The Village of Solon Springs’ wastewater treatment system uses stabilization ponds with groundwater discharge. When the Wisconsin Department of Natural Resources required the Village to upgrade its system, the Village called on Ayres Associates for assistance. Ayres completed a facility plan and identified expanded stabilization ponds as the preferred solution. This alternative provides a system that is similar to the current system in maintenance and complexity but can handle projected flows and protect the environmentally sensitive Upper St. Croix watershed.
The design expanded the existing 150-day storage ponds to 300-day storage to allow denitrification. The project required 300,000 cubic yards of excavation involving three ponds. The existing force main was replaced with directionally drilled fusible PVC. The project cost was funded through $1,541,000 in loans, a $727,000 American Recovery and Reinvestment Act grant, and a $1,092,000 U.S. Army Corps of Engineers Section 154 grant.