When wastewater contains elements such as iron (Fe), sulfur (S), silicon (Si), etc., different treatment methods can be adopted to remove these contaminants. Here are some common ways to deal with it:
1.*Removal of iron (Fe)**:
Chemical precipitation**: Fe is oxidized to Fe by the addition of oxidants (e.g., chlorine, hydrogen peroxide) and then precipitants (e.g., lime, sodium hydroxide) to form Fe(OH) precipitate.
Ion exchange**: Ion exchange resins are used to remove iron ions from water.
Membrane separation technology**: Iron ions are removed by nanofiltration, reverse osmosis and other membrane technologies.
2.*Removal of sulfur(s)**:
Oxidation**: Oxidation of sulfur compounds to sulfates, which are then removed by precipitation or filtration.
Precipitation**: Metal salts (such as iron or aluminium salts) are added to form a precipitate with sulfur.
Air stripping**: For dissolved hydrogen sulfide (Hs), it can be blown out of the water by means of air stripping.
3.*Removal of silicon (Si)**:
Ion exchange**: Ion exchange resins are used to remove silicate ions from water.
Membrane separation technology**: Removal of silicate ions through nanofiltration, reverse osmosis and other membrane technologies.
Chemical precipitation**: Under certain conditions, silicate ions can react with calcium or aluminum ions to form insoluble silicate precipitates.
In practical applications, a combination of methods may be required to effectively remove iron, sulfur, and silicon from wastewater. In addition, the sediment and sludge generated during the treatment process need to be properly disposed of to avoid secondary pollution to the environment. The choice of treatment technology should be based on the specific composition of the wastewater, the characteristics of the water quality, the cost of treatment and the environmental protection requirements. At the same time, the treatment process should follow relevant environmental protection regulations and standards to ensure the treatment effect and protect the environment.