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Russian Filter Press Application in Metal Grinding Wastewater Treatment
Metal grinding wastewater refers to the wastewater generated during the metal processing process, especially during grinding operations such as grinding, polishing, and cutting. Filter presses are widely used in the treatment of metal-grinding wastewater. Their main purpose is to separate solid particles and liquids in the wastewater, thereby reducing pollutants in the wastewater and allowing water resources to be recycled. The following will introduce the application of filter presses in the treatment of metal-grinding wastewater.
Why Treat Hardware Grinding Wastewater?
The wastewater generated by the grinding or cutting process in the hardware factory workshop contains a large number of fine particles. The dielectric film, stabilizer, buffer polishing, and oxidant contained in the wastewater often strengthen the mutual repulsion between such fine particles, making these fine particles highly stable and dispersed and not easy to settle, which can easily cause the turbidity of the wastewater pool to be too high. If it is not properly treated and discharged directly, it will cause a considerable degree of pollution to the environment.
Wastewater Treatment Scheme
First, the production wastewater is screened to remove coarse impurities and enters the regulating tank. It is then lifted by a lifting pump to the coagulation flotation tank for pretreatment, such as removal of suspended solids. The effluent flows by gravity into the anaerobic tank, where the organic matter in the water is hydrolyzed and acidified, which can improve the biochemical properties of the wastewater.
After that, the wastewater enters the aerobic tank for aerobic treatment. The aerobic tank is equipped with a composite filler. The cultivated aerobic bacteria live on the filler in an attached form. Under the continuous oxygenation and flushing of the aeration system, the organic matter in the sewage is used as nutrients for metabolism. The detached membrane blocks form sludge and enter the dosing sedimentation tank. The effluent of the dosing sedimentation tank is discharged through the discharge tank in compliance with the standards.
Finally, part of the sludge in the sedimentation tank is returned, and part of it enters the sludge tank with the coagulation sedimentation sediment, which is dehydrated by the filter press and transported to the sanitation department for treatment after forming dry residue.
Filter Press Application Process
- Pretreatment stage
Before the wastewater enters the filter press, it is usually pretreated. By adding chemical agents (such as PAM and PAC), the charge balance between particles is destroyed, causing these fine particles to condense into larger flocs, which is convenient for the filter press to separate solids and liquids. - Feed and filter
After pretreatment, the metal-grinding wastewater is transported to the filter press. The solid particles gradually form a filter cake between the filter plate and the filter cloth, while the liquid part is discharged through the filter cloth. The material and pore size of the filter cloth need to be selected according to the particle size of the metal-grinding wastewater to ensure the best filtering effect. - Unloading filter cake
As the filtration is completed, the filter cake gradually forms on the surface of the filter cloth and is compacted into blocks. The filter cake contains a large amount of metal particles, grinding residues, and some chemical additives. For the treatment of hardware grinding wastewater, the metal content in the filter cake may be high, and recycling can be considered. - Timely cleaning
During the treatment of hardware grinding wastewater, since the wastewater contains more fine metal particles and chemicals, it is particularly important to regularly clean the filter cloth and filter plate of the filter press to prevent clogging and affect the filtration efficiency.
Conclusion
The filter press plays a critical role in the treatment of hardware grinding wastewater. It can efficiently remove fine metal particles and suspended solids in wastewater and reduce environmental pollution. Through pretreatment, solid-liquid separation, and other steps, the filter press can fully purify wastewater and achieve resource recovery and water recycling.
