Bio-digester is a storage cum reaction vessel for Human / Kitchen Waste where the Human / Kitchen Waste comes into contact with bacteria specially developed for digesting the waste & converting into Biogas & water as bi-product. These Bio-digesters are made of steel or FRP insulated with PUF & again covered with FRP, depending on the location of use of these Bio-digesters. Once installed, these Bio-digesters will never stop working until some man-induced chemicals kill these bacteria. These chemicals can be commonly used phenyl, soap, detergents etc. The steel Bio-digesters are used where the sub-soil temperature does not go below 5º C. These bio-digester do not require any heating and hence are quite cost effective. The FRP – PUF Bio-digesters are used where the ambient / sub-soil temperature goes below zero degree & hence, to sustain the Bio-chemical reaction, the heating is required which is provided by solar-powered heaters. The temperature is controlled by a temperature-controller. The temperature display is provided & the data logger can store the temperature every three hours. During night, when the solar power is not available, the temperature controller is automatically switched OFF