Performance of the sludge thickening and reduction at various factors in a pilot-scale MBR

In this study, the performance of a sludge thickening and reduction system coupled with filtration using a flat-sheet membrane was investigated. The effects of various factors such as HRT, flux and addition of coagulant were determined. TMP was observed to increase as the HRT decreases and the operating flux increases. The operating condition was then determined and the selected HRT and flux were 6.7 days and 10.7 L/m2 h, respectively. Different operating HRT indicated the variation of hydraulic loading rates for the organics and other nutrients affecting membrane fouling, while varying the flux showed the rate of decrease of the membrane permeability. When coagulant was added, the rate of increase of TMP was decreased, allowing the system to be operated for a longer period of time. It was observed that inorganic coagulant was more effective than organic coagulant based on the final TMP. It also suggests that membrane fouling was better minimized with the addition of inorganic coagulant. It was found that the most essential factor on membrane fouling was the addition of coagulant, while the effect of HRT was observed to be the least influential among the other factors considered.

Change in TMP at constant flux under a long term operation.Figure optionsDownload as PowerPoint slideHighlights
► TMP was observed to increase as the HRT decreases and the operating flux increases.
► The rate of increase of TMP was decreased with the addition of coagulant.
► Inorganic coagulant was more effective than organic coagulant based on the final TMP.
► Application of membrane filtration coupled with coagulation was proven to be effective in thickening sludge.