Water Treatment with Sodium Nitrite

Water treatment involves the use of many chemicals.

Water treatment includes the use chemicals including biocides, algaecides, coagulants, disinfectants, neutralizing agents, pH conditioners, and corrosion inhibitors. Sodium Nitrite is a corrosion inhibitor, but has uses beyond this in water treatment.

Heating and Cooling Systems

For any closed cooling or heating system where the heat exchange fluid is completely contained within the system, corrosion of pipes and metal surfaces can be a serious problem. For systems that have steel pipes, sodium nitrite is commonly used as an additive. It forms a protective film of iron oxide on the metal surfaces.

Odor Control for Wastewater

Sodium nitrite has other uses in water treatment. The Johnstown, Pennsylvania Wastewater Treatment Plant had a chronic hydrogen sulfide odor problem. It was found that the addition of a blend of sodium nitrite and sodium nitrate to the waste sludge has produced a tenfold decrease in hydrogen sulfide and made working conditions more comfortable.

Considerations

As with many chemicals, sodium nitrite is toxic in concentrated form. It is a strong oxidizing agent with a risk of fire or explosion in contact with other materials. It can be harmful if swallowed, inhaled, or absorbed through the skin, and can cause irritation to eyes, skin, and the respiratory tract. For this reason, care must be taken when handling the substance.

References

• Lenntech: Water Treatment Chemicals
• Spartan Water Treatment: Need for Cooling Water Treatment
• Water and Wastes Digest: Treatment Plant Cuts Hydrogen Sulfide Odor With Sodium Nitrite/Nitrate Blend
• J. T. Baker: Sodium Nitrite