The WoW! project has also shown that biochar from cellulose has a huge application potential at STPs. In the WOW! capitalisation initiative, biochar (produced from cellulose) will be activated into activated carbon for elimination of micropollutants at small and medium STP’s. The activated carbon will be used in constructed wetlands as an additional step after the conventional treatment. We give you an update about the latest developments.
Cellulose from Ede (The Netherlands) wastewater treatment plant influent was collected and dried by Cirtec B.V. in summer 2022. Klimafarmer, a company specialized in biochar-based substrates located in Germany, pre-processed the cellulose and proposed three different compositions of biochar looking for the best efficiency: 100% cellulose, 50% cellulose-50% straw and 50% cellulose-50% wood. Those three biochars were activated biologically via fermentation and sent to the University of Luxembourg water-lab for their characterization, before and after the activation. Since the biochar will be used as part of the substrate in constructed wetlands adopted as post-treatment step for Micropollutant elimination, the full assessment of the capacity for the removal of contaminants from water at lab-scale was performed. Adsorption of all biochars was tested in batch and continuous mode for a dye (indigo carmine as model compound) and for different representative micropollutants. In addition, for the biologically activated material, the degradation capacity of the microorganisms itselves was studied separately by cultivation in a liquid medium, and finally, the combination of adsorption+biological degradation was also analysed.
Physical-chemical characterization of the biochar surface was performed by an external company (3P instruments, Germany). This complete evaluation helped to define which of the different non-activated and biologically activated biochar has the highest capacity to remove pollutants and would be the most suitable for the subsequent use in the pilot-scale constructed wetlands, which will be addressed in the following months.
