Removal of Heavy Metals: Sodium Sulphide is used in water treatment plants for the removal of heavy metals from wastewater. It reacts with metal ions such as cadmium, copper, and zinc, forming insoluble metal sulphides that can be precipitated and removed from water through filtration or sedimentation processes.

Odor Control: In certain water treatment applications, Sodium Sulphide is employed for controlling odors caused by hydrogen sulfide (H2S) gas. Sodium Sulphide reacts with hydrogen sulfide, converting it into less odorous compounds, thereby improving the overall odor quality of treated water.

Precipitation of Sulfides: Sodium Sulphide is utilized for the precipitation of sulphide compounds in water. It facilitates the removal of sulphur-containing compounds, including mercaptans and sulfides, which can cause environmental issues and affect water quality.

Reducing Agent: As a reducing agent, Sodium Sulphide can be used to treat oxidized water sources. It helps reduce the oxidation state of certain pollutants, making them easier to remove through subsequent treatment processes.