Water reuse technologies, an ally in the battle against emerging contaminants (ECs)

Biological effects and the consequences of emerging contaminants (ECs) on ecosystems can be mitigated through water treatment.

How many substances do we discard in our rivers and seas every day through waste water? Many more than we think. Medicines, cosmetics, cleaning products, and so on. Until very recently, we did not have the technology precise enough to detect and measure the presence of emerging contaminants in water.

In terms of quantity, the presence of ECs seems negligible, in the order of one particle per billion or even trillion. But their persistence can lead to risks both for the health of people and the environment. Fortunately, innovative initiatives have now been launched to eliminate or reduce them to safe levels in the water cycle.

What will I learn from this article?

Increasingly more contaminants in water

It is estimated that 3.6 billion people worldwide live in areas of water scarcity for at least one month a year. According to United Nations World Water Development Reports, however, this figure could reach between 4.8 and 5.7 billion by 2050. Such an aggravation could be caused by water contamination, an environmental problem of the highest importance, impacting both people and nature.

The problem – alongside drought, population increase and changes in the water cycle related to global warming – endanger the supply of freshwater for both consumption and other essential activities.

Globally, over 80% of waste water resulting from human activities is discarded untreated into rivers or seas, causing their pollution. A team from Spain’s main research organization, the CSIC, has detected 59 ECs in areas of high ecological value in the country. Farmland and dense urban areas are the biggest sources of pollution.

“Globally, over 80% of waste water resulting from human activities is discarded untreated into rivers or the sea”

From 84% of water samples collected and analyzed, the researchers observed medicines and caffeine, and nicotine in 76%. They also found pesticides and polyfluoroalkyl substances (PFAS, components used, for example, in Teflon, firefighting foam or products used by the agri-food and construction industries and households), as well as other common waste such as cosmetics.

To this list of emerging contaminants, add microplastics, particles less than five millimeters across that are present in all aquatic ecosystems.

Although their small size might suggest the opposite, microplastics represent a significant risk for the health of ecosystems and, potentially, human health, since they can be ingested by aquatic organisms and accumulated in the food chain.

Their presence in water, along with other ECs, underlines the urgent need to review our practices of consumption and waste management to protect our water resources.

What are emerging contaminants?

Imagine this is your night-time routine. You take a medicine from a sachet and dissolve it in a glass of water. You finish loading the dishwasher with the dinner plates and this glass you have just used, add the corresponding detergent and switch it on. Then you go wash your face, wipe the rest of your make-up off with soap and water, and rub in some cream. You wash your hands because you don’t like the slippiness of your fingers afterwards and the remains go down the sink.

Through all these small and routine tasks, you have disposed of emerging contaminants in the environment. These are chemical substances that are ultimately detected in water and whose presence can be a risk to nature and human health.

Although they are called ‘emerging’, there is nothing really new about them. What’s new is the development of the technology to detect and measure them in water.

They are made up of medicines, cosmetics, cleaning products, pesticides, and so on; products that are part of our daily routines, and as such it is we who introduce them into ecosystems.

Hundreds of tons of these products are manufactured every year worldwide and this is on the rise due to the growing consumption by a constantly increasing population and the discovery of new compounds.

The problems ECs unleash on nature

Although low in concentration, the effects of these substances can be biologically important and produce distinct negative effects on ecosystems and human health.

ECs include many substances that can act as endocrine disruptors, i.e. they have the capacity to limit, block or interfere with endocrine system hormones of organisms, producing noxious effects at the physiological level, which can affect reproduction, the metabolism, behavior, responses to stress and the immunological system.

“Their effects of these substances can be biologically important and produce distinct negative effects on ecosystems and human health”

Medicines are bio-active products, designed to produce a determined response in the individual receiving them. When these products reach the tissues of other organisms, distinct from those they are designed for, such as fish, amphibians, etc., their effects can be adverse. This is also demonstrated by the presence of small concentrations of medicines in water used for irrigation that alter the development of roots and crop growth.

Did you know that up to 90% of medicines that we take are eliminated whole through urine? The disposal of pharmaceutical products in water is inevitable to a degree, but each new study reveals the seriousness of the problem. Research in Australia found 69 different medicines in over 190 invertebrates in the streams near Melbourne. The researchers calculated that a platypus feeding on these animals would be receiving half of the daily doses of anti-depressives prescribed for humans.

As for antibiotics, whose excretion to the environment can reach up to 125,000 tonnes per year, the most immediate effect is the progressive reduction in their effectiveness. All these products, once they have entered the food chain, can end up being ingested by people.

Innovative projects to rid ECs from the water cycle

It is ever more urgent that we take measures to protect water resources through treatment or reuse, technologies key to ensuring water access.

One of our biggest challenges is eliminating emerging contaminants, including microplastics. Wastewater treatment plants are designed to reduce common pollutants in water sources by eliminating suspended solids, organic material and nitrogen and phosphorous before water is reused or disposed of in a river or ocean. EC characteristics, however, mean they are difficult to eliminate during conventional wastewater treatment and they are often detected in the sea, rivers and marine food chain. As such, it is vital we adapt and improve treatment methods so they can also eliminate ECs.

LIFE PRISTINE, innovation in the water cycle

One of the most innovative projects at European level is LIFE PRISTINE, led by ACCIONA. The aim is to design a full-cycle, sustainable solution that eliminates 80% of ECs from water, reducing their concentration below the recommended levels.

It focuses on ECs such as PFAS (the substances in flame retardants, for example), pesticides, pharmaceutical and personal care products, toxins, genes resistant to antibiotics, and microplastics. The project will contribute to strengthening norms and ensuring the use and reuse of water of maximum quality and safety.

The technology employed by LIFE PRISTINE has demonstrated maximum efficiency. It integrates adsorption, nanofiltration and advanced oxidation processes. Along with virtual sensors, and including processes and tools to support decision-making, LIFE PRISTINE will be able to eliminate ECs from the water cycle efficiently.

Our water supply is a precious and limited resource - and it is our responsibility to protect it for future generations. Through the appropriate measures, we can better protect our water in the face of emerging contaminants.

Sources: