Industry: Environmental
Instrument: Velocity XPT
Evaluation of a New Purge and Trap On-line Interface for the Real-Time Analysis of VOCs in Aqueous Streams
Purge and Trap has been used for nearly thirty years as the technique of choice for the analysis of trihalomethane disinfection by-products in finished water for drinking water treatment. Large drinking water treatment facilities have dedicated laboratories to perform this analysis on grab samples routinely. However, it is not common to analyze the raw intake water, prior to treatment for contaminants, that could overwhelm the treatment process and result in unsafe levels of contaminants in the finished water. The Ohio River Valley Water Sanitation Commission (ORSANCO) has been operating an organics detection system (ODS) on the Ohio river since 1978. This program provides daily analyses of river water for the presence of certain organic compounds. If unusual levels are detected, downstream water utilities are notified and efforts are undertaken to determine the source.1 After 9/11, and the passing of the Public Health Security and Bioterrorism Preparedness and Response Act, the need for an automatic system for monitoring raw water for contaminants increased. Even without the added concerns of deliberate malicious contamination, highly industrialized surface waters that serve as public drinking water sources become routinely contaminated with volatile organic compounds (VOCs). In 2002 ORSANCO reported over 300 organic spills on the Ohio River. While most spills are petroleum-based fuels at low levels, hazardous VOCs are found at levels that, without proper precautions, could affect the purity and safety of the finished drinking water.
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