Turning a problem into a solution: Wasser 3.0 studies ways to remove microplastics from water without a filter

Plastic is an important material and a virtually irreplaceable component in many products. However, the breakdown and disposal of plastics after use also goes along with microplastics. At the end of its life cycle, plastic material first ends up in the environment and then comes back to us: According to a study by the University of Newcastle, tiny particles of microplastic can enter our bodies via drinking water or certain foods.

That is why it is imperative to thwart the spread of microplastic pollution. It is also the stated goal of the non-profit company Wasser 3.0 (English: Water 3.0). In this interview, founder Dr. Katrin Schuhen explains how the company's "4th Treatment Step plus" project (German: "4. Reinigungsstufe plus") studies the concentration of microplastics in municipal wastewater treatment plants. The company also delivers a way to remove the harmful substance.

Dr. Schuhen, what is the focus of your project titled "4th Treatment Step Plus"?

Dr. Katrin Schuhen: While some wastewater treatment plants already implement a fourth treatment step to remove micropollutants such as pharmaceuticals, pesticides or PFAS, microplastics are neither regulated by law nor high on the agenda of wastewater treatment or water protection facilities. Yet we definitely know that municipal sewage treatment plants encounter significant microplastics pollution.

Our 12-month long-term study at the municipal wastewater treatment plant Landau-Mörlheim studies both classes of pollutants for the first time: the dissolved organic chemical compounds which include micropollutants, and plastic particulate contaminants. The latter are known as microplastics, referring to fragments of any type of plastic less than 5 mm (0.20 in) in length. Our Wasser 3.0 PE-X® process simultaneously removes microplastics and micropollutants from wastewater.

We also apply our new detection method to track water pollution by microplastics continuously. By adding the data from micropollutant monitoring, we can also continuously adapt and optimize our removal technology. This gives us key data records pertaining to microplastic pollution at a municipal wastewater treatment plant. Due to the lack of standard analytical methods, there have been big gaps in knowledge and data in this area. One of our goals is to close these gaps.

In short, we use our detection method to analyze the real extent of a problem, which we subsequently solve with our removal technology.

Can you explain the technology and how it works?

Schuhen: Wasser 3.0 applies three chemical concepts based on the principles of green chemistry, designed to remove inorganic chemical, organic chemical and microplastic contaminants from water. We always aim for zero pollutants in water. This is also why we called our company Wasser 3.0.

We apply the principle of "clump and skim" to remove harmful microplastics: We use a simple process to add hybrid silica gels that are not harmful to health to the contaminated water. Once stirred, the hybrid silica gels clump together with the microplastics and micropollutants and form agglomerates that resemble popcorn. These float on top of the water and get separated using a skimmer and no filters. One can also use coarse-pored filters for large agglomerates.

The adaptability of the hybrid silica gels is the key to the success of our process. Individual adaptation enables us to create custom solutions for different types of pollution and types of water. We achieve reproducible elimination rates of over 95 percent for microplastics. For micropollutants, we follow the guidelines of the German National Water Strategy, which stipulates a minimum 80 percent removal efficiency for micropollutants by wastewater treatment facilities.

Wasser 3.0 PE-X® is a meaningful and value-added application not only as it pertains to municipal wastewater but also when it comes to industrial processes, surface waters, and systems that use saltwater such as seawater desalination or sea salt extraction. Especially in industrial processes, our implementation immediately stops microplastics from entering the water cycle. At this juncture, we not only close loops in a circular process flow, but our sustainable process design also delivers economic incentives for environmental protection.

The initial findings of the long-term study support this statement. While sewage treatment plants can remove microplastics, they are microplastics emitters at the same time. A fact that should be kept in mind in a quest for solutions that won't spell big problems for future generations.

How will your research findings impact the future of microplastic removal?

Schuhen: The environmental and health risks of microplastics are the subject of heated debates in society. Water purification and its effects on biodiversity, climate change, and public health is an important issue and one that I believe must transition more quickly from problem statement to proactive steps and forward-thinking action. We hope our actionable insights into the detection and removal of microplastics will move the issue higher up on the political priority list, give the problem more visibility and promote faster action.

The successful evaluation completion of our detection solution for continuous process control is a quantum leap in microplastics because it exhibits a much quicker, more efficient, and more cost-effective way to remove microplastics than conventional detection methods. All told, it lends itself to support a standardized approach to data collection on microplastic water pollution. Standardization in this area would have far-reaching consequences for the political discourse pertaining to thresholds and their adoption. The willingness and prospects of a solution means microplastics must become a higher priority on the political agenda.

We also hope to see a shift in mindset when it comes to thermal recycling of sewage sludge. Due to the high pollution levels in sewage sludge, it seems to be a more environmentally friendly and healthy approach compared to its application as a commercial fertilizer. I believe we are missing out on a valuable resource in this case. If the findings of our removal rates are further corroborated, we will enable microplastic and micropollutant removal and facilitate simultaneous sewage sludge protection. This could also yield additional uses in the future.

What are the focal points of your work? What goals are you pursuing in your research over the next years?

Schuhen: The core strategy of our work is to detect| remove | reuse microplastics and micropollutants in our water in a holistic manner. Our systemic approach navigates a framework geared towards the common good as it pertains to research, education, communication, and technology development.

The 4th Treatment Step plus in municipal sewage treatment plants is a milestone for us and a key lever for water without microplastics and micropollutants. Another milestone is to prevent microplastics and micropollutants from entering the water cycle in the first place, resulting in the need to remove them from the wastewater in municipal sewage treatment facilities. We are collaborating with various industry sectors in flagship projects dealing with microplastic-contaminated process and wastewater. We are adapting our Wasser 3.0 PE-X® process in feasibility studies, are continuing to evaluate our detection method and ways to reuse so-called waste products.

In the years to come, research of microplastics and micropollutants will continue to grow in importance. Not only do we require new technologies that foster sustainability and help drive circular economy, but we also urgently need a more comparable and reliable database to engage policymakers and industry to inspire action.

The key to success is applied research that embraces innovation transfer, education, and public awareness. Wasser 3.0 covers these aspects. After all, we don't just need one but many solutions to eliminate microplastics and micropollutants from water. These must come from policymakers, industry, science, civil society, from local and international stakeholders, from individuals and groups of people.