Wastewater from industrial processes poses a significant threat to water quality and aquatic wildlife:
(1) Heavy metals and some organic chemicals which are contained in many industrial wastewater discharges are not neutralized or removed by the biological treatment process used at most municipal wastewater treatment plants, including Shreveport's two plants. Accordingly, chemicals and pollutants which are discharged to the City's sanitary sewer system can "pass through" the City's plants and be discharged into the Red River (or become entrained in sewage sludge, which presents disposal issues and prevents the sludge from being beneficially used).
(2) In addition, chemicals from industrial discharges pose a threat to the beneficial bacteria which are used at the City's plants for treating domestic sewage. Thus, untreated industrial discharges can actually result in improperly treated domestic sewage, and can result in significant repair and maintenance costs for the City.
(3) Finally, discharges high in oil and grease content can result in clogs and backups in the City's sewer collection system, causing potential overflows of sewage on the ground and damage to city lines and pumping equipment. Discharges from restaurants and other facilities with high grease levels in their waste product can cause these types of problems.
Proper "pretreatment" of a waste stream before it is discharged to the City's sanitary sewer system prevents these problems.
Currently, there are approximately 25 Significant Industrial Users (SIUs) which discharge industrial wastewater into Shreveport's sanitary sewer system. Numerous restaurants also discharge their graywater into the sanitary sewer system.
Each of these users has a permit issued by the City which allows the discharge, provided that certain requirements are met (including regular monitoring, reporting, and proper operation of the pretreatment system).
Main Objectives of the City's Pretreatment Program
• Protect the city's wastewater treatment plants
• Protect the health and safety of the workers at these facilities
• Protect the sewer collection system
• Prevent plant interference and pass through
• Prevent non-compliance with the terms of the City's wastewater discharge permits
• Protect receiving waters
• Enhance bio-solids reuse and water reclamation