Arsenic (III) oxidizing Microbacterium lacticum and its use in the treatment of arsenic contaminated groundwater

Aims: To develop a microbially-assisted process for the removal of arsenic from contaminated groundwater. Methods and Results: A culture of Microbacterium lacticum oxidizing up to 50 mmol l(-1) arsenic (III) was isolated from municipal sewage by an enrichment culture technique. Using culture immobilized on brick pieces and packed in a glass column, complete oxidation of As (III) from groundwater could be quickly achieved at neutral pH and ambient temperature with methanol as substrate. The oxidized As species were removed from groundwater using three different methods: zero valent iron, activated charcoal and ferric chloride. Conclusions: The oxidation of groundwater As (III) by a M. lacticum-immobilized column, followed by its removal using activated carbon, could be an efficient method for the treatment of As (III)-contaminated groundwater. Significance and Impact of the Study: The study will be useful in developing a combined microbiological-chemical process for treating arsenic-contaminated groundwater.