AWWA ACE58285

Detroit Water and Sewerage Department (DWSD) provides drinking water for nearly 4 million people throughout Southeast Michigan. DWSD has five water treatment plants, which supply water to the City of Detroit and approximately 125 suburban communities in southeast Michigan. The stated treatment capacity for the combined five plants is approximately 1.7 billion gallons per day. The Department has been faced with the upgrade of many critical components of the drinking water treatment and delivery system, parts of which were constructed in the 1920s through the 1950s. The Department has been committed to providing its water customers with the highest quality water and has made a concerted effort to stay well ahead of upcoming SDWA regulations. This effort has required DWSD to undertake initiatives that provide ongoing treatment studies, as well as major plant upgrades to ensure that capacity can be reliably maintained. DWSD developed finished water quality goals that include removal and/or inactivation of Cryptosporidium, Giardia and Virus. Stringent turbidity goals aligned with the Partnership for Safe Water and a desire to control periodic episodes of taste and odor causing compounds, including geosmin and MIB, are at the heart of treatment goals and plant upgrades. One of the significant challenges has been the evaluation of the retrofit construction of new technologies such as ultraviolet disinfection or ozone into the existing plants. This paper discusses the unique challenges of large older plants and the solutions DWSD has developed. The two plants that are discussed include the 540 mgd Springwells Water Plant and the 240 mgd Southwest Water Plant. Includes tables, figures.