Mohsen Nowrouzi

he design and implementation of eco-environmental wastewater treatment plants (WWTPs) is required due to the acceleration of carbon emission. To minimize the carbon impacts, life cycle assessment (LCA) can be an appropriate technique for comparing WWTPs considering energy supply and carbon release. Although more literature focused on biological phosphorus removal systems, however, their carbon footprint and energy consumption are less investigated. Therefore, Step Bio-P, anaerobic/anoxic/oxic (A2O), and Bardenpho systems were simulated and optimized operationally. The Step Bio-P showed high efficiency for COD (91.71%) and nutrient (>77%) removals while its energy demand indicated an increase of 1.4 to 1.8- fold. Regarding carbon footprint, the Bardenpho system led to the highest release of CO2 which was associated with fossil fuel utilization in electricity production. However, almost 10.83% to 39.97% of overall energy consumption can be recovered by the combined heat and power (CHP) and boiler installation. Moreover, the development of green energy sources has an influential impact on the reduction of carbon emissions. However, more performance assessments and LCA evaluations of WWTPs at the unit process level are still required to identify and improve the system hotspot.