Resourceful Earth Ltd is evolving.
Composting alone produces a sustainable, high quality horticultural and agricultural product using green (or botanical) waste that would otherwise be destined for landfill (with all its associated environmental issues). However we can do better…
The next evolutionary step on from composting is Anaerobic Digestion (AD). Through AD every part of the composting process can utilise resources previously untapped by traditional composting facilities.
Resourceful Earth is working to develop a new AD facility on its composting site that will not only divert green and food waste from landfill and create a valuable compost product, but will also generate green electricity from the anaerobic process.
A by-product of the composting process is gas, or gases to be precise. The main gas produced during composting is carbon dioxide, however this is only half the story. Aerobic composting is just that, aerobic, or with the inclusion of air (oxygen), however if the compost is not regularly aerated then the compost becomes anaerobic (without oxygen). Composting in anaerobic conditions changes the main type of gas produced from carbon dioxide to a far more potent greenhouse gas, methane. However, when harnessed, methane becomes a valuable source of sustainable electricity… a resource rather than a problem.
AD takes place without air in sealed ‘negative pressure’ chambers, as opposed to outdoors as with traditional composting. The AD system is completely controllable and odourless to the wider environment (due to negative pressure within the chambers).
The plant will produce 17,000 MWh of electricity per year. Ofgem gives UK household electricity consumption as 3.3 MWhr per year, which is therefore 5,151 households’ worth. Keynsham had 6,545 households in the 2001 census, so we will generate electricity for 79% of the households in Keynsham.
The plant will also produce a similar amount of heat per year. Ofgem gives UK heat consumption at 16.5 MWh per year, which means the site will produce enough heat to heat 1,030 households.
Digestate is a sustainable replacement to current widespread chemical fertilisers. In addition to the nutritional value digestate provides it is also a great soil improver due to the high organic matter it contains. This organic matter acts not only as a fertiliser but improves drainage and structure to soils. The benefits of digestate use in agriculture can be found on the WRAP website, click here for further information.
It is this sustainable energy resource and organic fertiliser production that makes Anaerobic Digestion such a visionary and vital step.
We feel so passionately about the use of Waste as a Resource that we are also building an Education Centre alongside the AD facility to help inform a wider audience about the benefits of Anaerobic Digestion in not only easing landfill pressure but also tackling food waste issues, improving green energy supply and sustainable fertiliser use.