Caustic Recovery Plant for textile processing

We are trying to find a solution to treat effluent generated from the mercerizing process in the textile industry. The caustic soda (NaOh, also known as sodium hydroxide or lye) is the major issue. The concentration of caustic soda is up to 8%. People use evaporators to get its concentration up to 22% for its recycling. But the operating cost is very high due to the use of steam. Can somebody suggest us a Low Operating Cost Technology for caustic laden waste of 50 KLD ?