A review of water reuse and recycling, with reference to Canadian practice and potential: 2. Applications

Common water reuse applications include agricultural and landscape irrigation with treated municipal wastewater, industrial recirculation of process waters, rainwater collection, and groundwater recharge for non-potable and indirect potable reuse. As compared to other countries worldwide, water reuse is currently practised infrequently in Canada, with the focus of most of the water reuse effort within Canada on agricultural irrigation applications. Landscape irrigation and other non-potable urban uses are practised to some extent, but provide an opportunity for expanded application of reclaimed water. Similarly, while water recycling is practised to various degrees within specific industrial sectors, further industrial water reuse and recycling affords an opportunity to conserve large volumes of water. The Canada Mortgage and Housing Corporation (CMHC) has supported a great deal of research into treatment and reuse of domestic greywater for non-potable uses within individual buildings, as well as some work on rainwater collection and use. Groundwater recharge and potable reuse are practised to some extent in extremely dry regions of the world, but public health concerns with respect to emerging trace contaminants may limit the spread of these reuse applications. The main issues associated with each of the above applications are reviewed, and the state of Canadian water reuse and recycling is described.