Biofilm reactor biofilm culturing method with nitrogen and phosphorus removal function
Technical Field
The invention belongs to the technical field of wastewater treatment, and particularly relates to a biofilm reactor biofilm culturing method with nitrogen and phosphorus removal functions.
Background
The biofilm method refers to that microorganisms in sewage treatment are attached or fixed on the surface of a biological filler to form a layer of biofilm, and the microorganisms in the biofilm are used for degrading organic matters, nitrogen-containing pollutants and other harmful components. The biofilm method has the advantages of stable operation, less excess sludge, simple management, strong removal capability on ammonia nitrogen and refractory pollutants, capability of adapting to larger water quality range change and the like, and is widely applied to the treatment of domestic sewage and industrial wastewater. According to different operation modes, the biological filter can be divided into a biological filter, a biological rotating disc, a biological contact oxidation method, a biological fluidized bed and the like. Although the biofilm method has higher treatment efficiency, the method has obvious effect on organic matters and water bodies containing nitrogen pollutants. However, the biofilm method has the defects of long biofilm formation time, easy falling of the biofilm, low biomass, unstable removal efficiency of nitrogen-containing pollutants and the like. Especially for the deep nitrogen and phosphorus removal of oily sewage of refining and chemical enterprises, the conditions of difficult biofilm formation and long start-up period generally exist, and the ideal deep nitrogen and phosphorus removal effect cannot be achieved.
CN 200710061583.9 discloses a biofilm culturing method for filler in a biological contact oxidation pond, which increases the amount of microorganisms on the filler by sludge circulation, aeration and suspended microorganism discharge, and cultures a biofilm by controlling organic load. The method is suitable for the suspended filler aerobic biofilm formation process. CN105565480A discloses a biofilm formation method of carrier filler in a moving bed biofilm reactor, which comprises the steps of simultaneously draining water and supplementing ion exchange wastewater to the moving bed biofilm reactor, carrying out dynamic culture, and refluxing activated sludge. CN106542655A discloses a method for quickly biofilm formation of a high-efficiency denitrification microbial agent, which adopts an aerobic nitrification reactor to biofilm formation, can overcome the defects of long time for biofilm formation of denitrification microorganisms, poor adhesion, complex operation, low biomass and poor impact load resistance, improves the fixation amount of nitrobacteria, has high biofilm formation speed, and can enhance the capability of resisting the change of the external environment and the capability of resisting the impact load. But the removal rate of the ammonia nitrogen of the biological film is more than or equal to 95 percent, and the method is suitable for treating sewage containing ammonia nitrogen pollutants. CN201811572943.6 discloses a method for fast biofilm formation of a biofilm reactor, which comprises the following steps: (1) inoculating aerobic activated sludge in a reactor loaded with biological fillers, performing biofilm culturing by using industrial sewage under aerobic conditions, and adding an organic carbon source and humus in the culturing process; (2) when the concentration of the sludge in the effluent is basically stable and unchanged, inoculating anaerobic activated sludge in the reactor, transferring to anaerobic conditions for biofilm culturing, and adding sugar alcohol compounds and humus in the culturing process. The method can enable anaerobic bacteria to quickly add value in the reactor, has high biofilm formation speed and short start period, prevents the biofilm from easily falling off, and ensures that the biofilm reactor stably achieves the deep denitrification effect. But does not relate to the proliferation and biofilm formation of aerobic bacteria, and the application of the aerobic bacteria in the treatment of sewage containing ammonia nitrogen and phosphorus pollutants is limited.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a biofilm reactor biofilm culturing method with the functions of nitrogen and phosphorus removal. The method of the invention can ensure that the growth condition of microorganisms on the filler is good, the rapid biofilm formation growth of nitrobacteria and denitrifying phosphorus bacteria is realized, the starting period is short, the biofilm is not easy to fall off, and the biofilm reactor is ensured to stably achieve the effects of deep nitrogen and phosphorus removal.
The invention provides a biofilm reactor biofilm culturing method with nitrogen and phosphorus removal functions, which comprises the following steps:
inoculating activated sludge with nitrogen and phosphorus removal functions in a biofilm reactor loaded with biological fillers, introducing industrial sewage into the reactor, and performing biofilm culturing in an anaerobic and aerobic alternate mode, wherein free amino acid is added in the aerobic reaction process, sugar ester substances are added in the anaerobic reaction process, and quaternary ammonium base is added when dissolved oxygen is reduced to be below 0.1 mg/L.
In the method, the requirements for controlling the end of the biofilm culturing of the reactor are as follows: the total nitrogen concentration of effluent is lower than 15mg/L, the total phosphorus concentration is lower than 0.5mg/L, and the operation is continuously and stably carried out for at least 7 days.
In the method, the activated sludge with the nitrogen and phosphorus removal functions is taken from the activated sludge in the secondary sedimentation tank of the sewage treatment plant and is inoculated according to the sludge concentration of 3000-4000 mg/L. The activated sludge with the nitrogen and phosphorus removal function contains microorganisms for removing COD, ammonia nitrogen, total nitrogen and the like, and also contains phosphorus-accumulating microorganisms.
In the method, the ammonia nitrogen concentration in the industrial sewage is 5-50mg/L, the total nitrogen concentration is 50-100mg/L, the COD is 100-500mg/L (Cr method, the same below), and the total phosphorus concentration is 5-15 mg/L.
In the method of the invention, the aerobic culture conditions are as follows: the concentration of dissolved oxygen is 0.5-4.5mg/L, the pH is 7-8, and the temperature is 25-35 ℃; the anaerobic conditions are as follows: the dissolved oxygen concentration is 0-1.0mg/L, the temperature is 28-35 ℃, and the pH is 7.5-8.5.
The method can adopt an intermittent water inlet operation mode, a continuous water inlet operation mode, or an operation mode of firstly intermittently feeding water and then continuously feeding water.
In the method, when an operation mode of firstly intermittently feeding water and then continuously feeding water is adopted, the operation mode of intermittently feeding water is firstly adopted, and the operation mode of intermittently feeding water is converted into the operation mode of continuously feeding water until the Total Nitrogen (TN) removal rate is more than 70 percent.
In the method, when an intermittent water inlet operation mode is adopted, the reaction time of each batch is 6-12h, free amino acid is added under the first aerobic condition during water inlet, sugar ester substances are added under the first anaerobic condition, and quaternary ammonium base is added when the dissolved oxygen is reduced to be below 0.1 mg/L; the aerobic and anaerobic processes are alternated for 2-5 times (namely 2-5 times of aerobic and anaerobic processes) in each batch of water inlet, and the ratio of the aerobic to anaerobic reaction time is 1:1-5: 1.
In the method, when a continuous water inlet operation mode is adopted, the hydraulic retention time is controlled to be 6-12 h. Aerobic and anaerobic conditions are regulated through the concentration of ammonia nitrogen and total nitrogen, when the concentration of the ammonia nitrogen in effluent cultured under the aerobic condition is lower than 15mg/L, the effluent enters an anaerobic condition culture stage, and when the concentration of the total nitrogen is lower than 25mg/L, the effluent enters an aerobic condition culture stage. Wherein, free amino acid is added under the first aerobic condition when water is fed into each batch, sugar ester substances are added under the first anaerobic condition, and quaternary ammonium hydroxide is added when the dissolved oxygen is reduced to be below 0.1 mg/L.
In the method of the present invention, the free amino acid includes at least one of proline, hydroxyproline, glycine, arginine, and the like, and proline is preferred. The amount of the free amino acid is 0.001-1.0mg/L, preferably 0.01-0.10 mg/L.
In the method of the present invention, the sugar ester substance comprises at least one of rhamnose ester, trehalose glycolipid, sophorolipid and sucrose ester, and the like, preferably rhamnose ester. The quaternary ammonium base is at least one of phosphorylcholine, betaine, tetramethylammonium hydroxide and the like, and the phosphorylcholine is preferred. The dosage of the sugar ester substances is 0.001-1.0mg/L, preferably 0.01-0.10 mg/L. The dosage of the quaternary ammonium base is 0.001-1.0mg/L, preferably 0.01-0.10 mg/L.
In the method of the invention, the biofilm reactor can be a biological aerated filter, a biological fluidized bed, a moving bed reactor and the like.
In the method of the present invention, the biological filler includes, but is not limited to, a suspension filler, a soft filler, a combined filler, a braid filler or a carbon fiber filler.
Compared with the prior art, the invention has the following beneficial effects:
(1) the method of the invention adopts aerobic and anaerobic conditions to alternately carry out biofilm reactor biofilm formation, can cause part of microorganisms to secrete extracellular polymers due to the change of environmental conditions, provides attachment growth conditions for the growth and the propagation of the organisms, can shorten the biofilm formation time, can promote the cooperative growth of multiple floras of nitrobacteria, aerobic phosphorus accumulating bacteria and denitrifying phosphorus accumulating bacteria, and finally realizes the common removal of COD, total nitrogen and total phosphorus in the sewage.
(2) The method can improve the effective transfer of oxygen and the full utilization of multiple matrixes under aerobic conditions by adding free amino acid, is favorable for the competition of autotrophic nitrifying bacteria and heterotrophic nitrifying bacteria on substrates, further stimulates the enzyme activity to increase the number of nitrifying bacteria and improve the nitrification capability, and can reduce the competition of phosphorus accumulating bacteria and nitrifying bacteria on dissolved oxygen and improve the aerobic phosphorus uptake capability of the phosphorus accumulating bacteria. Under the anaerobic condition, the activity of nitrate reductase can be improved, the utilization of nitrate as an electron acceptor by denitrifying bacteria is enhanced, and the growth and the propagation of denitrifying phosphorus accumulating bacteria are promoted by adding sugar ester substances and then adding quaternary ammonium base in a matching manner. By the method, the multi-flora cooperative rapid growth of the nitrifying bacteria, the aerobic phosphorus accumulating bacteria and the denitrifying phosphorus accumulating bacteria can be realized, and the film forming effect is improved.
Detailed Description
The technical solution of the present invention will be described in further detail with reference to examples. The embodiments are implemented on the premise of the technical scheme of the invention, and detailed implementation modes and specific operation processes are given, but the protection scope of the invention is not limited by the following embodiments.
The experimental procedures in the following examples are, unless otherwise specified, conventional in the art. The test materials used in the following examples were purchased from biochemical reagent stores unless otherwise specified.
In the method, the COD concentration is determined by GB11914-89 bichromate method which is the determination of chemical oxygen demand of water quality; the ammonia nitrogen concentration is measured by GB7478-87 (determination of ammonium water quality-distillation and titration method), the total nitrogen concentration is measured by GB 11894-89 (determination of water quality-total nitrogen-alkaline potassium persulfate digestion ultraviolet spectrophotometry), and the total phosphorus concentration is measured by GB11893-89 (ammonium molybdate spectrophotometry). The relative abundance at the level of nitrifying bacteria and denitrifying polyphosphates can be determined analytically using a high throughput sequencer.
Example 1
Sponge filler is loaded in a 100L reactor (biological aerated filter), activated sludge of a secondary sedimentation tank of a sewage treatment plant is inoculated according to the sludge concentration of 3000mg/L, and the activated sludge contains microorganisms for removing COD, ammonia nitrogen, total nitrogen and the like and also contains phosphorus-accumulating microorganisms. Certain industrial sewage is fed from the upper part of a reactor for biofilm culturing, the ammonia nitrogen concentration in the sewage is 30mg/L, the total nitrogen concentration is 100mg/L, the COD is 400mg/L, and the total phosphorus concentration is 12 mg/L. An intermittent water inlet operation mode is adopted, water is fed for 1 hour in each batch, water is discharged for 1 hour after the reaction is carried out for 6 hours, continuous water feeding is carried out when the TN removal rate is more than 70%, and the hydraulic retention time is 6 hours.
Anaerobic conditions and aerobic conditions are alternately carried out in the culture process, when an intermittent water feeding operation mode is adopted, water feeding in each batch is carried out for 2 times of aerobic and anaerobic alternation, the ratio of aerobic to anaerobic reaction time is 2:1, when a continuous water feeding operation mode is adopted, an anaerobic condition culture stage is carried out when the concentration of ammonia nitrogen in effluent is lower than 15mg/L during aerobic condition culture, and an aerobic condition culture stage is carried out when the concentration of total nitrogen is lower than 25 mg/L. Wherein the aerobic culture conditions are as follows: the dissolved oxygen concentration was 1.0mg/L, the pH was 7.2, and the temperature was 30 ℃. Proline was added to the treated wastewater at a concentration of 0.01mg/L during the first aerobic reaction of each batch of influent water. The anaerobic conditions are as follows: the dissolved oxygen concentration is below 0.2mg/L, the temperature is 30 ℃, and the pH is 7.5. In the first anaerobic reaction process of each batch of water inlet, rhamnose ester is added according to the concentration of 0.01mg/L added into the treated wastewater, and 0.01mg/L of phosphorylcholine is added when the dissolved oxygen is reduced to be below 0.1 mg/L.
After 16 days of biofilm culturing, the total nitrogen concentration of the effluent is continuously analyzed for 7 days, the total nitrogen concentration of the effluent is lower than 15mg/L, the average total nitrogen concentration is 13.8mg/L, the total phosphorus concentration is lower than 0.5mg/L, and the average total phosphorus concentration is 0.35mg/L, and the biofilm culturing of the reactor is successfully completed. The reactor after film formation is used for continuously treating the wastewater, the average concentration of the total nitrogen of the effluent is 10mg/L and the average concentration of the total phosphorus is 0.39mg/L after the operation for 3 months.
Example 2
This example is compared to example 1 with the following differences: glycine is added into the wastewater with the concentration of 0.01mg/L in the first aerobic reaction process; during the first anaerobic reaction, trehalose ester is added according to the concentration of 0.01mg/L added into the treated wastewater, and when the dissolved oxygen is reduced to below 0.1mg/L, 0.01mg/L betaine is added.
And (4) after the biofilm culturing is carried out for 17 days, analyzing the total nitrogen concentration of the effluent continuously for 7 days, wherein the total nitrogen concentration of the effluent is lower than 15mg/L, the average total nitrogen concentration is 14.4mg/L, the total phosphorus concentration is lower than 0.5mg/L, and the average total phosphorus concentration is 0.45mg/L, and successfully completing the biofilm culturing of the reactor. The reactor after film formation is used for continuously treating the wastewater, the average concentration of the total nitrogen of the effluent is 12mg/L and the average concentration of the total phosphorus is 0.44mg/L after the operation for 3 months.
Example 3
This example is compared to example 1 with the following differences: proline is added into the treated wastewater according to the concentration of 0.1mg/L in the first aerobic reaction process, rhamnose ester is added into the treated wastewater according to the concentration of 0.1mg/L in the first anaerobic reaction process, and 0.01mg/L of choline phosphate is added when the dissolved oxygen is reduced to be below 0.1 mg/L.
After 16 days of biofilm culturing, the total nitrogen concentration of the effluent is continuously analyzed for 7 days, the total nitrogen concentration of the effluent is lower than 15mg/L, the average total nitrogen concentration is 13.6mg/L, the total phosphorus concentration is lower than 0.5mg/L, and the average total phosphorus concentration is 0.33mg/L, and the biofilm culturing of the reactor is successfully completed. The reactor after film formation is used for continuously treating the wastewater, the average concentration of the effluent total nitrogen is 9mg/L and the average concentration of the total phosphorus is 0.36mg/L after the reactor is operated for 3 months.
Example 4
This example is compared to example 1 with the following differences: the ammonia nitrogen concentration of the wastewater for biofilm formation is 10mg/L, the total nitrogen concentration is 50mg/L, the COD is 100mg/L, and the total phosphorus concentration is 8 mg/L.
After 16 days of biofilm culturing, the total nitrogen concentration of the effluent is continuously analyzed for 7 days, the total nitrogen concentration of the effluent is lower than 15mg/L, the average total nitrogen concentration is 14.6mg/L, the total phosphorus concentration is lower than 0.5mg/L, and the average total phosphorus concentration is 0.47mg/L, and the biofilm culturing of the reactor is successfully completed. The reactor after film formation is used for continuously treating the wastewater, the average concentration of the total nitrogen of the effluent is 12mg/L and the average concentration of the total phosphorus is 0.46mg/L after the operation for 3 months.
Comparative example 1
This comparative example is different from example 1 in that: proline is not added in the aerobic reaction process.
After 30 days, the membrane-hanging culture of the reactor is successfully completed, the total nitrogen concentration of effluent is lower than 15mg/L and the total phosphorus concentration is lower than 0.5mg/L after 7 days. The reactor after film formation is used for continuously treating the wastewater, the total nitrogen concentration of effluent begins to rise after 1 month of operation, the total nitrogen removal rate is lower than 85 percent, the total phosphorus removal rate is lower than 90 percent, and the ammonia nitrogen concentration is as high as 12 mg/L.
Comparative example 2
This comparative example is different from example 1 in that: rhamnose ester and phosphorylcholine are not added in the anaerobic reaction process.
After 32 days, the membrane-hanging culture of the reactor is successfully completed, the total nitrogen concentration of effluent is lower than 15mg/L and the total phosphorus concentration is lower than 0.5mg/L after 7 days. The reactor after film formation is used for continuously treating the wastewater, the total nitrogen concentration of effluent begins to rise after 1 month of operation, the total nitrogen removal rate is lower than 85 percent, the total phosphorus removal rate is lower than 85 percent, and the ammonia nitrogen concentration is as high as 10 mg/L.
Comparative example 3
This comparative example is different from example 1 in that: the film forming process only adopts aerobic conditions.
After the biofilm culturing for 16 days, the total nitrogen concentration of effluent is still as high as 45mg/L, and the total phosphorus concentration is as high as 7.9mg/L, and the biofilm culturing of the reactor is not finished.
Comparative example 4
This comparative example is different from example 1 in that: the film forming process only adopts anaerobic conditions.
After the biofilm culturing is carried out for 16 days, the ammonia nitrogen concentration of effluent is still as high as 20mg/L, the total nitrogen concentration is still as high as 39mg/L, and the total phosphorus concentration is as high as 8.8mg/L, so that the biofilm culturing of the reactor is not finished.
Comparative example 5
This comparative example is different from example 1 in that: adding rhamnose ester and phosphorylcholine under aerobic condition, and adding proline under anaerobic condition.
After the biofilm culturing is carried out for 16 days, the ammonia nitrogen concentration of effluent is still as high as 18mg/L, the total nitrogen concentration is still as high as 34mg/L, and the total phosphorus concentration is as high as 6.7mg/L, so that the biofilm culturing of the reactor is not finished.