A Lawrence man and his company, MagnaGro International Inc., have pleaded guilty in federal court to illegally discharging waste from a fertilizer operation into the city’s sewer system.

Federal prosecutors charged Raymond Sawyer, 57, and his company under the Clean Water Act. Jim Cross, a spokesman for acting U.S. Attorney Marietta Parker, said Sawyer admitted the company, 600 E. 22nd St., in March 2001 discharged a large quantity of industrial waste from fertilizer production into the city’s sewer system, which interfered with the sewer system’s operation.

The company formulates chemical fertilizers for resale across the nation. Officials with the Kansas Department of Health and Environment and city in 2001 ordered the company to stop.

In September 2007, investigators with the Environmental Protection Agency found Sawyer and the company discharging waste from the fertilizer operation into the sewer system again, using a hose inserted into a toilet stool. Investigators determined the company had been doing that for 10 years.

Sentencing will be June 1. Sawyer faces a maximum one year in federal prison, plus a fine up to $25,000 per day of the violation. The company faces a possible fine of $50,000 or more per day of the violation.