چكيده به لاتين
Global warming and climate change have created a variety of economic and environmental problems for many countries. Researchers and scientists have shown that if anthropogenic greenhouse gas emissions get increased by the current slope, the consequences will be irreparable. Municipal wastewater treatment plants are one of the main sources of greenhouse gas emissions. The collection, transmission, treatment and disposal of municipal wastewater causes the emissions of Cabon Dioxide (CO2), Nitros Oxide (N2O) and methane (CH4). In many major cities around the world, there is still no accurate statistics on the amount of greenhouse gas emissions from sewage treatment plants. The city of Tehran, as one of the most populous cities in the world and one of the densest capitals in the world, has 7 municipal wastewater treatment plants and non of which have not yet been thoroughly studied on direct and indirect greenhouse gas emissions. One of the pervasive methods that researchers and scientists have used worldwide to measure the amount of greenhouse gas emissions are IPCC guidelines. Most studies have been using this method and so far the 2006 version is the most used version. While in the 2019 version, this guideline has updated the emission factors. For this reason, both versions of these guidelines were used to measure greenhouse gas emissions from Tehran's wastewater treatment plants. But because these methods only consider the amount of nitrose oxide and methane from the treatment plants, and the indirect emissions of the refineries are ignored, the comprehensive method of greenhouse gas emissions was also used in Tehran. To apply this method, qualitative data and information on the input and effluent of sewage were collected from each treatment plant, the energy consumed by each unit was investigated and the amount of heavy vehicles were carried out; Therefore, direct and indirect emissions were calculated from Tehran municipal wastewater treatment plants. According to the results obtained, according to IPCC 2006, the total greenhouse gas emissions from Tehran municipal wastewater treatment plants were equivalent to 184036 tons of CO2 in the year, and according to the 2019 IPCC version, this amount was equivalent to 209862 tonnes of CO2 per year. This significant difference between the IPCC methods is due to the changes in the emission factors offered in the 2019 edited version. According to the results based on Bridle, the amount of greenhouse gas emissions in 1399 from Tehran's municipal wastewater treatment plants was equivalent to 43078 tons of CO2. This is much less than the results obtained according to different versions of the IPCC instructions. This shows that the IPCC method overestimates the emissions and emissions factors need to be modified. The south of Tehran sewage treatment plant with the release of 28741 carbon dioxide had the highest share of this amount. Also, in the field of energy consumption, this plant showed the best performance among all treatment plants with 15.24 kWh per year for each person covered. The worse energy performance was for Zargandeh wastewater treatment plant, with consumption of 87.67 kWh per year for each person covered and Shahrak-gharb wastewater treatment plant, consumed 1.44 kWh per cubic meter of sewage influent. Finally, after identifying the total amount of greenhouse gas emitted from each of Tehran's wastewater treatment plants and the energy consumption of each, the most economical scenario was presented to reduce greenhouse gas emissions by reducing the energy consumption of the plants. The results of this study will be very practical for future studies to optimize the sustainability of Tehran's wastewater treatment plants as well as their environmental performance
