Protection of Ultrafiltration Waste Coating Recovery System from Microbiological Contamination, 2000 Coating Conference Proceedings

M. M. Palcic, D. Abercrombie, J. G. Smith, A. Glowacki--Ultrafiltration (UF) is a membrane separation process that can be used to remove excess water from dilute waste coating. These systems are prone to microbiological fouling that can adversely impact the performance of the recovery process and the life of the membranes. Controlling contamination presents a challenge to all the people involved in the operation of an UF system, including the mill, biocide supplier, and UF system supplier. A Canadian lightweight-coated papermill has been successfully using an UF unit for coating recovery since 1996. A great effort has been made to minimize microbiological contamination throughout the coating kitchen and UF process. This required a concerted effort on the part of the papermaker, the biocide supplier, and the UF system supplier to ensure that the process operated efficiently. This team developed a microbiological control program that minimizes contamination in the coating additives, formulated coating, and the various tanks of the UF system. Several parameters were closely monitored in the process including microbiological levels, process pH, biocide feeds, and biocide effectiveness. The result of this effort is a coating recovery system that has performed effectively since startup.