Digestate use in the UnitedKingdom

Clare T. Lukehurstand

Oliver Harwood

IEA Workshop 15 September Cork

Task 37 (UK)

Digestate in the UK context

• IEA Utilisation of Digestate brochure

• Current use of animal manure, bio-solids andother organic material as fertiliser

• Where it comes from and where used

• Current UK research

• Current UK regulations on use

• Methods of application – best practice

• Case study

• Reduced odour

• Veterinary safety

• Plant pathogen reduction

• Reduction of weed seeds

• BUT: take care! AVOID

• Chemical contaminants

• Biological contaminants

• Physical contaminants

Organic fertilisers from AD

On farm + food

Off farm food, ABP etcOn farm + energy crops

On farm manureOn farm mixed waste

Food processors

Sewage sludgeonly

Sewage sludge +source separatedMSW

Organic fertiliser use on UK farms2008 (76m tonnes) (69% farms)

Farms not usingmanure, etc

31% Poultry (layer &broiler

5%

Cattle FYM 55% Other FYM 1%

Cattle slurry 18% Imported fromother farms

2%

Pig FYM 3% Biosolids(sewage cake)

2%

Pig slurry 1% Other non farm 1%

Source: Defra (2009)The British Survey of Fertiliser Practice 2008

Imports from farm and non- farmsources

(million tonnes /yr)

Cattle FYM 0.7 Poultry(broiler)

0.2

Cattle slurry 0.1 Other FYM 0.0

Pig FYM &slurry

0.6 Other FYM 0.1

Poultry (layer) 0.6 Other non-farm

5.4

Source: Defra (2009) op.cit

Application of cattle slurry( % of farms)

Farm type Broad-

cast

Band

spread

Injection Other

Cereals - - - -

General cropping 70 25 25 0

Dairy 90 8 9 4

Other livestock 89 9 2 1

Pigs & poultry - - - -

Mixed 84 6 2 0

Pig manure 96 - - 4

Source: Defra (2009) op cit

Biogas plants in the UK

Type of plant Number Capacity

Farm and Food 65 51 Mw

Sewage sludge 146 189.2 Mw

Landfill 1054.6 MwSource: Decc Statistics 2011 & WRAP

Estimating the tonnage of digestate

For farm and food based plants:

•Assume gas yield ave 350m3/T• Assume 2million m3 required perMW installed• 51MW farm and food digesterswill use roughly 300,000T input –but wide range of feedstocksmean this is an estimate only.

Best guess: about 300,000T farm digestate(plus a further million tonnes from the sewage industry)

currently in use

Organic fertiliser used on crop and grass(% of land) in 2001 and estimated for 2010

2001 Animalmanure43% of allgrass

200119% used

mainly on foragecrops

201036% digestateused on grassland57% digestateon combinablecrops, forage,energy maize &vegetables

Sources: Defra (2002) British Survey of Fertiliser PracticeData provided by farmers & AD plants 2010

Field Experiments – Digestate inAgriculture

• ‘To quantify the effects ofcontrasting digestate and compostapplications on soil and cropquality, crop available nitrogensupply and emissions to the airand water environments’

• 2010 – 2014 this joint WRAP /Defra initiative is investigating:– Soil quality

– Agronomic benefits

– Crop quality / yield

– Crop safety

– GHG impacts

Confidence in digestate?

• Responding to concernsof UK farm assuranceand retailers

• Critical literature reviews– Allergens

– Flavour / odour taints

– Clostridium

– Persistent herbicides

• Risk assessment

• Digestate data

• Digestate stability / odour

David.Tompkins@wrap.org.uk

Two regimes: Environment Agency (Wasteregulations Standard Rules (SR)) and AnimalHealth (Animal By Products Regulations (ABPR))

• No imports of ABP + SR16 = no spreading licence• Import of manure for AD requires pasteurisation under

ABPR but under SR 16 = no spreading licence• Any other case requires ABPR compliance plus full

waste permit and transfer approval and spreadingpermit unless

• AD plant registered and compliant with Biofertilisercertification scheme” – in which case no spreadinglicence as digestate is no longer a waste.

Digestate Regulations for farmers

Environment Agency on farmstandard permit SR16

Table 2.3 Waste Types permitted

Waste CodeDescription

02 WASTES FROM AGRICULTURE, HORTICULTURE, AQUACULTURE, FORESTRY, HUNTING AND FISHING,FOOD PREPARATION AND PROCESSING

02 01 wastes from agriculture, horticulture, aquaculture, forestry, hunting and fishing

02 01 01 sludges from washing and cleaning − food processing waste, food washing waste

02 01 03 plant tissue waste - husks, cereal dust, waste animal feeds, off-cuts from vegetable and fruit and other vegetation waste

02 01 06 animal faeces, urine, manure including spoiled straw

02 05 wastes from the dairy products industry

02 05 01 biodegradable materials unsuitable for consumption or processing (other than those containing dangerous substances) −solid and liquid dairy products, milk, food processing wastes, yoghurt, whey

02 05 02 sludges from on-site effluent treatment

Plus, of course, non waste feedstock such as purpose grown crops

Spreading “waste”

• Unless exempt (T16) or treated to becomebiofertiliser all digestate is a waste.

• Producers must only transport with waste carrierlicenses

• Must only be spread subject to site licenseswhich are limited to 50ha blocks.

• Environment Agency charges fees and red tapeimposes delays when issuing spreadinglicences.

Regulations for PAS110 Certification

• Covered by “Biofertiliser certification scheme”

• Feedstock must be from source separated origin(no mixed waste)

• AD must include full pasteurisation and testing ofdigestate

• Independent assurance of product quality.

• Details at www.biofertiliser.org.uk/

Liquids whole or separated: 26% use trailing shoes orinjection, 20% broadcast (Splash plate) others 5%.

Separated solids (farms) : Broadcast 31%WWT bio-solids 97% broadcast 3% otherNo of respondents: 25 ( 63% of known plants)

Some farms used more than one method

Avoiding waste of N

Source: IEA Digestate Brochure

BUT Already applied nutrients from his own manure14.16 10.0 20.0

Saved purchase of 45.84 All All£ saving expenditure for N £31,171Offset by extra spreading cost of £9,000

Net savings of £22,171 + opportunity to sell surplus P

Crop need NH 4 -N P2O5 K2 OTonnes 81.98 41.27 50.16Digestate (t)` 60.00 53.13 105.72

Case study

Organisations supporting theUK membership of the IEA

Sponsors:Agri-food and Biosciences Institute (Northern Ireland), Biogen (UK) Ltd, BiogasNord UK Ltd, BiogenGreenfinch Ltd, Bioplex Technologies Ltd,Chesterfield Biogas Ltd, CNG Services Ltd, Country Land and BusinessAssociation (CLA), GWE Biogas, Hardstaff Group, J.H. Walter SustainableResource Management, Masstock Smart Farming, Methanogen UK Ltd, NationalGrid , Natural England, NETZSCH Pumps Ltd, Omex Environmental ServicesLtd, Peter Jones OBE, Organic Power Ltd, Royal Institution of CharteredSurveyors, Renewables East, Summerleaze Ltd, Sustraco Ltd, The AndersonCentre, University of Southampton, UTS Biogas Ltd, Veolia EnvironmentalServices Ltd, Xebec Adsorption UK Ltd, Xergi UK Ltd, The Esmee FairbairnFoundation and

supported by DEFRA, DECC and DfT