Using Horizontal Roughing Filter as an Effective Post-Treatment System for Palm Oil Mill Effluent (POME): Effect of Media Sizes and Filtration Rates

In this study, palm oil mill effluent (POME) from polishing pond of palm oil mill treatment plants has been chosen to be treated in laboratory experiment using horizontal roughing (HRF) filter system. The purpose of this article was to evaluate the effect of three filter media sizes on the removals of COD, NH3-N and turbidity and as well as to evaluate the effect of three filtration rates on the removal of color, turbidity and suspended solid from POME using limestone media in HRF system. The results indicated that the removal of smaller filter media gave higher removal efficiency and larger size of filter media gave lower removal efficiency. Optimum removal of COD, NH3-N and turbidity were 27%, 51% and 32%, respectively, which were obtained at lowest filter media size (i.e. 3-6 mm). Similar result was also obtained in studying the effect of filtration rates. It was found that the optimum reduction of turbidity, suspended solid and color were up to 38.6%, 57.4%, and 34.5%, respectively, at lowest filtration rates of 0.3 m h-1. These results were supported by one-way analysis of variance (ANOVA).