Municipal System Overview and Description

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 676 permitted businesses in Warwick regulated by the IPP. These include 376 industrial/commercial users, 281 restaurants/food preparers and 19 septage haulers. Of the 376-industrial/commercial users, 14 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 two full-time persons and one half-time person manages 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 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.

The total metals concentration has been reduced from approximately 1.85 mg/L (1986) to approximately 0.24 mg/L (2005), a testament to the effectiveness of the program and the application of local limits (LLMP). Wastewater discharge limits, as derived from ongoing local limits research, 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.

Where non-compliance has been detected within the industrial base, the ERP has provided for an essential fining mechanism, which has certainly acted as a deterrent to repeat violations. Over the past reporting period, the WSA has, in good faith, allowed for two of our SIU’s to defer payment of fines and instead use the fine monies to upgrade their systems. This has provided our SIUs with an incentive to maintain compliance.

Over the past 4-5 years, the Warwick Sewer Authority has worked closely with the RIDEM Pretreatment division in revisiting and updating our Sewer Use Ordinances (SUO), Rules and Regulations (specifically Regs. 9, 10, 40, 48, 54 and 55) to be consistent with EPA requirements. Back in October 2000, our IPP had its SUO/ERP modified to indicate a maximum fine penalty increase from $5,000/violation/day to $25,000/violation/day. Additionally, within that same 3-4 year time frame, improvements (approved by RIDEM) were made to the Spill Control Plan and Permit Templates. These improvements have allowed the IPP to assist its Commercial and Industrial user base in discharging compliant wastewaters, as well as, enforce rules where non-compliance has been encountered.