Activity of Ammonium-Oxidizing Bacteria—An Essential Parameter for Model-Based N2O Mitigation Control Strategies for Biofilms

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OriginalspracheEnglisch
Aufsatznummer2389
FachzeitschriftWater
Jahrgang15
Ausgabenummer13
PublikationsstatusVeröffentlicht - 28 Juni 2023

Abstract

The reduction in N 2O emissions is an important task in the control of wastewater treatment plants. Since local operating conditions, especially inside biofilms, are usually not known, models are an important tool in the development and implementation of control strategies. For a pilot-scale nitrifying biofilm reactor and an SBR, different operational strategies to reduce autotrophic nitrous oxide (N 2O) formation were developed and tested by applying a combination of modeling and measurement. Both approaches highlighted the relevance of addressing the actual AOB activity as a sensitive control variable. The investigated strategies, therefore, focused on decreasing the AOB-related NH 4 conversion rate, as autotrophic N 2O formation is directly linked to AOB activity. The results showed that the biofilm system was more advantageous compared with suspended sludge systems. A higher AOB content resulted in a decrease in AOB activity, leading to fewer N 2O emissions at the same reactor performance. The highest reduction in autotrophic N 2O formation (SBR: 25%; Biofilm: 27%) was obtained by maximizing the aerated time per day and minimizing the number of aeration cycles (the suppression of nitrite-oxidizing bacteria still needed to be ensured). A higher biofilm thickness or a higher sludge mass in the SBR, however, did not have a noteworthy positive effect since no additional biomass could be kept in the system in the long term due to limited substrate availability. Besides nitritation, denitrification was also identified as a relevant source of N 2O in both systems (biofilm: main source) due to the inhibition of N 2O reduction by nitrous acid (elevated nitrite concentrations in combination with pH values < 7).

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Activity of Ammonium-Oxidizing Bacteria—An Essential Parameter for Model-Based N2O Mitigation Control Strategies for Biofilms. / Freyschmidt, Arne; Beier, Maike.
in: Water, Jahrgang 15, Nr. 13, 2389, 28.06.2023.

Publikation: Beitrag in FachzeitschriftArtikelForschungPeer-Review

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@article{0814bac97a564ce98b0381bc1e00e980,
title = "Activity of Ammonium-Oxidizing Bacteria—An Essential Parameter for Model-Based N2O Mitigation Control Strategies for Biofilms",
abstract = "The reduction in N 2O emissions is an important task in the control of wastewater treatment plants. Since local operating conditions, especially inside biofilms, are usually not known, models are an important tool in the development and implementation of control strategies. For a pilot-scale nitrifying biofilm reactor and an SBR, different operational strategies to reduce autotrophic nitrous oxide (N 2O) formation were developed and tested by applying a combination of modeling and measurement. Both approaches highlighted the relevance of addressing the actual AOB activity as a sensitive control variable. The investigated strategies, therefore, focused on decreasing the AOB-related NH 4 conversion rate, as autotrophic N 2O formation is directly linked to AOB activity. The results showed that the biofilm system was more advantageous compared with suspended sludge systems. A higher AOB content resulted in a decrease in AOB activity, leading to fewer N 2O emissions at the same reactor performance. The highest reduction in autotrophic N 2O formation (SBR: 25%; Biofilm: 27%) was obtained by maximizing the aerated time per day and minimizing the number of aeration cycles (the suppression of nitrite-oxidizing bacteria still needed to be ensured). A higher biofilm thickness or a higher sludge mass in the SBR, however, did not have a noteworthy positive effect since no additional biomass could be kept in the system in the long term due to limited substrate availability. Besides nitritation, denitrification was also identified as a relevant source of N 2O in both systems (biofilm: main source) due to the inhibition of N 2O reduction by nitrous acid (elevated nitrite concentrations in combination with pH values < 7).",
keywords = "aeration strategies, biofilm, extended ASM model, greenhouse gas emissions, process control",
author = "Arne Freyschmidt and Maike Beier",
note = "This work was carried out as part of the MiNzE project ({\textquoteleft}Minimization of the CO2 footprint by adapted process development in process water treatment—testing of the MiNzE process in an immersed fixed bed{\textquoteright}, FKZ: 02WQ1482B). We thank the German Federal Ministry of Education and Research for financial support.",
year = "2023",
month = jun,
day = "28",
doi = "10.3390/w15132389",
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issn = "2073-4441",
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Download

TY - JOUR

T1 - Activity of Ammonium-Oxidizing Bacteria—An Essential Parameter for Model-Based N2O Mitigation Control Strategies for Biofilms

AU - Freyschmidt, Arne

AU - Beier, Maike

N1 - This work was carried out as part of the MiNzE project (‘Minimization of the CO2 footprint by adapted process development in process water treatment—testing of the MiNzE process in an immersed fixed bed’, FKZ: 02WQ1482B). We thank the German Federal Ministry of Education and Research for financial support.

PY - 2023/6/28

Y1 - 2023/6/28

N2 - The reduction in N 2O emissions is an important task in the control of wastewater treatment plants. Since local operating conditions, especially inside biofilms, are usually not known, models are an important tool in the development and implementation of control strategies. For a pilot-scale nitrifying biofilm reactor and an SBR, different operational strategies to reduce autotrophic nitrous oxide (N 2O) formation were developed and tested by applying a combination of modeling and measurement. Both approaches highlighted the relevance of addressing the actual AOB activity as a sensitive control variable. The investigated strategies, therefore, focused on decreasing the AOB-related NH 4 conversion rate, as autotrophic N 2O formation is directly linked to AOB activity. The results showed that the biofilm system was more advantageous compared with suspended sludge systems. A higher AOB content resulted in a decrease in AOB activity, leading to fewer N 2O emissions at the same reactor performance. The highest reduction in autotrophic N 2O formation (SBR: 25%; Biofilm: 27%) was obtained by maximizing the aerated time per day and minimizing the number of aeration cycles (the suppression of nitrite-oxidizing bacteria still needed to be ensured). A higher biofilm thickness or a higher sludge mass in the SBR, however, did not have a noteworthy positive effect since no additional biomass could be kept in the system in the long term due to limited substrate availability. Besides nitritation, denitrification was also identified as a relevant source of N 2O in both systems (biofilm: main source) due to the inhibition of N 2O reduction by nitrous acid (elevated nitrite concentrations in combination with pH values < 7).

AB - The reduction in N 2O emissions is an important task in the control of wastewater treatment plants. Since local operating conditions, especially inside biofilms, are usually not known, models are an important tool in the development and implementation of control strategies. For a pilot-scale nitrifying biofilm reactor and an SBR, different operational strategies to reduce autotrophic nitrous oxide (N 2O) formation were developed and tested by applying a combination of modeling and measurement. Both approaches highlighted the relevance of addressing the actual AOB activity as a sensitive control variable. The investigated strategies, therefore, focused on decreasing the AOB-related NH 4 conversion rate, as autotrophic N 2O formation is directly linked to AOB activity. The results showed that the biofilm system was more advantageous compared with suspended sludge systems. A higher AOB content resulted in a decrease in AOB activity, leading to fewer N 2O emissions at the same reactor performance. The highest reduction in autotrophic N 2O formation (SBR: 25%; Biofilm: 27%) was obtained by maximizing the aerated time per day and minimizing the number of aeration cycles (the suppression of nitrite-oxidizing bacteria still needed to be ensured). A higher biofilm thickness or a higher sludge mass in the SBR, however, did not have a noteworthy positive effect since no additional biomass could be kept in the system in the long term due to limited substrate availability. Besides nitritation, denitrification was also identified as a relevant source of N 2O in both systems (biofilm: main source) due to the inhibition of N 2O reduction by nitrous acid (elevated nitrite concentrations in combination with pH values < 7).

KW - aeration strategies

KW - biofilm

KW - extended ASM model

KW - greenhouse gas emissions

KW - process control

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DO - 10.3390/w15132389

M3 - Article

VL - 15

JO - Water

JF - Water

SN - 2073-4441

IS - 13

M1 - 2389

ER -