New Methods for Reducing the Toxicity of Kraft Mill Bleachery Wastes to Young Salmon
Kraft pulp mill bleachery effluents and those from the unbleached screening operation were tested, separately and in combination in the proportions as they would exist in the main effluent of a particular mill, for toxicity to young Atlantic salmon, Salmo salar.The bleachery component from the chlor...
| Published in: | Journal of the Fisheries Research Board of Canada |
|---|---|
| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1966
|
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/f66-075 http://www.nrcresearchpress.com/doi/pdf/10.1139/f66-075 |
| Summary: | Kraft pulp mill bleachery effluents and those from the unbleached screening operation were tested, separately and in combination in the proportions as they would exist in the main effluent of a particular mill, for toxicity to young Atlantic salmon, Salmo salar.The bleachery component from the chlorination stage, tested under neutral pH conditions, was considerably more toxic than the other components.Major reductions in the toxicity of the chlorination stage component were accomplished by treating it with small quantities of sulphur dioxide. Lesser but still appreciable toxicity reductions were observed in the whole effluent when the chlorination component was thus treated before combination with the other components.The toxicities of laboratory-produced filtrates from certain modified first-stage (chlorination) bleaching procedures were also evaluated. Notably, much less toxic filtrates resulted when substantial mixtures of chlorine dioxide and chlorine were substituted for the normal chlorine dosage in the first bleaching stage.A number of other treatments, methods, and their relative effectiveness are discussed. |
|---|