CN212609808U

CN212609808U - Sewage treatment system

Info

Publication number: CN212609808U
Application number: CN202021520623.9U
Authority: CN
Inventors: 刘伟岩; 魏彬; 汪力; 张平; 马文瑾; 王启镔; 郭毅; 王亿宝; 郝二成
Original assignee: Beijing Shuihui Intelligent Technology Co ltd; Beijing Enterprises Water China Investment Co Ltd
Current assignee: Beijing Shuihui Intelligent Technology Co ltd; Beijing Enterprises Water China Investment Co Ltd
Priority date: 2020-07-28
Filing date: 2020-07-28
Publication date: 2021-02-26
Anticipated expiration: 2030-07-28

Abstract

The utility model provides a sewage treatment system, which comprises an aerobic tank with a mechanical stirring device and an air blower arranged outside the aerobic tank. The air blower is communicated with the aerobic tank through an air main pipe, an air main pipe and an air branch pipe, and the air branch pipe is provided with a valve; the bottom of the aerobic tank is provided with an aerator which is arranged on the air branch pipe. And a dissolved oxygen instrument and an ammonia nitrogen instrument are arranged in the aerobic tank, a central controller is arranged outside the tank, the central controller is connected with the dissolved oxygen instrument, the ammonia nitrogen instrument and the blower, and the aeration quantity of the blower is adjusted according to the ammonia nitrogen real-time value and the dissolved oxygen real-time value. The dissolved oxygen concentration and the ammonia nitrogen concentration of all parts in water in the sewage treatment tank are almost the same, local dissolved oxygen is avoided being too high, waste of carbon source caused by endogenous respiration is reduced as much as possible, the proportion of the carbon source for nitrogen and phosphorus removal is improved, the effect of biological nitrogen and phosphorus removal is improved, and the adding amount of the carbon source and the phosphorus removal agent is reduced. Meanwhile, the aeration energy consumption is also reduced.

Description

Sewage treatment system

Technical Field

The utility model relates to a sewage treatment technical field especially relates to a sewage treatment system.

Background

The existing aeration control technologies comprise an accurate aeration technology, a model control technology based on an activated sludge reaction kinetic model and the like. The method adopted by the accurate aeration technology mainly carries out feedforward and feedback control according to the parameters of the quality and the quantity of the inlet water, the parameters of the online dissolved oxygen of the biological pond and the like, and has larger hysteresis in the control of the aeration quantity, and the phenomena of over-aeration or under-aeration, which are caused by the nonlinear characteristic of the aeration quantity and the impact of the quality and the quantity of the inlet water, are not ideal in the aeration control. The aeration control method based on the activated sludge reaction kinetic model needs more input parameters than an accurate aeration technology, needs parameters such as water quality and water quantity and online dissolved oxygen parameters, needs parameters such as online nitrate nitrogen, sludge concentration, volatile sludge concentration and water temperature, and utilizes a large amount of real-time data to calculate the aeration quantity needed by the current system, the theoretical basis of the control method is mature, but in practical application, because too much data needs to be provided and too many real-time instruments are adopted, on one hand, the instruments cannot support the detection frequency needed by calculation, on the other hand, the fault of a single instrument often brings butterfly effect, the deviation of the whole calculation result is caused, when the water quality and water quantity of inlet water have large impact, the control stability is particularly difficult to guarantee, and therefore, the method cannot realize aeration according to the ammonia nitrogen condition.

The problem that the maximum on-demand aeration cannot be realized by the existing method is that the control technology and the process tank type are not combined together by the existing aeration control technology, and the aeration control with effluent ammonia nitrogen as a target value is difficult to realize.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model aims at providing a sewage treatment system to solve the problem that can't realize aeration as required among the prior art.

Based on the purpose, the utility model provides a sewage treatment system, which comprises an aerobic tank and an air blower, wherein a mechanical stirring device is arranged in the aerobic tank, the air blower is arranged outside the aerobic tank and is communicated with the aerobic tank through an air main pipe, an air main pipe and an air branch pipe, and a valve is arranged on the air branch pipe; an aerator is arranged at the bottom of the aerobic tank and is arranged on the air branch pipe; the inside of the aerobic tank is also provided with a dissolved oxygen instrument and an ammonia nitrogen instrument, the outside of the aerobic tank is provided with a central controller, and the central controller is respectively connected with the dissolved oxygen instrument, the ammonia nitrogen instrument and the blower.

Optionally, a group of U-shaped guide walls respectively located at two ends of the aerobic tank are further arranged in the aerobic tank.

Optionally, the number of the aerobic tanks is one or more; when the number of the aerobic tanks is multiple, a water passing opening is arranged between the adjacent aerobic tanks.

Optionally, the central controller is connected to the dissolved oxygen meter, the ammonia nitrogen meter and the blower through signal lines respectively.

Optionally, the mechanical stirring device is one or more of a flow impeller or a vertical stirrer.

Optionally, when the mechanical stirring device works, the air volume of the blower can be reduced to a minimum value or the blower is turned off.

Optionally, the sewage treatment system further comprises an anaerobic tank and an anoxic tank, wherein one side of the anoxic tank is connected with the anaerobic tank, and the other side of the anoxic tank is connected with the aerobic tank.

From the above, can see, the utility model provides a sewage treatment system, through setting up the aerator in good oxygen bottom of the pool portion, set up mechanical stirring device simultaneously in good oxygen pond, in order to guarantee that mixed liquid when aeration is at good oxygen pond circulation flow and reach the effect of intensive mixing, intake to good oxygen pond carries out the dilution fast and mixes, in order to make the water in good oxygen pond reach the complete mixing, the aquatic dissolved oxygen concentration is almost the same everywhere, avoid appearing the too high condition of local dissolved oxygen, the operating stability of the sewage treatment system of technology and automatic control coupling has been strengthened, the problem of aeration inequality and aeration control lag has been solved. The aerobic tank is controlled by low dissolved oxygen, so that not only is the aeration energy consumption reduced, but also more importantly, conditions can be created for synchronous nitrification and denitrification, the denitrification rate of an aerobic zone is improved, and the cost of an external carbon source is reduced; on the other hand, the concentration of nitrate nitrogen in effluent of the aerobic tank is reduced, so that the concentration of nitrate nitrogen in return sludge outside the secondary sedimentation tank is also reduced and returns to the anaerobic zone, the influence of nitrate nitrogen on anaerobic phosphorus release is weakened, phosphorus accumulating bacteria are facilitated to absorb small-molecular organic matters to promote phosphorus release, the biological phosphorus removal efficiency is improved, and the cost of a phosphorus removal agent is saved.

Drawings

In order to more clearly illustrate one or more embodiments or prior art solutions of the present specification, the drawings that are needed in the description of the embodiments or prior art will be briefly described below, and it is obvious that the drawings in the following description are only one or more embodiments of the present specification, and that other drawings may be obtained by those skilled in the art without inventive effort from these drawings.

FIG. 1 is a schematic view of the structure of an aerobic tank in a sewage treatment system provided in the present specification;

FIG. 2 is a schematic view of the sewage treatment system provided in the present specification;

FIG. 3 is a schematic diagram of the arrangement of the air branch pipes in the aerobic tank provided by the present specification;

FIG. 4 is a schematic diagram of the logic control based on real-time ammonia nitrogen values provided herein;

FIG. 5 is a schematic diagram of the logic control provided herein based on real-time dissolved oxygen values;

Detailed Description

For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.

It is to be noted that unless otherwise defined, technical or scientific terms used in one or more embodiments of the present specification should have the ordinary meaning as understood by those of ordinary skill in the art to which this disclosure belongs. The use of "first," "second," and similar terms in one or more embodiments of the specification is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

At present, in the process of treating sewage by adopting an activated sludge method, aeration is an important link in the sewage treatment process, dissolved oxygen is provided for water through aeration, the requirement of the life activity of microorganisms is maintained, and reducing pollutants such as COD (chemical oxygen demand), ammonia nitrogen and the like are removed. With the improvement of the national sewage treatment discharge standard, the standards of total nitrogen, ammonia nitrogen, total phosphorus and COD in the effluent are strict. The amount of aeration has important influence on the standards of all indexes. If the ammonia nitrogen and even COD can not reach the standard due to insufficient aeration, the removal effect of total nitrogen and total phosphorus can be poor due to excessive aeration, the adding amount of chemical agents such as carbon sources and phosphorus removal agents is increased, the operation cost is increased, meanwhile, the pollution of the agent production link is aggravated, and the power consumption of the system is higher when the aeration is excessive. Therefore, in order to achieve the purpose that all indexes reach the standard and simultaneously reduce the operating medicine consumption and the power consumption, the method for controlling the aeration quantity according to the requirement is significant.

According to the microbial ecological principle, in the aeration link of an activated sludge system, the strain for removing COD is heterotrophic bacteria, the strain for removing ammonia nitrogen is autotrophic bacteria, the two strains are obviously different in population quantity and reaction rate, the heterotrophic bacteria population density is far greater than that of the autotrophic bacteria, and the reaction rate is far greater than that of the autotrophic bacteria, so that the COD which is easy to degrade reaches the standard when the ammonia nitrogen reaches the standard in the aeration link. According to the principle, the limiting factor of the aeration link is the residual ammonia nitrogen concentration of the aeration tank, and when the ammonia nitrogen achieves the standard, the aeration amount can be considered to be enough, so that the required residual ammonia nitrogen concentration is the required aeration amount.

The conventional aeration tank, such as a typical AAO process, an aerobic tank (O section) of the conventional aeration tank is generally a plug flow type reaction tank, the ammonia nitrogen concentration of the reaction tank is continuously changed along the process, the requirement on aeration quantity is also continuously changed, along with the change of the quality and quantity of inlet water, the point of reaching the standard of the ammonia nitrogen is also continuously changed along the process, so that the plug flow type reaction tank needs to measure the dissolved oxygen and the ammonia nitrogen at multiple points according to the requirement for aeration, a large number of instruments and complex control logics are needed, great difficulty exists in realization, and many aeration quantity control technologies or methods based on the plug flow type biological tank show weak impact resistance when the quality and quantity of the inlet water fluctuate and often fail to control.

Therefore, the main problems in the existing sewage treatment technology are as follows:

(1) the operation is unstable: the water quality and quantity of the inlet water are changed continuously, the required aeration quantity is different and is reflected on the dissolved oxygen, namely the front end dissolved oxygen is possibly lower or even insufficient, the rear end dissolved oxygen is possibly higher or even the over-aeration condition occurs. After overexposure occurs, the problems of loose sludge, small flocs and the like can be caused.

(2) The energy consumption and the medicine consumption are higher: the prior art is difficult to realize aeration according to needs, and the aeration energy consumption is wasted when excessive aeration is carried out, so that the energy consumption is higher. Excessive aeration can cause the endogenous respiration of microorganisms to be aggravated, waste carbon sources, increase the consumption of nitrogen and phosphorus removal agents and cause secondary pollution of agent production.

(3) The control accuracy is low: because the ammonia nitrogen value of the effluent cannot be accurately controlled, the dissolved oxygen is used as a main control target, the ammonia nitrogen value is too low or too high, the control precision is low, and the ammonia nitrogen value is controlled in a lower range to ensure the ammonia nitrogen value to reach the standard, so that excessive aeration is caused.

(4) Control hysteresis: the method adopted by the accurate aeration technology is mainly based on the parameters of the quality and the quantity of the inlet water, because the biological tank has hydraulic retention time of several to dozens of hours, the online dissolved oxygen parameters of the biological tank and the like to carry out feedforward and feedback control, the control of the aeration quantity has larger hysteresis, the nonlinear characteristic of the aeration quantity and the impact of the quality and the quantity of the inlet water often cause the unsatisfactory aeration control, and the phenomena of excessive aeration or insufficient aeration occur.

In order to solve the technical problem, this specification provides a sewage treatment pond, this sewage treatment pond is including the inside good oxygen pond that is provided with mechanical stirring device and set up the air-blower in good oxygen pond outside, the air-blower passes through the air main pipe, air main pipe and air branch pipe and good oxygen pond intercommunication, be provided with the valve on the control branch pipe, the bottom in good oxygen pond is provided with the aerator, the aerator sets up on air branch pipe, the inside in good oxygen pond still is provided with the dissolved oxygen appearance, ammonia nitrogen appearance, good oxygen pond outside is provided with central controller, central controller respectively with the dissolved oxygen appearance, ammonia nitrogen appearance and air-blower link to each other.

When the sewage treatment system is subjected to aeration control, monitoring whether the real-time ammonia nitrogen value in the aerobic tank is in a first threshold range or not under one condition; and when the real-time ammonia nitrogen value in the aerobic tank exceeds the first threshold range, adjusting the air volume of the air blower so as to enable the real-time ammonia nitrogen value in the aerobic tank to reach the first threshold range.

When the sewage treatment system is subjected to aeration control, monitoring whether the real-time dissolved oxygen value in the aerobic tank is in a second threshold range or not under one condition; and when the real-time dissolved oxygen value in the aerobic tank exceeds the second threshold range, adjusting the air volume of the air blower so as to enable the real-time dissolved oxygen value in the aerobic tank to reach the second threshold range.

Therefore, the sewage treatment system that this specification provided, through set up the aerator in good oxygen bottom of the pool, set up mechanical stirring device in good oxygen pond simultaneously, in order to guarantee that the mixed liquid circulates in good oxygen pond and intensive mixing when the aeration, carry out the fast dilution to the influent water of good oxygen pond and mix, so that the water in good oxygen pond reaches the complete mixing, the aquatic dissolved oxygen concentration is almost the same everywhere, avoid appearing the too high condition of local dissolved oxygen, the operation stability of the sewage treatment system of technology and automatic control coupling has been strengthened, the problem that the aeration is inhomogeneous and aeration control lags has been solved. The aerobic tank is controlled by low dissolved oxygen, so that not only is the aeration energy consumption reduced, but also more importantly, conditions can be created for synchronous nitrification and denitrification, the denitrification rate of an aerobic zone is improved, and the cost of an external carbon source is reduced; on the other hand, the concentration of nitrate nitrogen in effluent of the aerobic tank is reduced, so that the concentration of nitrate nitrogen in return sludge outside the secondary sedimentation tank is also reduced and returns to the anaerobic zone, the influence of nitrate nitrogen on anaerobic phosphorus release is weakened, phosphorus accumulating bacteria are facilitated to absorb small-molecular organic matters to promote phosphorus release, the biological phosphorus removal efficiency is improved, and the cost of a phosphorus removal agent is saved.

The sewage treatment system that this specification provided mainly possesses following advantage:

(1) the operation is stable: the stable operation of the ammonia nitrogen in the effluent near the target value can be realized, the proper aeration amount is realized, and the control precision is greatly improved.

(2) And (3) controlling in time: in the completely mixed aerobic tank, on the basis of one of three regulation and control methods of a real-time ammonia nitrogen value, a real-time dissolved oxygen value and the sharing of the real-time ammonia nitrogen value and the real-time dissolved oxygen value in the aerobic tank, the aeration quantity can be controlled in time, and the problems of uneven aeration and lagged aeration control are solved.

(3) Energy consumption is saved: in the completely mixed pool, the dissolved oxygen is controlled at a reasonable level, the condition of overhigh local dissolved oxygen is avoided, the aeration efficiency is higher, and the aeration energy consumption can be saved.

(4) The medicine consumption is saved: because aeration rate control is more reasonable, prevent excessive aeration, reduced on the one hand in the interior, the external reflux mixed liquid dissolved oxygen smugglies the influence to oxygen deficiency pond and anaerobism pond secretly, on the other hand has prevented that excessive aeration from resulting in the endogenous breathing of activated sludge to the waste of carbon source, has helped improving the carbon source and has used for the proportion of nitrogen and phosphorus removal, improves the effect of biological nitrogen and phosphorus removal, reduces the input volume of carbon source and dephosphorization medicament.

(5) Reaction diversity: the aeration quantity control method is suitable for the sewage treatment system with the process and the automatic control coupling, the aeration quantity is reduced as far as possible when the ammonia nitrogen reaches the standard, the dissolved oxygen in the aerobic tank can be controlled at a lower level, and the synchronous or short-range nitrification and denitrification can be easily triggered under the condition of low dissolved oxygen, so that the requirement of the system on a carbon source is further reduced, and the biological denitrification capacity is improved.

The sewage treatment tank provided by the specification is described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic view of the structure of an aerobic tank in a sewage treatment system provided in the present specification; as shown in fig. 1, a mechanical stirring device 11 is arranged inside the aerobic tank 1, an air blower 12 is arranged outside the aerobic tank 1, the air blower 12 is communicated with the aerobic tank 1 through an air main pipe 13, an air main pipe 131 and an air branch pipe 14, and the air branch pipe 14 is provided with a first valve 141; the mechanical stirring device 11 can promote the sewage to circularly flow in the aerobic tank 1; the aerobic tank provided with the mechanical stirring device 11 can ensure that the sludge is not settled under the condition of not starting aeration, and the mixing multiple of raw water entering the aerobic tank is generally more than 20 times; the blower 12 is provided with frequency conversion control, the frequency can be flexibly adjusted to adjust the blowing amount, when sewage is treated, the blower 12 can convey outside air to the air main pipe 13, the air main pipe 13 conveys the air to the air main pipe 131, then the air main pipe 131 conveys the air to the air branch pipe 14, and the air branch pipe 14 conveys the air to the aerobic tank 1, so that the aeration of the sewage in the aerobic tank 1 is realized.

The bottom of the aerobic tank 1 is provided with an aerator 15, the aerator 15 is arranged on an air branch pipe 14, the interior of the aerobic tank 1 is also provided with a dissolved oxygen instrument 16 and an ammonia nitrogen instrument 17, the exterior of the aerobic tank 1 is also provided with a central controller 18, and the central controller 18 is respectively connected with the dissolved oxygen instrument 16, the ammonia nitrogen instrument 17 and the blower 12. The aerator 15 receives the air transmitted by the air branch pipe 14 to realize aeration of the sewage in the aerobic tank 1. The data of the blower 12, the dissolved oxygen instrument 16 and the ammonia nitrogen instrument 17 are respectively transmitted to the central controller 18, and a user obtains the data through the central controller 18, regulates and controls the aeration rate of the blowing rate of the blower 12 based on the data, controls the dissolved oxygen in the aerobic tank 1, improves the aeration efficiency and reduces the aeration energy consumption.

FIG. 3 is a schematic diagram of the arrangement of the air branch pipes in the aerobic tank provided by the present specification; as shown in fig. 2, in practical application, the main pipe center of the air branch pipe 14 is higher than the liquid level by more than 1.0m, and after the air branch pipe 14 penetrates through the side wall of the aerobic tank 1 along the water flow direction, one of the branch pipes is turned downwards and is communicated with an aerator 15 positioned in the aerobic tank 1; a first thin pipe is led out from the upper end of the vertical pipe of the air branch pipe 14 in the aerobic tank 1 and is connected with a first transverse pipe, the diameter of the first transverse pipe is 15-20mm, a second valve 142 is arranged on the first transverse pipe, and the second valve 142 is used for discharging condensed water in an air pipeline and closing a water drain valve in time.

In practical applications, as shown in fig. 1, a partition wall 19 is further disposed in the aerobic tank 1 along the water flow direction, and a first U-shaped guide wall 101 and a second U-shaped guide wall 102 are further disposed at two ends of the partition wall 19 in the aerobic tank 1. By arranging the partition wall 19, the first U-shaped guide wall 101 and the second U-shaped guide wall 102 in the aerobic tank 1, sewage entering the aerobic tank 1 can flow in a desired water flow direction, and the sewage enters the aerobic tank 1, flows from the first U-shaped guide wall 101 to the second U-shaped guide wall 102 in the water flow direction, then flows reversely along the second U-shaped guide wall 102, and reaches the first U-shaped guide wall 101. The first U-shaped guide wall 101 and the second U-shaped guide wall 102 can prevent sewage in the aerobic tank 1 from colliding to the side wall of the aerobic tank and promote the sewage to complete the circular flow in the aerobic tank 1.

In one case, the aerobic tank 1 may not be provided with a partition wall, and the aerobic tank 1 is provided with a first U-shaped guide wall 101 and a second U-shaped guide wall 102 respectively located at two ends of the aerobic tank 1. The first U-shaped guide wall 101 and the second U-shaped guide wall 102 can prevent sewage in the aerobic tank 1 from colliding to the side wall of the aerobic tank and promote the sewage to complete the circular flow in the aerobic tank 1.

In some possible embodiments, in one case, the number of the mechanical stirring devices 11 is even, the partition wall 19 is arranged centrally in the aerobic tank 1, and the mechanical stirring devices 11 are arranged evenly on both sides of the partition wall 19. The even number of mechanical stirring devices 11 are arranged in the aerobic tank 1, and the even number of mechanical stirring devices 11 are uniformly arranged on two sides of the partition wall 19 arranged in the middle, so that the sludge can be prevented from settling under the condition that the first valve 141 is not opened in the aerobic tank 1, the circulating flow of sewage in the aerobic tank 1 can be promoted, the inflow water in the aerobic tank 1 is quickly diluted and mixed, the dissolved oxygen concentration of the sewage is almost the same, the condition that the local dissolved oxygen is too high is avoided, the running stability of the aerobic tank 1 is enhanced, and the problems of uneven aeration and lag in aeration control are solved. For example, in practical applications, 2 mechanical stirring devices or 4 mechanical stirring devices may be provided, and the like, and the present invention is not limited specifically.

In one case, the number of the mechanical stirring devices 11 is odd, and the mechanical stirring devices 11 are uniformly arranged in the aerobic tank 1. For example, in practical applications, 3 mechanical stirring devices or 5 mechanical stirring devices may be provided, and the like, and the present invention is not limited to this.

In some possible embodiments, the number of the aerators 15 is even, the number of the aerators 15 is the same as the number of the air branch pipes 14, the partition wall 19 is centrally disposed in the aerobic tank 1, and the aerators 15 are uniformly disposed at both sides of the partition wall 19. The even number of the aerators 15 are arranged in the aerobic tank 1, and the even number of the aerators 15 are uniformly arranged on two sides of the partition wall 19 arranged in the acute angle, so that the sewage in the aerobic tank 1 can be fully aerated, the dissolved oxygen concentration of each part of the sewage is almost the same, the condition of overhigh local dissolved oxygen is avoided, and the operation stability of the aerobic tank 1 is enhanced. In practical applications, the number of the aerators 15 arranged in the aerobic tank 1 and the number of the adopted air branch pipes 14 are different according to the size of the aerobic tank 1, and the arrangement can be different according to practical situations, and is not limited specifically. For example, 6 aerators and air manifolds, 8 aerators and air manifolds, and the like may be provided, and the number is not particularly limited.

In one case, the number of the aerators 15 is odd, the number of the aerators 15 is the same as the number of the air branch pipes 14, and the aerators 15 are uniformly arranged in the aerobic tank 1. In practical applications, the number of the aerators 15 arranged in the aerobic tank 1 and the number of the adopted air branch pipes 14 are different according to the size of the aerobic tank 1, and the arrangement can be different according to practical situations, and is not limited specifically. For example, 5 aerators and air manifolds, 7 aerators and air manifolds, and the like may be provided, and the number is not particularly limited.

In some possible embodiments, the number of the aerobic tanks 1 is one or more; when the number of the aerobic tanks 1 is multiple, a water passing opening is arranged between the adjacent aerobic tanks 1. When a plurality of aerobic tanks are arranged, an ammonia nitrogen instrument and a dissolved oxygen instrument are arranged in each aerobic tank. The ammonia nitrogen value in each aerobic tank corresponds to different control ranges, and each aerobic tank corresponds to a respective dissolved oxygen target value; when a plurality of aerobic tanks are arranged, the sewage can be fully aerated.

In some possible embodiments, the central controller 18 is connected to the dissolved oxygen meter 16, the ammonia nitrogen meter 17 and the blower 12 through signal lines, respectively.

In some possible embodiments, the mechanical stirring device 11 is one or more of a flow impeller or a vertical stirrer. Different types of mechanical stirring devices can be selected according to the tank type, and if the aerobic tank 1 is a rectangular tank type, a flow pusher can be adopted; if the aerobic tank 1 is a square tank, a vertical stirrer can be adopted. When the mechanical stirring device 11 works, the air volume of the blower 12 can be reduced to the minimum value or the blower 12 can be closed in a short time; prevent the sludge from sinking, realize the state of completely mixing the sewage and the sludge in the aerobic tank and solve the problems of uneven aeration and lagged aeration control.

As shown in fig. 1, the aerobic tank 1 is further provided with a first water inlet 103 and a water outlet 104, the first water inlet 103 is disposed on one side wall of the aerobic tank 1 perpendicular to the water flow direction, and the water outlet 104 is disposed on the other side wall of the aerobic tank 1 perpendicular to the water flow direction.

FIG. 2 is a schematic view of the sewage treatment system provided in the present specification; as shown in fig. 2, the sewage treatment tank further comprises an anaerobic tank 2 and an anoxic tank 3, wherein one side of the anoxic tank 3 is connected with the anaerobic tank 2, and the other side is connected with the aerobic tank 1. The lateral wall of the anoxic pond 3 is provided with a third water inlet 31, the lateral wall of the anaerobic pond 2 is provided with a second water inlet 21, sewage enters the anaerobic pond 2 from the second water inlet 21 on the lateral wall of the anaerobic pond 2, enters the anoxic pond 3 from the third water inlet 31 on the lateral wall of the anoxic pond 3 after being treated by the anaerobic pond 2, enters the aerobic pond 1 from the first water inlet 103 on the lateral wall of the aerobic pond 1 after being treated by the anoxic pond 3, and is reserved from a water outlet 104 on the other lateral wall of the aerobic pond 1 after being treated by the aerobic pond 1. The sludge-water mixed liquor at the tail end of the aerobic tank flows back to the anoxic tank 3 through the inner return pipe 6, and the sludge precipitated in the secondary sedimentation tank flows back the outer return pipe 7 to the front end of the anaerobic tank.

It should be noted that the aerobic tank type, mixing and aeration control method provided in the present specification is applicable to all treatment processes with aerobic sections for the aerobic link in the activated sludge process for sewage treatment, and fig. 2 illustrates the conventional AAO process as an example, but is not limited to the application to AAO and its variant processes, and the method can also be applied to the aerobic tanks of multi-stage AO process, Bardenpho, oxidation ditch, etc. and the aerobic period of the batch SBR process, and is also within the scope of the present invention.

FIG. 4 is a schematic diagram of the logic control based on real-time ammonia nitrogen value provided in the present specification, and FIG. 5 is a schematic diagram of the logic control based on the dissolved oxygen on-line value provided in the present specification; as shown in fig. 4 and 5, the present specification also provides an aeration control method of a sewage treatment system, the method comprising: monitoring the ammonia nitrogen value in the aerobic tank, and judging whether the real-time ammonia nitrogen value in the aerobic tank exceeds a first threshold range; if the real-time ammonia nitrogen value in the aerobic tank is judged to be higher than the first threshold range, increasing the aeration rate of the blower; if the real-time ammonia nitrogen value in the aerobic tank is judged to be lower than the first threshold range, reducing the aeration rate of the blower; or the like, or, alternatively,

monitoring the real-time dissolved oxygen value in the aerobic tank, and judging whether the real-time dissolved oxygen value in the aerobic tank exceeds a second threshold range; if the real-time dissolved oxygen value in the aerobic tank is judged to be higher than the second threshold range, reducing the aeration rate of the blower; and if the real-time dissolved oxygen value in the aerobic tank is judged to be lower than the second threshold range, increasing the aeration rate of the blower.

In practical application, the main purpose of aeration is to remove COD and ammonia nitrogen in sewage by using activated sludge, and according to the microbial ecological principle, microorganisms for removing COD are far greater than microorganisms for removing ammonia nitrogen in terms of population density and reaction rate, so that degradable COD can be considered to be degraded when ammonia nitrogen in sewage reaches the standard, and therefore real-time ammonia nitrogen value indexes become limiting factors for aeration control. When aeration control is carried out, whether the real-time ammonia nitrogen value in the aerobic tank is in a first threshold range or not can be monitored; when the real-time ammonia nitrogen value in the aerobic tank exceeds a first threshold range, adjusting the aeration rate of the blower according to a certain step so as to enable the real-time ammonia nitrogen value in the aerobic tank to reach the first threshold range; when the real-time ammonia nitrogen value in the aerobic tank is higher than the first threshold range, increasing the aeration rate of the blower according to a certain step to reduce the real-time ammonia nitrogen value in the aerobic tank; and when the real-time ammonia nitrogen value in the aerobic tank is lower than the first threshold range, reducing the aeration rate of the air blower so as to improve the real-time ammonia nitrogen value in the aerobic tank.

The real-time ammonia nitrogen value is monitored and adjusted according to a certain period, the adjustment is performed in a circulating reciprocating mode, the real-time ammonia nitrogen value in the aerobic tank is enabled to be continuously close to a first threshold range, the period and the step are set according to the retention time in the specific aerobic tank and the adjusting performance of the air blower, the period and the step can be fixed, or the period and the step can be changed, the period and the step can be adjusted in a variable mode, the period and the step are changed according to the measurement period of an ammonia nitrogen instrument and the actual hydraulic retention time of the aerobic tank, and the step is changed according to the deviation degree of the real-time ammonia nitrogen value and the historical.

For example, the period may be 30-120 min, and is not particularly limited; when the execution period is reached, detecting the real-time ammonia nitrogen value in the aerobic tank, and when the real-time ammonia nitrogen value in the aerobic tank reaches 90-110% of the target ammonia nitrogen value, keeping the state of the air blower unchanged without adjusting the air volume of the air blower; when the real-time ammonia nitrogen value in the aerobic tank is higher than 110% of the target ammonia nitrogen value, the air volume of the blower is adjusted upwards according to the range of 1% -5%; when the real-time ammonia nitrogen value in the aerobic tank 1 is lower than 90% of the target ammonia nitrogen value, the air volume of the blower is downwards adjusted according to the range of 1% -5% until the real-time ammonia nitrogen value falls within 90% -110% of the target ammonia nitrogen value.

In practical application, the aeration quantity of the air blower can be adjusted according to the real-time dissolved oxygen value in the aerobic tank, the real-time dissolved oxygen value in the aerobic tank is monitored, the real-time dissolved oxygen value is periodically compared with the second threshold range, when the real-time dissolved oxygen value is higher than the second threshold range, the aeration quantity of the air blower is reduced according to a certain step, and when the real-time dissolved oxygen value is lower than the second threshold range, the aeration quantity of the air blower is increased according to a certain step.

The real-time dissolved oxygen value is monitored and adjusted according to a certain period, and is adjusted in a circulating and reciprocating mode, so that the real-time dissolved oxygen value is reduced as far as possible on the premise that the ammonia nitrogen value reaches the first threshold range when the ammonia nitrogen value is confirmed, conditions are created for synchronous nitrification and denitrification, and the consumption of a carbon source and the energy consumption are further reduced.

For example, the period may be 15-30 min, and is not particularly limited; when the real-time dissolved oxygen value in the aerobic tank reaches 80% -120% of the target dissolved oxygen value, the air quantity of the blower does not need to be adjusted, and the state of the blower is kept unchanged; when the real-time dissolved oxygen value in the aerobic tank is higher than 120% of the target dissolved oxygen value, the air volume of the blower is downwards adjusted according to the range of 1% -5% until the real-time dissolved oxygen value falls within 80% -120% of the target dissolved oxygen value; when the real-time dissolved oxygen value in the aerobic tank is lower than 80% of the target dissolved oxygen value, the air volume of the blower is adjusted upwards according to the range of 1% -5% until the real-time dissolved oxygen value falls within 80% -120% of the target dissolved oxygen value.

In practical application, when the sewage treatment system is subjected to aeration control, the aeration quantity is controlled by ammonia nitrogen value control and dissolved oxygen or the aeration quantity is controlled by the dissolved oxygen or the ammonia nitrogen and the dissolved oxygen are shared, selection is carried out according to practical conditions, the current stage is limited by instrument technology, the measurement period of the ammonia nitrogen instrument is longer, and the measurement period of the dissolved oxygen instrument is real-time, so that the aeration quantity control period of the blower controlled by the dissolved oxygen instrument can be shortened, the response time is short, the capability of resisting upstream water quality and water quantity impact is stronger, quick response can also be realized by directly controlling the aeration quantity of the blower by the ammonia nitrogen instrument after the ammonia nitrogen instrument technology is improved later, and the method is also in the protection.

The specification also provides an aeration control method of the sewage treatment system, which comprises the following steps: monitoring a real-time ammonia nitrogen value in the aerobic tank, and judging whether the real-time ammonia nitrogen value exceeds a first threshold range; if so, adjusting the target dissolved oxygen value and determining a second threshold range based on the adjusted target dissolved oxygen value; monitoring a real-time dissolved oxygen value in the aerobic tank, and judging whether the real-time dissolved oxygen value exceeds a second threshold range; and if so, adjusting the air volume of the blower to enable the real-time dissolved oxygen value to be within a second threshold range.

In practical application, when aeration control is carried out, whether the real-time ammonia nitrogen value in the aerobic tank is in a first threshold range or not is monitored, and if the real-time ammonia nitrogen value is in the first threshold range, a target dissolved oxygen value does not need to be adjusted; if the real-time ammonia nitrogen value is higher than the first threshold range, adjusting the target dissolved oxygen value upwards in a certain step; and if the real-time ammonia nitrogen value is lower than the first threshold range, adjusting the target dissolved oxygen value downwards in a certain step.

Determining a second threshold range for judging the real-time dissolved oxygen value based on the adjusted target dissolved oxygen value after determining the adjusted target dissolved oxygen value; monitoring the real-time dissolved oxygen value, and if the real-time dissolved oxygen value is within the second threshold range, adjusting the air volume of the blower is not needed; if the real-time dissolved oxygen value is higher than the second threshold range, reducing the air volume of the blower by a certain step; and if the real-time dissolved oxygen value is lower than the second threshold range, increasing the air volume of the blower by a certain step.

For example, detecting the real-time ammonia nitrogen value in the aerobic tank, and when the real-time ammonia nitrogen value in the aerobic tank reaches 90-110% of the target ammonia nitrogen value, adjusting the target dissolved oxygen value is not needed; when the real-time ammonia nitrogen value in the aerobic tank is higher than 110% of the target ammonia nitrogen value, the target dissolved oxygen value is adjusted upwards according to the amplitude of 0.1-0.3 mg/L; and when the real-time ammonia nitrogen value in the aerobic tank is lower than 90% of the target ammonia nitrogen value, adjusting the target dissolved oxygen value downwards according to the amplitude of 0.1-0.3 mg/L.

After the adjusted target dissolved oxygen value is determined, determining that the second threshold range is 80% -120% of the adjusted target dissolved oxygen value based on the adjusted target dissolved oxygen value; monitoring the real-time dissolved oxygen value, and if the real-time dissolved oxygen value is within 80-120% of the adjusted target dissolved oxygen value, adjusting the air volume of the blower is not needed; if the real-time dissolved oxygen value is higher than 120% of the adjusted target dissolved oxygen value, adjusting the air volume of the blower downwards according to the range of 1% -5%; and if the real-time dissolved oxygen value is lower than the adjusted target dissolved oxygen value by 80%, adjusting the air volume of the blower upwards according to the range of 1-5%.

To sum up, the sewage treatment system of technology and automatic control coupling that this specification provided, through set up the aerator in good oxygen pond bottom, set up mechanical stirring device in good oxygen pond simultaneously to guarantee that the mixed liquid circulates in good oxygen pond and intensive mixing when the aeration, carry out the fast dilution to the intaking in good oxygen pond and mix, so that the water in good oxygen pond reaches the complete mixing, and the dissolved oxygen concentration is almost the same everywhere in the aquatic, avoids appearing the too high condition of local dissolved oxygen, has strengthened sewage treatment system's operating stability.

When the sewage treatment system is subjected to aeration control, the aerobic pool is subjected to low dissolved oxygen control, so that the aeration energy consumption is reduced, more importantly, conditions can be created for synchronous nitrification and denitrification, the synchronous nitrification and denitrification can account for more than 10% of the total nitrogen removal amount, the denitrification rate of an aerobic zone is improved, and the cost of an external carbon source is reduced; on the other hand, the concentration of nitrate nitrogen in effluent of the aerobic tank is reduced, so that the concentration of nitrate nitrogen in return sludge outside the secondary sedimentation tank is also reduced and returns to the anaerobic zone, the influence of nitrate nitrogen on anaerobic phosphorus release is weakened, phosphorus accumulating bacteria are facilitated to absorb small-molecular organic matters to promote phosphorus release, the biological phosphorus removal efficiency is improved, and the cost of a phosphorus removal agent is saved.

Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to intimate that the scope of the disclosure, including the claims, is limited to these examples; within the spirit of the present disclosure, features from the above embodiments or from different embodiments may also be combined, steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present description as described above, which are not provided in detail for the sake of brevity.

While the present disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations of these embodiments will be apparent to those of ordinary skill in the art in light of the foregoing description.

It is intended that the one or more embodiments of the present specification embrace all such alternatives, modifications and variations as fall within the broad scope of the appended claims. Therefore, any omissions, modifications, substitutions, improvements, and the like that may be made without departing from the spirit and principles of one or more embodiments of the present disclosure are intended to be included within the scope of the present disclosure.

Claims

1. A sewage treatment system is characterized by comprising an aerobic tank and an air blower, wherein a mechanical stirring device is arranged in the aerobic tank; an aerator is arranged at the bottom of the aerobic tank and is arranged on the air branch pipe; the inside of the aerobic tank is also provided with a dissolved oxygen instrument and an ammonia nitrogen instrument, the outside of the aerobic tank is provided with a central controller, and the central controller is respectively connected with the dissolved oxygen instrument, the ammonia nitrogen instrument and the blower.

2. The sewage treatment system of claim 1, wherein a set of U-shaped flow guide walls are further arranged in the aerobic tank and are respectively positioned at two ends of the aerobic tank.

3. The wastewater treatment system according to claim 1, wherein the number of the aerobic tanks is one or more; when the number of the aerobic tanks is multiple, a water passing opening is arranged between the adjacent aerobic tanks.

4. The wastewater treatment system according to claim 1, wherein the central controller is connected to the dissolved oxygen meter, the ammonia nitrogen meter and the blower through signal lines, respectively.

5. The wastewater treatment system according to any of claims 1-4, wherein the mechanical agitation device is one or more of a flow impeller or a vertical agitator.

6. The wastewater treatment system according to claim 1, wherein the blower is capable of minimizing the blower volume or turning off the blower when the mechanical agitator is in operation.