Sewage treatment site in San Diego exceeds capacity

Thirty million gallons of partially treated wastewater are being sent into ocean daily.

SAN DIEGO — Sewage from Tijuana has overwhelmed the international treatment plant in San Diego — which is now discharging 30 million gallons a day of partially treated wastewater into the Pacific Ocean.

Officials announced the situation Wednesday after five primary treatment tanks became clogged with sewage, garbage and sediment at the South Bay International Wastewater Treatment Plant just north of the U.S.-Mexico border.

“With the primary tanks out of commission that means we’re not skimming the solids off the top,” said Morgan Rogers, the San Diego area operations manager for the U.S. section of the International Boundary and Water Commission. “That means there’s going to be more solids when it leaves.”

Potential effects on ocean quality along South Bay shorelines are still being assessed.

“Whether it’s significant or not, I don’t know right now,” Rogers said. “Total suspended solids, turbidity, it’s going to go up.”

The tanks should be cleaned and repaired by early June, he said. However, the situation could repeat itself.

The international facility, which services Mexico, typically discharges about 25 million gallons of treated wastewater a day through the South Bay Ocean Outfall, which stretches about 3.5 miles off the coast of Imperial Beach.

However, since a major pipeline broke in Tijuana in August, the facility in San Diego has been forced to take an additional 5 million to 10 million gallons of sewage a day.

Officials said the pipe probably won’t be repaired until 2024, meaning the treatment plant may have to continue operating over its intended capacity.

“It was supposed to be fixed back in September, so we always knew something was up,” Rogers said of the broken pipeline. “I don’t want to say Mexico hasn’t been talking to us, but there hasn’t been a real clear plan.”

Beaches as far north as Coronado have been repeatedly closed this winter because of contamination. Real-time conditions are posted at sdbeachinfo.com.

Reports of sewage leaking over the border into the San Diego region stretch back at least to the 1930s. Significant improvements were made in the 1990s, but Tijuana’s wastewater facilities haven’t kept pace with the city’s population growth. Many poorer communities remain unconnected to the city’s sewer system.

Significant upgrades to wastewater facilities in Mexico are expected to kick off this year. More than $470 million has been slated for such work under a deal struck last year between the two nations.

Federal officials plan to double the capacity of the South Bay wastewater treatment plant by 2027.