McCue was contracted to design, supply and operate a rental water treatment system to treat water from the rail receiving pit excavation for the G3 Grain Terminal Vancouver construction project in North Vancouver, BC. The rail receiving pit excavation intersected an area of environmental concern related to historical site operations. Water treatment was required to remove both existing contaminants and contaminants generated by construction activities including total suspended solids (TSS), pH, and heavy metals.
Operations at the site became challenging when construction in the pit excavation and saltwater intrusion from pumping elsewhere on site significantly altered the system inlet water profile; in some cases, the inlet contaminant concentrations were 1,000% higher than estimated. Although the design and treatment process were highly flexible, changes to the treatment process were required to meet the new water specification. In an effort to limit downtime, McCue added operators to the project and engineered a new treatment process, moved and reinstalled the system in a new location, moved and reinstalled a tank farm for treated water, and commissioned the modified system in a condensed, two-week timeframe. Once brought online, the system was capable of treating the water from the pit for discharge to Burrard Inlet via a storm water outfall under the jurisdiction of the Vancouver Fraser Port Authority (VFPA) and system operation was resumed.
McCue Engineering Contractors proves chemical precipitation has a greater range of water treatment capability than previously thought possible.
To support the Environmental Assessment (EA) of a new mine project in BC, McCue Engineering Contractors completed the preliminary design of a water treatment plant (WTP) using a water profile modeled for the future mine.
McCue created a synthetic water sample from field leachate samples and laboratory-grade salts to match the modeled inlet water profile. The sample was used to develop and validate a chemical water treatment process at a bench scale and provide effluent quality data for impact assessment modeling. Bench scale data also advanced the design of the WTP from preliminary to detailed.
McCue later validated the treatment process with a full scale WTP in Metro Vancouver, BC. Although strict standards for copper and zinc, seawater intrusion, and construction activities made the water treatment project technically challenging, McCue’s WTP removed heavy metals from contaminated groundwater to meet both Provincial and Federal Surface Water Quality standards for marine discharge.
This work contributes to the body of knowledge for precipitation of antimony, chromium and copper where previous literature indicated no or negligible removal. McCue’s work has provided valuable data on metals precipitation performance that could benefit EA work at mine sites globally.
