Nitrogen Removal from Biomethanated Spentwash Using Hydroponic Treatment Followed by Fungal Decolorization

A two-stage sequential treatment for anaerobically digested wastewater from a cane molasses-based distillery is proposed. In the first step, the wastewater was treated in a hydroponic based system using two plant species (Vetiveria zizanioides and Phragmites kharka) to reduce the high nitrogen (total Kjeldahl nitrogen) content of the effluent. Roots of these plants showed profuse growth on effluent. Nitrogen removal to the tune of 84% was achieved. When this hydroponically treated effluent was subjected for treatment by fungal isolates, 86.33% decolorization was obtained with Pleurotus florida Eger EM1303 followed by Aspergillus flavus TERIDB9 (74.67%), with significant reduction in chemical oxygen demand (COD) as well. The suggested method is thus important from the point of treating distillery wastewaters without the need of high dilutions and addition of supplementary carbon sources.