KR101662491B1 - Method of sewage treatment - Google Patents

Abstract

A sewage treatment method is disclosed. The sewage treatment method comprises: separating raw sludge in initial sewage introduced through a primary precipitation tank; discharging phosphorus removing organic matter from the sewage through an anaerobic tank; denitrifying the sewage and removing the organic matter from the sewage through an anoxic tank; performing nitrification of the sewage and oxidation of the organic matter through an aerobic tank; and separating residual sludge through a secondary precipitation tank; and a sludge concentration and dehydration step of converting the sludge transferred from the first and second precipitation tanks into sludge cake through a concentration/dehydration facility. The aerobic tank includes: an aeration unit for inserting air into the aerobic tank; an immersion-type separator module including a membrane for solids-liquid separation of the sewage passing the aerobic tank; a fluid circulation device for circulation of the sewage supplied to the aerobic tank; compressed activated carbon supplied into the aerobic tank, composed of compressed activated carbon having a size of 3 mm to 5 mm and a specific gravity corresponding to the specific gravity of water, and colliding with an immersion-type separator while circulated together with the sewage inside the aerobic tank by the aeration unit and fluid circulation device; an activated carbon supply unit for supplying the compressed activated carbon to the aerobic tank; and an activated carbon collection unit collecting fragments of the activated carbon floating on the surface of the sewage in the aerobic tank. Thus, it is possible to collect the floating activated carbon and to delay congestion in the immersion-type separator at the same time.

Description

{METHOD OF SEWAGE TREATMENT}

The present invention relates to a sewage treatment method, and more particularly, to a sewage treatment method capable of reducing clogging due to the formation of foreign substances in a water treatment separation membrane and improving the heat quantity of biofuel produced from concentrated and dewatered sludge.

In the process using immersion type membranes (membrane modules) used for water treatment, clogging of membranes due to adherence of foreign matters to membranes and microorganisms or membranes is a factor that greatly influences the operation of the membrane process and the lifetime of membranes. If the separation membrane is contaminated, it is necessary to regularly clean the separation membrane by using air, water, or water containing a small amount of chemical to remove the material blocking the separation membrane, or to convert the separation membrane into another separation membrane In this case, there are problems such as an increase in manpower and maintenance cost for cleaning, an increase in the area of the site, and an increase in burden on the converted membrane.

In order to solve this problem, aeration means for injecting air into an aerobic tank equipped with a separation membrane is provided to supply particles in the form of powder to the separation tank, A method of reducing the clogging of the separation membrane by colliding with the separation membrane due to the influence of the supplied air has been considered.

However, this method has the effect of reducing the clogging of the separation membrane. However, when the size of the aerobic tank is large, since the particles are in a fine powder form, they are not circulated smoothly in the aerobic tank, (Circulation through recovery), it is difficult to continuously supply a large amount of powdery particles continuously or periodically. In addition, powdered activated carbon is used as the particles to be used. However, the activated carbon has a higher cost than the conventional activated carbon because it is made of natural materials such as wood, lignite, and coal.

On the other hand, after the solid-liquid separation by the separation membrane, the remaining sludge is converted to building materials or biofuels by drying after the water content is lowered through the condensation dehydration facility.

At this time, biofuel has a higher selling price than building materials, but biofuels with a large amount of phosphorus and organic matter are not appreciated due to its low calorific value (energy density) and the industry is not activated accordingly.

As a result, there are a large number of applications for construction-related materials, which are relatively low in selling prices, and the necessity of activating related industries through biofuels using sludge having increased heat due to the inefficient use of biofuels .

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to reduce the clogging of a separation membrane and increase the heat amount of sludge produced through a sewage treatment facility, Processing method.

According to the present invention, there is provided a sewage treatment method for treating sewage, comprising: separating raw sewage sludge from an initial sewage introduced through a primary settling tank; Removing phosphorus release and organic matter from the sewage through the anaerobic tank; Denitrifying the sewage and removing organic matter through an anoxic tank; Performing nitrification of the sewage and oxidation of organic matter through an aerobic tank; Separating surplus sludge through a second settling tank; And a sludge thickening / dehydrating step of converting the sludge transferred from the primary settling tank and the secondary settling tank into a sludge cake through a condensation / dehydration facility, wherein the aeration tank is provided with aeration means for injecting air into the aerobic tank, And a membrane for solid-liquid separation of sewage having passed through the aerobic tank, a fluid circulation device for circulating the sewage supplied to the aerobic tank in the aerobic tank, Compressed activated carbon which is formed of compressed activated carbon having a specific gravity corresponding to the specific gravity of water of 5 mm and which collides with the submerged separation membrane while circulating with sewage in the aerobic tank by the aeration means and the fluid circulation means, Activated carbon supply means for supplying activated carbon to the oxic tank, Is configured to include a trap for collecting the activated carbon activated carbon flakes that can and simultaneously delay clogging of the submerged membrane the sewage treatment, it characterized in that a number of suspended activated carbon can be provided.

At this time, the compressed activated carbon may be manufactured using waste materials generated from agricultural and forestry industries such as rice hull, sawdust, and bark.

A spray tube having a length corresponding to a width of the wall of the oxic tank and being symmetrically positioned in a horizontal direction along both side walls and having a plurality of spray holes for spraying sewage to the center side at regular intervals; A suction pipe which is formed by protruding a predetermined length inward from the vicinity of an upper part of the wall below the water surface of the aerobic tank and which is branched and connected to a spray pipe formed on both sides of the aerobic tank, And a pump for allowing the sewage to flow.

Also, the activated carbon trapping unit may include a collecting frame formed along the wall of the aerobic tank at the sewage surface height of the aerobic tank and having an 'a' shape, and an activated carbon trapped at a predetermined location below the trapping frame, And an activated carbon conveyance pipe for conveying the activated carbon.

The activated carbon collected through the activated carbon collection unit may be transported by the activated carbon conveying pipe and mixed with the sludge transferred from the primary sedimentation tank.

According to the present invention, the granular activated carbon is circulated in the aerobic tank to increase the period of washing the separation membrane, thereby minimizing clogging of the separation membrane, thereby prolonging the service life of the separation membrane.

In addition, it is possible to increase the calorific value of the sludge produced through the sewage treatment facility, thereby increasing the utilization of the biofuel, thereby enabling the revitalization of the related industries and improving the profitability of the operators.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic processing diagram for explaining a sewage treatment facility according to the present invention. FIG.
2 is a conceptual diagram of an aerobic tank according to the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, and specific details for carrying out the present invention will be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic processing diagram for explaining a sewage treatment facility according to the present invention. FIG. 2 is a conceptual diagram of an aerobic tank according to the present invention.

1 and 2, the sewage treatment facility according to the present embodiment includes an anaerobic tank 20, an anoxic tank 30, an oxic tank 40, a secondary settler 30 50, and a sludge concentration and dewatering facility 60. In addition to these, a filtration tank, a disinfection tank, a discharge water passage, a deodorization facility, a sewage sludge storage tank, and the like for filtering sewage through the secondary settler 50 One, this is a generally applicable facility and is omitted for convenience of the city.

The primary settling tank 10 is settled (raw sludge) of the initial floatation of the sewage.

In the anaerobic tank 20, phosphorus emission and organic matter removal are performed in the sewage.

In the anoxic tank 30, denitrification and organic matter removal are performed.

The aerobic tank 40 is maintained in an aerobic state by the aeration means 41, and nitrification and oxidation of organic matter are performed. In addition, an immersion separation membrane module 43 is disposed in the oxic tank 40 to perform solid-liquid separation of sewage.

The secondary settling tank 50 is filled with surplus suspended substances remaining in the sewage water through the aerobic tank 40 (surplus sludge).

The sludge concentration and dewatering facility 60 performs a sludge treatment process for forming a dewatering cake by concentrating and dewatering the sludge (suspended matter) settled in the primary and secondary settling basins 10 and 50.

Specifically, the sewage treatment mechanism by the primary settling tank 10, the anaerobic tank 20, the anoxic tank 30, the oxic tank 40 and the secondary settler 50 described above has a structure that has been used in the conventional sewage treatment apparatus The description of the substance, the reaction formula, and the like in the treatment process will be omitted.

In order to maintain the MLSS of the process constant, the nitrifying nitrate nitrogen in the oxic tank 30 is transferred to the anoxic tank 30 (inner transfer) To the anaerobic tank 20 (outwardly transported). Pipes and pumps for external and internal return are generally applicable configurations and are therefore omitted from FIG. 1 for convenience of illustration.

The present invention will be described mainly with reference to the oxic tank 40 as it has technical features related to the oxic tank 40. [

The aeration means 41 formed in the oxic tank 40 injects air into the oxic tank 40 to make the inside of the oxic tank 40 aerobic and the air bubbles are sucked into the sucker separator module 43 of the oxic tank 40 The clogging of the membrane is minimized by causing it to collide with the membrane.

The activated carbon supplying means 42 supplies granular activated carbon which may collide with the membrane of the submerged membrane module 43 together with the air injected by the aeration means 41.

In this embodiment, compressed activated carbon is used as the granular activated carbon. It has a diameter of about 3 to 5 mm, not a particle close to the powder, and most importantly, it should have a specific gravity similar to that of water. That is, the granular activated carbon has a specific gravity corresponding to the specific gravity of water, and it may be preferable to apply the compressed activated charcoal so as to have a size of 3 to 5 mm.

If the size of the granular activated carbon is smaller than 3 mm, it is difficult to compress and mold the granular activated carbon so as to have a specific gravity corresponding to the specific gravity of water. When the granular activated carbon is 5 mm or more, The efficiency is lowered and the price of activated carbon is increased.

In addition, the granular activated carbon is manufactured in spherical form using waste materials generated from agricultural and forest industries such as rice hull, sawdust, and bark, and can significantly lower the cost of the activated carbon compared to existing activated carbon produced from natural materials .

The amount of the granular activated carbon supplied by the activated carbon supplying means 42 is determined based on the volume of the aerobic tank 40 and the weight of the sludge amount in the entire process. The degree of clogging of the separation membrane or the initial granular activated carbon It can be supplemented depending on the amount of activated carbon to be collected separately.

The aerobic tank 40 may further include a fluid circulation device. The fluid circulating device may include a suction pipe 45a for sucking the sewage inhaled, a spray pipe 45b for spraying sewage, and a pump 45c for sucking and spraying sewage.

The suction pipe 45a is formed below the water surface in the vicinity of the upper side of the wall of the oxic tank 40 for introducing the sewage in the upper part of the oxic tank 40 and is protruded by a predetermined length. And is branched and connected to a spray tube formed on the inner wall of the oxic tank.

The spray tube 45b has a plurality of spray holes formed on the lower side of the wall of the oxic tank 40. The spray tube 45b has a length corresponding to the wall of the oxic tank 40, And a plurality of spray holes for spraying sewage to the center side are formed at regular intervals.

The pump 45c may be configured as a conventional pump that draws sewage through the suction pipe 45a and flows the sewage to be sprayed through the spray pipe 45b.

Such a fluid circulating apparatus is mainly intended for circulating the sewage in the aerobic tank 40 rather than sucking and supplying the granular activated carbon in the sewage, because it may contain a small amount of granular activated carbon in the sewage circulation process, More specifically, the sewage at the center side of the oxic tank 40 has an upward flow by the air supplied from the aeration means 41, and the raised sewage flows toward the wall of the oxic tank 40 . At this time, the sewage is injected toward the center side from the lower side of the side wall of the oxic tank 40, and the sewage in the oxic tank 40 is circulated like convection in the form of riding on the wall of the oxic tank 40 as shown in FIG.

In addition, by allowing the suction pipe 45a to protrude into the oxic tank 40, the suction of granular activated carbon circulating along the wall can be minimized, and the suction and circulation of suspended particulate activated carbon can be prevented have.

In addition, circulation of sewage in the aerobic tank 40 can be more strongly generated through the fluid circulation device, so that the circulation of the granular activated carbon is strengthened, so that the air supply strength of the aeration means 41 can be reduced, A reduction effect can also be derived.

Meanwhile, the aerobic tank 40 may be provided with activated carbon collecting units 46a and 46b. The activated plate collector collects the activated carbon suspended in the water surface of the oxic tank 40 and includes a collection frame 46a formed in the shape of 'b' along the aerobic tank wall having a height similar to the height of the water surface, Is connected to an activated carbon conveyance pipe 46b for moving the collected activated carbon along with a small amount of sewage present in the collecting frame 46a.

The granular activated carbon to be supplied to the aerobic tank 40 of the present invention has a specific gravity similar to that of water in a size of 3 to 5 mm. However, the inside of the aerobic tank 40 Residual debris (material generated from activated carbon such as sculptures, flour, etc.) is generated in the process of circulation, and the residual debris of activated carbon which is generated rises above the water surface and floats. The suspended activated carbon is also drifted along the aerobic tank wall by the circulating flow of sewage. Activated carbon debris 47 collected by the activated carbon collection unit is sent to the sludge concentration and dewatering facility 60 and mixed with sludge before concentration and dewatering, (Energy density) of the fuel is increased.

Hereinafter, the sewage treatment method described above will be described.

The sewage treatment method according to the present invention includes the primary settling tank 10, the anaerobic tank 20, the anoxic tank 30, the oxic tank 40 secondary settling tank 50 and the sludge concentration and dehydrating facility 60 shown in FIG. 1 The aerobic aeration tank 40 is injected with air by the aeration means 41 and the solid-liquid separation is performed by the submerged membrane module 43.

The method of sewage treatment by the primary settling tank 10, the anaerobic tank 20, the anoxic tank 30, and the secondary settling tank 50 can be applied to a conventional sewage treatment facility, and a detailed description thereof will be omitted And only the treatment method by the aerobic tank 40 and the sludge concentration and dewatering facility 60, which is a characteristic feature of the present invention, will be described.

In the wastewater treatment method according to the present invention, granular activated carbon is supplied to the oxic tank 40 together with the air by the aeration means 41. The granular activated carbon is supplied with compressed activated carbon which can be struck against the membrane of the submerged membrane module 43 together with the air injected by the aeration means 41. Specifically, the activated carbon is 3 to 5 mm in size, And has a corresponding weight.

The amount of particulate activated carbon supplied to the oxic tank 40 is determined based on the volume of the aerobic tank 40 and the weight of the sludge amount in the entire process. .

The granular activated carbon supplied into the oxic tank 40 is circulated in the oxic tank 40 by the aeration means 41 and the fluid circulators 45a, 45b and 45c, and is separated from the granular activated carbon during the circulation, Activated carbon debris 47 floated on the water surface is collected in the activated carbon collection units 46a and 46b. The collected activated carbon debris 47 is transferred to the sludge thickening and dehydrating facility 60 through the activated carbon conveying pipe 46b together with some sewage present in the collecting unit and is conveyed from the first settling basin 10 present in the concentrating and dehydrating facility After mixing with the sludge, the sludge cake is mixed with the activated carbon by the dehydration process.

The sludge settled in the secondary settling tank 50 is also transferred to the concentrated dewatering facility 60, and the sludge transferred from the secondary settling tank 50 may partially contain granular activated carbon. This also forms a sludge cake mixed with activated sludge mixed with sludge transferred from the primary sedimentation tank 10 and subjected to a concentration and dehydration process.

In the sewage treatment method as described above, the granular activated carbon is circulated in the aerobic tank to increase the cycle of membrane washing, thereby minimizing clogging of the membrane, thereby extending the service life of the membrane.

In addition, the sludge of the activated sludge collected in the aerobic tank and the sludge of the secondary sludge containing some activated carbon are included in the final concentrated sludge dewatering sludge, thereby increasing the energy density of the sludge cake and increasing the biofuel utilization.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Device and its operating method.

10: primary sedimentation tank 20: anaerobic tank
30: anoxic tank 40: aerobic tank
41: aeration means 42: activated carbon supply means
43: Deposition membrane module
50: Second settling basin 60: Sludge concentration and dehydration facility

Claims (5)

A sewage treatment method for treating sewage,
Separating the raw sludge of the initial sewage introduced through the primary settling tank;
Removing phosphorus release and organic matter from the sewage through the anaerobic tank;
Denitrifying the sewage and removing organic matter through an anoxic tank;
Performing nitrification of the sewage and oxidation of organic matter through an aerobic tank;
Separating surplus sludge through a second settling tank; And
And a sludge concentration and dehydration step of converting the sludge transferred from the primary settling tank and the secondary settling tank into a sludge cake through a concentrating and dehydrating facility,
In the oxic tank,
Aeration means for injecting air into the oxic tank;
An immersion separation membrane module including a membrane for solid-liquid separation of sewage that has passed through the aerobic tank,
A circulation device for circulating sewage supplied to the aerobic tank in the aerobic tank;
The activated carbon which is supplied into the oxic tank and has a specific gravity corresponding to the specific gravity of water of 3 mm to 5 mm is circulated together with the sewage in the aerobic tank by the aeration means and the fluid circulation device, Compressed compressed activated carbon,
Activated carbon supply means for supplying the compressed activated carbon to the oxic tank;
An active carbon collection unit for collecting active carbon debris floating on the surface of the aerobic tank sewage,
The fluid circulating device includes:
A spray tube having a length corresponding to a width of the wall of the oxic tank and being symmetrically positioned in a horizontal direction along both side walls and having a plurality of spray holes for spraying sewage to the center side,
A suction pipe which is formed to protrude inwardly by a predetermined length in the vicinity of an upper portion of a wall below the water surface of the oxic tank and branches and connected to a spray pipe formed on both sides of the oxic tank;
And a pump for allowing the sewage to flow through the suction pipe so as to be injected through the injection pipe. The method according to claim 1,
Wherein the compressed activated carbon is manufactured using waste materials generated from agricultural and forestry industries such as rice hull, sawdust, and bark. delete The method according to claim 1,
The activated carbon collector
An activated carbon conveying pipe formed at a predetermined point below the collecting frame and moving the activated carbon collected together with a small amount of sewage; Wherein the sewage treatment is carried out in the sewage treatment plant. The method according to claim 1,
Wherein the activated carbon collected through the activated carbon collection unit is transported by the activated carbon transport pipe and mixed with the sludge transferred from the primary sedimentation tank.

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