Advanced sewage treatment system for carbon removal and nitrification

Abstract

The utility model discloses an advanced sewage treatment system for carbon removal and nitrification, belongs to the technical field of sewage treatment, and solves the problems of difficulty in treatment and higher total nitrogen concentration caused by low concentration of organic matters in secondary effluent of an urban sewage plant. The device comprises a first-stage anoxic filter tank, a first-stage aerobic filter tank, a second-stage anoxic filter tank and a second-stage aerobic filter tank which are connected in sequence, the bottom of the primary anoxic filter is connected with a first water inlet pipe, the bottom of the secondary anoxic filter is connected with a second water inlet pipe, a first communicating pipe is arranged between the bottom of the primary aerobic filter and the primary anoxic filter, and a second communicating pipe is arranged between the bottom of the secondary anoxic filter and the primary aerobic filter; and a third communicating pipe is arranged between the bottom of the second-stage aerobic filter tank and the second-stage anoxic filter tank. According to the utility model, the upward flow filter tank is adopted, so that the filter speed is high, the water treatment capacity is large, the filter material assimilative capacity is strong, the water loss is small and the filter period is long; and the design of multi-point water inlet can improve the sewage treatment capacity, and further purification of the secondary effluent quality is better realized.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, specifically relating to a deep wastewater treatment system for carbon removal and nitrification. Background Technology

[0002] Northwest China is a typical arid and semi-arid region, with low annual rainfall leading to water scarcity. Wastewater reuse is of great significance in alleviating the pressure on water body restoration. The market potential for urban wastewater resource utilization is enormous. According to relevant institutions, my country's reclaimed water scale is expected to reach 85 million cubic meters by 2025. 3 With an estimated annual growth rate of approximately 100 billion yuan, the transformation of existing wastewater treatment plants and the construction of new reclaimed water plants are expected to create a market space worth hundreds of billions of yuan in related fields over the next five years.

[0003] In Northwest China, the main wastewater treatment methods used in urban wastewater treatment plants include activated sludge and biofilm processes. Taking the typical AO process as an example, it often suffers from low denitrification rates. While the improved AO process pre-positions denitrification, resulting in some improvement in denitrification efficiency, issues such as sludge floating in sedimentation tanks can still occur if nitrate nitrogen cannot be returned in time. After primary and secondary treatment, some urban wastewater treatment plants produce effluent with low organic matter concentrations, but the total nitrogen concentration often fails to meet the "Surface Water Environmental Quality Standard" (GB3838-2002). Utility Model Content

[0004] The purpose of this invention is to provide a wastewater deep treatment system for carbon removal and nitrification, in order to solve the problems of low organic matter concentration and high total nitrogen concentration in the secondary effluent of urban wastewater treatment plants.

[0005] The technical solution of this utility model is: a wastewater deep treatment system for carbon removal and nitrification, including an AO biological filter group, which includes a primary anoxic filter, a primary aerobic filter, a secondary anoxic filter, and a secondary aerobic filter connected in sequence.

[0006] The bottom of the primary anoxic filter is provided with a primary anoxic filter inlet, which is connected to a first inlet pipe. The first inlet pipe is equipped with a first inlet pump and a first inlet valve.

[0007] The bottom of the secondary anoxic filter is equipped with a secondary anoxic filter inlet, which is connected to a second inlet pipe. The second inlet pipe is equipped with a second inlet pump and a second inlet valve.

[0008] The upper side wall of the primary anoxic filter is provided with the primary anoxic filter outlet, the bottom of the primary aerobic filter is provided with the primary aerobic filter inlet, and a first connecting pipe is provided between the primary anoxic filter outlet and the primary aerobic filter inlet.

[0009] The upper side wall of the primary aerobic filter is provided with the primary aerobic filter outlet, and the bottom of the secondary anoxic filter is provided with the secondary anoxic filter inlet. A second connecting pipe is provided between the primary aerobic filter outlet and the secondary anoxic filter inlet.

[0010] The upper side wall of the secondary anoxic filter is provided with the outlet of the secondary anoxic filter, the bottom of the secondary aerobic filter is provided with the inlet of the secondary aerobic filter, and a third connecting pipe is provided between the outlet of the secondary anoxic filter and the inlet of the secondary aerobic filter.

[0011] The upper side wall of the secondary aerobic filter is equipped with a secondary aerobic filter outlet, which is connected to an outlet pipe with an outlet valve.

[0012] As a further improvement of this utility model, the first inlet pump is connected to a first bypass pipe at both ends, and a first bypass valve is provided on the first bypass pipe; the second inlet pump is connected to a second bypass pipe at both ends, and a second bypass valve is provided on the second bypass pipe.

[0013] As a further improvement of this utility model, it includes two AO biological filter groups, which are connected in parallel.

[0014] As a further improvement of this utility model, it also includes a backwash pipe and an overflow pipe;

[0015] A backwash pump is installed on the backwash pipe, which is connected to a first backwash branch pipe, a second backwash branch pipe, a third backwash branch pipe, and a fourth backwash branch pipe. The first backwash branch pipe is connected to the inlet of the first-stage anoxic filter and is equipped with a first backwash valve. The second backwash branch pipe is connected to the inlet of the first-stage aerobic filter and is equipped with a second backwash valve. The third backwash branch pipe is connected to the inlet of the second-stage anoxic filter and is equipped with a third backwash valve. The fourth backwash branch pipe is connected to the inlet of the second-stage aerobic filter and is equipped with a fourth backwash valve.

[0016] The upper sidewall of the primary anoxic filter is equipped with an overflow outlet for the primary anoxic filter, the upper sidewall of the primary aerobic filter is equipped with an overflow outlet for the primary aerobic filter, the upper sidewall of the secondary anoxic filter is equipped with an overflow outlet for the secondary anoxic filter, and the upper sidewall of the secondary aerobic filter is equipped with an overflow outlet for the secondary aerobic filter. The overflow pipe is equipped with multiple overflow branches, which are connected one-to-one with the overflow outlets of the primary anoxic filter, the primary aerobic filter, the secondary anoxic filter, and the secondary aerobic filter.

[0017] As a further improvement of this utility model, it also includes an air supply pipe, an air supply pump on the air supply pipe, and multiple air supply branch pipes on the air supply pipe. The air supply branch pipes are connected one-to-one to the first-stage anoxic filter, the first-stage aerobic filter, the second-stage anoxic filter, and the second-stage aerobic filter. An air supply valve is provided on the air supply branch pipe.

[0018] As a further improvement of this utility model, an air flow meter is installed on the air supply branch pipe connected to the primary aerobic filter and the secondary aerobic filter.

[0019] As a further improvement of this utility model, the inlet of the first-stage anoxic filter is also connected to a first vent pipe, and the first vent pipe is equipped with a first vent valve; the inlet of the first-stage aerobic filter is also connected to a second vent pipe, and the second vent pipe is equipped with a second vent valve; the inlet of the second-stage anoxic filter is also connected to a third vent pipe, and the third vent pipe is equipped with a third vent valve; the inlet of the second-stage aerobic filter is also connected to a fourth vent pipe, and the fourth vent pipe is equipped with a fourth vent valve.

[0020] As a further improvement of this utility model, two first connecting valves are provided on the first connecting pipe, and a first emergency pipe is provided between the first connecting pipes of the two AO biological filter groups. The first emergency pipe is connected between the two first connecting valves and a first emergency valve is provided on the first emergency pipe.

[0021] The second connecting pipe is equipped with two second connecting valves. A second emergency pipe is provided between the second connecting pipes of the two AO biological filter groups. The second emergency pipe is connected between the two second connecting valves and is equipped with a second emergency valve.

[0022] Two third connecting valves are provided on the third connecting pipe. A third emergency pipe is provided between the third connecting pipes of the two AO biological filter groups. The third emergency pipe is connected between the two third connecting valves and is equipped with a third emergency valve.

[0023] As a further improvement of this utility model, the internal structure of the primary anoxic filter, the primary aerobic filter, the secondary anoxic filter, and the secondary aerobic filter is the same, and from bottom to top, they are provided with a perforated water distribution plate, a pebble cushion layer, and a filter media area; the primary anoxic filter and the secondary anoxic filter are provided with a cover plate on the top; the primary aerobic filter and the secondary aerobic filter have an open structure on the top.

[0024] As a further improvement of this utility model, the heights of the first-stage anoxic filter, the first-stage aerobic filter, the second-stage anoxic filter, and the second-stage aerobic filter decrease sequentially.

[0025] The beneficial effects of this utility model are:

[0026] 1. Unlike the traditional downflow filter structure used in the secondary effluent treatment of urban domestic sewage, the primary anoxic filter, primary aerobic filter, secondary anoxic filter, and secondary aerobic filter in this utility model adopt an upflow filter. The filter media particles are in a suspended state, which makes them less prone to clogging. The filtration rate is high, the water treatment capacity is large, the filter media has a strong dirt holding capacity, the water loss is small, the filtration cycle is long, and the backwashing frequency is low, which helps to reduce operating energy consumption.

[0027] 2. The elevation of this utility model can be higher or lower than the secondary treatment structure. When higher than the secondary treatment structure, the secondary effluent is pumped to the primary and secondary anoxic filters by the first and second inlet pumps. When lower than the secondary treatment structure, the first and second bypass valves can be opened, eliminating the need for the first and second inlet pumps. The secondary effluent can then flow by gravity into the primary and secondary anoxic filters, maximizing the utilization of the head of the secondary treatment structure, avoiding energy input, and reducing system energy consumption.

[0028] 3. In this utility model, the first-stage anoxic filter, the first-stage aerobic filter, the second-stage anoxic filter, and the second-stage aerobic filter are arranged in a stepped manner with decreasing elevations. Water can flow in from front to back by gravity without the need for additional energy input, thus saving energy consumption.

[0029] 4. This utility model sets up two AO biological filter groups in parallel. When one filter is under maintenance or backwashing, it can be shut down and the water can be diverted to the corresponding filter of the other AO biological filter group. This achieves uninterrupted production during maintenance and backwashing and avoids reduced water plant production during maintenance or backwashing.

[0030] 5. This utility model innovatively combines the process characteristics of AOAO activated sludge wastewater treatment with those of biological filters, utilizing the respective advantages of the activated sludge and biofilm processes. In addition, the multi-point influent design of the primary and secondary anoxic filters can improve wastewater treatment capacity and better achieve further purification of the secondary effluent. The AO biological filter group removes organic matter through adsorption and partial biodegradation, requiring less organic matter and solving the problems of low organic matter concentration in the secondary effluent leading to difficult treatment and high total nitrogen concentration. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the planar structure of this utility model;

[0032] Figure 2 This is a schematic diagram of the AO biological filter group in this utility model;

[0033] Figure 3 This is an exploded view of the internal structure of the primary anoxic filter in this utility model.

[0034] In the diagram: 1 - Secondary treatment structure; 101 - First inlet pump; 102 - First inlet valve; 104 - First inlet pipe; 105 - Second inlet pump; 106 - Second inlet valve; 108 - Second inlet pipe; 109 - First bypass pipe; 110 - First bypass valve; 111 - Second bypass pipe; 112 - Second bypass valve; 113 - First connecting pipe; 114 - First connecting valve; 115 - Second connecting pipe; 116 - Second connecting valve; 117 - Third connecting pipe; 118 - Third connecting valve; 119 - Outlet pipe; 20-Overflow pipe; 121-First emergency pipe; 122-First emergency valve; 123-Second emergency pipe; 124-Second emergency valve; 125-Third emergency pipe; 126-Third emergency valve; 127-Overflow branch pipe; 128-Outlet valve; 2-First-stage anoxic filter; 204-Outlet of first-stage anoxic filter; 207-Overflow outlet of first-stage anoxic filter; 208-Inlet of first-stage anoxic filter; 3-First-stage aerobic filter; 304-Outlet of first-stage aerobic filter; 307-Overflow outlet of first-stage aerobic filter; 308-Inlet of first-stage aerobic filter 4 - Water inlet; 404 - Secondary anoxic filter; 407 - Secondary anoxic filter outlet; 408 - Secondary anoxic filter overflow outlet; 5 - Secondary aerobic filter; 504 - Secondary aerobic filter outlet; 507 - Secondary aerobic filter overflow outlet; 508 - Secondary aerobic filter inlet; 601 - Backwash pump; 602 - First backwash branch pipe; 603 - First backwash valve; 604 - Second backwash branch pipe; 605 - Second backwash valve; 606 - Third backwash branch pipe; 607 - Third backwash valve; 608-Fourth backwash branch pipe; 609-Fourth backwash valve; 610-Backwash pipe; 701-Air supply pump; 702-Air supply pipe; 703-Air supply branch pipe; 704-Air supply valve; 705-Air flow meter; 801-Filter media area; 802-Pebble pad; 803-Perforated water distribution plate; 901-First vent pipe; 903-First vent valve; 904-Second vent pipe; 906-Second vent valve; 907-Third vent pipe; 909-Third vent valve; 910-Fourth vent pipe; 912-Fourth vent valve. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings.

[0036] like Figure 1-3 As shown, a wastewater deep treatment system for carbon removal and nitrification includes an AO biological filter group, which includes a primary anoxic filter 2, a primary aerobic filter 3, a secondary anoxic filter 4, and a secondary aerobic filter 5 connected in sequence.

[0037] The bottom of the primary anoxic filter 2 is provided with a primary anoxic filter inlet 208, which is connected to a first inlet pipe 104. The first inlet pipe 104 is provided with a first inlet pump 101 and a first inlet valve 102.

[0038] The bottom of the secondary anoxic filter 4 is provided with a secondary anoxic filter inlet 408, and the secondary anoxic filter inlet 408 is connected to a second inlet pipe 108. The second inlet pipe 108 is provided with a second inlet pump 105 and a second inlet valve 106.

[0039] The upper side wall of the first-stage anoxic filter 2 is provided with a first-stage anoxic filter outlet 204, and the bottom of the first-stage aerobic filter 3 is provided with a first-stage aerobic filter inlet 308. A first connecting pipe 113 is provided between the first-stage anoxic filter outlet 204 and the first-stage aerobic filter inlet 308.

[0040] The upper side wall of the primary aerobic filter 3 is provided with a primary aerobic filter outlet 304, and the bottom of the secondary anoxic filter 4 is provided with a secondary anoxic filter inlet 408. A second connecting pipe 115 is provided between the primary aerobic filter outlet 304 and the secondary anoxic filter inlet 408.

[0041] The upper side wall of the secondary anoxic filter 4 is provided with a secondary anoxic filter outlet 404, the bottom of the secondary aerobic filter 5 is provided with a secondary aerobic filter inlet 508, and a third connecting pipe 117 is provided between the secondary anoxic filter outlet 404 and the secondary aerobic filter inlet 508.

[0042] The upper side wall of the secondary aerobic filter 5 is provided with a secondary aerobic filter outlet 504, and the secondary aerobic filter outlet 504 is connected to an outlet pipe 119, and an outlet valve 128 is provided on the outlet pipe 119.

[0043] The first inlet pump 101 is connected to the first bypass pipe 109 at both ends, and the first bypass pipe 109 is equipped with a first bypass valve 110; the second inlet pump 105 is connected to the second bypass pipe 111 at both ends, and the second bypass pipe 111 is equipped with a second bypass valve 112.

[0044] The system includes two AO biological filter groups, which are connected in parallel.

[0045] It also includes a backflushing pipe 610 and an overflow pipe 120;

[0046] A backwash pump 601 is installed on the backwash pipe 610. The backwash pipe 610 is connected to a first backwash branch pipe 602, a second backwash branch pipe 604, a third backwash branch pipe 606, and a fourth backwash branch pipe 608. The first backwash branch pipe 602 is connected to the inlet 208 of the first-stage anoxic filter and is equipped with a first backwash valve 603. The second backwash branch pipe 604 is connected to the inlet 308 of the first-stage aerobic filter and is equipped with a second backwash valve 605. The third backwash branch pipe 606 is connected to the inlet 408 of the second-stage anoxic filter and is equipped with a third backwash valve 607. The fourth backwash branch pipe 608 is connected to the inlet 508 of the second-stage aerobic filter and is equipped with a fourth backwash valve 609.

[0047] The upper sidewall of the primary anoxic filter 2 is equipped with an overflow outlet 207, which is higher than the outlet of the primary anoxic filter. The upper sidewall of the primary aerobic filter 3 is equipped with an overflow outlet 307, which is higher than the outlet of the primary aerobic filter. The upper sidewall of the secondary anoxic filter 4 is equipped with an overflow outlet 407, which is higher than the outlet of the secondary anoxic filter. The filter outlet 404; the upper side wall of the secondary aerobic filter 5 is provided with a secondary aerobic filter overflow outlet 507, which is higher than the secondary aerobic filter outlet 504; the overflow pipe 120 is provided with multiple overflow branch pipes 127, which are connected one-to-one with the primary anoxic filter overflow outlet 207, the primary aerobic filter overflow outlet 307, the secondary anoxic filter overflow outlet 407, and the secondary aerobic filter overflow outlet 507.

[0048] It also includes an air supply pipe 702, an air supply pump 701 on the air supply pipe 702, and multiple air supply branch pipes 703 on the air supply pipe 702. The air supply branch pipes 703 are connected one-to-one to the primary anoxic filter 2, the primary aerobic filter 3, the secondary anoxic filter 4, and the secondary aerobic filter 5. An air supply valve 704 is provided on the air supply branch pipes 703.

[0049] An air flow meter 705 is installed on the air supply branch pipe 703 that connects to the primary aerobic filter 3 and the secondary aerobic filter 5.

[0050] The inlet 208 of the primary anoxic filter is also connected to a first vent pipe 901, which is equipped with a first vent valve 903; the inlet 308 of the primary aerobic filter is also connected to a second vent pipe 904, which is equipped with a second vent valve 906; the inlet 408 of the secondary anoxic filter is also connected to a third vent pipe 907, which is equipped with a third vent valve 909; and the inlet 508 of the secondary aerobic filter is also connected to a fourth vent pipe 910, which is equipped with a fourth vent valve 912.

[0051] Two first connecting valves 114 are provided on the first connecting pipe 113. A first emergency pipe 121 is provided between the first connecting pipes 113 of the two AO biological filter groups. The first emergency pipe 121 is connected between the two first connecting valves 114. A first emergency valve 122 is provided on the first emergency pipe 121.

[0052] Two second connecting valves 116 are provided on the second connecting pipe 115. A second emergency pipe 123 is provided between the second connecting pipes 115 of the two AO biological filter groups. The second emergency pipe 123 is connected between the two second connecting valves 116. A second emergency valve 124 is provided on the second emergency pipe 123.

[0053] Two third connecting valves 118 are provided on the third connecting pipe 117. A third emergency pipe 125 is provided between the third connecting pipes 117 of the two AO biological filter groups. The third emergency pipe 125 is connected between the two third connecting valves 118. A third emergency valve 126 is provided on the third emergency pipe 125.

[0054] The primary anoxic filter 2, primary aerobic filter 3, secondary anoxic filter 4, and secondary aerobic filter 5 have the same internal structure, and from bottom to top, they are provided with a perforated water distribution plate 803, a pebble cushion layer 802, and a filter media zone 801. The primary anoxic filter 2 and secondary anoxic filter 4 are covered with a cover plate. The primary aerobic filter 3 and secondary aerobic filter 5 have an open top structure.

[0055] The heights of the primary anoxic filter 2, primary aerobic filter 3, secondary anoxic filter 4, and secondary aerobic filter 5 decrease sequentially. The heights of the outlets 204, 304, 404, and 505 of the primary anoxic filter, primary aerobic filter, and secondary aerobic filter decrease sequentially.

[0056] The ends of the first inlet pipe 104, the first backwash branch pipe 602, and the first vent pipe 901 are combined into one water pipe and connected to the inlet 208 of the first-stage anoxic filter; the ends of the first connecting pipe 113, the second backwash branch pipe 604, and the second vent pipe are combined into one water pipe and connected to the inlet 308 of the first-stage aerobic filter; the second inlet pipe 108, the second connecting pipe 115, the third backwash branch pipe, and the third vent pipe 908 are combined into one water pipe and connected to the inlet 408 of the second-stage anoxic filter; the ends of the third connecting pipe 117, the fourth backwash branch pipe 608, and the fourth vent pipe 910 are combined into one water pipe and connected to the inlet 508 of the second-stage aerobic filter.

[0057] Example 1

[0058] In filter media zone 801, ceramsite, characterized by its high mechanical strength, large specific surface area, easy availability, and low price, is selected as the filter media. Water flows smoothly through the ceramsite filter media, which also exhibits non-toxicity to microbial growth and reproduction and a long service life. The ceramsite particle size (d) is 3.0~5.0mm. The filter media thickness is the same in primary aerobic filter 3 and secondary aerobic filter 5; the filter media thickness is the same in primary anoxic filter 2 and secondary anoxic filter 4, and is 1.5~2.0 times that of primary aerobic filter 3 and secondary aerobic filter 5. The hydraulic loading of each filter stage is 1.20m. 3 / (m 2 ·h).

[0059] The dissolved oxygen concentration in the primary aerobic filter 3 and the secondary aerobic filter 5 is controlled at 4.0 mg / L.

[0060] In this embodiment, the installation elevation of the advanced sewage treatment system is not lower than that of the secondary treatment structure 1, and the secondary effluent water level of the secondary treatment structure 1 does not meet the required head of the system.

[0061] (a) Operating conditions

[0062] During normal operation, close the first emergency valve 122, the second emergency valve 124, and the third emergency valve 126; close the first bypass valve 110 and the second bypass valve 112; open the first inlet pump 101, the first inlet valve 102, the second inlet pump 105, the second inlet valve 106, the first connecting valve 114, the second connecting valve 116, the third connecting valve 118, and the outlet valve 128; close the backwash pump 601, the first backwash valve 603, the second backwash valve 605, the third backwash valve 607, and the fourth backwash valve 609; close the first vent valve 903, the second vent valve 906, the third vent valve 909, and the fourth vent valve 912; close the air supply valves 704 corresponding to the primary anoxic filter 2 and the secondary anoxic filter 4; and open the air supply pump 701 and the air supply valves 704 corresponding to the primary aerobic filter 3 and the secondary aerobic filter 5.

[0063] Two AO biological filter groups operate independently and simultaneously, with a water treatment capacity of Q for each group. The influent to each AO biological filter group is divided into two parts: the first influent pump 101 has an influent flow rate of 0.7Q, and the second influent pump 105 has an influent flow rate of 0.7Q.

[0064] The effluent from the secondary treatment structure 1 is divided into two parts. Part of the effluent enters the primary anoxic filter 2 through the first inlet pipe 104 for treatment, and then passes through the primary aerobic filter 3, the secondary anoxic filter 4, and the secondary aerobic filter 5 in sequence before being discharged through the effluent pipe 119. The other part enters the secondary anoxic filter 4 through the second inlet pipe 108, and then passes through the secondary aerobic filter 5 before being discharged through the effluent pipe 119.

[0065] The multi-point inlet design of the primary anoxic filter 2 and the secondary anoxic filter 4 can improve the sewage treatment capacity, better achieve the further purification of the secondary effluent, and solve the problems of low organic matter concentration in the secondary effluent leading to difficulty in treatment and high total nitrogen concentration.

[0066] When the influent COD concentration is in the range of 45.50~76.05 mg / L, this invention achieves a COD removal rate of 64.20%, and the effluent COD concentration is below 30.0 mg / L, meeting the Class IV water quality standard of the "Surface Water Environmental Quality Standard" (GB3838-2002). Regarding the influent NH4... + When the -N concentration is in the range of 3.30~10.85 mg / L, this invention provides protection against NH4+. + The removal rate of -N was 92.42%, and the effluent NH4 + -N concentration meets the Class III water quality standard of the "Surface Water Environmental Quality Standard" (GB3838-2002).

[0067] (II) Maintenance Conditions

[0068] When performing maintenance on a filter, close the valves at both ends for inlet and outlet water. Open the emergency valves upstream and downstream to temporarily divert the water into another AO biological filter group for treatment before diverting it back to the original AO biological filter group for continued treatment. This skips the filter under maintenance without affecting the operation of the system.

[0069] Taking the overhaul of a primary anoxic filter 2 as an example, shut off its front-end first inlet pump 101, first inlet valve 102, and its rear-end first connecting valve 114, and open its first vent valve 903 to drain the water before proceeding with the overhaul. At the same time, open the first emergency valve 122 to divert the effluent from the other primary anoxic filter 2 to two primary aerobic filters 3 for further treatment.

[0070] Taking the overhaul of a primary aerobic filter 3 as an example, close its front-end first connecting valve 114 and its rear-end second connecting valve 116, and open its second vent valve 906 to drain the water before proceeding with the overhaul. Simultaneously, open the first emergency valve 122 and the second emergency valve 124. The effluent from the primary anoxic filter 2 upstream of this primary aerobic filter 3 flows through the first emergency pipe 121 into another primary aerobic filter 3, and after treatment, is diverted to two secondary anoxic filters 4 for further treatment.

[0071] Taking the overhaul of a secondary aerobic filter 5 as an example, close its front-end third connecting valve, its rear-end outlet valve 128, and its corresponding air supply valve 704, and open its fourth vent valve 912 to drain the water before proceeding with the overhaul. Simultaneously, open the third emergency valve 126. The effluent from the secondary anoxic filter 4 upstream of this secondary aerobic filter 5 flows into another secondary aerobic filter 5 via the third emergency pipe, and after treatment, is discharged through the outlet pipe 119.

[0072] (III) Backwashing Operation

[0073] When backwashing a filter, similar to the maintenance process, close the valves at both ends for inlet and outlet water. Open the emergency valves upstream and downstream to temporarily divert the water into another AO biological filter group for treatment before diverting it back to the original AO biological filter group for continued treatment. This skips the filter under maintenance without affecting the system's operation.

[0074] Taking the backwashing of a secondary anoxic filter 4 as an example, the second connecting valve 116 at its front end and the third connecting valve 118 at its rear end are closed. The third backwash valve 607 and the backwash pump 601 are opened for backwashing, and the corresponding air supply valve 704 is opened to assist in backwashing. The flushing water flows out through the overflow port 407, overflow branch pipe 127, and overflow pipe 120 of the secondary anoxic filter. After flushing, the third backwash valve 607, the backwash pump 601, and the corresponding air supply valve 704 are closed, and the third vent valve 909 is opened to drain the water. At the same time as backwashing, the second emergency valve 124 and the third emergency valve 126 are opened. The effluent from the primary aerobic filter 3 at the front end of the secondary anoxic filter 4 flows into another secondary anoxic filter 4 through the second emergency pipe 123. After treatment, it is diverted to two secondary aerobic filters 5 for further treatment.

[0075] Example 2

[0076] In this embodiment, the installation elevation of the advanced wastewater treatment system is lower than that of the secondary treatment structure 1, and the secondary effluent level of the secondary treatment structure 1 meets the head requirements of the system.

[0077] During normal operation, the difference between this embodiment and Embodiment 1 is that: the first inlet pump 101, the first inlet valve 102, the second inlet pump 105, and the second inlet valve 106 are closed; the first bypass valve 110 and the second bypass valve 112 are opened. The secondary effluent from the secondary treatment structure 1 enters the primary anoxic filter 2 and the secondary anoxic filter 4 through the first bypass pipe 109 and the second bypass pipe 111, respectively, maximizing the utilization of the head of the secondary treatment structure, avoiding energy input, and reducing system energy consumption.

[0078] This invention utilizes the advantages of both biological filters and activated sludge processes to perform advanced treatment of effluent from secondary wastewater treatment plants. To further enhance the removal of ammonia nitrogen, total nitrogen, and low-concentration organic matter, it employs a multi-point influent design with primary and secondary anoxic filters. This design also improves wastewater treatment capacity and better purifies the secondary effluent, solving the problem of low organic matter concentration in the influent for advanced treatment. This invention boasts advantages such as simple process structure, low investment, low cost, convenient operation and management, and high treatment efficiency. It exhibits excellent removal effects on chemical oxygen demand (COD), total nitrogen (TN), ammonia nitrogen, and total phosphorus (TP). The effluent COD concentration meets the Class IV water quality standard of the "Surface Water Environmental Quality Standard" (GB3838-2002), and the effluent NH4+ concentration is also satisfactory. + -N concentration meets the Class III water quality standard of the "Surface Water Environmental Quality Standard" (GB3838-2002).

Claims

1. A wastewater deep treatment system for carbon removal and nitrification, characterized in that: It includes an AO biological filter group, which consists of a primary anoxic filter (2), a primary aerobic filter (3), a secondary anoxic filter (4), and a secondary aerobic filter (5) connected in sequence. The bottom of the primary anoxic filter (2) is provided with a primary anoxic filter inlet (208), and the primary anoxic filter inlet (208) is connected to a first inlet pipe (104). The first inlet pipe (104) is provided with a first inlet pump (101) and a first inlet valve (102). The bottom of the secondary anoxic filter (4) is provided with a secondary anoxic filter inlet (408), and the secondary anoxic filter inlet (408) is connected to a second inlet pipe (108). The second inlet pipe (108) is provided with a second inlet pump (105) and a second inlet valve (106). The upper side wall of the first-stage anoxic filter (2) is provided with a first-stage anoxic filter outlet (204), and the bottom of the first-stage aerobic filter (3) is provided with a first-stage aerobic filter inlet (308). A first connecting pipe (113) is provided between the first-stage anoxic filter outlet (204) and the first-stage aerobic filter inlet (308). The upper side wall of the primary aerobic filter (3) is provided with a primary aerobic filter outlet (304), and the bottom of the secondary anoxic filter (4) is provided with a secondary anoxic filter inlet (408). A second connecting pipe (115) is provided between the primary aerobic filter outlet (304) and the secondary anoxic filter inlet (408). The upper side wall of the secondary anoxic filter (4) is provided with a secondary anoxic filter outlet (404), and the bottom of the secondary aerobic filter (5) is provided with a secondary aerobic filter inlet (508). A third connecting pipe (117) is provided between the secondary anoxic filter outlet (404) and the secondary aerobic filter inlet (508). The upper side wall of the secondary aerobic filter (5) is provided with a secondary aerobic filter outlet (504), and the secondary aerobic filter outlet (504) is connected to an outlet pipe (119), and an outlet valve (128) is provided on the outlet pipe (119).

2. The wastewater deep treatment system for carbon removal and nitrification according to claim 1, characterized in that: The first water pump (101) is connected to a first bypass pipe (109) at both ends, and a first bypass valve (110) is provided on the first bypass pipe (109); the second water pump (105) is connected to a second bypass pipe (111) at both ends, and a second bypass valve (112) is provided on the second bypass pipe (111).

3. A wastewater deep treatment system for carbon removal and nitrification according to claim 1 or 2, characterized in that: The system includes two AO biological filter groups, which are connected in parallel.

4. The wastewater deep treatment system for carbon removal and nitrification according to claim 3, characterized in that: It also includes a backflushing pipe (610) and an overflow pipe (120); A backwash pump (601) is installed on the backwash pipe (610). The backwash pipe (610) is connected to a first backwash branch pipe (602), a second backwash branch pipe (604), a third backwash branch pipe (606), and a fourth backwash branch pipe (608). The first backwash branch pipe (602) is connected to the inlet (208) of the primary anoxic filter. A first backwash valve (603) is installed on the first backwash branch pipe (602). The second backwash branch pipe (604) is connected to... A second backwash valve (605) is installed on the second backwash branch pipe (604) to the inlet (308) of the first-stage aerobic filter; a third backwash valve (607) is installed on the third backwash branch pipe (606) to the inlet (408) of the second-stage anoxic filter; and a fourth backwash valve (609) is installed on the fourth backwash branch pipe (608) to the inlet (508) of the second-stage aerobic filter. The upper side wall of the first-stage anoxic filter (2) is provided with an overflow port (207) for the first-stage anoxic filter, the upper side wall of the first-stage aerobic filter (3) is provided with an overflow port (307) for the first-stage aerobic filter, the upper side wall of the second-stage anoxic filter (407) is provided with an overflow port (407) for the second-stage anoxic filter, and the upper side wall of the second-stage aerobic filter (507) is provided with an overflow port (507) for the second-stage aerobic filter. Multiple overflow branch pipes (127) are provided on the overflow pipe (120), and the overflow branch pipes (127) are connected one-to-one with the overflow port (207) of the first-stage anoxic filter, the overflow port (307) of the first-stage aerobic filter, the overflow port (407) of the second-stage anoxic filter, and the overflow port (507) of the second-stage aerobic filter.

5. A wastewater deep treatment system for carbon removal and nitrification according to claim 4, characterized in that: It also includes an air supply pipe (702), an air supply pump (701) is provided on the air supply pipe (702), and multiple air supply branch pipes (703) are provided on the air supply pipe (702). The air supply branch pipes (703) are connected one-to-one to the first-stage anoxic filter (2), the first-stage aerobic filter (3), the second-stage anoxic filter (4), and the second-stage aerobic filter (5). An air supply valve (704) is provided on the air supply branch pipe (703).

6. A wastewater deep treatment system for carbon removal and nitrification according to claim 5, characterized in that: An air flow meter (705) is installed on the air supply branch pipe (703) connected to the primary aerobic filter (3) and the secondary aerobic filter (5).

7. A wastewater deep treatment system for carbon removal and nitrification according to claim 6, characterized in that: The inlet (208) of the first-stage anoxic filter is also connected to a first vent pipe (901), and a first vent valve (903) is provided on the first vent pipe (901); the inlet (308) of the first-stage aerobic filter is also connected to a second vent pipe (904), and a second vent valve (906) is provided on the second vent pipe (904); the inlet (408) of the second-stage anoxic filter is also connected to a third vent pipe (907), and a third vent valve (909) is provided on the third vent pipe (907); the inlet (508) of the second-stage aerobic filter is also connected to a fourth vent pipe (910), and a fourth vent valve (912) is provided on the fourth vent pipe (910).

8. A wastewater deep treatment system for carbon removal and nitrification according to claim 7, characterized in that: Two first connecting valves (114) are provided on the first connecting pipe (113). A first emergency pipe (121) is provided between the first connecting pipes (113) of the two AO biological filter groups. The first emergency pipe (121) is connected between the two first connecting valves (114). A first emergency valve (122) is provided on the first emergency pipe (121). Two second connecting valves (116) are provided on the second connecting pipe (115). A second emergency pipe (123) is provided between the second connecting pipes (115) of the two AO biological filter groups. The second emergency pipe (123) is connected between the two second connecting valves (116). A second emergency valve (124) is provided on the second emergency pipe (123). Two third connecting valves (118) are provided on the third connecting pipe (117). A third emergency pipe (125) is provided between the third connecting pipes (117) of the two AO biological filter groups. The third emergency pipe (125) is connected between the two third connecting valves (118) and a third emergency valve (126) is provided on the third emergency pipe (125).

9. A wastewater deep treatment system for carbon removal and nitrification according to claim 8, characterized in that: The primary anoxic filter (2), primary aerobic filter (3), secondary anoxic filter (4), and secondary aerobic filter (5) have the same internal structure. From bottom to top, they are provided with a perforated water distribution plate (803), a pebble cushion layer (802), and a filter media area (801). The primary anoxic filter (2) and secondary anoxic filter (4) are provided with a cover plate on top. The primary aerobic filter (3) and secondary aerobic filter (5) have an open top structure.

10. A wastewater deep treatment system for carbon removal and nitrification according to claim 9, characterized in that: The heights of the first-stage anoxic filter (2), the first-stage aerobic filter (3), the second-stage anoxic filter (4), and the second-stage aerobic filter (5) decrease sequentially.

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