Industrial wastewater treatment process

Abstract

The present invention discloses an industrial wastewater treatment process, which belongs to the field of environmental protection technology and sewage treatment technology. The organic matter in the industrial wastewater is concentrated by ultrafiltration equipment, the concentrated water is subjected to advanced oxidation treatment, the fresh water is subjected to biochemical treatment, and different process treatment methods are selected according to the acidity and alkalinity of the water quality. The reasonable combination of multiple processes to treat industrial wastewater can greatly reduce the amount of acid and alkali agents, avoid increasing the salt content, and reduce operating costs. Ozone oxidation is used to increase the dissolved oxygen in the water, combined with the Fenton oxidation system and the residual iron after iron-carbon micro-electrolysis treatment, so that Fe 3+ Under alkaline conditions, flocs are formed to promote the removal of organic matter while participating in the anaerobic nitrogen removal in the two-stage A / O treatment system, effectively removing ammonia nitrogen from the wastewater. The treated industrial wastewater quality meets the Class A standard of GB / T18918-2002 "Pollutant Discharge Standard for Urban Wastewater Treatment Plants".

Description

Technical Field

[0001] The invention belongs to the field of environmental protection technology and sewage treatment technology, and specifically relates to an industrial wastewater treatment process. Background Art

[0002] With the rapid development of chemical enterprises, the discharge of chemical wastewater has increased, and the load on the environment has intensified. At the same time, chemical wastewater in industrial parks has the characteristics of high salinity, difficulty in degradation, and complex composition, which makes it difficult to treat. With the continuous promotion of wastewater resource utilization, the demand for wastewater reuse in industrial parks has gradually increased. Some parks have high requirements for the quality of recycled water, and the efficient treatment process of industrial wastewater generated by industrial parks faces challenges.

[0003] Since chemical wastewater is difficult to completely degrade using traditional treatment methods such as sedimentation and filtration, the Fenton process can quickly oxidize and decompose organic matter in the wastewater in a relatively short period of time without the risk of secondary pollution, and is very effective in chemical wastewater treatment.

[0004] The Fenton oxidation process is a system composed of ferrous ions and hydrogen peroxide, which can generate highly oxidizing hydroxyl radicals, which react with refractory organic matter in aqueous solution to generate organic free radicals, destroying their structure and eventually oxidizing and decomposing them. The Fenton process has strong oxidation capacity and can handle a variety of toxic substances, but there are certain defects in practical applications.

[0005] Fenton oxidation method requires the pH of the influent to be between 2 and 4. Under acidic conditions, Fe 2+ Easily oxidized to Fe 3+ , thereby promoting the generation of hydroxyl radicals and increasing the reaction rate. However, too low a pH value will cause Fe 3+ After Fenton oxidation, the pH of the water needs to be adjusted to neutral for subsequent treatment. Therefore, strict pH control leads to the consumption of a large amount of acid and alkali reagents, resulting in increased costs. In addition, a single treatment method cannot treat industrial wastewater and cannot meet the treatment standards. Summary of the invention

[0006] The object of the present invention is to provide an industrial wastewater treatment process, which can reduce the consumption of acid and alkali for adjusting pH and thus reduce the operating cost under the premise of ensuring that the wastewater reaches the standard.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] The present invention provides an industrial wastewater treatment process, comprising the following steps:

[0009] (1) Transporting industrial wastewater to the pretreatment system to obtain pretreatment liquid;

[0010] (2) The pre-treated liquid is transported to the ultrafiltration equipment, and after concentration and filtration, ultrafiltration concentrated water and ultrafiltration fresh water are obtained. The ultrafiltration equipment concentrates the macromolecular organic pollutants in the wastewater to form concentrated water, and the content of macromolecular organic matter that is difficult to degrade in the fresh water is significantly reduced;

[0011] (3) The ultrafiltration concentrate and fresh water are transported to the concentrate storage tank and fresh water storage tank respectively, and the acidity and alkalinity of the water quality are determined according to the test results of the acid-base online monitoring system. When the pH of the ultrafiltration concentrate is ≥6.0, it is transferred to the ozone oxidation system; when the pH of the ultrafiltration concentrate is <6.0, it is transferred to the Fenton oxidation system; when the pH of the ultrafiltration fresh water is ≥6.0, it is transferred to the fresh water alkaline regulating tank; when the pH of the ultrafiltration fresh water is <6.0, it is transferred to the fresh water acid regulating tank. Due to the complex sources of industrial wastewater and large changes in water quality, it will be acidic for a period of time and alkaline for another period of time. The subsequent deep treatment processes are different, and the corresponding influent pH requirements are different. Direct unified deep treatment without distinguishing between acidity and alkalinity requires a large amount of acid and alkali reagents for adjustment, which consumes a large amount of reagents and has high costs. A large amount of acid and alkali neutralization will increase the salt content of the wastewater and increase the treatment burden;

[0012] (4) The pH of the effluent from the freshwater alkaline regulating tank is adjusted to 7.0-8.0 and transferred to the hydrolysis acidification tank. The pH of the effluent from the freshwater acid regulating tank is adjusted to 3.0-4.0 and transferred to the iron-carbon micro-electrolysis equipment;

[0013] (5) The water treated by the Fenton oxidation system, the ozone oxidation system, the hydrolysis acidification tank, and the iron-carbon micro-electrolysis equipment is transferred to the two-stage A / O treatment system;

[0014] There is Fe in the mixed water of Fenton oxidation system, ozone oxidation system, hydrolysis acidification tank, and iron-carbon micro-electrolysis equipment. 3+ In the A / O treatment system, microorganisms use Fe 3+ As an electron acceptor, it oxidizes ammonia nitrogen into nitrite nitrogen, nitrate nitrogen or nitrogen gas. 3+ Reduced to Fe 2+ Through iron-type denitrification, microorganisms use the generated Fe 2+ It is an electron donor that reduces nitrate nitrogen to nitrite nitrogen or nitrogen gas, while Fe 2+ Oxidized to Fe 3+ The remaining ammonia nitrogen and the nitrite nitrogen in the above two processes are eventually converted into nitrogen gas under the action of anaerobic ammonia-oxidizing bacteria, effectively removing ammonia nitrogen from the wastewater.

[0015] (6) The wastewater treated by the two-stage A / O treatment system is transported to a flocculation sedimentation tank, and the flocculant of the flocculation sedimentation tank is at least one of PAC and PAM;

[0016] (7) The effluent from the flocculation sedimentation tank is transported to the reverse osmosis device and then disinfected in the disinfection tank before being discharged to meet the discharge standards. The disinfection tank uses ultraviolet disinfection.

[0017] Preferably, the specific steps of the pretreatment system include: the wastewater passes through a coarse screen and a fine screen to remove suspended matter and large particle impurities.

[0018] Preferably, the ultrafiltration membrane used in the ultrafiltration equipment is made of PVDF material. The pH adaptability range of PVDF material is between 2-12, which is suitable for situations where the pH of industrial wastewater changes greatly. The ultrafiltration membrane molecular retention rate of the ultrafiltration equipment is 50kD. The larger retention rate is suitable for the separation and concentration of large molecules.

[0019] Preferably, the concentrate storage tank and the fresh water storage tank are installed with an acid-base online monitoring system to monitor the water quality pH in the storage tank in real time, and a stirrer is installed in the concentrate storage tank and the fresh water storage tank to mix the incoming water of different pH evenly in a short time.

[0020] Preferably, the specific steps of the ozone oxidation system include: the wastewater entering the ozone oxidation system is adjusted in pH by a concentrated water alkaline regulating tank and then enters an ozone contact oxidation tank, where ozone is added to react and degrade organic pollutants.

[0021] Preferably, the concentrated water alkaline regulating tank of the ozone oxidation system adjusts the inlet pH to 7.5-8.5, and the ozone dosage in the ozone contact oxidation tank is 100-200 mg / L.

[0022] Preferably, the specific steps of the Fenton oxidation system include: the wastewater entering the Fenton oxidation system is adjusted in the concentrated water acid adjustment tank and then enters the catalyst mixing tank, ferrous sulfate is added to the catalyst mixing tank and then mixed, and then transferred to the oxidation reaction tank, hydrogen peroxide solution is added to the oxidation reaction tank, and water is discharged after mixing reaction, thereby degrading the difficult-to-degrade organic pollutants into small molecular substances.

[0023] Preferably, the concentrate acidity regulating tank of the Fenton oxidation system adjusts the inlet pH to 3.0-4.0;

[0024] The mass ratio of ferrous sulfate to hydrogen peroxide solution in the Fenton oxidation system is 3.5-4.5, the mass concentration of hydrogen peroxide solution is 30%, and the dosage of hydrogen peroxide solution is 10-15 mL / L.

[0025] Preferably, the volume ratio of iron to carbon in the iron-carbon micro-electrolysis equipment is 1:1, and the amount of iron filings added is 20-30 g / L.

[0026] Preferably, the specific steps of the two-stage A / O treatment system include: the effluent from the Fenton oxidation system and the ozone oxidation system enters the concentrated water A / O treatment water storage tank, the effluent from the hydrolysis acidification tank and the iron-carbon micro-electrolysis equipment enters the fresh water A / O treatment water storage tank, the effluents from the concentrated water A / O treatment water storage tank and the fresh water A / O treatment water storage tank both enter the comprehensive regulating tank, and after adjusting the pH, they enter the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank, the secondary aerobic tank and the horizontal flow sedimentation tank in sequence to degrade organic macromolecules while removing nitrogen and phosphorus.

[0027] Preferably, the comprehensive regulating tank adjusts the influent pH to 7.0-7.5.

[0028] Beneficial effects of the present invention:

[0029] (1) The present invention uses ultrafiltration equipment to concentrate, and uses an advanced oxidation process to treat the concentrated water containing difficult-to-degrade high-molecular organic matter. The fresh water containing some organic pollutants is treated by hydrolysis acidification and iron-carbon micro-electrolysis to improve its biodegradability. The concentrated water and fresh water are then concentrated for two-stage A / O biochemical treatment. The advanced oxidation process is used to degrade toxic organic pollutants, improve the activity of biochemical treatment microorganisms, and improve the treatment efficiency by differentiating the concentrated water and fresh water. The sewage treatment effect is good, and the effluent meets the Class A standard of GB / T18918-2002 "Pollutant Discharge Standard for Urban Sewage Treatment Plants".

[0030] (2) The present invention monitors the pH value of water online, separates acidic water and alkaline water for treatment according to the characteristics of the water quality, and enters different subsequent treatment systems to control the pH value of the water entering each treatment system. This can greatly reduce the consumption of acid and alkali reagents during adjustment, avoid increasing the salt content in the water, reduce the treatment burden, and improve the treatment efficiency.

[0031] (3) The present invention performs A / O biochemical treatment after comprehensive adjustment of water treated by Fenton oxidation, ozone oxidation, hydrolysis acidification and iron-carbon micro-electrolysis, and mixes the alkaline effluent after ozone oxidation treatment with the effluent after Fenton oxidation treatment to make Fe 3+ Form colloids to enhance the purification effect of wastewater, and use the dissolved oxygen in the ozonated water to promote the Fe in the effluent from the iron-carbon micro-electrolysis 2+ Oxidation to form Fe 3+ , further enhance the flocculation effect. Based on the characteristics of water quality after different treatments, mixing in the comprehensive regulating tank can not only reduce the dosage of acid-base regulating agents, but also balance the concentration of substances in the water to adapt to subsequent A / O biochemical treatment. In the A / O treatment process, iron is used as a catalyst for the coupled denitrification process to reduce the ammonia nitrogen and total nitrogen content in the water, and the effluent quality is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below in conjunction with the accompanying drawings.

[0033] Figure 1It is a process flow chart of industrial wastewater treatment according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The actual water quality of industrial wastewater inlet is shown in Table 1:

[0036] Table 1

[0037] <![CDATA[Water inflow rate m 3 / d]]> Influent pH COD mg / L <![CDATA[NH3-N concentration mg / L]]> SS concentration mg / L TN concentration mg / L TP concentration mg / L <![CDATA[BOD5mg / L]]> 1000 4.0-9.0 489-1205 52-121 114-530 97-158 6-26 162-433

[0038] Example 1

[0039] An industrial wastewater treatment process comprises the following steps:

[0040] (1) The industrial wastewater is pumped to the pretreatment system. The pretreatment system is equipped with a coarse screen with a screen gap of 50 mm and a fine screen with a screen gap of 10 mm. The industrial wastewater is filtered through the screen to remove suspended coarse matter and obtain the pretreatment liquid;

[0041] (2) The pre-treated liquid is transported to the ultrafiltration equipment by the lifting pump. The membrane component of the ultrafiltration equipment is a PVDF filter membrane with a molecular retention rate of 50KD;

[0042] (3) The concentrated water produced by the ultrafiltration equipment is transported to the concentrated water storage tank, and the fresh water is transported to the fresh water storage tank. Both storage tanks are equipped with an acid-base online monitoring system and a stirrer. The acidity and alkalinity of the wastewater after stirring and mixing is determined based on the test results.

[0043] When the pH of ultrafiltration concentrate is ≥6.0, it is transferred to the ozone oxidation system. The influent in the ozone oxidation system is adjusted to pH 7.5 in the concentrate alkaline regulating tank and then enters the ozone contact oxidation tank. The ozone dosage in the ozone contact oxidation tank is controlled at 100 mg / L.

[0044] When the pH value of ultrafiltration concentrate is less than 6.0, it is transferred to the Fenton oxidation system. The influent in the Fenton oxidation system is adjusted to pH 3.0 in the concentrate acid adjustment tank and then enters the catalyst mixing tank. 39 g / L ferrous sulfate is added to the catalyst mixing tank. The effluent enters the oxidation reaction tank. A hydrogen peroxide solution with a mass concentration of 30% is added at 10 mL / L in the oxidation reaction tank.

[0045] When the ultrafiltered fresh water has a pH value of ≥6.0, it is transferred to the fresh water alkaline regulating tank; when the ultrafiltered fresh water has a pH value of <6.0, it is transferred to the fresh water acidic regulating tank.

[0046] (4) The pH of the wastewater in the freshwater alkaline regulating tank was adjusted to 7.0, and the effluent entered the hydrolysis acidification tank. The pH of the wastewater in the freshwater acidic regulating tank was adjusted to 3.0, and the effluent entered the iron-carbon micro-electrolysis equipment. The iron-carbon volume in the iron-carbon micro-electrolysis equipment was set to 1:1, and the iron filings addition amount was 20 g / L.

[0047] (5) The water treated by the Fenton oxidation system, the ozone oxidation system, the hydrolysis acidification tank, and the iron-carbon micro-electrolysis equipment is pumped into the two-stage A / O treatment system through a water pump. The effluents of the Fenton oxidation system and the ozone oxidation system enter the concentrated water A / O treatment water storage tank, and the effluents of the hydrolysis acidification tank and the iron-carbon micro-electrolysis equipment enter the fresh water A / O treatment water storage tank, and are then pumped into the comprehensive regulating tank. An acid-base online monitoring system and an agitator are installed in the comprehensive regulating tank. Acid-base reagents are added according to the detection results of the acid-base online monitoring system. The pH value of the wastewater in the regulating tank is 7.0. After regulation, the effluent enters the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank, the secondary aerobic tank, and the horizontal flow sedimentation tank for treatment in turn.

[0048] (6) The wastewater after the two-stage A / O treatment system is transported to the flocculation sedimentation tank. The flocculants used in the flocculation sedimentation tank are PAC and PAM. The PAC dosage is 100 mg / L and the PAM dosage is 3 mg / L.

[0049] (7) The effluent from the flocculation sedimentation tank is transported to the reverse osmosis device and then disinfected by ultraviolet light in the disinfection tank before being discharged in compliance with the discharge standards.

[0050] Example 2

[0051] The difference from Example 1 is that the pH of the concentrated water acid adjustment tank in the Fenton oxidation system is adjusted to 3.5, 57 g / L of ferrous sulfate is added to the catalyst mixing tank, and a hydrogen peroxide solution with a mass concentration of 30% is added to the oxidation reaction tank at 13 mL / L. The other process parameters and process steps are the same as in Example 1.

[0052] Example 3

[0053] The difference from Example 1 is that the pH of the concentrated water acid adjustment tank in the Fenton oxidation system is adjusted to 4.0, 74 g / L of ferrous sulfate is added to the catalyst mixing tank, and a hydrogen peroxide solution with a mass concentration of 30% is added to the oxidation reaction tank at 15 mL / L. The other process parameters and process steps are the same as in Example 1.

[0054] Example 4

[0055] The difference from Example 1 is that the pH of the concentrated water alkaline regulating tank in the ozone oxidation system is adjusted to 8.0, the ozone dosage in the ozone contact oxidation tank is 150 mg / L, and the other process parameters and process steps are the same as Example 1.

[0056] Example 5

[0057] The difference from Example 1 is that the pH of the concentrated water alkaline regulating tank in the ozone oxidation system is adjusted to 8.5, the ozone dosage in the ozone contact oxidation tank is 200 mg / L, and the other process parameters and process steps are the same as Example 1.

[0058] Example 6

[0059] The difference from Example 1 is that the amount of iron filings added to the iron-carbon micro-electrolysis equipment is 25 g / L, and the other process parameters and process steps are the same as Example 1.

[0060] Example 7

[0061] The difference from Example 1 is that the amount of iron filings added to the iron-carbon micro-electrolysis equipment is 30 g / L, and the other process parameters and process steps are the same as Example 1.

[0062] Example 8

[0063] An industrial wastewater treatment process comprises the following steps:

[0064] (1) The industrial wastewater is pumped to the pretreatment system. The pretreatment system is equipped with a coarse screen with a screen gap of 50 mm and a fine screen with a screen gap of 10 mm. The industrial wastewater is filtered through the screen to remove suspended coarse matter and obtain the pretreatment liquid;

[0065] (2) The pre-treated liquid is transported to the ultrafiltration equipment by the lifting pump. The membrane component of the ultrafiltration equipment is a PVDF filter membrane with a molecular retention rate of 50KD;

[0066] (3) The concentrated water produced by the ultrafiltration equipment is transported to the concentrated water storage tank, and the fresh water is transported to the fresh water storage tank. Both storage tanks are equipped with an acid-base online monitoring system and a stirrer. The acidity and alkalinity of the wastewater after stirring and mixing is determined based on the test results.

[0067] When the pH of ultrafiltration concentrate is ≥6.0, it is transferred to the ozone oxidation system. The influent in the ozone oxidation system is adjusted to pH 8.0 in the concentrate alkaline regulating tank and then enters the ozone contact oxidation tank. The ozone dosage in the ozone contact oxidation tank is controlled at 150 mg / L.

[0068] When the pH value of ultrafiltration concentrate is less than 6.0, it is transferred to the Fenton oxidation system. The influent in the Fenton oxidation system is adjusted to pH 3.5 in the concentrate acid adjustment tank and then enters the catalyst mixing tank. 57 g / L of ferrous sulfate is added to the catalyst mixing tank. The effluent enters the oxidation reaction tank. A hydrogen peroxide solution with a mass concentration of 30% is added at 13 mL / L in the oxidation reaction tank.

[0069] When the ultrafiltered fresh water has a pH value of ≥6.0, it is transferred to the fresh water alkaline regulating tank; when the ultrafiltered fresh water has a pH value of <6.0, it is transferred to the fresh water acidic regulating tank.

[0070] (4) The pH of the wastewater in the freshwater alkaline regulating tank was adjusted to 7.5, and the effluent entered the hydrolysis acidification tank. The pH of the wastewater in the freshwater acidic regulating tank was adjusted to 3.5, and the effluent entered the iron-carbon micro-electrolysis equipment. The iron-carbon volume in the iron-carbon micro-electrolysis equipment was set to 1:1, and the iron filings addition amount was 25 g / L.

[0071] (5) The water treated by the Fenton oxidation system, the ozone oxidation system, the hydrolysis acidification tank, and the iron-carbon micro-electrolysis equipment is pumped into the two-stage A / O treatment system through a water pump. The effluents of the Fenton oxidation system and the ozone oxidation system enter the concentrated water A / O treatment water storage tank, and the effluents of the hydrolysis acidification tank and the iron-carbon micro-electrolysis equipment enter the fresh water A / O treatment water storage tank, and are then pumped into the comprehensive regulating tank. An acid-base online monitoring system and an agitator are installed in the comprehensive regulating tank. Acid-base reagents are added according to the detection results of the acid-base online monitoring system. The pH value of the wastewater in the regulating tank is 7.0. After regulation, the effluent enters the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank, the secondary aerobic tank, and the horizontal flow sedimentation tank for treatment in turn.

[0072] (6) The wastewater after the two-stage A / O treatment system is transported to the flocculation sedimentation tank. The flocculants used in the flocculation sedimentation tank are PAC and PAM. The PAC dosage is 100 mg / L and the PAM dosage is 3 mg / L.

[0073] (7) The effluent from the flocculation sedimentation tank is transported to the reverse osmosis device and then disinfected by ultraviolet light in the disinfection tank before being discharged in compliance with the discharge standards.

[0074] Example 9

[0075] An industrial wastewater treatment process comprises the following steps:

[0076] (1) The industrial wastewater is pumped to the pretreatment system. The pretreatment system is equipped with a coarse screen with a screen gap of 50 mm and a fine screen with a screen gap of 10 mm. The industrial wastewater is filtered through the screen to remove suspended coarse matter and obtain the pretreatment liquid;

[0077] (2) The pre-treated liquid is transported to the ultrafiltration equipment by the lifting pump. The membrane component of the ultrafiltration equipment is a PVDF filter membrane with a molecular retention rate of 50KD;

[0078] (3) The concentrated water produced by the ultrafiltration equipment is transported to the concentrated water storage tank, and the fresh water is transported to the fresh water storage tank. Both storage tanks are equipped with an acid-base online monitoring system and a stirrer. The acidity and alkalinity of the wastewater after stirring and mixing is determined based on the test results.

[0079] When the pH of ultrafiltration concentrate is ≥6.0, it is transferred to the ozone oxidation system. The influent in the ozone oxidation system is adjusted to pH 8.0 in the concentrate alkaline regulating tank and then enters the ozone contact oxidation tank. The ozone dosage in the ozone contact oxidation tank is controlled at 150 mg / L.

[0080] When the pH value of ultrafiltration concentrate is less than 6.0, it is transferred to the Fenton oxidation system. The influent in the Fenton oxidation system is adjusted to pH 3.5 in the concentrate acid adjustment tank and then enters the catalyst mixing tank. 57 g / L of ferrous sulfate is added to the catalyst mixing tank. The effluent enters the oxidation reaction tank. A hydrogen peroxide solution with a mass concentration of 30% is added at 13 mL / L in the oxidation reaction tank.

[0081] When the ultrafiltered fresh water has a pH value of ≥6.0, it is transferred to the fresh water alkaline regulating tank; when the ultrafiltered fresh water has a pH value of <6.0, it is transferred to the fresh water acidic regulating tank.

[0082] (4) The pH of the wastewater in the freshwater alkaline regulating tank was adjusted to 8.0, and the effluent entered the hydrolysis acidification tank. The pH of the wastewater in the freshwater acidic regulating tank was adjusted to 4.0, and the effluent entered the iron-carbon micro-electrolysis equipment. The iron-carbon volume in the iron-carbon micro-electrolysis equipment was set to 1:1, and the iron filings addition amount was 25 g / L.

[0083] (5) The water treated by the Fenton oxidation system, the ozone oxidation system, the hydrolysis acidification tank, and the iron-carbon micro-electrolysis equipment is pumped into the two-stage A / O treatment system through a water pump. The effluents of the Fenton oxidation system and the ozone oxidation system enter the concentrated water A / O treatment water storage tank, and the effluents of the hydrolysis acidification tank and the iron-carbon micro-electrolysis equipment enter the fresh water A / O treatment water storage tank, and are then pumped into the comprehensive regulating tank. An acid-base online monitoring system and an agitator are installed in the comprehensive regulating tank. Acid-base reagents are added according to the detection results of the acid-base online monitoring system. The pH value of the wastewater in the regulating tank is 7.5. After regulation, the effluent enters the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank, the secondary aerobic tank, and the horizontal flow sedimentation tank for treatment in turn.

[0084] (6) The wastewater after the two-stage A / O treatment system is transported to the flocculation sedimentation tank. The flocculants used in the flocculation sedimentation tank are PAC and PAM. The PAC dosage is 100 mg / L and the PAM dosage is 3 mg / L.

[0085] (7) The effluent from the flocculation sedimentation tank is transported to the reverse osmosis device and then disinfected by ultraviolet light in the disinfection tank before being discharged in compliance with the discharge standards.

[0086] Comparative Example 1

[0087] The difference from Example 8 is that the ultrafiltration concentrated water in the process flow of industrial wastewater is treated by Fenton oxidation system, and the ultrafiltration fresh water is treated by iron-carbon micro-electrolysis equipment. The specific steps are as follows:

[0088] (1) The industrial wastewater is pumped to the pretreatment system. The pretreatment system is equipped with a coarse screen with a screen gap of 50 mm and a fine screen with a screen gap of 10 mm. The industrial wastewater is filtered through the screen to remove suspended coarse matter and obtain the pretreatment liquid;

[0089] (2) The pre-treated liquid is transported to the ultrafiltration equipment by the lifting pump. The membrane component of the ultrafiltration equipment is a PVDF filter membrane with a molecular retention rate of 50KD;

[0090] (3) The concentrated water produced by the ultrafiltration equipment is transported to the concentrated water storage tank, and the fresh water is transported to the fresh water storage tank. Agitators are installed in both storage tanks to stir and mix the wastewater.

[0091] The ultrafiltration concentrated water is transferred to the Fenton oxidation system. The influent in the Fenton oxidation system is adjusted to pH 3.5 in the concentrated water acid adjustment tank and then enters the catalyst mixing tank. 57g / L ferrous sulfate is added to the catalyst mixing tank. The effluent enters the oxidation reaction tank. The mass concentration of 30% hydrogen peroxide solution is added at 13mL / L. The ultrafiltration fresh water is transferred to the fresh water acid adjustment tank.

[0092] (4) The pH value of the wastewater in the freshwater acidification regulating tank was adjusted to 3.5, and the effluent entered the iron-carbon micro-electrolysis equipment. The iron-carbon volume in the iron-carbon micro-electrolysis equipment was set to 1:1, and the iron filings dosage was 25 g / L.

[0093] (5) The water treated by the Fenton oxidation system and the iron-carbon micro-electrolysis equipment is pumped into the two-stage A / O treatment system through a water pump. The effluent from the Fenton oxidation system enters the concentrated water A / O treatment storage tank, and the effluent from the iron-carbon micro-electrolysis equipment enters the fresh water A / O treatment storage tank, and then is pumped into the comprehensive regulating tank. An acid-base online monitoring system and an agitator are installed in the comprehensive regulating tank. Acid-base reagents are added according to the detection results of the acid-base online monitoring system. The pH value of the wastewater in the regulating tank is 7.0. After regulation, the effluent enters the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank, the secondary aerobic tank and the horizontal flow sedimentation tank for treatment in turn.

[0094] (6) The wastewater after the two-stage A / O treatment system is transported to the flocculation sedimentation tank. The flocculants used in the flocculation sedimentation tank are PAC and PAM. The PAC dosage is 100 mg / L and the PAM dosage is 3 mg / L.

[0095] (7) The effluent from the flocculation sedimentation tank is transported to the reverse osmosis device, and after being treated, it is disinfected by ultraviolet light in the disinfection tank to obtain the effluent.

[0096] Comparative Example 2

[0097] The difference from Example 8 is that the ultrafiltration concentrated water in the process flow of industrial wastewater is treated by an ozone oxidation system, and the ultrafiltration fresh water is treated by a hydrolysis acidification tank. The specific steps are as follows:

[0098] (1) The industrial wastewater is pumped to the pretreatment system. The pretreatment system is equipped with a coarse screen with a screen gap of 50 mm and a fine screen with a screen gap of 10 mm. The industrial wastewater is filtered through the screen to remove suspended coarse matter and obtain the pretreatment liquid;

[0099] (2) The pre-treated liquid is transported to the ultrafiltration equipment by the lifting pump. The membrane component of the ultrafiltration equipment is a PVDF filter membrane with a molecular retention rate of 50KD;

[0100] (3) The concentrated water produced by the ultrafiltration equipment is transported to the concentrated water storage tank, and the fresh water is transported to the fresh water storage tank. Agitators are installed in both storage tanks to stir and mix the wastewater.

[0101] The ultrafiltration concentrated water is transferred to the ozone oxidation system. The water in the ozone oxidation system is adjusted to pH 8.0 in the concentrated water alkaline regulating tank and then enters the ozone contact oxidation tank. The ozone dosage of the ozone contact oxidation tank is controlled at 150 mg / L. The ultrafiltration fresh water is transferred to the fresh water alkaline regulating tank.

[0102] (4) The pH of the wastewater in the freshwater alkaline regulating tank is adjusted to 7.5, and the effluent enters the hydrolysis acidification tank.

[0103] (5) The water treated by the ozone oxidation system and the hydrolysis acidification tank is pumped into the two-stage A / O treatment system through a water pump. The effluent from the ozone oxidation system enters the concentrated water A / O treatment storage tank, and the effluent from the hydrolysis acidification tank enters the fresh water A / O treatment storage tank, and then is pumped into the comprehensive regulating tank. An acid-base online monitoring system and an agitator are installed in the comprehensive regulating tank. Acid-base reagents are added according to the detection results of the acid-base online monitoring system. The pH value of the wastewater in the regulating tank is 7.0. After regulation, the effluent enters the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank, the secondary aerobic tank and the horizontal flow sedimentation tank for treatment in turn.

[0104] (6) The wastewater after the two-stage A / O treatment system is transported to the flocculation sedimentation tank. The flocculants used in the flocculation sedimentation tank are PAC and PAM. The PAC dosage is 100 mg / L and the PAM dosage is 3 mg / L.

[0105] (7) The effluent from the flocculation sedimentation tank is transported to the reverse osmosis device, and after being treated, it is disinfected by ultraviolet light in the disinfection tank to obtain the effluent.

[0106] Comparative Example 3

[0107] The difference from Example 8 is that the ultrafiltration concentrated water in the process flow of industrial wastewater is treated by Fenton oxidation system, and the ultrafiltration fresh water is treated by hydrolysis acidification tank. The specific steps are as follows:

[0108] (1) The industrial wastewater is pumped to the pretreatment system. The pretreatment system is equipped with a coarse screen with a screen gap of 50 mm and a fine screen with a screen gap of 10 mm. The industrial wastewater is filtered through the screen to remove suspended coarse matter and obtain the pretreatment liquid;

[0109] (2) The pre-treated liquid is transported to the ultrafiltration equipment by the lifting pump. The membrane component of the ultrafiltration equipment is a PVDF filter membrane with a molecular retention rate of 50KD;

[0110] (3) The concentrated water produced by the ultrafiltration equipment is transported to the concentrated water storage tank, and the fresh water is transported to the fresh water storage tank. Agitators are installed in both storage tanks to stir and mix the wastewater.

[0111] The ultrafiltration concentrated water is transferred to the Fenton oxidation system. The influent in the Fenton oxidation system is adjusted to pH 3.5 in the concentrated water acidic regulating tank and then enters the catalyst mixing tank. 57g / L ferrous sulfate is added to the catalyst mixing tank. The effluent enters the oxidation reaction tank. The hydrogen peroxide solution with a mass concentration of 30% is added at 13mL / L. The ultrafiltration dilute is transferred to the fresh water alkaline regulating tank.

[0112] (4) The pH of the wastewater in the freshwater alkaline regulating tank is adjusted to 7.5, and the effluent enters the hydrolysis acidification tank.

[0113] (5) The water treated by the Fenton oxidation system and the hydrolysis acidification tank is pumped into the two-stage A / O treatment system through a water pump. The effluent from the Fenton oxidation system enters the concentrated water A / O treatment storage tank, and the effluent from the hydrolysis acidification tank enters the fresh water A / O treatment storage tank, and then is pumped into the comprehensive regulating tank. An acid-base online monitoring system and an agitator are installed in the comprehensive regulating tank. Acid-base reagents are added according to the detection results of the acid-base online monitoring system. The pH value of the wastewater in the regulating tank is 7.0. After adjustment, the effluent enters the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank, the secondary aerobic tank and the horizontal flow sedimentation tank for treatment.

[0114] (6) The wastewater after the two-stage A / O treatment system is transported to the flocculation sedimentation tank. The flocculants used in the flocculation sedimentation tank are PAC and PAM. The PAC dosage is 100 mg / L and the PAM dosage is 3 mg / L.

[0115] (7) The effluent from the flocculation sedimentation tank is transported to the reverse osmosis device, and after being treated, it is disinfected by ultraviolet light in the disinfection tank to obtain the effluent.

[0116] Comparative Example 4

[0117] The difference from Example 8 is that the ultrafiltration concentrated water in the process flow of industrial wastewater is treated by an ozone oxidation system, and the ultrafiltration fresh water is treated by an iron-carbon micro-electrolysis device. The specific steps are as follows:

[0118] (1) The industrial wastewater is pumped to the pretreatment system. The pretreatment system is equipped with a coarse screen with a screen gap of 50 mm and a fine screen with a screen gap of 10 mm. The industrial wastewater is filtered through the screen to remove suspended coarse matter and obtain the pretreatment liquid;

[0119] (2) The pre-treated liquid is transported to the ultrafiltration equipment by the lifting pump. The membrane component of the ultrafiltration equipment is a PVDF filter membrane with a molecular retention rate of 50KD;

[0120] (3) The concentrated water produced by the ultrafiltration equipment is transported to the concentrated water storage tank, and the fresh water is transported to the fresh water storage tank. Agitators are installed in both storage tanks to stir and mix the wastewater.

[0121] The ultrafiltration concentrate is transferred to the ozone oxidation system. The influent in the ozone oxidation system is adjusted to pH 8.0 in the concentrate alkaline regulating tank and then enters the ozone contact oxidation tank. The ozone dosage in the ozone contact oxidation tank is controlled at 150 mg / L.

[0122] The ultrafiltered fresh water is transferred to the fresh water acidity regulating tank.

[0123] (4) The pH value of the wastewater in the freshwater acidification regulating tank was adjusted to 3.5, and the effluent entered the iron-carbon micro-electrolysis equipment. The iron-carbon volume in the iron-carbon micro-electrolysis equipment was set to 1:1, and the iron filings dosage was 25 g / L.

[0124] (5) The water treated by the ozone oxidation system and the iron-carbon micro-electrolysis equipment is pumped into the two-stage A / O treatment system through a water pump. The effluent from the ozone oxidation system enters the concentrated water A / O treatment storage tank, and the effluent from the iron-carbon micro-electrolysis equipment enters the fresh water A / O treatment storage tank, and then is pumped into the comprehensive regulating tank. An acid-base online monitoring system and an agitator are installed in the comprehensive regulating tank. Acid-base reagents are added according to the detection results of the acid-base online monitoring system. The pH value of the wastewater in the regulating tank is 7.0. After adjustment, the effluent enters the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank, the secondary aerobic tank and the horizontal flow sedimentation tank for treatment.

[0125] (6) The wastewater after the two-stage A / O treatment system is transported to the flocculation sedimentation tank. The flocculants used in the flocculation sedimentation tank are PAC and PAM. The PAC dosage is 100 mg / L and the PAM dosage is 3 mg / L.

[0126] (7) The effluent from the flocculation sedimentation tank is transported to the reverse osmosis device, and after being treated, it is disinfected by ultraviolet light in the disinfection tank to obtain the effluent.

[0127] Comparative Example 5

[0128] The difference from Example 8 is that no ultrafiltration equipment is used in the process flow of industrial wastewater, and the pre-treated liquid directly enters the Fenton oxidation system for treatment. The specific steps are as follows:

[0129] (1) The industrial wastewater is pumped to the pretreatment system. The pretreatment system is equipped with a coarse screen with a screen gap of 50 mm and a fine screen with a screen gap of 10 mm. The industrial wastewater is filtered through the screen to remove suspended coarse matter and obtain the pretreatment liquid;

[0130] (2) The pretreatment liquid is transferred to the Fenton oxidation system. The influent in the Fenton oxidation system is adjusted to pH 3.5 in the acid adjustment tank and then enters the catalyst mixing tank. 57 g / L of ferrous sulfate is added to the catalyst mixing tank. The effluent enters the oxidation reaction tank. A hydrogen peroxide solution with a mass concentration of 30% is added at 13 mL / L.

[0131] (3) The water treated by the Fenton oxidation system is pumped into the two-stage A / O treatment system through a water pump. The effluent from the Fenton oxidation system is pumped into the comprehensive regulating tank. An acid-base online monitoring system and an agitator are installed in the comprehensive regulating tank. Acid-base reagents are added according to the detection results of the acid-base online monitoring system. The pH value of the wastewater in the regulating tank is 7.0. After regulation, the effluent enters the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank, the secondary aerobic tank and the horizontal flow sedimentation tank for treatment in sequence.

[0132] (4) The wastewater after the two-stage A / O treatment system is transported to the flocculation sedimentation tank. The flocculants used in the flocculation sedimentation tank are PAC and PAM. The PAC dosage is 100 mg / L and the PAM dosage is 3 mg / L.

[0133] (5) The effluent from the flocculation sedimentation tank is transported to the reverse osmosis device, and after being treated, it is disinfected by ultraviolet light in the disinfection tank to obtain the effluent.

[0134] Comparative Example 6

[0135] The difference from Example 8 is that no ultrafiltration equipment is used in the process flow of industrial wastewater, and the pre-treated liquid directly enters the ozone oxidation system for treatment. The specific steps are as follows:

[0136] (1) The industrial wastewater is pumped to the pretreatment system. The pretreatment system is equipped with a coarse screen with a screen gap of 50 mm and a fine screen with a screen gap of 10 mm. The industrial wastewater is filtered through the screen to remove suspended coarse matter and obtain the pretreatment liquid;

[0137] (2) The pre-treated liquid is transferred to the ozone oxidation system. The influent in the ozone oxidation system is adjusted to pH 8.0 in the concentrated water alkaline regulating tank and then enters the ozone contact oxidation tank. The ozone dosage in the ozone contact oxidation tank is controlled at 150 mg / L.

[0138] (3) The water treated by the ozone oxidation system is pumped into the two-stage A / O treatment system through a water pump, and the effluent from the ozone oxidation system is pumped into the comprehensive regulating tank. An acid-base online monitoring system and an agitator are installed in the comprehensive regulating tank. Acid-base reagents are added according to the detection results of the acid-base online monitoring system. The pH value of the wastewater in the regulating tank is 7.0. After regulation, the effluent enters the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank, the secondary aerobic tank and the horizontal flow sedimentation tank for treatment in sequence.

[0139] (4) The wastewater after the two-stage A / O treatment system is transported to the flocculation sedimentation tank. The flocculants used in the flocculation sedimentation tank are PAC and PAM. The PAC dosage is 100 mg / L and the PAM dosage is 3 mg / L.

[0140] (5) The effluent from the flocculation sedimentation tank is transported to the reverse osmosis device, and after being treated, it is disinfected by ultraviolet light in the disinfection tank to obtain the effluent.

[0141] The water quality of the effluent obtained after all the process treatments in Examples 1 to 9 and Comparative Examples 1 to 6 was tested, and the results are shown in Table 2:

[0142] Table 2

[0143] Example Outlet pH COD mg / L <![CDATA[NH3-N concentration mg / L]]> SS concentration mg / L TN concentration mg / L TP concentration mg / L <![CDATA[BOD5mg / L]]> <![CDATA[Operating cost yuan / m 3 > Example 1 7.2 23.2 2.6 2.0 6.5 0.3 5.7 1.1 Example 2 7.1 20.1 1.5 1.6 4.1 0.2 3.3 1.2 Example 3 7.2 22.7 2.5 1.7 5.9 0.2 4.6 1.4 Example 4 7.2 22.1 2.0 1.7 5.3 0.2 4.3 1.2 Example 5 7.1 21.6 1.8 1.5 4.4 0.1 3.7 1.4 Example 6 7.2 22.8 1.6 1.6 4.2 0.1 4.5 1.2 Example 7 7.1 22.5 1.8 1.5 4.5 0.1 4.2 1.3 Example 8 7.1 19.2 1.0 1.3 3.6 0.1 2.9 1.3 Example 9 7.4 19.4 1.3 1.4 3.9 0.2 3.1 1.3 Comparative Example 1 7.2 36.8 6.1 3.9 8.1 0.6 8.4 1.9 Comparative Example 2 7.2 45.3 8.2 5.0 12.3 1.1 10.5 1.8 Comparative Example 3 7.2 42.0 7.8 4.6 11.8 0.9 9.3 1.8 Comparative Example 4 7.2 42.9 7.9 4.8 12.0 1.0 9.7 1.9 Comparative Example 5 7.1 53.0 10.2 8.3 22.1 1.6 13.5 1.7 Comparative Example 6 7.2 64.9 15.5 10.1 29.8 2.2 16.3 1.8

[0144] As can be seen from Table 2, Examples 1-9 are treated separately according to the acidity and alkalinity of the wastewater and the ultrafiltration concentrated and fresh water, Comparative Examples 1-Comparative Example 4 are treated without distinguishing the acidity and alkalinity, and Comparative Examples 5 and Comparative Examples 6 are directly treated centrally without ultrafiltration and concentration treatment. The wastewater quality after treatment in the examples is significantly better than that in the comparative examples, and based on the characteristics of large changes in wastewater quality during operation, the process treatment operation of the examples has lower reagent consumption and lower operating costs. In Examples 1-3, the pH and reagent dosage of the water in the Fenton oxidation system are adjusted, wherein the conditions in Example 2 are more conducive to the treatment of the Fenton oxidation system, the removal efficiency of organic pollutants in the water is better, and since the iron in the catalyst participates in the ammonia nitrogen reaction in the A / O treatment, the ammonia nitrogen and total nitrogen can be better removed, but the excessive catalyst in Example 3 causes excessive iron content, inhibits the microbial activity in the A / O treatment, and reduces the ammonia nitrogen removal rate compared to Example 2. In Example 4 and Example 5, the pH of the ozone oxidation reaction and the amount of ozone added are adjusted on the basis of Example 1. In Example 5, excessive ozone addition will increase the operating cost, and the removal effect of pollutants in the water is less improved than that in Example 4. In Example 6 and Example 7, the amount of iron filings added in the iron-carbon micro-electrolysis equipment is increased, and the removal of precipitates is formed by the micro-electrolysis reaction products and phosphorus ions in the water, and the phosphorus removal effect is significant. In Example 8-Example 9, the adjustments of different processes in Example 2, Example 4 and Example 6 are adopted, and the pH of the wastewater entering the hydrolysis acidification tank and the iron-carbon micro-electrolysis equipment is further adjusted. Compared with Example 8, Example 9 has a high pH, ​​and the degradation efficiency is reduced in subsequent treatment.

[0145] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0146] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An industrial wastewater treatment process, characterized in that: The steps include: (1) Transporting industrial wastewater to the pretreatment system to obtain pretreatment liquid; (2) transporting the pretreated liquid to an ultrafiltration device to obtain ultrafiltration concentrated water and ultrafiltration fresh water; (3) The ultrafiltration concentrate and ultrafiltration fresh water are transported to the concentrate storage tank and fresh water storage tank respectively. When the pH of the ultrafiltration concentrate is ≥6.0, it is transferred to the ozone oxidation system; when the pH of the ultrafiltration concentrate is <6.0, it is transferred to the Fenton oxidation system; when the pH of the ultrafiltration fresh water is ≥6.0, it is transferred to the fresh water alkaline regulating tank; when the pH of the ultrafiltration fresh water is <6.0, it is transferred to the fresh water acid regulating tank; (4) The effluent from the freshwater alkaline regulating tank is adjusted to pH 7.0-8.0 and transferred to the hydrolysis acidification tank. The effluent from the freshwater acidic regulating tank is adjusted to pH 3.0-4.0 and transferred to the iron-carbon micro-electrolysis equipment; (5) The water treated by the Fenton oxidation system, the ozone oxidation system, the hydrolysis acidification tank, and the iron-carbon micro-electrolysis equipment is transferred to the two-stage A / O treatment system; (6) The wastewater treated by the two-stage A / O treatment system is transported to the flocculation sedimentation tank; (7) The effluent from the flocculation sedimentation tank is transported to the reverse osmosis device and then disinfected in the disinfection tank before being discharged to meet the discharge standards.

2. An industrial wastewater treatment process according to claim 1, characterized in that: The specific steps of the pretreatment system include: industrial wastewater is treated by a coarse grid and a fine grid to obtain a pretreatment liquid.

3. An industrial wastewater treatment process according to claim 1, characterized in that: The ultrafiltration membrane used in the ultrafiltration equipment is made of PVDF material, and the molecular retention rate of the ultrafiltration membrane is 50kD.

4. The industrial wastewater treatment process according to claim 1, characterized in that: The specific steps of the ozone oxidation system include: the inlet water of the ozone oxidation system is adjusted in pH by a concentrated water alkaline regulating tank and then enters an ozone contact oxidation tank.

5. An industrial wastewater treatment process according to claim 4, characterized in that: The concentrated water alkaline regulating tank of the ozone oxidation system adjusts the inlet pH to 7.5-8.5, and the ozone dosage in the ozone contact oxidation tank is 100-200 mg / L.

6. An industrial wastewater treatment process according to claim 1, characterized in that: The specific steps of the Fenton oxidation system include: the influent of the Fenton oxidation system is adjusted in the concentrated water acid adjustment tank and then enters the catalyst mixing tank, ferrous sulfate is added to the catalyst mixing tank and then mixed, and then transferred to the oxidation reaction tank, hydrogen peroxide solution is added to the oxidation reaction tank, and effluent is obtained after mixing reaction.

7. An industrial wastewater treatment process according to claim 6, characterized in that: The concentrated water acidity regulating tank of the Fenton oxidation system adjusts the inlet pH to 3.0-4.0; The mass ratio of ferrous sulfate to hydrogen peroxide solution in the Fenton oxidation system is 3.5-4.5, the mass concentration of hydrogen peroxide solution is 30%, and the dosage of hydrogen peroxide solution is 10-15 mL / L.

8. An industrial wastewater treatment process according to claim 1, characterized in that: The iron-carbon volume ratio in the iron-carbon micro-electrolysis equipment is 1:1, and the amount of iron chips added is 20-30 g / L.

9. An industrial wastewater treatment process according to claim 1, characterized in that: The specific steps of the two-stage A / O treatment system include: the effluents of the Fenton oxidation system and the ozone oxidation system enter the concentrated water A / O treatment water storage tank, the effluents of the hydrolysis acidification tank and the iron-carbon micro-electrolysis equipment enter the fresh water A / O treatment water storage tank, and the effluents of the concentrated water A / O treatment water storage tank and the fresh water A / O treatment water storage tank both enter the comprehensive regulating tank, and after pH adjustment, they enter the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank, the secondary aerobic tank and the horizontal flow sedimentation tank in sequence to degrade organic macromolecules and remove nitrogen and phosphorus at the same time.

10. An industrial wastewater treatment process according to claim 9, characterized in that: The comprehensive regulating tank adjusts the influent pH to 7.0-7.5.

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