company news about Application of polyaluminum chloride（PAC） in papermaking wastewater treatment process

In the global paper industry generating over millions-tons of wastewater annually, efficient coagulation-flocculation processes have become critical for sustainable production. As a milestone of modern water treatment systems, Polyaluminum Chloride (PAC) demonstrates unparalleled advantages in removing colloidal contaminants and reducing chemical oxygen demand (COD). Today we explores PAC's mechanism in papermaking wastewater remediation and its technical superiority over traditional coagulants.

After dosing coagulants and flocculants to wastewater, an electrical neutralization reaction occurs and compresses the double layer on the surface of the particles, causing the colloids to lose their stable state. Then, through adsorption bridging, sweeping, and net capture, pollutant particles in the water form larger flocs, which are separated from the water by precipitation or air flotation, achieving the goal of purifying the water body.

The main methods for advanced wastewater treatment include flocculation, oxidation, adsorption, and filtration. After extensive engineering practice, most deep treatment processes use flocculation and oxidation methods. The coagulants used in the flocculation method mainly include polyaluminum chloride（PAC）, polymeric ferric sulfate, polymeric aluminum iron, FeCl3, Fe2 (SO4) 3, Al2 (SO4) 3, and AlCl3. The coagulants used mainly include high relative molecular weight polyacrylamide (PAM). Flocculation causes colloidal substances and large organic molecules in water to form flocs, which are then carried away by solid-liquid separation devices such as precipitation, air flotation, and filtration to remove solid substances from the water. At present, the most commonly used coagulants are polyaluminum chloride（PAC） and Al2 (SO4) 3, and the most commonly used coagulant aid is cationic polyacrylamide (CPAM). Compared with Al2 (SO4) 3, polyaluminum chloride（PAC）is easy to dissolve, has low requirements for raw water temperature, simple operation, small dosage, less foam, generates large alum flowers, has high efficiency, fast sedimentation, is widely applicable to pH (5.0~9.0, but 6.0~8.0 has better effect), is less corrosive, and has stable CODCr removal rate; Meanwhile, adopting polyaluminum chloride（PAC）treatment results in less increase in salt content in the water, which is beneficial for ion exchange and high-purity water production.

As a leading manufacturer of high-quality polyaluminum chloride (PAC), Lanyao Water Treatment Co., Ltd. specializes in producing advanced coagulant solutions tailored for wastewater treatment needs. With stringent quality control and a focus on sustainable innovation, we provide reliable, cost-effective coagulants that empower industries worldwide to achieve optimal water purification results. Partner with us to enhance your treatment processes with precision-formulated PAC solutions.