CN1329316C - Activated sludge dephosphorizing and denitrifying method with alternated water intake from multi-spots - Google Patents

Abstract

The multi-point alternate feed activated sludge dephosphorization and nitrogen removal method is a sewage treatment engineering technology in environmental engineering, especially an economical and practical advanced technology suitable for domestic sewage and urban sewage dephosphorization and denitrification. The reaction of multi-point alternate feed The tank body (1) consists of five reaction tanks and a sedimentation tank connected in series to form a closed loop connection; the five reaction tanks are hydraulically connected by connecting pipes (16), and each reaction tank is equipped with a perforated aeration pipe (17) , agitator (2), water inlet solenoid valve (5), inlet solenoid valve (8), sludge return solenoid valve (15); one operation cycle is composed of six stages: stage one, stage two, stage three Half cycle, stage 4, stage 5, and stage 6 constitute the other half cycle, and the two half cycles are mutually symmetrical; the water inlet point changes alternately from stage 1 to stage 6, and the sludge mixture changes in the upper and lower half cycles with the direction of water flow. To flow, to achieve automatic backflow.

Description

Multi-point Alternate Feed Activated Sludge Phosphorus and Nitrogen Removal Method

technical field

The invention is a sewage treatment engineering technology in environmental engineering, especially an economical and practical advanced technology suitable for removing phosphorus and nitrogen from domestic sewage and urban sewage, and belongs to the technical field of environmental protection.

Background technique

At present, the level of sewage treatment in my country is relatively low, the ammonia nitrogen and total phosphorus in the main water systems and lakes are seriously exceeded, the problem of eutrophication is prominent, and the phenomenon of red tides in coastal waters occurs from time to time. To control water pollution, the first step is to control the sources of nitrogen and phosphorus pollution discharged into the water. Nitrogen and phosphorus pollution in water mainly comes from domestic sewage and agricultural non-point source pollution, among which domestic sewage is the main source of pollution in many water bodies. How to strengthen decentralized domestic sewage treatment is of great significance for controlling water pollution. my country's "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18918-2002) has strictly limited the nitrogen and phosphorus indicators in the discharged sewage. At present, large-scale urban sewage treatment plants have formed a mature process for phosphorus and nitrogen removal, but the effect of phosphorus and nitrogen removal in practical applications is not very satisfactory. However, most of the small and medium-sized scattered sewage have not been treated, and most of the existing treatments are at the first-level treatment level, and the measures for phosphorus and nitrogen removal are rarely taken. my country's "Urban Sewage Treatment and Pollution Prevention Technology Policy" stipulates that my country's sewage treatment should adhere to the combination of concentration and decentralization. While strengthening the centralized treatment of urban sewage, attention should be paid to the treatment of decentralized sewage. Wastewater from semi-closed water bodies is treated for phosphorus and nitrogen removal.

Therefore, it is imminent to research and develop an economical and efficient advanced treatment process for phosphorus and nitrogen removal of sewage that is suitable for different treatment scales and my country's national conditions.

Contents of the invention

Technical problem: The purpose of this invention is to provide a method for dephosphorization and denitrification of activated sludge with multi-point alternate water inlet, which is suitable for sewage biological treatment with various treatment scales that require descaling and denitrification, and can meet the requirements of pollutant degradation and denitrification. Phosphorus denitrification requirements, at the same time, the process adopts the combination of time control and real-time control, which is beneficial to realize the intelligentization of the process.

Technical solution: The multi-point alternate water inlet reaction tank body of the present invention is composed of five reaction tanks and a sedimentation tank connected in series to form a closed loop connection; the five reaction tanks are hydraulically connected by connecting pipes, and each reaction tank is equipped with Perforated aeration pipe, agitator, water inlet solenoid valve, inlet solenoid valve, sludge return solenoid valve; one operation cycle consists of six stages:

Stage 1. The sewage enters the first and second ponds, and the sludge flows back into the fourth pond.

Phase 2. Sewage enters the first and third pools, and the sludge flows back into the third pool.

Stage 3. All the sewage enters the second pool, and the sludge returns to the second pool.

Stage 4. Sewage enters the fifth pool and the fourth pool, and the sludge flows back into the second pool.

Stage 5. Sewage enters the fifth pool and the third pool, and the sludge flows back into the third pool.

Stage 6. All the sewage enters the fourth pool, and the sludge returns to the fourth pool;

Stage 1, stage 2, and stage 3 constitute a half cycle, and stage 4, stage 5, and stage 6 constitute the other half cycle, and the two half cycles are symmetrical to each other; the water inlet point changes alternately from stage 1 to stage 6, and the sludge mixture changes with time. The direction of the water flow is reversed in the upper and lower half-cycles to realize automatic backflow. The flow directions of the different half-cycle water flows in the tank body are clockwise or counterclockwise on the plane, and flow to the end of a reaction tank and between the sedimentation tank. The communication valve of the first reaction tank and the sedimentation tank in the upstream is closed.

The control method adopts a combination of time control and real-time control with oxidation-reduction potential (ORP) and dissolved oxygen (DO) as parameters. The specific control scheme can be set as follows: based on time control, the five reaction pools are respectively fixed Dissolved oxygen DO and redox potential ORP online detection probes track the continuous change signal of redox potential ORP when it is in the function of denitrification or phosphorus release. If the redox potential ORP fluctuates or rises for a long time, it will be fed back to the program The controller feeds water into the pond or increases the water intake to provide organic matter enhanced phosphorus and nitrogen removal effects; when performing nitrification, phosphorus absorption, and organic matter degradation functions, the DO signal is collected. When the DO is stable, the DO should be Maintained above 4mg/L, the dissolved oxygen DO concentration maintained when the temperature is low should increase.

The present invention utilizes an integrated pool composed of five biochemical reaction pools (boxes) and a settling tank, through the alternate transformation of the position of the water inlet point, the automatic backflow of the mixed liquid and the backflow of part of the sludge are realized. The separated sedimentation tank returns a small amount of sludge (about 25%) from the sedimentation tank to the water inlet; the process runs periodically. Through the sequential advancement of water in each tank and the conversion of stirring and aeration control states, it experiences anoxic, anaerobic and aerobic environments in space; each reaction tank also undergoes anoxic and anaerobic environments in one cycle. , The conversion of aerobic state, so the water intake time has also experienced the replacement of anoxic, anaerobic and aerobic environments. The process can realize the control mode of time control and real-time control, combined with automation design, it can realize the intelligentization of process control.

Beneficial effect: the present invention has following characteristics:

(1) The process alternates the anaerobic/anoxic and aerobic states of each reaction pool with time and space, so that all the influent has experienced anoxic, anaerobic, and aerobic environments; at the same time, it creates a more stringent reaction Nitrification, phosphorus release and nitrification environment, high efficiency of phosphorus and nitrogen removal.

(2) No special mixed liquid return device is installed. In the symmetrical two and a half cycles, the water flow direction is changed by switching the water inlet and outlet positions to automatically complete the mixed liquid return; the sludge return ratio is small and the power consumption is small.

(3) The process can realize the control mode of time control and real-time control, and the use of oxidation-reduction potential (ORP) and dissolved oxygen (DO) signal detection and program control can realize the intelligentization of process control and effectively coordinate denitrification and phosphorus release requirements for organic matter in influent water.

(4) It is suitable for sewage biological treatment of various scales that require descaling and denitrification, and medium and small scales can realize equipment production.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Figure 1 is a schematic diagram of the structure of the method for removing phosphorus and nitrogen from multi-point alternately fed activated sludge, which includes a tank body 1, agitator 2, water inlet pipe 3, water inlet flow meter 4, water inlet solenoid valve 5, air inlet pipe 6, Gas flow meter 7, intake solenoid valve 8, sludge return pump 9, sludge return pipe 10, sludge flow meter 11, outlet pipe 12, outlet weir 13, sludge discharge pipe 14, sludge return solenoid valve 15, communication Pipe 16, perforated aeration pipe 17, gate valve 18, butterfly valve 19, communication valve 20, mud discharge electromagnetic valve 21.

Fig. 2 is a schematic diagram of the control system of the method for removing phosphorus and nitrogen from the activated sludge with multi-point alternate feeding.

Figure 3 is a schematic diagram of the operation process of the method for removing phosphorus and nitrogen from activated sludge with multi-point alternate water feeding.

Detailed ways

In the method for dephosphorization and denitrification of activated sludge with multi-point alternate water inlet of the present invention, the reaction tank body 1 of multi-point alternate water inlet is composed of five reaction tanks and a sedimentation tank connected in series to form a closed loop connection; wherein the five reaction tanks are connected by The connecting pipe 16 is hydraulically connected, and the connecting pipes are staggered to prevent short flow. Each reaction tank is equipped with a perforated aeration pipe 17, agitator 2, water inlet electromagnetic valve 5, air inlet electromagnetic valve 8, and sludge return electromagnetic valve. Valve 15; an operating cycle consists of six phases:

Stage one. Sewage enters the first pond and the second pond, the agitator 2 of the first pond, the second pond, and the fourth pond is opened, and the intake electromagnetic valve 8 of the third pond and the fifth pond is opened (when the agitator 2 is opened The intake solenoid valve 8 is closed, the agitator 2 is closed when the intake solenoid valve 8 is opened, and the following stages are the same), the sludge return solenoid valve 15 of the fourth pool is opened, and the sludge in the sedimentation tank is passed through the sludge by the sludge return pump 9 The return pipe 10 flows back into the fourth pool,

Stage 2. Sewage enters the first and third pools, the agitators 2 of the first, third, and fourth pools are turned on, the intake solenoid valves 8 of the second and fifth pools are turned on, and the sludge in the third pool is The return solenoid valve 15 is opened, and the sludge in the sedimentation tank is returned to the third pool by the sludge return pump 9 through the sludge return pipe 10,

Phase 3. All the sewage enters the second pool, the agitator 2 of the second pool, the third pool, and the fourth pool is turned on, the intake solenoid valve 8 of the first pool and the fifth pool is opened, and the sludge return solenoid valve of the second pool 15 is turned on, and the sludge in the sedimentation tank is returned to the second pool by the sludge return pump 9 through the sludge return pipe 10,

Stage 4. Sewage enters the fifth pool and the fourth pool, the agitator 2 of the second pool, the fourth pool, and the fifth pool is turned on, the intake solenoid valve 8 of the first pool and the third pool is opened, and the sludge in the second pool is The return solenoid valve 15 is opened, and the sludge in the sedimentation tank is returned to the second pool by the sludge return pump 9 through the sludge return pipe 10,

Stage 5. Sewage enters the fifth pool and the third pool, the agitator 2 of the second pool, the third pool, and the fifth pool is turned on, the intake solenoid valve 8 of the first pool and the fourth pool is opened, and the sludge in the third pool is The return solenoid valve 15 is opened, and the sludge in the sedimentation tank is returned to the third pool by the sludge return pump 9 through the sludge return pipe 10,

Phase 6. All the sewage enters the fourth pool, the agitator 2 of the second pool, the third pool, and the fourth pool is turned on, the intake solenoid valve 8 of the first pool and the fifth pool is opened, and the sludge return solenoid valve of the fourth pool 15 is turned on, and the sludge in the sedimentation tank flows back into the fourth pool through the sludge return pipe 10 through the sludge return pump 9;

Stage 1, stage 2, and stage 3 constitute a half cycle, and stage 4, stage 5, and stage 6 constitute the other half cycle, and the two half cycles are symmetrical to each other; the water inlet point changes alternately from stage 1 to stage 6, and the sludge mixture changes with time. The direction of the water flow is reversed in the upper and lower two half-cycles to realize the automatic return of the mixed liquid. It only needs to increase the sludge return by about 25% to meet the needs of phosphorus and nitrogen removal. The flow directions of different half-cycle water flows in the pool body 1 are clockwise or counterclockwise on the plane, and the connecting valve 20 between the reaction tank and the sedimentation tank at the end of the flow is opened, and the upstream first reaction tank and the sedimentation tank are connected. The connecting valve 20 is closed. Water intake, aeration, stirring or sludge return in different pools are all realized by the PLC controller controlling the opening of solenoid valves (electric valves, etc.).

Multi-point alternate water inlet and sludge return point change can make the process meet more stringent conditions of denitrification, phosphorus release, nitrification and phosphorus absorption.

The control method adopts the combination of time control and real-time control with oxidation-reduction potential ORP and dissolved oxygen DO as parameters. The specific control scheme can be set as follows: based on time control, the dissolved oxygen DO, The redox potential ORP online detection probe, when it is in the function of denitrification or phosphorus release, tracks the continuous change signal of the redox potential ORP. If the redox potential ORP fluctuates or rises for a long time, it will be fed back to the program controller. Water inflow to the pond or increase the amount of water inflow to provide organic matter to strengthen the effect of phosphorus and nitrogen removal; when performing nitrification, phosphorus absorption and organic matter degradation functions, collect dissolved oxygen DO signals. When dissolved oxygen DO is stable, dissolved oxygen DO should be maintained at 4mg/ Above L, the dissolved oxygen DO concentration maintained when the temperature is low should increase.

Claims (2)

1. A method for dephosphorization and denitrification of activated sludge with multi-point alternate water inlet is characterized in that the reaction tank body (1) of multi-point alternate water inlet is connected in series by five reaction tanks and a settling tank to form a closed loop connection; five of them The connecting pipes (16) are hydraulically connected between the two reaction tanks, and each reaction tank is provided with a perforated aeration pipe (17), an agitator (2), a water inlet solenoid valve (5), and an air inlet solenoid valve (8). , sludge return solenoid valve (15); an operation cycle is made up of six stages: Stage 1. The sewage enters the first and second ponds, and the sludge flows back into the fourth pond. Phase 2. Sewage enters the first and third pools, and the sludge flows back into the third pool. Stage 3. All the sewage enters the second pool, and the sludge returns to the second pool. Stage 4. Sewage enters the fifth pool and the fourth pool, and the sludge flows back into the second pool. Stage 5. Sewage enters the fifth pool and the third pool, and the sludge flows back into the third pool. Stage 6. All the sewage enters the fourth pool, and the sludge returns to the fourth pool; Stage 1, stage 2, and stage 3 constitute a half cycle, and stage 4, stage 5, and stage 6 constitute the other half cycle, and the two half cycles are symmetrical to each other; the water inlet point changes alternately from stage 1 to stage 6, and the sludge mixture changes with time. The direction of water flow is reversed in the upper and lower half-cycles to realize automatic backflow. The flow directions of different half-cycle water flows in the pool body (1) are clockwise or counterclockwise on the plane, and flow to a reaction pool at the end and The communication valve (20) between the sedimentation tanks is opened, and the communication valve (20) between the upstream first reaction tank and the sedimentation tank is closed. 2. The method for dephosphorization and denitrification by the activated sludge method of multi-point alternating water inflow according to claim 1, characterized in that the control mode adopts the control mode combining time control and real-time control with redox potential and dissolved oxygen as parameters , the specific control scheme is set as follows: based on time control, fixed dissolved oxygen and redox potential online detection probes are respectively fixed in the five reaction pools. If the reduction potential fluctuates or rises for a long time, it will be fed back to the program controller to feed water into the pool or increase the water intake to provide organic matter enhanced phosphorus and nitrogen removal effects; when performing nitrification, phosphorus absorption and organic matter degradation functions, collect Dissolved oxygen signal, when the dissolved oxygen is stable, the dissolved oxygen should be maintained above 4mg/L, and the dissolved oxygen concentration should be increased when the temperature is low.

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