MILLSTONE POWER STATION, Waterford, CT: NPDES CT0003263 discharge permit, effluent exceedances, inspections, penalties

MILLSTONE POWER STATION, Waterford, Connecticut: Individual permit CT0003263; Administratively continued; issued December 14, 1992, term to December 13, 1997, by CT DEP; discharges to LONG ISLAND SOUND.

22 of the 49 pollutants listed for NPDES CT0003263 have no violation or effluent exceedance.

• Flow, in conduit or thru treatment plant: 10 limits, 48 violations of any kind, 48 effluent exceedances, latest October 31, 1999, largest 5,614% over the limit.
• Solids, total suspended: 31 limits, 29 violations of any kind, 23 effluent exceedances, latest October 31, 2024, largest 832% over the limit.
• Chlorine, free available: 12 limits, 14 violations of any kind, 14 effluent exceedances, latest September 30, 2010, largest 17,180% over the limit.
• Flow, gallons/batch: 19 limits, 14 violations of any kind, 12 effluent exceedances, latest August 31, 2010, largest 136% over the limit.
• Chlorine, total residual: 3 limits, 12 violations of any kind, 12 effluent exceedances, latest October 31, 2010, largest 2,900% over the limit.
• pH: 27 limits, 18 violations of any kind, 10 effluent exceedances, latest November 30, 2014.
• Temp. diff. between samp. & upstrm deg. F: 12 limits, 11 violations of any kind, 6 effluent exceedances, latest November 30, 1999, largest 110% over the limit.
• Boric acid: 11 limits, 9 violations of any kind, 6 effluent exceedances, latest June 30, 2000, largest 700% over the limit.
• Zinc, total [as Zn]: 11 limits, 4 violations of any kind, 4 effluent exceedances, latest June 30, 1997, largest 171% over the limit.
• Oil & Grease: 20 limits, 8 violations of any kind, 3 effluent exceedances, latest April 30, 2005, largest 71,900% over the limit.
• Temperature, water deg. fahrenheit: 26 limits, 5 violations of any kind, 2 effluent exceedances, latest July 31, 2010, largest 20% over the limit.
• Copper, total [as Cu]: 11 limits, 2 violations of any kind, 2 effluent exceedances, latest June 30, 1997, largest 14% over the limit.
• pH, maximum: 0 limits, 2 violations of any kind, 2 effluent exceedances, latest March 31, 2016.
• Hydrazine: 10 limits, 9 violations of any kind, 1 effluent exceedance, latest March 31, 1997, largest 23% over the limit.
• Boron, total: 0 limits, 8 violations of any kind.
• Nitrogen, ammonia total [as N]: 6 limits, 7 violations of any kind.
• Ethanolamine: 0 limits, 3 violations of any kind.
• Flow rate: 8 limits, 2 violations of any kind.
• Nitrogen, Kjeldahl, total [as N]: 0 limits, 2 violations of any kind.
• Dichlorodifluoromethane: 0 limits, 2 violations of any kind.
• Chlorodifluoromethane: 0 limits, 2 violations of any kind.
• Flow, maximum during 24 hr period: 0 limits, 2 violations of any kind.
• Surfactants, anionic: 0 limits, 2 violations of any kind.
• Turbidity: 0 limits, 1 violation of any kind.
• Molybdenum, total [as Mo]: 0 limits, 1 violation of any kind.
• LC50 Static 48Hr Acute Americamysis bahia (formerly Mysidopsis bahia): 0 limits, 1 violation of any kind.
• LC50 Static 48Hr Acute Cyprinodon variegatus: 0 limits, 1 violation of any kind.
• Lead, total [as Pb]: 11 limits.
• Nickel, total [as Ni]: 11 limits.
• Thermal Discharge: 8 limits.
• Pass/Fail Static 48Hr Acute Americamysis bahia (formerly Mysidopsis bahia): 8 limits.
• Pass/Fail Static 4 Day Chronic Mysidopsis Bahia: 8 limits.
• Surfactants [MBAS]: 6 limits.
• Pass/Fail Static 96 Hr Acute Cyprinodon Variega: 6 limits.
• Pass/Fail Static 4 Day Chronic Cyprinodon Variega: 6 limits.
• Iron, total [as Fe]: 5 limits.
• BOD, 5-day, 20 deg. C: 3 limits.
• Oxygen demand, chem. [low level] [COD]: 3 limits.
• Cadmium, total [as Cd]: 3 limits.
• Chromium, total [as Cr]: 3 limits.
• Specific conductance: 2 limits.
• Hydrogen peroxide: 2 limits.
• Freon, total: 2 limits.
• Formic acid: 2 limits.
• Oxalic acid: 2 limits.
• Citric acid: 2 limits.
• EDTA: 2 limits.
• Beryllium, total recoverable [as Be]: 1 limit.
• Lithium, total [as Li]: 1 limit.

• July 24, 2024: Monitoring Violations - Invalid/Unrepresentative Sample (ST6).
• July 24, 2024: Permit Violations - Violation Specified in Comment (ST6).
• April 14, 2022: Monitoring Violations - Invalid/Unrepresentative Sample (ST6).
• April 14, 2022: Monitoring Violations - Improper Analysis or Lab Error (ST6).

MILLSTONE POWER STATION among its neighbors

3 discharge permits are in the Niantic River subwatershed (HUC 011000030304); CT0003263 is one. Its county: 64, 12 major; CT0003263 is major permit.

Other permits in the Niantic River subwatershed (HUC 011000030304)

• 317 ROPE FERRY ROAD, Waterford: CTGSN2931, minor, term to 2020-09-30
• ACES HIGH RV PARK, East Lyme: CTSSD0031, minor, term to 2031-10-12