Colorimetric Analyser Monitors Hazardous Chromium VI in Drinking Water

Municipal water treatment engineers who must monitor chromium VI in drinking water will find the  CA6 Colorimetric Analyser from Electro-Chemical Devices (USA) provides precise and dependable measurement to ensure compliance with local, state and federal drinking water standards.

According to the U.S. Environmental Protection Agency (EPA), chromium is an odorless and tasteless metallic element that is found naturally in rocks, plants, soil and volcanic dust, and animals. The most common forms of chromium that occur in natural waters in the environment are trivalent chromium (chromium III) and hexavalent chromium (chromium VI.)

Chromium III is an essential human dietary element. It is found in many vegetables, fruits, meats, grains, and yeast. Chromium VI occurs naturally in the environment from the erosion of natural chromium deposits, but it also can be produced by industrial processes. There are demonstrated instances of chromium being released to the environment by leakage, poor storage, or inadequate industrial waste disposal practices.

To ensure the greatest potential chromium risk is addressed, the U.S. EPA's assumes that a measurement of total chromium is 100 percent chromium VI, the more toxic form. If tap water from a public water system exceeds this federal standard, consumers will be notified.

The Model CA6 Colorimetric Analyzer from ECD is an on-line sequential sampling analyser that is designed to monitor Chromium VI in drinking water. It can be configured to measure Chromium VI in three separate ranges: 0 to 1.0 mg/L, 0 to 10.0 mg/L or 0 to 50.0 mg/L

The CA6 Colorimetric Analyser’s sequence of sampling, analysis and results processing is performed and repeated using colorimetric methods for high accuracy and reliability. This technology relies on an LED light source and a heated colorimetric cell designed for measuring trace amounts of manganese, iron and other analytes in water.

The CA6 precision online sequential sampling analyser is lightweight and easy to install. Weighing less than 40 pounds, it can be wall mounted or simply set on a bench using the optional bench top stand. After the sample, waste and reagent lines have been connected to the analyser and provided with power, the CA6 will begin its preprogrammed analysis sequence. The CA6 is available with up to 4 channels (optional) each from a separate sample point. A simple, user-friendly menu structure and touchscreen interface makes it easy to access information or customise analyses.

The CA6 utilises photometric differential absorbance to analyse chromium VI and over 20 other common parameters including: aluminum, iron, manganese, silica, nitrogen, iron and sulfate. It operates at a wide temperature range of 5-50°C and  offers repeatability of ±2% on the absorbance value if the turbidity <80 NTU and drift of ±2% per month on the absorbance measurement.

The CA6 Analyser’s easy-to-use touch-screen display shows the measured parameter, analyzer status, percent reagent volumes and the menu bar, which provides access to the run, display, program, service and help menus. It includes two alarm relay outputs and a 4-20 mA channel that connects with programmable logic controllers (PLC’s) or distributed control systems (DCS’s).

The rugged and reliable CA6 features two separate compartments to isolate liquids and electronics and is enclosed in an epoxy powder coated, cold rolled steel cabinet. The liquids enclosure houses all the components necessary for sampling and reagent flow, mixing and reaction stages (sampling pump, reagent micro-pumps and colorimetric reaction cell).