Anaerobic Digestion

Kedco is currently working with two leading technology providers of dry fermentation and wet fermentation technologies. Both suppliers are the leaders in their areas with there technologies proven having numerous sites operational throughout Europe

Our solutions can use an array of feedstock - municipal, food industry or agricultural waste.

Depending on the type of organic matter utilised, our solutions can process 60,000 tonnes of organic matter per annum and produce between 2MW and 4MW of electricity.

Anaerobic digestion is a series of processes in which micro-organisms break down biodegradable material in the absence of oxygen. This process utilises renewable resources as a feedstock to produce a methane and carbon dioxide rich biogas suitable for energy production. The nutrient-rich solids left after digestion can be used as fertiliser and compost.

Emission of greenhouse gases are reduced by the anaerobic digestion process in a number of ways including replacement of fossil fuels, reduction of landfill methane emissions, displacing chemical fertilisers and reducing vehicle movements.

Power generation via anaerobic digestion is eligible for ROCs.

Almost any organic material can be processed with anaerobic digestion. This includes biodegradable waste materials such as waste paper, grass clippings, leftover food, sewage and animal waste. The plants comprise, inter alia, a number of digesters and CHP plants.

Organic material is received at the plant and fed, in batches, into the digesters. A typical digester is a 770 cubic metre concrete chamber with an airtight door. The digesters are then sealed and the organic matter heated to a temperature of 408C. The interior of the digester is sprayed with a water vapour containing micro-organisms. The micro-organisms feed upon the organic matter converting it, via a number of chemical stages, into biogas. The biogas is piped from the digester into a CHP plant which then converts it into heat and electricity. The final stage of the process involves transferring the electricity from the CHP unit to the electricity grid.

A digester is typically sealed for approximately 28 days during which time biogas is produced. At the end of 28 days, the digester is opened, the residual organic matter removed and a new batch of organic matter introduced.