated waste treatment system

16 CDM Landfill Biogas-to-Energy Project 16 1 st CDM Landfill Biogas-to-Energy Project in Africa Bisasar Rd landfill - extracts approximately 350 m 3 /hour, Component 1 produces approx. 9MWh Mariannhill landfill -180 m 3 /hour is produced and an estimated 1775 m 3 /hour by Approximately 900 kwh of electricity is generated

17 Integrated waste treatment system

18 Material Recycling Facilities (MRF) JOB CREATION POTENTIAL A small dirty-mrf processing 160 to 250 tpd can employ up to 150 on a full time basis

19 Food Wastes AD FOOD WASTE SEPARATION AT SOURCE Feed Tanks & Maceration Unit ANAEROBIC DIGESTION (AD) & BIOGAS PRODUCTION Production of Biogas (CH 4, CO 2 ) Anaerobic Digestion (AD) Reactor AD Biogas to Gas Generator Destruction of Methane (CH 4 ) Generation of Electricity GENERATION OF ELECTRICITY Possible Transformer Digestate Storage Tank COMPOSTING OF AD DRY-DIGESTATE Gas Pump & Flare Station Biogas Engine and Electricity Generator AGRICULTURAL USE OF AD WET & DRY DIGESTATE Schematic Layout: Proposed Anaerobic Digestion (AD) Food Waste Treatment Plant (not to scale)

20 Biological Anaerobic Digestion (AD) UTS Clarke-Haase Kuettner Throughputs- from 5,000~10,000 to 150,000+ tpa Subject to AD type, (scalable, expandable subject to technology) Cost of technology- Expensive, subject to plant compliance requirement (ABPR) Energy balance- Produces BiogasHeat, Electricity, Vehicle Fuel, Industry, JOB CREATION POTENTIAL 4 to 6 permanent jobs are created per ton of waste provided to an AD plant. An AD plant that treats 12k tpa (35tpd) could generate over 200 permanent jobs.

21 AD Bankability Factor to be considered Typical feedstocks Wet AD Dry AD (low solids) Dry AD (high solids) Low solids liquid products, dairy products, food waste only, fruits and vegetable Food waste, fruits, medium and high solids liquid products, some green waste Flexibility in feedstock fluctuation Low Medium High Ease of expansibility Low /None Medium High Scalability Medium: from 5-8,000 High: from 1,000 tpa tpa subject to subject to technology technology Food waste, green waste (as bulking agent), fruit and vegetable, putrescible high solid content products Medium from 8-10,000 tpa Footprint required Low Medium High Primarily Liquid Liquid and solid Outputs Primarily Solid digestate digestate digestate OPEX High Medium Low Example: AD Plant 12k tpa may realise up to 0.5MWe at a total capex of some R30-40m (approx. 2-3m EURO).

22 AD & EfW Bankability

23 Scenario Analysis for Municipalities 23 Zero Waste Model Assist LAs in formulating sustainable WM strategies Resource recovery (i.e., waste-to-energy) Quantitative assessment of GHG reduction & landfill space savings Waste stream analysis: knowledge gaps Financial feasibility leading to scenario analysis

24 24 Dry-wet waste diversion model

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26 What is the W.R.O.S.E model? 26 WROSE = Waste & Resource Optimisation Scenario Evaluation WM Strategies: landfill, landfill gas recovery, recycling, AD and aerobic composting Evaluates GHG emissions reductions from applying waste diversion strategies Emission factors developed by the US EPA for WM strategies and together with an estimated emissions factor for AD Microsoft Excel Spreadsheet Interface

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28 28 WROSE Model Input Screen

29 29 WROSE Model Output Screen

30 Case Study: UMDM 7 local municipalities 5 landfills currently people Population Growth: 0.87% Waste Growth: 1.088% tonnes of Waste per year

31 31 Assessment of New England Road

32 32 Marianhill Waste Stream

33 33 Marianhill Waste Stream

34 34 New England Economic Analysis

35 Potential for Landfill Biogas-to-Energy

36 Anaerobic Digestion of Food Waste 36 Partnership: UKZN-Don t Waste Services-THRIP 0.5 MW (12 MWh) AD Plant on Howard College Campus to process tons of macerated food waste and food processing waste per day Emissions reduction = approx tons of CO 2 eq. per annum Digestate/compost material = approx. 95 tons per month Partnership: DubeTrade Port-UKZN-THRIP (Dti) 0.5 MW (12 MWh) AD Plant in the AgriZone to process tons of macerated food waste and food processing waste per day Emissions reduction = approx tons of CO 2 eq. per annum Digestate/compost material = approx. 95 tons per month

37 Energy Recovery from Farm Waste 37 Biomass potential in KwaZulu-Natal, South Africa High levels of animal husbandry with poor waste management practices Significant quantities of organic waste available Significant potential to reduce current GHG emissions Paradigm shift: Waste as an opportunity!

38 Dairy Waste AD Plant-Underberg, KZN 38 Prefeasibility study conducted using Induced Blanket/Bed Reactor AD Plant and industry standards for Biogas production from cow manure Biogas used to run gas powered electrical generators electricity used for farm/dairy operation (financial benefit) Reduced GHG emissions NOT Financially feasible under baseline assumptions Cows kept in open pastures (no waste collection), and rotary dairy system highly efficient (low level of waste collection) Advanced Rotary Dairy system with cow retention time of approx. 11 minutes

39 39 Prefeasibility Assessment Piggery AD Plant in Ashburton, KZN 5000 pigs producing approx tonnes of wet organic waste per annum Biogas yield of 694m 3 per day Energy output per year approx kwh FINANCIAL FEASIBILITY IDENTIFIED Energy cost offset = internal rate of approx. return 7%

40 Waste-to-energy in rural SA 40 Case study UKZN-WRC Project (k5/1955) New application to LOTTO for 10 small AD plants (Mkuze Game Reserve) Objective: improve living standards in rural households through integrated waste, water and energy sustainable technology solutions Integrating rainwater harvesting, livestock fodder production and biogas generation in rural areas of South Africa 4 pilot study households in each province

41 Conclusions Need for GIS mapping of regional landfills Comprehensive waste stream analysis and carbon footprint assessment required to develop projects Need for an integrated sustainable waste management decision-making framework for local authorities Need for ad hoc capacity building within municipalities Scenario and Technology Assessment (through the use of tools like WROSE) prior to financial commitment, towards a sound bankable feasibility report Streamline success of projects through the creation of synergic special purpose vehicles between private and public actors

42 0&/"! &%/0) &%#( #0&Y- ( 0C(<>>_( &7(@CA7BA9K THANK 9C6(U@6I YOU (6I 9(0C69:CGM7CGB( ' Prof. 7JCristina C5@B(H7:(! Trois 9E9G:5I (GCN(0CC7AGM7C(@C( [ Dean/Head of School of 7CE6:J Engineering 5M7C(]' 0[ ^( University of KwaZulu-Natal Q ( /1` _(((((( Tel: /65 troisc@ukzn.ac.za ; <P; >P<>; ; ( 0&/"! $0"Q R(! "- "%! '. (2! ) *"- - )! ( *! %' /0) &%#(%22) 0&/+ "&/R(' %"- R( %"- %"- >; >; P<>; P<>; ; (