Due to high wet weather flows, operating this wastewater treatment plant had become challenging—and the state EPA required the City to address the issue. TWM performed flow monitoring at five locations to evaluate the infiltration/ inflow (I/I) of the five sub-basins and identify the problem areas. Using the flow data, TWM then developed several recommendations to upgrade the collection system and provided cost estimates for each and also proposed improvements to the City’s wastewater treatment plant. The new plant improvements, which will be completed in four phases, include a new biological treatment process, a new filtration system, a new disinfection system, and improvements to the solids treatment/handling systems.

Scope of Work

  • Planning for phosphorus and nitrogen limits

  • Upgrades to solids handling

  • Long-term planning for collection system

  • Sanitary sewer study


City of Troy, IL


Troy, IL


  • Flow monitoring at five locations
  • New biological treatment process
  • New filtration system
  • Improvements to solids treatment/handling systems


Treatment Plant