Lu Feng
Research Scientist
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CVBiography
My research works primarily aim to strengthen anaerobic digestion based circular economy, the role of anaerobic digestion process on organic farming, its effect on recycling and relocating the nutrients, and impact on soil fertility and GHG emission. Currently, I have interests on developing innovative biotechnologies for converting organic residues, to bioenergy, organic acids, protein, biomethanation and syngas fermentation.
Authors
Lu FengAbstract
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Authors
Ararsa Derese Seboka Lu Feng John Morken Muyiwa S. Adaramola Getachew Birhanu Abera Gebresilassie Asnake EwunieAbstract
The growing hotel and education sectors in Ethiopia face increasing waste and energy demands, necessitating effective waste management and energy use strategies. This study is aimed to investigates biowaste production and energy consumption in hotels and university campuses in Southern Ethiopia, focusing on sustainable solutions for reducing environmental impacts. A mixed-methods approach, including surveys and onsite measurements, were used to assess energy consumption, biowaste generation, and management practices. A stratified purposive sampling was employed to select institutions, and both descriptive and inferential statistics, including time series analysis, multiple regression models, were applied; the environmental footprint of energy sources and energy potentials of biowastes were quantified following the guidelines set by the Intergovernmental Panel on Climate Change (IPCC).The study found that the primary energy sources for both sectors are electricity, natural gas/LPG, diesel fuel, fuelwood, and charcoal, with electricity being the dominant source. Hotels exhibit a consistent increase in energy consumption from 2016 to 2023, driven by tourism and service expansion, while university campuses show more fluctuating trends influenced by student enrollment and policy changes. Both sectors generate substantial biowaste annually—over 588 tons from hotels and 1448 tons from campuses—comprising food, fruit, vegetable and animal waste. However, waste management practices are often inadequate, with open dumping being common and the lack of energy recovery or treatment systems. The study quantified the greenhouse gas (GHG) emissions, found that non-electric energy sources such as oil fuels and firewood contribute significantly to CO2 emissions. In 2023, oil fuels accounted for 15,474.2 tonnes of CO2e, and firewood generated 130,377.2 tonnes CO2e, highlighting the need for cleaner energy alternatives to reduce emissions and reliance on carbon intensive energy sources.
Abstract
Upgrading biogas to biomethane could contribute to sustainable energy production, yet H2S may reduce the process efficiency and gas quality. This work examined the impact of H2S on biomethanation in batch assays and in continuous trickle bed reactor (TBR). The batch assay (not biofilm based) was conducted to quickly determine the threshold H2S concentration and to evaluate the inoculum's response to repeated H2S exposure. In contrast, the TBR experiment aimed to explore the role of biofilm-based biomethanation in mitigating H2S inhibition. Batch assays revealed significant inhibition, especially at higher H2S concentrations (3 %) and thermophilic temperatures (51 °C). In the batch assay, presence of H2S resulted in up to 30 % reduction in CH4 yield, decreasing from 229 to 160 NmL/Lreactor. Additionally, the CH4 content declined by 12 %, from 49 to 43 %. In contrast, TBRs showed resilience where TBRs fed with H2S-rich biogas produced effluent gas with 83.5 % CH4, similar to control (81.0 %). 16S rRNA analysis highlighted shifts toward sulphate reducing and sulphur oxidizing bacteria under H2S exposure, while acetogenic and syntrophic acetate-oxidizing bacteria increased in the control. This suggests potential competition for available substrates when subjected to H2S. These findings highlight that H2S significantly inhibits non-biofilm-based biomethanation, as seen in batch assays, although moderate acclimation was observed. However, biofilm-based process, e.g TBRs, effectively mitigate H2S toxicity, ensuring efficient biogas upgrading to biomethane.
