Life cycle environmental and economic assessment of human night soil based Malaprabha biogas plant

Abstract

India's inadequate faecal sludge management continues to be a source of concern and to tackle this problem Dr. S. V. Mapuskar has proposed “Malaprabha digester” a hygienically safe and environmentally sustainable solution. The current research was carried out to evaluate life cycle assessment (LCA) and life cycle cost assessment (LCCA) of human night soil based Malaprabha biogas plant. LCA and LCCA were conducted with impact 2002+ method (with 14 midpoint and 4 damage categories) and present worth (PW) method as mentioned in Bureau of Indian Standards IS 13,174 (1991) part 2 respectively. Herein, the case study pertains to the design of the digester for 890 habitants of a high-rise building (G + 30). The results showed that the system’s operational phase mainly contributes to eutrophication, acidification and ecotoxicity potential whereas, the most detrimental emissions of the construction phase were determined by the use of cement, steel and PVC materials. Since the emission of methane during anaerobic digestion can be fully trapped in the Malaprabha digester, it can assist in enhancing greenhouse gas sinks. Moreover, Economic assessment of this on-site treatment of night soil represents monitory benefits by replacing cooking gas (LPG) with biogas for 30 min per day per family. Thus, by utilizing Malaprabha digester as a source of biogas, dependency on fossil fuels is being reduced in a sustainable way and costs would be saved for the construction of the septic tank.