Laboratory testing Membrane distillation / crystallization phase 1

VA TECH WABAG is investigating the application of membrane distillation (MD) for water and wastewater treatment. As a result of lab-scale and pilot tests, concentrating of high sa-line wastewaters was identified as the most promising field of application. The main ad-vantages of MD are the practical independence from osmotic pressure and the high distillate quality. However, like all concentrating processes, MD is limited by the solubility of the dissolved salts. In the case of „zero-liquid-discharge“-concepts, MD is only part of the solution. Nevertheless, with the combination of MD and crystallization using the seeding process, MD could be applied as the final step for zero-liquid-discharge. With the first and second phases of laboratory tests, the principal feasibility could be proved for different salt solutions and two different wastewaters.