A trio of University of Victoria mechanical and electrical engineers explain in their April 16 commentary that we need land-based sewage treatment because 鈥渢here is too much uncertainty and thus too much risk for us not to take action 鈥� . No one really knows the fate of the contaminants that are continuously discharged into the Salish Sea.鈥�
Should these be the reasons for聽the Capital Regional District to spend an estimated $783 million on land-based sewage treatment? Surely there should be measurable harm to the marine environment and a quantifiable benefit before spending this vast amount.
The current treatment works were designed by civil engineers and are accepted as practice by the World Bank for unique receiving environments. The unique situations are where sewage is assimilated into and treated naturally by the marine environment.
Victoria鈥檚 sewage (which is 99.9聽per cent water) is screened to six millimetres and discharged through two deep-sea outfalls more than a kilometre from the shoreline and sixty metres below the ocean surface. At the end of the outfalls are 70-metre diffusers.
The CRD has a world-class source-control program that eliminates many substances (such as fats from food premises, mercury from dental offices and used pharmaceuticals).
The current preliminary treatment has been extensively monitored and studied by the CRD and reviewed by marine scientists. It has been shown to produce a minimal effect on the ocean floor.
There is no question that there are uncertainties about the fate of the chemicals of concern and even micro-plastics. However, just because substances can be detected (and with today鈥檚 scientific instruments they can be detected in minute amounts 鈥� parts per trillion or quadrillion) does not mean there has been an effect at very low levels.
When a substance is detected, there is, however, a perception of聽an effect that might not have聽been determined.
The credible judgment of marine scientists, public-health officials and engineers that the current discharge of the screened effluent into a unique marine receiving environment is highly effective has largely been ignored. Nine of the 10 marine scientists are from the University of Victoria. Have the mechanical and electrical engineers reviewed their judgments and recommendations?
Here are some questions that should be answered before spending more on land-based sewage treatment for Victoria.
鈥� What are the current or potential problems with wastewater and other discharges into the local marine environment?
鈥� How serious are these problems?
鈥� What are the major sources of the problems?
鈥� Will a proposed remedy eliminate or even reduce the problems without creating bigger impacts?
鈥� Are there better solutions than the ones proposed?
鈥� Is addressing the problems a high priority for marine environmental protection?
The mechanical and electrical engineers make no mention of the聽environmental impacts of land-based sewage treatment plants. These plants and their connecting pipes will have an effect on the land and global environments.
The treatment process increases the solid matter and produces sludge that then has to聽be disposed of by an undetermined means. Hundreds of tonnes聽of concrete will be used. Concrete is made with cement, and producing one tonne of cement produces one tonne of carbon dioxide, a greenhouse gas聽that contributes to global climate change.
It was estimated by consultants to the CRD that building the proposed land-based sewage treatment plants will produce 15,516 tonnes of carbon dioxide equivalents, or greenhouse gases. During operation, the carbon dioxide emissions are estimated at 7,917 tonnes per year.
If the overall environment is considered 鈥� marine, land and global 鈥� there will be more harm than the minimal contamination from the current practice of discharging the preliminary treated sewage into the marine environment.
There is currently a political impasse 鈥� Esquimalt council has refused to rezone the McLoughlin Point site for a sewage-treatment plant. The B.C. government has declined to be involved. This presents an opportunity to rethink the whole project and to take notice of the science that supports the present practice.
The CRD needs to challenge the federal wastewater systems effluent regulations and the provincial environment minister鈥檚 2006 order to develop a sewage-treatment plan. The challenge should be based on the vast amount of evidence that is available from UVic marine scientists and the judgment of public-health officials.
Dr. Shaun Peck was the medical health officer for the CRD from 1989 to 1995.
