Designing a water treatment solution for a rural First Nation community
Alderville First Nation, a small community located approximately 90 miles east of Toronto, Ontario, Canada, has taken an important step toward improving its on-reserve water quality. As one of a select number of Ontario First Nation communities to pilot innovations to improve water supply, Alderville installed a system of water softeners and point-of-entry (POE) ultraviolet (UV) potable water treatment systems to deliver safe water to its residents.
The project, with the goal of ensuring access to improved water quality, is part of the Canada-Ontario First Nations Pilot to Improve Drinking Water Quality program, a joint initiative of the governments of Canada and Ontario and the Ontario First Nations Technical Services Corp. (OFNTSC). In 2012, the government of Canada provided up to $5 million Canadian in funding to cover capital infrastructure costs and three years of operations and maintenance for the projects. To qualify for pilot support, projects had to demonstrate lack of a communal drinking water system or a high design risk in earlier assessments.
Analyzing the Challenge
The challenge for the Alderville project was developing a system to address the varying water quality in wells for 33 homes and buildings spread across a large geographic area with no access to public water supplies. Alderville First Nation, with assistance from the OFNTSC and the Ontario Ministry of the Environment and Climate Change, selected Arcadis, an international engineering design and consulting firm, as principal engineering consultant and general contractor on the $1.5 million Canadian project.
In its extensive water quality analysis, Arcadis discovered a wide variation in water quality based on different site and soil conditions, water hardness and groundwater levels. Treatment systems had to be designed to accommodate these variables in a cost-effective manner.
The cost of building a central treatment plant and network of distribution pipes to serve the entire community eliminated a new public system as an option. Instead, Arcadis specified individual POE UV systems to be installed at each location.
The construction plan included a community liaison to provide communication to address concerns and provide status updates throughout the project. The team conducted a thorough photographic and video survey of all the properties before and after construction to ensure all 29 homes were restored to their original condition.
A rigorous and comprehensive health and safety plan provided a safe working environment throughout construction activities. As a result, no time lost or injuries were reported during construction.
The mechanical filtration and softening systems minimize maintenance, energy consumption and process waste. The water softeners do not use clocks, electric valves or electric sensoring devices to regulate regeneration. Instead, the systems use a mechanical flow metering mechanism, which regenerates the system based on the volume of consumed water. Not only does this reduce process waste and salt consumption, it also requires less attention from the homeowner while meeting the requirements of NSF/ANSI Standard 44.
The Hallett UV system provided by UV Pure has a minimum UV dose of 40 mJ per sq cm, and is designed to achieve 4-log removal of Cryptosporidium, Giardia and viruses. The NSF/ANSI Standard 55 Class A-certified Hallett 15xs exceeds Ontario’s Provincial Water Quality Objectives standards of 2-log Cryptosporidium, 3-log Giardia, and 4-log virus removal for groundwater under the influence of surface water.
The UV system requires little maintenance and features an automatic self-cleaning system that prevents build-up of minerals on the quartz sleeves. The system also is engineered to reduce space requirements and make the occasional UV lamp change easy to perform.
Ease of Use
As a precaution, Arcadis developed an operation and maintenance manual to support ongoing operation and trained local operators in troubleshooting and maintenance. For the 12 months following completion of the project, Arcadis engineers will be conducting operations and maintenance and will be on call to assist with any issues.
The UV systems’ smart sensors provide continuous monitoring and trigger an alarm to notify the owner and shut down the system if bacteria or viruses exceed recommended ranges.
The UV systems remove Cryptosporidium, Giardia and viruses from the water.
The final design included an insulated, heated enclosure shed to house the water softening, filtration and disinfection equipment for each home. Careful siting of each enclosure shed minimized the construction footprint and used as much existing infrastructure as possible. A typical enclosure is insulated with 4-in. polyurethane foam delivering a total R-value of 20 and features roof pitches to match those of the house.
Cedar was used to enclose a permanent shed to house water treatment units at each home.
Careful planning and engineering delivered the project on time and on budget. Thanks to the thoughtful approach, the households of Alderville First Nation enjoy safe, quality drinking water.
While it can be challenging to deliver clean, safe drinking water in rural locations like Alderville First Nation, this project shows it can be done. One of the strengths of this solution is its simplicity, coupled with proven technology and technical support during the implementation of the systems.