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Biological Treatment of Bleach Waste 

 Containing Added Chlorinated Catechol 



In order to determine whether tetrachlorocatechol woiild be 

 oxidized dviring biological treatment, a known amount of this 

 compound was added to bleach waste undergoing biological treatment. 

 The mixture was then bioassayed to evaluate tetrachlorocatechol 

 oxidation. 



The bleach waste mixture used in these experiments was 

 obtained from a kraft pulp mill when the mill was making full 

 bleach pulp (orightness 89 to 92) from coniferous trees. The 

 mixture consisted of the following components; caustic bleach 

 waste (24., ^ per cent), acid bleach waste (36.6 per cent) and wash 

 ■water from the final washing of pulp following recovery of black 

 liquor (39 per cent). This mixture was very acid, having a pH of 

 about 3, but before use in treatment or bioassay it was neutralized 

 to pH 7 to 7.4. with ION KOH (Servizi, Stone and Gordon, 1966). 



An activated sludge (heterogeneous bacterial culture) was 

 developed on neutralized bleach waste (NBW) by aerating a mixture 

 of U liters domestic sewage, U liters NBW and 200 ml of soil 

 elutriate for two successive 24-hr periods separated by settling 

 of slxidge and re-feeding. After initial development of sludge, 

 settling and re-feeding were continued for a week at 24-hr intervals 

 with NBW as the sole organic source. Sludge was supplied with 

 nitrogen and phosphorous throughout the acclimation and experimental 

 periods at the rate of BOD/n/P equal to approximately 2OO/IO/I, 



Following acclimation, 400 ml of settled acclimated slxidge was 

 separated into two equal portions and 4 liters of NBW was added to 

 one portion while 4 liters of ijBW with 3 ppm tetrachlorocatechol 

 added was fed to the other portion. The two mixtures were aerated 

 for 24. hr and then settled. Enough supernatEint was drawn off for a 



