Laboratory-Scale Investigations of Algal Toxin Removal by Water Treatment

The paper describes some water-treatment processes which have been investigated on a laboratory and pilot-plant scale for their effectiveness in removing toxic algal cells and the dissolved toxins microcystin-LR and anatoxin-a. Oxidation with ozone or potassium permanganate, or treatment by biological activated carbon, were found to be the most effective processes for removal of the dissolved toxins. Chlorination was effective only for the removal of microcystin-LR. Toxins, contained within algal cells, could be removed effectively by coagulation, clarification and filtration under suitable conditions. Consideration of the structure and properties of micro-cystin variants suggests that treatments which are suitable for removal of microcystin-LR and anatoxin-a should be suitable for removal of other microcystins.