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Activated Sludge Treatment of Kraft Mill Effluents from Conventional and Oxygen Bleaching

1991; Pergamon Press; Volume: 24; Issue: 3-4 Linguagem: Inglês

10.2166/wst.1991.0499

1996-9732

J. Nevalainen, P. Rantala, J. Junna, Reino Lammi,

Soil and Water Nutrient Dynamics

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. 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 %. 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.