Monitoring storm water discharges with Total Organic Carbon (TOC)

Managing storm water at large industrial production sites requires straightforward monitoring in order to decide whether such water may be discharged into the environment or whether it needs to be collected in tanks or ponds for further treatment. The application (AN-PAN-1021) presented in this Application Note suggests online monitoring of TOC as a suitable technology to make such decisions and prevent pollution events.

Many industrial production sites, in particular chemical and petrochemical sites, cover large surface areas that often include storage areas and tank farms for raw materials and the commodities produced. These sites are surrounded by storm water ditches that collect run off water during periods of heavy rain. Under normal conditions this storm water is permitted to be discharged directly into the environment. However, if there has been a spillage of contaminating nature, the storm water will have a polluting effect on the receiving water body. Therefore it will have to be diverted to holding tanks and fed at an appropriate rate to the site’s water treatment plant for further treatment prior to discharge.

An online Total Organic Carbon (TOC) Analyser such as the ADI 7010 from Metrohm Applikon can continuously screen run off water that is collected by the storm water ditches. If the level of TOC monitored exceeds the permissible level (for example 50 mg/L) for discharge, an alarm signal is triggered to divert the storm water flow to the holding tank. A level switch incorporated into the sample fast loop reservoir will put the analyser into standby mode during periods of low flow. Details on this application are available from Metrohm Applikon.