75-07: Recovery of Chromate from Cooling Tower Blowdown by Ion Exchange Resins

During the past several decades, chromate-based corrosion inhibitors were widely used in open cooling water recirculating systems. 

In 1971, the Japanese Government, however, adopted a regulation which limited the discharge of toxic matter including hexavalent chrome to public waters. Factories employing cooling systems were forced to reduce chromates to less than 0.5 ppm as Cr^6+ or replace chromates to other types of corrosion inhibitors; however, some of them could not do so because of specific system conditions.