By Mr. Erik Roesink, Founder and CTO, NX Filtration

Climate change is causing more extreme weather situations, such as strong local rainfalls or longer periods of droughts. In many places in the world the availability of groundwater is getting more and more restricted. Even in a country like the Netherlands, where water is traditionally abundant, water utility companies are struggling to supply to new industries and for a growing population.

Locally available alternative water sources for groundwater are surface water or biologically treated effluent from wastewater utilities. However, these sources contain significantly higher concentrations of contaminants and necessitate intensive treatment to meet industrial or potable water qualifications. This gives rise to a need for technologies that address these issues in a robust, energy friendly manner with a low environmental footprint.

It is paramount to realize on a global scale 80% of all the wastewater, including pharmaceutical residues, is discharged in the environment without being treated at all. And the effluent of the 20% that is treated, typically biologically, still contains alarming amounts of pharmaceutical drugs and resistant bacteria.

Recently, the World Economic Forum pointed out (http://ow.ly/P1wa50HXFL4) that pharmaceutical drugs are present on dangerous levels in almost all world’s rivers, posing a threat to the environment and human health. One should realise that the origin of these drugs in these rivers is primarily from normal use by humans, and secretion of human waste through municipal sewage systems. The highest concern of the World Health Organisation is the threat of antimicrobial resistance, which is expected to cause 10 million of deaths annually by 2050 (https://healthpolicy-watch.news/no-time-to-wait-amr-could-cause-10-million-deaths-annually-by-2050-warns-un-report/). Still, the unwanted consumption of pharmaceuticals will further increase due to population growth and economic development. In that light, it is paramount to realize on a global scale 80% of all the wastewater, including pharmaceutical residues, is discharged in the environment without being treated at all. And the effluent of the 20% that is treated, typically biologically, still contains alarming amounts of pharmaceutical drugs and resistant bacteria.

If we limit ourselves to Europe, we see that politics are focussing strongly on preventing micropollutants at the source and less on removing them from biologically cleaned effluent. Though I am fully supporting the prevention approach, we must also realize that this route will not avoid the predicted effects by WHO, as e.g., the enormous number of deaths caused by AMR in 2050. Only in the Netherlands more than 200 tons of residual medicines are disposed in surface waters through municipal wastewater effluent, and since this number is based on officially registered sales of medicines, the realistic total number is probably much higher, as leaching by diffuse sources and animal medicines and illegal drugs have not been considered. Elimination and prevention, though important, will not be the complete solution and take too much time, so removal technologies need to be implemented as well.

Good news is that efficient technology to mitigate these additional challenging pollutants is available, as the newest generation of membrane technology can remove all these challenging components producing a direct re-usable permeate quality.

In most European countries, there is no legislation that regulates disposing pharmaceuticals, or broader, chemicals of emerging concern (CEC), or organic micropollutants (OMPs). Today, the only country with legislation in place on regulating CEC is in Switzerland. As a result of this legislation many wastewater treatment plants in Switzerland are (being) upgraded using either oxidation (O3), and/or adsorption (activated carbon) to remove (partly) OMPs. Though we do see less disposal of OMPs, the resulting product is not ready for re-use, since AMR, viruses, bacteria, nano and microplastics, PFAS, and still OMPs are present in the effluent.

Good news is that efficient technology to mitigate these additional challenging pollutants is available, as the newest generation of membrane technology can remove all these challenging components producing a direct re-usable permeate quality. Hollow fiber nanofiltration membranes as a direct treatment or in combination with advanced oxidation processes (AOPs) have tremendous potential due to their (combined) extreme low energy and chemical consumption.

Legislation could be an enormous opportunity and inspiration to stimulate the water boards to speed up the improvement of their wastewater treatment plants across Europe, e.g., by implementing the newest generation of membrane technology to avoid disposing almost all earlier mentioned treating components. Next to the environmental and health benefits another very important advantage is that the treated effluent is then ready for high quality re-use applications, and do not pollute the surface, anymore. Of course, re-use is not a new concept. It is already effectively done in California, Singapore and many other places around of the world. But in Europe only 2% of the municipal effluent is re-used, leaving this an enormous potential water source unused today. When realizing that in many places in Europe further economic growth is already struggling with the availability of water, we should also realize that water reuse is also important to unleash this economic potential, which is still not always on the political agenda.

Currently, we are investing billions of dollars in the energy transition to speed-up the transition from fossil to more sustainable energy sources to cope with the challenges of climate change caused by the strong increase in temperature rise. However, the attention for and the importance of the water transition is neglected completely in this perspective. As for energy we have several alternatives, however there is no alternative for water! If we do not start investing in wastewater reuse regulation changes and technology to make surface water safe, all the efforts in energy transition will be wasted, because water shortages will limit economic development and signifyingly effect the health of our population.

We are entering in the so-called “water transition”, as we are in a “water crisis” already, meaning that the use of groundwater as the sole source for high quality water is behind us. We must focus on the efficient and safe use of surface water and the re-use of biologically treated effluent as sources for high quality water. The full-scale application of new technologies such as the new generations of membrane filtration, cannot wait until politics has agreed on legislation. We need to act now for the best water quality and sufficient quantity of water!

About the Author

Mr. Erik Roesink started his membrane career already in the seventies at the University of Twente, where he did his PhD in the late eighties. This work on development of hydrophilic hollow ultrafiltration membranes, formed the basis of X-Flow, of which Erik was one of the co-founders.

In 2013 Erik was then appointed as a part-time professor membrane technology of the University of Twente. During that time, he started to work on the development of new generation hollow fiber nanofiltration membranes. These nanofiltration membranes are highly selective for low molecular weight organics, so-called micropollutants, but allow certain minerals to pass, so high operation pressures and also remineralization are avoided.

Due to the tubular nature of these nanofiltration membranes the hydrodynamics are very well controlled resulting in a simpler process setup and a lower energy consumption compared to conventional membrane technology. Due to the strong low fouling character and the tubular geometry low chemical consumption during operation is required. Based on this technology he founded NX Filtration in 2016.