CN1421400A - Oxygenated water reflux type biological activated carbon wastewater treatment method and device - Google Patents

Abstract

The present invention relates to a wastewater treatment method and device using biological activated carbon in an oxygenated water reflux mode. The main purpose is that the influent water is introduced into the oxygen supply tank for aeration during the treatment process, and then the oxygen-enriched water obtained after aeration in the oxygen supply tank is sent to the bottom of the activated carbon tank, flows upward and expands the activated carbon layer. When the oxygenated water flows through the activated carbon layer, the microorganisms on the activated carbon particles will use the increased oxygen concentration to promote the decomposition and removal of pollutants such as COD, BOD, TKN, etc. in the water and adsorbed in the activated carbon. Therefore, most of the supernatant in the activated carbon tank is sent to the oxygen supply tank for aeration, and a small part is discharged as bleed water. In this way, by controlling the oxygen supply of the oxygen supply tank and the reflux ratio of oxygenated water/influent water, appropriate treatment can be performed on wastewater of different properties, and the method has the characteristics of easy operation, simple device, small reaction tank volume, low activated carbon wear, etc.

Description

Oxygenated water reflux type biological activated carbon wastewater treatment method and device

Technical field

The present invention relates to a waste water treatment method and device using a group of biologically activated carbon units combined with a group of oxygen supply units, during which the treated wastewater uses a pump to return the oxygenated water of the oxygen supply unit to the biologically activated carbon unit to Provide sufficient oxygen to microorganisms on activated carbon to remove pollutants such as COD, BOD and TKN in water/wastewater. Its application range can cover secondary treatment of wastewater, advanced treatment, advanced treatment of drinking water to remove carcinogenic precursors such as ammonia nitrogen and trihalomethanes, and the invention can also be used together with an ozone system for further treatment.

Background technique

In order to make the waste (sewage) water treatment effect reach the goal of final water quality purification, an activated carbon adsorption unit is connected to the back end of the traditional biological treatment system to remove residual pollutants such as COD, BOD, TKN, etc., which is a general environmental protection work at present. It is commonly used by technicians, but the traditionally used activated carbon adsorption unit may not be able to remove pollutants due to adsorption saturation, so the activated carbon must be discarded and renewed or regenerated to maintain the original function, which not only increases the operating manpower and The cost, and the activated carbon after disposal needs to be treated separately, which increases the treatment burden. In recent years, a biologically activated carbon treatment technology has been developed, that is, an appropriate amount of microorganisms are implanted on the activated carbon, so that it not only maintains the adsorption capacity of traditional activated carbon, but also can perform the function of biological decomposition and removal. Studies have shown that for the same Concentration of organic wastewater, the use of biological carbon can delay the adsorption and saturation of activated carbon by about 5-10 times (depending on the type and concentration of wastewater). This proves that biologically activated carbon has a great application space in the advanced treatment of waste (sewage) water. In order for the microorganisms on the activated carbon to effectively decompose the pollutants in the flowing water, sufficient oxygen supply is a necessary condition. At room temperature, the saturated dissolved oxygen in water is about 8mg/L, that is, if in the traditional fixed-bed biologically activated carbon system, only sewage flows through the biologically activated carbon bed, without additional supply of oxygen Under normal conditions, the maximum COD concentration that can be removed by biological action can only reach 8mg/L. Except for the treatment of extremely low concentration water purification, the application space of this system is extremely limited. If the inflow concentration of a certain wastewater reaches COD200mg/L, it must be treated more than thirteen times before the pollution value can be gradually degraded to below the COD100mg/L standard for effluent released in 1998, which will greatly increase the volume of the reaction tank , not enough for actual needs. In order to improve this shortcoming, the more used method is to maintain the dissolved oxygen in the biological activated carbon tower tank by means of continuous aeration, so as to improve the removal rate of pollutants. In addition, in order to obtain sufficient dissolved oxygen and agitate (fluidize) the activated carbon to increase the contact with organic matter and oxygen, it is necessary to provide sufficient kinetic energy for the intake air, but the severe aerodynamic force will generate a large shear force, and the activated carbon particles It is lost due to fragmentation caused by friction, so it needs to be replenished frequently, and the concentration of suspended particles (SS) in the discharge water is high. On the other hand, in this type of fluidized bed biological activated carbon treatment system, the filling rate of activated carbon cannot be too high (4-10 volume %), and in order to maintain a certain degree of pollutant removal rate, it is necessary to maintain more than a certain amount. The total amount of activated carbon will inevitably increase the total volume of the reaction tank, and the reaction tank must maintain a certain height or width to set up a sedimentation tank, otherwise the fluidized activated carbon will float out of the tank. The volume must be increased and the height must be increased, which will increase the overall project cost, which is a great disadvantage.

Contents of Invention

The main purpose of the present invention is to provide a new bioactivated carbon wastewater treatment technology to improve the above-mentioned shortcoming of the known technology, so that the technology can be applied to water/wastewater treatment more effectively and more economically than the known technology.

In order to achieve the above object, the wastewater treatment method of an oxygen-containing water reflux type biologically activated carbon completed according to the content of the present invention comprises the following steps:

a) Leading the waste water to be treated into an oxygen supply tank to aerate with air or other oxygen-containing gas to increase the oxygen content in the water;

b) introducing the oxygen-enriched wastewater obtained in step a) into the bottom of the reaction tank containing the biologically activated carbon bed, so that the biologically activated carbon bed is expanded, and a treated wastewater is generated at the upper part of the reaction tank;

c) releasing a part of the treated wastewater after filtering, and returning the other part to the oxygen supply tank for aeration simultaneously with the wastewater to be treated.

According to the content of the present invention, another oxygen-containing water reflux type biological activated carbon wastewater treatment method comprises the following steps:

a) introducing the wastewater to be treated into the upper part of a reaction tank containing a biologically activated carbon bed and mixing it with the treated water in the reaction tank;

b) taking out the mixed water from the upper part of the reaction tank in step a), and introducing it into an oxygen supply tank to aerate with air or other oxygen-containing gas to increase the oxygen content in the water;

c) A part of the oxygen-enriched treated water obtained in step b) is filtered and released, while the other part is refluxed to the bottom of the reaction tank, so as to expand the biologically activated carbon bed.

In the method of the present invention, the flow rate of the discharged water is substantially equal to the flow rate of the incoming waste water to be treated, and is maintained in a stable operating state.

In the method of the present invention, the ratio of the flow rate of the reflux to the flow rate of the incoming wastewater to be treated can be adjusted depending on the quality of the wastewater to be treated, and is generally about 8-30 times.

In the method of the present invention, the activated carbon in the reaction tank containing the biologically activated carbon bed is supported at a position apart from the bottom of the reaction tank, and the backflow is provided by a device between the bottom of the reaction tank and the support. between positions are introduced into the reaction tank.

A wastewater treatment device suitable for the oxygen-containing water reflux type biologically activated carbon of the present invention comprises two groups of units, one of which is a biologically activated carbon unit, and the other is an oxygen supply unit; and a backflow mechanism, wherein the biologically active Carbon unit: It includes a barrel tank as a reaction tank, and the inside of the tank is provided with uniform pipes, support materials and water collection and overflow mechanisms in sequence from the bottom of the tank. An activated carbon can be placed between the support material and the water collection and overflow mechanism The oxygen supply unit: includes an oxygen supply tank and an aeration mechanism, and the aeration mechanism introduces an air or an oxygen-containing gas into the inside of the oxygen supply tank; The liquid in the oxygen supply tank is exported and made to flow into the oxygen supply tank, and the return mechanism supplies an aerated liquid in the oxygen supply tank to the uniform pipe of the reaction tank.

There are two connection modes between the biologically activated carbon unit and the aeration unit, which are (1) combined structure: the reaction tank of the biologically activated carbon unit and the oxygen supply tank of the aeration unit are connected, that is, the two units adopt a common wall Appropriate holes are set at the common wall of the two units close to the water collection and overflow mechanism, so that water/wastewater can flow into the aeration unit smoothly from the biologically activated carbon unit, preferably a resistance is required at the opening. flow plate to prevent the water inside the oxygen supply unit from flowing back from the hole to the biologically activated carbon unit; or (2) separate type: the reaction tank of the biologically activated carbon unit and the oxygen supply tank of the aeration unit are set separately, with a The pipeline connects the reaction tank wall of the biologically activated carbon unit to the oxygen supply tank of the aeration unit near the water collection and overflow mechanism, so that a liquid located in the reaction tank is exported and flows into the oxygen supply tank, preferably Therefore, the aeration unit is lower than the activated carbon unit, so the liquid in the reaction tank is guided out by the water collection and overflow mechanism without power and flows into the oxygen supply tank.

The aeration mechanism applicable to the present invention may include a group of diffusers arranged in the oxygen supply tank and a blower or air compressor outside the oxygen supply tank, wherein the blower or air compressor blows an air Or an oxygen-containing gas is supplied to the diffuser head and dispersed into the oxygen supply tank; a submerged aerator located in the oxygen supply tank can also be used.

The return mechanism applicable to the present invention may include a return pipeline connecting the interior of the oxygen supply tank and the uniform pipe; and a land-based or submerged pump arranged on the return pipeline.

Preferably, the oxygen-containing water reflux biological activated carbon wastewater treatment device of the present invention may further include a filter to filter the discharge water discharged from the oxygen supply tank or the reaction tank.

The present invention has the following advantages: its purpose has 1. improve processing efficiency: utilize oxygenated water reflux mode, increase dissolved oxygen in water, to improve the removal efficiency of pollutant, 2. reduce the attrition of active carbon: utilize oxygenated water reflux to automatically The bottom of the activated carbon bed flows upwards to the top of the outflow, making the activated carbon layer slightly expanded, reducing friction and abrasion between particles. 3. No need to set up pre-treatment facilities: because the activated carbon bed is in an expanded state, the pores between particles will not be covered by suspended solids Blockage allows the water/wastewater treated by the sedimentation tank to flow in directly, without setting up pre-filtering treatment facilities. 4. Reduce the height of the unit: use the oxygenated water backflow method to supply oxygen and expand the activated carbon layer, not for the use of air lift Tubular type, so the height of the unit can be reduced. 5. Increase the filling rate of activated carbon: the activated carbon is not lifted by the air lift tube, so the filling rate can be increased to 60%.

Description of drawings

1A and B are flow charts of the first and second embodiments of the oxygen-containing water reflux type biological activated carbon wastewater treatment method of the present invention, respectively.

Fig. 2 is a schematic top view of a waste water treatment device (parallel structure) suitable for the oxygen-containing water reflux type biological activated carbon according to the first embodiment of the present invention.

Fig. 2A is a schematic cross-sectional view along line A-A in Fig. 2 .

Fig. 3 is a top view schematic diagram of a wastewater treatment device (separated type) suitable for the oxygen-containing water reflux type biological activated carbon according to the second embodiment of the present invention.

Fig. 3A is a schematic cross-sectional view along line A-A in Fig. 3 . Marks in the figure 1. Oxygen supply tank 2. Biologically activated carbon reaction tank 3. Return pump 4. Blower 5. Diffuser head 6. Uniform piping 7. Water collection overflow weir/channel 8. Baffle plate (parallel structure ); 8' return water pipe (separate type) 9. Support material layer 10. Activated carbon layer 11. Inflow pipe 12. Outflow pipe 13. Waste activated carbon discharge pipe 14. Air pipe 15. Oxygenated water return pipe 16, 17. Drain valve

                Specific Implementation Modes Detailed Description of Preferred Specific Embodiments 1. Oxygenated water reflux type biological activated carbon treatment device (parallel structure)

Referring to Fig. 1A and Fig. 2, the treatment procedure of the oxygen-containing water backflow type biological activated carbon treatment device of the present invention is that water/wastewater flows into the oxygen supply tank 1 from the inlet flow pipe 11, and the air provided by the blower 4 is self-dispersing through the air pipe 14 The gas head 5 enters the oxygen supply tank 1 to supply enough oxygen to dissolve in the water. The water/wastewater containing sufficient oxygen in the tank is pumped by the return pump 3 to the biological activated carbon reaction tank 2 through the oxygenated water return pipe 15 and passed through the bottom. After equalizing the water flow through the pipe 6, the activated carbon layer 10 is expanded upward through the support material layer 9, and the oxygen contained in the water/waste water will be provided to the microorganisms on the activated carbon particles or suspended in the water to decompose and remove the activated carbon layer. For organic pollutants in the particles or in the water, the return water flow rate needs to be controlled to make the activated carbon expand, but the activated carbon particles will not overflow. After the treated water is collected by the overflow weir/canal 7, a small part is discharged and passed through the outflow pipe 12 to the filter unit (not shown in the figure), after filtering out the suspended solids, let it flow, and most of it will flow back to the oxygen supply tank 1 through the opening in the middle of the two tanks, and after getting dissolved oxygen supplement from the diffuser head 5, Continue to carry out the aforementioned steps again, and set a baffle 8 at the middle partition wall to prevent the raw water/waste water flowing in from the inlet pipe 11 from backflowing and polluting the treated water. The activated carbon that has been adsorbed and saturated can be discharged by the waste activated carbon discharge pipe 13. The amount of waste should be determined by experiments. Oxygen tank 1 or bioactivated carbon reaction tank 2 can let off by drain valve 16 or 17 respectively if needing to empty and store water. 2. Oxygenated water reflux biological activated carbon treatment device (separated type)

Referring to Fig. 1B and shown in Fig. 3, the processing procedure of the oxygen-containing water backflow type biologically activated carbon treatment device of the present invention is that water/wastewater flows into the biologically activated carbon reaction tank 2 from the inlet flow pipe 11, and the air blower 4 provides air through the air pipe in addition 14 Enter the oxygen supply tank 1 from the diffuser head 5, supply enough oxygen to dissolve in the water, and the water/wastewater containing sufficient oxygen in the tank is pumped to the biological activated carbon reaction tank 2 by the return pump 3 through the oxygenated water return pipe 15 After uniform water flow through the bottom uniform pipe 6, the activated carbon layer 10 is expanded through the support material layer 9 upwards, and the oxygen contained in the water/waste water will be provided to the microorganisms on the activated carbon particles or suspended in the water for decomposition and removal of adsorption For organic pollutants in the activated carbon particles or in the water, the return water flow rate needs to be controlled to make the activated carbon expand, but the activated carbon particles will not overflow, and the treated water is collected by the overflow weir/channel 7 and then flows into the inlet pipe 11 The water/waste water in tank 2 is mixed, and then flows back to oxygen supply tank 1 through the return pipe 8' in the middle of the two tanks. After the dissolved oxygen is replenished from the diffuser head 5, the above steps are continued, and a small part of the water is in the oxygen supply tank. The upper outlet pipe 12 flows out, and then passes through a filter unit (not shown in the figure), and then discharges after filtering out suspended solids. The activated carbon that has been adsorbed and saturated can be discharged by the waste activated carbon discharge pipe 13. The amount of waste should be determined by experiments. Oxygen tank 1 or bioactivated carbon reaction tank 2 can let off by drain valve 16 or 17 respectively if needing to empty and store water.

The present invention has been tested for paper mill wastewater, pig farm wastewater and pesticide factory wastewater. These wastewater have been biologically treated in the original wastewater treatment plant, and most of the pollutants that are easily decomposed by microorganisms in the wastewater have been removed. It is not easy to do further treatment with biotechnology. After testing with the present invention, the treated water can meet the latest standard of Taiwan Province in 1987, and the effect is good. Experimental example 1. Paper mill wastewater

Experimental device scale: 6M ³ model factory

Wastewater treatment volume: 35M ³ /D

Influent water properties: secondary biological treatment water

Secondary biological treatment water COD concentration: 120～150mg/L

Bioactive carbon treated water COD concentration: <100mg/L

Operating time: 1 year

The ratio of the flow rate of the backflow to the flow rate of the inflow secondary biological treatment water is 10-20 times.

The dissolved oxygen in the oxygen supply tank and the discharged water are 6-7mg/L and 0.5-1mg/L respectively. Experimental example 2. Pig farm wastewater

Experimental device scale: 200L model factory

Amount of wastewater treated: 1.5M ³ /D

Influent water properties: secondary biological treatment water

Secondary biological treatment water COD concentration: 250~350mg/L

Bioactive carbon treated water COD concentration: <250mg/L

Operating time: 3 months

The ratio of the flow rate of the backflow to the flow rate of the inflow secondary biological treatment water is 10-20 times.

The dissolved oxygen in the oxygen supply tank and the discharged water are 6-7mg/L and 0.5-1mg/L respectively. Experimental example 3. Pesticide factory wastewater

Experimental device scale: 3.4M ³ real plants

Wastewater treatment volume: 35M ³ /D

Influent water properties: secondary biological treatment water

Secondary biological treatment water COD concentration: 150～200mg/L

Bioactive carbon treated water COD concentration: <100mg/L

Operating time: 1 year

The ratio of the flow rate of the backflow to the flow rate of the inflow secondary biological treatment water is 10-20 times.

The dissolved oxygen in the oxygen supply tank and the discharged water are 7-8mg/L and 0.5-1mg/L respectively.

It can be known from the above three experimental examples that the present invention can remove the organic pollutants contained in the secondary biological treatment water up to the discharge water standard in 1998, and the COD removal rate is about 20-50%.

Therefore compared with known technology, the progress effect of the present invention can be summarized as follows:

1. Utilize the return method of oxygenated water to increase dissolved oxygen in water and improve the removal efficiency of pollutants. Generally, the COD removal concentration can reach 50-100mg/L, and the COD removal rate can reach 20-50%.

2. Because of (1) the present invention adopts the expanded mode of activated carbon layer, it is not necessary to arrange pre-filtering facilities; The height of the unit is reduced, (3) the filling rate of activated carbon can reach 60%, and the volume of the reaction tank is reduced, so the project setting cost can be reduced compared with the known technology.

3. The present invention adopts the reflux method to expand the activated carbon layer, which reduces the friction and loss between particles, reduces the supplementary amount of activated carbon, and reduces operating costs.

In summary, the present invention can indeed meet the patent requirements, and the application is filed according to law.

Claims (23)

1. A wastewater treatment method of oxygenated water reflux type biologically activated carbon, comprising the following steps: a) Leading the waste water to be treated into an oxygen supply tank to aerate with air or other oxygen-containing gas to increase the oxygen content in the water; b) introducing the oxygen-enriched waste water obtained in step a) into the bottom of a reaction tank containing a bed of biologically activated carbon, so that the bed of biologically activated carbon is expanded, and a treated waste water is produced at the top of the reaction tank; c) releasing a part of the treated wastewater after filtering, and returning the other part to the oxygen supply tank for aeration simultaneously with the wastewater to be treated. 2. A wastewater treatment method of oxygenated water reflux type biologically activated carbon, which comprises the following steps: a) introducing the wastewater to be treated into the upper part of a reaction tank containing a biologically activated carbon bed and mixing it with the treated water in the reaction tank; b) taking out the mixed water from the upper part of the reaction tank in step a), and introducing it into an oxygen supply tank to aerate with air or other oxygen-containing gas to increase the oxygen content in the water; c) A part of the oxygen-enriched treated water obtained in step b) is filtered and discharged, while the other part is refluxed to the bottom of the reaction tank, so as to expand the biologically activated carbon bed. 3. The method according to claim 1, wherein the activated carbon of the reaction tank containing the biologically activated carbon bed is supported at a position apart from the bottom of the reaction tank, and the backflow is provided by a Between the bottom of the reaction tank and the support position is guided into the reaction tank. 4. The method according to claim 2, wherein the activated carbon of the reaction tank containing the biologically activated carbon bed is supported at a position apart from the bottom of the reaction tank, and the backflow is provided by a Between the bottom of the reaction tank and the support position is guided into the reaction tank. 5. The method according to any one of claims 1 to 4, wherein the ratio of the flow rate of the reflux to the flow rate of the incoming wastewater to be treated is 8-30 times. 6. The method as claimed in any one of claims 1 to 4, wherein the flow rate of the discharged water is substantially equal to the flow rate of the incoming wastewater to be treated so that the method is maintained in a steady state of operation. 7. The method of claim 5, wherein the flow rate of the discharged water is substantially equal to the flow rate of the incoming wastewater to be treated so that the method is maintained in a steady state of operation. 8. A wastewater treatment device for oxygen-containing water reflux type biologically activated carbon, comprising two groups of units, one of which is a biologically activated carbon unit, and the other is an oxygen supply unit; and a return mechanism, wherein the biologically activated carbon unit : Contains a bucket tank as a reaction tank, inside the tank is provided with uniform pipes, support materials and water collection and overflow mechanisms in sequence from the bottom of the tank, and an activated carbon can be placed between the support materials and the water collection and overflow mechanism; The oxygen supply unit: includes an oxygen supply tank and an aeration mechanism, and the aeration mechanism introduces an air or an oxygen-containing gas into the oxygen supply tank; The liquid is exported and made to flow into the oxygen supply tank, and the return mechanism supplies an aerated liquid located in the oxygen supply tank to the uniform pipe of the reaction tank. 9. The wastewater treatment device as claimed in claim 8, wherein the biologically activated carbon unit and the aeration unit are connected in parallel, wherein the reaction tank of the biologically activated carbon unit and the oxygen supply tank of the aeration unit are in a common The walls are connected, and a hole is opened at the common wall of the two units close to the water collection and overflow mechanism, so that the water/waste water in the reaction tank of the biological activated carbon unit flows into the oxygen supply tank of the aeration unit. 10. The wastewater treatment device as claimed in claim 9, further setting a baffle at the opening to stop the reaction of the water inside the oxygen supply tank of the oxygen supply unit flowing back from the hole to the biologically activated carbon unit in the slot. 11. The wastewater treatment device as claimed in claim 8, wherein the biologically activated carbon unit and the aeration unit are separated, wherein the reaction tank of the biologically activated carbon unit and the oxygen supply tank of the aeration unit are separately arranged, and with A pipeline connects the wall of the reaction tank of the biological activated carbon unit near the water collection and overflow mechanism to the oxygen supply tank of the aeration unit, so that a liquid located in the reaction tank is exported and flows into the oxygen supply tank. 12. The wastewater treatment device as claimed in claim 11, wherein the aeration unit is lower than the activated carbon unit, so that the liquid in the reaction tank is guided out by the water collection and overflow mechanism without power And flow into the oxygen supply tank. 13. The wastewater treatment device as claimed in any one of claims 8 to 12, wherein the aeration mechanism comprises a diffuser head arranged in the oxygen supply tank and a blower located outside the oxygen supply tank or An air compressor, wherein the blower or the air compressor supplies air or an oxygen-containing gas to the diffuser head and disperses into the oxygen supply tank. 14. The wastewater treatment device as claimed in any one of claims 8 to 12, wherein the aeration mechanism comprises a submerged aerator located in the oxygen supply tank, which supplies an air or an oxygen-containing gas into the in the oxygen supply tank. 15. The waste water treatment device as claimed in any one of claims 8 to 12, wherein the return mechanism may comprise a return line connecting the inside of the oxygen supply tank with the uniform pipe; and a return line arranged on the return line Land type or submersible pumps. 16. The waste water treatment device as claimed in claim 13, wherein the return mechanism can comprise a return line connecting the interior of the oxygen supply tank and the uniform pipe; type pump. 17. The waste water treatment device as claimed in claim 14, wherein the return mechanism can comprise a return line connecting the interior of the oxygen supply tank and the uniform pipe; and a land-type or submerged water return line arranged on the return line type pump. 18. The wastewater treatment device as claimed in any one of claims 8 to 12, further comprising a filter to filter the discharge water discharged from the oxygen supply tank or the reaction tank. 19. The wastewater treatment device as claimed in claim 13, further comprising a filter to filter the discharge water discharged from the oxygen supply tank or the reaction tank. 20. The wastewater treatment device as claimed in claim 14, further comprising a filter to filter the discharge water discharged from the oxygen supply tank or the reaction tank. 21. The wastewater treatment device as claimed in claim 15, further comprising a filter to filter the discharge water discharged from the oxygen supply tank or the reaction tank. 22. The wastewater treatment device as claimed in claim 16, further comprising a filter to filter the discharge water discharged from the oxygen supply tank or the reaction tank. 23. The wastewater treatment device as claimed in claim 17, further comprising a filter to filter the discharge water discharged from the oxygen supply tank or the reaction tank.

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