CN102219323B - Method for simultaneously removing organic pollutants and ammonia in waste water and reactor - Google Patents

Abstract

A method and reactor for simultaneously removing organic pollutants and ammonia in wastewater. The catalytic oxidation degradation of organic pollutants by activated oxygen and the removal of ammonia by spray blowing are realized simultaneously in the same reactor. The reactor consists of an upper part for blowing off ammonia and a lower part for catalytic oxidation of activated oxygen. Air intake composition. After the pH of the wastewater is adjusted, it enters the atomizing nozzle through the water distribution pipe at the upper end, and the air enters the reactor through the microporous aeration plate or the air inlet. After blowing off and removing, the ammonia gas is sent to the next stage for treatment after it escapes from the top outlet. The mist falls to the activated oxygen catalytic oxidation tank at the lower end, and the air enters through the microporous aeration plate at the lower end, and reacts with the catalyst in the catalytic oxidation tank to generate oxygen-containing free radicals to oxidize and remove organic pollutants in wastewater. The invention is applicable to the treatment of various ammonia-containing organic waste water.

Description

A method and reactor for simultaneously removing organic pollutants and ammonia in wastewater

technical field

The invention relates to a method and a reactor for simultaneously removing organic pollutants and ammonia in waste water, belonging to the technical field of water pollution control. the

Background technique

As a widely used advanced oxidation technology for water treatment, Fenton oxidation is especially suitable for the treatment of some refractory or biologically toxic industrial wastewater such as phenols, aromatic amines, aromatic hydrocarbons, pesticides and nuclear waste. The reason why Fenton's reagent has a very strong oxidation ability is that hydrogen peroxide can generate hydroxyl radicals (OH) under the catalysis of iron ions, and OH has a stronger oxidation electrode potential (2.8V ), which is 35% and 59% higher than ozone (O ₃ , 2.07V) and hydrogen peroxide (hydrogen peroxide, 1.77V), respectively, and its oxidation ability is second only to fluorine; in addition, OH also has high electronegativity ( Electrophilicity), its electron affinity is 569.3KJ, it is easy to attack high electron cloud density points, and then as an intermediate product to realize the deep oxidation and decomposition of pollutants O ₃ , hydrogen peroxide, Cl ₂ , O and other strong oxidant intermediate products , using the strong oxidation properties of these intermediates to completely oxidize organic matter in wastewater to CO ₂ and H ₂ O. The traditional Fenton reaction has three limitations in large-scale application: ① it must be carried out in an acidic medium with pH<3; ② the existing form of conventional Fenton catalyst (Fe ²⁺ or Fe ³⁺ ) in aqueous solution Affected by the pH of the medium, total iron concentration, storage time and other factors, its separation and repeated use face many difficulties; ③Although H ₂ O ₂ is a convenient and clean oxygen source, it is expensive, poor in stability, The disadvantages of low utilization rate and limitations in storage and transportation. As a result, Fenton technologies such as light-Fenton technology, electric-Fenton technology, ultrasonic-Fenton technology, photoelectric-Fenton technology, etc., which combine multiple physical and chemical units, came into being; at the same time, zero-valent iron and its composites The representative heterogeneous Fenton reaction can also solve the shortcomings of the traditional Fenton reaction. However, the current Fenton system still does not solve the disadvantages of high price and low utilization rate of H ₂ O ₂ .

Ammonia-containing wastewater produced in petrochemical, metallurgy, food and other industries has aggravated the eutrophication of water bodies. The impact of ammonia nitrogen wastewater on the environment has attracted the attention of the field of environmental protection and the global scope. The research and development of economical and efficient nitrogen removal treatment technology has become the focus and hot spot in the field of water pollution control engineering. The main methods for removing ammonia nitrogen are: physical method, chemical method and biological method. At present, the widely used ammonia removal technologies mainly include ion exchange method, stripping-stripping method, chemical precipitation method, break point chlorination method, catalytic cracking and so on. Although the ammonia nitrogen removal rate of the ion exchange method is high, when the ammonia nitrogen concentration is high, the resin regeneration is frequent and the operation is difficult, and the regeneration liquid is still high ammonia nitrogen wastewater, the consumption of chemicals is large, and the treatment cost is high; There is a difference between the actual concentration of volatile substances such as ammonia nitrogen and the equilibrium concentration. Under alkaline conditions, air stripping or steam stripping is used to continuously transfer volatile substances such as ammonia nitrogen in the wastewater from the liquid phase to the gas phase. In order to achieve the purpose of removing ammonia nitrogen in wastewater, the stripping method can remove ammonia nitrogen, and the removal rate can reach 60% to 95%. The process flow is simple and the treatment effect is stable. As a mother liquor, it can also be absorbed by water to produce ammonia water or by sulfuric acid to produce ammonium sulfate by-product according to market demand, and the tail gas is returned to the stripping tower, but when the water temperature is low, the stripping efficiency is low, so it is not suitable for use in cold winter; chemical precipitation method It is a method to reduce the concentration of dissolved pollutants in water by adding a certain chemical agent to ammonia nitrogen wastewater to make it react with some soluble pollutants in the wastewater to form insoluble salts and precipitate them. Treatment of various concentrations of ammonia nitrogen wastewater, especially suitable for the treatment of high concentration ammonia nitrogen wastewater; the breakpoint chlorination method is to add excessive chlorine or sodium hypochlorite, and it is a method for the complete oxidation of ammonia in wastewater to _N2 , and the reaction speed of this method is fast , requires less equipment, but requires high safety use and storage of liquid chlorine, and high processing costs; catalytic cracking provides a comprehensive treatment and recovery method for ammonia/ammonium-containing wastewater generated in the catalyst production process. However, the current methods for removing ammonia from wastewater cannot effectively remove organic pollutants in wastewater without exception.

At present, there are few reports on the methods and reactors for simultaneous removal of organic pollutants and ammonia in wastewater. "Journal of Fudan University" (Volume 45, No. 3, 2006) reported a research paper entitled "Influencing Factors of Ammonia Nitrogen Removal by Electrochemical Oxidation". The concentration dropped from 26.8 to 6.1mg/L, and the concentration of ammonia nitrogen dropped from 19.9 to 0.1mg/L after the effluent treatment of the secondary sedimentation tank. At the same time, this process can remove organic matter in urban sewage to a certain extent; In China, there are only related patents on the removal of organic pollutants in wastewater by Fenton oxidation and the removal of ammonia by stripping method, such as the utility model invention patent of CN2937066Y, which is entitled " High-dispersion spray ammonia removal tower" patent, this utility model provides a high-dispersion spray ammonia removal tower, its high-dispersion elements are arranged in the tower body of the ammonia removal tower, located above the air inlet distributor, and the high-dispersion elements are formed by atomization Composed of nozzles and distribution water pipes, the atomizing nozzles are set up or down, and communicate with the feed water pump through the distribution water pipes and water inlet pipes; the tower uses high dispersion components to highly disperse the ammonia nitrogen wastewater, increasing the specific surface area of the liquid, and improving the solubility in water. The rate at which free ammonia escapes from the liquid phase, so as to achieve the purpose of removing ammonia nitrogen in the solution. Another example is the invention patent of CN101445290A, which discloses a patent titled "A kind of environmental protection and efficient waste water ammonia removal process and its equipment". Ammonia air is introduced into the inlet of the blower through pipes for recycling, so that the ammonia removal efficiency can be maintained in a relatively high range. the

The method of the invention is to degas and remove the ammonia from waste water containing organic pollutants and ammonia, and remove the organic pollutants by catalytically activating the Fenton oxidation of molecular oxygen. Ammonia-containing organic wastewater is sprayed into the reactor from the atomization nozzle through the aeration tube, and the air pump is started to feed air from the air inlet through the microporous aeration plate, and the air flow is adjusted. After atomization, the ammonia in the wastewater is blown off in the air. The catalyst in the catalytic oxidation tank at the lower end of the reactor can catalyze and activate the molecular oxygen in the oxidation tank to generate strong oxidative oxidative species, thereby removing organic pollutants in wastewater. The reactor for simultaneous removal of organic pollutants and ammonia in wastewater established by the invention is suitable for the treatment of various ammonia-containing organic wastewater, with high efficiency, environmental friendliness, no secondary pollution, compact equipment, easy operation, and easy control of the entire reactor , in line with the needs of the actual water treatment unit. the

Contents of the invention

The purpose of the present invention is to simultaneously realize the catalytic oxidation degradation of organic pollutants by activated oxygen and the removal of ammonia by spray blowing in the same water treatment unit, and provide a reactor capable of simultaneously removing organic pollutants and ammonia in water. the

The technical solution of the present invention is: a method for simultaneously removing organic pollutants and ammonia in waste water, characterized in that, in a reactor whose upper part is a chamber for blowing off ammonia and the lower part is an activated oxygen catalytic oxidation tank, the After the pH of the ammonia-containing organic wastewater is adjusted, it is sprayed into the reactor through the atomizing nozzle on the upper part of the blowing and removing ammonia chamber on the upper part of the reactor, and the air pump is started at the same time, and the air is passed through the micropores at the bottom of the activated oxygen catalytic oxidation tank on the lower part of the reactor Aeration plate exposure, or through the microporous aeration plate exposure and the air inlet at the lower part of the blowing and removal ammonia chamber, it is sent into the reactor, and the air flow is adjusted. After atomization, the ammonia in the waste water is in the air The air is blown off and removed, and is sent to the next stage of treatment along with the air overflowing from the escape port at the top of the reactor; the mist drops to the activated oxygen catalytic oxidation tank at the lower part of the reactor, and the catalyst catalyzes the activation of molecules in the activated oxygen catalytic oxidation tank Oxygen generates strong oxidizing oxygen-containing free radicals, oxidizes and removes organic pollutants in wastewater, and the water after blowing off ammonia and catalytic oxidation to remove organic matter flows out from the water outlet. the

According to the above technical scheme, the catalyst is ferrous sulfate, ferric sulfate, zero-valent iron, ferric oxide, ferric oxide or ferric oxyhydroxide. the

According to the above technical scheme, the concentration of the catalyst in the waste water is 0.2-1g/L, the molecular oxygen dissolves air in the waste water through the microporous aeration plate, and the dissolved oxygen concentration is 0.5-2.0mg/L. the

According to the above technical scheme, the pH value is within the range of 10-12. the

A reactor for simultaneously removing organic pollutants and ammonia in wastewater according to the present invention, its structure includes a reactor shell, an atomizing nozzle, a water outlet, a catalyst, an air pump, a microporous aeration plate, an ammonia escape outlet, and a feeding outlet, sludge outlet, power pump, perforated tray, blowing and removing ammonia chamber, catalytic oxidation tank, aeration pipe, water distribution pipe, and air inlet; the reactor consists of the upper blowing and removing ammonia chamber and the lower catalytic oxidation Pool composition; atomizing nozzles are evenly installed on the water distribution pipe, set in the upper part of the reactor to remove ammonia, the inlet of the water distribution pipe is connected to the outlet of the power water pump, and the perforated tray is set in the reactor to remove ammonia) , located between the feeding port and the atomizing nozzle, the microporous aeration plate is located at the bottom of the catalytic oxidation tank in the reactor, the catalyst is on the microporous aeration plate in the catalytic oxidation tank, the outlet of the air pump and the air inlet and the aeration The air pipe is connected, the aeration pipe extends into the lower part of the microporous aeration plate, the water outlet is located at the lower part of the air inlet on the upper partition of the catalytic oxidation tank, the mud discharge port is located near the bottom of the reactor, and the ammonia gas escape port is located in the reactor top. the

In the method for simultaneously removing organic pollutants and ammonia in wastewater of the present invention, ammonia can be removed by blowing off during the droplet drop process, and on the other hand, can be removed by blowing off through the perforated tray of the reactor. The perforated tray can increase the residence time of droplet blowing to remove ammonia, thereby increasing the efficiency of ammonia removal. Ammonia gas overflows from the ammonia gas outlet at the top of the reactor. The mist falls to the catalytic oxidation tank at the lower end of the reactor, and the air is exposed through the microporous aeration plate at the bottom of the catalytic oxidation tank, and reacts with the catalyst in the catalytic oxidation tank to generate strong oxidative oxygen-containing free radicals, which oxidize and remove the pollutants in the wastewater. Organic Pollutants. The water after blowing off ammonia and catalytic oxidation to remove organic matter flows out from the water outlet. By adjusting the wastewater flow rate, air flow, pH and other adjustments, the air and the catalyst can fully contact and react with the wastewater to achieve the best efficiency of removing ammonia and organic matter. the

The advantages of the present invention are as follows:

1. Combining air blowing to remove ammonia and catalytic activation of molecular oxygen to remove organic matter, the organic pollutants and ammonia in water can be removed simultaneously in the same reactor. the

2. The use of atomizing nozzles and perforated trays increases the contact area and contact time of ammonia and gas in wastewater. the

3. Oxygen molecules in the air are used as the oxygen source for catalytic oxidation. The oxygen source has a wide range of sources, low cost and good economy.

4. Various parameters are easy to control, and the parameters can be reacted according to the conditions at any time. the

5. The reactor for simultaneous removal of organic pollutants and ammonia in wastewater established by the present invention is suitable for the treatment of various ammonia-containing organic wastewater. The equipment is compact, easy to operate, and the entire reactor is easy to control. There is great potential for application in the area of governance. the

Description of drawings

Fig. 1 is a structural schematic diagram of a reactor for simultaneously removing organic matter and ammonia in wastewater. the

Detailed ways

The structure of the reactor for simultaneously removing organic matter and ammonia in waste water of the present invention is shown in FIG. 1 . The structure of the reactor includes a reactor shell 1, an atomizing nozzle 2, a water outlet 3, a catalyst 4, an air pump 5, a microporous aeration plate 6, an ammonia outlet 7, a feeding port 8, a mud discharge port 9, a power Water pump 10, perforated tray 11, blow-off ammonia chamber 12, catalytic oxidation tank 13, aeration pipe 14, water distribution pipe 15, and air inlet 16; Oxidation tank 13 is composed of; atomizing nozzles 2 are evenly installed on the water distribution pipe 15, and are arranged on the upper part of the blowing off ammonia chamber 12 in the reactor. In the internal blowing and removing ammonia chamber 12, it is located between the feeding port 8 and the atomizing nozzle 2. The microporous aeration plate 6 is located at the bottom of the catalytic oxidation tank 13 in the reactor, and the catalyst 4 is in the micropore of the catalytic oxidation tank 13. On the aeration plate 6, the outlet of the air pump 5 communicates with the air inlet 16 and the aeration pipe 14, the aeration pipe 14 extends into the lower part of the microporous aeration plate 6, and the water outlet 3 is located on the upper part of the upper partition of the catalytic oxidation tank 13 The lower part of the air inlet 16, the mud discharge port 9 is located near the bottom of the reactor, and the ammonia escape port 7 is located at the top of the reactor. the

Through the air pump 5, the air is passed into the reactor through the air inlet 16 or through the aeration pipe 14, and the ammonia-containing organic wastewater is sprayed out through the atomizing nozzle 2, and the ammonia in the sprayed highly dispersed droplets is neutralized under the action of the air. It is removed and sent to the next level of treatment after escaping from the ammonia gas outlet 7; the mist drops to the catalytic oxidation tank at the bottom of the reactor, and the catalyst in the catalytic oxidation tank reacts with the air exposed by the microporous aeration plate 6 to form high Oxidative oxygen-containing free radicals, oxidize and remove organic pollutants in wastewater. the

Example 1

Treatment of landfill leachate in a reactor that simultaneously removes organic pollutants and ammonia from wastewater

Take 30L of landfill leachate, adjust the pH to 12, the COD is 1835mg/L, and the NH ₃ -N is 1367mg/L. The wastewater is sprayed into the blowing and removing ammonia chamber through the atomizing nozzle, and at the same time, air is introduced into the catalytic oxidation tank to make the dissolved oxygen concentration in the water 0.5mg/L, and 24g of iron sulfate is added. After 120 minutes, the NH ₃ -N of the wastewater The removal rate of NH ₃ -N is about 73%, the COD of wastewater is 632mg/L, and the removal rate of organic pollutants is about 65%.

Example 2

Treatment of landfill leachate in a reactor that simultaneously removes organic pollutants and ammonia from wastewater

Take 30L of landfill leachate, adjust the pH to 11, the COD is 1987mg/L, and the NH ₃ -N is 2691mg/L. The wastewater is sprayed into the blowing and removing ammonia chamber through the atomizing nozzle, and at the same time, air is introduced into the catalytic oxidation tank to make the dissolved oxygen concentration in the water 1.0mg/L, add 20g of ferric oxide, and the NH ₃ -N of the wastewater is 989mg/L L, the removal rate of NH ₃ -N is about 63%, after 120 minutes, the COD of the wastewater is 598mg/L, and the removal rate of organic pollutants is about 70%.

Example 3

Treatment of wastewater in a reactor that simultaneously removes organic pollutants and ammonia from wastewater

Take 30L of wastewater, pH=12, COD 1530mg/L, NH ₃ -N 1269mg/L. The wastewater is sprayed into the blowing and removing ammonia chamber through the atomizing nozzle, and at the same time, air is introduced into the catalytic oxidation tank to make the dissolved oxygen concentration in the water 1.2mg/L, and 18g of iron sulfate is added. After 120 minutes, the NH ₃ -N of the wastewater The removal rate of NH ₃ -N is about 62%, the COD of wastewater is 543 mg/L, and the removal rate of organic pollutants is about 65%.

Example 4

Treatment of wastewater in a reactor that simultaneously removes organic pollutants and ammonia from wastewater

Take 30L of wastewater, pH=11.5, COD is 1610mg/L, NH ₃ -N is 2013mg/L. The wastewater is sprayed into the blowing and removing ammonia chamber through the atomizing nozzle, and at the same time, air is introduced into the catalytic oxidation tank to make the dissolved oxygen concentration in the water 1.4mg/L, and 25g of iron oxyhydroxide is added. After 120 minutes, the NH ₃ - N is 983mg/L, the removal rate of NH ₃ -N is about 51%, the COD of wastewater is 812mg/L, and the removal rate of organic pollutants is about 50%.

Example 5

Treatment of wastewater in a reactor that simultaneously removes organic pollutants and ammonia from wastewater

Take 30L of wastewater, adjust the pH to 10, the COD is 912mg/L, and the NH ₃ -N is 387mg/L. The wastewater is sprayed into the blowing and removing ammonia chamber through the atomizing nozzle, and at the same time, air is introduced into the catalytic oxidation tank to make the dissolved oxygen concentration in the water 1.2mg/L, and 20g of ferric sulfite is added. After 120 minutes, the NH ₃ - N is 152mg/L, the removal rate of NH ₃ -N is about 61%, the COD of wastewater is 543mg/L, and the removal rate of organic pollutants is about 40%.

Example 6

Treatment of wastewater in a reactor that simultaneously removes organic pollutants and ammonia from wastewater

Take 30L of wastewater, adjust the pH to 12, the COD is 1230mg/L, and the NH ₃ -N is 296mg/L. The wastewater is sprayed into the blowing and removing ammonia chamber through the atomizing nozzle, and at the same time, air is introduced into the catalytic oxidation tank to make the dissolved oxygen concentration in the water 1.5mg/L, and 30g of iron sulfate is added. After 120 minutes, the NH ₃ -N of the wastewater The removal rate of NH ₃ -N is about 82%, the COD of wastewater is 672 mg/L, and the removal rate of organic pollutants is about 45%.

Example 7

Treatment of wastewater in a reactor that simultaneously removes organic pollutants and ammonia from wastewater

Take 30L of wastewater, adjust the pH to 11, the COD is 793mg/L, and the NH ₃ -N is 453mg/L. The wastewater is sprayed into the blowing and removing ammonia chamber through the atomizing nozzle, and at the same time, air is introduced into the catalytic oxidation tank to make the dissolved oxygen concentration in the water 1.8mg/L, and 15g of zero-valent iron is added. After 120 minutes, the NH ₃ - N is 123mg/L, the removal rate of NH ₃ -N is about 73%, the COD of wastewater is 247mg/L, and the removal rate of organic pollutants is about 70%.

Example 8

Treatment of wastewater in a reactor that simultaneously removes organic pollutants and ammonia from wastewater

Take 30L, adjust the pH to 12, the COD is 745mg/L, and the NH ₃ -N is 1208mg/L. The wastewater is sprayed into the blowing and removing ammonia chamber through the atomizing nozzle, and at the same time, air is introduced into the catalytic oxidation tank to make the dissolved oxygen concentration in the water 2.0mg/L, and 6g of ferroferric oxide is added. After 120 minutes, the NH ₃ in the wastewater -N is 432mg/L, the removal rate of NH ₃ -N is about 74%, the COD of wastewater is 372mg/L, and the removal rate of organic pollutants is about 50%.

Claims (5)

1. method of removing organic pollutant and ammonia in the waste water simultaneously; It is characterized in that; On a top is that stripping removes the ammonia chamber and the bottom is in the reactor drum in activation oxygen catalyzed oxidation pond, with pending contain ammonia organic waste water adjustment pH after, the atomizing nozzle that removes top, ammonia chamber via the stripping on reactor drum top sprays into reactor drum; Start pneumatic pump simultaneously; With air via the micro-pore aeration plate of the bottom, activation oxygen catalyzed oxidation pond of reactor lower part expose to the sun into, the inlet mouth that perhaps removes bottom, ammonia chamber via described micro-pore aeration plate and described stripping is sent into reactor drum, and regulates air flow quantity; Ammonia is removed under the stripping of air in the waste water of atomizing back, and follows air after the escape orifice that is positioned at reactor top overflows, to send next stage to handle; Droplet drops down onto the activation oxygen catalyzed oxidation pond of reactor lower part; The catalyst activate molecular oxygen produces the strong oxidizing property oxygen radical in activation oxygen catalyzed oxidation pond; Organic pollutant in the oxidation removal waste water, the water after stripping removes ammonia and catalyzed oxidation removal organism flows out from water outlet.

2. a kind of method of removing organic pollutant and ammonia in the waste water simultaneously as claimed in claim 1 is characterized in that described catalyzer is ferrous sulfate, ferric sulfate, Zero-valent Iron, red oxide of iron, Z 250 or hydrous iron oxide.

3. a kind of method of removing organic pollutant and ammonia in the waste water simultaneously as claimed in claim 1; It is characterized in that; The concentration of catalyzer in waste water is 0.2 ~ 1g/L, and in waste water, dissolved oxygen concentration is 0.5-2.0 mg/L to molecular oxygen through micro-pore aeration plate dissolved air.

4. a kind of method of removing organic pollutant and ammonia in the waste water simultaneously as claimed in claim 1 is characterized in that described pH value is in the 10-12 scope.

5. reactor drum of removing organic pollutant and ammonia in the waste water simultaneously; It is characterized in that the structure of reactor drum comprises that reactor shell (1), atomizing nozzle (2), water outlet (3), catalyzer (4), pneumatic pump (5), micro-pore aeration plate (6), ammonia escape orifice (7), charging opening (8), mud discharging mouth (9), power water pump (10), porous plate (11), stripping remove ammonia chamber (12), catalyzed oxidation pond (13), aeration tube (14), water distributor (15) and inlet mouth (16); Reactor drum is made up of except that the catalyzed oxidation pond (13) of ammonia chamber (12) and bottom the stripping on top; Atomizing nozzle (2) is uniformly distributed with and is installed on the water distributor (15); Be arranged on the interior stripping of reactor drum and remove top, ammonia chamber (12); Water distributor (15) import is communicated with power water pump (10) outlet; Porous plate (11) is arranged on the interior stripping of reactor drum and removes in the ammonia chamber (12), is positioned at position between charging opening (8) and the atomizing nozzle (2), and micro-pore aeration plate (6) is positioned at bottom, reactor drum catalyzed oxidation pond (13); On the micro-pore aeration plate (6) of catalyzer (4) in catalyzed oxidation pond (13); Pneumatic pump (5) outlet is communicated with inlet mouth (16) and aeration tube (14), and aeration tube (14) extend into micro-pore aeration plate (6) bottom, and water outlet (3) is positioned at the bottom of the upper spacer top inlet mouth (16) in catalyzed oxidation pond (13); Mud discharging mouth (9) is positioned at reactor drum near the bottom, and ammonia escape orifice (7) is positioned at reactor head.

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