The authors have demonstrated the following key points:•The recycling of the Bortezomib
flocculant back into the RT digester resulted in a significant improvement in dewatering performance compared to the control digester. At the highest constant polymer concentration tested, the CST values for flocculated samples for the RT digester were over 6 times lower than the corresponding values for the control digester. The filtrate quality results, as measured by TSS, were in good agreement with the measured CST values.•There exists an opportunity to decrease the overall consumption of polymer flocculants through judicious selection of the dose of polymer flocculant that is used both for the thickening and end-stage dewatering processes in RT digesters.•There were no significant changes in biogas methane composition for the RT and control digesters. Also, the RT digester had the same biogas yield as the control digester and therefore had a significant improvement in overall biogas productivity. This is most likely due to an improvement in the fed VS destruction from recycled solids in the RT technique. It indicates that the short term oxygen exposure during the thickening process did not discernably inhibit the methanogenic activity and also that the recycled polymer does not appear toxic to the anaerobic
microorganisms.•This lab-scale RT technique is an effective tool to study RT processes and thus is ideal for addressing the current knowledge gaps in the field. It is suitable as a screening tool for determining the
critical process parameters that determine dewatering performance in polymer-induced flocculation processes.