WO2021128308A1

WO2021128308A1 - Sewage treatment system and method for strengthening anaerobic ammonia oxidation denitrification and dephosphorization of domestic sewage

Info

Publication number: WO2021128308A1
Application number: PCT/CN2019/129340
Authority: WO
Inventors: 戴玉女; 杨扬; 熊春晖; 张晓萌; 唐小燕
Original assignee: 暨南大学
Priority date: 2019-12-26
Filing date: 2019-12-27
Publication date: 2021-07-01
Also published as: CN110921833B; CN110921833A

Abstract

Disclosed is a sewage treatment system for strengthening anaerobic ammonia oxidation denitrification and dephosphorization of domestic sewage, the system comprising a filtering module, an anaerobic-aerobic-anoxic baffled reactor AOABR module, a water distribution module and a combined constructed wetland module, which are connected in succession. By arranging the AOABR module at the front end of the combined constructed wetland module, an organic load entering the constructed wetland can be reduced, the risk of the wetland becoming blocked is reduced, the abundance of anaerobic ammonia oxidation autotrophic bacteria in a first-stage saturated flow wetland is increased, an ammonia nitrogen substrate required for an anaerobic ammonia oxidation reaction is retained and micro-aerobic conditions are created on on the surface layer of the wetland to form a nitrite nitrogen substrate. Under the condition of a low-organic-matter load, the mutual benefit and symbiosis of denitrifying and dephosphorizing bacteria and anaerobic ammonium oxidation bacteria in a saturated flow wetland are also facilitated, the coupled synergistic removal of nitrogen and phosphorus is realized under the conditions of low energy consumption and carbon limitation, and by combining multi-stage saturated and unsaturated flow wetlands, the total nitrogen removal efficiency and the total phosphorus removal efficiency can be up to 90% or above.

Description

Sewage treatment system and method for strengthening anaerobic ammonia oxidation denitrification and simultaneous dephosphorization of domestic sewage

Technical field

The present invention relates to the technical field of water treatment, in particular to a sewage treatment system and method for enhancing anaerobic ammonia oxidation and denitrification and simultaneous dephosphorization of domestic sewage.

Background technique

Constructed wetland is an economical, environmentally friendly and eco-friendly water treatment technology, which mainly includes three types: vertical flow constructed wetland, horizontal subsurface flow constructed wetland and surface flow constructed wetland. It treats sewage through the synergy of substrates, plants and microorganisms, which can not only effectively purify water quality, but also provide habitats for wild animals. In addition, compared with traditional sewage treatment systems, constructed wetlands are simple in structure, easy to maintain, and low in operating costs, so they are widely used in the treatment of multiple types of sewage.

At present, people generally use the different aerobic and anaerobic environments in the combined constructed wetland to improve the denitrification effect through nitrification and denitrification. However, the constructed wetland has the disadvantage of easy clogging. In order to solve this problem, aerobic is usually added at the front end of the constructed wetland. Or anaerobic biological treatment system, which greatly reduces the content of organic matter entering the constructed wetland, thereby reducing the risk of clogging of the constructed wetland. However, the reduction of organic carbon sources has led to great restrictions on the subsequent denitrification and denitrification of constructed wetlands. People usually choose the addition of exogenous organic carbon sources to improve the denitrification effect, but it will inevitably increase the operation and maintenance costs of constructed wetlands.

In addition, the removal of phosphorus in constructed wetlands is more difficult, which mainly relies on substrate adsorption, followed by the absorption and assimilation of plants and some microorganisms. However, after long-term operation of the constructed wetland substrate, adsorption saturation will occur. In this regard, people usually take some measures (such as replacing fillers) to restore the phosphorus removal performance of the constructed wetland, but this will destroy the original ecosystem structure of the constructed wetland and increase the operating cost of the constructed wetland.

Therefore, in view of the existing problems, it is necessary to develop a new type of denitrification sewage treatment system that does not rely on the restriction of organic carbon sources, while solving the problems of easy clogging of constructed wetlands and unstable phosphorus removal efficiency.

Summary of the invention

The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a sewage treatment system that enhances the anaerobic amination and denitrification of domestic sewage while simultaneously dephosphorizing. The present invention can significantly improve the effect of denitrification and phosphorus removal and effectively prevent wetland clogging. , Increase the service life of wetlands.

Another object of the present invention is to provide a method for treating sewage using the above sewage treatment system.

In order to achieve the above objectives, the present invention is achieved through the following solutions:

A sewage treatment system that strengthens the anaerobic ammonia oxidation denitrification and dephosphorization of domestic sewage, including successively connected filter modules, Anaerobic-Aerobic-Anoxic Baffled Reactor (AOABRR) ) Module, water distribution module and combined constructed wetland module; the filter module is connected to the AOABR module through a submersible pump, and the water distribution module is connected to the combined constructed wetland module through a lift pump; the filter module is provided with a water inlet, and the combined constructed wetland module is provided The water outlet; the filter module is a grid sedimentation tank; the AOABR module includes an anaerobic tank, an aerobic tank and an anoxic tank connected in sequence; the water distribution module is a collection tank; the combined constructed wetland module consists of multiple It is composed of three-level constructed wetlands, and the multi-level constructed wetlands are arranged in a ladder structure from high to low according to the direction of water flow.

Among them, the filter module is a grid sedimentation tank with a pore size of 5mm, which is used to filter large debris in the sewage; the water distribution module is connected to the combined constructed wetland module and is used to store the sewage in the AOABR module to facilitate different inlets. The water load pumps sewage into the combined constructed wetland module.

In the sewage treatment system of the present invention, an AOABR module is installed before the combined constructed wetland module, which greatly reduces the load of organic matter entering the constructed wetland and effectively reduces the risk of clogging of the constructed wetland. In addition, after the sewage passes through the AOABR module, it not only reduces the nutrient influent load into the combined constructed wetland, but also increases the dissolved oxygen content of the combined constructed wetland influent. Among them, the reduction of the organic matter load of the first-stage saturated flow wetland greatly increases the abundance of autotrophic anammox bacteria, and the increase in the dissolved oxygen content of the influent is also due to the conversion of ammonia nitrogen in the upper layer of the first-stage saturated flow wetland into Nitrate nitrogen and nitrite nitrogen provide conditions, which greatly promotes the first-stage saturated wet subterranean anaerobic ammonia oxidation denitrification, forming a simultaneous denitrification of short-cut nitrification and denitrification and anaerobic ammonia oxidation; at the same time, saturation There are aerobic, anoxic and anaerobic zones in the wetland. The nitrification reaction in the aerobic zone and the anaerobic ammonia oxidation reaction in the anaerobic zone produce nitrate, which is a competitive denitrifying phosphorous under low-carbon conditions. The phosphorus absorption reaction of bacteria in the hypoxic zone provides electron acceptors, thereby enhancing the anaerobic ammonia oxidation denitrification and dephosphorization of domestic sewage by the water treatment system.

The sewage treatment system for enhanced anaerobic ammonia oxidation and dephosphorization of domestic sewage provided by the present invention can remove 98% of COD _Cr , 91.5% of total nitrogen, 98.2% of ammonia nitrogen and 92.7% of total phosphorus in sewage. Among them, the effluent concentration of ammonia nitrogen and COD _Cr can reach the surface water environmental quality standard (GB3838-2002) I to II water, the total phosphorus can reach VI to V, and the total nitrogen can reach V to inferior V.

Preferably, the water inlets of the anaerobic tank, aerobic tank and anoxic tank are all set at the bottom end, and the water outlets are all set at the top end. Wherein, the water inlet of the aerobic tank is connected with the water outlet of the anaerobic tank, and after the water is discharged, it is connected with the water inlet of the anoxic tank; that is, the water flow patterns of the anaerobic tank, aerobic tank, and anoxic tank It is a zigzag style with bottom in and out.

Preferably, both the anaerobic tank and the aerobic tank are provided with polyethylene fillers for the attachment and growth of microorganisms.

Preferably, an aeration pump is provided in the aerobic tank to control the content of organic matter in the aerobic tank and the water quality of the constructed wetland. Wherein, the aeration volume of the aerobic tank is 0.3～0.35m ³ /h, the aeration time is 2～4h/d, the dissolved oxygen concentration is controlled at 2～5mg/L, and the nitrate nitrogen can be removed in the non-aeration stage .

The water inlet mode of the AOABR is batch water inlet, the dissolved oxygen in the anoxic tank is controlled at 0.5-1.5 mg/L in the non-water inlet stage, the nitrate nitrogen can be further removed, and the oxygen-enriched wastewater from the aerobic tank enters through the baffle type In the anoxic tank, the dissolved oxygen in the anoxic tank is controlled at 1.5-4mg/L, and then the oxygenated sewage mainly containing ammonia nitrogen enters the water distribution module through the baffle.

Preferably, the multi-level constructed wetland is a three-level or above constructed wetland.

More preferably, the multi-level constructed wetland is a three-level constructed wetland.

Preferably, the first stage of the multi-stage constructed wetland is a saturated flow wetland; the other stages are saturated flow or unsaturated flow wetlands.

More preferably, the saturated flow wetland is a horizontal subsurface flow constructed wetland or a surface flow constructed wetland; the unsaturated flow wetland is a vertical flow constructed wetland.

That is, the multi-level constructed wetland is a first-level horizontal subsurface flow constructed wetland, a second-level surface flow constructed wetland, and a third-level vertical flow constructed wetland that are sequentially connected from high to low; or the multi-level constructed wetland is from high to low. The first-level surface flow constructed wetland, the second-level vertical flow constructed wetland and the third-level horizontal subsurface flow constructed wetland are sequentially connected.

Preferably, each level of the multi-level constructed wetland is provided with large gravel and small gravel in sequence from bottom to top; wherein the particle size of the large gravel is 2 to 3 cm, and the particle size of the small gravel is 0.5 to 0.5 cm. 1cm; each level of the multi-level constructed wetland is provided with aquatic plants on the surface of the constructed wetland.

More preferably, the aquatic plants are windmill grass, canna and Zai Lihua.

Preferably, the thickness of the gravel in the vertical flow constructed wetland and the horizontal subsurface flow constructed wetland is 60cm, wherein the thickness of the large gravel is 10cm and the thickness of the small gravel is 50cm; the thickness of the gravel in the surface flow constructed wetland is 30cm, Among them, the thickness of the large gravel is 10cm, and the thickness of the small gravel is 20cm.

Preferably, the aeration pump, submersible pump and lifting pump are all controlled by an automatic electronic control system.

Preferably, the top of the water inlet of the sump is connected to the top of the water outlet of the anoxic tank.

Preferably, the water inlet end of the combined constructed wetland module is connected to the water outlet end at the bottom of the water collection tank.

The present invention also claims a method for treating sewage using the above sewage treatment system, which includes the following steps:

Sewage enters the filter module from the water inlet, passes through the grid filter and preliminary sedimentation, is pumped into the AOABR module through the submersible pump, and flows to the water distribution module after AOABR treatment, and then continuously pumped into the combined constructed wetland module through the lift pump, and finally from the water outlet Outflow.

The sewage is domestic sewage, the total nitrogen load of the sewage is preferably 10-50 mg/L, the total phosphorus load is preferably 1-3 mg/L, and the COD _Cr load is preferably 100-400 mg/L. Sewage is pumped into the anaerobic tank in batches after being precipitated by the grid, and then enters the aerobic tank, anoxic tank and the collecting tank in turn through overflow.

Preferably, the way for sewage to enter the AOABR module is batch inflow, once a day; the inflow mode of the water distribution module is batch inflow; the inflow mode of the combined constructed wetland module is continuous inflow, inflow The load is 0.1～0.5m/d.

Preferably, the aeration mode in the aerobic tank is intermittent aeration, the aeration volume is 0.3 to 0.35 m ³ /h, and the aeration time is 2 to 4 hours per day; the dissolved oxygen concentration in the aerobic tank is maintained at 2～5mg/L, nitrate nitrogen can be removed in the non-aeration stage.

More preferably, the aeration time is 2 hours per day.

Preferably, the dissolved oxygen in the anoxic tank is controlled at 0.5-1.5 mg/L during the non-inflow phase, nitrate nitrogen can be further removed, and the oxygen-enriched sewage of the aerobic tank enters the anoxic tank through a baffle, and the anoxic tank is dissolved The oxygen can be controlled at 1.5-4mg/L, and then the oxygenated sewage mainly containing ammonia nitrogen enters the water distribution module through the baffle type.

The present invention uses the above-mentioned sewage treatment system. After the sewage enters the AOABR module and undergoes aeration treatment, the content of organic matter in the combined constructed wetland is greatly reduced, and the risk of clogging of the constructed wetland is effectively reduced; and the combined constructed wetland module is increased after the AOABR module. The dissolved oxygen content of the influent promotes the nitrification of the first-level horizontal flow constructed wetland or the surface flow constructed wetland, thereby providing a substrate for the anaerobic ammonia oxidation reaction that does not depend on the denitrification of organic carbon sources.

Compared with the prior art, the present invention has the following beneficial effects:

(1) Without the addition of external organic carbon sources, the sewage treatment system of the present invention still has a high denitrification and phosphorus removal effect.

(2) The present invention can effectively reduce the content of organic matter entering the constructed wetland, greatly reduce the risk of clogging of the constructed wetland, and prolong the service life of the constructed wetland.

(3) The present invention can effectively reduce the pollution load entering the constructed wetland, greatly reduce the area occupied by the constructed wetland, and solve the disadvantage of using the constructed wetland to treat sewage with a large area.

Description of the drawings

Figure 1 is a schematic diagram of the structure of the sewage treatment system of the present invention.

FIG. 2 is a schematic diagram of the structure of the sewage treatment system of Embodiment 1. FIG.

Fig. 3 is a schematic diagram of the structure of the sewage treatment system of the second embodiment.

Fig. 4 shows changes in the relative abundance of nitrogen conversion function microorganisms in the first-level horizontal subsurface flow constructed wetland (A) and the first-level surface flow constructed wetland (B) with or without the AOABR module in the embodiment of the present invention.

Reference signs: 1-grid sedimentation tank; 2-submersible pump; 3-anaerobic tank; 4-aerobic tank; 5-anoxic tank; 6-polyethylene film-coated packing; 7-aeration pump; 8- Catchment pool; 9-lift pump; 10-horizontal subsurface flow constructed wetland; 11-surface flow constructed wetland; 12-vertical flow constructed wetland; 13-automatic electronic control system.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments. The embodiments are only used to explain the present invention and are not used to limit the scope of the present invention. The test methods used in the following examples are conventional methods unless otherwise specified; the materials and reagents used, unless otherwise specified, are commercially available reagents and materials.

Example 1

A sewage treatment system that strengthens the anaerobic ammonia oxidation and denitrification and dephosphorization of domestic sewage, as shown in Figures 1 and 2, includes a filter module, an AOABR module, a water distribution module, and a combined constructed wetland module connected in sequence; the filter module passes diving Pump 2 is connected to the AOABR module, the water distribution module is connected to the combined constructed wetland module through the lift pump 9; the filter module is provided with water inlets, and the combined constructed wetland module is provided with water outlets; the filter module is the grid sedimentation tank 1; the AOABR module includes sequentially connected Anaerobic tank 3, aerobic tank 4, and anoxic tank 5; the water distribution module is water collection tank 8; the combined constructed wetland module is composed of multi-level constructed wetlands, which are arranged in a ladder structure from high to low according to the direction of water flow; Multi-level constructed wetlands are the first-level horizontal subsurface flow constructed wetland 10 (saturated flow wetland), the second-level surface flow constructed wetland 11 (saturated flow wetland), and the third-level vertical flow constructed wetland 12 (unsaturated flow wetland) connected in sequence from high to low. Wetlands); Multi-level constructed wetlands consist of large gravels and small gravels in order from bottom to top. Among them, the particle size of the large gravel is 2～3cm, and the particle size of the small gravel is 0.5～1cm; There are aquatic plants on the surface of each level of constructed wetland in constructed wetlands; the thickness of gravel in vertical flow constructed wetland 12 and horizontal subsurface flow constructed wetland 10 is 60cm, among which the thickness of large gravel is 10cm, and the thickness of small gravel is 50cm; surface flow The thickness of gravel in constructed wetland 11 is 30cm, among which, the thickness of large gravel is 10cm, and the thickness of small gravel is 20cm; both anaerobic tank 3 and aerobic tank 4 are equipped with polyethylene film-coated packing 6; aerobic tank 4 There is an aeration pump 7; the aeration pump 7, the submersible pump 2 and the lifting pump 9 are all controlled by the automatic electronic control system 13; the top of the water inlet of the collection tank 8 is connected with the outlet of the top of the hypoxic tank 5; combined manual The water inlet end of the wetland module is connected with the water outlet end at the bottom of the collecting basin 8.

Among them, the filter module is a grid sedimentation tank 1 with a pore size of 5mm; the length of the anaerobic tank 3 is 1m, the length of the aerobic tank 4 is 1.7m, the length of the anoxic tank 5 is 0.8m, and the width is 1.26m. , The height is 2.5m; the water capacity of the sump 8 is 2m ³ ; the length, width and height of the first-level horizontal subsurface flow constructed wetland 10, the second-level surface flow constructed wetland 11 and the third-level vertical flow constructed wetland 12 in the combined constructed wetland module They are 0.8m, 0.6m and 0.8m respectively; the aquatic plants are windmill grass, canna and Zaili flower.

In this embodiment, the AOABR module is installed before the combined constructed wetland module, which can accelerate the degradation of organic matter in the sewage, greatly reduce the content of organic matter entering the constructed wetland, thereby reducing the risk of clogging of the constructed wetland, and prolonging the life of the constructed wetland; after passing the AOABR module, The organic matter content entering the combined constructed wetland module is very low, which provides conditions for the growth of autotrophic anammox bacteria; in addition, aeration also increases the dissolved oxygen content of the constructed wetland water, and promotes the first level of subsurface flow in the upper layer of the constructed wetland. The ammonia nitrogen is converted into nitrate nitrogen and nitrite nitrogen, thereby providing conditions for enhancing anaerobic ammonia oxidation denitrification. At the same time, the effluent of the AOABR module creates anoxic zones, aerobic, anoxic and anaerobic zones for the first-level saturated constructed wetland. Nitric acid is produced by the aerobic nitrification reaction and the anaerobic ammonia oxidation reaction in the anaerobic zone. Salt provides electron acceptors for phosphorus accumulating bacteria in the hypoxic zone, thereby strengthening the anaerobic ammonia oxidation denitrification and dephosphorization of domestic sewage by the water treatment system.

A method for treating sewage using the above sewage treatment system includes the following steps:

Sewage enters the filter module from the water inlet, passes grid filtration and preliminary sedimentation, is pumped into the AOABR module through the submersible pump 2 to remove pollutants, and flows to the water distribution module after aeration treatment, and then continuously pumped into the combined constructed wetland through the lift pump 9 The module finally flows out from the water outlet.

Among them, the method of sewage entering the AOABR module is batch inflow, once a day; the inflow method of the water distribution module is batch inflow; the inflow method of the combined constructed wetland module is continuous inflow, and the influent load is 0.1m/ d; The aeration mode of the aerobic tank 4 in the AOABR module is intermittent aeration, the aeration time is 2h per day, the dissolved oxygen concentration in the effluent of the AOABR module is controlled at 1.6～2.8mg/L, and the COD _Cr concentration is controlled at 25～50mg/ L.

The load of total nitrogen in the raw sewage is 20-40mg/L, total phosphorus is 2.5-3.5mg/L, COD _Cr is 150-400mg/L, total nitrogen removal rate is as high as 91.5%, ammonia nitrogen removal rate is as high as 98.2%, total phosphorus The removal rate is as high as 92.7%, and the COD _Cr removal rate is as high as 98%.

Example 2

A sewage treatment system that strengthens the anaerobic ammonia oxidation and denitrification and phosphorus removal of domestic sewage, as shown in Figures 1 and 3, includes a filter module, an AOABR module, a water distribution module and a combined constructed wetland module connected in sequence; the filter module passes diving Pump 2 is connected to the AOABR module, the water distribution module is connected to the combined constructed wetland module through the lift pump 9; the filter module is provided with water inlets, and the combined constructed wetland module is provided with water outlets; the filter module is the grid sedimentation tank 1; the AOABR module includes sequentially connected Anaerobic tank 3, aerobic tank 4, and anoxic tank 5; the water distribution module is water collection tank 8; the combined constructed wetland module is composed of multi-level constructed wetlands, which are arranged in a ladder structure from high to low according to the direction of water flow; Multi-level constructed wetlands are the first-level surface flow constructed wetlands 11, the second-level vertical flow constructed wetlands 12 and the third-level horizontal subsurface flow constructed wetlands 10 that are connected sequentially from high to low; There are large gravels and small gravels in sequence on the upper part. Among them, the particle size of the large gravel is 2 to 3 cm, and the particle size of the small gravel is 0.5 to 1 cm. The surfaces of the constructed wetlands at all levels of the multi-level constructed wetlands are equipped with aquatic plants; vertical flow The thickness of the gravel in the constructed wetland 12 and the horizontal subsurface flow constructed wetland 10 is 60cm, of which the thickness of the large gravel is 10cm and the thickness of the small gravel is 50cm; the thickness of the gravel in the surface flow constructed wetland 11 is 30cm, of which the thickness of the large gravel The thickness of the small gravel is 10cm, and the thickness of the small gravel is 20cm; both the anaerobic tank 3 and the aerobic tank 4 are equipped with polyethylene film-mounted packing 6; the aerobic tank 4 is equipped with aeration pump 7; aeration pump 7, submersible pump 2 Both the lifting pump 9 and the lifting pump 9 are controlled by the automatic electronic control system 13; the top of the water inlet of the sump 8 is connected with the water outlet on the top of the anoxic tank 5; the water inlet of the combined constructed wetland module is connected with the water outlet of the bottom of the sump 8.

Among them, the filter module is a grid sedimentation tank 1 with a pore size of 5mm; the length of the anaerobic tank 3 is 1m, the length of the aerobic tank 4 is 1.7m, the length of the anoxic tank 5 is 0.8m, and the width is 1.26m. , The height is 2.5m; the water capacity of the sump 8 is 2m ³ ; the length, width and height of the first-level surface flow constructed wetland 11, the second-level vertical flow constructed wetland 12 and the third-level horizontal subsurface flow constructed wetland 10 in the combined constructed wetland module They are 0.8m, 0.6m and 0.8m respectively; the aquatic plants are windmill grass, canna and Zaili flower.

In this embodiment, the AOABR module is installed before the combined constructed wetland module, which can accelerate the degradation of organic matter in the sewage, greatly reduce the content of organic matter entering the constructed wetland, thereby reducing the risk of clogging of the constructed wetland, and prolonging the life of the constructed wetland; after passing the AOABR module, The content of organic matter entering the combined constructed wetland module is very low, which provides conditions for the growth of autotrophic anammox bacteria; in addition, aeration also increases the dissolved oxygen content of the constructed wetland’s influent water and promotes the first-level surface flow in the upper layer of the constructed wetland. The ammonia nitrogen is converted into nitrate nitrogen and nitrite nitrogen, thereby providing conditions for enhancing anaerobic ammonia oxidation denitrification. At the same time, the effluent of the AOABR module creates anoxic zones, aerobic, anoxic and anaerobic zones for the first-level saturated constructed wetland. Nitric acid is produced by the aerobic nitrification reaction and the anaerobic ammonia oxidation reaction in the anaerobic zone. Salt provides electron acceptors for phosphorus accumulating bacteria in the hypoxic zone, thereby strengthening the anaerobic ammonia oxidation denitrification and dephosphorization of domestic sewage by the water treatment system.

Among them, the method of sewage entering the AOABR module is batch inflow, once a day; the inflow method of the water distribution module is batch inflow; the inflow method of the combined constructed wetland module is continuous inflow, and the influent load is 0.1m/ d; The aeration mode of the aerobic tank 4 in the AOABR module is intermittent aeration, and the aeration time is 4 hours per day. The concentration of dissolved oxygen in the effluent of the AOABR module is controlled at 1.4～4mg/L, and the concentration of COD _Cr is controlled at 25～50mg/L. .

The load of total nitrogen in raw sewage is 20-40mg/L, total phosphorus is 2.5-3.5mg/L, COD _Cr is 150-400mg/L, total nitrogen removal rate is as high as 92.9%, ammonia nitrogen removal rate is as high as 99.3%, total phosphorus The removal rate is as high as 85.7%, and the COD _Cr removal rate is as high as 95.6%.

As shown in Figure 4, with the AOABR module, the relative abundance of nitrification and anammox functional genes in the first-level saturated constructed wetland is higher or significantly higher than without the AOABR module, but the denitrification functional genes are relatively The abundance is opposite, which further illustrates that the sewage treatment system of the present invention can enhance the denitrification of domestic sewage by improving the anaerobic ammonia oxidation.

In addition, the constructed wetland system of Example 1 and Example 2 showed no blockage after one and a half years of operation.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. For those of ordinary skill in the art, they can also make decisions based on the above descriptions and ideas. For other changes or changes in different forms, it is not necessary and impossible to enumerate all the implementation methods here. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

A sewage treatment system for enhancing the anaerobic ammonia oxidation denitrification and dephosphorization of domestic sewage, which is characterized in that it comprises a filter module, an AOABR module, a water distribution module and a combined constructed wetland module connected in sequence; the filter module passes through a submersible pump ( 2) Connected to the AOABR module, the water distribution module is connected to the combined constructed wetland module through the lift pump (9); the filter module is provided with a water inlet, the combined constructed wetland module is provided with a water outlet; the filter module is a grid sedimentation tank ( 1); The AOABR module includes an anaerobic tank (3), an aerobic tank (4), and an anoxic tank (5) connected in sequence; the water distribution module is a collecting tank (8); the combined constructed wetland module It is composed of multi-level constructed wetlands, which are arranged in a stepped structure according to the direction of water flow from high to low.
The sewage treatment system according to claim 1, wherein the water inlets of the anaerobic tank (3), aerobic tank (4) and anoxic tank (5) are all set at the bottom end, and the water outlets are all set at the bottom top.
The sewage treatment system according to claim 2, wherein the anaerobic tank (3) and the aerobic tank (4) are both equipped with polyethylene filler; the aerobic tank (4) is equipped with aeration Pump (7).
The sewage treatment system according to claim 1, wherein the multi-level constructed wetland is a three-level or more constructed wetland.
The sewage treatment system according to claim 1, wherein the first stage of the multi-stage constructed wetland is a saturated flow wetland; the other stages are a saturated flow or an unsaturated flow wetland.
The sewage treatment system according to claim 1, wherein the aeration pump (7), the submersible pump (2) and the lift pump (9) are all controlled by an automatic electronic control system.
A sewage treatment method, characterized in that, using the sewage treatment system of any one of claims 1 to 6, the sewage enters the filter module from the water inlet, passes through the grid filtration and preliminary sedimentation, and then passes through the submersible pump (2) batch pump Enter the AOABR water treatment module, and flow to the water distribution module after AOABR treatment, and then continuously pump into the combined constructed wetland module through the lift pump (9), and finally flow out from the water outlet.
The sewage treatment method according to claim 7, wherein the water inlet method of the combined constructed wetland module is continuous water inlet, and the water inlet load is 0.1-0.5 m/d.
The sewage treatment method according to claim 7, characterized in that the aeration volume of the aerobic tank (4) is 0.3~0.35m 3 /h, the aeration time is 2~4h/d, and the dissolved oxygen concentration is 2 ~5mg/L.
The sewage treatment method according to claim 7, characterized in that the dissolved oxygen in the anoxic tank (5) is 1.5-4 mg/L, and the dissolved oxygen in the non-water inlet stage is 0.5-1.5 mg/L.