Towards a biomolecular sensor for hindered settling velocity

We aim to answer whether it is possible to predict activated settling velocity based on biomolecular observations. Laboratory- and full-scale experimental activated sludge data retrieved combined information on the relative abundance of putative settling determinant Cand. Microthrix parvicella, Chloroflexi and Thiothrix as well as the associated hindered settling velocity parameter v0/rH. A new predictive tool for settling velocity was developed using laboratory- and full-scale
measurements. Validation of the simulation model was carried out using a long-term performance and settling simulation of the Kloten-Opfikon activated sludge water resource reclamation facility (WRRF), Zürich, Switzerland. Experimental observations combined with dynamic simulation results indicate that Microthrix abundance can directly associate with hindered settling velocity. We also demonstrate that Cand. Microthrix is an ideal candidate to represent filamentous microbial populations, additionally including Chloroflexi and Thiothrix at significantly higher relative abundances than Cand. Microthrix.