The paper describes a unique system designed for a large well-established chemical plant. The plant has been in operation for many years and was responsible for fouling the municipal receiving sewers. Field surveys indicated that local downstream sewers had been heavily coated as a result of the flocculation and sedimentation of the effluent wastes within the municipal sewer lines. It manufactures a variety of organic chemicals used in paint additives, coatings, oils, and plastics with wastewater flow averaging 39,000 gallons per day. The wastewater pretreatment system has been designed to remove fouling materials and prevent sewer stoppages.