| 摘要 |
<p>A UPW plant (100) treats feed fluid having an organic nitrogen contaminant by contact with a targeted removal unit (30) to reduce a trace concentration below a threshold. The removal unit may include an enzyme or other agent, free or bound, which is specifically effective to break down the contaminant. The enzyme is preferably stabilized, immobilized or protected, such that its integrity, or at least its activity, is maintained for hours, days or longer, operating without a cofactor and with high efficiency. The system is useful for removal of urea, which impairs a self-catalyzed lithography process or a pharmaceutical preparation process. Enzyme is, for example a lyophilized/crystallized urease, may be contacted with the stream by direct injection, or may pass through a reaction tank or delay and mixing line to assure adequate contact time for breakdown or capture of the contaminant. The enzyme may be immobilized on a support, e.g. a membrane or beads, forming a bead or column or surface across which the feed flows to cleave the urea in the feed stream, or may comprise microparticles that reside in the fluid and are themselves separated and re-used. When using free or microparticle-bound enzyme, microparticle substrate may be recovered as rententate from a downstream or side loop RO (215) or other filtration unit, or may be recovered in a settling tank, and returned tot he reaction to maintain a high concentration of the enzyme or agent in operation.</p> |
