SLUG LOAD OF ETHEANOL TO THE POTW. THIS DISCHARGE OF ETHANOL WAS TOXIC TO THE ACTIVATED SLUDGE IN THE CITY'S PRETREATMENT SYSTEM AND BIOTOWERS. THIS DISCHARGE RESULTED IN AN UPSET TO THE CITY'S TREATMENT FACILITY AND RESULTED IN VIOLATIONS OF THE CITY'S NPDES PERMIT FOR CARBONACEOUS BIOCHEMICAL OXYGEN DEMAND IN MAY 2006.