Rock Hill, South Carolina – The City of Rock Hill is set to host a public hearing on July 2, 2025, from 1:00 PM to 2:00 PM, concerning a proposed industrial pretreatment wastewater permit for Silfab Solar. The hearing will take place at the City Hall Council Chambers, located at 155 Johnston Street, Rock Hill, South Carolina 29730. For those unable to attend in person, a livestream of the public meeting will be available.
The proposal involves a modification to, or a proposed new, Significant Industrial User Wastewater Permit for Silfab Solar, identified as permit number SIL-060125. Silfab Solar’s facility is situated at 7149 Logistics Lane, Fort Mill, SC 29715.
The permit outlines specific effluent limitations and monitoring requirements for Silfab Solar’s non-domestic wastewater discharge into the city’s collection system. The point of compliance for these limitations is Sample Point A, after the treated process water. The permit establishes interim limits from June 1, 2025, to June 30, 2027, and final limits effective July 1, 2027. Silfab Solar is mandated to adhere to the most stringent of either local or categorical limits, with the categorical standard falling under 40 CFR Part 469.18 Electrical and Electronic Components Subpart A Semiconductor Subcategory.
Key parameters with specified discharge limits include a range of metals (Arsenic, Cadmium, Chromium, Copper, Lead, Mercury, Nickel, Selenium, Silver, Titanium), non-metals (Chemical Oxygen Demand, Cyanide, pH, Temperature, Total Dissolved Solids, Total Suspended Solids), and Total Toxic Organics (TTO).
Monitoring and Reporting Requirements:
- All composite samples must be flow-proportional.
- The facility’s total flow must not exceed 1,200,000 gallons per day.
- The pH of discharged wastewater must be maintained between 6.0 and 12.0 standard units.
- Discharge temperature cannot exceed 104 degrees Fahrenheit or 40 degrees Celsius.
- Dilution of discharge to meet treatment standards is strictly prohibited.
- A properly graded operator, as per SCDHEC, is required for all facilities with a pretreatment system.
Silfab Solar is responsible for collecting and analyzing samples for all listed parameters. Quarterly Self-Monitoring Reports (SMRs) must be submitted, postmarked by the 28th day following the completed reporting period. Annual calibration of flow measurement devices is also required, with reports submitted annually.
The permit includes provisions for immediate notification to the City of Rock Hill within 24 hours of any permit violation. Written reports on slug discharges, spills, upsets, malfunctions, or bypasses of pretreatment equipment that could impact the City’s wastewater system must be submitted within five working days. Bypasses of treatment facilities are generally prohibited in cases where effluent limitations would be exceeded.
Silfab Solar has been granted an interim period to implement necessary changes to comply with the final discharge limits, with full compliance expected by July 1, 2027. The company is also mandated to secure appropriate permits from the South Carolina Department of Health and Environmental Control (SCDHEC) for any modifications to its pretreatment system.
The permit can be modified, suspended, or revoked for various reasons, including permit violations, misrepresentation of facts, or falsifying reports. Non-compliance can lead to civil penalties of up to $2,000 per day and criminal penalties, including fines and imprisonment.
The public hearing for this permit will provide an opportunity for community members to learn more and provide input.
Silfab Solar Draft PERMIT 20252027
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