CN210012638U - Electrochemical ammonia nitrogen digestion device - Google Patents

Abstract

The utility model relates to the field of wastewater treatment, in particular to an electrochemical ammonia nitrogen digestion device which ensures treatment effect along with gradient change of treatment concentration through electrode material change, comprising a first reaction unit, a second reaction unit, a third reaction unit, a fourth reaction unit and a fifth reaction unit, wherein a water inlet is arranged at the bottom of the first reaction unit, the first reaction unit is communicated with the second reaction unit through an overflow plate I, the second reaction unit is communicated with the third reaction unit through a bottom opening, the third reaction unit is communicated with the fourth reaction unit through an overflow plate II, the fourth reaction unit is communicated with the fifth reaction unit through a bottom opening, a cathode I is arranged in the first reaction unit, an anode I is arranged in the second reaction unit, a cathode II is arranged in the third reaction unit, an anode II is arranged in the fourth reaction unit, and a third cathode is arranged in the fifth reaction unit.

Description

Electrochemical ammonia nitrogen digestion device

Technical Field

The utility model relates to a waste water treatment field, in particular to electrochemistry ammonia nitrogen digestion device.

Background

At present, the development of economic society of China is severely restricted by increasingly severe problems of water environment pollution and water resource shortage. The urban sewage is gradually a global consensus as a second water source of the city, and how to realize the deep purification of the sewage is a key link for the urban sewage to become the second water source. In the process of deep purification treatment of sewage, anions such as nitrogen, phosphorus, fluorine, chlorine and the like, organic matters and the like are pollutants which are difficult to treat in water body treatment.

For removing nitrogen, phosphorus and organic matters in sewage, widely applied treatment technologies mainly adopt a biological method and a chemical precipitation method; for anions such as fluorine and chlorine in water, a dilution treatment is a practical method. However, these techniques have various disadvantages in practical applications, such as long hydraulic retention time, large floor area, insufficient treatment depth, generation of a large amount of sludge which is difficult to dispose, poor stability of biological treatment process, addition of carbon source or chemical agent in conventional denitrification process, high cost, complicated operation and management, etc.

In order to overcome the drawbacks of the above technologies, CN1986435A proposes a combined process of electric flocculation and microfiltration, in which an aluminum plate or an iron plate is used as an electrode to electrolyze to generate an aluminum salt or an iron salt, and a larger floc is formed by combining with fluoride ions and organic matters in water, and then the formed floc is filtered and removed in a subsequent microfiltration membrane module, so as to achieve the purpose of removing fluorine and organic matters from drinking water. The process needs to be combined with a microfiltration device to increase the treatment cost, the surface of the electrode is easy to form an oxide film for passivation, the types of pollutants capable of being treated are single, the concentration of target objects in the water body is low, and the electrochemical efficiency is low.

CN101269863A proposes a combined process of electrocoagulation and membrane bioreactor, which uses iron plate or aluminum plate as anode to produce iron ions or aluminum ions by electrolysis, and forms flocs with hydroxyl ions and phosphate ions in sewage, and the organic matter is degraded by microorganisms in the membrane bioreactor to form sludge, and the sludge is filtered by a microfiltration membrane to remove pollutants, thereby achieving the purpose of removing phosphorus and organic matter from sewage. The system has the advantages of low electrochemical efficiency, high treatment cost, generation of a large amount of sludge which is difficult to treat, poor stability of biological treatment and single pollutant treatment type.

CN101549896A proposes a water treatment method for electrochemical nitrogen and phosphorus removal, which adopts graphite and iron plates as electrodes, and alternately changes the processes of electrolytic phosphorus removal and electrolytic nitrogen removal by intermittently changing the polarity of the electrodes, thereby realizing the removal of nitrogen and phosphorus nutritive salts and organic pollutants in wastewater in the same electrolytic tank. However, in urban sewage, the concentration of the inorganic salts is low, the conductivity of the solution is low, the electrolysis efficiency is low, the electrode spacing is large, the energy consumption is large, and the treatment cost is high.

Nitrogen is still a major factor in water eutrophication. After the industrial wastewater is subjected to primary pretreatment and secondary biochemical treatment, the discharged wastewater still contains a large amount of nitrogen, mainly comprising nitrate nitrogen and nitrite nitrogen, and a small amount of ammonia nitrogen and trace organic nitrogen, which are collectively called Total Nitrogen (TN), and the concentration of the total nitrogen is determined by adopting an alkaline potassium persulfate ultraviolet spectrophotometry.

In recent years, China has made a great deal of research and application practices in the aspect of advanced wastewater treatment, such as biofilters, membrane filtration, advanced oxidation and the like, and mainly aims at treating factors such as COD, chromaticity, ammonia nitrogen and the like in biochemical tail water. Regarding Total Nitrogen (TN) removal, the conventional technology is a biological nitrification and denitrification process, in which a denitrification process is performed by supplementing a carbon source (methanol) to secondary biochemical effluent. The process can effectively remove nitrate nitrogen and nitrite nitrogen, but has poor effect on ammonia nitrogen and organic nitrogen, takes long time and needs to add extra carbon source.

The electrochemical technology is a hot point for domestic and foreign research due to its environmental friendliness. In the process of electrochemical treatment of wastewater, ammonia nitrogen and organic nitrogen (including other organic pollutants) lose electrons at the anode to generate oxidation reaction and are converted into nitrogen; nitrate nitrogen and nitrite nitrogen are reduced by electrons at the cathode and converted into nitrogen, thereby realizing the effective removal of total nitrogen and other pollutants in the wastewater.

At present, chinese patent CN201720527475.5 discloses a plunger flow diaphragm electrolysis device for electrochemically removing total nitrogen in wastewater, which comprises a plunger flow diaphragm electrolysis device body, and is characterized in that a plurality of reaction units are arranged in the plunger flow diaphragm electrolysis device body, an anode and a cathode are arranged in each reaction unit, a diaphragm is arranged between the anode and the cathode, each reaction unit is divided into an anode chamber and a cathode chamber by the diaphragm, a water inlet is arranged in the first cathode chamber of the electrolysis device, a water outlet is arranged in the last anode chamber, and the cathode surface and the anode surface of two adjacent reaction units are compounded into a composite electrode.

Although the above design can solve the problem of removing ammonia nitrogen and total nitrogen in certain sewage, the specific electrode and treatment mode need further improvement due to different concentrations of ammonia nitrogen and total nitrogen in each reaction unit, thereby achieving the purposes of shortening treatment time and improving treatment effect.

SUMMERY OF THE UTILITY MODEL

To the problem mentioned in the background art, the utility model aims at providing a through the electrode material change and then realize guaranteeing the electrochemistry ammonia nitrogen digestion unit of treatment effect along with the gradient change of handling concentration.

The above technical purpose of the present invention can be achieved by the following technical solutions: an electrochemical ammonia nitrogen digestion device comprises a first reaction unit, a second reaction unit, a third reaction unit, a fourth reaction unit and a fifth reaction unit, wherein a water inlet is formed in the bottom of the first reaction unit, the first reaction unit is communicated with the second reaction unit through a first overflow plate, the second reaction unit is communicated with the third reaction unit through a bottom opening, the third reaction unit is communicated with the fourth reaction unit through a second overflow plate, the fourth reaction unit is communicated with the fifth reaction unit through a bottom opening, a first cathode is arranged in the first reaction unit, a first anode is arranged in the second reaction unit, a second cathode is arranged in the third reaction unit, a second anode is arranged in the fourth reaction unit, and a third cathode is arranged in the fifth reaction unit; the distance between the first cathode and the first anode is 20-40mm, the distance between the first anode and the second cathode is 20-40mm, the distance between the second anode and the second cathode is 20-30mm, the distance between the second anode and the third cathode is 15-20mm, the first cathode is a titanium alloy electrode plate, the first anode is a titanium-based lead oxide anode plate, the second cathode is a nitrogen-doped nano-diamond cathode plate, the second anode is a boron-doped nano-diamond anode plate, and the third cathode is a titanium alloy electrode plate containing graphite, platinum and gold.

Preferably, the first reaction unit, the second reaction unit, the third reaction unit, the fourth reaction unit and the fifth reaction unit are all detachably connected.

Preferably, the substrates of the nitrogen-doped nano-diamond cathode plate and the boron-doped nano-diamond anode plate are made of p-type Si or Mo, Ta and Ti metal materials, one side of the substrate of the nitrogen-doped nano-diamond cathode facing the boron-doped nano-diamond anode is coated with a layer of nitrogen-doped nano-diamond film, and one side of the substrate of the boron-doped nano-diamond anode facing the boron-doped nano-diamond cathode is coated with a layer of boron-doped nano-diamond film.

Preferably, the first reaction unit, the second reaction unit, the third reaction unit, the fourth reaction unit and the fifth reaction unit are all tank bodies made of polytetrafluoroethylene.

Preferably, the cathode can also be a niobium-based alloy electrode plate containing graphite, platinum and gold.

Preferably, the cathode I, the anode I, the cathode II, the anode II and the cathode III all adopt a honeycomb body formed by combining wave plates.

Preferably, the honeycomb body is formed by a plurality of stainless steel corrugated plates, two sides of each stainless steel corrugated plate are provided with short planes, two end faces of each stainless steel corrugated plate are in the same direction at an angle of 60 +/-10 degrees, adjacent superposed faces are formed by spot welding or insertion and occlusion of bent tongue pieces, and the honeycomb body is naturally placed at an inclined angle of 60 +/-10 degrees.

To sum up, the utility model discloses mainly have following beneficial effect: the utility model discloses an electrochemistry ammonia nitrogen digestion device passes through the cooperation between inert electrode and the positive pole to through the flow of effective control raw water, thereby promoted the decomposition of ammonia nitrogen and total nitrogen in the raw water, the unique structural design of every plate electrode makes all improve greatly with the reaction rate and the reaction effect of raw water, the reduction that the energy consumption is also great.

Drawings

FIG. 1 is a schematic structural diagram of an electrochemical ammonia nitrogen digestion device of the utility model;

fig. 2 is a schematic view of the present invention;

FIG. 3 is a schematic structural diagram of a wave plate of the electrochemical ammonia nitrogen digestion device;

reference numerals: 1. the device comprises a first reaction unit, a second reaction unit, a third reaction unit, a fourth reaction unit, a fifth reaction unit, a water inlet, a first overflow plate, a second overflow plate, a first cathode, a second cathode, a first anode, a first cathode, a second anode, a second cathode, a first cathode, a second cathode, a first overflow plate, a second overflow plate, a first cathode, a second cathode.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Referring to fig. 1 to 2, an electrochemical ammonia nitrogen digestion device comprises a first reaction unit 1, a second reaction unit 2, a third reaction unit 3, a fourth reaction unit 4 and a fifth reaction unit 5, a water inlet 6 is arranged at the bottom of the first reaction unit 1, the first reaction unit 1 is communicated with the second reaction unit 2 through an overflow plate I7, the second reaction unit 2 is communicated with a third reaction unit 3 through an opening at the bottom, the third reaction unit is communicated with a fourth reaction unit 4 through an overflow plate II 8, the fourth reaction unit 4 is communicated with the fifth reaction unit 5 through an opening at the bottom, a first cathode 10 is arranged in the first reaction unit 1, an anode I20 is arranged in the second reaction unit 2, a cathode II 30 is arranged in the third reaction unit 3, an anode II 40 is arranged in the fourth reaction unit 4, and a cathode III 50 is arranged in the fifth reaction unit 5;

the distance between the first cathode 10 and the first anode 20 is 20-40mm, the distance between the first anode 20 and the second cathode 30 is 20-40mm, the distance between the second anode 40 and the second cathode 30 is 20-30mm, the distance between the second anode 40 and the third cathode 50 is 15-20mm, the first cathode 10 is a titanium alloy electrode plate, the first anode 20 is an anode plate made of titanium-based lead oxide, the second cathode 30 is a nitrogen-doped nano-diamond cathode plate, the second anode 40 is a boron-doped nano-diamond anode plate, and the third cathode 50 is a titanium alloy electrode plate containing graphite, platinum and gold; the first reaction unit 1, the second reaction unit 2, the third reaction unit 3, the fourth reaction unit 4 and the fifth reaction unit 5 are all detachably connected.

The substrates of the nitrogen-doped nano-diamond cathode plate and the boron-doped nano-diamond anode plate are made of p-type Si or Mo, Ta and Ti metal materials, one side of the substrate of the nitrogen-doped nano-diamond cathode facing the boron-doped nano-diamond anode is coated with a layer of nitrogen-doped nano-diamond film, and one side of the substrate of the boron-doped nano-diamond anode facing the nitrogen-doped nano-diamond cathode is coated with a layer of boron-doped nano-diamond film.

The first reaction unit 1, the second reaction unit 2, the third reaction unit 3, the fourth reaction unit 4 and the fifth reaction unit 5 are all tank bodies made of polytetrafluoroethylene.

The cathode III 50 can also be a niobium-based alloy electrode plate containing graphite, platinum and gold.

An electrochemical ammonia nitrogen digestion method comprises the following steps:

the method comprises the following steps: raw water is introduced into the first reaction unit 1, and the first cathode 10, the first anode 20, the second cathode 30, the second anode 40 and the third cathode are electrified;

step two: the total nitrogen is measured by adopting alkaline potassium persulfate ultraviolet spectrophotometry to the raw water in the first reaction unit 1 at regular time according to the quality of the raw water;

step three: when the total nitrogen concentration of the sewage in the first reaction unit 1 is not higher than 105mg/L at least, the first reaction unit 1 is introduced into the second reaction unit 2 through the overflow plate I7 for electrolysis;

step four: when the total nitrogen concentration in the second reaction unit 2 is not higher than 60mg/L at least, the second reaction unit 2 is introduced into the third reaction unit 3 through the bottom opening for electrolysis;

step five: when the total nitrogen concentration reaches at least not higher than 30mg/L, the second reaction unit 2 is introduced into the third reaction unit 3 through the bottom opening for electrolysis;

step six: when the total nitrogen concentration reaches at least not higher than 10mg/L, the third reaction unit 3 is introduced into the fourth reaction unit 4 through the bottom opening for electrolysis;

step seven: when the total nitrogen concentration reaches at least not higher than 1mg/L, the fourth reaction unit 4 is introduced into the fifth reaction unit 5 through the bottom opening for electrolysis until marking and discharging.

In specific implementation, raw water passes through the first reaction unit, the cathode generates H and OH,

the generated H and OH react with NO3, organic substances (COD and BOD) ammonia nitrogen and the like to generate CO2, H2O and N2; because the raw water has higher concentration, a large amount of denitrification operation can be carried out in the first reaction unit by ammonia nitrogen and total nitrogen of the raw water, and the specific reaction principle is as follows:

deaminizing nitrogen principle (main reaction 1):

NH3+ HOCl → NH2Cl + H2O (monochloramine)

NH2Cl + HOCl → NHCl2+ H2O (dichloramine)

2NH2Cl + HOCl → N2 ≠ +3HCl + H2O (denitrogenation primary reaction one)

Denitrified nitrogen principle (main reaction 2):

NH3+O·—→NO3-+H2O

NO3-+H·—→NO2-+H2O

NO2- + H · → N2 ↓ + H2O (denitrogenation second main reaction)

Meanwhile, the oxidation effect of the boron-doped nano-diamond anode and the indirect oxidation effect of the nitrogen-doped nano-diamond cathode are that oxygen in sewage is reduced to generate the oxidability of hydroxyl at the nitrogen-doped nano-diamond cathode to form the synergistic effect of a positive electrode and a negative electrode, the treatment effect of sewage is enhanced, the current efficiency is improved, so that the oxygen can easily obtain electrons at the nitrogen-doped nano-diamond cathode to generate H2O2, H2O2 has stronger oxidability and can assist the boron-doped nano-diamond anode in oxidizing and degrading organic pollutants in water to improve the sewage treatment efficiency, the tank voltage of the tank body is reduced at the same time, the current efficiency is improved, and compared with a common electrode, the current consumption of the organic matters with the same oxidation amount can be reduced by 1/2 by reducing the oxygen-reduced nano-diamond cathode

200 percent, thereby reducing the energy consumption and the sewage treatment cost.

The cathode I10, the anode I20, the cathode II 30, the anode II 40 and the cathode III 50 are all honeycomb bodies combined by wave plates, each honeycomb body is formed by a plurality of formed stainless steel wave plates, the two sides of each honeycomb body are provided with short planes, the two end faces of each honeycomb body form angles of 60 +/-10 degrees in the same direction, adjacent superposed faces are formed by spot welding or tongue piece bending insertion occlusion connection, and the honeycomb bodies are naturally placed in an inclined position of 60 +/-10 degrees; due to the fact that the contact area is increased, the treatment efficiency of sewage in unit time is increased, scum adhesion can be effectively prevented, and the treatment efficiency is guaranteed.

Every reaction unit separates into anode chamber and cathode chamber, and the negative pole and the positive pole of two adjacent reaction units compound into combined electrode, the embodiment of the utility model provides an in the reaction unit be 5, and series connection between 5 reaction units, the positive pole of fourth reaction unit 4 and the positive negative pole of the positive pole 10 of first reaction unit 1 connect the positive negative pole of pulse direct current stationary power supply respectively as the end electrode.

The first anode 20 is a titanium-based lead dioxide electrode, the first cathode 10 is a titanium alloy electrode plate, that is, the composite electrode comprises an anode surface and a titanium plate cathode surface of the titanium-based lead dioxide, the size of the composite electrode 4 in the embodiment is 400 x 500mm, the thickness is 3mm, taking actual raw water treatment as an example, the quality of secondary biochemical treatment wastewater is as follows: the conductance is 34.7ms/cm, the pH is 7.8, the COD is 530mg/L, the ammonia nitrogen is 70.33mg/L, the chroma is 220, and the total nitrogen is 210.5 mg/L.

The wastewater to be treated is lifted by a pump and is sent into a water inlet of a first reaction unit 1 of the electrochemical ammonia nitrogen digestion device, enters the first reaction unit, flows along a first cathode 10 and an overflow plate, then sequentially flows into a following reaction unit and the overflow plate, flows out through a fifth reaction unit 5 in a zigzag shape, and nitrate nitrogen and nitrite nitrogen in the wastewater complete reduction reaction in a cathode chamber; the wastewater flowing out of the fifth reaction unit 5 flows through the reaction units in sequence from the anode chamber of the first reaction unit in a cocurrent flow manner until the wastewater flows out of the water outlet of the anode chamber of the last reaction unit, and the ammonia nitrogen, the organic nitrogen and the like in the wastewater complete oxidation reaction in the anode chamber.

The electrolysis condition of each reaction unit in the embodiment of the utility model is as follows: current density of

15mA/cm2, the hydraulic retention time of each unit is 6min, and the quality of the wastewater treated by the electrochemical method of the utility model and the quality of the treated wastewater are obviously reduced.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (7)

1. The utility model provides an electrochemistry ammonia nitrogen digestion equipment which characterized in that: comprises a first reaction unit (1), a second reaction unit (2), a third reaction unit (3), a fourth reaction unit (4) and a fifth reaction unit (5), a water inlet (6) is arranged at the bottom of the first reaction unit (1), the first reaction unit (1) is communicated with the second reaction unit (2) through an overflow plate I (7), the second reaction unit (2) is communicated with the third reaction unit (3) through a bottom opening, the third reaction unit is communicated with the fourth reaction unit (4) through an overflow plate II (8), the fourth reaction unit (4) is communicated with the fifth reaction unit (5) through a bottom opening, a cathode I (10) is arranged in the first reaction unit (1), an anode I (20) is arranged in the second reaction unit (2), a cathode II (30) is arranged in the third reaction unit (3), and an anode II (40) is arranged in the fourth reaction unit (4), a third cathode (50) is arranged in the fifth reaction unit (5); the distance between the first cathode (10) and the first anode (20) is 20-40mm, the distance between the first anode (20) and the second cathode (30) is 20-40mm, the distance between the second anode (40) and the second cathode (30) is 20-30mm, the distance between the second anode (40) and the third cathode (50) is 15-20mm, the first cathode (10) is a titanium alloy electrode plate, the first anode (20) is an anode plate of titanium-based lead oxide, the second cathode (30) is a nitrogen-doped nano diamond cathode plate, the second anode (40) is a boron-doped nano diamond anode plate, and the third cathode (50) is a titanium alloy electrode plate containing graphite, platinum and gold.

2. The electrochemical ammonia nitrogen digestion device according to claim 1, characterized in that: the first reaction unit (1), the second reaction unit (2), the third reaction unit (3), the fourth reaction unit (4) and the fifth reaction unit (5) are detachably connected.

3. The electrochemical ammonia nitrogen digestion device according to claim 1, characterized in that: the substrates of the nitrogen-doped nano-diamond cathode plate and the boron-doped nano-diamond anode plate are made of p-type Si or Mo, Ta and Ti metal materials, one side of the substrate of the nitrogen-doped nano-diamond cathode facing the boron-doped nano-diamond anode is coated with a layer of nitrogen-doped nano-diamond film, and one side of the substrate of the boron-doped nano-diamond anode facing the nitrogen-doped nano-diamond cathode is coated with a layer of boron-doped nano-diamond film.

4. The electrochemical ammonia nitrogen digestion device according to claim 1, characterized in that: the first reaction unit (1), the second reaction unit (2), the third reaction unit (3), the fourth reaction unit (4) and the fifth reaction unit (5) are all groove bodies made of polytetrafluoroethylene.

5. The electrochemical ammonia nitrogen digestion device according to claim 1, characterized in that: the cathode III (50) can also be a niobium-based alloy electrode plate containing graphite, platinum and gold.

6. The electrochemical ammonia nitrogen digestion device according to claim 1, characterized in that: the cathode I (10), the anode I (20), the cathode II (30), the anode II (40) and the cathode III (50) adopt a honeycomb body (91) combined by wave plates (9).

7. The electrochemical ammonia nitrogen digestion device according to claim 6, characterized in that: the honeycomb body (91) is formed by a plurality of stainless steel corrugated plates, short planes are arranged on two sides of the stainless steel corrugated plates, two end faces of the stainless steel corrugated plates are in the same direction at an angle of 60 +/-10 degrees, adjacent superposed faces are formed by spot welding or tongue piece bending insertion occlusion connection, and the honeycomb body is naturally placed in an inclined position at an angle of 60 +/-10 degrees.

Images