Microbiological Control of an Ultrafiltration System Used in the Recovery of Dilute Waste Coating, 2000 Papermakers Conference Proceedings

Margaret M. Palcic, James G. Smith, Dave Abercrombie, Adam Glowacki--Ultrafiltration (UF) systems for the recovery of dilute waste coating are prone to microbiological fouling that can adversely impact the performance of the process. Controlling this contamination presents a challenge to all the people involved in the operation of the UF system, including the mill, biocide supplier, and UF system supplier. If fouling occurs it can result in decreased quality of the permeate and recovered coating, decreased operating efficiency of the system, and the degradation and destruction of the UF membranes. A Canadian LWC mill has been successfully using an UF unit since 1996. A great effort was made to minimize 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 are 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.