The water treatment is designed by MOOGE which is mainly used for the circulation of waste water comes from the plastic washing line. The dissolved air flotation technology in the sewage treatment plays an important role in solid-liquid separation. Mix suitable flocculants and coagulants into the waste water and stir thoroughly. Large sum of micro bubbles generated by dissolving and releasing system will adhere to solid particles which will float to the water surface, in this way we will achieve the goal of separation. The water then after filter system can be clean enough for reuse.