WheyNot?: Dairy industry waste reuse into biobased resources for the chemical industry

This research is a collaborative project between Water Future, Looop, and MNEXT to address the valorisation of a residual stream that remain after valorisation of whey towards food and feed applications: whey permeate. This permeate is a high-volume but low-quality stream, which is currently used as a filler for mainly animal feed, but with the large amounts produced in NW-Europe it is essential to valorise whey permeate higher in the value chain, for example into a biobased resource which replace fossil-based resources in the chemical industry. To accomplish this, pre-processing steps are necessary to remove minerals. Electrodialysis (ED) can remove unwanted minerals from whey permeate by applying an electric field across its membranes. Using ED, whey permeate is expected to demineralize into a liquid which is suitable for application as biobased resource for various applications. Moreover, the extracted mineral stream can also be reused.
This one-year project aims to quantify and optimize the demineralisation of whey permeates using a lab-scale ED setup to make the whey permeate stream suitable for re-use and thus reduce the environmental impact of this stream. The project involves setting up an ED setup provided by Water Future to treat whey permeates supplied by Looop, assessing the suitability of treated permeate as a biobased resource in the chemical industry and processing the produced mineral streams into new biobased resources. The result of this research will demonstrate the use of ED as a valorisation technique for whey permeates and the integration of multiple processes into a valorisation pathway to transform costly whey permeates into value-added products. MNEXT leads the research development, aiming to potentially establish a recycle strategy for resource recovery in the dairy industry. The results will be presented through educational activities, reports, digital platforms, and conferences to transfer knowledge to a broader audience.

Eindrapportage

WheyNot investigated how industrial whey permeate, a liquid side stream from dairy processing, can be converted into useful biobased products instead of being treated only as waste. The project focused on using electrodialysis (ED), a membrane technology, to remove unwanted minerals from whey permeate. In this way, the treated stream can become more suitable for further fermentation.

Several industrial side streams from Looop were first tested. Whey permeate was selected as the most practical and relevant feedstock because it contained enough useful organic compounds and was easier to process. Initial ED tests showed that many dissolved minerals could be removed effectively, with the removal of one main mineral reaching 90–99%. However, some minerals were still difficult to remove, so an additional pretreatment step was needed. pH-induced precipitation was found to be effective and clearly improved the removal of these difficult minerals before ED. After pretreatment and ED, the treated whey permeate was tested in a fermentation step. The best condition showed that the treated stream could be converted into a biobased product, although the yield was still below the theoretical maximum. This means that the route works at lab scale, but further optimisation is needed to improve the process performance and stability. One less optimised route did not produce the desired product, likely due to inhibitory ion.

Overall, WheyNot demonstrated that a precipitation–ED–fermentation route is a promising pathway for whey permeate valorisation. The project also showed that the mineral-rich side streams may have potential for nutrient recovery or fertilizer-related applications. Follow-up research should focus on improving pretreatment, reducing inhibition, moving towards better controlled fermentation, product purification, and further evaluation of the mineral streams.