Biogas Presentation 05Nov19 - IWMSA · 2020-01-27 · Biogas – a Viable Alternative to Landfill...

Organic WasteA Resource – not a Nuisance

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Presenter:

Terence SundgrenGlobal Energy Biogas (Pty) Ltd

Director

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%


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


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)


State of Waste Report (SoWR):

What is good about Organic Waste?

Energy rich

Rich in plant nutrients

Can be “recycled”


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!

What is “Liquid Waste”?


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?


Back To Basics: Four “R’s”


REDUCE

REUSE

RECYCLE

RECOVER

DUMP

Back To Basics ORGANICS?


REDUCE

REUSE

RECYCLE

RECOVER

DUMP



REDUCE

REUSE

RECYCLE

RECOVER

DUMP

?



REDUCE

REUSE

RECYCLE

RECOVER

DUMP

??



REDUCE

REUSE

RECYCLE

RECOVER

DUMP

??

��

How do we Recycle/Recover Organic Waste?


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?

Biogas – a Viable Alternative to Landfill


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


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


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


Increase in Biogas Plants in Germany- 1992- 2016


Biogas Plants in Europe - 2016


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


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?


Feedstock to avoid

• Anti-biotic contamination

• Plastic/packaging

• Bone

• Mineral oils

• Abrasive materials

• Cord/wire/rope

• High-saline waste

• Effluent containing heavy metals


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


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


AD Physical Plant


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


2018/19 - 13.87%


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


Rennie Farms Biogas Plant:The only tomato-powered

generator in the world(Wellington – SA)


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



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



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


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.


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.


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)


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


Thank You!

Questions?

Date post:	17-May-2020
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Biogas Presentation 05Nov19 - IWMSA · 2020-01-27 · Biogas – a Viable Alternative to Landfill...

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