Introducing the New St. Mary Water Treatment Plant
The District must build a new treatment plant on St. Mary Lake for four key reasons:
- The current plant is at the end of its useful life and is no longer capable of meeting Island Health’s drinking water standards. As the largest of 15 island water districts, NSSWD supplies the over 50% of island residences and business, schools, hospital, and the assisted living facilities. The current plant is not able to meet all water quality regulations which could negatively impact the community’s health.
- In the case of another toxic cyanobacterial bloom, the current treatment may not be able to remove toxin in the treated water which would render the water undrinkable for the duration of the bloom as chlorine is only effective against certain types of toxin.
- Without the DAF process we cannot remove organics that combine with chlorine to form potentially carcinogenic by-products in our treated water. Current levels of trihalomethanes and haloacetic acids are sometimes above health guidelines.
- In 2008, the Vancouver Island Health Authority (VIHA, now Island Health) amended NSSWD’s operating permit mandating that NSSWD construct a Dissolved Air Floatation (DAF) Water Treatment Plant by 2011 to comply with current and future drinking water standards as per their 4-3-2-1 Policy. Island Health extended the original deadline requiring the plant be commissioned by January 1st 2016 — The District is still using this as our target date but a further extension may be required.
How did we get here?
The North Salt Spring Waterworks Improvement District was incorporated as an Improvement District in 1948 with the purchase and amalgamation of the Ganges Water and Power Company and the Vesuvius Bay Water System. At this time, all water was withdrawn from Maxwell Lake and delivered to Ganges and points north via a system of water mains, pressure regulating valves, pumps and reservoirs.
Around 1967, as the community continued to grow, the District Board of Trustees had to make a decision on the best approach to meet the increasing demand. Would it be more cost effective to upgrade the water main from Maxwell Lake or to develop St. Mary Lake as a community water source? The ratepayers voted resoundingly against the St. Mary option preferring the better quality water from Maxwell Lake.
42 Years Ago
By 1970-71 further engineering studies strongly recommended that the District start withdrawing water from St. Mary and install a sand filter and chlorination system for treatment. Initially providing ~210,000 imperial gallons/ 955m3, Phase #1 of the St. Mary Treatment Plant was built on the present Tripp Road site and became operational in 1973.
In 1982, Phase #2 was built and increased the plant capacity to ~600,000 imperial gallons/ 2727m3. Over the years, equipment has been upgraded, changed or added but it is essentially the same treatment plant some 42 years later.
Over the years the distribution system has also expanded and now reaches north to Southey Point and up to Channel Ridge, putting further demands on the St. Mary Plant.
More Stringent Regulatory Guidelines
Over these same years, water quality regulations continued to be strengthened and enhanced to better protect the public health. The Canadian Guidelines for Drinking Water Quality, published by Health Canada, establishes benchmarks for microbiological, chemical, radiological and physical water quality parameters. All guidelines are based on current, published scientific research, and are widely accepted and used by all provinces and territories for establishing enforceable regulatory requirements. In BC, The Drinking Water Protection Regulation dictates regulatory requirements for E. coli, and total and fecal coliform bacteria.
By 2008, the St. Mary Treatment Plant was no longer capable of meeting future demand (with a respectable safety margin) and the raw lake water, which had become subject to severe algal blooms, was continuing to degrade. It was determined by Island Health that the plant was unable to fully meet current water quality guidelines or the expected more stringent future regulations.
In 2003, the BC Drinking Water Protection Act came into effect. The Act requires that all water suppliers provide potable water and gives Island Health the responsibility for monitoring compliance with the Drinking Water Protection Act. As a result, Island Health’s 4-3-2-1 Policy was brought into effect. The 4-3-2-1 policy is based on the Multi-Barrier Approach to Safe Drinking Water recommended by Health Canada. It was developed as a performance target to ensure water suppliers were meeting the legislated requirements and has been applied to existing treatment systems since 2007. For treatment of St. Mary Lake water, Island Health has specifically mandated installation of a Dissolved Air Floatation (DAF) Plant to meet present and future drinking water regulations.
Looking to the Future
With all this knowledge at hand, the District’s Board of Trustees set about reviewing and adjusting the Districts’ parcel tax and water toll rate structures to begin building a Capital Projects Fund over and above operations costs. This has been reasonably successful but is still a long way from the cost of a new treatment plant.
In conjunction with these events, the Board and Staff began a review of consulting engineers in BC with experience in designing water treatment plants. This process ultimately led to the commissioning of Kerr Wood Leidal Consulting Engineers (KWL). KWL have designed numerous water treatment projects of comparable size and scope throughout BC.
Where Are We Now?
KWL completed the detail design in February 2015.
The projected cost for the detailed design, building construction, equipment and infrastructure upgrades is estimated to be $8.9 million. The cost of the Detail Design has been paid from the District’s reserve funds. Up to $8.4 million will be financed. Final costs will be determined once the project tenders are received and a contractor selected. The building will be a post-disaster rated, concrete structure, built into the side of the hill on the current site which will house the DAF process trains, ancillary equipment and a small office/lab. Processed waste and finished water will be stored underground. It will provide quality drinking water with a much improved taste.