Evidence that BAC treatment enhances the DOC removal by enhanced coagulation

Effluent organic matter (EfOM) in secondary wastewater effluent (SWWE) contains a wide range of organic compounds, which varies depending on wastewater treatment plant performance. Its removal is required for various reuse/recycling applications. Traditionally, enhanced coagulation (EC) process is followed by biological activated carbon (BAC), EC/BAC combination, in order to obtain additional dissolved organic carbon (DOC) removal. However, this study elucidates the effectiveness of BAC/EC combination by modelling DOC removal resulting from EC of SWWE and BAC effluent obtained at different empty bed contact time (EBCT). The result suggests that BAC reduces the coagulant non-sorbable DOC concentration significantly which otherwise remains unaffected by the traditional combination. Further, non-sorbable concentration decreased with increased EBCT. This clearly indicates the crucial role of biological activities on increasing the performance of coagulant.