Developement of phosphorus removal process to prevent water area from eutrophication has been carried out by many workers.
Among conventional methods, flocculation and sedimentation process has been employed widely. This process, however, produces large amounts of sludge and has many problems in the treatment of sludge.
Therefore we have investigated and developed the phosphorus removal process employing crystallization, which can minimize the amounts of sludge.
Application of this process to various wastewaters were studied by using laboratory and pilot scale plants.
The results are summarized as followed.
In case of application to sewage and night soil with pilot plants, this process demonstrated excellent performance and sludge production was less than one fifth compared with flocculation and sedimentation process by alum.