Upgrade and Modernization Transformers Wastewater Into Clean Water
By Tina Costanza
If there’s one thing the citizens of Dieppe, Moncton and Riverview are passionate about, it’s the Petitcodiac River that flows through that tri-community in New Brunswick. It’s where residents and visitors enjoy recreational activities, such as surfing the tidal bore, boating and fishing. It’s also the destination of the flow from the TransAqua Wastewater Treatment Facility in Riverview.
Clearly, it’s crucial the facility does its job well — clean water in the river supports tourism, protects public health, and ensures the river remains a source of recreation — and TransAqua has been upgrading and modernizing the facility.
The work stems from the CCME (the Canadian Council of Ministers of the Environment) having deemed the facility in 2010 to be at high risk under its new guidelines for their effluent regulations, explains Kevin Rice, General Manager of TransAqua and responsible for delivery of the Wastewater Treatment Facility Upgrade and Modernization Project. TransAqua then had 10 years, to Dec. 31, 2020, to meet the guidelines.
The governments of Canada and New Brunswick pitched in to help. Each has contributed $22.6 million to the $90.4-million project. TransAqua is providing the remaining funds.
The improvements will also stabilize the wastewater treatment rate and create pre- and post-construction jobs. Sixty-five contractors have been working at the site this past spring. The average number of workers throughout the year ranges between 40 and 60, depending on what’s going on at the time. Come July 2020, Rice says TransAqua estimates about 100 contractors will be on-site for a few months.
The workers will be upgrading the chemically enhanced primary treatment process to a secondary biological level wastewater treatment system that can serve a growing population.
“We currently service 118,000 citizens, with an average daily flow of 71,000 cubic metres,” Rice says. “Because our communities are growing — the city of Dieppe was one of the fastest growing communities in Canada the last few years — our upgrade design is factoring in 147,000 citizens, with an average daily flow of 90,000 cubic metres.”
Other factors include allowances to meet future combined sewer overflow treatment guidelines, and redundancy and equipment, so preventive work and maintenance can be carried out while equipment is taken down.
Phases outline project milestones
TransAqua, the Greater Moncton Wastewater Commission, was established in 1983 to support the wastewater collection and treatment needs of Dieppe, Moncton and Riverview. It has also become a leader in the reuse of biosolids through the generation of type “AA” compost (the highest grade currently achieved in Canada) as opposed to disposal in a landfill site.
The upgrade and modernization project consists of five phases, and it’s now in phases 3, 4 and 5, specifically phase 3A, 3B, 3C and 4A. Phases 1 (preliminary treatment) and 2 (primary treatment) are complete. Phase 3A consists of the bioreactor, phase 3B is the blower building, phase 3C is the secondary clarifier, phase 4A is solid handling, phase 4B is the biosolids load-out facility, phase 4C is the bio filter, and phase 5 is UV disinfection.
Rice provided a rundown of the work that has been completed to date.
In terms of the bioreactor, 21 of 36 walls are complete. The slab, service tunnel, effluent supply channel and return channel, and the north and south access galleries to the bioreactor are complete.
In the blower building, ventilation, duct and electrical work in the basement are finished. The backup power generators and five blowers are in place, ready for electrical and mechanical connections.
Other work that has been done includes the expansion of the secondary clarifier electrical building, the relocation of a water main, the construction of secondary clarifier 4 and three sludge tanks, equipment replacement in secondary clarifiers 1, 2 and 3, the installation of the HVAC system, two rotary drum thickeners, the polymer system, domestic water system and piping, and the mechanical upgrading of three 30-year-old centrifuges.
“The existing centrifuges are designed to handle primary sludge, which is much thicker than secondary sludge, so we had to do some mechanical upgrades to change the insides of it to be able to handle secondary sludge,” says Rice. “If we didn’t do that, it would tear the sludge to bits, so it wouldn’t be any good to us.”
To help reduce power consumption, variable frequency drives will be installed on the back drives.
The team is now installing a larger generator and is building a waste-activated sludge box while design work continues on the UV disinfection, a bio filter and sludge load-out facility.
“We’ve got a lot of work left to do,” says Rice. “We’re really starting to ramp up again with the nice weather.”
Meeting and BEATING challenges
A project of this scope is not without its challenges, but the team members have foreseen and overcome them. For example, they set up a dome so they could build the sludge handling building and blower building under a cover during the winter months. This saved about eight months on the overall construction schedule.
They have also had to accommodate a facility that is still in service. Workarounds include planning power outages during low-flow times, and designing and building a diversion channel.
“While they were building the primary clarifiers we were able to keep the plant running by installing the diversion channel to keep the flow moving,” Rice says.
The big challenge, however, turned out to be a positive, says Rice. A general contractor had completed work on phases 1 and 2 in September 2019, and at that point Rice’s team took over the reigns, now working directly with a number of major local contractors.
“We said, ‘We’re going to handle this project ourselves,’” says Rice. “We basically had to move from a typical ‘design, tender, construct’ process to a ‘design, build-on-steroids’ process. We were pushing on the design phase and basically saying ‘as soon as you get that basement designed, we’re starting to dig a hole. And as soon as we’re digging a hole for the basement, you’re designing the building structure.’ We were really kind of pushing them and there’s a risk, because some things get missed.”
The issue that then cropped up was Rice’s team consisted of only 17 people.
“So we seconded two people on our staff. One was our wastewater systems engineer and our lead operator. So we seconded them to be the project manager and the construction manager.”
The move paid off.
“It’s been nothing but success,” says Rice, who adds the project is on time, despite the COVID-19 pandemic.
Dealing with the COVID-19 pandemic
“We proactively shut down the construction site from March 23 to April 12. We notified our funding partners and we developed — and the commission board approved — the pandemic policy and a construction site pandemic protocol,” says Rice.
“We just shut down for three weeks, put all our ducks in a row, got all the contractors on side before we reopened and it’s been nothing but a positive experience. We had been pushing our contractors pretty hard up until that point so we had a little bit of leeway. We could handle three weeks shutting down and be able to pick up where we left off and not endanger the schedule too much. So we will be on time and we’re projecting to be on budget, if not under budget.”
While the project hasn’t involved any formal community consultations per se, TransAqua has been communicative with stakeholders. The organization makes an annual presentation to the cities of Moncton and Dieppe and the Town of Riverview, and also periodically to provide them with a project update.
Before construction began, TransAqua mailed residents who live near the facility, to inform them about the upcoming work that could generate dust and noise.
Ratepayers, who have also seen an annual increase of about $5 since 2005, had the opportunity to attend an open house at the facility in 2019 and can view the work on a webcam on TransAqua’s website, transaqua.ca.
“We haven’t heard a single complaint,” says Rice.