What is Hydrogen Sulphide
Hydrogen sulfide is a colorless, flammable, extremely hazardous gas with a “rot- ten egg” smell. Some common names for the gas include sewer gas, stink damp, swamp gas and manure gas. It occurs naturally in crude petroleum, natural gas, and hot springs. In addition, hydrogen sulfide is produced by bacterial break- down of organic materials and human and animal wastes (e.g., sewage). Industrial activities that can produce the gas include petroleum/natural gas drilling and refining, wastewater treatment, coke ovens, tanneries, and kraft paper mills. Hydrogen sulfide can also exist as a liquid compressed gas.
Reduction of Sulphate to Sulphide
In water, at pH 7, about 50% of the dissolved sulphide converts to H2S gas.
Corrosive
Biogenic sulphide corrosion is a bacterially mediated process of forming hydrogen sulphide gas and the subsequent conversion to sulphuric acid that attacks concrete and steel within wastewater environments. The hydrogen sulphide gas is biochemically oxidized in the presence of moisture to form sulphuric acid. The effect of sulphuric acid on concrete and steel surfaces exposed to severe wastewater environments can be devastating. In the USA alone, corrosion is causing sewer asset losses estimated at around $14 billion per year. This cost is expected to increase as the aging infrastructure continues to fail.
Poisonous
Beginning of Eye Irritation
10 ppm
Slight conjunctivitis and respiratory tract irritation after one hour
50-100 ppm
Coughing, eye irritation, loss of sense of smell after 2-15 minutes. Altered respiration, pain the eyes, anddrowsiness after 15-30 minutes followed by throat irritation after one hour. Several hours exposure results ingradual increase in severity of symptoms and death may occur within the next 48 hours.
100 ppm
Marked conjunctivitis and respiratory tract irritation after one hour exposure.
200-300 ppm
Loss of consciousness and possibly death in 30 minutes to one hour of exposure.
500-700 ppm
Rapid unconsciousness, cessation of respiration, and death
700-1000 ppm
Unconsciousness at once, with early cessation of respiration and death in a few minutes. Death may occur if individual is removed to fresh air at once.
1000-2000 ppm
ODOUR CONTROL
Chemical Treatment
Dosing and Storage
Equipment
