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Accident # | 132209 |
tate Police # | N/A |
Accident Date | 2011-07-03 |
Report Date | 2011-07-11 |
Follow-up Date | 0000-00-00 |
Follow-up: | No |
Pollutant | Duration | Point Source | Greenhouse Gas | Criteria Pollutant | Ozone forming chemical | Amount of Release |
Wastewater | 20 days and counting | Outfall 001 | NO | NO | NO | 130,000,000.0 gallons |
Accident Classified As: Reportable Quantity
Wastewater treatment facilities suffered a loss of biological degradation capability at its Advanced Wastewater Treatment Plant, which was expected to result in LPDES exceedances through Outfall 001 (treated wastewater). Outfall 001 was discharging treated process wastewater into the Mississippi River. The letter from the refinery dated 7/11/11 states that the root cause of the upset condition was still being investigated, but the letter states a belief that inhibition of biomass began mid-June and was exacerbated by cooling system issues in late June. Effluent permit limits were exceeded on three different days - June 29, July 1 , July 4 - for elevated BOD count above the permitted 4,765 lbs BOD/day as indicated by sampling results. On June 29 the plant released 5,408 lbs of BOD/day. On July 1, they released 5,501 lbs BOD/day. On July 4, they released 12,820 lbs BOD/day.
The loss of degradation capability was an exceptional incident in which there was an unintentional and temporary noncompliance with technology based permit effluent limitations because of factors beyond the reasonable control of the ExxonMobil. We are continuing to investigate the root cause of the upset condition.
At the time of the letter dated 7/11/11, the discharge was still occurring, and mitigation and recovery steps implemented included increased storage of influent wastewater, addition of biomass to AWT, restored cooling tower capability to lower wastewater temperature to optimum, and initiation of significant wastewater load reduction measures.
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