Management of reverse osmosis concentrate by solar distillation

Abstract

Disposal of rejected brine is a fundamental part of reverse osmosis desalination technology, it presents negative influences on the marine ecosystem due to the high salt content and the presence of other harmful chemicals in the concentrate. Solar distillation is a promising technology for brine management. The main goal of this study was to treat high salinity solution of reverse osmosis desalination brine and to recover valuable resources while producing freshwater. The implementation of the study is through two phases: the first phase includes desalination by a reverse osmosis process to produce fresh water and the concentrated brine, while the second phase consists of recovering solid salts using the solar distillation. Thus, different experiments of desalination by reverse osmosis pilot and solar distillation were carried out under optimal experimental conditions. The obtained results showed that chlorides are the most dominant constituents in the composition of brines, while the daily water productivity contributed to around 80% of the total productivity of the solar system (volume of the water produced/m2/day) and the amount of salt crystallized by solar distillation represents 35 grams per liter of brine, this salt is greatly demanded in several sectors such as agriculture, industry, and others. HIGHLIGHTS Produce concentrated brine by the reverse osmosis desalination process.; Provide and test the technical feasibility of recovering reject brine using solar distillation.; Achieve zero liquid discharge and reduce the environmentally negative effects of brine on the ecosystem.; Define the influence of the optimum operating parameters.; Recover salt crystals of NaCl.;

Keywords

• environment
• seawater reverse osmosis brine
• solar distillation
• solid salts