KR20000072808A - Waste Water Disposal System And Method - Google Patents

Abstract

PURPOSE: A wastewater treatment system is provided, which is characterized in that the system is combined with an anaerobic contactor, an extended aerobic lagoon and a microorganism-oxidizing contactor. The system has the advantages such as the decreases of generated sludge amounts and demanded chemicals amounts, economic cost for operation and steady water qualities. CONSTITUTION: A wastewater treatment system is composed of the following parts: a grit removal tank(10); a flow equalization tank(11); an anaerobic contactor(12) with 0.3kg/cm¬2 of gas pressure; a first anoxic zone(13) flowed partly feedback water from an extended aerobic lagoon(14); the extended aerobic lagoon(14) with 0.01-0.005 of F/M ratio packed with shaped-net media and installed with a baffle to flow smoothly; a second anoxic zone(15); an aerobic contactor(16); a settling tank(17); a sludge-oxidizing contactor(18); and a gas collection and dissolution facility.

Description

Wastewater Treatment System and Method {Waste Water Disposal System And Method}

The present invention relates to a wastewater treatment apparatus and method, and more particularly, to an anaerobic contact tank, an aerobic lagoon-style aeration tank, and a suspension microbial contact oxidation tank, together with one sedimentation tank, using a wastewater treatment apparatus and the wastewater treatment apparatus. A method of treating wastewater.

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 residence time (SRT), lack of dissolved oxygen (DO), and high F / M (Food / Microbe) ratio cause unbalance in the aeration tank due to overload of 80-90% of water deterioration 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 cost of wastewater treatment, high denitrification efficiency and consistently good discharge water quality, structure of apparatus or system It is to provide a waste water treatment device that is simple to manage.

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 high concentration of organic wastewater using the wastewater treatment apparatus of the present invention.

2 is a schematic view showing a wastewater treatment apparatus 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.

* Description of the main parts of the drawing.

10. Sedimentation and oil and water separation tanks

12. Anaerobic Contact Tank 13. Denitrification Tank (Anoxic Tank)

14. Lagoon type aeration tank 15. Denitrification tank (anoxic tank)

16. Contact aeration tank 17. Sedimentation separation tank

18. Sludge Oxidation Tank 19. Gas Collection and Dissolution Facilities

The wastewater treatment apparatus of the present invention has an inlet pipe and an outlet pipe, a closed anaerobic contact tank, a first anoxic tank (denitrification tank) connected to the anaerobic contact tank by the discharge pipe of the anaerobic contact tank, and a lagoon connected to the first anoxic tank. A long-term aeration tank, a second anoxic tank (denitrification tank) connected to the lagoon-type long-term aeration tank, a suspension microbial contact oxidation tank (contact aeration tank) connected to the second anoxic tank, connected to the lagoon-type long-term aeration tank received from the lagoon-type long-term aeration tank A sludge oxidizing tank for oxidatively decomposing wastewater containing sludge, and a precipitation tank connected to the suspended microbial contact oxidation tank. In the above, a part of the wastewater entering the lagoon-type long-term aeration tank is fed back to the first anoxic tank, and the wastewater entering the sludge oxidative decomposition tank is fed back to the anaerobic contact tank after being treated.

The lagoon-type long-term aeration tank is formed with a net-shaped media with anaerobic microorganisms attached at predetermined intervals, and a baffle is formed to smooth the flow of wastewater. At this time, the internal sludge circulator is installed to prevent the filling material is blocked by the sludge.

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 The gas generated by the microorganisms may be transferred together to the first anoxic tank. At this time, the gas pressure of the anaerobic contact tank can maintain 0.3 kg / cm ² or more. In particular, the anaerobic contact tank is preferably installed in the basement surrounded by a thermal insulation material in order to prevent excessively lowering the temperature below the proper temperature in winter, and to maintain the gas pressure of 0.3 kg / cm ² or more.

In the lagoon-type long-term aeration tank, the F / M ratio of the wastewater treatment is preferably maintained in the range of 0.01 to 0.005, and is operated while the aerobic microorganism is at the highest endogenous growth stage.

In addition, the present invention provides a method for treating high concentration of organic wastewater using the wastewater treatment apparatus.

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

1 is a flow chart showing a process for treating high concentration of organic wastewater using the wastewater treatment apparatus of the present invention. 2 is a schematic view showing a wastewater treatment apparatus of the present invention.

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 oxidizing 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.

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 treating the wastewater by the apparatus of the present invention, the wastewater treated in the anaerobic contacting tank 12 is transferred to the first tank, which is the next water tank, together with the gas generated therein. At this time, in order for the gas to be transferred, the gas pressure should be 0.3 kg / cm ² or more. And in order to maintain the gas pressure in the winter and to prevent excessively falling below the appropriate temperature (30 ℃), the anaerobic contact tank 12 is preferably installed in the basement surrounded by a heat insulating material.

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.

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. Aerobic microorganisms, on the other hand, are incapable of treating hardly degradable organic materials such as polymers, but are effective at decomposing moderately degraded organic materials. Therefore, in the present invention, by treating the anaerobic microorganisms and aerobic microorganisms continuously, it is possible to efficiently treat high concentrations of organic wastewater, particularly wastewater containing hardly decomposable organic matter.

In addition, ammonia nitrogen is 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. 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.

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 new tank developed by the present inventors by applying the concept of a long-term aeration tank using the lagoon method (lagoon tank) and the 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, if the microorganism residence time (SRT) is too long (usually more than 30 days), the microorganisms are degraded and a pin flop occurs. Since the floating matter caused by the pin-flop phenomenon is not precipitated in the sedimentation tank, the suspended solids are included as discharged water and thus discharged.

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 may expose the wastewater (microorganism) in the lagoon-type long-term aeration tank to about 60 to 96 hours, and even if the microorganism residence time is increased to about 60 days, the pin floc phenomenon does not occur. 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. The F / M ratio of the conventional long-term aeration method is about 0.03 to 0.05, whereas the F / M ratio of the lagoon-type long-term aeration method of the present invention is about 0.01 to 0.005.

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, in order to prevent the occurrence of the pin floc phenomenon, the waste water is returned to the anoxic tank 13 so that the pin floc phenomenon does not occur since the cell age and the microorganism residence time are substantially reduced. 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.

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, the nitrogen component thus nitrified can be denitrated through the return to the anaerobic tank 13 and the anaerobic contacting tank 12 through the sludge oxidizing tank 19, and the second step, the second anoxic tank (denitrification tank) ( 15) may be denitrified.

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.

On the other hand, in anaerobic contact tank, dephosphorus bacteria ingest the fermentation material and release phosphorus at the same time, and subsequently ingestion of phosphorus in the lagoon-type long-term aeration tank can additionally obtain phosphorus removal effect.

Next, the wastewater treated in the second anaerobic tank 15 is in a substantially purified state and 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.

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.

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 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 1

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 2

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 (11)

Sealed anaerobic contact tank, with inlet and outlet piping, A first anoxic tank (denitrification tank) connected to the anaerobic contact tank by the discharge pipe of the anaerobic contact tank, Lagoon-type long-term aeration tank connected to the first anaerobic tank, A second anoxic tank (denitrification tank) connected to the lagoon type long-term aeration tank, Suspension microbial contact oxidation tank (contact aeration tank) connected to the second anoxic 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 lagoon-type long-term aeration tank is fed back to the first anoxic tank, and the wastewater entering the sludge oxidative decomposition tank is fed back to the anaerobic contact tank after being treated. Wastewater treatment device. The method of claim 1, The lagoon-type long-term aeration tank is a wastewater treatment device is formed with a net-shaped filling medium (media) to which anaerobic microorganisms are attached, and a baffle is formed to facilitate the flow of wastewater. The method of claim 2, Wastewater treatment apparatus is provided with an internal sludge circulation device for preventing 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 that can transfer the gas generated by the microorganism to the first anoxic tank. The method of claim 4, wherein Waste water treatment apparatus for maintaining the gas pressure of the anaerobic contact tank 0.3 kg / cm ² or more. The method of claim 5, The anaerobic contact tank is installed in the basement in order to prevent the temperature from being excessively lowered below the appropriate temperature in the winter and to maintain the gas pressure of 0.3 kg / cm ² or more. The method of claim 1, Waste water treatment apparatus in which the F / M ratio in the lagoon-type long-term aeration tank is maintained in the range of 0.01 ~ 0.005. The method of claim 7, wherein The aerobic microorganism of the lagoon-type long-term aeration tank wastewater treatment apparatus is operated at the highest endogenous growth stage. The method of claim 1, The lagoon-type long-term aeration tank is formed with a baffle serving as a sedimentation tank at a position where the waste water overflows and is transferred from the lagoon-type long-term aeration tank to the second anoxic tank, and a gap is formed in the lower portion of the baffle to settle in the baffle. The sludge is discharged into the gap is mixed with the wastewater of the lagoon-type long-term aeration tank wastewater treatment apparatus. The method of claim 1, The sludge precipitated in the settling tank is fed back to the sludge oxidizing tank by an air lift, Transfer of wastewater from the first anaerobic tank to the lagoon-type long-term aeration tank, transfer of the wastewater from the lagoon-type long-term aeration tank to the second anoxic tank, and transfer of the wastewater from the second anoxic tank to the settling tank are caused by overflow. Has a structure that can be performed, Feedback of the wastewater from the lagoon-type long-term aeration tank to the first anoxic tank, transfer of wastewater from the lagoon-type long-term aeration tank to the sludge oxidative decomposition tank, and feedback of the wastewater from the sludge oxidative decomposition tank to the anaerobic contact tank are air lifts. Wastewater treatment apparatus carried out by. Supplying the wastewater to the sealed anaerobic contact tank with inlet and outlet piping, Treating the wastewater by anaerobic microorganisms in the anaerobic contacting tank, Transferring the wastewater treated in the anaerobic contacting tank to the first anoxic tank (denitrification tank) through the discharge pipe together with the gas generated by the anaerobic microorganisms in the anaerobic contacting tank, Treating the wastewater in the first anaerobic tank, Transferring the wastewater treated in the first anaerobic tank to a lagoon-type long-term aeration tank by overflow; Treating the wastewater in the lagoon type long-term aeration tank, Feeding back a portion of the wastewater treated in the lagoon type aeration tank to the first anaerobic tank, Transferring a portion of the wastewater treated in the lagoon type long-term aeration tank to a sludge oxidative decomposition tank, Transferring a portion of the wastewater treated in the lagoon type long-term aeration tank by overflow to a second anoxic tank, Treating the wastewater containing sludge in the sludge oxidizing tank, Feeding back the wastewater treated in the sludge oxidizing tank to the anaerobic contacting tank. Treating the wastewater in the second anaerobic tank, Transferring the wastewater treated in the second anoxic tank by overflow to a suspension microbial contact oxidation tank, and Wastewater treatment method comprising the step of transferring the wastewater treated in the suspension microbial contact oxidation tank by overflow to the settling tank.