Treatment of industrial wastewater using photooxidation and bioaugmentation technology

Abstract

The versatile metabolism of microorganisms has an played important role in the biodegradation of recalcitrant toxic compounds entering into the natural environment. The biodegradability of organics can be enhanced using bioaugmentation and advanced oxidation processes (AOP) for aerobic/anaerobic treatment programs. Wastewater from a bulk drug (cresol) plant had high levels of TDS, COD and BOD, whilst the levels from a pigment plant low. Both contained organics difficult to degrade. AOP using hydroxyl radical generated in 1 L glass reactor using UV and H2O2 efficiently oxidised phenol and cresol. COD and sulphite reduction in cresol containing wastewater were 20-60% in 1-6 h. A twenty to thirty percent reduction in copper phthalocyanine pigment effluents was achieved in 6 h using AOP. Strains of Micrococcus, Pseudomonas, and Nocardia degrading phenol, cresol were isolated from soil and sludge. Mixed biomass of these organisms removed phenols (1,000 ppm) and cresols (500 ppm) completely in 24 and 72 h, respectively. The COD and BOD reductions under the optimum nutritional and physiological conditions were in the range of 70 to 90%. When added to the bioreactor, 20% of the developed biomass of mixed strains of Micrococcus, Nocardia and Pseudomonas increased the rate of COD and BOD reduction gradually and stabilised at 80-90%. Added biomass improved the overall efficiency of the aerobic process.