A sewage pretreatment tank and sewage treatment process

Abstract

The present invention relates to a sewage pretreatment tank and sewage treatment process, comprising a tank body and a grille slot arranged on the top of the tank body, the inner cavity of the tank body is divided by two partitions into a regulating area, a sand settling area and a mud storage area arranged in sequence in the horizontal direction, the grille slot is connected with a water inlet pipe and a sewage pipe, the lower end of the sewage pipe extends into the bottom of the sand settling area, and the two partitions are respectively provided with a plurality of water holes; it also includes a drainage mechanism connected with the regulating area and a mud inlet pipe connected with the mud storage area, the outlet end of the drainage mechanism is connected with a water outlet pipe, and the lower end of the mud inlet pipe extends into the bottom of the mud storage area; an aeration mechanism and a reflux mechanism are arranged in the mud storage area, and the output end of the reflux mechanism is connected with the regulating area and the sand settling area. The pretreatment tank of the present invention has a compact structure, low investment cost and good treatment effect, and can also play a role in hydrolysis and acidification, reduce subsequent biochemical load, and the internal mud storage area digests part of the sludge through micro-aeration, greatly reducing the amount of residual sludge, and preventing the release of phosphorus.

Description

Technical Field

[0001] The invention relates to a sewage pretreatment tank and a sewage treatment process, in particular to an integrated rural sewage pretreatment tank and a sewage treatment process, belonging to the technical field of sewage treatment. Background Art

[0002] The economic development level of rural areas cannot catch up with that of urban areas. In addition, due to the regional environment and sewage quality characteristics, the wastewater treatment technology cannot be applied mechanically to urban sewage. Economic, reasonable and efficient processes should be adopted according to local conditions. Therefore, the construction of new rural sewage treatment systems urgently needs an integrated treatment system with low investment and operation costs, small footprint and high treatment effect.

[0003] At present, rural sewage treatment technology is mainly based on biochemical treatment technology. Biochemical processes can effectively remove pollutants such as COD, BOD, ammonia nitrogen, and total phosphorus in wastewater. However, due to the unstable water quality and quantity of rural sewage and the large amount of debris, it is easy to cause blockage and loss of pipe networks and treatment facilities, thereby affecting the biochemical treatment effect of wastewater and increasing the operating cost of equipment. Although the pretreatment facilities of existing traditional integrated sewage treatment equipment are equipped with a regulating area, there is no grille device or sand settling area, and it cannot separate and treat the debris in the water body well. Although some centralized sewage treatment facilities will be equipped with grille devices or sand settling areas, due to civil construction, their construction costs are higher than those of integrated equipment. Summary of the invention

[0004] In view of the deficiencies in the prior art, one of the purposes of the present invention is to provide a sewage pretreatment tank with a compact structure and good treatment effect; a second purpose of the present invention is to provide a sewage treatment process.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0006] A sewage pretreatment tank comprises a tank body and a grille groove arranged on the top of the tank body, the inner cavity of the tank body is divided by two partitions into a regulating area, a grit settling area and a sludge storage area arranged in sequence in the horizontal direction, the grille groove is connected with a water inlet pipe and a sewage pipe, the lower end of the sewage pipe extends into the bottom of the grit settling area, and the two partitions are respectively provided with a plurality of water holes, the water holes are located above the lower end of the sewage pipe; it also comprises a drainage mechanism connected with the regulating area and a sludge inlet pipe connected with the sludge storage area, the outlet end of the drainage mechanism is connected with a water outlet pipe, the lower end of the sludge inlet pipe extends into the bottom of the sludge storage area; an aeration mechanism and a reflux mechanism are provided in the sludge storage area, and the output end of the reflux mechanism is connected with the regulating area and the grit settling area.

[0007] In this way, the grid trough, adjustment area, sand settling area and mud storage area are integrated into one, with a compact structure. The sewage to be treated enters the grid trough through the water inlet pipe. After removing large particles of debris, the sewage enters the sand settling area through the sewage pipe, settles and separates, and the finer particles are deposited at the bottom of the sand settling area. At the same time, the clean water in the sand settling area enters the adjustment area through the water hole to adjust the water volume and water quality. The effluent from the adjustment area can be sent to the subsequent biochemical treatment unit through the water outlet pipe for biochemical treatment; in addition, the residual sludge generated by the biochemical treatment unit can be sent to the mud storage area, and part of the sludge can be aerated and digested through the aeration mechanism to reduce the sludge volume. At the same time, the reflux mechanism can partially return the activated sludge generated in the mud storage area to the adjustment area and the sand settling area, which plays a role in hydrolysis and acidification, reduces the load of subsequent biochemical treatment, and improves the effluent water quality; in addition, the supernatant in the mud storage area can flow into the sand settling area through the water hole on the partition. The debris and sludge in the grid trough, sand settling area and mud storage area can be cleaned regularly.

[0008] The setting of the sludge storage area, on the one hand, the residual sludge from the subsequent biochemical treatment can be input into the sludge storage area through the sludge pipe, avoiding the cost increase caused by the separate sludge storage structure or sludge storage tank; on the other hand, the activated sludge produced in the sludge storage area can be conveniently returned to the sand settling area and the adjustment area, and through hydrolysis and acidification, the load of subsequent biochemical treatment can be reduced, thereby improving the treatment effect and efficiency.

[0009] Furthermore, a guide plate is provided in the grille groove, the bottom surface of the guide plate is fixed on the bottom surface of the grille groove, and one end surface of the guide plate is fixed on the side wall of the grille groove, so that a C-shaped flow channel is formed in the grille groove, and a grille is provided in the C-shaped flow channel, and the grille is located in the flow channel section between the water inlet pipe and the sewage pipe. In this way, through the action of the C-shaped flow channel and the grille, the kinetic energy of the sewage can be weakened, so that the sewage flows into the sand settling area at a stable and appropriate speed, avoiding unnecessary disturbances and improving the treatment effect; in addition, the grille can remove large-sized debris in the sewage and prevent pipe blockage.

[0010] Furthermore, the grille is inclined along the direction of water flow to facilitate cleaning of the grille.

[0011] Optionally, the angle between the grid and the horizontal plane is 60-80°, preferably 75°.

[0012] Furthermore, the inner cavity of the tank body is divided into a regulating area, a sand settling area and a mud storage area arranged in sequence by a first partition and a second partition parallel to each other, and the position of the water hole on the second partition is higher than the position of the water hole on the first partition. In this way, the supernatant in the mud storage area flows into the sand settling area through the water hole, and the supernatant in the sand settling area flows into the regulating area through the water hole, and the overall flow is unidirectional.

[0013] Optionally, the water hole is a circular hole or a rectangular hole.

[0014] Optionally, the water hole is a rectangular hole with a size of L*H=0.3*0.08mm.

[0015] Furthermore, the drainage mechanism includes a first submersible pump and a water pump outlet pipe which are connected in sequence, the first submersible pump is fixed to the bottom of the adjustment area, and the water pump outlet pipe is connected to the outlet pipe.

[0016] Furthermore, the reflux mechanism includes a second submersible pump arranged at the bottom of the mud storage area, and the output end of the second submersible pump is connected in parallel with a first reflux pipe and a second reflux pipe, the first reflux pipe extends into the adjustment area, and the lower end of the second reflux pipe extends into the bottom of the sand settling area.

[0017] Furthermore, the aeration mechanism includes an aeration inlet pipe and a perforated aeration pipe connected to the aeration inlet pipe. Through micro-aeration, part of the sludge is aerobically digested, which greatly reduces the amount of residual sludge in the biochemical stage, reduces the sludge disposal fee and thus reduces the operating cost, and prevents the residual sludge from anaerobic digestion, avoids the release of phosphorus and the generation of odor.

[0018] Furthermore, it also includes a first inspection port, a second inspection port and a third inspection port, which are respectively arranged at the top of the adjustment area, the sand settling area and the mud storage area to facilitate regular inspection of the operation of pipelines and facilities to ensure the normal operation of the pretreatment tank.

[0019] Optionally, the tank body is made of glass fiber reinforced plastics.

[0020] A sewage treatment process comprises the following steps:

[0021] The sewage to be treated is input into the sewage pretreatment tank as described above through the water inlet pipe, and the pretreated sewage is obtained at the output end of the water outlet pipe;

[0022] Performing biochemical treatment on the pretreated sewage to obtain residual sludge;

[0023] The excess sludge is introduced into the sludge storage area through the sludge inlet pipe, and activated sludge is obtained after aeration treatment;

[0024] Part of the activated sludge is returned to the adjustment area and the sand settling area through the return mechanism.

[0025] Furthermore, the biochemical treatment is AAO treatment.

[0026] Preferably, during aeration treatment, the aeration amount (DO) is 0.6-1 mg / L.

[0027] Optionally, 40-60wt% of the activated sludge is returned to the adjustment zone and the sand settling zone through a return mechanism.

[0028] The present invention integrates a grid trough, a sand settling area, a regulating area, and a mud storage area, effectively solving the problems of substandard effluent quality, blockage of rural sewage treatment facilities, high construction investment costs, and long cycles. The pretreatment tank of the present invention is equipped with a mud storage area, which avoids the cost increase caused by the single mud storage structure or mud storage tank. At the same time, an aeration mechanism is provided for micro-aeration, which can digest the residual sludge generated by the biochemical system, greatly reduce the amount of residual sludge, reduce the sludge disposal fee, and thus reduce the operating cost. Micro-aeration can also prevent the residual sludge from anaerobic digestion through micro-aeration, avoid the release of phosphorus and the generation of odor. The present invention can adjust the scale according to the characteristics of rural sewage and local conditions. It is not only convenient and quick to design, but also time-saving and labor-saving to install. It not only occupies a small area, but also saves construction investment.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The pretreatment tank of the present invention has various functional units integrated into one, with a compact structure, small footprint, low investment cost, good treatment effect, and high degree of automation. The internal sludge storage area uses micro-aeration to digest part of the sludge, greatly reducing the amount of residual sludge, reducing operating costs, and preventing the release of phosphorus.

[0031] (2) The equipment is highly integrated and modular, and can be designed for scale, enabling rapid, mass production and shortening equipment production period.

[0032] (3) The activated sludge in the sludge storage area is returned to the adjustment area and the sand settling area through the return mechanism, which plays a role in hydrolysis and acidification, converting the insoluble organic matter in the sewage into soluble organic matter, and converting the difficult-to-biodegrade organic matter into easily biodegradable organic matter, thereby improving the biodegradability of the wastewater, reducing the load of the biochemical process, and ensuring that the effluent water quality meets the standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a top view of a sewage pretreatment tank according to a first embodiment of the present invention.

[0034] Figure 2 is along Figure 1 Section view along line AA.

[0035] Figure 3 is along Figure 1 Cross-sectional view along line BB.

[0036] Figure 4 is along Figure 1 Sectional view along the CC line.

[0037] Figure 5 is along Figure 1 Sectional view along line DD.

[0038] Figure 6 is along Figure 1 Cross-sectional view along line EE.

[0039] In the figure, 1-tank body, 2-adjustment area, 3-sand settling area, 4-mud storage area, 5-first inspection port, 6-grid slot, 7-second inspection port, 8-third inspection port, 9-grid, 10-guide plate, 11-sewage pipe, 12-mud inlet pipe, 13-aeration inlet pipe, 14-drainage mechanism, 1401-first submersible pump, 1402-water pump outlet pipe, 15-water inlet pipe, 16-water outlet pipe, 17-first partition, 18-second partition, 19-water hole A, 20-water hole B, 21-first return pipe, 22-perforated aeration pipe, 23-second return pipe, 24-return mechanism, 2401-second submersible pump, 2402-main return pipe. DETAILED DESCRIPTION

[0040] The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. For the convenience of description, if the words "upper", "lower", "left" and "right" appear in the following, they only indicate that the upper, lower, left and right directions are consistent with the drawings themselves, and do not limit the structure.

[0041] See also Figure 1-6 A sewage pretreatment tank comprises a tank body 1 and a grille slot 6 arranged on the top of the tank body, the inner cavity of the tank body is divided by two partitions into a regulating area 2, a grit settling area 3 and a mud storage area 4 arranged in sequence in the horizontal direction, the grille slot 6 is connected with a water inlet pipe 15 and a sewage pipe 11, the lower end of the sewage pipe 11 extends into the bottom of the grit settling area 3, and the two partitions are respectively provided with a plurality of water holes, the water holes are located above the lower end of the sewage pipe 11; it also comprises a drainage mechanism 14 connected with the regulating area 2 and a mud inlet pipe 12 connected with the mud storage area 4, the outlet end of the drainage mechanism 14 is connected with a water outlet pipe 16, the lower end of the mud inlet pipe 12 extends into the bottom of the mud storage area 4; an aeration mechanism and a reflux mechanism are arranged in the mud storage area 4, and the output end of the reflux mechanism is connected with the regulating area 2 and the grit settling area 3.

[0042] A guide plate 10 is provided in the grille groove 6, the bottom surface of the guide plate 10 is fixed on the bottom surface of the grille groove 6, and one end surface of the guide plate 10 is fixed on the side wall of the grille groove 6, so that a C-shaped flow channel is formed in the grille groove 6, and a grille 9 is provided in the C-shaped flow channel, and the grille 9 is located in the flow channel section between the water inlet pipe 15 and the sewage pipe 11.

[0043] The lower end of the sewage pipe 11 is connected to a water distribution pipe 1101, which is horizontally arranged to form an inverted T-shaped structure. In this way, the sewage flows into the sand settling area 3 in a horizontal direction, which can effectively reduce the adverse disturbance caused by the inflowing sewage to the bottom layer of the sand settling area 3.

[0044] The grid 9 is inclined along the water flow direction.

[0045] The inner cavity of the tank body is divided into a regulating area 2, a sand settling area 3 and a mud storage area 4 arranged in sequence by a first partition 17 and a second partition 18 which are parallel to each other. The water hole A19 on the second partition 18 is located at a higher position than the water hole B20 on the first partition 17.

[0046] The drainage mechanism 14 includes a first submersible pump 1401 and a water pump outlet pipe 1402 which are connected in sequence, wherein the first submersible pump 1401 is fixed to the bottom of the regulating area 2, and the water pump outlet pipe is connected to the outlet pipe 16. Optionally, a water pump outlet pipe is arranged inside the regulating area, and the water pump outlet pipe is connected to the outlet pipe through a first inspection port on the upper part of the tank body.

[0047] The reflux mechanism 24 includes a second submersible pump 2401 arranged at the bottom of the mud storage area. The output end of the second submersible pump 2401 is connected to a main reflux pipe 2402. The main reflux pipe 2402 is connected in parallel with a first reflux pipe 21 and a second reflux pipe 23. The first reflux pipe 21 extends into the adjustment area 2, and the lower end of the second reflux pipe 23 extends into the bottom of the sand settling area 3.

[0048] The aeration mechanism includes an aeration inlet pipe 13 and a plurality of perforated aeration pipes 22 connected to the aeration inlet pipe, and the aeration inlet pipe 13 is connected to a blower disposed outside the tank body. The plurality of perforated aeration pipes 22 are evenly distributed at the bottom of the mud storage area.

[0049] It also includes a first inspection port 5, a second inspection port 7 and a third inspection port 8, which are respectively arranged at the top of the regulating area 2, the sand settling area 3 and the mud storage area 4. The first inspection port is connected to the water outlet pipe on one side and to the grille slot on the other side, and is located above the regulating area; the second inspection port is connected to the other side of the grille slot and is located above the sand settling area; the third inspection port is connected to the other side of the second inspection port and is located above the mud storage area.

[0050] During operation, sewage enters the grille slot 6 from the water inlet pipe 15, flows through the grille 9 through the guide plate 10 in the grille slot 6, and the grille 9 can intercept the coarser particles and debris in the sewage to avoid clogging the pipeline and subsequent treatment facilities. After passing through the grille 9, the sewage enters the grit settling area 3 through the sewage pipe 12. The grit settling area 3 can remove the finer particles and impurities in the sewage, effectively reduce the SS of the sewage, improve the water quality, and enhance the subsequent treatment capacity. The sewage treated in the grit settling area 3 overflows from the water hole on the first partition 17 into the regulating area 2. The regulating area 2 can adjust the water volume and water quality of the sewage to ensure that the subsequent treatment facilities are not affected by the peak flow or concentration changes of the sewage. The effluent of the regulating area 2 is connected to the outlet pipe 16 through the water pump outlet pipe 1402 and enters the subsequent biochemical treatment process. The excess sludge obtained by the biochemical treatment process enters the sludge storage area 4 through the sludge pipe 12. The sludge storage area 4 is provided with an aeration air inlet pipe 13 and a perforated aeration pipe 21. The excess sludge is prevented from anaerobic digestion through micro-aeration, and the release of phosphorus and the generation of odor are avoided. The supernatant in the sludge storage area 4 flows into the grit settling area 3 through the water holes on the second partition 18. The debris, sludge, etc. in the grille 9, the grit settling area 3, and the sludge storage area 4 need to be cleaned regularly, and the operation of the pipelines and facilities should be regularly checked through the inspection port to ensure the normal operation of the system.

[0051] The applicant tried the above pretreatment tank in a rural centralized sewage treatment project of 1000t / d, with influent COD350mg / L, BOD150mg / L, SS100mg / L, TN 40mg / L, and the biodegradability of the wastewater was good. The sewage was first passed into the above sewage pretreatment tank (2*500t / d), and then connected to the biochemical treatment process. The wastewater entered the 2*500t / d pretreatment tank through the inlet pipe, and after being treated through the grid-sand settling area-regulation area, it entered the AAO reaction area. The residual sludge in the AAO reaction area was discharged into the sludge storage area in the pretreatment tank through the sludge pipe. The project operated stably, and the effluent quality of the biochemical treatment process section was good. The removal rates of COD, SS, and TN were 88.5%, 91.0%, and 70.5%, respectively, reaching the Class A standard of the Pollutant Discharge Standard for Urban Sewage Treatment Plants (GB18918-2002).

[0052] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

Claims

1. A sewage pretreatment tank, characterized in that: The invention comprises a tank body (1) and a grille groove (6) arranged on the top of the tank body, wherein the inner cavity of the tank body (1) is divided into a regulating area (2), a sand settling area (3) and a mud storage area (4) arranged in sequence in the horizontal direction by two partitions, the grille groove (6) is connected to a water inlet pipe (15) and a sewage pipe (11), the lower end of the sewage pipe (11) extends into the bottom of the sand settling area (3), and the two partitions are respectively provided with a plurality of water holes, wherein the water holes are located above the lower end of the sewage pipe (11); and the invention also comprises a drainage mechanism (14) connected to the regulating area (2) and a drainage mechanism (14) connected to the mud storage area. (4) is connected to a mud inlet pipe (12), the outlet end of the drainage mechanism (14) is connected to a water outlet pipe (16), and the lower end of the mud inlet pipe (12) extends into the bottom of the mud storage area (4); an aeration mechanism and a reflux mechanism are provided in the mud storage area (4), and the output end of the reflux mechanism is connected to the regulating area (2) and the sand settling area (3); a guide plate (10) is provided in the grille groove (6), the bottom surface of the guide plate (10) is fixed to the bottom surface of the grille groove (6), and one end surface of the guide plate (10) is fixed to the side wall of the grille groove (6), so that the grille groove (6) is provided with a guide plate (10), and the bottom surface of the guide plate (10) is fixed to the bottom surface of the grille groove (6), and the end surface of one side of the guide plate (10) is fixed to the side wall of the grille groove (6), so that the grille groove (6) is provided with a guide plate (10), and the bottom surface of the guide plate (10) is fixed to the side wall of the grille groove (6), so that the grille groove (6) is provided with a guide plate (10), and the guide plate (10) is fixed to the side wall of the grille groove (6), so that the grille groove (6) is provided with a guide plate (10), and the guide plate (10) is fixed to the bottom surface of the grille groove (6), and the guide plate (10) is fixed to the side wall of the grille groove (6), so that the grille groove (6) is provided with a guide plate (10 ... A C-shaped flow channel is formed in the grating groove (6), wherein a grating (9) is provided in the C-shaped flow channel, and the grating (9) is located in the flow channel section between the water inlet pipe (15) and the sewage pipe (11); the inner cavity of the tank body (1) is divided into a regulating area (2), a sand settling area (3) and a mud storage area (4) arranged in sequence by a first partition plate (17) and a second partition plate (18) which are parallel to each other, and the position of the water hole on the second partition plate (18) is higher than the position of the water hole on the first partition plate (17); the drainage mechanism (14) comprises a first submersible pump (1401) which is connected in sequence ) and a water pump outlet pipe (1402), the first submersible pump (1401) is fixed at the bottom of the regulating area (2), the water pump outlet pipe (1402) is connected to the outlet pipe (16); the reflux mechanism (24) comprises a second submersible pump (2401) arranged at the bottom of the mud storage area (4), the output end of the second submersible pump (2401) is connected in parallel with a first reflux pipe (21) and a second reflux pipe (23), the first reflux pipe (21) extends into the regulating area (2), and the lower end of the second reflux pipe (23) extends into the sand settling area (3).

2. The sewage pretreatment tank according to claim 1, characterized in that: The grille (9) is inclined along the direction of water flow.

3. The sewage pretreatment tank according to claim 1, characterized in that: The aeration mechanism comprises an aeration inlet pipe (13) and a perforated aeration pipe (22) connected to the aeration inlet pipe.

4. The sewage pretreatment tank according to any one of claims 1 to 3, characterized in that: It also comprises a first inspection port (5), a second inspection port (7) and a third inspection port (8), wherein the first inspection port (5), the second inspection port (7) and the third inspection port (8) are respectively arranged at the top of the adjustment area (2), the sand settling area (3) and the mud storage area (4).

5. A sewage treatment process, characterized in that: The steps include: Inputting the sewage to be treated into the sewage pretreatment tank according to any one of claims 1 to 4 through the water inlet pipe (15), and obtaining the pretreated sewage at the output end of the water outlet pipe (16); Performing biochemical treatment on the pretreated sewage to obtain residual sludge; The excess sludge is fed into the sludge storage area (4) through the sludge inlet pipe (12) and aerated to obtain activated sludge; A portion of the activated sludge is returned to the adjustment area (2) and the sand settling area (3) through the return mechanism.

6. The sewage treatment process according to claim 5, characterized in that: The biochemical treatment is AAO treatment.

Images