270933 Optimizing Mercury Removal Processes for Industrial Wastewaters
Although typically occurring at ppb levels in wastewater discharge streams, the severe toxicity of many mercury compounds and their tendency to bioaccumulate in aquatic ecosystems has led to very stringent Hg discharge regulations being proposed and implemented in many regions of the US. Examples include the Ohio River Valley Sanitation Commission (ORSANCO) standard of 12 ppt Hg for discharges into the Ohio River and the Great Lakes Water Quality Initiative standard of 1.3 ppt Hg for discharges into bodies of water in the Great Lakes Basin. Meeting these limits presents a significant challenge to wastewater treatment engineers and environmental managers in many industries, including coal burning power plants, petroleum refineries, and chemical manufacturing plants.
This presentation will describe bench-scale and pilot-scale methods that have been successfully used to evaluate chemical additives and physical separation processes for their effect on mercury removal. Discussion will include how to use a total systems approach to develop the most efficient treatment program that will meet current and proposed Hg discharge standards. Results of studies on a variety of industrial wastewaters will be presented to demonstrate the mercury removal performance of several traditional and non-traditional chemical/equipment treatment combinations. Data from studies using a novel polymeric organosulfide additive will be highlighted for its proven ability to reduce mercury to low ppt concentrations.