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Kentucky Division of Water Releases Draft KPDES General Permit for Stormwater Discharges Associated with Industrial Activity


On September 13, 2012 the Kentucky Division of Water (DOW) released the draft General KPDES Permit for Stormwater Discharges Associated with Industrial Activity, KPDES Number KYR00.  Kentucky has been without a general permit since the previous KYR00 expired in September 2007.  The purpose of the KYR00 permit is to provide coverage for those industrial facilities in the SIC Codes specified in the definition of “stormwater discharges associated with industrial activity” that do not possess an individual KPDES permit. 

The prior version of KYR00 did not contain numeric effluent limitations applicable to all industrial activity.  Rather, the prior General KPDES Permit imposed monitor-only requirements for total suspended solids (TSS), pH, oil and grease, and chemical oxygen demand while also requiring the permittee to monitor for any pollutant limited in an effluent guideline to which the facility was subject under Federal Categorical Standards.  Under the effluent guidelines, EPA has divided stormwater dischargers into 29 industrial sectors and set effluent limitations specific to the activities routinely conducted within the sectors (e.g. Landfills and Land Application Sites, Coal Mining and Coal Mining-Related Facilities, Chemical and Allied Products Manufacturing). 

Industrial facilities that are subject to a national effluent guideline for stormwater would not be eligible for coverage under the draft KYR00 permit.  Facilities discharging to a stream subject to a TMDL for suspended solids would also not be eligible for coverage under the General Permit.  For existing eligible facilities, a notice of intent (NOI) to obtain coverage would have to be submitted regardless of whether the facility had coverage under the prior General Permit.

The draft General KPDES Permit does not address specific categories of facilities but rather serves as a nondescript catchall permit for facilities that are not required to obtain an individual KPDES Permit.  Due to diversity in eligible facilities and the number of activities conducted onsite, DOW states in the Fact Sheet that extreme variability exists in the type of potential pollutants and volume, quality, and management of stormwater.  To combat this variability, the general permit contains a combination of non-numeric and numeric effluent limitations and monitoring requirements.

Specifically, the draft KYR00 permit proposes numeric effluent limitations for TSS, pH, and oil and grease.  TSS discharges are limited to a daily maximum of 60 mg/l and a monthly average of 30 mg/l.  Oil and grease discharges are limited to a daily maximum of 15 mg/l and a monthly average of 10 mg/l.  A pH range between 6.0 and 9.0 is also proposed.  Twice per year monitoring is proposed.  DOW’s justification for the effluent limits is set forth in the Fact Sheet.

In addition, the draft General KPDES Permit requires implementation of best management practices (BMPs), development of a Stormwater Pollution Protection Plan (SWPPP), regular inspections of BMPs and reports for each inspection, and follow-up corrective actions.  The draft General KPDES Permit also specifies the required content of SWPPPs.

The proposed numeric effluent limitations may pose a potential problem for certain facilities that have not historically utilized retention basins for sediment control.  The proposed effluent limitations for some facilities would be more stringent than would be imposed under EPA’s 2008 General NPDES Permit for stormwater runoff from industrial sources.  That may run afoul of KRS 224.16-050(4), which prohibits DOW from including more stringent limits in a permit than would be imposed by EPA if it were issuing the permit.  Public notice of the draft permit began September 14 and comments are due by October 14.

To view a complete PDF of the July/August 2012 issue of the Environmental Letter, click HERE.

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