The effect of temperature shifts on N2O and NO emissions from a partial nitritation reactor treating reject wastewater

Abstract

Temperature has a known effect on ammonia oxidizing bacteria (AOB) activities, reducing its ammonia oxidizing rate (AOR) when temperature is lowered. However, little is known concerning its effect on NO and NO emissions which are produced during ammonia oxidation having a greenhouse effect. To study this, an AOB enriched partial nitrification sequencing batch reactor (PN-SBR) was operated within a two step-wise feed under 5 different temperatures (30-25-20-15-10 °C). A decrease on the specific AOR (sAOR) was detected when decreasing the temperature. NO emissions were also affected by the temperature but only the ones produced during the first aeration of the cycle, when AOBs shifted from a period of low activity to a period of high activity. NO emission factors (%) detected during the second aerobic phase were similar among all temperatures tested and lower than the emissions detected during the first aerated phase. The average NO emission factor was in the range of 0.15-0.70% NO-N/NH-N oxidized in the first aeration phase and 0.14-0.15% NO-N/NH-N-oxidized in the second aeration phase at 10 to 30 °C, respectively. On the other hand, NO emissions were very similar under all temperatures resulting in 0.03-0.06% of NH-N oxidized.

Ammonium load determines the performance of a continuous nitritation process and the related microbial communities even under excesses of O2 supply

“…The bioreactor was inoculated with 10% (volume basis) of secondary activated sludge from a municipal wastewater treatment plant (WWTP) (Querétaro, México). The wastewater used throughout all of the experimentation was a synthetic medium adapted from Bao et al 20 . with the following composition (g m −3 ): NaHCO 3 500; KH 2 PO 4 64; K 2 HPO 4 64; along with 2 mL L −1 of the following trace element solution: EDTA 1250; ZnSO 4 ·H 2 O 550; CoCl 2 ·6H 2 O 400; MnCl·4H 2 O 1275; CuSO 4 ·5H 2 O 400; NaMoO 4 ·2H 2 O 50; CaCl·2H 2 O 1375; FeCl 3 ·6H 2 O 1250; MgSO 4 ·7H 2 O 44 000.…”

Nitrous oxide and methane emissions from a plug-flow full-scale bioreactor and assessment of its carbon footprint

“…Some studies have reported a link between some of the external disturbances to which a WWTP is subjected (low carbon-to-nitrogen ratio in the influent, flow rate, incoming wastewater temperature, mixed liquor sludge retention time, etc.) and the N 2 O emissions detected (Mannina et al, 2017(Mannina et al, , 2018a(Mannina et al, , 2018bSpinelli et al, 2018;Vasilaki et al, 2018). To determine if any of these parameters had an effect on the emissions detected in this study, a statistical analysis using Pearson's correlation coefficients was conducted between some measured variables and the total N 2 O and CH 4 emissions ( However, methane emissions were similar throughout the monitoring period and did not present a clear daily pattern (Figure 5 and Table 3).…”

“…50% when the temperature decreases to lower than 20 ºC (Weon et al, 2004;Bao et al, 2018). In addition, Law et al (2012b)…”

Perspective for Emission and Control of Nitrous Gas in Biological Wastewater Treatment

“…Temperature can affect N2O production by affecting the metabolic activities of functional microbes. Studies from Bao et al (2018) found that as the temperature increased from 10 to 30 °C, the average N2O emission factor decreased in the range of 0.15% ~ 0.70% N2O-N/NH4 + -N oxidized in the first aeration phase and 0.14% ~ 0.15% N2O-N/NH4 + -N-oxidized in the second aeration phase. With the increase of temperature, an aerobic environment is more likely to form within the granular sludge.…”