EMISSIONS OF HYDROCHLORIC-ACID, PCDD AND PCDF FROM THE COMBUSTION OF CHLORINE-CONTAINING KRAFT PULP-MILL BLEACH PLANT WASTE

The objective of this work was to determine if combustion of chlorine- containing bleach plant waste causes emissions of hydrochloric acid, p olychlorinated dibenzo-p-dioxins, (PCDD) and polychlorinated dibenzo-f urans (PCDF). Small additions of chlorine-containing bleach plant wast e to normal black liquor feed stock did not result in detectable incre ases HCl emissions during incineration. Large additions (greater than or equal to 10% by weight of solids) increased HCl emissions, possibly as a direct result of organochlorine combustion. The total PCDD/F in flue gas increased by a factor of ten with a 1% addition of bleach pla nt concentrate to black liquor. Comparisons of emitted PCDD/F and feed liquor PCDD/F indicated a net formation of PCDD/F during combustion. The emissions of PCDD/F may be a significant factor detracting from th ermal destruction of mixtures of chlorine-containing bleach plant wast e and black liquor in a standard recovery furnace.