Water is the basis of all life. Nevertheless, according to the World Health Organisation (WHO), one in four people still do not have access to clean drinking water. In many cases, waters are polluted, even in Europe. Last year, a master’s thesis in bionics at the Faculty of Technology and Bionics dealt with energy-neutral wastewater treatment. For almost four months, HSRW graduate Álvaro Burgos was a regular visitor to the faculty’s laboratories. There, he developed and tested three different material formulations for biocompatible polymer composites, known as hydrogels. These are crucial for the operation of an eco-fermenter system for wastewater treatment. He was supervised by Dr Christoph Heß, Professor of Non-Metallic Materials, and Oliver Fromm, technical assistant.
Alvaro developed the idea of a modular eco-fermenter system for decentralised wastewater treatment. Not only was this the subject of his master’s thesis at HSRW, but it also led to the founding of EKOWAI TECH in Chile to bring this technology to market.
Material development
The core of the eco-fermenter system is based on biocarriers. These serve as a carrier material for bacteria, which are essential for cleaning and filtering dirty water. Standard biocarriers are usually made of plastic, but Alvaro prefers to use hydrogels. In his research, he therefore focused on developing and testing three different material formulations made of biocompatible polymer composites to determine which one had the largest surface area and stability in water. His theory was that the larger the surface area of the material, the better its purification performance.
‘If we understand the structure of different materials, we can draw inspiration from nature and imitate it,’ says Alvaro, describing his approach.
Taking a closer look at the material composition
The hydrogel was modified with various microscopic fillers. ‘Changing the filler alters the internal structure of the material, creating a new composite material that can be examined,’ he explains. He used these materials to produce sample solutions, which were analysed using the faculty’s scanning electron microscope (SEM). Among other things, SEM allows users to visualise surfaces in high resolution.
With the help of the SEM, Alvaro reached the level of microporosity. He was able to clearly observe the change in the internal structure of the material.
Some formulations collapsed, meaning they failed, while our successful formulation maintained a complex, highly porous structure that is ideal for colonisation by bacteria.’
The hydrogel that proved to be suitable is now being used in a more practical experiment.
From theory to practice
The next steps for Alvaro and EKOWAI are therefore to precisely determine the actual surface area of the biocompatible polymer composites and to test the material with wastewater. ‘My research work on biocarrier technology has shown promising results, but we are now in the critical phase of research validation,’ explains Alvaro. Validation studies are currently underway, including the development of monitoring systems for real-time performance measurement. Physical prototype development of the eco-fermenter system is also progressing. The pilot reactor has been completed and is currently in the start-up phase, in which the biocarriers are being colonised with microorganisms.
‘If our validation confirms the expected performance, we aim to have commercially viable modular systems with a capacity of 0 to 20 m³/day available by the end of 2027 for operation in areas such as craft beer breweries and food processing plants.’