Sequencing batch reactor technology: An old technique successfully applied to the treatment of pulp and paper mill effluents containing high residuals of sulphite

Stone-Consolidated Corporation (S-C C.) owns and operates eight newsprint and specialty mills in North America and in U.K.. In order to meet the September 1995 deadline of the revised pulp and paper mill regulations imposed on Quebec mills, sequential batch reactor technology (SBR) has been selected as the treatment at the four S-C C. Quebec mills. This paper will review treatment performance at the Laurentide mill only. This facility operates a very high yield sulphite pulp mill (VHYS) with no liquor recovery and as it is very well known, sulphite residual in the effluents creates additional challenges as experienced by others operators.((1,2,3)) Results to date clearly indicate that the choice of this treatment technology was excellent. After more than a year of continuous operation, compliance with TSS, BOD5 and toxicity limits has been achieved and has even surpassed expectations. The technology has proven to be very robust, easily adjustable to varying loads and highly reliable for control of the filamentous bacteria generally associated with sulphite mill effluents.