BOD Excursion With a Late Call

Compliance status. The January monthly average of 410 mg/L (405 mg/L on re-run) exceeds the 250 mg/L monthly average limit regardless of cause. The daily maximum of 300 mg/L may also be exceeded depending on daily values, but the monthly average alone is enough for a violation. The upset defense is narrow: it generally requires that the facility was properly operated and maintained, that the upset was not caused by negligence, and that required notifications were made. Late notification (72 hours against 24) and late written report (day 8 against 5 days) are separate compliance failures. The annual certified report filed after 1 February is another missed deadline.\n\nAudit conclusion. The manager's argument misstates the legal effect of an upset. The exceedance remains a permit violation; the upset may affect enforcement response, not the existence of noncompliance. The auditor should document each violation with the monitoring data, lab re-run, notification log, and report submission records, and avoid legal conclusions beyond the evidence.\n\nJudgement point: whether the upset was truly involuntary requires evidence of operation and maintenance, not just the manager's statement.

Root cause analysis. The new product line likely changed organic loading; the failed aerator reduced treatment capacity. I would examine whether the change was reviewed for environmental aspects and permit capacity before startup, whether the aerator had a preventive maintenance schedule, and whether the upset response plan was followed.\n\nEvidence to request: production change records, wastewater strength data before and after the new line, maintenance work orders, aeration equipment logs, operator staffing, and the pretreatment system design basis. Corrective actions should address load forecasting, pretreatment capacity, maintenance criticality, and alarm response.\n\nTesting effectiveness: sample daily BOD/COD data for the next quarter, verify the aerator repair and redundancy, review the revised upset procedure and training, and confirm that the compliance calendar is controlled. A single report correction is not enough; the system should prevent recurrence and detect excursions early.\n\nLink to audit scope: the January–March period should be tested for repeat excursions. If February and March show normal results, that supports correction but not necessarily effective corrective action until the root cause is addressed.

Finding statements. (1) The January monthly average BOD of 410 mg/L exceeded the permit limit of 250 mg/L. (2) The required oral notification was made at 72 hours instead of within 24 hours, and the written report was submitted on day 8 instead of within five days. (3) The annual certified compliance report was not submitted by 1 February. Each should be stated factually with evidence references and the applicable permit or regulatory requirement.\n\nHandling the missed report. This is a separate compliance finding, not a minor administrative issue. The follow-up should require a submitted report, a documented reason for the delay, and a control to prevent recurrence, such as a compliance calendar with named owners and escalation. The auditor should verify submission and review the next reporting cycle.\n\nJudgement point: do not merge all three issues into one finding. Separate findings allow the client to correct each requirement and allow the auditor to verify closure individually.