Critical long-term wastewater infrastructure questions are being asked at the CVRD, among them: Should sewer pipes come out of the K’omoks Estuary? What level of treatment do we want, and how will we meet the long-term growth of the Comox Valley? And, should we be planning to recover our wastewater resource?
This article was updated Nov. 9
Just over a year ago, the Comox Valley Regional District stepped back from plans to patch the existing sewer service, which serves only Courtenay and Comox, and take time to consider how best to meet the long-term needs of a growing Comox Valley population.
That process got underway this summer with public consultations that have included in-person meetings, an online survey and two open houses held this week at the treatment plant.
Planning is focused on three main areas:
First, how best to collect and convey wastewater to the Comox Valley Water Pollution Control Centre on Brent Road, near Point Holmes.
The main pipe carrying sewage from the Courtenay #1 pump station next to Kus-kus-sum site on Comox Road, currently runs through the K’omoks Estuary and Comox Harbor, under Goose Spit and along the beach below the Willemar Bluffs before turning inland a short distance to the Brent Road plant.
CVRD engineers and an Public Advisory Committee will consider other options for moving wastewater to the treatment plant, including overland routes that would reduce risk to the K’omoks Estuary. The committee includes eight public members, plus three elected officials and representatives from industry and stewardship sectors.
Second, what level of treatment should be provided at the treatment plant now, and a long-term plan for meeting both evolving land-use planning standards and the needs of geographical areas beyond the boundaries of Courtenay and Comox.
The existing plant meets or exceeds all provincial and federal standards, but does not provide tertiary level treatment. It doesn’t directly treat for nitrogen, pharmaceuticals or heavy metals.
Nor does it treat wastewater to a standard that can be safely used for agricultural irrigation, golf courses or other non-potable uses, such as groundwater reinjection.
Some communities around North America and elsewhere already treat wastewater to a level that it is directly re-introduced into their drinking water systems.
Third, how to incorporate resource recovery options, and its cost, into this long-term planning process.
For example, if upgrades to the treatment plant produced effluent safe for agricultural uses and a new, overland conveyance route was chosen, a new pipe carrying the highly cleaned wastewater could be laid at the same time back to the Courtenay #1 pump station.
Interesting wastewater facts
During this week’s open houses, employees of the treatment plant toured dozens of citizens through the facility. Here’s a random collection of facts and observations from one of those tours.
— The CVRD spent about $2 million retrofitting the plant to mitigate the odour problems that have plagued nearby residents for decades. Permanent covers over the primary clarifiers and a high-tech activated carbon polisher have reduced odours.
But when major community events, such as MusicFest, occur and the volume of waste dumped into the system via septic pumping trucks, the density of the sewage can create a spike in odours. For that reason, these volumes are held and processed during the nighttime when regular residential flows have diminished.
–In the summer months, it takes about 24 hours for sewage to travel from the Courtenay #1 pump station to the treatment plant. But in the winter, when rain water infiltrates the sewer lines, it flushes through much faster, in about 8 hours.
— It takes about one day for wastewater entering the treatment plant to exit to the Point Holmes outfall.
— Effluent travels via gravity only from the treatment plant to the outfall, which is located at the sharp curve in Lazo Road up the Point Holmes hill. The outfall extends 3 km at a 45-degree angle into the Strait of Georgia and terminates at a depth of 60 metres.
— The treatment plant was designed in 1983 and has a permitted maximum daily discharge of 18,000 cubic meters of wastewater per day, and averages about 14,000 cubic meters. The daily average goes down to about 12,000 cubic meters in the summer. In the mid-2000s, the plant started to exceed its maximum daily discharge during peak wet weather events, and now exceed the permitted discharge approximately 30 times per year. Those numbers are reported to the Ministry of Environment.
But in the winter, the volume of wastewater flowing through the plant reaches more than 40,000 cubic meters per day. The increase, which is more than three times the summer average, is due to rain water from winter storms infiltrating the system.
— The treatment plant has a laboratory where testing occurs daily for the quality of effluent leaving the plant, the heaviness of solids entering and the population of aerobic bacteria present during the aeration process that degrade the pollutants for their growth and reproduction.
— The first step in treatment process screens out all the rags, paper, plastic and metals that have been flushed into the sewage pipes. The plant removes a full dumpster load every week.
— Not all solids are removed from the wastewater before it’s discharged into the Strait of Georgia, but most of it. About 3,000 kg of solids enter the plant every day. The discharged effluent contains about 75 kg per day.