Nitrogen is one of the most critical nutrients in the biosphere, and it is an essential nutrient for plant growth. Nitrogen exists in the atmosphere vastly as a gaseous form, but only reactive nitrogen is usable for plants. It is a valuable resource and worth recovering in the wastewater sector. The aim of this work was to prepare a comprehensive environmental analysis of a novel membrane contactor-based process, which is capable of highly efficient nitrogen removal from wastewater. Life cycle assessment (LCA), PESTLE and multi-criteria decision analysis (MCDA) were applied to evaluate the process. The EF 3.0 method, preferred by the European Commission, IMPACT World+, ReCiPe 2016 and IPCC 2021 GWP100 methods were used with six different energy resources-electricity high voltage, solar, nuclear, heat and power and wind energy. The functional unit of 1 m3 of water product was considered as output and "gate-to-gate" analysis was examined. The results of our study show that renewable energy resources cause a significantly lower environmental load than traditional energy resources. TOPSIS score was used to evaluate the alternatives in the case of MCDA. For the EU region, the most advantageous option was found to be wind energy onshore with a score of 0.76, and the following, nuclear, was 0.70.
Keywords: life cycle assessment; membrane gas separation; multi-criteria decision analysis; nitrogen recovery; pestle.