Effects of Increasing Nitrogen Content on Process Stability and Reactor Performance in Anaerobic Digestion
The aim of this study was to analyse the effect of different nitrogen increase rates in feedstock on the process stability and conversion efficiency in anaerobic digestion (AD). The research was conducted in continuously stirred tank reactors (CSTR), initially filled with two different inocula: inoc...
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2020-03-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/13/5/1139 |
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| author | Ievgeniia Morozova Nadiia Nikulina Hans Oechsner Johannes Krümpel Andreas Lemmer |
| author_facet | Ievgeniia Morozova Nadiia Nikulina Hans Oechsner Johannes Krümpel Andreas Lemmer |
| author_sort | Ievgeniia Morozova |
| collection | DOAJ |
| description | The aim of this study was to analyse the effect of different nitrogen increase rates in feedstock on the process stability and conversion efficiency in anaerobic digestion (AD). The research was conducted in continuously stirred tank reactors (CSTR), initially filled with two different inocula: inocula #1 with low and #2 with high nitrogen (N) concentrations. Three N feeding regimes were investigated: the “0-increase” feeding regime with a constant N amount in feeding and the regimes “0.25-increase” and “0.5-increase” where the N concentrations in feedstock were raised by 0.25 and 0.5 g·kg<sup>−1</sup>, respectively, related to fresh matter (FM) every second week. The N concentration inside the reactors increased according to the feeding regimes. The levels of inhibition (Inhibition) in specific methane yields (<i>SMY</i>), related to the conversion efficiency of the substrates, were quantified. At the N concentration in digestate of 10.82 ± 0.52 g·kg<sup>−1</sup> FM measured in the reactors with inoculum #2 and “0.5-increase” feeding regime, the level of inhibition was equal to 38.99% ± 14.99%. The results show that high nitrogen increase rates in feeding regime are negatively related to the efficiency of the AD process, even if low volatile fatty acid (VFA) concentrations indicate a stable process. |
| first_indexed | 2024-04-11T12:33:00Z |
| format | Article |
| id | doaj.art-12beca2bc4c847e5aa2019e5f7c43ecb |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-11T12:33:00Z |
| publishDate | 2020-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-12beca2bc4c847e5aa2019e5f7c43ecb2022-12-22T04:23:42ZengMDPI AGEnergies1996-10732020-03-01135113910.3390/en13051139en13051139Effects of Increasing Nitrogen Content on Process Stability and Reactor Performance in Anaerobic DigestionIevgeniia Morozova0Nadiia Nikulina1Hans Oechsner2Johannes Krümpel3Andreas Lemmer4State Institute of Agricultural Engineering and Bioenergy, University of Hohenheim, 70599 Stuttgart, GermanyState Institute of Agricultural Engineering and Bioenergy, University of Hohenheim, 70599 Stuttgart, GermanyState Institute of Agricultural Engineering and Bioenergy, University of Hohenheim, 70599 Stuttgart, GermanyState Institute of Agricultural Engineering and Bioenergy, University of Hohenheim, 70599 Stuttgart, GermanyState Institute of Agricultural Engineering and Bioenergy, University of Hohenheim, 70599 Stuttgart, GermanyThe aim of this study was to analyse the effect of different nitrogen increase rates in feedstock on the process stability and conversion efficiency in anaerobic digestion (AD). The research was conducted in continuously stirred tank reactors (CSTR), initially filled with two different inocula: inocula #1 with low and #2 with high nitrogen (N) concentrations. Three N feeding regimes were investigated: the “0-increase” feeding regime with a constant N amount in feeding and the regimes “0.25-increase” and “0.5-increase” where the N concentrations in feedstock were raised by 0.25 and 0.5 g·kg<sup>−1</sup>, respectively, related to fresh matter (FM) every second week. The N concentration inside the reactors increased according to the feeding regimes. The levels of inhibition (Inhibition) in specific methane yields (<i>SMY</i>), related to the conversion efficiency of the substrates, were quantified. At the N concentration in digestate of 10.82 ± 0.52 g·kg<sup>−1</sup> FM measured in the reactors with inoculum #2 and “0.5-increase” feeding regime, the level of inhibition was equal to 38.99% ± 14.99%. The results show that high nitrogen increase rates in feeding regime are negatively related to the efficiency of the AD process, even if low volatile fatty acid (VFA) concentrations indicate a stable process.https://www.mdpi.com/1996-1073/13/5/1139biogasmethaneammoniainhibitionacclimatizationtrace elements |
| spellingShingle | Ievgeniia Morozova Nadiia Nikulina Hans Oechsner Johannes Krümpel Andreas Lemmer Effects of Increasing Nitrogen Content on Process Stability and Reactor Performance in Anaerobic Digestion Energies biogas methane ammonia inhibition acclimatization trace elements |
| title | Effects of Increasing Nitrogen Content on Process Stability and Reactor Performance in Anaerobic Digestion |
| title_full | Effects of Increasing Nitrogen Content on Process Stability and Reactor Performance in Anaerobic Digestion |
| title_fullStr | Effects of Increasing Nitrogen Content on Process Stability and Reactor Performance in Anaerobic Digestion |
| title_full_unstemmed | Effects of Increasing Nitrogen Content on Process Stability and Reactor Performance in Anaerobic Digestion |
| title_short | Effects of Increasing Nitrogen Content on Process Stability and Reactor Performance in Anaerobic Digestion |
| title_sort | effects of increasing nitrogen content on process stability and reactor performance in anaerobic digestion |
| topic | biogas methane ammonia inhibition acclimatization trace elements |
| url | https://www.mdpi.com/1996-1073/13/5/1139 |
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