JP6274978B2 - Muddy water treatment system and muddy water treatment method - Google Patents

Description

  The present invention relates to a muddy water treatment system and a muddy water treatment method.

  Turbid water generated at a civil engineering construction site or the like is treated so that the pH and SS (suspended substance) concentration are within the environmental standard values. For example, Patent Document 1 describes a system including a raw water tank that stores raw water and a solid-liquid separation device that separates raw water added with a flocculant into sludge and separated water. In the system described in Patent Document 1, turbid water generated at a civil engineering work site is used as raw water, and when the raw water is detected as high alkali, a flocculant is added to a line that is transferred to a solid-liquid separation device to perform solid-liquid separation. To do.

JP 2002-205075 A

  By the way, when classifying cleaning is performed to treat disaster waste generated by an earthquake disaster or tsunami deposits generated by a tsunami disaster, the post-cleaning water generated by this classifying cleaning is turbid water containing a large amount of inorganic and organic substances. It becomes. Moreover, since the pollution state of disaster waste and tsunami deposits varies widely, the nature of muddy water varies greatly with time. Therefore, it is difficult for the conventional treatment system to stably treat turbid water whose properties vary greatly.

  An object of the present invention is to provide a turbid water treatment system and a turbid water treatment method capable of stably treating turbid water generated with cleaning of disaster waste, tsunami deposits, and the like.

  The turbid water treatment system according to the present invention is provided with a first agglomeration reaction tank and a first precipitation tank for introducing turbid water and agglomerating and precipitating, and introducing water to be treated from the first precipitation tank. A turbid water treatment system comprising a second agglomeration reaction tank and a second precipitation tank for agglomeration and sedimentation treatment, wherein an alkaline substance is added so that the first treated water in the first agglomeration reaction tank becomes alkaline. An alkali addition means, an acid addition means for adding an acidic substance so that the second treated water in the second agglomeration reaction tank becomes acidic, and a first for adding the first flocculant to the first treated water A flocculant addition means; a second flocculant addition means for adding the second flocculant to the second treated water; a turbidity / SS detection means for detecting turbidity or SS concentration of turbid water; First flocculant based on turbidity or SS concentration detected by SS detecting means A flocculant control means for controlling the addition amount, characterized in that it comprises a.

  The turbid water treatment method according to the present invention includes a first agglomeration reaction tank and a first precipitation tank for introducing turbid water and aggregating and precipitating the treated water from the first precipitation tank. A muddy water treatment method using a muddy water treatment system including a second agglomeration reaction tank and a second precipitation tank that are introduced and agglomerated and settled, wherein the first treated water in the first agglomeration reaction tank becomes alkaline. Thus, an alkali addition step of adding an alkaline substance, an acid addition step of adding an acidic substance so that the second treated water in the second agglomeration reaction tank becomes acidic, and a first flocculant in the first treated water A first flocculant addition step and a second flocculant addition step to add the second flocculant to the second treated water. In the first flocculant addition step, the turbidity or SS concentration of turbid water is adjusted. Based on this, the amount of the first flocculant added is controlled.

  According to such a muddy water treatment system and muddy water treatment method, two-stage coagulation sedimentation treatment is performed. The first treated water in the first flocculation reaction tank is adjusted to be alkaline and subjected to flocculation and precipitation treatment. Subsequently, the second treated water in the second flocculation reaction tank is adjusted to be acidic and subjected to flocculation and precipitation treatment. In the first stage coagulation sedimentation process, mainly heavy metals and SS are reduced, and in the second stage coagulation sedimentation process, organic substances such as COD are mainly reduced. The present inventors have found that it is effective to use the turbidity or SS concentration of turbid water as an index when treating turbid water with large property fluctuations that occurs due to cleaning of disaster waste or tsunami deposits. It was. The amount of the first flocculant added is controlled based on the turbidity or SS concentration of muddy water by the flocculant control means (flocculating agent control step). Thereby, even when the properties of turbid water fluctuate, the first-stage coagulation sedimentation process is performed satisfactorily. Moreover, the influence which the fluctuation | variation of the property of turbid water has on the second stage coagulation sedimentation processing can be reduced. As a result, it is possible to stably treat turbid water generated in response to cleaning of disaster waste, tsunami deposits, and the like.

  In the present invention, the first flocculation reaction tank and the second flocculation reaction tank are provided with pH detection means for detecting the pH of the first treated water and the pH of the second treated water, respectively. Based on the pH detected by the means, the alkali addition means is controlled so that the first treated water in the first agglomeration reaction tank becomes alkaline, and the second treated water in the second agglomeration reaction tank becomes acidic. A pH control means for controlling the acid addition means may be provided. With this configuration, it is possible to reliably adjust the first treated water to be alkaline and the second treated water to be acidic.

  Further, the flocculant control means may control the amount of the second flocculant added based on the turbidity or SS concentration detected by the turbidity / SS detection means. With this configuration, the amount of the second flocculant added is adjusted in accordance with fluctuations in the properties of muddy water. Therefore, turbid water generated by cleaning disaster waste, tsunami deposits, etc. can be treated more stably.

  The first flocculant and / or the second flocculant may include a polymer flocculant. In this case, flocs formed by the aggregation reaction are likely to grow greatly. Therefore, the effect of solid-liquid separation performed in the first precipitation tank and / or the second precipitation tank is further exhibited.

  Further, the first flocculant and the second flocculant may be different flocculants. In this case, since the range of types of inorganic and organic substances that can be handled is widened, stable treatment can be performed even if fluctuations in the properties of turbid water increase.

  ADVANTAGE OF THE INVENTION According to this invention, the muddy water which arises with washing | cleaning of a disaster waste, a tsunami deposit, etc. can be processed stably.

It is a flowchart which shows the outline | summary of the recycling method of mixed waste. It is a flowchart which shows a crushing and sorting process. It is a flowchart which shows a soil washing | cleaning process. It is a flowchart which shows the outline | summary of the recycling method of a tsunami deposit. It is a flowchart which shows the muddy water processing system which concerns on one Embodiment of this invention.

  Embodiments according to the present invention will be specifically described below with reference to the drawings. For convenience, the same reference numerals are given to the same elements in the description of the drawings, and duplicate descriptions are omitted. The present invention is widely applicable to turbid water having a large variation in properties that occurs when various wastes are washed. Here, as an example, a turbid water treatment system and a turbid water treatment method for turbid water generated by processing such as classification cleaning in the case of performing recycling processing on waste generated by a tsunami disaster will be described.

  Wastes in tsunami disasters can be broadly classified into disaster wastes and tsunami deposits. In the present embodiment, disaster waste is further classified into concrete waste, wood waste and mixed waste. Moreover, tsunami deposits are classified into tsunami deposits that contain harmful substances above the standard and tsunami deposits that do not contain harmful substances above the standard. Since both the mixed waste and the tsunami deposit originate from a tsunami disaster, they contain earth and sand that are rolled up from the seabed. When the mixed waste and tsunami deposits are recycled, muddy water is generated due to classification cleaning and the like. The turbid water treatment system of the present embodiment performs a coagulation sedimentation treatment on such turbid water. Hereinafter, the recycling process regarding mixed waste and tsunami deposits, and the muddy water treatment system and muddy water treatment method of the present embodiment will be described.

  Mixed waste is combustible (wood scrap, waste plastic, paper, cloth, etc.), non-combustible (earth and sand, stone, concrete glass, glass, ceramic scrap, metal, etc.), hazardous materials (asbestos-containing materials, PBC, etc.) Waste, gas cylinders, fire extinguishers, etc.), memorable items (photos, albums, items, items with special meaning for individuals such as valuables), etc., and tsunami-derived sediment It is in the state.

  As shown in FIG. 1, the mixed waste recycling system 1 includes a crushing and sorting step S100, a soil washing step S200, and an incineration step S300. The crushing and sorting step S100 is a step in which waste that is directly recycled and fine particles and combustibles that require further steps to become recycled are sorted by the crushing and sorting means. The soil washing step S200 is a washing step S200a for washing fine particles by a washing means and separating attached viscous soil and the like, and a muddy water treatment step S200b for treating muddy water A (see FIG. 3) generated by the washing step S200, Is included. The incineration step S300 is a step in which the combustible material selected in the crushing and sorting step S100 and the like is incinerated by a combustible material incineration means and processed into a recycled material. Hereinafter, each step will be described in detail.

  FIG. 2 is a flowchart showing details of the crushing and sorting step S100. As shown in FIG. 2, the crushing and sorting step S100 is a waste in which wastes of different sizes are mixed with a step of crushing wastes of a predetermined size or more (coarse crushing step S102, crushing step S107). A process of classifying the group into a plurality of classes according to size (classification process S103, S108) and a process of sorting combustibles, non-combustibles, metals, etc. from the waste (rough sorting process S101, manual sorting process S104, magnetic sorting process S105) , S106, S111, wind sorting process S109, rotating rod sorting process S110).

  In the crushing and sorting step S100, first, the mixed waste is sent to the rough sorting step S101. In this rough sorting step S101, wood waste that can be used as fuel and raw materials, metal scrap that can be used as scrap, concrete glass and stone that can be used as recycled crushed stone, and waste plastic that can be used as fuel can be recycled from the mixed waste. Removed as material. Further, in the rough sorting step S101, dangerous goods and memories that are not suitable for recycling are also removed.

  The waste material including the long material that has undergone the coarse sorting step S101 is roughly pulverized to about 300 mm or less in the coarse crushing step S102. In the rough crushing step S102, for example, a crusher as a crushing means such as a biaxial shear crusher is used. The roughly crushed waste is classified into those larger than 100 mm, those of 30 mm to 100 mm, and those of 30 mm or less by the classification step S103. In this classification step S103, for example, a vibrating sieve is used as a classification means.

  For those larger than 100 mm, non-ferrous metal, concrete glass / stone, tile / brick, and glass / ceramics are sorted by the manual sorting step S104. Non-ferrous metals, concrete glass and stone are recycled materials that can be used as scrap. Tile, brick, glass and ceramics are recycled materials that can be used as civil engineering materials. The waste from which such recycled materials are removed is subsequently sent to the magnetic force sorting step S105. By this magnetic force sorting step S105, iron scrap is sorted as an available recycling material. The thing from which the iron scrap has been removed by the magnetic sorting process S105 is sent to the incineration process S300 as a combustible material.

  What was classified into 30 mm-100 mm by classification | category process S103 is sorted as a recycle material which can use iron scrap as a scrap by magnetic selection process S106. The waste from which the iron scrap has been removed is crushed by a crusher such as a Hanmark crusher in the crushing step S107. Those after crushing are classified into those having a size of 30 mm or less and those having a size larger than 30 mm by the classification step S108 using a vibration sieve. And the thing of 30 mm or less is sorted as a fine grain thing, and is sent to soil washing process S200.

  The waste classified as larger than 30 mm by the classification step S108 is sent to the wind sorting step S109. In the wind sorting process S109, combustibles are sorted by sorting using a wind sorting device as wind sorting means. The selected combustible material is sent to the incineration step S300.

  Many of the things collected in the incombustible material collection unit in the wind sorting step S109 are incombustible materials, but include combustible materials that could not be completely sorted by the wind power sorter. Therefore, by further fine sorting by a rotary rod sorting device as a rotary rod sorting means, a part is sorted as combustible material and sent to the incineration step S300. The remaining waste (incombustible material) is collected as recycled materials that can be used as civil engineering materials.

  The waste classified as 30 mm or less by the classification step S103 is sorted as fine particles (under the sieve) after the iron scrap is removed by magnetic sorting. Iron scrap is recycled as scrap. The fine particles sorted by the crushing and sorting step S100 are sent to the soil washing step S200.

  In the soil washing step S200, gravel / sand that can be used as a civil engineering material and solidified material (dehydrated sludge) that can also be used as a civil engineering material are selected from the fine particles as recycled materials. FIG. 3 is a flowchart showing details of the soil washing step S200. As shown in FIG. 3, the soil washing step S200 includes a washing step S200a for washing fine particles and separating the attached viscous soil and the like, and coagulation precipitation treatment and insolubilization for the turbid water A generated by the washing step S200a. -It has muddy water treatment process S200b which performs a dehydration solidification process. The sewage generated by the cleaning step S200a becomes turbid water A.

  The fine-grained material is a mixed waste of 30 mm or less. For example, viscous soil (silt, clay) is attached to a mixture of incombustible material such as gravel, sand, and iron scrap and combustible material. The fine particles contain harmful substances such as arsenic, boron and fluorine. These harmful substances tend to adhere to viscous soil having a smaller particle size than gravel and sand.

  In the cleaning step S200a, first, combustible materials are sorted by a buoyancy sorting step S201 using a buoyancy sorting device as a buoyancy sorting means. By the buoyancy sorting step S201, the combustible material is removed from the fine particles.

  Subsequently, the fine particles from which the combustible material has been removed are sent to the magnetic force sorting step S202. In the magnetic sorting process S202, iron scraps are sorted from the fine particles. The fine granule from which the iron scrap has been removed is sent to the defatting cleaning step S203. In the sludge cleaning step S203, the viscous soil attached to the fine particles is unraveled by a drum scrubber or the like, so that the viscous soil is removed (sorted) from the fine particles as sewage. In addition, in FIG. 3, the flow of sewage is shown by the broken line.

  The fine particles from which the cohesive soil has been removed are sent to the classification step S204. In the classification step S204, the material is classified into one having a size of 10 mm or more, one having a size greater than 2 mm and less than 10 mm, and a size having a size of 2 mm or less. The thing of 10 mm or more is divided into a combustible material and an incombustible material by buoyancy sorting process S205 using a buoyancy sorter. Incombustibles are sorted as recyclable gravel as civil engineering materials. Similarly, those larger than 2 mm and smaller than 10 mm are classified into combustible materials and non-combustible materials by the buoyancy sorting step S206 using the buoyancy sorting device. Incombustibles are sorted as recyclable gravel as civil engineering materials. Those having a size of 2 mm or less are further classified into those larger than 0.074 mm and sewage containing 0.074 mm or less by the classification step S207 using a high mesh separator. Those larger than 0.074 mm are washed by a rice scrubbing step S208 using a log washer and sorted as recyclable sand as a civil engineering material. The sewage containing 0.074 mm or less, and the sewage generated in the defatting cleaning step S203, the classification step S204, and the fouling washing step S208 are converted into turbid water A and sent to the turbid water treatment step S200b.

  The muddy water treatment step S200b includes a coagulation sedimentation treatment step S210 for performing the coagulation sedimentation treatment, and an insolubilization / dehydration solidification treatment S211 for performing the insolubilization / dehydration solidification treatment on the sludge generated in the coagulation sedimentation treatment step S210. This muddy water treatment step S200b will be described later.

Next, the processing method of a tsunami deposit is demonstrated. The tsunami deposit is subjected to a soil analysis for every predetermined amount (for example, about 900 m ³ ) to determine whether or not harmful substances exceeding the reference value are contained in the sediment. The reference value is defined by, for example, the Soil Contamination Countermeasures Law. As a result of soil analysis, those exceeding the reference value are classified as tsunami deposits (contaminated), and those not exceeding the reference value are classified as tsunami deposits (no contamination). The tsunami deposit (contaminated) and the tsunami deposit (contaminated) are recycled by different systems.

  The tsunami deposit (contaminated) recycling system 4 will be described with reference to FIG. Most of the tsunami deposit (contaminated) is composed of earth and sand, but also includes waste other than earth and sand. Therefore, among the tsunami deposits (contaminated), those having a size of 100 mm or less are selected by the classification step S401 using a vibrating sieve. Tsunami deposits (contaminated) larger than 100 mm are sent as waste to the crushing and sorting step S100 in the mixed waste processing step.

  Tsunami deposits (contaminated) of 100 mm or less are sent to the magnetic separation step S402, and iron scrap that can be recycled as scrap is removed. The tsunami deposit from which the iron scrap has been removed (contaminated) is sent to the defatting cleaning step S403. In the demolition cleaning step S403, the viscous soil attached to the tsunami deposit (contaminated) is unraveled by a drum scrubber or the like, so that the viscous soil is removed (sorted) as sewage from the tsunami deposit (contaminated). . In addition, in FIG. 4, the flow of sewage is shown with the broken line.

  The tsunami deposit from which the cohesive soil has been removed (contaminated) is sent to the classification step S404. In the classification step S404, the material is classified into those having a size of 40 mm or more, those having a size greater than 2 mm and less than 40 mm, and those having a size of 2 mm or less by using trommel. A thing of 40 mm or more is sent to the recycling system 1 of mixed waste as mixed waste. Those larger than 2 mm and smaller than 40 mm are classified into combustible materials and non-combustible materials by the buoyancy sorting step S405 using the buoyancy sorting device. The combustible material is sent to the incineration step S300. Incombustibles are sorted as recyclable gravel as civil engineering materials. Those having a diameter of 2 mm or less are washed by a rice scrubbing step S406 using a log washer and sent to a classification step S407. In the classification step S407, those having a size of 2 mm or less are classified into those having a size larger than 0.074 mm and sewage containing those having a size of 0.074 mm or less by the washing classifier, and further washing is performed. Those larger than 0.074 mm are selected as sand that can be recycled as civil engineering materials. The sewage containing 0.074 mm or less, and the sewage generated in the defatting cleaning step S403 and the classification step S404 become turbid water B and are sent to the turbid water treatment step S400. The muddy water treatment step S400 includes a coagulation sedimentation treatment step S410 for performing the coagulation sedimentation treatment, and an insolubilization / dehydration solidification treatment step S411 for performing insolubilization / dehydration solidification treatment on the sludge generated in the coagulation sedimentation treatment step S410.

  Hereinafter, the turbid water treatment step S200b and the turbid water treatment step S400, in which the turbid water A and the turbid water B are subjected to coagulation sedimentation treatment and insolubilization / dehydration solidification treatment, will be described. The muddy water treatment step S200b and the muddy water treatment step S400 are performed using the muddy water treatment system 200, respectively.

  As shown in FIG. 5, the muddy water treatment system 200 includes a raw water tank 201 that introduces muddy water A or muddy water B, and a first coagulation reaction tank 202 that performs first-stage coagulation sedimentation treatment on muddy water A or muddy water B. And a first settling tank 203, and a second settling reaction tank 205 and a second settling tank 206 that perform the second settling settling process. A first pH adjustment tank 204 is provided between the first precipitation tank 203 and the second agglomeration reaction tank 205. A second pH adjustment tank 207 and a water storage tank 208 are provided downstream of the second sedimentation tank 206.

  The muddy water treatment system 200 further includes an acid addition unit 213, an alkali addition unit 214, an inorganic flocculant addition unit 211, a polymer flocculant addition unit 212, and an insolubilization / dehydration solidification unit 240. Hereinafter, the treated water that flows out from the raw water tank 201 and flows into the first agglomeration reaction tank 202 and the treated water in the first agglomeration reaction tank 202 are referred to as first treated water and flows out from the first sedimentation tank 203. The treated water flowing into the second agglomeration reaction tank 205 and the treated water in the second agglomeration reaction tank 205 are referred to as second treated water.

  The first flocculation reaction tank 202 introduces the first treated water that has flowed out of the raw water tank 201 and performs the flocculation reaction. An inorganic flocculant addition unit 211 and a polymer flocculant addition unit 212 for adding the first flocculant are connected to the first agglomeration reaction tank 202. Here, the inorganic flocculant adding means 211 and the polymer flocculant adding means 212 and the line where they are connected to the first aggregating reaction tank 202 are the first flocculant adding means for adding the first flocculant. It corresponds to. A first flocculant is added to the first flocculant reaction tank 202 by the first flocculant adding means. The first agglomeration reaction tank 202 is connected with an alkali addition means 214 for adding an alkaline substance. The first treated water in the first agglomeration reaction tank 202 is adjusted to be alkaline by adding an alkaline substance by the alkali adding means 214. Therefore, the coagulation reaction between the first coagulant and the first treated water in the first coagulation reaction tank 202 is performed under alkaline conditions.

  The first coagulant is added to the first coagulation reaction tank 202 by the first coagulant adding means. The first flocculant forms flocs by growing and reacting with the first treated water in an alkaline environment. As the first flocculant, for example, an inorganic flocculant, a polymer flocculant, or a combination of an inorganic flocculant and a polymer flocculant is used. Examples of the inorganic flocculant include sulfuric acid band, aluminum chloride, PAC (polyaluminum chloride), ferric chloride, polyferric sulfate and the like. Examples of the polymer flocculant include an anionic flocculant, a nonionic flocculant, and a cationic flocculant. The first flocculant includes an inorganic flocculant. Since the first flocculant reacts with the first treated water in an alkaline environment, heavy metals, SS, and the like are likely to be reduced in the first-stage coagulation precipitation treatment. The first flocculant preferably contains a polymer flocculant. In this case, the flocs formed by the aggregation reaction of the inorganic flocculant are likely to be greatly grown by the polymer flocculant. When the floc formed by the agglomeration reaction becomes large, the effect of the solid-liquid separation performed in the next first precipitation tank 203 is further exhibited.

  The alkali adding means 214 adds an alkaline substance to the first treated water in order to adjust the first treated water in the first flocculating reaction tank 202 to a pH value suitable for the flocculating reaction with the first flocculating agent. . Examples of the alkaline substance include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and calcium hydroxide.

  The 1st sedimentation tank 203 introduces the liquid mixture of the 1st to-be-processed water and the 1st flocculant from the 1st aggregation reaction tank 202, and carries out solid-liquid separation into separation water and sludge. The separated water at the top of the first sedimentation tank 203 flows into the first pH adjustment tank 204. The first pH adjustment tank 204 is connected with an acid addition means 213 for adding an acidic substance. The acid addition means 213 adds an acidic substance to the second treated water in order to adjust the second treated water in the first pH adjusting tank 204 to a pH value suitable for the second stage aggregation reaction. Examples of the acidic substance include inorganic acids, organic acids, and acidic inorganic acid salts. The acid addition means 213 may be configured to be connected to the second aggregation reaction tank 205 and add an acidic substance to the second treated water in the second aggregation reaction tank 205. The sludge in the lower part of the first sedimentation tank 203 is sent to the insolubilization / dehydration solidification means 240 by a sludge pump.

  The second agglomeration reaction tank 205 performs agglomeration reaction by introducing the second treated water that has flowed out of the second pH adjustment tank 207. An inorganic flocculant adding means 211 and a polymer flocculant adding means 212 for adding the second flocculant are connected to the second aggregating reaction tank 205. Here, the inorganic flocculant adding means 211 and the polymer flocculant adding means 212 and the line where they are connected to the second aggregating reaction tank 205 are the second flocculant adding means for adding the second flocculant. It corresponds to. The second flocculant is added to the second flocculant reaction tank 205 by the second flocculant adding means.

  The second flocculant is capable of performing the aggregation reaction in an acidic environment. The second flocculant forms flocs by growing and aggregating with the second treated water in an acidic environment. As the second flocculant, the same (that is, the same) flocculant as the first flocculant described above may be used.

  The 2nd sedimentation tank 206 introduces the liquid mixture of the 2nd to-be-processed water and the 2nd flocculant from the 2nd aggregation reaction tank 205, and carries out solid-liquid separation into separation water and sludge. The separated water in the upper part of the second sedimentation tank 206 flows into the second pH adjustment tank 207. The sludge below the second settling tank 206 is sent to the insolubilization / dehydration solidification means 240 by a sludge pump.

  An acid addition unit 213 and an alkali addition unit 214 are connected to the second pH adjustment tank 207. The separated water from the second settling tank 206 is adjusted to a neutral pH by the acid addition unit 213 or the alkali addition unit 214. The treated water adjusted to the neutral pH is stored in the water storage tank 208 and used for the mixed waste and tsunami deposit cleaning equipment (circulated and used).

  The insolubilization / dehydration solidification means 240 introduces sludge from the first precipitation tank 203 and the second precipitation tank 206 to perform insolubilization / dehydration solidification processing. An insolubilizing agent is added to the insolubilizing / dehydrating solidifying means 240, and the sludge and the insolubilizing agent are mixed. The sludge mixed with the insolubilizer is dehydrated by a dehydrating device (solidifying means) such as a filter press. Thereby, sludge is isolate | separated into a dewatering cake and a water | moisture content (detachment | desorption liquid). The dehydrated cake is solidified, for example, by adding a gypsum-based solidifying material, and becomes a solidified product. This solidified product can be recycled as a civil engineering material.

  As the insolubilizing agent, for example, iron salt-based, chelate-based, magnesium-based, aluminum salt-based, inorganic mineral-based insolubilizing agents are used, and these include quick lime, dihydrate gypsum, hemihydrate gypsum, magnesium oxide, chloride. Examples include magnesium, magnesium sulfate, aluminum chloride, aluminum sulfate, polyaluminum chloride, ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, and other substances that inhibit harmful substances and heavy metal elution.

  The turbid water treatment system 200 of the present embodiment includes a turbidity / SS detection unit that detects turbidity or SS concentration of turbid water, and a turbid water / SS concentration detected by the turbidity / SS detection unit. Flocculant control means 220 for controlling the amount of flocculant added is further provided.

  The turbidity / SS detection means includes an SS meter 209 provided in the raw water tank 201. The turbidity / SS detection means may include a turbidimeter provided in the raw water tank 201. The turbidity / SS detection means is connected to the flocculant control means 220, and sends the detected information to the flocculant control means 220. The flocculant control means 220 calculates the addition amount of the first flocculant based on the turbidity or SS concentration of the turbid water obtained from the turbidity / SS detection means, and the first flocculant addition means is based on the calculated addition amount. Control. Thus, the flocculant control means 220 controls the addition amount of the 1st flocculant added to the 1st aggregation reaction tank 202 based on the turbidity or SS density | concentration of muddy water.

  The flocculant control means 220 controls the amount of the second flocculant added to the second agglomeration reaction tank 205 based on the turbidity or SS concentration of turbid water. In this case, the flocculant control means 220 calculates the addition amount of the second flocculant based on the information detected by the turbidity / SS detection means, and controls the second flocculant addition means based on the calculated addition amount. . In this way, the flocculant control means 220 can control the addition amount of the first flocculant and the addition amount of the second flocculant based on the turbidity or SS concentration of turbid water. In this case, the amount of the second flocculant added can be adjusted in accordance with fluctuations in the properties of the turbid water. Therefore, even if the effect of the first-stage agglomeration reaction treatment varies due to fluctuations in the properties of turbid water, the second-stage agglomeration reaction process using the second aggregating agent can stably perform the agglomeration-precipitation process. That is, muddy water can be treated more stably.

  The muddy water treatment system 200 includes pH control means 230 that controls the first treated water in the first agglomeration reaction tank 202 to be alkaline. The first agglomeration reaction tank 202 is provided with pH detection means for detecting the pH value. This pH detection means is connected to the pH control means 230 and sends the detected pH value to the pH control means 230. The pH control unit 230 calculates the addition amount of the alkaline substance based on the acquired pH value, and controls the alkali addition unit 214 based on the calculated addition amount. Therefore, the addition amount of the alkaline substance to the first treated water can be controlled. The pH control means 230 can be controlled so that the first treated water in the first agglomeration reaction tank 202 becomes predetermined alkaline. A suitable pH in the first stage agglutination reaction is, for example, about 8 to 11.

  Furthermore, the pH control means 230 controls the acid addition means 213 so that the second treated water in the second agglomeration reaction tank 205 becomes acidic. The first pH adjustment tank 204 is provided with pH detection means for detecting the pH value. This pH detection means is connected to the pH control means 230 and sends the detected pH value to the pH control means 230. The pH control unit 230 calculates the addition amount of the acidic substance based on the acquired pH value, and controls the acid addition unit 213 based on the calculated addition amount. Therefore, the amount of acidic substance added to the second treated water can be controlled. The pH control means 230 can be controlled so that the second treated water in the first pH adjustment tank 204 becomes a predetermined acidity. A suitable pH in the second stage agglutination reaction is, for example, about 4 to 6. A suitable pH value may be appropriately determined by performing a jar test or the like according to the nature of the muddy water.

  By the pH control means 230 described above, the first water to be treated in the first agglomeration reaction tank 202 is adjusted by the alkali addition means 214 so as to be predetermined alkaline. The second treated water in the second agglomeration reaction tank 205 is adjusted by the acid addition means 213 so as to have a predetermined acidity. With this configuration, the first treated water can be reliably adjusted to have a predetermined alkalinity and the second treated water can be adjusted to a predetermined acidity, and the coagulation sedimentation process can be performed stably.

  A muddy water treatment method using the muddy water treatment system 200 described above will be described.

  First, the muddy water A generated by the mixed waste or the muddy water B generated by the tsunami deposit is caused to flow into the raw water tank 201. In the raw water tank 201, turbid water is stirred by a stirrer or the like so as not to have a concentration unevenness, and is introduced into the first agglomeration reaction tank 202.

  An alkaline substance is added to the first treated water in the first agglomeration reaction tank 202 by the alkali adding means 214 to adjust the first treated water to be alkaline (alkali adding step). Further, the first flocculant adding means adds the first flocculant to the first treated water in the first flocculent reaction tank 202 (first flocculant adding step). In the first flocculant addition step, the amount of the first flocculant added is controlled based on the turbidity of turbid water or the SS concentration. In the first flocculation reaction tank 202, the first flocculation reaction is performed under alkaline conditions.

  More specifically, the amount of the first flocculant added in the first flocculant addition step is controlled based on the turbidity or SS concentration of turbid water. First, the turbidity or SS concentration of turbid water is detected by a turbidity / SS concentration detecting means. The turbidity or SS concentration detected by the turbidity / SS concentration detection means is sent to the flocculant control means 220. The flocculant control means 220 calculates the addition amount of the first flocculant based on the acquired turbidity or SS concentration. The flocculant control means 220 controls the first flocculant addition means based on the calculated addition amount of the first flocculant, and controls the addition amount of the first flocculant.

  Then, the 1st to-be-processed water containing the floc formed by the aggregation reaction in the 1st aggregation reaction tank 202 is introduce | transduced into the 1st sedimentation tank 203, and it solid-liquid separates into sludge and separated water. This separated water is sent to the first pH adjustment tank 204 as the second treated water. The acid addition means 213 adds an acidic substance to the second treated water in the first pH adjustment tank 204 to adjust the second treated water to be acidic (acid addition step). The second treated water adjusted to be acidic is sent to the second agglomeration reaction tank 205.

  The second flocculant addition means adds the second flocculant to the second treated water in the second flocculant reaction tank 205 (second flocculant addition step). In the second agglomeration reaction tank 205, the second-stage agglutination reaction is performed under acidic conditions. The second treated water containing flocs formed by the agglomeration reaction is introduced into the second settling tank 206, and is solid-liquid separated into sludge and separated water. This separated water is sent to the second pH adjusting tank 207, adjusted to a neutral pH, and then stored in the water storage tank 208 as treated water. The treated water stored in the water storage tank 208 is circulated and used for cleaning facilities for mixed waste and tsunami deposits.

  In the present embodiment, the turbid water A is generated by the washing step S200a for the mixed waste, and therefore contains fine particles of soil particles of 0.074 mm or less. The turbid water B is produced by the classification cleaning process for tsunami deposits, etc., so it contains fine particles of soil particles of 0.074 mm or less, and harmful substances including heavy metals, arsenic, fluorine, etc. due to the substances involved in the tsunami deposits Is included. Furthermore, the muddy water A and muddy water B contain organic substances such as COD caused by tsunami disasters and nature. In addition, the properties of mixed waste and tsunami deposits vary greatly depending on the location where they are temporarily placed. Therefore, the properties of turbid water generated when the mixed waste and tsunami deposits are recycled vary greatly with time.

  The present inventors have found that it is effective to use the turbidity or SS concentration of turbid water as an index when treating turbid water with large property fluctuations that occurs due to cleaning of disaster waste or tsunami deposits. The present embodiment has been reached.

  That is, according to the turbid water treatment system 200 and the turbid water treatment method of the present embodiment, heavy metals and SS are mainly reduced in the first stage coagulation sedimentation process, and mainly COD etc. in the second stage coagulation sedimentation process. Organic substances are reduced. The amount of the first flocculant added is controlled by the flocculant control means (flocculating agent control step) 220 based on the turbidity or SS concentration of the turbid water. Thereby, even when the properties of turbid water fluctuate, the first-stage coagulation sedimentation process is performed satisfactorily. Moreover, the influence which the fluctuation | variation of the property of turbid water has on the second stage coagulation sedimentation processing can be reduced. As a result, it is possible to stably treat turbid water generated in response to cleaning of disaster waste, tsunami deposits, and the like.

  In addition, an acid addition unit 213 is connected to the first agglomeration reaction tank 202. As a result, even when the turbid water has a highly alkaline pH value, the first treated water in the first agglomeration reaction tank 202 is adjusted to an appropriate alkaline pH value, and The agglutination reaction is suitably performed. An alkali addition unit 214 is connected to the second agglomeration reaction tank 205. Thereby, even if it is a case where the pH value of the 2nd to-be-treated water falls too much by the 1st stage flocculation sedimentation processing, the 2nd to-be-treated water in the 2nd agglomeration reaction tank 205 has an appropriate acidic pH Thus, the agglomeration reaction in the second agglomeration reaction tank 205 is suitably performed.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be made. For example, in the above embodiment, the first flocculant addition means or the second flocculant addition means shares the inorganic flocculant addition means 211 and the polymer flocculant addition means 212, but the single first flocculant addition means You may provide an addition means and a 2nd aggregation addition means, respectively. In this case, since the addition of the first flocculant and the addition of the second flocculant are independent, the addition amount of the first flocculant and the addition amount of the second flocculant can be controlled separately.

  Further, the first flocculant and the second flocculant may be different flocculants. In this case, since the range of types of inorganic substances and organic substances that can be handled is widened, stable coagulation and precipitation treatment can be performed even if fluctuations in the properties of turbid water increase.

  Further, the first flocculant addition means may be connected to a line connecting the raw water tank 201 and the first aggregation reaction tank 202. In this case, the first flocculant is added to the first treated water before flowing into the first flocculation reaction tank 202. With this configuration, the first flocculant and the first water to be treated are sufficiently mixed, so that the aggregation reaction in the first aggregation reaction tank 202 is sufficiently performed. The second flocculant addition means may be connected to a line connecting the first precipitation tank 203 and the second aggregation reaction tank 205 or the first pH adjustment tank 204. In this case, the second flocculant is added to the second treated water before flowing into the second agglomeration reaction tank 205. With this configuration, the second aggregating agent and the second treated water are sufficiently mixed, so that the aggregating reaction in the second aggregating reaction tank 205 is sufficiently performed.

  Further, the first flocculant may be added after the first treated water in the first agglomeration reaction tank 202 is adjusted to an alkaline pH value. At this time, the first flocculant is added after being adjusted to an alkalinity suitable for the flocculant reaction of the first flocculant, so that the flocculent reaction in the first flocculent reaction tank 202 is sufficiently performed. The second flocculant may be added after the second treated water in the second agglomeration reaction tank 205 is adjusted to an acidic pH value. At this time, the second aggregating agent is added after being adjusted to an acidity suitable for the aggregating reaction of the second aggregating agent, so that the aggregating reaction in the second aggregating reaction tank 205 is sufficiently performed.

  In the above embodiment, the case where the addition amount of the first flocculant and the addition amount of the second flocculant is controlled by the flocculant control means 220 has been described. However, the flocculant control means 220 only adds the addition amount of the first flocculant. May be controlled. That is, the amount of the second flocculant added may be constant. In the above embodiment, the case where the alkaline pH value in the first flocculation reaction tank 202 and the acidic pH value in the second flocculation reaction tank 205 are controlled by the pH control means 230 has been described, but the pH control means 230 is omitted. May be.

  DESCRIPTION OF SYMBOLS 200 ... Turbid water treatment system, 202 ... 1st aggregation reaction tank, 203 ... 1st precipitation tank, 204 ... 1st pH adjustment tank, 205 ... 2nd aggregation reaction tank, 206 ... 2nd precipitation tank, 211 ... Inorganic flocculant addition means , 212 ... polymer flocculant addition means, 213 ... acid addition means, 214 ... alkali addition means, 220 ... flocculant control means, 230 ... pH control means, 240 ... insolubilization / dehydration solidification means.

Claims (6)

A first agglomeration reaction tank and a first precipitation tank for introducing turbid water to perform the first stage of agglomeration and precipitation treatment, and a water to be treated from the first precipitation tank, which is provided at the rear stage of the first precipitation tank, are introduced. A turbid water treatment system comprising a second agglomeration reaction tank and a second sedimentation tank for performing a second-stage agglomeration precipitation process,
The turbid water is turbid water generated by cleaning at least one of disaster waste and tsunami deposit, and includes heavy metals, SS, and organic substances,
Alkali adding means for adding an alkaline substance so that the first treated water in the first agglomeration reaction tank is alkaline;
Acid addition means for adding an acidic substance so that the second treated water in the second agglomeration reaction tank is acidic;
First flocculant addition means for adding the first flocculant to the first treated water;
A second flocculant addition means for adding a second flocculant to the second treated water;
Turbidity / SS detection means for detecting the turbidity or SS concentration of the turbid water,
A flocculant control means for controlling the amount of the first flocculant added based on the turbidity or SS concentration detected by the turbidity / SS detection means;
Equipped with a,
In the first-stage coagulation sedimentation treatment in which the alkali addition means and the first coagulant addition means are provided, mainly reduce the heavy metal concentration and the SS concentration,
Turbid water treatment system the acid addition means and the second flocculant means are in coagulation precipitation treatment of the second stage that is provided, it characterized that you reduce mainly organic material. The first aggregation reaction tank and the second aggregation reaction tank are provided with pH detection means for detecting the pH of the first treated water and the pH of the second treated water, respectively.
Based on the pH detected by the pH detection means, the alkali addition means is controlled so that the first treated water in the first agglomeration reaction tank becomes alkaline and the second in the second agglomeration reaction tank. PH control means for controlling the acid addition means so that the water to be treated becomes acidic,
The muddy water treatment system according to claim 1.   The said flocculant control means controls the addition amount of a said 2nd flocculant based on the turbidity or SS density | concentration detected by the said turbidity / SS detection means, Turbid water treatment system.   The muddy water treatment system according to claim 1, wherein the first flocculant and / or the second flocculant includes a polymer flocculant.   The muddy water treatment system according to any one of claims 1 to 4, wherein the first flocculant and the second flocculant are different flocculants. A first agglomeration reaction tank and a first precipitation tank for introducing turbid water to perform the first stage of agglomeration and precipitation; and water to be treated from the first precipitation tank is introduced after the first precipitation tank. A muddy water treatment method using a muddy water treatment system comprising a second agglomeration reaction tank and a second precipitation tank for performing a second-stage agglomeration precipitation process,
The turbid water is turbid water generated by cleaning at least one of disaster waste and tsunami deposit, and includes heavy metals, SS, and organic substances,
An alkali addition step of adding an alkaline substance so that the first treated water in the first agglomeration reaction tank becomes alkaline;
An acid addition step of adding an acidic substance so that the second treated water in the second agglomeration reaction tank is acidic;
A first flocculant addition step of adding a first flocculant to the first treated water;
A second flocculant addition step of adding a second flocculant to the second treated water,
In the first flocculant addition step, the addition amount of the first flocculant is controlled based on the turbidity or SS concentration of the turbid water ,
In the first stage coagulation precipitation process including the alkali addition step and the first coagulant addition step, mainly heavy metal concentration and SS concentration are reduced,
A muddy water treatment method characterized in that organic substances are mainly reduced in the second-stage coagulation-precipitation treatment in which the acid addition step and the second coagulant addition step are provided .

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