to read the full report - Ecolateral by Peter Jones

Evaluation of Opportunities for Converting Indigenous UK Wastes to Wastes and Energy
AEA/ED45551/Issue 1
• The AD site at Bank Farm in Wales was one of the first on farm AD sites in the UK, becoming
operational in 1991 with a capacity to treat 790m 3 . It has recently been converted to generate
electricity from the methane produced on site.
A proposed AD site at Piddlehinton in Dorset has recently been granted panning permission. It is
expected that this site will accept 35,000 tonnes per annum of food waste, green waste and pig slurry,
and generate electricity and a biofertiliser. 255
Further sites that are fully consented but are not yet operational are Eye Airfield in Suffolk which is
expected to have an output of 1.05 MW, Dimmer in Somerset anticipated to have a 3MW output, and
Lowe Farm with a predicted output of 0.5MW.
International Situation
Digestion of agricultural manure and slurries by controlled AD are well utilised in some European
Countries. Centralised Anaerobic Digestion was first used in Denmark in the late 1980s. Its appeal is
growing rapidly and its use is now common in Germany and to some extent in Sweden and Italy.
Production of biogas in the EU 27 has risen steadily over the last few years and totalled 62 TWh in 2006
(once again, compare this against Drax power station output of 25TWh p.a.). 256
It is worth noting that the use of AD systems across Europe can be split into two distinct types. Southern
countries such as Italy, Portugal and Spain use it as a waste-water treatment technology because the
waste is collected at high water content levels, so containing low solid residues. While in northern
European countries such as Germany, Denmark and Switzerland the water content is considerably lower,
the solid content correspondingly higher and the systems optimized for fertilizer production. 257
Denmark
There are over 20 centralised plants operating in Denmark, with a further 20 farm scale operations.
Feedstocks are mainly pig and cattle manure, but also include waste food, fat sludge and brewery
wastes. 257
• The Vester Hjermitslev was the first centralized co-digestion plant in Denmark, built in 1984 and
supplied by 5 cattle and pig farms which supply slurry to the plant, together with a small amount
of fish processing waste, tannery waste and waste fodder. The process operates at 37°C, with a
sanitation stage of 4½ hours at 57°C. Once this is completed the biogas can be utilised in the
onsite CHP unit in the 2 motors (840 kW +770 kW). Any overproduction is used in a gas boiler
(250 kW). 257
• The Ribe Biogas Plant began operating in 1990 and is supplied by 69 livestock farms (cattle, pig,
poultry, mink), together with waste from abattoirs, food and fish waste. The facility is owned by
the supplying farmers, a food processing company that supplies organic waste to the plant, the
regional power company and two investment companies. The site operates at a digestion
temperature of 53°C, and the minimum retention time of 4 hours ensures the digestate is
sanitised, and is then used by the slurry providers as a liquid fertiliser, or sold as surplus. The
biogas produced by the system is piped to a CHP pant at Ribe, which generates electricity and
heat for the city using a mix of bio gas and natural gas. 257
• Nysted biogas plant was built as an extension to the already established Hashøj biogas plant.
Slurry and manure is received from 36 farms and is mixed with waste from the sugar industry, the
medicinal industry, tanneries, an abattoir as well as fruit and vegetable waste and held at 38°C,
with a sanitation phase consisting of 8 hours at 55°C. The plant is also able to process source
separated household waste. The biogas produced is used in a 2300 kW engine to generate
electricity for the grid and heat for 150 customers. 257
255 Green Light for £5.5 Million Dorset AD Facility, 16.03.09, LetsRecycle.com,
http://www.letsrecycle.com/do/ecco.py/view_item?listid=37&listcatid=217&listitemid=31237
256 Danish Centralised Biogas Plants – Plant Descriptions, Bioenergy Department, University of Southern Denmark, 2000.
257 Environmental Aspects of Biogas Technology, B. Klingler, German Biogas Association, AD-NETT.
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