No abstract

A chromate-removing strain was isolated from spent chrome effluent and identified as Bacillus circulans strain MN1. The isolated strain was studied for resistance to Cr (VI) and its ability to remove Cr (VI). The strain was found to tolerate Cr (VI) concentration as high as 4500 mg/L, but the cells growth was heavily influenced when initial Cr (VI) concentration was increased between 1110 mg/L and 4500 mg/L while Cr(VI) at 500 mg/L to 1110 mg/L did not suppressed the cells growth. The experiments also demonstrated that the cells removed toxic Cr (VI) more efficiently at 30?C compared with that at 25?C and 35?C. The optimum initial pH for Cr (VI) removal was 5.6 and final pH values of 5.1-5.6 were observed for initial pH 5.2-5.7

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This study assesses the long-term sustainability for operation and maintenance (O&M) of sewage-fed aquaculture-based sewage treatment system. The study focused on the integrated assessment of an engineered pond system of 8 million liters per day capacity in the city of Karnal, the State of Haryana, northern India. Major areas during the assessment included health, environmental, societal and institutional views aspects as well as the quality of treated effluent subjected for reuse. The treatment facility met the Indian regulatory standards (downstream reuse and discharge into the legally permitted water bodies) in terms of physical-chemical parameters. The total coliform and faecal coliform removal were up to 2-3 log units; nevertheless, it was not capable to come across the bacterial count requirement (<1,000 per 100 mL to minimise human health risk in aquaculture practices). The system was able to generate sufficient net income required for routine O&M. Annual revenue collected by the Municipal Corporation from the lease of the facility as well as selling of treated wastewater was $3,077 and $16,667-$25,000, respectively. The additional benefit from the facility for the farmers included the saving of fertilizers and cheapest source of water available for irrigation. Recycling of treated sewages for irrigation is also returned nutrients to the surrounding farms in Karnal. This exercise has saved significant quantities of chemical fertilizer (26-41 Ton of nitrogen, 10-18 Ton of phosphorous and 38-58 Ton of potassium per year) and the overall benefit for farmers during cultivation of one acre of crop was calculated to be approximately $133 per year.