Study On The Treatment Of High Concentration Emulsifying Wastewater With Oil

High concentration emulsifying wastewater with oil is derived from many industries such as dyeing and printing industry, petrochemical industry, machine cutting, food producing and so on. It has a few characteristics such as wide varieties, large capacity of drainage, complicated component and high chemical oxygen demand (COD). It is a class of unmanageable special wastewater and harmful to eco-environment if it is discharged to environment directly. This kinds of emulsifying wastewater must be treated. It is difficult for single compound to reach efficiency of demulsifying, separation and flocculating. To resolve the problem, the Si-inorganic compound flocculant is synthesized so as to achieve the goal that high concentration emulsifying wastewater with Oil is treated efficiently.According to the actual properties and stability of emulsified oil wastewater, the Si-inorganic compound flocculant is synthesized. The average molecular weight and molecular weight distribution are determinated. Structures of flocculant is analysed, and synthesis conditions is optimized in this paper. The parameters of flocculation and congealment are ascertained. Also, the mechanism of flocculation and congealment is also discussed. From the experiment, the suitable preparation conditions of Si-inorganic compound flocculant is followed: in 100ml deionized water, sodium silicate 18.00-19.00ml, 30% sulfuric acid to adjust pH about at 4.50-5.00, the suitable amount of crosslinking agent A is 6.000g-7.000g, the temperature 37.5-42.5℃, polymerization reaction 1h, the amount of aluminum sulfate 10.0000g-12.0000g, the amount of ferric sulfate 2.8000g-3.2000g, then cultured in stabilizer B 4.5000g. The reaction temperature is increased to 70℃. reaction time 3h, aging time 23-25h. When the compound flocculant is used, the condign flocculation and congulation conditions are shown as following: the water temperature above 50-60℃, agitation intensity 50-60r/min, stirring time 15-20min, the amount of compound flocculant 9.5-10.5ml per 100ml wastewater. The wastewater is treated by the flocculant. The preferable effect is reached. The flocculation and the congealment progress are finished in one-step with the Si-inorganic compound flocculant. There are comprehensive applicabilities for many kinds of emulsification without changing pH values. In one-step treatment, wihtout adjusting pH, CODs is decreased from 9×10⁴-2.5×10⁵mg/L to 3000-6500mg/L by this compound. The removal efficiencies of COD is 95-98%. In addition, the result shows that the stability of compound flocculant is improved and the gel dose not occurr when the stabilizer B is used.There are some difficult degradation soluble organic compounds in residual organics of treated effluent. They are difficult to be oxidized. So, in secondary treatment, Fenton's reagent is used to further deal with the effluent. The optimal condition is obtained by the orthogonal experiment method. The optimal condition is showed as following: the dosing quanitiy of 30% H₂O₂ is 6.00-6.50ml, FeSO₄, 0.28-0.30g, pH 2.85-3.00 , reaction time 2h. The value of pH is adusted between 7 and 8 to deposit. The COD can be decreased to 500-1500mg/L further.When Si-inorganic compound flocculant is used to treat high concentration emulsifying wastewater with oil, the processing program is simplified. It needs less equipment. It is easy to operate and has wide applications without secondary pollution.