Effects of difference ph and concentration parameters on bacterial removal by ultrafiltration

Abstract

Ultrafiltration membranes technologies are finding increasing application in disinfection process to improve water quality for drinking water production as a safety and environmentally process. However the influence of water pH and bacterial Escherichia Coli (E.coli) concentration limited the applicability of this technology due to the fouling phenomena. The specific objectives for this study are to investigate the effect and the optimum value of Escherichia Coli concentration and pH parameters on the bacterium Escherichia Coli removal through the UF membrane. In this study three different water pH6, pH7 and pH8 and bacterial E.coli concentration log 105.1 cfu/ml, log105.7 cfu/ml and log 1o6 cfu/ml though to be in some extent responsible for membranes fouling are evaluated. Ultrafiltration membrane with difference composition made of polysulfone (PSF), N-metil-2-pyrolidone (NMP) and polyvinylpyrolidone (PVP)-(13wt.%, 15wt.% and l 7wt.%) using an electrically­ controlled casting machine are prepared. The membranes permeability and performance of removing E.coli in different feed concentration and pH were determined based on E.coli solution flux and rejection percentage. The ability rejection of different feed concentration for each membrane shown that the lower the bacterial solution concentration the higher the flux and bacterial rejection in the following manners: (log105.l cfu/ml > log105.7 cfu/ml > log106 cfu/ml). The pH adjustment could be used to control the UF fouling and bacterial rejection. The acid pH will improve the UF performance, where this behavior is explained in term of charge effects on membrane size. These finding suggested that the best membrane composition is I3wt.%, with log105.l cfu/ml solution concentration with pH 6. Besides, the higher percentage of bacterial E.coli rejection (7 log reduction value) showed a great potential of applying UF membrane in water treatment plant.