Nitritation and N2O Emission in a Denitrification and Nitrification Two-Sludge System Treating High Ammonium Containing Wastewater

Abstract

Abstract:The effective management of high ammonium containing wastewater is important for the sustainable development of the wastewater industry. A pre-denitrification and post-nitrification two-sludge system was proposed to treat high ammonium containing wastewater with low carbon-to-nitrogen (C/N) ratios. In the system, pre-denitrification was adopted to use organic carbon in raw wastewater efficiently for nitrogen removal, while post-nitrification was adopted to achieve nitritation. System performance and the characteristics of nitrous oxide (N2O) emission were examined. As to the influent chemical oxygen demand (COD) and ammonium nitrogen (NH4-N) concentration, both 800 mg/L, nitrogen removal was mainly through pre-denitrification, and the nitrogen removal percentage was 43.4%. In post-nitrification, nitritation was achieved with a nitrite accumulation efficiency of 97.8% and a NH4-N removal loading rate of 0.45 g/(L·d). With nitrite as the electron acceptor during denitrification, its removal rate increased, while the N2O emission factor decreased with increasing C/N ratios. Nitrification was affected significantly by the aeration rate. When the aeration rate was below 0.6 L/min, the NH4-N removal rate increased, while the N2O emission rate decreased with increasing aeration rates. However, when the aeration rate was above 0.6 L/min, it had little influence on N2O OPEN ACCESSWater 2014, 6 2979 emission. During nitrification, N2O emission factors decreased exponentially with increasing ammonium oxidation rates.

Effects of aeration and internal recycle flow on nitrous oxide emissions from a modified Ludzak–Ettinger process fed with glycerol

“…The nitrification efficiencies did not significantly differ (P>0.05) between the high and low aeration periods, although nitrification was significantly affected by the aeration rate in an SBR process ). This inconsistency likely arises from the lower influent NH 4 + -N loading in this study than in the previous study (0.007 vs 0.289 kg N/m 3 /day; see Wu et al 2014). On the other hand, neither aeration condition significantly affected the DOC and DTN removal efficiencies (P>0.05), contradicting a previous finding that the DOC and DTN removal efficiencies depend on the aeration rates in an SBR .…”

Mechanisms of nitrous oxide (N2O) formation and reduction in denitrifying biofilms

“…Eldyasti, Nakhla, and Zhu () found that the biofilm thickness can play an important role in N 2 O emissions. Research has also investigated the potential for accumulation in nitrifying and denitrifying systems, and found that high concentration in both cases can lead to higher N 2 O emissions (Kampschreur, Temmink, Kleerebezem, Jetten, & van Loosdrecht, ; Lu & Chandran, ; Wu, Zheng, & Xing, ). However, these studies involved complex systems, in which the biofilm thicknesses, microbial composition, and substrate concentrations were not well characterized.…”

Nitrous oxide from moving bed based integrated fixed film activated sludge membrane bioreactors

“…In the last years, many efforts have been devoted towards the understanding of the key mechanisms involved in N 2 O production and emission (Kampschreur et al, 2009;Quan et al, 2012;Rodriguez-Caballero and Pijuan, 2013;Stenstr€ om et al, 2014;Wu et al, 2014;Hwang et al, 2016;Mannina et al, 2016c). The reported studies demonstrated a huge variability of the N 2 O emission (from the 0.01% to 10% of the influent total nitrogen) (Yoshida et al, 2014), depending on the WWTPs operational conditions (Kampschreur et al, 2009;Law et al, 2012;Daelman et al, 2013).…”