Potable water treatment and reuse of domestic wastewater in the CMHC Toronto 'healthy house': Fid-Bau Portal

Potable water treatment and reuse of domestic wastewater in the CMHC Toronto 'healthy house'

Townshend, A.R. / Jowett, E.C. / LeCraw, R.A. / Waller, D.H. / Paloheimo, R. / Ives, C. / Russell, P. / Liefhebber, M.

In order to demonstrate 'unplugged' housing, two adjoining three-bedroom houses were built in downtown Toronto on very small lots which have no sewer or water services. Electricity is supplied by photovoltaic generators with battery storage in one house and two-way grid supply in the other. A design 120 L/day rainwater supply is collected in cisterns, buffered with limestone gravel, and passed through a multi-media gravel, sand, and activated carbon filter. After ultraviolet disinfection the water is distributed on demand for potable and other uses (actual use approx. 265 L/d). Wastewater is treated by a septic tank with effluent filter below the carport, a recirculating tank below the basement, and a Waterloo Biofilter housed in a sealed stainless steel enclosure in the basement and ventilated by forced air vented through the heat recovery unit. A 120 L/day portion is disposed of on-site in a leaching bed, and the design 600 L/day remainder is further treated for reuse in the house (actual approx. 325 L/d, total 590 L/d). For reuse, the wastewater is polished with two multimedia filters and ozone disinfection. Reclaimed water is presently for the non-potable uses of toilets, laundry, gardening, but potentially baths and showers. The system is working well at the single-house scale it was designed for and will find application where water supply is expensive or scarce, and where tight soils and small lots make disposal of a standard household flows difficult.