KR100540516B1 - Method and apparatus for treating of dredging sediment - Google Patents

Abstract

The present invention relates to a treatment apparatus for dredged sediment and a method for treating dredged sediment using such an apparatus, wherein the components contained in the dredged sediment are separated by particle size and specific gravity, and the aggregate component having a large particle and specific gravity is transferred to the outside. A hydrocyclone apparatus for evacuating and transporting the particulate and low specific gravity soil components to a subsequent treatment facility; A flocculant is added to the particles transported from the hydrocyclone and a small specific gravity soil component, and the soil component precipitated by the flocculation reaction and the pollutant contained in the soil component are discharged to the outside, and the supernatant is transported to a subsequent treatment facility. Flocculation and sedimentation tank to be used; And pressurized water is added to the supernatant liquid transported from the flocculation / sedimentation tank, and the suspended solids are returned to the tube to which the supernatant liquid is transported from the flocculation / sedimentation tank or the flocculation / sedimentation tank for reprocessing. Provides a treatment device for dredged sediment, including a flotation for discharge to the outside, and a method for treating dredged sediment to separate the recyclable aggregate and soil components contained in the dredged sediment using such a device.

Dredged sediment, hydrocyclone, flocculation and sedimentation tank, flotation tank, flocculant

Description

METHOD AND APPARATUS FOR TREATING OF DREDGING SEDIMENT}             

1 is a view showing an apparatus for treating dredged sediment according to the present invention.

<Explanation of symbols for the main parts of the drawings>

101: sample tank 102: stirring device

103: inverter 104: rotary centrifugal pump

105, 114: pressure gauge 106: hydrocyclone

107: hydrocyclone bottom outlet

108: flocculation and sedimentation tank 109: flocculation and sedimentation tank lower outlet

110: pressurization device 111: reactor

112: flotation 113: flotation lower outlet

115: compressor 116: valve

The present invention provides a device for properly treating dredged sediments generated in large quantities when dredging sediment deposited on the bottom of rivers and lakes, and separating the recyclable aggregate and soil components contained in dredged sediment using such a device. Pulling out relates to a method of treating dredged sediments.

Rivers and lakes used as major water sources in Korea are gradually increasing in water pollution levels, and the amount of sediment is continuously increasing due to the outflow of soil due to rainfall. These sediments act as a major cause of deterioration of the water quality along with the flooding caused by the decrease of the lake's water supply and the deterioration of the river's water capacity. In Korea, from the 1760's, such rivers were prevented from flooding, flood control, river maintenance, collection of construction aggregates, dam water maintenance, and waterway or route dredging were started. Has continued to work primarily on civil engineering. However, since most of the dams and rivers in Korea contain problems due to sediment, in the long term, efforts related to civil works are limited, and effective treatment methods for dredged sediments collected through direct dredging projects are required. .

Conventionally, dredged sediments containing aggregate and soil components are mechanically and physically treated to take only aggregate components, such as sand and gravel, which can be recycled as construction materials, and soil components containing a large amount of pollutants are landfilled or marine Dredging sediments have been treated by means of dumping. Specifically, centrifugal dehydrator (Korean Patent Publication No. 01-107844), hydrocyclone (Korean Patent Publication No. 03-5769), or dissolved air flotation (DAF) (Korean Patent Publication) No. 03-46013) is used to separate only particles having a particle size of 0.83 mm or more and heavy specific gravity, such as sand and gravel contained in dredged sediment, and the particle size and specific gravity of silt, clay, etc. Small materials have simply been dehydrated and landfilled or dumped at sea. In general, however, since pollutants in sediments are strongly adsorbed by silt and clay of several micrometers (μm) in size rather than large particles such as sand, the method of treating them with landfill and ocean dumping reduces the life of landfills. And the risk of causing secondary pollution of land and sea. Therefore, there is a need for development of stabilization treatment of contaminants on dredged sediment, proper separation of effective resources, and recycling of such effective resources.

It is an object of the present invention to provide an apparatus for properly treating the recyclable components contained in dredged sediments.

Another object of the present invention, by using the above mechanical device to separate the aggregate components such as sand and gravel contained in the dredged sediment, as well as chemically stabilized to recycle the soil components containing the remaining large amount of contaminated components It is to provide a method of treating dredged sediment to be treated and separated.

In the present invention, as a result of intensive studies to achieve the above technical problem, after taking the recyclable aggregate component by separating the dredged sediment first according to the size and specific gravity of the particles, the soil component containing contaminated components is chemically treated. The present invention has been completed in view of the fact that a reclaimed earth and sand component can be obtained by coagulation and sedimentation, and a reclaimable soil and sand component can be further obtained by treatment with pressurized water.

The present invention, by putting the dredged sediment in a hydrocyclone to separate the components contained in the dredged sediment by particle size and specific gravity, the aggregate component having a large particle and specific gravity is discharged to the outside, Transporting to a flocculation tank; A coagulant is added to the particles transported from the hydrocyclone and a small specific gravity soil component, and the soil component precipitated by the flocculation reaction and the soil component contained in the soil component are discharged to the outside, and the supernatant is transported to the flotation tank. ; And pressurized water is added to the residual soil component contained in the supernatant liquid transported from the flocculation / sedimentation tank, and the suspended solids are returned to the flocculation / sedimentation tank for reprocessing, and the suspended solids are discharged to the outside. It relates to a method for treating dredged sediment, comprising a.

According to the treatment method of the dredged sediment of the present invention, before the dredged sediment is added to the hydrocyclone, the method may further comprise the step of uniformly mixing the dredged sediment in the sample tank with a stirring device, the flocculation sedimentation tank At least one of the inorganic electrolyte group consisting of aluminum sulfate, calcium hydroxide (calcinized lime), aluminum chloride, iron (II) sulfate and iron (II) chloride is used as a flocculant to be transported from the hydrocyclone and the small-soil soil component. Can be selected and used. In addition, in order to properly treat the dredged sediment according to the present invention, it is preferable to first set the pressure conditions inside the hydrocyclone to 1.5kg / ㎠ to separate the components contained in the dredged sediment by particle size and specific gravity In addition, it is preferable to add aluminum sulfate at a concentration of 40 mg / L as a flocculant to the particles transported from the hydrocyclone to the flocculation and sedimentation tank and the small specific gravity soil component, and to the supernatant liquid transported from the flocculation and precipitation tank to the flotation tank. Pressurized water is preferably introduced at a rate of 30% relative to the total amount present in the flotation bath.

In addition, the present invention is to separate the components contained in the dredged sediment by particle size and specific gravity, to discharge the particles and aggregate components having a large specific gravity to the outside, and to transport the sediment component having a small particle and specific gravity to a subsequent treatment facility Clones (hydrocyclone); A flocculant is added to the particles transported from the hydrocyclone and a small specific gravity soil component, and the soil component precipitated by the flocculation reaction and the pollutant contained in the soil component are discharged to the outside, and the supernatant is transported to a subsequent treatment facility. Flocculation and sedimentation tank to be used; And pressurized water is added to the residual soil component contained in the supernatant liquid transported from the flocculation and sedimentation tank, and the suspended solids are returned to the flocculation and sedimentation tank for reprocessing, and the suspended solids are discharged to the outside. It relates to a treatment apparatus for dredged sediment, comprising a floating tank.

In the apparatus for treating dredged sediments according to the present invention, a sample tank having a stirring device may be further provided before the hydrocyclone to uniformly mix the dredged sediments. In order to properly separate the dredged deposits uniformly mixed in the sample tank in the hydrocyclone, the hydrocyclone is an inverter for controlling the flow rate of the dredged sediment introduced into the hydrocyclone, and a pressure source for supplying pressure. It is preferred to include a rotary centrifugal pump as a pressure gauge and a pressure gauge for regulating the pressure of the dredged deposits entering the hydrocyclone. In addition, the floating tank includes a pressurizing device for applying pressure to the water and a reaction tank for applying the pressurized pressurized water to the supernatant liquid transported from the flocculation and sedimentation tank, wherein the pressurizing device controls the pressure applied to the water. It is preferred to include a pressure gauge for the compressor and a compressor for supplying air to the water.

Hereinafter, with reference to the drawings showing an embodiment of the present invention will be described in more detail with respect to the apparatus for treating dredged sediment according to the present invention, and the method for treating dredged sediment using the same. The following drawings and description do not limit the invention, and the invention may be appropriately modified and modified based on the details set forth in the claims.

1 illustrates an apparatus for treating components contained in dredged sediment in accordance with the present invention. First, when dredging deposits collected through dredging operations in rivers and lakes are introduced into the sample tank 101, the dredging deposits are uniformly mixed by the stirring device 102 inside the sample tank 101. The mixed dredged deposit is then transported to a hydrocyclone 106 connected with the sample tank 101. At this time, the amount of dredged sediment introduced into the hydrocyclone 106 is controlled by the inverter 103, the dredged sediment is continuously introduced into the hydrocyclone 106 by receiving the pressure energy by the rotary centrifugal pump 104. The pressure supplied by the rotary centrifugal pump 104 is appropriately controlled by the pressure gauge 105. As such, the dredged sediment introduced into the hydrocyclone under appropriate pressure is separated into the upper sample having a smaller particle and specific gravity and the lower sample having a higher specific gravity, depending on the size and specific gravity of the particles under the influence of centrifugal acceleration. The lower sample containing aggregate components such as sand and gravel is discharged to the outside through the hydrocyclone lower outlet 107, and is recycled after being washed and dehydrated, and includes soil components such as silt and clay containing a large amount of contaminants. The collected upper sample is transported to the flocculation and sedimentation tank 108 for subsequent processing. The preferred degree of pressure applied to the dredged sediment for proper separation of the lower sample and the upper sample in the hydrocyclone 106 will be described in more detail in Experimental Example 1 below.

The particles transported from the hydrocyclone 106 to the flocculation and sedimentation tank 108 and the sample having a small specific gravity are selected from the group consisting of aluminum sulfate, calcium hydroxide (calcite), aluminum chloride, iron sulfate (II) and iron chloride (II). It is treated with a flocculant which is at least one inorganic electrolyte. The appropriate amount of flocculant introduced at this time will be described in more detail in Experimental Example 2 below. By the coagulant treatment, the earth and sand contained in the sample and the contaminants adsorbed thereon are stabilized and granulated to settle to the bottom of the flocculation / sedimentation tank 108. The sedimentary components, which are precipitated and concentrated in this way, are discharged to the outside through the condensation / sedimentation tank lower outlet 109 and properly evaluated according to a conventional method according to environmental emission standards, and then the contamination is extremely low. Silver is recycled through a series of post-treatment processes, such as washing, dehydration and drying, and some components not suitable for recycling are disposed of by landfill. On the other hand, in the supernatant that did not settle after the treatment with the flocculant, not only the non-aggregated soil component and suspended solids remain, but also the pollutant adsorbed thereto and the pollutant component eluted from the soil during the granulation process. As it is contained, the supernatant is transported to flotation tank 112 to finally separate recyclable components from these components.

The floatation tank 112 which uses pressurized water to separate only the earth and sand components from the earth and sand components, suspended matter, contaminants, etc. contained in the supernatant, is pressurized device 110 and pressurized water for producing the pressurized water. It consists of a reaction tank 111 to apply to the object to be processed, the pressurizing device 110 is composed of a pressure gauge 114, a pressure regulating device and a compressor 115, which is a device for supplying air to the water. The pressurized water introduced into the reaction tank 111 from the pressurizing device 110 of the floating tank 112 releases supersaturated air by being exposed to the atmospheric pressure state of the reaction tank 111, which serves to attach and float to a material having a small specific gravity. do. According to this principle, when the pressurized water is introduced into the reaction tank 111, components having a small specific gravity, such as suspended solids and contaminants present in the supernatant, are floated in a state of being attached to supersaturated air, whereby the specific gravity is large and precipitated. The component separated from the earth and sand component existing in the state, and having a small specific gravity present in the floating state in this way, is conveyed to the agglomeration / sedimentation tank 108 for reprocessing. The conveying place for the reprocessing can be appropriately selected according to the amount of the component having a small specific gravity present in the floating state, and the material to be reprocessed can be introduced into the selected conveying place by adjusting the valve 116. . An appropriate amount of pressurized water to the reaction tank 111 will be described in more detail in Experimental Example 3 below. On the other hand, the earth and sand components precipitated at the bottom of the reaction tank 111 is discharged to the outside through the floating tank bottom outlet 113 is recycled or disposed in the same manner as the earth and sand components obtained in the flocculation, sedimentation tank 108.

An experimental example is given below to present the optimum operating conditions of the treatment apparatus for dredged sediment according to the present invention.

Experimental Example 1

Optimal Pressure Conditions of Hydrocyclone for Separation of Dredged Sediments

Hydrocyclone according to the pressure conditions by applying the pressure of 0.5, 1.0 and 1.5 ㎏ / ㎠ to the samples of 2.5, 5.0 and 7.5% (W / V) of the solid content in the sample, respectively The particle separation efficiency of the clones was tested. Table 1 shows the separation efficiency for the upper sample of the hydrocyclone and Table 2 shows the separation efficiency for the lower sample.

As shown in Table 1 and Table 2, the upper sample and the lower sample of the hydrocyclone showed better separation efficiency according to the large pressure regardless of the solid content, and the maximum at a pressure of 1.5 kg / cm 2. Separation efficiency is shown. On the other hand, when a pressure exceeding 1.5 kg / cm 2 is applied, the lower sample under a large pressure is driven to the lower portion of the hydrocyclone at once, so that a blocking phenomenon occurs and the separation efficiency of the lower sample drops rapidly. Indicated. Considering not only the blocking phenomenon but also the economic utility such as the operating cost of the hydrocyclone, it can be seen that the optimum pressure condition for separating the samples by particles in the hydrocyclone according to the results of Experimental Example 1 is 1.5㎏ / ㎠. .

Experimental Example 2

Optimum amount of flocculant and flocculation reaction time for flocculation reaction of soil components

In six test tubes prepared in advance, a sample having a solids content of 3% (W / V) was put into each test tube using aluminum sulfate (Al ₂ (SO ₄ ) _{3 18} H ₂ O) as a flocculant. 40, 80, 160 and 320 mg / l. In the same manner as above, the same experiment was carried out on the samples with 4 and 5% solids (W / V), and the suspended solids removal efficiency of the supernatant after the flocculation / precipitation reaction was observed. The results are shown in Table 3 below.

As shown in Table 3, the sample having a solid content of 3% (W / V) showed the best suspended solids removal efficiency when the flocculant was added at a concentration of 80 mg / l, and the solid content was 4 and 5% (W). / V) showed the best suspended solids removal efficiency when a coagulant was added at a concentration of 40 mg / L. According to the results of Experimental Example 2, it can be seen that the amount of economically effective aluminum sulfate for flocculation and sedimentation of the earth and sand components is 40 mg / L.

On the other hand, when 40 mg / L of aluminum sulfate was added to the sample, an arbitrary sample was placed in a test tube of 90 cm in order to measure the time required for the coagulation / precipitation reaction by observing the time of transition from local precipitation to compression precipitation. 40 mg / L of aluminum sulfate was added thereto, and the precipitation pattern was visually observed. The change in height of the precipitate over time is shown in Table 4 below.

From the data shown in Table 4, it can be seen that the precipitation rate is 0.42 ± 0.1 m / min when an appropriate amount of flocculant is added. In addition, by visual observation, almost all of the precipitate precipitated between 105 and 120 seconds, the supernatant was remarkably clear, and the precipitate was continuously compressed to a height of about 5 cm. From these results, it can be seen that the time point from the local precipitation to the compression precipitation is 105 to 120 seconds, and the aggregation reaction time required when aluminum sulfate is used at a concentration of 40 mg / L as the flocculant is about 120 seconds.

Experimental Example 3

Pressurized water input for optimum flotation efficiency in flotation tank

After completion of the flocculation / precipitation reaction in Experimental Example 2, any of the supernatants containing the suspended solids at a concentration of 97.4 mg per liter were divided into three equal parts, and each of them was added to three reactors, and the pressurization produced by the pressurization apparatus was added thereto. Water was added respectively. At this time, the amount of pressurized water to be added, based on the total amount present in the flotation tank so that the pressurized water occupies the ratio of 20, 30 and 40%, respectively. While the pressurized water was added, the concentration change of the suspended solid according to the ratio of pressurized water was observed, and the results are shown in Table 5 below.

As shown in Table 5, the inside of the reaction tank was separated into the floating region and the non-injured region by the addition of pressurized water, and the change in the concentration of suspended solids in the floating region and the non-injured region was different depending on the ratio of pressurized water. That is, when the pressurized water was introduced at a rate of 20% relative to the total amount present in the flotation tank, the concentration of suspended solids (64.7 mg / L) in the flotation zone was the concentration of suspended solids (97.4 mg) in the supernatant. / l) and do not show a significant difference from the suspended solids concentration (64.4 mg / l) in the non-injured area, while the proportion of 30% or 40% of the total amount of pressurized water present in the flotation In this case, the concentration of suspended solids (316.7 mg / l and 256.7 mg / l, respectively) in the floating zone was significantly increased, while the values of suspended solids (29.0 mg / l and 36.5 mg, respectively) in the non-injured zone were significantly increased. / l) was measured. In particular, when pressurized water was introduced at a rate of 30% relative to the total amount present in the flotation tank, the concentration of the best suspended solids in the flotation region and the non-injury region, respectively, was shown.

On the other hand, pressurized water at any ratio (20%, 30%, 40%) to any supernatant, in order to observe the effect of the input ratio of the pressurized water on the floating rate of the suspended matter when the pressurized water is added to the supernatant Were administered three times each to measure the rate of injury and averaged. The results are shown in Table 6 below.

The data in Table 6 show that the input rate of pressurized water has little effect on the flotation speed of suspended solids. Therefore, when combining the results of Table 5 and Table 6, it can be seen that the preferred input ratio of the pressurized water is 30% of the total amount of the pressurized water and the supernatant.

According to the apparatus for treating dredged sediment according to the present invention and a method for treating dredged sediment using the optimum operating conditions thereof, the aggregate component contained in the dredged sediment can be obtained and recycled as construction materials, as well as contaminants. By treating the earth and sand component containing a large amount stably and obtaining it to the maximum, it can be recycled as a raw material, such as a cover material or ceramics. This is not only an economical method in terms of recycling waste resources, but it is also an environmentally friendly method because of the low pollution and extremely low amounts of some dredged sediments that can be disposed of by landfill or marine emissions.

Claims (14)

Dredged sediment is put into hydrocyclone and the components contained in the dredged sediment are separated by particle size and specific gravity, so that the particles and aggregates with large specific gravity are discharged to the outside, and the soil and small specific gravity sediment are separated into coagulation and sedimentation tanks. Transporting; A flocculant is added to the particles transported from the hydrocyclone to the flocculation and sedimentation tank and a small specific gravity soil component, and the soil component precipitated by the flocculation reaction and the soil component contained in the soil component are discharged to the outside. Transporting to the flotation tank; And Injecting pressurized water into the supernatant liquid transported from the flocculation / sedimentation tank to the flotation tank, returning the suspended matter to the flocculation / sedimentation tank for reprocessing, and discharging the material that is not suspended and precipitated to the outside; Method of treating dredged sediment, comprising a. The method of claim 1, And prior to introducing the dredged sediment into the hydrocyclone, uniformly mixing the dredged sediment in a sample tank equipped with a stirring device. Way. The method of claim 1, In the flocculation and sedimentation tank, the flocculant added to the particles transported from the hydrocyclone and the small specific gravity soil component is at least one selected from the group consisting of aluminum sulfate, calcium hydroxide (calcite), aluminum chloride, iron sulfate (II) and iron chloride (II). It is one kind of inorganic electrolyte, Way. The method of claim 1, Pressure conditions inside the hydrocyclone to separate the components contained in the dredged sediment by particle size and specific gravity is characterized in that 1.5kg / ㎠ Way. The method of claim 1, 40 mg / L of aluminum sulfate is added as a flocculant to the particle | grains conveyed by the said flocculation and sedimentation tank, and a small specific gravity earth and sand component. Way. The method of claim 1, Characterized in that the pressurized water to the supernatant transported to the flotation tank at a rate of 30% of the total amount present in the flotation tank Way. A hydrocyclone to separate the components contained in the dredged sediment by particle size and specific gravity, to discharge the particles and the aggregate specific gravity component to the outside, and to transport the particulate and small specific gravity soil components to a subsequent treatment facility; A flocculant is added to the particles transported from the hydrocyclone and a small specific gravity soil component, and the soil component precipitated by the flocculation reaction and the pollutant contained in the soil component are discharged to the outside, and the supernatant is transported to a subsequent treatment facility. Flocculation and sedimentation tank to be used; And Pressurized water is introduced into the supernatant liquid transported from the flocculation / sedimentation tank, and the suspended solids are returned to the flocculation / sedimentation tank for reprocessing, and the flotation material without flotation includes a flotation tank for discharging to the outside. The hydrocyclone is, An inverter for regulating the flow rate of dredged sediment introduced into the hydrocyclone; A rotary centrifugal pump as a pressure source for supplying pressure; And A pressure gauge for regulating the pressure of the dredged sediment entering the hydrocyclone, The flotation tank, A pressurization device for applying pressure to the water, the pressurization device comprising a pressure gauge for adjusting the pressure and a compressor for supplying air to the water; And Reaction tank which adds pressurized water to the supernatant liquid conveyed from the said flocculation and sedimentation tank. Dredging sediment treatment device, characterized in that consisting of. The method of claim 7, wherein Before the hydrocyclone, further comprising a sample tank having a stirring device for uniformly mixing the dredged sediment Device. delete delete The method of claim 7, wherein The flocculant is at least one inorganic electrolyte selected from the group consisting of aluminum sulfate, calcium hydroxide (calcite lime), aluminum chloride, iron sulfate (II), iron chloride (II). Device. The method of claim 7, wherein The pressure condition inside the hydrocyclone is characterized in that 1.5kg / ㎠ Device. The method of claim 7, wherein The amount of aluminum sulfate as a flocculant in the flocculation / precipitation tank is 40 mg / L, characterized in that Device. The method of claim 7, wherein Input of pressurized water in the flotation tank is characterized in that the rate of 30% to the total amount present in the flotation tank Device.

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