Effects of the Addition of Bamboo Charcoal 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 loading micro-organisms derived from activated sludge on the water purification ability of the phosphorus remover were investigated. In addition, the effects of adding bamboo charcoal as a carbon source to the phosphorus remover on the adherence of microorganisms and the organic matter removal capacity were examined. The phosphorus removal material was obtained by mixing gypsum, CaCO3 and bamboo charcoal in specified volume proportions. Microorganisms were loaded on the specimens by immersing them in activated sludge for 5 days. The microorganisms supported samples by immersing in activated sludge showed higher organic matter removal capacity than the non-microbial-supported sample. Furthermore, the bamboo charcoal-added samples were able to remove organic matter in a short time than the samples without bamboo charcoal. The phosphorus removal ratio of the sample after immersing in activated sludge was almost the same as that before immersion, but when the amount of bamboo charcoal added was excessive, the phosphorus removal ratio decreased drastically. This decrease in phosphorus removal ratio would be attributed to a decrease in the content of CaCO3, which acts as a crystallization site for calcium phosphate, and to the coating of CaCO3 exposed on the surface of the phosphorus remover by the adherence of a large amount of microorganisms due to the excessive addition of bamboo charcoal.