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Lyon Township Wastewater Treatment Plant (Lyon Township, Oakland County)

EGLE Site Lead: Sydney Ruhala , RuhalaS@Michigan.gov or 517-599-5356. Webpage last updated June 22, 2022.

Background

The Lyon Township Wastewater Treatment Plant (WWTP), located at 53656 Ten Mile Road, discharges treated wastewater to the groundwater under a state Groundwater Discharge Permit issued to Lyon Charter Township (township). The treatment system consists of sequencing batch reactors and a chemical feed system. The final treated effluent is discharged to the groundwater on-site via rapid infiltration basins located in two discharge areas (i.e., the eastern and western rapid infiltration basins). The WWTP also has an approved Industrial Pretreatment Program (IPP), which requires industrial dischargers that send their wastewater to the WWTP, to use treatment techniques and management practices to reduce or eliminate the discharge of harmful pollutants to the sanitary sewers.  The IPP is designed to protect the municipal WWTP and the environment.

As part of a statewide sampling effort, EGLE sampled the WWTP’s influent, effluent, final treated solids, and four groundwater monitoring wells for PFAS in Fall 2021. 

Estimated groundwater flow direction across the eastern rapid infiltration basins and WWTP is to the northwest, west, or southwest depending on location, while estimated groundwater flow direction across the western rapid infiltration basins is to the southwest. 

Map of Lyon Township Wastewater Treatment Plant PFAS  

Recent Accomplishments

  • On November 3, 2021, EGLE contractors sampled the influent, effluent, final treated solids, and four downgradient groundwater monitoring wells for PFAS at the WWTP as part of a statewide sampling effort. 
  • On January 19, 2022, EGLE received the sampling results. All four monitoring wells exceeded groundwater cleanup criteria for PFOA. The highest result was 40.1 ppt PFOA. Two of the monitoring wells were located downgradient from the eastern rapid infiltration basins and two were located downgradient from the western rapid infiltration basins. 

Next Steps

  • EGLE will continue to work with the township to determine the extent of PFAS contamination in groundwater at the WWTP.
  • EGLE will continue to work with the township to determine potential sources of PFAS to the WWTP and implement source reduction controls under their IPP.
  • EGLE, MDHHS, and the Oakland County Health Department are working with the township to identify nearby residential wells and determine if sampling for PFAS is needed.

Residential Well Testing/Alternate Water Information

  • EGLE, the Michigan Department of Health and Human Services (MDHHS), and the Oakland County Health Department are working with the Township to identify nearby residential wells and determine if sampling for PFAS is needed. The two public water supply wells for the Township were initially sampled in July 2018. Both wells were non-detect for PFAS.

Upcoming Community Engagement

  • None Scheduled at this time.

Sampling Results Summary: PFOS and PFOA Only

Type of Sample

Date Sampled (or Range)

Number of Sample Results Received

Number of Samples above Criteria

Groundwater Monitoring Wells

November 3, 2021 4 4
*Residential well and groundwater monitoring well results are compared to EGLE Part 201 criteria for 7 PFAS compounds effective 12/21/2020:  PFOS (16 ppt), PFOA (8 ppt), PFNA (6 ppt), PFHxS (51 ppt), PFHxA (400,000 ppt), PFBS (420 ppt), and HFPO-DA (370 ppt).

Sampling Notes

  • None at this time.