생물화공 , 에너지 / 환경 : Zeolite 를 적용한 활성슬러지 공정에서 잉여 슬러지내 포함된 Zeolite 재이용에 대한 가능성 평가 = Biochemical Engineering , Energy / Environment : An Evaluation for Zeolite Reuse from Excess Sludge in Zeolite Immobilized Activated Sludge Process

다국어 초록 (Multilingual Abstract)

A feasibility of zeolite reuse by thermal treatment of excess sludge in zeolite added activated sludge(AS) was evaluated. Optimal regeneration conditions for NH_4^+-N ion exchange property of zeolite in excess sludge was decided at 500℃ of temperature for 1h, which corresponded to 88% of regeneration efficiency. The reactor of zeolite dose, run in two models according to zeolite dosed(model Ⅰ-original zeolite dose and model Ⅱ-regenerated zeolite addition), was compared to conventional AS under equivalent operating condition. The concentration of zeolite in aerobic basin was maintained at 4,000㎎/l, and the average concentrations of COD, T-N and T-P in influent were 150㎎/l, 40㎎/l and 3㎎/l, respectively. Besides, influent NH_4^+-N concentration was increased from 40㎎/l to 90㎎/l and 135㎎/l, separately, in 88 d and 96 d of operating duration(model Ⅱ). Though the removal efficiency in soluble organic compounds was similarly observed between two reactors, the removal efficiency of total organic compounds in AS of zeolite addition was improved by 28%, compared to conventional AS. The result was attributed that zeolite progressed sludge settling property followed by enhancing SS(Suspended Solids) concentration from 2 to 12㎎/l in effluent. While, AS reactor with zeolite addition averagely showed high nitrification efficiencies of 74% and 76% in model Ⅰ and Ⅱ, respectively, although conventional AS averagely revealed only 58% of nitrification efficiency. As a consequence of evaluating a mutual relationship among nitrification rate, microbial concentration and nitrification efficiency, the enhancing nitrification in AS of zeolite dose was ascribed to high concentration of nitrifying bacteria. In addition, at 90㎎/l and 135㎎/l of increased NH_4^+-N concentration, the reactor with zeolite application showed 16 to 20% of nitrification efficiency higher than that in conventional AS, and hereby it was validated that nitrification of high activity was accomplished in AS with regenerated zeolite dose.