SIRWA plant to use sand filter system

As Southern Iowa Rural Water Association prepares to open its new water treatment plant early next year, the organization provided a fundamental explanation of how it will work for its approximately 11,500 customers.

Construction on the plant began in fall 2021 as it decided to have its own plan rather than acquire water from Creston Waterworks which it has done for years.

When operational, SIRWA will use water from Three Mile Lake. After water is taken from the lake it begins a process of coagulation as alum and other chemicals are added to create tiny, sticky particles called floc. The floc attracts dirt particles. The combined weight of the dirt and the floc create enough weight for it to sink to the bottom of the holding tank.

As the heavy floc settles to the bottom, clear water moves to the filtration step in the process. The filtration system passes through layers of filters. The layers include sand, gravel and charcoal. Those filters remove even smaller particles of unwanted items.

After filtration, chlorine is added to remove any bacteria and micororganisms that remained after filtering. The water is then piped to water towers for additional disinfection before it is distributed to customers.

Creston Waterworks uses a carbon filtration process. In a fundamental explanation, untreated water is sent through a carbon-based filter. The carbon is prepared in a way to prevent the unwanted contaminants from continuing in the water preparation process.