monitoring of tanks and sewage manholes

Descriptions of accidents in sewage sumps show that seemingly simple operations can be deadly dangerous because they accumulate heavier gases than air – carbon dioxide, methane and hydrogen sulfide. The content of each of these gases in the air is very dangerous for humans: carbon dioxide displaces oxygen from the respiratory system and a few breaths lead to loss of consciousness. Methane causes general anesthesia of the body. Very powerful hydrogen sulfide, in high concentrations – even with one inhalation, causes respiratory paralysis and death.