Modelling the catchment-scale environmental impacts of wastewater treatment in an urban sewage system for CO2 emission assessment

摘要

Water shortages and water pollution are a global problem. Increases in population can havenfurther acute effects on water cycles and on the availability of water resources. Thus, wastewaternmanagement plays an important role in mitigating negative impacts on natural ecosystemsnand human environments and is an important area of research. In this study, we modelledncatchment-scale hydrology, including water balances, rainfall, contamination, and urbannwastewater treatment. The entire water resource system of a basin, including a forest catchmentnand an urban city area, was evaluated synthetically from a spatial distribution perspective withnrespect to water quantity and quality; the Life Cycle Assessment (LCA) technique was applied tonoptimize wastewater treatment management with the aim of improving water quality and reducingnCO2 emissions. A numerical model was developed to predict the water cycle and contamination innthe catchment and city; the effect of a wastewater treatment system on the urban region wasnevaluated; pollution loads were evaluated quantitatively; and the effects of excluding rainwaternfrom the treatment system during flooding and of urban rainwater control on water quality werenexamined. Analysis indicated that controlling the amount of rainwater inflow to a wastewaterntreatment plant (WWTP) in an urban area with a combined sewer system has a large impact onnreducing CO2 emissions because of the load reduction on the urban sewage system.