Green approach for nutrients removal from real dairy wastewater via constructed wetland

Abstract

Constructed wetlands (CWs) are considered one of the most promising future approaches for wastewater treatment from various sources at relatively low cost and with minimised environmental impacts. In this study, an integrated system of CW cells with horizontal subsurface flow were designed, installed and fed with fresh actual dairy industry effluent in continuous base. To investigate the simultaneous effect of arrangement and type of supporting media on the treatment efficiency, six identically designed CW system cells were installed using conventional naturally available cost-effective supporting media. The type and configuration of supporting materials were 100% gravel, 50% sand and 50% soil, 60% gravel and 40% sand, 100% sand, 50% sand and 50% soil and 100 soil for CW1, CW2, CW3, CW4, CW5 and CW6, respectively. All CW cells were planted with Canna indica except CW5, which was kept uncultivated as the control cell. The results revealed significant removal of nutrients with maximum removal efficiencies of 99 and 96% for phosphate and nitrate, respectively. The favourable results confirmed that CWs can be used as an inexpensive sustainable technique for dairy effluent treatment.