Methane emission at the main stages of technological cycle of sewage waste water purification at Rostov-on-Don aeration station

Abstract

The methane concentration in the waste water coming to the aeration station is 1130 μl/l on average and it decreases to 11 μl/l after all purification stages. Experimentally measured methane fluxes to the atmosphere from the waste water under purification and sewage sediments of silt fields varied within 0.2–50.1 and 98.3–188.8 mg/m2 per hour, respectively, and correlated closely enough with the gas content in them. An approximate total methane emission by the purification plants is about 475 kg per day and the major contribution (83%) belongs to the silt field sediments characterized by its extremely high content (42.42–199.49 μg/g of the damp sediment). It is demonstrated that the regression equations obtained by the authors before and approximating the relation of the methane content in the water and bottom deposits of water bodies with its fluxes to the atmosphere can be used to estimate the methane amount emitted during the waste water purification.