KR100365314B1 - Waste-Water Disposal System And Method For Removing Nitrogen, Phosphorus and Sludge by Using Aerobic and Anaerobic logarithmic/Endogenous Microorganism growth - Google Patents

Abstract

The present invention relates to a wastewater treatment apparatus in which an anaerobic contact tank, an aerobic lagoon-style aeration tank and a suspension microbial contact oxidation tank are compactly combined with one settling tank, and a method for treating wastewater using the wastewater treatment apparatus. According to the wastewater treatment method of the present invention, the anaerobic microorganisms in the anaerobic contacting tank are cleaved to make a ring suitable for oxidative decomposition by the aerobic microorganism. In addition, the anaerobic contact tank is a closed form, it is possible to improve the efficiency of the process by using a gas generated by the decomposition of anaerobic microorganisms as an external carbon source for denitrification in the denitrification tank. In addition, in the present invention, by performing aerobic oxidative decomposition in a lagoon-type long-term aeration tank in which the F / M ratio is lower than a conventional aeration tank and operated in the endogenous growth stage of microorganisms, wastewater can be treated with very little sludge and suspended matter. Unevenness of the discharge water quality due to excessive load of the waste water can be prevented. In addition, in order to give an appropriate sludge (microorganism) residence time in the lagoon-type long-term aeration tank, the sludge can be taken out from the lagoon-type long-term aeration tank at a suitable time to prevent the occurrence of pin floes and re-elution of phosphorus.

Description

Waste-water disposal system and method for removing nitrogen, phosphorus and sludge by using aerobic and anaerobic logarithmic / endogenous microorganism growth}

The present invention relates to a wastewater treatment apparatus and method, and in particular, anaerobic contact tank, aerobic lagoon aerobic tank and suspension microbial contact oxidation tank compactly combined with one settling tank, anaerobic and aerobic algebra of the microorganism, endogenous growth The present invention relates to a wastewater treatment apparatus for removing nitrogen, phosphorus and sludge using a step and a wastewater treatment apparatus using the wastewater treatment apparatus.

In general, when the wastewater is treated in a factory, various methods are adopted depending on the quality of the wastewater. Some chemical treatments, including neutralization and flocculation, may be employed. Others may employ biological treatments such as biological membranes, catalytic oxidation, activated sludge, special biological treatments and anaerobic treatments. In some cases, physical treatment processes such as adsorption, flotation and membrane treatment processes may be employed.

Currently, most organic wastewaters, especially aquatic product wastewaters, use chemical precipitation or chemical flotation as the primary treatment and standard activated sludge as the secondary treatment. However, the problem with this method is that the amount of chemical consumption and sludge generation is too high, and one expert and one middle worker must always reside in the operation, especially for small and medium-sized companies that have to treat small-scale wastewater. Its processing capacity is low for cost. In addition, the standard activated sludge method is sensitive to the environmental conditions of the microorganisms, there is a disadvantage in that it takes a long time to balance the microbial conditions as well as fluctuations in the discharge water quality. Normal sludge dwell time (SRT), lack of dissolved oxygen (DO), and high F / M (Food / Microbe) ratio cause over-80% of water deterioration resulting in unbalance in the aeration tank. do.

Accordingly, there is a need for a wastewater treatment apparatus which requires less chemical consumption and sludge generation, has a low treatment cost, has a uniform discharge water quality, and does not generate an imbalance in the system.

An object of the present invention is to treat high concentration organic wastewater, there is no sludge generation and chemical consumption, low wastewater treatment cost, very high denitrification efficiency and phosphorus removal efficiency, and can obtain a steady good discharge water quality, apparatus Or it is to provide a wastewater treatment device that is easy to manage because the structure of the system is simple.

It is also an object of the present invention to provide a method for treating wastewater using the wastewater treatment apparatus.

1 is a flow chart showing a process for treating a high concentration of organic wastewater using a wastewater treatment apparatus according to an embodiment of the present invention.

2 is a schematic view showing a wastewater treatment apparatus and a wastewater treatment method according to an embodiment of the present invention.

3 is a view showing the internal structure and the connection structure of the anaerobic contact tank and the first anaerobic tank of FIG.

4 is a view showing the structure of the lagoon-type long-term aeration tank and the second anaerobic tank of Figure 2 and the structure of the baffle for automatic solid / liquid separation.

5 is an internal structure diagram of the sludge oxidizing tank.

6 is a schematic view showing a wastewater treatment apparatus and a wastewater treatment method according to another embodiment of the present invention.

Figure 7 shows a graph comparing the microbial growth curve for the lagoon-type long-term aeration method used in the present invention with those for the standard activated sludge method and conventional long-term aeration method.

* Description of the main parts of the drawing.

10: sedimentation and oil and water separation tank 11: collection tank

12: anaerobic contact tank 13: denitrification tank (oxygen tank)

14 lagoon-style aeration tank 15 denitrification tank (anoxic tank)

16: contact aeration tank 17: sedimentation separation tank

18: Sludge Oxidation Tank 19: Gas Collection & Dissolution Facility

The wastewater treatment apparatus of the present invention has an inlet pipe and a discharge pipe, and includes a closed anaerobic contact tank, a first anaerobic tank connected to the anaerobic contact tank by the discharge pipe of the anaerobic contact tank, and a first anaerobic tank connected to the first anaerobic tank. 1 a lagoon-type long-term aeration tank, sludge oxidatively decomposing wastewater including sludge received from the lagoon-type long-term aeration tank connected to the suspension microorganism contact oxidation tank (contact aeration tank) connected to the first lagoon-type long-term aeration tank An oxidation cracking tank or one or more additional lagoon aeration tanks, and a precipitation tank connected to the suspension microbial contact oxidation tank, wherein a portion of the wastewater entering the first lagoon long-term aeration tank is fed back to the first anoxic tank.

A first anoxic tank (denitrification tank) may be interposed between the first lagoon type long-term aeration tank and the microbial contact oxidation tank.

The wastewater fed back from the first lagoon type aeration tank may be fed back from the first lagoon type aeration tank to the denitrification tank via the additional lagoon type aeration tank, or directly to the denitrification tank. In addition, the first lagoon-type aeration tank and the additional lagoon-type aeration tank is connected to each other has a structure that the waste water of the first lagoon-type long-term aeration tank overflows and is transferred to the additional lagoon-type aeration tank, the additional lagoon-type aeration tank A portion of its wastewater may be fed back to the denitrification tank and at the same time a portion overflows into the microbial contact bath and is transported.

The wastewater treatment apparatus further includes a sludge storage tank, and the sludge storage tank may be stored to discharge sludge (microorganisms) drawn out from the first lagoon type long-term aeration tank.

The sludge precipitated in the sedimentation tank may be fed back to the anaerobic contacting tank by blowing an air lift, or may be transported to the sludge oxidative decomposition tank or sludge storage tank, and then fed back to the anaerobic contacting tank.

The anaerobic contact tank is preferably formed of a net-shaped filling medium (media) to which anaerobic microorganisms are attached, and a baffle is formed to smooth the flow of wastewater, and the filling material is formed by sludge. It is recommended that an internal sludge circulator is installed to prevent clogging.

The exhaust pipe of the anaerobic contact tank is a T-shaped pipe, and may have a first end submerged in the wastewater, a second end located at a position higher than the level of the wastewater, and a third end positioned in the first anoxic tank. As a result, the gas generated by the anaerobic microorganism can be transferred to the first anoxic tank together with the wastewater. The anaerobic contacting tank may be installed underground to prevent excessively lowering the temperature below an appropriate temperature in winter, and may be transferred to the first anoxic tank when the generated gas pressure of the anaerobic contacting tank is 0.1 kg / cm ^{2 or} more. Further, the gas generated in the anaerobic contacting tank can be stirred while being injected by the apparatus for injecting the wastewater of the anaerobic contacting tank. As a result, the generated gas may be transferred from the anaerobic contacting tank to the first anoxic tank through a pipe connecting the anaerobic contacting tank and the first anaerobic bath. The anaerobic contact tank is a heating device for heating the wastewater, and using high frequency induction current, the anaerobic contact tank can be transformed into low temperature, medium temperature, and high temperature microorganisms in proportion to the load caused by the fluctuation of the wastewater inflow.

The first lagoon-type long-term aeration tank is formed with a baffle serving as a sedimentation tank at the position where the waste water overflows and is transferred from the lagoon-type long-term aeration tank to the next tank, and a gap is formed at the bottom of the baffle. Precipitated sludge may escape into the gap and be mixed with wastewater of the lagoon-type long-term aeration tank, or the precipitated sludge may be withdrawn from the first lagoon-type long-term aeration tank.

In another aspect, the present invention provides a wastewater treatment method for treating wastewater containing a high concentration of organic matter using the wastewater treatment apparatus.

According to the wastewater treatment method of the present invention, the anaerobic microorganisms in the anaerobic contacting tank are cleaved to make a ring suitable for oxidative decomposition by the aerobic microorganism. In addition, the anaerobic contact tank is a sealed form, by using the gas generated by the decomposition of the anaerobic microorganism as the external carbon source for denitrification in the first step anoxic tank (denitrification tank) to improve the efficiency of the process. At this time, by properly maintaining the gas pressure of the generated gas, the generated gas can be transferred to the first anoxic tank (denitrification tank) together with the waste water by the T-shaped pipe. In addition, in order to improve the efficiency of the anaerobic contacting tank, the generated gas may be injected into the wastewater and stirred, and the generated gas may be heated by a high frequency induction current to maintain an appropriate temperature of the wastewater. At this time, the generated gas injected into the waste water is transferred to the first anoxic tank (denitrification tank) which is the next step together with the waste water.

In addition, in the present invention, by performing aerobic oxidative decomposition in a lagoon-type long-term aeration tank in which the F / M ratio is lower than a conventional aeration tank and operated in the endogenous growth stage of microorganisms, not only the wastewater can be treated without the occurrence of sludge and suspended matter, but also the excessive amount of the wastewater. Unevenness of discharge water quality due to load can be prevented. However, if oxidative decomposition is performed for an excessive amount of time in a lagoon-type long-term aeration tank, problems may arise due to the occurrence of pin floc and re-elution of phosphorus. By taking the sludge out of the lagoon type long-term aeration tank, it is possible to prevent the occurrence of pin floes and re-elution of phosphorus.

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

1 is a flow chart showing a process for treating a high concentration of organic wastewater using a wastewater treatment apparatus according to an embodiment of the present invention. 2 is a schematic view showing a wastewater treatment apparatus according to an embodiment of the present invention. An embodiment of the present invention will be described with reference to the drawings.

1 and 2, the wastewater treatment apparatus of the present invention is connected to the anaerobic contact tank 12, the first anaerobic tank (denitrification tank) 13, the lagoon-type long-term aeration tank 14, the second anoxic tank (denitrification tank) ), A suspension microbial contact oxidation tank (contact aeration tank) 16, and a sludge oxidative decomposition tank 18 in which a part of the wastewater is transferred from the settling tank 17 and the lagoon type long-term aeration tank 14. The water tanks of the wastewater treatment apparatus of the present invention are provided with an airlift device for transferring or feeding back the wastewater by the air flow blown by the blower.

First, the high concentration organic wastewater is introduced into the sedimentation and runoff separation tank 10 by natural flow or forced transfer. This removes rags and other foreign matter such as sand, gloves, and packing materials mixed in the wastewater. The sludge mixed in the waste water is transferred to the sludge oxidation cracking tank 18 by an air lift device using the air flow of the blower. This reduces the load on subsequent processes. The wastewater treated in the sedimentation and oil / oil separation tank 10 is transferred to the water collection tank (flow control tank) 11 by overflow. The sump 11 is provided with a pump in order to maintain a constant flow of wastewater in a subsequent process even if the introduction amount of the wastewater into the sedimentation and oil-water separation tank 10 is not constant. The wastewater collected in the sump 11 is forcibly transported by a pump installed instead of being transferred to the next tank due to overflow. The wastewater forcibly transported from the sump 11 is introduced into the anaerobic contact tank 12.

3 is a view showing the internal structure and the connection structure of the anaerobic contact tank and the first anaerobic tank of FIG.

The anaerobic contact tank 12 is provided with an inlet pipe and a discharge pipe. The anaerobic contacting tank 12 is completely sealed except for the penetration of the inlet pipe and the outlet pipe. A baffle (not shown) is provided to keep the flow of wastewater introduced into the anaerobic contacting tank 12 constant. In addition, a net-shaped filling medium (media) to which anaerobic microorganisms are attached is formed at predetermined intervals. Filling media should be a carrier in the form of a blanket, such as AQUATIC among commercial media. In addition, the anaerobic contact tank 12 is provided with an internal sludge circulation device (not shown) to prevent clogging of the net-shaped filling medium. Therefore, sludge conveyance and stirring are unnecessary. The internal sludge circulator is an airlift device that blows airflow from the blower in the opposite direction of the flow of wastewater. This is used in the anaerobic contact tank when clogging occurs due to the adhesion of sludge to the surface of the filler and the flow of wastewater is slowed down.

The level of wastewater in the anaerobic contacting tank 12 is usually kept constant, and about 70% or more of methane gas is generated by the decomposition of organic matter in the wastewater of anaerobic microorganisms. The generated gas is collected in the upper part of the waste water level without being discharged to the atmosphere because the anaerobic contact tank 12 is sealed.

The discharge pipe is T-shaped. The first end of the discharge pipe is installed to be submerged in the waste water. The second end is installed at a position above the level of the wastewater. That is, the gas generated by the anaerobic microorganisms is exposed and installed in the filled space. A pipe connected to the third end penetrates through the wall of the anaerobic contact bath 12 and the third end is located in the first anaerobic bath 13.

Therefore, when the wastewater is treated by the apparatus of the present invention, the generated gas collected on the anaerobic contacting tank 12 is naturally transported with the wastewater to the first water tank 1, which is the next tank, by the pressure. At this time, the gas pressure for transferring the generated gas with the waste water to the denitrification tank may vary depending on the depth of the pipe connected to the denitrification tank of the T-shaped pipe. The gas pressure designed to naturally transport the generated gas may be 0.1 kg / cm ^{2 or} more, and typically, the gas pressure may be maintained in the range of 0.1 to 0.3 kg / cm ² . And in order to maintain the gas pressure in winter and to prevent excessively falling below an appropriate temperature, the anaerobic contact tank 12 is preferably installed in the basement surrounded by a heat insulating material.

On the other hand, in order to improve the organic decomposition of the anaerobic contacting tank, and to be able to transport the generated gas even at low gas pressure, the anaerobic contacting tank may be provided with a device and a heating device capable of injecting the generated gas into the wastewater. In order to inject the generated gas into the wastewater of the anaerobic contacting tank, a pipe submerged into the wastewater is installed, and the generated gas collected on the upper part of the anaerobic contacting tank is blown into the wastewater through the piping by the air lift. The generated gas injected into the waste water is transferred to the denitrification tank together with the waste water through a connecting pipe connected between the anaerobic contact tank and the denitrification tank. This allows the offgas to be transferred from the anaerobic contact bath to the denitrification bath even at lower gas pressures. Injection of the generated gases serves to agitate the wastewater, thus facilitating the degradation of anaerobic microorganisms. In addition, the wastewater in an anaerobic contact tank can be further stirred using a separate stirrer separate from the generating gas injection device. In addition, by heating the waste water with a heating device by a high frequency induction current it is possible to improve the anaerobic decomposition of the organic material by increasing the growth and activity of the mesophilic microorganisms and hot microorganisms more active in anaerobic microorganisms. In addition, by controlling the heating of the wastewater by the heating device, it is possible to appropriately control the wastewater treatment in the anaerobic contacting tank in accordance with the fluctuation of the amount of incoming wastewater entering the anaerobic contacting tank. That is, when the amount of inflow wastewater is small, the anaerobic treatment by low temperature microorganisms accounts for a large proportion as it is not heated, and as the amount of inflow wastewater increases, the ratio of anaerobic treatment by mesophilic or high temperature microorganisms is large. This can increase the control capacity of the wastewater treatment in the anaerobic contact tank. The heating of the wastewater by the heating device may be performed by heating the generated gas by installing a coil through which the high frequency induction current flows, in the upper layer of the anaerobic contact tank where the generated gas is collected and flowing a high frequency induction current. At this time, the heating can be adjusted according to the amount of wastewater introduced into the anaerobic contact tank, and if there is no change in the amount of wastewater introduced, it is better to raise the temperature to the optimum temperature of the high temperature microorganism, but in terms of energy efficiency, the optimum temperature of the medium temperature microorganism It would be desirable to raise it to.

The efficiency improving factors of the anaerobic contact tank allow to reduce the size of the anaerobic contact tank of the present invention. In addition, by adjusting the temperature of the wastewater according to the fluctuation of the inflow of the wastewater into the anaerobic contact tank, it is possible to treat the wastewater in proportion to the amount of the influent wastewater. In addition, an increase in the anaerobic contact tank temperature results in an increase in the temperature of the denitrification tank, which also increases the denitrification efficiency.

Anaerobic microorganisms decompose hardly decomposable organic substances such as polymers into degradable organic substances. Anaerobic microorganisms do not completely decompose organic matter, so it is difficult to completely treat the wastewater alone, but the primary treatment of wastewater containing high concentrations of hardly decomposable organic matter allows the aerobic microorganism to completely decompose properly decomposed organic matter. On the other hand, aerobic microorganisms can degrade hardly degradable organic substances such as polymers, but they are very slow. In other words, when trying to decompose hardly decomposable organic materials using only aerobic microorganisms, the microorganisms may be overloaded, have a high F / M ratio, and lack of dissolved oxygen (DO), causing microbial plaque to disintegrate and not be precipitated. In addition, steady discharge quality cannot be obtained due to overloading. Therefore, the treatment of only aerobic microorganisms is insufficient to treat wastewater containing a high concentration of hardly decomposable organic substances such as aquatic product wastewater. However, aerobic microorganisms are not effective in treating poorly degradable organic substances but are effective in degrading moderately degraded organic substances. Therefore, in the present invention, by treating the anaerobic microorganisms in the anaerobic tank and the aerobic microorganisms in the aerobic tank continuously, it is possible to efficiently treat the high concentration of organic wastewater, especially wastewater containing hardly decomposable organic matter.

On the other hand, the nitrogen in the waste water exists in organic form (protein, urea, etc.) and inorganic form (ammonia, etc.), which is decomposed into ammonia nitrogen through amino acid nitrogen by microorganisms (Bacteria), ammonia nitrogen Is nitrified to nitrate nitrogen by microorganisms (Nitrosomonas, Nitrobactor), which is nitrified to nitrogen gas by microorganisms (Pseudomonas, Micrcoccus, Spirillum, Alcaligenes) and released into the atmosphere. In anaerobic contacting tanks, organic nitrogen and ammonia nitrogen are nitrated (or nitrified) with nitrate nitrogen by anaerobic microorganisms.

Next, the wastewater treated in the anaerobic contacting tank 12 is transferred to the first anoxic tank 13 together with the gas generated by the anaerobic microorganisms. In an anaerobic bath, nitrification occurs in which the nitrogen content is converted to nitrogen in the anaerobic contact bath. In order to achieve nitrification in anoxic tanks, nutrients are needed for nitrifying microorganisms. Typically, this nutrient source provides an external carbon source such as methanol. However, in the present invention, methane gas in the gas generated by the anaerobic microorganisms of the anaerobic contacting tank is used as this carbon source. In addition, the anaerobic contact tank does not completely decompose the organic matter, but rather decomposes the organic matter in an appropriate size, so that the decomposed organic matter acts as an internal carbon source in the denitrification tank, so that the denitrification efficiency is very high. This is one of the features of the present invention. In order to facilitate the denitrification in the anoxic tank 13, the waste water is stirred using a stirrer.

In anaerobic contacting tanks, they have low molecular weights through the fermentation and acid production stages with short residence times, but the pH is about 6 because they do not undergo complete methane production stages.In denitrification tanks, long SRTs and some peroxidized and over-aerated internal return sludges ( Due to the high pH (described below) of 7.5-9.5, the pH of the mixed solution is maintained at about 6.5-7.5, so there is no need to adjust the pH.

In the denitrification tank, wastewater residence time (HRT) is increased by the relatively high anaerobic treated water, slow rate of propagation of microorganisms and excessive nitrification, which leads to increased redox potential and reduced anaerobic stress. It is maintained in the range of 1.5-3.5 hours, and the conveyance rate of the internal conveyed sludge from a lagoon type long-term aeration tank is 150-250% (described later).

Next, the wastewater denitrated in the first anaerobic tank 13 is transferred to the lagoon-type long-term aeration tank 14 by overflow.

The lagoon-type long-term aeration tank used in the present invention may be referred to as a tank applied to the present invention by applying the concept of a long-term aeration tank using a lagoon method (lagoon tank) and a long-term aeration method.

Long-term aeration methods use long-term aeration tanks to reduce the occurrence of excess sludge by exposing long-term (16-24 hours) wastewater (microorganisms) to aeration. However, in the treatment of high concentration organic wastewater, due to the overload of the high F / M ratio, as described above, suspended solids are generated due to the microbial flocculation, and the discharge water quality is not uniform, and it is difficult to operate. In addition, when the microorganism (sludge) residence time (SRT) is usually 30 days or more, a pin floc phenomenon occurs in which a microorganism is decomposed and a white float is generated. Since the suspended solids generated by this pin-flop phenomenon is not precipitated in the sedimentation tank, the suspended solids are included as discharged water and discharged, so the quality of the discharged water is deteriorated.

The lagoon method is to supply microorganisms with dissolved oxygen from the atmosphere without using aeration. Therefore, the tank according to the lagoon method has to maintain a low water level, there was a problem that the size of the tank increases.

The lagoon-type long-term aeration method used in the present invention can expose the wastewater (microorganism) in the lagoon-type long-term aeration tank to about 60 to 96 hours, and even if the retention time of the microorganism is increased to about 90 days, the pin floc phenomenon does not occur very much. . This is an advantage that the size of the tank is slightly increased compared to the size of the conventional long-term aeration tank, but the performance improvement is superior to the increase amount.

While the F / M ratio of the conventional long-term aeration method is about 0.04, the F / M ratio of the lagoon-type long-term aeration method of the present invention is wide, ranging from 0.01 to 0.1. As described in the second embodiment below, this means that there is a difference in the F / M ratio from the first lagoon aeration tank to the final lagoon aeration tank (sludge oxidation cracking tank), and to increase phosphorus removal efficiency. Sludge withdrawal takes place from the first lagoon type aeration tank with a slightly higher F / M ratio of 0.05 to 0.1. Typically, the first lagoon-type aeration tank is operated at a rather high F / M ratio of 0.05 to 0.1, and the additional lagoon-type aeration tank is operated at a lower F / M ratio of 0.01 to 0.05 (below) in detail. Explained).

In the lagoon-type long-term aeration tank of the present invention, since the microorganisms are aerated for a long time in the endogenous growth stage, the cells are endogenous respiration and self-decomposition (self-oxidation), so that almost no sludge is generated.

In addition, the pinflow phenomenon does not occur because the wastewater is returned to the anaerobic tank 13 to denitrify the excessively nitrified wastewater and to prevent the occurrence of the pinflood phenomenon, thereby substantially reducing cell age and microbial residence time. In addition, the microbial cell age in the lagoon-type long-term aeration tank 14 is transferred to the sludge oxidizing tank 18 where it is completely oxidized by excessive oxidation and returned to the anaerobic contact tank. And reduce the microbial residence time to prevent the occurrence of pin flocs.

On the other hand, in the conventional aeration tank, the F / M ratio is high and the microorganism (sludge) residence time is short, so that the microorganism tank is deteriorated in a moment, and normalization requires a long time, whereas in the lagoon-type aeration tank of the present invention, the microorganism residence time can be increased. In addition, even if the supernatant of the treated water becomes turbid (pin floc occurrence) due to excessively long microbial retention time, it proceeds very slowly and can be easily determined with the naked eye. Normalization is possible within. That is, the lagoon-type long-term aeration tank of the present invention does not generate a sudden flocculation phenomenon because the load of waste water is rather low and the amount of dissolved oxygen is excessive, and even if some non-precipitable particles are formed due to excessive microbial retention time, It can buffer load fluctuations in the oxidizing tank to keep the water quality constant.

In addition, as in the other embodiments of the present invention described below, even if the pin flock is formed can be quickly normalized by adjusting the microbial retention time small and high F / M ratio by appropriately withdraw the microorganisms. Since the lagoon-type long-term aeration tank of the present invention has a long microbial retention time and a long aeration time, sludge is generated by releasing gas (CO _2, etc.) generated by oxidative decomposition by microorganisms, not by adsorption and aggregation precipitation by microorganisms. It is designed based on the concept of preventing this. Therefore, in the lagoon-type aeration tank of the present invention, there is no necessity to carefully observe the microorganisms.

In anaerobic contacting tanks, dephosphorus bacteria such as Acinetbacter can release phosphorus at the same time as they consume fermentable substances, and then additionally ingestion of phosphorus in the lagoon-type long-term aeration tank can additionally achieve phosphorus removal effect. However, as the microorganism reaches the endogenous growth stage, better floc formation, better sedimentation, and a decrease in cell volume, but due to self-oxidation, microorganisms can be re-released to lower phosphorus removal efficiency. In order to improve the phosphorus removal efficiency, a method of improving the method described herein will be described with reference to FIG. 6 below.

In FIG. 2, the wastewater treated in the sludge oxidizing tank 18 is returned to the water collecting tank 11 and consequently returned to the anaerobic contacting tank 12. However, the sludge oxidizing tank 18 in the anaerobic contact tank ( 12) may be directly returned.

On the other hand, nitrification may occur due to excessive oxidation in the lagoon type long-term aeration tank 14. However, this peroxidation allows the nitrogen component to be completely nitrified, and the nitrified nitrogen component is denitrified through the return to the anaerobic tank 13 and the anaerobic contacting tank 12 through the sludge oxidizing tank 19. It may be denitrified in a second anoxic tank (denitrification tank) 15, which is the next step.

As a result, the wastewater treated in the lagoon type long-term aeration tank 14 of the present invention is partially returned to the first anoxic tank 13, partially transported to the sludge oxidative decomposition tank 18, and partially transported to the second anoxic tank 15. . At this time, conveyance to the first oxygen-free tank 13 and conveyance to the sludge oxidative decomposition tank 18 are performed by the air lift apparatus, and conveyance to the second oxygen-free tank 15 is performed by overflow.

4 is a view showing the structure of the lagoon-type long-term aeration tank and the second anaerobic tank of Figure 2 and the structure of the baffle for automatic solid / liquid separation.

Referring to Figure 4, the lagoon-type long-term aeration tank of the present invention is formed with a baffle that serves as a sedimentation tank at the position where the waste water overflows and is transferred from the lagoon-type long-term aeration tank 14 to the second anaerobic tank 15. This baffle has a gap formed in the lower part of the baffle, and a slanted surface is formed so that the sludge settled out is discharged through this gap and mixed with the wastewater of the lagoon type long-term aeration tank 14 to be treated.

5 is an internal structure diagram of the sludge oxidizing tank.

A sludge oxidizing tank 18 is formed with a partition having a lower opening to distinguish the aeration portion and the sludge withdrawal portion. The introduced sludge is oxidized at the aeration part and is transferred to the withdrawal part through a gap formed in the lower part of the baffle and then transferred to the anaerobic contact tank.

The sludge introduced into the sludge oxidation cracking tank 18 may be sludge generated in a lagoon type long-term aeration tank. In lagoon type aeration tanks, theoretically little sludge occurs, but sludge may be caused by various factors such as unbalance of operation, and may include microbial sludge. In addition, if a proper amount of conveying and conveying in the lagoon-type long-term aeration tank, the pin flop is rarely generated, but it may occur due to an operation error.

In addition, the hardly decomposable organic material which has not been treated by aerobic oxidation in the sludge oxidizing tank 18 can be treated in an anaerobic contact tank.

In addition, the sludge introduced into the sludge oxidative decomposition tank 18 may come from the above-mentioned sedimentation and oil and water separation tank 14, may also come from the settling tank 17 to be described later.

Next, the wastewater treated in the second anaerobic tank 15 is in a substantially purified state. The second anoxic tank 15 is a denitrification tank, and unlike the first anoxic tank described above, there is no external carbon source supplied by itself. Therefore, this denitrification tank must be supplied with an external carbon source used for denitrification. In addition, this denitrification tank is a state in which the wastewater is considerably purified, and there is a shortage of internal carbon sources used for denitrification. Therefore, the microorganisms are denitrified by using the external carbon source supplied in the endogenous breathing step.

The wastewater overflowed from the second oxygen-free tank 15 is finally adsorbed and decomposed in the suspension microbial contact oxidation tank (contact aeration tank) 16 having a conventional structure. At this time, in the lagoon-type long-term aeration tank, the pin floc, which is sometimes generated due to an unbalanced operation of sludge withdrawal, wastewater inflow and oxygen, can be removed.

Lagoon type aeration tank used in the present invention has a sufficient buffering capacity against load fluctuation compared to the aeration tank used in the conventional method, even if the load fluctuation is not sufficiently handled in the lagoon type aeration tank, the contact aeration tank (16) ), It is possible to obtain steady and clean effluent quality by highly treating wastewater. In addition, as much as untreated organic pollutants remain, the microorganisms of the contact aeration tank 16 are used to remove phosphorus from the wastewater of the contact aeration tank 16 using phosphorus necessary for cell synthesis. At this time, it is usually operated at a dissolved oxygen concentration of 3-5 mg / l for efficient removal of phosphorus. In addition, in the microbial contact oxidation tank, the suspension growth and adhesion growth of the microorganisms are performed at the same time, but in the microbial contact oxidation tank of the present invention, the concentration of the suspended microorganisms (MLSS; Mixing Liquor Suspended Solid (MLSS)) is low and in the tank. High light transmittance So, in the summer, green algae grow on the top.

The wastewater thus treated is overflowed and sent to the settling tank 17. In the settling tank 17, the sludge settles to the bottom and the supernatant liquid is purified so that it may be discharged. Sludge precipitated in the settling tank 17 may be removed or transferred to the sludge oxidizing tank 18 for oxidative decomposition.

The supernatant of the settling tank 17 overflows and is finally transported to the defoaming and effluent tank for treatment and then discharged.

Now, another embodiment corresponding to a modification of one embodiment of the present invention described above will be described with reference to FIG. Another embodiment of the present invention described in Figure 6 is to improve the phosphorus removal efficiency more than the above embodiment.

As shown in Fig. 6, another embodiment of the present invention is almost the same as the above embodiment, but shows a difference in the following points. That is, in order to improve the efficiency of phosphorus removal, the microorganisms (sludge) are removed and removed in a timely manner from the lagoon-type long-term aeration tank, the lagoon-type aeration tank is used instead of the sludge oxidizing tank, and the feedback structure of other wastewater is used. . In fact, the sludge oxidative decomposition tank used in the above may be composed of a conventional long-term aeration tank or may be composed of a lagoon-type aeration tank used in the present invention. In this embodiment, the lagoon type aeration tank is used as the sludge oxidative decomposition tank, and the difference from the first embodiment is in the sludge withdrawal for improving the feedback structure and the phosphorus removal efficiency.

As described above, in the lagoon-type long-term aeration tank of the present invention, as the microorganism goes to the endogenous growth stage, the floc formation is better, the sedimentability is better, and the cell volume is reduced, but the phosphorus removal efficiency may be lowered by the microorganism releasing phosphorus again due to self oxidation. Has the potential problem. In order to solve this, the lagoon type aeration tank (# 1) releases phosphorus again due to excessively long microbial retention time, and removes and removes some of the microorganisms before the pin floc occurs. The removed microorganisms (sludge) are concentrated in a concentration tank and then transferred to a sludge storage tank, which is then dehydrated and removed.

Withdrawal of microorganisms from the lagoon type aeration tank (# 1) may be performed as a follow up when a pin floc without sedimentation occurs due to excessively long microbial retention time, as described above, It is preferable to predict the microorganism residence time beforehand. By taking out the microorganisms, the microbial residence time is adjusted low and the F / M ratio is adjusted to achieve a quick action for the pin floc phenomenon, and also prevent the occurrence of pin flocs in advance.

As described above, in the present invention, the first lagoon type long-term aeration tank operates at a level similar to the F / M ratio of the conventional long-term aeration method in order to exclude re-dissolution of phosphorus and occurrence of pin floc. In addition, the sludge is taken out from the first lagoon type long-term aeration tank at a suitable time to shorten the microorganism (sludge) residence time. As a result, the microorganisms ingesting phosphorus in the first lagoon type long-term aeration tank do not elute phosphorus again as the residence time increases, and there is no pin floc. For this purpose, the F / M ratio of the first lagoon type long-term aeration tank is usually maintained in the range of 0.05 to 0.1.

In addition, with the removal of some microorganisms, the wastewater from the lagoon-type long-term aeration tank (# 1) is transferred to the next joining suspension microbial contact oxidation tank (contact aeration tank) and at the same time, the part is transferred for feedback to the lagoon-type aeration tank (# 2). do. Wastewater transferred to the lagoon-type aeration tank # 2 is fed back to the denitrification tank via the lagoon-type aeration tank # 3. At this time, in the lagoon-type aeration tanks # 2 and # 3, the organic matter of the waste water is further oxidized, and the organic nitrogen and the ammonia nitrogen are further denitrified. This denitrified nitrogen component is nitrided in the denitrification tank and released to the atmosphere as nitrogen. In the lagoon-type long-term aeration tank (# 1), since a considerable amount of microorganisms have been removed from the lagoon-type long-term aeration tank (# 1), the microorganism residence time is shorter, so there is no occurrence of phosphorus elution and pin floc.

On the other hand, the additional lagoon type aeration tanks # 2 and # 3 operate at a lower F / M ratio and a higher microbial retention time (SRT) than the first lagoon type aeration tank. The additional lagoon aeration tank can have a higher microbial retention time by operating at a lower F / M ratio, thereby further oxidizing the wastewater without fear of floc dissolution and the occurrence of pin flocs. In the present invention, the additional lagoon type aeration tank can typically be operated at an F / M ratio of 0.01 to 0.05. The method of the present invention operates by adjusting the F / M lower from the first lagoon type aeration tank to the additional lagoon aeration tank and from the second lagoon aeration tank to the third lagoon aeration tank. This can improve problems such as the generation of non-sedimentable suspended solids due to the dissolution of flocs, the decrease in phosphorus removal efficiency caused by re-elution of phosphorus as the SRT becomes longer after the intake of microorganisms, and the pin floc caused by long SRTs. Can be. The number of additional lagoon-type aeration tanks used in the present invention may be many to reliably oxidize wastewater without the above problems, but one or two may be suitable in consideration of economic efficiency.

As shown in FIG. 4, the microorganism is extracted from the sedimented sludge (microorganism) to the outside instead of stirring the sludge (microorganism) settled by the solid / liquid separation baffle installed in the lagoon-type long-term aeration tank (# 1) with the wastewater. Can be achieved by withdrawing.

In FIG. 6, the transfer from the lagoon-type long-term aeration tank # 1 to the contact aeration tank is shown to be naturally transferred by an overflow. Instead, the lagoon-type aeration tank # 1 is replaced by the lagoon-type aeration tank # 2, # 3. ) And transfer the lagoon type aeration tank (# 1) to the lagoon type aeration tank (# 2, # 3) by overflow, and overflow the wastewater from the lagoon type aeration tank (# 3) to the contact aeration tank. It is also possible to feed back to the denitrification tank at the same time. The amount of wastewater fed back is preferably about 150-250% of the amount of wastewater fed in series.

On the other hand, in the process schematic diagram of Figure 6 there is no additional denitrification tank between the lagoon-type long-term aeration tank (# 1) and the contact aeration tank, because the nitriding and denitrification is effectively achieved by the improved feedback structure is unnecessary additional denitrification tank. . However, for more certain denitrification, an additional denitrification tank may be placed between the lagoon type long aeration tank (# 1) and the contact aeration tank. As described above, in the additional denitrification tank, unlike in the first denitrification tank, an external carbon source is supplied and denitrification occurs in the endogenous breathing step of the microorganism.

Table 1 below illustrates the operating conditions for each process of the wastewater treatment apparatus according to the embodiment.

Table 1

Lagoon-style aeration tank Contact Aeration Tank Anaerobic Contact Tank Denitrification tank HRT (hr) 60 12 24 2.5 Temperature (℃) Room temperature (10-30) Room temperature (10-30) 20-35-55 More than 20 DO (mg / l) 2-5 2-5 0.1 or less 0.1 or less MLSS (mg / l) 4,000 ~ 8,000 800-1,800 5,000-10,000 4,000 ~ 8,000 SRT (day) 10 ~ 90 (10 ~ 15) 3 ~ 10 over 10 BOD load (kg / m ³ ) 0.2-0.5 0.3 ~ 0.6 F / M ratio (kg / kg) 0.01 ~ 0.1 0.2-0.4 Internal circulation (%) 150-250 Final sedimentation sludge 150-250 VS Load (kg / m ³ ) 0.5-5

In the table, HRT is wastewater residence time, DO is dissolved oxygen amount, MLSS is sludge (microbial) amount, BOD is biological oxygen demand, SRT is sludge (microbial) retention time, F / M ratio is organic matter (nutrient source) / microorganism in wastewater The ratio and VS represent volatile solids, respectively. At the temperature of the anaerobic bath, 20-35-55 represents the optimum temperature of low temperature microorganisms, mesophilic microorganisms and high temperature microorganisms, respectively. The values in parentheses in the SRT of lagoon-type aeration tanks represent the optimal SRT of the first lagoon-style aeration tank for phosphorus removal.

On the other hand, Figure 7 shows a graph comparing the microorganism growth curve for the lagoon-type long-term aeration method used in the present invention with those for the standard activated sludge method and conventional long-term aeration method. As shown in Figure 7, the lagoon-type long-term aeration method used in the present invention by connecting a plurality of aeration tanks in parallel or in series by sequentially adjusting the low F / M ratio and high SRT by various growth stages of microorganisms in each aeration tank (Logistic growth stage, declining growth stage, and endogenous growth stage) are used appropriately, and the final aeration tank uses the more mature endogenous growth stage. Thereby, the reduction of sludge generation, the removal rate of nitrogen component, and the removal rate of phosphorus component can be achieved.

Hereinafter, an experimental example of treating wastewater using the wastewater treatment apparatus of the present invention described above will be presented.

Experimental Example

In order to treat the wastewater from the aquatic animal processing facility (squid squid, washing, seasoning) in Yangyang-gun, Gangwon-do, the wastewater treatment apparatus according to the first embodiment of the present invention described above was installed in a secret state. . The treatment capacity of the wastewater was 50 m ³ / day. The results obtained by this experiment are shown in Table 1 below. In addition, a comparison with the result of treating the wastewater by the conventional chemical treatment and the standard activated sludge method is shown in Table 2 below.

TABLE 2

Comparison of wastewater (raw water) and treated water (discharged water) obtained by the present invention

Item Raw water (ppm) Treated water (ppm) COD 2000 14 BOD 2500 8 S S 1700 8 T-N 300 18 T-P 28 5 Power consumption 350KW / day Drug consumption Nil Sludge Generation Nil

TABLE 3

Comparison of treated water (discharged water) obtained by the method of the present invention and the existing method

Item Method of the invention Chemical treatment + standard activated sludge COD 14 PPM (Almost Schedule) 12-180 (65) PPM (variable) BOD 8 PPM (almost schedule) 6-160 (55) PPM (variable) S S 8 PPM (almost schedule) 8-200 (60) PPM (variable) T-N 18 PPM (almost schedule) 60-160 (95) PPM (variable) T-P 5 PPM (almost schedule) 4-11 (5) PPM Power consumption 350KW / day (14,000 won / day) 350KW / day (14,000 won / day) Drug consumption Nil (65,000 won / day) Sludge Generation Nil 0.5 tons / day (25,000 won / day) Facility Investment Cost 80 million won (75%) 100 million won (100%)

In the table, T-N and T-P represent the total nitrogen content and the total phosphorus content, respectively.

As shown in Tables 1 and 2, the quality of the effluent water obtained by the wastewater treatment apparatus of the present invention was very good, it was confirmed that the present invention can obtain a steady effluent water quality compared to the existing method.

As described above, in the wastewater treatment apparatus and method of the present invention, except for one flow regulating submersible pump and a blower installed in the sump tank 11, there is no need for a machine, so the running cost is low. Therefore, it is efficient in terms of operating cost when applied to large scale as well as small scale. In addition, there is no chemical consumption, little sludge generation, and no pin floc to generate steady water quality.

For example, with respect to the initial investment and operating costs for aquatic wastewater treatment, the initial investment is similar to or slightly cheaper than the existing method combining chemical treatment and standard activated sludge method, and about 86% in terms of management convenience and operation cost. Can reduce the cost. For example, aquatic product companies that discharge 50 tonnes of effluent a day have benefited from saving about KRW 31 million per year and the labor costs of at least one heavy worker.

Claims (25)

Sealed anaerobic contact tanks, A first anoxic tank (denitrification tank) connected to the anaerobic contact tank by the discharge pipe of the anaerobic contact tank, A first lagoon-type long-term aeration tank connected to the first anaerobic tank, Suspension microbial contact oxidation tank (contact aeration tank) connected to the first lagoon-type long-term aeration tank, A sludge oxidizing tank connected to the lagoon-type long-term aeration tank for oxidatively decomposing wastewater including sludge received from the lagoon-type long-term aeration tank, and It comprises a precipitation tank connected to the suspension microbial contact oxidation tank, In the above, a part of the wastewater entering the first lagoon-type long-term aeration tank is fed back to the first anaerobic tank Wastewater treatment device. The method of claim 1, And a second anoxic tank (denitrification tank) is interposed between the first lagoon type long-term aeration tank and the microbial contact oxidation tank. The method of claim 1, The sludge oxidation cracking tank is one or more additional lagoon-type aeration tanks, and the wastewater fed back from the first lagoon-type long-term aeration tank to the first anoxic tank passes through the additional lagoon-type aeration tank from the first lagoon-type aeration tank to the first anoxic tank. Waste water treatment apparatus characterized in that the feedback. The method of claim 1, The sludge oxidation cracking tank is one or more additional lagoon-type aeration tanks, and the first lagoon-type aeration tank and the additional lagoon-type aeration tank are connected to each other and the wastewater of the first lagoon-type long-term aeration tank overflows and is transferred to the additional lagoon-type aeration tank. And the additional lagoon-type aeration tank has a structure in which a portion of its wastewater is fed back to the first anoxic tank and at the same time a portion overflows and is transferred to the microbial contact tank. The method of claim 1, Wastewater treatment, characterized in that the wastewater fed back from the first lagoon-type long-term aeration tank is fed back to the first anoxic tank directly from the first lagoon-type long-term aeration tank by air blowing. Device. The method of claim 1, The wastewater treatment apparatus further includes a sludge storage tank, and the sludge storage tank stores the wastewater for discharging the sludge (microorganism) drawn out from the first lagoon type long-term aeration tank. The method of claim 1, Wastewater treatment apparatus having a structure for feeding back the sludge precipitated in the settling tank to the anaerobic contact tank by blowing an air lift. The method of claim 1, Wastewater treatment apparatus characterized in that the sludge deposited in the sedimentation tank has a structure for transporting and treating the sludge oxidative decomposition tank. The method of claim 1, A waste water treatment apparatus which is characterized in that the anaerobic contact Joe anaerobic microorganisms attached reticulated charge of filter medium (media) that is formed at a predetermined interval, a baffle (baffle) to facilitate the flow of waste water is formed. The method of claim 9, The anaerobic contact tank is an wastewater treatment apparatus, characterized in that the inner sludge circulator is installed to prevent the filling medium is blocked by sludge. The method of claim 1, The discharge pipe of the anaerobic contact tank is a T-shaped pipe, and has a first end submerged in the waste water, a second end located above the level of the waste water, and a third end located in the first anoxic tank, so that the waste water and anaerobic Waste water treatment apparatus characterized in that the gas generated by the microorganism can be transferred together to the first anoxic tank. The method of claim 1, The apparatus further comprises injecting the gas generated in the anaerobic contact tank into the wastewater of the anaerobic contact tank and agitating the wastewater by the injection gas, wherein the generated gas is injected into the wastewater by the device to the anaerobic contact tank and the first Waste water treatment apparatus characterized in that it is transferred with the waste water from the anaerobic contact tank to the first anaerobic tank through a pipe connecting the anoxic tank. The method of claim 12, In order to adjust the temperature of the wastewater of the anaerobic contacting tank to the low, medium, and high temperature according to the variation of the inflow wastewater, a heating device using a high frequency induction current for heating the generated gas collected on the upper part of the anaerobic contacting tank and to be injected into the wastewater. Waste water treatment apparatus further comprising. The method of claim 1, The first lagoon-type long-term aeration tank is formed with a baffle serving as a sedimentation tank at the position where the waste water overflows and is transferred from the lagoon-type long-term aeration tank to the next tank, and a gap is formed at the bottom of the baffle. a waste water treatment apparatus, characterized in that the sludge settled is that exit into the gap process is mixed with the waste water lagoon of the expression long-term aeration tank. Supplying the wastewater to an enclosed anaerobic contacting tank with inlet and discharge piping, treating the wastewater by anaerobic microorganisms in the anaerobic contacting tank, and treating the wastewater treated in the anaerobic contacting tank in the anaerobic contacting tank Transporting the waste water with the gas generated by the anaerobic microorganism to the first anoxic tank (denitrification tank) through the discharge pipe, treating the wastewater in the first anoxic tank, and overflowing the wastewater treated in the first anoxic tank to overflow. Feeding the first lagoon-type long-term aeration tank by the step; treating the wastewater in the first lagoon-type long-term aeration tank; and feeding back a portion of the wastewater treated in the first lagoon-type long-term aeration tank to the first anaerobic tank. Transporting the wastewater treated in the first lagoon type long-term aeration tank to a suspension microbial contact oxidation tank. The step, and the wastewater treatment method comprising the step of transferring the wastewater treated in the suspension microbial contact oxidation tank by overflow to the sedimentation tank. The method of claim 15, Wastewater treatment method characterized in that between the first lagoon-type long-term aeration tank and the microbial contact tank through a second anoxic tank (denitrification tank) endogenous respiration of the microorganism and an additional denitrification step by an external carbon source. The method of claim 15, The step of feeding back the first lagoon-type long-term aeration tank to the first anoxic tank is characterized in that the wastewater of the first lagoon-type long-term aeration tank is further oxidized in a sludge oxidizing tank and then transported to the first anoxic tank. Treatment method. The method of claim 15, As the sludge (microbial) residence time (SRT) in the first lagoon-type long-term aeration tank increases, the sludge (microorganism) is withdrawn from the first lagoon-type long-term aeration tank before elution of pin floc and phosphorus occurs. Wastewater treatment method characterized in that. The method of claim 17, The sludge oxidizing tank is one or more additional lagoon aeration tank, the first lagoon long-term aeration tank and the additional lagoon aeration tank is operated in the F / M ratio range of 0.01 ~ 0.1, the additional lagoon aeration tank in the first lagoon long-term aeration tank Wastewater treatment method characterized in that the lower the F / M ratio. The method of claim 19, The F / M ratio of the first lagoon-type long-term aeration tank ranges from 0.05 to 0.1, and the F / M of the additional lagoon-type aeration tank is 0.01 to 0.05. delete The method of claim 17 , Sludge precipitated in the settling tank further comprises the step of feeding back to the anaerobic contact tank through the sludge oxidation cracking tank. The method of claim 15, The gas generated in the sealed anaerobic contacting tank is injected into the wastewater of the anaerobic contacting tank and stirred to increase the wastewater decomposition efficiency of microorganisms in the anaerobic contacting tank, and the generated gas is discharged along with the wastewater through piping of the wastewater of the anaerobic contacting tank. 1 Wastewater treatment method characterized in that the transfer to the submerged pipe. The method of claim 23, wherein In order to properly treat the incoming wastewater according to the fluctuation of the inflow wastewater flowing into the anaerobic contacting tank, the generated gas collected on the upper part of the anaerobic contacting tank and to be injected into the wastewater is heated using a high frequency induction current. Wastewater treatment method. The method of claim 15, The anaerobic contact tank is provided with a T-shaped pipe having a first end located in a space in which the generated gas is collected, a second end submerged in waste water, and a third end located in the first anoxic tank, and the generated gas being provided in the anaerobic contact bath. Waste gas treatment method characterized in that the by-product pressure is naturally transferred to the first anoxic tank with the waste water.