Dewatering of biological slurry by using water‐absorbent polymer gel

Abstract

A new concentrating/dewatering process utilizing water‐absorbent polymer gels as dewatering media for biological slurries is proposed. The polymer gel applied to the process should be of porous structure for rapid water‐absorption and of larger size for easier separation of gel from slurry. Poly(vinylmethylether) gel (PVMEG) prepared by γ‐ray irradiation was found to be suitable for the purpose. PVMEG swelled or shrunk reversibly in response to temperature and its transition temperature was 310K. Slurries of different properties were dewatered quite well by applying PVMEG. The water‐absorbability of the gel was unaffected by the properties of organic substances contained in the slurries. An engineering calculation of the proposed dewatering process, which was called “gel dewatering process,” revealed that the process was promising for concentrating/dewatering microbe‐rich slurries in the respect that it would be composed of compact and simple apparatuses and be an energy saving system.