An energy consumption comparison of sewage treatment systems

摘要

In Japan, 72% of the population had access to sewage treatment in 2008. Collecting and treating sewage are energy intensive processes, so countermeasures to promote energy saving are necessary. Sewage sludge produced from wastewater treatment can be used as an effective energy source because it has the following four characteristics: its quantity and quality is more stable than other wastes; no new energy is needed to collect it in Japan, because the collection networks (sewage drainage and treatment plant) are already constructed; it is produced mainly in urban regions, where energy demand is strongest; and it has a lower heating value (LHV) of 16-19 MJ/kg of dry solids. Furthermore, sewage sludge can help reduce global warming because unlike fossil fuels, it is a carbon neutral material.