Effects of Hydraulic and Organic Loading Shocks on Sludge Characteristics and Its Effects on Membrane Bioreactor Performance

Occasional peak flow to the membrane bioreactor (MBR) is one of the most important factors affecting the operation and performance of the MBR system. A typical municipal MBR plant experiences peak flow conditions, which may be caused by wet weather, industrial discharge, seasonal weather changes or human activities, etc. Peak flow conditions increase the hydraulic or/and organic loading to the MBR plant. The increased hydraulic loading may result in membrane fouling or temporary process failure, if the membrane system is not designed properly. In addition, when the peak flows are associated with increased organic loading (higher F/M), this could change the mixed liquor properties and affect the membrane operation. This research focused on the effect of hydraulic and organic loading on the mixed liquor properties and MBR operation. The process parameters, including D.O, MLSS, time to filter (TTF), colloidal COD, soluble microbial products (SMP) and bound extracellular polymeric substances (EPS) under different peak conditions, has been investigated. These results improve our understanding of the filtration behavior of biomass in the MBR systems under the peak loading conditions and are useful for designing operating strategies to manage the peak flow and loading conditions.