LaChiPur – Treatment of complex process wastewater with bifunctional biobased flocculant

Wastewaters from wine and olive oil processing contain a complex organic load that poses major challenges for wastewater treatment plants due to shock loads during the harvesting season. For example, the phenols contained in the wastewater are toxic to microorganisms in wastewater treatment plants, resulting in extended aeration times and thus increased energy consumption for treatment. In primary treatment, flocculants can help to remove suspended solids and particles as well as impurities adhering to them.

Flocculants promote the formation of larger "flocs" that sink to the bottom or float on the surface. Usually synthetic polymers are used here. Since their residues are not biodegradable, the resulting sludge must be disposed of at great expense. Highly technical solutions are often too costly and complex due to the strong seasonal fluctuations. Flocculants capable of both reducing seasonally increased loads of wastewater and oxidizing phenolic compounds may offer an alternative to overcome the aforementioned challenges.

New flocculant: biobased, functional, customizable

In the Fraunhofer-funded project LaChipur, we at the IGB have developed a biobased and functionalized flocculant which can be used to efficiently purify seasonal wastewater. The flocculant is made from residues from the food industry.

The completely biobased technology, which uses chitosan as a matrix and the enzyme laccase, exhibits flocculation performance that is comparable to conventionally used metal salt-containing coagulant or fossil-based flocculants (e.g. polyethylenimine) for complex, seasonal agro-industrial wastewater. In addition to its flocculation properties, the flocculant developed in LaChipur can also oxidize phenols, reducing toxicity to microorganisms in the aeration tank and ultimately reducing energy use. Further advantages are offered by the specific adjustment of the composition depending on the application and load.

For producers of agricultural products, such as wineries or olive mill operators, as well as for wastewater treatment plant operators, the sustainable flocculant opens up new opportunities for action to respond to seasonally specific requirements for wastewater treatment. In addition to the savings in energy for aeration of the aeration basin, savings in sewage sludge disposal can be expected. The use of locally produced recyclables from food production ensures a sustainable supply – without the dependencies of complex international supply chains.

Partners sought for further development

Based on the first promising results, we want to further optimize our product with SMEs that sell or produce flocculants, as well as companies that produce waste containing chitosan, e.g. mushroom growers or biotechnology companies.

Currently, the focus is on the German market. However, the Mediterranean region (e.g. olive mills) is also being investigated as part of the project. In the long term, we aim to open up further international markets (wastewater from the textile industry) and applications (drinking water extraction).