Transboundary Flows and Permit Violations NPDES CA Order No. R November 5, 2015 International Boundary and Water Commission Agenda San Diego County, California South Bay International Wastewater Treatment Plant San Diego County, California 5 Pretreatment Headworks Allocation Draft Report Influent Violations None Effluent Violations - None Pretreatment First and Second Quarters Jan-June 2015 Influent Violations None Effluent Violations - None Pretreatment Third Quarter July September On evening of July 26, 2015 SBIWTP received influent causing over 100 NTU turbidity in effluent. Influent had odor of burnt oil, and became black overnight. The event caused a spike in effluent parameters. TSS = 143 mg/lCOD = 102 mg/l 9 Yogurt Canyon Smugglers Gulch Canyon Del Sol Silva Drain Stewarts Drain Goat Canyon Tijuana River SBIWTP Transboundary Flows 2015-Q1 & Q2 Transboundary Flows (Type A) Smugglers Gulch, Goat Canyon, Stewarts Drain, Canon del Sol, Silva Drain April 22- Overflow at Canon del Sol resulted in approximately 2,000 gallons of untreated sewage flowing into Tijuana River. 2015-Q1 & Q2 Transboundary Flows (Type A) BOD5 mg/L 54 Fecal Coliform number/100mL > TSS mg/L 42Total Coliform number/100mL > TDS mg/L 1330 Dissolved Oxygen mg/L 6.93 Turbidity NTU 24.3Pesticides g/L ND pH pH Units 6.84 Surfactants (MBAS) mg/L Total Nitrogen mg/L 43.2 Priority Pollutants g/L ND Total Phosphorus mg/L 5.25 Chronic Toxicity TUc 50 Enterococcus number/100mL > April 22- Overflow at Canon del Sol 2015 Q1 & Q2 Transboundary Flows (Type B) Tijuana River Overflows from CILA Pump Station (Jan Feb 2015) principally due to diversion screen clogging 2015-Q1 & Q2 Transboundary Flows (Type B) Tijuana River Overflows from CILA Pump Station June 17 Electrical failure caused partial pump shutdown of Pump Station CILA, causing 47,600 gallons to flow into the U.S. April 22- Drain of potable water to river for tank repair caused 285,307 gallons to flow into the U.S. 2015-Q3 Transboundary Flows (Type B) Tijuana River Overflows from CILA Pump Station July Flow of 556,000 gallons in Yogurt Canyon. CEPST and IBWC responded with Vac trucks and pumped approximately 50,000 gallons returned to Goat Canyon Diversion (hence to SBIWTP) 2015-Q3 Transboundary Flows (Type B) Tijuana River Overflows from CILA Pump Station August 1, 2, 3, 6, 8- small overflows, principally at night and weekends due to screen clogging. 2015-Q3 Transboundary Flows (Type B) Tijuana River Overflows from CILA Pump Station Flows on 9/19/15 - CILA Pump Station in Mexico initiated resume operations procedures on 9/19/2015 at approximately 1400 following a period of wet weather flow beginning 9/15/15. Only partial pumping capacity was able to resume due to breakdown of one pump at Pump Station CILA and one pump at Pump Station 1A on 9/19/2015 at Pumps were not able to be repaired until 1100 on 9/21/15. 2015-Q3 Transboundary Flows (Type B) Tijuana River Overflows from CILA Pump Station 2015-Q4 Transboundary Flows -Type B Tijuana River Overflows from CILA Pump Station Oct-Dec 2015 2015-Q4 Transboundary Flows -Type B Tijuana River Overflows from CILA Pump Station Oct-Dec 2015 Oct 13 loss of partial pumping capacity due to motor control failure of one pump and rag fouling of second pump Oct 14- motor control failure of one pump Oct 17- pump failure Historical Transboundary Flows Rio Tijuana Dry Weather Transboundary Flows Rio Tijuana Wet Weather Transboundary Flows -2009 Rio Tijuana Wet Weather Transboundary Flows-2011 Rio Tijuana Wet Weather Transboundary Flows-2013 Rio Tijuana Wet Weather Transboundary Flows Ratio: Flow Days/Days with Precip Rio Tijuana Rio Tijuana Transboundary Flow Analysis Observations 1.PB CILA successfully controls dry weather flows for 70% of year 2.Flow days abnormally high in 2009, 2011 and Flows < 1000 lps make up 45% of flow days (removing 100 lps or less). Control of these would reduce flow days by 50 4.If flows up to 1500 lps were diverted, could reduce another 20 flow days (problems with sediment, O&M) Rio Tijuana Transboundary Flow Analysis Suggestions 1.Engineering study to improve O&M of existing infrastructure 2.Modify existing meter at PB CILA to enable flow data to be accessed 3.Develop Joint Engineers Report for Operation of the CILA Pump Station 4.Improve measurement/reporting at IBWC gage 5.Install flow meter in Rio Tijuana above CILA PS diversion Questions