More Purified Water
Thanks to technological innovation, wastewater treatment is evolving to successfully handle application of European regulations, which are increasingly stringent.
Tertiary treatment or regeneration of wastewater in wastewater treatment plants (WWTPs) is an additional process to purification, aimed at providing the treated water with quality so that it can be used for new purposes not related to human consumption. These purposes are typically industrial, street cleaning, irrigation of green areas, or even environmental uses, as its discharge with higher quality benefits the aquatic ecosystems that receive it. The use of regenerated water allows us to reserve higher-quality water for human consumption, contributing to the net increase of reservoir water availability.
A particularly interesting use for regenerated water from WWTPs is its return to watercourses and the recharge of aquifers. Aquifer recharge projects like LIFE Matrix have been developed. We discuss this in the post Groundwater. Invisible, Yet Essential. But there are also others, like DINA-MAR, to determine which zones in Spain can recharge with minimum impact standards and study related technological developments, or the LIFE ENSAT project, which developed an efficient technique to reduce some of the emerging compounds (we will discuss this later) in recharge water, thereby improving the quality of the aquifer’s water.
Industry also reuses water in its processes in auxiliary systems (like cooling circuits and boilers) to protect nozzles, sprayers, or cleaning equipment, wash industrial machinery, for cleaning systems, to wash tubs in the agri-food industry, and more. Depending on how it is used, different treatment techniques are employed to obtain the most suitable quality.
Under the umbrella of the European Green Deal, a package of political initiatives that aspires to a pollution-free environment by 2050 and considers that the cost of inaction is much higher than the cost of prevention, the Zero Pollution Action Plan sets the target by 2030 of improving water quality by reducing waste, discarded plastic in the sea (by 50%), and microplastics dumped in surface waters (by 30%).
New developments in European regulations, and by extension, in Spanish regulations, establish stricter requirements for nutrients coming from wastewater, new regulations for microcontaminants, and new control requirements for microplastics. These are emerging contaminants: compounds which, thanks to progress in analytical chemistry in recent years, can now be quantified in water at very low concentration levels. They can have harmful effects on both the environment and on human health. In fact, some emerging contaminants behave as endocrine disruptors, although they may have other toxic effects.
The number of substances that can be considered emergent is undetermined and includes pharmaceuticals, pesticides, and other biocides, additives used in materials such as antioxidants, flame retardants, plasticisers, anti-rust agents, household products like detergents, cosmetics, and creams, and drugs.
Every two years, the European Commission revises the observation list through which it identifies possible new contaminants that then go on the list of priority substances if they pose a significant risk, determined based on the danger and concentration of the substances in the water. In 2022, 25 substances with well-documented problematic effects on nature and human health were added. These include PFAS, a large group of persistent chemical substances used in cookware, clothing, furniture, firefighting foam, and personal care products, as well as certain pharmaceuticals such as pain relievers, anti-inflammatories, and antibiotics.
Wastewater purification treatments to control emergent contaminants apply advanced technologies like ozonisation, activated charcoal absorption, and membrane filtration. Given that 92% of toxic microcontaminants found in the EU’s wastewater come from pharmaceutical and cosmetic products, a new system for increased producer liability will force them to pay the expenses to eliminate them. The principle of “the polluter pays” is still entirely valid, both in terms of liability and to provide incentive to research and innovate with toxic-substance free products, in addition to finding funding for fairer wastewater treatment.
Having appropriate monitoring and purification technologies, as well as suitably distributing the cost for implementing them, are essential steps toward obtaining more and better-purified water.
