Ga naar hoofdinhoud

Technology & Innovation Campagne University Fund

Text Jeroen van Aken

Safe drinking water
through bacteria

Drinking water from groundwater wells in Bangladesh often has a too high concentration of arsenic. According to estimates, in the worst affected areas one out of 10 adults die from the effects of arsenic poisoning. Engineer Roos Goedhart is researching how bacteria can help remove arsenic in drinking water treatment and as such giving millions of people access to safe drinking water.

Read more

Arsenic is considered a heavy metal. It is contained naturally in soil and can end up in groundwater. The long-term ingestion of arsenic raises the chance of contracting cancer. The standard of the World Health Organization (WHO) is that the concentration of arsenic in drinking water may not exceed 10 micrograms per litre.

“The concentration of arsenic in groundwater varies strongly across locations,” says Goedhart. “There are a few places in the Netherlands where the concentration in groundwater is slightly elevated. After purification, the international WHO standard is achieved. Bangladesh and other countries such as Vietnam, India and the United States have locations with more than 100 or even more than 1,500 micrograms per litre.”

In terms of the quality of its drinking water, the Netherlands sets very high goals and continuously invests in treatment. “A better way of removing arsenic from groundwater would both further improve the quality of the drinking water here and make the treatment process more sustainable. Even bigger gains could be made in other countries. In Bangladesh for example, there are still life-threatening quantities of arsenic in drinking water. There are treatment plants, but not all of them work that well.”

‘My goal is to find an alternative for the chemicals and find a natural solution instead of a chemical one’

Groundwater treatment

The basic principle of groundwater treatment in the Netherlands and Bangladesh is similar. The first step is to pump up groundwater and then oxidise it to start chemical reactions. The water is then filtered, often through a container of sand. The water is purified by both chemical and biological reactions in the filter layer. “We still do not know exactly what happens with the arsenic during the treatment process. The process partly removes the arsenic, but the extent to which this is done varies enormously across plants. I am trying to find out why. We want to know which reactions are responsible for arsenic removal and how we can optimise these processes.” 

researcher profile

© Universiteitsfonds Delft

Name Roos Goedhart

Expertise Water treatment (Civil Engineering and Geosciences)

Working on better understanding how bacteria remove arsenic during groundwater treatment

Potential applications simple way to make safe, arsenic-free drinking water worldwide

Donation spent on extending the fieldwork and deploying more microbiological expertise

Why TU Delft?

“TU Delft is a recognised entity in water treatment internationally. You see this if you visit other places in the world and we can be very proud of that. I learned everything I know about water treatment at TU Delft, and the laboratory is well equipped to carry out my tests. I will build a small version of a drinking water treatment plant right here in our Waterlab. This enables me to closely track and measure the chemical and biological processes. It is a unique set-up in the Netherlands. This research fits the modern TU Delft well. First understand the problem and access the whole picture, and then start working on a technical solution. In my case I am working on improving water treatment using natural processes with as few interventions as possible.” 

Roos Goedhart seeks a natural alternative to chemical purification.

© Roos Goedhart

Natural alternative

At present, if the treatment process does not remove enough arsenic from the water, chemicals are added to optimise this process. “Bangladesh often has small-scale treatment systems. These can lack the manpower, infrastructure and sometimes the chemicals to run this extra purification step. My goal is to find an alternative for the chemicals and find a natural solution instead of a chemical one. This could be used in both the Netherlands and in Bangladesh. We want to find out which bacteria live in these filters and which of them contribute to arsenic removal. The samples of the filters we collect need to be analysed with special microbiological techniques. Some of these are not available at our faculty. With extra budget, I can start applying these techniques myself, and bring this knowledge back to our group. Better analysis ensures more knowledge and a better outcome of the research.”

Safe drinking water

“Water scarcity and contaminated drinking water is an ever increasing issue. Groundwater is a wonderful source of water as it is more protected from external impacts such as pharmaceutical residues and PFAS. But groundwater can be contaminated with toxic arsenic, which has to be removed. If we can find a simple solution for this, there will be a lot more safe drinking water available.”

Extend fieldwork

“In Bangladesh we have measured different types of filters in water treatment plants to monitor arsenic removal. Additional budget will help us extend the fieldwork, also to other countries. This will help us gain understanding in the processes in different parts of the world, making our research even more relevant.” 

Tech for Impact 2024

will you join us?

Delft University Fund supports projects that have an impact on society, such as Roos Goedhart’s research. You can contribute to this. Apart from the arsenic research, three more projects by top researchers are in the spotlight.

Molten salts

Physical chemist and materials scientist Dr Anna Smith (Applied Sciences) is working on a prediction model of the properties of molten salts as nuclear fuel. A new type of nuclear reactor such as the molten salt reactor is safe and sustainable and could make an important contribution to the energy transition. Donations will allow Smith to build a new testing set-up at atomic scale.

Digital twin hart 

There are around 1.7 million people in the Netherlands with cardiovascular disease. Dr Mathias Peirlinck (Mechanical Engineering) is working on a digital twin of the heart. 

He wants to better understand the mechanism of heart disease and predict the best treatment. Donations he will spend on additional research into the functioning of heart tissue.

CO2 from the air

To be climate neutral by 2050, the Netherlands must reduce greenhouse gas emissions. Chemical engineer Dr David Vermaas (Applied Sciences) is developing a technology to extract CO2 from the air using electrochemistry and renewable electricity. Alumni donations will allow him to build a demonstration model.

Which Tech for Impact 2024 project can count on your support?

Check out the projects

Tech talk

The four researchers each provide a one-hour online Tech Talk. Roos Goedhart did so on 29 May. On 27 June from 16:00 to 17:00, David Vermaas talks about his research. After the summer, Anna Smith and Mathias Peirlinck will have their turn. All talks can be listened to via via https://www.tudelft.nl/techforimpact