The San Francisco Bay Regional Water Quality Control Board has issued Silicon Valley Clean Water (SVCW) a new and updated National Pollutant Discharge Elimination System (NPDES) permit effective April 1, 2018, through March 31, 2023.
NPDES permits establish discharge limits and conditions for discharges from municipal wastewater treatment facilities to waters of the United States. Under the new and previous NPDES permits, SVCW discharges treated water into lower San Francisco Bay just south of the San Mateo Bridge. The permit also establishes monitoring and reporting requirements.
The NPDES program is a federal program, under the Clean Water Act, that has been delegated to the State of California for implementation through the State Water Resources Control Board and the nine Regional Water Quality Control Boards.
An NPDES permit specifies an acceptable level of a pollutant or pollutant parameter in a discharge (for example, a certain level of bacteria). The permittee may choose which technologies to use to achieve that level. Some permits, however, do contain certain generic ‘best management practices’ (such as installing a screen over the pipe to keep debris out of the waterway). NPDES permits make sure that a state’s mandatory standards for clean water and the federal minimums are being met.
There are various methods used to monitor NPDES permit conditions. The permit requires the facility to sample its discharges and notify EPA and state regulatory agencies of the results. In addition, the permit requires the facility to notify EPA and state and local regulatory agencies when the facility determines it is not in compliance with the requirements of a permit. The permit also requires SVCW to send inspectors to certain regulated industries to ensure they are in compliance with the conditions imposed under their permits.
The term pollutant is defined very broadly in the Clean Water Act. It includes any type of industrial, municipal, and agricultural waste discharged into water. Some examples are dredged soil, solid waste, incinerator residue, sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand, cellar dirt and industrial, municipal, and agricultural waste.
SVCW’s wastewater treatment process consists of preliminary mechanical bar screens, primary sedimentation, secondary biological treatment through fixed film reactors and aeration basins, secondary clarification, mono- or dual-media filtration, chlorine disinfection using sodium hypochlorite, and dechlorination using sodium bisulfite.
SVCW’s treatment plant has an average daily treatment capacity of up to 29 million gallons per day (MGD) and a peak wet weather capacity of 71 MGD. From October 2012 through August 2017, the plant treated a daily average of 13.5 MGD and a maximum instantaneous flow of 70 MGD.
The order for SVCW’s permit can be viewed by clicking:
