MWRD unveils new disinfection facility at Calumet Water Reclamation Plant
The Metropolitan Water Reclamation District of Greater Chicago has unveiled its new disinfection facility at the Calumet Water Reclamation Plant.
July 20, 2015 -- On Friday, July 17, the Metropolitan Water Reclamation District of Greater Chicago (MWRD) unveiled its new disinfection facility at the Calumet Water Reclamation Plant (WRP). The new utility is designed to improve the water entering the Chicago Area Waterways (CAWS) from the utility, which serves more than one million people in a 300-square-mile area covering the South Side of Chicago and surrounding south suburbs.
The new step in MWRD's water treatment protocols will include the chlorination and dechlorination process. This will reduce the amount of pathogenic bacteria in the water released from the plant into the Calumet River system. Disinfection technologies neutralize or kill bacteria and microorganisms in treated water and reduce the risk of health problems resulting from direct contact with the water while recreating on a waterway. Disinfection occurs after wastewater passes through a series of treatment processes, including screening, filtering, settling, and microbial aeration.
In addition to the disinfection facility at the Calumet WRP, MWRD is also building a similar facility at the O'Brien WRP in Skokie by implementing an ultraviolet (UV) irradiation system to disinfect water entering the CAWS. The District has allocated resources and funding to allow disinfection to occur without increasing taxes.
As recent as 2011, the CAWS had secondary classification for water quality standards, meaning direct contact with water was not possible outside of boating. However, in advance of a possible decision by the EPA to one day re-classify the CAWS for allowing primary contact, the MWRD Board of Commissioners adopted a policy to disinfect on June 7, 2011. MWRD officials instituted a blue ribbon panel to evaluate available disinfection technologies and devoted eight months to research and testing to determine optimal solutions for disinfecting at the most economical cost.
Using an existing chlorine contact chamber retrofitted for more efficient contact, the disinfection technologies neutralize or kill bacteria and microorganisms in treated water. Engineers modified the existing chlorine contact basin by replacing all interior baffle walls and associated walkways; replacing weir gates, discharge gates, drain sluice gates, inlet sluice gates, and a bypass sluice gate; replacing liquid sodium hypochlorite diffuser piping; installing liquid sodium bisulfite diffuser piping; and installing sampling pumps.
In operation since 1922, Calumet WRP is the oldest of the seven MWRD plants in operation. The facility, which is home to 268 employees, will treat an average 354 million gallons per day and a maximum 430 million gallons per day.