Wellhead Treatment
Background
The Aquifer that supplies the City’s water system has a very high Iron concentration this can cause rust colored discoloration to the water delivered to homes. The high iron level is not a health concern it is more of an aesthetic problem that can be frustrating for residents. Recently the Minnesota Department of Health has issued new health guidelines regarding Manganese levels, the City is conducting resident water sampling in the Old Village, which has shown elevated Manganese levels. The Northeast supply system is below the new manganese recommended levels.
Currently the City treats the raw water with chemicals at the well before it is released into the water distribution system. The chemical treatment is effective to a degree, but cannot remove all of the Iron content from the water at the elevated concentrations present in the aquifer. To successfully remove all of the Iron the water needs to be filtered for the particulate material.
Solutions
Staff have been working with a consultant who specializes in water quality solutions. There are two options that have been identified which would allow the City of Dayton to control the quality of water being delivered to residents.
A.) Build a centralized water treatment plant. The plant would serve the Northeast and Northwest population of Dayton. This is a big project with an estimated cost for the plant of $25,000,000. There would also be substantial cost of extending water main from the Old Village to the North East location of the water treatment plant and possibly additional water main from the existing wells in the North East to the treatment facility. This treatment plant would be sized for the full build out water consumption which would not be required for many years.
B.) Build a smaller well head water treatment plant, that could treat up to two wells. This facility would be built in the location of the wells and would not require the Northeast and Northwest systems to be connected to each other. This solution is scalable so facilities are only built as they are required to maintain peak water service. The project cost per facility is around $4,000,000. Staff is currently considering two plants for an approximate cost of $8,000,000.
Finance
Funding for the project would come from the Water Utility Fund, which is funded from Development projects and water usage billing. The improvements would be funded from residents who are served by the Municipal water system. There would be no tax increases to pay for these improvements. Staff have applied for Federal and State Grant Funding for these projects, we are waiting to hear if our applications were successful.
The City was recently awarded a 4 million dollar Federal grant for the wellhead water treatment facility. Should the City Council decide to move forward with this project, the City will receive the $4 million (and possibly additional funding). More information will be posted on our website as it becomes available.
Actions
Recently the Council approved the City Consultants to prepare preliminary Engineering plans for two well head water treatment plants, one in the Northeast and one for the Northwest service areas of Dayton. The cost for these preliminary plans is included in the cost estimates outlined for the projects.
