|
Abstract
|
The global water crisis reflects the necessity of exploring the best approaches for the water supply. Therefore, for the
first time, the current study compares nitrogen removal systems (NRSs) from life cycle assessment (LCA), economic,
kinetic, thermodynamic, and synergistic perspectives. The assessed systems were sequential batch reactor (SBR),
oxic/anoxic (OA), and oxic/anaerobic/oxic (OAO) bioreactors. Among all, the SBR configuration showed the best efficiency (98.74 %) for nitrogen removal. The environmental impacts notably presented by marine + freshwater
ecotoxicity (53.76 %), and climate change categories (16.39 %), significantly because of metal emissions. Nonrenewable sources supplied 95 % of total energy demand. The operation of NRSs showed the most impact on
human health (63.67 %) through CH4 and CO2 emissions. The total costs significantly belonged to the construction
(<86.37 %) > amortization> operation. The influent COD illustrated the most role in environmental burdens
(16.44 %) based on the sensitivity analysis. The removal reaction was endothermic, physical, non-spontaneous, and
followed a pseudo-second-order kinetic model (R2 > 0.98). The chemical exergy provided the major portion of the
total calculated exergy (83 %). The exergetic efficiency of the system was 69 %, which was predominantly supplied
by biogas (∼50.75 %). Accordingly, this study can present a stepwise guideline for further related investigations.
|