The influence of combined low-strength ultrasonics and micro-aerobic pretreatment process on methane generation and sludge digestion: Lipase enzyme, microbial activation, and energy yield.
Anaerobic digestion
Enzyme activation
Micro-aerobic
Pre-treatment
Ultrasonic
Journal
Ultrasonics sonochemistry
ISSN: 1873-2828
Titre abrégé: Ultrason Sonochem
Pays: Netherlands
ID NLM: 9433356
Informations de publication
Date de publication:
May 2021
May 2021
Historique:
received:
21
11
2020
revised:
09
03
2021
accepted:
14
03
2021
pubmed:
3
4
2021
medline:
11
8
2021
entrez:
2
4
2021
Statut:
ppublish
Résumé
Low-frequency ultrasonics is a potential technology to reduce the hydrolysis phase period in anaerobic digestion process. In this study, theinfluence of combined low frequency ultrasonics and micro-aerobic (MA) pretreatment on sewage sludge solubilization, enzyme activity and anaerobic digestion were assessed. Initially, the effect of ultrasonic density (0.012, 0.014, 0.016, 0.018, 0.1, 0.12 and 0.14 W/mL) and irradiation time (1, 3, 5, 8, 9, 10 and 12 min) of 20 kHz frequency waves were investigated. Accordingly, the effect of micro-aerobic pretreatment (Air flow rate (AFR) = 0.1, 0.2, 0.3 and 0.5 VVM) within 20, 30, 40.48 and 60 h were examined. In addition, the effect of combined pretreatment on COD solubilization, lipase enzyme activation, ATP, percentage of live bacteria and methane gas production during the anaerobic process were examined. The results showed that the highest lipase activity (14.9 Umol/mL) was obtained under the effect of ultrasonic density of 0.1 W/ml within 9 min. The highest solubilization (65%) was observed under optimal micro-aerobic conditions: AFR = 0.2 (VVM) and micro-aerobic time: 40 h. Combined ultrasonic and micro-aerobic (US + MA) pretreatment increases the solubilization (70%), microbial activity (2080%) and lipase enzymatic activity (129%) compared to individual pretreatment. The Biogas production during anaerobic digestion pretreated with combined methods increased by 193% compared to the control, while the elevated values of biogas production in reactors pretreated by ultrasonic and micro-aerobic pretreatment alone were observed to be 101% and 165%, respectively. The net energy in reactor with the combined pre-treatment methods was calculated to be 1.26 kWh, while this value for control, pretreated ultrasonic and micro-aerobic reactors were obtained to be 0.56, 0.67 and 1.2 kWh, respectively.
Identifiants
pubmed: 33799109
pii: S1350-4177(21)00073-0
doi: 10.1016/j.ultsonch.2021.105531
pmc: PMC8044681
pii:
doi:
Substances chimiques
Sewage
0
Lipase
EC 3.1.1.3
Methane
OP0UW79H66
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
105531Informations de copyright
Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.