Comparative Study of Thermal and Chemical Pretreatment on the Yield of Biogas from Microcoleus vaginatus Vauch

Authors: Haruna M, Momoh OR, Bilal S

DOI Info: N/A

ABSTRACT

The industrial and household energy demand is rapidly outpacing the available fossil resources which has called for alternatives that will be eco-friendly and cost effective. In this work, potentials of thermal pretreatment in an oven at 70, 75, 80 ^oC and chemical (NaOH) 0.5, 0.6, 0.7 Molar concentration were examined for the enhancement of biogas yield from Microcoleus vaginatus. The results of proximate analysis for untreated sample was 47.6, 5.2, 22.1 4.47, 8.73 and 11.9 % for carbohydrate, moisture, ash, lipids, fibre and protein respectively. The carbohydrates for all treated samples were enhanced. For samples treated at 70, 75 and 80 ^oC the values were 80.62, 79.7, 78.2% and 75.14, 75.1, 74.9% were obtained from 0.5, 0.6 and 0.7 M (NaOH) treated samples. Other nutrients were all reduced except moisture for chemical treated samples. The optimum reduction in moisture was 148 % for thermally treated samples and 15 % increase for chemically treated. The biogas yield for untreated sample was 4.36 mLg^-1 VS and 8.39 mLg^-1 VS, 9.07 mLg^-1 VS and 9.38 mLg?1 VS was obtained at 70, 75 and 80 ^oC equivalent to 1.9, 2.1 and 2.2-fold increase when compared with the untreated sample against 7.99 mLg^-1 VS, 7.38 and 7.0 mLg^-1 VS while, for chemical treated samples which is 1.6, and 1.8 fold for 31 days of retention. In this study thermal pretreatment at 80 ^oC produced the highest yield of biogas and is thus recommended for biogas production from M. vaginatus.

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