KR20140067307A - Advanced treatment method for purifying wastewater - Google Patents

Abstract

The present invention relates to an advanced treatment method for purifying wastewater which comprises a) a step of denitrification by raw water flowing into a first anaerobic tank including a first fluidized carrier; b) a step of nitrogen oxidation and decomposing organic materials by the raw water which have passed through step a), flowing into a first oxygen tank including a second fluidized carrier; and c) a step for removing all phosphorus by injecting a coagulant after the raw water which have passed through step b), flows into a second oxygen tank in which a separation film is immersed, or by mixing the raw water with the coagulant and making the same to flow into a rapid precipitation tank.

Description

{Advanced treatment method for purifying wastewater}

The present invention relates to a method for advanced wastewater treatment, and more particularly, to a wastewater treatment method capable of removing a total wastewater without any additional facilities.

Water is an essential material that maintains the life of all living things on the earth. It flows into the snow or rain on the surface of the water through the circulation of water. In Korea, rainfall is considered to be a finite resource due to local or seasonal rainfall.

The dirty water used by human beings was purified by self-purification function which is the principle of nature and returned to the natural world to play the role of maintaining the ecosystem. After the Industrial Revolution, water pollution became serious due to urbanization and industrial development due to population concentration Therefore, there is a growing need for active development of ways to economically recycle wastewater.

An important point in the recycling of wastewater is to treat the contents of nitrogen, phosphorus, and organic substances in recycled wastewater, turbidity and pH of water to the required level, and remove the pathogenic microorganisms and treat them to be environmentally stable.

The introduction of nitrogen or phosphorus from agricultural fertilizers, manure or livestock manure or synthetic detergent into the water system causes eutrophication, coastal red tide, ammonia fish toxin, dissolved oxygen in the water, and ammonia Increases the demand for chlorine and, if nitrate nitrogen is present at a high concentration in the drinking water, causes diseases such as cyanosis and affects health.

In addition, excessive growth of algae due to the inflow of water sources such as nitrogen and phosphorus may cause discomfort in taste and odor of tap water, clogging of sand filter paper as a water purification process, and toxic substances It also creates a hindrance to human health.

As described above, the influx of nitrogen and phosphorus into the water causes problems such as economic loss due to an increase in the cost of water purification, difficulty in securing safe and clean water resources in public health, and thus, blocking the influx of nutrients into the water The most fundamental solution is the removal of organic matter from wastewater and livestock wastewater, as well as the treatment of nitrogen and phosphorus.

Membrane Bio-Reactor (MBR) has been developed for the treatment of nitrogen and phosphorus, combining an advanced treatment process with a biological process for treating pathogenic microorganisms and suspended substances.

The MBR-based wastewater treatment system has a small installation area and is easy to operate automatically when compared with the conventional activated sludge process, which is a conventional wastewater treatment method. Moreover, it does not include a settling tank and can solve problems such as sludge bulking And has been widely used in small-scale sewage treatment facilities. Particularly, because the quality of treated water can be adjusted according to the selection of the membrane, it is used in small water storage facilities in line with the policy consideration for the recent water reuse.

  The MBR-based wastewater treatment system is known to be disadvantageous in terms of removal of phosphorus because the amount of surplus sludge generated is much smaller than that of the conventional method and this is accepted as an advantage of the MBR system. Thus, there has been a demand for an MBR system for simultaneous removal of nitrogen which is complementary to the drawbacks in the phosphorus removal aspect.

Accordingly, Korean Patent Laid-Open No. 10-2010-0088283 discloses a method for disposing and treating a wastewater using a separation membrane. The first anoxic tank, the oxic tank, the second anoxic tank, the membrane separation unit, the membrane module, The present invention relates to an apparatus and a method for processing wastewater containing a management section. However, the process is complicated, and there is a disadvantage that the effect of removing vaginal, phosphorous and organic matters is not sufficient.

Korean Patent Publication No. 10-2010-0088283 (Aug., 2010)

The present invention relates to a method of treating a wastewater with high concentration of total phosphorus to a low concentration without additional facilities. In the first oxygen tank, one or more microorganisms selected from nitrifying microorganisms and carbon oxidizing microorganisms are attached A biological process capable of performing nitrogen oxidation and organic decomposition in the raw water is performed using the second fluidized bed support having the second fluidized bed support and the separation membrane is immersed in the second oxygenation tank and a physicochemical process The present invention provides a method for treating a wastewater having biological processes and physicochemical processes separated therefrom,

In addition, the present invention may include a physico-chemical process that is composed of a high-speed settling tank instead of the second oxygen tank and can perform solid-liquid separation. Before the raw water decomposed with nitrogen and organic matter is introduced into the fast settling tank, The present invention is directed to a method for treating wastewater, which comprises the steps of: preparing a chemical admixture or an in-line mixer containing nitrogen oxides and organic raw materials;

The present invention solves the problem of inhibition of nitrification due to the coagulant injection by using a fluid carrier as described above and separates the biological process from the physicochemical process and reduces the amount of coagulant required according to the low MLSS concentration and the minimum co- It is an object of the present invention to provide a method of treating wastewater as possible.

Recently, as TP (total phosphorus) standard has been greatly strengthened in order to prevent water eutrophication, the post-precipitation method that combines aggregate facilities based on flocculation-filtration in the wastewater treatment process at the end of existing wastewater facilities (Co-Precipitation) process in which a coagulant is directly injected into a biological reactor and removed together with microbial sludge has been applied. Particularly, in MBR process, which has recently been spotlighted, there is no particulate matter that acts as a coagulation nuclei in the treated water due to complete solid-liquid separation. Therefore, there is a limit in application of the post-treatment process. In the conventional MBR process, When the coagulant is injected into the biological reactor, the concentration of the coagulant of 3 ~ 5 mol Al / mol P, which is much higher than theoretically required 1.1 mol Al / mol P due to the high concentration MLSS of 6,000 ~ 10,000 mg / In addition, it has been reported that not only a large amount of sludge is generated but also coagulant is inhibited by nitrification as it is directly applied to the biological process.

In order to solve the above problems, the present inventors have found that the use of a fluid carrier enables the use of a fixed-bed microorganism process, a biological process and a physicochemical process, which are capable of removing the concentration of total phosphorus We developed advanced processing method.

The present invention

a) a step of introducing raw water into a first anoxic tank containing a first fluid phase carrier and performing denitrification;

b) introducing the raw water having been subjected to the step a) into the first oxygen tank containing the second fluid phase carrier to decompose nitrogen and organic matter;

c) The coagulant is injected into the second oxygen tank in which the separation membrane is immersed, after the raw water passed through the step b) is introduced, or the raw water after the step b) is mixed with the flocculant and then flows into the rapid precipitation tank, The method comprising the steps of:

The present invention also relates to a process for the preparation of a crude drug or an in-line mixer, wherein the raw water having been subjected to the step b) is introduced into a chemical admixture or an inline mixer including the coagulant injecting facility, before the raw water having been subjected to the step b) is mixed with the coagulant, And then flows into the rapid sedimentation tank.

The present invention also relates to a method for treating wastewater, characterized in that the first acid catalyst and the second oxygen tank are separated from each other by partition walls formed in one oxygen tank.

The present invention further relates to a method for treating wastewater treatment, wherein the first anoxic tank further comprises a first settling tank in the method for treating wastewater.

The present invention also relates to a method for treating wastewater characterized in that the MLSS concentration of the first fluidized bed support in step a) and the fluidized bed support in step b) is 500 to 1,000 mg / L.

Further, the present invention relates to a method for treating wastewater, characterized in that the first fluidized bed support has a denitrifying microorganism attached to the support.

The present invention also relates to a method for treating wastewater, characterized in that the second fluid phase carrier is attached to one or more microorganisms selected from nitrifying microorganisms and carbon oxidizing microorganisms.

The present invention also relates to a method for treating wastewater, characterized in that the carrier is a processed material such as plastic, ceramic, foamed rubber, porous polymer foaming agent and the like.

The present invention also relates to a method for treating wastewater, characterized in that the first anoxic tank in step a) comprises a carrier liquid transported from the first oxygen tank.

The present invention also relates to a method for treating wastewater characterized in that the flocculant in step c) is one or two selected from aluminum sulfate, aluminum polychloride, sodium aluminate, ferric chloride, ferrous sulfate and ferric chloride.

Further, the present invention is characterized in that the coagulant injection rate is 1 to 5 Al / mol P. The present invention relates to a wastewater treatment method capable of removing total phosphorus without additional facilities.

The present invention also relates to a method for treating wastewater, characterized in that the separation membrane is a microfiltration membrane and is a hollow fiber or flat plate filter having a nominal pore size of 0.01 to 0.04 μm.

The present invention also relates to a method for treating wastewater, wherein the total concentration of treated wastewater treated by the wastewater treatment method is 0.2 ppm or less.

According to the present invention, it is possible to separate the physico-chemical process for filtering the treated water through the biological process, the coagulant injection and the separation membrane using the fluid carrier, thereby solving the problem of nitrification due to the coagulant injection. In addition, by injecting coagulant into the oxygen bath immersed in the separation membrane, it is possible to solve not only the aggregation of the dissolved phosphate but also the factor of increase of the membrane pressure difference (TMP) due to the microflux of the fixed bed process, which is relatively small compared to the macro- (HRT) can be reduced compared with the submerged process, and it is possible to reduce the amount of coagulant depending on the low MLMS concentration and to minimize the coagulation sludge minimum discharge There is a possible effect.

Hereinafter, the present invention will be described in detail.

The present invention may be specifically composed of a first anoxic tank, a first oxygen tank, and a second oxygen tank, wherein a partition wall is formed in one oxygen tank to separate the space into a first oxygen tank and a second oxygen tank, The oxygen tank may further include a flocculant injecting device capable of injecting a flocculant.

In addition, the present invention may include a first anoxic tank, a first oxygen tank, and a rapid sedimentation tank. The flocculant injecting device and the rapid adhering device capable of injecting the flocculant for removing phosphorus in the pre- And may further include a mixer.

The coagulant injecting device is for adjusting the amount of coagulant injected appropriately. The on-line PO ₄ -P concentration measuring device can be installed and operated in conjunction with the coagulant injection pump. So that it can be injected.

The rapid settling tank is for separating the solidified aggregate from the treated water. The rapid settling tank may comprise a swash plate for shortening the settling time, a weir for separating treated water, and a sludge discharge facility.

The method for treating wastewater according to the present invention

a) a step of introducing raw water into a first anoxic tank containing a first fluid phase carrier and performing denitrification;

b) introducing the raw water having been subjected to the step a) into the first oxygen tank containing the second fluid phase carrier to decompose nitrogen and organic matter;

c) The coagulant is injected into the second oxygen tank in which the separation membrane is immersed, after the raw water passed through the step b) is introduced, or the raw water after the step b) is mixed with the flocculant and then flows into the rapid precipitation tank, step; . ≪ / RTI >

Before the raw water having been subjected to the step b) in the step c) is mixed with the flocculant and then introduced into the rapid precipitation tank, the raw water having been subjected to the step b) is introduced into a chemical admixture or an inline mixer But it is not limited as long as the coagulant and the raw water after the step b) can be mixed.

The first oxygen tank and the second oxygen may be separated from each other by a partition wall formed in one oxygen tank. The first oxygen tank and the second oxygen tank are separated from each other and not limited thereto.

In the present invention, since the fluidized bed carrier is constituted, and the first oxygen tank and the second oxygen tank are separated or constituted by the first oxygen tank and the high-speed settler, the space of the physicochemical process in which the biological process, Thereby improving the efficiency of the wastewater treatment process and simplifying the process configuration.

In addition, the apparatus may further include a screen or a primary settling tank for treating the contaminants contained in the raw water (wastewater) before the first anoxic tank operation, and may further increase the biological removal efficiency by adding an anaerobic tank.

It is preferable that the MLSS concentration of the first fluidized bed support in step a) and the fluidized bed support in step b) is in the range of 500 to 1,000 mg / L, and when the MLSS concentration is in the above range, The denitrification reaction, the nitrogen oxidation and the organic matter can be decomposed smoothly. In addition, since the MLSS concentration of the suspended phase can be minimized, the amount of coagulant can be reduced, and co-sludge can also be discharged to a minimum.

The denitrifying microorganism may be adhered to the first fluidized bed support, and the second fluidized bed support may be attached to one or more microorganisms selected from nitrifying microorganisms and carbon oxidizing microorganisms.

The first fluidized bed support and the second fluidized bed support used in the present invention means a form in which a microorganism is attached to a support. The support is not limited to the above, but may be a plastic, a ceramic, a foamed rubber, May be used. Preferably, a PVA gel or a PE carrier may be used. By using such a carrier, it can have a very large specific surface area, that is, 300 to 800 m ² / g, so that the ability to adhere microorganisms can be improved.

BOD and nitrogen are usually contained in raw water (raw wastewater), and nitrogen in raw water is organic nitrogen (Org-N), ammonia nitrogen (NH ₃ -N), nitrite nitrogen (NO ₂ -N) Nitrogen (NO ₃ -N), and the main forms are mostly organic nitrogen and ammonia nitrogen.

The mechanism of biological nitrogen removal using microorganisms is basically divided into denitrification (denitrification) and nitrification. In the first anoxic tank of the present invention, denitrification occurs due to the first fluid carrier.

The first anoxic tank of the present invention may include a raw liquid that flows in from the outside and a carrier liquid that is transported from the first oxygen tank. At this time, the screen may be configured such that the second fluidized carrier is not carried along with the first oxygen tank. have.

The incoming transport liquid contains nitrate nitrogen (NO ₃ -N), and the denitrification reaction proceeds using the organic matter in the raw water.

The denitrification reaction may occur only under the condition of the anoxic tank, and the nitrate nitrogen (NO ₃ -N) is reduced into the form of nitrogen (N ₂ ) gas, and the organic substance (BOD) And the denitrification reaction using the organic matter accumulated in the denitrifying microorganisms of the first fluidized bed support in the anoxic tank can finally remove nitrogen.

The first oxygen tank and the second oxygen tank of the present invention may exist in independent spaces as the partition walls are formed in one oxygen tank. In the first oxygen tank, the nitrification reaction may proceed by a biological process, A physicochemical process using a separation membrane and a coagulant may be performed.

The nitrification reaction in the first oxygen congealing step may be performed by changing the ammonium (NH4 ⁺ ) to nitric acid (NO3 ^- ) by allowing the second fluidized carrier to which one or two or more microorganisms selected from nitrifying microorganisms and carbon- In order to achieve nitrification, two steps are required.

Gritty, for example describes a two-step process, the first step is the second nitrite (NO2 ^-) ammonium (NH ₄ ⁺⁾ by using a molecular oxygen by the microorganisms affixed to the fluid ^{carrier-converted} to nitrate (NO ₃₎ . Assuming that the molecular formula of the nitrifying microorganism is C ₅ H ₇ NO ₂ , nitrification considering the assimilation of new microorganisms may include the following reaction.

[Reaction Scheme]

NH ₄ ⁺ + 1.830 ₂ + 1.98 HCO ₃ ^-

_{-> 0.021C 5 H 7 NO 2} + 1.041H 2 O + 0.98NO 3 + 1.88H 2 CO 3

The second oxygen tank may include a flocculant and a separation membrane, and the separation membrane may be a microfiltration membrane. The microfiltration membrane may be, for example, a hollow fiber or flat plate filter having a nominal pore size of 0.01 to 0.04 μm, but is not limited thereto.

The flocculant may be one or two or more selected from aluminum sulfate, polyaluminum chloride, sodium aluminate, ferric chloride, ferrous sulfate and ferric chloride. Preferably, the flocculant is aluminum, which is inexpensive and non-toxic It is preferable because it is easy to handle and does not cause corrosion and irritation, and it is preferable because it can maintain a pH range of 5.5 to 8.5 which can precipitate fine sediment by adsorbing suspended particulate matter and smooth flocculation. However, It is not.

In the present invention, the coagulant may be injected into the second oxygen tank and the rapid precipitation tank in which the separation membrane is immersed. In this case, a rapid mixing apparatus may be added to maximize the effect of the coagulant in the second oxygen tank.

In order to adjust the amount of coagulant injected, an on-line PO ₄ -P concentration measuring device can be installed and operated in conjunction with the coagulant injection pump. That is, the coagulant injection amount is determined through real-time phosphorus concentration analysis and can be automatically injected. The amount of the flocculant to be injected is preferably 1 to 5 Al / mol P, and if the flocculant is injected in the above range, the amount of the flocculant can be efficiently used and it is preferable to treat the total phosphorus to 0.2 ppm or less.

In addition, when the flocculant is injected in the above range, not only the removal of phosphorous but also the micro flocs such as floating microorganisms in the second oxygen tank and the rapid sedimentation tank, microorganisms separated from the carrier, or floating matters in the inflow water can be agglomerated. Accordingly, it is possible to effectively improve the problem that the differential pressure in membrane filtration during the membrane filtration due to the micro flocs in the second oxygen tank is drastically increased.

Further, according to the present invention, the total phosphorus concentration of the treated water treated by the above-mentioned method for treating wastewater can be reduced to 0.2 ppm or less and the total phosphorus concentration of the raw water can be set to 0.2 ppm without any additional phosphorus treatment, And it is possible to provide a compact wastewater treatment method.

Further, the present invention has a low TTF (Time to Filter) value of less than 1/10 as compared with a general A20 type MBR process when raw water is treated by the above-mentioned wastewater treatment method, It can be seen that the remarkable rise can be effectively controlled, which means that stable separation membrane operation is possible.

For example, when the coagulant is injected at a rate of 1 to 5 Al / mol P using the coagulant injector in the process according to the present invention, it has a time range of 4 to 11 sec. When the coagulant is injected, the TTF is decreased by 62% compared with the case of the coagulant.

According to the method for treating wastewater according to the present invention, it is possible to solve the problem of inhibition of nitrification due to the coagulant injection by the use of the fixed bed microorganism process and to solve the problem of increasing the membrane pressure difference (TMP) due to microflux. In addition, it is possible to reduce the hydraulic retention time (HRT) compared with the submerged process, and it is possible to reduce the amount of coagulant according to the low MLMS concentration and to minimize the microbial sludge discharge. Also, according to the method for treating wastewater according to the present invention, it is possible to provide a method of treating a wastewater with a low concentration, which can be removed without additional facilities, and the process can be simplified.

FIG. 1 and FIG. 2 are views showing a wastewater treatment apparatus according to the present invention.
FIGS. 3 and 4 show the process of removing the TP through the coprecipitate in the bioreactor,
3 is a view showing a TP removal process by coprecipitation in the activated sludge system,
4 is a view showing a TP removing process (MBR process) by coprecipitation, which is a process used in Comparative Example 2 of the present invention.
FIGS. 5 and 6 show the TP removal through the after-treatment of the bioreactor treated water,
FIG. 5 is a view showing a TP removal process through the afterglow in the activated sludge system,
6 is a view showing a process of removing TP by providing a post-processing step at the end of the MBR process.
7 is a view showing a process used in Comparative Example 2 of the present invention.

The present invention may be better understood by the following examples, which are for the purpose of illustrating the present invention and are not intended to limit the scope of protection defined by the appended claims.

The water quality analysis of the treated water according to the present invention was performed according to the water pollution process test method (Ministry of Environment, Water Pollution Process Test, 2006). The analytical methods for each item are shown in the following table.

[Table] Method of water quality analysis by measurement item

[Example 1]

A pilot having a treatment capacity of 1 m ³ / d is installed in a WWTP to measure the actual inflow sewage water 10 in the first anoxic tank 20 and the first oxygen tank 30 and the second oxygen tank 40 60) was formed on the inner surface of the reaction vessel (see Fig. 1)

The nitrate nitrogen contained in the carrier liquid 110 and the raw water 10 conveyed from the first oxygen tank 30 is supplied to the first fluidized bed support 70 and denitrifying microorganism concentration MLSS, Was transferred to the first anoxic tank 20 maintained at 1,000 mg / L or less to carry out the denitrification treatment.

The nitrification reaction was carried out by moving the denitrified raw water to the first oxygen tank (30) and keeping nitrification microorganisms and keeping the MLSS below 1,000 mg / L.

Then, a separation membrane 100 having a hollow sphere with a nominal pore size of 0.03 μm was immersed in the second oxygen tank 40. Aluminum sulfate (Al ₂ (SO ₄ ) ₃ ) as a coagulant was added to the separation membrane in an amount of 2 mol / And processed using an injection device 90. [

The TTF was measured in order to measure the filtration characteristics of the separation membrane. The measured data are shown in Table 1 below. BOD, CODcr, TN of the treated water 120 and influent 10 treated according to the above- , NH ₃ -N, TP and PO ₄ -P were measured and are shown in Table 1 below.

[Example 2]

The procedure of Example 1 was repeated except that the content of coagulant was changed to 3 mol Al / mol P.

TTF was measured in order to measure the filtration characteristics of the separation membrane 100. The measured data are shown in Table 1. The BOD of the treated water 120 and the BOD of the influent 10 treated according to the above- CODcr, TN, NH ₃ -N, TP and PO ₄ -P were measured and are shown in Table 1 below.

[Example 3]

The procedure of Example 1 was repeated except that the content of coagulant was 4 mol Al / mol P.

The TTF was measured to measure the filtration characteristics of the separation membrane 100. The measured data are shown in Table 1 below and the BOD of the treated water 120 and the influent 10 treated according to the above- CODcr, TN, NH ₃ -N, TP and PO ₄ -P were measured and are shown in Table 1 below.

[Comparative Example 1]

The same procedure as in Example 1 was carried out except that no coagulant was injected and the oxygen tank was not divided into the partition walls. TTF was measured in order to measure the filtration characteristics of the separation membrane 100. The measured data are shown in Table 1 below. In addition, the BOD of the treated water and the BOD of the influent water treated according to the above- CODcr, TN, NH ₃ -N, TP and PO ₄ -P were measured and are shown in Table 1 below.

[Comparative Example 2]

Capacity 1m ³ / d scale by installing the pilot sewage treatment plant to the charging target and the actual number of inlet 10, was carried out using the conventional apparatus of the oil phase portion MBR process. <Refer to FIG. 4>

The nitrate nitrogen contained in the carrier liquid 110 and the raw water 10 conveyed from the oxygen tank is transferred to the anoxic tank 20 maintained at the concentration (MLSS) of denitrifying microorganisms at 6,000 mg / Respectively.

The nitrification reaction was performed by moving the denitrified raw water to the first oxygen tank 30 and maintaining the concentration of nitrifying microorganisms (MLSS) at 8,000 mg / L as a float.

Then, a separation membrane having a hollow sphere with a nominal pore size of 0.03 μm was immersed in the oxygen tank and treated with 3 mol Al / mol P of aluminum sulfate (Al ₂ (SO ₄ ) ₃ ) in the separation membrane 100.

TTF was measured in order to measure the filtration characteristics of the separation membrane 100. The measured data are shown in Table 1. The BOD of the treated water 120 and the BOD of the influent 10 treated according to the above- CODcr, TN, NH ₃ -N, TP and PO ₄ -P were measured and are shown in Table 1 below.

[Comparative Example 3]

A pilot plant with a treatment capacity of 1 m ³ / d was installed at Daejeon wastewater treatment plant and the actual effluent sewage was carried out using the conventional MBR process equipment. <Refer to FIG. 4>

The nitrate nitrogen contained in the carrier liquid 110 and the raw water 10 conveyed from the oxygen tank was transferred to the anoxic tank 20 containing the denitrifying microorganism concentration (MLSS) at 6,000 mg / Treatment.

The nitrification reaction was carried out by moving the denitrified raw water to an oxygen tank and containing the concentration (MLSS) of nitrifying microorganism as suspension of 8,000 mg / L.

A separation membrane 100 having a hollow fiber nominal pore size of 0.03 μm was immersed in the first oxygen tank 30 and 5 mol Al / mol of aluminum sulfate (Al ₂ (SO ₄ ) ₃ ) was added to the separation membrane 100 Injected and used.

TTF was measured in order to measure the filtration characteristics of the separation membrane 100. The measured data are shown in Table 1. The BOD of the treated water 120 and the BOD of the influent 10 treated according to the above- CODcr, TN, NH ₃ -N, TP and PO ₄ -P were measured and are shown in Table 1 below.

[ Test Example  One] Example  1 in BOD , CODcr , T-N, NH ₃ -N, T-P and &lt; RTI ID = PO ₄ -P measurement

(1) Biochemical oxygen demand ( BOD )

Biochemical oxygen demand (BOD) is one of the indicators for the concentration of organic substances in water. In general, BOD is the amount of oxygen consumed by aquatic microorganisms to stabilize decomposable organic substances at 20 ℃ for 5 days. It is widely used as an indirect measure for determining the level of the content of decomposable organic substances contained in water.

  The BOD concentration of raw water in the range of BOD 128 ~ 155 ㎎ / ℓ was high as the maximum BOD 155 ㎎ / ℓ during the investigation period. The BOD concentration of the treated water treated by the method of treating wastewater according to the present invention was found to be 0.5 to 1.1 mg / L of BOD, and a significant amount of organic pollutants were removed by the wastewater treatment method.

(2) Chemical oxygen demand ( CODcr )

The chemical oxygen demand, that is, COD, is the amount of oxygen required to oxidize organic matter in the water to a chemical oxidant. The CODcr concentration in the raw water during the irradiation period ranges from 510 to 529 mg / l of COD, which is 529 mg / l of maximum CODcr The CODcr concentration of the treated water after the treatment according to the present invention was found to be 9.0 to 15.2 mg / l of CODcr and it was found that a considerable amount of contaminants were removed by the present invention of the present invention

(3) Total nitrogen (T-N)

Nitrogen in water is present as inorganic nitrogen and organic nitrogen such as ammonia nitrogen, nitrite nitrogen and nitrate nitrogen, and the sum of these is called total nitrogen. Nitrogen is a major factor in the maintenance and determination of aquatic ecosystems and may be a limiting factor in algal growth. On the other hand, the dissolution rate of inorganic nitrogen except organic nitrogen is determined by nitrifying bacteria and denitrifying bacteria, dissolved and reduced in the form of inorganic nitrogen to participate in a series of nitrogen circulation.

The raw water (wastewater) contains a considerable amount of nitrogen compounds such as organic pollutants.

As a result of investigation on TN, the concentration of raw water ranged from 32.8 to 45.9 mg / l of TN, but the TN concentration of the treated water through the wastewater treatment method according to the present invention was 8.0 to 13.2 mg / l TN, It was confirmed that the concentration was much lowered.

(4) Ammonia nitrogen ( NH ₃ -N)

The ammonia nitrogen concentration was measured by the Nestler method. As a result of the investigation on NH ₃ -N, the concentration of the raw water was in the range of NH ₃ -N 28.2 to 32.6 mg / l. However, NH ₃ -N concentration was confirmed to be complete nitrification goes through a processing facility as NH ₃ -N 0.14 to 0.16 ㎎ / ℓ.

(5) Total Person (T-P)

In addition to the nitrogen component, phosphorus in water is a kind of nutrient salt that causes eutrophication which causes deterioration of water quality and causes overproduction of phytoplankton, which may cause deodorization and water color change.

As a result of the investigation on the TP, the concentration of TP was in the range of TP 5.6 to 8.5 ㎎ / ℓ, but the TP concentration of the treated water according to the present invention was TP 0.09-0.16 mg / And it was confirmed that it was considerably lowered.

(6) Phosphate PO ₄ -P)

Findings raw water concentration of PO ₄ -P concentration of the treated wastewater subjected to advanced treatment process according to the invention yeoteuna PO ₄ -P 2.3 to 3.5 ㎎ / ℓ range about PO ₄ -P is PO ₄ -P 0.08 to 0.12 ㎎ / ℓ, it was confirmed that the concentration of influent water was considerably lowered.

[ Test Example  2] Example  2 to 3 and Comparative Example  1 to 3 BOD , CODcr , T-N, NH ₃ -N, T-P and &lt; RTI ID = PO ₄ -P measurement

The test was carried out in the same manner as in Test Example 1 above. The contents of raw water and treated water are shown in Table 1 below.

[Table 1]

As shown in Table 1, in Example 1 in which the coagulant injection rate was 2 mol Al / mol P, it was satisfied that the TP of the most strict "Ι" region standard of the domestic effluent water was below 0.2 mg / L, In Comparative Example 1 in which the biological process and the physicochemical process were not separated and the raw water was treated without injecting the coagulant, it was confirmed that the TP did not satisfy the discharged water quality standard at 1.02-1.52 mg / L there was.

On the other hand, in the case of the conventional oil-based MBR, the concentration of TP was less than 0.2 mg / L in the case of Comparative Example 3 in which the coagulant injection rate was 5 mol / mol / mol P and satisfied the discharged water quality standard. However, It can be seen that the injection rate of the coagulant is high as compared with the case of Example 1 of the present invention having 2 mol Al / mol P. Comparing Example 2 and Comparative Example 2 in which the coagulant injection rate is 3 mol Al / mol P, the TP concentration in the treated water is 0.09-0.12 mg / L in the case of Example 2, and 0.46-0.58 mg / L in the case of Example 2 When the same flocculant was injected, the TP treatment was more effective in the case of Example. When the coagulant injection rate was increased to 4 mol Al / mol P as in the case of Example 3, the treated TP concentration was decreased to 0.1 mg / L or less Of high-altitude treatment. Also in terms of nitrogen removal, the removal efficiencies of Examples 1 to 3 were somewhat improved as compared with Comparative Example 1 in which no coagulant was injected. Thus, it was confirmed that nitrification inhibition and the like due to coagulant injection were not affected.

In the case of Comparative Example 1 in which the coagulant was not injected, it took about 18 seconds to filter 50% of the 20 mL sludge in the TTF measurement in which the filtration rate of the separation membrane was indirectly measured in the present invention. However, 1 to 3, it was found that the coagulant injection was effective in improving not only the removal of TP but also the filtration of the membrane. On the other hand, TTF in the submerged MBR process was at least 41 seconds despite the coagulant injection, which is disadvantageous in terms of membrane operation compared with the present invention.

10: raw water (incoming sewage) 20: first anoxic tank
30: first oxygen tank 40: second oxygen tank
50: Screen 60:
70: first fluidized bed carrier 80: second fluidized bed carrier
90: coagulant injection device 100: microfiltration membrane
110: Return liquid 120: Treated water
130: secondary settling tank 140: tertiary facility (total processing facility)

Claims (12)

a) a step of introducing raw water into a first anoxic tank containing a first fluid phase carrier and performing denitrification;
b) introducing the raw water having been subjected to the step a) into the first oxygen tank containing the second fluid phase carrier to decompose nitrogen and organic matter;
c) The coagulant is injected into the second oxygen tank in which the separation membrane is immersed, after the raw water passed through the step b) has been introduced, or the raw water after the step b) has been mixed with the flocculant and then flowed into the rapid precipitation tank, The method comprising the steps of: The method according to claim 1,
Before the raw water having been subjected to the step b) in the step c) is mixed with the flocculant and then introduced into the rapid precipitation tank, the raw water having been subjected to the step b) is introduced into a chemical admixture or an inline mixer And then introduced into the rapid sedimentation tank. The method according to claim 1,
Wherein the first oxygen tank and the second oxygen are separated from each other by partition walls formed in one oxygen tank. The method according to claim 1,
Wherein the MLSS concentration of the first fluidized bed carrier in step a) and the fluidized bed carrier in step b) is 500 to 1,000 mg / L. The method according to claim 1,
Wherein the first fluidized-bed carrier has a denitrifying microorganism adhered to the carrier. The method according to claim 1,
Wherein the second fluid phase carrier is attached to one or more microorganisms selected from nitrifying microorganisms and carbon oxidizing microorganisms. The method according to claim 5 or 6,
Wherein the carrier is a processed material such as plastic, ceramic, foamed rubber, porous polymer foaming agent, and the like. The method according to claim 1,
Wherein the first anoxic tank in step a) includes a carrier liquid carried from the first oxygen tank. The method according to claim 1,
Wherein the flocculant in step c) is one or two selected from aluminum sulfate, polyaluminum chloride, sodium aluminate, ferric chloride, ferrous sulfate and ferric chloride. The method according to claim 1,
Wherein the coagulant injection rate is 1 to 5 Al / mol P. The method of claim 1, wherein the coagulant injection rate is 1 to 5 Al / mol P. The method according to claim 1,
Wherein the separation membrane is a microfiltration membrane and is a hollow or flat plate filter having a nominal pore size of 0.01 to 0.04 m. The method according to claim 1,
Wherein the total phosphorus concentration of the treated water treated by the method for treating wastewater is not more than 0.2 ppm.

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