Flocculation as an analytical pre-concentration step and regeneration

It was found that addition of flocculating agents led to the particle binding of the majority of resin acids and species contributing to colour and BOD. Based on results obtained for pond 1 water samples, it was proposed that flocculation followed, by filtration, might provide a useful means of treating Tasman's primary effluent. A local supply of pumice was available to provide a low cost filtration medium. The significance of pumice grain size was assessed in experiments in which a dose of PFS (20 mg/L) was utilised. The greatest removal of flocculated resin acids, colour and BOD5 from pond 1 water was achieved using 0.85 mm pumice. The finding that resin acids could be successfully recovered from flocs prompted the hypothesis that it might be possible to design an analytical technique based on pre-concentration (by flocculation) of the low levels of resin acids in highly diluted receiving water samples, by extraction of the resolublised floc, rather than extraction of the receiving water sample.