Client: Regional Municipality of Waterloo
Location: Cambridge, Ontario


The Hespeler WWTP is an extended aeration facility with a rated average day flow capacity of 9,320 m3/d and a peak flow capacity of 19,850 m3/d. The Hespeler WWTP has experienced operational problems in the past several years that prompted the Region to undertake a thorough plant review. This review identified some operational and capacity issues and recommended short and longer term upgrades to the works.

XCG, in association with another firm, were retained by the Region to develop the Preliminary Design of the short-term upgrades to increase robustness of the treatment process as Phase 1 of the project. Phase 2 of the project, to be undertaken in the future, involves the design and implementation of long-term upgrades to provide additional servicing capacity. The following tasks were completed as part of this study:

  • Review the historic performance and existing capacity of the Hespeler WWTP;
  • Development of a conceptual level design basis for Phase 1 and Phase 2;
  • Development of conceptual level design options for Phase 1 – Short-term Upgrades, and recommend the preferred option; and
  • Resent conceptual level design options for Phase 2 – Long-term Expansion.

Treatment technologies considered as part of the evaluation included extended aeration, conventional activated sludge (CAS), membrane bioreactor (MBR), and integrated fixed-film activated sludge (IFAS). Where applicable, alternative waste activated sludge (WAS) handling options were considered, including co-thickening and separate thickening.

Based on the results of the evaluation, the selected preferred option for Phase 1 was: Upgrade the Existing Extended Aeration Process. This option included modifications to the existing sludge holding and aeration tanks to provide a plug-flow aeration basin complete with tapered aeration, construction of a new aeration basin, and upgrades to secondary clarification.

Mike Newbigging
Mike NewbiggingSenior Project Manager


Contact Mike for help with your Wastewater Treatment related project.