Use of Cost-Effective Chemical and Biological Tests for the Estimation of the Environmental Impact of Bleaching Plant Effluents, 1992 Environmental Conference Proceedings

A combination of chemical analyses and small scale biological tests have proven to be successful when ranking the environmental impact of bleaching plant effluents. The parameters for the chemical analyses were mono- to tetra chlorinated phenolics, extractable organochlorines (EOCI) and AOX. The chlorinated phenolics are toxic compounds which can also serve as indicators of the degree of chlorination in the organic material. EOCI is considered to be a more relevant parameter than AOX, the latter being included due to requirements set by regulatory bodies. The EOCI values are also related to corresponding log Pow values since this parameter is generally utilized for estimating the bioaccumulation tendency.

The biological tests carried out were acute toxicity on crustaceans (’Ceriodaphnia’), growth inhibition on the green alga ’Selenastrum’ and a modified Microtox test.

About three litres of bleaching plant effluents are sufficient for the tests, making this combination particularly suitable for small scale laboratory experiments. The combination has been evaluated using effluents from laboratory bleaching with chlorine dioxide at different substitution levels and then applied to mill effluents.