The inhibitory impact of ammonia on thermally hydrolyzed sludge fed anaerobic digestion
© 2021 Water Environment Federation.
| Veröffentlicht in: | Water environment research : a research publication of the Water Environment Federation. - 1998. - 93(2021), 8 vom: 15. Aug., Seite 1263-1275 |
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| Weitere Verfasser: | , , , , , , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2021
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| Zugriff auf das übergeordnete Werk: | Water environment research : a research publication of the Water Environment Federation |
| Schlagworte: | Journal Article AD NH3 TAN THP biosolids free ammonia inhibition kinetics Sewage Ammonia mehr... |
| Zusammenfassung: | © 2021 Water Environment Federation. This study evaluated the impact of ammonia on mesophilic anaerobic digestion (AD) with thermal hydrolysis pretreatment (THP) treating a mixture of primary sludge and waste activated sludge and operated under constant organic loading rate of 9 kg COD/m3 /d. Free ammonia concentrations in the digesters were varied between 37 and 966 mg NH3 -N/L, while maintaining all other operational conditions constant. A decrease in volatile solids reduction from 54 ± 5% (at <554 mg NH3 -N/L) to 35 ± 6% at the maximum free ammonia concentration of 966 mg NH3 -N/L was observed at steady-state conditions. No impact of free ammonia on final dewaterability was detected. Free ammonia thus mostly limited methanogenesis. A free ammonia Monod inhibition constant of 847 ± 222 mg NH3 -N/L for methanogens was estimated based on the digester steady-state methane rates dynamics. This study showed that current THP AD digesters (typically 110-260 mg NH3 -N/L) operate under 12%-18% ammonia inhibition for methanogenesis. Operation under SRT of 15 days, about 2 times more than needed to retain methanogens, can compensate for lower methanogens rates and avoid performance impacts. The later shows a good potential to operate under higher free and total ammonia concentration without jeopardizing performance. PRACTITIONER POINTS: Only from a free ammonia concentration above 554 mg NH3 -N/L, decreased volatile solids reduction and biogas yield were observed. A volatile solids reduction of 35 ± 6% at maximum free ammonia concentration of 966 mg NH3 -N/L was still achieved. A Monod inhibition constant for methanogens of 847 ± 222 mg NH3 -N/L was estimated. It was estimated that current THP AD systems (110-260 mg NH3 -N/L) operate under 12%-18% NH3 inhibition for methanogenesis |
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| Beschreibung: | Date Completed 27.08.2021 Date Revised 27.08.2021 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1554-7531 |
| DOI: | 10.1002/wer.1509 |