Study On The Treatment Of Emulsified Oil Wastewater By New Method Of Demulsification

Emulsion wastewater has the characteristic of high emissions, stable, difficult to remove and high endanger degree, which is due to orient absorption and form solid interfacial film among the emulsifier molecules in the oil-water boundary surface. Therefore, it increases the effective thickness of diffuse electric double layer, and makes the width and steepness of potential distribution enlarge, which leads to oil disperse high degree uniformity and stability in water and makes it difficult to remove. Demulsification is the key technology for separation and purify of emulsion wastewater which eliminates or weakens the emulsifier effect, destroys the adsorbed film of oil-water surface, decreases the same charge of dispersed particles. It gets the order of effective separating between Emulsion and water. With Synthetic water of 40 mg/L emulsified oil as the treatment object, demulsification conditions of flocculant and removal effect of Emulsion were studied through adding aluminum sulfate, anchor, polyaluminium chloride and polyacrylamide respectively. The results showed that pH had an effect on the four flocculants especially on the inorganic flocculant in the appropriate dosing quantity of Flocculation demulsifier. Therefore, the pH is an important factor for the flocculant demulsification. Most of emulsion wastewater are acidic or even is strongly acidic. Aeration has an air flotation effect and increases the reaction activity for emulsion wastewater. Acidification aeration is proposed in this paper as the demulsification process. At first, emulsion wastewater is treated by aeration under the pH 3 to 4, then adds appropriate flocculating agent to demulsification reaction. The last step is flotation and sedimentation by adding flotation agent (Polymeric Ferric Sulfate). It could get the effective removal efficiency of emulsion; The flocculant dosing quantity and removal efficiency are aluminum sulfate (0.6mg/L,84.2%). ferric chloride (0.6mg/L,88.9%), polymeric aluminium (0.5mg/L,92.5%) and polyacrylamide (0.6mg/L,95.5%). It is because that the surfactant could generate water-fast fatty acid or fatty alcohol with acid, breaks the stability of emulsion system and gets the order of demulsification under the pH 3 to 4. Acidification aeration process has the characteristic of the process and equipment simpleness, treatment effect relatively stable and the higher removal efficiency for emulsion. It presents a new demulsification process for the emulsion wastewater.