Manchester, UK Specialist electrochemical sensor manufacturer Analytical Technology Inc. announces that its Q45S dissolved hydrogen sulphide monitor is capable of achieving, breakthrough measurement for odour control applications at a relatively low cost. Odour has been a long standing issue in waste water treatment but ATi’s new electrochemical sensor technology allows economica breakthrough monitoring which meets legislative limits for most waste water treatment plants. The DEFRA code of practice (http://www.defra.gov.uk/publications/files/pb11833-sewageodour-cop.pdf) provides the legislative framework and gives guidelines to control strategies. A key part of many odour control processes is to contain the air and then collect it and clean it using a gas scrubber that removes H2S from air streams using chemical, dry media or biological processes. H2S removal in wastewater treatment plants and sewage collection systems often requires the use of scrubber technologies to remove H2S from air streams prior to discharge. Historically, monitoring the hydrogen sulphide in discharge air has presented problems for standard sulphide gas sensors but ATi have effectively overcome the issue. ATi have developed sensor technology that now allows in situ continuous monitoring in this type of application.


Traditional manual laboratory techniques based on analysing extracted air samples can provide information with accuracies in the range of 0.1ppm however these are time consuming methods. On line monitoring to these levels requires very expensive monitoring equipment, totalling a costly £15000. Unlike ATi’s Q45S monitor, the techniques are not continuous and demand good sampling. Analytical Technology’s wet stack Q45S monitor removes the need for sample conditioning as its electrochemical sensor is conveniently installed directly into the stack, measurements can 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 . Given that the Q45S system often monitors 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 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.


In normal use an outlet monitor will read 0.05ppm to 0.2000ppm and at these levels, there is great confidence the scrubber is working correctly. In the event of a breakthrough, the reading on an ATi instrument will rise rapidly and alarms will be activated before legislation limits are reached. At such a low cost, complete with installation and commissioning, the ATi electrochemical sensing technology really does provide economical, reliable breakthrough monitoring. For further information on the Q45S monitor contact Vicky Wilshaw/Mike Strahand of Analytical Technology on 0800 8042 062, sales@atiuk.com or visit http://www.atiuk.com.