What should you prioritise when planning for water security and reuse?

All countries and regions have their own regulatory landscapes. In some places there are centralised nationwide policies, while in others there are provincial, state and even municipal regulations that mandate how water resources must be managed. Understanding local regulations is the first step to determine the technology and strategy for water security and reuse.
 
In the United States (US), regulations are state driven, with California leading in both indirect and direct potable reuse standards. Projects must meet stringent pathogen and chemical removal requirements, with multi-barrier validation and operator certification.

In Australia, there is emphasis on triple-barrier approaches and robust research partnerships, primarily with universities, to address emerging contaminants. Regulatory frameworks are evolving, with a focus on both centralised and decentralised solutions.

Both Europe and Asia focus on different approaches. In Europe centralised and decentralised reuse is advancing, with a strong focus on environmental protection and public health. In contrast, Asian nation Singapore stands out for being a world leader in indirect potable reuse, driven by land constraints and necessity, with rigorous regulatory oversight. As for the Middle East, there is rapid adoption of advanced and emerging technologies, with regulatory frameworks adapting to support innovation and water security goals.

It’s essential to align with regional regulatory requirements and contribute to evolving best practices through collaboration and data sharing. Organisations must identify key technologies and implementation strategies, considering public outreach and stakeholder engagement programs as well as maintaining regulatory compliance.

There are four different types of technological options for water reuse, which are often coupled together,depending on the organisation’s operational needs, regulations, resources and other variables — such as desired community impact.

Membrane bioreactors combine biological treatment with membrane filtration, offering high removal rates for pathogens and contaminants. They are increasingly used as a pre-treatment step before advanced purification, especially in large-scale projects in the US and Australia.

Another alternative is advanced oxidation processes (AOP), such as UV with hydrogen peroxide, which are critical for breaking down trace organic contaminants and emerging pollutants. This system is often used after membrane filtration to confirm chemical safety and regulatory compliance.

Carbon-based treatments and multi-barrier approaches are also popular choices. Both granular activated carbon (GAC) and biological activated carbon are used for further removal of organic compounds and taste and odour control. These are especially valuable in direct potable reuse (DPR) schemes and in regions where brine disposal from reverse osmosis (RO) is challenging. The latter approach combines multiple treatment steps (e.g., ultrafiltration, RO, AOP, GAC) for robust pathogen and chemical control. This approach is standard in leading projects, such as Orange County’s Groundwater Replenishment System and Australia’s Western Corridor Recycled Water Project.

Getting the balance right between the technology and the implementation strategy is key. Variables such as design, control and monitoring are essential when considering which technologies match with local water sources, end use requirements and environmental buffers, such as groundwater aquifers or reservoirs, to determine the most suitable technology mix. It’s important to consider decentralised versus centralised systems — decentralised solutions may use simplified treatment trains tailored to smaller communities or industrial clusters.

For technology to deliver the desired result, implement real-time monitoring and controlling at key stages. This includes data collection on process reliability, enabling smarter decision making and rapid response to deviations.

Water’s vitality makes it a matter of public interest — everyone will want to know how you’re managing it, recovering it and what this means to them and their lives. Begin outreach early, before project launch; agencies with established reputations and ongoing community engagement are more likely to succeed. Keeping the public informed through demonstration facilities and transparent communication about safety, benefits and the science behind potable reuse is essential for awareness and social license of the project.

Stay close to the public and stakeholders, using terminology that resonates with the local community. In the US and Australia, terms like “pure water” or “purified recycled water” resonate better with the public than “wastewater reuse.” Tailor language to local preferences. Engage regulators, elected officials and external experts early and often. Foster collaboration between utilities, government and the private sector to accelerate project delivery and acceptance.