Enhancing the potential of wood waste as anaerobic digestion feedstock: a nature-based approach

Gao, Zhenghui 2024. Enhancing the potential of wood waste as anaerobic digestion feedstock: a nature-based approach. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

The aim of this study is to explore the enhancement of methane production in the anaerobic digestion of wood waste by leveraging forest soil systems as a ‘pre’ treatment. A nature-based approach can provide valuable insights for managing forest residues and promoting resource recovery, making anaerobic digestion a viable wood waste management practice. Due to the recalcitrant lignocellulosic structure of wood waste, its use as a substrate for anaerobic digestion is not commonly pursued in mainstream research. Therefore, a detailed meta-analysis was conducted to compare the anaerobic digestion potential of wood waste with other organic wastes and to demonstrate the degree of enhancement in methane production from wood waste using various pretreatment technologies. Considering that anaerobic digestion parameters can significantly impact methane production, it is essential to optimize the conditions during the anaerobic fermentation process. To achieve this, machine learning techniques were employed to analyze and fine-tune the digestion parameters specifically for wood waste. In the case of current wood waste pretreatment technologies, most are limited to the laboratory level, often overlooking labour and capital costs, rendering them impractical for operational use. For this reason, naturally decayed wood samples from forests were collected for further tests, which were classified into one of five decay classes (numbered 1-5 with increasing decay) based on a range of characteristics. Additionally, the study examined the impact of forest environmental factors on the degradation of wood waste and subsequent methane production by placing two types of wood waste in two types of vegetation zones in the forest. IV The following conclusions can be drawn. Firstly, pretreatment technologies significantly enhance methane production from wood waste, making it a viable raw material for anaerobic digestion. It has been observed that employing a combination of pretreatment techniques is more effective than using a single method. In addition, the random forest algorithm can reliably predict methane yield from anaerobic digestion of wood waste. Critical factors influencing methane production include wood particle size and the substrate-to-inoculum ratio. Moreover, decayed wood samples showed a range of physicochemical properties conducive to anaerobic digestion, with decay class 3 showing the highest methane yield. Lastly, different forest environments affect the degradation of wood, although a specific treatment time is necessary to significantly impact its methane production.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Engineering
Uncontrolled Keywords:	1).Anaerobic digestion 2). Wood waste 3).Methane production 4).Forest soil system 5).Nature-based approach
Date of First Compliant Deposit:	15 April 2025
Last Modified:	15 Apr 2025 15:03
URI:	https://orca.cardiff.ac.uk/id/eprint/177708

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