| Summary: | 碩士 === 東海大學 === 環境科學系 === 88 === Water reuse becomes an important issue in recent years, owing to the insufficient water supply and high cost for water purification. However, how to develop a stable and economic treatment unit is a keypoint to decide the feasibility on water reuse. In this research, two operation systems such as an up-flow biofilter and submerged membrane bioreactor (SMBR) were performed to recover the municipal sewage wastewater, respectively, for the purpose of water reuse. Generally speaking, biofilter has the advantages including high treatment efficiency, easy operation and low cost on water recycling. And, SMBR was developed to improve the performance of activated sludge method. Therefore, the results obtained from biofilter and SMBR on water reuse was also studied in this reaeach.
As the biofilter was carried out for water reuse, the experimental result indicated that the biofilter was available in reducing the pollutants containing in municipal sewage wastewater. During the reaction time of 250 days, it was found that the biofilter could reduce the concentration of biochemical oxygen demand (BOD5) in influent from 27.1 mg/L to 3.0 mg/L in effluent. Similarly, the turbidity in influent, 14.2 NTU, could be reduced to lower than 1.2 NTU in effluent. In terms of other pollutants such an ammonia nitrogen, chemical oxygen demand (COD) and total coliforms, the result is significantly positive as well as BOD and turbidity reduction. In addition, the effects on flow rate in biofilter was insignificant, i.e., this biofilter system research could be used in different flow rates since the objective of water reuse was achieved.
As the SMBR system was operated in this research, the experimental result revealed that this process was remarkably suitable applied in water reuse, even though the influent contained high or low concentration of pollutants. After fifty-day operation, the concentration of BOD in effluent was reduced to below 1.9 mg/L, and the concentration of turbidity was reduced below 0.14 NTU.
The water quality of the effluent treated by biofilter and SMBR systems, respectively, meets the standards for water reuse; meanwhile, it functions well as simplifying the operation maintenance and management. It is concluded that these two systems have the feasibility in water reuse.
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