Hydrophobic pervaporation for environmental applications: Process optimization and integration

The focus of this paper is on the design pervaporation units for wastewater treatment taking into account technical, economic, and enviromnental aspects. Two different sized industrial wastewater streams of water-chloroform, and of water-methyl-isobutylketone (MIBK) are considered. Based on a wastewater stream of 1,500 kg/d, a semi-batch process combining pervaporation with a decanter recycle loop is developed. Using this process, it is possible to recover over 99% of the organic components at concentrations of more than 98 wt.%. The treatment costs are between 0.11 to 0.16 $/kg wastewater. For the treatment of a wastewater stream of 1,000 kg/h, pervaporation combined with a decanter and recycling loop, as well as integrated in a hybrid process with adsorption, is considered. For MIBK, pervaporation with a decanter is the most attractive option taking economic and environmental aspects into account, while, for chloroform, the hybrid process is the better option. Treatment costs in all cases are about 0.03 $/kg wastewater. The recovery rate of the organic compounds is over 99% at concentrations over 98 wt. %. The authors concluded that pervaporation as a stand-alone unit, or integrated into hybrid processes, offers significant advantages over conventional alternatives.