A bus driver for the Dave Matthews Band (search) pleaded guilty Wednesday to charges stemming from the dumping of 800 pounds of human waste from his vehicle's septic tank onto a sightseeing boat on the Chicago River (search).

Stefan Wohl (search) was sentenced to 18 months probation and 150 hours of community service, said Tom Stanton, a spokesman for the Cook County state's attorney's office. He also was fined the maximum of $10,000, which will be paid to Friends of the Chicago River, a conservation group

Wohl, 42, of Selma, Texas, was charged with reckless conduct and discharging contaminates to cause water pollution.

Authorities said that on Aug. 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. The boat immediately returned to its dock and was disinfected. The Chicago Architectural Foundation, which operates the tour, offered refunds to the 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 cooperated in the investigation, including bringing the bus, one of a number used by the band, back to the city for inspection, authorities said.

The band has since donated $50,000 to the Friends of the Chicago River and $50,000 to the Chicago Park District.

A lawsuit filed by Illinois Attorney General Lisa Madigan against the band and Wohl is pending. It seeks $70,000 in damages.