Basic research on activated sludge method for high-concentration salt

Abstract

Sewage treatment plants are often constructed near the coast to collect sewage by gravity flow system. However, powerful and large-scale typhoons have become frequent due to recent climate change, and there is a rising concern that the sewage treatment plants located near the coast will be flooded by seawater. Furthermore, there is potential risk of continuous seawater inflow if the inlet pipe is damaged by the earthquake. It has been reported that high salt concentration reduces the treatment function of activated sludge, and it is required to assess the influence and countermeasures of high salt concentration on the treatment performance. The authors conducted an experimental study on the treatment performance of activated sludge with and without salt acclimation, and confirmed that the function of removing organic matter was ensured by acclimatization up to a salinity of 2.0%.