LAKE WATER TREATMENT FOR DRINKING USING CERAMIC ULTRAFILTRATION MEMBRANE SYSTEM WITH PERIODIC WATER-BACKFLUSHING

摘要

Many researchers have published the results of wastewater treatment by membrane separation. Tchobanoglous et al. [1] treated highly the domestic wastewater by ultrafiltration (UF), and Roorda et al. [2] investigated the characteristics of UF for effluents of two wastewater treatment plants. As an example of applications of ceramic membranes used in this study Li et al. [3] used ceramic MF membranes to separate cells from E. coli-containing fermentation broth. However, the economic efficiency of membrane separation for wastewater treatment should depend on the power cost of operation, the permeate flux, and the membrane lifetime. The lifetime of membranes has a deep relation with membrane fouling during the operation. It was well known that the membrane fouling was made by concentration polarization and gel layer formation on the surface of membranes, and adsorption and pore blockage in the pores inside membranes. Therefore, a lot of researches have been accomplished for solving the membrane fouling in the world. Then, the membrane backflushing is a new technology to minimize the membrane fouling, and to maintain a high permeate flux during membrane separation. Many papers related with membrane backflushing have been published nowadays. Davis et al. [4] built up a modeling of concentration and depolarization with high frequency backpulsing. And Kuberkar et al. [5] could reduce the fouling resistance of pollutant layer on the membrane by backflushing in the microfiltration of protein cell mixture (BSA, yeast). Then, we published membrane fouling control effects of periodic water-backflushing period, TMP, and flow rate using tubular carbon ceramic UF and MF membranes for recycling paper wastewater [6]. Also, we recently reported effects of periodic N2-backflushing in paper wastewater treatment using carbon UF and MF membranes [7].