TWM provided the complete design of this treatment plant expansion, from facility planning through construction phase engineering, increasing design capacity over 50%—from a daily average flow of 8.0 MGD to 12.4 MGD. The project included a new 200 MGD pump station and modifications of existing sludge storage lagoons into storm management basins, and a counter current aeration system for both energy savings and nutrient removal, UV disinfection, and conversion of existing anaerobic digesters to autothermal thermophyllic aerobic digestion. As part of the digester conversion, TWM provided a 3D scan of the existing congested piping building so that precise locations for all interior piping was known.

Structural design included concrete tanks, slabs, CMU buildings, foundations, platforms and walkways, and a pipe bridge.

TWM prepared the facility plan, new user charge system, IEPA permits, bidding documents, and performed construction observation for the project. All buildings and processes were designed so that future additions to the plant can be quickly and easily integrated. TWM worked with the City to develop a suitable schedule of user charge increases. SRF funding.

The surveying scope also included topographic and boundary surveys in addition to as-built drawings of existing facilities that were modified or impacted by design.

Scope of Work

  • Large scale treatment plant design

  • Repair and modification to existing tankage

  • Repurposing of existing lagoon


City of Belleville, IL


Belleville, IL


  • Design included chemical feed equipment, tanks, piping modifications, and pumps
  • Counter current aeration system boosted energy savings


Water Infrastructure