CN103951055B - The method of denitrification process low ratio of carbon to ammonium waste water while of methanation - Google Patents

Abstract

The invention discloses a reactor for treating waste water with low carbon-to-nitrogen ratio by methanation and denitrification simultaneously, which comprises a cylinder and a three-phase separator located above the cylinder. The cylinder is located in the outer cylinder, the bottom of the outer cylinder and the inner cylinder are both open, the bottom of the outer cylinder is divided into a connected upper section and a lower section, the upper section of the bottom of the outer cylinder shrinks inward, the lower section of the bottom of the outer cylinder expands outward and forms a first-level baffle, and the inner cylinder The lower part of the outer cylinder expands outward to form a secondary baffle, and the upper and lower sections of the outer cylinder extend into the cavity of the cylinder body. The three-phase separator is divided into four areas: the air chamber area, the gas slow-release area, the precipitation area and the reflux area. The outer cylinder is provided with a peripheral water outlet weir on a circle at the upper part of the backflow area. The invention also discloses a waste water treatment method, which can simultaneously realize denitrification and methane production in a single reactor by controlling the C/N values in different stages. The invention has the advantages of being capable of deep removal of organic matter and nitrogen in waste water at the same time, with high removal efficiency, and capable of generating energy methane.

Description

Method for treating wastewater with low carbon-to-nitrogen ratio by methanation and denitrification simultaneously

technical field

The invention relates to the technical field of industrial wastewater treatment, in particular to a reactor and a method for treating wastewater with a low carbon-to-nitrogen ratio by methanation and denitrification simultaneously. The reactor can simultaneously realize anaerobic methanation and denitrification.

Background technique

UASB (up-flow anaerobic sludge bed, English abbreviation of Up-flow Anaerobic Sludge Bed/Blanket, hereinafter referred to as UASB) is composed of three parts: sludge reaction zone, gas-liquid-solid three-phase separator (including sedimentation zone) and air chamber . A large amount of anaerobic sludge remains in the bottom reaction zone, and sludge with good sedimentation and coagulation properties forms a sludge bed in the lower part. The wastewater to be treated flows from the bottom of the anaerobic sludge bed and is mixed with the sludge in the sludge bed, and the microorganisms in the sludge decompose the organic matter in the wastewater and convert it into biogas. The biogas is continuously released in the form of micro-bubbles, and the micro-bubbles are constantly merging during the rising process to gradually form larger bubbles. On the upper part of the sludge bed, due to the agitation of the biogas, a sludge with a relatively thin sludge concentration rises together with the water into the third Phase separator, when the biogas hits the reflection plate at the lower part of the separator, it is deflected around the reflection plate, then passes through the water layer and enters the gas chamber, where the biogas is concentrated in the gas chamber, and is exported with a conduit, and the solid-liquid mixture enters the three-phase through reflection In the settling area of the separator, the sludge in the wastewater flocculates, and the particles gradually increase and settle under the action of gravity. The sludge deposited on the inclined wall slides back to the anaerobic reaction zone along the inclined wall, so that a large amount of sludge accumulates in the reaction zone, and the treated effluent after being separated from the sludge overflows from the upper part of the overflow weir in the sedimentation zone, and then discharges the sewage mud bed. That is, the UASB can remove organic matter in wastewater and convert it into biogas.

The denitrification reaction in the wastewater treatment process is that NO ₃ ^- -N is converted into nitrogen gas and N ₂ escapes from the water under the action of denitrifying bacteria. Most denitrifying bacteria are heterotrophic facultative anaerobic bacteria. The denitrification process requires a large number of electron donors. The denitrification stage uses NO ₃ ^- -N as the electron acceptor and organic matter as the electron donor. The electron donor usually comes from External carbon sources, studies have shown that methanol, acetic acid and other small molecules that are not easily fermentable organic matter are more likely to be used by denitrifying bacteria, and the denitrification capacity is related to the amount of available carbon sources, that is, the C/N ratio.

In an anaerobic system where nitrate and organic matter exist at the same time, complex fermentable organic matter can be converted into organic acids and alcohols by hydrolyzing acid-producing bacteria, and hydrogen-producing acetogenic bacteria can convert organic acids and alcohols such as propionic acid and butyric acid For acetic acid, H ₂ and CO ₂ . Denitrifying bacteria can reduce nitrate nitrogen with the above-mentioned various organic matter as carbon sources. Methanogens mainly use acetic acid, H ₂ and CO ₂ as substrates to produce methane. The traditional theory holds that the presence of NO ₃ ^- -N will lead to competition between denitrifying bacteria and methanogenic bacteria, thereby inhibiting methanation. The inhibitory effect of denitrifying bacteria on methanogens is manifested in three aspects: ①The denitrifying bacteria group has an advantage in the competition for carbon source substrates; ②The denitrification process leads to an increase in the redox potential in the anaerobic system, which is not conducive to The growth of methanogenic bacteria; ③The intermediate products of denitrification reaction have a toxic effect on the methanogenic bacteria.

Therefore, the existing UASB has the disadvantage of not being able to simultaneously remove organic matter and nitrogen in wastewater, that is, denitrification and methanation reactions cannot occur simultaneously in a single UASB reactor.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a reactor and method for treating waste water with low carbon-to-nitrogen ratio by methanation and denitrification simultaneously. Through appropriate control means, adding specific carbon sources, and controlling different C/N values in different stages, denitrification and methanogenesis reactions can be realized simultaneously in a single reactor.

The present invention is achieved through the following technical solutions:

The reactor for methanation and denitrification treatment of wastewater with low carbon-to-nitrogen ratio includes a cylinder as the main body of the reactor and a three-phase separator located above the cylinder. A temperature control device is installed outside the cylinder. Inside the cylinder is a cylinder cavity, the cylinder cavity is a sludge reaction zone, an anaerobic sludge bed is provided at the bottom of the sludge reaction zone, and a water inlet is provided at the bottom of the cylinder, and the water inlet passes through The water inlet pipe is connected to the raw water tank, the water inlet pipe is provided with a water inlet pump, and the three-phase separator includes two layers of outer cylinder and inner cylinder, the inner cylinder is located in the outer cylinder, the outer cylinder and the inner cylinder The bottoms are all open, and the bottom of the outer cylinder is divided into a connected upper section and a lower section. The outer expansion forms a secondary baffle, the upper and lower sections of the outer cylinder extend into the cavity of the cylinder, and the three-phase separator is divided into four parts: air chamber area, gas slow release area, precipitation area and reflux area. The upper part of the outer cylinder above the inner cylinder is an air chamber area, the inner upper part of the inner cylinder is an air chamber slow-release area, and the area surrounded by the upper section of the outer cylinder bottom is a precipitation area. The gap area between the inner cylinder and the outer cylinder is the backflow area, and the outer cylinder is provided with a peripheral water outlet weir on the upper part of the backflow area, and the peripheral water outlet weir is connected to the water outlet, and the top of the outer cylinder is sealed And a gas outlet is provided at a position above the gas chamber area.

As a preferred embodiment of the above reactor, a water distributor for evenly distributing waste water is provided in the cavity of the cylinder between the anaerobic sludge bed and the water inlet.

As a preferred embodiment of the above reactor, the temperature control device is a constant temperature water bath device, and the constant temperature water bath device is arranged on the periphery of the cylinder.

As a preferred embodiment of the above reactor, a thermometer is provided on the upper part of the cylinder, and the thermometer extends into the cavity of the cylinder.

As a preferred embodiment of the above reactor, the cylinder is provided with a plurality of sampling ports at different heights, the sampling ports are connected to a sampling tube, and a sampling valve is provided on the sampling tube.

As a preferred embodiment of the above reactor, the gas outlet is connected to the gas collection container through a gas outlet pipe, and a gas purifier and a gas flow meter are arranged on the gas outlet pipe.

The invention also discloses a method for treating wastewater with a low carbon-to-nitrogen ratio by methanation and denitrification simultaneously, comprising the following steps:

A. The anaerobic sludge taken from the bottom of the factory wastewater treatment reactor is used as the inoculation sludge, and the inoculation sludge is cleaned with clean water to remove the residual wastewater on the surface, and then the inoculation sludge is inoculated into the reactor as the inoculation sludge. Anaerobic sludge bed;

B. Add waste water with a low carbon-to-nitrogen ratio into the raw water tank, use organic matter in the waste water as the carbon source and sodium nitrate as the nitrogen source, and control the operating temperature of the reactor at 34-36°C through the temperature control device to control the waste water Keep the pH value at 7.5-7.7, keep the influent flow rate of wastewater at 2.304L/d, and the hydraulic retention time at 73h; start the reactor, and the wastewater enters the cylinder of the reactor through the water inlet at the bottom of the reactor under the action of the inlet pump The cavity flows upward through the anaerobic sludge bed composed of inoculated sludge. The anaerobic reaction occurs between the wastewater and the sludge in the sludge bed, and biogas is generated to cause the sludge to stir, forming an upward flow of solid-liquid-gas mixture and continuing to rise. The position of the baffle is low, which can intercept the sludge particles in the upflow with high efficiency and complete the preliminary solid-liquid separation. Sludge particles complete the second solid-liquid separation; then the upflow occurs gas-liquid separation in the gas slow-release area, the separated gas enters the air chamber area, the separated liquid enters the sedimentation area through the reflux area, and the supernatant in the separated liquid Across the surrounding weir and discharge through the outlet;

C. In the first 10 days of reactor operation, control the concentration of nitrate nitrogen in the raw water tank to 0; on the 11th-31st day, control the carbon-nitrogen ratio of the raw water tank to 75:1; on the 32nd-62nd day On the 63rd to 98th day, the C/N ratio of the incoming water in the raw water tank was controlled to be 7.5:1.

As a preferred implementation of the above method, the step C is: controlling the concentration of total organic carbon (TOC) in the influent to remain unchanged, and increasing the concentration of nitrate nitrogen in the influent in stages.

As a preferred embodiment of the above method, the step C is specifically: in the 98 days of reactor operation, the total organic carbon TOC concentration in the raw water tank has been controlled to be 2250 mg/L; in the first 10 days of reactor operation, control The nitrate nitrogen concentration in the raw water tank was 0; on the 11th-31st day, the nitrate nitrogen concentration in the raw water tank was controlled to be 30mg/L; on the 32nd-62nd day, the nitrate nitrogen concentration in the raw water tank was controlled to 150mg/L; on the 63rd-98th day, control the concentration of nitrate nitrogen in the raw water tank to 300mg/L.

As a preferred implementation of the above method, in the step B, the gas entering the gas chamber area enters the gas outlet pipe through the gas outlet, is purified by a gas purifier, and then the gas flow is measured by a gas flow meter, and finally enters the gas The gas is collected by the collecting container; the concentration of the supernatant discharged from the water outlet is measured by the liquid concentration measuring instrument.

Compared with the prior art, the present invention has the following advantages:

In the method of the present invention, through appropriate control means, the TOC concentration of the influent is controlled to be constant, the concentration of nitrate nitrogen in the influent is increased step by step, and the C/N value of different stages is controlled to be different, so that denitrification can be realized simultaneously in a single reactor According to the purpose of the methanogenic reaction, it is obtained through experiments that in the UASB reactor, the removal rate of organic matter of more than 98.6% and the removal rate of nitrate nitrogen of more than 99.1% are obtained.

The present invention adopts UASB reactor to treat the organic matter in the waste water, which has the advantages of low energy consumption, less sludge output and high load; the present invention greatly simplifies the process flow of the waste water treatment, makes full use of the denitrification of the carbon source in the original waste water, and realizes The wastewater treatment concept of "treating waste with waste" achieves the purpose of deep removal of organic matter and nitrogen in wastewater at the same time, and can generate energy methane. In addition, the reactor used in the present invention adopts two stages of baffles at different heights, which can more fully intercept the sludge particles in the upflow, and the solid-liquid separation twice makes the solid-liquid separation more complete; and its three-phase separation The unique structure of the device, on the one hand, ensures the clarification of the water coming out of the surrounding weirs, on the other hand, the upper part is the secondary baffle, and the lower part is the sedimentation area formed by the inward contraction of the upper part of the bottom of the outer cylinder, which has a larger volume and better performance. The intercepted sludge is convenient for sludge sedimentation, and the sludge separated from the final sedimentation zone returns to the anaerobic sludge bed reaction zone, so that there is no need to set up sedimentation tanks and sludge return equipment, etc., the structure is simple, and the three-phase separation treatment High efficiency; the temperature control device adopts a constant temperature water bath device around the outside of the cylinder, which ensures the constant and stable operating temperature of the reactor; and the cylinder is equipped with multiple sampling ports at different heights, which can conveniently take samples of different heights. The sludge was analyzed for its microbial composition.

Description of drawings

Fig. 1 is a schematic diagram of the reactor structure of the present invention.

Fig. 2 is a time-varying chart of total organic carbon (TOC) concentration and removal rate in the effluent in the method of the present invention.

Fig. 3 is a graph showing the nitrate nitrogen NO ₃ --N concentration and removal rate of the influent and effluent water with time in the method of the present invention.

Fig. 4 is a time-varying diagram of the proportion of each gas component produced in the reactor in the method of the present invention.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

Please refer to Fig. 1, a kind of reactor of methanation and denitrification treatment low carbon nitrogen ratio wastewater provided by the present invention, comprises cylinder 1 as the main body of the reactor, and the three-phase separator located above cylinder 1, cylinder 1 is equipped with a temperature control device outside, the temperature control device is a constant temperature water bath device 2, and the constant temperature water bath device 2 is arranged on the periphery of the cylinder 1, which circulates around the cylinder 1 through the heat preservation circulating water 21 to control the operating temperature of the reactor. Inside the cylinder 1 is the cylinder cavity, which is the sludge reaction zone. The lower part of the sludge reaction zone is provided with an anaerobic sludge bed 11, and the bottom of the cylinder is provided with a water inlet 12. The inside of the cylinder cavity is anaerobic. A water distributor 13 for evenly distributing waste water is arranged between the sludge bed 11 and the water inlet 12 . A thermometer 14 is arranged on the upper part of the cylinder body 1, and the thermometer 14 extends into the cavity of the cylinder body. The water inlet 12 is connected to the raw water tank 16 through the water inlet pipe, and the water inlet pump 15 is arranged on the water inlet pipe. The three-phase separator includes an outer cylinder 3 and an inner cylinder 4. The inner cylinder 4 is located in the outer cylinder 3. The bottoms of the outer cylinder 3 and the inner cylinder 4 are both open. The bottom of the outer cylinder 3 is divided into a connected upper section 31 and a lower section 32. , the upper section 31 of the bottom of the outer cylinder 3 shrinks inwardly, the lower section 32 of the bottom of the outer cylinder 3 expands outwards and forms a primary baffle, the lower part of the inner cylinder 4 expands outwards to form a secondary baffle 41, the upper section 31 and the lower section of the outer cylinder 3 32 protrudes into the cylinder cavity, and the three-phase separator is divided into four areas: air chamber area 51, gas slow-release area 52, sedimentation area 53 and reflux area 54, and the upper part of the outer cylinder 3 is located above the inner cylinder 4. It is the air chamber area 50, the area in the upper part of the inner cylinder 4 is the air chamber slow-release area 52, the area surrounded by the upper section 31 of the bottom of the outer cylinder 3 is the precipitation area 53, and the gap area between the inner cylinder 4 and the outer cylinder 3 is the backflow Area 54, the outer cylinder 3 is provided with a peripheral water outlet weir 55 on the upper part of the backflow area 54, and the peripheral water outlet weir 55 is connected to the water outlet 56, and the top of the outer cylinder 3 is sealed and installed at a position above the air chamber area 51 There is a gas outlet 33, and the gas outlet 33 is connected to the gas collection container through a gas outlet pipe, and a gas purifier and a gas flow meter are arranged on the gas outlet pipe. The cylinder body 1 is provided with a plurality of sampling ports 17 at different height positions, and the sampling ports 17 are connected with sampling pipes, and the sampling pipes are provided with sampling valves.

The reactor used in the present invention adopts two stages of baffles at different heights, which can more fully intercept the sludge particles in the upflow, and the solid-liquid separation can be more fully separated by two solid-liquid separations; and its three-phase separator is unique On the one hand, it can ensure the clarification of the water coming out from the peripheral weir 55; Better interception of sludge, convenient for sludge sedimentation, and finally the sludge separated from the sedimentation zone returns to the anaerobic sludge bed 11 reaction zone, so that no sedimentation tank and sludge return equipment are needed, and the structure is simple. The phase separation treatment efficiency is high; the temperature control device adopts a constant temperature water bath device 2 surrounding the cylinder 1, which ensures a constant and stable operating temperature of the reactor; and the cylinder 1 is provided with multiple sampling ports 17 at different heights, It is convenient to take sludge of different heights to analyze the microbial composition.

The invention also discloses a method for treating wastewater with a low carbon-to-nitrogen ratio by methanation and denitrification simultaneously, comprising the following steps:

A. The anaerobic sludge taken from the bottom of the factory wastewater treatment reactor is used as the inoculation sludge, the concentration of the inoculation sludge is 20g/L, it is cleaned with clear water to remove the residual waste water on its surface, and then the inoculation sludge Sludge is inoculated into this reactor as anaerobic sludge bed 11;

B. Add waste water with a low carbon-to-nitrogen ratio into the raw water tank 16, use the organic matter sodium acetate in the waste water as the carbon source, and use sodium nitrate as the nitrogen source, and control the operating temperature of the reactor at 34-36°C through the temperature control device. The pH value of the wastewater is kept at 7.5-7.7, the influent flow rate of the wastewater is kept at 2.304L/d, and the hydraulic retention time is 73h; the reactor is started, and the wastewater enters the reaction through the water inlet 12 at the bottom of the reactor under the action of the inlet pump 15 The cylinder cavity of the device flows upward through the anaerobic sludge bed 11 composed of inoculated sludge. The wastewater and the sludge in the sludge bed undergo an anaerobic reaction to generate methane and cause sludge agitation, forming an upward flow of solid-liquid-gas mixing. Continue to rise, the position of the primary baffle is relatively low, which can intercept the sludge particles in the upward flow more efficiently and complete the preliminary solid-liquid separation. After the preliminary solid-liquid separation, the upward flow continues to rise through the secondary baffle 41 and second Separation of the sludge particles in the upflow for the first time completes the second solid-liquid separation; then the upflow undergoes gas-liquid separation in the gas slow release zone 52, the separated gas enters the gas chamber zone 51, and the separated liquid enters the sedimentation through the backflow zone 54 Zone 53, the supernatant in the separated liquid crosses the peripheral water outlet weir 55 and is discharged through the water outlet 56;

C. In the first 10 days of reactor operation, the concentration of nitrate nitrogen in the raw water tank 16 was controlled to be 0; on the 11th-31st day, the carbon-nitrogen ratio of the raw water tank 16 was controlled to be 75:1; on the 32nd - On day 62, control the C/N ratio of the feed water in the raw water tank 16 to 15:1; on days 63-98, control the C/N ratio of the feed water in the raw water tank 16 to 7.5:1.

Wherein, in the above step B, the gas entering the gas chamber area 51 enters the gas outlet pipe through the gas outlet 33, is purified by a gas purifier, and then the gas flow is measured by a gas flow meter, and finally enters the gas collection container to collect the gas Get up; measure the concentration of the supernatant discharged from the water outlet 56 by a liquid concentration measuring instrument.

Wherein, in the above step C, by controlling the TOC concentration of the influent water to be constant, the concentration of nitrate nitrogen in the influent water is increased step by step to control the carbon-nitrogen ratio C/N of the influent water at different stages. Specifically: in the 98 days of reactor operation, the total organic carbon TOC concentration in the raw water tank 16 was controlled to remain at 2250 mg/L; in the first 10 days of the reactor operation, the nitrate nitrogen concentration in the raw water tank 16 was controlled to be 0; On the 11th-31st day, control the nitrate nitrogen concentration in the raw water tank 16 to 30 mg/L; on the 32-62 day, control the nitrate nitrogen concentration in the raw water tank 16 to 150 mg/L; on the 63-98th day Day, control the influent nitrate nitrogen concentration in the raw water tank 16 to be 300mg/L.

In order to verify the effect of the method of the present invention, the applicant deliberately made an experimental example.

In this experimental example, the inlet water in the raw water tank 16 adopts the mixed solution of sodium acetate, sodium nitrate, trace element concentrated solution and tap water to simulate the composition of waste water, wherein the concentration of each component is as follows (mg/L): TOC is 2250 (equivalent COD3000); NO ₃ ^- -N is 0~300; NH ₄ HCO ₃ is 0 in the first 10 days 2024 and later; KH ₂ PO ₄ ·3H ₂ O is 800; (NH ₄ ) ₆ Mo ₇ O ₂₄ is 15; MgCl ₂ ·6H ₂ O is 100; MnCl ₂ ·4H ₂ O is 5; NiCl ₂ ·6H ₂ O is 5; CoC1 ₂ ·6H ₂ O is 5; CuC1 ₂ ·5H ₂ O is 5; CaCl ₂ is 50; NaCl is 10; FeCl ₂ is 25; H ₃ BO ₄ is ₅ ; ZnCl is 25; The pH of the wastewater influent is 7.6±0.1. The inoculated sludge for the experiment was taken from the bottom of the anaerobic reactor of China Resources Snow Brewery Wastewater Treatment, and was washed 3 times before inoculation to remove residual brewery wastewater on the sludge surface.

During the entire operation of the reactor, the carbon-nitrogen ratio C/N at each stage is controlled by adding a specific carbon source to the influent of the simulated wastewater and diluting it with water. In this experimental example, during the entire operation of the reactor, the operating temperature of the reactor is controlled by the temperature control device to maintain 34-36°C, the influent flow rate is maintained at 2.304L/d, the hydraulic retention time is 73h, and the total organic carbon in the influent is fixed. The concentration of TOC is 2250mg/L unchanged, and the concentration of nitrate nitrogen NO ₃ ^- -N in the influent is increased in stages; in the first 10 days of reactor operation, the concentration of nitrate nitrogen in the influent water in the raw water tank 16 is controlled to be 0; day, control the concentration of nitrate nitrogen in the raw water tank 16 to be 30 mg/L; on the 32nd to 62 days, control the concentration of nitrate nitrogen in the raw water tank 16 to be 150 mg/L; on the 63rd to 98th day, control the concentration of nitrate nitrogen in the raw water tank 16 The influent nitrate nitrogen concentration is 300mg/L.

The experimental results are shown in Figures 2 to 4. The first 10 days before the start of the experiment is the first stage. Sodium acetate is used as the carbon source in the simulated wastewater, and the concentration of NO ₃ ^- -N in the influent is 0. The main purpose of this stage is to make the sewage The mud adapts to the new wastewater and ensures the activity of the sludge. It can be seen from Figure 2 that the concentration of TOC in the effluent drops rapidly in this stage, and the removal rate of TOC reaches 86.36%;

Day 11-31 is the second stage, and the concentration of NO ₃ ^- -N in the simulated wastewater is increased to 30mg/L. At the same time, it can be seen from the analysis of Figure 2 and Figure 3 that the TOC concentration of the reactor effluent in this stage still maintains a downward trend, while The concentration of NO ₃ ^- -N in the effluent was approximately zero, and the removal rate of NO ₃ ^- -N was as high as 95%. By the 31st day, the concentration of TOC in the effluent was 172.97mg/L, the removal rate was 92.31%, and the concentration of NO ₃ ^- -N in the effluent was 0.41mg/L, the removal rate is 98.65%.

Day 32-62 is the third stage, and the concentration of NO ₃ ^- -N in the simulated wastewater is raised to 150mg/L. Simultaneously analyzing Figure 2 and Figure 3, it can be seen that the TOC removal rate of the reactor effluent at this stage remains above 90%. , while the concentration of NO ₃ ^- -N in the effluent rose slightly, but the magnitude was negligibly low, and the removal rate of NO ₃ ^- -N was still above 95%. By the 62nd day, the concentration of TOC in the effluent was 83.15 mg/L, and the removal rate is 96.30%, the effluent NO ₃ ^- -N concentration is 0.69mg/L, and the removal rate is 99.54%.

Day 63-98 is the fourth stage, and the concentration of NO ₃ ^- -N in the simulated wastewater is increased to 300mg/L. Analyzing Figure 2 and Figure 3 at the same time, it can be seen that the TOC removal rate of the reactor effluent at this stage remains above 95%. , while the NO ₃ ^- -N concentration in the effluent rose slightly compared with the third stage, but the concentration gradually decreased from 10.22 mg/L, and the NO ₃ ^- -N removal rate remained above 95%; the effluent TOC concentration was 29.505 on the 98th day mg/L, the removal rate is 98.69%, the effluent NO ₃ ^- -N concentration is 2.42mg/L, and the removal rate is 99.19%.

Fig. 4 is a diagram showing the time-varying proportion of each gas component produced in the reactor during the construction of the synchronous methanation and denitrification system. At the same time combined with the analysis of Figure 3, with the addition of NO ₃ ^- -N, the content of CH ₄ produced in the reactor decreased and the content of N ₂ and CO ₂ began to increase, and the increase of N ₂ was greater than that of CO ₂ , which was due to the reaction The nitrification process produces _{CO 2} , which in turn can be utilized by methanogenic bacteria. By the 98th day, the composition of the gas production had stabilized, in which N ₂ accounted for about 40%, CH ₄ accounted for about 50%, and CO ₂ accounted for about 10%. After the reactor runs stably, the gas production rate is 0.08L/h. After calculation, the specific N ₂ production rate of the reactor is 31.07mL/(gVSS·h), and the specific CH ₄ production rate is 38.83mL/(gVSS·h).

Combining Figure 2, Figure 3, and Figure 4, the reactor operates stably, the removal rate of TOC reaches 98.69%, and the removal rate of NO ₃ ^- -N reaches 99.19 _% ^. Stable, anaerobic methanation and denitrification are realized in a single anaerobic reactor.

The experimental results show that with the UASB reactor as the reaction vessel, sodium acetate as the carbon source, and sodium nitrate as the nitrogen source, the influent TOC concentration is controlled at 2250 mg/L, and the influent NO ₃ ^- -N concentration is controlled at 0 to 300 mg/L. The coupling of methanation and denitrification reactions in a single reactor can be quickly realized by gradually increasing the concentration of NO ₃ ^- -N in the reactor feed water and gradually reducing the carbon-to-nitrogen ratio C/N.

In the method of the present invention, through appropriate control means, the TOC concentration of the influent is controlled to be constant, the nitrate nitrogen concentration of the influent is increased step by step, and the C/N value of different stages is controlled to be different, so that denitrification and denitrification can be simultaneously realized in a single reactor. The purpose of the methanogenic reaction is obtained through experiments. In the anaerobic UASB reactor, the removal rate of organic matter of more than 98.6% and the removal rate of nitrate nitrogen of more than 99.1% are obtained.

The present invention adopts UASB reactor to treat the organic matter in the waste water, which has the advantages of low energy consumption, less sludge output and high load; the present invention greatly simplifies the process flow of the waste water treatment, makes full use of the denitrification of the carbon source in the original waste water, and realizes The wastewater treatment concept of "treating waste with waste" achieves the purpose of deep removal of organic matter and nitrogen in wastewater at the same time, and can generate energy.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention. Inside.

Claims (9)

1. the method for methanation simultaneously denitrification process low ratio of carbon to ammonium waste water, described method is used reactor and is comprised cylindrical shell as reactor body, and the triphase separator be positioned at above described cylindrical shell, described cylindrical shell outside is provided with temperature control unit, be cylindrical shell cavity in described cylindrical shell, described cylindrical shell cavity is sludge reaction district, bottom, described sludge reaction district is provided with anaerobic mud bed, described cylinder body bottom is provided with water-in, described water-in is connected to raw water box by water inlet pipe, described water inlet pipe is provided with intake pump, it is characterized in that: described triphase separator comprises urceolus and the two-layer cylindrical shell of inner core, described inner core is positioned at urceolus, equal opening bottom described urceolus and inner core, connected epimere and hypomere is divided into bottom described urceolus, bottom described urceolus, epimere inwardly shrinks, bottom described urceolus, hypomere expands outwardly and forms one baffle, the bottom of described inner core expands outwardly and forms secondary baffle plate, the epimere of described urceolus and hypomere stretch in described cylindrical shell cavity, air chamber district is divided in described triphase separator, gas slowly-releasing district, settling region and region, four, recirculating zone, the region of described urceolus high inside above inner core is air chamber district, the region of described inner core internal upper part is air chamber slowly-releasing district, the region that bottom described urceolus, epimere surrounds is settling region, gap area between described inner core and urceolus is recirculating zone, described urceolus is provided with peripheral weir being positioned at recirculating zone upper position on one week, described peripheral weir connects water outlet outward, described urceolus top seal and be provided with gas outlet being positioned at the position above air chamber district,

It is characterized in that, described method comprises the steps:

A, be seed sludge by the anaerobic sludge taken from bottom plant effluent treatment reactor, by seed sludge clean water totally to remove the residual waste water on its surface, then this seed sludge be inoculated in this reactor as anaerobic mud bed;

B, the waste water of low ratio of carbon to ammonium is added in raw water box, with the organism in waste water be carbon source, with SODIUMNITRATE for nitrogenous source, control reactor operating temperature by temperature control unit and remain on 34-36 DEG C, the pH value controlling waste water remains on 7.5-7.7, the water inlet flow velocity keeping waste water is 2.304L/d, and hydraulic detention time is 73h; Start reactor, waste water enters the cylindrical shell cavity of reactor under the effect of intake pump by the water-in of reactor bottom, upwards flow through the anaerobic mud bed of seed sludge composition, the mud generation anaerobic reaction of waste water and Sludge Bed, produce biogas and cause sludge stirring, the upwelling forming solid-liquid-gas mixing continues to rise, one baffle can tackle the mud granule in upwelling, complete preliminary solid-liquid separation, upwelling after preliminary solid-liquid separation continues to rise through the mud granule in secondary baffle plate second time separation upwelling, completes second time solid-liquid separation; There is gas-liquid separation in gas slowly-releasing district in upwelling subsequently, and the gas of separation enters air chamber district, and the liquid of separation enters settling region by recirculating zone, and in the liquid of separation, supernatant liquor is crossed peripheral weir and discharged by water outlet;

C, reactor run first 10 days, and nitrate of intaking in control raw water box is 0; 11-31 days, carbon-nitrogen ratio C/N of intaking in control raw water box is 75:1; 32-62 days, carbon-nitrogen ratio C/N of intaking in control raw water box is 15:1; 63-98 days, carbon-nitrogen ratio C/N of intaking in control raw water box is 7.5:1.

2. the method for methanation as claimed in claim 1 denitrification process low ratio of carbon to ammonium waste water simultaneously, is characterized in that: be provided with the water distributor being uniformly distributed waste water between the inherent anaerobic mud bed and described water-in of described cylindrical shell cavity.

3. the method for methanation as claimed in claim 1 denitrification process low ratio of carbon to ammonium waste water simultaneously, it is characterized in that: described temperature control unit is constant temperature water bath apparatus, it is peripheral that described constant temperature water bath apparatus is arranged at described cylindrical shell.

4. the method for methanation as claimed in claim 1 denitrification process low ratio of carbon to ammonium waste water simultaneously, is characterized in that: described cylindrical shell top is provided with thermometer, and described thermometer stretches in cylindrical shell cavity.

5. the method for the denitrification process low ratio of carbon to ammonium waste water simultaneously of the methanation as described in as arbitrary in Claims 1-4, it is characterized in that: described cylindrical shell is provided with multiple thief hole on different heights position, described thief hole connects stopple coupon, and described stopple coupon is provided with sampling valve.

6. the method for methanation as claimed in claim 5 denitrification process low ratio of carbon to ammonium waste water simultaneously, it is characterized in that: described gas outlet is connected to gas collection vessel by escape pipe, described escape pipe is provided with gas purifier and gas meter.

7. the method for methanation as claimed in claim 1 denitrification process low ratio of carbon to ammonium waste water simultaneously, it is characterized in that, described step C is: control water inlet total organic carbon TOC concentration constant, the interim concentration improving water inlet nitric nitrogen.

8. the method for methanation as claimed in claim 7 denitrification process low ratio of carbon to ammonium waste water simultaneously, it is characterized in that, described step C is specially: the total organic carbon TOC concentration that controls in 98 days that run at reactor to intake in raw water box remains 2250mg/L always; Reactor runs first 10 days, and nitrate of intaking in control raw water box is 0; 11-31 days, nitrate of intaking in control raw water box is 30mg/L; 32-62 days, nitrate of intaking in control raw water box is 150mg/L; 63-98 days, nitrate of intaking in control raw water box is 300mg/L.

9. the method for methanation as claimed in claim 6 denitrification process low ratio of carbon to ammonium waste water simultaneously, it is characterized in that, in described step B, the gas entering air chamber district enters escape pipe through gas outlet, through gas purifier, it is purified, then carry out gas flow measurement by gas meter, finally enter gas collection vessel by collection and confinement of gases; By strength of fluid survey meter, measurement of concetration is carried out to the supernatant liquor of discharging from water outlet.