REVERSE OSMOSIS ENHANCED RECOVERY HYBRID PROCESS

摘要

Disclosed is a high-recovery integrated recycling process to treat water and waste water having high hardness, silica, and other contaminants to facilitate operation of a reverse osmosis (RO) membrane at very high overall recovery when treating waste water containing high concentration of sparingly soluble inorganic salts like hardness, silica, and other components such as silica, etc. The RO membrane continuously operates in low or conservative recovery conditions, but can still achieve a very high overall system recovery. The process includes precipitation softening in a softening clarifier where the scale forming salts are reduced followed by filtration and reverse osmosis. The precipitated salts are removed as underflow from the clarifier. The softened or partially softened water is then filtered by a conventional filtration system, for example by a media filter. This is then fed to a reverse osmosis membrane unit that is designed to operate at an appropriate recovery to avoid scaling and fouling. Normally the recovery can be maintained quite low, for example at 50 to 60% of the feed flow.