TY - JOUR

T1 - Model assisted identification of N2O mitigation strategies for full-scale reject water treatment plants

AU - Beier, M.

AU - Feldkämper, I.

AU - Freyschmidt, A.

N1 - Funding Information: The basic work was carried out in the frame of the German-Polish joint research project ReNeMo (Beier et al. 2017). This project also provides the background for the dissertation of Benjamin Vogel (Vogel 2018). The denitrification kinetic studies are part of the MiNzE project started in 2019. Both projects are financially supported by the German Federal Ministry of Education and Research. We would like to thank the ministry for the support and the opportunity to transfer the idea of the MiNzE concept into practice within the program ‘BMBF innovative, practice-oriented research for SME’. The kinetic studies were enabled by the excellent equipped DFG funded research device and will be continued in the future in further detail.

PY - 2021/7/15

Y1 - 2021/7/15

N2 - In a 3-year research project, a new approach to forecast biological N2O formation and emission at high-strength reject water treatment has been developed (ASM3/1_N2OISAH). It was calibrated by extensive batch-tests and finally evaluated by long-term measurement campaigns realized at three wastewater treatment plants (WWTPs) with different process configurations for nitrogen removal of reject water. To enable a model application with common full-scale data, the nitritation-connected supplementary processes that are responsible for N2O formation are not depicted in the model. Instead, within the new model approach the N2O formation is linked to the NH4-N oxidation rate by defining specific formation factors [N2O-Nform/NH4-Nox], depending on the concentrations of NO2 and O2 as well as the NH4 load. A comparison between the measured and the modeled N2O concentrations in the liquid and gas phase at the full-scale treatment plants prove the ability of the proposed modelling approach to represent the observed trends of N2O formation, emission and reduction using the standard parameter set of kinetics and formation factors. Thus, enabling a reliable estimation of the N2O emissions for different operational conditions. The measurements indicate that a formation of N2O by AOB cannot completely be avoided. However, a considerable reduction of the formed N2O was observed in an anoxic environment. Applying the model, operational settings and mitigation strategies can now be identified without extensive measurement campaigns. For further enhancement of the model, first results for kinetics of N2O reduction kinetics by denitrification processes were determined in laboratory-scale batch tests.

AB - In a 3-year research project, a new approach to forecast biological N2O formation and emission at high-strength reject water treatment has been developed (ASM3/1_N2OISAH). It was calibrated by extensive batch-tests and finally evaluated by long-term measurement campaigns realized at three wastewater treatment plants (WWTPs) with different process configurations for nitrogen removal of reject water. To enable a model application with common full-scale data, the nitritation-connected supplementary processes that are responsible for N2O formation are not depicted in the model. Instead, within the new model approach the N2O formation is linked to the NH4-N oxidation rate by defining specific formation factors [N2O-Nform/NH4-Nox], depending on the concentrations of NO2 and O2 as well as the NH4 load. A comparison between the measured and the modeled N2O concentrations in the liquid and gas phase at the full-scale treatment plants prove the ability of the proposed modelling approach to represent the observed trends of N2O formation, emission and reduction using the standard parameter set of kinetics and formation factors. Thus, enabling a reliable estimation of the N2O emissions for different operational conditions. The measurements indicate that a formation of N2O by AOB cannot completely be avoided. However, a considerable reduction of the formed N2O was observed in an anoxic environment. Applying the model, operational settings and mitigation strategies can now be identified without extensive measurement campaigns. For further enhancement of the model, first results for kinetics of N2O reduction kinetics by denitrification processes were determined in laboratory-scale batch tests.

KW - Asm

KW - Denitrification

KW - Greenhouse gas emission

KW - Modelling

KW - Nitrous oxide

KW - Reject water

UR - http://www.scopus.com/inward/record.url?scp=85111893022&partnerID=8YFLogxK

U2 - 10.2166/wst.2021.141

DO - 10.2166/wst.2021.141

M3 - Article

VL - 84

SP - 349

EP - 363

JO - Water Science and Technology

JF - Water Science and Technology

SN - 0273-1223

IS - 2

ER -