Economic analysis of the scale-up and implantation of a hollow fibre membrane contactor plant for nitrogen recovery in a full-scale wastewater treatment plant

Abstract

[EN] Nitrogen recovery technologies such as the hollow fibre membrane contactor are now being developed. However, an economic analysis is needed prior to their full-scale application in wastewater treatment plants. The aim of this study was to analyse the economic and environmental aspects of scaling-up this method. To achieve it, a full-scale 40,000 m3·day¿1-wastewater treatment plant influent flow rate was simulated jointly with a membrane contactor plant to evaluate the minimum costs of optimum operating conditions of membrane contactors (pH, feed flow rate and membrane surface). The optimum conditions for treating 600 m3·day¿1 of reject water was found to be 10 pH, 0.08 m3·s¿1 feed flow rate and 10,580 m2 of membrane surface, obtaining a 4% nitrogen ammonia sulphate solution. The results indicated capital (membrane modules and pumps) and operating costs (reagents and energy) of 0.0095 €·m¿3 and a profit of 0.0090 €·m¿3, including energy savings in terms of aeration and sales of the recovered ammonia sulphate, with the added benefit of reducing CO2-eq by 10.3 tons per day.