Phosphorus Removal in Vertical Flow Reed Beds using Baked Clay Balls as an Alternative Media

Abstract

Phosphorous (P) entering into the water bodies through point and non-point sources is a causal agent for eutrophication. Nature Based Solutions (NBS) like Constructed Wetlands (CW) are cost effective methods for treating the grey waters in order to protect the water bodies form risk of eutrophication. The P removal efficiency of Constructed Wetlands (CW) can be improved by adding new substrate having potential P removal efficiency.The study was conducted to determine the phosphorus removal from wastewater using Baked Clay Ball (BCB) media in Vertical Flow Reed Beds (VFRB). The BCB was prepared with a mixture of river clay and saw dust. The field and lab-scale experimentation were set and operated in batch feeding mode using institutional wastewater for four months. The VFRBs were filled with BCB and planted with locally available reed grass (Phragmites karka). The hydraulic retention period in VFRB was 48 hours. Prime goal of the experiment was to investigate the Phosphorus (P) removal efficiency of the VRFBs apart from other conventional wastewater quality parameters. The concentration of phosphorus of the institutional wastewater was in the range of 27.3 mg/l to 16.3 mg/l. The average phosphorus removal efficiency of the VFRB 1 and 2 filled with BCB was 93.47%, while the average P removal efficiency of gravel filled VFRB 2 and 3 was 68.20%. Thus the experiment reflected that the BCB is a better media than the gravel for P removal. Therefore, the BCB may be used at a field scale to remove P from wastewater in constructed wetlands.Further, there is scope to develop new substrate materials focusing on its P retention capacity, long lasting performance and cost of the substrate to be applied in real treatment situations.