Abstract: Applied Biosciences has developed a biological technology for removal of arsenic, nitrate, selenium, and other metals from mining and industrial waste waters. The ABMet((R)) technology was implemented at a closed gold mine site in Canada for removing arsenic from tailings pond water. The system included six bioreactors that began treating water in the spring of 2004. Design criteria incorporated a maximum flow of 567 L/min (150 gallons per minute) and water temperatures ranging from 10 degrees C to 15 degrees C. Influent arsenic concentrations range from 0.5 mg/L to 1.5 mg/L. The ABMet((R)) technology consistently removes arsenic to below detection limits (0.02 mg/L). Data from the full scale system will be presented, as well as regulatory requirements and site specific challenges.