The Portland State University Maseeh College of Engineering building is LEED certified and uses a rain harvesting to collect gray water for use in toilets and labs.
Photo by Contech Stormwater Solutions
Click here to enlarge imageRain harvesting gathers stormwater from 13,000 square feet, about 25 percent of the engineering building’s roof. The rest of the runoff goes into three Stormwater Management StormFilter® systems from Contech Stormwater Solutions for processing by a compost media that filters soluble metals, oil and grease, total suspended solids, nutrients and neutralizes acid rain before it goes into the groundwater. Visible in the second-floor hydrology laboratory, the filtering stage of the treatment system also features a StormFilter. Contech donated the filter and engineering time to the school to support to sustainable practices, preservation, education, and ecological protection.
The smallest filtering system designed by Contech so far, it uses a single StormFilter cartridge held in a clear, plexiglass tank plainly visible to students working in the engineering lab. Placing it out in the open not only allows students, but also visitors to see the uniquely designed filtration system in action, normally impossible because filtration systems are found typically in underground concrete vaults.
The lab’s StormFilter also uses compost media that treats the roof runoff by removing pollutants before they can enter the graywater system. The runoff treated by the StormFilter is stored in a large water storage tank. After ultraviolet disinfection, the graywater is routed through copper piping to a pressurized storage tank on the first floor. From there it’s available for use in the bathrooms and hydraulics laboratory after chlorination.
Author’s Note:
Corky Lambert is a stormwater consultant at CONTECH Stormwater Solutions in Portland, Oregon, USA, with nine years of experience in the stormwater treatment field.