Removal of DOM and THM formation potential of tropical surface water by ceramic microfiltration

Abstract

Dissolved organic matter (DOM) and trihalomethane formation potential (THMFP) removal by ceramic microfiltration (CMF) under different operating conditions was investigated and compared with the performance of a conventional water treatment plant at Bangkhen, Thailand. The tropical surface raw water for all the experiments was taken from Chaophraya River, Bangkok, Thailand. CMF studies were conducted with both pilot scale (Pilot-CMF) and laboratory scale (Lab-CMF) units. Observations indicate that the properties of raw water such as dissolved organic carbon (DOC) concentration and specific ultraviolet absorbance (SUVA) vary with time. Under these varying raw water conditions, the conventional water treatment process demonstrates varying THMFP removals. The Pilot-CMF provides better and steady THMFP removals compared to conventional process. Bangkhen water treatment plant (BWTP) filtrate SUVA (2.01 ± 1.07) and Pilot-CMF filtrate SUVA (3.22 ± 0.98) were significantly lower compared to raw water SUVA (4.79 ± 1.39). This SUVA reduction indicated a higher removal of aromatic DOMs through both treatment processes. Pilot-CMF manifest a grater removal of hydrophilic DOM compared to filtrate from BWTP. This corresponds to a higher reduction of THMFP by Pilot-CMF over BWTP. It was found that higher removal of DOC by Pilot-CMF is associated with coagulation process, effects of suspended solids and membrane properties.