KR100720008B1 - Advanced treatment system of wastewater and its method - Google Patents

Abstract

Advanced wastewater treatment apparatus and method according to the present invention includes a biological reaction tank into which wastewater flows; A concentrated dehydrator for drawing excess sludge generated in the biological reaction tank and directly dewatering the treated sludge; A settling tank receiving the wastewater introduced from the biological reaction tank to discharge the supernatant and return the precipitated sludge solution; A sludge anaerobic tank provided between the settling tank and the biological reaction tank and storing the sludge liquid returned from the settling tank and entering the biological reaction tank through anaerobic conditions; It is configured to include an organic carbon supply unit for introducing a predetermined amount of wastewater flowing into the biological reaction tank into the sludge anaerobic tank, by supplying a certain amount of organic matter by using wastewater, and over-intake of phosphorus in aerobic conditions to re-release phosphorus (Secondary release) prevents the phenomenon can be maximized the effect.

Description

Advanced treatment system of wastewater and its method

1 is a block diagram showing a conventional wastewater advanced treatment sequence,

2 is a configuration diagram showing a conventional wastewater wastewater treatment apparatus,

3 is a block diagram showing an advanced wastewater treatment process according to the present invention;

4 is a block diagram showing an advanced wastewater treatment system according to the present invention,

5 is a graph for explaining the principle of biological removal of the present invention.

<Explanation of symbols for the main parts of the drawings>

51: sedimentation tank 53: inflow pump tank

54: wastewater transfer line 55: biological reactor

56: blower blower 57: underwater aeration

60: sedimentation tank 62: discharge tank

65: concentrated dehydrator 67: sludge drawing pump

70: sludge anaerobic tank 72: outlet

75: return sludge pump 80: organic carbon supply unit

81: organic matter supply line 83: supply control valve

The present invention relates to an advanced wastewater treatment apparatus and method, in particular, having a separate sludge anaerobic tank in a bioreactor and allowing a portion of the wastewater to be injected into the sludge anaerobic tank to maximize phosphorus removal efficiency. An apparatus and method are provided.

The present applicant has applied for a utility model registration application for the design of activated sludge treatment system of sewage (Registration No. 20-289790).

The registration design is applied to the Aerated Solids Retention Time (ASRT) theory in order to efficiently remove organic matter and nitrogen phosphorus by coping with load fluctuations of daily, weekly and seasonal, which are important problems in sewage treatment plants. It is devised to do.

Such a registration scheme will be described with reference to the drawings as follows.

1 is a block diagram showing the basic configuration of the registration scheme, Figure 2 is a block diagram showing a processing system of the registration scheme.

The treatment system shown here is a system for drawing and treating excess sludge directly in a single reactor 15, and draws activated sludge liquid directly in a single reactor 15 according to the inflow load. As a result, when the inflow load is largely changed, SRT (Solids Retention Time) is changed, but by controlling the actual ratio of the aerobic treatment time to the anaerobic treatment time according to the inflow load, the SRT under the aerobic condition is controlled to be constant. have.

To this end, the treatment system is provided with a flow plate concentrated dehydrator 25 capable of directly dehydrating activated sludge without concentration, and an aquarator 17 capable of freely adjusting the anaerobic and aerobic time ratios.

Such a treatment system is a process of treating nitrogen and phosphorus in the single reaction tank 15, and supplies waste water introduced into the sedimentation tank 11 to the single reaction tank 15 in the inlet pump tank 13, a single reaction tank The waste water supplied to (15) is anaerobic and aerobic treated in accordance with the operating conditions of the aeration blower 16 and the underwater air blower 17.

Subsequently, the excess sludge in the single reaction tank 15 is directly transferred to the concentrated dehydrator 25 by the operation of the sludge drawing pump 27 and dewatered, and the wastewater discharged from the single reaction tank 15 is transferred to the final settling tank 20. It is configured to discharge through the discharge tank 22 after being introduced.

And the sludge liquid including the sludge settled in the final settling tank 20 is returned to the single reaction tank 15 by the operation of the return sludge pump 30.

However, the wastewater treatment system of the above-described registration design has a problem in that the phosphorus is removed more effectively in the wastewater because phosphorus is removed while operating alternately under anaerobic or aerobic conditions in a single reactor.

That is, the above-described registration scheme uses an ACS method, that is, an intermittent aeration method, and has a process of dewatering sludge directly in a single reactor by adjusting it with an ASRT, but the theoretical removal of phosphorus from such a treatment process is an aerobic time zone microorganism. Ingestion is caused by excessive intake, the ACS method has a problem that the anaerobic period is rather short, so that phosphorus removal cannot be effectively performed.

The present invention has been made to solve the above problems, by storing the sludge liquid returned from the final sedimentation tank in a sludge anaerobic tank configured separately from the biological reaction tank and configured to inject a small amount of wastewater into the sludge anaerobic tank to accumulate microorganisms It is an object of the present invention to provide a wastewater wastewater treatment apparatus and method that can induce excessive intake of phosphorus from aerobic state stably by ingesting enough of the organic matter, thereby maximizing the treatment effect at an economical cost.

The wastewater advanced treatment apparatus according to the present invention for realizing the above object includes a biological reaction tank into which wastewater flows; An underwater aeration unit provided in the biological reactor to selectively perform anaerobic and aerobic operation; A concentrated dehydrator for drawing excess sludge generated in the biological reaction tank and directly dewatering the treated sludge; A settling tank receiving the wastewater introduced from the biological reaction tank to discharge the supernatant and return the precipitated sludge solution; A sludge anaerobic tank provided between the settling tank and the biological reaction tank and storing the sludge liquid returned from the settling tank and entering the biological reaction tank through anaerobic conditions; Characterized in that it comprises an organic carbon supply for allowing a predetermined amount of wastewater flowing into the biological reactor into the sludge anaerobic tank.

Here, the organic carbon supply unit is preferably configured to supply the wastewater into the sludge anaerobic tank from the inflow pump tank for supplying the wastewater to the biological reaction tank.

In addition, the amount of waste water injected through the organic carbon supply unit is preferably about 10 to 20% of the low amount of the sludge anaerobic tank.

The wastewater advanced treatment method according to the present invention for realizing the above object comprises the steps of treating the wastewater introduced into the reaction tank while selectively performing anaerobic stirring and aerobic stirring; Drawing out excess sludge generated in the reactor to dehydrate the treatment; Discharging the supernatant in the wastewater passed through the reaction tank, and returning the sludge liquid deposited at the bottom to the sludge anaerobic tank; Improving a phosphorus removing microorganism by introducing a portion of wastewater before entering the reactor into the sludge anaerobic tank and storing the returned sludge liquid in the sludge anaerobic tank in an anaerobic manner; Including the sludge in excess of phosphorus from the improved microorganism by introducing the wastewater overflowed from the sludge anaerobic tank back to the reactor.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

Figure 3 is a block diagram showing the high level of wastewater treatment according to the present invention, Figure 4 is a block diagram showing a high degree of wastewater treatment apparatus according to the present invention.

Referring to FIG. 3, the wastewater advanced treatment sequence according to the present invention is introduced into the bioreactor 55 from the sedimentation tank 51 and the inflow pump tank 53, and the sewage water that has passed through the bioreactor 55 is settling tank 60. The supernatant is discharged to the outside through the discharge tank 62, and the sludge liquid containing the sludge is returned to the sludge anaerobic tank 70, and then flowed back into the biological reaction tank 55 and treated, while the biological reaction tank 55 The excess sludge produced in the) is discharged to the concentrated dehydrator 65 and processed.

The wastewater advanced treatment apparatus of the present invention for implementing such a treatment sequence will be described in detail with reference to FIG. 4.

The wastewater advanced treatment apparatus of the present invention includes a sedimentation tank 51 and an inflow pump tank 53 into which wastewater flows in, a biological reaction tank 55 in which the wastewater supplied from the inflow pump tank 53 is treated, and the biological It is provided in the reaction tank 55, the underwater aeration device 57 for selectively performing anaerobic and aerobic agitation, a concentrated dehydrator 65 for drawing and treating the excess sludge generated in the biological reaction tank 55 to directly dewatering, and A sedimentation tank 60 for receiving the wastewater from the biological reaction tank 55 and discharging the supernatant and returning the liquid such as sludge, and provided between the precipitation tank 60 and the biological reaction tank 55 and settling the tank 60. Sludge anaerobic tank 70 for storing the sludge conveyed in and then put into the biological reaction tank 55 by anaerobic treatment.

In particular, the present invention is composed of an organic carbon supply unit 80 for introducing a predetermined amount of wastewater flowing into the biological reaction tank 55 into the sludge anaerobic tank (70).

The major components constituting such an apparatus of the present invention will be described in detail as follows.

First, the sedimentation tank 51 filters large foreign matters contained in the inflow sewage through the screen, and the inflow pump tank 53 supplies the wastewater introduced into the biological reaction tank 55.

Next, the biological reactor 55 is configured to treat the wastewater by adjusting the anaerobic and aerobic time ratios according to the inflow load by using the underwater aeration 57 and the aeration blower 56.

Next, the concentrated dehydrator 65 is configured to draw and dehydrate the activated sludge liquid directly through the sludge drawing pump 67 in the biological reaction tank 55, it is composed of a fluidized plate concentrated dehydrator (65). Since its specific configuration is well-known technology, a detailed description thereof will be omitted.

Next, the sedimentation tank 60 is provided with a sludge collector 61 which is rotationally driven therein, and the supernatant of the sludge precipitated is discharged to the discharge tank 62 and discharged to a stream or the like, and filtered by the sludge collector 61. Sludge liquid containing sludge is sent to the sludge anaerobic tank 70 via a conveying line 74.

Next, the sludge anaerobic tank 70 is a component part installed to increase phosphorus removal efficiency under anaerobic conditions, and is integrally provided in the biological reaction tank 55, and is divided into partition walls 71. An upper portion of the partition wall 71 is provided with an outlet 72 so that the sewage wastewater overflowed from the sludge anaerobic tank 70 is transferred to the bioreactor 55.

In addition, a stirrer 73 is provided inside the sludge anaerobic tank 70 so as not to precipitate sewage water introduced into the anaerobic tank.

And between the settling tank 60 and the sludge anaerobic tank 70 is provided with a conveying sludge pump 75 is configured to forcibly transport the wastewater containing sludge.

In this embodiment, the sludge anaerobic tank 70 is illustrated as being integrally formed in the biological reaction tank 55, but is not limited to this configuration that can be anaerobic treatment in the state of storing the sludge returned from the settling tank (60). The rear surface may be configured to be separated from the biological reaction tank 55.

Next, the organic carbon supply unit 80 is a part for supplying an organic carbon source to the sludge anaerobic tank 70, without using a separate organic carbon supply means, so that the organic carbon source included in the waste water can be used to the inflow pump tank It is configured to use a certain amount of wastewater flowing into the biological reactor (55) at (53).

That is, referring to FIG. 4, a wastewater supply line 54 is provided between the inflow pump tank 53 and the biological reaction tank 55 so as to supply the wastewater. The organic carbon supply unit 80 is the wastewater. It is composed of an organic material supply line 81 branched from the supply line 54 and connected to the sludge anaerobic tank (70).

Here, the organic material supply line 81 is preferably provided with a supply control valve 83 to adjust the amount of the organic carbon source, that is, the amount of sewage water flowing into the sludge anaerobic tank (70).

At this time, the amount of wastewater injected into the sludge anaerobic tank 70 is preferably about 10 to 20% of the total amount of storage of the sludge anaerobic tank 70.

On the other hand, the organic material supply line 81 is illustrated as a branched structure from the sewage waste water supply line 54, but according to the implementation conditions are directly connected to the sludge anaerobic tank 70 in the inlet pump tank 53 It is also configured to supply a small amount of wastewater, or it is also possible to supply external wastewater to the sludge anaerobic tank (70).

Referring to the wastewater wastewater treatment method using the wastewater wastewater treatment apparatus according to the present invention configured as described above are as follows.

First, the sewage water introduced into the sedimentation tank 51 is introduced into the biological reaction tank 55 through the inflow pump tank 53, and the wastewater introduced into the biological reaction tank 55 is an underwater aeration device 57 and an aeration blower ( 56), the sludge is drawn and treated while selectively performing anaerobic and aerobic agitation.

Next, the excess sludge generated in the bioreactor 55 is directly drawn out using a sludge drawing pump 67 to dehydrate the concentrated dehydrator 65, while passing through the bioreactor 55 in the settling tank 60. The supernatant in the wastewater is discharged, and the sludge liquid settled in the lower portion is returned to the sludge anaerobic tank 70 by the conveying sludge pump 75.

Next, the wastewater containing sludge conveyed in the sludge anaerobic tank 70 is stored in an anaerobic manner, and a predetermined amount of wastewater is introduced from the inflow pump tank 53, so that an organic carbon source is supplied so that the phosphorus-removing microorganisms excess phosphorus. After the improvement step for ingestion is carried out, it is again introduced into the bioreactor 55 to efficiently remove phosphorus. The treatment of the wastewater is carried out by repeating these steps.

Here, the principle of efficiently removing phosphorus while supplying the organic carbon source to the sludge anaerobic tank 70 as well as using the sludge anaerobic tank 70 will be described below.

5 is a graph for explaining the principle of biological removal of the present invention.

In general, there is a fundamental difference in principle between the biological nitrogen removal method and the biological phosphorus removal method, and it is difficult to efficiently remove nitrogen and phosphorus simultaneously in either process.

The principle difference is that biological nitrogen removal requires a longer anaerobic operation time in order to keep the nitrogen removal microorganisms with slow growth rate, whereas biological removal requires reverse aerobic operation to ingest excess phosphorus into activated sludge. It is necessary to control the operation to increase the time and increase the amount of excess sludge produced. Therefore, if the exhalation operation time is increased in order to increase the phosphorus removal efficiency, since the nitrogen removal efficiency is lowered on the contrary, a system for increasing the phosphorus removal efficiency without reducing the nitrogen removal efficiency is required.

In the present invention, the release of phosphorus by the activated sludge microorganism and the excessive intake of metabolism as shown in Figure 5 is used, the anaerobic conditions as in the section "A" of Figure 5 in the sludge anaerobic tank 70, which is a main feature of the present invention To secure additionally, the wastewater containing phosphorus elutes phosphorus in the sludge in the course of passing through the sludge anaerobic tank 70, and the phosphorus removal efficiency by ingesting excessive phosphorus in the biological reaction tank 55 that can perform aerobic operation Can be maximized.

That is, according to recent research results of each country, as shown in FIG. 5, a luxury uptake in which phosphorus is released in an anaerobic state and excess phosphorus is ingested in an aerobic state is obtained.

Inchuk enemy microorganism that is, PAO microorganisms (Acinetobacter) of certain bacteria is a short fatty acid (Fatty acid) for PHB (Poly hydroxy butyrate, such as acetate under anaerobic conditions, such as sludge anaerobic tank 70 of the present invention, (C ₄ H ₆ O ₂ ) _n ) Accumulate in the body, and the energy required is obtained by decomposing poly-phosphate (Poly-P; poly-phosphate) into ortho-P (ortho-phosphate). Eliminate microbial growth.

In particular, the sludge returned from the settling tank 60 into the sludge anaerobic tank 70 contains nitrate nitrogen, wherein the nitrate (nitrogen) microorganism reacts the carbon source in the sludge anaerobic tank 70 faster than the phosphorus intake microorganism. Since it can be consumed, sufficient organic matter (carbon source) must be supplied to induce high phosphorus release to be passed to the bioreactor 55, and then excessive intake of phosphorus in aerobic state can induce high phosphorus treatment efficiency.

That is, when the organic matter (carbon source) is insufficient in the sludge anaerobic tank 70, PAO microorganisms release a small amount of phosphorus. At this time, the phosphorus excess intake due to the growth of microorganisms under aerobic conditions decreases the efficiency of phosphorus treatment. Therefore, by injecting a small amount of wastewater into the sludge anaerobic tank 70 using the organic carbon supply unit 80, PAO microorganisms ortho-P ortho-P in the sludge anaerobic tank 70 It is released in the form of) and accumulates in the body in the form of PHB using the organic carbon source in the injected wastewater.

PAO microorganisms maintained in the dominant species state in the sludge anaerobic tank 70 is transferred to the biological reaction tank 55, and then decomposed organic phosphate (PHB) accumulated in the aerobic state by using the energy generated by using the energy generated while growing Luxury uptake, ie, over-ingestion, re-synthesized with Poly-P, and the phosphorus-derived sludge containing over-ingested microorganisms is separated directly to the concentrated dehydrator 65. It will be able to maximize the removal.

As a result, the present invention, as described above, the sludge anaerobic tank 70 is configured to ensure sufficient anaerobic conditions separately from the biological reaction tank 55, and the organic carbon source is injected into the sludge anaerobic tank 70 using wastewater. Therefore, even under conditions that do not lengthen the exhalation operation time, the microorganisms induce excessive intake of phosphorus during the exhalation time, and the concentrated dehydrator 65 is used in such a state that the microorganisms ingest a large amount of phosphorus in a high density. By removing the sludge produced in the bioreactor 55 directly to remove it can increase the phosphorus removal efficiency.

The wastewater advanced treatment apparatus and method according to the present invention constructed and operated as described above is configured to store sludge returned from the settling tank in a sludge anaerobic tank and then to be introduced into a bioreactor, without introducing chemicals or the like by a simple structural change. While maintaining the nitrogen removal function sufficiently, it is possible to increase the phosphorus removal efficiency as much as possible, there is an advantage that can perform a high efficiency nitrogen and phosphorus treatment function.

In addition, the present invention is configured to supply the organic carbon source by supplying the wastewater to the sludge anaerobic tank, so that even in the absence of a separate external carbon source to supply a certain amount of organic matter using wastewater to ingest excessive phosphorus in aerobic conditions In this way, the secondary release phenomenon of phosphorus can be prevented, so that the phosphorus removal efficiency can be further improved. Accordingly, there is an advantage of maximizing the economical and advanced treatment effect by simple structure change.

Claims (5)

A biological reaction tank into which wastewater is introduced; An underwater aeration unit provided in the biological reactor to selectively perform anaerobic and aerobic operation; A concentrated dehydrator for drawing excess sludge generated in the biological reaction tank and directly dewatering the treated sludge; A settling tank receiving the wastewater introduced from the biological reaction tank to discharge the supernatant and return the precipitated sludge solution; A sludge anaerobic tank provided between the settling tank and the biological reaction tank and storing the sludge liquid returned from the settling tank and entering the biological reaction tank through anaerobic conditions; Advanced wastewater treatment apparatus comprising an organic carbon supply unit for introducing a predetermined amount of wastewater introduced into the biological reaction tank into the sludge anaerobic tank. The method according to claim 1, And the organic carbon supply unit is configured to supply wastewater into the sludge anaerobic tank from an inflow pump tank for supplying wastewater to the biological reaction tank. The method according to claim 2, And the organic carbon supply unit includes an organic material supply line for supplying wastewater from the inflow pump tank to the sludge anaerobic tank, and a supply control valve installed on the organic material supply line to control the supply amount. The method according to any one of claims 1 to 3, Wastewater advanced treatment apparatus, characterized in that the amount of waste water injected through the organic carbon supply unit is 10 to 20% of the low amount of the sludge anaerobic tank. Treating the wastewater introduced into the reactor while selectively performing anaerobic stirring and aerobic stirring; Drawing out excess sludge generated in the reactor to dehydrate the treatment; Discharging the supernatant in the wastewater passed through the reaction tank, and returning the sludge liquid deposited at the bottom to the sludge anaerobic tank; Improving a phosphorus removal microorganism by introducing a portion of wastewater before entering the reactor into the sludge anaerobic tank and storing the returned sludge liquid in the sludge anaerobic tank in an anaerobic manner; And removing sludge in excess of phosphorus from the improved microorganism by introducing wastewater overflowed from the sludge anaerobic tank into the reactor again.

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