Effect of Surface Microstructure on Organic Matter Removal Ability of Microorganism-Supported Sintered Alumina Body

Abstract

The effect of the surface microstructure on the organic matter removal ability of the microorganism-supported alumina sintered body was investigated. Porous alumina body having various pore sizes and pore volumes were prepared by changing the amount of pore-forming agents having different particle sizes. Furthermore, the effect of the firing temperature on the microstructure of alumina sintered body, was investigated. The microorganisms were supported on the sintered alumina body by immersing the sintered alumina body in a culture solution containing yeast, lactic acid bacteria, and natto bacteria for 5 days. Regarding the organic matter removal ability of the microorganism-supported sintered alumina body, the change in the COD decreasing ratio after immersion in model sewage which was prepared with glycine and glucose having an initial COD value of 180 ppm, for a predetermined time, was examined. The COD decreasing ratio was less affected by the pore size of the sintered alumina body, but, increased as the pore volume increased. When the firing temperature is low, due to poor densification of alumina, a lot of voids are formed between the alumina particles, resulting in surface undulations that is advantageous for the adhesion of microorganisms. As a result, the organic matter removal ability of the sintered alumina body fired at a low temperature tends to be higher than that of the sintered alumina body fired at a higher temperature. In order to improve the organic matter removal ability of the sintered body in which the pore-forming agent is added only to the upper surface of the sample, the porous layer formed by the pores formed by the pore-forming agent needs to have a thickness of above 0.01 cm.