Although membrane distillation (MD) has great potential in treating high-salinity wastewater, continuous accumulation of inorganic salt due to increasing concentration inevitably causes supersaturation and subsequent membrane scaling. Crystallizer is an effective tool used for removal of salts; however, it has been hardly applied for sparingly soluble salts. In this study, a simultaneous membrane distillation–crystallization (SMDC) system was developed for gypsum scaling control. Induced crystallization was adopted to retard the membrane scaling. The transmittance and ion concentration of the concentrate were measured to investigate the performance of the induced crystallization. The membrane scaling was characterized by both vapor flux measurements and scanning electron microscopy. Besides, the permeate conductivity was monitored to assess the membrane wetting during MD, and the energy evaluation was performed for the SMDC system during the reverse osmosis brine treatment. Results showed that the seeding of gypsum at dosage of 1 g L⁻¹ effectively restricted the membrane scaling and wetting. Although the combination of seeding and heating showed better membrane scaling control performance, the energy consumption of the SMDC system increased by 4 times without considering heat recovery. Therefore, feed seeding alone is an efficient and economical measure to restrict gypsum scaling and wetting during the high-salinity wastewater treatment using MD.

尽管膜蒸馏（MD）在处理高盐废水中具有巨大潜力，但由于浓度不断增加而导致无机盐的持续积累不可避免地会导致过饱和和随后的膜结垢。结晶器是用于去除盐分的有效工具。但是，它几乎没有用于难溶的盐。在这项研究中，同时膜蒸馏-结晶（SMDC）系统被开发用于石膏结垢控制。采用诱导结晶来延迟膜结垢。测量浓缩物的透射率和离子浓度以研究诱导结晶的性能。通过蒸汽通量测量和扫描电子显微镜来表征膜的结垢。除了，监测渗透率，以评估MD期间膜的润湿性，并在反渗透盐水处理过程中对SMDC系统进行能量评估。结果表明，以1 g L的剂量播种石膏^-1有效地限制了膜的结垢和润湿。尽管播种和加热相结合显示出更好的膜结垢控制性能，但SMDC系统的能耗却增加了4倍，而没有考虑热量回收。因此，仅饲料播种是在使用MD进行高盐度废水处理过程中限制石膏结垢和润湿的有效且经济的措施。