| 摘要 |
A process for treatment of water. Hardness and non-hydroxide alkalinity are removed from feedwaters in amounts to substantially avoid scaling when concentrated. Sparingly ionizable components in the feedwater are urged toward increased ionization by increasing the pH of the feedwater, and, in an embodiment, up to about pH 10.5, or higher. In this manner, species such as silica become highly ionized, and (a) their rejection by membranes used in the process is significantly increased, and (b) their solubility in the reject stream from the membrane process is significantly increased. Sparingly ionized species such as boron, silica, and TOC are highly rejected, and thus, their passage through the membrane is reduced by a factor of ten or more. Recovery ratios of ninety percent (90%) or higher are achievable with many feedwaters, while simultaneously achieving a substantial reduction in cleaning frequency of membranes used in the process. |
