Method for demulsifying oil-containing emulsified wastewater by using MAP crystallization technology

Abstract

The invention discloses a method for demulsifying emulsified wastewater. The method comprises the following steps: replenishing Mg2<+>, NH4<+>, and PO43<-> ions to the wastewater, regulating a pH value, creating MAP crystallization conditions, and completing the demulsification and oil-removing process along with the generation of the crystallization. A principle of the method is that a more compact combination is formed because of the action of electrostatic attraction and chemical bonds between an MAP crystal and an emulsification ingredient, the emulsification ingredient is precipitated with the MAP crystal along with the generation and the sedimentation of the MAP, and the 'demulsification', 'oil-removing', and 'COD-removing' processes are synchronously completed. Presented in the macroscopic scale, the emulsification state of the wastewater is damaged, the clear and transparent state is presented, and a precipitate is generated. Compared with the common method for the emulsified wastewater treatment which is demulsification firstly and removes the COD secondly, two processes are completed in one step according to the MAP crystallization method, the reaction is rapid, and two processes are synergetic. The removal efficiency is good, and supernatant liquid is more limpid. According to the method, the COD, which is less than 10000 mg / L, of the emulsified wastewater is treatedto be the COD which is less than 2000 mg / L, and the load of the follow-up biochemical treatment is greatly reduced. The sedimentation velocity of sludge is rapid, the amount of the sludge is small and the dewaterability is good.

Description

technical field [0001] The invention belongs to the field of wastewater treatment and relates to the demulsification treatment of oil-containing emulsified wastewater by MAP crystallization technology. Background technique [0002] The sources of oily emulsified wastewater are very extensive, mainly in industries such as petroleum, chemical industry, machinery manufacturing, steel and food processing. For example: produced water from oil fields; separated water from oil, gas and oil products in the production process of petrochemical industry, condensed water produced by distillation, etc.; waste water produced in mechanical cutting production; in addition, there is oily waste water produced in oil factory production Wait. [0003] In the sewage discharge system, the oil in the oily emulsified wastewater will cause various effects. Grease buildup leads to a loss of hydraulic capacity in the drain (or blockage of the drain), clogging the pump inlet. In sewage treatment pla...

AI Technical Summary

Problems solved by technology

[0030] The treatment of emulsified wastewater by new demulsifiers is still not universal, and the preparation procedures of demulsifiers are generally cumbersome, and polymer demulsifiers will adversely affect the subsequent biochemical treatment units

Moreover, these patented technologies seldom consider practical issues such as investment cost, operating cost, difficulty of sludge disposal, and sludge reduction. In addition, the current state has generally raised the pollutant discharge standards of sewage treatment plants, and has stricter requirements on the quality of discharged water. Discharged sludge is required to achieve a lower water content, so it is very important to find a new method with low cost, good treatment effect, high universality for all kinds of emulsified wastewater, and less sludge volume.

[0031] In summary, none of the treatment technologies for highly emulsified, high-concentration emulsified wastewater is based on the crystallization process and products as a means of demulsification. The present invention is based on the generation of MAP crystals and its unique adsorption capacity, and Developed the demulsification technology illustrated in this patent

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