Cost assessment and retro-techno-economic analysis of desalination technologies in onshore produced water treatment

Due to stricter environmental regulations and lack of other alternatives, saline effluents reuse is becoming necessary in arid regions. Produced water generated in oil and gas exploration is a promising stream for this purpose, since remarkable quantities are available. In order to turn desalination routes into economically attractive options, it is mandatory to choose and to optimize technologies aiming to minimize capital and operational costs. Therefore, several combinations of technologies, involving forward osmosis (FO), reverse osmosis (RO), assisted reverse osmosis (ARO), microfiltration (MF), mechanical vapor compression (MVC), and membrane distillation (MD) were simulated and optimized for different reuse destinations. Results indicated MF-RO as the cheapest route for salinities lower than 90 g/L, while FO-RO had the highest cost and could be unfeasible depending on salinity. For higher salt content, MF-ARO-RO was the cheapest alternative, followed by thermal processes (MF-MVC and FO-MVC, respectively). However, applicability of MVC depends on final water quality due to possible volatiles constraints. MF-ARO-RO process, which is a novel technology, was submitted to a retro-techno-economic analysis (RTEA) to investigate its potentialities. Although membrane parameters had minor influence, external parameters as ARO membrane cost, energy cost and interest rate play important roles on process cost.