Zero-carbon-source domestic sewage nitrogen and phosphorus removal device

Abstract

The utility model relates to the technical field of water treatment, in particular to a zero-carbon-source domestic sewage nitrogen and phosphorus removal device which comprises a digestion tank, an anoxic tank, an aerobic tank, a low-oxygen tank and a secondary sedimentation tank, the digestion tank is respectively connected with a water inlet pipe and a sludge return pipe, a nitrification liquid return pump is arranged on a nitrification liquid return pipe, effluent of the anoxic tank enters the aerobic tank from a bottom water passing hole, a tubular aerator is arranged at the bottom of the aerobic tank, and effluent of the aerobic tank enters the low-oxygen tank through an upper water passing hole. Effluent enters a secondary sedimentation tank through a communicating pipe for mud-water separation, and the secondary sedimentation tank is connected with a water outlet pipe for discharging. By arranging the digestion tank, macromolecular organic matters difficult to degrade in water are converted into an internal carbon source for storage, the carbon source in the sewage is fully utilized, urban domestic sewage does not need an external carbon source, the effluent quality can meet the standard IV of surface water, and meanwhile, the process is low in sludge yield, good in effluent quality effect and low in cost. The overall operation cost of the process is low.

Description

Technical Field

[0001] The utility model relates to the technical field of water treatment, in particular to a zero-carbon source domestic sewage denitrification and dephosphorization device. Background Art

[0002] Although the traditional biological denitrification and phosphorus removal process has a good removal effect on nitrogen and phosphorus, and has played an important role in sewage denitrification and phosphorus removal in a certain period of time, these processes are designed based on traditional denitrification and phosphorus removal. Biological denitrification of sewage is mainly achieved through aerobic / anoxic nitrification and denitrification reactions;

[0003] Biological phosphorus removal is mainly achieved through anaerobic / aerobic phosphorus release and absorption reactions. The sewage carbon source is insufficient, there is carbon source competition in nitrogen and phosphorus removal, the nitrogen and phosphorus removal efficiency is low, the nitrate nitrogen carried by the return sludge destroys the anaerobic phosphorus release environment, the return nitrification liquid carries a high level of dissolved oxygen, which destroys the anoxic denitrification environment, and the return energy consumption is high. The high nitrate nitrogen concentration in the effluent causes the total nitrogen to exceed the standard. Utility Model Content

[0004] The utility model aims to solve the shortcomings in the prior art and proposes a zero-carbon source domestic sewage denitrification and dephosphorization device.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] Design a zero-carbon source domestic sewage denitrification and phosphorus removal device, including a digestion tank, an anoxic tank, an aerobic tank, a hypoxic tank and a secondary sedimentation tank;

[0007] The digester is connected to a water inlet pipe and a return sludge pipe respectively, and the incoming water in the water inlet pipe and the return sludge in the return sludge pipe are mixed and enter the digester through the perforated water distribution pipe at the bottom of the tank;

[0008] The effluent from the digester overflows into the anoxic tank, and the upper part of the anoxic tank is simultaneously connected to a nitrification liquid reflux pipe, on which a nitrification liquid reflux pump is arranged. The effluent from the anoxic tank enters the aerobic tank from the bottom water hole, and a tubular aerator is arranged at the bottom of the aerobic tank. The effluent from the aerobic tank enters the hypoxic tank through the upper water hole, and the effluent enters the secondary sedimentation tank through a connecting pipe for mud-water separation, and the secondary sedimentation tank is connected with an outlet pipe for discharge.

[0009] Preferably, the digester is provided with a perforated water distribution pipe to mix the incoming water and the return sludge and distribute the water evenly.

[0010] Preferably, the dissolution in the hypoxic pool is controlled within 1.0 mg / L, and the residence time is controlled within 2 hours.

[0011] Preferably, the dissolution in the anoxic tank is controlled at 0.5 mg / Lmg / L, and the residence time is controlled within 6 hours.

[0012] Preferably, submersible flow propellers are provided in the hypoxic pool and the anoxic pool.

[0013] The utility model proposes a zero-carbon source domestic sewage denitrification and phosphorus removal device, which has the beneficial effects of: the zero-carbon source domestic sewage denitrification and phosphorus removal device, by arranging a digester, converts the difficult-to-degrade macromolecular organic matter in the water into internal carbon source storage, fully utilizes the carbon source in the sewage, and truly does not require an external carbon source for urban domestic sewage. The effluent water quality can meet the surface water level IV standard. At the same time, the process has low sludge output, good effluent water quality, and low overall process operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic structural diagram of a zero-carbon source domestic sewage denitrification and dephosphorization device proposed by the utility model.

[0015] Figure 2 The present invention is a flow chart of a zero-carbon source domestic sewage denitrification and dephosphorization device proposed by the utility model.

[0016] In the figure: digester 1, anoxic tank 2, aerobic tank 3, hypoxic tank 4, return sludge pipe 5, water inlet pipe 6, nitrification liquid return pump 7, nitrification liquid return pipe 8, tubular aerator 9, submersible flow propeller 10, outlet pipe 11, perforated water distribution pipe 12. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0018] Reference Figure 1-2 , a zero-carbon source domestic sewage denitrification and phosphorus removal device, comprising a digestion tank 1, an anoxic tank 2, an aerobic tank 3, a hypoxic tank 4 and a secondary sedimentation tank;

[0019] The digester 1 is connected to a water inlet pipe 6 and a return sludge pipe 5 respectively. The incoming water in the water inlet pipe 6 and the return sludge in the return sludge pipe 5 are mixed and enter the digester 1 through the perforated water distribution pipe 12 at the bottom of the tank.

[0020] The effluent from the digester 1 overflows into the anoxic tank 2. The upper part of the anoxic tank 2 is simultaneously connected to a nitrification liquid reflux pipe 8. A nitrification liquid reflux pump 7 is provided on the nitrification liquid reflux pipe 8. The effluent from the anoxic tank 2 enters the aerobic tank 3 through a water hole at the bottom. A tubular aerator 9 is provided at the bottom of the aerobic tank 3. The effluent from the aerobic tank 3 enters the hypoxic tank 4 through an upper water hole. The effluent enters the secondary sedimentation tank through a connecting pipe for mud-water separation. The secondary sedimentation tank is connected to an outlet pipe 11 for discharge.

[0021] A perforated water distribution pipe 12 is provided in the digester 1 to mix the incoming water and the return sludge and distribute the water evenly.

[0022] The dissolution in hypoxic pool 4 is controlled within 1.0 mg / L, and the residence time is controlled within 2 h.

[0023] The dissolution in anoxic pool 2 is controlled at 0.5mg / Lmg / L, and the residence time is controlled within 6h.

[0024] Submersible flow propellers 10 are provided in the hypoxic pool 4 and the anoxic pool 2 .

[0025] The working principle of the device is:

[0026] The sewage passes through the digestion tank 1, the anoxic tank 2, the aerobic tank 3 and the hypoxic tank 4 in sequence. The incoming water is mixed with the return sludge in the return sludge pipe 5 through the water inlet pipe 6 in the perforated water distribution pipe 12, and is evenly distributed in the digestion tank 1 through the perforated water distribution pipe 12 at the bottom of the tank, ensuring that the incoming water is fully in contact with the return sludge.

[0027] At the same time, through digestion, microorganisms adsorb and transform the difficult-to-degrade organic matter in the water in the cell body, and store it in the form of glycogen and internal carbon source. The effluent of the digestion tank 1 overflows into the anoxic tank 2. The upper part of the anoxic tank 2 is simultaneously connected to the nitrification liquid return pipe 8. The sewage in the anoxic tank 2 uses the nitrate nitrogen molecular oxygen in the nitrification liquid to carry out denitrification reaction. The anoxic tank 2 completes the full mixing of the nitrification liquid, the incoming water and the return sludge mixed liquid through the submersible flow propeller 10;

[0028] The effluent from the anoxic pool 2 enters the aerobic pool 3 through the water hole at the bottom. A tubular aerator (9) is provided at the bottom of the aerobic pool 3. Through aeration, microorganisms consume the internal carbon source in the aerobic pool 3 to complete aerobic phosphorus absorption and nitrification reactions.

[0029] The effluent from the aerobic tank 3 enters the hypoxic tank 4 through the upper water hole. A submersible flow propeller 10 is provided in the hypoxic tank 4 to ensure that the mixed liquid is fully mixed. In the hypoxic tank 4, microorganisms consume the carbon source in their bodies to further remove nitrate nitrogen in the incoming water, while reducing the dissolved oxygen in the return sludge and nitrification liquid return, thereby improving the denitrification reaction efficiency. Part of the effluent is returned to the anoxic tank 2 through the nitrification liquid return pump 7 for denitrification and denitrification, and part of it enters the secondary sedimentation tank through the outlet pipe 11 for mud and water separation, and the effluent meets the discharge standards.

[0030] At the same time, the period includes two reflows, namely, sludge reflow and nitrification liquid reflow. The sludge reflow returns the sludge at the bottom of the secondary sedimentation tank to the anoxic tank 2, and the sludge reflow ratio does not exceed 80%. The nitrification liquid reflow is the nitrification liquid effluent from the hypoxic tank 4 returned to the anoxic tank 2, and the nitrification liquid reflow ratio is controlled at 200%-300%.

[0031] The digester 1 is used to cultivate the biological abundance of Tetrasphaera microorganisms. At the same time, a deep anaerobic environment is created by the digester 1. Tetrasphaera microorganisms can directly use the large molecular protein and sugar positions for hydrolysis and fermentation to generate internal carbon source storage. At the same time, traditional polyphosphate bacteria and other microorganisms can also absorb unsaturated volatile fatty acids in the incoming water to store phb in this environment, thereby increasing the internal carbon source content in the microorganisms.

[0032] Tetrasphaera, also known as Tetrasphaera, is a genus of bacteria belonging to the phylum Actinomycetes and the family Endomycetes.

[0033] In the anoxic tank 2, the microorganisms in the denitrification stage can not only utilize the undegraded biodegradable organic matter in the water for denitrification, but also utilize the internal carbon source for denitrification when the external carbon source is insufficient, thereby reducing the demand for external carbon sources; in the aerobic stage, the microorganisms consume the internal carbon source in the body for aerobic phosphorus absorption, avoiding the interference of external carbon sources on nitrifying bacteria, achieving the ultimate phosphorus removal effect and strengthening the nitrification reaction; in the hypoxic stage, the microorganisms consume the internal carbon source in the body for further denitrification, thereby improving the denitrification efficiency and reducing the denitrification burden of the anoxic tank.

[0034] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A zero-carbon source domestic sewage denitrification and dephosphorization device, comprising a digestion tank (1), an anoxic tank (2), an aerobic tank (3), a hypoxic tank (4) and a secondary sedimentation tank, characterized in that ； The digester (1) is respectively connected to a water inlet pipe (6) and a return sludge pipe (5); the incoming water in the water inlet pipe (6) and the return sludge in the return sludge pipe (5) are mixed and enter the digester (1) through a perforated water distribution pipe (12) at the bottom of the tank; The effluent from the digestion tank (1) overflows into the anoxic tank (2). The upper part of the anoxic tank (2) is simultaneously connected to a nitrification liquid return pipe (8). The nitrification liquid return pipe (8) is provided with a nitrification liquid return pump (7). The effluent from the anoxic tank (2) enters the aerobic tank (3) through a water hole at the bottom. A tubular aerator (9) is provided at the bottom of the aerobic tank (3). The effluent from the aerobic tank (3) enters the hypoxic tank (4) through an upper water hole. The effluent enters the secondary sedimentation tank through a connecting pipe for mud and water separation. The secondary sedimentation tank is connected with an outlet pipe (11) for discharge.

2. The zero-carbon source domestic sewage denitrification and dephosphorization device according to claim 1 is characterized in that: The digester (1) is provided with a perforated water distribution pipe (12) for mixing incoming water and return sludge and distributing the water evenly.

3. The zero-carbon source domestic sewage denitrification and dephosphorization device according to claim 2 is characterized in that: The dissolution of the hypoxic pool (4) is controlled within 1.0 mg / L, and the residence time is controlled within 2 hours.

4. The zero-carbon source domestic sewage denitrification and dephosphorization device according to claim 3 is characterized in that: The dissolution in the anoxic pool (2) is controlled at 0.5 mg / Lmg / L, and the residence time is controlled within 6 hours.

5. The zero-carbon source domestic sewage denitrification and dephosphorization device according to claim 4, characterized in that: Submersible flow propellers (10) are provided in the hypoxic pool (4) and the anoxic pool (2).

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