Water treatment system using PFR or CSTR and Air Dissolved floation tank

Abstract

The present invention comprises a PFR reactor (110) having a reaction section formed by a pipe having a multilayer wave structure so that wastewater flowing into a wastewater inlet (111) is guided in a zigzag manner, wherein the lower part where the wastewater inlet (111) is located is provided with a coagulation / neutralization reaction section (110a) in which an inorganic coagulant and a neutralizing agent are introduced from the lower part where the wastewater inlet (111) is located to a middle part, and the coagulation reaction section (110b) in which an organic coagulant is introduced from the middle part where the reaction water outlet (123) is located to the upper part; a pressurized flotation tank (200) that removes the coagulated sludge of the reaction water by floating it when the reaction water flows into the wastewater inlet (201) through the reaction water outlet (123) of the PFR reactor (110); and a circulation pump (300) installed on a circulation water line (301) connected to the rear of the pressurized flotation tank (200) to pressurize the treated water of the pressurized flotation tank (200) and supply it to a dissolution tank (400). The water treatment system is characterized by a reactor and a pressurized flotation tank, comprising a dissolution tank (400) that supplies air-mixed dissolved water to a pressurized flotation tank (200).

Description

Technology Field

[0001] The present invention relates to a wastewater treatment system using a reactor and a pressurized flotation tank, and in particular, to a water treatment system using a reactor and a pressurized flotation tank that can increase the stability of sludge treatment by maximizing the coagulation efficiency of suspended solids contained in the influent water using a PFR reactor or a CSTR reactor and a flotation tank even when the concentration of suspended solids in the influent wastewater is high or the flow rate fluctuation is severe, and can easily respond to changes in the water quality of the influent wastewater. Background Technology

[0003] In general, if water containing various pollutants discharged from industrial and livestock facilities—namely, sewage and wastewater (hereinafter collectively referred to as 'wastewater')—is discharged as is, it becomes a major cause of water, soil, and air pollution; therefore, wastewater must be purified and discharged as clean water.

[0004] A wastewater treatment device that treats various pollutants contained in wastewater uses a flotation tank when the incoming wastewater contains a lot of light sludge, and uses a sedimentation tank when the incoming wastewater contains a lot of heavy sludge.

[0005] Since the present invention is a wastewater treatment device related to a flotation tank, only the flotation tank will be described below.

[0006] A wastewater treatment device using a flotation tank is a solid / liquid separation device that allows wastewater introduced through a wastewater inlet to flow horizontally toward the rear, whereby sludge—a suspended solid that is lighter than water and rises to the top of the flotation tank—is removed, and sludge that does not rise and sinks is collected in a hopper and then removed.

[0007] Among these flotation tanks, there is a pressurized flotation tank that increases the flotation efficiency of sludge material by injecting microbubbles into the incoming wastewater and utilizing the buoyancy force of the bubbles.

[0008] As prior art for a wastewater treatment device using such a flotation tank, there is the Korean Registered Patent Publication No. 10-2045911 (published on November 18, 2019), 'Flotation separation type wastewater treatment device capable of controlling air volume,' disclosed in Patent Document 1 of the prior art literature below.

[0009] Another prior art is the Korean Registered Patent Publication No. 10-2665092 (published May 10, 2024), disclosed in Patent Document 2 below, titled ‘Wastewater treatment system equipped with pressurized water generation filtration and microbubble generation control functions of a pressurized flotation tank.’

[0010] In addition, to increase wastewater treatment efficiency, a coagulation reactor is used to coagulate and separate foreign substances such as various sludge, pigments, organic matter, microorganisms, and suspended particles contained in the wastewater before sending the wastewater to the flotation tank.

[0011] Prior art regarding such a coagulation reactor includes the ‘wastewater treatment apparatus for polymerization toner and method for treating wastewater for polymerization toner’ disclosed in Korean Patent Publication No. 10-2011-0124581 (published November 17, 2011) in Patent Document 3 below.

[0012] Another prior art is the 'plug flow coagulation reactor for wastewater treatment' disclosed in Korean Registered Patent Publication No. 10-1438417 (published September 24, 2014) in Patent Document 4 below. Prior art literature

[0014] Korean Registered Patent Publication No. 10-2045911 (Published Nov. 18, 2019) 'Flotation separation type wastewater treatment device capable of air volume control' Korean Registered Patent Publication No. 10-2665092 (Published May 10, 2024) 'Wastewater treatment system equipped with pressurized water generation filtration and microbubble generation control functions of a pressurized flotation tank' Korean Published Patent Publication No. 10-2011-0124581 (Published Nov. 17, 2011) 'Wastewater treatment device for polymerization toner and method for treating wastewater of polymerization toner' Korean Registered Patent Publication No. 10-1438417 (Published Sep. 24, 2014) 'Plug flow coagulation reactor for wastewater treatment' The problem to be solved

[0015] The above patent documents 1, 2, 3, and 4 are single-facility patents, which have the problem of being difficult to configure for optimal treatment efficiency, and the problem of reduced coagulation reaction efficiency because the timing and amount of chemical injection in the coagulation reaction tank are arbitrarily injected.

[0016] In addition, since the dissolved water containing air is supplied in equal amounts throughout the entire interior of the flotation tank through the wastewater inlet, there is a problem in that it is difficult to respond to changes in the quality of the treated water in different parts of the flotation tank.

[0017] The present invention was developed to solve the problems of the conventional and prior art as described above. The objective of the present invention is to provide a water treatment system comprising a reactor and a flotation tank that can enhance the wastewater treatment effect by increasing the efficiency of neutralization and coagulation reactions through the appropriate adjustment of the timing of chemical injection according to the pH concentration of the reaction water, while providing a PFR reactor or a CSTR reactor for the pretreatment of wastewater flowing into the flotation tank.

[0018] Another objective of the present invention is to provide a water treatment system using a reactor and a flotation tank that can easily respond to changes in the water quality of incoming wastewater by increasing the dissolution rate of air flowing into the air dissolution tank and adjusting the inflow amount of air-dissolved water according to the part of the flotation tank. means of solving the problem

[0020] To achieve the above objective, one embodiment of the present invention is characterized by a water treatment system comprising a reactor and a pressurized flotation tank, wherein the reaction section is provided with a pipe having a multilayer wave structure so as to guide the incoming wastewater in a zigzag manner, and the coagulation / neutralization reaction section is provided from the lower part where the wastewater inlet is located to a middle part where an inorganic coagulant and a neutralizing agent are introduced, and the coagulation reaction section is provided from the middle part where the reaction water outlet is located to the upper part where an organic coagulant is introduced; a pressurized flotation tank that removes the coagulated sludge of the reaction water by floating it when the reaction water flows into the wastewater inlet through the reaction water outlet of the PFR reactor; a circulation pump that supplies the treated water at the rear of the pressurized flotation tank to a dissolution tank; and a dissolution tank that supplies the dissolved water mixed with air to the pressurized flotation tank.

[0021] Another embodiment of the present invention is characterized by comprising: a CSTR reactor having two tanks, a coagulation / neutralization tank and a coagulation tank, or three tanks, a coagulation tank, a neutralization tank and a coagulation tank, wherein an inorganic coagulant and a neutralizing agent are introduced together or separately in the front treatment tank and an organic coagulant is introduced in the rear treatment tank; a pressurized flotation tank that removes coagulated sludge from the reaction water by floating it when reaction water flows in through the CSTR reactor; a circulation pump that sends the treatment water at the rear of the pressurized flotation tank to a dissolution tank; and a dissolution tank that supplies dissolved water to the pressurized flotation tank by mixing air supplied from a compressor with circulating water supplied through the circulation pump.

[0022] In addition, at the end of the above coagulation / neutralization reaction section, a pH sensor is provided to measure the pH concentration, and the neutralizing agent is either introduced or stopped according to the measured pH concentration; further, the system is characterized by having a coagulation tank for a CSTR reactor in which an organic coagulant is supplied between the PFR reactor and the pressurized flotation tank.

[0023] In addition, the pressurized flotation tank is characterized by having a plurality of dissolving water holes on both the left and right sides centered on the wastewater inlet, and by installing a dissolving water distribution pipe at the dissolving water outlet of the dissolving tank, wherein a plurality of dissolving water distribution ports, each opened and closed by a valve, are connected to the above-mentioned dissolving water holes. Effects of the invention

[0025] In this invention, equipping a PFR reactor as a pretreatment device for a pressurized flotation tank provides an environment in which flocs can be sequentially formed and grown over time after the coagulant is injected, thereby minimizing floc destruction caused by shear force and enabling the formation of uniform and robust flocs.

[0026] Furthermore, equipping a CSTR reactor as a pretreatment device for a pressurized flotation tank has the effect of increasing the stability of flotation treatment even when the concentration of influent wastewater is high or flow rate fluctuations are severe, and by maximizing the coagulation efficiency of pollutants in the wastewater, it can enhance the stability of flotation treatment.

[0027] In addition, the pressurized flotation tank can adjust the amount of dissolved water supplied according to the wastewater treatment status in each area of ​​the wastewater dispersion section arranged laterally when sending dissolved water mixed with air from the dissolution tank to the wastewater flowing in through the wastewater inlet, thus making it easy to effectively respond to changes in water quality in each area. Brief explanation of the drawing

[0029] FIG. 1 is a diagram showing the treatment system of a PFR reactor and a flotation tank in which the present invention is implemented. FIG. 2 is a schematic diagram of FIG. 1 in which a CSTR reactor is installed between the PFR reactor and the flotation tank. FIG. 3 is a diagram showing the treatment system of the CSTR reactor and flotation tank in which the present invention is implemented. FIG. 4 is a drawing showing that the CSTR reactor of the present invention is composed of three sets. FIG. 5 is a side view of a pressurized flotation tank with a dissolution tank installed in the present invention. FIG. 6 is a top view of the pressurized flotation tank of the present invention. FIG. 7 is a plan view of a structure in which a melting tank of the present invention and a pair of circulation pumps are connected. FIG. 8 is a drawing showing the PFR reactor of the present invention as another embodiment. FIG. 9 is a drawing showing an orifice installed on one reaction line of the PFR reactor of the present invention. Specific details for implementing the invention

[0030] The floating sludge removal unit of a pressurized flotation system and the method of installing the same according to a preferred embodiment of the present invention will be described in detail below with reference to the attached drawings.

[0031] The following description regarding the present invention is merely an example for structural or functional explanation, and therefore the scope of the present invention should not be interpreted as being limited by the examples specified in the text. That is, since the examples can be modified in various ways and can take various forms, the scope of the present invention should be understood to include equivalents capable of realizing the technical concept.

[0032] Furthermore, the purposes or effects presented in this invention do not imply that specific embodiments must include all of them or only such effects; therefore, the scope of the rights of this invention should not be understood as being limited by them.

[0033] FIG. 1 is a diagram showing a treatment system diagram of a PFR reactor and a flotation tank in which the present invention is implemented, FIG. 2 is a diagram showing a CSTR reactor installed between the PFR reactor and the flotation tank in FIG. 1, and FIG. 3 is a diagram showing a treatment system diagram of a CSTR reactor and a flotation tank in which the present invention is implemented, and these are described by example as follows.

[0035] <1st Example> Water treatment system using a PFR reactor and a pressurized flotation tank

[0036] The processing system of the present invention using plug flow illustrated in FIG. 1 is characterized by being composed of a PFR reactor (Plug Flow Reactor) (110), a pressurized flotation tank (200), a circulation pump (300), and a dissolution tank (400).

[0037] The above PFR reactor (110) is provided with first and second chemical inlets at the bottom inlet where the wastewater inlet (111) is located, through which an inorganic coagulant and a neutralizing agent are introduced from an inorganic coagulant tank (10) and a neutralizing agent tank (20), thereby forming a coagulation / neutralization reaction section (110a) up to a certain point, and at the point where the coagulation / neutralization reaction section (110a) ends, it is provided with a third chemical inlet through which an organic coagulant is introduced from an organic coagulant automatic dissolving device (30), thereby forming a coagulation reaction section (110b) up to the reaction water outlet (123).

[0038] Here, at the leading edge of each layer of the reaction section having a multilayer wave structure, a number of reaction water sample collection parts (113) are provided for each layer to receive reaction water samples, so that the pH concentration of the reaction water collected as a sample can be checked.

[0039] The above pressurized flotation tank (200) is a treatment tank in which, when reaction water flows into the wastewater inlet (201) through the reaction water outlet (123) of the PFR reactor (110), the flocculated sludge of the reaction water is floated, and the floated sludge is pushed backward by a skimmer installed in a circulating rotational manner on the upper part of the pressurized flotation tank (200) and falls into a sludge collection tank.

[0040] The above circulation pump (300) is installed on a circulation water line (301) connected to the rear of the pressurized flotation tank (200), and pressurizes the treated water of the pressurized flotation tank (200) and supplies it to the dissolution tank (400).

[0041] The above-mentioned dissolution tank (400) mixes air supplied through a compressor (410) and circulating water supplied through a circulation pump (300) internally using a mixing means such as a screw to produce dissolved water in which air is dissolved, and supplies the dissolved water to a pressurized flotation tank (200) through a dissolved water outlet (401).

[0042] In the drawing, the unexplained reference numeral (41) is a first pump that supplies an inorganic coagulant from an inorganic coagulant tank (10) to a coagulation / neutralization reaction section (110a), (42) is a second pump that supplies a neutralizing agent from a neutralizing agent tank (20) for pH adjustment to a coagulation / neutralization reaction section (110a), (30) is an organic coagulant automatic dissolving device, and (43) is a third pump that supplies an organic coagulant from an organic coagulant automatic dissolving device (30) to a coagulation reaction section (110b).

[0043] In the present invention formed in this manner, the PFR reactor (110) generally allows the fluid within the reactor to move like a plug, and while perfect mixing occurs within each plug, there is almost no mixing between plugs, and all fluids have almost the same residence time.

[0044] When the inorganic coagulant from the inorganic coagulant tank (10) is introduced into the wastewater introduced through the wastewater inlet (111) of the PFR reactor (110) via the first pump (41), an environment is provided in which flocs can be formed and grown sequentially over time, which is advantageous for minimizing floc destruction by shear force and forming uniform and solid flocs, which contributes to increasing the solid-liquid separation efficiency in the flotation tank.

[0045] And when alkali is introduced as a neutralizing agent through the second pump (42), the wastewater undergoes coagulation and neutralization reactions while passing through the coagulation / neutralization reaction section (110a) up to the middle section of the reaction section of the PFR reactor (110).

[0046] Here, if the operator visually determines the pH concentration of the reaction water sample collected through the reaction water sample collection unit (113) of the coagulation / neutralization reaction section (110a) and adjusts the amount of inorganic coagulant and neutralizing agent added, the coagulation and neutralization reactions of the wastewater proceed well.

[0047] And at the end of the coagulation / neutralization reaction section (110a), a reaction water sample collection section (113a) is provided in front of the third chemical inlet, and a pH sensor (114) connected to the reaction water sample collection section (113a) for measuring pH concentration is provided.

[0048] Accordingly, when the reaction water in which the condensation and neutralization reactions have proceeded as described above reaches the end of the condensation / neutralization reaction section (110a), the pH concentration value of the reaction water measured through the pH sensor (114) connected to the reaction water sample collection section (113a) is transmitted to the control unit.

[0049] Then, the control unit checks with the pH sensor (114), and if the pH concentration of the reaction water flowing into the coagulation reaction section (110b) is lower than the standard of 7±1, it operates the second pump (42) for a certain period of time to add more neutralizing agent.

[0050] And, when the pH concentration of the measured reaction water is measured to be higher than the standard of 7±1, the operation of the second pump (42) is stopped upon receiving a signal from the control unit and the injection of the neutralizing agent is stopped, so the reaction water is moved to the coagulation reaction section (110b) in a state where the neutralization reaction is optimal.

[0051] And in the coagulation reaction section (110b), the organic coagulant dissolved from the organic coagulant automatic dissolving device (30) is supplied to the third pump (43), so while passing through the coagulation reaction section (110b), the reaction water undergoes a coagulation reaction of the suspended solid, sludge.

[0052] In addition, the operator can visually observe and judge the flocculation state of the reaction water collected from the reaction water sample collection unit (113) at the very end and adjust the amount of organic coagulant to be added.

[0053] Then, the reaction water, in which the sludge aggregation reaction is well generated, is supplied to a pressurized flotation tank (200) through a wastewater inlet (201) connected to a reaction water outlet (123). And within the pressurized flotation tank (200), the aggregated sludge of the wastewater (reaction water) can float well, so that sludge removal can proceed quickly.

[0054] These PFR reactors enable multi-stage mixing through gradient mixing, which facilitates coagulant dispersion with strong stirring during the initial coagulation phase and subsequently induces floc growth with gradually weaker stirring. This is considered crucial for optimizing floc quality prior to flotation treatment.

[0055] This PFR reactor (100) can increase the number of stages to 6 or more when the pH change of the influent is large, and reduce the number of stages to at least 4 when the pH change is small, thus allowing for an increase or decrease in the number of stages.

[0056] That is, FIG. 8 is a drawing showing the PFR reactor of the present invention configured with six layers as an example, with each layer connected by a flange, and FIG. 9 is a drawing showing an orifice installed between the flanges in FIG. 8.

[0057] The PFR reactor (110) described herein is also equipped with first and second chemical inlets into which an inorganic coagulant and a neutralizing agent are introduced, forming a coagulation / neutralization reaction section (110a) up to a certain area, and is equipped with a third chemical inlet into which an organic coagulant is introduced at the point where the coagulation / neutralization reaction section (110a) ends, forming a coagulation reaction section (110b) up to the reaction water outlet (123).

[0058] In addition, at the leading edge of each layer of the above-mentioned reaction section, a reaction water sample collection unit (113) is provided for each layer to receive a reaction water sample, so that the pH concentration of the reaction water passing through each layer can be checked.

[0059] The feature here is that the piping for each layer is connected to both flanges (115a) (115b), and a flow rate increasing orifice (116) is provided between both flanges (115a) (115b) at every part where flow rate is required, and both sides of the orifice (116) are kept sealed by a gasket (117), and such an orifice (116) is applied as is to a 5-layer PRR reactor.

[0060] As described above, in the place where the orifice (116) is installed, the orifice (116) increases the flow rate of the reaction water passing through the piping of the corresponding part, so it can be installed at every layer where an increase in flow rate is required to quickly produce reaction water with enhanced coagulation, neutralization, and coagulation effects.

[0061] Here, as shown in FIGS. 1 and 3, it is preferable that the reaction section length of the coagulation / neutralization reaction section (110a) be formed to be at least 1.5 to 3 times the length of the reaction section of the coagulation reaction section (110b).

[0062] If the length of the reaction section of the coagulation / neutralization reaction section (110a) is less than 1.5 times shorter than the length of the reaction section of the coagulation reaction section (110b), the coagulation / neutralization reaction of the treated water often does not occur as desired, and if it exceeds 3 times, there is little effect in enhancing the coagulation / neutralization reaction, while the manufacturing cost increases due to the increased size of the PFR reactor (110).

[0063] The present invention may further include a coagulation tank (122) of a CSTR reactor (Continuous Stirred Tank Reactor) in which an organic coagulant is supplied between the PFR reactor (110) and the pressurized flotation tank (200) as shown in FIG. 2.

[0064] Then, the reaction water in which sludge is coagulated in the coagulation reaction section (110b) of the PFR reactor (110) is supplied with an organic coagulant, and the sludge is coagulated once more by a stirring fan rotating at a low speed of 60±10 RPM in the coagulation tank (122) for the CSTR reactor, and then supplied to the pressurized flotation tank (200), so that the removal of floating sludge in the pressurized flotation tank (200) can proceed more effectively.

[0065] Here, the organic coagulant automatic dissolving device (30) comprises: a coagulant storage unit (31) in which a certain amount of organic coagulant filled inside is dropped to the outlet by a conveying unit (35); a coagulant water tank (32) installed at the bottom of the coagulant storage unit (31) through which the organic coagulant falling from the coagulant storage unit (31) falls into the filled water, and which has an internal passage provided in a zigzag shape; and a plurality of stirrers (33) installed in the coagulant water tank (32) to be operated by a motor (34), which stir the organic coagulant dropped into the water of the coagulant water tank (32) to make organic coagulant water.

[0066] The above organic coagulant automatic dissolving device (30) is preferably designed so that the organic coagulant dissolved in the organic coagulant water can be supplied to the PFR reactor (110) and the CSTR reactor (120) in common through the third pump (43), so that each dissolving device does not need to be installed separately.

[0067] In addition, a circulation pump (300) installed on a circulation water line (301) connected to the rear of the pressurized flotation tank (200) pressurizes the treated water at the rear of the pressurized flotation tank (200) and supplies it to the dissolution tank (400). The dissolution tank (400) supplies the dissolved water, which is made by mixing the air supplied from the compressor (410) and the treated water supplied through the circulation pump (300), to the wastewater flowing in through the dissolution water outlet (401), thereby increasing the flotation force of the aggregated sludge.

[0069] <2nd Example> Water treatment system using a CSTR reactor and a pressurized flotation tank

[0070] As shown in FIG. 3, the wastewater treatment system of the present invention using a CSTR reactor (Continuous Stirred Tank Reactor) is characterized by being composed of a CSTR reactor (120), a pressurized flotation tank (200), a circulation pump (300), and a dissolution tank (400).

[0071] The above CSTR reactor (120) may be equipped with two tanks, a coagulation / neutralization tank (121) and a coagulation tank (122), as shown in FIG. 3, or with three tanks, a coagulation tank (121a), a neutralization tank (121b), and a coagulation tank (122), as shown in FIG. 4.

[0072] And the above CSTR reactor (120) has a stirring fan installed to be driven by a motor for each treatment tank, which rotates to evenly stir the wastewater flowing into each treatment tank and the added chemicals.

[0073] Here, in the case of two reaction tanks, it is desirable to add an inorganic coagulant and a neutralizing agent together to the influent wastewater in the front reaction tank and an organic coagulant to the rear reaction tank, and in the case of three reaction tanks, to add an inorganic coagulant and a neutralizing agent to the front two reaction tanks respectively and an organic coagulant to the rear reaction tank so that the sludge coagulation, neutralization, and coagulation reactions of the wastewater are achieved.

[0074] That is, in the case of general wastewater, the coagulation time of suspended solids such as sludge can be short, so one tank may be configured as a coagulation / neutralization tank (121) in which an inorganic coagulant and a neutralizing agent are introduced together to perform coagulation / neutralization together, and the other tank may be configured as a coagulation tank (122) in which an organic coagulant is introduced to coagulate the suspended solids, such as sludge.

[0075] And in the case of heavy metal wastewater, since the coagulation time is long and coagulation must be done well, it is preferable to have three tanks, each equipped with a coagulation tank (121a) into which an inorganic coagulant is introduced, a neutralization tank (121b) into which a neutralizing agent is introduced, and a coagulation tank (122) into which an organic coagulant is introduced, as shown in FIG. 4.

[0076] The stirring fan, driven by a motor installed in each of the above-mentioned tanks, rotates at a speed of approximately 120 to 180 RPM in the case of the two-tiered coagulation / neutralization tank (121), at approximately 170 to 180 RPM in the three-tiered coagulation tank (121a), and at approximately 120 to 180 RPM in the neutralization tank (121b), thereby effectively stirring the inorganic coagulant and neutralizing agent introduced into the wastewater, so that optimal coagulation and neutralization reactions occur.

[0077] And each coagulation tank (122) in the 2nd and 3rd groups rotates at a low speed of about 60±10 RPM, allowing the organic coagulant being injected to dissolve well in the wastewater, thereby causing an optimal coagulation reaction to occur.

[0078] As described in detail in the wastewater treatment system of the above <1st embodiment>, the organic coagulant dissolved in the organic coagulant automatic dissolving device (30), which consists of a coagulant storage unit (31), a coagulant water tank (32), and a stirrer (33), is supplied to the coagulation tank (122) through the third pump, and then causes a coagulation reaction of the suspended solid sludge in the coagulation tank (122).

[0079] Due to the characteristic that the inorganic coagulant, neutralizing agent, and organic coagulant are perfectly mixed in the wastewater in each treatment tank, the water quality flowing into the pressurized flotation tank can be maintained relatively uniformly even if there are significant fluctuations in the concentration or flow rate of the influent wastewater, thus providing high stability and efficiency for subsequent flotation treatment, and it is easy to control the amount of chemical injected because it is possible to maintain a uniform concentration throughout the reactor when the coagulant is injected.

[0080] And the above CSTR reactors (120), which are installed in two or three sets, can be flexibly arranged as needed because connecting them in series increases the reaction time and produces an effect similar to that of a PFR reactor (110).

[0081] When the reaction water flows into the wastewater inlet (201) through the reaction water outlet (123) of the CSTR reactor (120) as described above, the pressurized flotation tank (200) can effectively float and remove the aggregated sludge of the reaction water.

[0082] And a circulation pump (300) installed on a circulation water line (301) connected to the rear of the pressurized flotation tank (200) pressurizes the treated water at the rear of the pressurized flotation tank (200) and supplies it to the dissolution tank (400) for circulation.

[0083] The above dissolution tank (400) supplies the dissolved water, which is produced by mixing air supplied from the compressor (410) and treated water supplied through the circulation pump (300), to the pressurized flotation tank (200) through the dissolved water outlet (401). Therefore, in the pressurized flotation tank (200), the aggregated sludge rises more smoothly and can be easily removed by the flotation sludge remover in which the skimmer rotates.

[0085] In the wastewater treatment system of the first and second embodiments above, the pressurized flotation tank (200) may have a transversely elongated wastewater dispersion section (210) on the inner surface of the wastewater inlet (201), and may have a plurality of dissolving water holes (220) communicating with the wastewater dispersion section (210) on both the left and right sides centered on the wastewater inlet (201).

[0086] And at the dissolution water outlet (401) of the dissolution tank (400), a dissolution water distribution pipe (420) may be installed, which is equipped with a plurality of dissolution water distribution ports (421) that are each opened and closed by a valve and connected to the above-mentioned dissolution water hole (220).

[0087] Then, the amount of dissolved water supplied can be varied according to the wastewater treatment state for each part dispersed in the wastewater dispersion section (210) of the pressurized flotation tank (200), making it easy to effectively respond to changes in water quality for each part.

[0088] In addition, the pressurized flotation tank (200) is installed on the base plate (230) so that a predetermined space is provided between it and the base plate (230), and the circulation pump (300) installed on the circulation water line (301) is installed within the space to minimize the volume.

[0089] And at this time, two units may be installed in parallel within the aforementioned predetermined space, with one serving as the main pump and the other as the spare pump.

[0090] Then, even if the main pump fails, the process of supplying the dissolved water to the wastewater dispersion unit by continuously circulating the treated water of the pressurized flotation tank (200) to the dissolution tank (400) through the spare pump can be carried out without interruption, and maintenance work such as repairing or replacing the main pump that failed can be performed, thereby increasing the treatment efficiency of the pressurized flotation tank.

[0091] Although the invention made by the inventors has been specifically described according to the above embodiments, it is obvious to those skilled in the art that the invention is not limited to the above embodiments and can be modified in various ways without departing from the gist thereof. Explanation of the symbols

[0093] 10: Inorganic coagulant tank 20: Neutralizer tank 30: Automatic organic coagulant dissolving device 31: Coagulant storage unit 32 : Coagulation water tank 33 : Stirrer 34 : Motor 35 : Transfer unit 41,42,43: 1st, 2nd, and 3rd pumps 110: PFR reactor 110a: Coagulation / neutralization reaction section 110b: Coagulation reaction section 111: Wastewater inlet 112: Reaction water outlet 113, 113a: Reaction water sampling section 114: pH sensor 115a, 115b: Flange 116 : Orifice 117 : Gasket 120: CSTR reactor 121: Coagulation / neutralization tank 200: Pressurized flotation tank 201: Wastewater inlet 210 : Wastewater Dispersion Section 220 : Dissolving Water Hole 230 : Base plate 300: Circulation pump 301: Circulating water line 400 : Dissolution water tank 401 : Dissolution water outlet 410 : Compressor 420 : Dissolved water distribution 421 : Dissolved water distribution port

Claims

Claim 1 A PFR reactor (110) is provided with a reaction section formed by a pipe having a multilayer wave structure so that wastewater flowing into the wastewater inlet (111) is guided in a zigzag manner, wherein at the lower inlet where the wastewater inlet (111) is located, first and second chemical inlets are provided for introducing an inorganic coagulant and a neutralizing agent from an inorganic coagulant tank (10) and a neutralizing agent tank (20), thereby forming a coagulation / neutralization reaction section (110a) up to a certain part, and at the point where the coagulation / neutralization reaction section (110a) ends, a third chemical inlet is provided for introducing an organic coagulant from an organic coagulant automatic dissolving device (30), thereby forming a coagulation reaction section (110b) up to the reaction water outlet (123); and when reaction water flows into the wastewater inlet (201) through the reaction water outlet (123) of the PFR reactor (110), pressurization is provided to float and remove the coagulated sludge of the reaction water. The system is composed of a flotation tank (200); a circulation pump (300) that pressurizes the treated water at the rear of the pressurized flotation tank (200) and supplies it to a dissolution tank (400); and a dissolution tank (400) that supplies air-mixed dissolution water to the pressurized flotation tank (200). The pressurized flotation tank (200) is provided with a wastewater dispersion section (210) on the inner surface of the wastewater inlet (201), and a plurality of dissolution water holes (220) communicating with the wastewater dispersion section (210) are provided on both the left and right sides centered on the wastewater inlet (201). A dissolution water distribution pipe (420) is installed at the dissolution water outlet (401) of the dissolution tank (400), with a plurality of dissolution water distribution ports (421) each opened and closed by a valve connected to the above dissolution water holes (220), thereby allowing the amount of dissolution water supplied to each part to be adjusted according to the wastewater treatment state to respond to changes in water quality. A water treatment system using a reactor and a pressurized flotation tank, characterized in that the reactor (110) has pipes connected to both flanges (115a) and (115b) for each layer, and has an orifice (116) for increasing flow velocity between the two flanges (115a) and (115b) for each part where flow velocity is required, so that the flow velocity of the reaction water passing through the pipes in that part is increased. Claim 2 A CSTR reactor (120) is provided with two tanks, a coagulation / neutralization tank (121) and a coagulation tank (122), or three tanks, a coagulation tank (121a), a neutralization tank (121b), and a coagulation tank (122), wherein an inorganic coagulant and a neutralizing agent are introduced together or separately in the front treatment tank, and an organic coagulant is introduced in the rear treatment tank to cause sludge coagulation, neutralization, and coagulation reactions; a pressurized flotation tank (200) that removes the coagulated sludge of the reaction water by floating it when the reaction water flows into the wastewater inlet (201) through the reaction water outlet (123) of the CSTR reactor (120); a circulation pump (300) that sends the treatment water at the rear of the pressurized flotation tank (200) to a dissolution tank (400); and a dissolution tank (400) that sends the dissolved water mixed with air to the pressurized flotation tank (200); and is composed of pressurized A water treatment system using a reactor and a pressurized flotation tank, characterized in that the flotation tank (200) is provided with a wastewater dispersion section (210) on the inner surface of the wastewater inlet (201), and a plurality of dissolving water holes (220) communicating with the wastewater dispersion section (210) are provided on both the left and right sides centered on the wastewater inlet (201), and a dissolving water distribution pipe (420) is installed at the dissolving water outlet (401) of the dissolving tank (400), wherein a plurality of dissolving water distribution ports (421) that are each opened and closed by a valve are connected to the above dissolving water holes (220), thereby allowing the amount of dissolving water supplied to each part to be adjusted according to the wastewater treatment state to respond to changes in water quality. Claim 3 A water treatment system using a reactor and a pressurized flotation tank according to claim 1, wherein a reaction water sample collection unit (113a) is provided at the end of the coagulation / neutralization reaction section (110a) in front of the third chemical inlet, and a pH sensor (114) connected to the reaction water sample collection unit (113a) is provided, wherein if the pH concentration of the reaction water measured by the pH sensor (114) before flowing into the coagulation reaction section (110b) is lower than the 7±1 standard, a second pump (42) is operated to further inject a neutralizing agent, and if the pH concentration is higher than the 7±1 standard, the second pump (42) is stopped to stop the injection of the neutralizing agent. Claim 4 A water treatment system using a reactor and a pressurized flotation tank according to claim 1, further comprising a coagulation tank (122) for a CSTR reactor in which an organic coagulant is supplied between the PFR reactor (110) and the pressurized flotation tank (200), so that the reaction water coagulated in the coagulation reaction section (110b) of the PFR reactor (110) passes through the coagulation tank (122) and is supplied to the pressurized flotation tank (200) so as to increase the coagulation efficiency of the sludge. Claim 5 A water treatment system comprising a reactor and a pressurized flotation tank, wherein, in claim 1 or claim 2, the organic coagulant automatic dissolution device (30) comprises: a coagulant storage unit (31) in which an organic coagulant filled inside is dropped to an outlet by a transfer unit (35) for the injection of an organic coagulant; a coagulant water tank (32) installed at the bottom of the coagulant storage unit (31) through which the organic coagulant dropped from the coagulant storage unit (31) falls into the filled water, and which has an internal passage provided in a zigzag shape; and a stirrer (33) installed in the coagulant water tank (32) to be operated by a motor (34), which stirs the organic coagulant dropped into the water of the coagulant water tank (32) to make organic coagulant water. Claim 6 delete Claim 7 A water treatment system using a reactor and a pressurized flotation tank according to claim 1 or claim 2, wherein the pressurized flotation tank (200) is installed on the base plate (230) such that a predetermined space is provided between it and the base plate (230), and the circulation pump (300) of the circulation water line (301) is provided with two pumps, a main pump and a spare pump, and the two pumps are arranged in parallel within the space on the base plate (230) to minimize the volume and allow for continued operation even in the event of a main pump failure. Claim 8 delete Claim 9 A water treatment system according to claim 1, characterized in that the reaction section length of the coagulation / neutralization reaction section (110a) is formed to be at least 1.5 to 3 times the length of the reaction section of the coagulation reaction section (110b).

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