1. It is necessary to prepare a 3%-5% aqueous solution in advance.

2. Dissolve the powdered polyacrylamide in a stirring tank.

3. Add the prepared PAC solution to the sewage while stirring, and constantly test the pH value of the water quality.

4. When the pH value of the water reaches weak alkalinity, add polyacrylamide to dissolve, and the normal addition amount is 0.5%.