New subdivision development within the Town of Gander caused low chlorine residuals in the northwest land assembly, to mitigate this issue the Town engaged Allnorth to design and oversee construction of a new chlorine booster station on Magee Road.
Allnorth completed the preliminary engineering and full design of the project, however the Town decided prior to tendering that they would change disinfection methods at the water treatment plant (WTP) to gauge any difference in residual levels. To aid in this, Allnorth completed a WaterCAD analysis to convert the existing WTP to ammonia disinfection.
In addition to low chlorine residuals, the Town also had an issue of high disinfection by-products (HAAs and THMs) in their water. During the initial design, Allnorth suggested that the chlorine booster station would help boost residuals, however it could also increase disinfection by-products. As such, Allnorth conducted a WaterCAD analysis to model the Gander water system to study how the residuals and by-products would react with the implementation of a new booster station. Though this study it was determined that switching the water treatment plant to chloramine disinfection instead of chlorine would be the more cost-effective route, as this would solve both problems in the distribution system.
The Town of Gander made this change in 2017 and have had positive residuals in all areas of town since, reducing the THMs and HAAs substantially.
RESPONSIBILITIES
- Civil/Municipal Design
- Structural design for chlorine booster building
- Equipment location placement
- Project management
- Tender services
- Contract administration
- WaterCAD modeling
LOCATION
Gander, NL
