A Comprehensive Study of Membrane Distillation: Membrane Development, Configuration Assessment and Applications

Promovendus/a: Lies Eykens

Promotor(en): Prof. dr. ir. Bart Van der Bruggen, Luc Pinoy, Dr. Ir. Chris Dotremont, Dr.Ir. Kristien De Sitter

Almost one third of the world's population deals with water scarcity or bad water quality. Therefore, regulations on water discharge and treatment are becoming stricter in the future. The classical desalination techniques are limited in salinity. In contrast, membrane distillation can operate up to saturation. Therefore, the technique is interesting for numerous applications involving highly concentrated dissolved components. The process can be focused on production of pure water, but also on the recuperation of valuable solutes. Membrane distillation uses a hydrophobic porous membrane, through which only vapor can migrate. The dissolved components are concentrated in the feed stream. The driving force for vapor transport is the temperature difference (= vapor pressure difference) over the membrane. In this PhD, the performance of the current commercial membranes was evaluated and an optimal membrane structure was defined. Based in this knowledge, a novel membrane production strategy was developed. In the final part, case studies were explored to evaluate the potential of membrane distillation. It was shown that membrane distillation was technically and economically viable for the treatment of pickle brines from the cheese industry. The critical view on the process, the development of a novel membrane and the feasibility studies for novel markets are important steps towards commercialization of the technology. Yet, future pilot testing in real environment and scaling up are still crucial before membrane distillation will be applied on industrial scale.