Treatment of toxic industrial effluent containing nitrogenous organic compounds by integration of catalytic wet air oxidation at atmospheric pressure and biological processes

Abstract

The treatment of non-biodegradable industrial effluent containing toxic pyridine compounds by integration of catalytic wet air oxidation (CWAO) and biological processes has been studied. The CWAO experiments were performed using ceria promoted Pt/Al2O3 catalyst. The catalyst was characterized by various techniques and the stability of the catalyst was studied. The research intended to achieve two main objectives: a) biodegradability enhancement of toxic industrial effluent by CWAO which is operated at mild conditions and b) complete mineralization of effluent obtained after CWAO treatment by biological processes. Therefore, the CWAO experiments were performed at atmospheric pressure and the effect of various operating parameters such as ceria loading, catalyst dosage and temperature on Chemical oxygen Demand (COD) removal of industrial effluent was optimized. The CWAO reaction followed a first order reaction kinetic model. The catalyst stability test was performed to determine its reusability and the catalyst was found active after 3 cycles run. The biodegradability of the industrial effluent was found to be improved from 0.07 to 0.56 and toxicity was completely removed after CWAO treatment. The effluent obtained after CWAO was further treated with biological aerobic treatment and a total COD removal of 98.4% was obtained after 10 days of aerobic treatment.