A Review of Water Reuse and Recycling, with Reference to Canadian Practice and Potential: 1. Incentives and Implementation

Abstract

As a country on the whole, Canada enjoys abundant freshwater resources, yet there remain regions with severe discrepancies between supply and demand. One solution to insufficient water supplies that has been gaining in popularity in other areas of the world is that of water reuse. Reuse or recycling of treated wastewater reduces effluent discharges into receiving waters and offers a reliable alternative supply of water for applications that do not require high-quality water, freeing up limited potable water resources. As compared to other countries worldwide, water reuse is currently practised infrequently in Canada. Use of reclaimed water requires a clear definition of the quality of water required, and while water quality criteria typically focus on pathogen risk to human health, chemical contaminants may also limit suitability for some reuse applications. Both health and environmental risk assessments are important steps in designing criteria for reuse projects. Alberta and British Columbia have recently produced guidance documents for water reuse projects; the permitted applications are discussed and the water quality criteria are compared with other standards and guidelines. Various treatment technologies for on-site and central wastewater reclamation facilities are described. Additional considerations for implementation of water reuse projects include project feasibility and planning, infrastructure needs, economics, and public acceptance.

Decision support for water policy: a review of economic concepts and tools

“…Water recycling becomes economically efficient for any of the following reasons: new water capacity becomes more expensive, the price of recycling falls, recycling economic efficiency rises, and environmental costs of new freshwater sources are higher. To more reliably identify these thresholds, further work is needed in identification and measurement of non-market benefits and costs, especially environmental damage reduced by avoiding new tapped freshwater sources (Exall et al, 2004).…”

Hydrodynamic Treatment of Wastewater Effluent Flocs for Improved Disinfection

“…Furthermore, the fecal eoliform count aehieved after only one pass of treatment (2.0 ± 0.7 CFU.mL) at a dose of 58 mj/em^ may be sufficient to meet British Columbia's standard for unrestricted water reuse (< 2.2 CFU/lOOmL) For unrestricted water reuse, California requires a geometric mean of less than 2.2 total eoliform per lOOmL (Exall et al, 2004). Hydrodynamic treatment coupled with ultraviolet disinfection has the potential to be a relatively simple and environmentally benign strategy for reducing pathogen discharge either into sensitive receiving waters or into final treated effluents intended for re-use.…”

Development and application of Total Coliform load duration curve for the Geum River, Korea

“…Pathogens associated with waterborne diseases include enteric viruses derived from human fecal contamination, bacterial pathogens, represented by Escherichia coli O157:H7, and the protozoan pathogens Cryptosporidium and Giardia . Potential pathogen point sources are waste water treatment plants (Exall et al, 2004;Lipp et al, 2001), combined sewer overflows, separated sewer overflows (Charles et al, 2003), slaughterhouses, and animal feedlots (Gessel et al, 2004). Potential non-point sources include illicit sewage connections, wildlife, septic systems, livestock, landfills, and pastures, as well as land application of manure or sludge (McMurry et al, 1998).…”