OTTAWA WASTEWATER TREATMENT PLANT
NPDES ID: OH0026921
E — SNC: Effluent violation (monthly average limit)
The facility discharged more of a pollutant than its permit allows, based on a monthly average.
This quarter: 1 effluent violation.
Violations
April 30, 2026
Oxygen, dissolved [DO]
80% over limit
Discharged 1.07 mg/L against a permitted limit of 5.4 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
February 28, 2026
Mercury, total low level
23% over limit
Discharged 0.00000555 mg/L against a permitted limit of 0.0000045 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2025
Mercury, total low level
716% over limit
Discharged 0.0000367 mg/L against a permitted limit of 0.0000045 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Mercury, total low level
79% over limit
Discharged 0.000125 kg/d against a permitted limit of 0.00007 kg/d (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2025
Mercury, total low level
113% over limit
Discharged 0.0000096 mg/L against a permitted limit of 0.0000045 mg/L (MO AVG)
DMR, Limited - Numeric Violation
June 30, 2025
Toxicity [chronic], Ceriodaphnia dubia
21% over limit
Discharged 1.7 toxic against a permitted limit of 1.4 toxic (MO AVG)
DMR, Limited - Numeric Violation
August 31, 2024
Toxicity [acute], Ceriodaphnia dubia
0% over limit
Discharged 0 toxic against a permitted limit of 1 toxic (DAILY MX)
DMR, Limited - Overdue
Toxicity [chronic], Ceriodaphnia dubia
0% over limit
Discharged 0 toxic against a permitted limit of 1.42 toxic (MO AVG)
DMR, Limited - Overdue
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)