A method to estimate the direct nitrous oxide emissions of municipal wastewater treatment plants based on the degree of nitrogen removal

Valkova, T.; Parravicini, Vanessa; Saracevic, Ernis; Tauber, Joseph; Svardal, K.; Krampe, Jörg

doi:10.1016/j.jenvman.2020.111563

Cited by 50 publications

(28 citation statements)

References 31 publications

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“…We believe that simpler, less labor-intensive measurement strategies need to be proposed. A recent study found a negative linear correlation between the N 2 O EFs and the total nitrogen removal performance of the WWTP . The linear model indicates potential opportunities for estimating N 2 O emissions with plant performance data.…”

Section: Challenges and Opportunities For N2o Mitigation At Wwtpsmentioning

confidence: 82%

“…A recent study found a negative linear correlation between the N 2 O EFs and the total nitrogen removal performance of the WWTP. 100 The linear model indicates potential opportunities for estimating N 2 O emissions with plant performance data. In addition, Galfalk and Bastviken 101 proposed a novel remote sensing approach for CH 4 and N 2 O fluxes measurement from a waste incineration plant.…”

Section: Challenges and Opportunities For N 2 Omentioning

confidence: 99%

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Insights into Nitrous Oxide Mitigation Strategies in Wastewater Treatment and Challenges for Wider Implementation

Duan

Zhao

Koch

et al. 2021

Environ. Sci. Technol.

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Nitrous oxide (N 2 O) emissions account for the majority of the carbon footprint of wastewater treatment plants (WWTPs). Many N 2 O mitigation strategies have since been developed while a holistic view is still missing. This article reviews the state-of-the-art of N 2 O mitigation studies in wastewater treatment. Through analyzing existing studies, this article presents the essential knowledge to guide N 2 O mitigations, and the logics behind mitigation strategies. In practice, mitigations are mainly carried out by aeration control, feed scheme optimization, and process optimization. Despite increasingly more studies, real implementation remains rare, which is a combined result of unclear climate change policies/incentives, as well as technical challenges. Five critical technical challenges, as well as opportunities, of N 2 O mitigations were identified. It is proposed that (i) quantification methods for overall N 2 O emissions and pathway contributions need improvement; (ii) a reliable while straightforward mathematical model is required to quantify benefits and compare mitigation strategies; (iii) tailored risk assessment needs to be conducted for WWTPs, in which more longterm full-scale trials of N 2 O mitigation are urgently needed to enable robust assessments of the resulting operational costs and impact on nutrient removal performance; (iv) current mitigation strategies focus on centralized WWTPs, more investigations are warranted for decentralised systems, especially decentralized activated sludge WWTPs; and (v) N 2 O may be mitigated by adopting novel strategies promoting N 2 O reduction denitrification or microorganisms that emit less N 2 O. Overall, we conclude N 2 O mitigation research is reaching a maturity while challenges still exist for a wider implementation, especially in relation to the reliability of N 2 O mitigation strategies and potential risks to nutrient removal performances of WWTPs.

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Section: Challenges and Opportunities For N2o Mitigation At Wwtpsmentioning

confidence: 82%

Section: Challenges and Opportunities For N 2 Omentioning

confidence: 99%

Insights into Nitrous Oxide Mitigation Strategies in Wastewater Treatment and Challenges for Wider Implementation

Duan

Zhao

Koch

et al. 2021

Environ. Sci. Technol.

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“…One of the biggest issues of the current GHG accounting methodologies is that they provide a fixed emission factor (EF) for water utilities to report their N 2 O and CH 4 emissions. In contrast, the actual N 2 O emission factor measured from different WWTPs can range from below one tenth of to five times greater than the IPCC fixed generic EF and vary between 0.001% and 12% of the incoming total nitrogen (TN) load (Valkova et al, 2021). Selecting one EF within this extremely wide range for all WWTPs, as the existing protocols do, is just not scientifically sound.…”

Section: Reporting Guidelinesmentioning

confidence: 99%

“…de Haas and Ye (2021) reported the measured average N 2 O emissions and average TN removal data from 8 WWTPs in Australia collected by the University of Queensland (UQ) and compared results with the 10 WWTPs in Europe as reported by Valkova et al (2021), and then compared the results of both studies with emission factors applied in the IPCC (2019) and the Australia National Greenhouse and Energy Reporting (NGER) (2020) protocols (shown in Figure 11.1). These datasets represent a total of 20 measurement campaigns in the period 2012-2018, including seasonal repetition.…”

Section: Reporting Guidelinesmentioning

confidence: 99%

Quantification and Modelling of Fugitive Greenhouse Gas Emissions from Urban Water Systems

2022

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With increased commitment from the international community to reduce greenhouse gas (GHG) emissions from all sectors in accordance with the Paris Agreement, the water sector has never felt the pressure it is now under to transition to a low-carbon water management model. This requires reducing GHG emissions from grid-energy consumption (Scope 2 emissions), which is straightforward; however, it also requires reducing Scope 1 emissions, which include nitrous oxide and methane emissions, predominantly from wastewater handling and treatment. The pathways and factors leading to biological nitrous oxide and methane formation and emissions from wastewater are highly complex and site-specific. Good emission factors for estimating the Scope 1 emissions are lacking, water utilities have little experience in directly measuring these emissions, and the mathematical modelling of these emissions is challenging. Therefore, this book aims to help the water sector address the Scope 1 emissions by breaking down their pathways and influencing factors, and providing guidance on both the use of emission factors, and performing direct measurements of nitrous oxide and methane emissions from sewers and wastewater treatment plants. The book also dives into the mathematical modelling for predicting these emissions and provides guidance on the use of different mathematical models based upon your conditions, as well as an introduction to alternative modelling methods, including metabolic, data-driven, and AI methods. Finally, the book includes guidance on using the modelling tools for assessing different operating strategies and identifying promising mitigation actions. A must-have book for anyone needing to understand, account for, and reduce water utility Scope 1 emissions. ISBN: 9781789060454 (Paperback) ISBN: 9781789060461 (eBook) ISBN: 9781789060478 (ePub)

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“…Environmental factors such as DO concentration, nitrite accumulation, C/N ratio and sudden changes in process conditions can affect N 2 O emissions (Guo et al 2018). Nevertheless, it is probable that N 2 O production depends primarily on the activity of the nitrifying bacteria and is triggered by high ammonia concentration (Valkova et al 2021). In the MABR, N 2 O is produced closer to the biofilm-membrane interface, i.e., where the oxygen availability is higher, and it is captured in the external layers, furthest from the biofilm-membrane interface (Kinh et al 2017).…”

Section: Graphical Abstract Introductionmentioning

confidence: 99%

Startup and initial operation of an MLE-MABR treating municipal wastewater

Silveira

Cadee

Bagg

2022

Water Science and Technology

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A 630 m3/d pilot plant was installed at Subiaco WRRF to determine design and operational parameters of a hybrid Modified Ludzack-Ettinger – Membrane Aerated Biofilm Reactor (MLE-MABR) configuration. Two commercial ZeeLung MABR cassettes were installed in series in the anoxic zone and the pilot was fed with primary effluent (averaging COD 601 mg/L, TKN 68.5 mg/L and 17–29 °C). A nitrifying biofilm was developed within 3 weeks and the nitrous oxide (N2O) gas emissions from the MABR exhaust gas proved to be a reliable parameter to assess biofilm development. Both MABRs achieved the average nitrification rate (NR) of 3.7 gNH4-N/m2.d when air flow was 8.6 and 11.2 Nm3/h to MABR1 and MABR2 respectively, which reached a maximum oxygen transfer rate of 17.4 gO2/m2.d. Biofilm thickness was controlled via air scouring and intermittent coarse bubble mixing (90 s on/90 s off). This paper discusses the startup strategy, minimum requirements for process monitoring, impact of different air flow conditions, ORP and mixing patterns on performance efficiency over a 22-week period.

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A method to estimate the direct nitrous oxide emissions of municipal wastewater treatment plants based on the degree of nitrogen removal

Cited by 50 publications

References 31 publications

Insights into Nitrous Oxide Mitigation Strategies in Wastewater Treatment and Challenges for Wider Implementation

Insights into Nitrous Oxide Mitigation Strategies in Wastewater Treatment and Challenges for Wider Implementation

Quantification and Modelling of Fugitive Greenhouse Gas Emissions from Urban Water Systems

Startup and initial operation of an MLE-MABR treating municipal wastewater

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