TWM prepared a facility plan and designed the expansion of this plant from a design capacity of 2.7 to 5.0 MGD, an increase of 85%. TWM performed flow monitoring for an inflow / infiltration study of 10 sub-basins, an assessment of the lift stations, growth and flow projections for the system, and an evaluation of treatment technologies, including Membrane Bio-Reactor, Extended Aeration, and Sequencing Batch Reactor. Each alternative treatment was evaluated based upon initial costs as well as future maintenance requirements.

The project included a new sludge handling facility, conversion of the existing extended aeration tanks to sequencing batch reactors with provisions for biological nutrient removal, a new office and laboratory, and a new headworks and terminal lift station. The plant’s original ultraviolet light disinfection system—designed by TWM as one of the first such municipal systems in the state—was also upgraded as part of the expansion. Previous expansions and improvements were designed by TWM in 1983 and 1995. SRF funding.

Scope of Work

  • Re-use of existing tanks

  • Biological nutrient removal

  • Long-term collection and treatment system planning

  • Sanitary sewer study


Village of Swansea, IL


Swansea, IL


  • Design capacity increased 85%, from 2.7 to 5.0 MGD
  • TWM’s design of the plant’s original UV light disinfection system – one of the first such municipal systems in the state – was upgraded as part of the expansion


Treatment Plants