Contribution of nitrous oxide emissions from wastewater treatment to carbon accounting

2012 ◽  
Vol 3 (2) ◽  
pp. 95-109 ◽  
Author(s):  
P. Winter ◽  
P. Pearce ◽  
K. Colquhoun

This paper describes research that investigated the contribution of nitrous oxide (N2O) emissions from wastewater treatment to the greenhouse gas emissions of a wastewater treatment plant (WWTP). The research provided several months of robust data from a large-scale WWTP serving a population equivalent of 284,000. N2O emissions were monitored online at the ventilation system of a covered activated sludge (AS) plant, therefore capturing the complete off-gas stream. This methodology eliminated errors incurred through sampling of small percentages of emission areas and allowed representative continuous measurements. Nitrogen load and dissolved oxygen (DO) were also monitored. To address seasonal variation, data were recorded in two extensive phases. In addition, three separate 24-hour surveys were conducted. Emissions of CO2, CH4 and N2O associated with treatment were calculated using the UK Water Industry Research carbon accounting workbook. This study measured N2O emissions from the AS process (nitrification and denitrification) equivalent to 17.5% of the annual GHG emissions (tonnes CO2e) from processes at the WWTP. The emissions were within the range of published N2O emissions. The diurnal profiles confirmed literature findings of a trend of increased N2O emissions when the DO decreased. The DO in the high rate zone of the aeration lanes should be kept above 1 mg l−1 to avoid favourable conditions for N2O emissions during nitrification.

2020 ◽  
Vol 82 (6) ◽  
pp. 1025-1030
Author(s):  
Maxence Plouviez ◽  
Benoit Guieysse

Abstract Microalgae can synthesise the ozone depleting pollutant and greenhouse gas nitrous oxide (N2O). Consequently, significant N2O emissions have been recorded during real wastewater treatment in high rate algal ponds (HRAPs). While data scarcity and variability prevent meaningful assessment, the magnitude reported (0.13–0.57% of the influent nitrogen load) is within the range reported by the Intergovernmental Panel on Climate Change (IPCC) for direct N2O emissions during centralised aerobic wastewater treatment (0.016–4.5% of the influent nitrogen load). Critically, the ability of microalgae to synthesise N2O challenges the IPCC's broad view that bacterial denitrification and nitrification are the only major cause of N2O emissions from wastewater plants and aquatic environments receiving nitrogen from wastewater effluents. Significant N2O emissions have indeed been repeatedly detected from eutrophic water bodies and wastewater discharge contributes to eutrophication via the release of nitrogen and phosphorus. Considering the complex interplays between nitrogen and phosphorus supply, microalgal growth, and microalgal N2O synthesis, further research must urgently seek to better quantify N2O emissions from microalgae-based wastewater systems and eutrophic ecosystems receiving wastewater. This future research will ultimately improve the prediction of N2O emissions from wastewater treatment in national inventories and may therefore affect the prioritisation of mitigation strategies.


Engevista ◽  
2015 ◽  
Vol 17 (3) ◽  
pp. 375 ◽  
Author(s):  
Renato Pereira Ribeiro ◽  
Jaime Lopes da Mota Oliveira ◽  
Débora Cynamon Kligerman ◽  
Renata Barbosa Alvim ◽  
Samara Almeida Andrade ◽  
...  

Nitrous oxide emissions were determined in three campaigns in the aeration tank of a full scale conventional activated sludge wastewater treatment plant. During these experiments, the carbonaceous organic matter (BOD and COD) removal was high and rather constant (97-98% and 93-96%). The results indicate that the concentration of total nitrogen in the influent wastewater, especially NH4+, and the aeration flow rate are key controlling factor of N2O emissions from the aeration tank. Nitrification was the major source of N2O, suggested by the behavior of DO concentrations, NO3-/NH4+ ratio and pH values along the six interlinked zones of the aeration tank. Excessive air flow intensified N2O transfer from the liquor to the atmosphere by air stripping.


Química Nova ◽  
2013 ◽  
Vol 36 (1) ◽  
pp. 16-20 ◽  
Author(s):  
William Z. de Mello ◽  
Renato P. Ribeiro ◽  
Ariane C. Brotto ◽  
Débora C. Kligerman ◽  
Andrezza de S. Piccoli ◽  
...  

2009 ◽  
Vol 2009 (10) ◽  
pp. 5347-5361 ◽  
Author(s):  
Joseph A. Kozak ◽  
Catherine O'Connor ◽  
Thomas Granato ◽  
Louis Kollias ◽  
Francesco Belluci ◽  
...  

2021 ◽  
Author(s):  
Hanxiong Song ◽  
Changhui Peng ◽  
Kerou Zhang ◽  
Qiuan Zhu

Abstract. Nitrous oxide (N2O) emissions from croplands are one of the most important greenhouse gas sources, and it is difficult to simulate on a large scale. In order to simulate N2O emissions from global croplands, a new version of the process-based TRIPLEX-GHG model was developed by coupling the major agricultural activities. The coefficient of the NO3− consumption rate for denitrification (COEdNO3) was found to be the most sensitive parameter based on sensitivity analysis, and it was calibrated using field data from 39 observation sites across major croplands globally. The model performed well when simulating the magnitude of the daily N2O emissions and was able to capture the temporal patterns of the N2O emissions. The COEdNO3 ranged from 0.01 to 0.05, and the continental mean of the parameter was used for the model validation. The validation results indicate that the means of the measured daily N2O fluxes during the experiment periods are highly correlated with the modeled results (R2 = 0.87). Consequently, our model simulation results demonstrate that the new version of the TRIPLEX-GHG model can reliably simulate N2O emissions from various croplands at the global scale.


Author(s):  
Anna Jędrejek

The purpose of this study was to estimate nitrogen oxide emissions from soils used for agricultural purposes by voivodships. Compared N2O emissions were estimated according to the recommended IPCC (tier 1) method with simulated emissions using the DNDC (tier 3) model. Analyses were done for crop rotation (winter rape, winter wheat, winter wheat, winter triticale) in four cropping systems. Moreover, simulated N2O emissions from winter rape and winter triticale cultivation showed lower emissions and constituted 1475% and 13-76% of IPCC estimated emissions, respectively. The use of the model also enabled the determination of factors, which have an impact on nitrous oxide emissions and define its regional differentiation. The analysis showed that with increasing initial soil organic content, emissions of N2O rise and decrease with increasing precipitation or carbon sequestration. Considering the requirements for reduction GHG emissions, improving the methodology used in estimating nitrous oxide emissions is of significant practical value.


Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1013 ◽  
Author(s):  
Takahiro Yamashita ◽  
Makoto Shiraishi ◽  
Hiroshi Yokoyama ◽  
Akifumi Ogino ◽  
Ryoko Yamamoto-Ikemoto ◽  
...  

Nitrous oxide (N2O) is a potent greenhouse gas that is emitted from wastewater treatment plants. To reduce emissions of N2O from swine wastewater treatment plants, we constructed an experimental aerobic bioreactor packed with carbon fibres (ca. 1 m3 bioreactor) as an alternative to conventional activated sludge treatment. The N2O emission factor for the aerobic bioreactor packed with carbon fibres (CF) was 0.002 g N2O-N/g TN-load and the value for the typical activated sludge (AS) reactor was 0.013 g N2O-N/g TN-load. The CF treatment method achieved more than 80% reduction of N2O emissions, compared with the AS treatment method. The experimental introduction of a CF carrier into an actual wastewater treatment plant also resulted in a large reduction in N2O generation. Specifically, the N2O emission factors decreased from 0.040 to 0.005 g N2O-N/g TN-load following application of the carrier. This shows that it is possible to reduce N2O generation by more than 80% by using a CF carrier during the operation of an actual wastewater treatment plant. Some bacteria from the phylum Chloroflexi, which are capable of reducing N2O emissions, were detected at a higher frequency in the biofilm on the CF carrier than in the biofilm formed on the AS reactor.


2019 ◽  
Vol 44 ◽  
pp. 101670 ◽  
Author(s):  
Maxence Plouviez ◽  
Paul Chambonnière ◽  
Andy Shilton ◽  
Michael A. Packer ◽  
Benoit Guieysse

Author(s):  
A. Kuokkanen ◽  
K. Blomberg ◽  
A. Mikola ◽  
M. Heinonen

Abstract Nitrous oxide emissions can contribute significantly to the carbon footprint of municipal wastewater treatment plants even though emissions from conventional nitrogen removal processes are assumed to be moderate. An increased risk for high emissions can occur in connection with process disturbances and nitrite (NO2−) accumulation. This work describes the findings at a large municipal wastewater treatment plant where the levels of NO2− in the activated sludge process effluent were spontaneously and strongly increased on several activated sludge lines which was suspected to be due to shortcut nitrogen removal that stabilized for several months. The high NO2− levels were linked to a dramatic increase in nitrous oxide (N2O) emissions. As much as over 20% of the daily influent nitrogen load was emitted as N2O. These observations indicate that highly increased NO2− levels can occur in conventional activated sludge processes and result in high nitrous oxide emissions. They also raise questions concerning the risk of increased greenhouse gas (GHG) emissions of the nitritation-denitritation processes – although the uncontrolled nature of the event described here must be taken into consideration – and underline the importance of continuous monitoring and control of N2O emissions.


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