St. Paul Regional Water Services: fast facts

Communities served: Retail customers include St. Paul, Lauderdale, Falcon Heights, Maplewood, West St. Paul, Mendota, Mendota Heights. Limited services are sold in South St. Paul, Lilydale and Sunfish Lake. Arden Hills, Roseville, Little Canada and the University of Minnesota own their own distribution pipes and billing services but purchase SPRWS water wholesale.

How much water? On average, St. Paul Regional Water pumps nearly 39 million gallons of water per day to the east metro. In 2020, the maximum single-day output was 61 million gallons.

How much infrastructure? If laid end-to-end, the utility’s 1,200 miles of water mains would stretch from Minnesota almost to Mexico.

The process: As water is pumped into the century-old McCarrons treatment plant in Maplewood from Lake Vadnais, alum and quicklime are mixed in as softeners. The water is then transferred to massive clarifiers, where heavier particles drop to the bottom and solids are collected and sent to a dewatering facility, where they will be used as spent lime in agricultural applications. The clear water spills over the top of the clarifier into a recarbonation basin, where it passes over a series of diffusers that force carbon dioxide into the water. The carbon dioxide lowers the acidity level of the water, or pH, to 8.6. Liquid fluoride is added in this phase for dental health. Filters using 36 inches of granular-activated carbon and a layer of sand then capture particulate matter not heavy enough to drop out in the clarifiers, including algae molecules that can cause odor and taste issues. The filtered water then drops into a clear well and travels 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 mains to 450,000 customers in St. Paul and surrounding communities. SPRWS maintains 10 pumps of various sizes for pumping water to different cities and neighborhoods.

The plan: Design of a modern new water-treatment plant next to the existing one will continue into July 2022. Heavy construction will begin in the fall of 2022 and is projected to wrap up in the fall of 2025. Jacobs Engineering — based in Dallas, Texas, with teams in Minneapolis, Denver and Milwaukee — signed a contract in January to serve as the design-build firm.

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