Optimization of Biogas Production from Organic Municipal Waste: Development of Activated Sludge as Digesters Inoculum

Abstract

This study is a contribution to the optimization of organic fraction of municipal waste bioconversion into biomethane, by activated sludge production as inoculum for digesters. The wastewater (WW) and cow dung (CD) samples were taken from the slaughterhouse of Ouagadougou town, Burkina Faso. Different mixtures were made, enriched with mineral solution and cellulose at 5% (w/v) as: 10% CD + 90% WW (C7), 30% CD + 70% WW (C6), 50% CD + 50% WW (C5), 70% CD + 30% WW (C4), 90% CD + 10% WW (C3), 100% CD (C2) and 100% WW (C1). The pH evolution and biogas (CH 4 and CO 2) production were followed for 25 days. Cultures tend to acidify with increase in cow dung proportion. Biogas production was significantly higher (p < 0.05) in C5 (880.0 mL), C6 (862.0 10 mL) and C7 (772.0 mL). Mixture C5 had a highest level of CO 2 production (40%). Also C7 and C6 retained in the experiment contained respectively organic matter, volatile fatty acids (VFA) and total alkalinity (TAC) as 41.06%, 47.02%, 1320 mg acetic acid/L, 3036 mg Acetic acid/L and 520 mg CaCO 3 /L, 1310 mg CaCO 3 /L. Mixture C6 was the best medium for microorganism proliferation stability with 3.5 × 10 5 UFC/ml of methanogens bacteria. It also possessed buffering capacity, which prevents acidification of medium during VFAs production.

Valorization of Agricultural Waste: Theoretical Estimation and Experimental Biomethane Yield from Cashew Nut Hulls

“…The amount of inoculum placed represented 10% (v/v) in a final volume of 40 mL. The inoculum was an activated sludge, prepared by mixing wastewater and old reactor sludge according to technique described by [34]. After inoculation, bottle was hermetically sealed with screw caps fitted with a septum to guarantee perfect gas tightness.…”

The Effect of Fermentation Time to Biogas Production From Cow Dung and Sour Water

“…Nikiema, et.al (2017) conducted a study using cow dung and wastewater with inoculum in the form of activated sludge with a total feed volume of 100 ml with a 25-day study. The optimal total volume is obtained at 50% cow dung and 50% wastewater, which is 880 ml (Nikièma, et al, 2017). The optimal independent variables in this study are the same as the fixed variables in this study, namely wastewater and cow dung used in a 1:1 ratio.…”

Effects of Heavy Metal Ions (Fe&lt;sup&gt;3+&lt;/sup&gt;, Cu&lt;sup&gt;2+&lt;/sup&gt;, Zn&lt;sup&gt;2+&lt;/sup&gt; and Cr&lt;sup&gt;3+&lt;/sup&gt;) on the Productivity of Biogas and Biomethane Production

“…The effect of heavy metal ions (Me + ) on the process of anaerobic fermentation is associated with the uncontrolled content of metal-containing compounds in the raw material entering the fermentation (for example, organic municipal waste [1]), which can lead to inhibition of anaerobic association of microorganisms by the following mechanisms:…”