REDUCTION OF BACTERIOPHAGE IN SURFACE WATER BY COAGULATION WITH CERAMIC MEMBRANE MICROFILTRATION

Abstract

The main objective of this study was examining the reduction of F-specific RNA bacteriophage Qβ from spiked-surface water by coagulation with ceramic membrane microfiltration. The effects of pore size of the ceramic membrane (0.1, 0.5 and 1.0 µm), coagulant dosages (1.5, 2.0, 2.5 and 3.0 mg-Al/L), and initial bacteriophage Qβ concentration (5.00E+05, 8.00E+06 และ 8.00E+07 PFU/mL) to the reduction of F-specific RNA bacteriophage Qβ were investigated. Bacteriophage Qβ was used as an indicator of human enteric viruses which a major cause of waterborne diseases. The reduction performance of Qβ was measured by overlay plaque assay and reported in plaque forming unit (PFU) method. In this study, water sample was collected from Ping River in December 2011 (Chiang Mai, Thailand), which contained turbidity of 41.77 NTU. Polyaluminium Chloride (PACl) was used as a coagulant in coagulation process. From the experiment results, the smaller pore size ceramic membrane, microfiltration yields higher bacteriophage Qβ log removal. When the coagulation was applied, coagulants dosage strongly affected bacteriophage Qβ removal. The high log removal (7.9) was achieved with 0.1 µm ceramic membrane pore size at 3.0 mg-Al/L PACl dosage, while 0.2 log removal was observed by ceramic membrane microfiltration alone. Furthermore bacteriophage Qβ concentrations in feed water affected the removal efficiency as well. The high initial Qβ concentration (8.00E+07 PFU/mL) was affected the reduction efficiency. It was required more amount of PACl dosage to form the large aggregate which larger than the pore size of 0.1 µm ceramic membrane microfiltration. At the highest PACl dosage coagulation(3.0 mg-Al/l) , 0.5 µm and 0.1 µm pore size achieved equivalent capability to reduce bacteriophage Qβ. Thus, the PACl coagulation with 0.5 µm ceramic membrane filtration was the achievable condition for reduce bacteriophage Qβ since it can produce in larger filtrated volume than 0.1 µm.