A device for step-by-step denitrification and salt reduction of high-salt and high-nitrogen aquaculture wastewater

Abstract

The utility model belongs to wastewater pretreatment technical field especially, it is a kind of step-by-step denitrification and salt reduction device of high-salt high-nitrogen aquaculture wastewater.The utility model discloses integrated device, integrated device includes the adjusting pool for adjusting water quantity water quality, coagulating sedimentation tank for removing suspended solids, hydrolytic acidification tank for hydrolyzing and acidifying organic matter, secondary biological tank and two sedimentation tank for carrying out mud-water separation connected in turn along water flow direction, the water outlet of two sedimentation tank is connected with clear water pool, the water inlet of adjusting pool is connected with the water outlet of sewage pipe, the sludge discharge port of coagulating sedimentation tank, the sludge discharge port of hydrolytic acidification tank and the sludge discharge port of two sedimentation tank are all connected with the sludge inlet of sludge concentration tank through sludge discharge pipe, the sludge discharge port of two sedimentation tank is also connected with hydrolytic acidification tank and secondary biological tank respectively through sludge backflow pipe.The utility model discloses combined integrated device, saves land occupation, shares pool wall, saves investment, and adopts step-by-step denitrification mechanism: 80% organic nitrogen is removed by one-stage AO, and two-stage AO is in-depth denitrification.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater pretreatment technology, and in particular relates to a stepwise denitrification and desalination device for high-salt and high-nitrogen aquaculture wastewater. Background Technology

[0002] Existing intensive aquaculture processes (such as factory farming and elevated pond farming) generate polluted water bodies containing high concentrations of salt and nitrogen compounds, known as high-salt, high-nitrogen aquaculture wastewater. It is a typical type of high-concentration, difficult-to-treat organic wastewater.

[0003] With increasingly stringent environmental protection requirements, traditional AO processes are becoming insufficient for denitrifying existing high-nitrogen wastewater, especially in high-salt environments (such as Cl-). - >5g / L) will inhibit microbial activity, leading to a significant decrease in the efficiency of traditional biological denitrification (such as nitrification / denitrification). In addition, the carbon-to-nitrogen ratio in aquaculture wastewater is low, resulting in insufficient carbon source in the denitrification process, which in turn leads to sludge bulking and biofilm loss. Furthermore, traditional treatment processes have large fluctuations in water quality and quantity, which can easily lead to system collapse. Utility Model Content

[0004] To overcome the shortcomings of the existing technology, this invention provides a stepwise denitrification and desalination device for high-salinity and high-nitrogen aquaculture wastewater. This invention utilizes salinity gradients to acclimate microorganisms, effectively reducing salinity.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A stepwise denitrification and desalination device for high-salt and high-nitrogen aquaculture wastewater includes an integrated unit. The integrated unit comprises, in sequence along the water flow direction, an equalization tank for regulating water volume and quality, a coagulation sedimentation tank for removing suspended solids, a hydrolysis acidification tank for hydrolyzing and acidifying organic matter, a secondary biological tank, and a secondary sedimentation tank for separating sludge and water. The outlet of the secondary sedimentation tank is connected to a clear water tank, and the inlet of the equalization tank is connected to the outlet of a sewage pipe. The sludge discharge outlets of the coagulation sedimentation tank, the hydrolysis acidification tank, and the secondary sedimentation tank are all connected to the sludge inlet of a sludge thickening tank via sludge discharge pipes. The sludge discharge outlet of the secondary sedimentation tank is also connected to the hydrolysis acidification tank and the secondary biological tank via sludge return pipes.

[0006] Preferably, the equalization tank is equipped with an online pH meter and a stirring device.

[0007] Preferably, the inlet of the coagulation sedimentation tank is connected to the polyaluminum chloride storage tank and the anionic polyacrylamide storage tank.

[0008] Preferably, the hydrolysis acidification tank is filled with elastic three-dimensional packing material, and a first agitator is set at the opposite corner of the hydrolysis acidification tank.

[0009] Preferably, the secondary biological tank includes an anaerobic tank, a first-stage anoxic tank, a first-stage aerobic tank, a second-stage anoxic tank, and a second-stage aerobic tank connected in sequence. The inlet of the anaerobic tank is connected to the outlet of the hydrolysis acidification tank, and the outlet of the second-stage aerobic tank is connected to the inlet of the secondary sedimentation tank.

[0010] Preferably, both the first-stage anoxic tank and the second-stage anoxic tank are equipped with an ORP meter; the anaerobic tank is equipped with a second mixer; both the first-stage aerobic tank and the second-stage aerobic tank are equipped with a dissolved oxygen meter, a sludge concentration meter and a nitrification liquid return pump, and the second-stage aerobic tank is also equipped with an aeration disc.

[0011] Preferably, the sludge discharge port of the secondary sedimentation tank is connected to the sludge inlet of the sludge storage tank, and the sludge discharge port of the sludge storage tank is connected to the hydrolysis acidification tank, the secondary biological tank and the sludge thickening tank through the sludge return pipe. The sludge thickening tank is equipped with a central drive thickener.

[0012] Preferably, the outlet of the sewage pipe is also connected to the inlet of the emergency pool, and the outlet of the emergency pool is connected to the inlet of the regulating pool; the integrated device is 78m long, 20m wide, and 6m high.

[0013] The advantages of this utility model are: (1) This utility model adopts a combined integrated device, which saves space, shares pool walls, and saves investment; and adopts a step-by-step denitrification mechanism: the first stage AO removes 80% of organic nitrogen, and the second stage AO deeply denitrifies.

[0014] (2) This utility model utilizes salinity gradient adaptation: hydrolysis acidification tank → anaerobic + two-stage AO to form a 0.5%-2% salinity gradient to acclimate microorganisms; the use of equalization tank for equalization and equalization of quantity and the use of coagulation sedimentation for pre-treatment can reduce COD load by more than 30% and carry out shock-resistant design. Attached Figure Description

[0015] Figure 1 This is a plan view of the present invention.

[0016] Figure 2 This is a bottom surface layout diagram of the present invention.

[0017] Figure 3 This is a process flow diagram of the present invention.

[0018] The meanings of the symbols in the diagram are as follows: 1-Integrated device, 2-Equalization tank, 3-Emergency tank, 4-Coagulation sedimentation tank, 5-Hydrolysis acidification tank, 6-Anaerobic tank, 7-First stage anoxic tank, 8-First stage aerobic tank, 9-Second stage anoxic tank, 10-Second stage aerobic tank, 11-Sludge thickening tank, 12-Sludge storage tank, 13-Second sedimentation tank, 14-Clear water tank, 15-First mixer, 16-Second mixer. Detailed Implementation

[0019] like Figure 1-3 As shown, a stepwise denitrification and desalination device for high-salt, high-nitrogen aquaculture wastewater includes an integrated device 1. The integrated device 1 comprises, in sequence along the water flow direction, an equalization tank 2, a coagulation sedimentation tank 4, a hydrolysis acidification tank 5 for hydrolyzing and acidifying organic matter, a secondary biological tank, and a secondary sedimentation tank 13 for sludge-water separation. The outlet of the secondary sedimentation tank 13 is connected to a clear water tank 14, and the inlet of the equalization tank 2 is connected to the outlet of a sewage pipe. The sludge discharge port and water outlet of the coagulation sedimentation tank 4 are also connected. The sludge discharge outlets of the hydrolysis acidification tank 5 and the secondary sedimentation tank 13 are both connected to the sludge inlet of the sludge thickening tank 11 via sludge discharge pipes. The sludge discharge outlet of the secondary sedimentation tank 13 is connected to the sludge inlet of the sludge storage tank 12. The sludge discharge outlet of the sludge storage tank 12 is connected to the hydrolysis acidification tank 5, the secondary biological tank, and the sludge thickening tank 11 via sludge return pipes. The sludge thickening tank 11 is equipped with a centrally driven thickener for sludge-water separation, with the effluent flowing to a clear water tank and then discharged into the municipal sewer system. The sludge thickening tank 11 is used for thickening excess sludge.

[0020] Specifically, equalization tank 2 is used to regulate water quantity and quality, ensuring the stability of the influent water quality; coagulation sedimentation tank 4 removes suspended solids and reduces the COD and TP levels of the influent; equalization tank 2 is equipped with an online pH meter and a stirring device, with a hydraulic retention time (HRT) of 4-6 hours. The inlet of coagulation sedimentation tank 4 is connected to a polyaluminum chloride (PAC 50-100 mg / L) storage tank and an anionic polyacrylamide (APAM 1-2 mg / L) storage tank, achieving an SS removal rate of ≥85%. A center-driven sludge scraper is used to avoid the drawbacks of obstructed sludge discharge in vertical flow systems.

[0021] The hydrolysis acidification tank 5 is filled with elastic three-dimensional packing material (specific surface area ≥ 800 m² / m³), DO ≤ 0.5 mg / L, HRT = 8-24 h, which improves the treatment capacity and shock resistance, hydrolyzing and acidifying larger organic molecules into easily degradable smaller organic molecules. A first agitator 15 is installed diagonally in the hydrolysis acidification tank 5, and through counter-current circulation, it further enhances the treatment capacity and shock resistance.

[0022] The secondary biological tank includes an anaerobic tank 6, a first-stage anoxic tank 7, a first-stage aerobic tank 8, a second-stage anoxic tank 9, and a second-stage aerobic tank 10 connected in sequence. The inlet of the anaerobic tank 6 is connected to the outlet of the hydrolysis acidification tank 5, and the outlet of the second-stage aerobic tank 10 is connected to the inlet of the secondary sedimentation tank 13.

[0023] Furthermore, both the first-stage anoxic tank 7 and the second-stage anoxic tank 9 are equipped with ORP meters; the anaerobic tank 6 is equipped with a second mixer 16; and both the first-stage aerobic tank 8 and the second-stage aerobic tank 10 are equipped with dissolved oxygen meters, sludge concentration meters, and nitrification liquor return pumps, enabling intelligent operation. The second-stage aerobic tank 10 is also equipped with aeration discs.

[0024] When the wastewater in equalization tank 2 reaches its treatment capacity, the outlet of the wastewater pipe is connected to emergency tank 3, allowing the wastewater to be temporarily stored in emergency tank 3 before being discharged into equalization tank 2. The integrated device 1 is 78m long, 20m wide, and 6m high.

[0025] The integrated device 1 adopts "equalization tank 2 + coagulation sedimentation tank 4 + hydrolysis acidification packing + A + two-stage AO + sedimentation tank (coagulation sedimentation tank 4 and secondary sedimentation tank 13)", which can meet the conventional indicators of a certain downstream sewage treatment plant's acceptance standards for the pretreatment of aquaculture wastewater and effectively reduce salinity.

[0026] The aeration rate and carbon source addition (such as sodium acetate) are dynamically adjusted by linking the PLC with the ORP meter, dissolved oxygen meter, and sludge concentration meter; the salinity control module automatically starts the dilution system when the influent salinity is >6000mg / L.

[0027] The operation of the device will now be described in detail with reference to the accompanying drawings in the embodiments.

[0028] Taking a certain aquaculture pretreatment station in Yangxin County, Binzhou City as an example, the designed treatment capacity is Q=400m³ / d, and the influent and effluent water quality is as follows:

[0029] This project adopts a combined stepwise denitrification and desalination pretreatment process for high-salinity and high-nitrogen aquaculture wastewater, namely "equalization tank + coagulation sedimentation tank + hydrolysis acidification packing + two-stage AO + sedimentation tank". The combined tank has an overall length of 78m, a width of 20m, and a height of 6m.

[0030] The current water volume is approximately 400 t / d. The influent COD is approximately 4000 mg / L, TN is approximately 1000 mg / L, and the effluent COD is consistently below 330 mg / L, while the effluent TN is consistently below 100 mg / L.

[0031] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A stepwise denitrification and desalination device for high-salinity and high-nitrogen aquaculture wastewater, characterized in that: The device includes an integrated unit (1), which includes an equalization tank (2) for adjusting water volume and quality, a coagulation sedimentation tank (4) for removing suspended solids, a hydrolysis acidification tank (5) for hydrolyzing and acidifying organic matter, a secondary biological tank, and a secondary sedimentation tank (13) for separating sludge and water, connected sequentially along the water flow direction. The outlet of the secondary sedimentation tank (13) is connected to the clear water tank (14), and the inlet of the equalization tank (2) is connected to the outlet of the sewage pipe. The sludge discharge outlets of the coagulation sedimentation tank (4), the hydrolysis acidification tank (5), and the secondary sedimentation tank (13) are all connected to the sludge inlet of the sludge thickening tank (11) through sludge discharge pipes. The sludge discharge outlet of the secondary sedimentation tank (13) is also connected to the hydrolysis acidification tank (5) and the secondary biological tank through sludge return pipes, respectively.

2. The stepwise denitrification and desalination device for high-salinity and high-nitrogen aquaculture wastewater according to claim 1, characterized in that: The regulating tank (2) is equipped with an online pH meter and a stirring device.

3. The stepwise denitrification and desalination device for high-salinity and high-nitrogen aquaculture wastewater according to claim 1, characterized in that: The inlet of the coagulation sedimentation tank (4) is connected to the polyaluminum chloride storage tank and the anionic polyacrylamide storage tank.

4. The stepwise denitrification and desalination device for high-salinity and high-nitrogen aquaculture wastewater according to claim 1, characterized in that: The hydrolysis acidification tank (5) is filled with elastic three-dimensional packing material, and a first agitator (15) is set diagonally in the hydrolysis acidification tank (5).

5. The stepwise denitrification and desalination device for high-salinity and high-nitrogen aquaculture wastewater according to claim 1, characterized in that: The secondary biological tank includes an anaerobic tank (6), a first-stage anoxic tank (7), a first-stage aerobic tank (8), a second-stage anoxic tank (9), and a second-stage aerobic tank (10) connected in sequence. The inlet of the anaerobic tank (6) is connected to the outlet of the hydrolysis acidification tank (5), and the outlet of the second-stage aerobic tank (10) is connected to the inlet of the secondary sedimentation tank (13).

6. The stepwise denitrification and desalination device for high-salinity and high-nitrogen aquaculture wastewater according to claim 5, characterized in that: Both the first-stage anoxic tank (7) and the second-stage anoxic tank (9) are equipped with ORP meters; the anaerobic tank (6) is equipped with a second mixer (16); both the first-stage aerobic tank (8) and the second-stage aerobic tank (10) are equipped with dissolved oxygen meters, sludge concentration meters and nitrification liquid return pumps, and the second-stage aerobic tank (10) is also equipped with aeration discs.

7. The stepwise denitrification and desalination device for high-salinity and high-nitrogen aquaculture wastewater according to claim 1, characterized in that: The sludge discharge port of the secondary sedimentation tank (13) is connected to the sludge inlet of the sludge storage tank (12). The sludge discharge port of the sludge storage tank (12) is connected to the hydrolysis acidification tank (5), the secondary biological tank and the sludge thickening tank (11) through the sludge return pipe. The sludge thickening tank (11) is equipped with a central drive thickener.

8. The stepwise denitrification and desalination device for high-salinity and high-nitrogen aquaculture wastewater according to claim 1, characterized in that: The outlet of the sewage pipe is also connected to the inlet of the accident pool (3), and the outlet of the accident pool (3) is connected to the inlet of the regulating pool (2); the integrated device (1) is 78m long, 20m wide, and 6m high.

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