CN-122010339-A - Method for advanced treatment of organic pollutants in lignite gasification biochemical wastewater by using far ultraviolet light activated oxidant

Abstract

The invention belongs to the technical field of water treatment, and particularly relates to a method for deeply treating organic pollutants in lignite gasification biochemical wastewater by using an extreme ultraviolet activating oxidant. The method comprises the steps of mixing lignite gasification biochemical wastewater with an oxidant, and carrying out photocatalytic degradation reaction on the obtained reaction liquid to obtain effluent, wherein the oxidant comprises one or more of H 2 O 2 , persulfate and periodate, and the photocatalytic degradation reaction is carried out under far ultraviolet light. The method provided by the invention can effectively degrade organic pollutants in lignite gasification biochemical wastewater, especially refractory organic pollutants, has the organic matter removal rate of more than or equal to 90%, can reach the standard and discharge, shortens the treatment period (total reaction time is 2-4 h), has strong environmental adaptability, and solves the problems of large dosage of medicament, poor pH value adaptability of wastewater, unstable treatment efficiency of low-concentration refractory organic matters, long process reaction period and high operation and maintenance cost in the traditional Fenton method.

Inventors

• JIANG LIANG
• LI FENGQIONG
• LI LIN
• YAN ZHONGLIANG
• HE JIAO
• CHEN YONGJUAN

Assignees

• 云南大学

Dates

Publication Date

20260512

Application Date

20260302

Claims (10)

1. 1. The method for deeply treating organic pollutants in lignite gasification biochemical wastewater by using far ultraviolet light activated oxidant is characterized by comprising the following steps of: mixing lignite gasification biochemical wastewater with an oxidant, and performing photocatalytic degradation reaction on the obtained reaction liquid to obtain effluent; the oxidant comprises one or more of H 2 O 2 , persulfate and periodate; the photocatalytic degradation reaction is performed under extreme ultraviolet light.
2. 2. The method according to claim 1, wherein when the chromaticity of the lignite gasification biochemical wastewater is not less than 100 times, the method further comprises mixing the lignite gasification biochemical wastewater with a flocculant, performing flocculation treatment, and mixing the obtained supernatant with an oxidant before mixing the lignite gasification biochemical wastewater with the oxidant.
3. 3. The method of claim 1, wherein the persulfate salt comprises a peroxodisulfate salt and/or a potassium peroxodisulfate complex salt.
4. 4. The method of claim 1, wherein the periodate salt comprises potassium periodate and/or sodium periodate.
5. 5. The method according to claim 2, wherein the flocculant comprises an inorganic flocculant and an organic flocculant, the inorganic flocculant is polyaluminum sulfate and/or polyaluminum chloride, and the organic flocculant is polyacrylamide and/or cationic polyacrylamide.
6. 6. The method of claim 1, wherein the extreme ultraviolet light has a wavelength of 185-365 nm.
7. 7. The method of claim 1, wherein the photocatalytic degradation reaction time is 60-240 min.
8. 8. The method according to claim 1 or 3, wherein the concentration of persulfate in the reaction solution is 10 to 50mM.
9. 9. The method according to claim 1 or 4, wherein the concentration of periodate in the reaction solution is 5 to 40mM.
10. 10. The method according to claim 1, wherein the concentration of H 2 O 2 in the reaction solution is 4.9 to 38.8mM.

Description

Method for advanced treatment of organic pollutants in lignite gasification biochemical wastewater by using far ultraviolet light activated oxidant Technical Field The invention belongs to the technical field of water treatment, and particularly relates to a method for deeply treating organic pollutants in lignite gasification biochemical wastewater by using an extreme ultraviolet activating oxidant. Background The lignite gasification technology is an important part of the coal chemical industry, but lignite gasification wastewater generated in the gasification process is complex in component, high in COD (chemical oxygen demand), high in chromaticity and strong in toxicity, and contains refractory heterocyclic compounds (pyridine and quinoline) and is still 600-900 mg/L after biochemical treatment, so that the lignite gasification technology is a bottleneck for restricting the development of the industry. Aiming at the degradation-resistant wastewater subjected to aerobic and anaerobic biochemical treatment, most enterprises commonly adopt a Fenton method for advanced treatment after multistage pretreatment. The related art discloses a biochemical tail water advanced treatment method, which comprises the treatment steps of coagulating sedimentation, fenton oxidation and adsorption filtration of biochemical tail water in sequence, wherein the Fenton oxidation step strengthens the generation of hydroxyl free radicals by regulating and controlling the pH value and the addition amount of Fe 2+, and aims to remove refractory organic matters and chromaticity remained in wastewater. However, the existing treatment mode still has a plurality of practical problems due to the influence of the water quality characteristics of the biochemical tail water: (1) The traditional Fenton method depends on the addition of a large amount of chemical agents, so that a large amount of iron-containing sludge can be generated to cause secondary pollution, if the sludge is not subjected to standard solidification landfill or recycling treatment, the infiltration of percolate to pollute soil and underground water is very easy to form serious secondary pollution risk, and the pressure and cost of subsequent environment-friendly treatment are increased; (2) The pH value of the wastewater is strictly required, the energy consumption in the acid-base regulation process is higher, the treatment system is required to be additionally provided with an acid-base regulation unit, the pH value of the wastewater is reduced to a specified range by adding concentrated sulfuric acid, and alkaline agents such as sodium hydroxide are required to be added to neutralize to neutrality after the reaction is finished, so that a large amount of acid-base agents are consumed in the whole process, high energy consumption can be generated due to continuous operation of regulating equipment, and the energy consumption cost of the acid-base regulation link accounts for 15-20% of the total treatment cost particularly when treating large-volume wastewater, thereby obviously reducing the process economy. (3) The treatment efficiency aiming at low-concentration refractory organic matters is easily influenced by water quality fluctuation, so that the stability of effluent indexes is poor, and the conditions frequently occur that the effluent indexes are not up to standard, namely when the COD load of inflow water, pollutant components or salinity change, the generation efficiency of free radicals in a Fenton reaction system can be severely fluctuated, so that the oxidative degradation of target pollutants is not thorough; (4) Although the Fenton method realizes the cooperation of multi-stage treatment, the Fenton oxidation unit has a long reaction period, and the filter material needs to be replaced periodically in the subsequent adsorption filtration, so that the operation and maintenance cost and the shutdown loss of equipment are increased, and the economical efficiency and the continuity of the whole process are required to be improved. Disclosure of Invention In view of the above, the invention aims to provide a method for deeply treating organic pollutants in lignite gasified biochemical wastewater by using an extreme ultraviolet activated oxidant, which can effectively degrade the organic pollutants in lignite gasified biochemical wastewater, especially the organic pollutants difficult to degrade, has the organic matter removal rate of more than or equal to 90%, can reach the standard and discharge, shortens the treatment period (the total reaction time is 2-4 hours, and the COD reaches the discharge standard according to COD (that is, the COD reaches below 80 mg/L)), has strong environmental adaptability, and solves the problems of large dosage of chemical in the traditional Fenton method, poor adaptability of the pH value of wastewater, unstable treatment efficiency of low-concentration organic matters difficult to degrade, long process reaction period an