KR100714825B1 - Method for treating sewage and high organic loading wastewater by anaerobic/oxic process with membrane and biological aerated filter - Google Patents

Abstract

The present invention relates to a method for treating wastewater and high concentration organic wastewater, by treating a wastewater that has undergone a pretreatment step or a first biological treatment step through a combination of an anaerobic / aerobic reactor and an aerobic filter with a separator. And it relates to a wastewater and high concentration organic wastewater treatment method to efficiently remove phosphorus at the same time.

Centrifuge, Sludge, Ozone, Wastewater, Manure, Organics, Bioreactor, Aerobic Vapor

Description

METHODS FOR TREATING SEWAGE AND HIGH ORGANIC LOADING WASTEWATER BY ANAEROBIC / OXIC PROCESS WITH MEMBRANE AND BIOLOGICAL AERATED FILTER}

1 is a schematic diagram of a conventional high concentration organic wastewater treatment method.

2 is a process schematic diagram of a high concentration organic wastewater treatment method according to an embodiment of the present invention.

Figure 3 is a detailed process of the high concentration organic wastewater treatment method according to an embodiment of the present invention.

Figure 4 is a detailed process diagram of a high concentration organic wastewater treatment method according to another embodiment of the present invention.

5 is a plan view of a high rate microbial reaction stirrer used in the present invention.

6 is a longitudinal sectional view of the high rate microbial reaction stirrer of FIG.

* Description of symbols on the main parts of the drawings *

10: dust collector 12: water collector (pumping tank)

14 centrifuge 20 first flow adjustment tank

22: high rate microorganism reaction stirrer 26: second flow control tank

28: centrifugal dehydrator 50: resources

51: anaerobic tank

52: aerobic reactor combined with a separator

54: Aerobic Vaginal Vapor (BAF) 55: Ozone Tank

The present invention relates to a method for treating wastewater and high concentration organic wastewater, and more particularly, by treating wastewater that has undergone a pretreatment step and a first biological treatment step through an anaerobic / aerobic reactor combined with a separator and an aerobic filter. Disclosed is a method for treating wastewater and high concentration organic wastewater, which efficiently removes substances, nitrogen, and phosphorus simultaneously.

In general, organic wastewater is subjected to solid-liquid separation through screen separation, sedimentation separation, and the like, and is then treated in a manner of being discharged after biological treatment combining aerobic treatment, anaerobic treatment, and anoxic treatment.

As described above, the biological treatment in organic wastewater treatment removes various organic substances composed of carbon, which is a nutrient source of microorganisms dissolved in the wastewater, as well as nitrogen compounds, phosphorus compounds derived from lipids, and the like that are generated from decomposition of proteins. It is a process for following.

Hydrocarbons, which are nutrient sources of microorganisms, are relatively easily removed by microorganisms, but nitrogen and phosphorus compounds are not easy to remove, and researches for biologically removing them have been conducted for a long time.

The microbial treatment method for the removal of nitrogen compounds and phosphorus compounds known to date has shown some effects on the sewage generated from cities with relatively low content of organic nitrogen or ammonia nitrogen. However, in the case of livestock wastewater from rural livestock farms, the amount of sludge generated from livestock waste is excessively and continuously generated. Therefore, there is a problem that treatment facilities have to be enormous due to the increase of nitrogen compounds and the treatment time is prolonged. Therefore, the conventional microbial treatment method as described above has a limitation that can not be practically applied to high concentration organic wastewater, such as livestock wastewater.

Biological nitrogen removal is a method of continuously inducing cell synthesis, nitrification, and denitrification by the assimilation of microorganisms and converting them into nitrogen gas for removal. The ammonia nitrogen compound is converted into nitrate nitrogen by the oxidation of microorganisms such as nitrosomonas and nitrobacter. Subsequently, the nitrate nitrogen is changed from the oxygen-free state to the nitrogen gas state by the organic carbon source which is the electron donor by heterotropes, which are random heterotrophic microorganisms.

The process developed using the above principle is collectively called BNR (biological nutrient removal) process, which induces nitrification by maintaining aerobic inside of the reactor and denitrification of nitrified nitrogen compounds under anoxic conditions. do. Most of them rely on the arrangement of aerobic and oxygen-free reactors, and based on these BNR processes, research has been carried out, such as the Bardenpho process, A / O process, A2 / O process, University of Capetown (UCT) process, and Biodeny. Biodenipho (Biodenipho; Biological Denitrification Phosphorus) process, BB (Bunnik Bunschoten) process, Carrousel process, Oxidation ditch process, etc. have been developed.

However, although many processes have been developed for the treatment of biological nitrogen as described above, as mentioned above, the livestock manure produced by the mass farming of livestock farms, which requires a large area for processing facilities or contains a large amount of organic materials. The process still had many problems.

In addition, the technology for treating high concentration organic wastewater is often used on the basis of anaerobic, and when treating high concentration of organic livestock wastewater, aerobic oxidation process using a very high dilution ratio has been used. However, these devices are also expensive to process and require a large number of subsequent installations and a number of accessories to further remove nutrients. In addition, high concentration organic wastewater is one of the typical processes that is difficult to treat during water treatment because post-treatment is necessarily required to meet the effluent regulation even if treated with high efficiency.

As a high-efficiency anaerobic digestion method, a number of methods are known, such as UASB (Upflow Anaerobic Sludge Bed), AF (Anaerobic Filter), AEB (Anaerobic Expended Bed), and modified hybrid methods are stable. Anaerobic digestion is a process that blocks the process due to hardly decomposable particles due to the high organic load due to the high concentration of organic matter when large amounts of suspended solids are present in the wastewater or when manure and urine are not clearly separated, such as livestock wastewater. There are operational problems.

In addition, the aerobic oxidation process through dilution has a problem in that the overall process equipment is very large and the construction and operation management cost is very high because the design is made in accordance with the food to microorganism ratio and the load through a large amount of dilution. .

The present inventors include a pretreatment step, a first biological treatment step, a second biological treatment step, a chemical treatment step and a resource resource step as schematically shown in FIG. 1 in the domestic application 2005-10711 in order to overcome the above problems. A wastewater treatment method has been proposed. However, even with this method, there is a limit to efficiently remove nitrogen and phosphorus at the same time, and improvement is required.

The present invention has been made to overcome the problems of the prior art as described above, one object of the present invention is a combination of a biological treatment step, a bioreactor and an aerobic phase, such as wastewater after the pretreatment step, the first biological treatment step The present invention provides a method for treating wastewater and high concentration organic wastewater that efficiently removes suspended solids, nitrogen, and phosphorus at the same time.

Another object of the present invention is to provide a method for producing wastewater and high concentration organic wastewater which can efficiently use energy by increasing the content of methane gas in an anaerobic tank as the recycle ratio of the aerobic filter is increased.

One aspect of the present invention for achieving the above object is in the treatment of high concentration organic wastewater,

Pretreatment to filter out large contaminants in the wastewater;

A first biological treatment step of treating the pretreated wastewater with a high rate microbial reaction stirrer to decompose high concentrations of organic matter and nutrients contained in the wastewater;

A dephosphorization step of decomposing phosphorus in the wastewater by treating the wastewater treated in the previous step through an anaerobic / aerobic reactor combined with a separator;

Nitrifying the wastewater that has undergone the dephosphorization step through an aerobic filter and then returning to the first biological treatment step;

The present invention relates to a wastewater and high concentration organic wastewater treatment method comprising a third treatment step of ozonating denitrified wastewater.

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

2 is a schematic view of the treatment process of high concentration organic wastewater according to an embodiment of the present invention. The present invention efficiently combines an anaerobic / aerobic reactor and an aerobic phase combined with a membrane followed by a pretreatment step and a first biological step to achieve a process that can be applied to general purpose high concentration organic wastewater including livestock wastewater. Characterized in that the high concentration of wastewater can be treated.

In the method of the present invention, in the treatment of high concentration organic wastewater such as livestock wastewater, manure and food wastewater, a large contaminant in a high concentration wastewater is passed through a contaminant treatment machine 10, a pumping tank 12 and a centrifuge 14 in order. Pretreatment step (A) of filtering out and separating the sludge content containing the fine solid floatation; A first biological treatment step (B) of decomposing high concentrations of nutrients contained in the wastewater which has been subjected to the pretreatment step (A) using a high rate microbial reaction stirrer; A dephosphorization step (C ′) in which the wastewater passes through an aerobic tank and an aerobic tank combined with a separator in order to decompose phosphorus contained in the wastewater subjected to the first biological treatment step (B); A nitrification step (F) for nitrifying the wastewater through an aerobic filter in order to remove nitrogen contained in the wastewater subjected to the dephosphorization step (C ′) and then returning it to the first biological treatment step (B) for denitrification; And a third treatment step (G) through which the denitrified wastewater is subjected to an ozone treatment facility in order to decompose the hardly decomposable substance and chromaticity contained in the wastewater subjected to the nitrification step.

FIG. 3 together shows the treatment apparatus used in each step of the method for treating high concentration organic wastewater of the present invention shown in FIG. 2.

In the pre-treatment step (A) of the present invention, a fines treatment device 10 for filtering large contaminants, a water collecting device 12 for collecting and pumping wastewater filtered out of the contaminant processing device 10, and the wastewater are rotated to centrifuge small contaminants. The wastewater is treated via a centrifuge 14 for separation to filter out large contaminants in the wastewater.

Following the pretreatment step, in the first biological treatment step, the wastewater from which the contaminant is filtered is reacted with oxygen in the pretreatment step, and the sludge is separated from the high-rate microbial reaction stirrer for purifying the waste water using the microorganisms inside and the discharged water mixed with the microorganisms and the treated water. Treatment is performed using a centrifugal concentrated dehydrator.

In this case, as shown in FIG. 4, the first flow rate adjusting tank 20 and the second flow rate adjusting tank 26 may be provided at the front and rear ends of the high rate microbial reaction stirrer 22, respectively. In this case, the first biological treatment step (B) is a high rate of reacting the wastewater filtered out of the contaminants in the pretreatment step (A) with the first flow rate adjusting tank 20 and the wastewater with oxygen and purifying the wastewater using microorganisms inside. Through a microbial reaction stirrer 22, a second flow rate adjustment tank 26 for storing the discharged water treated in the high rate microbial reaction stirrer 22, and a centrifugal concentrated dehydrator 28 for separating the sludge from the effluent mixed with the microorganisms and the treated water. Proceed.

5 is a plan view of a high rate microbial reaction stirrer of a high concentration organic wastewater treatment apparatus according to the present invention, and FIG. 6 is a longitudinal sectional view of a high rate microbial reaction stirrer of a high concentration organic wastewater treatment apparatus according to the present invention.

Waste water supplied to the microorganism reaction stirrer 22 is treated through the denitrification tank 212, the activation tank 214, the nitrification tank 216 through the raw water inlet pipe 220 of FIG. 6, and discharged to the outside. The portion of is transferred internally from the nitrification tank 216 to the denitrification tank 212. The air is introduced into each reactor through the ejector 240 and the air inlet hoses 2123, 2143, and 2163 using the underwater air pumps 2121, 2141, and 2161 for a predetermined time to decompose organic matter and nitrify the ammonia nitrogen. Let's do it. In Figure 6, the ignition arrow shows the path that the treated water is moved.

After a certain period of time, the inflow of the denitrification tank 212 is blocked, and the inside is stirred using a submersible air pump to nitrify the nitric acid, which is transported inside, and denitrify using organic materials in the incoming raw water. After denitrification, air is introduced again and the process is repeated for a certain time.

In addition, sludge discharge ports 2125 and 2165 for discharging sludge are formed at the lower portions of the denitrification reaction tank 212 and the nitrification reaction tank 216.

Wastewater treated in the high rate microbial reaction stirrer 22 is subjected to a dephosphorization step as shown in FIGS. 3 and 4. In the present invention, the dephosphorization step (C ′) may more effectively remove the phosphorus component by treating the effluent after the first biological treatment step through an anaerobic / aerobic reactor combined with a membrane (MBR).

Specifically, the dephosphorization step may include an anaerobic tank 51 releasing phosphorus using dephosphorus microorganisms; Under aerobic conditions, the separation membrane 52 for absorbing phosphorus by using the dephosphorus microorganism proceeds through the combined aerobic reaction tank 52.

 The anaerobic tank 51 does not supply air to remove the phosphorus by releasing the phosphorus. The phosphorus content in the cells of the microorganism is about 1.5 to 2% by dry weight ratio, and the removal efficiency is low because phosphorus is removed only as necessary for cell synthesis. However, dephosphorus microbes release phosphorus in the anaerobic state and overingest more than phosphorus released in the aerobic state. Therefore, in the aerobic reaction tank, dephosphorus microorganisms exposed to aerobic conditions ingest phosphorus in excess to drastically lower the concentration of phosphorus in water, and then, by separating and discarding sludge ingested in excess, high phosphorus removal efficiency can be obtained.

In the present invention, a separator is installed in the aerobic reaction tank and subjected to microfiltration or ultrafiltration. In the present invention, the separation membrane may be a microfiltration membrane, an ultrafiltration membrane capable of retaining a high concentration of microorganisms in a reaction tank by perfect solid-liquid separation, and the like. The separation membrane separates the treated water and sludge treated in the aerobic reaction tank, and performs subsequent phosphorus removal with dense microorganisms.

According to the process, the solid-liquid separation and most organic matter are removed by the pretreatment step and the first biological treatment step, and phosphorus is removed through the anaerobic / aerobic process, while increasing the biochemical oxygen demand (BOD) and floating There is no fear of leakage of Suspended Solid (SS), and it is possible to realize optimum nitrification through aerobic filter and to remove organic matter and suspended solids at the same time.

Wastewater having passed through the dephosphorization step (C ′) is introduced into the nitrification step (F). The effluent flowing out of the anaerobic / aerobic reactor combined with the separator was removed a large amount of organic matter and phosphorus, but still contains a large amount of organic matter and nitrogen components. Therefore, by rapidly nitrifying the treated water through the aerobic filter (BAF) to remove the nitrogen component and returning to the first biological treatment step (B) containing a large amount of organic matter, organic and nutrients are returned. Remove efficiently

The aerobic filter was introduced into the upper portion of the filter bed filled with a contact filter of about 3 ~ 5 mm in the effluent through the anaerobic / aerobic reaction tank combined with the separation membrane and the nitrifying microorganisms attached to the surface of the filter medium while passing through the filter media It is a treatment method that allows microorganisms to simultaneously nitrify, decompose organic matter and capture suspended matter.

The supply of oxygen necessary for the oxidation and assimilation of microorganisms takes place from the diffuser in the bottom of the filter bed. Since the image is closed by the suspended solids and the grown microorganisms with the passage of the treatment time, backwashing with air or water is performed to restore the filtration function.

The nitrification step (F) increases and decreases the ratio of the recycled water of the treated water discharged from the aerobic filter to adjust the ratio of the inflow and the recycled flow rate to 1: 1 to 1: 3, whereby the methane generation rate of the high rate microbial stirrer is 60. It is preferable to make it from% to 90%. In this case, as the recycle ratio of the treated water is increased, the content of methane gas discharged from the first biological treatment step (B) increases, thereby making it possible to use energy more efficiently.

The combination of the dephosphorization step by the anaerobic / aerobic reactor combined with the separator and the nitrification process by the aerobic phase enables the treatment of high concentrations of nutrients without dilution.

The final effluent not conveyed through the nitrification step F is discharged after passing through the ozone tank 55 through a third treatment step G such as chromaticity removal. In general, biologically unprocessed organics are representative of lignin components of plants, and chemical decomposition or binding / precipitation is the only way to decompose these components. Chromaticity-inducing substances are also representative non-degradable organic substances, and chemical treatment is inevitable. In the third treatment step of the present invention, the hardly decomposable organic material is decomposed by the strong oxidizing power of ozone, and the color material is also decomposed.

In addition, the method of the present invention further comprises a recycling step (E) of selectively returning the sludge separated through the anaerobic / aerobic reactor combined with the membrane of the dephosphorization step (C ') to the anaerobic tank, composting excess sludge can do. The sludge discharged in the process of the present invention is returned to the anaerobic tank, or the excess sludge is recycled to the compost or the like through the centrifugal concentrated dehydrator, there is no sludge discharge at all throughout the process.

The recycling apparatus 50 usable in the recycling step of the present invention is known devices, for example, by controlling the moisture and carbon / nitrogen ratio (C / N ratio) of the solids separated from the livestock wastewater, using a microorganism to remove the release organic matter. It produces high quality compost or land improver by decomposing, removing various harmful substances and extinguishing germs. In another example, solids separated from food wastewater are aged to produce feed.

Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various modifications and variations are possible without departing from the scope of the invention. Therefore, the appended claims, the protection scope of the present invention includes such modifications or variations.

According to the method including the anaerobic / aerobic reactor and the aerobic filter combined with the separator according to the present invention, it is possible to remove suspended solids, nitrogen and phosphorus at the same time, thereby efficiently treating high concentration organic wastewater.

According to the present invention, all the sludge in the wastewater treatment process is recycled, so that there is no sludge outflow, the problem caused by the sludge treatment can be overcome.

In addition, according to the present invention, as the recycle ratio of the aerobic filter bed is increased, the methane gas content of the high rate microbial agitator is increased, thereby obtaining an advantage of using energy efficiently.

Claims (7)

In treating high concentration organic wastewater, Pretreatment to filter out large contaminants in the wastewater; A first biological treatment step of treating the pretreated wastewater with a high rate microbial reaction stirrer to decompose high concentrations of organic matter and nutrients contained in the wastewater; A dephosphorization step of decomposing phosphorus in the wastewater by treating the wastewater treated in the previous step through an anaerobic / aerobic reactor combined with a separator; Nitrifying the wastewater that has undergone the dephosphorization step through an aerobic filter and then returning to the first biological treatment step; Wastewater and high concentration organic wastewater treatment method comprising a third treatment step of ozonating the denitrified wastewater. The method of claim 1, wherein the pretreatment step includes passing a contaminant treatment device for filtering large contaminants, a collector for collecting and pumping wastewater filtered from the contaminant treatment device, and a centrifuge for rotating the waste water and centrifuging the small contaminants. Wastewater and high concentration organic wastewater treatment method characterized in that. The method of claim 1, wherein the first biological treatment step is a high-rate microbial reaction stirrer for reacting the wastewater from which the contaminants have been filtered in the pretreatment step with oxygen and purifying the wastewater by using microorganisms inside, and effluent mixed with microorganisms and treated water. Wastewater and high concentration organic wastewater treatment method characterized in that the step of processing through a centrifugal concentrated dehydrator separating the sludge. The method of claim 1, wherein the dephosphorization step comprises an anaerobic tank for releasing phosphorus using dephosphorus microorganisms; Wastewater and high concentration organic wastewater treatment method characterized in that the wastewater is treated through an aerobic reaction tank combined with a membrane for absorbing phosphorus using the dephosphorus microorganism under aerobic conditions. The method of claim 1, wherein the nitrifying step comprises nitrifying the treated water through an aerobic filter (BAF) filled with contact media. The method of claim 5, wherein the nitrification step is to increase or decrease the recycle ratio of the treated water discharged from the aerobic filter to adjust the ratio of the inflow and recycle flow rate of 1: 1 to 1: 3, methane generation rate of the high rate microbial stirrer Wastewater and high concentration organic wastewater treatment method characterized in that the step of 60% to 90%. 7. The waste water according to any one of claims 1 to 6, wherein the method further comprises a recycling step for returning the sludge separated from the aeration tank of the nitrification step to an anaerobic tank and composting excess sludge. High concentration organic wastewater treatment method.

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