Performance of biofilters in GAC-sand and anthracite-sand dual-media filters in a water treatment plant in Abadan, Iran

Abstract

Biological water treatment using granular activated carbon (GAC) and anthracite improves water quality by reducing total organic carbon (TOC), colour, nitrogen content and turbidity. This study investigated the operation of aerobic biofilm on two pilot biofilters designed to remove turbidity, TOC, and in water. The results show that the GAC-sand pilot filter at a low hydraulic loading rate (HLR) increased the empty bed contact time and recorded the highest production of heterotrophic bacteria and biofilm, which increased the efficiency of treatment. Breakthrough occurred in the GAC-sand pilot filter at 72 h and low HLR, but occurred sooner for medium and high HLRs at 48 and 24 h, respectively. The run-time for the anthracite-sand pilot filter at high, medium and low HLRs was 70, 46 and 22 h, respectively. The microorganisms Pseudomonas, Bacillus and Citrobacter were identified in the GAC-sand filter.

Keywords:

• TOC
• Biofilm
• Anthracite
• GAC
• Water treatment