6.3 VPDES Permit Compliance, DMRs & Overflow Reporting

VPDES Permit Compliance, DMRs & Overflow Reporting

The ABC Wastewater outline places 15 items in Security, Safety, and Administrative Procedures, including "complete required regulatory reports," "ensure compliance with all applicable regulations," and "complete operation and maintenance reports." In Virginia, all of that flows through the Virginia Pollutant Discharge Elimination System (VPDES) permit administered by DEQ under 9VAC25-31, the state's delegated NPDES program.

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1. How a Permit Limit Is Set

Every effluent limit in a VPDES permit comes from one of two derivations, and the more stringent one controls.

Technology-based effluent limits (TBELs)

Derived from what treatment technology can achieve, regardless of the receiving stream. For publicly owned treatment works these are the secondary treatment standards (40 CFR Part 133):

Equivalent-to-secondary standards (45 mg/L monthly, 65 mg/L weekly, 65 percent removal) may apply to trickling filter and stabilization pond facilities that qualify.

Water-quality-based effluent limits (WQBELs)

Derived backward from the water quality standard in the receiving stream, using the stream's design low flow (commonly the 7Q10 - the lowest 7-day average flow with a 10-year recurrence interval), the background concentration, and a mixing zone analysis if one is allowed. WQBELs are what produce ammonia limits, total residual chlorine limits, metals limits, and the nutrient limits in the Chesapeake Bay watershed.

Where a WQBEL is more stringent than the TBEL - which is common for ammonia, chlorine, and nutrients - the WQBEL governs. Anti-backsliding rules generally prohibit a renewed permit from being less stringent than the prior one, and antidegradation policy limits new or increased loadings to high-quality waters.

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2. Reading the Limit Types

A permit page contains several distinct statistical limits, and confusing them produces false compliance and false violations alike.

The mass-limit trap. A plant meeting 25 mg/L BOD against a 30 mg/L limit is concentration-compliant, but if the permit also carries a mass limit calculated at design flow and the plant is running well above design flow, the mass number can violate while the concentration number looks fine. Always compute both.

Sampling type matters as much as the number

• Grab sample - a single sample at a single moment. Required for pH, dissolved oxygen, temperature, total residual chlorine, oil and grease, and bacteria - anything that changes on standing.
• Composite sample - multiple aliquots combined, either time-proportional (equal volume at equal time intervals) or flow-proportional (volume proportional to flow). Required for BOD, TSS, nutrients, and metals. Flow-proportional composites are the more accurate representation of mass load where flow varies.
• The permit specifies sample type, frequency, and location. Substituting a grab where a composite is required is a monitoring violation even if the result is good.

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3. The Discharge Monitoring Report

The DMR is the legal record of compliance. In Virginia it is submitted electronically through eDMR under the federal NPDES Electronic Reporting Rule.

Preparing a DMR

1. Transcribe from the laboratory report and the flow record, not from memory or from a working spreadsheet that has been edited.
2. Apply the permit's calculation rules for averages, including how to handle non-detects (typically reported at the quantification level with a qualifier, per the permit).
3. Report every required parameter for every required period. A blank cell is a monitoring violation.
4. Report violations on the DMR itself, with an explanation - the DMR is a self-reporting instrument, and a violation the utility reports is treated very differently from one DEQ finds.
5. Attach or retain supporting records: bench sheets, chain of custody, instrument calibration logs, and flow charts.

Signatory and certification

DMRs must be signed by a principal executive officer or ranking elected official for a municipality, or by a duly authorized representative whose authorization has been submitted to DEQ in writing. The signature is placed beneath a certification stating that the information was prepared under the signer's direction, that qualified personnel gathered and evaluated it, and that the signer is aware there are significant penalties for submitting false information, including the possibility of fine and imprisonment.

That certification is why data integrity is not a paperwork matter. Falsifying a DMR is a federal crime, and for a Virginia licensee it is simultaneously a prohibited act under 18VAC160-30-320 exposing the individual license to revocation.

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4. Reporting Noncompliance

9VAC25-31-190 sets the timelines that every wastewater operator must know.

Sanitary sewer overflows are unpermitted discharges and are reported under the same 24-hour oral and 5-day written framework, with additional local and, where the overflow reaches state waters or threatens a water supply, VDH and local emergency management notification. The written report should record location, receiving water, start and stop times, estimated volume and the method used to estimate it, cause, corrective action, and cleanup and public notification performed.

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5. Bypass and Upset - Narrow Defenses

Both are defined terms with strict conditions. Neither is a general excuse.

Bypass (9VAC25-31-200 U)

A bypass is the intentional diversion of waste streams from any portion of a treatment facility.

Bypass is prohibited unless:

1. It was unavoidable to prevent loss of life, personal injury, or severe property damage;
2. There was no feasible alternative - and specifically, the absence of auxiliary treatment or of adequate back-up equipment that should have been installed during reasonable engineering design is not an acceptable justification if the bypass could have been prevented by exercising reasonable engineering judgment; and
3. The permittee submitted the required notices (10 days advance for anticipated; 24-hour oral and 5-day written for unanticipated).

A bypass that does not cause effluent limits to be exceeded is allowed only if it is for essential maintenance to assure efficient operation.

Upset (9VAC25-31-200 T)

An upset is an exceptional incident in which there is unintentional and temporary noncompliance with technology-based limits because of factors beyond the reasonable control of the permittee.

Upset is an affirmative defense - the permittee bears the burden of proof through properly signed contemporaneous operating logs or other relevant evidence showing:

1. An upset occurred and the permittee can identify the specific cause;
2. The facility was at the time being properly operated;
3. The permittee submitted the 24-hour notice; and
4. The permittee took all reasonable steps to minimize or correct the noncompliance.

Expressly excluded from the upset defense: noncompliance caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation.

Read those exclusions carefully - they describe most of the reasons plants actually violate. The upset defense is available for a toxic industrial slug the plant could not have known about, not for a blower that failed because it was never serviced.

The operational takeaway: the defense lives or dies on contemporaneous records. Logs written at the time, showing normal operation before the event, the moment of detection, the actions taken, and the notifications made, are the evidence. Records reconstructed afterward are not.

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6. Other Permit Obligations Operators Carry

• Proper operation and maintenance - the permit contains a standing condition requiring the permittee to at all times properly operate and maintain all facilities and systems of treatment and control, including adequate laboratory controls, appropriate quality assurance, and adequate staffing and training.
• Duty to mitigate - take all reasonable steps to minimize or prevent any discharge in violation of the permit that has a reasonable likelihood of adversely affecting human health or the environment.
• Duty to halt or reduce activity is not a defense - it is not a defense to claim that it would have been necessary to halt or reduce the permitted activity to maintain compliance.
• Records retention - monitoring records, calibration and maintenance records, original strip chart recordings, and copies of reports must be kept for at least 3 years, extended at DEQ's request and automatically for the duration of any unresolved litigation.
• Right of entry - DEQ may enter, inspect, sample, and copy records at reasonable times.
• Operator requirement - the treatment works must be operated by an operator holding a valid license of the appropriate class, which routes back to 18VAC160-30 and to Table 1 of 9VAC25-790-290.