Two stage treatability and biokinetic study of dairy wastewater using bacterial consortium and microalgae

Abstract

Purpose of present research work is to perform nutrient removal and evaluate bio-kinetic coefficients of a two-stage dairy wastewater treatment process in batch reactor using bacterial consortium and microalgae Chlorella pyrenoidosa. The research work was performed in laboratory-scale batch reactor. Primary treated real life dairy wastewater after a treatment with a consortium of bacterial population containing carbon oxidation and nitrification bacteria was taken as the feed material for algal treatment process using microalgae C. pyrenoidosa strain. Nitrate nitrogen which was formed during bacterial nitrification still remaining in bacterial pre-treated dairy wastewater along with phosphorus that have been removed by algal treatment using microalgae of C. pyrenoidosa. The present investigation was done for bacterial and algal treatment of dairy plant effluent in a lab-scale batch reactor with acclimatized seeds of both carbon oxidation, nitrification bacteria, microalgae C. pyrenoidosa and also to evaluate various biokinetic coefficients. Around 95% ammonium nitrogen and soluble chemical oxygen demand (SCOD), around 99.67% and 90.25% of Nitrate nitrogen (NO3−-N) and Phosphorus (PO43-- P) removal were achieved corresponding to initial ammonium nitrogen and SCOD of 55 and 720 mg/L, nitrate nitrogen and phosphorus concentration of 54 and 16 mg/L respectively, with an initial inoculum concentration of bacterial consortium of 15%; corresponding to 1500 mg/L and microalgae C. pyrenoidosa of 0.8% v/v; corresponding to 80 mg/L after 24 h and 8 days of detention period in batch reactor respectively. Kinetic study was also carried out to obtain bio-kinetic coefficient for SCOD, ammonium nitrogen, nitrate nitrogen and phosphorus removal using bacterium and microalgae C. pyrenoidosa.