Effects of Hydrothermal Pretreatment and Hydrochar Addition on the Performance of Pig Carcass Anaerobic Digestion
Proper disposal and utilization of dead pig carcasses are problems of public concern. The combination of hydrothermal pretreatment (HTP) and anaerobic digestion is a promising method to treat these wastes, provided that digestion inhibition is reduced. For this reason, the aim of this work was to in...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2021-04-01
|
| Series: | Frontiers in Microbiology |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fmicb.2021.622235/full |
| _version_ | 1818456568434262016 |
|---|---|
| author | Jie Xu Jie Xu Hongjian Lin Kuichuan Sheng |
| author_facet | Jie Xu Jie Xu Hongjian Lin Kuichuan Sheng |
| author_sort | Jie Xu |
| collection | DOAJ |
| description | Proper disposal and utilization of dead pig carcasses are problems of public concern. The combination of hydrothermal pretreatment (HTP) and anaerobic digestion is a promising method to treat these wastes, provided that digestion inhibition is reduced. For this reason, the aim of this work was to investigate the optimal HTP temperature (140–180°C) for biogas production during anaerobic digestion of dead pigs in batch systems. In addition, the effects of hydrochar addition (6 g/L) on anaerobic digestion of pork products after HTP in continuous stirred tank reactors (CSTR) were determined. According to the results, 90% of lipids and 10% of proteins present in the pork were decomposed by HTP. In addition, the highest chemical oxygen demand (COD) concentration in liquid products (LP) reached 192.6 g/L, and it was obtained after 170°C HTP. The biogas potential from the solid residue (SR) and LP was up to 478 mL/g-VS and 398 mL/g-COD, respectively. A temperature of 170°C was suitable for pork HTP, which promoted the practical biogas yield because of the synergistic effect between proteins and lipids. Ammonia inhibition was reduced by the addition of hydrochar to the CSTR during co-digestion of SR and LP, maximum ammonia concentration tolerated by methanogens increased from 2.68 to 3.38 g/L. This improved total biogas yield and degradation rate of substrates, reaching values of 28.62 and 36.06%, respectively. The acetate content in volatile fatty acids (VFA) may be used as an index that reflects the degree of methanogenesis of the system. The results of the present work may also provide guidance for the digestion of feedstock with high protein and lipid content. |
| first_indexed | 2024-12-14T22:28:44Z |
| format | Article |
| id | doaj.art-eedb4fb2d847457d835bc3ff29f85733 |
| institution | Directory Open Access Journal |
| issn | 1664-302X |
| language | English |
| last_indexed | 2024-12-14T22:28:44Z |
| publishDate | 2021-04-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Microbiology |
| spelling | doaj.art-eedb4fb2d847457d835bc3ff29f857332022-12-21T22:45:18ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2021-04-011210.3389/fmicb.2021.622235622235Effects of Hydrothermal Pretreatment and Hydrochar Addition on the Performance of Pig Carcass Anaerobic DigestionJie Xu0Jie Xu1Hongjian Lin2Kuichuan Sheng3School of City and Architecture Engineering, Zaozhuang University, Zaozhuang, ChinaCollege of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, ChinaCollege of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, ChinaCollege of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, ChinaProper disposal and utilization of dead pig carcasses are problems of public concern. The combination of hydrothermal pretreatment (HTP) and anaerobic digestion is a promising method to treat these wastes, provided that digestion inhibition is reduced. For this reason, the aim of this work was to investigate the optimal HTP temperature (140–180°C) for biogas production during anaerobic digestion of dead pigs in batch systems. In addition, the effects of hydrochar addition (6 g/L) on anaerobic digestion of pork products after HTP in continuous stirred tank reactors (CSTR) were determined. According to the results, 90% of lipids and 10% of proteins present in the pork were decomposed by HTP. In addition, the highest chemical oxygen demand (COD) concentration in liquid products (LP) reached 192.6 g/L, and it was obtained after 170°C HTP. The biogas potential from the solid residue (SR) and LP was up to 478 mL/g-VS and 398 mL/g-COD, respectively. A temperature of 170°C was suitable for pork HTP, which promoted the practical biogas yield because of the synergistic effect between proteins and lipids. Ammonia inhibition was reduced by the addition of hydrochar to the CSTR during co-digestion of SR and LP, maximum ammonia concentration tolerated by methanogens increased from 2.68 to 3.38 g/L. This improved total biogas yield and degradation rate of substrates, reaching values of 28.62 and 36.06%, respectively. The acetate content in volatile fatty acids (VFA) may be used as an index that reflects the degree of methanogenesis of the system. The results of the present work may also provide guidance for the digestion of feedstock with high protein and lipid content.https://www.frontiersin.org/articles/10.3389/fmicb.2021.622235/fullpig carcasshydrothermal temperaturehydrochar additionbiogas productionammonia inhibition |
| spellingShingle | Jie Xu Jie Xu Hongjian Lin Kuichuan Sheng Effects of Hydrothermal Pretreatment and Hydrochar Addition on the Performance of Pig Carcass Anaerobic Digestion Frontiers in Microbiology pig carcass hydrothermal temperature hydrochar addition biogas production ammonia inhibition |
| title | Effects of Hydrothermal Pretreatment and Hydrochar Addition on the Performance of Pig Carcass Anaerobic Digestion |
| title_full | Effects of Hydrothermal Pretreatment and Hydrochar Addition on the Performance of Pig Carcass Anaerobic Digestion |
| title_fullStr | Effects of Hydrothermal Pretreatment and Hydrochar Addition on the Performance of Pig Carcass Anaerobic Digestion |
| title_full_unstemmed | Effects of Hydrothermal Pretreatment and Hydrochar Addition on the Performance of Pig Carcass Anaerobic Digestion |
| title_short | Effects of Hydrothermal Pretreatment and Hydrochar Addition on the Performance of Pig Carcass Anaerobic Digestion |
| title_sort | effects of hydrothermal pretreatment and hydrochar addition on the performance of pig carcass anaerobic digestion |
| topic | pig carcass hydrothermal temperature hydrochar addition biogas production ammonia inhibition |
| url | https://www.frontiersin.org/articles/10.3389/fmicb.2021.622235/full |
| work_keys_str_mv | AT jiexu effectsofhydrothermalpretreatmentandhydrocharadditionontheperformanceofpigcarcassanaerobicdigestion AT jiexu effectsofhydrothermalpretreatmentandhydrocharadditionontheperformanceofpigcarcassanaerobicdigestion AT hongjianlin effectsofhydrothermalpretreatmentandhydrocharadditionontheperformanceofpigcarcassanaerobicdigestion AT kuichuansheng effectsofhydrothermalpretreatmentandhydrocharadditionontheperformanceofpigcarcassanaerobicdigestion |