Abstract
A large amount of sludge is discharged from sewage treatment plants, and therefore efficient sludge management system is needed to cope with the growing amount of sewage sludge. Energy efficiency in sludge treatment system is one of the important aspects so as to pursue the sustainable sludge management system.
Tokyo metropolitan government has been promoting recycling of sewage sludge as its sludge management policy. In order to evaluate the Tokyo's sludge management policy, we think it significant to analyze the aspects of energy consumption of the current sludge treatment processes such as dewatering and incineration, along with recycling plants.
In the Tokyo area, however, complicated sludge treatment systems have been historically applied, and it was difficult to comprehensively grasp sludge flow and energy consumption in sludge treatment systems.
In this study, we calculated the energy consumption and CO2 emission of each unitprocess in existing sludge treatment system and recycling plants in Tokyo, by looking into actual and detailed flow of sludge, which was clarified from primary data and hearing to Tokyo metropolitan government. We also conducted a comparative analysis of energy consumption between three sludge-recycling plants, and then examined current status of sludgetreatment and recycling system in terms of energy consumption.
