MBR과 TiO2 광촉매 산화반응을 이용한 폐수의 고도처리에 관한 연구

Abstract

Advanced Treatment of Wastewater Using MBR and TiO2 Photocatalyst Oxidation Reaction

Roh Sung-Hee Advisor : Prof. Kim Sun-Il Ph. D. Department of Chemical Engineering, Graduate School of Chosun University

In this research, MBR and TiO2 photocatalyst oxidation reaction have been used for advanced treatment of wastewater for reuse. Membrane separation instead of precipitation tank was used for removing suspended solids, and they were removed completely using the developed MBR process. The removal efficiencies of total nitrogen and phosphorous were low, and the permeate flux decreased with time due to fouling of the membrane. Therefore, we developed cell immobilization support carrier using waste lime to enhance nutrients removal efficiencies and to reduce membrane fouling. The effects of immobilized support carrier volume fraction and aeration rate on the membrane separation and nutrients removal efficiencies have been studied. When TiO2 powder was used as a photocatalyst, it has to be recovered from water. Therefore, TiO2 coating process on support carrier with sol-gel method was proposed and photo degradation rate was measure. The support carrier developed in this research is porous one whose surface is rough enough to immobilize cells. As the aeration rate and support carrier volume fraction are increased, the membrane separation efficiency was increased. Total nitrogen removal efficiency was increased with increased effective MLSS concentration and effective SRT. Anoxic conditions of the inner support carrier enhance nitrogen and phosphorous removal efficiencies and also increased the phosphorous adsorption on waste lime support carrier. The removal efficiency of CODcr by photocatalytic degradation of humic acid was 85%. The powder recovery problems of TiO2 powder process were solved with TiO2 coating of support carrier process. From this research, it was found that the membrane coupled with fixed phase biofilm reactor is an effective wastewater treatment system to enhance membrane separation and nutrients removal efficiencies. Using TiO2 coating on the surface of support carrier, TiO2 powder recovery problem was completely solved and nonbiodegradable organic waste was removed. The process developed in this research can be used for practical wastewater treatment system.