Deep denitrification device for wastewater in electronic industrial park

Abstract

The utility model discloses a deep denitrification device for wastewater in an electronic industrial park, which comprises a reactor, a filler area is arranged in the reactor, and the filler area is formed by sequentially and alternately arranging sulfur filler layers and zero-valent iron filler layers; a bearing area is arranged below the filling area; a cylindrical graphite anode penetrating through the filler area is also arranged in the reactor; the stainless steel side wall of the reactor serves as a cathode, and the cathode and the anode are connected with an external power source through wires respectively. According to the deep denitrification device disclosed by the utility model, denitrification is carried out in a sulfur-iron-hydrogen autotrophic denitrification synergistic manner, so that the problems that the effluent is slightly acidic and slightly alkaline and the content of sulfate radicals in the effluent is high can be solved, and the denitrification reaction rate of microbial strains can be effectively improved.

Description

Technical Field

[0001] The utility model relates to a device for deep denitrification of wastewater in an electronic industrial park based on autotrophic denitrification. Background Art

[0002] Since the 21st century, with the continuous improvement of China's industrial level, the scale and number of domestic electronic industrial parks have gradually increased, and the deep treatment and reuse of industrial park wastewater has received increasing attention. At present, the country's discharge standards for sewage treatment plants have been gradually improved, and the discharge standards of more and more industrial park sewage treatment plants and municipal sewage treatment plants have been upgraded from the original "Urban Sewage Treatment Plant Pollutant Discharge Standard" GB18918-2002 to Class A or higher standards.

[0003] Taking the first-level A standard as an example, the TN requirement for effluent is less than 15 mg / L. The discharge standards for industrial parks and municipal wastewater in some areas have required TN ≤ 10 mg / L. Currently, the A standard is usually used. 2 O+ denitrification filter is the main biological method to remove total nitrogen. Since the carbon and nitrogen ratio of the wastewater in the electronic industrial park is relatively low, traditional heterotrophic denitrification requires the addition of a large amount of organic carbon source such as sodium acetate, which not only increases the cost of the reagents, but also increases the risk of carbon source penetration leading to excessive COD in the effluent. Autotrophic denitrification has the advantages of no need to add organic carbon sources, low sludge production, and low operating costs, and is widely studied in the field of deep nitrogen removal. Sulfur autotrophic denitrification is a process that uses reduced sulfur substances (such as S, S) under anoxic or anaerobic conditions. 2- 、S2O3 2- ) as an electron donor to convert nitrate nitrogen or nitrite nitrogen into nitrogen gas. No organic carbon source is required during the reaction, but it has the disadvantages of acid production and high sulfate content. Iron autotrophic denitrifying bacteria are also a type of bacteria that can use nitrate nitrogen as an electron acceptor, elemental iron or various forms of Fe 2+ compounds as electron donors, but alkalinity will be generated during the denitrification process, which will increase the pH of the effluent and produce Fe 2+ , Fe 3+ Chemical association and OH - Combined with, and then the filler surface scale passivation, affecting the denitrification effect. Studies have found that in the sulfur autotrophic denitrification system, adding elemental iron or iron compounds, iron autotrophic denitrification will share part of the nitrate nitrogen load of the sulfur autotrophic denitrification process, thereby making the effluent SO4 2- The concentration of SO4 in the effluent of sulfur autotrophic denitrification is higher than that of 2- The concentration is greatly reduced, and at the same time, iron autotrophic denitrification will produce alkalinity, which can slow down the decrease in pH value of the sulfur autotrophic denitrification system. Utility Model Content

[0004] Purpose of the utility model: The purpose of the utility model is to provide a deep denitrification device for wastewater in an electronic industrial park. The device adopts a sulfur-iron-hydrogen autotrophic denitrification synergistic method to denitrify, which can not only solve the problems of acidic and alkaline effluent and high sulfate content in effluent, but also effectively improve the denitrification reaction rate of microbial strains.

[0005] Technical solution: The deep denitrification device for wastewater in an electronic industrial park described in the utility model includes a reactor, wherein a packing area is provided in the reactor, wherein the packing area is composed of sulfur packing layers and zero-valent iron packing layers arranged alternately in sequence; a supporting area is provided below the packing area; a cylindrical graphite anode penetrating the packing area is also provided in the reactor; the stainless steel side wall of the reactor serves as a cathode, and the cathode and the anode are respectively connected to an external power supply through wires.

[0006] Wherein, a water inlet and an air inlet are arranged at the bottom of the reactor; an exhaust port, a water production port, a reflux port and a backwash water outlet are arranged at the top of the reactor.

[0007] It also includes a wastewater collection tank, a pH adjustment tank, a water production tank and a fan; a quartz sand filter is provided on the connecting pipe between the wastewater collection tank and the pH adjustment tank; the effluent from the pH adjustment tank enters the reactor through the water inlet, and after being processed in the reactor, the produced water enters the water production tank through the water production port, and part of the reflux water flows back to the pH adjustment tank through the reflux port; during the backwashing process, the water from the water production tank enters the reactor through the water inlet, and the fan is connected to the air inlet of the reactor.

[0008] Among them, a water distribution pipe and an air distribution pipe connected to the water inlet and the air inlet are provided at the bottom of the reactor, and the water distribution pipe includes a water distribution main pipe and four H-shaped water distribution branches; one end of the water distribution main pipe is connected to the water inlet, and the other end is divided into two branches, each branch is respectively connected to two H-shaped water distribution branches, and the water outlet of the water distribution branch pipe is parallel to the radial direction of the reactor.

[0009] Among them, the air distribution pipe is located on the side of the water distribution pipe close to the supporting area; the air distribution pipe includes an air distribution main pipe and multiple air distribution branch pipes; one end of the air distribution main pipe is connected to the air inlet, and the other end is divided into multiple branches; each air distribution pipe is provided with multiple holes with a diameter of 3 to 6 mm, the spacing between adjacent holes is 120 to 150 mm, and the angle between the direction of the hole and the horizontal plane is 45° or 135°.

[0010] Wherein, the supporting area uses a porous filter plate as a supporting layer, and a pebble layer is arranged on the supporting layer.

[0011] Wherein, a porous filter plate support layer is arranged under each sulfur filler layer and each zero-valent iron filler layer.

[0012] Beneficial effects: Compared with the prior art, the utility model has the following advantages: (1) The utility model reactor can solve the problem of excessively acidic or alkaline pH during the reaction process of sulfur autotrophic and iron autotrophic single autotrophic denitrification by alternately filling sulfur fillers and iron fillers, which affects the denitrification efficiency of autotrophic bacteria and further affects the effluent water quality. The utility model reactor can maintain the relative stability of the pH of the water body inside the reactor, ensure the denitrification efficiency of the microbial strains, and at the same time reduce the sulfate content of the effluent and reduce secondary pollution of the water body; (2) The utility model reactor can also realize hydrogen production by electrolysis, thereby continuously providing hydrogen for autotrophic denitrification, avoiding the problem of low efficiency and high cost of exogenous hydrogen supply (directly providing hydrogen source), and at the same time using sulfur, iron and hydrogen to synergistically carry out autotrophic denitrification, greatly improving the denitrification rate; and the electrolysis method generates heat, which increases the water temperature, maintains the functional enzyme activity in the autotrophic denitrifying bacteria group under the external low temperature environment, and ensures the denitrification efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the system principle diagram of the deep denitrification device of the utility model;

[0014] Figure 2 It is a schematic diagram of the structure of the reactor;

[0015] Figure 3 It is a schematic diagram of the structure of the reactor cylinder;

[0016] Figure 4 It is a schematic diagram of the structure of the water distribution pipe;

[0017] Figure 5 It is a structural schematic diagram of the air distribution pipe;

[0018] Figure 6 Schematic diagram of the structure of a porous filter plate. DETAILED DESCRIPTION

[0019] like Figures 1 to 6As shown, the deep denitrification device for electronic industrial park wastewater of the utility model comprises a reactor 1, wherein a packing area 2 is arranged in the reactor 1, wherein the packing area 2 is composed of sulfur packing layers 21 and zero-valent iron packing layers 22 arranged alternately in sequence, and provides electrons for sulfur and iron autotrophic denitrifying bacteria to convert nitrate nitrogen into nitrogen gas; a supporting area 3 is arranged below the packing area 2; a cylindrical graphite anode 4 penetrating the packing area 2 is also arranged in the reactor 1; the stainless steel side wall of the reactor 1 serves as a cathode, and the cathode and the anode are respectively connected to an external power supply through a wire; under the condition of power on (voltage 0 .25~0.5V, current 20~50mA) hydrogen will be generated on the cathode surface, providing a source of hydrogen for hydrogen autotrophic denitrifying bacteria. Under the action of water flushing, hydrogen is mixed in the water body and fully contacts with the wastewater, further improving the autotrophic denitrification rate. In addition, powering on will cause the water body to heat up, increase the water temperature, improve the functional enzyme activity in the autotrophic denitrifying bacteria community, and increase the nitrate nitrogen removal rate; the bottom of the reactor 1 is provided with a water inlet 11 and an air inlet 12; the top of the reactor is provided with an exhaust port 13, a water production port 14, a reflux port 15 and a backwash water outlet 16.

[0020] The deep denitrification device of the utility model also includes a wastewater collection tank 5, a pH adjustment tank 6, a water production tank 7 and a fan 8; a quartz sand filter 9 is provided on the connecting pipe between the wastewater collection tank 5 and the pH adjustment tank 6; the effluent of the pH adjustment tank 6 enters the reactor 1 through the water inlet 11, and after being processed in the reactor 1, the produced water enters the water production tank 7 through the water production port 14, and part of the reflux water flows back to the pH adjustment tank 6 through the reflux port 15; during the backwashing process, the water of the water production tank 7 enters the reactor 1 through the water inlet 11, and the fan 8 is connected to the air inlet 12 of the reactor. The backwashing order is air washing, air-water combined washing, and water washing, and the backwashing water and air intake are both entered from the water inlet 11 and the air inlet 12 at the bottom of the reactor 1. The backwashing water is the produced water of the reactor 1, which is transported from the water production tank 7 to the bottom of the reactor 1 by the backwashing water pump for backwashing, and the air for backwashing is provided by the fan 8.

[0021] Among them, a water distribution pipe 17 and an air distribution pipe 18 are provided at the bottom of the reactor 1, which are correspondingly connected to the water inlet 11 and the air inlet 12. The water distribution pipe 17 includes a water distribution main pipe 19 and four H-shaped water distribution branches 20; one end of the water distribution main pipe 19 is connected to the water inlet 11, and the other end is divided into two branches, each branch is connected to two H-shaped water distribution branches 20, and the H-shaped water distribution branch can ensure that the water quality of the inlet water is more evenly distributed; the outlet of the water distribution branch pipe 20 is parallel to the radial direction of the reactor 1. The air distribution pipe 18 is located on the side of the water distribution pipe 17 close to the supporting area 3; the air distribution pipe 18 includes an air distribution main pipe and multiple air distribution branches; the purpose of air distribution is to regularly backwash the filler with air to prevent the filler from being accumulated for a long time to cause scaling or hardening and to carry away the nitrogen between the fillers by air washing. The air distribution pipe is a tubular aeration, one end of the air distribution main pipe is connected to the air inlet, and the other end is divided into multiple branches; each air distribution pipe is provided with multiple holes with a diameter of 3 to 6 mm, the distance between adjacent holes is 120 to 150 mm, and the angle between the direction of the hole and the horizontal plane is 45° or 135°.

[0022] The supporting area 3 has a porous filter plate 31 as a supporting layer. The aperture of the holes on the porous filter plate 31 is 4 mm, the spacing between adjacent holes is 2 mm, and the thickness of the porous filter plate 31 is 100 mm. A pebble layer 32 is provided on the supporting layer. In the pebble layer 32, the particle sizes of the pebbles from top to bottom are 4 to 8, 8 to 16, and 16 to 32 mm, respectively, and the filling height of the pebble layer 32 is 300 to 360 mm. A porous filter plate 31 is provided as a supporting layer below each sulfur filler layer 21 and each zero-valent iron filler layer 22, and the porous filter plate 31 is used to support the filler. In the packing area 2, the distance between adjacent porous filter plates 31 is 0.5 to 0.7 meters, and different types of packing are filled in between. Sulfur packing and zero-valent iron packing are filled alternately in order to keep the pH of the reactor water relatively stable during the reaction process and prevent excessive acidity and alkalinity from inhibiting the denitrification rate. A packing filling port is set on the top of each layer of packing in the reactor, so that it is convenient to replenish the packing from the filling port when the packing is consumed. Above the packing area 2 is an ultra-high area with a height of 1.2 to 1.5 meters.

[0023] Wastewater from an electronics industrial park 10000m 3 / d, the inlet nitrate nitrogen concentration is 30 mg / L, the pH is 6.5-7.5, and the outlet nitrate nitrogen is required to be less than 10 mg / L; the utility model device is used to denitrify the above wastewater, specifically:

[0024] Step 1: The wastewater from the electronic park is transported from the wastewater collection tank 5 to the quartz sand filter 9 (to remove suspended impurities in the wastewater) by a lifting pump, flows into the top of the quartz sand filter 9, and flows out from the bottom to the pH adjustment tank 6.

[0025] Step 2: Add liquid medicine into the pH adjustment tank 6 through sulfuric acid and liquid alkali dosing pumps to control the pH of the wastewater to 7.5-8.0, and stir the reaction time for 25 minutes.

[0026] Step 3: The effluent from the pH adjustment tank 6 is pumped into 5 autotrophic denitrification reactors 1 by a delivery pump. The diameter of the reactor 1 is 4.8m and the total height is 10m, wherein the height of the water and gas distribution area is 1.4m, the pebble layer filling height is 0.3m, the denitrification filler filling height is 7m (a total of 10 layers of sulfur filler and iron filler, the fillers are arranged alternately), the super-high height is 1.2m, and the effluent enters the water production tank 7. The reflux rate of the reactor 1 is controlled to be 100% (part of the produced water goes to the water production tank 7, and part is transported to the pH adjustment tank 6 through the reflux pump), the voltage is 4.5V, the current is 40mA, and the hydraulic retention time is 1.5h; after treatment, the nitrate nitrogen concentration of the reactor effluent is 8.5mg / L.

[0027] Step 4: After the autotrophic denitrification reactor 1 has been running for 7 days, it is backwashed in sequence. The fan 8 is started for air washing, and the backwashing water pump is started for air-water combined washing and water washing. The backwashing water enters the park wastewater collection pool 5; the air washing time of the reactor 1 is controlled to be 3 minutes, the air-water combined washing time is 5 minutes, the water washing time is 5 minutes, and the air washing intensity is 20L / (m 2 .s), water flushing intensity is 5L / (m 2 .s).

Claims

1. A deep denitrification device for wastewater in an electronic industrial park, characterized by: The invention comprises a reactor, wherein a packing area is arranged in the reactor, wherein the packing area is composed of sulfur packing layers and zero-valent iron packing layers arranged alternately in sequence; a supporting area is arranged below the packing area; a cylindrical graphite anode penetrating the packing area is also arranged in the reactor; the stainless steel side wall of the reactor serves as a cathode, and the cathode and the anode are respectively connected to an external power supply through wires.

2. The deep denitrification device for electronic industrial park wastewater according to claim 1 is characterized in that: The bottom of the reactor is provided with a water inlet and an air inlet; the top of the reactor is provided with an exhaust port, a water production port, a reflux port and a backwash water outlet.

3. The deep denitrification device for electronic industrial park wastewater according to claim 2 is characterized in that: It also includes a wastewater collection tank, a pH adjustment tank, a water production tank and a fan; a quartz sand filter is provided on the connecting pipe between the wastewater collection tank and the pH adjustment tank; the effluent from the pH adjustment tank enters the reactor through the water inlet, and after being processed in the reactor, the produced water enters the water production tank through the water production port, and part of the reflux water flows back to the pH adjustment tank through the reflux port; during the backwashing process, the water from the water production tank enters the reactor through the water inlet, and the fan is connected to the air inlet of the reactor.

4. The deep denitrification device for electronic industrial park wastewater according to claim 2 is characterized in that: The bottom of the reactor is provided with a water distribution pipe and an air distribution pipe connected to the water inlet and the air inlet respectively, and the water distribution pipe includes a water distribution main pipe and four H-shaped water distribution branches; one end of the water distribution main pipe is connected to the water inlet, and the other end is divided into two branches, each branch is respectively connected to two H-shaped water distribution branches, and the water outlet of the water distribution branch pipe is parallel to the radial direction of the reactor.

5. The deep denitrification device for wastewater in an electronic industrial park according to claim 4 is characterized in that: The air distribution pipe is located on the side of the water distribution pipe close to the supporting area; the air distribution pipe includes an air distribution main pipe and multiple air distribution branch pipes; one end of the air distribution main pipe is connected to the air inlet, and the other end is divided into multiple branches; each air distribution pipe is provided with multiple holes with a diameter of 3 to 6 mm, the spacing between adjacent holes is 120 to 150 mm, and the angle between the direction of the hole and the horizontal plane is 45° or 135°.

6. The deep denitrification device for electronic industrial park wastewater according to claim 1 is characterized by: The supporting area uses a porous filter plate as a supporting layer, and a pebble layer is arranged on the supporting layer.

7. The deep denitrification device for wastewater in an electronic industrial park according to claim 1 is characterized in that: A porous filter plate support layer is provided under each sulfur filler layer and each zero-valent iron filler layer.

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