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Industrial Wastewater Pretreatment Program
The Warwick Sewer Authority (WSA) established an Industrial Pretreatment Program (IPP) back in the early 1980’s as required by the Federal Government through the provisions of the General Pretreatment Regulations (40 CFR Part 403). The mission of the IPP is to protect our sewer collection system, treatment facility, Pawtuxet River and Narragansett Bay by preventing the discharge of toxic pollutants and excessive conventional pollutants from the industrial/commercial user base. The permitting of industrial and commercial businesses is the most effective way of making companies aware of the surveillance conducted by the WSA. Maintaining a compliant user base is accomplished through the issuance of wastewater discharge permits for all Warwick based industrial and commercial facilities discharging wastewater, either directly or indirectly (via septage hauler), to the Warwick Sewer System. Ultimately, it is the IPP’s goal is to strive to eliminate the release of toxic and conventional pollutants into the collection system/environment through a cost effective and environmentally sound program. There currently are 643 permitted businesses in Warwick regulated by the IPP. These include 301 Industrial/Commercial users, 340 Food Service Establishments and 2 Septage Haulers. Of the 301 Industrial/Commercial users, 9 are classified as Significant Industrial Users (SIU) based on the following criteria:
Any User subject to Categorical Pretreatment Standards under 40 CFR 403.6 and 40 CFR Chapter I, Subchapter N (2);
Any User discharging an average of 25,000 gallons per day or more of process wastewater to the Warwick Sewer Authority or contributing a process wastestream which makes up to five percent (5%) or more of the average dry weather hydraulic or organic capacity of the Treatment Facility;
Any user that has a reasonable potential, in the opinion of the Authority, to adversely affect the operation of the Treatment Facility and/or to violate any Pretreatment standard(s) or requirement(s).
A staff of four full-time personnel manage the program. WSA personnel monitor the incoming wastestream (raw influent) to the WWTF on a 24-hour per day basis to ensure that elevated levels of pollutants, in excess of permitted levels, are not present. Should monitoring demonstrate elevated levels of pollutants, IPP personnel will deploy 24-hour sampling devices in select manholes throughout the City in order to determine the origin of the elevated pollutants. Non-compliant discharges are traced back to the business in violation of their permit discharge limits and enforcement action ensues. Where non-compliance has been detected within the industrial base, the Enforcement Response Plan has provided for an essential fining mechanism, which acts as a deterrent to repeat violations.
Routine permittee inspections and monitoring/sampling events are regularly conducted and tracked by hard copy reports and electronic data entry. Over 70 permittees have regularly scheduled sampling events to ensure they meet our local limits. The frequency at which these events are scheduled is driven by the permittees' potential to impact the collections system and our treatment facility. More frequent inspections may be conducted where sampling events indicate elevated or non-compliant pollutant results.
The total metals concentration of the incoming wastestream to the WSA has been reduced from approximately 1.85 mg/L (1986) to approximately 0.20 mg/L (2022). This is a testament to the effectiveness of the Industrial Pretreatment Program and the application of local limits (LLMP). Wastewater discharge limits, as derived from ongoing local limits evaluations, maintain headworks loadings that facilitate optimum treatment conditions within the plant. Optimum treatment conditions have indeed provided for an effluent compliant with RIPDES effluent limitations.
Warwick Sewer Authority