The proper selection and use of a wet end biocidal treatment program is a key element in a paper mill’s effort to optimize efficiencies in the face of technological changes. With increased emphasis on the use of recycled paper, changes in papermaking chemistry from acidic to alkaline, efforts to reduce water use and consumption, and the ability to control microorganisms and associated problems has become even more critical. Modern biocidal treatment programs seek to achieve the performance of the ideal biocide that is cost effective, fast acting, broad spectrum in efficacy and applicability, environmentally friendly, and low in toxicity. Oxidizing biocides meet these requirements.
Hydantoin stabilization technology was developed to achieve the advantages of oxidants in the high oxidant demand environment of papermaking applications. Specifically, it was discovered that 5, 5-dimethylhydantoin (Equinox® Stabilizer, DMH) dramatically improves bactericidal and slimicidal efficacy of NaOCI solutions in pulp slurries, significantly reducing the amount of NaOCI required to achieve biological control. As a result, a safe and non-toxic formulation of Equinox® Stabilizer was developed which, when combined with NaOCl, reduces chlorine’s normal tendency towards unselective oxidation and, thus, increases its slimicidal efficiency. This technology is described in detail in US Patents 5.565.109. 6.429.181. and 7.407.590 [1 – 3]
The benefits of hydantoin technology results from the conversion of free chlorine to stabilized chlorine, which effectively increases the lifetime of active chlorine in the presence of organic components and contaminants.
The results of several laboratory and field evaluations of Equinox® Stabilizer technologies in papermaking and cooling water applications were previously published in technical literature and demonstrated the following benefits [4 – 11]:
- stabilization and efficacy enhancement
- biofilm efficacy
- compatibility with additives
- absorbable organic halides (AOX) reduction
- benign toxicological profile
- excellent cost performance and
- cost-effective field performance.