WO2015064933A1

WO2015064933A1 - Method for treating drain-water using sludge aeration in water treatment plant

Info

Publication number: WO2015064933A1
Application number: PCT/KR2014/009731
Authority: WO
Inventors: 백인호; 이성진; 박정욱; 최일경; 변일환
Original assignee: 한국수자원공사
Priority date: 2013-10-30
Filing date: 2014-10-16
Publication date: 2015-05-07
Also published as: KR101416756B1

Abstract

The present invention relates to a method for treating drain-water using sludge aeration in a water treatment plant. The method for treating drain-water using sludge aeration in a water treatment plant comprises the steps of: providing, to a balancing tank, sludge generated while raw water is being treated in a water treatment plant; providing air to the sludge provided to the balancing tank to reduce density of heavy metal and volatile organic material contained in the sludge; concentrating the sludge, aerated in the balancing tank, in a sludge thickener and discharging upper cleaned water; concentrating the sludge, aerated in the balancing tank, in the sludge thickener; and dehydrating the sludge, which was concentrated in the thickener, in a dehydration tank.

Description

Effluent treatment method using water treatment plant sludge aeration

The present invention relates to a wastewater treatment method using the sludge aeration of water treatment plant, in particular, to provide air to the sludge to prevent the increase in the concentration of contaminants, such as heavy metals and volatile organic substances contained in the sludge due to the anaerobic sludge ( The present invention relates to a wastewater treatment method using sludge aeration in a water treatment plant in which sludge is aerated to reduce a concentration of heavy metals and volatile organic substances in the sludge.

In general, a water treatment plant includes a water treatment plant that produces tap water using raw water and a wastewater treatment plant that treats effluent such as sludge generated during the water treatment process.

Normally, the wastewater treatment facility is designed and operated for the purpose of removing the suspended solids contained in the sludge generated during the treatment of raw water, and then discharged after treatment.

Recently, due to the strengthening of water quality regulation of effluents discharged from effluent treatment facilities, the management of pollutants such as manganese and chlorform contained in the effluent is being carried out more strictly. Various facilities are required for removal.

However, in order to remove manganese and chloroform from the effluent, various facility investments with high costs are required for each pollutant, and additional operating personnel are required as well as operating costs of the installed facilities. Have

Therefore, the present invention not only removes heavy metals and volatile organic substances included in the sludge generated during the water treatment process, but also requires less facility investment and operating costs, and minimizes the space for installing the water treatment plant sludge aeration. Provides a method of treating wastewater used.

In one embodiment, the wastewater treatment method using the sludge aeration plant, the sludge generated during the treatment of the raw water in the water purification plant to provide a sludge support; Supplying air to the sludge provided in the sludge support to oxidize and degas heavy metals and volatile organic substances included in the sludge to reduce the concentration; Concentrating the sludge aerated in the sludge support in a sludge thickening tank and discharging the supernatant; Concentrating the sludge aerated in the sludge support in a sludge thickening tank; And dewatering the sludge concentrated in the concentration tank in a dehydration tank.

In the step of reducing the concentration of heavy metals and volatile organic substances contained in the sludge in the wastewater treatment method using a water treatment plant sludge aeration, the heavy metal comprises manganese formed by the oxidation of chlorine provided to the raw water during the water treatment process in the water purification plant. In addition, the volatile organic material includes chlorform formed by reacting with the chlorine provided in the raw water and the organic material contained in the raw water.

In the step of reducing the concentration of heavy metals and volatile organic substances contained in the sludge in the wastewater treatment method using a water treatment plant sludge aeration, the amount of air supplied to the sludge is preferably 270 mL / min to 330 mL / min per 20 [L] of sludge. 300 mL / min.

In the step of reducing the concentration of heavy metals and volatile organic substances included in the sludge in the wastewater treatment method using a water treatment plant sludge aeration, the air is supplied to the sludge for 12 to 24 hours.

In the effluent treatment method using the water treatment plant sludge aeration, the sludge is re-dissolved in the concentration facility to increase the concentration of heavy metals and volatile organic substances, so that the hydrogen ion index (S) in the sludge to further reduce the concentration of manganese contained in the sludge. providing a pH adjusting agent to adjust the pH).

In the wastewater treatment method using a water treatment plant sludge aeration, the hydrogen ion index (pH) of the sludge provided with the pH adjusting agent is pH 8 to pH 10.

According to the present invention, not only can the heavy metal and volatile organic substances contained in the sludge generated during the water treatment process be easily removed at the same time, but also the sludge settling property is improved, and facility investment cost and operation cost are low, It has the effect of minimizing the space for installation.

1 is a flowchart illustrating a wastewater treatment method using sludge aeration water treatment plant according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a wastewater treatment facility for implementing the wastewater treatment method using the water treatment plant sludge aeration of FIG. 1.

3 is a graph showing the sludge volume change according to the amount of air by the wastewater treatment method using the water treatment plant sludge aeration according to FIG.

4 is a graph showing a change in manganese concentration according to the amount of air in FIG.

5 is a graph showing the volume change of the sludge according to the air supply time in the optimized air amount.

FIG. 6 is a graph illustrating symbol manganese concentration according to the air supply time of FIG. 5.

FIG. 7 is a graph showing the concentration of supernatant chloroform according to the air supply time of FIG. 5.

FIG. 8 is a graph showing symbolic manganese concentration according to air supply and pH adjustment of FIG. 5.

In the following description, only parts necessary for understanding the embodiments of the present invention will be described, it should be noted that the description of other parts will be omitted so as not to distract from the gist of the present invention.

The terms or words used in the specification and claims described below should not be construed as being limited to the ordinary or dictionary meanings, and the inventors are appropriate to the concept of terms in order to explain their invention in the best way. It should be interpreted as meanings and concepts in accordance with the technical spirit of the present invention based on the principle that it can be defined. Therefore, the embodiments described in the present specification and the configuration shown in the drawings are only preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, and various equivalents may be substituted for them at the time of the present application. It should be understood that there may be variations and variations.

1 is a flowchart illustrating a wastewater treatment method using sludge aeration water treatment plant according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a wastewater treatment plant for implementing the wastewater treatment method using the wastewater treatment plant sludge aeration shown in FIG. 1.

1 and 2, a large amount of sludge 10 generated in the process of purifying raw water by the purified water treatment plant 100 in the water purification plant 600 is discharged to the sludge support 100 of the wastewater treatment facility 500. Is provided. (Step S10)

The sludge provided as the slurry support 100 contains a large amount of organic matter, earth and sand, a plurality of inorganic materials, heavy metals such as manganese and chlorform, which is a volatile organic material.

The manganese concentration contained in the sludge 10 increases in proportion to the residence time of the sludge 10 provided as the sludge support 100, which does not supply oxygen to the sludge 10 so that anaerobicization of the sludge 10 proceeds. This is because the manganese oxide contained in the sludge 10 is reduced to the form of dissolved manganese.

In addition, the concentration of chlorform, which is a volatile organic material included in the sludge 10, is increased in proportion to the residence time of the sludge 10 provided as the sludge support 100.

In conclusion, the concentrations of manganese and chlorform contained in the sludge 10 provided as the sludge support 100 are in proportion to the time of staying in the anaerobic state generated by not supplying oxygen to the sludge 10 in common.

Referring back to FIG. 1, in order to prevent anaerobicization of the sludge 10 provided in the sludge support 200 and to aeration of the sludge 10 to reduce the concentration of manganese and chlorform contained in the sludge 10. Air containing oxygen is supplied to the sludge 10 provided in the slurry support 200. (Step S20)

In order to supply air containing oxygen to the sludge 10 provided in the slurry support 200, the aeration unit 250 is installed in the slurry support 200 as shown in FIG. 2.

The aeration unit 250 supplies air containing oxygen to the sludge 10 provided as the sludge support 200 to aerobic the sludge 10 while preventing the anaerobicization of the sludge 10 to the sludge 10. To reduce the concentration of manganese and chlorform contained below the reference value, the sedimentation of the sludge 10 can also be improved.

The aeration unit 250 shown in FIG. 2 is disposed in the interior of the sludge support 200, and the aeration unit 250 includes, for example, a blower 220 and a sludge 10 for blowing air containing oxygen. It may include a blower pipe 240 for injecting air containing oxygen into the.

Two blowers 220 are connected to each other including a spare device, and the blower pipe 240 is connected to the discharge port of the blower 220. Each blower tube 240 is provided with acid substrates 245 for generating bubbles.

As the sludge 10 is aerated as air containing oxygen is supplied to the sludge 10 provided into the sludge support 200 by the blower 220, the blower tube 240, and the acid substrate 245. It is possible to greatly reduce the concentration of manganese by preventing the reduction of manganese oxide contained in the sludge 10, and greatly reduce the concentration of chlorform, a volatile organic substance, through degassing by supplied air, and through sludge equalization Reduction in porosity can also improve sedimentation.

In one embodiment of the present invention, by supplying air containing oxygen to the sludge 10 of the sludge support 200 for about 12 hours can reduce the concentration of manganese contained in the sludge 10 by about 40% have.

As air containing oxygen is supplied to the sludge 10 of the sludge support 200 for about 12 hours, the concentration of chlorform contained in the sludge 10 is reduced by about 60%, and the sludge of the sludge support 200 is reduced. By supplying the air containing oxygen to (10) for about 12 hours, the total volume of the sludge 10 can be reduced by about 35%.

Hereinafter, the operation and effect generated when air is supplied to the sludge 10 provided as the sludge support 200 according to an embodiment of the present invention will be described in more detail through an experimental graph.

3 is a graph showing the sludge volume change in the wastewater treatment method using the sludge aeration plant according to FIG. 4 is a graph showing a change in manganese concentration according to the air supply amount in FIG.

Referring to FIGS. 3 and 4, in order to select an optimum air amount supply condition (aeration amount, aeration time), four sludges 10 generated in a water treatment plant in a laboratory were sampled at about 20 [L].

In order to select the optimum air flow conditions, the laboratory sampled four sludges 10 each for about 24 hours with aeration (no air), 300 mL / min, 600 mL / min and 900 mL / min of air volume, respectively. Air was supplied (aerated) and then the four sludges 10 sampled were concentrated (sedimented) for about 240 hours.

Referring to the graph of FIG. 3, in terms of the volume of the sludge 10, when the air is supplied for about 24 hours at an air volume of about 300 L / min, and then concentrated for about 24 hours (line A of FIG. 3), the sludge 10 The volume of was about 540 mL / L and the volume of the aeration sludge 10 was about 760 mL / L. At a volume of air of 300 L / min, the volume of the sludge 10 was reduced by 29% compared to the volume of the aeration sludge 10. .

Referring to Figure 4, when measuring the manganese concentration of the symbol water (clear water in the upper part of the sludge after the sludge settled), the manganese concentration of the non-aeration sludge (10) is initially about 6 mg / L but the non-aeration sludge (10 ), Concentration of manganese rose sharply from about 6 mg / L to about 10 mg / L.

This rapid increase in manganese concentration is due to the re-elution of particulate manganese into the sludge 10 by anaerobic sludge 10 during the concentration of non-aeration sludge 10.

Comparing the manganese concentration measured in the symbolic water of the non-aeration sludge in Figure 4 and the manganese concentration in the symbolic water of the sludge 10 provided air amounts of about 300 mL / min, about 600 mL / min and about 900 mL / min, The manganese concentration of the aeration sludge 10 is about 8 mg / L, while the manganese concentration of the sludge 10 which provides the air volumes of about 300 mL / min, about 600 mL / min and about 900 mL / min is about 3.12 mg / L. Compared to aeration sludge (10), the reduction was about 61%.

Referring again to FIG. 3, when air is supplied to the sludge 10 at an air volume of about 900 mL / min, the volume of the sludge 10 is reduced by about 12% to provide air to the sludge 10 at an air volume of about 300 mL / min. The volume reduction efficiency of the sludge 10 was lower than when provided.

Overall, as the amount of air provided to the sludge 10 increases, the volume reduction efficiency of the sludge 10 and the decrease of manganese concentration are not proportional, but about 300 mL / min per 20 [L] of the sludge 10. Providing air to the sludge 10 in the amount of air is the best for reducing the volume of the sludge 10, reducing the manganese concentration and the removal of chloroform, preferably of about 300 mL / min of the amount of air provided to the sludge 10 The volume reduction efficiency of the sludge 10, the manganese concentration reduction and the removal efficiency of chloroform are also excellent in the range of 270 mL / min to 330 mL / min, which is an error range of 10%.

When the optimal amount of air is set, it is very advantageous in terms of energy saving because it is not necessary to operate the blower that provides air to the sludge 10 excessively.

FIG. 5 is a graph showing the volume change of the sludge according to the aeration time in the sludge support 200 in an optimized air volume.

FIG. 6 is a graph illustrating symbol manganese concentration according to the air supply of FIG. 5.

7 is a graph showing the concentration of supernatant chloroform according to the air supply of FIG.

3 and 4, when the optimum air volume of about 300mL / min is set, the sludge according to the air supply time at about 300mL / min (20L of sludge) in order to find the optimal air supply time based on the optimal air volume Sedimentation, symbolic manganese concentration and chloroform concentration were measured in FIGS. 5, 6, and 7.

5, 6, and 7, the manganese concentration of the sludge 10 and the symbol water of the sludge 10 and the symbol of the sludge 10 when air is supplied for about 12 hours to about 24 hours. The rate of decrease in concentration of water chloroform was particularly good.

When air was supplied to the sludge 10 for about 12 hours at an air volume of about 300 mL / min, the sludge settling volume was reduced by about 35% compared to the settling volume of the non-aeration sludge 10, which was about 300 mL / min. This is because by providing air to the), the voids are reduced according to the homogenization of floc particles of the sludge 10, thereby improving the settling property.

In FIG. 6, bar graph A represents manganese concentration of symbol water during non-aeration, bar graph B represents manganese concentration of symbol water by enrichment time after supplying air for 2 hours, and graph C supplying air for 6 hours. After the manganese concentration of symbol water by enrichment time, graph D shows the manganese concentration of symbol water by enrichment time after supplying air for 12 hours, and graph E shows the manganese concentration of symbol water by enrichment time after supplying air for 24 hours Indicates.

In FIG. 6, when the sludge 10 was settled for about 24 hours after supplying air to the sludge 10 for different times, the manganese concentration of the symbol water in the graph A corresponding to non-aeration was about 1.65 mg / L. Manganese concentration of symbolic water in the graph D, which supplied air to the sludge 10 for about 12 hours, was about 0.98 mg / L, and manganese concentration of the symbolic water of the sludge 10 supplied with air for 12 hours was non-aeration sludge (10). ), About 40% reduction.

In FIG. 7, the bar graph A shows the concentration of the symbolic chloroform during non-aeration, the graph B shows the concentration of the symbolic chloroform after 2 hours of aeration, and the graph C shows the concentration of the symbolic chloroform after 6 hours of aeration, and the graph D. Is the concentration of symbolic chloroform at 12 hours aeration, and graph E represents the concentration of symbolic chloroform at 24 hours aeration. Graphs A to D are concentrations measured after 24 hours of precipitation after different time aerations.

The concentration of chloroform in graph A corresponding to non-aeration is 0.175 mg / L, whereas the concentration of chloroform in the symbolic water of graph D is about 0.067 mg / L for 12 hours when air is supplied to the sludge 10 for 12 hours. The concentration of the supernatant chloroform of the supplied sludge 10 was reduced by about 60% compared to the non-aeration sludge 10.

Based on the results of FIGS. 5, 6, and 7, the operating condition of the aeration unit 250 was about 300 mL / min (per 20 [L] of sludge) considering the power ratio, and the air was provided based on the optimum amount of air. The time is preferably about 12 hours to about 24 hours.

Based on the graphs of FIGS. 3 to 7, similar results can be realized by performing aeration in the laboratory as well as in the wandering support 200 shown in FIG. 2, and the concentration of manganese is 40% and the concentration of chlorform It can also reduce about 60% and the sludge 10 sedimentation rate can also be reduced by 35%.

In one embodiment of the present invention, by installing the aeration unit 250 in the sludge support 200 in order to aerobic the sludge provided in the sludge support 200, the air in the sludge 10 at the optimum amount of air for an optimal time When supplied, the concentration of volatile organic substances such as heavy metals and chloroform, including manganese contained in the sludge 10, as well as the sludge settling properties can be improved.

On the other hand, even if air is supplied to the sludge 10 provided in the sludge 200, manganese is re-dissolved into the sludge during long-term stay in the summer, the manganese concentration of the symbol water increases. In order to solve this problem, the sludge support 200 is sludged with a pH adjusting chemical provided by the pH adjusting unit 260 to adjust the hydrogen ion index (pH) of the sludge 10 provided as the sludge support 200. It may be provided in (10), the pH adjusting agent may be provided to the sludge 10 after the step of providing the sludge 10 to the slurry support 200.

8 is a graph showing the manganese concentration of symbol water by sedimentation time when the pH of the sludge 10 provided in the sludge 200 is adjusted.

In FIG. 8, graph A represents manganese concentration of symbol water by sedimentation time during non-aeration, and graph B shows manganese concentration of sedimentation time by sedimentation time after 12 hours of aeration with sludge itself without pH adjustment at 300mL / min.

Graph C of Figure 8 shows the manganese concentration of the symbolic water by sedimentation time after 12 hours aeration with the aeration amount after adjusting to pH 8, graph D shows the manganese concentration of sedimenting time by the sedimentation time after aeration with the aeration amount after adjusting to pH 9 The graph E shows the manganese concentration of the symbolic water according to the settling time after 12 hours of aeration after adjusting to pH 10.

In FIG. 8, graph B shows that the symbolic manganese concentration sharply increases after 48 hours of sedimentation despite the sludge aeration, and the symbolic manganese concentration of 24 hours after sedimentation is 3.77mg / L after 144 hours of sedimentation. This shows a sharp increase of 4.5 times.

However, referring to graph C, graph D, and graph E with pH adjustment, it is possible to prevent the sudden increase of manganese concentration like graph B, and considering that the current emission limit is pH 8.5 or lower, After settling time, the symbolic manganese concentration is 0.39mg / L, and 1.37mg / L after 144 hours of sedimentation can ensure the stability of water quality.

In graph A, 60% of the symbolic manganese concentration can be removed after 24 hours of sedimentation of the aeration sludge 10, and when the pH is not adjusted, the manganese removal rate of 40% can be improved to 60%.

In one embodiment of the present invention, the hydrogen ion index (ph) of the sludge 10 provided in the slurry support 200 is from about pH6.5 to about pH7.5, by the pH control unit 260 When (ph) is adjusted to about pH8 to pH10, manganese concentration can be reduced to 60% or more.

Referring back to FIGS. 1 and 2, the sludge 10 provided with air from about 12 hours to about 24 hours in the sludge support 200 is provided to the sludge thickener 300 connected in series with the sludge support 200. And concentrated. (Step S30)

The symbol water generated after condensing the sludge aerated in the sludge support 200 in the sludge thickening tank 300 is discharged, wherein the discharged water is the concentration of manganese and chlorform defined by the aeration in the sludge support 200 Satisfies the concentration.

Subsequently, the supernatant is discharged and the concentrated sludge remaining in the sludge thickening tank 300 is dewatered in the dewatering tank 400 disposed adjacent to the sludge thickening tank 300. (Step S40)

As described in detail above, it is possible to easily remove heavy metals and volatile organic substances contained in the sludge generated during the raw water treatment, and improve sludge concentration, and require less facility investment and operation costs. It has the effect of minimizing the space for installing the facility.

On the other hand, the embodiments disclosed in the drawings are merely presented specific examples to aid understanding, and are not intended to limit the scope of the invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

The present invention provides air to the sludge of the water purification plant to reduce the concentration of manganese contained in the sludge and to provide a pH adjusting agent to the sludge with reduced manganese concentration does not increase the concentration of manganese contained in the sludge over time It can be used for the treatment of effluent from the water purification plant.

Claims

Providing sludge containing organics, soils, minerals, manganese and chloroform as a slurry;

Supplying air to the sludge provided in the sludge support to reduce the concentrations of manganese and chlorform contained in the sludge;

Concentrating the sludge aerated in the sludge support in a sludge thickening tank; And

Dehydrating the sludge concentrated in the concentration tank in a dehydration tank,

After providing the sludge to the sludge support, the manganese whose concentration has been reduced by the air is anaerobic over time and re-eluted into the sludge to prevent the concentration of the manganese in the sludge from increasing. A method of treating effluent water using a sludge aeration plant comprising the step of providing a pH adjusting agent for adjusting the hydrogen ion index (pH) to the sludge.
The method of claim 1,

In the step of reducing the concentration of the manganese and the chloroform contained in the sludge,

The amount of air provided to the sludge is 270 mL / min to 330 mL / min per 20 [L] of wastewater treatment wastewater treatment method using a sludge aeration plant.
The method of claim 2,

In the step of reducing the concentration of the manganese and the chloroform contained in the sludge,

The sludge wastewater treatment method using a water treatment plant sludge aeration is supplied to the air for 12 to 24 hours.
The method of claim 1,

Hydrogen ion index (ph) of the sludge is pH 6.5 to pH7.5, and the hydrogen ion index (pH) of the sludge provided with the pH control agent is pH 8 to pH 10 Wastewater treatment method using a sludge aeration plant.