USACE Awards NexSens 5-year Contract for H2S Monitoring Sites

Concrete outlet tunnels

The US Army Corps of Engineers (USACE) renewed a five-year contract for NexSens Technology to continue servicing real-time hydrogen sulfide gas (H2S) monitoring sites in northeast Ohio, lasting until 2011.

The permanently installed sites are located at Tappan, Atwood, Leesville, Piedmont and Clendening reservoirs. NexSens field engineers maintain the sites from May to October, with monthly site visits for calibration and inspection.

H2S gas is commonly formed during warm weather when runoff from coal mines with high sulfate concentrations mix with water from lake bottoms. Many of the Muskingum reservoirs have become problem areas for emitting H2S gases as a result of improper restoration of strip-mined land prior to the Surface Mining Control and Reclamation Act of 1977.

H2S, a colorless, flammable gas that smells like rotten eggs, is a hazardous substance to both people and the environment. When exposed to even low levels of hydrogen sulfide gas, people can experience eye irritation, a sore throat and cough, shortness of breath, and fluid in the lungs.

The NexSens H2S monitoring systems were installed in 2003 at the reservoir's concrete outlet tunnel, where water with high hydrogen sulfide concentrations is routinely released. ATI B12-24 Hydrogen Sulfide Transmitters continuously monitor H2S levels. These transmitters are connected to NexSens iSIC data loggers with radio telemetry.

Wireless real-time data transmission allows USACE personnel to know H2S levels without entering the potentially dangerous area with a handheld meter. At low concentrations (less than 10-20ppm) the gas has a rotten egg odor. However in greater concentrations (150-250ppm or greater) the gas loses its smell and can go undetected, which means there is no warning sign of the eminent danger.

For more information on the latest in environmental data logging and software technology, contact Paul Nieberding at 937.426.2703.