Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2023
Forfattere
Yi Zhang Zhangmu Jing Yijing Feng Shuo Chen Yeqing Li Yongming Han Lu Feng Junting Pan Mahmoud Mazarji Hongjun Zhou Xiaonan Wang Chunming XuSammendrag
Exploring key factors has important guidance for understanding complex anaerobic digestion (AD) systems. This study proposed a multi-layer automated machine learning framework to understand the complex interactions in AD systems and explore key factors at the environmental factor, microorganisms and system levels. The first layer of the framework identified hydraulic residence time (HRT) as the most important environmental factor, with an optimal range of 33–45 d. In the second layer of the framework, Methanocelleus (optimal relative abundance (ORA) = 3.0%) and Candidatus_Caldatribacterium (ORA = 1.7%) were found to be the key archaea and bacteria, respectively. Furthermore, the prediction of key microorganisms based on environmental factors and remaining microbial data showed the essential roles of Methanothermobacter and Acetomicrobium. The third layer for finding the optimal combination of data variables for predicting biogas production demonstrated that combined Archaea genera and environmental factors should be achieved for the most accurate prediction (root mean square error (RMSE) = 84.21). GBM had the best model performance and prediction accuracy among all the built-in models. Based on the optimal GBM model, the analysis at the system level showed that HRT was the most important variable. However the most important microorganism, Methanocelleus, within the appropriate survival range is also essential to achieve optimal biogas production. This research explores key parameters at various levels through automated machine learning techniques, which are expected to provide guidance in understanding the complex architecture of industrial and laboratory AD systems.
Sammendrag
NIBIO, NORSUS og Norwaste har vært involvert i et forskningsprosjekt finansiert av Handelens Miljøfond, som har tatt for seg bionedbrytbar plast og innsamlingsløsninger for matavfall i Norge. Forskerne fant at bionedbrytbar plast i svært liten grad brytes ned i biogassprosessen. Prosjektet pågikk fra juni 2022, sluttrapporten ble levert i august i år. NIBIO valgte de to mest brukte bionedbrytbare plastposene i Norge, og kjørte laboratorieforsøk der man så på nedbrytningen av disse under anaerob utråtning (biogassprosessen). Det ble først gjort forbehandling med termisk hydrolyse, og siden forsøk under såkalt termofile og mesofile forhold, altså med varmebehandling. – Vi hadde en ganske lang oppholdstid på 22 dager. Det store spørsmålet var om disse posene brytes ned under slike forhold. Det korte svaret er at det skjer i svært liten grad, sier NIBIO-forsker Claire Coutris til Biogassbransjen.no. Posene merket «hjemmekomposterbare» tapte maksimalt 33 prosent av opprinnelig vekt under termofile forhold, 55 grader. De som var markert «komposterbare i industriell kompostering» hadde et vekttap på 14-21 prosent. – Posene er nedbrytbare, men ikke under anaerob utråtning, sier Coutris. – Ved kompostering ved cirka 60 grader skal de bli borte i løpet av 6 måneder. Komposteringsprosesser foregår over mye lenger tid enn prosesser i biogassanlegg. Det var 4 prosent plast i matavfallet, som tilsvarer det man finner i faktisk produksjon, forteller Coutris. – Sannsynligvis vil det være behov for etterbehandling av biorest selv når matavfallet samles inn i bionedbrytbare poser. – Men vil det være noe problem å kjøre bioresten på jordet med bionedbrytbar plast, hvis den uansett brytes ned på sikt? – Disse posene er nedbrytbare under spesifikke forhold. Industriell kompost holder minst 60 grader i minst 4 uker. Jord holder sjelden mer enn 20 grader, og vi kan dermed ikke forvente at plasten brytes ned fort nok til at den ikke vil akkumuleres i jord. Coutris ser for seg videre forsøk hvor man kan bruke plastbitene fra forsøker i landbruksjord for å se hvor raskt de brytes ned under slike forhold.
Forfattere
Claire CoutrisSammendrag
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Forfattere
Yeqing Li Shasha Yu Xingru Yang Yijing Feng Liming Dong Yi Zhang Lu Feng Mahmoud Mazarji Junting PanSammendrag
In the anaerobic digestion (AD) process, the effects of humic acid (HA) derived from different feedstocks on AD are influenced by the variations in their structural composition and oxygen-containing functional groups. Thus, clarifying the structural differences of HA obtained from different feedstocks is crucial for understanding their impact on AD. In this study, the structure of five humic acids (HAs) derived from liquid digestate, food waste, silage corn straw, lignite and commercial HA, and their effects on AD were investigated. The study found that HA from food waste had more carboxyl groups, while straw-derived HA had more phenolic hydroxyl groups. Both types of HA had higher aromaticity and humification degree and showed significant inhibition effect on AD. HA from food waste had an average methanogenic inhibition rate of 43.5 % with 1 g/L HA added. In addition, commercial HA and HA derived from lignite had similar functional group types and aromaticity, with an average methanogenic inhibition rate of about 20 %. The study revealed that HAs with more carboxyl groups exhibited greater effectiveness in inhibiting AD, thereby confirming the influence of HA structures derived from different feedstocks on AD. In conclusion, this study provides valuable insights into the mechanism of HA effect on AD and offers guidance for future research focused on enhancing AD efficiency.
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Forfattere
Qiang Liu Yuanting Xu Yeqing Li Chengjie Ma Shuo Chen Lu Feng Quan Xu Junting Pan Bo Peng Hongjun Zhou Chunming XuSammendrag
Monophenols form humic acids (HA) through polycondensation reaction in the anaerobic digestion (AD) process, which will inhibit AD process. Currently, metal ions are the option for in-situ relieving HA inhibition during AD, but excess metal ions are harmful to microorganisms. In this study, carbon quantum dots (CQDs, a non-metallic materials) were proposed to relieve HA inhibition in-situ. We investigated the effect of HA on AD acidification and methanation stage, and synthesized CQDs using sodium citrate (s-CQDs) and p-phenylenediamine (p-CQDs) as precursors to relieve the HA inhibition in-situ. Results showed that s-CQDs (3.0 g/L) significantly increased the cumulative CH4 yield from AD of ethanol with 1.0 g/L HA (1.9 times higher than that without s-CQDs). Microbiological analysis indicated the most dominant methanogen was Methanosarcinaceae, with richness of 89.7%. Compared to the HA inhibition system, the relative abundance of Methanosarcinaceae increased by 87.5%. The analysis of interaction mechanism between CQDs and HA indicated that s-CQDs has an in-situ binding effect to HA by reacting with -OH, Cdouble bondC, and -COOH. This study provided a novel means for in-situ relieving HA inhibition, and illustrated the interaction mechanism between CQDs and HA, which will guide the application in production of bioenergy.