biogas presentation 05nov19 - iwmsa · 2020-01-27 · biogas – a viable alternative to landfill...
TRANSCRIPT
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Organic WasteA Resource – not a Nuisance
Company logo
here only
Presenter:
Terence SundgrenGlobal Energy Biogas (Pty) Ltd
Director
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2018 South African SoWR (DEA):
Organic Waste – 16%
“Other” Waste – 35%
• Biomass from Sugar mills, Sawmills, P&P
Total Organic Waste ~50%
GreenCape 2019 Waste-Market Intelligence Report:
Organic Waste – 28%
P&P – 13%
Total Organic Waste ~40%
Organic WasteA Resource – not a Nuisance
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What is “Organic Waste”?
Waste that originates from (recently) living organisms
• (Not their activities)!
What is the Nature of Organic Waste?
Generally wet
Carbon-based (has energy potential)
Decomposes readily
Contains plant nutrients
Organic WasteA Resource – not a Nuisance
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What are the most common sources of Organic Waste”?
Food industry
Domestic food waste
Agricultural discard
Abattoirs
Sewage and animal manure
Wood and Paper industry
What problems are associated with Organic Waste?
Odour/Unsightly
Mixed with inorganic waste
Turns to liquid (leachate)
Toxins, pathogens, vectors
Produces Greenhouse gas
• Methane (CH4) >> Carbon Dioxide (CO2)
Organic WasteA Resource – not a Nuisance
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State of Waste Report (SoWR):
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What is good about Organic Waste?
Energy rich
Rich in plant nutrients
Can be “recycled”
Organic WasteA Resource – not a Nuisance
Pertinent Legislation
Western Cape DEA:
• Outright ban on organics to Landfill by 2027
• 50% diversion target for 2022
Waste – Norms and Standards (23 Aug 2013)
• Outright ban of liquid waste to Landfill (6 yr compliance)
• 23 Aug 2019 – In Force!
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What is “Liquid Waste”?
Organic WasteA Resource – not a Nuisance
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What is “Liquid Waste”?
• Tomato – 94% water
• Nectarine – 95% water (excl. stone)
• Cheese – 40-50% water
• Meat – 75% water
What can we do about this?
Organic WasteA Resource – not a Nuisance
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Back To Basics: Four “R’s”
Organic WasteA Resource – not a Nuisance
REDUCE
REUSE
RECYCLE
RECOVER
DUMP
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Back To Basics ORGANICS?
Organic WasteA Resource – not a Nuisance
REDUCE
REUSE
RECYCLE
RECOVER
DUMP
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Back To Basics ORGANICS?
Organic WasteA Resource – not a Nuisance
REDUCE
REUSE
RECYCLE
RECOVER
DUMP
-
Back To Basics ORGANICS?
Organic WasteA Resource – not a Nuisance
REDUCE
REUSE
RECYCLE
RECOVER
DUMP
?
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Back To Basics ORGANICS?
Organic WasteA Resource – not a Nuisance
REDUCE
REUSE
RECYCLE
RECOVER
DUMP
??
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Back To Basics ORGANICS?
Organic WasteA Resource – not a Nuisance
REDUCE
REUSE
RECYCLE
RECOVER
DUMP
??
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How do we Recycle/Recover Organic Waste?
Organic WasteA Resource – not a Nuisance
Fly Farms
Biomass (limited)
• Water is the problem
• 1m3 “food waste” (15% TS) = 3.5MJ (1kWh)
• To “boil off” the water = 2.5MJ
Composting
Biogas
FOOD?
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Biogas – a Viable Alternative to Landfill
Organic WasteA Resource – not a Nuisance
What is Biogas?
• A gaseous mix produced from the anaerobic
digestion of organic substances
• Typically around 60-70% methane (CH4) and 30-40%
carbon dioxide (CO2)
• Can also include small amounts of oxygen (O2),
nitrogen (N2) and traces of hydrogen sulphide
(H2S), and other impurities
• As it is produced in a wet environment, biogas will
typically include significant amounts of moisture
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Organic WasteA Resource – not a Nuisance
What is Anaerobic Digestion (AD)?
• A completely naturally occurring phenomenon
• A sequence of biological processes, facilitated by a
large number of different micro-organisms
(anaerobic bacteria), in an oxygen-free
environment
• The bacteria break down hydrocarbons and
proteins, to form CH4 and CO2 with traces of
impurities such as H2S
• The remaining sludge residue has minimal organic
matter, is high in nutrients (Nitrates, Phosphates
and Potassium) and makes an excellent fertiliser
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Organic WasteA Resource – not a Nuisance
History
• First observed in ancient times as “Marsh Gas”
• May have been used for heating purposes as early
as 16th C
• The first “modern” anaerobic digester was built in
India in 1859
• Domestic and farm-scale biogas plant have
developed rapidly in China and India since 1960’s,
due to government incentives
• Millions of biogas plants in India and 10’s of millions
in China
• In Europe, the past 2 decades have seen an
exponential growth in biogas plants, with Germany
leading the way with over 9 000 operational plants
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Organic WasteA Resource – not a Nuisance
Increase in Biogas Plants in Germany- 1992- 2016
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Organic WasteA Resource – not a Nuisance
Biogas Plants in Europe - 2016
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Organic WasteA Resource – not a Nuisance
Hundreds of Thousands of small bio-digesters in China and
India
So much for Europe and Asia -
what about South Africa???
Biogas industry in its infancy
Off to a rocky start
Some spectacular disasters:
• New Horizons – Athlone
• Zandam Cheese
• Hawequas abattoir
But there are some successes too:
• Bronkhorstspruit (Bio2Watt)
• Elgin Fruit Juice
• Eilenkraal Dairy
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Organic WasteA Resource – not a Nuisance
Potential Feedstock
Manure (cow, pig, sheep, chicken) – most common
feedstock
• 100 cows ~ 4t manure/day (wet)
• 20kW continuous
• 450kWh/day
Sewage
Agricultural waste (non-woody)
Abattoir waste (rumens, blood, DAF)
Food processing waste
Brewery filtrate
Dairy waste
Retail food/market/restaurant waste
Paper pulp
Energy crops?
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Organic WasteA Resource – not a Nuisance
Feedstock to avoid
• Anti-biotic contamination
• Plastic/packaging
• Bone
• Mineral oils
• Abrasive materials
• Cord/wire/rope
• High-saline waste
• Effluent containing heavy metals
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Organic WasteA Resource – not a Nuisance
Biogas Plant Designs Batch-type
• Up to 100% efficient organic removal
• Slow
• Erratic
Lagoon• Not heated
• Large foot-print
• Low-tech
Plug-flow• More sophisticated (heated)
• Faster than lagoon/batch-type
• Low efficiency
Continuously Stirred Tank Reactor (CSTR)• State of the art
• Heated
• PLC-controlled
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Organic WasteA Resource – not a Nuisance
Modern Biogas Design (CSTR)
• Feedstock buffering, pre-treatment, mixing
• Metering of feed to digesters
• Mesophylic (~37°C) / Thermophylic (~55°C)
operation
• Multi-stage digesters (increased efficiency)
• Gas collection and storage
• Gas cleaning & drying
• Combine Heat & Power (CHP)
• Digestate treatment and separation
• Recovered water recycling
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Organic WasteA Resource – not a Nuisance
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Organic WasteA Resource – not a Nuisance
AD Physical Plant
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Organic WasteA Resource – not a Nuisance
Advantages of Biogas
Environmentally sound, sustainable means of
organic waste disposal (90%+ COD reduction)
Recovers (renewable) energy from organic waste
Reduces greenhouse gas (CH4 is an order of
magnitude worse than CO2)
Tax-efficient in South Africa
• 100% deductible in 1st year of operation
• Section 12L, Income Tax Act, 2015
Uses and re-cycles contaminated water/effluent
Returns nutrients to the soil (high NPK’s)
Eliminates pathogens and does not attract vectors
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Organic WasteA Resource – not a Nuisance
2018/19 - 13.87%
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Organic WasteA Resource – not a Nuisance
Biogas in South Africa:What has gone wrong – What lessons can we learn?
2 reasons that biogas projects in South Africa have
failed:
• The WASTE has not been seen as the driver
• Imported “European” technology applied to a
South African setting
The Solution:
Design the plant around the WASTE
Use appropriate, LOCAL technology
Simple, passive, fail-safe control system
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Organic WasteA Resource – not a Nuisance
Rennie Farms Biogas Plant:The only tomato-powered
generator in the world(Wellington – SA)
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Organic WasteA Resource – not a Nuisance
What can make a biogas plant work in South Africa?
Ideal business case:
• Organic waste management must be a key driver
• The Waste must be identified up-front,
characterized and quantified
• The Plant must be designed around the expected
waste stream(s)
• The Plant should ideally be built on, or close to
the waste producer’s property
• The Plant must be designed and built using local
technology, local resources and local materials
• The Plant must be designed for simple, robust
operation all conditions
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Organic WasteA Resource – not a Nuisance
What can make a biogas plant work in South Africa?
Ideal business case cont…
• Power produced should be used by the waste
producer, or nearby user
• Use/disposal of spent digestate should form part
of the business model
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Organic WasteA Resource – not a Nuisance
What can make a biogas plant work in South Africa?
Economics:
• Ideally the biogas plant should generate revenue
(savings) from both waste management and
energy supply
• Ideally the biogas gas should be used for heating,
as a replacement for diesel or paraffin
• If used for electricity generation, waste heat from
the engine must be used to heat the digesters
• Minimum waste supply of 5 tons/day (~100kW(th))
output
• Selling of digestate (as fertilizer or compost)
should NOT be included in the financial model
• Any biogas project must include long-term (10
yr+) agreements for both waste supply and energy
off-take
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Organic WasteA Resource – not a Nuisance
What can make a Biogas Plant work in South Africa?
Actual business case:
• Pig farm with 6 000 sows, 10 000 piglets,
producing 160 tons of manure per day
• Plant (on-site) will produce 250kW (avg cont.)
electricity supply, with a peak output of 400kW
• Pig farm power usage: 240kW, with 350 kW peak
• Spent digestate will be separated. Solid fraction
used for bedding. Liquid fraction sent to irrigation
dam for crop irrigation
• Cost of Plant: R5 875 000 (R23 500/kW)
• Eskom avg electricity price: R1.13/kWh
• Current Eskom bill: R2 375 712 p.a.
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Organic WasteA Resource – not a Nuisance
What can make a Biogas Plant work in South Africa?
Actual business case:
• Dairy farm with 1 000 cows, producing 80 tons of
manure per day
• Plant (on-site) will produce 185kW (avg cont.)
electricity supply, with a peak output of 500kW
• Neighbouring animal feed business consumes >400
kW (avg cont.) with >800kW peak
• Spent digestate will be separated. Solid fraction
used for bedding. Liquid fraction sent to irrigation
dam for crop irrigation
• Cost of Plant: R6 350 000 (R34 325/kW)
• Eskom avg electricity price: R1.42/kWh (Peak &
Standard)
• Annual saving: R2 240 000 p.a.
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Organic WasteA Resource – not a Nuisance
What will prevent a Biogas Plant from working in
South Africa?
Capital cost of plant too high
Plant too complex and unforgiving for reliable
operation with local resources
Waste stream too variable/too little/low BMP
Waste contaminated with foreign material
Insufficient space for bio-digester footprint
Energy too cheap (coal-fired boiler)
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Organic WasteA Resource – not a Nuisance
Biogas Bottom-line:
Biogas offers both an Organic Waste Management, and
Renewable Energy solution
Anaerobic Digestion has proven itself in other parts of
the world
The technology can be adapted to suit the South
African situation
Biogas is economically viable in South Africa, today,
and will only increase in value in the future
After a rocky start, and lessons learnt, the future of
Biogas in South Africa is huge
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Organic WasteA Resource – not a Nuisance
Thank You!
Questions?