Volatile organochlorine compounds formed in the bleaching of pulp with ClO2

Volatile organochlorine compounds (VOCCs) formed during kraft pulp bleaching were determined from the bleaching effluent at the bleach plants and from waste water at the waste water treatment plants of three pulp mills means by of a purge and trap injector connected to a GC/MS. Among the seventeen VOCCs identified when ClO2 was used in pulp bleaching, chloroform constituted the major fraction and dichloroacetic acid methyl ester and 2,5-dichlorothiophene were also abundant. The formation of VOCCs was related to the use of ClO2 in bleaching, with a lower ClO2 charge yielding less VOCCs and hardly any being formed when non-chlorinated bleaching agents were used.