November 27, 2017
Net Zero Water worked diligently with both the developer and engineer on the Islington Terrace project in Toronto. By designing a highly efficient low impact development (LID) solution, our packaged system with full automation was presented to our client. Net Zero Water was specified for this rainwater harvesting and cooling tower makeup application.
Net Zero Water’s Toronto client was required to provide a water balance plan for their site. The solution was to retain stormwater from running off their site and use it through infiltration, evapotranspiration and/or rainwater reuse. This particular property features several green roofs due to their ability to absorb rainwater and release it slowly over a period of several hours. It’s been shown that water released by green roof systems can reduce site runoff by 50% or more. The runoff from the green roof and other roof surfaces will then be harvested for reuse.
Some of the challenges included water quality collected as green roofs can impart constituents such as phosphorus, tannins and possibly excessive microorganisms. These constituents can be difficult to remove. Net Zero Water designed a system which would efficiently treat rainwater runoff from the green roofs using no liquid chemicals or large volumes of potable water for back-washable filters. Treatment included ozone for full oxidation of organics, followed by a bag filter to catch all dissolved particles, with the final step being UV disinfection in order to remove all microbial contamination.
Installation scheduled for 2018.