A biochemical pretreatment method for gallic acid production wastewater

A technology for gallic acid and wastewater production, applied in biological water/sewage treatment, natural water treatment, chemical instruments and methods, etc., can solve the problem of low COD removal rate, and achieve the effect of reducing COD, reducing inhibition, and reducing dosage

Active Publication Date: 2021-11-26
NANJING UNIV +1
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Problems solved by technology

[0007] Aiming at the problem that the existing gallic acid production wastewater has a low removal rate of COD in the wastewater while the gallic acid is recycled as a resource, the present invention provides a biochemical pretreatment method for the gallic acid production wastewater. Reasonably configure the treatment process of substances, and adopt the strategy of adding calcium ions step by step. While realizing the recovery and resource utilization of gallic acid, it can effectively reduce the concentration of sulfate ions in wastewater and improve the COD removal rate of gallic acid production wastewater.

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  • A biochemical pretreatment method for gallic acid production wastewater
  • A biochemical pretreatment method for gallic acid production wastewater
  • A biochemical pretreatment method for gallic acid production wastewater

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Embodiment 1

[0043] A biochemical pretreatment method for gallic acid production wastewater, comprising the following steps: the process flow is as follows figure 1As shown, including sequentially connected resin adsorption system, water distribution tank, neutralization tank, plate and frame filter, hydrolysis acidification tank, ECSB reactor, anoxic tank, aerobic tank and secondary sedimentation tank, coagulation sedimentation tank, clear water tank .

[0044] First, the resin adsorption system is used to recycle waste water. The crude gallic acid mother liquor is pretreated by precipitation and filtered, and then enters the resin adsorption system to recover the gallic acid in the mother liquor, and at the same time greatly reduce the COD of the wastewater, and the effluent enters the high-concentration regulating pool. After resin adsorption and separation treatment, more than 85% of the gallic acid in the wastewater can be recycled, and at the same time reduce more than 30% of the CO...

Embodiment 2

[0059] The process route in Example 1 is used to treat gallic acid production wastewater, wherein the resin adopts D201, and its adsorption rate for gallic acid in the thick mother liquor wastewater of gallic acid is 99%; the gallic acid in the resin treatment effluent wastewater is about 80mg / L , the mass concentration of sulfate radicals is 600mg / L, as shown in Table 1. First, adjust the pH of the wastewater to 6.5-7.5 with 30% sodium hydroxide solution, and then add calcium chloride solution to the neutralization tank twice. And in the pool, calculate the concentration of the substance that adds calcium ions for the first time according to the following empirical formula:

[0060] no A =k 1 no 1

[0061] Among them, n A is the mass concentration of the calcium ion added for the first time, n 1 is the amount concentration of sulfate radical in wastewater, k 1 is the empirical coefficient, the empirical coefficient k 1 is 0.2.

[0062] From the above, it can be seen t...

Embodiment 3

[0100] In this embodiment, calcium ions are prepared from calcium hydroxide solution prepared from refined lime to increase the effective content of calcium oxide, reduce impurities and reduce the blockage of pipelines and water pumps, and reduce sludge production at the same time.

[0101] The process route in the embodiment 1 is adopted to process the gallic acid production waste water, the water quality of the waste water is basically the same as in the embodiment 2, wherein the resin adopts D201, and its adsorption rate for gallic acid in the thick mother liquor waste water of gallic acid is 99%; first use 15% sodium hydroxide solution to adjust the pH of the wastewater to 4-5, and then add calcium hydroxide solution to the neutralization tank twice, and calculate the concentration of the first calcium ion in the neutralization tank according to the following empirical formula for:

[0102] no A =k 1 no 1

[0103] Among them, n A is the mass concentration of the calci...

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Abstract

The invention discloses a biochemical pretreatment method for gallic acid production wastewater, which belongs to the technical field of environmental protection. It comprises the following steps: (1) adopting resin to absorb gallic acid in waste water; (2) adding sodium hydroxide to the effluent water of step (1) until the pH of the solution is 4-7.5, and then adding the solution containing calcium ions several times , filter; (3) step (2) water into the biochemical treatment step. Among them, an insufficient amount of calcium ions is added for the first time, and a sufficient amount of calcium ions is added for the second time. The precipitation treatment process after the resin greatly reduces the amount of calcium ions, and also reduces the impact of residual calcium ions on the biochemical treatment process. Inhibition can not only achieve the purpose of removing residual gallic acid and sulfate radicals, but also achieve the purpose of further reducing COD.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and more specifically relates to a biochemical pretreatment method for gallic acid production wastewater. Background technique [0002] The method for industrial production of gallic acid is to firstly hydrolyze gallic tannic acid to digallate with gallnut as raw material, and then use sulfuric acid as a hydrolysis catalyst to obtain gallic acid by pressurized hydrolysis. The production and refining process of gallic acid will produce a large amount of waste water. The waste water mainly contains gallic acid, tannic acid, inorganic salts, sulfuric acid and other components. The content of gallic acid may reach about 2%, and although the toxicity of gallic acid to the human body is extremely small , but in the process of chlorine disinfection of drinking water, halogenated hydrocarbons can be produced, which have teratogenic, carcinogenic and mutagenic effects on the human body, a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/14C02F11/121C02F101/30C02F103/36
CPCC02F1/28C02F1/52C02F3/30C02F3/34C02F9/00C02F11/121C02F2101/30C02F2103/36
Inventor 张炜铭朱兆坚吕路周兵王宁林原潘丙才
Owner NANJING UNIV
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