Hydrogen Sulfide or H2S is a common gas that you can find in utility facilities, wastewater treatment, and sewers. Also, they are commonly found while drilling and producing crude oil. Hydrogen Sulfide gas is produced in absence of oxygen and due to the breakdown of organic materials.
Besides, H2S is recognized by its rotten egg smell. Also, the gas is corrosive, poisonous, flammable, and colorless. Apart from that, H2S gas prevents cellular respiration in humans. Because of its similar toxicity to carbon monoxide, hydrogen sulfide gas can be the deciding factor between life and death.
The short and long-term impact of H2S on safety and health
Hydrogen Sulfide gas remains undetected to the body’s senses. The primary cause of exposure to this deadly gas is inhalation. Although many people can smell the gas in small concentrations, frequent exposure to the gas even in low amounts eliminates the sense of smell.
Moreover, high-level exposure to the gas eliminates the sense of smell almost instantly. This gas irritates the respiratory tract and mucous membranes of the body. Short-term exposure symptoms include skin and eye irritation, convulsions, nausea, and headache. Serious exposure may impact the central nervous system.
At much higher concentrations, a person can only breathe for some time to induce unconsciousness, respiratory paralysis, seizures, coma, and even death. However, H2S gas doesn’t accumulate inside the body.
But prolonged to moderate exposure can result in low blood pressure, weight loss, loss of appetite, and headaches. Besides, prolonged exposure of the gas to low levels can cause irritated eyes and painful skin rashes.
Treatment of H2S poisoning
The first step involved in H2S treatment includes removing the victim from the toxic environment quickly. Besides, rescuers have to maintain caution when they approach the victims because they could hurt themselves from the exposure.
When entering into a toxic environment, respiratory protection is a must because of the toxic effects of the gas. While there are no antidotes for H2S poisoning, the symptoms and side effects are manageable and treatable. Moreover, in serious cases, victims should be hospitalized.
Visit the emergency or call a doctor if someone develops unusual symptoms or side effects within 24 hours of the incident. Remain vigilant and never try to avoid safety programs. Also, gas detection equipment should be calibrated and bump tested frequently and regularly.
How to remove H2S gas from biogas?
The concentration of the components present in biogas has a significant impact on the user. Although boilers can absorb concentrations of hydrogen sulfide to up to 1000ppm and low pressure, internal combustion engines can operate below 100ppm.
The common methods for H2S removal from biogas are biological desulphurization and iron chloride dosing.
- Biological desulphurization – For the oxidation of sulfide, adequate amounts of oxygen should be added to the biogas. Depending on the concentration of the gas, it should have at least 2 to 6% air in the biogas.
- Iron chloride dosing – Iron chloride is fed to the digester slurry where it reacts with H2S to form iron sulfide salt. The method is effective in reducing H2S gas in higher amounts. However, it is less effective in attaining stable and low levels of H2S.