Charlottetown sees green in its sewage treatment options.
While its population base may be only 40,000 people, the capital of Prince Edward Island is swinging for the fences with ambitious plans to upgrade its treatment plant and turn it into a showcase for innovative energy and resource recovery technologies.
It announced plans in March and is exploring which options, such as solar and tidal energy, biogas recovery, sludge repurposing, geothermal energy extraction and co-generation, would work best with the scale and budget available.
"We know not everything is going to be affordable," says Charlottetown chief administrative officer Peter Kelly.
"But that doesn’t mean we shouldn’t look at everything."
The Level 4 Charlottetown Pollution Control Plant on Riverside Drive handles 20 million litres of raw sewage every day and is in line for an upgrade.
There’s also money on the table from all three levels of government.
The plant is adjacent to the Hillsborough River and treats the majority of wastewater from the city.
The expansion will also allow it to treat the wastewater from the nearby city of Stratford.
The wastewater from the East Royalty neighbourhood is treated via the East Royalty Lagoon but it is being decommissioned and the flow will come to the main plant.
The city is partnering with Carleton University’s Centre of Community Innovation on a Canadian Impact Infrastructure Exchange pilot project.
Also participating are Vancouver and Toronto.
The plan is to explore what options are available and what is best suited for each municipality’s needs.
The pooling of resources and sharing of details will go a long way in casting a wide net to gather as much information as possible, says Kelly.
The city is also partnering with the University of PEI’s School of Sustainable Engineering and Holland College to involve students in the research and development of ideas.
"We spend about $500,000 a year on energy costs alone so if we can reduce costs it would help," says Kelly.
"It would also cut 1,000 tonnes of CO2 from our carbon footprint. The federal government is paying half, the province and the municipality are splitting the balance."
The first round of infrastructure spending from Ottawa’s Clean Water and Wastewater Fund has earmarked $55.7 million for P.E.I. over three years.
There’s also $75 million for climate change initiatives and Kelly says the shoreline around the plant will also be beefed up.
"If we’re going to be investing millions into the plant, we need to protect our assets because sea levels are consistently rising," he says.
"So the shoreline will see some work too."
It’s early days yet and the project is in the planning stage, he adds, with consulting engineers CBCL expected to report back next spring with a menu of options.
Among them will be looking at adding photovoltaic solar panels to the roofs of buildings at the plant, but Kelly says they’re also looking beyond the site itself.
"We’re going ahead with solar panels on city property regardless," he says.
Other options for direct power include wind and tidal turbines in the Hillsborough River.
Wind could generate up to three megawatts, notes an initial report sent to council. The plant itself could be served by two megawatts.
Also up for discussion is a biogas co-generation system fed by the secondary digester which currently produces 750,000 cubic metres a year of gas used for heat and space heating. Excess gas is flared off.
The city is investigating the merits of installing a 130-kilowatt co-generator to run on biogas, producing another 500,000 kilowatt-hours annually for space heating and hot water.
They’re also looking at extracting energy through heat pumps from the 20,000 cubic metres of wastewater flowing daily which averages 10 C.
At only five per cent efficiency it would generate one megawatt a year, saving 100,000 litres of fuel.
The existing plant’s biosolids are highly rated and about 4,000 wet tonnes are removed by a contract for agricultural use.
Using sunlight supplemented by sustainable source energy, the city hopes to dry the biosolids further to 50 per cent and add value to the final product to further offset costs.
"We’re also looking at an atrium, like a greenhouse, where the public could come and enjoy the flowers and plants of a botanical garden," says Kelly.
"It would be serene with music perhaps and somewhere to come, especially in the winter when we don’t get a lot of sun."
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