A new polystyrene-latex-based and EPS-containing synthetic sludge

Since the living microorganisms in activated sludge continuously change, it is difficult to conduct controlled experiments and achieve reproducible results for evaluating sludge characteristics. Synthetic sludge, as a chemical surrogate to activated sludge, could be used to investigate the sludge physicochemical properties, and it is desirable to prepare synthetic sludge with similar structure and properties to real activated sludge to explore the flocculation and settlement processes in activated sludge systems. In this work, a high-strength synthetic sludge was prepared with functional polystyrene latex particles as the framework and extracellular polymeric substances (EPS) to modify its surface. The flocculation and settling characteristics of the microspheres and the prepared synthetic sludge were tested. Compared with other three functional polystyrene latex microspheres, the synthetic sludge prepared with EPS-modified polystyrene latex microspheres showed good settling characteristics and a significantly higher strength. They could be used for studying the physicochemical properties of activated sludge.