As a supplier of Drinking Grade Polyaluminium Chloride (PAC), I’m often asked about the proper steps for using this essential water treatment chemical. In this blog post, I’ll walk you through the detailed process of using Drinking Grade PAC in water treatment, from understanding its properties to the actual application steps. Drinking Grade Polyaluminium Chloride
Understanding Drinking Grade Polyaluminium Chloride
Drinking Grade PAC is a high – quality coagulant widely used in water treatment for potable water. It has several advantages, including its ability to effectively remove suspended solids, colloidal substances, and some heavy metals from water. The chemical formula of PAC is [Al₂(OH)ₙCl₆₋ₙ]ₘ, where n = 1 – 5 and m ≤ 10. Its polymerization degree and the ratio of hydroxyl to aluminum determine its coagulation performance.
Step 1: Water Quality Analysis
Before using Drinking Grade PAC, it is crucial to conduct a comprehensive water quality analysis. This analysis should cover parameters such as turbidity, pH value, alkalinity, and the presence of various contaminants. Turbidity indicates the amount of suspended solids in the water, which is a key factor in determining the dosage of PAC. The pH value affects the coagulation process; generally, the optimal pH range for PAC coagulation is between 6 – 8. Alkalinity is also important as it provides the necessary buffering capacity during the coagulation process.
You can use standard laboratory equipment to perform these analyses. For example, a turbidimeter can measure the turbidity of water, a pH meter can determine the pH value, and titration methods can be used to measure alkalinity. By understanding the water quality, you can accurately determine the appropriate dosage of PAC and optimize the treatment process.
Step 2: Preparation of PAC Solution
Once you have analyzed the water quality, the next step is to prepare the PAC solution. Drinking Grade PAC is usually available in solid or liquid form. If you are using solid PAC, you need to dissolve it in water to form a solution.
The general ratio for preparing the PAC solution is to add 10 – 20% (by weight) of solid PAC to water. For example, if you want to prepare 100 kg of a 15% PAC solution, you would add 15 kg of solid PAC to 85 kg of water. It is important to stir the mixture thoroughly to ensure complete dissolution. You can use a mechanical stirrer or an agitator to achieve this.
When using liquid PAC, you can directly use it after dilution. The dilution ratio depends on the specific concentration of the liquid PAC and the water quality. Usually, a dilution ratio of 1:10 – 1:50 is common.
Step 3: Dosage Determination
Determining the correct dosage of PAC is critical for effective water treatment. The dosage is mainly determined by the water quality parameters obtained from the analysis in Step 1.
There are several methods to determine the dosage. One common method is the jar test. In a jar test, you take several samples of the water to be treated and add different dosages of the PAC solution to each sample. Then, you stir the samples at a certain speed for a specific time and let them settle. After settling, you measure the turbidity and other relevant parameters of each sample. The dosage that results in the lowest turbidity and the best water quality is the optimal dosage.
In general, the dosage of Drinking Grade PAC ranges from 5 – 50 mg/L, but it can vary depending on the water source and the level of contamination. For example, water with high turbidity may require a higher dosage, while relatively clean water may need a lower dosage.
Step 4: Coagulation Process
After determining the dosage, it’s time to start the coagulation process. The PAC solution is added to the water to be treated. It is important to add the PAC solution evenly and quickly to ensure good mixing.
When PAC is added to water, it hydrolyzes and forms various aluminum hydroxide polymers. These polymers can neutralize the negative charges on the surface of suspended particles and colloids, causing them to aggregate and form larger flocs. This process is called coagulation.
The mixing speed and time during the coagulation process are also important. In the initial stage, a high – speed mixing (about 100 – 200 rpm) for 1 – 2 minutes is usually required to ensure rapid dispersion of the PAC in the water. Then, a slow – speed mixing (about 20 – 50 rpm) for 10 – 20 minutes is needed to allow the flocs to grow.
Step 5: Flocculation and Sedimentation
After the coagulation process, the water enters the flocculation and sedimentation stage. Flocculation is the process of further growing the small flocs formed during coagulation into larger and heavier flocs. This can be achieved by gentle stirring or using flocculants to assist the process.
Once the flocs have grown to a sufficient size, they will settle to the bottom of the sedimentation tank under the action of gravity. The sedimentation time usually ranges from 1 – 2 hours, depending on the size and density of the flocs. During this time, the clear water above the sediment can be gradually removed.
Step 6: Filtration
After sedimentation, the water still contains some small particles and residual flocs. Filtration is used to further remove these impurities. Common filtration methods include sand filtration, activated carbon filtration, and membrane filtration.
Sand filtration is a simple and widely used method. The water passes through a layer of sand, and the small particles are trapped in the sand layer. Activated carbon filtration can remove organic substances and some odors from the water. Membrane filtration, such as microfiltration, ultrafiltration, and reverse osmosis, can provide a higher level of purification, but it is more expensive.
Step 7: Disinfection
The final step in water treatment is disinfection. Even after coagulation, flocculation, sedimentation, and filtration, the water may still contain some microorganisms. Disinfection is used to kill these microorganisms and ensure the safety of the drinking water.
Common disinfection methods include chlorination, ozonation, and ultraviolet (UV) disinfection. Chlorination is the most widely used method. Chlorine can react with water to form hypochlorous acid and hypochlorite ions, which have strong oxidizing properties and can kill bacteria, viruses, and other microorganisms.
Conclusion
Using Drinking Grade Polyaluminium Chloride in water treatment is a multi – step process that requires careful analysis, proper preparation, and precise operation. By following these steps, you can effectively remove contaminants from water and ensure the safety and quality of drinking water.
Water Treatment Equipment If you are interested in purchasing Drinking Grade Polyaluminium Chloride for your water treatment needs, please feel free to contact us for more information and to start a procurement negotiation. We are committed to providing high – quality products and professional technical support.
References
- Letterman, R. D. (2005). Water Quality and Treatment: A Handbook of Community Water Supplies. McGraw – Hill.
- AWWA (American Water Works Association). (2017). Water Treatment Plant Design. McGraw – Hill.
- Gregory, J., & Barany, K. (2005). Coagulation and Flocculation in Water and Wastewater Treatment. IWA Publishing.
Shandong Ecolink Technology Co., Ltd.
Shandong Ecolink Technology Co., Ltd. is one of the most reliable drinking grade polyaluminium chloride manufacturers and suppliers in China. We warmly welcome you to wholesale bulk high quality drinking grade polyaluminium chloride from our factory. If you have any enquiry about cooperation, please feel free to email us.
Address: No. 8, Xiaying Chemical Industry Park, Aobu Road, Xiaying Town, Changyi City, Weifang City, Shandong Province，China
E-mail: sale02@ecolink-environment.com
WebSite: https://www.ecolink-environment.com/
