Environmental and economic assessment of urban wastewater reclamation from ultrafiltration membrane-based tertiary treatment: Effect of seasonal dynamic

Abstract

This study aimed to assess the environmental and economic performance of an ultrafiltration (UF) tertiary treatment of effluent from an urban wastewater treatment facility. Data from a UF demonstration plant composed of commercially available equipment, including industrial hollow-fiber membranes was used to project a full-scale facility. The results from the demonstration plant recommended different ranges of transmembrane fluxes and sparging air demands under summer and winter conditions to prevent excessive fouling. The energy balance of the full-scale facility would be 0.308 ± 0.112 kWh·m −3 in summer and 0.140 ± 0.040 kWh·m −3 in winter, with blowers' being the main consumers (86–93 %). CAPEX accounted for €0.030 ± 0.002·m −3 in summer and €0.027 ± 0.002·m −3 in winter and membrane acquisition represented 66–69 % of the investment cost. Energy expenditure was the major OPEX cost (66–79 %), with a total operating cost of €0.077 ± 0.023·m −3 and €0.042 ± 0.008·m −3 in summer and winter, respectively. The final average value obtained for the TAC was €0.107 m −3 in summer and €0.068 m −3 in winter. The environmental assessment confirmed optimizing energy consumption and membrane requirements as the main factors influencing environmental sustainability. Specifically, summer and winter emissions of 0.079–0.175 and 0.043–0.079 kgCO 2eq ·m −3 (Global warming potential); 8.1 · 10 −4 –1.7 · 10 −3 and 4.8 · 10 −3 –8.1 · 10 −3 m 3 ·m −3 (water consumption); 0.019–0.041 and 0.010–0.019 kg oil eq ·m −3 (fossil fuel scarcity); and 1.4 · 10 −4 –2.9 · 10 −4 and 7.7 · 10 −4 –1.4 · 10 −4 kg Cu eq ·m −3 (mineral resource scarcity) were calculated, respectively. The obtained permeate quality complied with the most stringent Spanish and EU regulations. • Full-scale UF plant shows energy consumption in the 0.098–0.452 kWh·m −3 range. • CAPEX was estimated at €0.025–0.031·m −3 with membranes as major contributor (66–69 %). • OPEX account for €0.033–0.106·m −3 being energy cost the main expenditure (66–79 %). • LCA showed energy balance as most influential factor on the environmental impact. • UF process allowed accomplishing regulation statements for agriculture reuse.

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