Abstract: “Egypt is a typical example of a developing country which is highly vulnerable to climate change. The weather patterns changes and the rise in seawater level in the Nile Delta are slow but the unremitting rate makes a difficult situation become worse, particularly in the area of food and water (Delta region). Egypt ranks the 94th in terms of per capita emissions with an average of 2.3 tons of CO2 per person and 29th in the list of global polluters with 0.59% of global emissions. Estimating greenhouse gases emissions (GHGs) from wastewater treatment plants (WWTPs) is the first step to avoid the consequences of climate change and thus mitigating the quantity of GHGs. Therefore, an attempt was made in this study to estimate GHGs emissions from large WWTPs using two methods: IPCC, and USEPA, and then compare both with computer simulation program. In this study, GHGs emissions were estimated in the years 2018, and 2022 respectively for the case study (the Eastern Wastewater Treatment Plant i”

Keywords: Greenhouse gases, Climate change, CO2 emission, N2O emission, IPCC guidelines, EPA guidelines, Three Scopes method, Wastewater Treatment, Modeling, and simulation.