The contaminants in biogas reduce the fuel’s calorific value, wear down and corrode metallic components, and limit its application in equipment. This study is concerned with upgrading biogas through optimization of parameters in anaerobic co-digestion of cow dung (CD) with banana peel waste (BP), mixed food waste (FW), and poultry manure (PM). The results suggested that response surface methodology (RSM) to increase the concentration of CH4 by parameter optimization involves eliminating H2S using activated carbon and lowering CO2 concentration using NaOH solution. The data from the optimization experiment was analyzed and modeled using Design-Expert version 13 with two numerical factors, temperature (25–45 °C) and retention time (25–30 days), and one categorical factor, substrate type (75% CD:25% BP), (50% CD:50% FW), and (75% CD:25% PM) coded as A, B, and C, respectively. Significance was then accepted at a 0.05 level of probability (P < 0.05). Analyzing the experimental trial data yielded highly statistically significant regression model equations with R2 = 0.9991, R2 = 0.9988, and R2 = 0.9991 for CH4, CO2, and H2S, respectively. As a result, for substrates A, B, and C, respectively, the methane content rose to 96.42%, 94.37%, and 92.31% at 35 <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13399_2025_6757_Article_IEq1.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="20" /> </InlineMediaObject> <EquationSource Format="TEX">$^\circ \text{C}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> <mtext>C</mtext> </mrow> </math></EquationSource> </InlineEquation> and 22.5 days. The calorific value of upgraded biogas was 34.61 MJ/m3, 33.87 MJ/m3, and 33.22 MJ/m3 for substrates A, B, and C, respectively. Based on the testing results, a chemical purification and physical adsorption approach would be the best way to upgrade biogas by raising the CH4 concentration.

Biogas upgrading produced through anaerobic co-digestion of organic biowastes: a comparative study

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2025年3月23日

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Gebrehiwot Kunom Hagos,
Wondalem Misganaw Golie,
Fentahun Abebaw Belete,
Yared Hagos Gidey

摘要

The contaminants in biogas reduce the fuel’s calorific value, wear down and corrode metallic components, and limit its application in equipment. This study is concerned with upgrading biogas through optimization of parameters in anaerobic co-digestion of cow dung (CD) with banana peel waste (BP), mixed food waste (FW), and poultry manure (PM). The results suggested that response surface methodology (RSM) to increase the concentration of CH₄ by parameter optimization involves eliminating H₂S using activated carbon and lowering CO₂ concentration using NaOH solution. The data from the optimization experiment was analyzed and modeled using Design-Expert version 13 with two numerical factors, temperature (25–45 °C) and retention time (25–30 days), and one categorical factor, substrate type (75% CD:25% BP), (50% CD:50% FW), and (75% CD:25% PM) coded as A, B, and C, respectively. Significance was then accepted at a 0.05 level of probability (P < 0.05). Analyzing the experimental trial data yielded highly statistically significant regression model equations with R² = 0.9991, R² = 0.9988, and R² = 0.9991 for CH₄, CO₂, and H₂S, respectively. As a result, for substrates A, B, and C, respectively, the methane content rose to 96.42%, 94.37%, and 92.31% at 35 $^\circ \text{C}$ $^{\circ} C$ and 22.5 days. The calorific value of upgraded biogas was 34.61 MJ/m³, 33.87 MJ/m³, and 33.22 MJ/m³ for substrates A, B, and C, respectively. Based on the testing results, a chemical purification and physical adsorption approach would be the best way to upgrade biogas by raising the CH₄ concentration.