Ferrous sulphate heptahydrate in hardness processing of drinking water

It’s a good method to use lime and ferrous sulfate heptahydrate as coagulant to reduce the hardness of drinking water. The process is not only easy to control the dosage, but also have effective coagulation.

To get the best treatment effect, control the water PH value at 9.5 to 10.5. In the processing pool, the concentration of lime emulsion is for 2.5%, ferrous sulphate is for 15%. When adding, please pay attention to the throwing spots and the frequency of the two coagulants as to ensure the coagulating agent mixed fast evenly and efficiently. Generally, two medicament must be continuously throw at the same time and five hours a time. If ferrous sulphate and lime stop adding, PH would drop. Then the treating effect is not good.

As for dosing quantity, it needn’t to calculate how much dosage for the pool. To keep the same concentration, the simple way is only to add the amount according to the changes of PH value and the water color. When water goes out without obvious green, the adding amount for ferrous sulphate is just OK. In contrast, the amount of lime is less strict.

In addition, the storage of ferrous sulfate heptahydrate also needs more attention. Once ferrous sulphate turns yellow, its effectiveness namely failed. And it becomes alkali type ferric sulfate that doesn’t have the coagulation effect. So, ferrous sulphate must be packaged with plastic inner bag.