Study On Treating Oilfiled Wastewtaer With Suface Modified Magnetism

Oilfield wastewater mainly comes from oil extraction wastewater after degassing and dewatering, salt wash and well-flushing liquor. It has the characteristics of high temperature, high TSD, high oil content, high pH, massive scaling ion and bacteria, also low dissolved oxygen and certain amount's emulsion breaker, and high pollution intensity. Traditional technology no longer meets the requirement of outlet water quality and the wastewater integration discharge standard with the development of production technology. Therefore, it's imperative to seek economical, reasonable and feasible technology and new equipment treating oilfield wastewater.In view of Jiangsu oilfield wastewater, the paper studied the oil removing potency of modified magnetic material. After carrying iron-oxide compounded surface modification to the powdery Fe₃O₄ by sedimentation, and carrying on silylation process, it can strengthen the adsorption and compatible performance between Fe₃O₄ magnetic powder and the oil dripping adsorption. And the resin acceptor that adsorbs on the surface of Fe₃O₄ can prevent agglutination of Fe₃O₄, slow down the settling rate and be propitious to remove oil from the oilfield wastewater. It has preferable effect on removing emulsified oil and the slight impurity from wastewater which uses Fe₃O₄ magnetic pellet as filtration material after modification by the oleic acid. The paper discussed the oil removing potency of electro-flotation & surface modified magnetism filtration, and proposed feasible processing technology and suitable operational factors, through the orthogonal and flowing wastewater experiment.According to the experimentations, it was noted that when oil content is 118.6 mg/L, COD is 627.3 mg/L, water flow quantity is 0.15～0.18 m3/h, water power resident time is 3.96～3.5 min, and currernt intensity is 0.5 A～1 A, the equal oil content of effluent can reduce to 25.8 mg/L, the oil removing rate reaches 78.2%, COD can reduce to 191.1 mg/L, and COD removing rate reaches 69.5% by setting of experimental system of electro-flotation & surface modified magnetism filtration. It is feasible and stable to treat oilfield wastewater using this technology which proposed a new technology of oilfield wastewater treatment and provided a reference to further study of oilfield wastewater.Fe₃O₄ magnetic pellet had excellent oil removal potency after surface modification. On the one hand, it has more surface area compared to some natural oxide compounds. On the other hand, it had a bigger adsorption capacity to the oil because of its surface character. And its surface adsorption is not a general physisorption, but a saturated adsorption process. The quantity of oil adsorption mainly based on collision probability between the magnetic pellet and the oil dripping. This material had rich origin, low price, and had a characteristic of putting the waste against the waste in the oilfield wastewater treatment, also no need to increase the recycling setting.