We can start by considering water sources that are available locally, through reuse of rainfall, stormwater runoff and wastewater produced. These sources employ flexible, autonomous infrastructure that travels shorter distances and has the potential to reduce the overall environmental footprint. It can accomplish this by lowering consumption of materials, energy, and chemicals, saving on build costs, and reducing opportunities for leakage and losses. More specifically, the following four groups of distributed technologies can be applied to supplement existing centralized water infrastructure in achieving a balanced, circular metabolic approach:
- Water supply and water demand management. Educate users on water conservation, introduce rebate programs, or introduce water restrictions during times of drought.
- Low-Impact Development (LID) and Green Infrastructure (GI). LID and GI tend to mimic the natural water cycle and thus reduce stormwater runoff volumes, while increasing infiltration into the ground. At the same time, LID and GI have the potential to naturally capture and reduce CO2. This is achieved with green roofs, rain gardens, permeable pavements, bioretention facilities, or vegetated rooftops.
- Green buildings. Use high-performing fixtures (such as low-flow toilets, building wastewater recycling, wastewater reuse and rainwater harvesting) to reduce the demand and waste production.
- Greywater management and onsite wastewater reuse technologies. On-site processing of wastewater can convert organic solids into carbon-rich soil that can be used to support crops, gardens and green spaces. The water that remains can be recycled for non-potable applications, such as toilet flushing, irrigation, and cooling towers.
Implementation While these technologies have been implemented in isolation across Canada, a mindful and integrated approach to urban planning needs to become the norm in order to protect and use our resources most efficiently. Transitioning fully to the circular metabolic approach in the water sector using decentralized technologies is essential to meet growing urban needs and will require major changes in the way we plan, design and fund our infrastructure7. These changes will require collaborative leadership from industry, academia and government8. We must problem-solve complex urban water issues in creative and sophisticated ways, and work to embed future ready urban water systems across Canada and beyond.