Can Stainless Steel Ball Valves Be Used In The Sewage Treatment System? 

Water pollution is a very serious problem in the world. Due to people's attention to the sewage treatment, the importance of stainless steel ball valves in the sewage treatment system has been emphasized more. Therefore, we will share some knowledge about the valves in the sewage treatment system.

1. Definition of the Sewage Treatment

Sewage treatment refers to the purification process of the sewage to meet the water quality requirements of discharging into other water source or reusing in other industries. Sewage treatment is widely used in construction, agriculture, transportation, energy, petrochemical, environmental protection, urban landscape, medical, catering and other fields. It is also gradually known by people and comes into our daily life.

2. Classification of the Sewage Treatment

2.1 Classification by Source

Sewage treatment is generally divided into production sewage treatment and domestic sewage treatment. Production sewage includes industrial sewage, agricultural sewage and medical sewage. Domestic sewage is the sewage produced in daily life, which refers to the complex mixture of various forms of inorganic and organic substances. It mainly consists of floating and suspended solid particles, colloidal and gelatinous diffused substances and pure solutions.

2.2 Classification by Nature

The sewage can be divided into two categories, namely to say, natural pollution and man-made pollution. At present, man-made pollution is the most harmful sewage to the natural water source. According to the different pollution impurities, water pollution can be divided into chemical pollution, physical pollution and biological pollution. There is a variety of pollutants, such as untreated industrial sewage and domestic sewage, farmland sewage containing a lot of chemical fertilizers and pesticides, industrial and domestic waste heaped along the river and soil erosion and so on.

3. Valves of the Sewage Treatment

3.1 Primary Treatment

Primary treatment mainly removes the suspended solid pollutants in the sewage. Most of the physical processing methods can only meet the requirements of the primary treatment. After the primary treatment of the sewage, BOD can be generally removed about 30%, but it can not meet the discharge standard of the sewage treatment. In fact, the primary treatment belongs to the pretreatment of the secondary treatment. The valves and pipe fittings used in the primary treatment include knife gate valves, three eccentric butterfly valves, filters, etc.

3.2 Secondary Treatment

It is mainly used to remove organic pollutants in colloidal and dissolved state. The removal rate can reach more than 90%, making the organic pollutants meet the emission standard of the sewage treatment. The removal rate of suspended solids can even reach 95%. Additionally, the valves include soft and sealing butterfly valves, gate valves, stainless steel ball valves, stop valves, etc.

3.3 Tertiary Treatment

The tertiary treatment is to further treat the refractory organic substances, nitrogen and phosphorus that can lead to eutrophication of water. The main methods are biological denitrification and phosphorus removal, coagulation and sedimentation, sand filtration, activated carbon adsorption, ion exchange and electrodialysis and so on. Various valves are used in this step, such as wafer butterfly valves, gate valves, stainless steel ball valves, stop valves, etc.