1. The precipitation method is used to settle and clarify the impurities and silt in the water with large particle size, so as to settle and clarify the water in the sedimentation tank, so as to obtain the water with less turbidity and achieve the initial purification purpose.
2. Filtration method can be used to remove insoluble impurities that can not be removed by subsidence in water.
The filtering method includes sand filtration method, sand filter method and sand filter stick method.
3, adsorption, adsorption is the use of adsorbent (strong adsorption ability) and one or more pollutants in the water adsorption, through sedimentation or filtration should be dropped from the water.
The method has the advantages of low cost, simple operation, reusable adsorbent and selectivity.
The adsorbent can be divided into activated carbon adsorbent, active oxide adsorbent, silica gel adsorbent, synthetic zeolite adsorbent and activated clay adsorbent.
At present, this method is widely used in the treatment and recycling of printing and dyeing wastewater, and the representative adsorbent is activated carbon.
In recent years, the introduction of graphene materials has been remarkable.
Graphene huge specific surface area makes it a good adsorbent, it is mainly used for organic matter and inorganic anion adsorption , but the hydrophobic and aggregation of the graphene itself limits its application in water treatment, development of hydrophilicity and biocompatibility of graphene composite material, is a new research direction of graphene materials.