Biotreatment Of Krafi ’Mill Condensates For Reuse, 1996 Minimum Effluent Mills Symposium Proceedings

Douglas A. Barton, David B. Buckley and Steven W. Jett - NCASI

John W. Lee - CH2M Hill

Reuse of condensates is an important component of water usage and heat conservation programs in a kraft mill operation. Increasing the quantity of condensates reused and, for some reuse applications, improving the quality of the condensates via treatment, offers the potential for; (a) further reduction in water usage rates and (b) reductions in atmospheric emissions of volatile organic compounds such as methanol from unit processes at which condensates are reused. An example of the latter case may be the use of treated condensates for brown stock washer and recausticizing operations. Biological treatment of pulp mill condensates in a stand-alone treatment process potentially offers a means to recover large quantities of high quality condensates. This paper describes a conceptual design for such treatment and presents the results of an order-of-magnitude cost estimate for condensate biotreatment. The capital costs estimated indicate that for vacuum drum brown stock washer emission control biotreatment and reuse may be cost competitive with the alternative of washer enclosure and vent gas incineration. It is important to note, however, that design parameters were selected in the absence of actual performance data. Two preliminary treatability studies undertaken to initiate the development of the necessary data are described herein.