EXPERIMENT AND APPLICATION OF MEMBRANE TECHNOLOGY IN TIANJIN WATER RECLAMATION PROJETS, CHINA

摘要

Water shortage has become one of the most rigorous problems in the 21~st century in northern China. Recently, some new measures, which include utilization of treated wastewater as a complement water source, have been taken into consideration to solve this problem. Considering the strong public concern on reclaimed water quality and current technology available, microfiltration (MF) and reverse osmosis (RO), as membrane technology, have been introduced to treat secondary effluent in China. In year of 2001, two pilot tests were carried out in Tianjin City. One test employed conventional process and MF process with ozone oxidation to treat secondary effluent of Jizhuangzi Wastewater Treatment Plant (WWTP). The removal results of conventional process is better than that of membrane process if influent COD and SS are relatively higher, while the membrane process achieves excellent results and the removal of SS, turbidity, E. coli and bacteria can be considerably improved if influent COD and SS are lower. The other test introduced MF and RO process to treat effluent of Tianjin Economy Development Area (TEDA) WWTP, and the results showed that MF can be an excellent pretreatment for RO process, with total removal of 96.8% SS, 96.5% TDS, and 96.8% hardness. Based on pilot testing results, two full-scale Water Reclaimation Plants (WRPs) have been built up, located at TEDA WWTP and Jizhuangzi WWTP with capacity of 30,000 m~3/day and 50,000 m~3/day respectively. The operation results of the two WRPs have shown that the membrane technology is suitable to local sewage effluent and the reclaimed water can meet the water quality standard.