Sequential Treatment of Brewery Effluent using Vegetated Subsurface and Surface Flow Constructed Wetland

Abstract

This study investigated the efficiency of a sequential system involving surface flow and vegetated sub-surface flow constructed wetland (CW) in the treatment of Brewery Wastewater. Six experimental CW (2 surface and 4 subsurface flow) and control (1 surface and 2 vegetated subsurface flow) with 200 mm depth of 19.05 mm diameter granite and 100 mm depth of sharp sand as substrate were used for the experiment. The CWs were planted with locally available macrophytes: water hyacinth (Eichhornia crassipes), Cattail (Typha latifolia) and Vetiver grass (Vetiveria nigritana). The microcosms were irrigated using wastewater from Brewery Effluent (BE), pollution parameters were measured and treatment efficiency was monitored. The pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Dissolved Oxygen (DO) and Biological Oxygen Demand (BOD5) of the BE studied were 6.84, 1189 μs/m, 2998 mg/l, 9.4 mg/l and 1244 mg/l, respectively. Average reductions of 92.53, 48.30 and 67.16 % were observed in the TDS, BOD and Nitrate after treatment. The BOD5 percentage removal was higher in the Subsurface CW than in the Surface flow CW (30.11 and 49.04 % for surface and subsurface flow, respectively). The study showed that CW using surface and subsurface flow constructed wetland with locally available macrophytes is efficient in Brewery wastewater treatment.