RWQCB renews Camp Pendleton discharge permit

The San Diego Regional Water Quality Control Board renewed Camp Pendleton’s discharge permit for the Southern Regional Tertiary Treatment Plant and the Advanced Water Treatment Plant.

The RWQCB’s Nov. 13 approval updates National Pollutant Discharge Elimination System (NPDES) requirements for the facilities which use the Oceanside Outfall to discharge effluent into the Pacific Ocean.

The Southern Regional Tertiary Treatment Plant (SRTTP) treats wastewater from the southern portion of the base. The Advanced Water Treatment Plant in the Haybarn Canyon area processes to potable standards water pumped from groundwater wells within the Ysidora hydrologic area.

The previous NPDES permit for the SRTTP was issued in November 2008. The permit was modified in June 2012 to recognize the existence of the Haybarn Canyon plant which began full continuous discharge on March 4, 2013, to acknowledge the expansion of the SRTTP average daily design capacity from 5.0 million gallons per day (mgd) to 7.5 mgd with daily peaks at 10 mgd, and to add technology-based effluent limitations and monitoring requirements. The modifications did not change the base’s discharge limit of 3.6 mgd.

The renewed permit expands the receiving water zone where bacterial limitations apply. The previous permit applied limitations to a zone bounded by the shoreline and a distance of 1,000 feet from the shoreline or the 30-foot depth contour. The new permit expands the zone to include ocean waters used for water contact sports, or three nautical miles into the Pacific Ocean from the shoreline.

The Oceanside Outfall is used by the Fallbrook Public Utility District, the City of Oceanside, and Genentech as well as by Camp Pendleton. The City of Oceanside’s evaluation of the receiving waters indicates that effluent from Camp Pendleton and FPUD contribute relatively low densities of bacteria compared to the city’s effluent.

The City of Oceanside and RWQCB staff are working together to achieve full compliance with the bacterial limitations under separate waste discharge requirements, and the RWQCB will work with all dischargers if new or modified facilities or processes are implemented.

The renewed permit also changes the requirement for repeat effluent sampling for chronic toxicity in the event of chronic toxicity exceedance. The previous order required an increase in the sampling to a minimum of two times per months until at least two consecutive toxicity tests showed no violations.

The new regulations require six additional tests over a 12-week period. In the event a single sample exceeds any of the single sample bacterial limitations, the permit which had not previously required additional monitoring now requires repeat sampling to determine the extent and persistence of the exceedance.

The monitoring frequency for oil and grease in the influent and effluent was reduced from weekly to monthly; the SRTTP effluent has been meeting the limitations for oil and grease and the monthly monitoring requirement is consistent with that for other wastewater treatment plants.

Effluent monitoring for arsenic, cadmium, chromium, lead, mercury, nickel, selenium, zinc, cyanide, non-chlorinated and chlorinated phenolic compounds, endosulfan, and radioactivity has been reduced from quarterly to semi-annually. Effluent monitoring for copper, endrin, aldrin, beryllium, dieldrin, hepatchlor, heptachlor epoxide, hexachlorobenzene, polynuclear aromatic hydrocarbons, polychlorinated biphenyls, tetrachlorodibenzodioxin equivalents, and toxaphene has been increased from semi-annually to quarterly.

Between the issuance of the 2008 permit and Oct. 17, 2013, Camp Pendleton’s self-monitoring reports indicated eight effluent violations, 29 deficient monitoring violations, and seven unauthorized discharges.