High acid crude oil electric desalting wastewater treatment method

Abstract

The present invention discloses a high acid crude oil electric desalting wastewater treatment method, which comprises that high acid crude oil electric desalting wastewater is sequentially subjected to an oil and suspended solid removing treatment, a sequencing batch reactor activated sludge treatment (SBR), a flocculation treatment, a Fenton oxidation treatment and a membrane bioreactor (MBR) treatment, wherein SBR is mainly provided for removing BOD and ammonia nitrogen, the flocculation treatment and the Fenton oxidation treatment are mainly provided for treating naphthenic acid and other organic matters difficultly degraded by SBR, and MBR is provided for deep treatment of residual dissolved organic matters and suspended solids after the Fenton oxidation treatment. According to the present invention, COD in the treated effluent is less than or equal to 40 mg / L, ammonia nitrogen in the treated effluent is less than or equal to 2 mg / L, petroleum in the treated effluent is less than or equal to 2 mg / L, and turbidity is less than 1 NTU, such that the stringent local discharging standard can be met, and the effluent can be used as influent for reverse osmosis constant depth reuse treatments. The method is suitable for standard discharging treatments of electric desalting wastewater from high acid crude oil processing or polymer flooding oil field wastewater and various naphthenic acid-containing wastewater.

Description

Technical field [0001] The invention belongs to the technical field of wastewater treatment, and specifically relates to a method for treating high-acid crude oil electric desalination wastewater. Background technique [0002] At present, the electric desalination wastewater of oil refineries is generally treated by the traditional oil separation-flotation-biochemical-clarification or sand filtration process. When this process is used to treat high-acid crude oil electric desalination wastewater, the COD of the effluent is usually higher than 200 mg / L, and some are higher. The A / O treatment effluent of the electric desalination wastewater of acid crude oil is even as high as 700-800 mg / L, which far exceeds the national wastewater discharge standard (COD≤100 mg / L). As the processing volume of low-quality and high-acid crude oil in my country increases year by year, and some regions implement stricter local wastewater discharge standards (COD≤60 mg / L), the contradiction in the disc...

AI Technical Summary

Problems solved by technology

US5976366 uses a two-stage oil-water separation-gas stripping-activated carbon adsorption-flocculation process to treat electric desalination wastewater. The process is complicated and the operating cost is high, and the treatment effect of high-acid crude oil electric desalination wastewater has not been seen.

CN1078567C extracts naphthenic acid wastewater with a mixed solvent of tertiary amine and diesel oil, the extract is back-extracted with sodium hydroxide lye, and the extractant is separated and reused. The reagent consumption of this method is large, the cost is high, and the extraction process is easy to produce Emulsification, high COD of treated effluent

CN1209302C provides a method for treating naphthenic acid wastewater by flocculation-electroheterogeneous catalytic oxidation. The process of this method is relatively complicated, the energy consumption is high, and the treatment effect of naphthenic acid is limited

[0006] Although there are many kinds of sewage treatment units in the prior art, and the combined methods of different treatment units are used to treat sewage from different sources, when it is used to treat high-acid crude oil electric desalination wastewater, due to the special properties of wastewater and the mutual constraints between different units, Processing effect is still very limited