There has poly aluminium chloride for drinking water on the market. In China, poly aluminium chloride for drinking water manufacturers are required to have the Sanitary License for Water-related Products issued by the Ministry of Health. Moreover, the polyaluminum chloride for drinking water products needs to meet the requirements of the “GB 15892-2020” standard. In other uses, polyaluminum chlorides are not required to meet these requirements.
          Polyaluminum chloride for drinking water has restrictions on raw materials. The main raw materials are synthetic hydrochloric acid and aluminum hydroxide, so the cost of raw materials and the price are also high. On the other hand, for safety, the additives is limited, so under the same conditions, the effect of poly aluminium chloride for drinking water is slightly worse than poly aluminum chloride for industrial. Safe drinking water is important, it is forbidden to replace the poly aluminium chloride for drinking water with poly aluminium chloride for industrial.
Polyaluminum chloride for drinking water

The process of using poly aluminum chloride for drinking water

Dissolve poly aluminum chloride and tap water in a weight ratio of 1:3 to make it transparent. When the COD concentration of the raw water is 100~500mg/L, the dosage is 3~6mg/I. That is, the dosage per thousand tons of water is 3-6kg of poly aluminum chloride for drinking water. In practical application, when the turbidity of the raw water is high, the dosage is appropriately increased, and when the turbidity is low, the dosage can be reduced. Conditions permitting, it is recommended to conduct experiments and comparisons according to water quality conditions to select the best usage.

Technical indicators of poly aluminium chloride for drinking water

Reference to national standards “GB 15892-2020 Poly aluminum Chloride for Drinking Water” standard
Specifications GB15892-2020
Item
Index
Al2O3,%
≥
29.0
Basicity,%
45-90
Insoluble substance,%
≤
0.1
PH(1% water solution)
3.5-5.0
As,%
≤
0.00010
Cr,%
≤
0.00050
Hg,%
≤
0.00001
Pb,%
≤
0.00050
Cd,%
≤
0.00010
Fe,%
≤
0.2
Note: The mass fractions of Insoluble substances, As, Pb, Cd, Hg, Fe, and Cr are calculated based on that of Al2O3 as 10.0%. When the concentration of Al2O3 is over 10.0% the standard need to be calculated as a multiple of 10.0%.

Coagulation process of poly aluminum chloride for drinking water

1. Condensation stage

       Polyaluminum chloride is rapidly mixed with raw water to form flocs in a very short time. At this time, the water becomes more turbid. This process requires thorough mixing of water and poly aluminum chloride.

In the beaker experiment, it is advisable to stir rapidly (250-300 rpm) for 10-30s, not exceeding 2min.

2. Flocculation stage

The process of flocs growing and becoming larger requires proper stirring and sufficient residence time (10-15min). It can be observed that a large number of flocs gather and sink slowly, and a clear layer is formed on the surface.

In the beaker experiment, first, stir at 150rpm for about 6min, and then stir at 60rpm for about 4 min until it is in a suspended state.

      3. Settlement stage

It is a floc settling process carried out in a settling tank, which requires slow water flow. In order to improve efficiency, an inclined tube settling tank is generally used. A large number of coarse flocs are blocked by the inclined tube wall and deposited at the bottom of the tank. The upper layer of water is clarified water. While the flocs with small diameters and low densities gradually descend, they continue to collide with each other and become larger, and finally, the residual turbidity is basically unchanged.

In the beaker experiment, it is advisable to slowly stir at 20-30rpm for 5min, and then settle for 10min to measure the remaining turbidity.

4. Strengthen the filtering stage

In order to improve water quality, it is necessary to strengthen the filtration of flocs to make the water cleaner. This stage is mainly to choose the appropriate filter layer structure and filter aid.

        Polyaluminum chloride products of various specifications can sterilize, deodorize, remove fluorine, aluminum, chromium, remove oil, remove turbidity, remove heavy metal salts, remove radioactive pollutants, and have a wide range of uses in the process of purifying various water sources. The water quality of various water bodies is relatively complex. It is recommended to select the appropriate poly aluminum chloride according to the actual situation.