Comparison of Nitrification Rates in Conventional and Membrane‐Assisted Biological Nutrient Removal Processes

Abstract

A membrane-assisted and a conventional activated sludge system, both operated in an enhanced biological phosphorus removal (EBPR) mode and under identical operating conditions, were studied to investigate the effect of the membrane solids-liquid separation on nitrification activity. Both the membrane EBPR (MEBPR) and conventional EBPR (CEBPR) processes achieved stable and complete removal of ammoniumnitrogen from the influent wastewater. However, when the intrinsic nitrification activity was assessed in offline batch tests, the CEBPR mixed liquor exhibited 15 to 75% greater nitrification potential than the MEBPR counterpart. These results were further validated by monitoring nitrification rates of conventional mixed liquor as it evolved toward a membrane mixed liquor. It was also demonstrated that the larger aerobic mass fraction of the MEBPR system could not be the only factor influencing the reduced intrinsic nitrification rate. The present study strongly suggests that the presence of a membrane solids-liquid separation per se may be sufficient to alter the nitrification kinetics of an EBPR mixed liquor and that this possibility should be considered in arriving at an appropriate process design. Water Environ. Res., 80, 497 (2008).

Tuning Biological Nutrient Removal Plants

“…Fourthly, MBR processes are reported to have somewhat lower nitrification rates than conventional processes (Monti & Hall, 2008), and to be more prone to foaming (Monti et al, 2006). Prevention of effluent solids discharge by replacement of clarifiers with membranes leads to shifts in the composition of the biomass (Hall et al, 2010).…”

Steady state modeling of autotrophic membrane bioreactor – a new approach to quantify biomass

“…The technologies used for identifying and quantifying bacteria, such as the polymerase chain reaction and scanning electron microscopy AGJSR (Zhang et al, 2017;Islam et al, 2017), were very sophisticated and were not available to some researchers. Moreover, modeling tools still need to be expanded to identify active bacterial populations and measure their own reactions (Monti and Hall, 2008). Therefore, this work focuses on the development of a new tool for quantifying the active biomass and characterizing the specific activity of autotrophic populations in a wastewater treatment reactor.…”