Polyaluminum chloride (PAC) is a commonly used chemical coagulant in wastewater treatment. It has excellent flocculation and sedimentation effects, and is widely used in various sewage treatment scenarios.
PAC is a highly efficient inorganic polymer coagulant, the main components of which are composed of aluminum ions and chloride ions. The chemical formula of PAC can be expressed as (Aln(OH)MCL3N-M)X, where N and M are polynomials. The solid form of PAC is mostly a pale yellow or light brown solid powder.
The use of PAC for wastewater treatment has the following advantages:
The main role of PAC in sewage treatment is coagulation and sedimentation. Its mechanism of action is as follows:
The aluminum ions (Al3+) in the PAC can form an insoluble precipitate with the sulfite ions (HSO3-) in the water, which fixes the impurities in the wastewater.
The chloride ion (Cl-) in the PAC can react with hydrogen sulfide (H2S) in the water to form the precipitation of sulfides (such as Fes, Cus, etc.), which plays a role in deodorization.
The aluminum ions in the PAC can also be charged neutralized with colloidal substances and tiny suspended solids in the wastewater, and form large particles of flocs, which facilitate the subsequent precipitation separation.
When using PAC for wastewater treatment, the following steps can generally be followed:
According to the water quality of the wastewater, the appropriate PAC dosage is determined, which can be adjusted according to the test results in actual operation.
Dissolve the PAC solid powder in an appropriate amount of clean water to make a PAC solution.
The PAC solution is evenly added to the sewage and stirred sufficiently to promote the full contact and reaction of the PAC with the impurities in the wastewater.
After a certain period of coagulation and precipitation, subsequent solid-liquid separation or filtration processes can be carried out to separate the flocs in the turbid liquid and purify the wastewater.
PAC is widely used in various wastewater treatment scenarios, including but not limited to:
When using PAC for wastewater treatment, the following things need to be noted:
According to the actual situation, select the appropriate PAC model and dosage to get the best treatment effect.
Pay attention to the storage and transportation conditions of the PAC and avoid exposure to the sun and moisture.
When using PAC, it is necessary to avoid mixing with other chemicals to avoid adverse reactions.
In the process of using the PAC, it is necessary to do a good job in the cleaning and maintenance of the corresponding sewage treatment equipment.
As a commonly used coagulant for sewage treatment, PAC has been widely used in various fields with its efficient flocculation and sedimentation properties. In the process of sewage treatment, the correct use of PAC can effectively remove pollutants from wastewater and protect the safety of the environment and water resources. Therefore, the understanding and reasonable application of PAC is an important part of sewage treatment engineering.