KR100437863B1 - A waste water treatment apparatus comprising a trickling filter tank filled with an absorbing filter medium and a denitrification tank filled with a mixture of sulfur and limestone or apatate and a waste water treatment method using the same - Google Patents

Abstract

PURPOSE: Provided is a wastewater treatment apparatus comprising a trickling filter tank filled with absorbent filter medium and a denitrification tank filled with mixture of sulfur and limestone or apatite, which exhibits high operation efficiency regardless of organic load change of wastewater and inflow fluctuation. CONSTITUTION: The apparatus comprises a coagulation tank into which coagulant is fed to precipitate suspended solids and insoluble phosphorus contained in wastewater; a trickling filter tank which is equipped with an air spray nozzle(32) at upper side thereof and an air fan(35) to circulate air inside the trickling filter tank; and a denitrification tank where sulfur and one material selected from limestone and apatite are packed in a volume ratio of 3:1 to 1:1. Also, an adsorbent filter medium(33) having specific surface area of 220 to 280 m¬2/m¬3 is filled in the trickling filter tank in a height of 0.8 to 2.5 m.

Description

Wastewater treatment apparatus comprising a trickling filter tank filled with an absorbing filter medium and a sewage treatment tank filled with absorbent media and a denitrification tank mixed with sulfur and limestone or apatite denitrification tank filled with a mixture of sulfur and limestone or apatate and a waste water treatment method using the same}

The present invention relates to a sewage treatment apparatus and a sewage treatment method using the same, and more particularly, a flocculation sedimentation tank including an inorganic coagulant for forming suspended substances and insoluble phosphorus precipitates in sewage, a spraying filter tank filled with absorbent media and sulfur. And a sewage treatment apparatus including a denitrification tank mixed with limestone or apatite and a sewage treatment method using the same.

As a countermeasure against the rapidly polluted water environment due to the development of industry and the improvement of living standards, the water quality standards are being gradually strengthened. As a part of this trend, the removal of nutrients, especially nitrogen and phosphorus, as well as organic matter is very important. It is important.

Generally, sewage treatment methods for simultaneously removing nitrogen and phosphorus are classified into biological treatment methods for oxidizing biodegradable organic substances and physicochemical treatment methods using chemicals or other physical methods. Representative biological treatment method is activated sludge method, and activated sludge method grows as microorganisms ingest and decompose organic matter in sewage and nitrify as sewage is injected into aeration tank. Part of the precipitate precipitated in the terminal sedimentation tank is returned to the aerobic tank in the form of activated sludge, and some of the waste sludge is discarded so that the microorganisms in the aerobic tank are maintained at an appropriate level to decompose organic matter in the sewage.

In addition, Bardenpho, A / O (Anaerobic + Oxic), A ² / O (Anaerobic + Anoxic + Oxic), UCT (University of Cape Town) Methods, and advanced biological treatment methods such as the VIP (Virginia Initiative Plant) method have been proposed.

However, there are many problems in applying these techniques to our situation. In other words, in most cases, due to the lack of maintenance of sewage pipes, the actual inflow load is much lower than the design load. Therefore, it is difficult to maximize the removal efficiency of nitrogen and phosphorus by applying the above technologies that are sensitive to the influent organic load. There is this. In addition, matters such as treatment method by microbial unit operation, complex internal transfer method, pH maintenance in denitrification reaction, and power consumption of air injection device to meet proper aerobic conditions require expert maintenance. There is a problem of increasing operating costs.

Therefore, the present invention does not require the microbial unit operation, internal transport, separate pH maintenance and air injection device, so that it is easy to manage, and the sewage treatment apparatus and the apparatus that can purify sewage at low operating costs To provide a sewage treatment method using.

1 is a schematic process diagram of a sewage treatment apparatus according to the prior art,

2 is a schematic process diagram of a sewage treatment apparatus according to the present invention,

3 is a view schematically showing the water spraying tank of the sewage treatment apparatus according to the present invention,

4 is a view schematically showing a denitrification tank of the sewage treatment apparatus according to the present invention.

5 is a graph showing the change of BOD, COD and SS concentration change for each reaction tank of the sewage treatment apparatus according to the present invention.

6 is a graph showing a change in concentration of nitrogen-based material for each reaction tank of the sewage treatment apparatus according to the present invention.

7 is a graph illustrating a change in concentration of phosphorus-based material for each reaction tank of the sewage treatment apparatus according to the present invention.

<Short description of drawing symbols>

31: inlet pipe 32: spray nozzle

33: Absorbent media 34: Media support

35: air fan 36: exhaust piping

40: inlet pipe 41, 41 ': electric valve

42: level switch 43: air inlet pipe

44: air injector 45: sulfur and limestone or apatite

46: gravel 47: treated water reverse injection pump

48: treated water reverse injection pipe 49: discharge pipe

The present invention provides a coagulation sedimentation tank comprising a suspended solids in the sewage and an inorganic coagulant for forming insoluble phosphorus precipitates; Sprinklers filled with absorbent media; And it provides a sewage treatment apparatus comprising a denitrification tank mixed with sulfur and limestone or apatite.

In addition, the present invention comprises the steps of forming a suspended solids and insoluble phosphorus precipitate in sewage in the flocculation settling tank containing an inorganic coagulant; Performing organic decomposition and nitrification in a water spraying tank filled with absorbent media; And it provides a sewage treatment method comprising the step of performing a denitrification reaction in a denitrification tank mixed with sulfur and limestone or apatite.

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

1 is a process diagram of a sewage treatment apparatus according to the prior art. Referring to Figure 1, the sewage treatment apparatus according to the prior art is provided with an anaerobic tank, an oxygen-free tank, aeration tank and settling tank, each reaction tank required a complicated microbial unit operation, complex internal transport and pH maintenance.

Figure 2 is a process diagram of the sewage treatment apparatus according to the present invention, which includes an inorganic coagulant, which is filled with a flocculation sedimentation tank and an absorbent filter medium to form suspended matter and insoluble phosphorus precipitate in sewage, decomposing organic matter in sewage and nitrifying A desalination tank for carrying out the reaction, and a denitrification tank in which sulfur and limestone or apatite are mixed and filled to remove nitrogen from the sewage by autotrophic denitrification.

Existing A ² O process removes suspended substances and insoluble phosphorus through complex steps of accumulating phosphorus in anaerobic tank, inducing phosphorus release in aerobic tank, and discarding sludge in sedimentation tank. Requires professional maintenance However, the sewage treatment apparatus according to the present invention is provided with a coagulation sedimentation tank for sedimentation and removal of suspended substances and insoluble phosphorus by simply administering an inorganic coagulant, thereby reducing the site of the facility and facilitating maintenance. Better treatment efficiency can be achieved than the A ² O method.

Inorganic coagulant filled in the flocculation tank according to the present invention, as the inorganic coagulant commonly used in the art, for example, an inorganic coagulant such as aluminum sulfate, polyaluminum chloride and polyaluminum silicate may be used.

3 shows a sprinkling water tank of the sewage treatment apparatus according to the present invention. In the water tank, the decomposition and nitrification of the organic material using the non-immersion water spray biofilm or the absorbent medium 33 is performed. The sewage flows into the upper inlet pipe 31 of the spraying filter tank and comes into contact with the absorbent filter bed layer 33 which is a biofilm, and then is discharged into the lower discharge pipe 36.

Absorbent media 33 has a cube or spherical shape, it may be made of a filter foam of urethane sponge.

In addition, the specific surface area of the absorbent medium is preferably from 220 to 280 m ² / m ³ in order to enable the attachment of a large amount of microorganisms, and the water spraying tank is preferably filled with a height of about 0.8 m to 2.5 m. Do. Due to this large specific surface area, it is possible to attach a large amount of microorganisms to the absorbent media, and because aerobic microorganisms and anaerobic microorganisms can coexist to realize a random condition in which a variety of microorganisms exist, they are not sensitive to load fluctuations of sewage. In the lower part, since the substrate for the microorganism is almost depleted, the sludge generation hardly occurs due to the self-decomposition of the endogenous respiration step in which the microorganism is used as the substrate of another microorganism.

In addition, the spray nozzle 32 of the upper part of the filter sprays air in the air dissolved in the spray liquid for supplying oxygen necessary for the growth of microorganisms in the biofilm, and the air fan 35 circulates the air internally, so that separate air injection There is no need to install a device or blower, which saves power costs.

The water spraying tank may be an integral type of vertical circular structure made of polyethylene, and may further include a square or rectangular reinforced concrete structure. Reinforced concrete structures are usually buried underground, and are not significantly limited by the shape of the site than the vertical circular structure made of polyethylene, and are structurally more stable. In addition, in a large-capacity facility, installation is possible at a lower cost than a vertical circular structure made of polyethylene. The lower part of the reinforced concrete structure has a grating made of FRP material with a thickness of 25 mm to 40 mm capable of supporting the absorbent media, and spray nozzles are disposed so that the sewage is evenly sprayed on top of the absorbent media filled with 0.8 m to 2.5 m height. do.

4 shows a denitrification tank of the sewage treatment apparatus according to the present invention. The denitrification tank oxidizes the nitrifying solution transferred from the water spraying tank without any additional carbon source or alkali, and oxidizes the electron acceptor NO ₃ ^-- N or NO ₂ ^-- N as the reduced sulfur compound is oxidized to the final product SO ₄ ^2- . It is a reactor for removing nitrogen by denitrification.

The sewage is introduced into the denitrification tank from the upper inlet pipe 40 of the denitrification tank and is contacted with the sulfur-limestone layer or the apatite bed and discharged to the lower discharge pipe 49 of the denitrification tank. Sulfur and limestone or apatite 45 are mixed and filled in a volume ratio of 1: 1 to 3: 1 to prevent degradation. If the volume of limestone or apatite mixed is less than the above range, the pH decrease due to independent denitrification cannot be prevented. If the volume of the limestone or apatite exceeds the above range, the contact time and area of the sewage and sulfur are different. This reduces the processing efficiency. In the lower part of the denitrification tank, gravel 46 is provided to prevent the outflow of sulfur and limestone or apatite.

In addition, the denitrification tank is provided with electric valves 41 and 41 'and a level switch 42 for automatically controlling the inflow and outflow of sewage, and for preventing the clogging of voids formed by sulfur and limestone or apatite mixture. An air injector or blower 44 and a treated water reverse injection pump 47 are provided. The air inlet pipe 43 for introducing the air introduced from the air injector or the blower 44 into the denitrification tank has two holes having a diameter of 2 to 3 mm in the 45 degree direction and the bottom of the denitrification tank at regular intervals. In the treated water reverse injection pipe 48 for introducing the treated water introduced from the reverse injection pump 47 into the denitrification tank, holes of 3 to 4 mm in the 90 degree upward direction are drilled at regular intervals.

In addition, the present invention provides a sewage treatment method using the sewage treatment apparatus, which comprises the steps of forming a suspended material and insoluble phosphorus precipitate in the sewage in the flocculation sedimentation tank containing an inorganic coagulant; Performing organic decomposition and nitrification in a water spraying tank filled with absorbent media; And performing a denitrification reaction in the denitrification tank mixed with sulfur and limestone or apatite.

Hereinafter, the present invention will be described in more detail with reference to the following Examples, which are illustrative only to aid in understanding the present invention, and do not limit the true scope of the present invention.

<Example>

Example 1 Changes in Concentrations of Organics and Suspended Materials by Processing Process

Table 1 shows the change in the concentration of organic matter (BOD, COD) and suspended solids (SS) according to the treatment process, and FIG. 5 shows a graph showing the change in BOD, COD and SS concentration for each reactor.

Influent Flow adjustment tank Coagulation sedimentation tank Watering Denitrification tank BOD 145.6 125.1 66.5 5.5 3.8 COD 105.3 98.3 60.5 15.5 13.4 SS 140.0 108.8 32.5 3.3 2.5

Unit: mg / L

As can be seen from Table 1 and FIG. 5, the concentration of suspended solids was rapidly decreased from 108.8 mg / L to 3.3 mg / L after flocculation settling and water spraying, and the concentration of organic matter was 125.1 mg / L for BOD. At 5.5 mg / L, COD was rapidly reduced from 98.3 mg / L to 15.5 mg / L. From this, it can be seen that coagulation sedimentation tank and sprinkling tank are the main treatment processes for organic matter and suspended solids.

Example 2 Change in Concentration of Nitrogen-Based Substances by Treatment Process

Table 2 shows the concentration change of nitrogen-based materials (TN, TKN, NH ₃ ⁺ -N, NO ₂ ^-- N and NO ₃ ^-- N) for each treatment process, Figure 6 shows the nitrogen-based materials of each reaction tank The trend of concentration change is shown graphically.

Influent Flow adjustment tank Coagulation sedimentation tank Watering Denitrification tank T-N 40.4 39.4 36.4 23.4 10.1 TKN 40.2 28.2 24.3 2.3 1.5 NH ₃ ⁺ -N 36.7 27.6 23.9 1.2 0.6 NO ₂ ^-- N - 0.4 1.1 0.3 0.1 NO ₃ ^-- N 0.2 11.2 12.1 21.1 8.6

Unit: mg / L

As can be seen from Table 2 and Figure 6, except for the NO ₃ ^-- N concentration of TN, TKN, NH ₃ ⁺ -N and NO ₂ ^-- N step by step through the settling tank, spraying tank and denitrification tank NO ₃ ^-- N was increased to 21.1 mg / L until the water treatment phase, and decreased to 8.6 mg / L in the denitrification tank. The organic nitrogen is removed through each reaction tank, nitrification is carried out in the water-sorption tank, and converted to NO ₃ ^-- N. In the denitrification tank, the reduced sulfur compound is oxidized to the final product SO ₄ ^2- , and the electron acceptor. the NO ₃ ^- -N and NO ₂ ^- in the air by emitting a -N to N ₂ gas is determined to be due to the removal of nitrogen-based materials. The volume load of the denitrification tank was found to be 0.21 kg NO ₃ ^-- N / m ³ · day.

Example 3 Concentration Change of Phosphorous Substances by Process

Table 3 shows the change in concentration of phosphorus-based materials (TP and PO ₄ -P) for each treatment process, and FIG. 7 shows a graph of the concentration change of phosphorus-based materials for each reactor.

Influent Flow adjustment tank Sedimentation tank Watering Denitrification tank T-P 4.2 4.1 1.1 0.9 0.8 PO ₄ -P 3.8 3.8 0.8 0.7 0.7

Unit: mg / L

As can be seen from Table 2 and FIG. 7, the TP concentration of the influent was 4.2 mg / L, showing a removal rate of 73.8% at 1.1 mg / L in the sedimentation tank. In addition, the inflow concentration of PO ₄ -P was 3.8 mg / L, and most of the phosphorus in the sewage was insoluble. As shown in FIG. 7, the phosphorus-based material was mostly removed by chemical reaction and precipitation, and the flocculating precipitant used for the treatment of the phosphorus-based material was added in an amount of 4.5 kg / day as polyaluminum chloride.

The sewage treatment apparatus and the sewage treatment method using the same according to the present invention can treat sewage with stable and high efficiency regardless of fluctuations in the sewage inflow load, and the treatment process is simple to minimize the installation area. In addition, by purifying the sewage by an independent treatment process, the internal conveyance and consequently the piping configuration and the driving part can be reduced, so that high efficiency sewage treatment with simple maintenance and low operating cost is possible.

Claims (12)

A flocculation sedimentation tank comprising a suspended solid in sewage and an inorganic coagulant for forming insoluble phosphorus precipitates; A cubical or spherical urethane sponge filter foam filled with absorbent media having a specific surface area of 220 to 280 m ² / m ³ to a height of 0.8 to 2.5 m, and top spray nozzle and internal air for the injection of oxygen air A spraying tank comprising an air fan for circulation of the water; And A sewage treatment apparatus comprising a denitrification tank filled with sulfur and limestone or apatite in a volume ratio of 3: 1 to 1: 1. The sewage treatment apparatus according to claim 1, wherein the inorganic coagulant is selected from the group consisting of aluminum sulfate, polyaluminum chloride, and polyaluminum silicate. delete delete delete delete The sewage treatment apparatus according to claim 1, wherein the water spraying tank is an integral type of vertical circular structure made of polyethylene. The sewage treatment apparatus of claim 1, wherein the water spraying tank further comprises a square or rectangular reinforced concrete structure. delete The sewage treatment apparatus according to claim 1, wherein the denitrification tank includes an electric valve and a level switch for automatically controlling inflow and outflow of sewage. The sewage treatment apparatus according to claim 1, wherein the denitrification tank is provided with an air injection device and a treatment water reverse injection device for preventing the clogging of voids formed by sulfur and limestone or apatite mixture. Forming a suspended material and insoluble phosphorus precipitate in sewage in an flocculation settling tank comprising an inorganic coagulant; Performing organic decomposition and nitrification in a spraying filter tank filled with absorbent media; And A sewage treatment method comprising the step of performing a denitrification reaction in a denitrification tank mixed with sulfur and limestone or apatite.