Water reuse: 3 examples showcasing circularity in action

As companies rethink business models to create more resilient and shorter supply chains, we should use this moment as an opportunity to rethink how we value water and the potential resources it offers.

The pandemic proved that the water industry, often undervalued and underappreciated, is vital to ensure clean water is flowing to enable sanitation and hygiene to contribute to stopping the virus’s spread.

However, just because we have done things a certain way, does not mean they cannot be improved, tweaked, reinvented or improved to offer a better solution to meet water quality and quantity challenges.

Promoting a circular/One Water approach

Historically, water has been treated, distributed via kilometres of pipelines, and recollected as wastewater to then be treated again before being disposed of into the environment.

This linear process is repeated time and time again. The natural environment acts as a buffer between treated wastewater being of disposed upstream and water later being collected for consumption downstream.

A circular approach, meanwhile, enables additional value to be generated along this journey. 

Instead of a single-use process of take, treat, use and dispose, water can be reused, as it can be repositioned as a vector of resources, including energy and materials.

A report published by the United Nations Educational, Scientific and Cultural Organization (UNESCO), entitled ‘Water reuse within a circular economy context’ said that reusing water provides “new approaches to meet the increasing urban demand”.

Potable water reuse has also been credited by the World Health Organisation (WHO) as a “realistic, practical and relatively climate independent source of drinking water”.

Despite the recognised advantages and positive benefits of water reuse, as part of a circular economy, still “not enough is being done”, according to Abou Amani, director of UNESCO division of water sciences.

Three global examples of water reuse

While the number of water reuse projects is growing, there are three noteworthy examples connecting California in the US, to Namibia and Singapore.

California's groundwater replenishment leadership

In California, the Orange County Water District (OCWD) was one of the first authorities to master water reuse with its flagship Groundwater Replenishment System (GWRS).

The three-stage advanced process cleans up wastewater before putting it back into the Orange County aquifer to create a sustainable water supply for future use.

Orange County built its first facility in 2008, which boasted a 265,000 cubic metres per day (m3/day) capacity. After two further expansions, the site will have almost doubled its capacity, providing enough water for about a million people.

OCWD has scooped several awards for this initiative, including the prestigious Lee Kuan Water Prize in Singapore, as well as the “Leading Utility of the World”.

While recently retired, the legendary Mike Markus was the general manager at OCWD. I had the pleasure of interviewing Mike a couple of years ago about his 30+ years helping to build one of the leading utilities of the world (video embedded below).

The GWRS project even inspired the Singapore water agency, PUB, to introduce its reuse solution, called NEWater.

The Singapore approach: NEWater

One of the “Four National Taps, " which also includes desalinated water, imported water, and water from the local catchment, NEWater has helped Singapore overcome a lack of natural water resources.

Today, five NEWater plants are supplying up to 40% of Singapore’s current water needs. By 2060, NEWater is expected to meet up to 55% of Singapore’s future water demand. It’s quite amazing to think that over half of the nation’s water will eventually come from its wastewater.

By branding reused water as NEWater and including it as part of its long-term water strategy, Singapore has also overcome one of the biggest challenges to implementing water reuse: public resistance.

Both the Californian and Singapore projects are examples of indirect potable reuse (IPR), meaning the treated water is sent to the environment, be it a reservoir or aquifer, before being retreated and consumed.

However, the final example is one of the oldest and perhaps best-known examples of direct potable reuse (DPR). 

Namibia: the cradle of water water reclamation

The city of Windhoek, Namibia, successfully implemented the Goreangab plant in 1968 and has proven over the last 50 years that “DPR can be more economical than indirect potable reuse as no environmental buffer is needed”, according to the IWA.

Referred to as the “cradle of water reclamation”, this site produces purified water for the city’s 400,000 residents.

The unique element here is that the water is not treated again at conventional water treatment plants. Instead, it goes directly to the distribution system, hence the name direct potable reuse.

Going one stage further, the nation is now moving ahead with a second development (as covered here on Aquatech Online - https://shorturl.at/vN017).

Germany private bank, KfW has agreed to finance the next DPR project. The Namibia Water Corporation, NamWater, will implement the project, which will increase the supply of drinking water from the reclaimed water plants in Windhoek to 50%.

More recently, in December 2023 the California State Water Resources Control board approved direct potable reuse regulations.

The future must be circular

For circular economy partnerships and projects to be sustainable in the long term, they need to be scaled.

As we build a more connected world, accelerated by digitalisation, the reset also enables us to evaluate value chains (from watershed/supply chain to consumers/customer) and the role of water, and water companies.

If we are to ensure a green recovery, then forging a circular economy will be a fundamental part of this.

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• Part of this article was originally written for Qatium under the headline: Why water reuse is key to a circular future: https://shorturl.at/bjow4