Researchers want to use bacteria to remove PFAS from wastewater.
Økologisk NuPFAS are a large group of man-made fluorinated substances that have spread into soil and aquatic environments. Many of these substances are extremely difficult to break down because of the strong chemical bonds between carbon and fluorine. Today, PFAS can be removed from water using methods such as activated carbon and membrane filtration. However, these methods do not necessarily break down the substances; instead, they collect them in filters or concentrated residual products that must subsequently be handled. In addition, pharmaceutical residues and other contaminants can pass through traditional treatment processes and end up in the aquatic environment. Researchers from Aarhus University’s Department of Biological and Chemical Engineering will therefore investigate whether bacteria can help break down several types of pollution in the same treatment process. To this end, they have been awarded DKK 7.2 million by the Independent Research Fund Denmark. The aim is to develop a new method that harnesses bacteria’s natural ability to produce chemical compounds capable of breaking down various pollutants, including PFAS, pharmaceutical residues and nitrogen. Aarhus University writes this in a press release. “We want to develop a process in which bacteria produce the chemical substances needed to break down pollutants that traditional wastewater treatment has difficulty removing. PFAS is an important target, but we will also investigate whether the method can be used to break down pharmaceutical residues and other contaminants,” says Professor Barth F. Smets, who is leading the project. **Bacteria to do the chemical work** When certain bacteria metabolize nitrogen compounds, they produce reactive oxygen and nitrogen species, also known as ROS and RNS. These compounds can react with other molecules and alter their chemical structure. Professor Barth F. Smets has previously documented that bacteria produce these compounds. In addition, Associate Professor Zongsu Wei has shown that reactive nitrogen species can break down the PFAS compound PFOA in a chemical system in the laboratory. The researchers will now attempt to combine the two processes. “We know that bacteria can produce the reactive compounds, and we have shown that these compounds can break down PFOA in a chemical system. Creating the necessary conditions using bacteria will be difficult, and this is actually the project’s greatest scientific challenge,” says Zongsu Wei. **Building on existing treatment processes** The researchers will also map which substances are formed during the breakdown process in order to investigate whether the process creates potentially harmful by-products. In the longer term, they hope to integrate the technology into existing treatment plants, where the method could potentially reduce the need for more energy-intensive chemical treatment processes. “If we succeed, we could have a new and more resource-efficient method for breaking down PFAS and other persistent environmental toxins. But first we need to demonstrate that the bacteria can produce enough reactive compounds for the process to work effectively,” says Zongsu Wei.
PFAS are a large group of man-made fluorinated substances that have spread to soil and aquatic environments. Many of the substances are extremely difficult to break down due to the strong chemical bonds between carbon and fluorine.
Today, PFAS can be removed from water using, for example, activated carbon and membrane filtration. However, the methods do not necessarily break down the substances, but collect them in filters or concentrated residual products that subsequently have to be handled. In addition, pharmaceutical residues and other environmentally hazardous substances can pass through traditional treatment processes and end up in the aquatic environment.
Researchers from Aarhus University’s Department of Biological and Chemical Engineering will therefore investigate whether bacteria can help break down several types of pollution in the same treatment process, and for this they have been granted DKK 7.2 million from the Independent Research Fund Denmark. The goal is to develop a new method that exploits the bacteria’s natural ability to produce chemical compounds capable of breaking down various pollutants, including PFAS, pharmaceutical residues and nitrogen. Aarhus University writes this in a press release.
"We will develop a process in which bacteria produce the chemical substances needed to break down pollutants that traditional wastewater treatment has difficulty removing. PFAS is an important target, but we will also investigate whether the method can be used to break down pharmaceutical residues and other environmentally hazardous substances," says Professor Barth F. Smets, who leads the project.
Bacteria to do the chemical work
When certain bacteria metabolise nitrogen compounds, they produce reactive oxygen and nitrogen compounds, also known as ROS and RNS. These compounds can react with other molecules and change their chemical structure.
Professor Barth F. Smets has previously documented that bacteria produce these compounds. In addition, Associate Professor Zongsu Wei has shown that reactive nitrogen compounds can break down the PFAS compound PFOA in a chemical system in the laboratory.
Now the researchers will attempt to combine the two processes.
"We know that bacteria can produce the reactive compounds, and we have shown that the compounds can break down PFOA in a chemical system. It will be difficult to create the necessary conditions using bacteria, and this is in fact the project’s greatest scientific challenge," says Zongsu Wei.
Building on existing treatment processes
The researchers will also map which substances are formed during the breakdown, in order to investigate whether the process creates potentially harmful residual products.
In the longer term, they hope to integrate the technology into existing treatment plants, where the method could potentially reduce the need for more energy-intensive chemical treatment processes.
"If we succeed, we can develop a new and more resource-efficient method for breaking down PFAS and other difficult-to-degrade environmental toxins. But first we need to show that the bacteria can produce enough reactive compounds for the process to work effectively," says Zongsu Wei.