Evaluation of hybrid processes for nitrification by comparing MBBR/AS and IFAS configurations

Abstract

An integrated fixed-film activated sludge (IFAS) pilot plant and a moving bed biofilm reactor coupled with an activated sludge process (MBBR/AS) were operated under different temperatures, carbon loadings and solids retention times (SRTs). These two types of hybrid systems were compared, focusing on the nitrification capacity and the nitrifiers population of the media and suspended biomass alongside other process performances such as carbonaceous and total nitrogen (TN) removal rates. At high temperatures and loadings rates, both processes were fully nitrifying and achieved similarly high carbonaceous removal rates. However, under these conditions, the IFAS configuration performed better in terms of TN removal. Lower temperatures and carbon loadings led to lower carbonaceous removal rates for the MBBR/AS configuration, whereas the IFAS configuration was not affected. However, the nitrification capacity of the IFAS process decreased significantly under these conditions and the MBBR/AS process was more robust in terms of nitrification. Ammonia oxidising bacteria (AOB) and nitrite oxidising bacteria (NOB) population counts accurately reflected the changes in nitrification capacity. However, significantly less NOBs than AOBs were observed, without noticeable nitrite accumulation, suggesting that the characterisation method used was not as sensitive for NOBs and/or that the NOBs had a higher activity than the AOBs.

Effect of carbon source on acclimatization of nitrifying bacteria to achieve high-rate partial nitrification of wastewater with high ammonium concentration

“…Researchers confirmed the improvement of nitrification at low temperatures in the presence of heterotrophic bacteria, because they act as a protective layer for the nitrifying bacteria. Nevertheless, in this situation, the specific activity of AOB is lesser than when only nitrifying bacteria are present (Germain et al 2007;Wu et al 2008). …”

“…The addition had a marginal effect on the nitrification rate. pH and DO were automatically kept within the range of 7.6 ± 0.3 and C3 mg L -1 for both groups of bacteria (heterotrophic and autotrophic bacteria, respectively) (Gerardi 2002;Wu et al 2008). An MLSS concentration of 2 g L -1 was maintained throughout the experiment with mixed liquor purged from the reactors, and the centrifuged biomass of effluent was returned to the reactors.…”

“…Substrate concentration is an important parameter in the nitrification process, which can control the rate of ammonium/nitrite oxidation because of its inhibitory effects (Gerardi 2002). The prevailing strategies for incomplete nitrification and depressing the activity of NOB have been mentioned previously.…”

Influence of hydraulic retention time on heterotrophic biomass in a wastewater moving bed membrane bioreactor treatment plant

“…Indeed, attached growth systems are generally considered less sensitive to toxic influents and variations in environmental conditions (Wang et al 2005). Several studies have demonstrated that, with MB, it is possible to get efficiencies in biochemical oxygen demand (BOD 5 ) greater than 90 % and greater than 85 % in chemical oxygen demand (COD) (Germain et al 2007;Davis et al 2009;Kim et al 2010).…”

Eliminación de nutrientes mediante tratamientos biopelícula : corrientes actuales y necesidades de investigación

“…Varios estudios indican que las plantas en las que se ha incluido MBBR IFAS consiguen un comportamiento general mejor que los fangos activos convencionales (Rusten et al 2003) (Germain et al 2007) (Di Trapani et al 2011). …”