Treatment system reduces arsenic to non-detectable levels for village of DeWitt, Ill.
The village of DeWitt is a small community of approximately 200 residents located in central Illinois. The community had an outdated filter system not meeting regulatory compliance. Berns, Clancy, and Associates contacted AdEdge Water Technologies  in 2011 to design, manufacture, and startup an arsenic, iron and manganese, and hydrogen sulfide removal system for the Village of DeWitt. Prior to the full-scale system, AdEdge commissioned a pilot study in January 2013 to verify the treatment approach due to the challenging water chemistry. The raw water contained high levels of phosphate, ammonia, TOC, hydrogen sulfide, iron, manganese and arsenic.
The AdEdge treatment system was designed for a maximum flow of 50 gal per minute. The system is comprised of four 24-in. carbon steel vessels arranged in a parallel configuration. The vessels are loaded with AdEdge’s AD26 oxidation/filtration  media for the removal of arsenic, iron and manganese, and hydrogen sulfide. AD26 media is a NSF 61-certified manganese dioxide based filter media. The high filtration rate of the AD26 media allows for the removal of the contaminants while maintaining the existing building’s small footprint.
The AD26 media in the presence of a strong oxidant, which is injected into the raw water, acts as a catalyst for the accelerated removal of the contaminants. The programmable logic controller (PLC)  initiates an automatic backwash of the treatment vessels to remove any precipitated solids that may accumulate in the media bed and to extend the life of the AD26 media. Backwashing of the treatment vessels occurs one vessel at a time to ensure water is continuously being treated throughout the day. The system fully integrates with the existing post-chlorination system that addresses the high ammonia levels in the water before going to distribution.
The treatment system was successfully commissioned in July 2013. More than 30,000 gal of water are treated on a daily basis. The levels of arsenic have lowered from 0.020 mg/L to non-detectable levels. The iron and manganese levels are reduced from 5.3 mg/L and 0.12 mg/L to below the treatment goals of 0.3 mg/L and 0.05 mg/L, respectively. Hydrogen sulfide also has been lowered to a non-detectable level.
Richard J. Cavagnaro is marketing coordinator for AdEdge. Cavagnaro can be reached at [email protected]  or 678.835.0052.