Practical Use of Bromochlorodimethylhydantoin as a Slimicide for Paper Manufacture, 2002 Technology Summit Proceedings

A. D. Harrison, J. P. Sisk & P. W. Steenbeek

As paper mills move to implement more stringent water conservation policies, water reuse within the mill continues to escalate. Current microbiocides used to maintain proper control of microorganisms on paper machines are challenged to perform well in the presence of high cycled water. It is well known that hypohalous acids work well for biocontrol in most water systems (1, 2, 3, 4).

In the early 90's, a new chemistry, bromochlorodimethylhydantoin (BCDMH), was introduced as a biocide for paper mills to help reduce slime and thereby increase runnability. The product was originally introduced in tablet and granule form for raw water, shower water, and some waste water applications. In the mid-90's, powder was introduced for on-machine applications.

BCDMH originally received limited acceptance because of perceived issues with other hypohalous acid based biocides, and with powders in general, which were expected to reduce rather than enhance runnability. One major objection to hypohalous acid slimicide programs has been the known incompatibility between hypohalous acid and the polyamide fibers used in the manufacture of machine clothing (felts). Powders in general are known to have issues with flowability, dusting, and wetability, and current commercial BCDMH powder products initially experienced many of the same application issues.

Anecdotal observations were made in field applications that indicated that BCDMH did not have the expected negative effect on polyamide felts as has been observed with other hypohalous acid biocides. A series of lab studies were performed that demonstrated this lack of negative effect of BCDMH on polyamide felts when compared to NaOCl and activated NaBr.

To address application issues with powder, the BCDMH powder product has been re-engineered to provide a product with enhanced flowability, decreased dusting, and increased wetability. Both lab and field studies were performed on this new powder to demonstrate its characteristics and are presented in this paper.