CN114195320A

CN114195320A - Rural sewage treatment system and treatment method

Info

Publication number: CN114195320A
Application number: CN202111331876.0A
Authority: CN
Inventors: 常兴龙; 裴志斌; 蒋春霞
Original assignee: De Lan Hainan Future Water Co ltd
Current assignee: De Lan Hainan Future Water Co ltd
Priority date: 2021-11-11
Filing date: 2021-11-11
Publication date: 2022-03-18

Abstract

The invention provides a rural sewage treatment system and a treatment method, comprising the following steps: the septic tank is sequentially connected with a pretreatment unit, a biochemical treatment unit and a deep treatment unit; the pretreatment unit comprises an adjusting tank for adjusting the quality of sewage, a grid channel is arranged between the adjusting tank and the septic tank, and sewage in the septic tank flows into the adjusting tank after being filtered by the grid channel; the biochemical treatment unit comprises an anaerobic tank, an anoxic tank and an aerobic tank which are connected in sequence; a lifting pump is arranged between the regulating tank and the anaerobic tank, and the sewage treated by the regulating tank is conveyed into the anaerobic tank through the lifting pump; the deep processing unit comprises an MBR membrane tank and a disinfection tank; the MBR membrane tank is connected with the aerobic tank. The system disclosed by the invention is simple in integral structure, low in treatment cost and stable and reliable in effect, and can effectively improve the sewage treatment efficiency by combining the traditional filtering mode with biological treatment.

Description

Rural sewage treatment system and treatment method

Technical Field

The invention relates to the technical field of rural sewage treatment, in particular to a rural sewage treatment system and a treatment method.

Background

With the improvement of living standard of people, the economy of rural areas is rapidly developed, but the problems of ecological environment destruction and pollution are correspondingly generated. Under the background, rural water environment is damaged by various kinds of sewage, and meanwhile, various kinds of domestic sewage can cause pathogen pollution, eutrophication pollution and the like.

The rural domestic sewage has serious problems, and the sewage sources mainly originate from the following sources:

human and animal fecal sewage: at present, the rural production mode and the life mode are obviously changed, and the human and animal excreta in the past is mainly used as fertilizer to serve the cultivated land. However, at present, more residents in rural areas tend to use convenient chemical fertilizers, so that human and animal excreta cannot be utilized, and a lot of human and animal excreta are directly discharged into a river channel without being treated, so that the human and animal excreta are an important reason for water quality pollution in rural life.

② sewage of breeding industry: with the continuous development of the urbanization process, the local economy changes in the turning over of the earth, and the traditional farming and planting process develops towards diversification. Subsidiary farming and agricultural product primary processing other than farming have also been developed, which also leads to an increase in the amount of domestic sewage.

③ bathing and washing sewage: at the present stage, the sanitation habits of people are greatly changed, and a large amount of domestic sewage is brought by daily life such as bathing, washing and the like.

Fourthly, since the domestic garbage can not be properly disposed of and can be discarded at will, a large amount of sewage is also brought by the domestic garbage and the sewage which are washed by the rain water.

The treatment of rural domestic sewage has the following difficulties:

the regional distribution is wide, and the sewage collection is difficult;

secondly, sewage water amount distribution is uneven, space-time distribution is uneven, more time is spent in farming, less time is spent in farming, more summer and autumn, less spring and winter, more morning and evening, and less noon and night;

the pollutant components have wide sources and have differences in local customs;

and fourthly, management lack and talent lack cannot effectively utilize treatment facilities well.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The invention aims to provide a rural sewage treatment system, which can remove large garbage mixed in sewage and simultaneously ensure that the pH value of the sewage meets the discharge requirement by arranging a pretreatment unit to adjust and filter the water quality of the sewage; the sewage is biochemically treated by the biochemical treatment unit, so that the sewage can be effectively purified, the cost is low, and the purification efficiency is high; through setting up deep processing unit, can promote mud-water separation, further disinfect to sewage simultaneously to guarantee that sewage reaches the emission requirement.

The second purpose of the invention is to provide a rural sewage treatment method, which is simple to operate and high in treatment efficiency and can ensure that sewage reaches the standard and is discharged.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

the invention provides a rural sewage treatment system, which comprises: the septic tank is sequentially connected with a pretreatment unit, a biochemical treatment unit and a deep treatment unit;

the pretreatment unit comprises an adjusting tank for adjusting the quality of sewage, a grid channel is arranged between the adjusting tank and the septic tank, and sewage in the septic tank flows into the adjusting tank after being filtered by the grid channel;

the biochemical treatment unit comprises an anaerobic tank, an anoxic tank and an aerobic tank which are connected in sequence; a lifting pump is arranged between the regulating tank and the anaerobic tank, and the sewage treated by the regulating tank is conveyed into the anaerobic tank through the lifting pump;

the deep processing unit comprises an MBR membrane tank and a disinfection tank; the MBR membrane tank is connected with the aerobic tank, and the sewage treated by the MBR membrane tank enters the disinfection tank; the MBR membrane tank is connected with a first dosing unit for dosing a flocculating agent.

In the prior art, the volume of the whole biochemical pool of the sewage treatment device is too large, a large factory building is needed to accommodate the biochemical pool, the manufacturing cost is high, the time is consumed, the key is difficult to achieve the effects of nitrogen and phosphorus removal, the COD of the effluent is high, and the device is not suitable for the centralized treatment of rural sewage.

In order to solve the problems, the invention provides a rural sewage treatment system which has a simple overall structure, combines the traditional filtering mode with biological treatment, can effectively improve the sewage treatment efficiency, and has low treatment cost and stable and reliable effect; the pretreatment unit is provided with a regulating tank and a grid channel, can regulate the water quality of the sewage and can remove garbage floating on the water surface of the sewage; the biochemical treatment unit sequentially carries out phosphorus release treatment in an anaerobic tank, denitrification treatment in an anoxic tank and phosphorus absorption treatment in nitrification in a denitrification aerobic tank on the sewage, so that the treatment effect on the sewage can be improved, and the biological treatment mode can also prevent secondary pollution to the sewage; the deep treatment unit is provided with an MBR membrane tank and a disinfection tank, the MBR membrane tank can promote the mud-water separation, and the disinfection tank can further sterilize the sewage, thereby ensuring that the sewage meets the discharge requirement.

Preferably, a submersible stirrer is arranged in the anaerobic tank, a first aerator is arranged in the anoxic tank, and a second aerator is arranged in the aerobic tank; the first aerator and the second aerator are both connected with aeration fans. Further, the first aerator is a perforated aerator, and the second aerator is a disc aerator. The submersible stirrer is arranged to mix the sludge and water at a uniform speed, and the first aerator and the second aerator are arranged to provide effective stirring of the sludge and provide sufficient oxygen for the biological membrane in the sludge.

Preferably, the anoxic tank and the aerobic tank are both provided with dissolved oxygen meters for monitoring the concentration of dissolved oxygen, and the dissolved oxygen meters are connected with the aeration fans to control the operation efficiency of the aeration fans. Specifically, when the dissolved oxygen meter detects that the oxygen concentration in the anoxic pond and the aerobic pond is insufficient, the aeration fan is controlled to reduce the operation efficiency, so that the oxygen transmission amount is reduced; when the dissolved oxygen meter detects that the oxygen concentration in the anoxic pond and the aerobic pond is too high, the aeration fan is controlled to improve the operation efficiency, so that the oxygen delivery amount is improved, automatic adjustment of the oxygen amount in the anoxic pond and the aerobic pond can be realized, the control precision is high, manual intervention is not needed, the workload of workers can be reduced, and the overall intelligent degree of the system is improved.

Preferably, elastic fillers for attaching biological films are arranged in the anaerobic tank, the anoxic tank and the aerobic tank; further, the elastic filler is a polyolefin material or a polyamide material. The elastic filler is arranged to ensure that the biological membrane is uniformly distributed so as to be attached to the filler to grow to the maximum extent, so that the gas, the water and the membrane can be in full contact exchange, and the removal efficiency of an anaerobic section, an anoxic section and an aerobic section is enhanced.

Preferably, the MBR membrane tank is connected with a backwashing unit for cleaning the MBR membrane tank, and the backwashing unit comprises a second medicine adding unit for adding sodium hypochlorite and a backwashing pipeline for providing backwashing water; and a water inlet of the backwashing pipeline is connected with the disinfection tank. Further, a hollow fiber corrosion-resistant film layer is arranged in the MBR membrane tank. After sewage purification accomplished, the backwash water through the backwash pipeline cleans the MBR membrane cisterna, and add the agent cell through the second simultaneously and add sodium hypochlorite in order to strengthen the cleaning performance in to the MBR membrane cisterna.

Preferably, the MBR membrane pool bottom is provided with the mud backwash pump, the mud backwash pump is connected with the mud return line, the mud return line with the anaerobism pond, the oxygen deficiency pond with good oxygen pond is linked together. The first function of the sludge backflow is to adjust the sludge concentration of the biological reaction tank, sometimes the poor settling property of the sludge may cause the concentration of the mixed liquid activated sludge in the biological reaction tank to be reduced, and a larger sludge backflow ratio is adopted to maintain the sludge concentration; the second function is that the return sludge can be regenerated, the activity can be thoroughly recovered and even enhanced in the later period of the endogenous respiration period, and the adsorption, condensation, sedimentation and degradation performance of the sludge in the state can be fully exerted after the sludge is contacted with sewage, so that the reaction process of the activated sludge can be accelerated, and the reaction effect is improved.

Preferably, the sludge treatment device further comprises a sludge storage tank, wherein an inlet of the sludge storage tank is connected with the sludge return pipeline, and an outlet of the sludge storage tank is connected with a sludge discharge pipeline; and a second liquid level meter for monitoring the liquid level in the sludge storage tank is arranged in the sludge storage tank, and the second liquid level meter is connected with a valve on the sludge discharge pipeline to control the discharge of sludge. The arrangement can realize automatic discharge of sludge.

Preferably, the disinfection tank is connected with an outward water conveying tank, and the sewage treated by the disinfection tank flows into the outward water conveying tank; the adjusting tank, MBR membrane cisterna and send out and all be provided with the first level gauge that is used for monitoring the water yield in the pond, be used for controlling the spacing sensor of low liquid level and the spacing sensor of high liquid level of business turn over water yield. Specifically, the inlet and outlet of the regulating tank, the MBR membrane tank and the delivery water tank are all provided with electromagnetic valves for controlling the inlet and outlet, the low liquid level limit sensor and the high liquid level limit sensor are all connected with the electromagnetic valves of the inlet and outlet, when the liquid level in the tank is too low, the outlet electromagnetic valve is closed, and the inlet electromagnetic valve is regulated to increase the liquid inlet amount; when the liquid level in the pool is too high, the inlet electromagnetic valve is closed, and the liquid outlet quantity of the outlet electromagnetic valve is increased, so that the intelligent control of the water quantity in the pool is realized.

Preferably, the system also comprises a waste gas treatment system, wherein the septic tank, the regulating tank, the anaerobic tank, the anoxic tank, the aerobic tank, the MBR membrane tank and the disinfection tank are connected with the waste gas treatment system so as to discharge waste gas generated in the sewage treatment process into the air after treatment.

Preferably, the outlet of the lift pump, the sludge return pipeline, the sludge discharge pipeline, the outlet pipeline of the MBR membrane tank and the discharge pipeline of the outward water supply tank are all provided with electromagnetic flow meters. The device can monitor the water inlet and outlet amount, the sludge reflux amount and the sludge discharge amount of the system in real time.

Preferably, a pH meter is arranged in the adjusting tank and used for monitoring the quality of the inlet water.

Preferably, sludge concentration detectors for monitoring the sludge concentration in the aerobic tank and the membrane tank are arranged in the aerobic tank and the MBR membrane tank. The monitored sludge concentration data of the aerobic tank and the membrane tank can be used as reference to control the sludge backflow and discharge amount.

Preferably, the pretreatment unit, the biochemical treatment unit and the deep treatment unit are all provided with monitoring equipment. The monitoring equipment is arranged to ensure timely processing of the emergency, so that the overall stability and safety of the system are improved.

The invention also provides a rural sewage treatment method, which treats sewage through the rural sewage treatment system. The method has the advantages of simple operation, large treatment capacity and high treatment efficiency, and the treated sewage meets the discharge requirement.

Compared with the prior art, the invention has the beneficial effects that:

(1) the system disclosed by the invention is simple in integral structure, the traditional filtering mode is combined with biological treatment, the sewage treatment efficiency can be effectively improved, the treatment cost is low, and the effect is stable and reliable;

(2) the pretreatment unit is provided with the adjusting tank and the grid channel, so that the water quality of the sewage can be adjusted, and meanwhile, garbage floating on the water surface of the sewage can be removed;

(3) by arranging the anaerobic tank, the anoxic tank and the aerobic tank in the biochemical treatment unit, the sewage is subjected to phosphorus release in the anaerobic tank, denitrification in the anoxic tank and phosphorus absorption by nitrification in the denitrification aerobic tank in sequence, the sewage treatment effect can be improved, and the biological treatment mode can also prevent secondary pollution to the sewage;

(4) the deep treatment unit is provided with an MBR membrane tank and a disinfection tank, the MBR membrane tank can promote sludge-water separation, and the disinfection tank can further sterilize the sewage, so that the sewage can meet the discharge requirement;

(5) through setting up instruments such as level gauge, solenoid valve, electromagnetic flowmeter in each workshop section, can realize sewage treatment process's automated control, reduce staff's work load, improved managerial efficiency and sewage treatment efficiency.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a schematic structural view of a rural sewage treatment system provided by an embodiment of the present invention.

Wherein:

1-a septic tank; 2-grid channel;

3-a regulating reservoir; 4-a mud storage pool;

5-a sludge discharge pipeline; 6-sludge return line;

7-a second level gauge; 8-a first level gauge;

9-anoxic pond; 10-a first aerator;

11-dissolved oxygen instrument; 12-an aerobic tank;

13-sludge reflux pump; 14-membrane scouring blower;

15-MBR membrane tank; 16-transporting the water pool outside;

17-a disinfection tank; 18-backwash line;

19-a second dosing unit; 20-a first dosing unit;

21-an aeration fan; 22-a second aerator;

23-a submersible mixer; 24-a lift pump;

25-anaerobic pool.

Detailed Description

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In order to more clearly illustrate the technical solution of the present invention, the following description is made in the form of specific embodiments.

Examples

Referring to fig. 1, the present embodiment provides a rural sewage treatment system, including: the septic tank 1, the septic tank 1 connects with pretreatment unit, biochemical treatment unit and deep processing unit sequentially;

the pretreatment unit comprises an adjusting tank 3 for adjusting the quality of sewage, a grid channel 2 is arranged between the adjusting tank 3 and the septic tank 1, and the sewage in the septic tank 1 flows into the adjusting tank 3 after being filtered by the grid channel 2;

wherein, a pH meter is arranged in the adjusting tank 3 and is used for monitoring the quality of the inlet water.

The biochemical treatment unit comprises an anaerobic tank 25, an anoxic tank 9 and an aerobic tank 12 which are connected in sequence; a lifting pump 24 is arranged between the adjusting tank 3 and the anaerobic tank 25, and the sewage treated by the adjusting tank 3 is conveyed into the anaerobic tank 25 through the lifting pump 24;

wherein, a submersible mixer 23 is arranged in the anaerobic tank 25, a first aerator 10 is arranged in the anoxic tank 9, and a second aerator 22 is arranged in the aerobic tank 12; the first aerator and the second aerator are both connected with an aeration fan 21. Further, the first aerator 10 is a perforated aerator, and the second aerator 22 is a disc aerator. The submersible stirrer is arranged to mix the sludge and water at a uniform speed, and the first aerator and the second aerator are arranged to provide effective stirring of the sludge and provide sufficient oxygen for the biological membrane in the sludge.

In order to facilitate monitoring of the concentration of dissolved oxygen, dissolved oxygen meters 11 are arranged in the anoxic tank 9 and the aerobic tank 12, and the dissolved oxygen meters 11 are connected with the aeration fan 21 to control the operation efficiency of the aeration fan 21. Specifically, when the dissolved oxygen meter 11 detects that the oxygen concentration in the anoxic tank 9 and the aerobic tank 12 is insufficient, the aeration fan 21 is controlled to reduce the operation efficiency, so that the oxygen delivery amount is reduced; when the dissolved oxygen meter 11 detects that the oxygen concentration in the anoxic tank 9 and the aerobic tank 12 is too high, the aeration fan 21 is controlled to improve the operation efficiency, so that the oxygen delivery amount is improved.

In the embodiment, elastic fillers for attaching biological films are arranged in the anaerobic tank 25, the anoxic tank 9 and the aerobic tank 12; the elastic filler can be made of polyolefin materials or polyamide materials. The elastic filler can ensure that the biological membrane is attached to the maximum extent, so that the gas, the water and the membrane can be in full contact exchange, and the removal efficiency of anaerobic, anoxic and aerobic sections is enhanced.

The deep processing unit comprises an MBR membrane tank 15 and a disinfection tank 17; the MBR membrane tank 15 is connected with the aerobic tank 12, and the sewage treated by the MBR membrane tank 15 enters the disinfection tank 17; the MBR membrane tank 15 is connected with a first dosing unit 20 for dosing a flocculating agent.

Wherein, the bottom of the MBR membrane tank 15 is provided with a sludge return pump 13, the sludge return pump 13 is connected with a sludge return pipeline 6, and the sludge return pipeline 6 is communicated with the anaerobic tank 25, the anoxic tank 9 and the aerobic tank 12. The disinfection tank 17 is connected with an outward water conveying tank 16, and the sewage treated by the disinfection tank 17 flows into the outward water conveying tank 16. Sludge concentration detectors for monitoring the sludge concentration of the aerobic tank 12 and the membrane tank are arranged in the aerobic tank 12 and the MBR membrane tank 15. The monitored sludge concentration data of the aerobic tank 12 and the membrane tank can be used as reference to control the sludge backflow and discharge amount.

In this embodiment, the regulating reservoir 3, the MBR membrane reservoir 15 and the delivery water reservoir 16 are all provided with a first liquid level meter 8 for monitoring the amount of water, a low liquid level limit sensor and a high liquid level limit sensor for controlling the amount of water fed and discharged. Specifically, the inlets and outlets of the regulating tank 3, the MBR membrane tank 15 and the delivery water tank 16 are all provided with electromagnetic valves for controlling the inlet and outlet, the low liquid level limit sensor and the high liquid level limit sensor are all connected with the electromagnetic valves of the inlets and outlets, when the liquid level in the tanks is too low, the outlet electromagnetic valve is closed, and the inlet electromagnetic valve is regulated to increase the liquid inlet amount; when the liquid level in the pool is too high, the inlet electromagnetic valve is closed, and the liquid outlet quantity of the outlet electromagnetic valve is increased, so that the intelligent control of the water quantity in the pool is realized.

In order to facilitate the cleaning of the MBR membrane tank 15, the MBR membrane tank 15 is connected with a backwashing unit for cleaning the MBR membrane tank 15, and the backwashing unit comprises a second medicine adding unit 19 for adding sodium hypochlorite and a backwashing pipeline 18 for providing backwashing water; the water inlet of the backwashing pipe 18 is connected with the disinfection tank 17. In this embodiment, a hollow fiber corrosion-resistant film layer is disposed in the MBR membrane tank 15. After sewage purification accomplished, the backwash water through backwash pipeline 18 cleans MBR membrane cisterna 15, and add sodium hypochlorite in order to strengthen the cleaning performance to MBR membrane cisterna 15 through second medicine unit 19 simultaneously. The second dosing unit 19 is further connected to a disinfection tank 17 for providing disinfection agent to the disinfection tank 17. In addition, a membrane scouring fan 14 is connected to the MBR membrane tank 15 to further clean the membranes in the MBR membrane tank 15.

The system of the embodiment also comprises a sludge storage tank 4, wherein the inlet of the sludge storage tank 4 is connected with a sludge return pipeline 6, and the outlet of the sludge storage tank 4 is connected with a sludge discharge pipeline 5; a second liquid level meter 7 for monitoring the liquid level in the sludge storage tank 4 is arranged in the sludge storage tank 4, and the second liquid level meter 7 is connected with a valve on the sludge discharge pipeline 5 to control the discharge of sludge. The arrangement can realize automatic discharge of sludge.

In order to reduce the occupied area of the system, the anaerobic tank 25, the anoxic tank 9, the aerobic tank 12, the MBR membrane tank 15, the disinfection tank 17 and the outward water conveying tank 16 are arranged in the same shell and are separated from each other by partition plates.

In order to prevent the air from being polluted by the waste gas generated in the sewage treatment process, the system of the embodiment further comprises a waste gas treatment system (not shown in the figure), and the septic tank 1, the regulating tank 3, the anaerobic tank 25, the anoxic tank 9, the aerobic tank 12, the MBR membrane tank 15 and the disinfection tank 17 are all connected with the waste gas treatment system so as to discharge the waste gas generated in the sewage treatment process into the air after being treated.

In this embodiment, the outlet of the lift pump 24, the sludge return line 6, the sludge discharge line 5, the outlet line of the MBR membrane tank 15, and the discharge line of the outward water supply tank 16 are all provided with electromagnetic flow meters.

In order to facilitate the remote monitoring of workers, the pretreatment unit, the biochemical treatment unit and the deep treatment unit are provided with monitoring equipment.

When the device is used, sewage of villages and towns is collected into the septic tank 1 through a pipe network for primary clarification and anaerobic treatment, the sewage in the septic tank 1 enters the regulating tank 3 after being filtered by the grid channel 2, is discharged by the lift pump 24 after being neutralized with water quality and water quantity in the regulating tank 3, and is discharged into the MBR membrane tank 15 for sludge-water separation after being biochemically treated by the anaerobic tank 25, the anoxic tank 9 and the aerobic tank 12 in sequence; a first dosing unit 20 adds a flocculating agent into the MBR membrane tank 15 to further remove phosphorus; the water produced by the membrane tank enters a disinfection tank 17 for disinfection treatment, the disinfected water produced enters an outward water delivery tank 16, and the water in the outward water delivery tank 16 can be used for greening or directly discharged.

Examples of the experiments

The bathing, the toilet, the brushing, the street rainwater and the like in a certain village are connected into the septic tank of the system of the embodiment through a sewage collecting pipe network, and the water quality conditions of the inlet water and the outlet water for 6 days are recorded.

TABLE 1 Water inflow and quality data

TABLE 2 Water discharge quantity and quality meter

The result shows that the combined operation of the process monitors and analyzes the water quality and water quantity data of the sewage station which continuously operates for 6 days, and the process can ensure that the water quality of the discharged water can stably reach the standard when the water quantity changes greatly. The discharge standard can reach the first grade A standard in discharge Standard for urban Sewage treatment (GB18918-2002), and meets the national discharge requirement for urban sewage treatment.

Comparing the COD indexes in the table 1 and the table 2, the highest COD concentration of the inlet water is 328.6mg/L, the lowest COD concentration of the inlet water is 234.3mg/L, and the average COD concentration of the inlet water is 289.77 mg/L; after the treatment by the system, the highest COD concentration of the effluent is 42.86mg/L, the lowest COD concentration is 21.53mg/L, the average COD concentration of the effluent is 34.71mg/L, and the average COD removal rate is 88.02 percent, which is far superior to the first-class A standard of discharge Standard of urban wastewater treatment.

Comparing the ammonia nitrogen indexes in the table 1 and the table 2, the highest ammonia nitrogen concentration of the inlet water is 54.8mg/L, the lowest ammonia nitrogen concentration of the inlet water is 21.09mg/L, and the average ammonia nitrogen concentration of the inlet water is 30.42 mg/L; after the treatment by the system, the highest concentration of the ammonia nitrogen in the effluent is 3.43mg/L, the lowest concentration of the ammonia nitrogen is 2.05mg/L, the average concentration of the ammonia nitrogen in the effluent is 2.89mg/L, and the average removal rate of the ammonia nitrogen is 90.50 percent, which is far superior to the first-level A standard of discharge standard of urban wastewater treatment.

Comparing the total nitrogen indexes in the table 1 and the table 2, the highest total nitrogen concentration of the inlet water is 53.45mg/L, the lowest total nitrogen concentration of the inlet water is 30.2mg/L, and the average total nitrogen concentration of the inlet water is 37.38 mg/L; after the treatment by the system, the highest concentration of total nitrogen in effluent is 11.24mg/L, the lowest concentration of total nitrogen is 6.89mg/L, the average concentration of total nitrogen in effluent is 8.39mg/L, and the average total nitrogen removal rate is 77.55 percent, which is far superior to the first-class A standard of discharge Standard of urban wastewater treatment.

Comparing the total phosphorus indexes in the table 1 and the table 2, the highest total phosphorus concentration of the inlet water is 3.24mg/L, the lowest total phosphorus concentration of the inlet water is 2.05mg/L, and the average total phosphorus concentration of the inlet water is 2.60 mg/L; after the treatment by the system, the highest concentration of total phosphorus in the effluent is 0.45mg/L, the lowest concentration of total phosphorus is 0.25mg/L, the average concentration of total phosphorus in the effluent is 0.34mg/L, and the average total phosphorus removal rate is 86.92%, which is far superior to the first-class A standard of discharge Standard of urban wastewater treatment.

Comparing the suspended matter indexes in the table 1 and the table 2, the highest suspended matter concentration of the inlet water is 321mg/L, the lowest suspended matter concentration of the inlet water is 89mg/L, and the average inlet water suspended matter concentration is 181 mg/L; after the treatment by the system, the highest concentration of the suspended matters in the effluent is 8mg/L, the lowest concentration of the suspended matters is 5mg/L, the average concentration of the suspended matters in the effluent is 6.5mg/L, and the average removal rate of the suspended matters is 96.41 percent, which is far superior to the first-class A standard of discharge standard of urban sewage treatment.

In a word, the system disclosed by the invention is simple in integral structure, low in treatment cost and stable and reliable in effect, and can effectively improve the sewage treatment efficiency by combining the traditional filtering mode with biological treatment.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rural sewage treatment system is characterized by comprising: the septic tank is sequentially connected with a pretreatment unit, a biochemical treatment unit and a deep treatment unit;

2. The rural sewage treatment system of claim 1, wherein a submersible mixer is arranged in the anaerobic tank, a first aerator is arranged in the anoxic tank, and a second aerator is arranged in the aerobic tank; the first aerator and the second aerator are both connected with aeration fans.

3. The rural sewage treatment system of claim 2, wherein the first aerator is a perforated aerator and the second aerator is a disc aerator.

4. The rural sewage treatment system of claim 3, wherein a dissolved oxygen meter for monitoring the concentration of dissolved oxygen is arranged in each of the anoxic tank and the aerobic tank, and the dissolved oxygen meter is connected with the aeration fan to control the operation efficiency of the aeration fan.

5. The rural sewage treatment system of claim 2, wherein the anaerobic tank, the anoxic tank and the aerobic tank are all provided with elastic fillers for attaching biological membranes.

6. The rural sewage treatment system of claim 1, wherein the MBR membrane tank is connected with a backwashing unit for cleaning the MBR membrane tank, and the backwashing unit comprises a second dosing unit for dosing sodium hypochlorite and a backwashing pipeline for providing backwashing water; and a water inlet of the backwashing pipeline is connected with the disinfection tank.

7. The rural sewage treatment system of claim 6, wherein a sludge return pump is arranged at the bottom of the MBR membrane tank, and is connected with a sludge return pipeline which is communicated with the anaerobic tank, the anoxic tank and the aerobic tank.

8. The rural sewage treatment system of claim 7, further comprising a sludge storage tank, wherein an inlet of the sludge storage tank is connected with the sludge return line, and an outlet of the sludge storage tank is connected with a sludge discharge line; and a second liquid level meter for monitoring the liquid level in the sludge storage tank is arranged in the sludge storage tank, and the second liquid level meter is connected with a valve on the sludge discharge pipeline to control the discharge of sludge.

9. The rural sewage treatment system of claim 1, wherein the disinfection tank is connected with a water delivery tank, and sewage treated by the disinfection tank flows into the water delivery tank;

the adjusting tank, the MBR membrane tank and the delivery water tank are internally provided with a first liquid level meter for monitoring the water quantity, a low liquid level limit sensor and a high liquid level limit sensor for controlling the water inlet and outlet quantity.

10. A rural sewage treatment method, which is characterized in that sewage is treated by the rural sewage treatment system of any one of claims 1-9.