KR100397168B1 - Apparatus and Method For Animal Waste water Treatment - Google Patents

Abstract

The present invention is to remove livestock waste water to be treated in the control tank after removing the contaminants, the tank is divided into high concentration livestock wastewater adjustment tank and low concentration livestock wastewater adjustment tank and equalizing the water quality of each wastewater; Injecting and mixing the high quality wastewater into the low concentration livestock wastewater adjusting tank and solidifying the mixed low concentration livestock wastewater to reduce the organic load; Injecting livestock wastewater with reduced organic load into a C / N ratio adjustment tank and adjusting the C / N ratio to be suitable for denitrification; Livestock wastewater from the C / N non-adjustment tank is injected into the first microbial reactor, and the day-to-day operation is divided into anaerobic and aerobic operations, and organic decomposition, nitrification, and denitrification reactions are maintained while maintaining the pH within the appropriate range. Removing organic matter and nitrogen in the livestock wastewater; Neutralizing and agglomerating the livestock wastewater treated in the first microbial reactor for solid-liquid separation and chromaticity and phosphorus removal; purifying the livestock wastewater by solid-liquid separation to remove livestock wastewater and removing color and phosphorus, and a part of the sludge Provided is a livestock wastewater treatment method and apparatus comprising the step of returning the treated water separated and returned to the first biological reaction tank.

Description

Livestock Wastewater Treatment Method and Apparatus {Apparatus and Method For Animal Waste water Treatment}

The present invention relates to a method and apparatus for treating livestock wastewater, which has a very high concentration of pollutants such as organic matter and nitrogen, and the quality of livestock wastewater fluctuates day by day and the fluctuations of water quality in seasons are very difficult to treat. It was difficult.

In particular, the nitrogen components contained in animal wastewater are present in ammonia nitrogen or organic nitrogen form depending on the season, temperature, and time of the livestock wastewater. Ammonia and organic nitrogen always exist in the form of coexistence, and the ratio of its presence changes from time to time, making it difficult to process stably.

Nitrogen in livestock wastewater is present in the form of organic nitrogen and inorganic nitrogen, and these are called total nitrogen (T-N). Inorganic nitrogen is again divided into ammonia nitrogen and nitrate nitrogen, and organic nitrogen and ammonia nitrogen are called TKN.

However, there is almost no nitrate nitrogen in the livestock wastes collected, and organic nitrogen and ammonia nitrogen occupy all of them, so the T-N and TKN values of livestock wastewater before collection and biological treatment are the same. Therefore, the value of TKN in the process before biological treatment will be simply used as the value of T-N and the display will be referred to as T-N.

Conventionally, only livestock wastewater is removed from the livestock wastewater, and is transferred to the microbial treatment tank as raw wastewater for biological treatment, or after removal of contaminants in the livestock wastewater, centrifugation is carried out again in a centrifuge to remove considerable amounts of organic matter and nitrogen. The load was reduced and then treated in a microbial treatment tank.

In the microbial treatment tank, organic matter and nitrogen in livestock wastewater are removed using the metabolic activity of microorganisms. In general, microbial treatment tanks are divided into aerobic and anaerobic operation periods for a certain period of time. and nitride is in progress and proceeds denitrification and organic matter decomposition during anaerobic operation period the nitrogen component in the livestock waste water is removed to the atmosphere is reduced to the N ₂ gas being this part of the organic matter is decomposed in accordance with.

However, if the raw wastewater is transported to the microbial treatment tank for treatment, the livestock wastewater quality is 30,000-35,000mg / l for sludge pigs, total nitrogen (TN) is 5,000-6,000mg / l, and the average degree of alkalinity is 10,000mg / l. The C / N ratio is about 6, which is higher than the C / N ratio required for nitrification and denitrification, but nitrification and denitrification are possible, but the organic load and nitrogen load are high, so the microbial treatment tank becomes larger in order to maintain the proper concentration for treatment. Facility costs are required and the area must be large.

In addition, the alkalinity is relatively low compared to the high nitrogen concentration, so when a large amount of alkalinity is consumed during nitrification (7.14 times the ammonia concentration), the pH of the microbial treatment tank is lowered and a large amount of alkaline agent is required to neutralize it.

If denitrification occurs completely, half of the pH consumed will be restored, but even in this case, the alkalinity consumed is about 17,800-21,420mg / l, and the alkalinity of the livestock wastewater is about 10,000mg / l. A large amount of alkali such as caustic soda should be used to maintain the pH above 7.0, a level suitable for nitrification.

In the case of biological treatment of livestock wastewater, the operation result shows that the SRT (sludge residence time) needs 40 to 60 days, and the MLSS concentration cannot be maintained above 30,000mg / ℓ considering the complete mixing or abandonment of the microbial treatment tank. As it is difficult, the hydraulic retention time of the microbial treatment tank is required 40 ~ 60 days, which is very large compared to the hydraulic retention time of the microbial treatment tank 10 ~ 15 days in the pretreatment process with a centrifugal separator. Done.

In addition, the aeration and complete mixing of the rich mixed solution requires about twice as much air and agitation power per unit volume of the treatment tank as compared to the pretreated microbial treatment process with the MLSS of 10,000 to 15,000 mg / l.

Therefore, when the raw wastewater is removed from only the contaminants and transferred directly to the microbial treatment tank, the microbial tank is large in size and requires a large land area and construction cost, and a lot of power is required to give up to maintain the aerobic treatment tank in aerobic and large amount of alkaline agent. As a result, the construction cost is high and the operating cost is high.

After removing contaminants in the livestock wastewater, the organic matter and nitrogen components are removed from the centrifuge, and the livestock wastewater is transferred to the microbial treatment tank for treatment. Although the construction cost is small, the C / N ratio of the livestock wastewater after centrifugation is not good because of the low C / N ratio.

Because organic nitrogen and BOD can be removed up to 70% by coagulation with a flocculant and mechanical method such as centrifuge, ammonia nitrogen is not removed by general flocculation method. In the treatment process, the concentration of nitrogen in the pretreated livestock wastewater is not constant and changes frequently. Especially, in summer, ammonia nitrogen accounts for about 70% of the total nitrogen, and the removal rate is very low even with flocculant. Nitrogen concentration in the livestock wastewater after pretreatment is very high and the BOD is relatively low, so the C / N ratio is very low, so denitrification after nitrification is not good, and the nitrogen removal effect is bad, and a large amount of alkaline agent is consumed during nitrification to lower the pH. To neutralize this, some amount of alkaline injection was required.

For example, when the ammonia nitrogen concentration is high in summer, the livestock wastewater with inflow BOD 20,000mg / l and TN 4,000mg / l is collected after coagulation in a centrifuge and the water quality of BOD 5,500 mg / l, TN 3,160 The mg / ℓ, alkalinity is about 8,000 mg / ℓ, and the C / N ratio is very low as 1.74, so it can be seen that the carbon source must be supplied from outside because it is not easily denitrified.

In addition, alkalinity consumed during nitrification is 7.14 × 3,160 × 0.9 = 20,306 mg / ℓ assuming that 90% of TN is converted to ammonia during nitrification, and denitrification is insufficient, so alkalinity is deficient over 10,000mg / ℓ and denitrification by external carbon source supply. Even if it is complete, 10,153 mg / L of alkalinity is required, and it is known that about 2,000 mg / L of alkalinity is insufficient. Correspondingly, the injection of an alkaline agent is required.

In addition, when the pH change in the nitrification and denitrification process was observed in the microbial treatment tank, the pH gradually increased with the onset of denitrification (anaerobic operation and wastewater supply). At the end of denitrification, the denitrification was terminated and the nitrification started. As the (aeration starts, aerobic operation), the pH gradually decreases and then decreases rapidly at a certain point and then decreases gradually to below 6.0.

However, since the nitrification rate becomes very slow at pH less than 7.0, it can be seen that in order to maintain the proper nitrification rate, an alkaline agent is injected into the microbial treatment tank to maintain the pH above 7.0.

However, even in the case of a livestock wastewater treatment facility, even if there is no alkaline injection device, it is required to inject into the agglomeration process of the centrifugal separator or the pressure flotation tank, which is a preliminary step of the microbial treatment tank. Since it is early, supplying wastewater with a high pH by injecting alkaline reagents in the denitrification process has caused the pH to become too high, which may interfere with microbial treatment.

In addition, in many cases, the methanol is not injected directly into the microbial treatment tank but directly into the pretreatment wastewater storage tank. In this case, the pretreatment storage tank is kept aerobic. Wasted.

In addition, when the solid-liquid separation of the biologically treated supernatant from the microbial treatment tank, the use of gravity sedimentation basin is high, so that the effective solid-liquid separation is difficult and the quality of the treated water becomes poor after separation.

In the case of using the pressure floatation tank for solid-liquid separation, it could not be effectively used due to the immaturity of the device design and manufacture, and even if used properly, the use of a pressurization facility and a high pressure (50 × 75m head) circulation pump for air dissolution And a large amount of circulating water and a floating tank with a capacity of about 2 hours of throughput is required. The device is also large, the required power is large, the power cost is high, and the accessory equipment for operating the pressure flotation device is relatively difficult. .

The treated supernatant in the microbial treatment tank has most of the organic and nitrogen components removed, but has very high chromaticity. When the treated water is connected to the sewage, the amount of wastewater discharged to the sewage is more than 1%. Color was included, which was visually unpleasant and caused complaints of the lower residents.

The technical problem to be achieved by the present invention is to equalize the water quality in the adjustment tank of livestock wastewater containing high concentration of organic matter and nitrogen, and reduce the pollution load of livestock wastewater through solid-liquid separator to effectively treat in small area treatment facility and to save external carbon source. The treatment process is configured to maintain the C / N ratio of the solid-liquid separated livestock wastewater without the use of denitrification, and the anaerobic and aerobic operation of the microbial treatment tank and the pH value generated during the treatment process. It is to provide a treatment method and apparatus that can effectively reduce nitriding and denitrification by preventing the degradation to maintain a proper pH during the treatment process, and to effectively remove the solid-liquid separation, color removal and phosphorus removal in the supernatant in the solid-liquid separator.

1 is a block diagram of a wastewater treatment method of the present invention.

Figure 2 is a graph showing the nitrogen removal effect according to an embodiment of the present invention.

Figure 3 is a graph showing the phosphorus removal effect according to an embodiment of the present invention.

Figure 4 is a graph showing the BOD removal effect according to an embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

1.Inlet

2. Dust removal device

3. High concentration livestock wastewater adjustment tank

4. Low concentration livestock wastewater adjustment tank

5. Solid-liquid Separator 1

6. Solid-liquid Separator 2

7. Fine solids removal device

8. C / N non-adjustment tank

9. First Microbial Reactor

10. Neutralization and flocculation device

11. Solid-liquid separation, chromaticity, phosphorus removal device

12. Return Sludge

13. Treatment water reservoir

14. pH adjusting device

15. Dewatering device

16. Linked processing device

17. Anaerobic Biofilter

18. Aerobic Bio Filter

19. Internal Circulation Water

20. Methanol injector

21. Separation Sludge

The present invention to achieve the above technical problem,

Dividing the livestock waste water to be treated into a high concentration livestock wastewater and a low concentration livestock wastewater into each adjustment tank to equalize the water quality and to separate the solids into liquids to adjust the concentration to be suitable for microbial treatment;

Adjusting the concentration of the livestock wastewater to a C / N ratio necessary for biological denitrification;

Adjust the concentration of the mixed solution so that the first microbial reactor has an appropriate F / M ratio, supply livestock wastewater with the C / N ratio adjusted in the anaerobic process, denitrify to remove nitrogen and some organic matter, and nitrify and remove organic matter in the aerobic process. Adjusting to maintain proper pH at all times during the process;

The livestock wastewater treated in the first microbial reactor was neutralized, coagulated and solid-liquid separated to remove solids, color, and phosphorus in the livestock wastewater, and a part of the sludge removed was returned to the first microbial reactor, and the treated water was connected to a sewage treatment plant. It provides a method for treating livestock wastewater comprising the step of transferring to a treatment facility or a separate second stage microbial reactor.

According to an embodiment of the present invention, the high and low concentration livestock wastewater adjusting tanks have a capacity of about 7 to 10 days, so that the change in organic matter and nitrogen concentration of the livestock wastewater fluctuating from day to day is small and solid-liquid separation step. It is preferable to use organic polymer coagulant in order to reduce the alkalinity in the livestock wastewater and to use the separated sludge as a compost raw material.

In the C / N ratio adjusting tank, it is preferable to maintain the BOD / T-N ratio at about 3 or more and adjust the BOD 7,500 to 10,000 mg / l and T-N 2,500 mg / l.

It is preferable to maintain the mixed liquid concentration of the first microbial reactor in the range of 10,000 to 20,000 mg / l, and the F / M ratio in the range of 0.03 to 0.04, and maintain the pH in the range of 7.0 to 9.0.

The pH adjusting agent includes sodium hydrogen carbonate, sodium carbonate and caustic soda, and is preferably added only during a period when the pH falls to 7.0 or less (mid and late nitrification).

In the coagulation, solid-liquid separation, color removal, and phosphorus removal step, it is preferable to use ferric chloride (FeCl ₃ , 38% solution) and cationic organic polymer as a coagulant.

In addition, the present invention to achieve the above technical problem,

High concentration livestock wastewater adjusting tank and low concentration livestock wastewater adjusting tank which separate and store the livestock wastewater to be treated as high concentration livestock wastewater and low concentration livestock wastewater, and equalize the water quality;

A solid-liquid separator comprising a device for supplying a flocculant to the livestock wastewater for removal of organic matter and nitrogen in the respective adjustment tanks;

A C / N ratio adjustment tank and an apparatus for storing the treated water discharged from the solid-liquid separator and injecting a portion of the high concentration livestock waste water to adjust the C / N ratio suitable for biological denitrification;

A floating growth type first microbial reactor for biologically treating the livestock wastewater discharged from the C / N non-adjustment tank and nitrifying and denitrifying by anaerobic operation and aerobic operation to remove organic matter and nitrogen;

An apparatus for measuring pH and supplying a pH adjuster to maintain the pH of the first microbial reactor in a range suitable for microbial growth;

DO (dissolved oxygen) concentration measuring device for monitoring the aeration and agitation device and anaerobic aerobic operation state for the anaerobic and aerobic operation of the first microbial reactor;

A flocculant supply device for supplying ferric chloride and a polymer flocculant to aggregate the treated water of the first microbial reactor in a state suitable for solid-liquid separation, color removal, and phosphorus removal, and the treated water of the first microbial reactor as sludge and treated water. Apparatus for conveying the sludge for separating the solid-liquid separation device for separation and the concentration of the mixed solution of the first microbial reactor; And

Provided is a livestock wastewater treatment apparatus including a treatment water storage tank having a neutralization device for discharging the treated water to an associated treatment facility or a second stage biological treatment facility.

Hereinafter, the present invention will be described in more detail.

1 is a process flow chart for explaining the livestock wastewater treatment method according to an embodiment of the present invention and will be described in detail below, but the following examples are numerous modifications are not necessarily limited thereto.

Livestock wastes collected from livestock farms can be classified into low concentrations of wastewater of less than 20,000mg / l and high concentrations of wastewater of more than 20,000mg / l of BOD. Currently, most livestock wastewaters are treated with high concentrations of livestock wastewater. There are many places where disposal by ocean dumping is carried out.

In addition, the livestock wastewater is 30 ~ 40% of water quality, which varies greatly depending on the day and season of collection.

In the case of the H group livestock wastewater treatment plant operated by the present inventors, the concentration of the high concentration livestock wastewater dumped by the livestock farms on average is BOD 55,000-65,000mg / l, SS 50,000-60,000mg / l, TN 6,000-7,000mg / l T-P 1,000 ~ 2,000 mg / ℓ and low concentration livestock wastewater flowing into the treatment plant have BOD 15,000 ~ 22,500mg / ℓ, SS15,000 ~ 20,000mg / ℓ, TN 2,800 ~ 4,200mg / ℓ, It is about T-P400-700 mg / L.

Since the collected livestock wastewater (1) contains a large amount of foreign matter such as animal hair, it is difficult to process it as it is, and then the debris removal device (2) first removes the contaminants, which are solid components, and the highly concentrated livestock wastewater concentration tank (3). If the low concentration wastewater is introduced into the low concentration livestock wastewater adjustment tank (4) and stored for about 7 to 10 days, the livestock wastewater quality, which varies greatly by about 30 to 40% per day, becomes homogeneous and is easy to treat.

The high concentration livestock wastewater of the high concentration livestock wastewater adjusting tank (3) is injected with a cationic organic polymer suitable for livestock wastewater at a rate of about 400 to 800 mg / l, and then agglomerated and separated by the solid-liquid separator (5). About 70 to 80% of the nitrogen content is transferred to the low concentration livestock wastewater adjusting tank 4 with 30 to 70% removed depending on the state, mixed with the low concentration livestock wastewater, and the mixed wastewater of the low concentration livestock wastewater adjusting tank 4 is When the solid-liquid separation after flocculation by the same method and concentration in the separator 6, the treated water quality after separation is BOD4,500-7,000mg / l, TN 2,000-3,200mg / l, TP 100-200mg / l, SS2,500 Maintain about 3,800 mg / l.

The relatively high T-N value after the solid-liquid separation and the large fluctuation is that ammonia nitrogen in the livestock wastewater is not removed during the solid-liquid separation.

For solid-liquid separators (5) and (6), it is preferable to use a model in which the amount of wastewater does not increase due to dilution or other water during the separation process. For this purpose, a centrifuge or an air flotation tank is suitable. High pressure air cleaning methods can be used, in which case the treated water quality is almost the same.

The treated water flows into the C / N ratio adjusting tank 8, but the treated water itself has a low C / N ratio, so that denitrification is poor in the first microbial reaction tank 9, which is a subsequent treatment process, so that nitrogen removal is insufficient. This is because biological denitrification requires about three times the amount of organic carbon of nitrified nitric acid, and the amount of nitrified nitric acid is equal to the TKN (= T-N) value of the livestock wastes, provided that nitrification is complete.

However, as described above, the concentration of livestock wastewater stored in the high concentration livestock wastewater adjusting tank 3 is, on average, BOD 55,000-65,000mg / l, SS 50,000-60,000mg / l, TN 6,000-7,000mg / l, T-P1,000 As the BOD / TN ratio is about 8 or more, the wastewater with high C / N ratio can be obtained by mixing some of the wastewater directly into the C / N ratio adjustment tank (8) and mixing it with the solid-liquid separated treatment water. It can be made easy.

Assuming the C / N ratio = BOD / TN ratio, let's say the high concentration livestock wastewater is X, and the solid waste separated livestock wastewater is Y, and the concentration of high concentration livestock wastewater is BOD 55,000mg / ℓ, TN 6,500mg / ℓ, SS50,000mg / Assuming that the concentrations of livestock wastewater separated from the solidified liquid after flocculation are BOD 5,750mg / ℓ, TN 2,600mg / ℓ and SS3,000mg / ℓ, the minimum required BOD / TN ratio is 3 and the daily wastewater treatment rate is 100㎥ / day. Assuming, the following relationship holds:

X + Y = 100 ㎥

(55,000X + 5,750Y) / (6,500X + 2,600Y) = 3

However, since Y = 100-X, we can get the following result by arranging the above equation.

X = 5.5, Y = 100-5.5 = 94.5 ㎥

The water quality after adjustment is as follows.

BOD 8,458 mg / l, SS 5,585 mg / l, T-N 2,814 mg / l, C / N ratio 3.0

The treated water quality after treating the wastewater with the BOD / TN ratio (= C / N ratio) set to 3 in the treatment apparatus as described above was very good as shown in Figs. It was very good.

In this way, if only low concentration livestock wastewater and high concentration livestock wastewater can adjust the C / N ratio (3 ~ 5) necessary for denitrification, biological denitrification can be effectively and economically performed without supplying expensive organic carbon sources such as methanol. can do.

The high concentration livestock wastewater in the high concentration livestock wastewater adjusting tank (3) still contains a considerable amount of animal hairs. It is preferable to remove from the removal device (7), and the fine solids removal device (7) increases the amount of waste water by using an air cleaning rotary mesh screen that removes foreign substances caught in the net by high pressure air to the continuous rotary fine mesh screen. Most preferred because it does not.

In the C / N ratio adjustment tank, when the organic matter in the livestock wastewater is decomposed, the C / N ratio is lowered. Therefore, it is necessary to maintain anaerobic. For this purpose, it is preferable to have a suitable mechanical stirrer. It is desirable to intermittently give up so as not to occur.

The livestock wastewater in which the C / N ratio is adjusted to an appropriate value in the C / N ratio adjusting tank is introduced into the first microbial reactor (9) to control the growth of microorganisms so that the MLSS concentration suitable for the quality of the livestock wastewater is adjusted. A part of the sludge generated in the phosphorus removing device 11 is conveyed to the first microbial reactor 9 as the conveying sludge 12.

According to the example of the operation result in actual facility;

The first microbial reactor (9) had a hydraulic retention time of 10 to 15 days, and was operated in a batch type that was repeated once a day, divided into anaerobic and aerobic operations due to the characteristics of the livestock wastewater, and the MLSS concentration was 12,000 to 16,000. When the mg / L, F / M ratio was operated at about 0.03 ~ 0.04 was good organic matter and nitrogen removal.

In the anaerobic operation, the operation of the aeration device in the first microbial reactor 9 is stopped, and a mechanical stirrer is operated to cause mixing, while maintaining the inside of the first microbial reactor 9 in the anaerobic state (= anoxic state) while maintaining the C / N When the livestock wastewater stored in the tank (8) is supplied within a short time and operated for about 4 to 6 hours, the nitrate nitrogen in the livestock wastewater is converted into nitrogen (N ₂ ) gas by the action of denitrification microorganisms and released into the atmosphere to be released into the atmosphere. And some organics are decomposed and removed simultaneously.

As denitrification proceeds, the pH in the first microbial reactor 9 gradually rises. In normal operation, a pH rise of about 1.5 to 2.0 occurs than before denitrification begins. The maximum pH ranged from 8.5 to 9.0, and this pH did not appear to have a significant effect on denitrification.

If the pH exceeds 9.0, it is necessary to inject hydrochloric acid to maintain the pH below 9.0.

When the denitrification process is completed, air is supplied to the aeration device in the first microbial reactor 9 to operate in an aerobic state of DO 2.0 mg / l or more and the operation time is about 18 hours.

In the aerobic state, decomposition of organic matter occurs and at the same time nitrification of ammonia nitrogen, which was originally present in the wastewater, and ammonia nitrogen from organic decomposition.

Nitrification of ammonia nitrogen consumes about 7.14 times the alkalinity of ammonia nitrogen, so the pH in the first microbial reactor 9 decreases with time. However, if the pH is less than 7.0, the nitrification rate is significantly lowered. In order to maintain the pH, the pH meter installed in the first bioreactor 9 was continuously monitored for pH change, and when the pH dropped below 7.0, sodium hydrogen carbonate (Na ₂ HCO ₃ ) or caustic was released from the pH adjusting device 14. An appropriate amount of alkaline agent such as sodium (NaOH) or sodium carbonate (Na ₂ CO ₃ ) should be injected to maintain the pH at about 7.0. In consideration of pH buffering performance, sodium hydrogen carbonate (Na ₂ HCO ₃ ) is more preferable.

The aeration device used in the first bioreactor 9 is a front aeration type aeration device using a microacid engine. In this case, an air diffuser that can be easily repaired by pulling the unit out of the tank immediately in case of failure or damage of the diffuser. It is preferable to use a device [designer of the present invention, a diffuser device for aeration tank (application number 1-1-1-01-5015532-84), a reverse flow prevention device for an acid pipe (application number 1- 1-01-5015533-29)]. Do.

The livestock wastewater having been treated in the first microbial reactor 9, that is, denitrification and nitrification is completed, is sent to the neutralization and flocculation apparatus 10, which is the next treatment, which includes a storage tank for temporary storage.

First, ferric chloride is injected into the coagulation tank, mixed with livestock wastewater, and then cationic organic polymer coagulant (polymer) is added, followed by stirring slowly for about 30 to 60 seconds, and solids, chromatic components, and toughness in the wastewater. The minute aggregates.

Scheme 1

_{FeCl 3 .6H 2 O + H 2} PO 4 + 2HCO 3 → FePO 4 ( precipitate) + 3Cl ^- + 2CO ₂ + O ₂ 8H

The amount of ferric chloride actually required is much higher than the ferric chloride required for the above reaction, because ferric chloride is consumed to react with alkali to form Fe (OH) _2, and phosphorus removal is good around pH 5.0-7.0. The color removal and solids separation were also good in the vicinity.

The aggregated livestock wastewater is sent to the solid-liquid separation and chromaticity and phosphorus removal device (11) to separate the sludge and the treated water.

In this treated water, almost all solids, colors and phosphorus were removed to obtain a very clean purified water.

FIG. 2 shows an example of changes in nitrogen content of influent wastewater and treated wastewater during a recent period of time which is normally operated under the conditions of the first microbial reactor using the above low concentration wastewater in an actual treatment plant. FIG. Example of change in minutes, Fig. 4 shows an example of change in BOD.

As shown in FIG. 2, the nitrogen removal efficiency is stably maintained at 95% or more since the C / N ratio is close to 3.0.

Phosphorus is removed by the flocculation reaction, so that the phosphorus component in the treated water is always maintained at less than 2.0 mg / l and shows a high removal rate of 99.7 to 99.8%.

The removal rate of BOD is stable more than 98%.

The chromaticity was not measured every day at the site, so when the sample was commissioned by an accredited test laboratory, the color of the supernatant treated in the first microbial reactor was 17,800 and the chromaticity of the solid-liquid treated water after flocculation was 301, which was 98.3%. Was showing.

Belt thickener is most suitable for solid-liquid separation, chromaticity and phosphorus removal device (11) in terms of economical efficiency and ease of operation. For example, a sufficient effect can be obtained and it is important not to increase the amount of treated water when reprocessing the treated water in a secondary biological treatment facility. Therefore, a high pressure air washing belt concentrator or an air flotation concentrate or centrifuge is used. It is preferable.

Here, a part of the concentrated sludge is sent to the first bioreactor 9 as a return sludge 12 for controlling and maintaining the MLSS of the first bioreactor 9, and the rest is dewatered or connected to the dehydration device 15. Dehydration treatment in the dehydrator of the.

The treated water is temporarily stored in the treated water storage tank 13 and can be adjusted to an appropriate pH according to the needs of the subsequent treatment process and is transferred to the next treatment facility.

In general, the final treatment of the treated water is usually linked to the sewage treatment plant. In this case, the treated water is transferred to the sewage treatment plant, mixed with the sewage, and finally discharged.

There is a case where the treated water is discharged by reprocessing secondaryly without being linked with sewage. In this case, the treated water is transferred to the second stage treatment facility.

However, the treated water quality is relatively high in nitrogen compared to BOD as indicated above, so in order to control the C / N ratio suitable for denitrification from the outside to supply an organic carbon source such as methanol.

The two-stage treatment of treated water is highly purified water free of contaminants, so it is easier to operate and has higher microbial concentration than general floating biotreatment facilities. The long time is very effective for nitrification and denitrification.

As the biological contact filter material, sand, anthracite, or synthetic resin balls having a diameter of 3 to 5 mm may be used, and it is desirable to use an economical and easily available sand filter.

An example of the configuration is that the anaerobic biofiltration apparatus 17 and the aerobic biofiltration apparatus 18 of FIG. 1 are arranged in series, and a part of the treated water of the aerobic biofiltration apparatus 18 is internally circulated to the anaerobic biofiltration apparatus 17. (19) The anaerobic biofiltration system (17) is injected with methanol about 2.5 to 3 times the amount of nitrate nitrogen nitrated in the methanol injection device (20) and operated in a continuous operation.

In addition, in order to prevent clogging of the biofiltration layer, the wastewater is preferably introduced in an upstream flow from the bottom of the biofiltration system, and air cleaning and water washing are periodically performed on the filter layer to maintain proper biomass and prevent clogging.

During treatment, the aerobic biofiltration system 18 does not require a separate pH control device because the amount of nitrogen in the waste water is small and the pH decrease is insignificant. Because you can respond by adjusting.

Another embodiment of adjusting the C / N ratio of the C / N ratio adjusting tank in the present invention is as follows.

The water quality of the low concentration livestock wastewater adjusting tank 4 after coagulation with the flocculant in the solid-liquid separator 6 is obtained as BOD 5,750mg / l, TN 2,600mg / l, SS3,000mg / If the level is maintained, the C / N ratio is 2.2, which is less than 3, which is the minimum required C / N ratio.

However, the livestock wastewater of the low concentration livestock wastewater adjusting tank 4 has a C / N ratio of about 5 to 6, so that a part of the livestock wastewater flows into the C / N ratio adjusting tank according to the C / N ratio adjusting method, and the solid-liquid separator (6). Mixing with wastewater separated from can produce wastewater with a C / N ratio of 3 or more.

The livestock wastewater of the low concentration livestock wastewater adjusting tank (4) can be transferred directly to the C / N ratio adjusting tank (8) by using a pump or the like. Another method is to use a centrifuge in a solid-liquid separator. When operating in a chemical-free state without a coagulant in the centrifuge, the water quality of the separation liquid is similar to the water quality before separation, and only some impurities are removed. The C / N ratio of the wastewater in the C / N ratio adjustment tank 8 can be adjusted to 3 or more by adjusting the value of.

According to an embodiment of the present invention, 95% of the inflow nitrogen component and 99 of the phosphorus component are required by only one-step treatment of solid-liquid separation, C / N ratio adjustment, first microbial reactor, solid-liquid separation and color, and phosphorus removal device by aggregation. It can be seen that more than 98% of chromatic components and more than 98% of BOD are stably removed.

According to the livestock wastewater treatment method of the present invention, it is possible to effectively and stably remove the high concentration of organic matter, nitrogenous component, phosphorus and color in the livestock wastewater treatment process. It is easy to operate and maintain, the processing site can be small, and the construction cost and operating cost are economical because no external carbon source is used in the denitrification process.

Claims (13)

A method of treating livestock wastewater, comprising: classifying livestock wastewater to be treated into a high concentration livestock wastewater and a low concentration livestock wastewater, inflowing into each adjustment tank to equalize the water quality, and separating the solids into solids to adjust concentrations suitable for microbial treatment; Adjusting the concentration of livestock wastewater to a C / N ratio necessary for biological denitrification; Adjust the concentration of the mixed solution so that the first microbial reactor has an appropriate F / M ratio, supply livestock wastewater with the C / N ratio adjusted in the anaerobic process, denitrify to remove nitrogen and some organics, and nitrify and remove organics in the aerobic process. Adjusting to maintain proper pH at all times during the process; And The livestock wastewater treated in the first microbial reactor was neutralized, coagulated and solid-liquid separated to remove solids, color, and phosphorus in the livestock wastewater, and a part of the sludge removed was returned to the first microbial reactor, and the treated water was connected to a sewage treatment plant. A method of treating livestock wastewater comprising the step of transferring the treatment facility or a separate second stage microbial reactor. The method of treating livestock wastewater according to claim 1, wherein the pH adjusting agent of the first microbial reactor includes sodium hydrogen carbonate and hydrochloric acid, and the pH adjusting agent is directly injected into the first microbial reactor according to the treatment process. The method according to claim 1, wherein a part of the wastewater separated from the solid-liquid separator using a flocculant and a portion of the high concentration wastewater of the high concentration wastewater adjusting tank are mixed in an appropriate ratio in the C / N ratio adjusting tank to adjust the C / N ratio to 3 or more. Livestock wastewater treatment method characterized in that. The method according to claim 1, wherein a part of the wastewater separated from the solid-liquid separator using a flocculant and a portion of the low concentration wastewater of the low concentration wastewater adjusting tank are mixed in an appropriate ratio in a C / N ratio adjusting tank to adjust the C / N ratio to 3 or more. Livestock wastewater treatment method characterized in that. The wastewater of the low concentration livestock wastewater adjusting tank is subjected to solid-liquid separation in a centrifugal separator, but the ratio of the time of operation with the flocculant and the time of operation without the flocculant is adjusted and put into the C / N ratio adjustment tank and mixed to mix the C / N. A method for treating livestock wastewater, comprising adjusting the ratio to three or more. The method for treating livestock wastewater according to claim 1, wherein the C / N ratio adjustment tank is anaerobic and mechanically stirred or intermittently aerated to prevent organic decomposition. The method according to claim 1, wherein the pH of the first microbial reactor is maintained at 7.0 to 9.0, which is suitable for denitrification and nitrification, and the MLSS is maintained at 10,000 to 20,000 mg / l. The method according to claim 1, wherein ferric chloride and a cationic organic polymer coagulant are used as flocculants for solid-liquid separation, color and phosphorus removal. The method of claim 1, wherein the solid-liquid separation, chromaticity, phosphorus-removed treated water is treated again through anaerobic filtration and aerobic filtration. High concentration livestock wastewater adjusting tank and low concentration livestock wastewater adjusting tank which separate and store the livestock wastewater to be treated as high concentration livestock wastewater and low concentration livestock wastewater, and equalize the water quality; A solid-liquid separator comprising a device for supplying a flocculant to the livestock wastewater for removal of organic matter and nitrogen in the respective adjustment tanks; A C / N ratio adjustment tank and an apparatus for storing the treated water discharged from the solid-liquid separator and injecting a portion of the high concentration livestock waste water to adjust the C / N ratio suitable for biological denitrification; A floating first microbial reactor for biologically treating the livestock wastewater discharged from the C / N non-adjustment tank and removing organic matter and nitrogen by nitrifying and denitrifying by anaerobic operation and aerobic operation; An apparatus for measuring pH and supplying a pH adjuster to maintain the pH of the first microbial reactor in a range suitable for microbial growth; DO (dissolved oxygen) concentration measuring device capable of monitoring the aeration device and agitation device and anaerobic aerobic operation state for the anaerobic and aerobic operation of the first microbial reactor; A flocculant supply device for supplying ferric chloride and a polymer flocculant to aggregate the treated water of the first microbial reactor in a state suitable for solid-liquid separation, color removal, and phosphorus removal, and the treated water of the first microbial reactor as sludge and treated water. Apparatus for conveying the sludge for separating the solid-liquid separation device for separation and the concentration of the mixed solution of the first microbial reactor; And Livestock wastewater treatment apparatus including a treatment water storage tank having a neutralizing device for discharging the treatment water to the associated treatment facility or the second stage biological treatment facility. 11. A livestock wastewater treatment apparatus according to claim 10, wherein the solid-liquid separator has a high-pressure air washing apparatus and a high-pressure water washing apparatus as an auxiliary washing means so that the amount of the separation liquid does not increase or only slightly increases. 12. The livestock wastewater treatment apparatus according to claim 10, wherein the aeration device of the first bioreactor is configured to allow the diffuser to pull out and repair the diffuser piping unit in the event of a failure. The method of claim 10, characterized in that the first treated wastewater is disposed in series with an anaerobic biofiltration unit and an aerobic biofiltration unit, and the anaerobic biofiltration unit is treated again in a treatment unit which allows the injection of methanol from the metaol supply unit. Livestock wastewater treatment device.