Lidón Herrera Prats, a final year master degree student at Universitat Jaume I (UJI), has conducted a study that shows biodrying is an effective alternative technique to produce energy from solid waste. She used greenhouse biodrying technology and force ventilated reactors for the study. Another innovation in her study was the use of garden waste instead of municipal waste.
The tests continue at the university facilities of INGRES-Engineering Group Waste
Biodrying is a process where the temperature of biodegradable materials increases due to microbial aerobic fermentation. Water in the solid waste is evaporated due to the temperature increase, which offers an efficient biofuel. Even the volume and weight of the waste are decreased, which in turn reduces the transport expenses to landfill.
Lidón Herrera constructed greenhouses using wooden pallets that were closed with wire meshes measuring 80x120 cm and also used 25 l of cylindrical tanks with four air vents as reactors. The research still continues at INGRES-Engineering Group Waste facilities of the university.
According to Herrera, the application of greenhouses and reactors for biodrying in institutions like the UJI that generate over 35,000 kg garden waste from trees, grasses and bushes, will save waste removal cost and enable electricity production with a biomass boiler that will give light to at least 12 moderately sized classrooms per year.
The paper concludes that both greenhouses and reactors are affordable drying methods for garden waste and the greenhouse method is more advantageous due to even heating of the material. This uniform heating is caused by the production of external heat from the sun and internal heat from the bacteria.
Through greenhouses, around 52% to 92% of moisture was reduced, 50% volume loss and 75 % weight reduction were observed, and in reactors around 60% volume and weight reduction were observed.