Removal of endosulfan using aerobic mixed bacterial culture

With the increasing use of pesticides in modem agriculture, increased evide nce of their disastrous effects on the environment has been noticed. Pestic ides applied in various modes and places contaminate various parts of the e nvironment, including groundwater sources. As pesticide problems are greate r in the rural areas, the authors have developed a successful low-cost tech nology for rural areas with wood charcoal treated with nitric acid. As pest icides are classified as hazardous waste, the sludge resulting from their t reatment has to be disposed off safely. This paper describes the removal of pesticides at a higher concentration of 24 mg/l, using a mixed culture of aerobic bacteria, and also a study of the inhibiting action of endosulfan o n bacterial cells. It was found that bacteria without acclimatization could remove 89.7% of endosulfan, and with prior acclimatization the efficiency was 96%. It was found that removal in the initial phase is because of the h ydrophobic nature of endosulfan and its affinity to sediments. The adsorbed endosulfan subsequently undergoes bio transformation, which has been confi rmed by monitoring endosulfan concentrations in the bacterial sludge. Trans formation was found to be significant in the acclimatized culture system. T he fluctuation in bacterial performance was greater at lower concentrations of endosulfan, and overall inhibition was greater at higher concentrations .