Ozone Disinfection and Treatment of Urban Storm Drain Dry-Weather Flows: A PilotTreatment Plant Demonstration Project on the Kenter Canyon Storm Drain System in Santa Monica

摘要

The Pico-Kenter Canyon storm drain is typical of many in the region. Chemicalcontamination is low, but the water contains pathogenic human bacteria and viruses, signifying a health threat. Ozone is used to disinfect drinking water while forming few chlorination by-products. Santa Monica City evaluated ozonation of dry-weather storm drain flows to disinfect the water and estimated chemical concentrations. At ozone doses of 10-20 mg/L, microbial populations were reduced 3-5 log (99.9% to 99.999%). In many effluent samples, the reduction qualified the water for landscape irrigation projects. While ozonation by-products (aldehydes) were detected in the effluent (<100PPB), no increase in halogenated by-products, or mutagenicity, was observed. Based on State Ocean Objectives and Federal Potable Water MCLs, the primary hazardous chemicals in the water were copper, lead, and Polynuclear Aromatic Hydrocarbons (PAHs). While metals remain after ozonation, the concentrations of some organics were greatly reduced.