고정화 활성슬러지를 이용한 시안화합물 분해에 관한 연구

Abstract

Cyanide is highly toxic to ecosystems, cyanide-containing effluents cannot be discharged without being subjected to treatment to reduce to very low levels (0.1 Many microorganisms have an inherent capacity to degrade the toxic organic compounds that enter the environment as a result of pollution and natural activities. However, there are few examples of biological degradation for cyanide compounds in the field. The immobilization of a microorganism has been rapidly progressed with the development of bio-technology and it has been used as a tool to isolate products from biological media in various areas, it has not yet been practiced in the treatment of wastewater. This study has been optimized operating conditions removal to cyanide in a synthetic wastewater by PEG method with microorganisms immobilized. The immobilized activated sludge utilized of Ni(CN)42- as a nitrogen source. During cyanide degradation, ammonia and carbon dioxide were found as final products. The utilization of ammonia formed by Ni(CN)42- degradation was investigated by adding the glucose as carbon source. In the batch experiments, the effects of a substrate concentration, pH, amount sludge, phenol, bead packing volume, glucose, thiocyanate on the removal of cyanide compounds were investigated a maximum condition by immobilized activated sludge. The higher degradation activity was obtained at pH 7.0. In case that pH was beside 6~9, relative activity was dramatically decreased. The cyanide degradation decreased with increasing of initial cyanide concentration. Although cyanide degradation increased with increasing of glucose, phenol and SCN- . In continuous experiments operational conditions is HRT 48~24hrs, pH 8.0, bead 30%. The hydraulic retention time of 36hr, the higher degradation efficiency of cyanide was shown. As decreasing the hydraulic retention time further down to 24hr, the degradation efficiency of cyanide degreased to 90%. The removal efficiency of cyanide were 99%, while HRT was 36hrs.