Life-cycle atmospheric emissions and energy use of the collection phase of a typical Indian sewerage system

Considerable number of Indian and international studies has focused on the environmental implications of sewage treatment plants. However, not many studies have taken up a comprehensive assessment of the collection phase of the Indian sewage systems. The aim of the present study is to carry out an integrated life-cycle assessment for the collection phase of an Indian wastewater treatment system. The paper develops in the form of a case study for Begusarai sewerage project and attempts to estimate life-cycle air pollution, greenhouse gas emissions and energy consumption for the collection phase of the project. The work consists of developing a life-cycle inventory for pipelines, manholes, pumps and transportation facilities in a typical collection phase, by making use of existing activity data and emission factors from secondary literature (see graphical abstract). Further, the normalized factors for different environmental damage categories are incorporated within the developed inventory to estimate overall life-cycle damage. Initially, the major components for each damage category are identified. For instance, side walls of manholes are major contributors towards PM_2.5 emissions while pumping stations are major energy consumers and CO₂ emitters. High resource consumption is identified as the major damage category, compared to atmospheric emissions. As larger quantities of water need to be treated owing to increasing water use in the country, a discussion on water–energy nexus is required to estimate the implications of sewage systems.