For the P.H. Glatfelter Company's Spring Grove, Pennsylvania mill, the need to eliminate sodium hypochlorite bleach from the mill's four stage bleach plant was dictated by U.S. EPA's proposed Cluster Rules. Having recently completed a large, environmentally driven pulp mill modernization project, the mill was not anxious to incur additional capital expense for another primarily environmental undertaking. Thus, a project was initiated to evaluate low capital options which would allow the mill to comply with the proposed regulations.The elimination of hypo presented a difficult challenge for several reasons. The ability to use existing equipment without incurring significant capital expense limited the chemistry options. Because the mill is situated along a very small receiving stream and is required to meet an in-stream color standard, the need to maintain or improve effluent color was also a concern.The project originated as a lab study designed to evaluate the feasibility of using hydrogen peroxide to replace bleach on the mill's pine fiber line while maintaining acceptable effluent color. Success widened the scope of the project to include full scale mill trials on both the pine and hardwood fiber lines. Replacement of hypo with peroxide has resulted in significant improvements in both pulp and effluent quality at comparable operating costs, and has positioned the mill to be in compliance with the proposed Cluster Rules.
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