The West Bay County (WBC) Wastewater Treatment Facility (WWTF) in Bay City served one city and five townships when two more municipalities requested wastewater treatment services, for up to 2.3 million gallons per day (mgd). While WBC wanted to be accommodating and add more sewage to its plant, it needed to mitigate Sanitary Sewer Overflows (SSOs) for 25-year storm events. Before new customers could be connected, the Michigan Department of Environmental Quality (DEQ) required the wastewater treatment plant to create additional treatment capacity and mitigate overflows.
Adding flow equalization, addressing odors and inadequate biosolids storage capacity and improving the chlorine contact time for disinfection were priorities in the treatment plant expansion plans.
Fleis & VandenBrink completed a capacity study and provided design and construction engineering. The improvements expanded operational capacity of the wastewater treatment plant and eliminated sewage overflows into the Saginaw River and Saginaw Bay at a fraction of the price it would cost to expand facilities.
The innovative hydraulic design and installation of a high rate anaerobic digester helped eliminate odors, decreased sludge volume and captured greenhouse gas methane for energy use and reduced operating costs.
Key money-saving components were:
- Constructing a 50-million gallon clay-lined equalization basin, saving $1.7 million in liner construction costs.
- Innovative hydraulics consideration, saving $800,000 while increasing final clarifier capacity by 80 percent.
- Innovative hydraulics consideration at the chlorine contact tanks, saving $150,000.
In 2014, the project won ACEC-MI’s Eminent Conceptor Award for Engineering for saving millions of dollars while providing a sustainable design with increased plant hydraulic and biosolids treatment capacity for years to come.