Evaluation of integrated membranes for tastes and odours and algal toxin control

Cyanobacteria and actinobacteria inhabit natural water sources. When they bloom, their very high numbers reduce water quality. These microscopic single-cell organisms produce toxins as part of their normal metabolism, and if the individual cells are damaged or broken, the toxins are released into the water, which makes them difficult to remove. Three of the most problematic toxins are ‘cylindrospermopsin’, which poisons the liver, ‘MIB’ (methylisoborneol) which makes water smell musty, and ‘geosmin’, which gives water an earthy taste. In this research project one chemical ‘sieve’ (reverse osmosis, RO) and two types of physical ‘sieves’ were used to filter the nuisance cells and their products out of water. The three processes (RO, ultra and nanofiltration) were also tried in various combinations to identify an integrated filtration and membrane system that best prevented damage to the cells, minimised leakage of nuisance compounds into water, and maximised the removal of cells, toxin and taste and odour compounds.