New plasma reactor solves manure problem
Environmental concerns around the high levels of phosphorus and nitrogen in animal manure has led to EU regulations restricting its use as a fertiliser. The large quantities of animal manure that would have previously been spread on to fields must now be processed using an environmentally friendly technology. The EU-funded PLAGASMIC (Advanced microwave plasma gasification of pig and cow manure for cost-effective biogas generation) project developed and tested a microwave plasma reactor for this purpose. The aim was to convert manure into useful end-products at a low energy cost. Researchers produced a prototype microwave plasma reactor that uses multiple microwave sources to gasify animal manure. The continuous reactor makes use of low-energy microwave sources and produces syngas (a type of biogas with high hydrogen content). Microwave heating offers greater flexibility and control over traditional methods of heating. This is because of the reduced thermal lag, which means rapid heating and cooling rates can be achieved, resulting in improvements in rate, yield and product selectivity. An electrocoagulation filtration system was incorporated into the reactor to remove waste products from the remaining liquid after gasification. This resulted in 0.95 litres of pure water per litre of manure, as well as purified phosphate and nitrate salts for use in other applications. One reactor will be capable of treating up to 300 000 litres of manure per year and is suitable for a farm with less than 500 head of livestock. Groups of small farmers will be able to buy a system between them and move the unit from one farm to another when required. The PLAGASMIC reactor is set to provide a fast, efficient and low-cost solution for the disposal of manure. This will allow EU farmers to adhere to recent legislative changes while creating a new value stream for animal waste.
