Treatment of pyrethroid pesticide industry wastewater by halotolerant bacteria using anaerobic post aerobic sequencing batch reactor

Abstract

Synthetic pyrethroids (SPs) are relatively less toxic pesticides that potentially serve as an alternative to toxic organochlorine and organophosphate pesticides and has been successfully employed in agricultural sector for more than 30 years in insect-pest management. However, an inappropriate discharge of these pesticides from pesticide manufacturing industries into the environment widely pollutes air, water and soil. Higher salinity and extreme toxicity of pesticide industrial discharges has also been revealed to be of challenging concern in wastewater treatment system and there is an urgent need for an efficient, reliable, cost-effective and eco-friendly biological method to completely eliminate these pesticides from the environment. To implement such needs, in the present research work biological treatment of pesticide contaminated wastewater was carried out to remove pyrethroids from pesticide industrial wastewater using halotolerant bacterial strains in an anaerobic-aerobic sequencing batch reactor. Physicochemical analysis of pesticide industrial wastewater revealed the presence of pyrethroid pesticides, heavy metals and other inorganic components. Pyrethroid pesticides detected as priority pollutants in all the collected samples were identified to be deltamethrin, cypermethrin, beta-cyfluthrin, lambda-cyhalothrin, and permethrin. Pesticide degrading bacterial consortium capable of utilizing pyrethroid pesticide as a sole carbon source in saline condition was enriched in pesticide industrial wastewater. Among three screened isolates VCRAM 1, 2 and 3, VCRAM-1 and 2 exhibited significant growth at 500 mg/L pyrethroid pesticide mixture under saline condition and showed gt88% and 85% degradation in 10 day in mineral salt medium. These bacterial strains were identified by morphological, biochemical and molecular analysis. newline