Mexico is diverting untreated wastewater into the Tijuana River as it works to repair its faulty sewage infrastructure.
About five million gallons per day (MGD) have been diverted since April 8 as Mexico repairs a critical junction box that is a part of its International Collector project. The junction box must be dried so it can be rebuilt with reinforced concrete.
On Wednesday, Mexico shut off the water supply to a portion of Tijuana for other projects, which eliminated the need to divert wastewater into the Tijuana River.
Because of that, the average daily impact has been three million gallons per day, according to Maria-Elena Giner, commissioner for the U.S. section of the International Boundary and Water Commission.
To help remove as much wastewater as possible from the river, Mexico is working to activate its PBCILA lift station, which is usually turned off during the dry season. It is expected to be operational by Sunday. In the meantime, Mexico borrowed a front-end loader from the US to remove sediment near the PBCILA station and expedite the work.
The International Collector is a pipeline that carries raw sewage from Tijuana to treatment plants, and it is aging and prone to leaks. Mexico is relining the existing pipeline and will connect a bypass line in the interim.
In early March, Mexico discovered two unknown lines sending excess flow into the International Collector. The first was quickly found and resolved, but the second has not yet been identified. Mexico has been using sandbags, steel plates, and pumps in effort to divert it.
Phase 1 of the project – installing the new pipeline – is expected to be complete by April 17, Giner said in a statement. Shortly after, Phase 2 will begin, in which Mexico will rehabilitate its old International Collector.
During that time, it’s anticipated that the collector will not send wastewater to the South Bay International Wastewater Treatment Plant (SBIWTP) in San Diego for six days. The IBWC and its operator, Veolia North America, are making plans to mitigate the impact the pause will create.
Right now, the IBWC and Mexico are discussing a potential April 21 start date for Phase 2.
Mexico initially proposed that the International Collector project be completed in just one phase, which would have sent 25-30 MGD of wastewater into the Tijuana River for three to four weeks.
However, the IBWC, the U.S. Enivornmental Agency (EPA), and the U.S. Department of State urged Mexico to implement a bypass solution, and Mexico agreed. Doing it this way is expected to prevent more than half a billion gallons of wastewater from reaching the river.
“Although this is bad news, it’s not as bad as the 25 MGD that could have wound up in the river under other alternatives that had been considered,” Giner said.
Mexico is now finalizing its long anticipated San Antonio de los Buenos Wastewater Treatment Plant (SAB), which is expected to make a significant dent in the ongoing Tijuana sewage crisis.
Giner said it is expected to be in compliance with Mexican standards in two to three weeks, and will treat 18 MGD.
During Phase 2 of the International Collector project, the PBCILA station will be turned off, and flow from the International Collector will be sent to the SAB plant. The PBCILA will be turned on again once Phase 2 is complete.
The International Collector is the largest wastewater conveyance pipe in Tijuana, and it has been plagued by leaks. Once complete, it will have the capacity to carry up to 60 million gallons per day of untreated sewage to treatment plants in the US and Mexico. San Diego’s own treatment plant is currently being expanded.
As a concrete contractor, I understand the critical role infrastructure plays in public health and environmental protection. The ongoing sewage discharge into the Tijuana River during essential repairs highlights the urgent need for durable, well-planned construction solutions. It’s imperative that we prioritize long-term resilience in our projects to prevent such environmental impacts. Thank you for bringing attention to this pressing issue.
And of course millions of hard-working U.S. taxpayers dollars are paying for this so called upgrade of the sewer system, and of course, they will run into problems that will require more money from us, and then “we just don’t have the money to maintain our mexican sewage plant”, which will require more money from us, can you imagine the who will be on the mexican payroll when it’s done (which it will never be done), every so called engineer in Tijuana will be on the payroll, we are idiots.