Wastewater from Tijuana has overwhelmed the international treatment plant in San Diego, which now discharges 30 million gallons per day of partially treated wastewater into the Pacific Ocean.
Authorities announced the situation Wednesday after five primary treatment tanks clogged with sewage, trash and sludge at the South Bay International Wastewater Treatment Plant, just north of the US-Mexico border.
“With the primary tanks out of service, that means we’re not removing the solids off the top,” said Morgan Rogers, San Diego-area operations manager for the US section of the International Boundary and Water Commission. “That means there will be more solids when he leaves.”
Potential effects on ocean quality along the South Bay shorelines are still being evaluated.
“Whether it’s significant or not, I don’t know at this point,” Rogers said. “Total suspended solids, turbidity, it’s going to go up.”
The tanks should be cleaned and repaired in early June, he said. However, the situation could repeat itself.
The international facility, which serves Mexico, typically discharges about 25 million gallons of treated wastewater per day through the South Bay Ocean Outfall, which runs about 3.5 miles off the coast of Imperial Beach.
However, since a major pipeline ruptured in Tijuana in August, the San Diego facility has been forced to take an additional 5 million to 10 million gallons of wastewater per day.
Officials said the pipeline likely won’t be repaired until 2024, meaning the treatment plant may need to continue operating above its planned capacity.
“It was supposed to be fixed in September, so we always knew something was up,” Rogers said of the broken pipe. “I don’t want to say that Mexico hasn’t been talking to us, but there hasn’t been a really clear plan.”
Beaches as far north as Coronado have been closed repeatedly this winter due to sewage contamination. Real-time conditions are posted on sdbeachinfo.com.
Reports of sewage leaks across the border into the San Diego region date back at least to the 1930s. Significant improvements were made in the 1990s, but Tijuana’s sewage facilities have not followed suit. rate of population growth in the city. Many poorer communities remain disconnected from the city’s sewer system.
Significant updates to the wastewater facilities in Mexico are expected to start this year. More than $470 million it has been scheduled for such work under an agreement reached last year between Mexico and the United States.
Federal officials plan to double the capacity of the South Bay International Wastewater Treatment Plant by 2027.
