Press Release – 2019 Lake Auburn Alum Treatment

Weather permitting, starting on July 10, the Auburn Water District/Lewiston Water Division will move forward with an Alum Treatment of Lake Auburn to remove phosphorus in the water. Alum (aluminum sulfate) is widely used in drinking water treatment plants as a coagulant and in Lake to improve water quality.

A lake water quality issue that occurred on 2012 prompted the pursuit of a permit from the Maine Department of Environmental Protection (DEP) to apply an algaecide to the lake if necessary in the future. In September 2018 we applied an algaecide to the lake as the result of an algae bloom that caused taste and odor complaints from our customers. All drinking water standards were met before, during, and after these events.

On December 2018 our Management Staff, Consultants, and State Officials met and agreed that an Alum Treatment to Lake Auburn in 2019 was the best option to improve the quality of our drinking water. In May we received a permit from the DEP to apply Alum to Lake Auburn.
Phosphorus helps promote algae growth in the Lake and in this application, the alum will bind the available phosphorus and sink it to the bottom of the lake. As an added benefit, some of the phosphorus that is present in the lake sediments will bind with the Alum and not allow it to be released into the water column.

Based upon similar projects that have been done here in Maine, we anticipate several years of improved water clarity that will “buy us time” to implement additional watershed protection efforts that will limit the amount of phosphorus that is entering the lake.

This project will involve a one-time dose of 2mg/l over ¾ of the lake. The application will occur over 3-4 weeks from a barge with a submerged diffuser bar. The application will be closely monitored and documented.
Due to the chemical nature of Alum, and the fact that the concentration of this application will be very low, we do not anticipate any measurable impacts on fish or aquatic organisms A “no alum treatment” area will be maintained around the drinking water intake during application to assure alum floc settles out, and the water treatment plant will operate as normal during the application. The boat launch will be open as well. We will closely monitor and test the water before, during, and after the application to assure we continue to meet all drinking water standards.

Questions concerning this project should be directed to:
Sid Hazelton, P.E.,
Auburn Water District Superintendent
Kevin Gagne, P.E.
Lewiston Water Division Superintendent
Lewiston Water