Sulfur-containing waste water is a type of toxic waste water containing sulfides. Such waste water has a strong sulfuric smell and is also corrosive. The chemical flocculation treatment method is applicable to various kinds of sewage treatment, and has a high removal rate of sulfur-containing wastewater from the suspended solids in the wastewater. The typical chemical treatment method is to add ferrous sulfate. Ferrous sulfate is not only a flocculant but also a reducing agent. Then, in the treatment of sulfur-containing waste water, is ferrous sulfate used as a flocculant or a reducing agent?
Ferrous sulfate precipitation treatment of sulfidation wastewater
Unlike polyferric sulfate, ferrous sulfate dissolves in water and generates a large amount of divalent iron ions. These divalent iron ions react with negatively charged trivalent sulfur ions in water to form ferrous sulfide deposits. After the oxidation of air to produce iron sulfide precipitation. The purpose of desulfurization is achieved by solid-liquid separation treatment of these precipitates.
When using ferrous sulfate for desulfurization, it is generally required to add an excessive amount of ferrous sulfate. In the application, if the content of sulfur ions in the wastewater is 0.8 mg/L, the dosage of ferrous sulfate is 30 mg/L, and the desulfurization rate of the wastewater can reach 99%.
In the sulfur-containing waste water sedimentation process, ferrous sulfate is used as a precipitant, and ferrous sulfate can react with sulfide ions to convert it into insoluble sulfide precipitates. However, this method has the disadvantage that the reaction of ferrous sulfate is generated. Sodium sulfide is relatively small, and it is necessary to add auxiliary flocculant. Otherwise, it is necessary to increase the amount of ferrous sulfate added to cause waste of cost.
Sulfur-containing wastewater is treated with a precipitant such as ferrous sulfate, neutralization method, chlorination method, steam stripping method, aeration method, oxidation method, etc., and is specifically determined according to the concentration of sulfur in wastewater. Which method is more appropriate and economical?