G. E. Booth Wastewater Plant Expansion

The Region of Peel’s expansion of the 45-year old G. E. Booth (Lakeview) Wastewater Treatment Plant in Mississauga, Ontario has increased its capacity from 336 ML/d to 448 ML/ d. The expansion makes it one of the largest wastewater treatment facilities in Canada. It serves Peel’s expanding population, which is projected to grow from its current 1.25 million to 1.57 million by 2031.

Engineers (formerly KMK/UMA) from AECOM Canada teamed with Black & Veatch to do the planning, detailed design, tendering, contract administration and site inspection services for the expansion.

The existing plant is a conventional activated sludge plant consisting of three separate treatment trains. The residual sludge was being treated through a thermal conditioning process that caused odours and drew in complaints from the adjacent neighbourhood.

Fine screening and fluidized bed biosolids incineration

The phase 1 expansion incorporates a consolidated headworks facility, which uses 6-mm diameter screens and is one of the first fine screen installations at a facility this size in Canada.

A new vortex grit removal process with covered tanks was added to replace aerated grit channels. The headworks has a dedicated odour control system that collects and treats odours from the incoming sewer mains and also from the screens and grit tanks. As well, a second odour control facility was provided for one of the three plants.

To meet the Ministry of Environment’s requirement for effluent at the end-of-pipe, a new secondary treatment process had to be added to remove ammonia by nitrification. For this, the Region initiated a full scale demonstration of the Integrated Fixed Film/Activated Sludge System (IFAS). This is an emerging technology that can be retrofitted into existing tanks, thus saving space and costs. The process involves adding biomass plastic media to the aeration tanks. The pilot demonstration began in 2004 in a 14,000 m3/d treatment train and is still being run.

After considering 11 alternative approaches to biosolids management, it was found that incineration is the most environmentally friendly and cost-effective solution, and it produces the least odours. Accordingly, the plant will eventually have four fluidized bed incineration units with processing capacity of 100 dry tonnes a day each. Two are now operating, and when all four are commissioned, the plant will be the largest fluidized bed solids incineration facility in the world. The incinerators burn dewatered sludge cake in a pre-heated fluidized sand bed reactor. The by-products are inert ash, water vapour, and exhaust gases. The “hot windbox” design reuses the exhaust energy to pre-heat the fluidizing and combustion air. The heat exchange, coupled with the heating value inherent in the dewatered cake (minimum 28% dry solids), allows the incineration process to run autonomously, without the need for auxiliary fuel.

Another strategy was to combine in one building the waste activated sludge (WAS) thickening centrifuges with the biosolids dewatering centrifuges. Co-locating the processes gives operation and maintenance efficiencies. Also, with the added thickening capacity, the process does not require polymer, which saves up to $500,000 annually.

The plant’s electrical system and SCADA systems were upgraded to enhance their reliability and operability. A new centralized control room services the whole site.

The project was so large and complex it was broken into 10 construction contracts. This approach enabled more contractors to bid and resulted in more competitive tender prices.

Designing and consolidating so many elements and their infrastructure within the tight site required careful planning. At some point over the duration of the project, every facet of the plant was affected by the construction. The project was completed over four years in December 2007, on time, and for a cost of $250 million.

Name of project: G. E. Booth (Lakeview) Wastewater Treatment Plant Expansion and Upgrades, Mississauga, Ont.

Award-winning firm (prime consultant): AECOM (Deborah Ross, P. Eng., Bob Fleeton, P. Eng., Troy Briggs, P. Eng., Peter Bradley, P. Eng., Rick Dray, P. Eng.)

Owner: Regional Municipality of Peel

Subconsultant (design): Black & Veatch Canada (Jim Welp, PE, Frank Dachille, PE, Sean Partington, P. Eng.)

Other key players: B. J. Tworzyanski (electrical), CS & P Architects (architecture), AMEC Earth & Environmental (materials testing), Dakins Engineering Group (SCADA), Hardy Stevenson & Associates (public facilitation), Durham Energy Specialist (HVAC/plumbing)

Supplier: John Meunier (escalator fine screens)