Biofilter purification method for residual phase after toluene extraction of benzoic acid production waste water

Abstract

The invention relates to a biofilter purification method for benzoic acid. The method comprises the following steps: (1) residual phase waste water after toluene extraction of benzoic acid production waste water is blended with domestic sewage, and a mixed solution is formed; (2) the mixed solution after blending is sent into a novel multifunctional purifying groove, primary anaerobic acidizing hydrolysis treatment is carried out for the mixed solution firstly, then a secondary aerobic treatment is carried out, finally deposition and disinfection treatment is carried out, and the solution is discharged from the novel multifunctional purifying groove. The benzoic acid waste water which is treated after twice extraction by toluene is mixed with the domestic sewage for adjusting, and biochemical treatment is continuously carried out in the biofilter; water qualities of discharged water in different treatment conditions with different volume ratios between the benzoic acid waste water and the domestic sewage are investigated, the water qualities can meet the national town sewage discharge primary standard, the treatment effect of NH4+-N reaches the secondary standard, so that good degradation and removal effects of low concentration benzoic acid waste water through the primary anaerobic and secondary aerobic biofilter are verified.

Description

technical field [0001] The invention relates to the technical field of sewage treatment, in particular to a method for purifying a toluene raffinate phase biological filter bed of benzoic acid production wastewater. Background technique [0002] Benzoic acid, also known as benzoic acid, is the main raw material for the production of food preservative sodium benzoate. Benzoic acid is mainly produced and prepared under the catalysis of organic acid metal salts, and there are also organic compounds such as benzaldehyde and benzyl alcohol as by-products. After the high-concentration organic wastewater produced in the production process of benzoic acid is extracted with toluene, the wastewater still contains 60-100mg / L of benzoic acid and benzyl alcohol; due to the soluble properties of these organic substances, they will remain in the water, resulting in a COD concentration higher than 20000mg / L, which belongs to high-concentration organic wastewater, so it is difficult to dire...

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Problems solved by technology

Although the toluene extraction process greatly reduces the concentration of organic pollutants in the wastewater, the wastewater still cannot be discharged up to the standard, and subsequent biochemical treatment must be carried out

[0004] In the prior art, there is no relevant literature record about the biodegradation of benzoic acid wastewater after toluene extraction using a self-made bioreactor

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