Abstract A facultative hybrid reverse osmosis (RO) – pressure retarded osmosis (PRO) system can switch its operation between i) RO mode, where high quality water is produced from waste-water treatment plant effluent and ii) PRO mode, where the salinity difference between seawater desalination brine and wastewater is converted to energy. This system takes advantage of fluctuating energy pricing, by consuming low cost energy to produce water and producing high value energy. The system was modeled by a local concentration polarization and solution diffusion model, considering several geometries. The system was optimized and for different ratios of the economic value of electricity vs water, to find process settings and switch points. A necessary condition for the feasibility of the facultative hybrid RO-PRO concept is that the permeate value satisfies: i) low enough, to justify electricity production and ii) high enough, to justify water production. With a maximum energy price of 0.25 USD/kWh, the first condition translates into

中文翻译：

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兼性混合 RO-PRO 概念可提高 PRO 的经济性能：可行性和效率最大化

摘要 兼性混合反渗透 (RO) - 压力延迟渗透 (PRO) 系统可以在 i) RO 模式（从废水处理厂出水产生高质量水）和 ii) PRO 模式（其中盐度差异）之间切换其操作海水淡化盐水和废水之间转化为能源。该系统利用波动的能源价格，通过消耗低成本能源来生产水和生产高价值能源。该系统由局部浓差极化和溶液扩散模型建模，考虑了几种几何形状。该系统经过优化，并针对电与水的经济价值的不同比率，以找到过程设置和切换点。兼性混合 RO-PRO 概念可行性的一个必要条件是渗透值满足：i) 足够低，证明发电是合理的；ii) 足够高，证明水生产是合理的。最高能源价格为 0.25 美元/千瓦时，第一个条件转化为