Enhanced contaminant removal from municipal wastewater using novel cascade cum trickling filter and multilayer adsorption bioreactor

Abstract

The novel two-stage treatment system consisting of cascade cum trickling filter (CCTF) and multilayer adsorption (MLA) bioreactor was developed to enhance the contaminants removal such as chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP). The maize cob and date palm fiber were used as biofilm support media in trickling filter. The MLA bioreactor was operated using the composite adsorbent (refused crushed brick + rice husk + steel slags). The maximum adsorption uptake of composite adsorbent was observed as 0.6 mg/g for ammonium and 3.5 mg/g for phosphorus. Kinetic analysis showed that the composite adsorbent had a faster removal rate for phosphate than ammonium. The maximum desorption of ammonium and phosphate was found to be 14.6% and 6.5%, respectively. The performance of both cascade cum trickling filter and multilayer adsorption (CCTF-MLA) systems was also evaluated using the various COD-TN ratios and flow rates. The removal efficiencies of COD, TN and TP were found 93%, 87% and 86%, respectively, and their corresponding mean effluent concentrations were noted 18 mg/L, 5.5 mg/L and 2.3 mg/L. The developed CCTF-MLA system removed the 3log of the total count and total coliform and 2log of Escherichia coli and salmonella. So, the CCTF-MLA system could be efficient for wastewater treatment due to the steady removal rate of COD, TN and TP.