Browsing by Author "He, Yiliang"

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    Advancing the bioconversion process of food waste into methane: a systematic review
    (Elsevier, 2022-12-06) Workie, Endashaw; Kumar, Vinor; Bhatnagar, Amit; He, Yiliang; Dai, Yanjun; Tong, Yen Wah; Peng, Yinghong; Zhang, Jingxin; Fu, Cunbin
    With the continuous rise of food waste (FW) throughout the world, a research effort to reveal its potential for bioenergy production is surging. There is a lack of harmonized information and publications available that evaluate the state-of-advance for FW-derived methane production process, particularly from an engineering and sustainability point of view. Anaerobic digestion (AD) has shown remarkable efficiency in the bioconversion of FW to methane. This paper reviews the current research progress, gaps, and prospects in pre-AD, AD, and post-AD processes of FW-derived methane production. Briefly, the review highlights innovative FW collection and optimization routes such as AI that enable efficient FW valorization processes. As weather changes and the FW sources may affect the AD efficiency, it is important to assess the spatio-seasonal variations and microphysical properties of the FW to be valorized. In that case, developing weather-resistant bioreactors and cost-effective mechanisms to modify the raw substrate morphology is necessary. An AI-guided reactor could have high performance when the internal environment of the centralized operation is monitored in real-time and not susceptible to changes in FW variety. Monitoring solvent degradation and fugitive gases during biogas purification is a challenging task, especially for large-scale plants. Furthermore, this review links scientific evidence in the field with full-scale case studies from different countries. It also highlights the potential contribution of ADFW to carbon neutrality efforts. Regarding future research needs, in addition to the smart collection scheme, attention should be paid to the management and utilization of FW impurities, to ensure sustainable AD operations.
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    Mesophilic and thermophilic anaerobic digestion of animal manure: Integrated insights from biogas productivity, microbial viability and enzymatic activity
    (Elsevier, 2022-03-30) Zhang, Jingxin; Chen, Jiaqi; Ma, Ruize; Kumar, Vinod; Tong, Yen Wah; He, Yiliang; Mao, Feijian
    Anaerobic digestion (AD) is considered a promising technology for the sustainable management of current large quantities of animal waste. However, the efficiency and underlying mechanisms remain poorly understood, particularly regarding the different characteristics of different types of animal wastes. The present study investigated the methane production, community structure, microbial viability, and enzymatic activity following mesophilic and thermophilic AD of four types of animal waste, including carnivores (lion), herbivores (elephant), and omnivores (hippopotamus and orangutan). Methane yield obtained with thermophilic AD of four animals was higher than mesophilic ones. The methane yields of lion manure under the mesophilic and thermophilic AD were 0.326 L/g VS and 0.391 L/g VS, respectively, higher than that of herbivore and omnivore waste. Bacteria were divided into low-DNA (LDNA) and high-DNA (HDNA) bacteria by flow cytometry based on DNA content. Compared with mesophilic AD, thermophilic AD had higher cells density, which has the same trend with methane production. The results showed that the live LDNA bacteria abundance was increased by 98.6% in orangutan manure AD system after heating up to 55 ℃. However, most of the dead bacteria were HDNA, indicating sensitivity of HDNA cells to environmental conditions. For functional enzymes, the activities of dehydrogenase, phosphotransacetylase and protease were enhanced in the thermophilic AD system of all kinds of animal manure. Nevertheless, the acetate kinase activities of herbivorous animal manure and coenzyme F420 activities of omnivorous animal manure had been inhibited at high temperatures.