Cooling Tower Water Testing - Not the same old El Paso Method

In the early 70's, the El Paso Products Company devised a cost effective method to sample for VOC's in the cooling water. This method utilized a dynamic or flow-through system for air stripping a sample of the water and analyzing the resultant off-gases for VOC's using a common flame ionization detector (FID) analyzer, and has been required in permits in Texas for many years.

The El Paso Products method, however, has been overshadowed nationally by the use of purge and trap analysis of water samples utilizing gas chromatography and/or mass spectrometry techniques. While direct water analysis has been shown to be effective for cooling tower measurements of heavier molecular weight organic compounds with relatively high boiling points, Texas Commission on Environmental Quality (TCEQ) has determined that this approach may be ineffective for capture and measurement of volatile organic compounds with lower boiling points, such as ethylene, propylene, 1,3-butadiene, and butenes. VOC's with a low molecular weight and boiling point are generally lost in the sample collection step of purge/trap type analysis. Consequently, TCEQ requires that the air stripping method presented in Appendix P of the TCEQ Sampling Procedures manual be used for cooling tower and other applicable water matrix emission measurements of VOC's with boiling points below 140o F.

This test method had been review and accepted by the Texas Environmental Department currently known as Texas Commission on Environmental Quality (TCEQ). This method was accepted for analyzing samples for any VOC's that may come in contact with the cooling water. As of January of 2003, the TCEQ has adopted a new modified El Paso method. This method has taken an EPA methodical approach to testing. In this modified method certain criteria have to be met before this method can be utilized and a QA/QC procedure has been added which was not provided in the previous El Paso method.

Previously, the FID analyzer that was utilized could be of analog type readouts that were design to read much higher concentration and not design to measure the lower concentration levels typically found in cooling water. FID analyzers used in conjunction with the new method must be a digital readout (readable to 0.1 ppmv), must be able to calibrate to low methane concentrations (e.g. 5, 10 ppmv) and have a sampling rate less than 2000 ml/min. The QA/QC section of the method now requires semi-annually calibration of specific components of the cooling water tower apparatus. These components are: air rotameter, water rotameter, and the temperature gauge. To calibrate these components, specialized equipment should be purchased to accomplish these tasks.

EnRUD Resources, Inc. has the experience and the equipment to perform the necessary QA/QC on the cooling tower water apparatus and the knowledge to perform cooling tower water testing with the procedure incorporated in the TCEQ sampling procedures manual. EnRUD now offers this testing service through the Compliance Assistant Division (CAD). The Compliance Assistance Division will provide a turnkey solution from testing to reporting of calculated mass emissions from cooling tower. If data dictates that samples be speciated periodically, EnRUD Resources, Inc. will provide a 3rd party laboratory or provide samples to the facilities in-house laboratory. Stay tuned for more exciting news as EnRUD Resources, Inc. begins to automate the data acquisition process of cooling tower testing. In the near future we will have a pen-based data acquisition solution that will automate the testing process preventing the need for paper in the field. Customers or contractors will be able collect the information in the field electronically and up-load the information to a PC based data management system. This allows the customer to perform calculations and reports at the touch of a button. For more information on Cooling Tower Water Testing.

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