GREENHOUSE GAS EMISSIONS FROM WASTEWATER TREATMENT PLANT

Climate change is influenced by several environmental and social factors, in which emissions of greenhouse gases to the atmosphere is one of the most important factor. Though some greenhouse gas emission happens through natural processes, but the major share of greenhouse gas emission comes from anthropogenic activities such as burning of fossil fuels, industrial processes etc. Waste sector contributes to 4% of the total greenhouse gas emissions in India. Out of this 4%, greenhouse gas emission from domestic wastewater is around 60%. Also, there is a wide gap existing between the generation of wastewater from domestic sources and the available treatment capacity for them. Thus, wastewater treatment plants in Indian cities are increasing the pressure on energy consumption and aggravating greenhouse gas emissions. Therefore, reducing the energy and carbon footprints of wastewater treatment is necessary for improving the sustainability of wastewater treatment plants. In this study energy and carbon footprints of Navi Mumbai, wastewater treatment plants were estimated. For the estimation of energy consumption, mass-balance approach and the IPCC methodology for carbon emission were used. The energy footprint of the wastewater treatment plants was 22.534 kWh/m3 . The energy footprint results showed that the embodied energy of the material was greater than the electrical energy used in the plant. 92% of the whole energy was shared by embodied energy. Average electrical consumption of wastewater treatment plants has been evaluated as 0.24 kWh/m3 . It was estimated that the carbon footprint of the wastewater treatment plants is 9.66443 kgCO2eq/m3 . The off-site carbon emissions with the indirect carbon emissions were significantly higher than the on-site emissions. The contribution of the off-site carbon emissions and indirect carbon emissions were 98.06%.