UBC Undergraduate Research

An investigation into filtration of the cistern-collected rainwater for the new UBC Student Union Building Yeung, Peter; Chu, Teresa; Khoo, Andy; Chang, Jerry


The new Student Union Building, to be completed in 2014, at the Vancouver campus of University of British Columbia will collect rainwater through the rooftop for non-potable use in the building. A study is conducted to investigate on a possible water treatment process after the rainwater has been collected. The proposed design includes filtration, disinfection, and overflow and back-flow preventions. In the water treatment system, the collected rainwater first runs through a filter to remove the large pathogens. The biosand filter is used to filter the water and is capable of eliminating greater than 90% of the coliforms. The biosand filter is chosen primarily due to its low impact on the environment, zero energy consumption during operation, and inexpensive costs. Then, the rainwater is disinfected by ultraviolet light to ensure all bacteria are removed. The system also contains sensor and control valves in the case of water overflow or backflow. Both the biosand filter and the ultraviolet disinfection methods have low impact on the environment and present no significant harm to humans during operation. The cost of biosand filter is extremely low to purchase, to maintain and to operate. Although the ultraviolet system is more expensive, it operates at low cost and will balance the cost after a period of usage. The proposed system is recommended based on the investigation performed, as each component has been evaluated to be affordable and sustainable. Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”

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