Description:
<jats:p>Conventional and oxygen bleaching effluents from hardwood kraft pulp mills were treated in laboratory-scale activated sludge processes. The main interest was the fate of organochlorine compounds in the activated sludge process.</jats:p>
<jats:p>In the treatment of conventional bleaching wastewaters the BOD7-reduction was 80-91 % and in oxygen bleaching wastewaters 86-93 %. The respective CODCr removals were about 40 % and about 50 %.</jats:p>
<jats:p>The AOX reductions were on average 22 % and 40 % in the treatment of conventional and oxygen bleaching effluents, respectively. The reductions of chlorinated phenols, guajacols and catecols were usually more than 50 % in both reactors. Very little accumulation of AOX into the sludge was observed. The stripping of AOX from aeration unit was insignificant.</jats:p>