MAYFIELD STP
NPDES ID: KY0021211
S — SNC: Compliance schedule violation
The facility missed a deadline in its compliance schedule by more than 90 days.
This quarter: 5 effluent violations, 1 reporting violation.
Violations
June 30, 2026
Copper, total recoverable
157% over limit
Discharged 0.036 mg/L against a permitted limit of 0.01399 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
157% over limit
Discharged 0.036 mg/L against a permitted limit of 0.01399 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
May 31, 2026
Nitrogen, ammonia total [as N]
72% over limit
Discharged 5.15 mg/L against a permitted limit of 3 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
68% over limit
Discharged 59.4739995 kg/d against a permitted limit of 35.4119997 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
94% over limit
Discharged 3.88 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2026
Copper, total recoverable
150% over limit
Discharged 0.035 mg/L against a permitted limit of 0.01399 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
150% over limit
Discharged 0.035 mg/L against a permitted limit of 0.01399 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Toxicity, Acute
0% over limit
Discharged 0 toxic against a permitted limit of 1 toxic (DAILY MX)
DMR, Limited - Overdue
August 31, 2025
Nitrogen, ammonia total [as N]
23% over limit
Discharged 29.05599976 kg/d against a permitted limit of 23.6079998 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
29% over limit
Discharged 2.58 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
120% over limit
Discharged 6.59 mg/L against a permitted limit of 3 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
July 31, 2025
Nitrogen, ammonia total [as N]
500% over limit
Discharged 18 mg/L against a permitted limit of 3 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
509% over limit
Discharged 12.17 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
June 30, 2025
Toxicity, final conc toxicity units
0% over limit
Discharged 0 toxic against a permitted limit of 1 toxic (MAXIMUM)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
284% over limit
Discharged 7.68 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
323% over limit
Discharged 12.7 mg/L against a permitted limit of 3 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
May 31, 2025
Nitrogen, ammonia total [as N]
101% over limit
Discharged 4.02 mg/L against a permitted limit of 2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
99% over limit
Discharged 5.96 mg/L against a permitted limit of 3 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
March 31, 2025
Nitrogen, ammonia total [as N]
91% over limit
Discharged 14.3 mg/L against a permitted limit of 7.5 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
February 28, 2025
Nitrogen, ammonia total [as N]
37% over limit
Discharged 10.3 mg/L against a permitted limit of 7.5 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (4 months ago)
Last confirmed
August 15, 2026 (6 hours ago)