Multifunctional secondary sedimentation tank

Abstract

The invention discloses a multifunctional secondary sedimentation tank which comprises a water distribution channel, a water outlet channel and a plurality of secondary sedimentation tanks, the water inlet pipe controls water inflow through a water inlet gate; the sludge inlet pipe is arranged between the plurality of secondary sedimentation tanks and the sludge pipe, and the sludge inlet amount of the plurality of secondary sedimentation tanks is controlled through a sludge inlet valve; the first water outlet pipe is arranged between the plurality of secondary sedimentation tanks and the water outlet channel and controls water outlet through a water outlet valve A; the second water outlet pipe is arranged between the plurality of secondary sedimentation tanks and the supernatant discharge pipe, and water outlet is controlled through a water outlet valve B; the sludge return pipe is arranged between the sludge hoppers at the starting ends of the plurality of secondary sedimentation tanks and the biological treatment system and is used for controlling the sludge flow through a sludge discharge valve A; the residual sludge pipe is arranged between the middle sludge hoppers of the secondary sedimentation tanks and the sludge treatment system, controls the sludge flow through a sludge discharge valve D, and is provided with a residual sludge pump at the same time; the starting end sludge hopper is communicated with the sludge discharge pipe through a sludge discharge valve B, the middle sludge hopper is communicated with the sludge discharge pipe through a sludge discharge valve C, and meanwhile, a sludge discharge pump is arranged.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection, in particular to a water treatment technology, in particular to a multifunctional secondary sedimentation tank. Background Art

[0002] The sedimentation tank after biological treatment is called the secondary or final sedimentation tank. The secondary sedimentation tank's function is to separate mud and water, clarify the mixed liquor, concentrate the sludge, and return the separated sludge to the biological treatment stage. Its effectiveness directly affects the effluent quality and the concentration of the returned sludge.

[0003] To ensure that the effluent meets the standards, most existing sedimentation tanks occupy a larger area, resulting in higher project investment; to ensure the amount of return sludge, most existing secondary sedimentation tanks adopt a higher sludge return ratio, resulting in higher operating costs.

[0004] With the advancement of the "carbon peak" and "carbon neutrality" policies, sewage treatment systems also need technical measures to save energy and reduce consumption. How to transform the existing secondary sedimentation tank process, improve the sludge sedimentation performance, improve the treatment effect and operation stability of the biochemical tank, while increasing the return sludge concentration, reducing the sludge return volume, and saving energy and reducing consumption is of great significance. Summary of the Invention

[0005] The present invention aims to provide a multifunctional secondary sedimentation tank, which can effectively solve the problems existing in the prior art.

[0006] According to one aspect of the present invention, a multifunctional secondary sedimentation tank is provided, comprising: a water distribution channel, a water outlet channel, and a plurality of secondary sedimentation tanks arranged between the water distribution channel and the water outlet channel; a water inlet pipe, arranged between the plurality of secondary sedimentation tanks and the water distribution channel, and controlling water inlet through a water inlet gate; a mud inlet pipe, arranged between the plurality of secondary sedimentation tanks and the sludge pipe, and controlling the mud inlet amount of the plurality of secondary sedimentation tanks through a mud inlet valve; a first water outlet pipe, arranged between the plurality of secondary sedimentation tanks and the water outlet channel, and controlling water outlet through a water outlet valve A; a second water outlet pipe, arranged between the plurality of secondary sedimentation tanks and the water outlet channel, and controlling water outlet through a water outlet valve A; a third water outlet pipe, arranged between the plurality of secondary sedimentation tanks and the water outlet channel, and controlling water outlet through a water outlet valve A; a fourth water outlet pipe, arranged between the plurality of secondary sedimentation tanks and the water outlet channel, and controlling water outlet through a water outlet valve A; a fifth ... distribution channel, and controlling water inlet through a water outlet valve The second outlet pipe is arranged between the several secondary sedimentation tanks and the supernatant discharge pipe, and the outlet water is controlled by the outlet valve B; the sludge return pipe is arranged between the starting sludge hoppers of the several secondary sedimentation tanks and the biological treatment system, and the sludge flow is controlled by the sludge discharge valve A; the residual sludge pipe is arranged between the middle sludge hoppers of the several secondary sedimentation tanks and the sludge treatment system, and the sludge flow is controlled by the sludge discharge valve D, and a residual sludge pump is also arranged; the starting sludge hopper is connected to the sludge discharge pipe through the sludge discharge valve B, and the middle sludge hopper is connected to the sludge discharge pipe through the sludge discharge valve C.

[0007] Preferably, the plurality of secondary sedimentation tanks include a first secondary sedimentation tank, a second secondary sedimentation tank, and a third secondary sedimentation tank.

[0008] Preferably, the water inlet gate includes a first water inlet gate, a second water inlet gate, and a third water inlet gate.

[0009] Preferably, the mud inlet valve includes a first mud inlet valve, a second mud inlet valve, and a third mud inlet valve.

[0010] Preferably, the mud discharge valve A includes the first mud discharge valve A, the second mud discharge valve A, and the third mud discharge valve A; the mud discharge valve B includes the first mud discharge valve B, the second mud discharge valve B, and the third mud discharge valve B; the mud discharge valve C includes the first mud discharge valve C, the second mud discharge valve C, and the third mud discharge valve C; the mud discharge valve D includes the first mud discharge valve D, the second mud discharge valve D, and the third mud discharge valve D.

[0011] Preferably, the water outlet valve A includes a first water outlet valve A, a second water outlet valve A, and a third water outlet valve A; the water outlet valve B includes a first water outlet valve B, a second water outlet valve B, and a third water outlet valve B.

[0012] Preferably, a first sludge valve is provided at the intersection of the primary sludge pipe and the sludge inlet pipe; a second sludge valve is provided at the intersection of other sludge pipes and the sludge inlet pipe; a third sludge valve is provided at the intersection of the residual sludge pipe and the sludge inlet pipe; a fourth sludge valve is provided at the intersection of the residual sludge pipe and the sludge discharge pipe; and a fifth sludge valve is provided at the intersection of the sludge discharge pipe and the sludge treatment system.

[0013] According to another aspect of the present invention, a method for treating sewage using the above-mentioned secondary sedimentation tank is provided, wherein the first water inlet gate, the second water inlet gate, the third water inlet gate and the fourth sludge valve are opened, the sludge inlet valve and the sludge discharge pipe are closed, and the sludge discharge pipe is closed by closing the sludge discharge valves B and C, the third sludge valve, the fifth sludge valve and the sludge discharge pump, so that all the sewage enters the first secondary sedimentation tank, the second secondary sedimentation tank and the third secondary sedimentation tank for treatment, and the residual sludge pump is opened; the first sludge discharge valve A, the second sludge discharge valve A and the third sludge discharge valve A are opened, and the first sludge discharge valve B, the third sludge valve and the fifth sludge valve are closed. The second sludge discharge valve B and the third sludge discharge valve B connect the return sludge in the starting sludge hopper to the biological treatment system; open the first sludge discharge valve D, the second sludge discharge valve D and the third sludge discharge valve D, close the first sludge discharge valve C, the second sludge discharge valve C, and the third sludge discharge valve C, and discharge the remaining sludge in the middle sludge hopper into the sludge treatment system; open the first water outlet valve A, the second water outlet valve A, and the third water outlet valve A, close the first water outlet valve B, the second water outlet valve B, and the third water outlet valve B, and discharge the effluent from the first secondary sedimentation tank, the second secondary sedimentation tank, and the third secondary sedimentation tank into the subsequent treatment process.

[0014] According to another aspect of the present invention, a method for treating sewage using the above-mentioned secondary sedimentation tank is provided, wherein the first water inlet gate, the second water inlet gate and the residual sludge pump are opened, and the third water inlet gate is closed, so that all the sewage enters the first secondary sedimentation tank and the second secondary sedimentation tank for treatment; the first mud discharge valve A and the second mud discharge valve A are opened, the first mud discharge valve B and the second mud discharge valve B are closed, and the return sludge in the starting mud hopper is connected to the biological treatment system; the first mud discharge valve D, the second mud discharge valve D and the fourth mud valve are opened, and the first mud discharge valve C and the second mud discharge valve C are closed. , discharge the sludge in the middle sludge hopper into the sludge treatment system; open the first sludge valve and the third sludge inlet valve, close the second sludge valve and the third sludge valve, as well as the first sludge inlet valve and the second sludge inlet valve, and let all the primary sludge enter the third secondary sedimentation tank; by opening the sludge pump, the third sludge valve B, the third sludge valve C and the fifth sludge valve, closing the third sludge valve A and the third sludge valve D, discharge the sludge into the sludge treatment system; open the third water outlet valve B, close the third water outlet valve A, and transport the supernatant to the designated carbon source addition point.

[0015] According to another aspect of the present invention, a method for treating sewage using the above-mentioned secondary sedimentation tank is provided, wherein the first water inlet gate, the second water inlet gate and the residual sludge pump are opened, and the third water inlet gate is closed, so that all the sewage enters the first secondary sedimentation tank and the second secondary sedimentation tank for treatment; the first mud discharge valve A and the second mud discharge valve A are opened, the first mud discharge valve B and the second mud discharge valve B are closed, and the return sludge in the starting mud hopper is connected to the biological treatment system; the first mud discharge valve D, the second mud discharge valve D and the third mud valve are opened, and the first mud discharge valve C and the second mud discharge valve C are closed. Mud valve C and the fourth sludge valve discharge the remaining sludge in the middle sludge hopper into the third secondary sedimentation tank; open the third sludge inlet valve, the first sludge valve and the second sludge valve, close the first sludge inlet valve and the second sludge inlet valve, and let all the sludge enter the third secondary sedimentation tank. By opening the sludge discharge pump, the third sludge discharge valve B, the third sludge discharge valve C and the fifth sludge valve, closing the third sludge discharge valve A and the third sludge discharge valve D, the sludge is discharged into the sludge treatment system; open the third water outlet valve B, close the third water outlet valve A, and transport the supernatant to the designated treatment unit.

[0016] According to the technical solution provided by the present invention, based on the principle of sedimentation, sludge settling performance improves the closer it is to the water inlet. Therefore, by installing multiple sludge hoppers within the secondary sedimentation tank, located at the beginning and middle of the tank, sludge with different settling performance can be screened. Sludge with poor settling performance near the end of the sedimentation tank enters the middle sludge hopper and is removed as residual sludge. Sludge with good settling performance enters the sludge hopper at the beginning of the secondary sedimentation tank and is returned to the biochemical treatment system. After a period of operation and commissioning, the settling performance of the sludge in the entire system is improved, improving the treatment effect and operational stability of the biochemical tank, increasing the concentration of the returned sludge, reducing the amount of sludge returned, and reducing energy consumption. While improving the sedimentation effect, the demand for secondary sedimentation tanks can be reduced. Idle secondary sedimentation tanks can be equipped with pipelines, valves, water pumps, instruments, and electronic control systems to serve as sludge hydrolysis tanks and sludge thickening tanks.

[0017] The present invention is a transformation based on the traditional secondary sedimentation tank, and the overall system is simple with low investment and operating costs. All functions of the original secondary sedimentation tank can be retained; sludge can be screened, the sludge properties of the biological pool can be improved, the treatment effect and operational stability of the biochemical pool can be improved, the return sludge concentration can be increased, the sludge return volume can be reduced, and energy conservation and consumption reduction can be achieved; the operation mode of the idle secondary sedimentation tank can be changed to sludge hydrolysis, sludge concentration and other modes according to the water quality conditions. The technical solution described in the present invention can realize space-time dual-dimensional regulation, combine the physical structure of the secondary sedimentation tank (valve group distribution) with the real-time control algorithm, break through the traditional single control dimension, and realize the synergistic efficiency of "spatial screening + timing optimization". Through the deep integration of structural innovation and control, it has achieved a leap from "extensive operation" to "precision energy efficiency management" in the field of sewage treatment, and has significant technological advancement and engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0019] Explanation of the figure markings: For ease of description and understanding, in the figures of this specification, for systems or devices with multiple similar components (such as multiple mud discharge valves), they are marked in the form of "basic identifier + superscript number" (for example, "mud discharge valve B1", "mud discharge valve B2", "mud discharge valve B3"). The superscript numbers "1", "2", "3", etc. here correspond to the ordinal numbers such as "first", "second", and "third" described in the main text of the specification and the claims. For example, the "mud discharge valve A1" in the figure refers to the "first mud discharge valve A" in the main text of the specification and the claims, and the "mud discharge valve A2" refers to the "second mud discharge valve A", and so on. Those skilled in the art should understand that such superscript numbers are only used to indicate the order and the correspondence with the main text of the specification, and do not imply any special limitations on structure, function or position, unless otherwise expressly stated.

[0020] Figure 1 is a schematic diagram of a system layout according to an embodiment of the present invention;

[0021] Figure 2 This is a logic diagram of the operating conditions of a traditional secondary sedimentation tank provided according to an embodiment of the present invention;

[0022] Figure 3 This is a logic diagram of the operating conditions of the sludge hydrolysis mode provided according to an embodiment of the present invention;

[0023] Figure 4 This is a logic diagram of the operating conditions of the sludge concentration mode provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0025] system

[0026] This embodiment involves a multifunctional secondary sedimentation tank, comprising an inlet system, a sludge inlet system, a secondary sedimentation tank, an outlet system, a return sludge system, a residual sludge system, a sludge discharge system, and a supernatant discharge system. By switching between different operating modes, sludge screening, hydrolysis, concentration, and other related treatment functions are achieved. By rationally controlling the opening and closing of each system, the sludge treatment process is optimized, improving the treatment efficiency and economic efficiency of the secondary sedimentation tank.

[0027] The water inlet system, consisting of a main inlet pipe, distribution channels, inlet gates 1, 2, and 3, and supporting piping, is responsible for connecting upstream sewage to each secondary sedimentation tank. The system utilizes multiple inlets to precisely control sewage flow and direction.

[0028] The sludge inlet system consists of multiple sludge valves, sludge flow meters, and sludge concentration meters. Its main function is to collect various types of sludge in the plant and send them to each secondary sedimentation tank.

[0029] The secondary sedimentation tank consists of three independent tanks, each equipped with a sludge hopper, scraper, and sludge and slag discharge equipment. The sludge hoppers are located at the beginning and middle of the secondary sedimentation tank and are used to screen sludge with different settling properties. The scraper is used to scrape the sludge settled at the bottom of the tank into the sludge hopper.

[0030] The return sludge system includes the discharge pipes and return sludge piping system at the front end of each secondary sedimentation tank. Sludge flows into the biochemical treatment system through the return pipes to maintain the sludge concentration in the biological tank, improve sludge settling properties, and enhance the biological treatment effect.

[0031] The excess sludge system is responsible for collecting and discharging poorly sedimentable sludge from the secondary sedimentation tank. This system includes a discharge pipe from the central sludge hopper, a sludge discharge valve, an excess sludge flow meter and concentration meter, a sludge valve, and an excess sludge pump. The discharged sludge can be concentrated in other secondary sedimentation tanks or directly sent to the sludge treatment system.

[0032] The outlet water system consists of the outlet pipes, outlet valves and main outlet pipelines of each secondary sedimentation tank. Its main function is to discharge clean water from the secondary sedimentation tank to the subsequent treatment unit to ensure that the treated water quality meets the discharge standards.

[0033] The sludge discharge system includes sludge discharge pipes, sludge discharge valves, sludge discharge pumps and other equipment in the sludge hoppers before and after each secondary sedimentation tank, which is responsible for discharging the settled sludge out of the secondary sedimentation tank through pipes.

[0034] The supernatant discharge system includes a supernatant discharge pipe, a supernatant pump and a flow meter, which is used to send the clean water into the designated treatment system.

[0035] like Figure 1As shown, according to one embodiment of the present invention, a multifunctional secondary sedimentation tank is provided, comprising: a water distribution channel, a water outlet channel, and a plurality of secondary sedimentation tanks arranged between the water distribution channel and the water outlet channel; a water inlet pipe, arranged between the plurality of secondary sedimentation tanks and the water distribution channel, and controlling water inlet through a water inlet gate; a mud inlet pipe, arranged between the plurality of secondary sedimentation tanks and the mud pipe, and controlling mud inlet amount of the plurality of secondary sedimentation tanks through a mud inlet valve; a first water outlet pipe, arranged between the plurality of secondary sedimentation tanks and the water outlet channel, and controlling water outlet through a water outlet valve A; a second ... distribution channel, and controlling water inlet through a water outlet valve The water pipe is installed between the several secondary sedimentation tanks and the supernatant discharge pipe, with the water outlet controlled by the outlet valve B. The sludge return pipe is installed between the initial sludge hoppers of the several secondary sedimentation tanks and the biological treatment system, with the sludge flow rate controlled by the sludge discharge valve A. The residual sludge pipe is installed between the middle sludge hoppers of the several secondary sedimentation tanks and the sludge treatment system, with the sludge flow rate controlled by the sludge discharge valve D, and a residual sludge pump is also provided. The initial sludge hopper is connected to the sludge discharge pipe via the sludge discharge valve B, and the middle sludge hopper is connected to the sludge discharge pipe via the sludge discharge valve C, and a sludge discharge pump is also provided. The several secondary sedimentation tanks include the first secondary sedimentation tank, the second secondary sedimentation tank, and the third secondary sedimentation tank. The water inlet gates include the first water inlet gate, the second water inlet gate, and the third water inlet gate. The mud inlet valves include the first mud inlet valve, the second mud inlet valve, and the third mud inlet valve. Mud discharge valve A includes the first, second, and third mud discharge valves A; mud discharge valve B includes the first, second, and third mud discharge valves B; mud discharge valve C includes the first, second, and third mud discharge valves C; and mud discharge valve D includes the first, second, and third mud discharge valves D. Outlet valve A includes the first, second, and third outlet valves A; and outlet valve B includes the first, second, and third outlet valves B. A first sludge valve is installed at the intersection of the primary sludge pipe and the mud inlet pipe; a second sludge valve is installed at the intersection of other sludge pipes and the mud inlet pipe; a third sludge valve is installed at the intersection of the excess sludge pipe and the mud inlet pipe; a fourth sludge valve is installed at the intersection of the excess sludge pipe and the mud discharge pipe; and a fifth sludge valve is installed at the intersection of the mud discharge pipe and the sludge treatment system.

[0036] In the above embodiments, the first mud discharge valve A is shown as mud discharge valve A1, and the first sludge valve is shown as sludge valve 1, and the same applies to other examples.

[0037] Working conditions and operating modes

[0038] Working condition 1: See Figure 2 , sludge screening mode.

[0039] Open: water inlet gates 1, 2, 3, water outlet valves A1, A2, A3, sludge valve 4, sludge discharge valves A1, A2, A3, D1, D2, D3, and residual sludge pump.

[0040] Close: mud inlet valves 1, 2, 3, sludge valves 1, 2, 3, 5, outlet valves B1, B2, B3, mud discharge valves B1, B2, B3, mud discharge valves C1, C2, C3, and mud discharge pump.

[0041] All sewage enters three secondary sedimentation tanks for treatment, and the effluent is directly discharged into the subsequent treatment process. The return sludge is all taken from the starting sludge hopper, and the remaining sludge is all taken from the middle sludge hopper.

[0042] According to the sedimentation principle, the closer the sludge is to the water inlet, the better its sedimentation performance. Therefore, the sludge with better sedimentation performance and higher sludge concentration will pass through the front sludge hopper and the return system and return to the biochemical treatment system. The sludge with poor sedimentation performance will be sent to the sludge treatment system through the middle sludge hopper and the residual sludge system for discharge.

[0043] like Figure 2 As shown, according to another embodiment of the present invention, a method for treating sewage using the above-mentioned secondary sedimentation tank is provided, the first water inlet gate, the second water inlet gate, the third water inlet gate and the fourth sludge valve are opened, the sludge inlet valve and the sludge discharge pipe are closed, the sludge discharge pipe is closed by closing the sludge discharge valves B and C, the third sludge valve, the fifth sludge valve and the sludge discharge pump, and all the sewage enters the first secondary sedimentation tank, the second secondary sedimentation tank and the third secondary sedimentation tank for treatment, and the residual sludge pump is opened; the first sludge discharge valve A, the second sludge discharge valve A, the third sludge discharge valve A are opened, the first sludge discharge valve B, the third sludge valve C and the fifth sludge valve C are closed. The second sludge discharge valve B and the third sludge discharge valve B connect the return sludge in the starting sludge hopper to the biological treatment system; open the first sludge discharge valve D, the second sludge discharge valve D and the third sludge discharge valve D, close the first sludge discharge valve C, the second sludge discharge valve C, and the third sludge discharge valve C, and discharge the remaining sludge in the middle sludge hopper into the sludge treatment system; open the first water outlet valve A, the second water outlet valve A, and the third water outlet valve A, close the first water outlet valve B, the second water outlet valve B, and the third water outlet valve B, and discharge the effluent from the first secondary sedimentation tank, the second secondary sedimentation tank, and the third secondary sedimentation tank into the subsequent treatment process.

[0044] Working condition 2: See Figure 3 , sludge hydrolysis mode.

[0045] After a period of operation, the sludge properties of the entire biochemical system are improved, the sludge settling properties are enhanced, the secondary sedimentation tank load can be appropriately increased, and the number of secondary sedimentation tanks in operation can be reduced. Replacing idle secondary sedimentation tanks with sludge hydrolysis tanks can fully utilize the carbon source in the primary sludge, eliminating the need for additional structures, saving on purchased carbon sources, and reducing operating costs.

[0046] Open: water inlet gates 1 and 2, water outlet valves A1, A2, B3, sludge discharge valves A1, A2, D1, D2, B3, C3, sludge valves 1, 4, 5, sludge inlet valve 3, residual sludge pump, sludge discharge pump;

[0047] Close: water inlet gate 3, mud inlet valves 1 and 2, sludge valves 2 and 3, water outlet valves B1, B2, A3, mud discharge valves B1, B2, C1, C2, A3, D3.

[0048] The sewage enters the secondary sedimentation tanks 1 and 2 for treatment, and the effluent is directly discharged into the subsequent treatment process. The primary sludge is connected to the secondary sedimentation tank 3 through the sludge inlet pipe. At this time, the function of the secondary sedimentation tank 3 is a sludge hydrolysis tank.

[0049] The sludge from the hydrolysis tank is mixed with the residual sludge from the secondary sedimentation tanks 1 and 2 and discharged into the sludge treatment system; the supernatant from the hydrolysis tank is rich in VFA and is pumped to the designated carbon source addition point.

[0050] The operation mode of secondary sedimentation tanks 1 and 2 is the same as that of working condition 1. The sludge with better sedimentation and higher sludge concentration is returned to the biological treatment system, and the sludge with poor sedimentation is discharged.

[0051] like Figure 3 As shown, according to another embodiment of the present invention, a method for treating sewage using the above-mentioned secondary sedimentation tank is provided, wherein the first water inlet gate, the second water inlet gate and the residual sludge pump are opened, and the third water inlet gate is closed, so that all the sewage enters the first secondary sedimentation tank and the second secondary sedimentation tank for treatment; the first mud discharge valve A and the second mud discharge valve A are opened, the first mud discharge valve B and the second mud discharge valve B are closed, and the return sludge in the starting mud hopper is connected to the biological treatment system; the first mud discharge valve D, the second mud discharge valve D and the fourth mud valve are opened, and the first mud discharge valve C and the second mud discharge valve C are closed. Mud valve C, discharges the sludge in the middle sludge hopper into the sludge treatment system; opens the first sludge valve and the third sludge inlet valve, closes the second sludge valve and the third sludge valve, as well as the first sludge inlet valve and the second sludge inlet valve, and allows all the primary sludge to enter the third secondary sedimentation tank. By opening the sludge discharge pump, the third sludge discharge valve B and the third sludge discharge valve C and the fifth sludge valve, closing the third sludge discharge valve A and the third sludge discharge valve D, the sludge is discharged into the sludge treatment system; opens the third water outlet valve B, closes the third water outlet valve A, and transports the supernatant to the designated treatment unit.

[0052] Working condition 3: See Figure 4 , sludge concentration mode.

[0053] Sewage treatment systems often have high moisture content in various sludge types, including excess sludge, chemical sludge, and digested sludge. Consequently, large sludge volumes are generated, leading to large-scale sludge treatment and high operating costs. In these cases, idle secondary sedimentation tanks can be converted to sludge concentration mode to fully utilize their effective capacity, reduce sludge moisture content, minimize sludge volume, and save operating costs.

[0054] Open: water inlet gates 1 and 2, water outlet valves A1, A2, B3, sludge discharge valves A1, A2, D1, D2, B3, C3, sludge valves 1, 2, 3, 5, sludge inlet valve 3, residual sludge pump, sludge discharge pump;

[0055] Close: water inlet gate 3, mud inlet valves 1 and 2, sludge valve 4, water outlet valves B1, B2, A3, mud discharge valves B1, B2, C1, C2, A3, D3.

[0056] Wastewater enters secondary sedimentation tanks 1 and 2 for treatment, with the effluent directly discharged into subsequent treatment processes. Primary sludge, excess sludge, and other sludge are fed through a sludge inlet pipe into secondary sedimentation tank 3, which now functions as a sludge thickener. The sludge from the thickener is mixed with the excess sludge from secondary sedimentation tanks 1 and 2 and discharged into the sludge treatment system. The supernatant from the hydrolysis tank is pumped to designated phosphorus removal or other treatment units. Secondary sedimentation tanks 1 and 2 operate in the same manner as in Condition 1. Sludge with better settling properties and higher sludge concentration is returned to the biochemical treatment system, while less settling sludge is discharged.

[0057] like Figure 4 As shown, according to another embodiment of the present invention, a method for treating sewage using the above-mentioned secondary sedimentation tank is provided, wherein the first water inlet gate, the second water inlet gate and the residual sludge pump are opened, and the third water inlet gate is closed, so that all the sewage enters the first secondary sedimentation tank and the second secondary sedimentation tank for treatment; the first mud discharge valve A and the second mud discharge valve A are opened, and the first mud discharge valve B and the second mud discharge valve B are closed, and the return sludge in the starting mud hopper is connected to the biological treatment system; the first mud discharge valve D, the second mud discharge valve D and the third mud valve are opened, and the first mud discharge valve C and the second mud discharge valve C are closed. The mud valve C and the fourth sludge valve discharge the remaining sludge in the middle sludge hopper into the third secondary sedimentation tank; open the third mud inlet valve, the first sludge valve and the second sludge valve, close the first mud inlet valve and the second mud inlet valve, and let all types of sludge enter the third secondary sedimentation tank; open the mud discharge pump, the third mud discharge valve B, the third mud discharge valve C and the fifth sludge valve, close the third mud discharge valve A and the third mud discharge valve D, and discharge the sludge into the sludge treatment system; open the third water outlet valve B, close the third water outlet valve A, and transport the supernatant to the designated treatment unit.

[0058] Working condition 4: other modes.

[0059] Based on the aforementioned basic operating modes, multiple combinations can be implemented based on the water plant's specific circumstances. The present invention utilizes a multifunctional secondary sedimentation tank, combined with the ability to switch between different operating modes, to achieve efficient sludge treatment and resource utilization. Precise control of each system not only improves sludge treatment efficiency but also achieves energy conservation and emission reduction, reducing operating costs. The system's intelligent and automated management ensures efficient operation of the water treatment plant.

[0060] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A multifunctional secondary sedimentation tank, characterized in that: include: a water distribution channel, a water outlet channel, and a plurality of secondary sedimentation tanks disposed between the water distribution channel and the water outlet channel; A water inlet pipe is provided between the plurality of secondary sedimentation tanks and the water distribution channel, and controls water inlet through a water inlet gate; A mud inlet pipe is provided between the plurality of secondary sedimentation tanks and the sludge pipe, and controls the amount of mud inlet to the plurality of secondary sedimentation tanks through a mud inlet valve; A first outlet pipe is provided between the plurality of secondary sedimentation tanks and the outlet channel, and controls the outlet of the water through an outlet valve A; The second outlet pipe is provided between the plurality of secondary sedimentation tanks and the supernatant discharge pipe, and the outlet is controlled by an outlet valve B; The sludge return pipe is arranged between the starting sludge hoppers of the several secondary sedimentation tanks and the biological treatment system, and the sludge flow rate is controlled by the sludge discharge valve A; The residual sludge pipe is arranged between the middle sludge hoppers of the several secondary sedimentation tanks and the sludge treatment system, and the sludge flow rate is controlled by the sludge discharge valve D, and a residual sludge pump is also provided; The starting sludge hopper is connected to the sludge discharge pipe through a sludge discharge valve B, and the middle sludge hopper is connected to the sludge discharge pipe through a sludge discharge valve C. A sludge discharge pump is also provided.

2. The secondary sedimentation tank according to claim 1, characterized in that The several secondary sedimentation tanks include the first secondary sedimentation tank, the second secondary sedimentation tank, and the third secondary sedimentation tank.

3. The secondary sedimentation tank according to claim 2, characterized in that The water inlet gate includes a first water inlet gate, a second water inlet gate, and a third water inlet gate.

4. The secondary sedimentation tank according to claim 3, characterized in that The mud inlet valve includes a first mud inlet valve, a second mud inlet valve, and a third mud inlet valve.

5. The secondary sedimentation tank according to claim 4, characterized in that: The mud discharge valve A includes the first mud discharge valve A, the second mud discharge valve A, and the third mud discharge valve A; the mud discharge valve B includes the first mud discharge valve B, the second mud discharge valve B, and the third mud discharge valve B; the mud discharge valve C includes the first mud discharge valve C, the second mud discharge valve C, and the third mud discharge valve C; the mud discharge valve D includes the first mud discharge valve D, the second mud discharge valve D, and the third mud discharge valve D.

6. The secondary sedimentation tank according to claim 5, characterized in that: The water outlet valve A includes a first water outlet valve A, a second water outlet valve A, and a third water outlet valve A; the water outlet valve B includes a first water outlet valve B, a second water outlet valve B, and a third water outlet valve B.

7. The secondary sedimentation tank according to claim 6, characterized in that: A first sludge valve is set at the intersection of the primary sludge pipe and the sludge inlet pipe; a second sludge valve is set at the intersection of other sludge pipes and the sludge inlet pipe; a third sludge valve is set at the intersection of the residual sludge pipe and the sludge inlet pipe; a fourth sludge valve is set at the intersection of the residual sludge pipe and the sludge discharge pipe; and a fifth sludge valve is set at the intersection of the sludge discharge pipe and the sludge treatment system.

8. A method for treating sewage using the secondary sedimentation tank according to claim 7, characterized in that: Open the first water inlet gate, the second water inlet gate, the third water inlet gate, and the fourth sludge valve, close the sludge inlet valve and the sludge discharge pipe, close the sludge discharge valves B and C, the fifth sludge valve, and the sludge discharge pump to close the sludge discharge pipe, and let all the sewage enter the first secondary sedimentation tank, the second secondary sedimentation tank, and the third secondary sedimentation tank for treatment, and start the excess sludge pump; Open the first mud discharge valve A, the second mud discharge valve A, and the third mud discharge valve A, close the first mud discharge valve B, the second mud discharge valve B, and the third mud discharge valve B, and connect the return sludge in the starting sludge hopper to the biological treatment system; Open the first sludge discharge valve D, the second sludge discharge valve D and the third sludge valve, close the first sludge discharge valve C, the second sludge discharge valve C and the third sludge discharge valve C, and discharge the remaining sludge in the middle sludge hopper into the sludge treatment system; Open the first outlet valve A, the second outlet valve A, and the third outlet valve A, close the first outlet valve B, the second outlet valve B, and the third outlet valve B, and discharge the effluent from the first secondary sedimentation tank, the second secondary sedimentation tank, and the third secondary sedimentation tank into a subsequent treatment process.

9. A method for treating sewage using the secondary sedimentation tank according to claim 8, characterized in that: Opening the first water inlet gate, the second water inlet gate and the excess sludge pump, closing the third water inlet gate, and allowing all sewage to enter the first secondary sedimentation tank and the second secondary sedimentation tank for treatment; Open the first sludge discharge valve A and the second sludge discharge valve A, close the first sludge discharge valve B and the second sludge discharge valve B, and connect the return sludge in the starting sludge hopper to the biological treatment system; Open the first sludge discharge valve D, the second sludge discharge valve D and the fourth sludge valve, close the first sludge discharge valve C and the second sludge discharge valve C, and discharge the sludge in the middle sludge hopper into the sludge treatment system; Open the first sludge valve and the third sludge inlet valve, close the second sludge valve and the third sludge valve, as well as the first sludge inlet valve and the second sludge inlet valve, and discharge all the primary sludge into the third secondary sedimentation tank; open the sludge discharge pump, the third sludge discharge valve B, the third sludge discharge valve C, and the fifth sludge valve, and close the third sludge discharge valve A and the third sludge discharge valve D, and discharge the sludge into the sludge treatment system; The third water outlet valve B is opened, and the third water outlet valve A is closed to transport the supernatant to the designated treatment unit.

10. A method for treating sewage using the secondary sedimentation tank according to claim 9, characterized in that: Opening the first water inlet gate, the second water inlet gate and the excess sludge pump, closing the third water inlet gate, and allowing all sewage to enter the first secondary sedimentation tank and the second secondary sedimentation tank for treatment; Open the first sludge discharge valve A and the second sludge discharge valve A, close the first sludge discharge valve B and the second sludge discharge valve B, and connect the return sludge in the starting sludge hopper to the biological treatment system; Open the first sludge discharge valve D, the second sludge discharge valve D and the third sludge valve, close the first sludge discharge valve C, the second sludge discharge valve C and the fourth sludge valve, and discharge the remaining sludge in the middle sludge hopper into the third secondary sedimentation tank; Open the third sludge inlet valve, the first sludge valve, and the second sludge valve, close the first sludge inlet valve and the second sludge inlet valve, and allow all the sludge to enter the third secondary sedimentation tank; open the sludge discharge pump, the third sludge discharge valve B, the third sludge discharge valve C, and the fifth sludge valve, and close the third sludge discharge valve A and the third sludge discharge valve D to discharge the sludge into the sludge treatment system; The third water outlet valve B is opened, and the third water outlet valve A is closed to transport the supernatant to the designated treatment unit.

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