Wastewater sludge fuel system
Outline
Wastewater sludge is excellent when it comes to clustering and stable properties. Using the carbide (made from the sludge) for mixed combustion at coal-based thermal power plants, will contribute to mitigating the effects of global warming while recycling wastewater sludge in a stable manner for a long time. The wastewater sludge fuel system was developed through a joint R&D effort undertaken by Electric Power Development Co., Tsukishima Kikai Co., Ltd., J-PEC Co., Japan Sewage Works Agency and METAWATER.
Features
By carbonizing wastewater sludge at a low temperature of 250-500°C, it is recovered as a fuel substance with a calorific value that is sufficient for use as a coal substitute.
Through improvements such as the granular formation of dehydrated sludge and the addition of steam within the carbonization equipment, a number of effects can be achieved, including the safety of the fuel (control of self-heating), improved handling, and control of odor coming from sludge.
Adopting a lower temperature for carbonization to replace conventional high-temperature carbonization means that the generation of N2O is reduced. Also, using it in a power generation plant as an alternative to coal will significantly decrease CO2 emissions produced by fossil fuels since the fuel obtained from wastewater sludge is a carbon-neutral product.
Other low-temperature carbonization technologies
In addition to use for fuel conversion, another technology was developed. This technology, through low-temperature carbonization, can efficiently concentrate the water-soluble phosphate contained in the wastewater sludge for use as a raw material for producing phosphate fertilizer.
