Presently the polymer flooding systems used for tertiary oil recovery in  Daqing. Shengli and Liaohe oil fields are polymer drive. Binary combination drive. Ternary combination drive. Low concentration cross-linked polymer drive. Colloidal dispersion gel (CDG)drive and surfactant drive etc. The most polymers used in measures of profile control and flooding are hydrolysis polyacrylamide (HPAM). Since the molecular of HPAM contains both coo and CONH, so it is not only an anionic polymer but also a hydrophilic surfactant. Producing fluid of the producers corresponding to the polymer drive and profile control injectors exists polymer alkali and surfactant which make the oily wast water containing polymer a more complex oil ﹠water system, produced fluid viscosity increased, crude oil seriously emulsified. It is very hard to separate water from oil by natural sedimentation and the produced fluid is even harder to be treated compared to the conventional produced fluid. As for the oil dehydration, dehydration rate decreases waste water quality decreases some impurities occur in water and oil﹠water interface is not clear and what′s more, there are intermediate layers in between, which cause the electric dehydration operation does′nt work properly. As for the waste water treatment after dehydration, produced fluid viscosity increases, oil﹠water separation is slow and waster water treatment ability decreases. With additional forming of oil﹠water emulsion, it wakes oil cut in wastewater over exceeded, and the coexistence of  HPAM and cationic flocculant and coagulant affects the flocculation and sedimentary results, and causes wastewater oil cut and suspended solids content seriously over exceeded. Therefore, the existence of the polymer has seriously affected the result of oil dehydration and oily wastewater treatment.

Through many years researches and field tests, our corporation has successfully developed a complete set of polymer-bearing wastewater treatment technology and equipments. So far, three polymer-bearing wastewater treatment stations with treating abilities of 6000m ³/d, 16000 m ³/d  and 20000 m ³/d respectively have been built in shengli oilfield, and have gained excellent results. Take polymer-bearing wastewater treatment station of  Gu №6 CPU as an example; Its designed capacity is 20000 m ³/d, designed water quality :oil cut in inlet water is ≤7000㎎/l; suspended solids ≤500㎎/l; polymer≤150㎎/l. After treatment oil cut in water is ≤50㎎/l; suspended solids ≤50㎎/l; chemical dosage added :10㎎/l; PAC 300㎎/l.