Flocculants play an important role in wastewater treatment, helping to aggregate suspended particles into larger particles, thereby facilitating subsequent sedimentation and filtration. The following is the application process of flocculants in sewage treatment:
Mixing and dosing: Flocculants usually exist in the form of powder or liquid. Firstly, it is necessary to mix the flocculant with an appropriate amount of water to form a uniform suspension. Then, the flocculant suspension is added to the sewage through appropriate equipment.
Rapid mixing: After the flocculant is added to the sewage, it needs to be thoroughly mixed through a rapid mixing device (such as a stirrer) to ensure that the flocculant contacts and acts on suspended particles in the sewage. This process usually lasts for a few minutes.
Slow mixing: After rapid mixing, the sewage will enter the slow mixing area. In the slow mixing area, the sewage flow rate slows down, allowing the flocculant to have more time to come into contact with suspended particles, promoting the further development of flocculation effect.
Sedimentation: After slow mixing, the sewage flows into a sedimentation tank or sedimentation tank. Due to the action of flocculants, suspended particles aggregate into larger particles and gradually settle to the bottom to form sludge. Clear water flows out from above and enters the next processing step.
Filtration: After sedimentation, the sewage may also contain a portion of suspended particles, which can be removed by filtration to remove residual solid particles. Commonly used filtration equipment includes sand filters, filter cloths, etc., which can further improve the clarity of wastewater.
It should be noted that the type and dosage of flocculants should be determined based on the specific sewage properties and treatment requirements. Different types of wastewater may require the use of different flocculants and require testing and adjustment to obtain the best flocculation effect. In addition, excessive dosage of flocculant may lead to residual flocculant and affect the subsequent treatment process. Therefore, the recommended dosage should be controlled.