Principles and methods of wastewater treatment generated by aluminum profile surface treatment

Wastewater generated by aluminum profile surface treatment is mainly acid-base wastewater, containing a small amount of harmful anions and cations such as Ni2+, Sn2+, and F-. The treatment method is acid-base neutralization. Wastewater is generally acidic and must be neutralized with alkali to adjust the pH value to about 7-8.5. At the same time, during the neutralization process, cations such as Al3+, Ni2+, Sn2+, and Cr3+ all form hydroxide precipitation. The neutralized and precipitated wastewater is pumped into the coagulation tank with a pump, and the dissolved polyamide flocculant is pumped into the wastewater with a quantitative pump to coagulate with the wastewater. After coagulation, the wastewater enters the sedimentation tank. The sedimentation methods include inclined plate sedimentation method, air flotation method, centrifugal sedimentation method, etc. The author believes that the centrifugal sedimentation method is more stable. After sedimentation, the clear liquid overflows from the upper overflow port and enters the discharge pool or reprocessing water storage tank.

 After the above treatment, the wastewater can meet the discharge standards. If the wastewater is to be reused, the wastewater can be treated by coarse filtration and then enter the RO device to remove excess anions, cations and organic matter. The pH value of the water may be low at this time, and it can be adjusted by the anion and cation exchange device to meet the reuse standards. The sludge produced by precipitation is regularly discharged into the sludge pool, and after being treated by a plate cake press or a belt dehydrator, it becomes industrial waste residue and is sent to the industrial waste residue treatment plant.