<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Publishing DTD v1.4 20241031//EN" "JATS-journalpublishing1-4.dtd">
<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" dtd-version="1.4" xml:lang="en">
  <front>
    <journal-meta>
      <journal-id journal-id-type="publisher-id">abb</journal-id>
      <journal-title-group>
        <journal-title>Advances in Bioscience and Biotechnology</journal-title>
      </journal-title-group>
      <issn pub-type="epub">2156-8502</issn>
      <issn pub-type="ppub">2156-8456</issn>
      <publisher>
        <publisher-name>Scientific Research Publishing</publisher-name>
      </publisher>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="doi">10.4236/abb.2026.174010</article-id>
      <article-id pub-id-type="publisher-id">abb-150768</article-id>
      <article-categories>
        <subj-group>
          <subject>Article</subject>
        </subj-group>
        <subj-group>
          <subject>Biomedical</subject>
          <subject>Life Sciences</subject>
        </subj-group>
      </article-categories>
      <title-group>
        <article-title>Pilot Production of Biogas from Vegetable Waste for Energy Self-Sufficiency in Households in Ouagadougou Peri-Urban Area, Burkina Faso</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author" corresp="yes">
          <name name-style="western">
            <surname>Makaya</surname>
            <given-names>Joseph M.</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <name name-style="western">
            <surname>Mogmenga</surname>
            <given-names>Iliassou</given-names>
          </name>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <name name-style="western">
            <surname>Nikiéma</surname>
            <given-names>Mahamadi</given-names>
          </name>
          <xref ref-type="aff" rid="aff3">3</xref>
        </contrib>
        <contrib contrib-type="author">
          <name name-style="western">
            <surname>Traoré</surname>
            <given-names>Désiré</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
      </contrib-group>
      <aff id="aff1"><label>1</label> Laboratory of Sciences and Technologies, New Dawn University, Bobo-Dioulasso, Burkina Faso </aff>
      <aff id="aff2"><label>2</label> University Center of Banfora, University Nazi Boni, Bobo Dioulasso, Burkina Faso </aff>
      <aff id="aff3"><label>3</label> Higher Institute of Sustainable Development (HISD), University of Yembila Abdoulaye TOGUYENI, Fada N’Gourma, Burkina Faso </aff>
      <author-notes>
        <fn fn-type="conflict" id="fn-conflict">
          <p>The authors declare no conflicts of interest regarding the publication of this paper.</p>
        </fn>
      </author-notes>
      <pub-date pub-type="epub">
        <day>13</day>
        <month>04</month>
        <year>2026</year>
      </pub-date>
      <pub-date pub-type="collection">
        <month>04</month>
        <year>2026</year>
      </pub-date>
      <volume>17</volume>
      <issue>04</issue>
      <fpage>140</fpage>
      <lpage>156</lpage>
      <history>
        <date date-type="received">
          <day>02</day>
          <month>03</month>
          <year>2026</year>
        </date>
        <date date-type="accepted">
          <day>13</day>
          <month>04</month>
          <year>2026</year>
        </date>
        <date date-type="published">
          <day>16</day>
          <month>04</month>
          <year>2026</year>
        </date>
      </history>
      <permissions>
        <copyright-statement>© 2026 by the authors and Scientific Research Publishing Inc.</copyright-statement>
        <copyright-year>2026</copyright-year>
        <license license-type="open-access">
          <license-p> This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( <ext-link ext-link-type="uri" xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link> ). </license-p>
        </license>
      </permissions>
      <self-uri content-type="doi" xlink:href="https://doi.org/10.4236/abb.2026.174010">https://doi.org/10.4236/abb.2026.174010</self-uri>
      <abstract>
        <p>Inadequate solid waste management, particularly organic waste from markets, represents a major environmental and health challenge at Ouagadougou in Burkina Faso. The aim of the study was to produce biogas from plant waste to achieve energy self-sufficiency in the Burkina Ouagadougou peri-urban areas. The methodology involves the collection and physicochemical characterization of vegetable waste. A 200-liter pilot biodigester equipped with a meter, a biogas storage chamber, and a stove designed by the Albert Schweitzer International Centre (CEAS) was used for the tests. Anaerobic digestion was carried out, including an acclimatization phase with cow manure alone, followed by the addition of different proportions of substrate (1/3, 1/2, and 3/4 after 24 hours of pre-fermentation). Anaerobic digestion was monitored in terms of the volume of biogas produced, its composition (CH<sub>4</sub>, CO<sub>2</sub>, H<sub>2</sub>S), and changes in the pH and volatile fatty acids (VFA) of the digestate. The results of the physicochemical parameters show average contents of dry matter (DM) and volatile dry matter (VDM) of 6.20% and 78.88%, respectively. A C/N ratio of 5.47 was obtained, indicating an ideal substrate for biogas production. Cow manure alone generates the highest average volume of biogas (7.42 dm<sup>3</sup>/day), but co-digestion with vegetable waste significantly improves the quality of the biogas. An overall assessment of the digester’s performance shows good energy yield. The digestate pH remains stable (7.31 - 7.50), and H<sub>2</sub>S levels are low (peaking at 37 ppm). Therefore, the technology is technically reliable, but its long-term productivity depends on proper operational management, particularly substrate supply.</p>
      </abstract>
      <kwd-group kwd-group-type="author-generated" xml:lang="en">
        <kwd>Vegetable Waste</kwd>
        <kwd>Anaerobic Digestion</kwd>
        <kwd>Biogas</kwd>
        <kwd>Domestic Energy</kwd>
        <kwd>Peri-Urban Area</kwd>
        <kwd>Ouagadougou</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec1">
      <title>1. Introduction</title>
      <p>The city of Ouagadougou, capital of Burkina Faso, is undergoing rapid urbanization and sustained population growth, leading to an exponential increase in municipal solid waste production [<xref ref-type="bibr" rid="B1">1</xref>]. Within this waste stream, vegetables, mainly from households, markets and agri-food units, represent a significant and particularly problematic fraction [<xref ref-type="bibr" rid="B2">2</xref>]. Indeed, the current management of this bio-waste is largely deficient. According to the United Nations Environment Programme, the city’s markets produce considerable volumes of waste every day, only a small proportion of which is collected and treated properly [<xref ref-type="bibr" rid="B3">3</xref>]. This situation has a negative impact on the environment and the population’s health. The accumulation of this waste in the open air promotes the proliferation of disease vectors, odor pollution, and soil and water contamination by leachates. In addition, its uncontrolled anaerobic decomposition is a source of methane emissions, a powerful greenhouse gas [<xref ref-type="bibr" rid="B4">4</xref>][<xref ref-type="bibr" rid="B5">5</xref>]. This dual health and environmental challenge is compounded by a serious energy problem. Indeed, as in other countries of the West African Economic and Monetary Union (WAEMU), access to modern energy in Burkina Faso remains limited, with a major dependence on traditional biomass such as firewood and charcoal, which accounts for 74% of national energy consumption according to Chitou and Gbandey [<xref ref-type="bibr" rid="B6">6</xref>]. The majority of the population (around 81%) still depends on wood energy (firewood and charcoal). In rural areas, almost all of the energy consumed comes from biomass. The national average is therefore 0.69 kg of firewood per person per day [<xref ref-type="bibr" rid="B7">7</xref>]. The vast majority of households use wood and charcoal for cooking, contributing to deforestation and air pollution. This dependence has negative health consequences, including water pollution and sanitation problems, and creates gender inequalities, as women are responsible for collecting wood. In the face of these challenges, waste recovery through anaerobic digestion appears to be a strategic approach, as it offers a simultaneous response to sanitation and energy access issues. </p>
      <p>Globally, the high methanogenic potential of fruit and vegetable waste is well documented, with fruit and vegetable waste identified as the most wasted food category worldwide by Gustavsson <italic>et al</italic>. [<xref ref-type="bibr" rid="B8">8</xref>] and Bouzid <italic>et al</italic>. [<xref ref-type="bibr" rid="B9">9</xref>]. Biochemical characterization studies show that this waste is mainly composed of highly fermentable elements such as leaves and peelings [<xref ref-type="bibr" rid="B9">9</xref>]-[<xref ref-type="bibr" rid="B11">11</xref>], making it a substrate of choice for biogas production. In Burkina Faso, pioneering work has already demonstrated the technical feasibility of producing biogas from various local resources. This is particularly the case in the study conducted by Traoré <italic>et al</italic>. [<xref ref-type="bibr" rid="B12">12</xref>], which specifically assessed the biomethane potential of vegetable waste, confirming the interest in this resource. The work of Makaya <italic>et al</italic>. [<xref ref-type="bibr" rid="B13">13</xref>] showed the possibility of optimizing biomethane production from vegetable waste from “yaars” and markets at Ouagadougou in Burkina Faso. An optimal yield of 3540 L CH<sub>4</sub>/kg was obtained by Makaya <italic>et al</italic>. [<xref ref-type="bibr" rid="B13">13</xref>], demonstrating the high biomethanogenic potential of this vegetable waste from “yaars” and markets. Technology transfer could enable peri-urban households to produce energy to meet their energy needs. The objective of the study was to produce biogas from plant waste to achieve energy self-sufficiency in peri-urban areas of Burkina Faso.</p>
    </sec>
    <sec id="sec2">
      <title>2. Materials and Methods</title>
      <sec id="sec2dot1">
        <title>2.1. Sampling and Preparation of Vegetable Waste</title>
        <p>The vegetable waste samples were collected from two places in Ouagadougou, at the “Zongo” market (12˚20'13.5''N, 1˚35'45.4''W) and at the “Cité An II” one (12˚20'13.5''N, 1˚35'45.4''W). A total of 200 kg of vegetable waste, corresponding to four 50 kg bags, was collected over a period of one week to ensure a constant supply during the tests. To meet one of the study’s objectives, which was to determine the physicochemical parameters of the samples, the vegetable waste (cabbage leaves) underwent pre-treatment followed by a series of analyses (<xref ref-type="fig" rid="fig1">Figure 1</xref>). The inoculum used to start the methanization process was fresh cattle manure. It is known for its richness in methanogenic microorganisms that promote the degradation of organic matter and the production of methane. The cattle manure was collected from local farmers located near the experimental site. The collected biomass was dried in the sun for several days and then ground to obtain a homogeneous and easily digestible material. The resulting ground material underwent 24 hours of pre-fermentation to trigger the biological processes. </p>
        <fig id="fig1">
          <label>Figure 1</label>
          <graphic xlink:href="https://html.scirp.org/file/7302255-rId15.jpeg?20260416025048" />
        </fig>
        <fig id="fig2">
          <label>Figure 2</label>
          <graphic xlink:href="https://html.scirp.org/file/7302255-rId16.jpeg?20260416025048" />
        </fig>
        <fig id="fig3">
          <label>Figure 3</label>
          <graphic xlink:href="https://html.scirp.org/file/7302255-rId17.jpeg?20260416025048" />
        </fig>
        <p>(a) (b) (c)</p>
        <p><bold>Figure 1.</bold> Preparation of waste samples: (a) fresh vegetable waste, (b) dried samples, (c) shredded vegetable waste.</p>
      </sec>
      <sec id="sec2dot2">
        <title>2.2. Characterization of the Substrate</title>
        <p>The physicochemical parameters of the vegetable waste powder (substrate) were analyzed using recognized methods to assess its biodegradation potential. The pH was measured according to the method of Nout <italic>et al</italic>. [<xref ref-type="bibr" rid="B14">14</xref>] on a sample homogenized with distilled water using a previously calibrated pH meter. The ashes were obtained by incinerating the dry matter at 550˚C. The volatile dry matter was calculated by weighing the difference between the mass after passage through the oven and the mass of the waste calcined at 550˚C in the furnace, which also allowed the total carbon content to be estimated according to the theoretical VDM/TOC ratio, generally estimated at 1.74 [<xref ref-type="bibr" rid="B15">15</xref>]. Lipids were extracted using the Soxhlet method with hexane, followed by evaporation of the solvent and weighing after drying. Insoluble lignin was determined according to TAPPI 222 [<xref ref-type="bibr" rid="B16">16</xref>] after acid hydrolysis and vacuum filtration. Finally, the carbohydrate content was measured using the colorimetric method of Dubois <italic>et al</italic>. [<xref ref-type="bibr" rid="B17">17</xref>], involving a reaction with phenol and sulfuric acid before reading with a spectrophotometer. </p>
      </sec>
      <sec id="sec2dot3">
        <title>2.3. Experimental Setup</title>
        <p>The experiment was conducted using a batch-type pilot biodigester designed by the Albert Schweitzer Ecological Center (CEAS). The main reactor consists of a plastic barrel with a total volume of 200 L, sealed to ensure strict anaerobic conditions (<xref ref-type="fig" rid="fig2">Figure 2</xref>). An opening was made in the top of the barrel lid to serve as a feed pipe equipped with a valve, and another opening with a valve was made in the barrel to serve as a spillway. The barrel was hermetically sealed and glued to prevent any leaks. The digester is equipped with a barometer to measure the pressure inside the digester. The device is connected via a pipe equipped with valves to a J2.5 meter to quantify the gas produced, an air chamber to contain the gas produced, a furnace equipped with a gas burner, and a barometer to measure the pressure.</p>
        <fig id="fig4">
          <label>Figure 4</label>
          <graphic xlink:href="https://html.scirp.org/file/7302255-rId18.jpeg?20260416025049" />
        </fig>
        <p><bold>Figure 2.</bold> Biodigester and accessories.</p>
      </sec>
      <sec id="sec2dot4">
        <title>2.4. Start-Up of the Biodigester</title>
        <p>The reaction volume of the biodigester represents two-thirds of the barrel’s volume. The digester was fed sequentially after two weeks of biogas production (<xref ref-type="fig" rid="fig3">Figure 3</xref>). The initial feed consisted solely of cattle manure diluted in water in equal proportions (1 kg of cattle manure in 1 liter of water). The mixture was introduced into the digester through the feed pipe equipped with a safety valve, ensuring efficient feeding of the hermetically sealed barrel. After each substrate depletion marked by a drop in biogas production, a new substrate pre-fermented at 2% (m/v) was added successively to 1/3, 1/2, and 3/4 of the reaction volume. </p>
        <fig id="fig5">
          <label>Figure 5</label>
          <graphic xlink:href="https://html.scirp.org/file/7302255-rId19.jpeg?20260416025049" />
        </fig>
        <p><bold>Figure 3.</bold> Digester feed-digester emptying.</p>
      </sec>
      <sec id="sec2dot5">
        <title>2.5. Monitoring of Anaerobic Digestion</title>
        <p>A Direct Soil pH meter, equipped with an electrode whose probe is immersed in a KCl solution, was used to monitor the pH and temperature during anaerobic digestion. The gas produced was monitored using the GEMBIO biogas analyzer. This device measures the content of the various components of biogas, namely methane (CH<sub>4</sub>), carbon dioxide (CO<sub>2</sub>), and hydrogen sulfide (H<sub>2</sub>S). The cumulative volume of biogas was measured continuously using a gas meter (<xref ref-type="fig" rid="fig4">Figure 4(d)</xref>). The volume produced between two readings was calculated as the difference between the final and initial volumes.</p>
        <fig id="fig6">
          <label>Figure 6</label>
          <graphic xlink:href="https://html.scirp.org/file/7302255-rId20.jpeg?20260416025049" />
        </fig>
        <p><bold>Figure 4.</bold> Biogas analysis equipment. Legend: (a) GEMBIO biogas analyzer; (b) air chamber for biogas storage; (c) barometer; (d) gas meter.</p>
        <p>The gas produced is stored in the air chamber (<xref ref-type="fig" rid="fig4">Figure 4(b)</xref>). Periodic analyses were performed using the GEMBIO analyzer to determine the CH<sub>4</sub>, CO<sub>2</sub>, and H<sub>2</sub>S content (<xref ref-type="fig" rid="fig4">Figure 4(a)</xref>). The barometer was used to measure the pressure in the digester (<xref ref-type="fig" rid="fig4">Figure 4(c)</xref>).</p>
      </sec>
      <sec id="sec2dot6">
        <title>2.6. Monitoring Parameters during Anaerobic Digestion</title>
        <p><bold>pH</bold></p>
        <p>A Direct Soil pH meter, equipped with an electrode whose probe is immersed in a KCl solution, was used to measure the pH and temperature of the pre-fermented substrate and digestate. </p>
        <p><bold>Volatile</bold><bold>Fatty</bold><bold>Acids</bold><bold>(VFA)</bold></p>
        <p>Each time the tank was emptied, a quantity of digestate was taken and stored in the freezer for volatile fatty acid analysis. The measurement was carried out using a 25 mL supernatant taken after agitation. The initial pH was measured, then the mixture was acidified with sulfuric acid (H<sub>2</sub>SO<sub>4</sub> at 0.1 mol/L) until a pH of 4 was reached (volume noted as <italic>V</italic><sub>1</sub>). The solution was then boiled for 3 minutes and cooled. Neutralization was then carried out using a sodium carbonate solution (Na<sub>2</sub>CO<sub>3</sub> at 0.05 mol/L) to a pH of 7 (volume noted as <italic>V</italic><sub>2</sub>). The VFA concentration was calculated using the following formula:</p>
        <disp-formula id="FD1">
          <mml:math display="inline">
            <mml:mrow>
              <mml:mtext>AGV</mml:mtext>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mrow>
                  <mml:mrow>
                    <mml:mtext>g</mml:mtext>
                    <mml:mo>/</mml:mo>
                    <mml:mtext>L</mml:mtext>
                  </mml:mrow>
                </mml:mrow>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>=</mml:mo>
              <mml:mn>6</mml:mn>
              <mml:mo>×</mml:mo>
              <mml:msup>
                <mml:mrow>
                  <mml:mn>10</mml:mn>
                </mml:mrow>
                <mml:mn>4</mml:mn>
              </mml:msup>
              <mml:mo>×</mml:mo>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mrow>
                  <mml:mrow>
                    <mml:mrow>
                      <mml:mrow>
                        <mml:mo>(</mml:mo>
                        <mml:mrow>
                          <mml:msub>
                            <mml:mi>C</mml:mi>
                            <mml:mn>2</mml:mn>
                          </mml:msub>
                          <mml:mo>×</mml:mo>
                          <mml:msub>
                            <mml:mi>V</mml:mi>
                            <mml:mn>2</mml:mn>
                          </mml:msub>
                        </mml:mrow>
                        <mml:mo>)</mml:mo>
                      </mml:mrow>
                    </mml:mrow>
                    <mml:mo>/</mml:mo>
                    <mml:mi>E</mml:mi>
                  </mml:mrow>
                </mml:mrow>
                <mml:mo>)</mml:mo>
              </mml:mrow>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>where:</p>
        <p><italic>C</italic><sub>2</sub>: concentration of Na<sub>2</sub>CO<sub>3</sub> (mol/L);<italic>V</italic><sub>2</sub>: volume of Na<sub>2</sub>CO<sub>3</sub> added (L);<italic>E</italic>: sample volume (mL).</p>
      </sec>
      <sec id="sec2dot7">
        <title>2.7. Data Analysis</title>
        <p>Data entry, means, and standard deviations were calculated using Excel 2016. Standard deviation measures the variability of observations. The effect of time on daily biogas production and its components (CO<sub>2</sub>, H<sub>2</sub>S, CH<sub>4</sub>) was assessed using a mixed linear model that took into account the temporal dependence of repeated measurements. STATA 2017 and Python 3.2 analysis software were used.</p>
      </sec>
    </sec>
    <sec id="sec3">
      <title>3. Results</title>
      <sec id="sec3dot1">
        <title>3.1. Physicochemical Parameters of Vegetable Waste</title>
        <p><bold>Table 1</bold> shows the results of physicochemical analyses of the substrate. The relatively low dry matter content (6.20%) indicates a high moisture content that promotes microbial activity. The ash content of 16.23% corresponds to the mineral fraction of the substrate. The volatile dry matter content of 78.88% indicates the organic fraction of the substrate, which is essential for biogas production. A high percentage is favorable for biodegradation. The total carbon content of 45.34% shows a high concentration of organic carbon, a key parameter for fermentation and methane production. The total nitrogen content of 8.28 mg/g influences the C/N ratio and the availability of nutrients for the microorganisms responsible for biodigestion. Lipids, at a moderate concentration (3.58%), can influence the process by providing a source of energy. Lignin (13.5%) is a complex compound that is difficult to degrade; a high content can limit the biodegradability of the substrate and require pre-treatment. The C/N ratio is relatively low (5.47), which could indicate an excess of nitrogen, requiring adjustment of the substrate to optimize biogas production.</p>
        <p><bold>Table 1.</bold>Physicochemical parameters of the substrate.</p>
        <table-wrap id="tbl1">
          <label>Table 1</label>
          <table>
            <tbody>
              <tr>
                <td>
                  <bold>Parameter</bold>
                </td>
                <td>
                  <bold>Unit</bold>
                </td>
                <td>
                  <bold>Average</bold>
                  <bold>Values</bold>
                </td>
              </tr>
              <tr>
                <td>Dry matter</td>
                <td>%</td>
                <td>6.20 ± 0.49</td>
              </tr>
              <tr>
                <td>Total ash</td>
                <td>%</td>
                <td>16.23 ± 0.17</td>
              </tr>
              <tr>
                <td>Volatile dry matter</td>
                <td>%</td>
                <td>78.88 ± 0.37</td>
              </tr>
              <tr>
                <td>Total carbon</td>
                <td>%</td>
                <td>45.34 ± 0.21</td>
              </tr>
              <tr>
                <td>Total nitrogen</td>
                <td>mg/g</td>
                <td>8.28</td>
              </tr>
              <tr>
                <td>C/N ratio</td>
                <td>-</td>
                <td>5.47</td>
              </tr>
              <tr>
                <td>Lipid</td>
                <td>%</td>
                <td>3.58 ± 0.33</td>
              </tr>
              <tr>
                <td>Lignin</td>
                <td>%</td>
                <td>13.5</td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
      </sec>
      <sec id="sec3dot2">
        <title>3.2. Evaluation of Biogas Productivity and Quality</title>
        <p><bold>Physicochemical</bold><bold>Parameters</bold><bold>of</bold><bold>Digestate</bold></p>
        <p><bold>Table 2</bold> shows the results of analyses of the physicochemical parameters of the digestate. Manure has a lower dry matter content (91.71) than the others. Ash represents the amount of mineral matter present after incineration. A low ash content, such as that found in feeds 1/3, 1/2, and 3/4, indicates a higher proportion of organic matter that is likely to be degraded during anaerobic digestion. Volatile dry matter (VDM) and total carbon (TOC) indicate the organic fraction of the substrate, which is essential for biogas production. A decrease in values in the different proportions of the substrate compared to manure. Volatile fatty acids (VFAs) are by-products of organic degradation and influence the efficiency of the anaerobic digestion process. Too high a concentration can inhibit methane production. The 1/3 substrate feed has the highest concentration of VFA, which can influence its biodegradability. A stable pH between 6.5 and 7.5 is optimal for anaerobic digestion. All the pH values in this table are within the range that is considered to be good. An increase in the substrate feed ratio of 3:4 could indicate an advanced digestion process or weaker acidification.</p>
        <p><bold>Table 2.</bold> Physicochemical parameters of digestate.</p>
        <table-wrap id="tbl2">
          <label>Table 2</label>
          <table>
            <tbody>
              <tr>
                <td>Sample</td>
                <td>pH</td>
                <td>Dry Matter(%)</td>
                <td>Total Ash (%)</td>
                <td>Volatile Dry Matter (%)</td>
                <td>Total Carbon (%)</td>
                <td>Volatile Fatty Acids (mg/L)</td>
              </tr>
              <tr>
                <td>Cow manure (CM)</td>
                <td>7.31</td>
                <td>91.71 ± 0.27</td>
                <td>2.45 ± 0.06</td>
                <td>5.85 ± 0.21</td>
                <td>3.36 ± 0.12</td>
                <td>96.00</td>
              </tr>
              <tr>
                <td>CM + 1/3 of substrate (v/v)</td>
                <td>7.34</td>
                <td>96.54 ± 0.42</td>
                <td>1.13 ± 0.12</td>
                <td>2.33 ± 0.29</td>
                <td>1.34 ± 0.17</td>
                <td>132.00</td>
              </tr>
              <tr>
                <td>CM + 1/2 of substrate (v/v)</td>
                <td>7.42</td>
                <td>99.36 ± 0.06</td>
                <td>0.27 ± 0.02</td>
                <td>0.37 ± 0.04</td>
                <td>0.21 ± 0.02</td>
                <td>84.00</td>
              </tr>
              <tr>
                <td>CM + 3/4 of substrate (v/v)</td>
                <td>7.50</td>
                <td>99.28 ± 0.01</td>
                <td>0.31 ± 0.01</td>
                <td>0.40 ± 0.003</td>
                <td>0.23 ± 0.001</td>
                <td>39.60</td>
              </tr>
            </tbody>
          </table>
        </table-wrap>
        <p><bold>Biogas</bold><bold>Volume</bold><bold>Produced</bold><bold>over</bold><bold>Time</bold></p>
        <p>The production of biogas was monitored under four conditions: manure alone (at start-up) and three increasing proportions of vegetable waste (1/3, 1/2, and 3/4). <xref ref-type="fig" rid="fig5">Figure 5</xref> shows the volume of biogas produced during our experiment. It allowed us to assess the volume of biogas produced by our four feedings. Cow manure alone generated the highest average volume of biogas (7.42 dm<sup>3</sup>/day). The gradual introduction of vegetable waste led to a decrease in the total daily volume of biogas. When the ratio was 1:2, the average daily biogas production was 5.42 dm<sup>3</sup>/day. The 1:3 ratio feed curve shows that biogas production stabilizes at 3 dm<sup>3</sup> from the fifth to the ninth day.</p>
        <fig id="fig7">
          <label>Figure 7</label>
          <graphic xlink:href="https://html.scirp.org/file/7302255-rId23.jpeg?20260416025051" />
        </fig>
        <p><bold>Figure 5.</bold> Change in the quantity of biogas.</p>
      </sec>
      <sec id="sec3dot3">
        <title>3.3. Quality of Biogas Produced over Time</title>
        <p><bold>Monitoring</bold><bold>of</bold><bold>Methane</bold><bold>Content</bold></p>
        <p>As illustrated in <xref ref-type="fig" rid="fig6">Figure 6(a)</xref>, there has been a notable evolution in the methane content. Following the commencement of methane production, the manure feed curve demonstrates a substantial increase, reaching 57% from the sixth day onwards. From the thirteenth day onwards, the process stabilizes until the end of production. The incorporation of vegetable waste had a highly beneficial effect on the quality of the biogas. The curve representing the methane content of the feed at one-third of the substrate is shown in orange. It is characterized by an initial methane content that exceeds that of manure alone, suggesting an enhancement in methane content through co-digestion. The content rises rapidly and reaches approximately 60% from the ninth day onwards before stabilizing. The feed at half of the substrate, as shown by the grey curve, demonstrates a rapid and significant increase, reaching almost 70% in less than 10 days. Following this growth phase, the next stage is to stabilize at this high content level. This biogas content is considered to be of very good quality. Finally, feeding with 3:4 of the substrate (yellow curve) increased to reach a peak of around 67% after six days. Following this peak, production stabilizes until the end of the process. The observed decline in CH<sub>4</sub> production may be attributable to the depletion of the substrate available to methanogenic bacteria. <xref ref-type="fig" rid="fig6">Figure 6(b)</xref> shows the evolution of the carbon dioxide content, which has a generally opposite trend to that of methane. The manure curve starts with a relatively low percentage of CO<sub>2</sub>, then increases to around 46%, before decreasing again to stabilize at around 40%. The curve representing 1:3 of the substrate shows initial variations. It starts at its peak at 40%, decreases, and then stabilizes. The grey curve starts at a much higher percentage than the manure curve, which has a substrate ratio of 1:2. The manure curve also has a substrate ratio of 1:3. It quickly reaches its highest point at 61% before dropping significantly to reach the lowest content of the entire production. The curve for the 3:4 ratio of substrate starts at 60% and then quickly goes down to around 30% before it starts to stabilize. <xref ref-type="fig" rid="fig6">Figure 6</xref> shows the total amount of CO<sub>2</sub> and CH<sub>4</sub> produced during anaerobic digestion. It shows a big drop in CO<sub>2</sub> levels during the 15 days of incubation, along with a rise in CH<sub>4</sub> levels, suggesting that CO<sub>2</sub> is being turned into CH<sub>4</sub>. Studies have shown that hydrogenotrophic methanogenic bacteria use molecular hydrogen to reduce CO<sub>2</sub> to CH<sub>4</sub> [<xref ref-type="bibr" rid="B18">18</xref>][<xref ref-type="bibr" rid="B19">19</xref>].</p>
        <fig id="fig8">
          <label>Figure 8</label>
          <graphic xlink:href="https://html.scirp.org/file/7302255-rId24.jpeg?20260416025051" />
        </fig>
        <p>(a)</p>
        <fig id="fig9">
          <label>Figure 9</label>
          <graphic xlink:href="https://html.scirp.org/file/7302255-rId25.jpeg?20260416025051" />
        </fig>
        <p>(b)</p>
        <p><bold>Figure 6.</bold> Change in (a) methane and (b) carbon dioxide content.</p>
        <p><bold>Monitoring</bold><bold>of</bold><bold>Hydrogen</bold><bold>Sulfide</bold><bold>Content</bold></p>
        <p><xref ref-type="fig" rid="fig7">Figure 7</xref> shows the hydrogen sulfide content in biogas during experiments. Unlike the other graphs, the hydrogen sulfide concentration remained at very low levels for all feeds (maximum average of 9 ppm), preventing equipment corrosion and toxicity problems for the microbial consortium. The blue curve representing manure starts at zero and increases slightly to reach its peak at 12 ppm before falling back to zero. The red curve representing the 1/3 substrate feed starts with a peak at 4 ppm, decreases, and then falls back to zero after 5 days. The gray curve initially fluctuates with a peak at around 27 ppm, then decreases sharply and then disappears. The curve for 3/4 of the substrate starts slightly higher than all the others, with a peak at around 37 ppm, then decreases considerably and disappears around the ninth day.</p>
        <fig id="fig10">
          <label>Figure 10</label>
          <graphic xlink:href="https://html.scirp.org/file/7302255-rId26.jpeg?20260416025051" />
        </fig>
        <p><bold>Figure 7.</bold> Evolution of hydrogen sulfide content.</p>
        <p><bold>General</bold><bold>Trend</bold><bold>in</bold><bold>Pilot</bold><bold>Biogas</bold><bold>Production</bold></p>
        <p>The evolution of methane (CH<sub>4</sub>) shows a latency period from day 0 to day 1 (<xref ref-type="fig" rid="fig8">Figure 8</xref>). From day 1 to day 3, there is a start-up period for CH<sub>4</sub> production, which increases from 25% to 48%. From day 4 to day 12, the CH<sub>4</sub> content reaches 55% and rises to 59%. From day 13 to day 20, there is a slight decrease in biomethane, which falls to 52%. CO<sub>2</sub> evolves inversely to CH<sub>4</sub>, which is normal with an initial peak at 46% (day 2) due to high acid production. CO<sub>2</sub> then stabilizes between 40% - 44% with a slight increase around day 18 - day 20. The hydrogen sulfide (H<sub>2</sub>S) content is low at the start (0% - 2%). The significant peak occurs around day 8 (~12%).</p>
        <fig id="fig11">
          <label>Figure 11</label>
          <graphic xlink:href="https://html.scirp.org/file/7302255-rId27.jpeg?20260416025051" />
        </fig>
        <p><bold>Figure 8.</bold> Evolution of pilot biogas production.</p>
      </sec>
    </sec>
    <sec id="sec4">
      <title>4. Discussion</title>
      <p>The physicochemical analysis of vegetable waste revealed a volatile dry matter (VDM) content of 78.88%, reflecting a high proportion of biodegradable organic matter, which is essential for good methanogenic potential according to Nikiema [<xref ref-type="bibr" rid="B20">20</xref>] and Deublein and Steinhauser [<xref ref-type="bibr" rid="B21">21</xref>]. The C/N ratio was 5.47, which is below the optimal range of 20 - 30 generally recommended for stable and efficient anaerobic methanogenesis [<xref ref-type="bibr" rid="B22">22</xref>][<xref ref-type="bibr" rid="B23">23</xref>]. Such a low C/N ratio, typical of nitrogen-rich vegetable waste, can potentially lead to an accumulation of ammonia (<inline-formula><mml:math display="inline"><mml:mrow><mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mtext> NH </mml:mtext></mml:mrow><mml:mtext> 3 </mml:mtext></mml:msub></mml:mrow><mml:mo> / </mml:mo><mml:mrow><mml:msubsup><mml:mrow><mml:mtext> NH </mml:mtext></mml:mrow><mml:mtext> 4 </mml:mtext><mml:mtext> + </mml:mtext></mml:msubsup></mml:mrow></mml:mrow></mml:mrow></mml:math></inline-formula> ) in the digester, inhibiting the activity of methanogenic bacteria, particularly at higher pH levels [<xref ref-type="bibr" rid="B24">24</xref>]-[<xref ref-type="bibr" rid="B26">26</xref>]. This result highlights the strategic importance of co-digestion with more carbon-rich substrates such as cattle manure, which was used in our study as inoculum and initial co-substrate to balance this ratio and prevent inhibition [<xref ref-type="bibr" rid="B27">27</xref>]. The lignin content was moderate. Excessive lignin content could have limited biodegradability and hydrolysis rate [<xref ref-type="bibr" rid="B28">28</xref>][<xref ref-type="bibr" rid="B29">29</xref>], but the value obtained is considered acceptable for the process. In summary, the physicochemical parameters showed that vegetable waste can be considered a good candidate for biomethane production.</p>
      <p>The biogas production results show that feeding only cattle manure generated the highest volume of biogas (7.42 dm<sup>3</sup>/day, with a peak of 16 dm<sup>3</sup>). The introduction of vegetable waste led to a decrease in the total volume of biogas produced. This could be explained by the difficulty of anaerobic digestion microorganisms to adapt. According to Taherzadeh and Karimi [<xref ref-type="bibr" rid="B30">30</xref>], anaerobic digestion microorganisms need time to acclimatize to a new substrate. The quality of the biogas in terms of methane content was significantly improved by co-digestion, reaching proportions of 70%, which is much higher than that of manure alone (52.71%). Our results on methane proportions are consistent with those reported in other studies on the methanization of household vegetable waste, which often range between 50% and 70% [<xref ref-type="bibr" rid="B31">31</xref>]-[<xref ref-type="bibr" rid="B33">33</xref>]. This improvement in methane quality, despite a sometimes-lower total volume of biogas, indicates the high intrinsic methanogenic potential of vegetable waste. The decrease in overall biogas volume with the addition of vegetable waste could be partly due to the low C/N ratio of vegetable waste. According to Li <italic>et al</italic>. [<xref ref-type="bibr" rid="B34">34</xref>], the C/N ratio corresponds to the degree of mineralization of organic matter. In fact, the higher the nitrogen content, the lower the ratio and the higher the rate of mineralization. Too low a value leads to an accumulation of ammonia and pH levels exceeding 8.5, which are toxic to methanogenic bacteria. It is already known that optimal anaerobic digestion occurs for C/N ratios between 20 and 30. For higher values, nitrogen consumption is rapid, leading to low biogas production. Furthermore, the change in CO<sub>2</sub> content showed a generally opposite trend to that of methane, which is an expected characteristic of the methanization process [<xref ref-type="bibr" rid="B21">21</xref>]. Successful methanization depends on maintaining stable conditions. </p>
      <p>With regard to the digestate, the pH remained remarkably stable and within a favorable range (6.5 - 7.50) for all feedstocks. This range is considered optimal for the activity of the microbial consortia involved in methanogenesis [<xref ref-type="bibr" rid="B35">35</xref>][<xref ref-type="bibr" rid="B36">36</xref>]. </p>
      <p>The stability of the pH, despite the gradual introduction of vegetable waste that can potentially acidify the environment during acidogenesis, shows a good buffering capacity of the system, probably conferred by the bovine manure inoculum and the production of bicarbonates during anaerobic degradation [<xref ref-type="bibr" rid="B37">37</xref>][<xref ref-type="bibr" rid="B38">38</xref>].</p>
      <p>Volatile fatty acid (VFA) concentrations varied, with the highest value (132 mg/L acetic acid) for the 1/3 substrate feed, decreasing for the 1/2 (84 mg/L) and 3/4 (39.60 mg/L) proportions. Very high VFA levels (&gt;2000 - 3000 mg/L) may indicate an imbalance in the process and inhibition of methanogenesis [<xref ref-type="bibr" rid="B39">39</xref>]-[<xref ref-type="bibr" rid="B41">41</xref>]. The VFA levels observed, coupled with stable pH and better methane production, suggest active hydrolysis and acidogenesis, followed by efficient methanogenesis, particularly for the 1/2 and 3/4 proportions, where VFA levels are lower, indicating good conversion. Franke-Whittle <italic>et al</italic>. [<xref ref-type="bibr" rid="B42">42</xref>] showed that at stable pH, the quality of VFA has more or less impact on methanogenesis: an acetate concentration of 2400 mg/L still has no effect on methanogenic bacteria, while a propionate concentration of 900 mg/L is sufficient to inhibit them in part. Finally, the H<sub>2</sub>S content remained very low for all feeds (maximum peak of 37 ppm for the three-quarter [3/4] feed and highest average of 9 ppm for the same feed). High concentrations of H<sub>2</sub>S (&gt;50 - 100 ppm in biogas) can be corrosive to equipment and toxic to methanogens [<xref ref-type="bibr" rid="B25">25</xref>][<xref ref-type="bibr" rid="B43">43</xref>]. H<sub>2</sub>S gas has a rotten egg smell, detectable by humans from 0.21 ppmv according to Izumi <italic>et al</italic>. [<xref ref-type="bibr" rid="B44">44</xref>]. Prolonged inhalation of H<sub>2</sub>S causes irritation of the mucous membranes of the eyes and respiratory tract, effects on the central nervous system, respiratory and cardiac disorders, and can lead to death [<xref ref-type="bibr" rid="B45">45</xref>][<xref ref-type="bibr" rid="B46">46</xref>]. H<sub>2</sub>S is also corrosive to most metals and can therefore damage biogas recovery equipment. H<sub>2</sub>S must therefore not be released into the atmosphere. However, this is very rarely the case because biogas undergoes combustion in order to be recovered. During combustion, H<sub>2</sub>S is oxidized to form sulfur dioxide (SO<sub>2</sub>), which is also toxic. According to Panza and Belgiorno [<xref ref-type="bibr" rid="B47">47</xref>], engines are more sensitive than turbines to H<sub>2</sub>S, whose concentration must not exceed 500 ppmv, or even 50 ppmv depending on the type. The low levels observed are therefore a major advantage for future exploitation of the biogas produced. </p>
      <p>The overall evolution of biogas production using this technology shows a latency period from D0 to D1 for biomethane (CH<sub>4</sub>). From D1 to D3, there is a start-up period for CH<sub>4</sub> production, which increases from 25% to 48%. This indicates a gradual establishment of methanogenic bacteria in the biodigester. The digester leaves the strictly acidogenic phase and stabilizes after 4 days. According to Elasri and El Afilal [<xref ref-type="bibr" rid="B48">48</xref>], anaerobic digestion occurs in 4 stages, the first of which is the hydrolysis of organic matter such as proteins, fats, cellulose, and starch. This stage releases monomers such as amino acids, fatty acids, and simple sugars. These monomers are converted into a mixture of lactic acid, butyric acid, etc., and neutral compounds (ethanol) by acidogenic bacteria, thus acidifying the digester. Stabilization occurs when the various acids and other products from the previous stage are converted into methane precursors such as acetic acid, carbon dioxide (CO<sub>2</sub>), and hydrogen (H<sub>2</sub>). This is the work of acetogenic bacteria. From D4 to D12, the CH<sub>4</sub> content reaches 55% and rises to 59%. A period of stabilization of the digester is observed, with a level typical of a digester in good working order with dominant methanogenic activity. In this phase, methanogenic bacteria use the precursors formed in the previous stages to produce methane. The four stages take place simultaneously in the digester, with a balancé being established between the stages. From D13 to D20, there is a slight decrease in biomethane, which falls to 52%. This imbalance is thought to be due to substrate depletion. The lack of renewal leads to the end of production between the 21st and 24th day. This shows the need for continuous feeding of the digester, especially from the 12th day onwards, when an equilibrium is observed in the digester with a biomethane content reaching 59%.</p>
      <p>CO<sub>2</sub> evolves inversely to CH<sub>4</sub>, which is normal with an initial peak at 46% (day 2) due to high acid production. CO<sub>2</sub> then stabilizes between 40% - 44% with a slight increase around D18 - D20. This result is consistent with the work of Nikiema <italic>et al</italic>. [<xref ref-type="bibr" rid="B49">49</xref>], as at the start of anaerobic digestion, organic matter is broken down with the release of large amounts of CO<sub>2</sub>. As methanization progresses, CO<sub>2</sub> is consumed and used in the production of CH<sub>4</sub> via the hydrogenotrophic pathway. The hydrogen sulfide (H<sub>2</sub>S) content is low at the outset (0% - 2%). The peak occurs around day 8 (~12%), indicating the degradation of sulfur-rich materials (proteins, food waste) and high activity of sulfate-reducing bacteria. A rapid drop was observed after day 9, close to 0%. This is a very good sign, indicating a balanced system, as the available sulfur has been consumed. The methanogens have regained the upper hand.</p>
    </sec>
    <sec id="sec5">
      <title>5. Conclusion</title>
      <p>This study addressed the issue of energy self-sufficiency among households in the peri-urban areas of Ouagadougou. The results confirm that vegetable waste could be an ideal substrate for biogas production, given its availability in our study area. However, this waste has a low C/N ratio (5.47), which proved to be a constraint for optimal volumetric production. The experiment showed that while cattle manure alone produced a higher volume of biogas, co-digestion with vegetable waste improved the quality of the gas, with a methane content reaching 58.41% (compared to 52.71% for manure alone), validating the hypothesis that biogas produced from vegetable waste has a high methane content. The biogas production technology proved to be biologically stable, efficient, and well-balanced. Methane levels reached values typical of an optimally functioning digester, confirming effective conversion of organic matter into biogas. The temporary rise in H<sub>2</sub>S and its subsequent decline further demonstrate a healthy microbial succession and system recovery. The reduction in methane after day 12 highlights the need for continuous or periodic feeding to maintain performance. Therefore, the technology is technically reliable, but its long-term productivity depends on proper operational management, particularly substrate supply.</p>
    </sec>
    <sec id="sec6">
      <title>Acknowledgements</title>
      <p>The authors thank the Albert Schweitzer International Centre (CEAS) for technical support in carrying out this study. </p>
    </sec>
    <sec id="sec7">
      <title>Funding</title>
      <p>This article was supported by funding from New Dawn University. </p>
    </sec>
  </body>
  <back>
    <ref-list>
      <title>References</title>
      <ref id="B1">
        <label>1.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Institut National de la Statistique et de la Démographie (INSD) (2021) Enquête démographique et de santé du Burkina Faso 2021.</mixed-citation>
          <element-citation publication-type="other">
            <year>2021</year>
            <article-title>Enquête démographique et de santé du Burkina Faso 2021</article-title>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B2">
        <label>2.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Korahire, F. (2014) Caractérisation physico-chimique et évaluation du potentiel de compostage et de méthanisation des déchets solides ménagers de la ville de Ouagadougou. Thèse de Doctorat, Université de Ouagadougou/Université de Limoges.</mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Korahire, F.</string-name>
              <string-name>Doctorat, U</string-name>
            </person-group>
            <year>2014</year>
            <article-title>Caractérisation physico-chimique et évaluation du potentiel de compostage et de méthanisation des déchets solides ménagers de la ville de Ouagadougou</article-title>
            <source>Thèse de Doctorat</source>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B3">
        <label>3.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Agence de la Transition Écologique (2021) Chiffres clés des déchets-édition 2021. Agence de la Transition Écologique.</mixed-citation>
          <element-citation publication-type="other">
            <year>2021</year>
            <article-title>Chiffres clés des déchets-édition 2021</article-title>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B4">
        <label>4.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Chanakya, H.N., Ramachandra, T.V., Guruprasad, M. and Devi, V. (2007) Micro-treatment Options for Components of Organic Fraction of MSW in Residential Areas. <italic>Environmental</italic><italic>Monitoring</italic><italic>and</italic><italic>Assessment</italic>, 135, 129-139. https://doi.org/10.1007/s10661-007-9711-5 <pub-id pub-id-type="doi">10.1007/s10661-007-9711-5</pub-id><pub-id pub-id-type="pmid">17503210</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1007/s10661-007-9711-5">https://doi.org/10.1007/s10661-007-9711-5</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Chanakya, H.N.</string-name>
              <string-name>Ramachandra, T.V.</string-name>
              <string-name>Guruprasad, M.</string-name>
              <string-name>Devi, V.</string-name>
            </person-group>
            <year>2007</year>
            <article-title>Micro-treatment Options for Components of Organic Fraction of MSW in Residential Areas</article-title>
            <source>Environmental Monitoring and Assessment</source>
            <volume>135</volume>
            <pub-id pub-id-type="doi">10.1007/s10661-007-9711-5</pub-id>
            <pub-id pub-id-type="pmid">17503210</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B5">
        <label>5.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Bougma, P.C., Bondé, L., Yaro, V.S.O., Dicko, I., Zongo, A.F.R., Gebremichael, A.W., <italic>et al</italic>. (2025) Greenhouse Gas Emissions from Fertilization Practices in Maize Cropping in Sub-Saharan Africa: Toward Climate-Smart Agriculture. <italic>Environments</italic>, 12, Article 211. https://doi.org/10.3390/environments12070211 <pub-id pub-id-type="doi">10.3390/environments12070211</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.3390/environments12070211">https://doi.org/10.3390/environments12070211</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Bougma, P.C.</string-name>
              <string-name>Yaro, V.S.O.</string-name>
              <string-name>Dicko, I.</string-name>
              <string-name>Zongo, A.F.R.</string-name>
              <string-name>Gebremichael, A.W.</string-name>
            </person-group>
            <year>2025</year>
            <article-title>Greenhouse Gas Emissions from Fertilization Practices in Maize Cropping in Sub-Saharan Africa: Toward Climate-Smart Agriculture</article-title>
            <source>Environments</source>
            <volume>12</volume>
            <elocation-id>211</elocation-id>
            <pub-id pub-id-type="doi">10.3390/environments12070211</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B6">
        <label>6.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Chitou, S.M. and Gbandey, G.T. (2020) Atlas de l’énergie dans l’espace UEMOA-rapport 2020. L’Institut de la Francophonie pour le développement durable (IFDD), 156.</mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Chitou, S.M.</string-name>
              <string-name>Gbandey, G.T.</string-name>
            </person-group>
            <year>2020</year>
            <article-title>Atlas de l’énergie dans l’espace UEMOA-rapport 2020</article-title>
            <source>L’Institut de la Francophonie pour le développement durable (IFDD)</source>
            <volume>156</volume>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B7">
        <label>7.</label>
        <citation-alternatives>
          <mixed-citation publication-type="confproc">Marien, J.N., Bertrand, A., Toit, B.D., Gautier, D., Gazull, L., Idowu, M., Kassambara, A., Mallet, B., Montagne, P., Nkoua, M., Ramamonjisoa, B. and Swart, J. (2008) <italic>Foresterie urbaine et périurbaine en Afrique,</italic><italic>Quelles</italic><italic>perspectives pour le bois énergie?</italic> FAO Conference, Urban and Periurban Forestry (UPF), 92 p.</mixed-citation>
          <element-citation publication-type="confproc">
            <person-group person-group-type="author">
              <string-name>Marien, J.N.</string-name>
              <string-name>Bertrand, A.</string-name>
              <string-name>Toit, B.D.</string-name>
              <string-name>Gautier, D.</string-name>
              <string-name>Gazull, L.</string-name>
              <string-name>Idowu, M.</string-name>
              <string-name>Kassambara, A.</string-name>
              <string-name>Mallet, B.</string-name>
              <string-name>Montagne, P.</string-name>
              <string-name>Nkoua, M.</string-name>
              <string-name>Ramamonjisoa, B.</string-name>
              <string-name>Swart, J.</string-name>
              <string-name>Afrique, Q</string-name>
              <string-name>Conference, U</string-name>
            </person-group>
            <year>2008</year>
            <article-title>Foresterie urbaine et périurbaine en Afrique, Quelles perspectives pour le bois énergie? FAO Conference, Urban and Periurban Forestry (UPF), 92 p</article-title>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B8">
        <label>8.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Gustavsson, J., Cederberg, C., Sonesson, U., van Otterdijk, R. and Meybeck, A. (2011) Global Food Losses and Food Waste: Extent, Causes and Prevention. Food and Agriculture Organization of the United Nations (FAO).</mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Gustavsson, J.</string-name>
              <string-name>Cederberg, C.</string-name>
              <string-name>Sonesson, U.</string-name>
              <string-name>Otterdijk, R.</string-name>
              <string-name>Meybeck, A.</string-name>
              <string-name>Extent, C</string-name>
            </person-group>
            <year>2011</year>
            <article-title>Global Food Losses and Food Waste: Extent, Causes and Prevention</article-title>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B9">
        <label>9.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Bouzid, A., Benabdeli, K. and Bouzid, K. (2019) Essai de valorisation des déchets verts de cuisine comme ingrédients pour améliorer la qualité nutritionnelle d’aliments de gallinacés et d’herbivores dans la ville de Mascara (Algérie). <italic>Environnement</italic>, <italic>Ingénierie</italic><italic>&amp;</italic><italic>Développement</italic>, 82, 35-40. https://doi.org/10.4267/dechets-sciences-techniques.4196 <pub-id pub-id-type="doi">10.4267/dechets-sciences-techniques.4196</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.4267/dechets-sciences-techniques.4196">https://doi.org/10.4267/dechets-sciences-techniques.4196</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Bouzid, A.</string-name>
              <string-name>Benabdeli, K.</string-name>
              <string-name>Bouzid, K.</string-name>
              <string-name>Environnement, I</string-name>
            </person-group>
            <year>2019</year>
            <article-title>Essai de valorisation des déchets verts de cuisine comme ingrédients pour améliorer la qualité nutritionnelle d’aliments de gallinacés et d’herbivores dans la ville de Mascara (Algérie)</article-title>
            <source>Environnement</source>
            <volume>82</volume>
            <pub-id pub-id-type="doi">10.4267/dechets-sciences-techniques.4196</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B10">
        <label>10.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Ahring, B.K. and Westermann, P. (1988) Product Inhibition of Butyrate Metabolism by Acetate and Hydrogen in a Thermophilic Coculture. <italic>Applied</italic><italic>and</italic><italic>Environmental</italic><italic>Microbiology</italic>, 54, 2393-2397. https://doi.org/10.1128/aem.54.10.2393-2397.1988 <pub-id pub-id-type="doi">10.1128/aem.54.10.2393-2397.1988</pub-id><pub-id pub-id-type="pmid">16347751</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1128/aem.54.10.2393-2397.1988">https://doi.org/10.1128/aem.54.10.2393-2397.1988</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Ahring, B.K.</string-name>
              <string-name>Westermann, P.</string-name>
            </person-group>
            <year>1988</year>
            <article-title>Product Inhibition of Butyrate Metabolism by Acetate and Hydrogen in a Thermophilic Coculture</article-title>
            <source>Applied and Environmental Microbiology</source>
            <volume>54</volume>
            <pub-id pub-id-type="doi">10.1128/aem.54.10.2393-2397.1988</pub-id>
            <pub-id pub-id-type="pmid">16347751</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B11">
        <label>11.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Mosier, N., Wyman, C., Dale, B., Elander, R., Lee, Y.Y., Holtzapple, M. and Ladisch, M. (2005) Features of Promising Technologies for Pretreatment of Lignocellulosic Biomass. <italic>Bioresource</italic><italic>Technology</italic>, 96, 673-686. https://doi.org/10.1016/j.biortech.2004.06.025 <pub-id pub-id-type="doi">10.1016/j.biortech.2004.06.025</pub-id><pub-id pub-id-type="pmid">15588770</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/j.biortech.2004.06.025">https://doi.org/10.1016/j.biortech.2004.06.025</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Mosier, N.</string-name>
              <string-name>Wyman, C.</string-name>
              <string-name>Dale, B.</string-name>
              <string-name>Elander, R.</string-name>
              <string-name>Lee, Y.Y.</string-name>
              <string-name>Holtzapple, M.</string-name>
              <string-name>Ladisch, M.</string-name>
            </person-group>
            <year>2005</year>
            <article-title>Features of Promising Technologies for Pretreatment of Lignocellulosic Biomass</article-title>
            <source>Bioresource Technology</source>
            <volume>96</volume>
            <pub-id pub-id-type="doi">10.1016/j.biortech.2004.06.025</pub-id>
            <pub-id pub-id-type="pmid">15588770</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B12">
        <label>12.</label>
        <citation-alternatives>
          <mixed-citation publication-type="journal">Traoré, D., Dianou, D. and Traoré, A. (2017) Biomethane Potential of Some Agroresources in Burkina Faso: Case Study of Vegetable Residues, Pig Manure, Mango Waste and Bovine Manure. <italic>Journal</italic><italic>of</italic><italic>Advances</italic><italic>in</italic><italic>Biology</italic><italic>&amp;</italic><italic>Biotechnology</italic>, 15, 1-11. https://doi.org/10.9734/jabb/2017/36775 <pub-id pub-id-type="doi">10.9734/jabb/2017/36775</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.9734/jabb/2017/36775">https://doi.org/10.9734/jabb/2017/36775</ext-link></mixed-citation>
          <element-citation publication-type="journal">
            <person-group person-group-type="author">
              <string-name>Dianou, D.</string-name>
              <string-name>Residues, P</string-name>
              <string-name>Manure, M</string-name>
            </person-group>
            <year>2017</year>
            <article-title>Biomethane Potential of Some Agroresources in Burkina Faso: Case Study of Vegetable Residues, Pig Manure, Mango Waste and Bovine Manure</article-title>
            <source>Journal of Advances in Biology &amp; Biotechnology</source>
            <volume>15</volume>
            <pub-id pub-id-type="doi">10.9734/jabb/2017/36775</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B13">
        <label>13.</label>
        <citation-alternatives>
          <mixed-citation publication-type="journal">Makaya, J.M., Nikiema, M., Ouéda, N., Kouhounde, S.H.S. and Somda, M.K. (2025) Optimization of Biomethane Production from Vegetable Waste Collected in Ouagadougou Markets and “Yaars” Using the Response Surface Method (RSM). <italic>Journal</italic><italic>of</italic><italic>Environmental</italic><italic>Protection</italic>, 16, 273-291. https://doi.org/10.4236/jep.2025.164014 <pub-id pub-id-type="doi">10.4236/jep.2025.164014</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.4236/jep.2025.164014">https://doi.org/10.4236/jep.2025.164014</ext-link></mixed-citation>
          <element-citation publication-type="journal">
            <person-group person-group-type="author">
              <string-name>Makaya, J.M.</string-name>
              <string-name>Nikiema, M.</string-name>
              <string-name>Kouhounde, S.H.S.</string-name>
              <string-name>Somda, M.K.</string-name>
            </person-group>
            <year>2025</year>
            <article-title>Optimization of Biomethane Production from Vegetable Waste Collected in Ouagadougou Markets and “Yaars” Using the Response Surface Method (RSM)</article-title>
            <source>Journal of Environmental Protection</source>
            <volume>16</volume>
            <pub-id pub-id-type="doi">10.4236/jep.2025.164014</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B14">
        <label>14.</label>
        <citation-alternatives>
          <mixed-citation publication-type="journal">Nout, M.J.R., Rombouts, F.M. and Havelaar, A. (1989) Effect of Accelerated Natural Lactic Fermentation of Infant Good Ingredients on Some Pathogenic Microorganisms. <italic>International</italic><italic>Journal</italic><italic>of</italic><italic>Food</italic><italic>Microbiology</italic>, 8, 351-361. https://doi.org/10.1016/0168-1605(89)90006-8 <pub-id pub-id-type="doi">10.1016/0168-1605(89)90006-8</pub-id><pub-id pub-id-type="pmid">2701696</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/0168-1605(89)90006-8">https://doi.org/10.1016/0168-1605(89)90006-8</ext-link></mixed-citation>
          <element-citation publication-type="journal">
            <person-group person-group-type="author">
              <string-name>Nout, M.J.R.</string-name>
              <string-name>Rombouts, F.M.</string-name>
              <string-name>Havelaar, A.</string-name>
            </person-group>
            <year>1989</year>
            <article-title>Effect of Accelerated Natural Lactic Fermentation of Infant Good Ingredients on Some Pathogenic Microorganisms</article-title>
            <source>International Journal of Food Microbiology</source>
            <volume>1605</volume>
            <issue>89</issue>
            <pub-id pub-id-type="doi">10.1016/0168-1605(89)90006-8</pub-id>
            <pub-id pub-id-type="pmid">2701696</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B15">
        <label>15.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Allison, L.E. (1965) Carbone Organique. In: Black, C.A., Evans, D.D., White, J.L., Ensiminger, L.E. and Clark, F.E., Eds., <italic>Méthodes</italic><italic>d</italic>’ <italic>Analyse</italic><italic>des Sols</italic>, American Society of Agronomy, 1367-1378.</mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Allison, L.E.</string-name>
              <string-name>Black, C.A.</string-name>
              <string-name>Evans, D.D.</string-name>
              <string-name>White, J.L.</string-name>
              <string-name>Ensiminger, L.E.</string-name>
              <string-name>Clark, F.E.</string-name>
              <string-name>Sols, A</string-name>
            </person-group>
            <year>1965</year>
            <article-title>Carbone Organique</article-title>
            <source>In: Black</source>
            <volume>1367</volume>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B16">
        <label>16.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">TAPPI (Technical Association of the Pulp and Paper Industry) (2002) Ash in Wood and Pulp. T211 CM-86.</mixed-citation>
          <element-citation publication-type="other">
            <year>2002</year>
            <article-title>Ash in Wood and Pulp</article-title>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B17">
        <label>17.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">DuBois, M., Gilles, K.A., Hamilton, J.K., Rebers, P.A. and Smith, F. (1956) Colorimetric Method for Determination of Sugars and Related Substances. <italic>Analytical Chemistry</italic>, 28, 350-356. https://doi.org/10.1021/ac60111a017 <pub-id pub-id-type="doi">10.1021/ac60111a017</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1021/ac60111a017">https://doi.org/10.1021/ac60111a017</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>DuBois, M.</string-name>
              <string-name>Gilles, K.A.</string-name>
              <string-name>Hamilton, J.K.</string-name>
              <string-name>Rebers, P.A.</string-name>
              <string-name>Smith, F.</string-name>
            </person-group>
            <year>1956</year>
            <article-title>Colorimetric Method for Determination of Sugars and Related Substances</article-title>
            <source>Analytical Chemistry</source>
            <volume>28</volume>
            <pub-id pub-id-type="doi">10.1021/ac60111a017</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B18">
        <label>18.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Kotsyurbenko, O.R., Glagolev, M.V., Nozhevnikova, A.N. and Conrad, R. (2001) Competition between Homoacetogenic Bacteria and Methanogenic Archaea for Hydrogen at Low Temperature. <italic>FEMS</italic><italic>Microbiology</italic><italic>Ecology</italic>, 38, 153-159. https://doi.org/10.1111/j.1574-6941.2001.tb00893.x <pub-id pub-id-type="doi">10.1111/j.1574-6941.2001.tb00893.x</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1111/j.1574-6941.2001.tb00893.x">https://doi.org/10.1111/j.1574-6941.2001.tb00893.x</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Kotsyurbenko, O.R.</string-name>
              <string-name>Glagolev, M.V.</string-name>
              <string-name>Nozhevnikova, A.N.</string-name>
              <string-name>Conrad, R.</string-name>
            </person-group>
            <year>2001</year>
            <article-title>Competition between Homoacetogenic Bacteria and Methanogenic Archaea for Hydrogen at Low Temperature</article-title>
            <source>FEMS Microbiology Ecology</source>
            <volume>38</volume>
            <pub-id pub-id-type="doi">10.1111/j.1574-6941.2001.tb00893.x</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B19">
        <label>19.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Simankova, M.V., Kotsyurbenko, O.R., Lueders, T., Nozhevnikova, A.N., Wagner, B., Conrad, R., <italic>et al</italic>. (2003) Isolation and Characterization of New Strains of Methanogens from Cold Terrestrial Habitats. <italic>Systematic</italic><italic>and</italic><italic>Applied</italic><italic>Microbiology</italic>, 26, 312-318. https://doi.org/10.1078/072320203322346173 <pub-id pub-id-type="doi">10.1078/072320203322346173</pub-id><pub-id pub-id-type="pmid">12866859</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1078/072320203322346173">https://doi.org/10.1078/072320203322346173</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Simankova, M.V.</string-name>
              <string-name>Kotsyurbenko, O.R.</string-name>
              <string-name>Lueders, T.</string-name>
              <string-name>Nozhevnikova, A.N.</string-name>
              <string-name>Wagner, B.</string-name>
              <string-name>Conrad, R.</string-name>
            </person-group>
            <year>2003</year>
            <article-title>Isolation and Characterization of New Strains of Methanogens from Cold Terrestrial Habitats</article-title>
            <source>Systematic and Applied Microbiology</source>
            <volume>26</volume>
            <pub-id pub-id-type="doi">10.1078/072320203322346173</pub-id>
            <pub-id pub-id-type="pmid">12866859</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B20">
        <label>20.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Nikiema, M. (2015) Valorisation des déchets organiques solides municipaux par la voie de la méthanisation au Burkina Faso, Thèse de Doctorat, Université Pr Joseph KI-ZERBO, 250 p.</mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Nikiema, M.</string-name>
              <string-name>Faso, T</string-name>
              <string-name>Doctorat, U</string-name>
            </person-group>
            <year>2015</year>
            <article-title>Valorisation des déchets organiques solides municipaux par la voie de la méthanisation au Burkina Faso, Thèse de Doctorat, Université Pr Joseph KI-ZERBO, 250 p</article-title>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B21">
        <label>21.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Deublein, D. and Steinhauser, A. (2008) Biogas from Waste and Renewable Resources: An Introduction. Wiley-VCH, 1-443.</mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Deublein, D.</string-name>
              <string-name>Steinhauser, A.</string-name>
            </person-group>
            <year>2008</year>
            <article-title>Biogas from Waste and Renewable Resources: An Introduction</article-title>
            <source>Wiley-VCH</source>
            <volume>1</volume>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B22">
        <label>22.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Yadvika, S., Sreekrishnan, T.R., Kohli, S. and Rana, V. (2004) Enhancement of Biogas Production from Solid Substrates Using Different Techniques—A Review. <italic>Bioresource</italic><italic>Technology</italic>, 95, 1-10. https://doi.org/10.1016/j.biortech.2004.02.010 <pub-id pub-id-type="doi">10.1016/j.biortech.2004.02.010</pub-id><pub-id pub-id-type="pmid">15207286</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/j.biortech.2004.02.010">https://doi.org/10.1016/j.biortech.2004.02.010</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Yadvika, S.</string-name>
              <string-name>Sreekrishnan, T.R.</string-name>
              <string-name>Kohli, S.</string-name>
              <string-name>Rana, V.</string-name>
            </person-group>
            <year>2004</year>
            <article-title>Enhancement of Biogas Production from Solid Substrates Using Different Techniques—A Review</article-title>
            <source>Bioresource Technology</source>
            <volume>95</volume>
            <pub-id pub-id-type="doi">10.1016/j.biortech.2004.02.010</pub-id>
            <pub-id pub-id-type="pmid">15207286</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B23">
        <label>23.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Gerardi, M.H. (2003) The Microbiology of Anaerobic Digesters. Wiley. https://doi.org/10.1002/0471468967 <pub-id pub-id-type="doi">10.1002/0471468967</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1002/0471468967">https://doi.org/10.1002/0471468967</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Gerardi, M.H.</string-name>
            </person-group>
            <year>2003</year>
            <article-title>The Microbiology of Anaerobic Digesters</article-title>
            <pub-id pub-id-type="doi">10.1002/0471468967</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B24">
        <label>24.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Gunaseelan, V.N. (2004) Biochemical Methane Potential of Fruits and Vegetable Solid Waste Feedstocks. <italic>Biomass</italic><italic>and</italic><italic>Bioenergy</italic>, 26, 389-399. https://doi.org/10.1016/j.biombioe.2003.08.006 <pub-id pub-id-type="doi">10.1016/j.biombioe.2003.08.006</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/j.biombioe.2003.08.006">https://doi.org/10.1016/j.biombioe.2003.08.006</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Gunaseelan, V.N.</string-name>
            </person-group>
            <year>2004</year>
            <article-title>Biochemical Methane Potential of Fruits and Vegetable Solid Waste Feedstocks</article-title>
            <source>Biomass and Bioenergy</source>
            <volume>26</volume>
            <pub-id pub-id-type="doi">10.1016/j.biombioe.2003.08.006</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B25">
        <label>25.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Kayhanian, M. (1999) Ammonia Inhibition in High-Solids Biogasification: An Overview and Practical Solutions. <italic>Environmental</italic><italic>Technology</italic>, 20, 355-365. https://doi.org/10.1080/09593332008616828 <pub-id pub-id-type="doi">10.1080/09593332008616828</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1080/09593332008616828">https://doi.org/10.1080/09593332008616828</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Kayhanian, M.</string-name>
            </person-group>
            <year>1999</year>
            <article-title>Ammonia Inhibition in High-Solids Biogasification: An Overview and Practical Solutions</article-title>
            <source>Environmental Technology</source>
            <volume>20</volume>
            <pub-id pub-id-type="doi">10.1080/09593332008616828</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B26">
        <label>26.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Chen, Y., Cheng, J.J. and Creamer, K.S. (2008) Inhibition of Anaerobic Digestion Process: A Review. <italic>Bioresource</italic><italic>Technology</italic>, 99, 4044-4064. https://doi.org/10.1016/j.biortech.2007.01.057 <pub-id pub-id-type="doi">10.1016/j.biortech.2007.01.057</pub-id><pub-id pub-id-type="pmid">17399981</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/j.biortech.2007.01.057">https://doi.org/10.1016/j.biortech.2007.01.057</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Chen, Y.</string-name>
              <string-name>Cheng, J.J.</string-name>
              <string-name>Creamer, K.S.</string-name>
            </person-group>
            <year>2008</year>
            <article-title>Inhibition of Anaerobic Digestion Process: A Review</article-title>
            <source>Bioresource Technology</source>
            <volume>99</volume>
            <pub-id pub-id-type="doi">10.1016/j.biortech.2007.01.057</pub-id>
            <pub-id pub-id-type="pmid">17399981</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B27">
        <label>27.</label>
        <citation-alternatives>
          <mixed-citation publication-type="journal">Zeshan and Karthikeyan, O.P. (2012) Effect of C/N Ratio and pH on the Anaerobic Co-Digestion of Fruit and Vegetable Waste and Poultry Waste. <italic>International Journal of Environmental Science and Development</italic>, 3, 145-149.</mixed-citation>
          <element-citation publication-type="journal">
            <person-group person-group-type="author">
              <string-name>Karthikeyan, O.P.</string-name>
            </person-group>
            <year>2012</year>
            <article-title>Effect of C/N Ratio and pH on the Anaerobic Co-Digestion of Fruit and Vegetable Waste and Poultry Waste</article-title>
            <source>International Journal of Environmental Science and Development</source>
            <volume>3</volume>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B28">
        <label>28.</label>
        <citation-alternatives>
          <mixed-citation publication-type="journal">Mata-Alvarez, J., Macé, S. and Llabrés, P. (2000) Anaerobic Digestion of Organic Solid Wastes. An Overview of Research Achievements and Perspectives. <italic>Bioresource</italic><italic>Technology</italic>, 74, 3-16. https://doi.org/10.1016/s0960-8524(00)00023-7 <pub-id pub-id-type="doi">10.1016/s0960-8524(00)00023-7</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/s0960-8524(00)00023-7">https://doi.org/10.1016/s0960-8524(00)00023-7</ext-link></mixed-citation>
          <element-citation publication-type="journal">
            <person-group person-group-type="author">
              <string-name>Mata-Alvarez, J.</string-name>
            </person-group>
            <year>2000</year>
            <article-title>Anaerobic Digestion of Organic Solid Wastes</article-title>
            <source>An Overview of Research Achievements and Perspectives. Bioresource Technology</source>
            <volume>8524</volume>
            <issue>00</issue>
            <pub-id pub-id-type="doi">10.1016/s0960-8524(00)00023-7</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B29">
        <label>29.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Monlau, F., Barakat, A., Trably, E., Dumas, C., Steyer, J. and Carrère, H. (2013) Lignocellulosic Materials into Biohydrogen and Biomethane: Impact of Structural Features and Pretreatment. <italic>Critical</italic><italic>Reviews</italic><italic>in</italic><italic>Environmental</italic><italic>Science</italic><italic>and</italic><italic>Technology</italic>, 43, 260-322. https://doi.org/10.1080/10643389.2011.604258 <pub-id pub-id-type="doi">10.1080/10643389.2011.604258</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1080/10643389.2011.604258">https://doi.org/10.1080/10643389.2011.604258</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Monlau, F.</string-name>
              <string-name>Barakat, A.</string-name>
              <string-name>Trably, E.</string-name>
              <string-name>Dumas, C.</string-name>
              <string-name>Steyer, J.</string-name>
            </person-group>
            <year>2013</year>
            <article-title>Lignocellulosic Materials into Biohydrogen and Biomethane: Impact of Structural Features and Pretreatment</article-title>
            <source>Critical Reviews in Environmental Science and Technology</source>
            <volume>43</volume>
            <pub-id pub-id-type="doi">10.1080/10643389.2011.604258</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B30">
        <label>30.</label>
        <citation-alternatives>
          <mixed-citation publication-type="journal">Taherzadeh, M.J. and Karimi, K. (2008) Pretreatment of Lignocellulosic Wastes to Improve Ethanol and Biogas Production: A Review. <italic>International</italic><italic>Journal</italic><italic>of</italic><italic>Molecular</italic><italic>Sciences</italic>, 9, 1621-1651. https://doi.org/10.3390/ijms9091621 <pub-id pub-id-type="doi">10.3390/ijms9091621</pub-id><pub-id pub-id-type="pmid">19325822</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.3390/ijms9091621">https://doi.org/10.3390/ijms9091621</ext-link></mixed-citation>
          <element-citation publication-type="journal">
            <person-group person-group-type="author">
              <string-name>Taherzadeh, M.J.</string-name>
              <string-name>Karimi, K.</string-name>
            </person-group>
            <year>2008</year>
            <article-title>Pretreatment of Lignocellulosic Wastes to Improve Ethanol and Biogas Production: A Review</article-title>
            <source>International Journal of Molecular Sciences</source>
            <volume>9</volume>
            <pub-id pub-id-type="doi">10.3390/ijms9091621</pub-id>
            <pub-id pub-id-type="pmid">19325822</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B31">
        <label>31.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Du, J., Yin, Q., Zhou, X., Guo, Q. and Wu, G. (2022) Distribution of Extracellular Amino Acids and Their Potential Functions in Microbial Cross-Feeding in Anaerobic Digestion Systems. <italic>Bioresource</italic><italic>Technology</italic>, 360, Article 127535. https://doi.org/10.1016/j.biortech.2022.127535 <pub-id pub-id-type="doi">10.1016/j.biortech.2022.127535</pub-id><pub-id pub-id-type="pmid">35779747</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/j.biortech.2022.127535">https://doi.org/10.1016/j.biortech.2022.127535</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Du, J.</string-name>
              <string-name>Yin, Q.</string-name>
              <string-name>Zhou, X.</string-name>
              <string-name>Guo, Q.</string-name>
              <string-name>Wu, G.</string-name>
            </person-group>
            <year>2022</year>
            <article-title>Distribution of Extracellular Amino Acids and Their Potential Functions in Microbial Cross-Feeding in Anaerobic Digestion Systems</article-title>
            <source>Bioresource Technology</source>
            <volume>360</volume>
            <elocation-id>127535</elocation-id>
            <pub-id pub-id-type="doi">10.1016/j.biortech.2022.127535</pub-id>
            <pub-id pub-id-type="pmid">35779747</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B32">
        <label>32.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Weiland, P. (2009) Biogas Production: Current State and Perspectives. <italic>Applied</italic><italic>Microbiology</italic><italic>and</italic><italic>Biotechnology</italic>, 85, 849-860. https://doi.org/10.1007/s00253-009-2246-7 <pub-id pub-id-type="doi">10.1007/s00253-009-2246-7</pub-id><pub-id pub-id-type="pmid">19777226</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1007/s00253-009-2246-7">https://doi.org/10.1007/s00253-009-2246-7</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Weiland, P.</string-name>
            </person-group>
            <year>2009</year>
            <article-title>Biogas Production: Current State and Perspectives</article-title>
            <source>Applied Microbiology and Biotechnology</source>
            <volume>85</volume>
            <pub-id pub-id-type="doi">10.1007/s00253-009-2246-7</pub-id>
            <pub-id pub-id-type="pmid">19777226</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B33">
        <label>33.</label>
        <citation-alternatives>
          <mixed-citation publication-type="web">Adeossi, F.G.F. (2013) Caractérisation du biogaz produit à partir des substrats bovins et porcins dans la région du centre du Burkina Faso. Mémoire de Maîtrise, 44 p. http://documentation.2ie-edu.org/cdi2ie/opac_css/doc_num.php?explnum_id=1824</mixed-citation>
          <element-citation publication-type="web">
            <person-group person-group-type="author">
              <string-name>Adeossi, F.G.F.</string-name>
            </person-group>
            <year>2013</year>
            <article-title>Caractérisation du biogaz produit à partir des substrats bovins et porcins dans la région du centre du Burkina Faso</article-title>
            <source>Mémoire de Maîtrise</source>
            <volume>44</volume>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B34">
        <label>34.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Li, T., Mazéas, L., Sghir, A., Leblon, G. and Bouchez, T. (2009) Insights into Networks of Functional Microbes Catalysing Methanization of Cellulose under Mesophilic Conditions. <italic>Environmental</italic><italic>Microbiology</italic>, 11, 889-904. https://doi.org/10.1111/j.1462-2920.2008.01810.x <pub-id pub-id-type="doi">10.1111/j.1462-2920.2008.01810.x</pub-id><pub-id pub-id-type="pmid">19128320</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1111/j.1462-2920.2008.01810.x">https://doi.org/10.1111/j.1462-2920.2008.01810.x</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Li, T.</string-name>
              <string-name>Sghir, A.</string-name>
              <string-name>Leblon, G.</string-name>
              <string-name>Bouchez, T.</string-name>
            </person-group>
            <year>2009</year>
            <article-title>Insights into Networks of Functional Microbes Catalysing Methanization of Cellulose under Mesophilic Conditions</article-title>
            <source>Environmental Microbiology</source>
            <volume>11</volume>
            <pub-id pub-id-type="doi">10.1111/j.1462-2920.2008.01810.x</pub-id>
            <pub-id pub-id-type="pmid">19128320</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B35">
        <label>35.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Drhimer, F., Rahmani, M., Regraguy, B., El Hajjaji, S., Mabrouki, J., Amrane, A., <italic>et al</italic>. (2023) Treatment of a Food Industry Dye, Brilliant Blue, at Low Concentration Using a New Photocatalytic Configuration. <italic>Sustainability</italic>, 15, Article 5788. https://doi.org/10.3390/su15075788 <pub-id pub-id-type="doi">10.3390/su15075788</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.3390/su15075788">https://doi.org/10.3390/su15075788</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Drhimer, F.</string-name>
              <string-name>Rahmani, M.</string-name>
              <string-name>Regraguy, B.</string-name>
              <string-name>Hajjaji, S.</string-name>
              <string-name>Mabrouki, J.</string-name>
              <string-name>Amrane, A.</string-name>
              <string-name>Dye, B</string-name>
            </person-group>
            <year>2023</year>
            <article-title>Treatment of a Food Industry Dye, Brilliant Blue, at Low Concentration Using a New Photocatalytic Configuration</article-title>
            <source>Sustainability</source>
            <volume>15</volume>
            <elocation-id>5788</elocation-id>
            <pub-id pub-id-type="doi">10.3390/su15075788</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B36">
        <label>36.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Derbal, K. (2013) Digestion anaérobie des déchets solides mélangés avec les boues de station d’épuration. Thèse en Génies de l’environnement, Université Mentouri Constantine, 148 p.</mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Derbal, K.</string-name>
            </person-group>
            <year>2013</year>
            <article-title>Digestion anaérobie des déchets solides mélangés avec les boues de station d’épuration</article-title>
            <source>Thèse en Génies de l’environnement</source>
            <volume>148</volume>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B37">
        <label>37.</label>
        <citation-alternatives>
          <mixed-citation publication-type="journal">Prado, I., Prado, R., Rotta, P., Visantainer, J., Moletta, J. and Perotto, D. (2008) Carcass Characteristics and Chemical Composition of the <italic>longissimus</italic> Muscle of Crossbred Bulls ( <italic>Bos</italic><italic>Taurus</italic><italic>Indicus</italic> vs <italic>Bos</italic><italic>Taurus</italic><italic>Taurus</italic>) Finished in Feedlot. <italic>Journal</italic><italic>of</italic><italic>Animal</italic><italic>and</italic><italic>Feed</italic><italic>Sciences</italic>, 17, 295-306. https://doi.org/10.22358/jafs/66609/2008 <pub-id pub-id-type="doi">10.22358/jafs/66609/2008</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.22358/jafs/66609/2008">https://doi.org/10.22358/jafs/66609/2008</ext-link></mixed-citation>
          <element-citation publication-type="journal">
            <person-group person-group-type="author">
              <string-name>Prado, I.</string-name>
              <string-name>Prado, R.</string-name>
              <string-name>Rotta, P.</string-name>
              <string-name>Visantainer, J.</string-name>
              <string-name>Moletta, J.</string-name>
              <string-name>Perotto, D.</string-name>
            </person-group>
            <year>2008</year>
            <article-title>Carcass Characteristics and Chemical Composition of the longissimus Muscle of Crossbred Bulls (Bos Taurus Indicus vs Bos Taurus Taurus) Finished in Feedlot</article-title>
            <source>Journal of Animal and Feed Sciences</source>
            <volume>17</volume>
            <pub-id pub-id-type="doi">10.22358/jafs/66609/2008</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B38">
        <label>38.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">van Lier, J.B., Mahmoud, N. and Zeeman, G. (2008) Anaerobic Wastewater Treat-ment. In: Henze, M., van Loosdrecht, M.C.M., Ekama, G.A. and Brdjanovic, D., Éds., <italic>Biological</italic><italic>Wastewater Treatment</italic>: <italic>Principles</italic>, <italic>Modelling</italic><italic>and</italic><italic>Design</italic>, IWA Publishing, 415-457.</mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Lier, J.B.</string-name>
              <string-name>Mahmoud, N.</string-name>
              <string-name>Zeeman, G.</string-name>
              <string-name>Henze, M.</string-name>
              <string-name>Loosdrecht, M.C.M.</string-name>
              <string-name>Ekama, G.A.</string-name>
              <string-name>Brdjanovic, D.</string-name>
              <string-name>Principles, M</string-name>
              <string-name>Design, I</string-name>
            </person-group>
            <year>2008</year>
            <article-title>Anaerobic Wastewater Treat-ment</article-title>
            <source>In: Henze</source>
            <volume>415</volume>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B39">
        <label>39.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Ariunbaatar, J., Panico, A., Esposito, G., Pirozzi, F. and Lens, P.N.L. (2014) Pretreatment Methods to Enhance Anaerobic Digestion of Organic Solid Waste. <italic>Applied</italic><italic>Energy</italic>, 123, 143-156. https://doi.org/10.1016/j.apenergy.2014.02.035 <pub-id pub-id-type="doi">10.1016/j.apenergy.2014.02.035</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/j.apenergy.2014.02.035">https://doi.org/10.1016/j.apenergy.2014.02.035</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Ariunbaatar, J.</string-name>
              <string-name>Panico, A.</string-name>
              <string-name>Esposito, G.</string-name>
              <string-name>Pirozzi, F.</string-name>
              <string-name>Lens, P.N.L.</string-name>
            </person-group>
            <year>2014</year>
            <article-title>Pretreatment Methods to Enhance Anaerobic Digestion of Organic Solid Waste</article-title>
            <source>Applied Energy</source>
            <volume>123</volume>
            <pub-id pub-id-type="doi">10.1016/j.apenergy.2014.02.035</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B40">
        <label>40.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Angelidaki, I. and Ahring, B.K. (2000) Methods for Increasing the Biogas Potential from the Recalcitrant Organic Matter Contained in Manure. <italic>Water Science and</italic><italic>Technology</italic>, 41, 189-194. https://doi.org/10.2166/wst.2000.0071 <pub-id pub-id-type="doi">10.2166/wst.2000.0071</pub-id><pub-id pub-id-type="pmid">11381991</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.2166/wst.2000.0071">https://doi.org/10.2166/wst.2000.0071</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Angelidaki, I.</string-name>
              <string-name>Ahring, B.K.</string-name>
            </person-group>
            <year>2000</year>
            <article-title>Methods for Increasing the Biogas Potential from the Recalcitrant Organic Matter Contained in Manure</article-title>
            <source>Water Science and Technology</source>
            <volume>41</volume>
            <pub-id pub-id-type="doi">10.2166/wst.2000.0071</pub-id>
            <pub-id pub-id-type="pmid">11381991</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B41">
        <label>41.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Hartig, S. (2010) Guide sur le biogaz: De la production a l’utilisation. rapport d’étude. Centre de Compétence Développement des Ressources Humaines (DRH)—Programmes Méditerrané et Moyen-Orient, 247 p.</mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Hartig, S.</string-name>
            </person-group>
            <year>2010</year>
            <article-title>Guide sur le biogaz: De la production a l’utilisation</article-title>
            <source>rapport d’étude. Centre de Compétence Développement des Ressources Humaines (DRH)—Programmes Méditerrané et Moyen-Orient</source>
            <volume>247</volume>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B42">
        <label>42.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Franke-Whittle, I.H., Walter, A., Ebner, C. and Insam, H. (2014) Investigation into the Effect of High Concentrations of Volatile Fatty Acids in Anaerobic Digestion on Methanogenic Communities. <italic>Waste</italic><italic>Management</italic>, 34, 2080-2089. https://doi.org/10.1016/j.wasman.2014.07.020 <pub-id pub-id-type="doi">10.1016/j.wasman.2014.07.020</pub-id><pub-id pub-id-type="pmid">25164858</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/j.wasman.2014.07.020">https://doi.org/10.1016/j.wasman.2014.07.020</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Franke-Whittle, I.H.</string-name>
              <string-name>Walter, A.</string-name>
              <string-name>Ebner, C.</string-name>
              <string-name>Insam, H.</string-name>
            </person-group>
            <year>2014</year>
            <article-title>Investigation into the Effect of High Concentrations of Volatile Fatty Acids in Anaerobic Digestion on Methanogenic Communities</article-title>
            <source>Waste Management</source>
            <volume>34</volume>
            <pub-id pub-id-type="doi">10.1016/j.wasman.2014.07.020</pub-id>
            <pub-id pub-id-type="pmid">25164858</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B43">
        <label>43.</label>
        <citation-alternatives>
          <mixed-citation publication-type="web">Mazeghrane, S. (2014) Optimisation de la production anaérobie d’acides gras volatils à partir des boues d’épuration par le contrôle-commande de l’ajout de dioxyde de carbone. https://hal.inrae.fr/tel-02794882</mixed-citation>
          <element-citation publication-type="web">
            <person-group person-group-type="author">
              <string-name>Mazeghrane, S.</string-name>
            </person-group>
            <year>2014</year>
            <article-title>Optimisation de la production anaérobie d’acides gras volatils à partir des boues d’épuration par le contrôle-commande de l’ajout de dioxyde de carbone</article-title>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B44">
        <label>44.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Izumi, K., Okishio, Y., Nagao, N., Niwa, C., Yamamoto, S. and Toda, T. (2010) Effects of Particle Size on Anaerobic Digestion of Food Waste. <italic>International Biodeterioration</italic><italic>&amp;</italic><italic>Biodegradation</italic>, 64, 601-608. https://doi.org/10.1016/j.ibiod.2010.06.013 <pub-id pub-id-type="doi">10.1016/j.ibiod.2010.06.013</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/j.ibiod.2010.06.013">https://doi.org/10.1016/j.ibiod.2010.06.013</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Izumi, K.</string-name>
              <string-name>Okishio, Y.</string-name>
              <string-name>Nagao, N.</string-name>
              <string-name>Niwa, C.</string-name>
              <string-name>Yamamoto, S.</string-name>
              <string-name>Toda, T.</string-name>
            </person-group>
            <year>2010</year>
            <article-title>Effects of Particle Size on Anaerobic Digestion of Food Waste</article-title>
            <source>International Biodeterioration &amp; Biodegradation</source>
            <volume>64</volume>
            <pub-id pub-id-type="doi">10.1016/j.ibiod.2010.06.013</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B45">
        <label>45.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Batstone, D.J., Keller, J., Angelidaki, I., Kalyuzhnyi, S.V., Pavlostathis, S.G., Rozzi, A., Sanders, W.T.M., Siegrist, H. and Vavilin, V.A. (2002) The IWA Anaerobic Digestion Model No 1 (ADM1). <italic>Water Science and Technology</italic>, 45, 65-73. https://doi.org/10.2166/wst.2002.0292 <pub-id pub-id-type="doi">10.2166/wst.2002.0292</pub-id><pub-id pub-id-type="pmid">12188579</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.2166/wst.2002.0292">https://doi.org/10.2166/wst.2002.0292</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Batstone, D.J.</string-name>
              <string-name>Keller, J.</string-name>
              <string-name>Angelidaki, I.</string-name>
              <string-name>Kalyuzhnyi, S.V.</string-name>
              <string-name>Pavlostathis, S.G.</string-name>
              <string-name>Rozzi, A.</string-name>
              <string-name>Sanders, W.T.M.</string-name>
              <string-name>Siegrist, H.</string-name>
              <string-name>Vavilin, V.A.</string-name>
            </person-group>
            <year>2002</year>
            <article-title>The IWA Anaerobic Digestion Model No 1 (ADM1)</article-title>
            <source>Water Science and Technology</source>
            <volume>45</volume>
            <pub-id pub-id-type="doi">10.2166/wst.2002.0292</pub-id>
            <pub-id pub-id-type="pmid">12188579</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B46">
        <label>46.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Awe, O.W., Zhao, Y., Nzihou, A., Minh, D.P. and Lyczko, N. (2017) A Review of Biogas Utilisation, Purification and Upgrading Technologies. <italic>Waste Biomass Valorization</italic>, 8, 267-283. https://doi.org/10.1007/s12649-016-9826-4 <pub-id pub-id-type="doi">10.1007/s12649-016-9826-4</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1007/s12649-016-9826-4">https://doi.org/10.1007/s12649-016-9826-4</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Awe, O.W.</string-name>
              <string-name>Zhao, Y.</string-name>
              <string-name>Nzihou, A.</string-name>
              <string-name>Minh, D.P.</string-name>
              <string-name>Lyczko, N.</string-name>
              <string-name>Utilisation, P</string-name>
            </person-group>
            <year>2017</year>
            <article-title>A Review of Biogas Utilisation, Purification and Upgrading Technologies</article-title>
            <source>Waste Biomass Valorization</source>
            <volume>8</volume>
            <pub-id pub-id-type="doi">10.1007/s12649-016-9826-4</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B47">
        <label>47.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Panza, D. and Belgiorno, V. (2010) Hydrogen Sulphide Removal from Landfill Gas. <italic>Process Safety and Environmental Protection</italic>, 88, 420-424. https://doi.org/10.1016/j.psep.2010.07.003 <pub-id pub-id-type="doi">10.1016/j.psep.2010.07.003</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1016/j.psep.2010.07.003">https://doi.org/10.1016/j.psep.2010.07.003</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Panza, D.</string-name>
              <string-name>Belgiorno, V.</string-name>
            </person-group>
            <year>2010</year>
            <article-title>Hydrogen Sulphide Removal from Landfill Gas</article-title>
            <source>Process Safety and Environmental Protection</source>
            <volume>88</volume>
            <pub-id pub-id-type="doi">10.1016/j.psep.2010.07.003</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B48">
        <label>48.</label>
        <citation-alternatives>
          <mixed-citation publication-type="journal">Elasri, O. and El Afilal, M.A. (2016) Potential for Biogas Production from the Anaerobic Digestion of Chicken Droppings in Morocco. <italic>International Journal of Recycling</italic><italic>of Organic Waste in Agriculture</italic>, 5, 195-204 https://doi.org/10.1007/s40093-016-0128-4 <pub-id pub-id-type="doi">10.1007/s40093-016-0128-4</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1007/s40093-016-0128-4">https://doi.org/10.1007/s40093-016-0128-4</ext-link></mixed-citation>
          <element-citation publication-type="journal">
            <person-group person-group-type="author">
              <string-name>Elasri, O.</string-name>
              <string-name>Afilal, M.A.</string-name>
            </person-group>
            <year>2016</year>
            <article-title>Potential for Biogas Production from the Anaerobic Digestion of Chicken Droppings in Morocco</article-title>
            <source>International Journal of Recycling of Organic Waste in Agriculture</source>
            <volume>5</volume>
            <pub-id pub-id-type="doi">10.1007/s40093-016-0128-4</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
      <ref id="B49">
        <label>49.</label>
        <citation-alternatives>
          <mixed-citation publication-type="other">Nikiema, M., Barsan, N., Ouili, A.S., Mosnegutu, E., Somda, K.M., Maiga, Y., Tidi-ane, C.C.O., Ouattara, C.A.T., Nedeff, V. and Ouattara, A.S. (2024) Determination of Particle Size for Optimum Biogas Production from Ouagadougou Municipal Organic Solid Waste. <italic>Sustainability</italic>, 16, Article 9792. https://doi.org/10.3390/su16229792 <pub-id pub-id-type="doi">10.3390/su16229792</pub-id><ext-link ext-link-type="uri" xlink:href="https://doi.org/10.3390/su16229792">https://doi.org/10.3390/su16229792</ext-link></mixed-citation>
          <element-citation publication-type="other">
            <person-group person-group-type="author">
              <string-name>Nikiema, M.</string-name>
              <string-name>Barsan, N.</string-name>
              <string-name>Ouili, A.S.</string-name>
              <string-name>Mosnegutu, E.</string-name>
              <string-name>Somda, K.M.</string-name>
              <string-name>Maiga, Y.</string-name>
              <string-name>Tidi-ane, C.C.O.</string-name>
              <string-name>Ouattara, C.A.T.</string-name>
              <string-name>Nedeff, V.</string-name>
              <string-name>Ouattara, A.S.</string-name>
            </person-group>
            <year>2024</year>
            <article-title>Determination of Particle Size for Optimum Biogas Production from Ouagadougou Municipal Organic Solid Waste</article-title>
            <source>Sustainability</source>
            <volume>16</volume>
            <elocation-id>9792</elocation-id>
            <pub-id pub-id-type="doi">10.3390/su16229792</pub-id>
          </element-citation>
        </citation-alternatives>
      </ref>
    </ref-list>
  </back>
</article>