Local Limits Derivation Report
The Town Wastewater Division operates and maintains a regional wastewater treatment facility (WWTF) located on Westmoreland Street in the Town of Narragansett. The facility services portions of South Kingstown and its regional partners, the Town of Narragansett and University of Rhode Island (URI). The facility receives septage from outlying areas and conventional wastewater via the Town’s municipal gravity collection system and twelve pump stations. The Town’s collection system receives wastewater from Town properties and URI while Narragansett's wastewater flow is conveyed via a separate force main that discharges at the WWTF headworks structure.
Local Limits Evaluation
Elevated biological oxygen demand (BOD) is an evolving problem in Rhode Island and throughout the country. Since some industries typically have very high BOD discharges, RIDEM recently issued guidance documents for WWTFs to try and work with this industries while still complying with RI Pollutant Discharge Elimination System (RIPDES) permit limits that RIDEM issues to each wastewater treatment facility. Regardless of what industries may wish to discharge, the Town must comply with its RIPDES effluent monthly average limit of 30 mg/l for BOD and 30 mg/l for suspended solids.
In addition, to South Kingstown specific wastewater user flow, the Town of Narragansett (northerly area) and University of RI are also contributory to the WWTF flow and associated mass loadings that correlate to establishment and/or amendments to the local limits.
Since it has been 20+ years since a local limits evaluation has been completed, RIDEM recommended that municipal WWTF reevaluate their pretreatment local limits to determine if BOD local limits (in addition to other local limits) merit modifications. Therefore, the Wastewater Division worked with an Engineering consultant to prepare the following Local Limits Derivation Report for the Town of South Kingstown, RI. The report has been reviewed and approved by RIDEM. The Town is preparing to submit to the Town Council a revised Wastewater Management Ordinance to reflect the findings of the Local Limits Derivation Report.
Local Limits Derivation Report for the Town of South Kingstown, RI