| Summary: | 碩士 === 國立臺灣大學 === 生物產業機電工程學研究所 === 93 === In order to improve the performance of the treatment plant and reduce its operating cost, the Entrapped Mixed Microbial Cell (EMMC) reactors were utilized to treat the secondary effluent of the coking process in this study. The
effects of the hydraulic retention time (HRT) and the packing ratio on the treatment efficiency were evaluated.
Temperature was controlled at 30±1°C during the whole experiment. Operation of the EMMC reactors were started with an HRT of 24 hrs, and followed with 12, 8, 6, 4, 2 and 1 hrs of HRT’s. Two different packing ratios, 35% and 20%, were also tested to assess the efficiency of the EMMC reactors. Also, the biodegradability of the secondary effluent VC-757 was examined using the activated sludge (VC-756). Besides, reactivation of the EMMC was conducted after series of reducing HRT tests. The concentrated raw wastewater (VC-703) was used as feed in the reactivation experiment.
Results showed that, at the operational condition of 35% packing ratio and 12 hrs HRT, the optimal SCOD removal efficiency of 23% was achieved. The highest TCOD removal efficiency of 52% was achieved at 20% packing ratio and 8 hrs HRT, while the highest TCOD removal efficiency of 93% was observed at 35% packing ratio and 8 hrs HRT. Additionally, when comparing the organic loading, more than 50% of TCOD removal efficiency could be achieved at 63 mg TCOD/L/hr (at the test of HRT 8hrs), and more than 20% of SCOD removal efficiency was observed at organic loading of 24 mg SCOD/L/hr (HRT 12 hrs). For the biodegradability test of the feed VC-757, after 12 day’s treatment with 4:1 mixture of activated sludge (VC-756) and VC-757, SCOD was observed at the lowest concentration of 479 mg/L. Therefore, the biodegradability of the feed (VC-757) was estimated about 18%. In the reactivation test, after feeding with 1:1 of raw wastewater VC-703 and the secondary effluent VC-757, the TCOD removal efficiency was remarkably improved to 68%, and the SCOD removal efficiency was improved to 73%. Accordingly, 78% of the theoretical SCOD removal efficiency could be estimated for treatment of VC-757 using EMMC.
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