AkzoNobel Specialty Chemicals’ broad range of production processes result in a variety of wastewater streams which often contain both salt and organic matter. As a leader in sustainability, we are looking for improved methods to purify our wastewater streams to decrease any impact on the environment. In our vision of truly circular chemistry, we would be able to reduce the organic matter content, reuse the water, and sell the salt as a valuable raw material, thereby closing the water loop in our factories.
The composition of our wastewater streams varies significantly. Many of them contain organic matter (expressed as chemical oxygen demand, or COD), much of which we can easily treat biologically. However, a major challenge is the presence of non-biologically degradable organic residues (expressed as hard chemical oxygen demand, or hard-COD), often in combination with high amounts of salt (typically potassium or sodium salts of chloride or sulfate). We also have some sites where we want to reduce the amount of organically-bound nitrogen in our wastewater streams. Lastly, within our businesses the acceptance levels of COD in wastewater range widely (from 200ppm to 1ppm). We need to broaden our repertoire of wastewater treatment solutions to deal with these different streams more effectively.
The main challenge with our wastewater streams is the high amount of salt (ranging from 5 to 25%), which creates challenges for biological wastewater treatment. Moreover we find that a significant part of our COD after biological treatment originates from residues from the microbes themselves (hard-COD). Having microbes that can better resist high salt concentrations and/or have a longer lifespan would make the process more effective and efficient.
For the organically-bound nitrogen waste (which is not always in combination with high salt concentrations), the wastewater is complex and batchwise production results in significant variations over time. These variations lead to challenges related to efficiency, toxicity, sludge resilience, and treatment plant design; thus far, these challenges have hampered the implementation of an effective biological treatment approach.
We are looking for solutions in 4 specific areas:
Solutions could involve the biology of microorganisms, chemical or technological methods, or even ways to better monitor and control the composition of our wastewater effluents in order to more effectively control the biological wastewater treatment feedstock. Ultimately we would like to reduce the COD in our waste streams enough to be able to use the salts as a raw material for other processes.
We are not looking for existing technologies like evaporation-based techniques, incineration, or the long-established chemical oxidation techniques, unless there is a proven step-change improvement from a cost and sustainability viewpoint.
If you think you have the solution to help us make our wastewater organics-free so we can reuse it in production, we welcome you to join our Challenge on our Imagine Chemistry Challenge platform - open from January 10 - for open and collaborative innovation.