Performance evaluation of fabric aided slow sand filter

In this study, performance of non-woven synthetic fabric (NWF) aided SSF was evaluated in a laboratory scale setup. NWF was selected based on the specifications suggested in literature. Three filters with different thicknesses of fabric on sand beds and one filter without fabric were studied with simulated raw water prepared in laboratory.; The results revealed that there was no significant increase in filter run time for the filters with fabric as compared to the one without fabric. However, NWF captured most of the particles, and significantly protected the sand beds from particles deposition. The sand bed protection time was increased linearly with fabric depths. 22.3 mm thickness of selected NWF protected the sand bed for a longer period as compared to 8.9 mm thickness of fabric. Even though NWF showed no significant increase in filter run time, it allowed non sand-bed disturbing filter cleaning operation by protecting the sand bed. The fabric also supported the biogrowth and schmutzdecke development, which contributed to a significant portion (>60%) of total organic carbon (TOC), total coliform and turbidity removal. Removing top one or more fabric layers, after previous filter runs, reduced the time required for filter ripening. Cleaning of fabric by pressurized tap water was convenient and restored the clean bed head loss. (Abstract shortened by UMI.)...