Membrane fouling characterization in membrane-based septic tank

Abstract

Septic tank is a conventional on-site wastewater disposal system providing only primary treatment (settlement of solids), while offering little biological degradation. To further improve the quality of treated water, the conventional septic tank can be modified by the introduction of membrane module capable of effective rejection of suspended solids as well as associated particulate organic matter. However, membrane fouling by partially-treated water can be considered as one of the major limitations of the membrane-based septic tank (MBST) system. The present study was carried out in a pilot-scale MBST by using flat-sheet woven fiber microfiltration (WFMF) membrane modules. WFMF membrane module having 1 m2 effective filtration area was submerged in septic tank of 4 m3 working volume and operated at different fluxes to investigate the fouling frequency and effects of cleaning protocols. It was found that the physical cleaning protocol was effective in removing cake as well as partial pore blocking resistance without requiring chemical cleaning. On the other hand, after each operation cycle, the irreversible fouling of membrane increased.