KR20040079111A - Device and method for continuous feeding and intermittent discharge in sewage and wastewater treatment plant - Google Patents

Abstract

PURPOSE: To effectively carry out continuous inflow of wastewater and intermittent decant of treated water by installing an anaerobic basin and an anoxic basin respectively as well as operating two aerobic basins in turn, thereby increasing removal efficiency of nitrogen and phosphorus. CONSTITUTION: The apparatus comprises anaerobic tank(16) and anoxic tank(18) arranged in such a way that wastewater(11) and sludge(14,15) returned from aeration tanks(12,13) are continuously flown in the anaerobic tank and the anoxic tank so that the wastewater and return sludge are completely mixed and treated in the anaerobic tank and the anoxic tank; and two aeration tanks(13) which are installed separately from the anaerobic tank and the anoxic tank, and in which the wastewater and return sludge passing through the anaerobic tank and the anoxic tank are flown by a valve for controlling inflow of the wastewater and return sludge into the aeration tanks so that treated water is intermittently decanted out of the aeration tanks as aeration and settling are alternately being performed in the respective aeration tanks, wherein means are installed at the anaerobic tank and the anoxic tank so that sludge is returned to the anaerobic tank and the anoxic tank from the aeration tanks through the means, and wherein fixed type decanter(30) simply structured is installed at the aeration tanks to decant the treated water by siphon.

Description

Apparatus and method for continuous feeding and intermittent discharge in sewage and wastewater treatment plant

The present invention relates to a continuous inflow and intermittent discharge type sewage and wastewater treatment apparatus and method thereof. More specifically, the present invention can simultaneously remove not only organic matter but also nutrient components such as nitrogen and phosphorus in the biological treatment method of sewage and wastewater, and the batch treatment method of the conventional small scale biological sewage and wastewater treatment method is intermittent inflow. Although the daily throughput was limited by the intermittent discharge method of inflow and treated water, the present invention relates to a sewage and wastewater treatment apparatus and method which can be applied to large-scale treatment capacity by using a continuous inflow and intermittent discharge method.

The treatment facility of the conventional batch treatment method mainly consists of an equalization tank and a biological treatment reaction tank. The equalization tank functions to store the wastewater generated daily, and in the biological treatment reaction tank, the wastewater stored in the equalization tank is introduced in an amount to be treated and discharged after aeration and sedimentation process. The wastewater is treated by intermittent inflow and intermittent discharge which repeats the discharge process.

However, the batch treatment method of intermittent inflow and intermittent discharge is known to be possible only in small-scale treatment of agricultural and fishing villages where wastewater generation is uneven, but not applicable to large-scale generation areas.

Accordingly, in recent years, the treatment method has been switched to continuous inflow and intermittent discharge as a method for applying to medium and large scale treatment facilities. In other words, in the continuous inflow and intermittent discharge system, several partitions are installed in the biological treatment reactor, and the reactor is designed in the form of a plug flow in which the amount of pollutant removal increases according to the length of the reactor from the inlet port. After the treatment, the final treated water is discharged by the decanter when the water level is increased by the inflow flow rate (US Pat. Nos. 4,663,044, 4,693,821 and 4,891,128). In another method, the biological treatment reactor is designed in a complete-mix reactor flow, and the influent is injected through a hollow pipe installed at the bottom of the reactor to be moved upwardly. The technique for discharging the treated water by the decanter after being pushed to the upper part has been introduced (Korean Patent No. 242,042, Wastewater Treatment Method Using an Intermittent Discharge Long-Term Aeration Process).

However, continuous inflow of inflow water by the flow tank in the form of a flux flow and inflow of the inflow water into the upstream flow by the air pipe may cause inflow water to be mixed with the treated water. In addition, the discharge of the treated water is dependent on a movable arm or curtain wall decanter moving by a mechanical device, which has a problem that the device is complicated and expensive. .

In addition, organic matter removal and nutrient removal reactions such as phosphorus and nitrogen are made in one reactor, so there is a disadvantage in that the removal efficiency of phosphorus and nitrogen is low.

In addition, there is a problem that there is no way to deal with the failure of the device or other emergency by operating a single reactor.

The present invention is to solve the problems of the conventional continuous inlet and intermittent discharge type biological treatment reaction tank to increase the removal efficiency of nitrogen and phosphorus by installing an anaerobic tank and an oxygen-free tank separately from the aeration tank, the aeration tank is installed to operate two by turns Considering the mixing of influent and treated water and other emergencies, the discharge of effluent is aimed at improving the complicated discharge method by the decanter by using a fixed decanter using the siphon principle of water head difference. .

1 is a schematic diagram of a continuous inflow and intermittent discharge sewage and wastewater treatment apparatus according to the present invention.

FIG. 2 is a schematic perspective view of the discharge device of FIG. 1. FIG.

3 is a side view of FIG. 2.

11: influent 12, 13: aeration tank

14, 15: return sludge 16: anaerobic tank

17,25 stirrer 18 anoxic tank

19, 20: valve 28, 29: conveying pump

30: discharge device 31: inflow member

32: inlet 33: valve

34: discharge pipe 35: discharge port

The present invention relates to an anaerobic tank in which sewage and wastewater inflows containing organic matter, nitrogen and phosphorus are continuously introduced, an anoxic tank for further absorption of phosphorus and nitrogen removed from the anaerobic tank, and air to the effluent passing through the anoxic tank. A sewage and wastewater treatment system consisting of aeration tanks which repeats the process of supplying and biologically treating sludge and then discharging the final treated water intermittently. The improvement is that the sludge returned from the inflow water and the aeration tank is continuously introduced and Anaerobic and anaerobic tanks arranged for processing after mixing; The anaerobic tank and the anaerobic tank are installed separately, and the inflow water and the conveying sludge passing through them are introduced into the aeration tank by the valve means for controlling the inflow into the aeration tank, and then the aeration and sedimentation actions occur alternately in each aeration tank. , The treated water is characterized by consisting of two aeration tanks to be discharged intermittently.

In the apparatus according to the present invention, the anaerobic tank and the anaerobic tank are provided with means for transporting sludge from the aeration tank, respectively, and the anaerobic tank controls the inflow and conveying sludge through the anaerobic tank and the anaerobic tank to be alternately introduced. Valve means is provided.

In addition, according to the present invention, the aeration tank is provided with a fixed discharge device having a simple structure capable of discharging the treated water by the siphon principle, the fixed discharge device is formed along the lower surface of the inlet through which the treated water flows; The elliptical inlet member and the discharge pipe for discharging the treated water introduced into the inlet member to the outside is integrally configured. The discharge pipe is characterized in that the position of the discharge port at the discharge tip thereof is set lower than the level of the inlet port of the inflow member.

On the other hand, the present invention comprises the steps of continuously flowing the influent sewage water containing organic matter and nitrogen, phosphorus components into the anaerobic tank, further removing the phosphorus absorption and nitrogen in the anaerobic tank connected to the anaerobic tank, the anoxic tank Sewage and wastewater treatment method consisting of repeating the process of sending the effluent from the wastewater to the aeration tank to supply air and then settling sludge and discharging the final treated water intermittently. The improvement is from the inflow water and the aeration tank. Continuously flowing the returned sludge into the anaerobic tank and the anaerobic tank; Alternately operating the two aeration tank inlet valves in which the influent water and the return sludge which have been reacted in the anoxic tank are alternately disposed so that biological treatment occurs in each of the two aeration tanks separated from each other; And by repeatedly operating the step, the sludge is settled and then returned to the anaerobic tank and anoxic tank, characterized in that consisting of the step of discharging the treated water intermittently.

In the method of the present invention, the discharge of the treated water is discharged by the fixed decanter using the principle of siphon, but the discharge is made by the head difference by lowering the outlet than the inlet through which the treated water is introduced.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Figure 1 of the accompanying drawings in the present invention schematically shows a continuous inflow and intermittent discharge type sewage and wastewater treatment apparatus, Figure 2 is an enlarged perspective view showing the discharge device according to the present invention using the principle of the siphon 3 is a side view of FIG. 2.

As shown in FIG. 1, the sewage / wastewater treatment apparatus according to the present invention includes sludges 14 and 15 in which sewage / wastewater inflow 11 containing organic matter, nitrogen, and phosphorus is returned from the aeration tanks 12 and 13. ) Is mixed with the inlet into the anaerobic tank 16, the complete mixing of the influent 11 and the return sludge 14, 15 by the stirrer 17 in the anaerobic tank 16 takes place using the carbon source contained in the influent 11 Therefore, the nitrate nitrogen component contained in the phosphorus release and return sludge liquid in the microbial cells is reduced and removed by nitrogen gas.

As described above, the inflow water 11 and the conveying sludge 14 and 15 which passed through the anaerobic tank 16 flow in the direction indicated by the dotted line in FIG. 1 and are sent to the anaerobic tank 18. In the anaerobic tank 18, the anaerobic tank 16 is provided. Absorption of phosphorus released from the membrane occurs to some extent and at the same time the removal of nitrogen is more maximized.

The first inlet 11 and the return sludge 14 and 15 which have been reacted in the oxygen-free tank 18 flow in the direction of the arrow through the first aeration tank solenoid valve 19 installed in the oxygen-free tank 18 to perform the A reaction process. In the first aeration tank 12, air is supplied to absorb more phosphorus than the oxidation of organic matter contained in the influent, nitrification of nitrogen components contained in the influent, and the amount of phosphorus released from the anaerobic tank. The excess absorption of phosphorus occurs. After the air supply is finished in the first aeration tank 12, a precipitation process is performed in which the treated water and the sludge are solid-liquid separated, and after the precipitation is completed, the treated water is discharged through the discharge device 30 by the principle of siphon.

For example, the method of the present invention can be divided into an A reaction process in the first aeration tank 12 and a B reaction process in the second aeration tank 13. As illustrated in FIG. 1, the anaerobic tank 16 and the anaerobic tank are illustrated. Since 18 is one each, it is used jointly in A and B processes, and since the aeration tanks 12 and 13 are two, A and B reactions proceed separately. That is, as shown in Table 1, the A and B reaction progresses differently depending on time.

Table 1

A reaction process process anaerobe Anaerobic Aeration Sedimentation exhaust Total time: 360 minutes time 60 minutes 60 minutes 120 minutes 60 minutes 60 minutes B reaction process process Aeration Sedimentation exhaust anaerobe Anaerobic Total time: 360 minutes time 120 minutes 60 minutes 60 minutes 60 minutes 60 minutes

Accordingly, when the influent 11 and the return sludge 14 and 15 are completed in the anaerobic tank 18 through the anaerobic tank 16 in the reaction A, the anaerobic tank 16 and the anaerobic tank 18 are already removed in the reaction B. After the aeration of the inflow water 11 and the conveying sludge 14 and 15 introduced into the second aeration tank 13 is completed, and when the aeration is completed in the A reaction process, the second aeration tank 13 of the B reaction process is completed. Precipitation and discharge are completed. When precipitation is started again in the first reaction tank 12 of the A reaction process, the inflow water 11 and the return sludge 14 and 15 are introduced into the anaerobic tank 16 in the B reaction process.

As a result, the anaerobic tank 16 and the anaerobic tank 18 are installed one by one, respectively, and the first and second aeration tanks 12 and 13 are used separately, so that the influent 11 passes through the anaerobic tank 16 to the anaerobic tank 18. ), And the first and second aeration tanks 12 and 13 can be continuously introduced, and the first and second aeration tanks 12 and 13 in which aeration, sedimentation and discharge occur are alternately intermittently discharged.

According to the present invention, as shown in FIG. 1, the anoxic tank 18 is provided with two inlet solenoid valves. For the A reaction process, the first aeration tank inlet solenoid valve 19 located on the left side of the anoxic tank 18 is provided. Inflow and return sludge passed through the anaerobic tank 18 flows into the first aeration tank 12, while inflow and return sludge already passed through the anaerobic and anaerobic processes are transferred to the second aeration tank 13 in the B reaction process. Since the inflow and the reaction is in progress, the second aeration tank inflow solenoid valve 20 located on the right side is locked.

As a result, the progress of the alternating reaction in the aeration tank depends on the alternating action of the solenoid valves 19 and 20 installed in the oxygen-free tank 18, and the treated water after the aeration and sedimentation in the aeration tanks 12 and 13 is used while using water head difference. Discharge is made through the discharge device 30 by the phone principle.

Accordingly, according to the present invention, sludge return from the aeration tank to the anaerobic tank carried out for the sludge replenishment to the anaerobic tank 16 and the anoxic tank 18, the release of phosphorus from the sludge and the denitrification of the nitrate nitrogen nitrate in the aeration tank is A, B In each reaction process, the aeration is continued until the end of the aeration, the sludge return to the anaerobic tank 16 is made continuously.

In addition, one anaerobic tank 16 and one anaerobic tank 18 are each provided, and two aeration tanks 12 and 13 are installed to alternately discharge the aeration process, and the inflow can be continuously performed. . By using the aeration tanks 12 and 13 alternately, the machine can afford to cope with a malfunction or other emergency situation.

In Fig. 1, reference numeral 25 denotes an agitator provided in the oxygen-free tank 18, and reference numerals 28 and 29 denote first and second aeration tank sludge conveying pumps, respectively.

2 of the accompanying drawings shows a perspective view of the discharge device 30 using the principle of the siphon according to the present invention, the inlet member 31 of the discharged water is sludge accumulated on the surface of the device in the precipitation process after the aeration process In order to prevent the oval, the size of the inlet 32 formed along the lower surface of the oval is drilled circularly at the same and at regular intervals so as to prevent the sludge from being sucked up due to the flow rate is biased to one side. .

In general, the number of holes is preferably determined by designing a passage flow rate of 20 to 40 m / day in one hole. In the aeration tank, the position of the inflow member 31 is about 1 m at a height between the portion in which the inlet 32 is drilled and the sludge interface after sludge settling, and the height of the upper water layer from the inlet 32 is about 1 m. It is appropriate to have chickenpox about 1m. After completion of the settling process, the collecting pipe valve 33 of the discharge pipe is opened and the treated water passing through the inlet port 32 by the water head difference is discharged to the outside through the discharge pipe 34 and the discharge hole 35 at the tip thereof. Here, the position of the outlet 35 is preferably arranged lower than the level of the inlet 32, as shown in FIG.

As a result, after the sedimentation process is completed, the collection pipe valve 33 is opened and the treated water is discharged by the water head difference, and the discharged water level is up to the level at which the inlet 32 is located. In the present invention, since the treated water can be simply discharged by the fixed decanter of the siphon principle as described above, the decanter of the conventional female type and curtain type complicated structure is not required.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example

Using the actual sewage flowing into the sewage treatment plant, the plant with a daily treatment capacity of 10 tons / day was operated for about 6 months by continuous inflow and intermittent discharge. The operating conditions of the anaerobic and anaerobic tanks were 1 h for hydraulic operation and 8 h for each aeration tank. The microbial concentration in each reactor was about 4,500 mg / L, and the F / M (food / microorganism) ratio in the aeration tank was 0.1 kg BOD / kg MLSS · d. The settling time was 1 hour and the discharge time through siphon was 1 hour. The sludge return from the aeration tank to the anaerobic tank was four times the flow rate.

The following Table 2 shows the results of the average of the characteristics of the influent sewage and treated water operated for 6 months, and the following Table 3 is the measurement data showing the behavior of organic matter, phosphorus and nitrogen in each unit process.

The treated water quality of COD and BOD is less than 20mg / L, the removal efficiency is more than 90%, and the treated water quality of TKN is 2mg / L and the nitrification efficiency is 95%, so that organic matters and nitrogen components are completely oxidized. Could know. And the oxidized nitrogen component played a role of an anaerobic tank that performs denitrification and an anaerobic tank that performed the release function of phosphorus, so the removal efficiency of total nitrogen and total phosphorus was 75% and 94%, respectively. In addition, the SS concentration of the effluent indicates 5mg / L, it can be seen that the treatment water discharge device of the present invention using the siphon principle is properly performed.

The following Table 3 shows the specific measurement of the behavior of organic matter, nitrogen, phosphorus in order to determine the role of the biological treatment unit of the present invention. In the anaerobic tank, phosphorus is released from microbial cells, which is higher than the influent concentration. However, the aeration process shows that the microorganisms absorb the phosphorus excessively and maintain very low concentration in the wastewater. In the case of nitrate nitrogen, the nitrogen component should be oxidized in the aeration tank to maintain a very high concentration of nitrate nitrogen, but it is reduced in the anaerobic tank, which shows that the system is very low.

In addition, in the oxidation-reduction potential value that determines the proper progress of anaerobic, oxygen-free, and aeration processes, the anaerobic tank and the oxygen-free tank have negative values, indicating a reducing state, which is an appropriate environment for removing phosphorus and nitrogen, and the aeration tank is an organic substance and a nitrogen component. A positive value is shown, which is a suitable environment for oxidation of.

Table 2 (Unit: mg / L)

Item COD BOD SS TKN NO ₃ -N T-N T-P Influent 350 168 120 39 One 40 8 Treated water 20 12 5 2 8 10 0.5 Processing efficiency (%) 94 93 96 95 - 75 94

COD: chemical oxygen demands

BOD: Biological Oxygen Demands

SS: suspended solids

TKN: Total Kjeldahl Nitrogen (Organic Nitrogen + Ammonia Nitrogen)

NO ₃ -N: nitrate nitrogen

T-N: total nitrogen (TKN + nitrate nitrogen)

T-P: Total phosphorus (SS containing + Soluble Phosphorus)

TABLE 3

Item Influent Anaerobic tank Anaerobic Aeration tank Sedimentation exhaust SCOD (mg / L) 180 95 60 10 8 8 S-P (mg / L) 5 22 13 0.3 0.3 0.3 NO ₃ -N (mg / L) 0.1 5 3 8 6 6 ORP (mv) -300 -150 -50 +250 +230 +230

SCOD: soluble COD

S-P: Soluble Phosphate

ORP: oxidation-reduction potential

Comparative example

In order to compare the performance with the apparatus of the present invention, as a comparison process, Korean Patent No. 242,042 (Wastewater treatment method using an intermittent discharge long-term aeration process) was operated with the same daily treatment capacity as the embodiment of the present invention, and the operation was 10 tons / day. The method was a continuous inflow, intermittent discharge method, was installed in parallel with the experimental apparatus of the present invention.

The experimental apparatus of the comparative example is anaerobic, anaerobic, aeration, sedimentation process is carried out in one reactor, the inflow of the inflow method was carried out through a hole pipe installed in the lower part of the reactor, the discharge of the treated water was used a female decanter. All experimental conditions such as total hydraulic retention time, microbial concentration and F / M ratio in the reactor were the same as in Example. The results are shown in Table 4 below.

Table 4 (Unit: mg / L)

Item COD BOD SS TKN NO ₃ -N T-N T-P Influent 350 168 120 39 One 40 8 Treated water 25 15 15 8 12 20 2.5 Processing efficiency (%) 93 91 88 79 - 50 69

According to Table 4, the removal efficiency of organic matters such as COD, BOD and the like was somewhat lower than the results performed in the embodiment of the present invention, the removal efficiency of the nitrification efficiency of nitrogen, phosphorus and the like of TKN was very low.

This is because the inflow water is mixed with the treated water because the treated water is pushed up by the flow rate flowing into the upstream by the perforated pipe, and the removal of phosphorus and the denitrification reaction are mixed without distinction and occur in one reactor. Also, in the SS removal efficiency, the decanter of the comparative example was driven by a mechanical operation, so that the surface of the water was disturbed, causing the sludge to float. On the other hand, in the embodiment of the present invention, there is little loss of SS because of only the reduction of the water level by the fixed operation and no disturbance.

As in the present invention, in the wastewater treatment apparatus configuration, one anaerobic tank and one anaerobic tank, which are phosphorus and nitrogen removal devices, are installed one by one, and the aeration tank, which is an organic material removal and nitrogen oxidation tank, is divided into two and operated in turn so that continuous inflow of inflow water, The intermittent discharge of the treated water can be effectively performed, and the sludge is returned to the anaerobic tank during the continuous inflow and the intermittent discharge process to maximize the removal of nitrogen and phosphorus throughout the system. In addition, by using a fixed decanter using a siphon as a method of discharging the treated water, the facility is simpler than a conventional female decanter and the SS removal efficiency can be improved.

Claims (7)

By supplying air to the anaerobic tank into which sewage and wastewater inflows containing organic matter, nitrogen and phosphorus flow continuously, an anoxic tank to remove phosphorus and nitrogen further removed from the anaerobic tank, and effluent passing through the anoxic tank In the sewage and wastewater treatment apparatus consisting of aeration tank repeating the process of sedimentation and the final treated water is intermittently discharged after treatment with, Anaerobic tank 16 and anoxic tank 18 disposed so that sludges 14 and 15 conveyed from the inflow water 11 and the aeration tanks 12 and 13 can be continuously introduced and treated after complete mixing; The anaerobic tank 16 and the anaerobic tank 18 are provided separately, and the inflow water 11 and the conveying sludge 14 and 15 through these anaerobic tanks and the anaerobic tank control valve means 19 and 20 for controlling the inflow into the aeration tank. After flowing into the aeration tank, the aeration and sedimentation occur alternately in each aeration tank, and the treated water is composed of two aeration tanks 13 intermittently discharged. Wastewater treatment device. 2. The continuous inflow and intermittent discharge type according to claim 1, wherein the anaerobic tank 16 and the anaerobic tank 18 are provided with means for transporting sludge from the aeration tanks 12 and 13 to be introduced therein. Wastewater treatment device. 2. The continuous inlet and intermittent discharge type of claim 1, wherein the aeration tanks 12 and 13 are provided with a fixed discharge means 30 having a simple structure capable of discharging the treated water by the siphon principle. Wastewater treatment device. The method of claim 3, wherein the fixed discharge means 30 is an elliptical inlet member 31 having an inlet 32 through which the treatment water is introduced is formed along the lower surface and the treated water introduced into the inlet member 31. A continuous inflow and intermittent discharge sewage and wastewater treatment apparatus, characterized in that the discharge pipe 34 to be discharged to the outside is integrally formed. 5. The continuous inflow and intermittence of the discharge pipe (34) according to claim 4, wherein the discharge pipe (34) is set at a position where the discharge hole (35) at its distal tip is lower than the level of the inlet hole (32) of the inflow member (31). Effluent sewage and wastewater treatment device. Continuously flowing inflow of sewage and wastewater containing organic matter, nitrogen and phosphorus into the anaerobic tank, removing phosphorus from the anoxic tank connected to the anaerobic tank and removing nitrogen further, and aeration tank of the anaerobic tank and anoxic tank. In the sewage and wastewater treatment method which consists of repeating the process of biologically treating and sending sludge and intermittently discharging the final treated water while supplying air to the air. Continuously introducing the inflow water and sludge conveyed from the aeration tank into the anaerobic tank and the anaerobic tank; Operating the two aeration tank inlet valves alternately by operating the two aeration tank inlet valves passing through the anaerobic tank to two aeration tanks installed on both sides so that biological treatment occurs alternately in the aeration tank; And repeatedly operating the step to settle the sludge, and then returning the sludge to the anaerobic and anoxic tanks, and discharging the treated water intermittently. 7. The continuous inflow and intermittent discharge according to claim 6, wherein the discharge of the treated water is discharged by a fixed decanter using the principle of siphon, but discharged by water head lower than the inlet of the treated water. Sewage and wastewater treatment method.