City of Ann Arbor: 2014 - present
The city of Ann Arbor supplies water to city of Ann Arbor residents, as well as residents in Ann Arbor Township and Scio Township. The total population served is 127,855. The city of Ann Arbor gets 85 percent of its water from the Huron River via two water intakes in Barton Pond and 15 percent from multiple groundwater wells. Below is a timeline of PFAS-related activities:
- In 2020, EGLE will perform quarterly monitoring of the City of Ann Arbor’s water supply as part of the statewide initiative. Due to COVID-19 access restrictions, the first quarter sample could not be collected.
- The City of Ann Arbor, in collaboration with Dr. Detlef Knappe’s research group at North Carolina State University, are conducting pilot tests on both granular activated carbon and ion exchange for PFAS removal. The research is funded primary through a grant from the Water Research Foundation. The City is studying how media type, empty bed contact time, operating conditions, and other variables impact PFAS removal and breakthrough over time.The results of this research will be used to optimize the City’s current PFAS management strategy and to guide future investments needed for long-term PFAS management.
- In 2019, EGLE continued monthly sampling of the city of Ann Arbor’s water supply as part of the statewide initiative with all results below 10 ppt combined PFOS+PFOA.
- Mid-July 2018 – The city of Ann Arbor’s municipal water supply was tested as part of the EGLE’s statewide initiative to test all public water supplies and schools with their own wells. Both the finished water and the intake for the supply were sampled. The results were available mid-August and finished water results were 4 ppt PFOS + PFOA; intake results were 11 ppt PFOS + PFOA. Additional results are available on the public water supply statewide sampling initiative page.
- In late 2017, the city of Ann Arbor began a Granular Activated Carbon (GAC) filter pilot study for treating its water supply. The sand in two of the city of Ann Arbor’s 26 active filters was replaced with a full bed depth of GAC to evaluate whether the increased depth of GAC will improve the filters’ ability to remove contaminants. With favorable results from the pilot study, the sand in the remaining 24 filters was replaced with full GAC in the Spring of 2019. The GAC is replaced on a rotating basis every 5 years.
- March and July 2016 – The city of Ann Arbor conducted water sampling for PFAS; they tested raw water sources as well as finished water. All but one of these upstream locations had detectable levels of PFAS and no obvious source was able to be pinpointed. The sample locations were:
- Main water reservoir (treated water) and the raw river intake (untreated water).
- Two raw water production wells (untreated groundwater).
- Surface water within the Huron River, Barton Pond, and Honey Creek (upstream of the intake; untreated surface water). See map of surface water results below.
- October 2016 - The city of Ann Arbor began collecting monthly PFAS samples from the raw river source and finished water. The results are provided to EGLE monthly. To date, all the results obtained are below the USEPA Lifetime Health Advisory of 70 ppt, either individually or combined with the exception of a finished water result of 88.1 ppt in October 2018.
- March 5, 2014 – The city of Ann Arbor sampled for PFAS compounds in drinking water, as required by the United States Environmental Protection Agency (USEPA) under Round 3 of the Unregulated Containment Monitoring Rule (UCMR3). PFOS was detected in the drinking water sample (main reservoir – treated water) at 43 parts per trillion (ppt). Review the city of Ann Arbor’s 2014 Water Quality Report.