Application of tubular ceramic membranes for reuse of wastewater from buildings

This research investigated the possibility of applying ceramic membranes fo r simple and compact treatment to reuse wastewater generated from hotel bui ldings for secondary purposes such as toilet flushing water. The tested mem branes were ultrafiltration (UF) and microfiltration (MIF) membranes of 15 kDa, 300 kDa, and 0.1 mm. Parameters such as transmembrane pressure, crossf low velocity, MWCO/pore size were changed and the performance of the membra nes and the quality of the permeate observed. Since the average particle size of the influent wastewater was 2.18 pm, lar ger than the pore size of the membranes tested, the effect of MWCO/pore siz e on the filtration performance plas marginal. When a pseudo-steady state w as reached, permeate flux increased with increased crossflow velocity. Furt hermore, it was better to adopt turbulent flow (Re>20,000) rather than lami nar flow in order to maintain constant transmembrane pressure and system st ability. The optimum transmembrane pressure was found to be 150 kPa; a higher pressu re will density the cake layer unnecessarily on the membrane surface which will induce quicker membrane fouling. When energy consumption was compared, MF with: 0.1 Gun, which was capable o f producing higher permeate flux in the initial phase of experimentation th an other tested membranes, was found to be the least energy consuming; the effect of other parameters besides the pore size of the membrane was neglig ible on the energy efficiency. The quality of permeates obtained from all the experiments investigated in this research satisfied the guidelines set by the Korea Ministry of Environ ment for the reuse of wastewater for secondary applications such as in toil et flushing water. (C) 1998 Published by Elsevier Science Ltd. All rights r eserved.