Abstract
A new generation of high gradient magnetic separation (HGMS) has recently received attention again, especially for its applications in the fields of water and wastewater treatment. The reason for this attention is that a newly developed superconducting magnet can be used to easily generate a high magnetic field, under which even weakly paramagnetic materials can be separated at high efficiency. Furthermore, new magnetic seeding processes without the addition of magnetite have been developed for the separation of nonmagnetic particles from the viewpoint of colloid chemistry and material science. We also have developed a new wastewater treatment process that uses magnetic gel particles containing immobilized microorganisms and magnetic particles. The magnetic gel particles are magnetically separated and recovered from the effluent in wastewater treatment processes, and are then recycled to a bioreactor directly or reused after storing. In this paper, the applications of magnetic separation to the recovery of microorganisms for wastewater treatment use were reviewed. Further, a novel type of magnetic separator without a filter matrix was introduced to the continuous separation and recovery of magnetic gel particles with different magnetic characteristics.
