Metrolinx Finch West Light Rail Transit Project Incorporates NZW Rainwater Harvesting System

January 6, 2021

Finch West Light Rail Transit (LRT) Maintenance and Storage Facility (MSF) is a component of the overall Finch West LRT project by Metrolinx.  The new MSF will offer storage for the light rail vehicles (LRVs), as well as minor repair and maintenance service which will provide support functions for the Finch West LRT. In Metrolinx pursuit of sustainability goals, Finch West MSF is being designed and constructed to meet LEED (Leadership in Energy & Environmental Design) Silver Certification with a green roof.  One of the sustainability features in this facility is an on-site rainwater harvesting system that will collect rainwater from the building’s roof area, and treat it for non-potable reuse applications. The rainwater harvesting system will help to satisfy LEED, Toronto Green Standard, and provincial and municipal stormwater management requirements by saving potable water and minimizing stormwater runoff.

As the successful manufacturer selected for this project, Net Zero Water designed and built a turn-key rainwater harvesting system to collect rainwater and treat it to non-potable standards for toilet and urinal flushing applications. The design was customized to meet the project’s specific goals and objects. Key elements of the design include high quality treated water, durable and sustainable materials that will stand the test of time, and operational flexibility including full automation and controls.

The proposed rainwater harvesting system was designed to capture the 5mm storm and treat it to meet the anticipated water demand for toilet and urinal flushing from the facility. Due to presence of the green roof on this development, the rainwater treatment system was designed for Tier 2 disinfection to treat cistern water under the influence of green roof to clear and safe water. The proposed non-potable booster pump package will deliver 120gpm at 121 feet TDH at skid discharge.

The final packaged rainwater treatment solution consisted of a cistern with accessories, a treatment and non-potable booster package skid (built and tested with ESA certification), and a day tank with accessories. The skid was completed with a central control unit programmed to continuously monitor water levels in cistern and day tank, and equipment statuses and alarms on an HMI display with communication to the building automation system.

The Net Zero Water system is designed to be compact, configured for ease of maintenance, skid-mounted and complete with stainless steel pipe and fittings. As part of all Net Zero Water’s turn-key solutions, system commissioning, testing and training is included in the purchase of the system to ensure system operation and reliability for years to come.

The system start-up is scheduled for Spring 2021.