Biological wastewater treatment

Water is undeniably the most important single foodstuff. Water management – i.e. easy access to clean water, a guaranteed supply of water, the installation of hygienic sanitary systems and efficient, compact wastewater purification – is therefore one of the major global challenges facing this century.

To cope effectively with these major challenges, Fraunhofer IGB is working on an innovative semi-decentralized water and wastewater management. Geographical and climatic factors such as the (seasonal) shortage of water in arid and semi-arid areas are also taken into consideration.

In comparison to thermical and chemical processes, biological processes are more efficient and economic for the elimination of organic loads from wastewater and sewage. In combination with membrane technology especially efficient processes can be built up.

For over two decades, Fraunhofer IGB develops biotechnical and membrane processes for the purification of municipal and industrial wastewater. Additionally, we offer the economic optimization of sewage plants.


Biological wastewater purification processes and reactor concepts


Municipal and industrial wastewater treatment plants

Examination of a biobased and biodegradable flocculant

Wastewater from agricultural production, such as wine and olive oil processing, affect local wastewater treatment plants with their large organic load especially during harvest season. To purify the wastewater before the biological treatment stage, flocculants are commonly used, such as metal ions like iron or aluminum salts or synthetic polymers (e.g. polyethyleneimine). The residue of these substances require intricate disposal processes and hinder the further utilization of water and sewage sludge as resources. Typical wastewater components, particularly tannins and phenolic derivates, are not easily biodegradable in the biological treatment stage and are also toxic to the microorganisms in the aeration tank.

New flocculant: adaptable to the specific wastewater strain

In the La ChiPur project of Fraunhofer IGB, a biobased flocculant was developed, which is based on a matrix of chitosan derived from food production waste and functionalized with the enzyme laccase, an oxidoreductase.

By varying the composition, the flocculant can be tailored to the specific load of the wastewater and the existing purification infrastructure. An additional advantage is that the residue of the biobased flocculants is biodegradable, simplifying further utilization of sewage sludge, for example, by recovering nutrients. The technology is intended to be directly applicable at the source, i.e. in agriculture or wineries, allowing them to save expenses on wastewater disposal by pre-treating the wastewater before it enters the local sewage system.

Purification performance of functionalized chitosan using the example of rinsing water from red wine production
© Fraunhofer IGB
Purification performance of functionalized chitosan using the example of rinsing water from red wine production

January 2021 – December 2023


Treatment of complex process wastewater with bifunctional biobased flocculant

The aim of the LaChipur project is to develop a biobased and functionalized flocculant for the efficient purification of seasonally occurring complex agro-industrial wastewater using residual materials from the food industry. The sustainable flocculant should be customizable to the respective load by varying the composition and thus show optimized efficiency.