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SEWAGE IN THE CRD: Added benefits to sludge plan

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

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.

B次元官网网址淚ntegrated resource management (IRM) is a realistic possibility right now and it could provide very substantial financial and environmental benefits to the region,B次元官网网址 said Vic Derman, the Saanich councillor who chairs the CRDB次元官网网址檚 IRM task force. He added those benefits could reach into the hundreds of millions of dollars. B次元官网网址淥bviously, if you can turn that waste into a revenue instead, itB次元官网网址檚 a considerable plus.B次元官网网址

The sewage committee recommended that staff investigate a facility for treatment of biosolids B次元官网网址 a fancy term for the sludge left behind after the treatment process.

B次元官网网址淭he wastewater plant takes most of the solids out of the water, treats the water and discharges it somewhere. All that sewage sludge that youB次元官网网址檙e left with has to be treated, because itB次元官网网址檚 pathogenic,B次元官网网址 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. B次元官网网址淚tB次元官网网址檚 a kind of resource recovery, but not a very efficient one,B次元官网网址 Atwell said.

Gasification process can create usable product

The need to deal with biosolids could be eliminated by gasification B次元官网网址 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 sludgeB次元官网网址檚 carbon content, leaving behind mainly inorganic ash.

B次元官网网址淵ou 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,B次元官网网址 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 projectB次元官网网址檚 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 B次元官网网址 construction plus lifetime operating costs B次元官网网址 of the plant to zero.

ThereB次元官网网址檚 even a potential for the region to make a profit through the sale of energy, he said. B次元官网网址淚f thatB次元官网网址檚 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. ThatB次元官网网址檚 a huge environmental benefit.B次元官网网址

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 hasnB次元官网网址檛 been tapped yet.

Derman said the potential savings from an IRM facility are simply too great to ignore. B次元官网网址淚f 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.B次元官网网址

Combining waste stream processing could extend landfillB次元官网网址檚 life

A solids treatment facility at Hartland landfill is a critical component in the Capital RegionB次元官网网址檚 solution to its liquid waste. But it will also have a major impact on the future of the regionB次元官网网址檚 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.

B次元官网网址淚t really depends on how much you put in it,B次元官网网址 says Derman, a Saanich councillor. B次元官网网址淚f 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.B次元官网网址

The sewage committee hasnB次元官网网址檛 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.

B次元官网网址淭o go from two trucks to five trucks at each outfall doesnB次元官网网址檛 seem to be that impractical to [justify] the cost of a $50-million pipeline plus the ongoing operating costs of pump stations,B次元官网网址 Isitt says. He suggested looking into electric trucks for the transport job.

B次元官网网址淓ven if, letB次元官网网址檚 say one of these trucks cost $1 million, I think you may see a financial benefit,B次元官网网址 he says, adding that option would eliminate greenhouse gases created with building a pipeline.

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