Composition of biogas determination: For the collection of the biogas, a small volume of n-Hexane was dispensed in a small glass bottle and the bottle was gently put at the tip of the gas valve of the digester, which was then opened, to collect the biogas sample. The sample was transferred into 20ml capacity vial glass container with no addition of reagents carried out. The vials were capped with hand tool capper made of aluminum materials. The sample in the glass vials were placed in the sample holder of the HP HEADSPACE SAMPLER. The temperature of the operation of the Headspace sampler was 300C. The Headspace sampler was connected to the Gas Chromatography (GC) for the injection into the GC column in an automated manner after completing the operational cycle. The standard gas mixture in the glass vials was placed in the Headspace sample hole. The connection with the GC was activated in an automated manner. The standard mixture and samples were analyzed under the same conditions.