KR102782095B1 - Wastewater treatment system using constructed wetland capable of injecting carbon sources for denitrification - Google Patents

Abstract

The present invention relates to a water treatment system using an artificial wetland capable of injecting a carbon source for denitrification into a flooded zone, the artificial wetland including a vertical flow type artificial wetland having a non-submerged upper zone and a flooded lower zone and having water purification plants planted therein for nitrification-denitrification treatment of wastewater, wherein the vertical flow type artificial wetland further includes a direct path extending from the upper zone to the lower zone for injecting a carbon source for denitrification into the flooded lower zone.

Description

{WASTEWATER TREATMENT SYSTEM USING CONSTRUCTED WETLAND CAPABLE OF INJECTING CARBON SOURCES FOR DENITRIFICATION}

The present invention relates to a technology for treating wastewater using an artificial wetland.

Artificial wetlands are wetlands that are artificially created to improve natural purification mechanisms for the purposes of water purification, securing ecological habitats, securing water resources and flood control, landscaping and recreational functions, climate control, and environmental education. In addition to wetland restoration, which restores natural wetlands, artificial wetlands are created for various purposes, and are mainly used for the purpose of water purification to remove pollutants.

These artificial wetlands are classified into free water surface wetlands (FWS), horizontal subsurface flow wetlands (HSSF), vertical flow wetlands (VF), and hybrid wetlands according to their hydrological flow patterns, and are applied independently or in conjunction with each other, taking into account the purpose of creation, properties of inflow water, and available space.

Natural surface flow wetlands are a type of general artificial wetland and are applied when the inflow volume is large and continuous inflow occurs. Free surface flow wetlands have positive effects such as providing habitats for plants and animals and waterside space, but they also have problems such as bad odor, pests, and bird outbreaks due to continuous inflow of pollutants.

Horizontal subsurface flow wetlands are structures in which water flows horizontally through spaces filled with filter media, so they have less odor and pests. However, if pollutants continue to flow in, the pores in the filter media can become clogged, so a small-scale structure with intermittent inflow is appropriate.

Vertical subsurface flow wetlands are similar to horizontal subsurface flow wetlands in terms of using media, but they are systems in which pollutants are introduced from the surface of the artificial wetland to be vertically filtered against the media layer. Water stagnates in the wetland at regular intervals due to water pressure and then flows out, and they have a ventilation principle in which oxygen is supplied to the pores of the media layer due to periodic phenomena. Therefore, nitrification occurs during the filtration process, and denitrification occurs through recirculation. This configuration is very effective in removing nitrogen from wastewater.

Hybrid wetlands are operated in a series or parallel manner by connecting natural surface flow wetlands, horizontal subsurface flow wetlands, and vertical subsurface flow wetlands. They can improve purification efficiency and solve problems such as odor and mosquito habitats to some extent. However, they require relatively large areas and can be very expensive, making them unsuitable for small-scale treatment at the village level.

Meanwhile, wastewater from domestic sewage or various factories, if discharged as is, can cause serious water pollution, so pollutants must be removed to a level that can maintain the natural purification ability before discharge. In particular, wastewater from villages contains organic matter, nitrogen, phosphorus, etc., and these substances must be effectively treated before discharge.

Accordingly, the inventor of the present invention conducted a long period of research and trial and error on how to appropriately configure and combine facilities and devices for removing remaining organic matter, phosphorus, etc., while utilizing a vertical underground flow wetland that can effectively remove nitrogen, etc. contained in village-level wastewater, and finally completed the present invention.

The present invention provides a water treatment system using an artificial wetland capable of injecting a carbon source for denitrification, which can efficiently remove organic matter, nitrogen, phosphorus, etc. contained in village-level wastewater and discharge them.

In addition, a water treatment system using an artificial wetland capable of injecting a carbon source for denitrification to directly supply the carbon source for denitrification that is lacking in the lower part of the artificial wetland, thereby efficiently maximizing the denitrification process is provided.

Meanwhile, other unspecified purposes of the present invention will be additionally considered within a range that can be easily inferred from the following detailed description and its effects.

According to an embodiment of the present invention, a vertical flow type artificial wetland is provided, in which purification plants are planted for nitrification-denitrification treatment of wastewater, and which is composed of a non-submerged upper zone and a submerged lower zone.

The above vertical flow type artificial wetland is,

It is characterized by further including a direct path extending from the top to the bottom for injecting a carbon source for denitrification into the submerged lower zone.

A water treatment system using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area is provided.

According to an embodiment of the present invention, the vertical flow type artificial wetland is

A filter bed filled with gravel, sand, etc., with an internal space consisting of a bottom and side walls made of impermeable material;

A drain formed at the bottom of the filter bed through which wastewater moves; and

It may include a wastewater discharge device connected to the above drain and discharging wastewater.

According to an embodiment of the present invention, a penetrating medium is further included to fill the interior of the direct path,

Wastewater supplied from the top can be delivered downwards through the direct path and then spread to the remaining sections.

According to an embodiment of the present invention, the direct path is

The filter bed may be formed as a pair of partition structures along the length of the filter bed.

According to an embodiment of the present invention, the penetrating media is

It may be composed of gravel of a certain size or larger.

According to an embodiment of the present invention, the filter bed comprises:

It may further include wood chips placed at the bottom to supplement organic matter for denitrification.

According to an embodiment of the present invention, the filter bed comprises:

It may be placed at the bottom and may include at least one filter medium among slag, oyster shell, clay filter medium, and zeolite capable of absorbing phosphorus.

According to another aspect of the present invention, a first step of biological pretreatment of wastewater by a trickling filter; and

In order to treat nitrification and denitrification of wastewater that has passed through the biological pretreatment unit, a second step is included in which water purification plants are planted and water is supplied to the upper part of a vertical flow-type artificial wetland consisting of a non-submerged upper section and a submerged lower section for a certain period of time.

The second step above is,

The above-mentioned wastewater is repeatedly supplied and stopped for a certain period of time to the upper part of the vertical flow-type artificial wetland, and in the case of the stoppage of the second stage, the wastewater is further supplied through a direct path extending from the upper part to the lower part for the purpose of injecting a carbon source for denitrification into the submerged lower part for a certain period of time, characterized in that it includes a step.

A wastewater treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area can be provided.

By using a water treatment system utilizing an artificial wetland capable of injecting a carbon source for denitrification according to the present invention, organic matter, nitrogen, phosphorus, etc. contained in village-level wastewater can be efficiently removed and discharged.

In addition, by using a water treatment system utilizing an artificial wetland capable of injecting a carbon source for denitrification according to the present invention, the carbon source for denitrification that is insufficient in the lower part of the artificial wetland can be directly supplied, thereby efficiently maximizing the denitrification effect.

Meanwhile, it is added that even if an effect is not explicitly mentioned herein, the effect and its provisional effect described in the following specification expected by the technical features of the present invention are treated as described in the specification of the present invention.

Figure 1 is a schematic diagram showing a water treatment system using an artificial wetland according to one embodiment of the present invention.
Figure 2 is a schematic diagram showing a water treatment system using an artificial wetland according to another embodiment of the present invention.
Figure 3 relates to a wastewater treatment method using an artificial wetland according to one embodiment of the present invention.
FIG. 4 is a drawing showing a sprinkler device according to one embodiment of the present invention.
FIG. 5 is a plan view of a vertical flow type artificial wetland according to one embodiment of the present invention.
Figure 6 is a cross-sectional view II of Figure 5.
Figure 7 is a cross-sectional view taken along line II-II of Figure 5.
Figure 8 is a drawing showing a direct path for injection of carbon for denitrification within a flooded area.
Figure 9 is a drawing showing a wastewater treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area according to the present invention.
It is to be understood that the attached drawings are provided for reference only to help understand the technical concept of the present invention, and the scope of the rights of the present invention is not limited thereby.

In describing the present invention, if it is judged that the detailed description of related known functions that are obvious to those skilled in the art and may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprises" or "has" and the like are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

Hereinafter, an embodiment of a water treatment system using an artificial wetland capable of injecting a carbon source for denitrification according to the present invention will be described in detail with reference to the attached drawings. In describing with reference to the attached drawings, identical or corresponding components are assigned the same drawing numbers and redundant descriptions thereof will be omitted.

The wastewater in the present invention may include effluent.

Figure 1 is a schematic diagram showing a water treatment system using an artificial wetland according to one embodiment of the present invention.

As illustrated in FIG. 1, a water treatment system using an artificial wetland according to the present invention may include a receiving unit (300) for receiving wastewater, a biological pretreatment unit (100) for biologically pretreating wastewater, and a vertical flow type artificial wetland (200) for performing a nitrification-denitrification process.

The receiving unit (300) receives wastewater, and at this time, the wastewater may be supplied as filtered wastewater through a pretreatment filter unit (400) as needed. The pretreatment filter unit (400) filters large solid substances with a diameter greater than a certain diameter contained in the wastewater, thereby preventing clogging of the pipes or accumulation of large sediments in the receiving unit (300) during the subsequent process.

The receiving unit (300) may be equipped with a plurality of pumps. It may include a first pump (310) that transports wastewater from the receiving unit (300) to a biological pretreatment unit (100) and a second pump (320) that transports wastewater from the receiving unit (300) to a vertical flow type artificial wetland (200).

The first pump (310) supplies wastewater from the receiving unit (300) to the biological pretreatment unit (100) through the first supply line connecting the receiving unit (300) and the biological pretreatment unit (100).

The second pump (320) supplies wastewater from the receiving unit (300) to the vertical flow artificial wetland (200) through the second supply line connecting the receiving unit (300) and the vertical flow artificial wetland (200).

The second pump (320) can supply wastewater with a relatively greater pressure and capacity than the first pump (310). This is because the amount of wastewater supplied to the vertical flow type artificial wetland (200) is much greater than the amount of wastewater supplied to the biological pretreatment unit (100).

The second pump (320) can optionally be connected to the first supply line to supply wastewater from the receiving unit (300) to the biological pretreatment unit (100). In the biological pretreatment unit (100), the sprinkler (130) rotates to spray wastewater onto the fixed filter medium (110). When wastewater of a larger capacity and pressure is supplied by the second pump (320), the sprinkler (130) can rotate upward to supply wastewater to the upper portion.

In the biological pretreatment unit (100), a cover unit (120) is placed on top of the fixed filter medium (110), and water purifying plants (A) such as reeds can be planted in the cover unit (120), and wastewater can be supplied to the water purifying plants (A) when necessary.

Meanwhile, by configuring the cover part (120) including aquatic plants (A) such as reeds, it is possible to solve problems such as bad odor and pests, and to solve the problem of low water temperature in winter when the temperature drops. In addition, the aquatic plants (A) can absorb carbon, thereby increasing the amount of carbon stored.

A sliding door (121) may be further included between the cover part (120) and the upper part of the fixed bed material (110). The sliding door (121) can open or close the upper part of the fixed bed material (110).

These sliding doors (121) can be hingedly connected to a support frame that supports a fixed-side material (110). When the sliding door (121) is opened, it can be hingedly rotated on the outside of the support frame so that it can be arranged in a parallel manner.

The biological pretreatment unit (100) sprays wastewater onto the upper part of the fixed bed filter (110), but the upper part of the fixed bed filter (110) often becomes clogged. In this case, the upper part of the fixed bed filter (110) must be opened, and the user must be able to enter and remove the clogged fixed bed filter (110). However, this problem can be solved through the structure of the sliding door (121). That is, when a problem such as the upper part of the fixed bed filter (110) becoming clogged occurs, the user can easily open the sliding door (121), enter the interior, observe the problem, and solve the problem.

When the sliding door (121) is opened, it can be supported by a support member (122). The support member (122) supports the sliding door (121) on the outside of the support frame when the sliding door (121) is opened.

Meanwhile, the biological pretreatment unit (100) may further include an air supply unit (140) installed at the bottom of the fixed bed filter material to supply air to the fixed bed filter material (110). The air supply unit (140) may be composed of a fan (141) that supplies air and an air pipe. The air pipe is arranged at the bottom of the fixed bed filter material (110) to supply air toward the fixed bed filter material (110).

By configuring the air supply unit (140), an environment in which microorganisms can grow well can be provided even in winter or when the temperature difference between the outside air and the fixed filter medium (110) is small.

If there is little temperature difference between the outside air and the fixed filter (110), the air may not circulate and may stagnate. In this case, air can be supplied through the air supply unit (140) located below the fixed filter (110) to circulate the air inside the fixed filter (110).

Meanwhile, the fixed bed filter (110) may include a temperature measuring unit (150) configured to measure temperature, and may further include a control unit (160) that controls the operation of the air supply unit (140) according to the temperature difference between the measured temperature of the fixed bed filter (110) and the temperature of the outside air. The control unit (160) may operate the fan (141) to force air in if the temperature difference between the fixed bed filter (110) and the outside air is 5 degrees or less.

By measuring the temperature through the temperature measuring unit (150) and comparing it with the outside temperature, the air flow inside the fixed bed filter (110) can be predicted, and the fan (141) can be operated automatically or semi-automatically to smoothly adjust the air flow inside the fixed bed filter (110).

Microorganisms are cultured in the fixed bed filter (110). In addition, a sprinkler (130) for spraying wastewater is placed on the upper part of the fixed bed filter (110) so that wastewater is sprayed onto the fixed bed filter (110).

In the biological pretreatment unit (100) using fixed-bed filter media (110), wastewater is sprayed on microorganisms attached to the filter media to oxidize and purify organic substances. At this time, excessively grown attached microorganisms are naturally detached from the filter media and separated into solid and liquid in a sedimentation tank installed at the rear. Through this wastewater treatment, removal of 80% or less of BOD is possible.

Nitrogen, a pollutant in wastewater, can be removed through the nitrification-denitrification process. Organic nitrogen present in wastewater is converted into ammonia nitrogen ( _NH4 +) and oxidized to nitrate ( _NO3- ) by nitrifying bacteria under aerobic conditions. Nitrate is then reduced to gaseous nitrogen ( _N2 ) by denitrifying microorganisms under anaerobic conditions and can then be discharged into the atmosphere.

Denitrifying microorganisms consume organic matter using the oxygen in nitrate as an electron acceptor, and sometimes inject external carbon sources when organic matter is lacking.

There are physical and chemical removal methods as processes for removing phosphorus from wastewater.

The coagulant supply unit (500) stores a coagulant capable of physically and chemically precipitating phosphorus in wastewater. The coagulant includes all types of chemicals known to be capable of precipitating phosphate in wastewater. Typically, coagulants include aluminum sulfate, ferric sulfate, ferric sulfate, polyaluminum chloride, ferric chloride, ferric chloride, etc. In addition, other metal salts and chemicals such as lime may also be used.

The coagulant supply unit (500) can quantitatively supply chemicals to the receiving unit (300) according to the flow rate and treatment concentration of wastewater by means of a quantitative pump.

Meanwhile, environmental factors and wastewater characteristics occurring during the biological pretreatment process can affect the physicochemical phosphorus removal treatment efficiency. In particular, coagulated and precipitated phosphate can be re-dissolved under certain conditions, and the phosphorus removal treatment efficiency of the entire process can decrease.

Accordingly, in a biological pretreatment process using a fixed-bed filter (110), the re-dissolution of phosphate can be prevented through a pretreatment process that increases the oxygen concentration in wastewater flowing vertically through an air-permeable fixed-bed filter (110). Through this, the conditions requiring high phosphorus removal efficiency can be satisfied.

In addition, depending on the phosphorus removal requirement, the pretreated wastewater in the fixed-bed filter (110) may be directly introduced into the upper part of the vertical-flow type artificial wetland (200), or a phosphorus removal coagulant may be injected into the pretreated wastewater through the fixed-bed filter (110) and then introduced into the upper part of the vertical-flow type artificial wetland (200) where reeds are planted.

Sewage water flowing into the upper part of the vertical flow type artificial wetland (200) undergoes nitrification-denitrification treatment as it passes through a filter bed (230) in which purifying plants (A) such as reeds are planted.

The wastewater that has passed through the biological pretreatment unit (100) returns to the receiving unit (300) and is then supplied to the vertical flow type artificial wetland (200). At this time, the wastewater can be moved from the receiving unit (300) to the vertical flow type artificial wetland (200) through the wastewater supply line connecting the receiving unit (300) and the vertical flow type artificial wetland (200).

A water treatment system using an artificial wetland according to the present invention may further include a secondary vertical flow type artificial wetland (200).

Figure 2 is a schematic diagram showing a water treatment system using an artificial wetland according to another embodiment of the present invention. As shown in Figure 2, wastewater that has passed through a first vertical flow type artificial wetland (200) is supplied to a second vertical flow type artificial wetland (700) through a second wastewater supply line (760), so that an additional nitrification-denitrification treatment process of the wastewater can be performed.

The secondary vertical flow type artificial wetland (200) has the same configuration as the primary vertical flow type artificial wetland (200). It includes a filter bed (730) filled with gravel, sand, etc. in an internal space formed of a bottom and side walls of an impermeable material, a drainage channel (740) formed on the bottom of the filter bed (730) through which wastewater moves, and a wastewater discharge device (750) connected to the drainage channel (740) to discharge wastewater. A discharge port (751) of adjustable height may be formed in the wastewater discharge device (750). Depending on the height of the discharge port (751), the filter bed (730) is divided into a submerged lower region (720) and a non-submerged upper region (710).

Wastewater passing through the discharge port (751) can be recirculated to the receiving unit (300) through the recirculation line (600) or discharged into a natural water system. In the case of discharge into a natural water system, the wastewater can be discharged through a separate discharge line (620).

The second vertical flow type artificial wetland (700) has the same configuration as the first, so it is replaced with a description of the configuration of the first vertical flow type artificial wetland (200).

Through the secondary additional nitrification-denitrification process, nitrogen remaining in wastewater can be additionally removed, and BOD ₅ and TKN removal rates can be significantly improved.

Optionally, if necessary, the present invention may further include a pretreatment filter unit (400). The pretreatment filter unit (400) is connected to the receiving unit (300) to pretreat wastewater. The pretreatment filter unit (400) may include a perforated semi-cylindrical metal sheet of an automatic screening sieve type through which foreign substances are discharged by a screw. Solid wastes filtered by the screening sieve are discharged upward through the screw, but the filtered wastewater may be moved to the receiving unit (300) through a pipe by gravity or a pump.

Figure 3 relates to a wastewater treatment method using an artificial wetland according to one embodiment of the present invention.

A method for treating wastewater using an artificial wetland according to one embodiment of the present invention includes a step of biologically pretreating wastewater using a trickling filter, a physicochemical dephosphate treatment step, and a nitrification-denitrification step using the artificial wetland.

And the step of supplying to the artificial wetland includes a process of recovering sludge containing phosphate and particulate phosphorus precipitates of the stirred wastewater from the upper surface.

The process of recovering sludge from the upper surface is to install a soil sensor (211) in the non-submerged upper area (210) of a vertical flow type artificial wetland (200) to measure at least one of moisture and electrical conductivity, and recover sediment in the non-submerged upper area (210) based on the measured value.

Meanwhile, the step of supplying to an artificial wetland may further include a process of installing a soil sensor (211) in a non-submerged upper area of a vertical flow-type artificial wetland (200) to measure at least one of moisture and electrical conductivity, and performing maintenance of the filter material according to the measured value.

The wastewater treatment process is described in detail below.

First, the wastewater received in the receiving unit (300) is transferred to a biological pretreatment process using a pump. The transferred wastewater can have organic matter removed through a biological pretreatment step. The biological pretreatment step is to remove soluble organic matter by spraying the wastewater on top of a fixed bed filter (110) through the action of microorganisms (bacteria, etc.).

The fixed bed filter (110) is a facility for cultivating fixed bed microorganisms in the wastewater to be treated. The fixed bed filter (110) is composed of aligned linings in the form of multi-channel tubes or corrugated cardboard and has a large surface area capable of attaching a high concentration of microorganisms due to the cross-flow method.

The wastewater to be treated is sprayed onto the biological film formed on the fixed bed filter (110) with a large surface area. A spray device (130) is placed on the upper part of the fixed bed filter (110).

FIG. 4 is a drawing showing a sprinkler (130) according to one embodiment of the present invention. The sprinkler (130) sprays wastewater onto the upper portion of a fixed filter medium (110) while a rotating bar (132) including a series of nozzles (133) rotates around a rotating shaft (131). The rotating bar (132) can rotate 360 degrees around the rotating shaft (131).

By rotating the rotary bar (132) 360 degrees, wastewater can be evenly distributed over the entire upper surface of the fixed filter medium (110).

In addition, the rotating bar (132) can spray wastewater toward the fixed filter medium (110) at the bottom or toward the cover part (120) at the top by rotating itself according to the pressure of the supplied wastewater. That is, when the pressure of the supplied wastewater is high, the nozzle (133) rotates upward to spray wastewater toward the bottom of the cover part (120), and when the pressure of the wastewater is low, wastewater can be sprayed toward the top of the fixed filter medium (110) located at the bottom. In this way, the supply direction of the wastewater can be determined by controlling the pressure of the supplied wastewater.

Microorganisms in the biofilm consume some of the biodegradable organic matter and are fixed to the filter medium through microbial metabolism and synthesis. When the biofilm thickens, it can be detached from the fixed-bed filter medium (110) and discharged. Then, the wastewater that has passed through the fixed-bed filter medium (110) and has been biologically pretreated can be transported to the receiving unit (300) through a pipe.

The wastewater that has passed through the biological pretreatment process and has been transferred to the receiving unit (300) undergoes a physicochemical dephosphate treatment step. The physicochemical dephosphate treatment of the wastewater can generally be implemented by injecting a coagulant capable of precipitating phosphate into the wastewater or purified sludge before the biological nitrification-denitrification treatment.

After injecting the coagulant, the wastewater can be stirred so that the coagulant can be evenly dispersed and mixed in the wastewater.

Meanwhile, in the receiving unit (300), wastewater that has passed through the pretreatment filter unit (400) and wastewater that has passed through the biological pretreatment process may be mixed. The water level of the receiving unit (300) may be adjusted according to the amount of wastewater flowing in from the pretreatment filter unit (400) and the treatment conditions of the vertical flow type artificial wetland (200) for nitrification-denitrification treatment.

The wastewater that has gone through the biological pretreatment process can be transported to a vertical flow artificial wetland (200) for nitrification-denitrification treatment. At this time, the step of supplying to the artificial wetland can supply sludge containing phosphate and particulate phosphorus precipitates of the stirred wastewater to the upper surface of the vertical flow artificial wetland (200). At this time, the wastewater in the receiving unit (300) can be moved to the upper surface of the vertical flow artificial wetland (200) by natural flow or a pump.

Sludge containing coagulated precipitated phosphorus and particulate phosphorus can be moved to the surface of a vertical flow type artificial wetland (200) planted with reeds, etc., and removed when dredging the surface of the artificial wetland.

At this time, the vertical flow type artificial wetland (200) may include a filter bed (230) filled with gravel, sand, etc. in an internal space composed of a bottom and side walls of an impermeable material, a drainage channel (240) formed on the bottom of the filter bed (230) through which wastewater moves, and a wastewater discharge device (250) connected to the drainage channel (240) to discharge wastewater.

The wastewater can be sprayed or sprinkled on the upper surface of the filter bed (230) on which purifying plants (A) such as reeds are planted. Spraying or sprinklering is performed by a fixed or mobile spraying/spraying device installed on the upper surface of the filter bed (230). The spray nozzle (133) installed on the upper surface of the filter bed (230) may have limited use when the plants grow luxuriantly.

At this time, wastewater can be supplied to the filter bed (230) by the submersion method. The supply by the submersion method can be introduced through the supply orifices arranged in an alternating manner in the filter bed (230) where reeds, etc. are planted. The supply orifices can be in the form of vertical pipes that extend above the upper surface of the filter bed (230) where reeds are planted. In order to prevent the formation of a groove around the supply orifice, gravel can be piled around it for preparation.

A filter bed (230) planted with aquatic plants (A) such as reeds can be installed through a process of excavation and backfilling. The bottom and side walls of the filter bed (230) can be installed with a geomembrane interposed between a protective geotextile and an impermeable material, thereby preventing untreated wastewater from infiltrating around the filter bed (230) or underground, thereby contaminating the ground environment and groundwater.

The filter bed (230) is filled with filler from the bottom to the top. The particle size of the filler in each layer of the filter bed (230) may be different, and the particle size may decrease from the bottom to the top.

For example, the lower layer may be composed of pebbles with a diameter of 20 to 60 mm and a depth of at least 10 cm, the middle gravel layer may be composed of pebbles with a diameter of 10 to 20 mm and a depth of at least 20 cm, the middle filter layer may be composed of pebbles with a diameter of 4 to 10 mm and a depth of at least 20 cm, and the upper layer may be composed of a mixture of gravels with a diameter of 2 to 5 mm and sand and a depth of at least 30 cm.

Wastewater seeps from the top to the bottom through a filter bed (230) planted with reeds, etc., by gravity. The permeated wastewater moves to a drain (240) at the bottom of the filter bed (230) and is then collected in a wastewater discharge device (250).

At this time, the filter bed (230) can be divided into a non-submerged upper zone (210) and a submerged lower zone (220), and the depth of the submerged lower zone (220) and the depth of the non-submerged upper zone (210) can be controlled by a wastewater discharge device.

The wastewater discharge device (250) may be located inside or outside the filter bed (230). The wastewater discharge device (250) includes a discharge port (251). The height of the discharge port (251) is located between the bottom and the upper surface layer of the filter bed (230). Therefore, the wastewater passing through the filter bed (230) fills the inside of the filter bed (230) until it reaches the height of the discharge port (251). Ultimately, the boundary between the flooded area and the non-flooded area is determined according to the height of the discharge port (251).

According to the present invention, the discharge port (251) is formed as an overflow type and is formed so that the height can be adjusted, thereby also controlling the boundary between the submerged area and the non-submerged area.

In the non-submerged upper zone (210), as the roots and stems of aquatic plants (A) such as reeds grow, oxygen transfer and wastewater infiltration can be promoted. Oxygen is supplied to the filler material through the leaf and stem system of the reeds, and a path is created through which air can freely permeate between the roots of the growing reeds and the gaps between the filler material. In addition, as the roots and stems of the reeds grow, the clogging phenomenon of the surface of the filter bed (230) caused by suspended matter in the wastewater flowing in from the receiving unit (300) is prevented, thereby enabling the wastewater to continuously infiltrate downwards.

Therefore, the upper, non-submerged area is maintained under aerobic conditions. The organic carbon source of the wastewater flowing into the surface of the filter bed (230) helps form an aerobic microbial community that fixes nitrogen. Therefore, the nitrogen-fixing microorganisms formed on the surface of the filter bed (230) convert ammonia nitrogen into nitrate nitrogen and allow the organic carbon source to move to the submerged lower area (220). This submerged lower area (220) is under anoxic conditions, and denitrifying microorganisms denitrify nitrate nitrogen using the remaining organic carbon source.

It is advantageous for the denitrification reaction to be greater in height of the submerged lower zone (220) than in height of the non-submerged upper zone (210). In the present invention, the height of the submerged lower zone (220) may be formed to be about 1.5 to 4 times greater than in height of the non-submerged upper zone (210). Through this configuration, the contact time for the denitrification reaction in the submerged lower zone (220) increases, and the supply of the organic carbon source required for denitrification can proceed smoothly. This height adjustment can be performed by adjusting the height of the discharge port (251) as described above.

After completing the nitrification-denitrification treatment, the wastewater discharged by the wastewater discharge device (250) can be discharged into a natural water system or recirculated to a receiving unit (300) by a recirculation line (600). The treated wastewater can be discharged into a natural water system or moved to a receiving unit (300) by natural flow or a pump. The recirculation rate of the wastewater can be adjusted from 0 to 200%.

FIG. 5 is a plan view of a vertical flow type artificial wetland (200) according to one embodiment of the present invention, FIG. 6 is a cross-sectional view taken along line I-I of FIG. 5, and FIG. 7 is a cross-sectional view taken along line II-II of FIG. 5.

As shown in FIGS. 5 to 7, the water treatment system according to the present invention further includes a tree or shrub (B) together with a water purifying plant (A) on top of a vertical flow type artificial wetland (200).

Trees or shrubs (B) have deeper roots than water-purifying plants (A), so denitrifying microorganisms can be secured at depths of 60 cm or more. This can be confirmed through the depth of roots of trees or shrubs (B) in Fig. 6 and water-purifying plants (A) in Fig. 7. In this way, by planting trees or shrubs (B) in a portion of the upper part of the filter bed (230), denitrifying microorganisms can be secured at a deeper level and in greater numbers, thereby improving the denitrifying effect.

At this time, the tree or shrub (B) can be placed facing north. That is, the tree or shrub (B) can be planted to the north of the filter bed (230), and the water purifying plant (A) can be planted in other areas. Since the tree or shrub (B) grows taller than the water purifying plant (A), if the tree or shrub (B) is planted to the south or another direction instead of the north, the sun may be blocked by the grown tree or shrub (B), which may affect the growth of the water purifying plant (A).

Therefore, trees or shrubs (B) can be planted together with water plants (A), but placed facing north to minimize the adverse effects on the growth of water plants (A).

Meanwhile, a water level sensor is installed in the receiving unit (300) to determine whether sufficient supply of wastewater is possible for each cell in the nitrification-denitrification stage, and then operation can be performed. Using this water level sensor, the operation of the quantitative pump and the coagulation stirring device of the coagulant supply unit (500) can also be controlled.

Figure 8 is a drawing showing a direct path (800) for injection of carbon for denitrification in a submerged area.

As illustrated in FIG. 8, a water treatment system using an artificial wetland according to one embodiment of the present invention may further include a direct path (800) extending from the top to the bottom for injecting a carbon source for denitrification into a submerged lower area (220).

The direct path (800) is formed by a pair of partition structures along the length of the filter bed (230), and extends from the top to the bottom. When wastewater is supplied to the direct path (800), a carbon source for denitrification is supplied into the submerged lower section (220) and then spreads to other sections.

The direct path (800) may include a pair of partition structures extending along the longitudinal direction and a permeation media (810) filling the interior of the pair of partition structures. The permeation media (810) is formed of large gravel of a certain size or larger to enable wastewater to quickly permeate into the lower region.

By directly injecting a carbon source for denitrification into the submerged area in this way, the carbon source insufficient in the lower area of the filter bed (230) can be supplemented.

Meanwhile, the present invention can directly supplement organic matter for denitrification by arranging wood chips under the filter bed (230). Furthermore, phosphorus removal efficiency can be further improved by additionally arranging phosphorus adsorption media such as slag, oyster shells, clay media, and zeolite under the filter bed (230).

In addition, the filter bed (230) may further include a carbon mineralization filter at the bottom. If a mineral, such as wollastonite, is supplied at the bottom of the filter bed (230), the carbon sequestration and storage capacity may be increased. This is possible by inducing a downward flow of CO ₂ generated after decomposition of organic matter within the filter bed (230), so that the dissolved Ca ²⁺ and the HCO ³⁺ released during decomposition of organic matter combine to enable storage in the form of CaCO ₃ (S).

And the present invention may further include a measurement sensor (252) that can be installed in an immersion type inside a wastewater discharge device (250). The measurement sensor (252) can measure at least one or a combination of a plurality of TN, NH ₄ ⁺ , NO ₃ ^- , TP, and PO4-P in the wastewater. In addition, DO, pH, ORP, etc. in the wastewater can be additionally measured and utilized as auxiliary indicators for system operation.

By measuring TN, TP, etc. in the wastewater, the wastewater treatment water quality of the entire artificial wetland can be checked.

Meanwhile, the TP value of the wastewater treatment target can be set, and the amount of coagulant injected into the receiving unit (300) can be controlled according to the measured value of PO4-P. At this time, the flow rate of the receiving unit can be considered as well. The control unit (900) can control the amount of coagulant injected into the receiving unit (300) by controlling the coagulant supply unit (500) according to the measured PO4-P value.

In addition, if the _NH4 ⁺ value of the wastewater in the wastewater discharge device (250) is low and ^the _NO3- value is high, it is judged that nitrification has occurred but the residence time or carbon source required for denitrification is insufficient, and thus the height of the discharge port (751) can be increased to simultaneously increase the submerged area of the entire vertical artificial wetland. As the submerged area increases, denitrification of the wastewater can be induced.

At this time, the height of the discharge port (251) is controlled by the control unit (900) according to the measured value.

On the other hand, if the _NH4 ⁺ value of the wastewater in the wastewater discharge device (250) is high and ^the _NO3- value is low, it is determined that the nitrification process has not progressed sufficiently, and accordingly, the recirculation flow rate through the recirculation line (600) can be adjusted. Depending on the measured _NH4 ⁺ and _NO3- ^values , the control unit controls the circulation control pump (610) formed in the recirculation line (600) to adjust the recirculation flow rate.

If the flow rate of wastewater recycled to the receiving unit (300) is increased, the amount of wastewater fed into the vertical flow type artificial wetland (200) can increase, and accordingly, the residence time of the wastewater in the vertical flow type artificial wetland (200) can be increased and the pollutant removal rate can be increased, thereby inducing nitrification of the wastewater.

Figure 9 is a drawing showing a wastewater treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area according to the present invention.

As illustrated in FIG. 9, the method for treating wastewater using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area according to the present invention includes a step of supplying wastewater to the entire upper portion of the artificial wetland for a certain period of time, a step of stopping the supply of wastewater, a step of supplying wastewater through a direct path again for a certain period of time, and a step of stopping the supply of wastewater, and the above-described process is performed repeatedly.

That is, wastewater is supplied to the entire upper part of a vertical flow-type artificial wetland for a certain period of time, then stopped, and then wastewater is supplied again through a direct route during the stopped period, then stopped, and then wastewater is supplied to the entire upper part again, repeating this process.

Through this process, by directly injecting a carbon source for denitrification into the submerged area, the carbon source that is insufficient in the lower area of the filter bed is forcibly supplied, thereby improving the denitrification efficiency in the lower area of the filter bed.

The scope of protection of the present invention is not limited to the description and expression of the embodiments explicitly described above. In addition, it is added once again that the scope of protection of the present invention may not be limited due to obvious changes or substitutions in the technical field to which the present invention belongs.

100: Biological pretreatment unit
110: Fixed-phase
120: Cover part
121: Sliding door
122: Support
130: sprinkler system
131: Rotation axis
132: Rotating bar
133: Nozzle
140: Air supply section
141: Fan
150: Temperature measuring unit
160: Control Unit
200: Vertical flow artificial wetland
210: Non-submerged upper area
211: Soil Sensor
220: Submerged lower area
230: Filter bed
240: Drain
250: Wastewater discharge device
251: exhaust port
252: Measurement sensor
260: Wastewater supply line
300: Reception area
310: Pump 1
320: 2nd pump
400: Preprocessing filter section
500: Coagulant supply section
600: Recirculation line
610: Circulation control pump
620: Discharge line
700: Secondary vertical flow artificial wetland
710: Non-submerged upper area
720: Submerged lower area
730: Filter bed
740: Drain
750 Wastewater Discharge Device
751: exhaust port
A: Purifying plant
B: Tree or shrub
C: Compartment board
800: Direct route
810: Penetrating media
900: Control Unit

Claims (23)

It includes a vertical flow type artificial wetland consisting of a non-submerged upper area and a submerged lower area, and water purification plants are planted for nitrification-denitrification treatment of wastewater.
The above vertical flow type artificial wetland is,
It further includes a direct path extending from the top to the bottom for injecting a carbon source for denitrification into the submerged lower zone,
The above vertical flow type artificial wetland is,
A filter bed filled with gravel, sand, etc., with an internal space consisting of a bottom and side walls made of impermeable material;
A drain formed at the bottom of the filter bed through which wastewater moves; and
It includes a wastewater discharge device that is connected to the above drain and discharges wastewater,
The above vertical flow type artificial wetland is,
It further includes a discharge port formed between the bottom of the filter bed and the top of the filter bed and capable of dividing the filter bed into a submerged area and a non-submerged area by controlling the water level of the wastewater moved from the wastewater discharge device.
The above discharge port is formed as an overflow type,
The above discharge port is height adjustable,
The above filter bed,
characterized in that it further includes wood chips that can be placed at the bottom to supplement organic matter for denitrification.
A water treatment system using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
delete delete delete In the first paragraph,
The above direct path is,
It further comprises a pair of partition structures extending along the longitudinal direction and a penetrating media filling the interior of the pair of partition structures,
The above-mentioned penetrating media is,
Characterized by being composed of gravel of a certain size or larger,
A water treatment system using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
delete In the first paragraph,
The above filter bed,
characterized in that it is disposed at the bottom and includes at least one filter medium among slag, oyster shell, clay filter medium, and zeolite capable of absorbing phosphorus.
A water treatment system using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
The first step is biological pretreatment of wastewater by using a water filter; and
In order to treat nitrification-denitrification of wastewater that has gone through the above biological pretreatment step, a second step is included in which water purification plants are planted and water is supplied to the upper part of a vertical flow-type artificial wetland consisting of a non-submerged upper section and a submerged lower section for a certain period of time.
The second step above is,
The above-mentioned wastewater is repeatedly supplied and stopped for a certain period of time to the upper part of the above-mentioned vertical flow type artificial wetland, and in the case of the stoppage of the second stage, the step of supplying the wastewater through a direct path extending from the upper part to the lower part for the purpose of injecting a carbon source for denitrification into the submerged lower part for a certain period of time is further included.
The above vertical flow type artificial wetland is,
A filter bed filled with gravel, sand, etc., with an internal space consisting of a bottom and side walls made of impermeable material;
A drain formed at the bottom of the filter bed through which wastewater moves; and
It includes a wastewater discharge device that is connected to the above drain and discharges wastewater,
The above vertical flow type artificial wetland is,
It further includes a discharge port formed between the bottom of the filter bed and the top of the filter bed and capable of dividing the filter bed into a submerged area and a non-submerged area by controlling the water level of the wastewater moved from the wastewater discharge device.
The above discharge port is formed as an overflow type,
The above discharge port is height adjustable,
The above filter bed,
characterized in that it further includes wood chips that can be placed at the bottom to supplement organic matter for denitrification.
A water treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
In Article 8,
The above direct path is,
It further comprises a pair of partition structures extending along the longitudinal direction and a penetrating media filling the interior of the pair of partition structures,
The above-mentioned penetrating media is,
Characterized by being composed of gravel of a certain size or larger,
A water treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
delete In Article 8,
The above filter bed,
characterized in that it is disposed at the bottom and includes at least one filter medium among slag, oyster shell, clay filter medium, and zeolite capable of absorbing phosphorus.
A water treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
In Article 8,
Further comprising a receiving section for receiving wastewater,
The above-mentioned receiving portion is connected to the vertical flow type artificial wetland, and the wastewater of the receiving portion can be transported to the vertical flow type artificial wetland, characterized in that.
A water treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
In Article 12,
characterized in that it further includes a biological pretreatment unit connected to the receiving unit and through which wastewater from the receiving unit can be transferred and biologically pretreated.
A water treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
In Article 12,
A second supply line connecting the above-mentioned receiving portion and the above-mentioned vertical flow type artificial wetland; and
It is characterized by further including a second pump for transporting the wastewater of the above-mentioned receiving portion to the above-mentioned vertical flow type artificial wetland.
A water treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
In Article 13,
A first supply line connecting the above-mentioned receiving unit and the above-mentioned biological pretreatment unit;
characterized in that it further includes a first pump for transporting the wastewater of the above-mentioned receiving section to the above-mentioned biological pretreatment section.
A water treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
In Article 13,
The above biological pretreatment unit is,
A fixed filter medium through which wastewater is sprayed;
Characterized in that it includes a sprinkler device for spraying wastewater onto the fixed filter medium.
A water treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
In Article 16,
The above biological pretreatment unit is,
It is characterized in that it further includes an air supply unit installed at the bottom of the fixed bed filter and supplying air to the fixed bed filter.
A water treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
In Article 17,
In the above fixed media,
Characterized in that it includes a configuration of a temperature measuring unit for measuring the temperature of the above-mentioned fixed phase filter.
A water treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
In Article 18,
It is characterized by further including a control unit that controls the operation of the air supply unit according to the temperature difference between the fixed-phase filter and the outside air.
A water treatment method using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
It includes a first-order vertical flow type artificial wetland and a second-order vertical flow type artificial wetland, which are composed of a non-submerged upper zone and a submerged lower zone, and in which water purification plants are planted for nitrification-denitrification treatment of wastewater.
The wastewater that has passed through the first vertical flow type artificial wetland is supplied to the second vertical flow type artificial wetland.
Each of the above first-order vertical flow type artificial wetlands and second-order vertical flow type artificial wetlands,
It further includes a direct path extending from the top to the bottom for injecting a carbon source for denitrification into the submerged lower zone,
Each of the above first-order vertical flow type artificial wetlands and second-order vertical flow type artificial wetlands,
A filter bed filled with gravel, sand, etc., with an internal space consisting of a bottom and side walls made of impermeable material;
A drain formed at the bottom of the filter bed through which wastewater moves; and
It includes a wastewater discharge device that is connected to the above drain and discharges wastewater,
Each of the above first-order vertical flow type artificial wetlands and second-order vertical flow type artificial wetlands,
It further includes a discharge port formed between the bottom of the filter bed and the top of the filter bed and capable of dividing the filter bed into a submerged area and a non-submerged area by controlling the water level of the wastewater moved from the wastewater discharge device.
The above discharge port is formed as an overflow type,
The above discharge port is height adjustable,
The above filter bed,
characterized in that it further includes wood chips that can be placed at the bottom to supplement organic matter for denitrification.
A water treatment system using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
In Article 20,
The above direct path is,
It further comprises a pair of partition structures extending along the longitudinal direction and a penetrating media filling the interior of the pair of partition structures,
The above-mentioned penetrating media is,
Characterized by being composed of gravel of a certain size or larger,
A water treatment system using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.
delete In Article 20,
The above filter bed,
characterized in that it is disposed at the bottom and includes at least one filter medium among slag, oyster shell, clay filter medium, and zeolite capable of absorbing phosphorus.
A water treatment system using an artificial wetland capable of injecting a carbon source for denitrification into a flooded area.

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