Rapid sedimentation ECIS sewage treatment process

Abstract

The invention relates to the technical field of sewage treatment, and particularly discloses a rapid-settling ECIS sewage treatment process which comprises the following six stages: an electrolysis stage, an anaerobic stage in biochemical treatment, an anoxic stage in biochemical treatment, an aerobic stage in biochemical treatment, an electric flocculation stage and a filtering stage. In the electric flocculation stage, an ammonium polyacrylate flocculant and a photocatalyst are added, the ammonium polyacrylate flocculant is used for flocculation, the molecular weight and solid content of ammonium polyacrylate are high, the molecular weight reaches 21,110 thousand, the solid content reaches 33.29%, the emulsion flocculant is good in stability and water solubility and has good flocculation performance on red mud, the sedimentation rate can reach 5.8 mL / s, the turbidity of supernate is 105.5 NTU, and the photocatalyst can be recycled. Aluminum ions are combined with ammonium polyacrylate, so that the purpose of rapid flocculation and sedimentation is achieved; organic matters in the sewage are degraded by adopting a photocatalyst under the irradiation of a xenon lamp, so that secondary pollution caused by the treated and discharged sewage is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a rapid sedimentation ECIS sewage treatment process. Background Art

[0002] In "ECIS," "E" stands for micro-physicochemical, "C" for microcarriers, "I" for micro-electrolysis, and "S" for sequential batching. Sequential batching refers to the entire sewage treatment process, where wastewater is treated in batches according to specific steps. For example, if one treatment cycle is completed in six hours, four batches of sewage can be treated in one day. "ECIS" refers to a method of treating sewage using electrolysis and the addition of microbial carriers.

[0003] A Chinese invention patent, currently published as "CN117303651B," discloses an ECIS (Electrochemical Insulator) four-micro physicochemical membrane small-scale sewage treatment device. The ECIS sewage treatment process comprises six stages: electrolysis, anaerobic biochemical treatment, anoxic biochemical treatment, aerobic biochemical treatment, electroflocculation, and filtration. Sewage typically contains both small solid particles and organic pollutants. Therefore, sewage treatment requires sedimentation of the solid pollutants, followed by electrolysis to break the organic pollutants into small organic and inorganic molecules that attach to microbial carriers. However, due to their small size, the small solid pollutant particles settle slowly, significantly reducing sewage treatment efficiency. Furthermore, organic pollutants are highly toxic, and breaking the bonds easily generates new waste, causing secondary pollution. Summary of the Invention

[0004] The purpose of the present invention is to provide a rapid sedimentation ECIS sewage treatment process to solve the problem of how to quickly settle small solid particles and efficiently and safely treat organic pollutants.

[0005] A rapid sedimentation ECIS wastewater treatment process comprises the following steps:

[0006] S1: Electrolysis stage: The sewage is passed into a treatment tank with an electrode assembly for electrolysis. The electrode assembly includes aluminum electrodes and iron electrodes arranged parallel to each other and spaced apart. Aerobic sludge granules (AGS) are added to the treatment tank. The aerobic sludge granules (AGS) are cultivated with anaerobic ammonium oxidizing bacteria.

[0007] S2: Anaerobic stage in biochemical treatment: After the sewage is electrolyzed, the water flow is stopped and the sewage in the treatment tank is left to stand, where some sediment settles;

[0008] S3: Anoxic stage in biochemical treatment: The aeration fan at the bottom of the treatment tank is turned on and operates in a 5-minute on and 10-minute off mode. With each aeration, the dissolved oxygen content in the sewage increases, and the dissolved oxygen content gradually decreases during the aeration interval. This anoxic stage lasts for 1 hour.

[0009] S4: Aerobic stage in biochemical treatment: Aeration allows the microbial carriers in the water to fully contact with oxygen, and the aerobic stage lasts for 120 minutes;

[0010] S5: Flocculation and sedimentation stage: After the aerobic stage is completed, the aeration fan is turned off, and polyacrylate ammonium flocculant and photocatalyst are added to the treatment tank. The xenon lamp is turned on to irradiate the sewage in the treatment tank. The polyacrylate ammonium adsorbs pollutants in the water and flocculates and precipitates into large particles of sludge. The photocatalyst degrades organic matter under the irradiation of the xenon lamp. After the flocculation and degradation are completed, the sewage is allowed to stand and settle into large particles of sludge.

[0011] S6: Filtration stage: After settling in the treatment tank, the sewage with large particles of sludge is passed into the filter tank. The filter components in the filter tank filter the sewage. The filter components filter the large particles of sludge and discharge them from the bottom of the filter tank. The clean water is discharged from the side of the filter tank to the clean water drain pipe, and then passes through the tubular ultraviolet sterilizer to complete the entire sewage treatment process.

[0012] The beneficial effects of the above technical solution are:

[0013] 1. The use of anaerobic ammonium oxidizing bacteria to cultivate aerobic sludge particles (AGS) has low energy consumption, can save oxygen supply energy consumption and save costs;

[0014] 2. Aluminum electrode electrolysis produces aluminum ions, which are cations, and bacteria produced by sewage electrolysis are anions. Aluminum ions can generate bridges to strengthen the connection between particles in sewage, prompting them to aggregate to form larger flocs, and then use polyacrylate ammonium flocculant for flocculation. Polyacrylate ammonium has high molecular weight and solid content, with a molecular weight of 2.11 million and a solid content of 33.29%. The emulsion flocculant has good stability and water solubility, and has good flocculation performance for red mud. The sedimentation rate can reach 5.8 mL / s, and the turbidity of the supernatant is 105.5 NTU. The combination of aluminum ions and polyacrylate ammonium achieves the purpose of rapid flocculation and sedimentation; a photocatalyst is used to degrade organic matter in sewage under the irradiation of a xenon lamp to avoid secondary pollution caused by the sewage discharged after treatment.

[0015] Preferred solution 1: As a further optimization of the basic solution, an overflow trough is provided on the side wall of the treatment tank, and a filter screen is provided between the overflow trough and the treatment tank.

[0016] The clear liquid at the top of the treatment tank is retained in the overflow tank, which shortens the hydraulic retention time in the sedimentation process, reduces sludge expansion, and thus accelerates the sedimentation rate.

[0017] Preferred Option 2: As a further optimization of Preferred Option 1, a reflux pump is provided on the side of the treatment pool, the water inlet end of the reflux pump is connected to the bottom of the treatment pool through a pipe, and the water outlet end of the reflux pump is connected to the middle of the treatment pool through a pipe.

[0018] The operation of the reflux pump can make the sludge in the treatment pool float up, so that the microorganisms in the sludge can fully contact with the oxygen-containing sewage, thereby improving the sewage treatment efficiency.

[0019] Preferred solution three: As a further optimization of preferred solution two, the synthesis steps of ammonium polyacrylate in step S5 are as follows:

[0020] Step 1: Preparation of water phase:

[0021] (1) Preparation of ammonium acrylate monomer: Weigh a certain amount of acrylic acid and ammonia water respectively, add the ammonia water dropwise to the acrylic acid while stirring continuously (the entire dropwise addition process is carried out in an ice-water bath, and the system temperature is maintained at no more than 40°C). After the ammonia water is added, continue stirring in the ice-water bath for 10 minutes before use;

[0022] (2) adding the weighed disodium ethylenediaminetetraacetate (EDTA-2Na) to the freshly prepared ammonium acrylate solution in (1) and stirring on a magnetic stirrer for 30 minutes to obtain an aqueous phase;

[0023] Step 2: Preparation of oil phase:

[0024] Weigh a certain amount of white oil into a beaker, add Span80 / Tween80 compound emulsifier, and mix well with a magnetic stirrer to obtain an oil phase;

[0025] Step 3: Emulsion polymerization:

[0026] (1) Emulsification: The oil phase and the water phase were mixed and emulsified using a shear emulsifier. The mixture was then transferred to a four-necked flask, connected to a reaction apparatus, set the speed to 500 r / min, and stirred while passing nitrogen for 10 min. The desired water bath temperature was then set as required.

[0027] (2) Polymerization: Weigh APS and NaHSO; composite initiator, dissolve them in a small amount of water and transfer them to the dropping funnel respectively. Insert a nitrogen tube at the same time and add the initiator dropwise while passing nitrogen (control the addition within half an hour). After the initiator is finished, continue to pass nitrogen for a while, set the required temperature and react for 6 to 8 hours to finally obtain a light yellow translucent latex product, which is the ammonium polyacrylate flocculant.

[0028] Preferred Scheme 4: As a further optimization of Preferred Scheme 3, the photocatalyst of step S5 is a double-layer hollow C / TiO2 microsphere photocatalyst. The preparation of this catalyst is to take sulfuric acid solutions with concentrations of 85wt%, 75wt%, 65wt%, and 50wt%, respectively, and take a certain amount of polyacrylonitrile thermal expansion microspheres to the above-mentioned sulfuric acid solution, and hydrolyze at 60°C for 20 minutes, wash with water to neutrality, and then replace water with a large amount of ethanol, soak in a mixed solution of tetrabutyl titanate and ethanol with a ratio of 1:1 for 8 hours, and then place it in a mixed solution of water and ethanol with a ratio of 1:1 and soak for 1 hour, centrifuge, dry, and calcine at 450°C for 2 hours under nitrogen protection to obtain C / TiO2 composite microspheres.

[0029] Preferred solution five: As a further optimization of preferred solution four, the filter assembly in the filter pool in step S6 includes a stirring shaft suspended in the center of the filter pool, a spiral stirring blade is provided at the lower part of the stirring shaft, the top of the filter pool is covered with a cover plate, the top of the stirring shaft extends out of the cover plate, and the end of the stirring shaft extending out of the cover plate is fixedly connected to a motor, and the motor can control the rotation speed of the rotating shaft at 80-120r / min. A water inlet is provided at the upper part of the filter pool, a water outlet is provided at the upper part of the filter pool, a sewage outlet is provided at the bottom of the filter pool, the sewage outlet is lower than the height of the bottom of the filter pool, and both the water outlet and the sewage outlet are provided with electric valves.

[0030] Sewage containing large particles of sludge enters the filter tank through the water inlet, the motor is started and the stirring shaft is controlled to rotate, the stirring blades stir to generate centrifugal force, and under the action of centrifugal force, the large particles of sludge in the sewage gather to the central bottom of the filter tank, and the clean water gathers to the outside of the filter tank, thereby achieving the sewage separation effect. The separated clean water flows out of the filter tank through the water outlet, and the separated sludge particles are discharged from the filter tank through the sewage outlet. The centrifugal force generated by the spiral stirring blades with a rotation speed of 80-120r / min will not destroy the large particles of sludge. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the process flow of an embodiment of the present invention;

[0032] Figure 2 It is a schematic diagram of the local structure of the treatment pool;

[0033] Figure 3 Schematic diagram of the cross-sectional structure of the filter tank;

[0034] The reference numerals in the drawings of the specification include: treatment tank 1, overflow tank 2, filter screen 3, filter tank 4, stirring shaft 5, spiral stirring blade 6, cover plate 7, motor 8, water inlet 9, water outlet 10, and sewage outlet 11. DETAILED DESCRIPTION

[0035] The following is further described in detail through specific implementation methods:

[0036] The embodiment is basically as shown in the attached Figure 1-3 As shown:

[0037] Treatment pool 1, such as Figure 2 As shown, an overflow trough 2 is provided on the side wall of the treatment pool 1 , and a filter screen 3 is provided between the overflow trough 2 and the treatment pool 1 .

[0038] Filter tank 4, such as Figure 3 As shown, a filter assembly is provided in the filter pool 4, and the filter assembly includes a stirring shaft 5 suspended in the center of the filter pool 4, a spiral stirring blade 6 is provided at the lower part of the stirring shaft 5, the top of the filter pool 4 is covered with a cover plate 7, the top end of the stirring shaft 5 extends out of the cover plate 7, and the end of the stirring shaft 5 extending out of the cover plate 7 is fixedly connected to a motor 8, and the motor 8 can control the rotation speed of the rotating shaft at 80-120r / min, a water inlet 9 is provided at the upper part of the filter pool 4, a water outlet 10 is provided at the upper part of the filter pool 4, a sewage outlet 11 is provided at the bottom of the filter pool 4, and the sewage outlet 11 is lower than the height of the bottom of the filter pool 4, and the water outlet 10 and the sewage outlet 11 are both provided with electric valves.

[0039] The synthesis steps of ammonium polyacrylate are as follows:

[0040] Step 1: Preparation of water phase:

[0041] (1) Preparation of ammonium acrylate monomer: Weigh a certain amount of acrylic acid and ammonia water respectively, add the ammonia water dropwise to the acrylic acid while stirring continuously (the entire dropwise addition process is carried out in an ice-water bath, and the system temperature is maintained at no more than 40°C). After the ammonia water is added, continue stirring in the ice-water bath for 10 minutes before use;

[0042] (2) adding the weighed disodium ethylenediaminetetraacetate (EDTA-2Na) to the freshly prepared ammonium acrylate solution in (1) and stirring on a magnetic stirrer for 30 minutes to obtain an aqueous phase;

[0043] Step 2: Preparation of oil phase:

[0044] Weigh a certain amount of white oil into a beaker, add Span80 / Tween80 compound emulsifier, and mix well with a magnetic stirrer to obtain an oil phase;

[0045] Step 3: Emulsion polymerization:

[0046] (1) Emulsification: The oil phase and the water phase were mixed and emulsified using a shear emulsifier. The mixture was then transferred to a four-necked flask, connected to a reaction apparatus, set the speed to 500 r / min, and stirred while passing nitrogen for 10 min. The desired water bath temperature was then set as required.

[0047] (2) Polymerization: Weigh APS and NaHSO; composite initiator, dissolve them in a small amount of water and transfer them to the dropping funnel respectively. Insert a nitrogen tube at the same time and add the initiator dropwise while passing nitrogen (control the addition within half an hour). After the initiator is finished, continue to pass nitrogen for a while, set the required temperature and react for 6 to 8 hours to finally obtain a light yellow translucent latex product, which is the ammonium polyacrylate flocculant.

[0048] The preparation method of double-layer hollow C / TiO2 microsphere photocatalyst is as follows:

[0049] Sulfuric acid solutions with concentrations of 85wt%, 75wt%, 65wt% and 50wt% were prepared respectively, and a certain amount of polyacrylonitrile thermal expansion microspheres were added to the above sulfuric acid solutions, and hydrolyzed at 60°C for 20 minutes, washed with water until neutral, and then replaced with a large amount of ethanol instead of water, immersed in a mixed solution of tetrabutyl titanate and ethanol in a ratio of 1:1 for 8 hours, and then immersed in a mixed solution of water and ethanol in a ratio of 1:1 for 1 hour, centrifuged, dried, and calcined at 450°C for 2 hours under nitrogen protection to obtain C / TiO2 composite microspheres.

[0050] The specific implementation process is as follows:

[0051] A rapid sedimentation ECIS wastewater treatment process, such as Figure 1 As shown, the following steps are included:

[0052] S1: Electrolysis stage: The sewage is passed into a treatment tank with an electrode assembly for electrolysis. The electrode assembly includes aluminum electrodes and iron electrodes arranged parallel to each other and spaced apart. Aerobic sludge granules (AGS) are added to the treatment tank. The aerobic sludge granules (AGS) are cultivated with anaerobic ammonium oxidizing bacteria.

[0053] S2: Anaerobic stage in biochemical treatment: After the sewage is electrolyzed, the water flow is stopped and the sewage in the treatment tank is left to stand, where some sediment settles;

[0054] S3: Anoxic stage in biochemical treatment: The aeration fan at the bottom of the treatment tank is turned on and operates in a 5-minute on and 10-minute off mode. With each aeration, the dissolved oxygen content in the sewage increases, and the dissolved oxygen content gradually decreases during the aeration interval. This anoxic stage lasts for 1 hour.

[0055] S4: Aerobic stage in biochemical treatment: Aeration allows the microbial carriers in the water to fully contact with oxygen, and the aerobic stage lasts for 120 minutes;

[0056] S5: Flocculation and sedimentation stage: After the aerobic stage is completed, the aeration fan is turned off, and polyacrylate ammonium flocculant and photocatalyst are added to the treatment tank. The xenon lamp is turned on to irradiate the sewage in the treatment tank. The polyacrylate ammonium adsorbs pollutants in the water and flocculates and precipitates into large particles of sludge. The photocatalyst degrades organic matter under the irradiation of the xenon lamp. After the flocculation and degradation are completed, the sewage is allowed to stand and settle into large particles of sludge.

[0057] S6: Filtration stage: After settling in the treatment tank, the sewage with large particles of sludge is passed into the filter tank, the motor is started and the stirring shaft is controlled to rotate. The stirring shaft speed is 100r / min. The stirring blades stir to generate centrifugal force. Under the action of centrifugal force, the large particles of sludge in the sewage gather to the bottom of the center of the filter tank, and the clean water gathers to the outside of the filter tank, achieving the effect of separating the sewage. The separated clean water flows out of the filter tank through the outlet, and the separated sludge particles are discharged out of the filter tank through the sewage outlet. The clean water is led out of the outlet to the clean water pipe, and then passes through the tubular ultraviolet sterilizer to complete the entire sewage treatment process.

[0058] Ammonium polyacrylate flocculant is used for flocculation. The molecular weight and solid content of ammonium polyacrylate are both very high, with a molecular weight of 2.11 million and a solid content of 33.29%. The emulsion flocculant has good stability and water solubility, and has excellent flocculation performance on red mud. It can accelerate the sedimentation rate, which can reach 5.8mL / s, and the turbidity of the supernatant is 105.5NTU. A photocatalyst is used to degrade organic matter in the sewage under the irradiation of a xenon lamp to avoid secondary pollution caused by the discharged sewage after treatment.

[0059] The above is only an embodiment of the present invention, and the common knowledge such as the specific structure and characteristics of the scheme is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A rapid sedimentation ECIS wastewater treatment process, characterized in that: The following steps are included: S1: Electrolysis stage: The sewage is passed into a treatment tank with an electrode assembly for electrolysis. The electrode assembly includes aluminum electrodes and iron electrodes arranged parallel to each other and spaced apart. Aerobic sludge granules (AGS) are added to the treatment tank. The aerobic sludge granules (AGS) are cultivated with anaerobic ammonium oxidizing bacteria. S2: Anaerobic stage in biochemical treatment: After the sewage is electrolyzed, the water flow is stopped and the sewage in the treatment tank is left to stand, where some sediment settles; S3: Anoxic stage in biochemical treatment: The aeration fan at the bottom of the treatment tank is turned on and operates in a 5-minute on and 10-minute off mode. With each aeration, the dissolved oxygen content in the sewage increases, and the dissolved oxygen content gradually decreases during the aeration interval. This anoxic stage lasts for 1 hour. S4: Aerobic stage in biochemical treatment: Aeration allows the microbial carriers in the water to fully contact with oxygen, and the aerobic stage lasts for 120 minutes; S5: Flocculation and sedimentation stage: After the aerobic stage is completed, the aeration fan is turned off, and polyacrylate ammonium flocculant and photocatalyst are added to the treatment tank. The xenon lamp is turned on to irradiate the sewage in the treatment tank. The polyacrylate ammonium adsorbs pollutants in the water and flocculates and precipitates into large particles of sludge. The photocatalyst degrades organic matter under the irradiation of the xenon lamp. After the flocculation and degradation are completed, the sewage is allowed to stand and settle into large particles of sludge. S6: Filtration stage: After settling in the treatment tank, the sewage with large particles of sludge is passed into the filter tank. The filter components in the filter tank filter the sewage. The filter components filter the large particles of sludge and discharge them from the bottom of the filter tank. The clean water is discharged from the side of the filter tank to the clean water drain pipe, and then passes through the tubular ultraviolet sterilizer to complete the entire sewage treatment process.

2. A rapid sedimentation ECIS sewage treatment process according to claim 1, characterized in that: An overflow trough is provided in the middle of the treatment pool, and a filter screen is provided between the overflow trough and the treatment pool.

3. The rapid sedimentation ECIS sewage treatment process according to claim 1, characterized in that: A reflux pump is provided on the side of the treatment pool. The water inlet end of the reflux pump is connected to the bottom of the treatment pool through a pipeline, and the water outlet end of the reflux pump is connected to the middle of the treatment pool through a pipeline.

4. The rapid sedimentation ECIS sewage treatment process according to claim 1, characterized in that: The synthesis steps of the ammonium polyacrylate in step S5 are as follows: Step 1: Preparation of water phase: (1) Preparation of ammonium acrylate monomer: Weigh a certain amount of acrylic acid and ammonia water respectively, add the ammonia water dropwise to the acrylic acid while stirring continuously (the entire dropwise addition process is carried out in an ice-water bath, and the system temperature is maintained at no more than 40°C). After the ammonia water is added, continue stirring in the ice-water bath for 10 minutes before use; (2) adding the weighed disodium ethylenediaminetetraacetate (EDTA-2Na) to the freshly prepared ammonium acrylate solution in (1) and stirring on a magnetic stirrer for 30 minutes to obtain an aqueous phase; Step 2: Preparation of oil phase: Weigh a certain amount of white oil into a beaker, add Span80 / Tween80 compound emulsifier, and mix well with a magnetic stirrer to obtain an oil phase; Step 3: Emulsion polymerization: (1) Emulsification: The oil phase and the water phase were mixed and emulsified using a shear emulsifier. The mixture was then transferred to a four-necked flask, connected to a reaction apparatus, set the speed to 500 r / min, and stirred while passing nitrogen for 10 min. The desired water bath temperature was then set as required. (2) Polymerization: Weigh APS and NaHSO; composite initiator, dissolve them in a small amount of water and transfer them to the dropping funnel respectively. Insert a nitrogen tube at the same time and add the initiator dropwise while passing nitrogen (control the addition within half an hour). After the initiator is finished, continue to pass nitrogen for a while, set the required temperature and react for 6 to 8 hours to finally obtain a light yellow translucent latex product, which is the ammonium polyacrylate flocculant.

5. The rapid sedimentation ECIS sewage treatment process according to claim 1, characterized in that: The photocatalyst of step S5 is a double-layer hollow C / TiO2 microsphere photocatalyst. The catalyst is prepared by taking sulfuric acid solutions with concentrations of 85wt%, 75wt%, 65wt%, and 50wt%, respectively, taking a certain amount of polyacrylonitrile thermal expansion microspheres and adding them to the above sulfuric acid solutions, and hydrolyzing them at 60°C for 20 minutes, washing them with water until neutral, and then replacing water with a large amount of ethanol, soaking them in a mixed solution of tetrabutyl titanate and ethanol with a ratio of 1:1 for 8 hours, and then soaking them in a mixed solution of water and ethanol with a ratio of 1:1 for 1 hour, centrifuging, drying, and calcining them at 450°C for 2 hours under nitrogen protection to obtain C / TiO2 composite microspheres.

6. The rapid sedimentation ECIS sewage treatment process according to claim 1, characterized in that: The filter assembly in the filter pool in step S6 includes a stirring shaft suspended in the center of the filter pool, a spiral stirring blade is provided at the lower part of the stirring shaft, the top of the filter pool is covered with a cover plate, the top of the stirring shaft extends out of the cover plate, and the end of the stirring shaft extending out of the cover plate is fixedly connected to a motor, and the motor can control the rotation speed of the rotating shaft to 80-120r / min. A water inlet is provided at the upper part of the filter pool, a water outlet is provided at the upper part of the filter pool, and a sewage outlet is provided at the bottom of the filter pool, the sewage outlet is lower than the height of the bottom of the filter pool, and the water outlet and the sewage outlet are both provided with electric valves.

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