【1. Evaluation of PRO power generation system using various PRO membrane modules】

　Pressure retarded osmosis (PRO) has been regarded as one of the emerging power generation systems from renewable energy resources. In a PRO process, water transport from a solution with low salt concentration to a pressurized solution with high salt concentration through a semi-permeable membrane can generate the electric power by using a hydraulic turbine. In our lab, a systematical evaluation has been performed by using various types of PRO modules.

【2. Evaluation of PRO performance using various PRO membrane】

　One of main problems in PRO is internal concentration polarization (ICP). The ICP is caused by salt accumulation in the porous support layer and therefore it results in the unfavorable reduction of the osmotic pressure difference across the PRO membrane. To reduce this ICP effect, the porous structure of the support layer is much important. In our lab, we have investigated the effect of membrane types on the membrane performance under PRO operation.

【3. Evaluation of membrane fouling in a PRO system】

　To achieve the commercialization of PRO, how to prevent the membrane fouling should be concerned. Because the membrane fouling leads the unfavorable reduction of the PRO membrane performance and the subsequent power generation performance. Although pretreatment process would be installed before the PRO system, such pretreatment process would results in the higher operational cost. In our lab, we have investigated the effects of solution properties and operating condition on the fouling behavior under PRO operation by using commercially available PRO membranes.