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Case Study 3: Chemical Industry

Employee walking through a plant at production site in Dormagen

Employee walking through a plant at production site in Dormagen, © Covestro

 
Operator: COVESTRO
Modules combined: Module 2 combined with other Modules
Focus: chemical energy and water recovery

 

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.

 

In the CORNERSTONE systems integration plan:

  • Pre-treatment: The relevant streams will be comprehensively mapped, and pretreatment requirements identified based on components that may impact anaerobic processes. Technologies for pretreatment, such as separating volatile solvents or selectively decomposing recalcitrant pollutants, will be assessed, and developed.
  • Anaerobic digestion: An anaerobic membrane bioreactor (AnMBR) (Module 2) combining anaerobic digestion with membrane separation will be explored to achieve maximum organic conversion into biogas with positive net energy production.
  • Post-treatment: The characteristics of the liquid digestate will be assessed for further valorization options, focusing on water and solutes recovery using existing knowledge and state-of-the-art technologies.

Added value for society

  • Energy from waste and reduction of direct carbon emissions
  • Generate CH4, an alternative to fossil-based fuels
  • Carbon footprint reduction
  • Resource recovery, using biomethane as feedstock for biobased chemicals and products
  • Reduce dependencies on incinerators