Water reclamation – The Global Case
Water reclamation is gaining traction globally as its benefits are many: providing an additional water source (deferring the need for alternate freshwater supplies), lessening the impacts of droughts, acting as an environmentally friendly option for treatment and disposal of wastewater, and reducing the discharge of excess nutrients in treated effluent to surface waters.
Reclaimed water is used in both non-potable and potable applications. Non-potable usage has been well accepted globally by communities, practitioners, and regulators. For example, the semiconductor industry has water reclamation and direct non-potable reuse at the centre of their progressive water management strategy.
On the other hand, direct potable reuse is still a tricky issue, with considerable psychological barriers. The most famous example of direct potable use is from Windhoek, Namibia. Using multi-treatment steps, the Goreangab Reclamation Plant produces 21 million litres per day of drinking water. The plant has been operating since 1968.
Indirect potable reuse has emerged as a successful alternative. In Orange County, California, 492 million litres per day of reclaimed water is used for a Groundwater Replenishment System. This is sufficient to meet the water requirements for over 850,000 residents. In Singapore, high-grade reclaimed water (NEWater) is used for both indirect potable and direct non-potable purposes. The City State plans to meet 55% of its 2060 water demand (approximately 1600 million litres per day) from NEWater.
Situation in Canada
Although Canada has approximately 20% of the world’s fresh water, parts of the country are experiencing continued drought. Local governments have stopped issuing new water licenses in certain watersheds due to over allocation. Notwithstanding, industries such as the newly minted Hydrogen Hub in the Alberta Heartland and planned canola plants and potash mines in/near Regina will require huge amounts of water.
Such demands will continue to exacerbate the water supply issue. More regions of the country will look for resilient water supplies. Water reclamation can potentially fit the bill in certain scenarios. Associated Engineering has been helping clients with water reclamation projects for decades, such as EPCOR’s Gold Bar Wastewater Treatment Plant Water Reuse Project in Edmonton.
Local Context is Everything
We have learned a few things along the way. Some are in the details: nuances in turf grasses and underlying soils can markedly influence the technical approach, and even feasibility, in displacing traditional water sources with reclaimed water in turf irrigation situations, as can equipment metallurgy in industrial reuse applications such as cooling towers.
Others are more broad-based; the subject is complex and requires a holistic, multiple bottom line + risk evaluation approach to ensure a robust comparison of reclaimed water to a traditional water source. Knowledge of project-specific opportunities and constraints, and knowing which questions to ask, goes a long way to ensuring a successful project outcome.
about the authors
Soubhagya Pattanayak, Ph.D., PMP is Discipline Lead, Wastewater/Resource Recovery in Calgary. He spent 10 years living in Singapore and working on industrial water reclamation and reuse and other membrane-based wastewater treatment and desalination projects in the Asia Pacific Region.
Dean Shiskowski, Ph.D., P.Eng. is Associated’s Vice President, Water Resource Recovery. His broad water reclamation and reuse experience spans large planning studies conducted under Alberta’s Water Management Framework to technology demonstration projects for municipal and industrial clients.