Use of an Anaerobic Fluidized Bed Reactor in the Treatment of a Closed Process Water Circuit in Secondary Fiber Mills, 1994 Environmental Conference Proceedings

Partial or complete closure of white water circuits in waste paper mills will result in an increased concentration of organic contamination which leads to reduced effectiveness of polymer additives, and deterioration of the mechanical properties of the produced paper.

A pilot study at a paper mill which produces corrugating medium from waste corrugated board, demonstrated that by inserting an anaerobic fluidized bed reactor in the closed water circuit, it is possible to deconcentrate the organic pollution present in the circuit. Results of the 3.5 cu.ft. (0.1 cu.m) fluidized bed pilot plan demonstrate a COD removal of 42 to 64 percent.

This paper examines the effect of reduced COD in the white water on the paper making process. In the pilot study, as COD decreased, the strength properties of paper increased. The average gain on bursting strength was 20 percent. COD removal also resulted in a potential decrease in the consumption of cationic polymer used for sheet formation.

Data from this pilot study has been used in determining the design of an industrial scale installation at the Lecourseonnois paper mill located near Paris, which also manufactures corrugating medium. A continuous purge from this water circuit is treated in a 4.5 m diameter fluidized bed reactor. Effluent from methane fermentation is then recycled back to the mill.

The scale-up of pilot results to the industrial design of this full-scale plant, as well as potential cost savings from anaerobic treatment, are reviewed.