Sequential batch reactor for dairy wastewater treatment: Parametric optimization; kinetics and waste sludge disposal

Dairy industry wastewater is characterized by high nitrogen load and chemical oxygen demand (COD). Present study deals with treatment of simulated dairy wastewater (SDW) in terms of COD and total Kjeldahl nitrogen (TKN) removal by aerobic sequential batch reactor (SBR). SBR was optimized for various operating parameters and four phase study was carried out by varying hydraulic retention time (HRT), filling time of SDW to the reactor, anoxic phase introduction after filling phase and react phase. Kinetic study has also been performed at various HRT. Optimum HRT (HRTopt) of 1 d with volume exchange ratio of 0.5 was found to sufficient to treat SDW. In view of fixing the problem of disposal of wasted activated sludge (AS) during the SBR cycle, elemental and thermo-degradation analysis of sludge was performed to understand its thermal degradation characteristics and possibility to utilize wasted AS as fuel.