Production and analysis of biogas from plant sources at different starter rates

• Main Author: Umagat, Myrna del Rosario
• Format: text
• Language: English
• Published: Animo Repository 1985
• Subjects: Crop residues as fuel; Biogas; Chemistry
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/1131
• Institution: De La Salle University

An evaluation on the possibility of crop residues and forages to produce biogas as well as soil conditioner from anaerobic fermentation was undertaken. Factors affecting biogas production such as the amount of starter, water dilution, pH, ambient temperature and Carbon/Nitrogen ratio were also investigated. Analysis of the biogas composition by Gas Chromatography instrument and elemental trace analyses of the materials used was also evaluated using the Atomic Absorption Spectrophotometer. Results of the study revealed that the materials tested showed a positive result in biogas production. Bagasse treated with 30 percent starter rate and 1:8 water water dilution gave a gas output of 28.12 cc/g. This was followed in descending order by paragrass treated with 30 percent starter rate and 1:8 water dilution with a mean gas production of 25.30 cc/g followed by napiergrass treated with 30 percent starter rate and 1:6 water dilution with a mean gas production of 20.62 cc/g and sawdust gave a mean production output of 18.25 cc/g subjected to 30 percent starter rate and 1:8 water dilution. Analysis of variance revealed that the gas production output of the four materials used was significantly affected by the starter added. However, insignificant result was found on the effect of water dilution on the materials tested. Results of the analysis of the gas samples produced from the materials under study revealed that the gas is a mixture of methane (CH4), carbon dioxide (CO2) and hydrogen (H2). Carbon dioxide and hydrogen are the immediate precursors in the bioconversion to methane. The main fuel component is methane -- a colorless and odorless gas which burns with a faint blue flame. Result from the analysis of the solid and liquid sludge using the Atomic Absorption Spectrophometer showed that it contains the necessary elements such as nitrogen, potassium, phosphorus and other trace elements like calcium, sulfur, magnesium, copper, zinc and manganese necessary for plant growth. This may be so since when organic materials are decomposed anaerobically, only the carbon and oxygen on the form of methane (CH4) and carbon dioxide (CO2) are lost and all other essential elements are retained in the sludge.