A bus driver for the Dave Matthews Band has pleaded guilty to dumping 800 pounds of human waste onto a sightseeing boat on Illinois’ Chicago River. Earlier Thursday, Stefan Wohl was sentenced to 18 months probation and 150 hours of community service. He was also fined the maximum of $10,000, which will be paid to Friends Of The Chicago River, a conservation group. Wohl, 42, was charged with reckless conduct and discharging contaminates to cause water pollution. Authorities said that on August 8, when Wohl was alone in a bus used by band violinist Boyd Tinsley, he emptied the septic tank while driving across the open grating deck of the Kinzie Street bridge. The waste poured onto the open deck of the Chicago’s Little Lady tour boat, which was passing below with more than 100 passengers. Prosecutors said Wohl had denied discharging waste on the bridge, but surveillance tapes from buildings in the area were used to zero in on the bus. The band’s members, who cooperated with authorities during the investigation, since donated $50,000 to the Friends of the Chicago River and $50,000 to the Chicago Park District.