Drinking Water Projects: San Gabriel Valley, California

Decades of historical industrial development can leave a lasting legacy of groundwater contamination, threatening vital regional drinking water supplies. In California's San Gabriel Valley, an extensive underground contaminant plume impactfully compromises an aquifer providing drinking water to more than one million residents. While standard technologies like air stripping and carbon adsorption successfully extract basic volatile organic compounds, emerging complex chemical micropollutants require a more advanced solution.

Two particularly stubborn contaminants are N-nitrosodimethylamine (NDMA), a highly carcinogenic byproduct of rocket fuel manufacturing and chemical water treatment, and 1,4-dioxane, a highly mobile stabilizer found in industrial solvent plumes. To address these threats, treatment facilities leverage specialized ultraviolet light and UV-oxidation systems. While ultraviolet light alone cost-effectively breaks down NDMA, combining high-intensity UV lamps with hydrogen peroxide creates powerful oxidization reactions that permanently destroy resilient 1,4-dioxane molecules.

By modernizing older, high-energy treatment designs with optimized UV-oxidation infrastructure, regional water utilities across five distinct local plants now safely treat over 50 million gallons per day. These advanced systems drastically lower operating overhead—slashing municipal electricity consumption by more than 80 percent—while simultaneously driving NDMA levels below 2 parts per trillion and 1,4-dioxane below 0.5 parts per billion.

Read this comprehensive case study to analyze specific influent data and learn how advanced oxidation reliably restores contaminated groundwater basins.