Project Update: Corbett Creek WPCP - Digester Facilities Upgrades

Monday, 26 March 2018

The Corbett Creek Water Pollution Control Plant (WPCP), located in Whitby, Ontario, is a secondary treatment facility that utilizes a conventional activated sludge process for sewage treatment and anaerobic sludge digestion for stabilization of wastewater sludge. Kenaidan constructed a new Primary Digester, converted an existing Secondary Digester to a Primary, and constructed a new gas building, heat exchanger room, and various upgrades to the Digester Control Building.

The scope of work encompassed demolition of the existing Digester No. 1 system, sludge piping, gas, and heating systems. This was replaced with new piping, valves, pumps, heat exchangers, and related equipment. The entire digester gas system was replaced with new gas boosters and safety equipment. The new boilers are dual fuel, which can be powered by digester gas or natural gas. The work also included piping and mixing systems for the newly constructed digester.


Kenaidan self-performed all concrete formwork and placement, as well as process mechanical installations. Construction began in the summer of 2016 and was substantially complete April 3rd, 2018.

Contract Services:  Stipulated Lump Sum

Concrete: 1,370 m3

Formwork: 2,748 m2

Project Features:

  • A new 26 m diameter, reinforced concrete Primary Digester
  • Modifications to an existing digester
  • Digester gas room
  • New sludge heat exchanger/pump room
  • Expansion and modifications to existing digester control building
  • Provision of new equipment, including boilers, heater exchangers, pumps, gas boosters, and valves
  • Modifications to process and gas piping systems
  • Provision of new digester gas safety equipment
  • Upgrades and modifications to HVAC, mechanical and electrical systems
  • Provision of control and instrumentation including SCADA system
  • Landscaping works

Key Challenges:  

  • Maintain Primary Digester No. 2 in service with no interruptions to the plant operations while completing the new gas room and installing the new gas lines
  • The mechanical team managed to avoid multiple shutdowns that were set to be performed within 24-hour windows, which
  • were both costly and timely, by proposing a solution to bypass sludge recirculation lines, sludge transfer lines, raw sludge lines, and scum lines in a 48-hour window; this allowed additional works to take place that would not have been feasible otherwise, as it would directly impact the day-to-day operations for weeks
  • Completion and certification of the new gas room prior to completing roof top and HVAC works
  • Supporting live process piping, gas piping, and other site services during construction
  • Performing tie-ins and shutdowns without impacting ongoing operations