MME399
FACULTY ADVISOR: DR BUCHAL AND DR BARGHI
EXECUTIVE SUMMARY
Harvesting of Rainwater for the Green Building
MARCH 2, 2005
By Kerry Fraser, Scott Martin, Gabe Traczuk, Andrew Watson
Usable water is becoming an increasingly valuable commodity throughout the world.
This is not often appreciated in North America, despite increasing water costs, and a project of this type can assist greatly in adding to the understanding of a growing worldwide problem. By developing a system to harvest and process rainwater and snow into a useable state, potable water resources can be conserved.
Team Apex evaluated water demand using the information provided in the Green
Building Proposal and, although the information is still tentative, a usable figure was obtained. Due to cost restraints, it was determined that creating potable water would be unfeasible for the purposes of this project. As such, water will be used for toilets, urinals and sinks.
The design consists of five drains covered with weirs - to prevent entrainment of large solid particles on an inward slanting roof, which drains into a 1000L sedimentation tank. Solid particles are precipitated in the tank and particles not dense enough to settle are filtered out by a 2 micron mesh around the perimeter at the top of the tank.
The clarified water is disinfected using UV radiation emitted by six low pressure mercury lamps. Finally, the disinfected water will be continuously aerated through a cascade fountain. A connection to the municipal water supply is maintained to ensure continuous flow. The water is then pumped to a tank on the third floor from which it is supplied to washrooms.
This system is not designed primarily as a cost saving measure, although it has been created to minimize startup and maintenance costs. It has been designed largely as an educational experience for occupants of the building and will be made visible by the aeration fountain in the atrium. Over 50000L of water can potentially be saved per month and a small savings of approximately $720 a year can be achieved.