What are micropollutants?

The European Environment Agency defines micropollutants as substances that exist in very small traces in water, at micrograms to nanograms per litre. These anthropogenic organic or mineral substances come from a wide range of sources such as pharmaceuticals, cosmetics, personal care products, industrial chemicals, pesticides, detergents and household chemicals among others. However, there are differences in classification at the country or institutional level, particularly in regard to the inclusion of heavy metals.

The issue of micropollutants is not new – some substances have been on the European Union’s (EU) regulatory agenda for the past 50 years – however, they represent a mounting challenge for water operators. Globally, micropollutants can be found in increasing volumes in water and wastewater, and sources like the Water Quality Association estimate that up to 90% of oral drugs pass through the human body and end up in the water supply.

Across Europe under the EU Water Framework Directive, the Directive on Environmental Quality Standards lists 45 Priority Substances (and a further 15 on the watch list) with specific deadlines for their reduction and/or removal at wastewater treatment plants (WWTPs) and industrial outfalls. New substances are continually added to the list with new associated deadlines for compliance, e.g. perfluorooctane sulfonic acid (PFOS) in 2027, creating a complex and evolving landscape.

Geopolitical landscape

Tackling the issue of micropollutants has been driven by growing public concern and political will in anticipation of regulatory development. Europe is at the forefront of efforts to accelerate regulatory action to address the issue, however, to date enactment at country-level is mixed.

A number of countries in Europe led by Germany and Switzerland are engaged in addressing the micropollutants problem. Germany and Switzerland are already implementing full-scale facilities for micropollutant removal. Switzerland is undertaking mandatory upgrades to its largest 100 WWTPs by 2035. In Germany, despite a lack of national regulation, WWTP upgrades to ‘fourth stage’ polishing treatment are becoming more widespread following initial adoption in its more industrialised federal states. Other countries such as the Netherlands, Sweden and Denmark are following suit, and France is also responding to the environmental concern.

Countries like the UK are further behind in their journey. In early 2020, the UK set up a taskforce led by British Water to examine supply chain initiatives for wastewater treatment solutions, in the face of potential action in subsequent Asset Management Periods (AMPs). Spain and Belgium have historically faced a number of infringement procedures due to failures in compliance. A similar situation exists in Eastern Europe where most countries – for example Poland, Slovenia and Czech Republic, as well as aspiring EU members – have a long way to go before achieving the advanced treatment needs for micropollutants. That said, we are seeing investment taking place in many of these countries now. Thus, significant opportunities exist for EPCs and financing across Europe both in the short-term for the proactive countries, and in the medium term in countries which are falling behind the curve.

Technology portfolio

There is no ‘one size fits all’ approach for removing micropollutants from water and wastewater streams – different micropollutants require different removal technologies. This technology portfolio includes activated carbon (heavily relied upon by Germany and Switzerland), ozonation (preferred in France), ion exchange (IX) and membrane treatment such as nanofiltration (NF) or reverse osmosis (RO), ultraviolet (UV) (which is often thought of in terms of disinfecting but in fact has the ability to kill a wide range of substances), and advanced oxidation processes (AOP) (as trialed in the UK).

Cost and energy use are two further considerations in selecting technologies, which, when taken together with effectiveness, leave much room for improvement for technology providers. The question is: who will have the best technology to remove a broad spectrum of micropollutants for municipal treatment, not only specific substances? Municipalities must deal with a multitude of substances that originate from a variety of sources, whereas industries have to deal with specific micropollutants.

Next steps

The threat of micropollutants is only gathering pace especially in Europe where increasing concentrations are expected alongside an ageing population more reliant on pharmaceuticals, and where strong political support towards enforcing environmental regulations exists. Ultimately, we are still in a market that anticipates stricter regulatory changes and can expect this trend of facility upgrade to apply universally across WWTPs as polishing becomes Best Practice.