CONTINUOUS ANALYSIS AND MONITORING OF VOCS IN WATER AND WASTEWATER SAMPLES FOR INDUSTRIAL PROCESSES
Introduction Today more than ever, environmental health is of great concern to everyone, from politicians and scientists to the general public. All organizations must recognize the importance of protecting our ecosystems. Prosecution for polluting the environment cannot only lead to expensive fi nes, but can also result in a company’s image and subsequent devaluation.
Water utility companies, industries with their own wastewater treatment plants, and petrochemical industries are recognizing the importance of pollution control. These organizations are investing in high-detection technologies and monitoring equipment, not only for clean water intake, but also for wastewater treatment that ensures water quality is acceptable before it is returned to nature.
Figure 2: Purge and Trap system
VOCs contribute up to 10% of the total dissolved organic carbons in relatively unpolluted water and represent a much greater proportion in water used for industrial processes (Huybrechts et al., 2003). There are numerous analytical methods for the characterization of VOCs in water and liquids that have been reviewed by Chary and Fernandez-Alba, 2012. The analysis of dissolved VOCs in wastewater, drinking water and liquids from industrial processes is not a simple issue due to the complexity of the matrix in which there are present and also by the range of concentrations to be measured. To ensure water quality and to help regulating industrial processes, cost-effective continuous automatic monitoring systems are needed.
Figure 1: airmoVOC WMS Analysis of trace level VOCs in water using airmoVOC WMS
With a long history in gas chromatography, Chromatotec® provides several analytical solutions, including liquid sample handling for the measurement and quantifi cation of VOCs and BTEX (Benzene, Toluene, Ethylbenzene and Xylene) in liquid
IET SEPTEMBER 2022
samples. The airmoVOC WMS (Figure 1) is an Mcerts-certifi ed gas chromatograph that has already proven its suitability for VOCs and BTEX analysis in liquid samples. Depending on the concentration range of the sample, the solution can be tailored to accommodate from µg/L to g/L concentrations. In this paper, we describe three different technics for the measurement of dissolved VOCs in drinking water, wastewater and industrial solvents.
The analysis of VOCs at a trace level in water is performed using an automated thermodesorption gas chromatograph equipped with a fl ame ionization detector (auto-TD-GC/FID) and a specifi c sampling system following the US EPA 502.2 method, for the extraction of VOCs from water liquid sample (Purge and Trap).
The Purge and Trap system consists of an automatic sparger to extract VOCs from liquid samples in 11 minutes (Figure 2). The loop is fi lled with 5 ml of the liquid sample by a pump and then
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