GREENHOUSE GAS EMISSIONS INVENTORY OF WASTEWATER TREATMENT PLANTS OF DELHI/NCR

Abstract

During the last 200 years the atmospheric concentrations of greenhouse gases (GHGs) have been increasing. Human activities such as agriculture, industry, waste disposal, deforestation, and especially increasing use of fossil fuels have been producing increasing amounts of GHGs. For example, the concentrations of CO2 increased from approximately 280 part per million by volume (ppmv) in pre-industrial age to 372.3 ppmv in 2001 and it will continue to increase at about 0.5% per year1, whereas current CH4 atmospheric concentration is going up at a rate 0.02 ppmv per year2. Furthermore, the annual sources of N2O have been increased from the surface of the Earth by about 40–50% over pre-industrial levels. As a result, variations in the radiative forcing of Earth‘s atmosphere could be produced, so leading to large and rapid changes in the earth‘s climate due to global warming produced by these gases. Waste water treatment system generates significant amount of greenhouse gases mainly Methane (CH4) and Nitrous Oxide (N2O). Hence, reducing the emission of greenhouse gases from the Waste Water Treatment Plants (WWTPs) is the major concern. The correct understanding and estimation of the greenhouse gases emitted from different points of the plan is essential to tackle this challenge. The WWTPs are based in natural processes and provide a high removal of BOD, COD, organic carbon, nutrients and pathogenic microorganisms from wastewater. Furthermore, they allow recovering energy and nutrients of the wastewater treated, thus their application in developing countries can be appropriated. However, the different transformations and biochemistry processes of organic and nitrogen matter carried out in WWTP produce GHGs emissions, thus contributing to global warming.