Scientists at San Diego State University have developed a groundbreaking sewage-tracking system to monitor the levels of untreated sewage in the Tijuana River, which flows between the primary and secondary borders near Tijuana in San Diego. Led by biologist Trent Biggs and environmental engineer Natalie Mladenov, the team utilized specialized fluorescence sensors to detect and differentiate between treated and untreated sewage at key points along the river and in its estuary.
The Need for Real-Time Monitoring
The primary objective of the research team was to create a real-time sewage monitoring system to track the levels of pollutants in the Tijuana River. This system was vital in understanding the impact of untreated sewage on the environment and public health, especially as new infrastructure was being installed to address the ongoing issue of sewage leakage into the river. According to Biggs, one of the main challenges was determining the percentage of raw sewage with high bacteria levels in the river and understanding the fate of this sewage once it entered the water system.
The team initially focused their efforts on the San Diego River but quickly shifted their attention to the Tijuana River, where untreated sewage had been flowing unchecked into the Pacific Ocean for several years due to broken wastewater infrastructure. By utilizing fluorescence spectroscopy, which involves shining light waves through the water and analyzing the wavelengths that bounce back to the sensor, the scientists were able to accurately identify the presence of untreated sewage in the river. This method allowed them to determine that between 50-70% of the detritus in the river was untreated sewage during their data collection periods.
Advanced Technology for Sewage Detection
The use of fluorescence spectroscopy enabled the sensors to differentiate between organic compounds found in sewage and uncontaminated water based on the different wavelengths of light emitted by each. This technology provided real-time data transmission to the researchers, a significant improvement over existing sewage tracking systems that often required up to two weeks to alert water quality managers of contamination. Over a period of more than two years, the accuracy of the sensor readings was tested against manually collected samples analyzed in the lab, confirming the effectiveness of the system in monitoring sewage levels along the river.
During their research, the team observed fluctuations in sewage levels at different locations along the Tijuana River. For instance, at the estuary testing location, sewage levels decreased during high tides as river water flowed out into the ocean, but increased during low and moderate tides. In the main stem of the river, ocean tides had a lesser impact on sewage levels, but heavy rain events resulted in a significant drop in harmful pollutants, diluted by relatively cleaner runoff water. Biggs emphasized the importance of monitoring sewage levels during storm events, despite the challenges posed by high sediment loads and turbidity in the river.
Expanding Monitoring Capabilities
Looking ahead, the research team aims to expand the sewage-tracking system to include additional monitoring points along the river and into the ocean to provide real-time data on sewage and bacterial levels in San Diego County. Biggs highlighted the need for continued funding and partnerships with local organizations to enhance research capabilities and ensure the sustainability of the monitoring system. While SDSU has made significant progress in developing the technology, Biggs acknowledged the potential for further advancements in monitoring various compounds in different watersheds using fluorescence spectroscopy.
The International Boundary and Water Commission recently announced a project to expand the South Bay International Wastewater Treatment Plant, a key source of sewage leakage into the Tijuana River watershed. With over $400 million in federal funding secured for the project, the IBWC aims to address the environmental and public health hazards posed by untreated sewage in the region. Senator Alex Padilla commended the initiative as a step in the right direction towards mitigating the toxic waste flowing from the Tijuana River and emphasized the need for additional resources to tackle the crisis effectively.
In response to the escalating issue of sewage pollution in the Tijuana River Valley, the San Diego Congressional delegation secured funding for critical repairs to the South Bay International Wastewater Treatment Plant. The delegation’s efforts to expand the plant’s capacity and address harmful pollutants have been instrumental in combating the environmental impact of untreated sewage in the region. As government agencies and research institutions collaborate to improve sewage monitoring and treatment processes, the focus remains on safeguarding public health and the environment from the detrimental effects of sewage contamination.
Elected officials have called on the U.S. Centers for Disease Control and Prevention to investigate the health impacts of contaminants in the water, soil, and air resulting from sewage pollution in the Tijuana River. The CDC’s involvement signifies a growing recognition of the need to address public health concerns related to untreated sewage and its potential consequences on the community. By conducting a thorough investigation into the health risks associated with sewage contamination, the CDC aims to provide valuable insights for policymakers and stakeholders working to mitigate the impacts of sewage pollution on human health and the environment.
Reflecting on the progress made in developing the sewage-tracking system, Biggs expressed confidence in the system’s potential to be scaled up for monitoring larger rivers and bodies of water. The adaptability of fluorescence spectroscopy to detect over 150 different compounds offers a versatile solution for tracking various materials in different watersheds, enhancing the system’s applicability in diverse environmental settings. While challenges remain in expanding the monitoring network and securing adequate funding for research initiatives, Biggs remains optimistic about the future of sewage monitoring and treatment efforts in the Tijuana River watershed.
In conclusion, the innovative sewage-tracking system developed by SDSU scientists represents a significant advancement in monitoring and addressing untreated sewage in the Tijuana River. By leveraging state-of-the-art technology and scientific expertise, the research team has made substantial progress in understanding sewage contamination patterns and identifying opportunities for intervention. As research continues to evolve and partnerships strengthen, the potential for improved sewage monitoring and treatment in the region holds promise for a healthier environment and community. Through collaborative efforts and ongoing commitment to environmental stewardship, the fight against sewage pollution in the Tijuana River watershed is gaining momentum towards long-term solutions.
