With the increasing world population and the unavoidable effect it has on the environment, the proliferation of wastewater treatment plants is happening throughout the globe. Wastewater treatment processes use and produce a variety of highly toxic and combustible gases that necessitate close monitoring to ensure the safety of personnel, equipment, and - to a larger extent - the environment.
Hydrogen sulphide (H2S) is an extremely toxic gas that is both naturally present and produced in wastewater treatment. During the initial stages of treatment, it is found in raw sewage. It is also present throughout the processing of sludge (primary sludge, return activated sludge, waste activated sludge, and thickened sludge). As a result, it is important to monitor for H2S in sewers, sludge de-watering systems, anaerobic digesters, and wet/dry wells.
Methane, or natural gas, is a highly flammable gas produced in wastewater treatment, mostly in the stages of sludge decomposition. It is present in raw sewage and sludge that enters de-watering systems, and is even more abundant in anaerobic digesters, cogeneration facilities (where the methane is used to power the treatment facility), and wet/dry wells.
Much like wastewater treatment plants, Methane can also be found at landfill vapor recovery sites that use the methane emitted from decomposing materials to fuel compressors, engines, and cogeneration plants.
Oxygen, which should be kept at adequate levels for health purposes, is also affected by the various chemical and organic processes that occur in any wastewater treatment plant. It is important to locate oxygen deficiency monitors in enclosed areas where oxygen levels may be compromised.
Ammonia (NH3), ozone (O3), and chlorine (Cl2) are all used in the decontamination stage of wastewater treatment and water purification plants. Locating monitors in or near the storage areas of these extremely toxic gases would help ensure that personnel do not come into contact with dangerous concentrations of them.
