Removal of dissolved organic matters and bacteriophages in natural water by in-line coagulation combined with ceramic membrane

Abstract

The main objectives of this study were to evaluate Dissolved Organic Matter (DOM) surrogate parameters (DOC, UV-254, and SUVA) removal, DOM characterization and DOM removal by FEEM, THMFP removal, and correlation between THMFP and DOM surrogate parameters from raw water and filtrated water by In-line coagulation combined with ceramic membrane. Water samples were collected from Ping River and Ang Keaw Reservoir. In-line coagulation using Polyaluminium Chloride (PACl) as coagulant was induced to be pretreatment of ceramic membrane filtration. According to the DOM surrogate parameters removal results, In-line coagulation with PACl dose of 2.5 mg/lAl combined with UF was the optimal condition for DOM removal in Ping River water while In-line coagulation with PACl dose of 3.0 mg/lAl combined with UF was the most achievable condition for DOM removal in Ang Keaw reservoir water,. However, the keys to select the appropriate membrane pore size for practical operation were the filtrate quality and filtrate quantity that depend up on the utilizable purpose. Therefore, In-line coagulation combined with MF was the alternatives to UF in order to produce high flow rate filtration. The suitable DOM surrogate parameters that could be used to predict the quantity of THMFP in Ping River water and Ang Keaw Reservoir water were DOC and UV-254. This study also interested on the microbial indicators to evaluate the filtrated water quality from this treatment applicability. Total coliform and E. coli were used as indicator for determining the fecal pollution reduction in this experiment. Total coliform and E. coli were found from Ping River water in amount of 75 CFU/ml and 4 CFU/ml, respectively and from Ang Keaw Reservoir water in amount of 500 CFU/ml and 40 CFU/ml, respectively. From the results obtained from both of two raw water sources, 1.0µm ceramic membrane and In-line coagulation combined with 1.0µm ceramic membrane could fairly remove total coliform while MF/UF ceramic membrane and In-line coagulation combined with MF/UF ceramic membrane could remove total coliform and E. coli completely.