Practical sustainability in water treatment

Sustainability is an important and powerful guiding principle, but why is it always not the biggest priority? In this article, we cover some of the necessary considerations which are rarely talked about, but are equally important for infrastructure design and public health.

Reduce energy.
Minimise chemicals.
Lower carbon footprint.
Reuse water whenever possible.

We agree with these important goals, which are necessary – but in water and wastewater treatment, the most fundamental responsibility is protecting public health, and sustainability does not always align neatly. Every water treatment system sits at the intersection of risk, reliability, cost and environmental impact. Sometimes, optimising one factor often means making compromises elsewhere.

In this article, we list some trade-offs which decision makers consider, which explains why the water or wastewater treatment system has been designed and developed the way it was, or perhaps one of the many reasons why new promising water technologies are often overlooked in favour of trusted traditional systems.

Reducing chemicals vs. controlling pathogens

One of the most common sustainability targets is the reduction of chemical usage. From an environmental and operational cost perspective, this makes sense due to lower chemical transport and handling, reduced by-products and lower operating costs.

However, chemicals such as disinfectants play a critical role in preventing algae or microbial regrowth, controlling biofilms in pipe and tanks, and dosages vary as water quality varies. Lowering chemical use too aggressively introduces additional risk.

Energy efficiency vs. robust treatment

Energy consumption is a major focus for water treatment and sustainability reporting. Some energy-saving measures can significantly reduce operating costs and emissions, but they may also narrow the system’s buffer against shock loads, variable industrial water contaminants, and seasonal fluctuations.

Without buffer, recovery of the system can be slow, impacting operation and maintenance procedures.

Water reuse vs. public trust

Water reuse is often considered a sustainability win, but even when risks are managed, public perception plays a decisive role. Concerns remain around specific contaminants and active ingredients which may not be monitored in the laboratory, but may contribute to long-term exposure risks. Public engagement is essential to ensure treated wastewater is accepted as a water source.

Nature-based solutions vs. predictability

Nature-based treatment systems such as wetlands offer clear sustainability advantages but these systems can be sensitive to seasonal changes and may not be capable to manage extreme weather events. Such unpredictability translates into risk that impacts water quality compliance. In many cases, such systems are dependent on additional water treatment capacity planned further downstream.

Making trade-offs quietly

Engineers, utilities and plant owners regularly face choices such as:

• Adding another treatment step for safety, hence accepting higher energy use.
• Designing conservatively and optimising footprint, hence accepting a lower buffer for source water variations.
• Prioritise resilience, or meet efficiency targets.
• Dependency on algorithms and automation, or human operators.

Eventually, public health failures are immediate and visible, while sustainability shortcomings are cumulative and less obvious. Do you think this imbalance influences decision making?

Practical sustainability

True sustainability in water treatment is not about achieving the lowest possible numbers on paper. It is about balancing environmental goals with reliability, safety and affordability over the system’s entire lifecycle.

This is where a practical, engineering-led approach becomes essential. In many cases, simpler, well-designed systems deliver better outcomes – economically, environmentally and operationally.

The most sustainable water systems may not always look the most impressive on paper – but they are the ones that quietly protect communities, industries and the environment.