【正文】 y suspended solids, so produced water also contains a lot of organic matter, for the growth of microorganisms to provide the necessary environment. Due to differences in reservoir geology, mining technology and other production conditions, oilfield wastewater contained there are some differences in the type and nature of the pollutants, but in general oilfield wastewater containing a variety of crude organic ingredients and various chemical agents, chemical oxygen demand high, is a plex nature, special industrial waste contains more impuritiesII. Features oilfield wastewater(1) impurities in the water divided into insoluble inorganic, bacteria and organic matter content is generally 100500mg / l, diameter range is usually between 1100um, small particles, settling slowly in the natural force of gravity。 Table 21 for mon nonsoluble (or slightly soluble) in the sewage substancesTable 21 inorganic and organic matter suspended in waterInsoluble inorganicOrganicsCalcium carbonate, calcium sulfate Clay sand iron sulfide, iron and magnesium sulfate, barium and silica * etc.Yeast bacteria protozoa diatom algae rot organisms polymers tannins oilSilica for suspended solids in water can also be dissolved in water(2) high oil content. Most of the oil content of the oil field wastewater is generally 1000 mg / l or more, some even up to 10000 mg / l, of which 90% (1) high levels of suspended solids. Oilfield wastewater suspended solids include silt, a variety of corrosion products and dirt into about quality of 10 100 um dispersed oil slicks and more than 100um, with good settling properties, the remaining 10 percent, pared with about 1 10 310um emulsified oil。 (3) a high organic content. Various chemicals in the mining and primary processing of crude oil added during such viscosity, corrosion, scale, emulsion breaking, coagulation, sterilization, etc., forming the higher oilfield wastewater CO D content, these properties plex organic matter must be well removed otherwise would cause adverse environmental effects, oilfield wastewater treatment discharge standards focus。 (4) high salinity. Salinity oilfield wastewater is generally 1000mg / l or more, even up to a maximum 10 5mg / l, the high salinity of the piping and equipment have a strong corrosive effect, and cause some difficulties for the biological treatment of sewage。 (5) microbiological content. Oilfield wastewater contains large amounts of iron bacteria, saprophytes, SRB and other types of microorganisms that use mineral water in the breeding, the formation of large scale quality, corrosion protection systems for water pose a great threat.Oilfield Sewage addition to these features, it also has the characteristics of large changes in water quality and quantity. This topic Liaohe Oilfield Oilfield Sewage Huan quadruple as experimental subjects for sewage PH, suspended solids, oil content, COD and BOD content of the sample analysis. Experimental results are shown in Table .Table 22 and Water Quality IndexWater Quality IndexWater Quality4Quality water, suitable for most formations4~12In the quality of water12~20Poor water quality, can clog sandstone20Poor water quality, the need for further treatment, perhaps for acidification or fracturing the formation of dolomite Crude oil state in the presence of sewageOilfield wastewater containing oil generally floating oil, dispersed oil, emulsified oil, dissolved oil and oil solid five forms:(1) floating oil: the continuous phase floating on the water, to form a film or oil. This oil droplet diameter is large,Generally greater than 100μm。(2) dispersing oil: In dispersed fine oil droplets suspended in water, instability, still shorter than a certain period of time can gatherLard beads and float to the surface will bee a floating oil droplet diameter 10100μm。(3) emulsified oil: because the water leaving the oil containing a surfactant and water to form a stable emulsion, droplet diameterGenerally less than 10μm, most of 。(4) dissolving the oil: a stable molecular state dispersed in water forming a homogeneous system, straight oil dropletsDiameter smaller than the emulsified oil, sometimes as small as a few nanometers。(5) Oil solids: oil in water oil adhesion on the surface of the suspended solids solid. universal mon oilfield wastewaterDue to the underlying structure and production means diverse influences, especially heavy oil recovery, EOR impact, oilfield wastewater quality varies, but there are monalities. Shengli Oilfield by the end of 2004 under the main sewage treatment plant for water quality survey, the main criteria for floating large, specifically: water oil content / L, an average of / L, suspended solids content of 15224mg / L average 77mg / L.According to the Shengli Oilfield, and our other major oilfield wastewater situation, oilfield wastewater contain a large number of oil, soluble organic matter, solids, inorganic ions, microorganisms, making wastewater COD, oil, volatile phenol, sulfur pounds, suspended solids such as higher concentrations inconsistent with water quality standard, it is difficult to reach GB897896 integrated Wastewater Discharge Standard requirement, oilfield wastewater main features are summarized below:(1) Crude oil content: Most of oily wastewater oil content in 50mg / L or more, of which about 90% of the dispersed oil 10100μm larger than 100μm and floating oil, the remaining 10 percent, pared with about 1 103 10μm of emulsified oil.Table 22 Common meter scale oil and gas fieldsConstituentTypical solubility /()Calcium sulfate1500~6000Strontium sulfate300~600Calcium sulfate10~80Barium sulfate3~60(2) high levels of suspended solids: small particle size, oilfield wastewater suspended solid particles in the diameter range 1100μm, including sediment, corr