Water Initiatives: Toronto Water sets an example

Toronto Water sets an example

Toronto Water is responsible for water supply, wastewater collection and treatment, and stormwater management across the city. It caters to the water requirements of 3.6 million residents and businesses in Toronto and parts of the York and Peel regions. The utility manages one of the largest water and wastewater treatment systems in North America, providing services 24 hours a day, seven days a week.

The city’s water distribution network comprises four water filtration plants, four wastewater treatment plants, 18 water pumping stations, 67 wastewater pumping stations, eight combined pumping stations, 12 stormwater pumping stations as well as a variety of reservoirs and detention tanks. Besides, it operates and maintains about 5,551 km of distribution water mains, 550 km of transmission water mains, 3,730 km of sanitary sewers, 1,411 km of combined sewers and 4,981 km of stormwater sewers.

Water management initiatives

Toronto Water regularly assesses the condition of the city’s large and ageing network of underground pipelines, the majority of which are over 50 years old and some are over 80 years old. It predicts their life cycle and makes decisions regarding their refurbishment or replacement. The utility maintains inventories of its assets, ensuring adequate capacity; plans for future growth; prepares the annual capital programme for infrastructure repairs, replacement and rehabilitation; and conserves water resources through new policies, programmes, technologies and environmental assessments. The following are some of the key water management initiatives taken by Toronto Water…

Water mains replacement and maintenance: Every year, the city replaces approximately 3,000 sub-standard water service pipes during planned capital construction projects, such as road, sewer and water main works. Pipes require replacement if they are leaking or broken, smaller than the standard sizes, servicing more than one home (also called double-service), or are made of lead or galvanised steel. To address all these issues, Toronto Water undertakes an annual programme of water mains rehabilitation. The various measures deployed to protect water mains include:

  • Cathodic protection: One of the most popular preventive measures taken by the agency is the cathodic protection of water mains. Under this technique, the water mains are connected to a piece of another easily corroded metal, which acts as an anode of the electrochemical cell. Cathodic protection of metallic water mains is an effective method for reducing the breakage frequency and extending the useful life of pipes. It is generally applied to cast iron and ductile iron pipes.
  • Cleaning and cement mortar lining: This method is used to counteract a number of problems in cement mortar lining. The chemical nature of the cement maintains a zone of alkalinity at the mortar/metal interface, thereby preventing corrosion of the pipe wall. Cement mortar also has the ability to self heal and seal cracks.
  • Structural lining: This is a trenchless technology, which helps improve water quality, stop water loss/leakage, structurally renew existing pipelines, improve the hydraulic characteristics of pipelines and extend their service life, among others. Canada has become a world leader in trenchless water mains renewal using structural lining. Every year, more than 200 km of water mains are lined in Canada.
  • Water main flushing: Another important technology deployed by the agency is water main unidirectional flushing. Water main flushing is the process used to clean water mains. Water system valves are turned off to isolate a section of the water mains. Water is then flushed in one direction at a high speed to produce a scouring action that removes the built-up sediment. The process is deployed by the utility to improve water quality and maintenance.

Closed-circuit television (CCTV) maintenance of municipal sewers: The agency has installed CCTVs for managing sewer service connections and inspecting municipal sanitary, stormwater and combined sewer systems. It provides digital information that helps in determining the maintenance and rehabilitation needs.

Sewage flow monitoring: Toronto Water monitors the sewerage system by identifying and removing sources of infiltration, stormwater and physical restrictions that affect the flow in sewers. Wastewater is collected and treated 24 hours a day, seven days a week through 3,730 km of sanitary, 1,411 km of combined and 401 km of trunk sewers; 507,548 sewer service connections; 87 wastewater pumping stations; and four wastewater treatment plants. As part of the exercise, the agency identifies sources of stormwater entering the sanitary sewer system that lead to basement flooding. It inserts a harmless dye product into downspouts, catch basins or area drains. The path of the discharged dye is traced to ascertain the condition of the components of a sewerage system. It also helps in identifying the sources of leakage in the system.

Mandatory downspout disconnection programme: In order to enhance the city’s drainage systems, the agency introduced the mandatory downspout disconnection programme into the basement flooding protection programme. The aim was to slow down the flow and reduce the volume of runoff reaching storm sewers during a rain event. During heavy rain, the sewers can become overloaded, which can increase the risk of basement flooding and release of polluted rainwater into local waterways. By disconnecting downspouts and directing stormwater into the property, it can minimise the risk of sewer overloads. This by-law is applicable to all buildings, including industrial, institutional and commercial ones.

Automated water meters: Toronto Water implemented a mandatory water meter programme in 2010 to streamline the billing process and improve revenue collection. The scope of work involved replacement or installation of new automated meters in every home and business in the city to provide an equitable system for all Toronto Water customers. As a result, customers only pay for the water they actually use.

Water efficiency plan: The city’s water efficiency plan, approved by the City Council in 2003, is aimed at creating in-system capacity by reducing water consumption across the city to service the population and create employment. By reducing water consumption, with the implementation of efficient fixtures and other measures, the plan provided a way of creating capacity within the existing system to avoid costly infrastructure expansions. In addition, it provided environmental benefits with the reduction in energy usage for pumping, carbon dioxide emissions, chemical usage at water and wastewater treatment facilities, and effluent discharges from wastewater plants. The key initiatives taken to minimise energy costs include:

  • Demand-side management (peak shaving and global adjustment curtailment)
  • Release of grants and incentives to implement energy efficient upgrades
  • Reduction in energy purchases through on-site generation
  • Operations optimisation

The way forward

Going forward, Toronto Water plans to continue with its smart initiatives to achieve higher performance levels and improve service delivery. The agency has approved a capital plan worth $12.72 billion for a 10-year period from 2018 to 2027. The key issues that have been taken into consideration in the capital plan include ageing infrastructure, stormwater management and resilience, long-term financial sustainability and growth planning.

The 2018-27 recommended capital budget of $865.22 million for Toronto Water (excluding the carry-forward funding) will include projects such as water mains replacement and rehabilitation ($134.68 million), sewer system replacement and rehabilitation ($83.55 million), trunk sewer and pumping stations ($46.339 million), basement flooding protection ($43.08 million), wet weather flow master plan ($42.043 million) and erosion control ($2.83 million). All these projects are expected to further strengthen the water supply and sewerage system in the city. That said, the success of these projects would require timely implementation, greater community participation and increased private sector involvement, and technology penetration.