Total tonnage of residential waste has not declined, but tonnes going to landfill has
Most residential waste is collected at curbside by the City. Total residential waste collected in Ottawa has remained relatively steady since 2005. This means there has been some decline in per capita waste generation. But consistent levels of “throughput” suggest that overall consumption levels, and all the associated “upstream” impacts, have not significantly diminished.
There has, however, been a significant decline in the amount of waste going to landfill (i.e., garbage). In 2010, the year the Green Bin program was introduced, garbage declined by 12% compared to the previous year. In 2013, the first full year of bi-weekly garbage collection, it declined by another 18% compared to 2011.
Waste from the private and institutional sectors accounts for well over half the total waste going to landfill, but is not a municipal responsibility.
Participation of Ottawa households in composting compares favourably to other major cities
Based on Statistics Canada’s Households and the Environment Survey in 2011, 85% of Ottawa residents participated in the composting of yard waste and 63% in composting kitchen waste, either via curbside collection or on their own properties. This is a relatively high participation rate among major Canadian cities.
The proportion of Ottawa households separating compost for collection at curbside rose from 48% in 2007 to 69% in 2011, partly reflecting the introduction of the Green Bin program in 2010. Prior to this, curbside collection was offered only for yard waste.
Notwithstanding this level of participation in curbside composting programs, much of the material still going to landfill could be diverted through green bins.
Household consumption of water has declined continuously and significantly since 2007
The residential sector, compared to the industrial, commercial and institutional sectors, is a much larger consumer of municipally-supplied water in Ottawa. That said, between 2007 and 2015, per capita use of water by Ottawa residents dropped by over 20%. Based on 2009 data, of Canada’s six major cities, only Edmonton had a lower rate of residential consumption.
Water metering and pricing have been cited as reasons for declining residential water consumption across Canada. Ottawa’s advanced meter infrastructure program began in mid-2011. Although the rate structure did not change at this time, the resulting public profile may have made residents more aware that they pay per volume for water use. Adoption of efficient fixtures such as low flush toilets and low flow shower heads has also been promoted and in some instances financially supported by the City for over a decade.
Declining consumption has resulted in a significant drop in volumes of water processed at Ottawa’s two treatment facilities – an average of 275.3 megalitres per day in 2013, compared to 369 in 2001. Ottawa’s drinking water comes primarily from the Ottawa River, so the source is not limited. However, water treatment and distribution, and wastewater treatment, are energy intensive processes. So a key environmental benefit of decreased water consumption is reduced energy use and associated GHG emissions.
- City of Ottawa. Environmental Services Department. 2015
- City of Ottawa. Water Meters. Accessed June 12, 2016.
- City of Ottawa. Water Efficiency Strategy. Accessed June 12, 2016.
- City of Ottawa. Water, Wastewater and Stormwater Rate Structure Review. Accessed June 12, 2016.
- Environment and Climate Change Canada. Municipal Water Use Data. Accessed June 15, 2016.
- Ottawa Open Data. Drinking Water Summary Data. Accessed June 12, 2016.
The proportion of households using tap versus bottled water has been increasing
In 2015, 81% of Ottawa households used tap water for drinking, compared to 76% in 2013. Over this period, five of Canada’s six major cities saw at least some shift to use of tap water for drinking, with Edmonton showing by far the most dramatic shift, followed by Calgary.
Growth in the use of tap water for drinking is good news environmentally, since the energy and resources associated with producing and filling bottles, and shipping them often huge distances, far exceeds that used by public utilities to process local sources for tap water.
At the same time, however, the sale of bottled water in Canada continues to grow modestly but steadily, with an estimated 2.5 billion litres sold at a retail value of $2.4 billion in 2015.
- Euromonitor International. Bottled Water in Canada. 2016. Accessed June 12, 2016.
- Statistics Canada. CANSIM Table 153-0063
Discharges of untreated sewage to the Ottawa and Rideau Rivers have dropped significantly
Combined sewers are those that collect surface runoff as well as sewage. They are common in older residential neighbourhoods in Ottawa. In heavy rain or snowmelt, the capacity of these pipes is not always adequate to carry the volume to the wastewater treatment plant. As a result, untreated sewage is discharged directly into the Ottawa and Rideau Rivers along with rainwater.
Since 2009, through the City’s Ottawa River Action Plan, a range of measures have been implemented to address this problem. Both the number and volume of CSO releases have declined. A key measure has been Real Time Controls to remotely monitor and activate overflow equipment. The replacement of some combined sewers with separate wastewater and stormwater systems has also been ongoing over a number of decades, and separation has taken place in well over half of Ottawa’s original combined sewer area. Two large capacity storage tunnel capable of holding 43,000 m3 of sewer overflow are planned.
These engineering solutions have clearly delivered important improvements, although at very substantial cost. Projected cost for the tunnels alone now stands at over $230 million. Some cities are investing significantly in green infrastructure approaches (e.g., landscape features that mimic natural mechanisms for storage and infiltration) as a cost effective way to address combined sewer overflows and climate risks. Ottawa has so far taken only very modest steps towards implementing such approaches.
- Bolivar - Phillips. Adaptive Approaches in Stormwater Management. Prepared for the City of Ottawa. July 2013.
- City of Ottawa. Combined Sewer Overflows. 2015.
- City of Ottawa. Combined Sewer Storage Tunnel. Accessed June 12, 2016.
- City of Ottawa. Projects and Status Updates. Accessed June 12, 2016.
- Ottawa City Council Minutes. June 10 2015. Accessed June 12, 2016.