Pharmaceuticals – synthetic or natural chemicals used in human and veterinary drugs – are a great boon to society. However, as humans and livestock naturally excrete these chemicals after ingesting them, they eventually end up in wastewater.

Conventional wastewater treatment technologies are currently unable to remove all of these chemicals, and small amounts end up accumulating in Europe’s rivers, lakes and ground water.

Some of these chemicals have been detected in drinking water, though at tiny concentrations “very unlikely” to pose an immediate risk to health, says the World Health Organisation (WHO).

Even so, the best strategy is to remove all pharmaceuticals from wastewater, preventing them from entering the water system in the first place. The EU-funded Endetech project, which ended on 31 January 2015, has shown the way by demonstrating that a purification system using enzymes – proteins that act as catalysts for chemical reactions – could be developed to neutralise potentially harmful pharmaceuticals – antibiotics, hormones and endocrine disruptors.

“Endetech demonstrated in the lab that such a system could work,” says project coordinator Pierre-Alain Bandinelli of Da Volterra in France. “Enzymes could be a natural way of removing pharmaceuticals from wastewater. While the technology is still in early stage development and needs to be scaled up, it should be considered as part of the arsenal of approaches used in treating wastewater.”

Targeting endocrine disruptors

Endetech began by developing tests or assays that identified new enzymes able to inactivate four antibiotics that are not easily captured by conventional water treatment technologies – tetracycline, erythromycin, sulfamethoxazole and ciprofloxacin.

The project’s researchers then developed a way to incorporate these enzymes on beads and filtering membranes.

In the Endetech concept, wastewater would flow along the beads or through the membranes, where the enzymes would neutralise the targeted pharmaceuticals.

The researchers also identified enzymes to neutralise tetracycline, an important and commonly used antibiotic for humans and livestock. Lab tests on wastewater samples showed the enzymes removed some of the tetracycline traces after one day – a sign that Endetech’s research was on the right track.

The project also tested other enzymes against endocrine disruptors. This class of drugs can interfere with the endocrine systems of humans and animals, potentially leading to diseases such as cancer, birth defects and other health problems. Endocrine disruptors are also known as ‘gender benders’, as they can supress the testosterone hormone in males, leading to abnormalities.

The lab tests showed that Endetech’s technology reduced endocrine disrupters in wastewater – a “promising result”, says Bandinelli.

Next steps

Endetech’s research has provided researchers with a method to search for and pinpoint enzymes that neutralise specific pharmaceuticals. The project also developed a method of incorporating these enzymes in beads and membranes for use in treatment plants.

More research is needed to make the technology more effective and to scale it up for use in treatment plants, says Bandinelli. Since the project has just ended, the partners involved have not yet made a decision on the way forward and are considering further development of the technology.

He adds: “Taking action to remove this type of environmental pollution is becoming a necessity as European and national regulations are becoming stricter to ensure water remains safe to drink and to protect the environment.”

Below picture of pilot reactor used in ENDETECH project