KR20060118291A - Effluent treatment equipment - Google Patents

Abstract

An equipment for wastewater treatment capable of treating industrial wastewater containing high concentrated nitrogen, phosphorous and fluorine generated from the semiconductor fabrication process more efficiently and economically is provided. An equipment for wastewater treatment comprises: an inflow part(100) for supplying wastewater to be treated, a magnesium(Mg)-based compound, a phosphate(PO4)-based compound, and an alkaline agent; a struvite crystallization reactor(104) connected to the inflow part to perform struvite crystallization reaction of the wastewater to be treated; a first settling tank(106) for performing solid-liquid separation of the wastewater to be treated that is crystallized in the struvite crystallization reactor to obtain a first solidified material and a first dissolved material; a calcium supply/reaction tank(110) for supplying calcium into the first dissolved material of the wastewater to be treated that is flown in from the first settling tank; a second settling tank(112) for performing solid-liquid separation of the first dissolved material of the wastewater to be treated that is flown in from the calcium supply/reaction tank to obtain a second solidified material and a second dissolved material; and an outflow part(116) connected to the second setting tank to discharge the second dissolved material.

Description

Wastewater Treatment Unit {EFFLUENT TREATMENT EQUIPMENT}

1 is a view briefly showing the configuration of a wastewater treatment apparatus according to an embodiment of the present invention,

FIG. 2 is a graph showing wastewater treatment efficiency in a struvite crystallization reactor in the wastewater treatment apparatus of FIG. 1.

Brief description of the symbols in the drawing

100: inlet 102: flow rate adjustment tank

104: struvite crystallization reactor 106: first precipitation tank

108: first return line 110: calcium supply / reactor

112: second settling tank 114: second conveying line

116: outlet

The present invention is a wastewater treatment apparatus using struvite precipitation to continuously process the industrial wastewater containing high concentrations of nitrogen, phosphorus and fluorine crystals in the form of struvite (MgNH ₄ PO ₄ · 6H ₂ O) It is about.

In general, many industrial fields, such as semiconductor manufacturing processes, generate large amounts of industrial wastewater containing nitrogen and phosphorus components at high concentrations. In particular, in the manufacturing process of semiconductor devices, by using a large amount of various fluorine-based compounds such as hydrofluoric acid (HF) -based etching solution, industrial wastewater containing a high concentration of fluorine components together with nitrogen and phosphorus components is generated. In recent years, as the environmental concern has increased greatly, there is a continuous demand for treatment methods that can efficiently and economically treat such industrial wastewater, and conventional treatment methods for such industrial wastewater are largely physical and chemical methods. And biological methods.

First, conventional physical and chemical methods for treating the industrial wastewater include a method of degassing and removing nitrogen components with ammonia gas through aeration and pH adjustment, and a method of coprecipitation and removal of phosphorus components with aluminum. .

However, such a conventional physical and chemical wastewater treatment method has a problem that the treatment efficiency is low, chemical cost and the composition of a specific environment is not only difficult to operate, but also the economic efficiency is greatly reduced. In addition, since many difficulties are involved in the simultaneous removal of nitrogen and phosphorus components, the treatment of industrial wastewater becomes inefficient.

In addition, as a conventional biological method for treating the industrial wastewater, wastewater treatment processes such as bardenpho, A2 / O, A / O, UTC, VIP, and the like have been developed. It is a process of treating industrial wastewater through biological means such as microorganisms while operating in combination with aeration and non-aeration. In particular, such biological treatment processes have recently been widely used in various developed countries.

However, such biological wastewater treatment process requires a long hydraulic residence time for nitrification of wastewater, especially when it is desired to treat industrial wastewater containing high concentrations of nitrogen and phosphorus, so that a lot of sites for wastewater treatment plant construction are required. There is a problem that becomes necessary. In addition, when such a site is insufficient, there is also a problem that the treatment efficiency and economic efficiency is very low due to the extremely limited throughput of wastewater that can be treated through the biological wastewater treatment process, due to the large amount of toxic substances contained in industrial wastewater. Biological wastewater treatment processes often lead to the inability to treat industrial wastewater.

Due to these problems, the development of a new wastewater treatment technology that can more efficiently and economically treat industrial wastewater containing high concentrations of nitrogen, phosphorus and fluorine components is urgently required.

In response to such a request, a wastewater treatment apparatus using struvite precipitation and a wastewater treatment method using the same have been considered.

In particular, Korean Patent Registration No. 446984, filed by Chungbuk National University Industry-Academic Cooperation Agency, uses a struvite precipitation to continuously treat industrial wastewater containing high concentrations of nitrogen and phosphorus. Device) is disclosed.

In addition, Korean Patent Application Publication No. 04-70408, filed by Chungbuk National University, discloses a wastewater treatment apparatus for oxidizing and adsorbing industrial wastewater containing high concentrations of nitrogen, phosphorus, etc. with microorganisms, and then struvite precipitation to treat it in two stages. It is.

By the way, such a conventional wastewater treatment apparatus can only process and remove nitrogen and phosphorus components in industrial wastewater, and other components cannot be removed at all, so that semiconductor manufacturing including a high concentration of fluorine and the like with nitrogen and phosphorus components is produced. It was not suitable for treating industrial wastewater in the process.

In addition, when the struvite precipitation process is carried out in the wastewater treatment apparatus of the prior art, most of the nitrogen component in the industrial wastewater is removed but only about 70% of the phosphorus component is removed. There was a problem that a process is required.

Due to the problems of the prior art, there is a continuous demand for a wastewater treatment apparatus capable of more efficiently and economically treating industrial wastewater in a semiconductor manufacturing process including high concentrations of nitrogen, phosphorus, fluorine, and the like.

Accordingly, an object of the present invention is to provide a wastewater treatment apparatus capable of more efficiently and economically treating industrial wastewater in a semiconductor manufacturing process including high concentrations of nitrogen, phosphorus, fluorine, and the like.

In order to achieve this object, the present invention is to treat wastewater, magnesium (Mg) compound, phosphorus (P) compound And an inflow portion for supplying an alkaline agent, a struvite crystallization reactor connected to the inflow portion to generate a struvite crystallization reaction to the wastewater to be treated, and a wastewater to be treated crystallized in the struvite crystallization reactor. A first sedimentation tank for solid-liquid separation into solids and a first dissolved matter, a calcium supply / reaction tank for supplying / reacting calcium to the first dissolved matter of the treated wastewater introduced from the first sedimentation tank, and the inflow from the calcium supply / reactor And a second sedimentation tank for solid-liquid separation of the first dissolved matter of the treated wastewater to a second solid matter and a second dissolved matter, and an outlet connected to the second sedimentation tank for discharging the second dissolved matter. to provide.

The wastewater treatment apparatus of the present invention having such a structure is a semiconductor manufacturing process including a high concentration of nitrogen, phosphorus, and fluorine components by using precipitation through the reaction of calcium and fluorine, together with precipitation through the struvite crystallization reaction. It is possible to efficiently and economically treat heavy industrial wastewater.

On the other hand, the wastewater treatment apparatus of the present invention is connected between the first precipitation tank and the struvite crystallization reaction tank, and includes a first conveying line for returning the first solid material to the struvite crystallization reaction tank, and the second It may further include a second conveying line connected between the precipitation tank and the calcium supply / reaction tank to return the second solids to the calcium supply / reaction tank.

The wastewater treatment apparatus is capable of continuously reprocessing the first solids and the second solids by using the first and second conveying lines, which treats industrial wastewater and finally leaves residues, In other words, by minimizing the amount of sludge and securing as much water as possible from industrial wastewater, the efficiency of the wastewater treatment apparatus can be further improved.

In addition, the wastewater treatment apparatus of the present invention is provided between the inlet and the struvite crystallization tank, the flow rate adjustment tank for adjusting the supply flow rate and nitrogen loading rate of the waste water to be treated supplied to the struvite crystallization reaction tank It may further include.

In the wastewater treatment apparatus of the present invention, the wastewater to be treated, a magnesium compound, a phosphate compound And together with the alkali agent, it is more preferable to allow a predetermined amount of air to be supplied through the inlet.

Moreover, the wastewater treatment apparatus of the present invention can treat wastewater to be treated containing high concentrations of nitrogen, phosphorus, and fluorine components discharged from the semiconductor manufacturing process.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the wastewater treatment apparatus according to an embodiment of the present invention. However, this is presented as an example and thereby does not determine the scope of the present invention.

1 is a view schematically showing the configuration of a wastewater treatment apparatus according to an embodiment of the present invention, Figure 2 is a graph showing the wastewater treatment efficiency in the struvite crystallization reaction tank of the wastewater treatment apparatus of FIG.

Referring to FIG. 1, the wastewater treatment apparatus according to the present embodiment firstly produces an industrial wastewater during a semiconductor manufacturing process including high concentrations of nitrogen, phosphorus, and fluorine components, that is, a wastewater crystallization reaction with a wastewater to be treated. Magnesium (Mg) compounds and phosphorus (PO ₄ ) compounds as reactants And an inflow portion 100 for supplying an alkali agent.

As will be apparent to those skilled in the art, since struvite consists of an equivalent ratio of Mg ²⁺ : NH ₄ ⁺ : PO ₄ ^3-1 : 1: 1, any one of the three components of magnesium, nitrogen and phosphorus Lack of precipitation cannot be produced through the struvite crystallization reaction. Therefore, the inlet 100 supplies a predetermined amount of a magnesium compound and a phosphorus compound together with the wastewater to be treated so that a high concentration of nitrogen and phosphorus contained in the wastewater to be treated can cause a sturubit crystallization reaction. will be.

As the magnesium compound, all of the compounds containing magnesium may be used. Preferably, the salt water or sea water generated during the salt manufacturing process may be used, thereby further improving the economics of the wastewater treatment apparatus. In addition, the phosphorus compound may be generally supplied in the form of a phosphoric acid compound.

The magnesium compound may be supplied in an equivalent ratio in consideration of the concentration of nitrogen components in the wastewater to be treated. On the other hand, since the wastewater to be treated already contains a high concentration of phosphorus component, only a relatively small amount of the phosphorus compound may be supplied. However, the supply amount of the magnesium compound and the phosphorus compound may be obviously determined by those skilled in the art in consideration of concentrations of nitrogen and phosphorus in the wastewater to be treated.

In addition, the struvite crystallization reaction is generally known to occur under alkaline conditions of about pH 8.5-12. If the wastewater to be treated is acidic or neutral, for example, an alkaline agent such as NaOH may be used. It is supplied through the inlet 100 to adjust the pH to suit the struvite crystallization reaction occurs. The supply amount of such an alkaline agent may also be obvious to those skilled in the art in consideration of the pH of the wastewater to be treated.

The wastewater to be treated, the magnesium compound, the phosphate compound And along with the alkaline agent, a predetermined amount of air is preferably supplied through the inlet portion (100). When such air is supplied, since the pH of the wastewater to be treated may be increased by degassing carbon dioxide (CO ₂ ) in the wastewater to be treated, the amount of the alkaline agent to be supplied through the inlet 100 may be reduced.

On the other hand, the inlet 100 is in the form of one inlet pipe to supply the waste water, magnesium-based compound, phosphorus-based compound and alkali agent, etc. collectively, the wastewater to be treated and the magnesium-based compound It may be in the form of two or more inlet pipes respectively supplying a phosphorus-based compound and an alkali agent.

Further, in the wastewater treatment apparatus of the present embodiment, a flow rate adjustment tank 102 is connected to the inlet portion 100 and adjusts a supply flow rate and a nitrogen load rate of the wastewater to be treated, etc. introduced therefrom. That is, the flow rate adjustment tank 102 serves as a buffer storage tank of industrial wastewater, that is, the wastewater to be treated, which has a large flow rate change, and thus, the treatment flows into the struvite crystallization reactor 104 connected to the flow rate adjustment tank 102. The supply flow rate and nitrogen loading rate of the target wastewater are kept as constant as possible.

In addition, the wastewater treatment apparatus of the present embodiment is further provided with a struvite crystallization reactor 104 which is connected to the flow rate adjusting tank 102 to cause the struvite crystallization reaction to the wastewater to be treated which flows therefrom. .

In such a struvite crystallization reaction tank 104, nitrogen and phosphorus components in the waste water to be treated supplied from the inflow section 100 and the magnesium-based compound under alkaline conditions adjusted to approximately pH 8.5-12 by an alkaline agent. And the phosphorus compound causes a struvite crystallization reaction, whereby nitrogen and phosphorus components in the wastewater to be treated are precipitated in a struvite crystal form (MgNH ₄ PO ₄ .6H ₂ O). In particular, the inventors repeated experiments using industrial wastewater generated in the semiconductor manufacturing process as the wastewater to be treated. As shown in FIG. 2, the struvite crystallization reaction vessel 104 undergoes such a struvite crystallization reaction. As a result, it was found that about 90% or more of the nitrogen content in the wastewater to be treated is precipitated and removed, and about 78% of the phosphorus component is precipitated and removed.

In addition, in the struvite crystallization reactor 104, it was found that about 30% of the fluorine component in the wastewater to be treated is also co-precipitated and removed in the process of precipitation of nitrogen and phosphorus components by the struvite crystallization reaction. (See Figure 2).

On the other hand, in the wastewater treatment apparatus of the present embodiment, the first settling tank 106 is connected to the struvite crystallization reaction tank 104 to solid-separate the treated wastewater introduced therefrom into a first solid substance and a first dissolved substance. Is formed.

That is, in the first precipitation tank 106, at least about 90% nitrogen component, about 78% phosphorus component, and about 30% fluorine precipitated in the form of the struvite crystal in the struvite crystallization reactor 104. The component is separated and removed from the wastewater to be treated as the first solid, and the first dissolved matter of the wastewater to be treated except this is supplied to the calcium feed / reactor 110 connected to the first precipitation tank 106 for the next treatment. Is supplied.

On the other hand, the first solid is conveyed to the struvite crystallization reactor 104 by the first conveying line 108 connected between the first precipitation tank 106 and the struvite crystallization reactor 104. The first solid returned in this way is reprocessed in the struvite crystallization reactor 104, thereby maximizing the removal efficiency of nitrogen and phosphorus components from the wastewater to be treated, and ultimately after treatment of the wastewater to be treated. By minimizing the amount of sludge remaining as, it is possible to improve the efficiency of the wastewater treatment apparatus of this embodiment.

In the wastewater treatment apparatus according to the present embodiment, a calcium supply / reaction tank 110 for supplying calcium to the first dissolved matter of the wastewater to be treated introduced from the first precipitation tank 104 is formed.

In the calcium supply / reactor 110, calcium is supplied to the first dissolved matter of the wastewater to be treated, for example, in the form of calcium hydroxide [Ca (OH) ₂ ], whereby the first calcium By reacting with about 70% of the fluorine remaining in the dissolved substance, most of the fluorine component in the wastewater to be treated can be precipitated and removed. In addition, the calcium reacts with about 22% of the phosphorus component remaining in the first dissolved solution, so that about 22% of the phosphorus component remaining in the wastewater to be treated is also treated with hydroxylapatite [Ca ₁₀ (PO ₄ ) ₆ (OH). ) ₂ ] can be precipitated and removed mostly in the form of crystals.

As described above, when the wastewater treatment apparatus of the present embodiment passes through the calcium supply / reaction tank 110, most nitrogen, phosphorus, and fluorine components in the wastewater to be treated during the semiconductor manufacturing process may be precipitated and removed. .

In addition, in removing the fluorine component in the wastewater to be treated, in this embodiment, after removing about 30% of the fluorine component from the struvite crystallization reactor 104, the remaining about 70% in the calcium supply / reactor 110 Since only the fluorine component is removed, the calcium supply amount in the calcium supply / reactor 110 is also significantly reduced, which enables to efficiently and economically treat wastewater to be treated.

Meanwhile, the calcium supply amount in the calcium supply / reaction tank 110 is obvious to those skilled in the art in consideration of the concentration of the fluorine component in the wastewater to be treated and the concentration of the fluorine component that has already been precipitated and removed in the struvite crystallization reactor 104. You can decide.

In addition, in the wastewater treatment apparatus of the present embodiment, a second liquid connected to the calcium supply / reactor 110 to solid-liquid separate the first dissolved substance of the wastewater to be treated from the second solid substance and the second dissolved substance. Precipitation tank 112 is formed.

That is, in the second precipitation tank 112, about 22% of the residual phosphorus component and about 70% of the fluorine component precipitated in the calcium supply / reactor 110 are separated and removed from the wastewater to be treated as a second solid. In addition, since the second dissolved substance of the wastewater to be treated, except for this, is almost completely removed because of high concentrations of nitrogen, phosphorus, and fluorine components, the second dissolved solution is discharged to the outside through the outlet portion 116 connected to the second precipitation tank 112. Discharged.

On the other hand, the second solids are conveyed to the calcium supply / reaction tank 110 by a second conveying line 114 connected between the second precipitation tank 112 and the calcium supply / reaction tank 110. The second solid returned in this way is reprocessed in the calcium supply / reactor 110, thereby reducing the amount of calcium required in the calcium supply / reactor 110 and simultaneously removing fluorine from the wastewater to be treated. It is possible to maximize, and ultimately to minimize the amount of sludge remaining after the treatment of the wastewater to be treated, it is possible to improve the efficiency of the wastewater treatment apparatus of this embodiment.

When the industrial wastewater containing high concentrations of nitrogen, phosphorus, and fluorine components is treated with the wastewater treatment apparatus of the present embodiment, nitrogen, phosphorus in the industrial wastewater is precipitated through a struvite crystallization reaction and precipitation of calcium and fluorine. And most of the fluorine component can be removed. In particular, the removal of such nitrogen, phosphorus and fluorine components becomes very efficient and economical, and in particular, industrial wastewater generated during the semiconductor manufacturing process can be effectively treated.

As described above, according to the present invention, industrial wastewater containing high concentrations of nitrogen, phosphorus and fluorine components, in particular, industrial wastewater generated in a semiconductor manufacturing process can be efficiently and economically treated.

Claims (5)

Wastewater to be treated, magnesium (Mg) compound, phosphoric acid (PO ₄ ) compound And an inlet for supplying an alkaline agent, A struvite crystallization reactor connected to the inflow unit to generate a struvite crystallization reaction to the wastewater to be treated; A first precipitation tank for solid-liquid separation of the wastewater to be treated crystallized in the struvite crystallization tank into a first solid and a first dissolved matter; A calcium supply / reaction tank for supplying calcium to the first dissolved matter of the wastewater to be treated introduced from the first precipitation tank, A second precipitation tank for solid-liquid separation of the first dissolved material of the wastewater to be treated introduced into the calcium supply / reaction tank into a second solid material and a second dissolved material; A wastewater treatment apparatus comprising an outlet connected to the second settling tank for discharging the second dissolved matter. The method of claim 1, A first conveying line connected between the first precipitation tank and the struvite crystallization reactor to return the first solid to the struvite crystallization reactor; And a second conveying line connected between the second precipitation tank and the calcium supply / reaction tank to return the second solids to the calcium supply / reaction tank. The method according to claim 1 or 2, And a flow rate adjusting tank which is formed between the inlet portion and the struvite crystallization reaction tank to adjust a supply flow rate and a nitrogen load rate of the wastewater to be treated supplied to the struvite crystallization reaction tank. The wastewater, magnesium-based compound, and phosphoric acid-based compound according to claim 1 or 2, wherein And a waste water treatment device in which a predetermined amount of air is supplied through the inflow portion together with an alkali agent. The wastewater treatment apparatus according to claim 1 or 2, wherein the wastewater to be treated is wastewater containing nitrogen, phosphorus and fluorine components discharged from a semiconductor manufacturing process.

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