Representative polymer polyacrylamide are: non-ionic polyacrylamide (ABBREVIATED NPAM, molecular weight 8-15 million), anionic polyacrylamide (abbreviated APAM, molecular weight 8-20 million), cationic polyacrylamide (abbreviated CPAM, molecular weight 8-12 million, ionic degree 10%-80%). The amount used is generally 1 to 2 parts per million of waste water.