Life cycle and environmental impact assessment of vegetation-activated sludge process (V-ASP) for decentralized wastewater treatment

Abstract

The integrated Vegetation-Activated Sludge Process (V-ASP) has emerged as a promising solution for decentralized wastewater treatment, offering a unique combination of landscape vegetation with the traditional Anaerobic-Anoxic-Oxic process (AAO). The experiments displayed that V-ASP consistently demonstrated remarkable treatment performance, maintaining stable removal efficiency exceeding 90 % for COD, NH4+-N, and TP. The vegetation growth is helpful for the removal of pollutants and the microbial community in the allocated vegetation root, while the bulk suspended sludge was changed significantly by using PCR test. To comprehensively evaluate the environmental footprint of V-ASP, a Life Cycle Assessment (LCA) was conducted. The mass balance calculation containing wastewater treatment performance, energy consumption, vegetation growth behavior, greenhouse gas (GHG) emissions, treated water, and sludge discharge was carried out to establish the life cycle inventories (LCI). SimaPro 9.0 software and the ReCiPe (H) midpoint impact assessment method were employed, which revealed that the V-ASP system boasts low GHG emissions and freshwater eutrophication potential compared to the traditional AAO process. In essence, this study provides a comprehensive understanding of the V-ASP system, especially the environmental impacts, guiding its potential for sustainable decentralized sewage treatment applications.