fast facts – Twin Cities
Communities served: Retail customers include St. Paul, Lauderdale, Falcon Heights, Maplewood, West St. Paul, Mendota, and Mendota Heights. Restricted services are sold in South St. Paul, Lilydale, and Sunfish Lake. Arden Hills, Roseville, Little Canada, and the University of Minnesota have their own distribution pipes and billing services, but purchase SPRWS wholesale water.
How much water On average, St. Paul Regional Water pumps nearly 39 million gallons of water into the Eastern Underground every day. In 2020 the maximum daily output was 61 million gallons.
How much infrastructure? If laid end-to-end, the utility company’s 1,200 mile aqueduct would extend from Minnesota almost all the way to Mexico.
The process: While water from Lake Vadnais is pumped into the centuries-old McCarrons sewage treatment plant in Maplewood, alum and quicklime are mixed in as plasticizers. The water is then directed to massive clarifiers where heavier particles fall to the bottom and solids are collected and sent to a drainage facility where they are used as spent lime for agricultural applications. The clear water runs over the top of the clarifier into a recarbonization basin, where it is directed over a series of diffusers that push carbon dioxide into the water. The carbon dioxide lowers the acidity of the water or the pH value to 8.6. During this phase, liquid fluoride is added for dental health. Filters that use 36 inches of granulated activated carbon and a layer of sand then trap particles that aren’t heavy enough to fall out in the clarifiers, including algae molecules that can cause odor and taste problems. The filtered water then falls into a clear well and goes to a finished water reservoir where chlorine and ammonia are added to kill bacteria. From the reservoir, water is pumped through 1,200 miles of distribution network to 450,000 customers in St. Paul and the surrounding communities. SPRWS maintains 10 pumps of different sizes to pump water to different cities and districts.
The plan: The design of a modern new water treatment plant next to the existing one will continue until July 2022. The heavy construction work will begin in autumn 2022 and is expected to be completed in autumn 2025. Jacobs Engineering – based in Dallas, Texas, USA. with teams in Minneapolis, Denver and Milwaukee – signed a contract as a design-build company in January.