Public Notice
Significant Non-Compliance for 2021


Notice is hereby given that pursuant to the federal regulations contained in 40 CFR 403.8.f(2)(vii), Central Contra Costa Sanitary District (Central San) is required to publish the names of all Industrial Users (IUs) of Central San’s public sewer system that were determined to be in Significant Non-Compliance (SNC) with applicable pretreatment standards or other pretreatment requirements during the 2021 calendar year. Federal regulations establish objective criteria for Central San to use to determine if an IU is in SNC.


The following IU was found to have discharged process wastewater in violation of Central San’s Local Discharge Limits in a manner that met the definition of SNC.

Industrial User - Diablo Valley College, 321 Golf Club Road, Pleasant Hill, CA 94523

Nature of Violation - Limit violations for mercury (4) in the discharge from the Physical Science Building at concentrations that met the SNC criteria [Technical Review Criteria (TRC) and chronic].

Follow-up Action Taken - Central San issued Notices of Violation (NOVs) for the violations. The IU investigated potential sources of mercury within the laboratory operations and did not locate any significant mercury sources. The IU cleaned the pretreatment unit serving the Physical Science Building to improve the unit’s ability to remove regulated pollutants. Violations occurred after this cleaning, so the IU conducted another cleaning of the pretreatment unit and flushed the waste lines from the laboratory areas to the pretreatment unit to remove potential legacy sources of mercury. Resampling demonstrated that the IU returned to compliance after the violations were recorded. Central San initiated a formal enforcement action with this IU based on the pattern of non-compliance. The formal enforcement action was resolved in November 2021.

Reporting Violations - No IUs were in SNC for reporting violations in 2021.