Full-Scale MBR Monitoring – Activated Sludge Filterability vs. Plant Performance

Membrane bioreactors (MBR) are an efficient and widely used wastewater treatment and reuse technology. Despite their significant rise in popularity and applicability there are still a number of important knowledge gaps and operational bottlenecks which need to be addressed. Thus, advancing knowledge about operational parameters, interactions between them and their influences on plant performances is fundamental and essential for the future of MBR technology. This article describes the results of comparative analysis of activated sludge filterability, ullscale operation and overall performance based on the case of three full-scale membrane bioreactors. On-site experiments were performed during summer and winter periods to cover seasonal temperature fluctuations and to monitor the effect of temperature on activated sludge quality and filterability. Activated sludge filterability was qualified mainly as good or moderate, besides special events when filterability was poor. The study shows that the performances and the operations of the full-scale MBR plants can be affected by abrupt temperature changes as well as by variations in the influent composition. Substantial differences in operation were observed between summer and winter season. In the winter, permeability was 20 to 50% lower then in the summer and generally lower fluxes were applied.