CN111410311A - Efficient denitrification method for coupling membrane filtration and anaerobic ammonia oxidation process - Google Patents
Efficient denitrification method for coupling membrane filtration and anaerobic ammonia oxidation process Download PDFInfo
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Abstract
The invention relates to a high-efficiency denitrification method for a coupling membrane filtration and anaerobic ammonia oxidation process, which belongs to the technical field of water treatment and comprises the following steps: in the PN-ANAMMOX process, wastewater to be treated enters a nitrosation reactor to operate for one period and then stands to settle out water. And (3) enabling the effluent to enter a microfiltration membrane component with the aperture of 120-180 nm, enabling nitrosation effluent to enter from one side of the membrane and penetrate out from the other side of the membrane through pressure difference, removing suspended matters and heterotrophic bacteria in the anaerobic ammonia oxidation influent, and improving the quality of the influent. And then, removing 30-50% of COD concentration in the nitrosation effluent through activated carbon, and then performing anaerobic ammonia oxidation reaction operation, so that the anaerobic ammonia oxidation stably operates and high-efficiency nitrogen removal load is kept. The stable anaerobic ammonia oxidation process operation is formed, the influence of water inlet suspended matters or heterotrophic bacteria on the anaerobic ammonia oxidation operation is reduced, and the method is an efficient, energy-saving and stable wastewater denitrification treatment method.
Description
Technical Field
The invention belongs to the technical field of water treatment.
Background
In recent years, anammox processes have been used as a new and promising method of wastewater treatment to treat wastewater having a higher ammonium concentration and a lower COD content. In the traditional biological denitrification process, two processes of nitrification and denitrification are included, and in an aerobic environment, nitrifying bacteria take inorganic carbon as a carbon source and oxygen as an electron acceptor to oxidize ammonia nitrogen in wastewater into nitrate nitrogen; in an anaerobic/anoxic environment, denitrifying bacteria reduce nitrate nitrogen to nitrogen gas by using organic carbon as a carbon source and an electron donor. With the development of biological denitrification technology, novel denitrification processes such as short-cut denitrification, aerobic denitrification, synchronous nitrification-denitrification, PN-ANAMMOX and the like are developed, and the application of the novel denitrification processes solves the problem that wastewater with low C/N ratio and high ammonia nitrogen content is difficult to treat. In the PN-ANAMMOX process, wastewater firstly enters an anaerobic ammonia oxidation process after undergoing a nitrosation reaction, although a period of standing precipitation is carried out, a small amount of suspended matters and heterotrophic bacteria enter the anaerobic ammonia oxidation process along with water inflow, and in view of the characteristics of slow growth and long growth period of the anaerobic ammonia oxidation bacteria, the heterotrophic bacteria taking organic carbon as a raw material and the anaerobic ammonia oxidation bacteria generate survival competition in a reactor and have adverse effects on the anaerobic ammonia oxidation bacteria. Therefore, the membrane filtration system is introduced to be applied to the front end of the anaerobic ammonia oxidation process to intercept suspended matters and heterotrophic bacteria (even large-particle organic matters) in the inlet water of the anaerobic ammonia oxidation process.
The common membrane technology applications in the existing anammox process are generally divided into the following three concepts:
firstly, as the application of the membrane bioreactor MBR intercepted at the rear end, the good retention performance of the membrane bioreactor is utilized to intercept and fix the bacteria in the operation process, and the water quality of the effluent is optimized while the bacteria are fixed. The method is commonly used in experiments for enriching and culturing obligate anammox bacteria, and experiments prove that the anammox bacteria are dominant bacteria in an MBR (membrane bioreactor).
The other is the application of membrane aeration as a carrier in a reactor. In the research process, the concentration of dissolved oxygen in water is required to be controlled, membrane aeration can control the dissolved oxygen, the diffusion efficiency is higher than that of the common aeration technology, and meanwhile volatile organic compounds and greenhouse gases in the gas are reduced, so that the aeration quality is improved. Meanwhile, in the membrane aeration system, a large surface area is provided for the bacteria, and the bacteria are allowed to grow on the surface in an enrichment way.
Third, pre-filtration was performed at the front of the reaction, and experiments were from Imperial college in London, Stuckey, with a slight modification of the concept of nitrifying biofilms growing on the membrane surface, i.e. ammonium diffusion through the tube side. Nitrifying bacteria grow on the shell side of the membrane module by continuously circulating a cell suspension through the shell side. This allows nitrite control, culture independent of wastewater flow, and allows concentrated culture to develop on the shell side of the membrane module. This increases the efficiency of ammonium conversion and reduces the cost of aeration and reactor operation compared to prior art treatment techniques.
Disclosure of Invention
The invention aims to reduce partial adverse effects on an anaerobic ammonia oxidation process in the existing PN-ANAMMOX process, provide an optimization method for maintaining stable growth of anaerobic ammonia oxidation bacteria, reduce heterotrophic bacteria, suspended matters and the like in inlet water from entering the anaerobic ammonia oxidation process, and compete with the anaerobic ammonia oxidation bacteria under the promotion of an actual organic carbon source of wastewater. Meanwhile, the organic carbon concentration in the water is reduced, and the partial inhibition effect of the organic carbon concentration in the water on the anaerobic ammonium oxidation bacteria is reduced.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
a high-efficiency denitrification method for a coupled membrane filtration and anaerobic ammonia oxidation process is characterized by comprising the following steps: in the PN-ANAMMOX process, wastewater to be treated enters a nitrosation reactor to operate for one period and then stands to settle out water. And enabling the effluent to enter a membrane system assembly with the aperture of 120-180 nm, enabling nitrosation effluent to enter from one side of the membrane and penetrate out from the other side of the membrane through pressure difference, removing suspended matters and heterotrophic bacteria in the anaerobic ammonia oxidation influent, and improving the quality of the influent.Subsequently, the process of the present invention,removing 30-50% of COD concentration in the nitrosation effluent by using activated carbon, and then performing anaerobic ammonia oxidation reaction operation, so that the anaerobic ammonia oxidation stably operates and high-efficiency nitrogen removal load is maintained. The method forms a stable anaerobic ammonia oxidation process operation, reduces the influence of inflow suspended matters or heterotrophic bacteria on the anaerobic ammonia oxidation operation, and is a high-efficiency, energy-saving and stable wastewater denitrification treatment method.
The membrane system assembly is arranged at the front end of the anaerobic ammonia oxidation process and is used for filtering the anaerobic ammonia oxidation inlet water. The membrane module is applied to the middle position of partial nitrosation and anaerobic ammonia oxidation in the existing PN-ANAMMOX process. Then adding part of active carbon to remove part of the active carbon concentration.
The membrane system component adopts a microfiltration membrane system, and the membrane aperture is 120-180 nm; the bottom layer is non-woven fabric, and a PVDF active layer is covered on the non-woven fabric through a phase inversion method; the contact angle is between 75 and 80. Can effectively remove suspended matters, heterotrophic bacteria and the like in water, has the removal rate of over 90 percent, and has good effect on improving the quality of the anammox influent water.
In the anaerobic ammonia oxidation reaction, 10-30 g of activated carbon is added into every 200ml of actual wastewater, so that the removal rate of organic carbon reaches 30-50%, and the inhibition of high-concentration activated carbon on the operation of an anaerobic ammonia oxidation process is reduced.
The method has the application range including but not limited to thermal hydrolysis sludge digestion liquid, high nitrogen content and high organic matter content industrial wastewater and the like, and is suitable for industrial sewage with high nitrogen concentration, high COD concentration and complex components.
The PN-ANAMMOX process can be operated by adopting an SPR process in the whole process, and nitrosation effluent passes through the membrane module after settling and standing, so that pollution of SS in water to the membrane module can be reduced, membrane flux is improved, and service life of the membrane module is prolonged.
Compared with the prior art, the invention has the following characteristics and beneficial effects:
1. the microfiltration membrane component is used at the front end of the anaerobic ammonia oxidation process to filter suspended matters and heterotrophic bacteria, so that the suspended matters and heterotrophic bacteria which may influence the anaerobic ammonia oxidation bacteria are removed. Compared with the anaerobic ammonia oxidation process which is generally carried out by UN and is not subjected to membrane filtration, the method reduces the heterogeneous bacteria which possibly compete with the anaerobic ammonia oxidation bacteria in the inlet water, so as to improve the stable growth of the anaerobic ammonia oxidation bacteria and maintain the stable operation of the anaerobic ammonia oxidation process for biological nitrogen removal.
2. The activated carbon is used for removing part of COD concentration in the wastewater, and in the anaerobic ammonia oxidation process for treating high COD concentration, the COD concentration is removed through the activated carbon, so that the water quality is improved, and the adverse effect on the anaerobic ammonia oxidation bacteria is less than that of the wastewater without the COD content removed through the activated carbon.
3. Compared with the traditional nitrification-denitrification process, the anaerobic ammonia oxidation process has the advantages that the organic carbon source is reduced by 100 percent, the oxygen demand is reduced by 60 percent，The production of excess sludge is reduced by 90%.
Drawings
FIG. 1 is a process flow diagram of a high efficiency denitrification process and method of the present invention coupled with membrane filtration and anammox process;
Detailed Description
The high-efficiency denitrification method for the coupled membrane filtration and anaerobic ammonia oxidation process specifically comprises the following steps (as shown in figure 1):
the first step is that sewage enters a nitrosation reaction tank, and ammonia nitrogen in nitrosation effluent is enabled to be: the ratio of nitrite nitrogen is close to 1:1.32, meeting the requirements of subsequent reaction, and standing to precipitate out water. Flows into the membrane module.
And a second step, enabling the effluent to enter a microfiltration membrane component with the aperture of 120-180 nm, enabling nitrosation effluent to enter from one side of the membrane and penetrate out from the other side of the membrane through pressure difference, removing suspended matters and heterotrophic bacteria in the anaerobic ammonia oxidation influent, and improving the quality of the influent.
And the third step, adding 10-30 g of activated carbon into every 200m of L nitrosation effluent to ensure that the removal rate of COD reaches 30-50%.
And step four, after removing part of COD concentration in the water, the anaerobic ammonia oxidation reactor is operated in a rear-end anaerobic ammonia oxidation process to ensure that the anaerobic ammonia oxidation reactor is stably operated, and the removal load of medium and high total nitrogen is maintained.
The first step is that the sewage enters a nitrosation stage to operate, the influence of the water quality and other reasons on the nitrosation operation in the nitrosation stage can be adjusted and improved through optimized operation, the concentration ratio of ammonia nitrogen to nitrite nitrogen in the wastewater is maintained to be close to 1:1.32, and the subsequent reaction operation is met.
And in the second step, the water after nitrosation treatment enters a membrane system after standing and settling, and the membrane component is made of a non-woven fabric material and has a pore size of 120-180 nm, so that the effect of removing heterotrophic bacteria of suspended matters in the water is good.
And in the third step, activated carbon with proper dosage is added into the nitrosation effluent after membrane filtration, and the COD concentration in the water is reduced through physical adsorption. The adverse effect of COD on the anaerobic ammonia oxidation operation process is reduced.
And the fourth step is that the effluent after the nitrosation reaction through membrane filtration enters an anaerobic ammonia oxidation process, and suspended matters and heterotrophic bacteria in the effluent are removed, so that the suspended matters which possibly have adverse effects on bacteria derivation in the anaerobic ammonia oxidation influent are reduced.
The following further illustrates an embodiment of the present invention with reference to fig. 1.
Example (b):
the ammonia nitrogen concentration of the thermal hydrolysis sludge digestion biogas slurry is 1500-2000 mg/L concentration is 2000-2500 mg/L, the ammonia nitrogen concentration of the biogas slurry entering the nitrosation process operation outlet water is 400-700 mg/L, the nitrite nitrogen concentration of the outlet water is 400-700 mg/L, the COD concentration of the outlet water is 1200-1700 mg/L, the nitrosation outlet water directly enters the oxygen ammoxidation process, the ammonia nitrogen concentration of the outlet water after the anaerobic ammonia oxidation process operation is 100-150 mg/L, the nitrite nitrogen concentration of the outlet water is 0-10 mg/L, and the anaerobic ammonia oxidation operation load is 0.4kgN/m 3/d.
In the two-stage PN-ANAMMOX process, a membrane module is added to remove suspended matters and heterotrophic bacteria, and a proper amount of activated carbon is added into nitrosation effluent filtered by the membrane module. The removal rate of the membrane module to suspended matters and heterotrophic bacteria is as high as 92-97%. The COD concentration removed by the activated carbon reaches 30-50%. When the nitrosation effluent subjected to membrane filtration and activated carbon adsorption enters the anaerobic ammonia oxidation process to operate, the anaerobic ammonia oxidation process can operate more stably, and the nitrogen removal load is increased by 10-30%.
Claims (2)
1. A high-efficiency denitrification method for a coupled membrane filtration and anaerobic ammonia oxidation process is characterized by comprising the following steps: in the PN-ANAMMOX process, the wastewater to be treated enters a nitrosation reactor to be treatedStanding and settling the effluent after the periodic operation. And enabling the effluent to enter a membrane system assembly with the aperture of 120-180 nm, enabling nitrosation effluent to enter from one side of the membrane and penetrate out from the other side of the membrane through pressure difference, removing suspended matters and heterotrophic bacteria in the anaerobic ammonia oxidation influent, and improving the quality of the influent.Subsequently, the process of the present invention,removing 30-50% of COD concentration in the nitrosation effluent by using activated carbon, and then performing anaerobic ammonia oxidation reaction operation, so that the anaerobic ammonia oxidation stably operates and high-efficiency nitrogen removal load is maintained. The method forms a stable anaerobic ammonia oxidation process operation, reduces the influence of inflow suspended matters or heterotrophic bacteria on the anaerobic ammonia oxidation operation, and is a high-efficiency, energy-saving and stable wastewater denitrification treatment method.
2. The method for high efficiency denitrification with coupled membrane filtration and anammox process of claim wherein the steps are performed by:
the first step is that sewage enters a nitrosation reaction tank, and ammonia nitrogen in nitrosation effluent is enabled to be: the ratio of nitrite nitrogen is close to 1:1.32, meeting the requirements of subsequent reaction, standing to precipitate water, and allowing the water to flow into a membrane module;
the second step, the effluent enters a microfiltration membrane component with the aperture of 120-180 nm, nitrosation effluent enters from one side of the membrane through pressure difference, and penetrates out from the other side of the membrane, so that suspended matters and heterotrophic bacteria in the anaerobic ammonia oxidation influent are removed, and the quality of the influent is improved;
step three, adding 10-30 g of activated carbon into every 200m of L nitrosation effluent to ensure that the removal rate of COD reaches 30-50%;
and step four, after removing part of COD concentration in the water, the anaerobic ammonia oxidation reactor is operated in a rear-end anaerobic ammonia oxidation process to ensure that the anaerobic ammonia oxidation reactor is stably operated, and the removal load of medium and high total nitrogen is maintained.
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| CN113003858A (en) * | 2021-02-09 | 2021-06-22 | 兰州理工大学 | Short-cut nitrification coupling anaerobic ammonia oxidation denitrification treatment device |
| CN115231770A (en) * | 2022-07-06 | 2022-10-25 | 中国矿业大学(北京) | System and method for treating coal chemical industry wastewater by coupling anaerobic ammonia oxidation of ceramic membrane bioreactor |
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| CN115231770B (en) * | 2022-07-06 | 2023-10-24 | 中国矿业大学(北京) | System and method for treating coal chemical wastewater by coupling ceramic membrane bioreactor with anaerobic ammonia oxidation |
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