The role of calcium chloride in sewage treatment

First of all, sewage treatment methods mainly include physical treatment and chemical treatment. The physical method is to use various filter materials with different pore sizes and use adsorption or blocking methods to exclude impurities in the water. The most important adsorption method is activated carbon adsorption. The blocking method is to pass the water through the filter material to allow the volume Larger impurities cannot pass through, resulting in cleaner water. In addition, physical methods also include precipitation methods, which are to allow impurities with a smaller specific gravity to float on the water surface and fish them out, or to obtain impurities with a larger specific gravity by settling below. Chemical methods use various chemicals to convert impurities in the water into substances that are less harmful to the human body, or to concentrate the impurities. The oldest chemical treatment method is to add alum to the water. After the impurities in the water are gathered, the volume becomes larger. , impurities can be removed by filtration.

In sewage treatment, chemicals such as calcium chloride are often used. It is an inorganic compound, a salt composed of chlorine and calcium, and is a typical ionic halide. Chloride ions can sterilize and disinfect water, kill harmful bacteria, and weaken the toxicity of water. Calcium ions can replace metal cations contained in water, separate and eliminate toxic heavy metal ions, and precipitate and eliminate calcium ions, which has a good disinfection and purification effect. The following is an introduction to the specific role of calcium chloride in sewage treatment:

1.The chloride ions produced after calcium chloride is dissolved in water have the effect of sterilization and disinfection.

2.Calcium ions can replace metal cations in the water, especially in the treatment process of wastewater containing metal cations. In order to reduce the damage of metal cations and highly toxic substances to the biochemical section, calcium chloride is used during the pretreatment process to remove these toxic and harmful substances. It plays a key role. If this substance is used in the water outlet section, chloride ions play a sterilizing role. Calcium ions generate calcium hydroxide and are precipitated and removed.

3.Perform PH neutralization and pre-condition acidic sewage pipe network to extend the service life of the pipe network.

Specific application process: After the wastewater is collected, it enters the regulating tank. The wastewater is lifted into the coagulation tank by a lifting pump. The coagulation tank is divided into two processes, slow mixing and fast mixing, with a total of four stages of reaction. A dosing pump is used in the fast mixing tank. Add sodium hydroxide to adjust the pH of the mixed water in the pool to 8. At the same time, add polyaluminum chloride and calcium chloride with better water solubility. After sufficient reaction, the wastewater enters the slow mixing tank; in the slow mixing tank, by adding The flocculant polyacrylamide causes the formed calcium chloride particles to coagulate with each other to form larger particle flocs; after flocculation, the effluent flows into the sedimentation tank and achieves solid-liquid separation through natural sedimentation. After the supernatant overflows from the upper part of the sedimentation tank Artesian flow enters the secondary coagulation and sedimentation; the water after secondary coagulation and sedimentation treatment passes the bag filter-activated carbon filter and is discharged into the owner's acid-base neutralization tank after the pH value is adjusted. Efflux. Unqualified water is discharged into the regulating tank before being processed.