Employee walking through a plant at production site in Dormagen, © Covestro
Aerobic biological treatment is the most frequently implemented state-of-the-art method for treating chemical industry wastewater. This means that the energetic potential of organically rich process water streams is not used. On the contrary, the aerobic treatment requires energy consumption itself and thus creates additional CO2 emissions. This is even more significant for streams that need to be incinerated due to organic load or toxicity. In any case those treatment strategies hinder the carbon neutrality goals of the individual chemical companies as well as the EU as such. Therefore, more sustainable strategies are essential and explored in this case study.
Anaerobic treatment of highly loaded streams shows promise, provided inhibiting effects of toxicants are overcome, and efficient separation/conversion of recalcitrant components is achieved. Compared to aerobic routes, the carbon footprint of the treatment (related to aeration and sludge disposal) is reduced. More importantly even, the biogas generation via anaerobic treatment can not only replace fossil energy and be an essential player in the energy transition. It can even – as a methane / carbon dioxide mixture or as biomethane – become a feedstock for various synthesis routes in the chemical industry.