Technology for recovery of spent caustic from alkaline cleaning operations in metal finishing industry
Veolia Water Solutions & Technologies (VWS) has introduced a proprietary technology for recovery of spent caustic from alkaline cleaning operations in the metal finishing industry.
VWS’ CeraMem ceramic ultrafiltration technology recovers 95 to 99% of the spent caustic solution from the cleaning section, thereby reducing waste treatment requirements and hauling volumes to 1 to 5% of the original treatment and hauling effort, resulting in significantly reduced costs for steel finishing operations, the company said.
VWS installed a caustic recovery system utilizing the proprietary technology for alkaline cleaning at a major US-based finishing mill in January 2010, with only minor equipment modifications needed to adapt the line to the new operation. The system removes oil and grease, suspended solids, metals and other contaminants from the spent alkaline cleaner, producing a regenerated cleaning solution that requires minimal chemical make-up to enable reuse in the process. The recovered cleaning solution is fed into the cleaning section tanks with a small amount of caustic and additives added to make up for losses in the process. Since commissioning of the system in February 2010, the system has successfully operated in excess of the design recovery rate with no drop in line quality.
VWS said the benefits of the CeraMem system include savings from significantly reduced make-up cleaner usage, savings from significantly reduced spent caustic treatment and waste hauling fees, excellent metal surface cleaning section tank performance and considerably reduced handling in the alkaline cleaning process. VWS supplies treatment systems and chemicals for various steel industry applications including alkaline cleaning operations, supply water, make-up water, cooling tower blowdown, wastewater and recycle/reuse.