The book contains detailed information about the human waste generated pollution in remote locations bearing sub-zero temperatures in addition to Railways, Islands and other public places. Description has been made as a scientific journey about the sequential technology development for various applications. Due consideration has been given and described about the practical viability of the product in terms of living habits of the users as well as its transportability, affordability and acceptability by public sector and the society including the environmental impacts of technology. Selection of methanogenic bacteria with the ability to work in broad temperature range, resisting freezing damages and toilet cleaning agents have been described in length. Limited volume, high bacterial density fermentation, immobilization of bacteria, energy constraints and durability had been the important criteria for designing the bio-digesters. User’s awareness, habits and negligence in combination with lack of commitment of implementing authorities have been the main challenges during the development of the equipments, field trials and their application which has been described as experienced.