H2s Monitor for Wets Scrubbers

Odour control in wastewater treatment plants and sewage collection systems often requires the use of scrubber systems. Many of these scrubbers employ a wet process using hypochlorite solution to remove H2S from air streams prior to discharge. Monitoring the hydrogen sulphide in both inlet and discharge air has presented problems for standard sulphide gas sensors. ATI has developed sensor technology that now allows continuous monitoring in this type of application, where condensing humidity conditions are normal. The Q45S monitoring system uses a special "Wet H2S" sensor. Measurements may be made either at the inlet to scrubber systems where concentrations can run as high as 200 PPM, or at the outlet where concentrations are ideally down below 0.5 PPM. Special sensor configurations are available for either duct insertion or flowcell use. Because Q45S systems are often monitoring gas streams with condensing levels of water vapour, provision has been made for eliminating water droplets from the sensor that could present a barrier to the diffusion of H2S into the sensor. An optional air-purge system controlled by the transmitter will periodically deliver a blast of air across the critical sensor surfaces to remove water droplets. This system insures a clear gas diffusion path to the sensor and reliable measurements on a continuous basis.

A battery-powered version of the Q45S is available for use in temporary installations. This system runs on an internal 9 volt battery and contains a data-logger for collecting information on existing air collection systems. A standard 9 volt battery will operate the unit for 4 days, while a 9 volt lithium battery will provide about 10 days of operation. Data is easily downloaded to a standard PC using software supplied with the unit.