The Role of Anaerobic Digestion Technology in Treating Organic Waste - - PowerPoint PPT Presentation

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The Role of Anaerobic Digestion Technology in Treating Organic Waste – UK Experience

Presentation to GreenCape Networking event, 23rd August 2016

Andrew Street Director, SLR Consulting astreet@slrconsulting.com

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PRESENTATION OVERVIEW

Setting the scene – technology options and selection The UK journey towards a circular economy and the role of waste treatment technology The role that Anaerobic Digestion is playing in treating organic waste streams South African Case Study Conclusions

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PRESENTATION OVERVIEW

Setting the scene – technology options and selection The role that Anaerobic Digestion is playing in treating organic waste streams The UK journey towards a circular economy and the role of waste treatment technology South African Case Study Conclusions

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EMERGENCE OF THE CIRCULAR ECONOMY

• Historic linear model of ‘take-make-consume

and dispose’ assumes resources are abundant, available and cheap to get rid of

• The last 10-15 years has seen a dramatic

change in the way we view and treat waste.

• The ‘Circular Economy’ sees waste as a

resource – Materials reclaimed and reused or recycled as secondary raw materials for new products – Organic waste a source of soil nutrients – Energy generated from any residual waste that cannot be recycled

• Reduces pressure on natural resources /

supply chains

• Contributes to sustainable economic growth

and employment

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PRINCIPAL WASTE TREATMENT / CONVERSION TECHNOLOGY OPTIONS

• Non-thermal:

(Note that all these technologies are intermediate processes and markets are required for the products)

• Thermal:
• Landfill will still be required for final post-treatment residues (but much reduced

quantities)

• Composting [organic waste]
• Anaerobic Digestion (AD) [principally organic waste]
• Mechanical Biological Treatment (MBT / RDF production)
• Mechanical Heat Treatment – Autoclaving [residual waste]
• Incineration with energy recovery [residual waste / RDF]
• Advanced Thermal Treatment (ATT - gasification / pyrolysis /

plasma arc) [principally RDF / refined RDF]

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TECHNOLOGY SELECTION – CRITICAL ISSUES

• National / Provincial / Municipality strategy and policy
• Collection strategy (segregated or mixed streams) and impact on composition -

and future changes

• Seasonal variations in composition (impact on input stream)
• Financial drivers:
• Availability and cost of landfill
• Landfill or incineration levies / taxes (current or future)
• Enhanced tariffs for renewable energy generation / use
• Status of the technology (fully commercial or otherwise) and ‘bankability’
• Markets for process outputs (demand and commercial context):
• Recyclable streams (quality and variability of outputs)
• Compost / digestate (quality and variability of outputs)
• Compost like output / RDF / biomass (quality of outputs)
• Bio-fuels

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MAIN PITFALLS AND LESSONS FROM THE PAST

• Failure to properly understand the waste flows – quality and quantity
• Failure to recognise that the waste is variable and will change significantly over time
• Failure to match waste feedstock (including variability) with technology
• Failure to select technology that is proven - and therefore ‘bankable’
• Failure to understand the character of the process outputs
• Failure to have established, sustainable and commercially viable markets for all

process outputs

• Failure to recognise that market demands can, and will change over time

Success comes through a thorough understanding of waste flows, technology and markets for process outputs – and the interfaces

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PRESENTATION OVERVIEW

Setting the scene – technology options and selection The UK journey towards a circular economy and the role of waste treatment technology The role that Anaerobic Digestion is playing in treating organic waste streams South African Case Study Conclusions

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THE UK JOURNEY TOWARDS A CIRCULAR ECONOMY

• In Europe we have EU-wide legislation in place to force biodegradable

waste away from landfill to alternatives

• Relatively high targets for recycling (50% plus)
• Some countries have landfill bans, some have landfill levies
• Many have renewable energy incentives (Feed-in Tariffs, etc)
• The drivers have therefore been in place over the last 10-15 years to plan

and develop new waste collection / treatment and disposal infrastructure

• In the last 5-10 years one of the largest waste management markets in the

world has been the UK (around R175* billion spend to 2020)

• Many hundreds of new facilities have been built, are under construction, or

are planned – of all types

• The knowledge gained of every type of treatment / management

technology is therefore extensive – we’ve learned how to make choices!

*NOTE – Current (August 2016) exchange rate R / £ of 17.5

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KEY DRIVER – LANDFILL LEVY EVOLUTION

Initially set at R140/tonne Escalator set at R140/tonne; Levy has now reached R1,500tonne (and increasing with inflation)

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ORGANICS: ANAEROBIC DIGESTION

• The latest map of UK AD

facilities (opposite) shows a significant number of existing plants, and a proliferation of prospective sites.

• Please note that this map

includes ADs with feedstock including segregated food waste, food processing wastes, agricultural wastes and energy crops (but excludes sewage treatment works).

• Existing plants
• Prospective plants

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ANAEROBIC DIGESTION (continued ...)

• The UK has seen recent rapid growth in AD capacity
• This has led to concerns over the over provision of AD capacity

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AD FACILITIES (continued ...)

Top 20 largest AD facilities (focussing on those which are operational or in construction):

Updated

Operator Facility name Status Throughput (ktpa) Area

ReFood Dagenham AD In construction 160 Dagenham Earthly Energy In construction 129 North Yorkshire Lake District Biogas Ltd Lake District Biogas AD In construction 126 Wigton Biffa Biffa - Cannock (Poplars) Operational 120 Cannock PDM ReFood Operational 115 Doncaster BioConstruct NewEnergy Ltd Imperial Park AD In construction 110 Middlesborough Rockscape Energy Ltd Operational 101 North Moor Farm Shanks Cumbernauld / Orgworld Operational 100 Glasgow BRITISH SUGAR PLC Bury St Edmunds In construction 97 Bury St Edmunds Roseisle Speyside Whisky Distillery Roseisle Speyside Whisky Distillery Operational 90 Roseisle PDM ReFood Operational 90 Widnes Diageo Ltd Glenfiddich Distillery Operational 88 Keith AC Shropshire Ltd Green Lodge Farm Operational 86 Leicester Corsock Farm Corsock Farm Operational 80 Dalbeattie JFS Clapham Lodge Biogas Ltd Clapham Lodge In construction 80 Northallerton Tamar / Fred Walter & Sons Ltd Operational 76 Sutton Grange

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UK INCENTIVES TO SUPPORT DEVELOPMENT OF AD

• Feed-in Tariffs( generation tariff and export tariff)
• Renewable Obligation Certificates – currently set at 1.8 ROCs/MWh. The value of

ROCs varies as they are traded. Replaced by Contracts for Difference (CfD) for larger generators of 5MWe and above.

• Renewable Heat Incentive (RHI), provides a fixed income (per kWh) to generators of

renewable heat, and producers of renewable biogas and bio-methane. Current rates:

Facility Size Pence / kWh Rand / kWh Total installed capacity of 250kWe or less 7.39 1.293 Total installed capacity between 250kWe and 500kWe 6.82 1.194 Total installed capacity in excess of 500kWe 7.03 1.230 Facility Size Pence / kWh Rand / kWh Small biogas combustion (less than 200 kWth) 7.5 1.312 Medium biogas combustion (between 200 and 600 kWth) 5.9 1.032 Large biogas combustion (greater than 600 kWth) 2.2 0.385 Bio-methane injection (all scales) 7.5 1.312

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• Existing and prospective pre-

treatment facilities (shown

• pposite) outnumber thermal

processing plants

• Established
• Newly developed
• Prospective

RESIDUAL WASTE: PRE-TREATMENT FACILITIES

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PRE-TREATMENT FACILITIES (continued ...)

• Existing – 50 facilities operational or in construction (6 Mtpa capacity).
• Prospective – facilities with planning granted / proposed would double capacity to 12 Mtpa

(though again many will not be realised).

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THERMAL FACILITIES

• Established
• Newly developed
• Prospective
• The map opposite illustrates

locations of UK conventional thermal facilities.

• Plants shown include:
• ‘Established’ plants –
• perational in, or before,

2008.

• ‘Newly developed’ plants

– operational post 2008, or in construction.

• ‘Prospective’ plants –

which have planning permission granted, or are at the proposal stage.

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THERMAL FACILITIES (continued ...)

• Existing – 41 facilities operational or in construction (over 10 Mtpa capacity)
• Prospective – the same amount of capacity again with planning granted / proposed (though many
• f these will not be realised).

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• Existing ATT facilities (mapped
• pposite) are currently much less

numerous than incineration.

• ... however a large number of

prospective facilities have been put forward.

• Existing plants
• Prospective plants

ADVANCED THERMAL TREATMENT FACILITIES

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ADVANCED THERMAL TREATMENT FACILITIES (continued ...)

• Existing – only two known operational residual waste ATT facilities on a significant scale

(Avonmouth – New Earth and Isle of Wight – Energos / Biffa.), with a further four in construction.

• A further 72 prospective plants – though likely that only a small proportion of these will be

realised.

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OVERALL IMPACT ON LANDFILL: 90%+ DIVERSION BY 2020

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PRESENTATION OVERVIEW

Setting the scene – technology options and selection The UK journey towards a circular economy and the role of waste treatment technology The role that Anaerobic Digestion is playing in treating organic waste streams South African Case Study Conclusions

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ANAEROBIC DIGESTION

Basic Description: Suitable feedstock includes:

• Food waste – high biogas yields
• Green / garden wastes – moderate /

low biogas yields

• Sewage sludge / livestock slurry –

low biogas yields

• Energy crops (maize / silage) – high

/ moderate biogas yields

The main AD processes include:

• Wet / dry digestion
• Single stage / two stage
• Mesophillic (~37C) / Thermophillic (55-

59C)

• Batch flow / continuous flow process
• Post-treatment as required to meet

any quality standards for digestate

The bacterial breakdown of suitable organic materials in controlled conditions and in the absence of oxygen producing methane-rich biogas and digestate

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ANAEROBIC DIGESTION: EXAMPLES

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ANAEROBIC DIGESTION: KEY ISSUES / RISKS

Benefits:

• Proven technology with long history of

use;

• AD biogas (methane) provides

renewable energy options as heat, electricity, bio-methane vehicle fuel;

• Output is well-suited for end-use as

compost with beneficial properties;

• Bio-stabilisation of feedstock achieved in

less time than for aerobic processes;

• Fully enclosed wet process – minimises
• dour, particulate and bio-aerosols;
• Income from sale of electricity, heat

and/or methane;

• Carbon neutral process.

Key issues / risks:

• Higher capital costs compared to

in-vessel composting;

• Complex process that requires

close managing and with higher maintenance / opex costs than IVC;

• Quality and variability of

feedstock impact on performance;

• Identifying a sustainable market

for use of digestate;

• Reliance in enhanced energy

tariffs to underpin commercial viability.

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• 200

400 600 800 1,000 1,200

2010 2011 2012 2013 2014

UK electricity generated by anaerobic digestion (GWh)

AD IN THE UK – ENERGY GENERATED ANNUALLY

27 10 20 30 40 50 60 70 80 0 to 10 10 to 20 20 to 30 30 to 40 40 to 50 50 to 60 60 to 70 70 to 80 80 to 90 90 to 100 100+

Number of AD facilities Feedstock capacity (ktpa) Proposed Planning granted In construction Operational

AD IN THE UK – FACILITIES BY DESIGN CAPACITY

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20 40 60 80 100 120 0 to 0.5 0.5 to 1 1 to 1.5 1.5 to 2 2 to 2.5 2.5 to 3 3 to 3.5 3.5 to 4 4 to 4.5 4.5 to 5 5+

Number of AD facilities Rated power output (MW)

Proposed Planning granted In construction Operational

AD IN THE UK – FACILITIES BY POWER OUTPUT

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CASE STUDY 1 – Anaerobic Digestion Plant, London

• Client: Foresight Group (private equity)
• Location: Dagenham, London
• Scale of Plant:
• 20,000 tpa IVC (green waste)
• 30,000 tpa wet AD (segregated food

waste)

• Energy output: 1.5MWe (gas engine, power export

to grid)

• Waste heat to be connected to district heating

system

• Technology provider:
• IVC – TEG
• AD – Anaergia / UTS
• Gas engines – Pro2 (German)
• Capital cost: R350 million (Investec / Foresight /

GIB / LWARB)

• Operating costs: R21 million/annum (approx)
• Date commissioned: February 2012
• Principal challenge: de-packaging equipment

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CASE STUDY 2 – Anaerobic Digestion Plant, Dunfermline

• Location: Dunfermline, Scotland
• Scale of Plant:
• 43,000 tpa dry fermentation AD (40,000 of

co-collected green and food waste; 3,000 of commercial food waste)

• Energy output: 1.6MWe (gas engine, power export

to grid)

• Digestate: good quality compost for sale
• Waste heat connected to district heating system
• Technology provider:
• AD – BioFERM (Viesmann Group)
• Gas engines – ENER-G / MTU
• Capital cost: R245 million
• Operating costs: R15 million/annum (approx)
• Date commissioned: Mid-2014
• Why dry fermentation?:
• Suited to co-mingled food and garden waste with high dry solids content.
• Suited to operation by local authority direct staff - waste handling
• perations similar to other waste management activities
• No dewatering so significantly reduced liquor (compared to ‘wet AD’ systems)

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CASE STUDY 3 – Anaerobic Digestion Plant, Somerset, England

• Location: South Petherton, Somerset
• Scale of Plant:
• 48,100 tpa wet AD (37,100 of agricultural

crops; 11,000 of animal manure / slurry)

• Energy output: 4.2MWth (gas upgrade and export

to natural gas grid)

• Digestate dewatered and used by local farmers
• Technology provider:
• AD – Biogest
• Gas upgrade – DMT
• Capital cost: R157 million
• Operating costs: R29.5 million/annum
• Date commissioned: under construction

(completion early 2016)

• Principal challenge: gas upgrade relatively new

to the UK (well proven in other parts of Europe)

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PRESENTATION OVERVIEW

Setting the scene – technology options and selection The UK journey towards a circular economy and the role of waste treatment technology The role that Anaerobic Digestion is playing in treating organic waste streams South African Case Study Conclusions

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BIODIGESTION IN SOUTH AFRICA

• The country already has hundreds of

small-scale bio-digesters in rural areas (with gas used for cooking / heating/ lighting etc)

• There are <40 registered commercial

biogas digesters, larger than 100kW, typically on farms, abattoirs, dairy factories etc, i.e. off-grid

• Of these, there are around 12 industrial-

scale AD plants at scale >250kW. Almost all of these are for ‘embedded generation’, i.e. use of power for onsite industrial facility. Includes plants at industrial /municipal wastewater treatment works

• Excludes Landfill Gas plants (e.g. Cape

Town, Durban, Jo’burg) and co- generation projects in the sugar industry

Key Drivers for Development of AD in South Africa:

• Energy Security;
• Feedstock availability;
• Increasing cost of landfill; and
• Government policies.

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Plant Details:

• Installed Capacity: 4.6 MWe
• Location: Beefcor Farm, Tshwane City, Gauteng
• Investors: Norfund, Bio2Watt, Chlorophyll,

Bertha, Bosch;

• Lender: Industrial Development Corporation,

Johannesburg

• Feedstock: 120,000tpa of mixed organic

(agricultural and food processing) wastes

• Offtakes: BMW SA car plant (PPA) & c.20,000

tpa fertiliser to Beefcor farm.

• Constructed by Bosch Projects (as EPC) using

Combigas (Denmark) digestion technology (2 x stage thermophillic / mesophillic process) ;

• Plant produced first power to Eskom grid in

October 2015 (via 4 no. Caterpillar CHP engines);

• Beefcor Site = one of SA’s largest beef cattle

feedlots; also close to grid connection, feedstock sources and has on-site water supply dams;

• Process includes dewatering to recover liquor for

recirculation and solid digestate for beneficial application to Beefcor farm.

CASE STUDY 4 – Bronkorstspruit Biogas Plant, Gauteng Province

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Bronkorstspruit Biogas Plant – Feedstock Supply

Feedstocks Tonnes / a

Solids Cattle Manure 45,000 Paper sludge 24,000 Liquids Fruit & Veg 8,000 Chicken Abattoir 7,000 Food sludge 6,000 Yogurt 5,000 Ice cream 3,000 Fat Trap 2,000 Total 100,000 +

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PRESENTATION OVERVIEW

Setting the scene – technology options and selection The UK journey towards a circular economy and the role of waste treatment technology The role that Anaerobic Digestion is playing in treating organic waste streams South African Case Study Conclusions

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CONCLUSIONS

• The ‘Circular Economy’ sees waste as a resource
• Materials reclaimed and reused or recycled as secondary raw materials for new

products

• Organic waste a source of soil nutrients
• Energy generated from any residual waste that cannot be recycled
• Focus often on the front end of product design and waste prevention / reuse – rightly

so

• Provision for the treatment and reprocessing of segregated material streams, and the

residual stream, is equally important if a move away from landfill reliance is to be achieved

• National and Provincial Government and Municipalities have the greatest ability to

influence decisions on technology selection through policies, byelaws and contractual / procurement decisions.

• The application of Anaerobic Digestion for the treatment of a range of organic wastes

can play a key role in circular economic thinking

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AD - A VIRTUOUS CIRCLE!

Organic wastes processed through AD to generate biogas and nutrient rich digestate Biogas is used as a renewable fuel to reduce the demand for brown energy Digestate is used in agriculture for the production of crops Waste from human and animal consumption creates more AD feedstock

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SOUTH AFRICAN MARKET

Bio2watt plants:

• BBP = 1st commercial scale AD plant in SA to export power to Eskom grid (Oct 2015) ;
• Fully commercial plant – with Financial Case based entirely on revenues from (a) feedstock gate

fees and (b) power sales to grid;

• Based on success of BBP plant, Bio2Watt are developing 2nd similar scale plant on large dairy

farm in Western Cape Province; construction commenced in 2016.

Key Benefits of AD to SA:

• Adds power to Eskom national grid;
• Moves country towards its renewable power targets;
• Moves country towards more sustainable waste management (including diversion of

biodegradable waste away from landfill disposal);

• Provides employment in rural areas of the country.

Potential Constraints / Challenges

• Process water availability;
• Bio-security;
• Limited current end use for surplus process CHP heat;
• SA planned programme of nuclear build (long-term).

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The Role of Anaerobic Digestion Technology in Treating Organic Waste – UK Experience

Presentation to GreenCape Networking event, 23rd August 2016

Andrew Street Director, SLR Consulting astreet@slrconsulting.com