Summary

The water industry has been actively seeking methods to control cyanobacteria. However, controlling them to a level that ensures no taste-and-odor problems is difficult. Even low numbers of cyanobacteria can produce concentrations of compounds that cause tastes and odors that attract customer complaints. The most sustainable long-term solution for reducing toxins, tastes, and odors is to control cyanobacterial growth through mixing and a reduction in nutrient levels.
The goals of this project were to investigate cyanobacterial toxin degradation in reservoirs, identify toxin-degrading organisms, and develop reservoir management approaches for the control of toxin production. Biodegradation studies were undertaken on two cyanobacterial toxins, cylindrospermopsin and microcystin. These studies consisted of spiking natural waters with known concentrations of toxin and measuring toxin degradation through time. Sand column biofilters were also spiked with microcystin and the evolution of a microbial community able to degrade the toxins was examined. The microbial community was screened, using molecular techniques, for organisms capable of degrading toxins.