WATO initiated a visit by water professionals from Bulgaria to one of the leading Water companies in Russia, Vodokanal St. Petersburg. The ultimate goal of the visit was to share the experience by the Russian colleagues with the latest technologies used in building the newest Waste Water Treatment and Potable Water Treatment Plants. One of the most interesting and attractive sites was the unique system of water quality biomonitoring - diagnostics of the functional status of crayfish and fish.