Interlochen State Park Wastewater Feasibility Study and ImprovementsInterlochen, Michigan

Gosling Czubak was selected and completed the preliminary engineering study for the viability of the old wastewater facility at the State Park in 2017. Work included performing composite sampling of wastewater from the main lift station, sludge depth sampling of existing lagoons, as-built review of original design drawings, comparison of original design to new design standards, review of recent Department of Environment, Great Lakes and Energy (EGLE) mandated sampling results, review of occupancy data and its relation to the strength of waste water, writing a report of our findings, which includes an analysis of costs to repair the existing facility and two alternatives, including a new treatment plant.

From the study, the DNR decided to move forward with improvements to the wastewater facility, initially with the addition of a headworks (preliminary screening) and ultimately with a full wastewater treatment facility.  Design for the treatment plant began in 2018 and experienced some delays due to pandemic related shutdowns.  Permitting and a full Hydrogeological Study, including the installation of three additional monitoring wells was completed during the engineering design phase.  Ultimately, the design was completed and bid in early 2021.  The final bid cost was $2.78M and was within ten percent of the original project estimate provided over eighteen months prior. 

The new plant was sized for an average daily flow of 17,000 gpd and a peak of 39,000 gpd and utilizes mechanical screening, Sequencing Batch Reactors, and tertiary filtration with chemical feed, before being discharged into Rapid Infiltration Basins.

The treatment facility was constructed on-time and within budget, even after several DNR requested additions.  The facility was operational by Memorial Day 2022, allowing the campground to open several weeks prior to the initial projection of July 1, 2022.