CN113023882B

CN113023882B - Method and reactor for treating sewage with low carbon-nitrogen ratio

Info

Publication number: CN113023882B
Application number: CN202110267412.1A
Authority: CN
Inventors: 苏俊峰; 赵廷宝; 黄廷林; 王悦; 汪昭; 高文宇; 解雨萌; 张婉宁
Original assignee: Xian University of Architecture and Technology
Current assignee: Xian University of Architecture and Technology
Priority date: 2021-03-11
Filing date: 2021-03-11
Publication date: 2022-08-02
Anticipated expiration: 2041-03-11
Also published as: CN113023882A

Abstract

The invention discloses a method and a reactor for treating sewage with low carbon-nitrogen ratio, which comprises a reaction cavity and devices for feeding bacteria, adding a film, adding medicine, mixing, aerating and the like, and comprises the following steps: putting the sludge into a neutral enrichment medium EM for enrichment culture, and putting the collected enrichment sludge into a neutral DBM medium for periodic culture to obtain a biological agent; placing the biological agent in a neutral DBM culture medium and a water body to be treated, culturing in a mixed culture medium, and separating to obtain a biological aggregation membrane; the prepared biological aggregation film is added into a reactor, and efficient denitrification reaction is completed through three processes of a water inlet reaction process, a static sedimentation process and a drainage bacteria adding process by means of the characteristic that the biological aggregation film can efficiently denitrify sewage with low carbon-nitrogen ratio and the cooperation of devices such as aeration, bacteria adding and dosing. The reaction device can realize the high-efficiency denitrification of the sewage with low carbon-nitrogen ratio, has no nitrite accumulation, is not easy to lose strain immobilization, is simple to operate and manage and the like.

Description

Method and reactor for treating sewage with low carbon-nitrogen ratio

Technical Field

The invention relates to the field of treatment of sewage with a low carbon-nitrogen ratio, in particular to a method and a reactor for treating sewage with a low carbon-nitrogen ratio.

Background

With the rapid development of economy in China and the continuous improvement of the living standard of people, a large amount of domestic sewage, industrial wastewater and agricultural non-point source pollution carry nitrogen-containing substances to be discharged into a water body, so that the eutrophication of the water body is serious, and main pollution indexes are trinitrogen (nitrite nitrogen, nitrate nitrogen and ammonia nitrogen), total hardness sulfate and the like. The biological denitrification is the prior sewage denitrificationThe most economical and effective technology in nitrogen treatment comprises 2 processes of nitrification and denitrification. The traditional denitrification can realize complete denitrification only under the conditions of sufficient carbon source and complete anaerobism, has higher requirements on the environment, and the water quality of China is characterized by low carbon-nitrogen ratio, so that the denitrification is normally carried out by adding the carbon source, the treatment cost is increased, and a large amount of CO is generated ₂ And (3) discharging gas, and other researches show that the amount of added carbon source influences the nitrification and denitrification process, and nitrite nitrogen can be accumulated to cause incomplete nitrification when the carbon-nitrogen ratio is lower than the minimum value required by complete denitrification. Therefore, an economical and efficient method for treating the low carbon-nitrogen ratio sewage is needed.

The prior biological denitrification technology has the disadvantages of strict requirements, high cost, complex operation and difficult treatment of low-carbon nitrogen sewage.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method and a reactor for treating sewage with a low carbon-nitrogen ratio.

In order to realize the aim, the invention provides a method for treating sewage with low carbon-nitrogen ratio, which comprises the following steps:

step one, preparing a biological agent:

adding a neutral enrichment medium EM into the sludge sample, continuously replacing a culture solution to perform sludge periodic constant-temperature culture, and collecting the enriched sludge when the removal rate of nitrogen in the liquid culture solution reaches 75%;

transferring the enriched sludge into a neutral liquid DBM culture medium according to the mass ratio of 1:1.5-1:2, culturing at constant temperature until the removal rate of nitrogen in the liquid culture medium is more than 75%, and collecting a biological agent;

step two, preparing the biological aggregation membrane:

placing the biological agent into a mixed culture medium of a neutral liquid DBM culture medium and a water sample of a water body to be treated according to the mass ratio of 1:5-1:6, culturing at constant temperature, continuously replacing a mixed liquid of the neutral liquid DBM culture medium and the water sample of the water body to be treated, gradually increasing the proportion of the neutral liquid DBM culture medium and the water sample of the water body to be treated, and separating to obtain a biological aggregation membrane;

step three, the reactor operates:

adding the biological aggregation membrane into sewage, aerating, performing static settlement reaction, separating the biological aggregation membrane from sludge up and down on an aeration layer, and discharging supernatant and bottom sludge; then adding the biological agent into the residual sewage for reproduction to finish the low carbon nitrogen treatment of the sewage.

With respect to the above technical solutions, the present invention has a further preferable solution:

preferably, said neutral enrichment medium EM comprises: CH (CH) ₃ COONa、NaHCO ₃ 、NaNO ₃ 、KH ₂ PO ₄ 、MgCl ₂ 、CaCl ₂ 、PbCl ₂ HgCl and trace element solution I.

Preferably, the neutral enrichment medium EM comprises the following components in mass ratio of g/L: 0.40-0.60 g/L CH ₃ COONa，0.30-0.50 g/L NaHCO ₃ ，0.10-0.20 g/L NaNO ₃ ，0.08-0.12 g/L KH ₂ PO ₄ ，0.04-0.06 g/L MgCl ₂ ，0.04-0.06 g/L CaCl ₂ ，0.04-0.06 g/L PbCl ₂ 0.04-0.06 g/L of HgCl, 2-4 g/L of microelement solution I, and the pH is = 6.5-7.5;

the trace element solution I comprises the following components in percentage by mass in g/L: the method comprises the following steps: 1.0-1.4g/LEDTA, 0.15-0.25g/LZnSO ₄ ，0.08-0.12g/LMnCl ₂ ·4H ₂ O，0.30-0.50g/LMgSO ₄ ·7H ₂ O，0.30-0.50g/LCuSO ₄ ·5H ₂ O，0.35-0.45g/LCoCl ₂ ·6H ₂ O，0.35-0.45 g/LFeSO ₄ ·7H ₂ O，pH=6.5-7.5。

Preferably, the neutral liquid DBM culture medium comprises: CH (CH) ₃ COONa、NaNO ₃ 、KH ₂ PO ₄ 、MgCl ₂ 、PdCl ₂ HgCl and trace element solution II.

Preferably, the neutral liquid DBM culture medium comprises the following components in percentage by mass in g/L: 0.15-0.25g/LCH ₃ COONa，0.15-0.25g/LNaNO ₃ ，0.04-0.06g/LKH ₂ PO ₄ ，0.04-0.06g/LMgCl ₂ ，0.08-0.12g/LPdCl ₂ 0.08-0.12g/LHgCl, 2-4 g/L of microelement solution and 6.5-7.5 of pH value;

the microelement solution II comprises the following components in percentage by mass in g/L: 0.8-1.2g/L EDTA, 0.08-0.12g/L ZnSO ₄ ，0.08-0.12 g/L MnCl ₂ ·4H ₂ O，0.4-0.6 g/L MgSO ₄ ·7H ₂ O，0.4-0.6 g/L CuSO ₄ ·5H ₂ O，0.15-0.25 g/L CoCl ₂ ·6H ₂ O，0.4-0.6 g/L FeSO ₄ ·7H ₂ O，pH=6.5-7.5。

Preferably, in the first step, the sludge-enriched culture comprises: taking 6-8 days as a culture period, adding a new neutral enrichment culture medium EM after each culture period is finished, and shaking for 3-5 times per day at the rotating speed of 30-50 r/min, wherein each time lasts for 5-8 minutes;

the preparation of the biological agent comprises the following steps: transferring the enriched sludge to a neutral liquid DBM culture medium, culturing at a constant temperature of 25-30 ℃, and shaking for 3-5 times per day at the speed of 120-140 r/min, wherein each time lasts for 10-15 minutes; the DBM culture medium is replaced every 5-7 days, the concentration of the DBM culture medium which is replaced gradually is not changed, and NaNO is added ₃ The concentration of (c) is increased by 50%.

Preferably, in the second step, the preparation of the bio-aggregation membrane comprises:

21) mixing a neutral liquid DBM culture medium and a water sample of a water body to be treated according to a mass ratio of 4:1-3:1 to obtain a culture medium, placing a biological agent in the mixed culture medium, and culturing at a constant temperature of 25-30 ℃;

22) replacing the neutral liquid DBM culture medium once every 3-5 days, adding a mixed liquid of the neutral liquid DBM culture medium and the water sample to be treated according to the proportion of 3:1-2.5:1, and gradually increasing the proportion of the neutral liquid DBM culture medium and the water sample to be treated to 1:5-1: 6;

23) selecting a biological aggregation membrane with good growth and intact shape, and separating and taking out the biological aggregation membrane by adopting a filtration method.

Preferably, in the third step, the reactor operation comprises:

water feeding reaction: transferring the biological aggregation membrane into the first reaction cavity, and then introducing the water to be treated into the first reaction cavity; controlling aeration air inflow and alternately carrying out aeration;

and (3) a static settling process: the first reaction cavity stops aeration, and the biological aggregation film and sludge generated by the reaction are separated and deposited on an aeration layer at the bottom of the tank; the second reaction cavity repeatedly carries out water inlet reaction;

draining water and adding bacteria: discharging the water body and the sludge at the bottom after the reaction in the first reaction chamber respectively, adding a biological aggregation membrane and a biological microbial inoculum to the residual sewage in the reaction chamber, adding a buffer solution into the water to control the pH value of the liquid in the reaction chamber, breeding the biological microbial inoculum, and further performing low-carbon nitrogen treatment on the sewage; the second reaction cavity repeats the static settling process; the third reaction cavity repeatedly carries out water inlet reaction;

the second reaction chamber repeatedly discharges water and adds bacteria, the third reaction chamber repeatedly carries out the static sedimentation process and discharges water and adds bacteria, and the three reaction chambers circularly carry out sewage low-carbon nitrogen treatment.

Preferably, controlling the aeration air inflow to be 0.05L/S-0.08L/S, and alternately carrying out aeration for 40-45 min; the sludge is separated and deposited for 40-45min in the aeration layer at the bottom of the tank.

The invention further provides a reactor adopted by the method, which comprises three reaction tanks which are communicated in parallel, wherein a water inlet communicating pipe of each reaction tank is sequentially provided with a grating, a water inlet pump, a static mixer and a dosing device, the other pipeline of each reaction tank is provided with a bacterium dosing and dosing device communicated with the static mixer, the bottom of each reaction tank is provided with an aeration layer, and the bottom of the aeration layer is provided with a sludge discharge port; the side wall of the middle part of the reaction tank is provided with a water outlet.

The invention has the beneficial effects that:

1. the invention can realize the high-efficiency denitrification reaction in the environment with low carbon-nitrogen ratio, and solves the problems of low efficiency and nitrite accumulation of the traditional denitrification reaction under the condition with low carbon-nitrogen ratio. Bacterial organisms are adhered to each other by utilizing EPS secreted by the bacterial organisms to form an aggregation membrane with certain mechanical strength, so that a relatively closed anaerobic environment and EPS carbon source substances are provided for a denitrification process, the denitrification efficiency is high, and no by-product exists.

2. Lead element and mercury element are added into the EM culture medium, which is beneficial to improving the selectivity of the microbial inoculum for secreting the biological aggregation membrane. Lead element and mercury element are added into the DBM culture medium, which is beneficial to improving the capability and speed of the microbial inoculum for secreting the biological aggregation membrane.

3. Compared with the traditional activated sludge method, the method has the advantages that the biological aggregation membrane and the biological agent are further added into the residual sewage in the reaction cavity, the buffer solution is added into the water to control the pH value of the liquid in the reaction cavity, the propagation of the biological agent is controlled, and the low carbon nitrogen treatment of the sewage is further carried out; due to the existence of the biological aggregation membrane with certain mechanical strength and viscosity, a relatively fixed denitrification environment is provided for the microbial inoculum, the further input biological microbial inoculum can be solidified, and the loss rate is low.

4. The invention uses the traditional SBR process for reference, has the characteristics of small occupied area, simple equipment, strong stability, high activity, long service cycle, low energy consumption and the like, and distinguishes the traditional aeration tank with larger occupied area, the aeration system with high energy consumption and the sludge reflux system.

Drawings

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

FIG. 2(a) is a schematic diagram showing the effect of removing nitrate from the reactors of examples 1, 2 and 3;

FIG. 2(b) is a schematic diagram showing the effect of nitrite conversion in the reactors of examples 1, 2 and 3;

FIG. 3(a) is a schematic diagram showing the effect of nitrate removal in the reactors of examples 4, 5 and 6;

FIG. 3(b) is a schematic diagram showing the effect of nitrite conversion in the reactors of examples 4, 5 and 6;

FIGS. 4(a) and (b) are biological aggregation membrane physical diagrams.

Reference numbers in the figures: 1-grating, 2-water inlet pump, 3-static mixer, 4-dosing device, 5-gate valve, 6-exhaust hole, 7-reaction chamber, 8-biological gathering film, 9-bacteria dosing device, 10-blower, 11-aeration layer.

Detailed Description

The present invention will now be described in detail with reference to the drawings and specific embodiments, wherein the exemplary embodiments and descriptions of the present invention are provided to explain the present invention without limiting the invention thereto.

As shown in figure 1, the invention adopts a reactor for treating sewage with low carbon-nitrogen ratio to treat the sewage with low carbon-nitrogen ratio, and the reactor comprises: the device comprises three reaction tanks which are communicated in parallel, wherein a water inlet communicating pipeline of each reaction tank is sequentially provided with a grating 1, a water inlet pump 2, a static mixer 3 and a dosing device 4, the other pipeline of each reaction tank is provided with a bacterium dosing and dosing device 9 communicated with the static mixer 3, the bottom of each reaction tank is provided with an aeration layer 11, and the bottom of the aeration layer 11 is provided with a sludge discharge port; the side wall of the middle part of the reaction tank is provided with a water outlet. Wherein charge device is connected with 4 static mixer 3, has added biological gathering membrane 8 in the reaction chamber 7 of retort, and every reaction chamber 7 is connected with four gate valves 5, is intake gate valve, adds medicine gate valve, goes out water gate valve and row mud gate valve respectively. The fungus feeding and medicine adding device 9 is communicated with the three reaction tanks through a gate valve 5 communication pipeline, and the aeration layer 11 blows micro bubbles into the water body through being connected with the air blower 10. The top parts of the three reaction tanks are provided with exhaust holes 6 for exhausting N generated by the reaction ₂ And the like.

The method for treating the sewage with the low carbon-nitrogen ratio by adopting the reactor of the invention comprises the following steps:

step one, preparing a biological agent:

taking a proper sediment sample into a 500ml conical flask, adding 400-500ml enrichment medium EM into the conical flask, and covering a sealing film at the bottle mouth to provide an anaerobic environment. Shaking the conical flask to uniformly mix the system, placing the conical flask in a constant-temperature incubator (25-30 ℃) for culture, and collecting enriched sludge when the removal rate of nitrogen in liquid culture solution reaches 75%. Transferring the collected enriched sludge to a liquid DBM culture medium, carrying out constant-temperature culture, and collecting the biological agent precipitate.

The sludge culture takes 6-8 days as a culture period, after each culture period is finished, supernatant in the conical flask is slowly poured out, a new 400-500ml EM culture medium is added, a shaking table with the rotating speed of 30-50 rpm is adopted, shaking is carried out for 3-5 times every day, and each time is 5-8 minutes, so that nutrient substances capable of providing bacteria growth are ensured in the reactor. And (3) repeatedly replacing the culture medium until the removal rate of nitrogen in the liquid culture solution measured by the N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry and the ultraviolet spectrophotometry reaches over 75 percent, finishing sludge enrichment, and collecting sludge.

Wherein the formula of the enrichment medium EM is as follows: measured in mass concentration (g/L): 0.40-0.60 g/L CH ₃ COONa，0.30-0.50 g/L NaHCO ₃ ，0.10-0.20 g/L NaNO ₃ ，0.08-0.12 g/L KH ₂ PO ₄ ，0.04-0.06 g/L MgCl ₂ ，0.04-0.06 g/L CaCl ₂ ，0.04-0.06 g/L PbCl ₂ 0.04-0.06 g/L HgCl, 2-4 g/L microelement and pH = 6.5-7.5. The trace element solution I comprises: measured in mass concentration (g/L): 1.0-1.4g/L EDTA, 0.15-0.25g/L ZnSO ₄ ，0.08-0.12 g/L MnCl ₂ ·4H ₂ O，0.30-0.50 g/L MgSO ₄ ·7H ₂ O，0.30-0.50 g/L CuSO ₄ ·5H ₂ O，0.35-0.45 g/L CoCl ₂ ·6H ₂ O，0.35-0.45 g/L FeSO ₄ ·7H ₂ O，pH=6.5-7.5。

The preparation of the biological agent comprises the following steps: transferring the enriched sludge into a liquid DBM culture medium, wherein the enriched sludge and the DBM culture medium are mixed according to the mass ratio of 1:1.5-1:2, carrying out constant temperature culture at the temperature of 25-30 ℃, shaking for 3-5 times every day by using a shaking table with the rotating speed of 120-140 revolutions per minute, and each time lasts for 10-15 minutes; second, the DBM culture medium is replaced every 5-7 days, the concentration of the DBM culture medium which is replaced gradually is not changed, and NaNO is added ₃ The concentration of (A) is increased by 50%; and completing the preparation of the biological agent until the removal rate of nitrogen in the liquid culture solution is over 80 percent by using an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method.

Denitrification Basal Medium (DBM): in terms of mass concentrationMeter (g/L): 0.15-0.25g/L CH ₃ COONa，0.15-0.25 g/L NaNO ₃ ，0.04-0.06 g/L KH ₂ PO ₄ ，0.04-0.06 g/L MgCl ₂ ，0.08-0.12 g/L PdCl ₂ 0.08-0.12g/L HgCl, 2-4 g/L microelement II and 6.5-7.5 of pH value.

The microelement solution II comprises: measured in mass concentration (g/L): 0.8-1.2g/L EDTA, 0.08-0.12g/L ZnSO ₄ ，0.08-0.12 g/L MnCl ₂ ·4H ₂ O，0.4-0.6 g/L MgSO ₄ ·7H ₂ O，0.4-0.6 g/L CuSO ₄ ·5H ₂ O，0.15-0.25 g/L CoCl ₂ ·6H ₂ O，0.4-0.6 g/L FeSO ₄ ·7H ₂ O，pH=6.5-7.5。

Step two, preparing a biological aggregation membrane:

and (3) placing the biological agent obtained in the step one in a mixed culture medium of the DBM and the water sample of the water body to be treated, culturing under a constant temperature condition, and separating to obtain the biological aggregation membrane.

The preparation of the biological aggregation membrane comprises the following steps: mixing the DBM culture solution and the water sample of the water to be treated according to the ratio of 4:1-3:1, placing the biological agent obtained in the step one into the mixed culture medium, culturing at the constant temperature of 25-30 ℃, pouring out the supernatant in the culture medium every 3-5 days, and adding the mixed solution of the DBM culture solution and the water sample of the water to be treated according to the ratio of 3:1-2.5: 1. Gradually increasing the proportion of the DBM culture solution to the water sample of the water body to be treated to 1:5-1: 6. Selecting a biological aggregation membrane with good growth and intact shape, and separating and taking out the biological aggregation membrane by adopting a filtration method. The biological aggregation membrane is shown in figures 4(a) and (b).

Step three, operating the reactor:

the water inlet reaction process:

after 3-5L of biological aggregation membrane is transferred into the reaction cavity 1, opening a water inlet gate valve, closing a water outlet gate valve and a sludge discharge gate valve, and enabling water to be treated to enter the reaction cavity 1 after passing through the grating 1, the water inlet pump 2 and the static mixer 3; so that the water inflow accounts for 70-75% of the volume of the reaction cavity. Meanwhile, the blower 10 is started to blow micro bubbles into the reaction cavity 1 by the aeration layer 11, the air inflow is controlled to be 0.05L/S-0.08L/S, the working time of the blower 10 is 3-5min, the closing time is 5-7min, and the operation is carried out alternately in sequence. The reaction time in this step is 40-45 min.

(II) a static settling process:

after the reaction chamber 1 is finished, all gate valves and blowers of the reaction chamber 1 are closed, so that the reaction chamber 1 is subjected to a static settlement reaction. The biological aggregation film and the sludge generated by the reaction sink to the bottom of the tank, and simultaneously, due to the existence of the aeration layer, the biological aggregation film falls on the upper side of the aeration layer, the sludge can sink to the lower part of the aeration layer, and the two layers are separated. The reaction time in this step is 40-45 min. In the process, the water inlet gate valve of the reaction chamber 2 is opened, so that the reaction chamber 2 performs the reaction of the first step.

(III) draining and bacterium adding:

and after the second step of the reaction chamber 1 is finished, opening a water outlet gate valve and a sludge discharge gate valve of the reaction chamber 1 in sequence, so that the water body after reaction and the sludge at the bottom are discharged respectively. This process lasts for 10-12 min. And after the water outlet and the sludge discharge are completed, opening a dosing gate valve to enable the biological aggregation film and the microbial inoculum to be fed into the reaction cavity through a bacteria feeding and dosing device, and carrying out the process for 5-6 min. Thereafter, all gate valves of the reaction chamber 1 are closed, so that the microbial inoculum in the reaction chamber 1 is in a propagation state, and the process is 25-27 min. Step three takes 40-45min in total. In this process, the reaction chamber 2 performs the reaction of step two. And the reaction cavity 3 repeats the water inlet reaction in the step one.

The reaction cavity 2 is repeatedly drained and filled with bacteria, the reaction cavity 3 is repeatedly subjected to a static sedimentation process and drained and filled with bacteria, the three steps are all consumed for 40-45min, the three reaction cavities are sequentially subjected to a water inlet reaction process, a static sedimentation process and a drained and filled with bacteria, and the sewage low-carbon nitrogen treatment is circularly carried out.

The operation mechanism is as follows: the invention is based on the biological aggregation membrane and the traditional SBR process, the biological aggregation membrane and the microbial inoculum are added into the reaction cavity, and the denitrification reaction can be carried out by utilizing the characteristic that the microbial inoculum can carry out high-efficiency denitrification reaction in the sewage with low carbon-nitrogen ratio. In the sewage with low carbon-nitrogen ratio, the microbial inoculum utilizes EPS substances on the biological aggregation membrane as a carbon source in the denitrification process and utilizes the relatively closed anaerobic environment of the biological aggregation membrane, so that the efficient denitrification reaction is carried out, nitrate is removed, and no nitrite is accumulated. Meanwhile, because the biological aggregation membrane has certain mechanical strength, compared with the traditional activated sludge method, the method ensures that the microbial inoculum is solidified and reduces the loss rate of the microbial inoculum. By referring to the traditional SBR process, the reaction process of the reactor of the invention is respectively and continuously carried out with a water inlet reaction process, a static sedimentation process and a water drainage and bacterium adding process. Meanwhile, aeration equipment is adopted, and the time and the strength of aeration are controlled, so that the biological aggregation membrane can move up and down in the water body to fully contact and react with the water body. The water inlet is provided with a static mixer and a grid, the grid is used for removing impurities in the inlet water and preventing the biological aggregation membrane from being damaged, and the static mixer is used for mixing the buffer solution and the inlet water and controlling the pH value of the liquid in the reaction cavity. The bacteria feeding and dosing device conveys the biological aggregation film and the microbial inoculum to the reaction cavity to maintain a certain biological dosage in the reaction cavity.

The reaction related to the denitrification process is as follows

2NO ₃ ^- + 10e ^- +12H ⁺ → N ₂ +6H ₂ O；

Under the action of denitrifying bacteria, NO ₃ ^- Is reduced to N ₂ Realizing the high-efficiency removal of nitrate.

The invention is further illustrated by the following specific examples.

Example 1:

in the embodiment, the sewage to be treated comes from domestic sewage of a certain school in the city of western city, shaanxi province, and the water body is treated according to the technical scheme of the invention. In order to ensure good treatment effect, the reaction method and the reactor have the following operation steps:

1. preparing a biological agent:

a sample of the appropriate sediment was taken in a 10L Erlenmeyer flask, to which 7L of enrichment medium EM was added, and the mouth of the flask was covered with a sealing membrane to provide an anaerobic environment. Shaking the conical flask to uniformly mix the system, placing the conical flask in a constant-temperature incubator (25 ℃) for culture, taking 8 days as a culture period, slowly pouring out supernatant in the conical flask after each culture period is finished, adding a new 7L EM culture medium, shaking the conical flask for 5 times every day by using a shaking table with the rotating speed of 30 revolutions per minute, and shaking for 6 minutes every time to ensure that nutrient substances capable of allowing bacteria to grow exist in the reactor. And (3) repeatedly replacing the culture solution until the removal rate of nitrogen in the liquid culture solution is more than 80% by using an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method, and collecting sludge.

And transferring the collected enriched sludge to a liquid DBM culture medium, carrying out constant-temperature culture, and collecting the biological agent. The preparation of the biological agent comprises the following steps: firstly, transferring enriched sludge into a liquid DBM culture medium, wherein the enriched sludge and the DBM culture medium are mixed according to the mass ratio of 1:1.5, carrying out constant-temperature culture at 25 ℃, and shaking for 5 times a day and 12 minutes each time by using a shaking table with the rotating speed of 130 revolutions per minute; second, the DBM medium is replaced every 6 days, the concentration of the DBM medium which is replaced gradually is not changed, and NaNO is added ₃ The concentration of the microbial inoculum is increased by 50 percent gradually until the removal rate of nitrogen in the liquid culture solution is over 80 percent by using an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method, and the preparation of the biological microbial inoculum is finished.

The formula of the Enrichment Medium (EM) is as follows: measured in terms of mass concentration (g/L), 0.40CH ₃ COONa，0.45NaHCO ₃ ，0.15NaNO ₃ ，0.12KH ₂ PO ₄ ，0.06MgCl ₂ ，0.05CaCl ₂ ，0.06PbCl ₂ 0.05 HgCl, trace element I3 g/L, pH = 6.5.

The trace element solution I comprises: measured by mass concentration (g/L), 1.4EDTA, 0.15ZnSO ₄ ，0.08MnCl ₂ ·4H ₂ O，0.45MgSO ₄ ·7H ₂ O，0.30CuSO ₄ ·5H ₂ O，0.40CoCl ₂ ·6H ₂ O，0.40 FeSO ₄ ·7H ₂ O，pH=6.5。

A Denitrification Basal Medium (DBM) comprising: measured in terms of mass concentration (g/L), 0.15CH ₃ COONa，0.20NaNO ₃ ，0.06KH ₂ PO ₄ ，0.04MgCl ₂ ，0.10PbCl ₂ 0.09HgCl, 3mL of microelement II, and pH = 6.5.

The microelement solution II comprises: measured by mass concentration (g/L), 0.8EDTA, 0.10ZnSO ₄ ，0.11MnC ₂ ·4H ₂ O，0.40MgSO ₄ ·7H ₂ O，0.60CuSO ₄ ·5H ₂ O，0.15CoCl ₂ ·6H ₂ O，0.50 FeSO ₄ ·7H ₂ O，pH=6.5。

2. Preparing a biological aggregation membrane: mixing the DBM culture solution and the water sample of the water body to be treated according to the proportion of 3:1, placing the obtained biological agent into the mixed culture medium, placing the mixed culture medium at the constant temperature of 25 ℃ for culturing at intervals of 4 days, pouring out supernatant in the culture medium, and adding the mixed solution of the DBM culture solution and the water sample of the water body to be treated according to the proportion of 3: 1. Gradually increasing the proportion of the DBM culture solution to the water sample of the water body to be treated to 1: 6. Selecting a biological aggregation membrane with good growth and intact shape, and separating and taking out the biological aggregation membrane by adopting a filtration method.

4. The operation of the reactor: the sewage treatment reactor based on the bacterial biological aggregation membrane is adopted, the prepared biological aggregation membrane is added into a reaction cavity by an adding device, about 3L of biological aggregation membrane is added into the reaction cavity, and a microbial inoculum is added into the reaction cavity at the rate of 0.5L/h. And the aeration system is started, so that the biological aggregation membrane continuously floats upwards and sinks, and can be fully contacted with sewage in the reaction cavity. In the reaction cavity, the biological aggregation membrane enables the denitrifying bacteria to perform efficient denitrification reaction by utilizing the EPS substances and the relatively closed anaerobic environment.

The reactor was run as follows:

the water inlet reaction process:

after 3L of biological aggregation membrane is transferred into the reaction chamber 1, opening a water inlet gate valve, closing a water outlet gate valve and a sludge discharge gate valve, and enabling water to be treated to enter the reaction chamber 1 after passing through the grating 1, the water inlet pump 2 and the static mixer 3; so that the water intake accounts for 75% of the volume of the reaction chamber. Meanwhile, the blower 10 is started to blow micro bubbles into the reaction chamber 1 from the aeration layer 11, the air inflow is controlled to be 0.06L/S, the working time of the blower 10 is 4min, the closing time is 7min, and the operation is carried out alternately in sequence. The reaction time for this step was 40 min.

(II) a static settling process:

after the reaction chamber 1 is finished, all gate valves and blowers of the reaction chamber 1 are closed, so that the reaction chamber 1 is subjected to a static settlement reaction. The biological aggregation film and the sludge generated by the reaction sink to the bottom of the tank, and simultaneously, due to the existence of the aeration layer, the biological aggregation film falls on the upper side of the aeration layer, the sludge can sink to the lower part of the aeration layer, and the two layers are separated. The reaction time for this step was 40 min. In the process, the water inlet gate valve of the reaction chamber 2 is opened, so that the reaction chamber 2 performs the reaction of the first step.

(III) draining and bacterium adding:

and after the second step of the reaction chamber 1 is finished, opening a water outlet gate valve and a sludge discharge gate valve of the reaction chamber 1 in sequence, so that the water body after reaction and the sludge at the bottom are discharged respectively. This process lasted 12 min. After the water outlet and the sludge discharge are completed, a dosing gate valve is opened, so that the biological aggregation film and the microbial inoculum are fed into the reaction cavity through a bacteria feeding and dosing device, and the process is carried out for 6 min. Thereafter, all gate valves of the reaction chamber 1 are closed, so that the microbial inoculum in the reaction chamber 1 is in a propagation state, and the process is 25 min. Step three took a total of 40 min. In this process, the reaction chamber 2 performs the reaction of the second step. And the reaction cavity 3 repeats the water inlet reaction in the step one.

From FIGS. 2(a) and 2(b), it can be seen that the reactor operated well throughout the entire operating cycle, with an average nitrate removal rate of 93.28%, an average nitrite content of 0.12 mg/L in the reactor effluent, and no nitrite accumulation.

Example 2:

1. preparing a biological agent:

a sample of the appropriate sediment was taken in a 10L Erlenmeyer flask, to which 8L of enrichment medium EM was added, and the mouth of the flask was covered with a sealing membrane to provide an anaerobic environment. Shaking the conical flask to uniformly mix the system, placing the conical flask in a constant-temperature incubator (28 ℃) for culture, taking 7 days as a culture period, slowly pouring out supernatant in the conical flask after each culture period is finished, adding a new 8L EM culture medium, shaking the conical flask for 4 times every day by using a shaking table with the rotating speed of 40 revolutions per minute, and shaking for 8 minutes every time to ensure that nutrient substances capable of allowing bacteria to grow exist in the reactor. And (3) repeatedly replacing the culture solution until the removal rate of nitrogen in the liquid culture solution is more than 80% by using an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method, and collecting sludge.

And transferring the collected enriched sludge to a liquid DBM culture medium, carrying out constant-temperature culture, and collecting the biological agent. The preparation of the biological agent comprises the following steps: firstly, transferring enriched sludge into a liquid DBM culture medium, wherein the enriched sludge and the DBM culture medium are mixed according to the mass ratio of 1:2, carrying out constant-temperature culture at the temperature of 28 ℃, and shaking for 13 minutes each time 4 times a day by using a shaking table with the rotating speed of 130 revolutions per minute; second, the DBM medium is replaced every 6 days, the concentration of the DBM medium which is replaced gradually is not changed, and NaNO is added ₃ The concentration of (a) is increased by 50%; and completing the preparation of the biological agent until the removal rate of nitrogen in the liquid culture solution is over 80 percent by using an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method.

The formula of the Enrichment Medium (EM) is as follows: measured in terms of mass concentration (g/L), 0.55CH ₃ COONa，0.50NaHCO ₃ ，0.20NaNO ₃ ，0.08KH ₂ PO ₄ ，0.06MgCl ₂ ，0.06CaCl ₂ ，0.06PbCl ₂ 0.04HgCl, 3mL of trace element I, and pH =7.

The trace element solution I comprises: measured by mass concentration (g/L), 1.2EDTA, 0.25ZnSO ₄ ，0.08MnCl ₂ ·4H ₂ O，0.50MgSO ₄ ·7H ₂ O，0.35CuSO ₄ ·5H ₂ O，0.45CoCl ₂ ·6H ₂ O，0.35 FeSO ₄ ·7H ₂ O，pH=7。

Basic culture for denitrificationThe base (DBM) comprises: measured in terms of mass concentration (g/L), 0.20CH ₃ COONa，0.25NaNO ₃ ，0.06KH ₂ PO ₄ ，0.05MgCl ₂ ，0.11PbCl ₂ 0.08HgCl, trace element ii 2mL, pH =7.

The microelement solution II comprises: measured by mass concentration (g/L), 1.0EDTA, 0.12ZnSO ₄ ，0.11MnC ₂ ·4H ₂ O，0.40MgSO ₄ ·7H ₂ O，0.50CuSO ₄ ·5H ₂ O，0.20CoCl ₂ ·6H ₂ O，0.50 FeSO ₄ ·7H ₂ O，pH=7。

2. Preparing a biological aggregation membrane: mixing DBM culture solution and the water sample of the water to be treated according to the proportion of 3.5:1, placing the obtained biological agent into the mixed culture medium, culturing at the constant temperature of 28 ℃, pouring out supernatant in the culture medium every 5 days, and adding the mixed solution of the DBM culture solution and the water sample of the water to be treated according to the proportion of 3: 1. Gradually increasing the proportion of the DBM culture solution to the water sample of the water body to be treated to 1: 6. Selecting a biological aggregation membrane with good growth and intact shape, and separating and taking out the biological aggregation membrane by adopting a filtration method.

4. The operation of the reactor: the sewage treatment reactor based on the bacterial biological aggregation membrane is adopted, the prepared biological aggregation membrane is added into a reaction cavity by an adding device, about 4L of biological aggregation membrane is added into the reaction cavity, and a microbial inoculum is added into the reaction cavity at the rate of 0.4L/h. And the aeration system is started, so that the biological aggregation membrane continuously floats upwards and sinks, and can be fully contacted with sewage in the reaction cavity. In the reaction cavity, the biological aggregation membrane enables the denitrifying bacteria to perform efficient denitrification reaction by utilizing the EPS substances and the relatively closed anaerobic environment.

The reactor was run as follows:

the water inlet reaction process:

after 4L of biological aggregation membrane is transferred into the reaction chamber 1, a water inlet gate valve is opened, a water outlet gate valve and a sludge discharge gate valve are closed, and water to be treated enters the reaction chamber 1 after passing through the grating 1, the water inlet pump 2 and the static mixer 3; so that the water intake accounts for 70% of the volume of the reaction chamber. Meanwhile, the blower 10 is started to blow micro bubbles into the reaction chamber 1 by the aeration layer 11, the air inflow is controlled to be 0.05L/S, the working time of the blower 10 is 5min, the closing time is 5min, and the operation is carried out alternately in sequence. The reaction time for this step was 45 min.

(II) a static settling process:

after the reaction chamber 1 is finished, all gate valves and blowers of the reaction chamber 1 are closed, so that the reaction chamber 1 is subjected to a static settlement reaction. The biological aggregation film and the sludge generated by the reaction sink to the bottom of the tank, and simultaneously, due to the existence of the aeration layer, the biological aggregation film falls on the upper side of the aeration layer, the sludge can sink to the lower part of the aeration layer, and the two layers are separated. The reaction time for this step was 42 min. In the process, the water inlet gate valve of the reaction chamber 2 is opened, so that the reaction chamber 2 performs the reaction of the first step.

(III) draining and bacterium adding:

and after the second step of the reaction chamber 1 is finished, opening a water outlet gate valve and a sludge discharge gate valve of the reaction chamber 1 in sequence, so that the water body after reaction and the sludge at the bottom are discharged respectively. This process lasted 10 min. After the water outlet and the sludge discharge are completed, a dosing gate valve is opened, so that the biological aggregation film and the microbial inoculum are fed into the reaction cavity through a bacteria feeding and dosing device, and the process is carried out for 6 min. Thereafter, all gate valves of the reaction chamber 1 are closed, so that the microbial inoculum in the reaction chamber 1 is in a propagation state, and the process is 27 min. Step three took a total of 40 min. In this process, the reaction chamber 2 performs the reaction of the second step. And the reaction cavity 3 repeats the water inlet reaction in the step one.

From FIGS. 2(a) and 2(b), it can be seen that the reactor operated well throughout the entire operating cycle, with an average nitrate removal rate of 95.88%, an average nitrite content of 0.09 mg/L in the reactor effluent, and no nitrite accumulation.

Example 3:

1. sludge enrichment domestication and biological agent preparation: a sample of the appropriate sediment was taken in a 10L Erlenmeyer flask, to which 9L of enrichment medium EM was added, and the mouth of the flask was covered with a sealing membrane to provide an anaerobic environment. Shaking the conical flask to uniformly mix the system, placing the conical flask in a constant-temperature incubator (30 ℃) for culturing, taking 6 days as a culture period, slowly pouring out supernatant in the conical flask after each culture period is finished, adding a new 8L EM culture medium, shaking the conical flask for 3 times every day by adopting a shaking table with the rotating speed of 50 revolutions per minute, and shaking for 5 minutes every time to ensure that nutrient substances capable of allowing bacteria to grow exist in the reactor. And (3) repeatedly replacing the culture solution until the removal rate of nitrogen in the liquid culture solution is over 80 percent by using an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method, finishing sludge enrichment, and collecting sludge.

And transferring the collected enriched sludge to a liquid DBM culture medium, carrying out constant-temperature culture, and collecting the biological agent. The preparation of the biological agent comprises the following steps: firstly, transferring enriched sludge into a liquid DBM culture medium, wherein the enriched sludge and the DBM culture medium are mixed according to the mass ratio of 1:2, carrying out constant-temperature culture at the temperature of 30 ℃, and shaking for 3 times a day and 15 minutes each time by using a shaking table with the rotating speed of 140 revolutions per minute; secondly, replacing the DBM culture medium every 5 days, keeping the concentration of the sequentially replaced DBM culture medium unchanged, and increasing the concentration of NaNO3 by 50%; and completing the preparation of the biological agent until the removal rate of nitrogen in the liquid culture solution is over 80 percent by using an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method.

The formula of the Enrichment Medium (EM) is as follows: measured in terms of mass concentration (g/L), 0.60CH ₃ COONa，0.30NaHCO ₃ ，0.10NaNO ₃ ，0.12KH ₂ PO ₄ ，0.04MgCl ₂ ，0.05CaCl ₂ ，0.06PbCl ₂ 0.04HgCl, trace element I4 mL, pH = 7.5.

The trace element solution I comprises: measured by mass concentration (g/L), 1.0EDTA, 0.20ZnSO ₄ ，0.10MnCl ₂ ·4H ₂ O，0.40MgSO ₄ ·7H ₂ O，0.50CuSO ₄ ·5H ₂ O，0.40CoCl ₂ ·6H ₂ O，0.35 FeSO ₄ ·7H ₂ O，pH=7.5。

A Denitrification Basal Medium (DBM) comprising: measured in terms of mass concentration (g/L), 0.25CH ₃ COONa，0.15NaNO ₃ ，0.04KH ₂ PO ₄ ，0.06MgCl ₂ ，0.08PbCl ₂ 0.10HgCl, trace element ii 4mL, pH = 7.5.

The microelement solution II comprises: measured by mass concentration (g/L), 1.2EDTA, 0.10ZnSO ₄ ，0.08MnC ₂ ·4H ₂ O，0.40MgSO ₄ ·7H ₂ O，0.60CuSO ₄ ·5H ₂ O，0.20CoCl ₂ ·6H ₂ O，0.50 FeSO ₄ ·7H ₂ O，pH=7.5。

2. Preparing a biological aggregation membrane: mixing DBM culture solution and the water sample of the water to be treated according to the ratio of 4:1, placing the obtained biological agent into the mixed culture medium, placing the mixed culture medium at the constant temperature of 30 ℃ for culturing, pouring out supernatant in the culture medium every 3 days, and adding the mixed solution of the DBM culture solution and the water sample of the water to be treated according to the ratio of 2.5: 1. Gradually increasing the proportion of the DBM culture solution to the water sample of the water body to be treated to 1: 6. Selecting a biological aggregation membrane with good growth and intact shape, and separating and taking out the biological aggregation membrane by adopting a filtration method.

4. The operation of the reactor: the sewage treatment reactor based on the bacterial biological aggregation membrane is adopted, the prepared biological aggregation membrane is added into a reaction cavity by an adding device, about 5L of biological aggregation membrane is added into the reaction cavity, and a microbial inoculum is added into the reaction cavity at the rate of 0.3L/h. And the aeration system is started, so that the biological aggregation membrane continuously floats upwards and sinks, and can be fully contacted with sewage in the reaction cavity. In the reaction cavity, the biological aggregation membrane enables the denitrifying bacteria to perform efficient denitrification reaction by utilizing the EPS substances and the relatively closed anaerobic environment.

The reactor was run as follows:

the water inlet reaction process:

after 5L of biological aggregation membrane is transferred into the reaction chamber 1, opening a water inlet gate valve, closing a water outlet gate valve and a sludge discharge gate valve, and enabling water to be treated to enter the reaction chamber 1 after passing through the grating 1, the water inlet pump 2 and the static mixer 3; so that the water intake accounts for 72% of the volume of the reaction chamber. Meanwhile, the blower 10 is started to blow micro bubbles into the reaction chamber 1 by the aeration layer 11, the air inflow is controlled to be 0.07L/S, the working time of the blower 10 is 3min, the closing time is 6min, and the operation is carried out alternately in sequence. The reaction time for this step was 42 min.

(II) a static settling process:

after the reaction chamber 1 is finished, all gate valves and blowers of the reaction chamber 1 are closed, so that the reaction chamber 1 is subjected to a static settlement reaction. The biological aggregation film and the sludge generated by the reaction sink to the bottom of the tank, and simultaneously, due to the existence of the aeration layer, the biological aggregation film falls on the upper side of the aeration layer, the sludge can sink to the lower part of the aeration layer, and the two layers are separated. The reaction time for this step was 45 min. In this process, the water inlet gate valve of the reaction chamber 2 is opened, so that the reaction chamber 2 performs the reaction of the first step.

(III) draining and bacterium adding:

and after the second step of the reaction chamber 1 is finished, opening a water outlet gate valve and a sludge discharge gate valve of the reaction chamber 1 in sequence, so that the water body after reaction and the sludge at the bottom are discharged respectively. This process lasted 10 min. And after the water outlet and the sludge discharge are completed, opening a dosing gate valve to enable the biological aggregation film and the microbial inoculum to be fed into the reaction cavity through a bacteria feeding and dosing device, and carrying out the process for 5 min. Thereafter, all gate valves of the reaction chamber 1 are closed, so that the microbial inoculum in the reaction chamber 1 is in a propagation state, and the process is 26 min. Step three took a total of 43 min. In this process, the reaction chamber 2 performs the reaction of the second step. And the reaction cavity 3 repeats the water inlet reaction in the step one.

From FIGS. 2(a) and 2(b), it can be seen that the reactor operated well throughout the entire operating cycle, with an average nitrate removal rate of 95.31%, an average nitrite content of 0.10 mg/L in the reactor effluent, and no nitrite accumulation.

Example 4:

in this example, the wastewater to be treated is the wastewater from a certain wastewater treatment plant in Western Aphan, Shaanxi province, and the water body is treated according to the technical scheme of the invention. In order to ensure good treatment effect, the reaction method and the reactor have the following operation steps:

1. sludge enrichment domestication and biological agent preparation: a sample of the appropriate sediment was taken in a 10L Erlenmeyer flask, to which 7.5L of enrichment medium EM was added, and the mouth of the flask was capped with a sealing membrane to provide an anaerobic environment. Shaking the conical flask to uniformly mix the system, placing the conical flask in a constant-temperature incubator (26 ℃) for culturing, taking 6 days as a culture period, slowly pouring out the supernatant in the conical flask after each culture period is finished, adding a new 7.5L EM culture medium, shaking the conical flask for 3 times every day by adopting a shaking table with the rotating speed of 40 revolutions per minute, and ensuring that nutrient substances capable of allowing bacteria to grow exist in the reactor for 6 minutes every time. And (3) repeatedly replacing the culture solution until the removal rate of nitrogen in the liquid culture solution measured by an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method reaches more than 80%, completing sludge enrichment, and collecting sludge.

And transferring the collected enriched sludge to a liquid DBM culture medium, carrying out constant-temperature culture, and collecting the biological agent. The preparation of the biological agent comprises the following steps: firstly, transferring enriched sludge into a liquid DBM culture medium, wherein the enriched sludge and the DBM culture medium are mixed according to the mass ratio of 1:1.5, carrying out constant-temperature culture at the temperature of 30 ℃, and shaking for 12 minutes each time for 6 times a day by using a shaking table with the rotating speed of 120 revolutions per minute; secondly, replacing the DBM culture medium every 5 days, keeping the concentration of the sequentially replaced DBM culture medium unchanged, and increasing the concentration of NaNO3 by 50%; and completing the preparation of the biological agent until the removal rate of nitrogen in the liquid culture solution is over 80 percent by using an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method.

Preparation of Enrichment Medium (EM)The method comprises the following steps: measured in terms of mass concentration (g/L), 0.45CH ₃ COONa，0.50NaHCO ₃ ，0.15NaNO ₃ ，0.12KH ₂ PO ₄ ，0.06MgCl ₂ ，0.06CaCl ₂ ，0.04PbCl ₂ 0.04HgCl, trace element I2 mL, pH = 6.5.

The trace element solution I comprises: measured by mass concentration (g/L), 1.2EDTA, 0.15ZnSO ₄ ，0.12MnCl ₂ ·4H ₂ O，0.40MgSO ₄ ·7H ₂ O，0.50CuSO ₄ ·5H ₂ O，0.35CoCl ₂ ·6H ₂ O，0.40 FeSO ₄ ·7H ₂ O，pH=6.5。

A Denitrification Basal Medium (DBM) comprising: measured in mass concentration (g/L): 0.25CH ₃ COONa，0.20NaNO ₃ ，0.05KH ₂ PO ₄ ，0.06MgCl ₂ ，0.12PbCl ₂ 0.08HgCl, trace element ii 2mL, pH = 6.5.

The microelement solution II comprises: measured by mass concentration (g/L), 1.0EDTA, 0.08ZnSO ₄ ，0.10MnC ₂ ·4H ₂ O，0.50MgSO ₄ ·7H ₂ O，0.50CuSO ₄ ·5H ₂ O，0.25CoCl ₂ ·6H ₂ O，0.4FeSO ₄ ·7H ₂ O，pH=6.5。

2. Preparing a biological aggregation membrane: mixing the DBM culture solution and the water sample of the water body to be treated according to the proportion of 3:1, placing the obtained biological agent into the mixed culture medium, placing the mixed culture medium at the constant temperature of 26 ℃, culturing at constant temperature every 3 days, pouring out supernatant in the culture medium, and adding the mixed solution of the DBM culture solution and the water sample of the water body to be treated according to the proportion of 3: 1. Gradually increasing the proportion of the DBM culture solution to the water sample of the water body to be treated to 1: 5. Selecting a biological aggregation membrane with good growth and intact shape, and separating and taking out the biological aggregation membrane by adopting a filtration method.

4. The operation of the reactor: the sewage treatment reactor based on the bacterial biological aggregation membrane is adopted, the prepared biological aggregation membrane is added into a reaction cavity by an adding device, about 3.5L of biological aggregation membrane is added into the reaction cavity, and a microbial inoculum is added into the reaction cavity at the rate of 0.4L/h. And the aeration system is started, so that the biological aggregation membrane continuously floats upwards and sinks, and can be fully contacted with sewage in the reaction cavity. In the reaction cavity, the biological aggregation membrane enables the denitrifying bacteria to perform efficient denitrification reaction by utilizing the EPS substances and the relatively closed anaerobic environment.

The reactor was run as follows:

the water inlet reaction process:

after 3L of biological aggregation membrane is transferred into the reaction chamber 1, opening a water inlet gate valve, closing a water outlet gate valve and a sludge discharge gate valve, and enabling water to be treated to enter the reaction chamber 1 after passing through the grating 1, the water inlet pump 2 and the static mixer 3; so that the water inflow accounts for 73% of the volume of the reaction chamber. Meanwhile, the blower 10 is started to blow micro bubbles into the reaction chamber 1 from the aeration layer 11, the air inflow is controlled to be 0.06L/S, the working time of the blower 10 is 4min, the closing time is 7min, and the operation is carried out alternately in sequence. The reaction time for this step was 43 min.

(II) a static settling process:

after the reaction chamber 1 is finished, all gate valves and blowers of the reaction chamber 1 are closed, so that the reaction chamber 1 is subjected to a static settlement reaction. The biological aggregation film and the sludge generated by the reaction sink to the bottom of the tank, and simultaneously, due to the existence of the aeration layer, the biological aggregation film falls on the upper side of the aeration layer, the sludge can sink to the lower part of the aeration layer, and the two layers are separated. The reaction time for this step was 43 min. In the process, the water inlet gate valve of the reaction chamber 2 is opened, so that the reaction chamber 2 performs the reaction of the first step.

(III) draining and bacterium adding:

and after the second step of the reaction chamber 1 is finished, opening a water outlet gate valve and a sludge discharge gate valve of the reaction chamber 1 in sequence, so that the water body after reaction and the sludge at the bottom are discharged respectively. This process lasted 11 min. After the water outlet and the sludge discharge are completed, a dosing gate valve is opened, so that the biological aggregation film and the microbial inoculum are fed into the reaction cavity through a bacteria feeding and dosing device, and the process is carried out for 6 min. Thereafter, all gate valves of the reaction chamber 1 are closed, so that the microbial inoculum in the reaction chamber 1 is in a propagation state, and the process is 27 min. Step three took 41min in total. In this process, the reaction chamber 2 performs the reaction of the second step. And the reaction cavity 3 repeats the water inlet reaction in the step one.

From FIGS. 3(a) and 3(b), it can be seen that the reactor operated well throughout the entire operating period, the average nitrate removal rate was 93.18%, the average nitrite content in the reactor effluent was 0.13 mg/L, and no nitrite accumulation occurred.

Example 5:

1. sludge enrichment domestication and biological agent preparation: a sample of the appropriate sediment was taken in a 10L Erlenmeyer flask, to which 8.5L of enrichment medium EM was added, and the mouth of the flask was capped with a sealing membrane to provide an anaerobic environment. Shaking the conical flask to uniformly mix the system, placing the conical flask in a constant-temperature incubator (28 ℃) for culture, taking 7 days as a culture period, slowly pouring out supernatant in the conical flask after each culture period is finished, adding a new 8.5L EM culture medium, adopting a shaking table with the rotating speed of 45 revolutions per minute, shaking for 4 times every day, and each time for 8 minutes to ensure that nutrient substances capable of providing bacteria growth exist in the reactor. And (3) repeatedly replacing the culture solution until the removal rate of nitrogen in the liquid culture solution measured by an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method reaches more than 80%, completing sludge enrichment, and collecting sludge.

And transferring the collected enriched sludge to a liquid DBM culture medium, carrying out constant-temperature culture, and collecting the biological agent. The preparation of the biological agent comprises the following steps: firstly, transferring enriched sludge into a liquid DBM culture medium, wherein the enriched sludge and the DBM culture medium are mixed according to the mass ratio of 1:2, carrying out constant-temperature culture at the temperature of 30 ℃, and shaking for 14 minutes each time 4 times a day by using a shaking table with the rotating speed of 135 revolutions per minute; second, change every 6 daysOnce DBM culture medium, gradually changed DBM culture medium concentration is unchanged, NaNO ₃ The concentration of (a) is increased by 50%; and completing the preparation of the biological agent until the removal rate of nitrogen in the liquid culture solution is over 80 percent by using an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method.

The formula of the Enrichment Medium (EM) is as follows: measured in terms of mass concentration (g/L), 0.50CH ₃ COONa，0.40NaHCO ₃ ，0.10NaNO ₃ ，0.11KH ₂ PO ₄ ，0.05MgCl ₂ ，0.04CaCl ₂ ，0.05PbCl ₂ 0.04HgCl, 3mL of trace element I, and pH =7.

The trace element solution I comprises: measured by mass concentration (g/L), 1.2EDTA, 0.25ZnSO ₄ ，0.08MnCl ₂ ·4H ₂ O，0.30MgSO ₄ ·7H ₂ O，0.40CuSO ₄ ·5H ₂ O，0.35Cl ₂ ·6H ₂ O，0.45 FeSO ₄ ·7H ₂ O，pH=7。

A Denitrification Basal Medium (DBM) comprising: measured in terms of mass concentration (g/L), 0.20CH ₃ COONa，0.25NaNO ₃ ，0.05KH ₂ PO ₄ ，0.08MgCl ₂ ，0.12PbCl ₂ 0.12HgCl, trace element ii 3mL, pH =7.

The microelement solution II comprises: measured by mass concentration (g/L), 1.1EDTA, 0.10ZnSO ₄ ，0.12MnC ₂ ·4H ₂ O，0.60MgSO ₄ ·7H ₂ O，0.40CuSO ₄ ·5H ₂ O，0.25CoCl ₂ ·6H ₂ O，0.40 FeSO ₄ ·7H ₂ O，pH=7。

4. The operation of the reactor: the sewage treatment reactor based on the bacterial biological aggregation membrane is adopted, the prepared biological aggregation membrane is added into a reaction cavity by an adding device, about 4.5L of biological aggregation membrane is added into the reaction cavity, and a microbial inoculum is added into the reaction cavity at the rate of 0.45L/h. And the aeration system is started, so that the biological aggregation membrane continuously floats upwards and sinks, and can be fully contacted with sewage in the reaction cavity. In the reaction cavity, the biological aggregation membrane enables the denitrifying bacteria to perform efficient denitrification reaction by utilizing the EPS substances and the relatively closed anaerobic environment.

The reactor was run as follows:

the water inlet reaction process:

after 5L of biological aggregation membrane is transferred into the reaction chamber 1, opening a water inlet gate valve, closing a water outlet gate valve and a sludge discharge gate valve, and enabling water to be treated to enter the reaction chamber 1 after passing through the grating 1, the water inlet pump 2 and the static mixer 3; so that the water intake is 74% of the reaction chamber volume. Meanwhile, the blower 10 is started to make the aeration layer 11 blow micro bubbles into the reaction chamber 1, the air inflow is controlled to be 0.07L/S, the working time of the blower 10 is 4min, the closing time is 5min, and the operation is carried out alternately in sequence. The reaction time for this step was 43 min.

(II) a static settling process:

after the reaction chamber 1 is finished, all gate valves and blowers of the reaction chamber 1 are closed, so that the reaction chamber 1 is subjected to a static settlement reaction. The biological aggregation membrane and the sludge generated by the reaction sink to the bottom of the tank, and simultaneously, due to the existence of the aeration layer, the biological aggregation membrane falls on the upper side of the aeration layer, and the sludge can sink to the lower part of the aeration layer, and the two layers are separated. The reaction time for this step was 44 min. In the process, the water inlet gate valve of the reaction chamber 2 is opened, so that the reaction chamber 2 performs the reaction of the first step.

(III) draining and bacterium adding:

and after the second step of the reaction chamber 1 is finished, opening a water outlet gate valve and a sludge discharge gate valve of the reaction chamber 1 in sequence, so that the water body after reaction and the sludge at the bottom are discharged respectively. This process lasted 10 min. And after the water outlet and the sludge discharge are completed, opening a dosing gate valve to enable the biological aggregation film and the microbial inoculum to be fed into the reaction cavity through a bacteria feeding and dosing device, and carrying out the process for 6 min. Thereafter, all gate valves of the reaction chamber 1 are closed, so that the microbial inoculum in the reaction chamber 1 is in a propagation state, and the process is 26 min. Step three took a total of 40 min. In this process, the reaction chamber 2 performs the reaction of the second step. And the reaction cavity 3 repeats the water inlet reaction in the step one.

From FIGS. 3(a) and 3(b), it can be seen that the reactor operated well throughout the entire operating cycle, with an average nitrate removal rate of 95.04%, an average nitrite content of 0.10 mg/L in the reactor effluent, and no nitrite accumulation.

Example 6:

1. sludge enrichment domestication and biological agent preparation: a sample of the appropriate sediment was taken in a 10L Erlenmeyer flask, to which 9L of enrichment medium EM was added, and the mouth of the flask was covered with a sealing membrane to provide an anaerobic environment. Shaking the conical flask to uniformly mix the system, placing the conical flask in a constant-temperature incubator (30 ℃) for culture, taking 7 days as a culture period, slowly pouring out supernatant in the conical flask after each culture period is finished, adding a new 9L EM culture medium, shaking the conical flask for 3 times every day by using a shaking table with the rotating speed of 50 revolutions per minute, and shaking for 8 minutes every time to ensure that nutrient substances capable of allowing bacteria to grow exist in the reactor. And (3) repeatedly replacing the culture solution until the removal rate of nitrogen in the liquid culture solution measured by an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method reaches more than 80%, completing sludge enrichment, and collecting sludge.

And transferring the collected enriched sludge to a liquid DBM culture medium, carrying out constant-temperature culture, and collecting the biological agent. The preparation of the biological agent comprises the following steps: firstly, transferring enriched sludge into a liquid DBM culture medium, wherein the enriched sludge and the DBM culture medium are mixed according to the mass ratio of 1:2, carrying out constant-temperature culture at the temperature of 30 ℃, and shaking for 3 times a day and 15 minutes each time by using a shaking table with the rotating speed of 140 revolutions per minute; secondly, the DBM culture medium is replaced every 7 days, the concentration of the DBM culture medium which is replaced successively is unchanged, and the concentration of NaNO3 is increased by 50%; and completing the preparation of the biological agent until the removal rate of nitrogen in the liquid culture solution is over 75 percent by using an N- (1-naphthyl) -ethylenediamine dihydrochloride spectrophotometry method and an ultraviolet spectrophotometry method.

The formula of the Enrichment Medium (EM) is as follows: measured in terms of mass concentration (g/L), 0.48CH ₃ COONa，0.30NaHCO ₃ ，0.10NaNO ₃ ，0.08KH ₂ PO ₄ ，0.04MgCl ₂ ，0.04CaCl ₂ ，0.05PbCl ₂ 0.05 HgCl, trace element I4 mL, pH = 7.5.

The trace element solution I comprises: measured by mass concentration (g/L), 1.3EDTA, 0.22ZnSO ₄ ，0.10MnCl ₂ ·4H ₂ O，0.50MgSO ₄ ·7H ₂ O，0.30CuSO ₄ ·5H ₂ O，0.40CoCl ₂ ·6H ₂ O，0.40FeSO ₄ ·7H ₂ O，pH=7.5。

A Denitrification Basal Medium (DBM) comprising: measured in terms of mass concentration (g/L), 0.15CH ₃ COONa，0.23NaNO ₃ ，0.04KH ₂ PO ₄ ，0.04MgCl ₂ ，0.06PbCl ₂ 0.13HgCl, microelement ii 4mL, pH = 7.5.

The microelement solution II comprises: measured by mass concentration (g/L), 1.1EDTA, 0.12ZnSO ₄ ，0.08MnC ₂ ·4H ₂ O，0.60MgSO ₄ ·7H ₂ O，0.40CuSO ₄ ·5H ₂ O，0.20CoCl ₂ ·6H ₂ O，0.60 FeSO ₄ ·7H ₂ O，pH=7.5。

2. Preparing a biological aggregation membrane: mixing the DBM culture solution and the water sample of the water body to be treated according to the proportion of 4:1, placing the obtained biological agent into the mixed culture medium, placing the mixed culture medium at the constant temperature of 30 ℃ for culturing, pouring out supernatant in the culture medium every 5 days, and adding the mixed solution of the DBM culture solution and the water sample of the water body to be treated according to the proportion of 4: 1. Gradually increasing the proportion of the DBM culture solution to the water sample of the water body to be treated to 1: 6. Selecting a biological aggregation membrane with good growth and intact shape, and separating and taking out the biological aggregation membrane by adopting a filtration method.

The reactor was run as follows:

the water inlet reaction process:

after 5L of biological aggregation membrane is transferred into the reaction chamber 1, opening a water inlet gate valve, closing a water outlet gate valve and a sludge discharge gate valve, and enabling water to be treated to enter the reaction chamber 1 after passing through the grating 1, the water inlet pump 2 and the static mixer 3; so that the water intake is 74% of the reaction chamber volume. Meanwhile, the blower 10 is started to blow micro bubbles into the reaction chamber 1 from the aeration layer 11, the air inflow is controlled to be 0.06L/S, the working time of the blower 10 is 3min, the closing time is 6min, and the operation is carried out alternately in sequence. The reaction time for this step was 44 min.

(II) a static settling process:

after the reaction chamber 1 is finished, all gate valves and blowers of the reaction chamber 1 are closed, so that the reaction chamber 1 is subjected to a static settlement reaction. The biological aggregation film and the sludge generated by the reaction sink to the bottom of the tank, and simultaneously, due to the existence of the aeration layer, the biological aggregation film falls on the upper side of the aeration layer, the sludge can sink to the lower part of the aeration layer, and the two layers are separated. The reaction time for this step was 41 min. In the process, the water inlet gate valve of the reaction chamber 2 is opened, so that the reaction chamber 2 performs the reaction of the first step.

(III) draining and adding bacteria:

and after the second step of the reaction chamber 1 is finished, opening a water outlet gate valve and a sludge discharge gate valve of the reaction chamber 1 in sequence, so that the water body after reaction and the sludge at the bottom are discharged respectively. This process lasted 12 min. And after the water outlet and the sludge discharge are completed, opening a dosing gate valve to enable the biological aggregation film and the microbial inoculum to be fed into the reaction cavity through a bacteria feeding and dosing device, and carrying out the process for 5 min. Thereafter, all gate valves of the reaction chamber 1 are closed, so that the microbial inoculum in the reaction chamber 1 is in a propagation state, and the process is 25 min. Step three took a total of 45 min. In this process, the reaction chamber 2 performs the reaction of the second step. And the reaction cavity 3 repeats the water inlet reaction in the step one.

From fig. 3(a) and fig. 3(b), it can be seen that the reactor operation results were good throughout the entire operation period, the average nitrate removal rate was 96.02%, the average nitrite content of the reactor effluent was 0.09 mg/L, and no nitrite accumulation occurred.

The embodiment better illustrates the denitrification performance of the reactor, the nitrate removal rate of more than 93 percent can be realized in the school domestic sewage and sewage of sewage plants with low carbon-nitrogen ratio, and the average nitrite content of the effluent of the reactor is lower than 0.12 mg/L. And no nitrite accumulation exists, which shows that the reaction method and the reactor can realize high-efficiency denitrification in sewage with low carbon-nitrogen ratio.

The present invention is not limited to the above-mentioned embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.

Claims

1. The method for treating the sewage with the low carbon-nitrogen ratio is characterized by comprising the following steps of:

step one, preparing a biological agent:

step two, preparing the biological aggregation membrane:

step three, the reactor operates:

adding the biological aggregation membrane into the sewage, aerating, performing static settlement reaction, separating the biological aggregation membrane and sludge up and down in an aeration layer, and discharging supernatant and bottom sludge; then adding the biological agent into the residual sewage for propagation to finish the low carbon nitrogen treatment of the sewage;

the neutral enrichment medium EM comprises: CH (CH) ₃ COONa、NaHCO ₃ 、NaNO ₃ 、KH ₂ PO ₄ 、MgCl ₂ 、CaCl ₂ 、PbCl ₂ HgCl and a trace element solution I;

the neutral liquid DBM medium comprises: CH (CH) ₃ COONa、NaNO ₃ 、KH ₂ PO ₄ 、MgCl ₂ 、PdCl ₂ HgCl and a trace element solution II.

2. The method according to claim 1, characterized in that said neutral enrichment medium EM comprises, in terms of mass ratio g/L: 0.40-0.60 g/L CH ₃ COONa，0.30-0.50 g/L NaHCO ₃ ，0.10-0.20 g/L NaNO ₃ ，0.08-0.12 g/L KH ₂ PO ₄ ，0.04-0.06 g/L MgCl ₂ ，0.04-0.06 g/L CaCl ₂ ，0.04-0.06 g/L PbCl ₂ 0.04-0.06 g/L HgCl, 2-4 g/L of trace element solution I and 6.5-7.5 of pH value;

the trace element solution I comprises the following components in percentage by mass in g/L: 1.0-1.4g/LEDTA, 0.15-0.25g/LZnSO ₄ ，0.08-0.12g/LMnCl ₂ ·4H ₂ O，0.30-0.50g/LMgSO ₄ ·7H ₂ O，0.30-0.50g/LCuSO ₄ ·5H ₂ O，0.35-0.45g/LCoCl ₂ ·6H ₂ O，0.35-0.45 g/LFeSO ₄ ·7H ₂ O，pH=6.5-7.5。

3. The method according to claim 1, wherein the neutral liquid DBM culture medium comprises, in terms of mass ratio g/L: 0.15-0.25g/LCH ₃ COONa，0.15-0.25g/LNaNO ₃ ，0.04-0.06g/LKH ₂ PO ₄ ，0.04-0.06g/LMgCl ₂ ，0.08-0.12g/LPdCl ₂ 0.08-0.12g/LHgCl, 2-4 g/L of microelement solution and 6.5-7.5 of pH value;

4. The method of claim 1, wherein in the first step, the enriched sludge culture comprises: taking 6-8 days as a culture period, adding a new neutral enrichment culture medium EM after each culture period is finished, and shaking for 3-5 times per day at the rotating speed of 30-50 r/min, wherein each time lasts for 5-8 minutes;

5. The method of claim 1, wherein in the second step, the preparation of the bio-aggregation film comprises:

22) replacing the neutral liquid DBM culture medium once every 3-5 days, adding a mixed solution of the neutral liquid DBM culture medium and the water sample to be treated according to the proportion of 3:1-2.5:1, and gradually increasing the proportion of the neutral liquid DBM culture medium and the water sample to be treated to 1:5-1: 6;

6. The method of claim 1, wherein in step three, the reactor operation comprises:

7. The method as claimed in claim 6, wherein the aeration air intake is controlled to be 0.05L/S-0.08L/S, and the aeration is performed alternately for 40-45 min; the sludge is separated and deposited for 40-45min in the aeration layer at the bottom of the tank.

8. A reactor adopted according to the method of any one of claims 1 to 7, which is characterized by comprising three reaction tanks which are communicated in parallel, wherein a water inlet communicating pipeline of each reaction tank is sequentially provided with a grating (1), a water inlet pump (2), a static mixer (3) and a dosing device (4), the other pipeline of each reaction tank is provided with a bacteria dosing and dosing device (9) communicated with the static mixer (3), the bottom of each reaction tank is provided with an aeration layer (11), and the bottom of each aeration layer (11) is provided with a sludge discharge port; the side wall of the middle part of the reaction tank is provided with a water outlet.