Nutrient removal from synthetic and secondary treated sewage and tannery wastewater through phycoremediation

Abstract

In this study, potential microalgae species (Chlorella vulgaris, Scenedesmus dimorphus, Chlorococcum sp. and Chlamydomonas sp.) have been studied for nutrient removal from synthetic and industrial wastewater. Batch experiments were carried out to investigate the removal performance among four chosen species at different nitrogen and phosphorus concentrations. NH₄-N and PO₄-P were varied from 13.2 to 52.8 mg/L and 6.6 to 26.4 mg/L, respectively, by keeping N:P ratio as 2:1. In synthetic wastewater, maximum NH₄-N and PO₄-P removal efficiencies of 88.6% and 91.2% were obtained with C. vulgaris when compared to the other microalgae studied. Further studies were carried out using C. vulgaris in batch experiments to investigate the nutrient removal performance in secondary treated sewage, soak liquor and composite tannery effluent. Experimental results indicated that NH₄-N, NO₃-N, PO₄-P and chemical oxygen demand (COD) removal efficiencies were found to be 68.6%, 74%, 71.5% and 90.2%, respectively, in secondary treated sewage. Maximum removal efficiencies of NH₄-N, NO₃-N, PO₄-P and COD in composite tannery wastewater were found to be 55%, 85.6%, 60.5% and 43.4%, respectively. In soak liquor, maximum removal efficiencies of NH₄-N, NO₃-N, PO₄-P and COD were found to 66.7%, 62.6%, 63.6% and 93.8%, respectively.