Wastewater pretreatment method for long-chain dibasic acid preparation process of biological fermentation method

Abstract

The invention provides a wastewater pretreatment method for a long-chain dibasic acid preparation process of a biological fermentation method. The wastewater pretreatment method comprises the steps that intermittently discharged filter-press working section wastewater in the long-chain dibasic acid preparation process is fed into a regulating reservoir to accumulate, and then is mixed with the wastewater discharged out of other working sections, and the mixture is homogenized; homogenized mixed wastewater is mixed with and react with superfluous calcium salt absorbent for phosphorus removal and / or calcium hydroxide to have phosphorus removed, and first turbid liquid is obtained; the first turbid liquid is mixed with and react with an aluminum salt treatment agent to have sulfate removed, and second turbid liquid is obtained; the second turbid liquid is mixed with a flocculant to implement settlement separation, supernate is sent to a monitoring pool, and concentrated floc is taken at the same time; the concentrated floc is subjected to mechanical dehydration treatment, solid residues are taken, and filtrate obtained after dehydration is sent to the monitoring pool; and degradable organic acid is used for regulating pH of the water body in the monitoring pool to be smaller than 9, and in other words, the water body is regulated to be alkalescent, and then the regulated water body is discharged out to a comprehensive sewage farm. With the wastewater pretreatment method for the long-chain dibasic acid preparation process of the biological fermentation method, total phosphorusand the sulfate radical load can be deeply removed, and the COD load can be greatly reduced.

Description

technical field [0001] The invention belongs to the technical field of petrochemical environmental protection, and in particular relates to a method for pretreating high-concentration waste water produced in the process of preparing long-chain dibasic acids by a biological fermentation method. Background technique [0002] Long-chain dibasic acid refers to a straight-chain dibasic acid containing more than 10 carbon atoms in the carbon chain, and its general structure is HOOC—(CH 2 )n—COOH (n=8-16). Long-chain dibasic acids are a class of fine chemical products with important and extensive industrial uses. They are used in the production of synthetic high-grade spices, high-grade nylon engineering plastics, high-temperature dielectrics, high-grade hot-melt adhesives, cold-resistant plasticizers, high-grade lubricating oils, high-grade coatings and The basic raw materials of more than a dozen categories of special high value-added products such as paints are widely used in t...

AI Technical Summary

Problems solved by technology

[0005] Among the components of dibasic acid wastewater, the total phosphorus is about 400mg / L, and it is impossible to make the total phosphorus reach the standard by directly discharging to the comprehensive sewage field

Dibasic acid wastewater carries about 4000 mg / L of sulfate radicals, which is highly toxic to anaerobic bacteria and reduces anaerobic biochemical efficiency; and with the escape of high-concentration hydrogen sulfide, it is difficult for odor pollution treatment facilities to bear, and even heavier odor pollution poses a major safety hazard Hidden danger

The COD of dibasic acid wastewater is about 7000mg / L. Although it is easy to biochemically degrade, the large amount of water (50-60 tons of wastewater / ton of dibasic acid) causes a load impact on the comprehensive sewage field. The effluent meets the comparison of 50mg / L and 60mg / L. difficulty

[0006] Although there have been researches on the treatment of long-chain dibasic acid process wastewater produced by biological fermentation, there are few reports and applications on the pretreatment of the three main indicators of total phosphorus, sulfate and COD.

Yang Jian et al [Yang Jian, Huang Weixing, Wang Shifen, Guo Changhong, Research on Treatment of Organic Wastewater from Fermentation of Thirteen Carbon Dibasic Acid [J], Environmental Pollution and Prevention, 1999, 21(1), 15-18] adopted "neutralization and precipitation + SBR" process, adding powdered lime to set the pH at 6-7, neutralizing the precipitation to remove SS as the goal; SBR technology removes more than 90% of COD, without considering the removal of total phosphorus and sulfate

Tang Guilan et al [Tang Guilan, Lan Weiguang, Yan Bin, Chen Xiaoqiang, Jiang Lin, Pilot-scale study on the transformation of dibasic acid wastewater treatment process [J], Water Treatment Technology, 2007, 33(6), 91-94] adopted " Neutralization precipitation + UASB + MBR process", can remove 97% of COD, but it does not involve the problem of excessive total phosphorus and sulfate removal

Xu Li et al. [Xu Li, Wang Mingyu, Cai Yongyi, Research on electrolytic treatment of tridecane dibasic acid organic wastewater [J], Fluid Machinery, 2007, 35(10), 1-4; Xu Li, Wang Mingyu, Wang Wei, Guo Wenpeng, Combined electrolysis and nanofiltration process to treat waste water in the production of tridecane dibasic acid [J], Chemical Engineering, 2008, 36(9), 43-46] Using electrolysis to remove 99% of COD, and then through nanofiltration Can remove 95% sulfate, high sulfate filtrate in this technology is difficult to use, and still does not involve total phosphorus removal

Yang Wenhuan et al [Yang Wenhuan, Sui Xiubin, Yu Linghong, Li Weiping, Jing Shuangyi, Zhu Hao, AMBBR-SMBBR Process Treatment of Dibasic Acid Wastewater Pilot Test Research [J], Water Treatment Technology, 2017, 43(8), 109-113 】Anaerobic moving bed biofilm reactor (AMBBR)-specific moving bed biofilm reactor (SMBBR) can remove 98% of COD, but the total phosphorus exceeds the standard

Che Shugang et al [Che Shugang, Ma Nana, Fu Yingxun, Wu Wenlei, Han Lixia, Qin Jun, Liu Wen, Bioenzymatic treatment of dibasic acid wastewater [J], Environmental Science and Technology, 2019, 32(4), 36-40 】Using biological enzyme method to make COD and ammonia nitrogen meet the "Water Quality Standard for Wastewater Discharge into Urban Sewers" (CJ343-2010), but the total phosphorus and sulfate radicals are not removed

It can be seen that most of the existing dibasic acid wastewater treatment technologies aim to remove easily degradable COD, and the removal of total phosphorus and sulfate is less considered or avoided, and there is no simultaneous removal of total phosphorus and sulfate Technology

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