Vic Derman

SEWAGE IN THE CRD: Added benefits to sludge plan

Part 4 of 5: Biosolids processing could recover costs for sewage program

The construction of a new sewage treatment plant for the Capital Region promises to be a costly endeavour. But another recommendation being weighed by the core area liquid waste management committee has the potential to balance off some of the costs.

“Integrated resource management (IRM) is a realistic possibility right now and it could provide very substantial financial and environmental benefits to the region,” said Vic Derman, the Saanich councillor who chairs the CRD’s IRM task force. He added those benefits could reach into the hundreds of millions of dollars. “Obviously, if you can turn that waste into a revenue instead, it’s a considerable plus.”

The sewage committee recommended that staff investigate a facility for treatment of biosolids – a fancy term for the sludge left behind after the treatment process.

“The wastewater plant takes most of the solids out of the water, treats the water and discharges it somewhere. All that sewage sludge that you’re left with has to be treated, because it’s pathogenic,” said Saanich Mayor Richard Atwell, who also sits on the task force.

The IRM group has looked at a number of ways to deal with that sludge. Anaerobic digestion uses bacteria to consume organic solid materials in an oxygen-free environment. This process produces methane gas, which can be used as a fuel source, reducing the amount of sludge by up to 50 per cent.

But that would still leave the CRD with up to 15 tons of biosolids to dispose of daily. “It’s a kind of resource recovery, but not a very efficient one,” Atwell said.

Gasification process can create usable product

The need to deal with biosolids could be eliminated by gasification – a process that uses high temperatures to convert organic materials such as wastewater sludge, wood waste, food scraps and municipal solid waste into a mixture called syngas, which could be used to fuel an electric generator. The process eliminates up to 90 per cent of the sludge’s carbon content, leaving behind mainly inorganic ash.

“You could probably, in some cases, be able to put [the ash] in a road bed or mix in with concrete. At the very worst, you would put it in Hartland and reduce what you put in by 90 per cent,” said Derman.

Current cost estimates outline an anaerobic digestion facility at Hartland at a cost of $258 million. However, Derman suggests the costs of a gasifier would be around $100 million. The treatment project’s technical oversight panel has recommended using gasificaton for solid waste processing, with Hartland landfill being the preferred site.

The committee is still exploring the options of whether the biosolids would be sent to Hartland through pipes or by truck.

The ability to generate energy through processing biosolids promises to greatly reduce operating costs for sewage treatment.

Derman said potential providers have suggested they could reduce the lifecycle cost – construction plus lifetime operating costs – of the plant to zero.

There’s even a potential for the region to make a profit through the sale of energy, he said. “If that’s true, you would further reduce the impact on the taxpayers. The other huge plus is when you use all these resources to replace energy coming from fossil fuels, you have a very substantial climate change mitigation factor. That’s a huge environmental benefit.”

Pivotal IRM, one potential provider, estimates that using the gasification process could provide the equivalent of removing 24,000 cars from the road.

The potential for significant environmental benefits and the use of innovative technology is something Atwell believes could qualify an IRM facility for new federal grants, pointing to $950 million in an innovation fund that hasn’t been tapped yet.

Derman said the potential savings from an IRM facility are simply too great to ignore. “If we get the federal government and province to participate on a one-third, one-third, one-third basis, the cost to local taxpayers becomes no more than what we put into [Royal] Jubilee Hospital.”

Combining waste stream processing could extend landfill’s life

A solids treatment facility at Hartland landfill is a critical component in the Capital Region’s solution to its liquid waste. But it will also have a major impact on the future of the region’s other municipal waste.

The two-plant option outlines a $258-million anaerobic digestion facility at Hartland to treat biosolids left behind from the treatment process.

Vic Derman, chair of the integrated resource management task force looking at options, says a gasification facility would prove much more efficient, at a greatly reduced cost. Not only would gasification eliminate the biosolids, he says, it could also stretch out the viability of the dump.

“It really depends on how much you put in it,” says Derman, a Saanich councillor. “If you do start to process some of the municipal solid waste that would go into [the landfill] otherwise, you probably pretty dramatically extend the lifespan. Instead of looking at 30 or 40 years, you might be looking at 100 years or more.”

The sewage committee hasn’t settled on the final treatment method for biosolids, how that material would be transported to Hartland, or even whether the biosolids processing facility will be located there.

Estimates put the conveyancing costs to transport solids to Hartland at $48.3 million. But committee members are far from convinced that piping is the best method of moving biosolids from the sewage treatment plants to a processing facility.

Victoria Coun. Ben Isitt wants to see a detailed financial analysis comparing trucking with piping. Two truckloads of screenings are currently taken from Clover Point to the landfill every week. Derman said the addition of biosolids would likely increase that frequency to two or three trucks a day per facility.

“To go from two trucks to five trucks at each outfall doesn’t seem to be that impractical to [justify] the cost of a $50-million pipeline plus the ongoing operating costs of pump stations,” Isitt says. He suggested looking into electric trucks for the transport job.

“Even if, let’s say one of these trucks cost $1 million, I think you may see a financial benefit,” he says, adding that option would eliminate greenhouse gases created with building a pipeline.