Is Low-Carbon Together with Pollution Reduction? - Calculation of CO2 Emissions from Municipal Wastewater Treatment Plants

Municipal wastewater treatment plants (WWTP) are recognized as an important source of carbon emissions. Previous studies have calculated the CO₂ emissions in the operating process of WWTP in the sight of engineering technology and the CO₂ emission which is driven by the pulling effect of investment in WWTP are ignored. This paper calculates the CO₂ emissions of wastewater treatment plant from the macroscopic view based on the input-output method and the fixed log-liner model. The study discovers that Compared to the indirect CO₂ emissions from WWPT, the direct carbon dioxide emissions from WWPT are negligible. It calculates that in the year 2007, China´s CO₂ emissions of WWTP in construction process amount to 98.23 million tons and the emissions in operating process is 11.24 million tons. The indirect emissions are 8.74 times the direct emissions; and the reduction of 1 ton of COD pollutants generates about 14.7 tons of carbon dioxide emissions.