Effects of the Type of Micro-Organism on the Water Purification Ability of Micro-Organism Supported Crystallization Type Phosphorus Removal Materials

Abstract

In order to prevent water pollution in closed waters such as inner bays and lakes, it is essential to establish a method to remove phosphorus and organic substances which cause water pollution. We have tried to give organic substances removal ability to a crystallization type phosphorus remover composed of gypsum and CaCO3 by supporting useful microorganisms on the surface of the remover. In this study, the effects of types of microorganisms derived from activated sludge or culture solution on the water purification ability of the phosphorus remover supported with microorganisms were investigated. The porous phosphorus removal material was obtained from solidified gypsum containing NaCl by washing to dissolve the NaCl, silica coating and carbonating. The phosphorus removal material supported with micro-organisms by immersing in activated sludge showed high organic matter removal ability, and there was almost no change in phosphorus removal ability before and after the micro-organisms were supported. In contrast, when microorganisms were supported by immersing materials in culture solution, the phosphorus removal capacity was significantly lower than that before immersing in the culture solution. In addition, the removal capacity of organic substances was lower than that of the materials immersed in activated sludge. The decrease in phosphorus removal ability and low organic matter removal ability of the materials immersed in the culture solution are caused by the detachment of the silica coating layer and CaCO3 on the surface of the phosphorus removal material. Therefore, activated sludge as the type of microorganisms is more effective than culture solution to prepare the water purification material which has both the phosphorus removal and organic substances removal capabilities.