In 2017, when PFAS contamination was identified in private wells of hundreds of residents in Plainfield and Algoma Townships, Prein&Newhof and township leaders began planning how to provide them with much-needed municipal water service. Wolverine World Wide was testing hundreds of homeowners’ private wells for PFAS contamination and supplying bottled water, and to some, house filtration systems.
Prein&Newhof helped the Township perform a pilot study to determine if modifying existing rapid sand filter beds in the water treatment plant with GAC would reduce the amount of PFAS in the water supply. The grant covered the cost for modifying five existing filters and for extensive testing of raw and treated water for PFAS and other contaminants. The pilot program and construction, unique in that it was being done on a fully operational water system, included three phases to test different configurations to find the optimal design for removing PFAS. The first year of testing demonstrated that the modified filters successfully met all current water treatment requirements while also removing PFAS.
The expansion involved removing the current filtering materials and altering the filter bottoms with inserts to support the change to GAC filtration. Work also involved raising the piping to allow for a 52-inch thick bed of GAC filtration material, compared to the previous 37-inch bed of traditional filtration media.
Construction for the pilot project completed in fall of 2018 replaced filter media in five of the water plant’s filter beds with GAC, allowing the plant to treat up to 9 mgd. A subsequent project replaced three more filter beds with GAC media, raising the treatment output to 12 mgd and allowing even peak summer demands to be fully treated with GAC filtration. The water plant’s four remaining filters were not configured to accommodate the GAC filters, but were eventually modified—two in 2020 and the final two in 2021.
The Township now has 16 million gallons per day capacity under GAC filtration. The pilot study was foundational for future municipal treatment of compounds like PFAS, and has been beneficial to other municipalities facing similar drinking water challenges.