Treatment of dairy industry wastewater by combined aerated electrocoagulation and phytoremediation process

Abstract

As dairy industries has been emerged as one of the most rapidly developing industry in both small as well as large scale, the volume of effluent generated is also very high. In the present study, aerated electrocoagulation combined with phytoremediation treatment was conducted in dairy industry wastewater. Electrocoagulation was performed with aluminium and iron electrodes and effect of various operating parameters such as electrode combination, pH, and voltage were tested. Electrocoagulation was found effective at neutral pH and its efficiency increased with increase in applied voltage. The maximum COD removal efficiency of 86.4% was obtained in case of Al–Fe electrode combination with aeration at 120 min reaction time, initial pH 7, voltage 5 V. Significant growth of Canna indica was observed in electrocoagulation treated wastewater compared to raw dairy wastewater. COD removal of 97% was achieved when combined electrocoagulation and phytoremediation process was used. Thus, it proves to be a proficient method for the treatment of dairy industry wastewater. In addition to the above, bacterial toxicity tests were performed to investigate the toxic nature of wastewater and the results showed that both treated and untreated wastewater favoured bacterial growth.