JP4557566B2 - Disposal methods for contaminated water, contaminated mud, and other contaminants - Google Patents

Description

  The present invention relates to a method for treating a contaminated object containing harmful substances such as dioxins (hereinafter referred to as DXNs). For example, DXNs generated in a cleaning operation at the time of dismantling of a waste incineration facility, etc. After processing the contaminated water, or adding water to the sediment containing DXNs and heavy metals deposited in harbors and lakes or the soil containing DXNs and heavy metals to form a slurry and classifying and removing coarse particles After that, it is effectively applied to the treatment of contaminated mud containing a large amount of fine particles and DXNs and heavy metals.

With the enforcement of the Special Measures Measures against Dioxins (hereinafter referred to as the “ DXN Measures Special Measures Act ”) , the need for dismantling old (incompatible with new emission standards) waste incineration facilities is increasing. The waste incineration facility is composed of an incinerator main body, a flue facility, a dust removing device, a smoke exhaust cooling facility, a smoke cleaning facility, a wastewater treatment facility, a waste heat boiler, and the like. In these areas, especially inside, harmful substances such as DXNs exist as furnace wall deposits, incineration ash, fly ash, and DXNs are scattered in and around the workplace as these facilities are dismantled. there is a possibility. For this reason, in dismantling of the incineration facility, prior to dismantling, a method of covering and sealing the entire work place, removing furnace wall deposits, incineration ash, and fly ash to prevent diffusion is adopted.

  As a general decontamination method, the inside of the facility is washed with high-pressure jet water, and the incinerator main body, flue equipment, dust removal equipment, etc. are removed by a cleaning nozzle by a worker wearing protective equipment. Do. The inside of the chimney with the difference in elevation can be cleaned by a method in which a special high-pressure injection device is suspended by a crane.

  The past treatment technologies for such cleaning contaminated water are roughly classified into the following two.

  (1) A method in which the generated contaminated water is collected in a tank car in a muddy state and then taken out, and the muddy water is incinerated at a treatment facility that complies with the new emission standards.

  (2) A method of installing intermediate treatment facilities within the incineration facility demolition site. As this processing method, high-level processing such as coagulation sedimentation, sand filtration, membrane separation and adsorption, and chemical processing is generally performed. Basically, solid-liquid separation is performed, the supernatant water is reused as washing water, and the precipitate is dehydrated by a filter press or the like. In this case, soluble DXNs exist in the filtrate, or DXNs are contained in the SS (Suspended Solid) component in the filtrate. Chemical treatment, etc. is performed, and it is discharged below the emission standard (10 pg-TEQ / L). Volume-reduced dehydrated cake is melted or baked at a treatment facility that meets the new emission standards.

  In addition, according to the DXN Countermeasures Special Measures Law, the environmental standard of 150 pg-TEQ / g is set for the DXN content of sediments, and it is required to take prompt measures for harbor sediments exceeding this standard. Countermeasures include excavation and removal of contaminated sediment, sand covering and in-situ solidification. Of these, in excavation and removal treatment, after decontamination and volume reduction of contaminated sediment, detoxification treatment, landfill, insolubilization treatment, etc. are performed according to the DXN content concentration, etc. Selected. The volume reduction of the dredged sediment is generally performed by dewatering with a filter press after removing coarse particles.

  In this case, most of the DXNs and toxic heavy metals are often adsorbed on the mud fine particles, and the DXNs and heavy metals are concentrated in the SS in the filtrate, and soluble DXNs and heavy metals are concentrated. Since it may exist, advanced treatments such as coagulation sedimentation, sand filtration, membrane separation and adsorption, and chemical treatment are required as post-treatment of filtered water.

In addition, as a prior art related to the present invention, the present applicant has applied for a dehydration and solidification method for a highly water-containing slurry (see Patent Document 1). The present invention is a method for efficiently dewatering sparingly dehydrated highly water-containing slurry such as dredged bottom mud and construction sludge, and enabling effective use of dehydrated cake. A specific treatment material A is added to one slurry to prepare A mud slurry, and the other specific treatment material B is added to the other slurry to prepare B mud slurry. This is a so-called mud wrap method in which mud slurry is cast and dehydrated, and then B mud slurry is cast and dehydrated through a precoat layer of A mud cake.
JP 2000-24694 A

  However, the conventional method (1) has a drawback that it requires a large amount of sludge water to be carried out and is expensive to carry out. Although the method (2) is reduced in volume, it is a combination of multiple processing technologies and requires a lot of processing equipment and processes. There is a drawback that the processing cost is high.

  In addition, the current series of treatments of contaminated mud dewatering, dewatering cake insolubilization and drainage purification is a combination of multiple treatment technologies and requires many treatment facilities and processes. There are drawbacks such as complicated maintenance and high processing costs.

  The present invention has been made to solve the above-mentioned problems, and can treat contaminated water and contaminated mud containing harmful substances such as DXNs and heavy metals with relatively simple treatment equipment and treatment steps. Provided is a method for treating a contaminated object that can be performed at a low cost, and can reliably capture and contain harmful substances such as DXNs and heavy metals in a dehydrated cake, and can obtain filtered water below the discharge standard. There is.

Claim 1 of the present invention is a method for treating a pollutant treatment object (contaminated water such as cleaning contaminated water, contaminated mud such as dredged soil, or contaminated soil) containing harmful substances (DXNs, heavy metals, etc.). A mud slurry composed of mud material that captures harmful substances is placed in the dehydration treatment chamber, and B mud slurry composed of contaminated objects containing harmful substances is placed in the A mud slurry. then, a mud layer was dried with B mud slurry as pre-coat layer of dehydrated cake was solid-liquid separation (a mud and B mud) and drainage, it捉 reliably catching harmful substances in the dehydrated cake pollution treatment A method for processing an object,
For the dehydration treatment, a filter press having a plurality of filter chambers arranged in the press direction is used, and air pressure is supplied from the outside to the implantation flow path formed in the press direction formed from the plurality of filter chamber implantation ports. Then, the residual B mud remaining in the inlet is removed first, and then a secondary scraper is formed by passing a scraper having a shape capable of closing the cross section of the inlet passage through the inlet passage, and then fresh water is supplied to the inlet passage. Perform tertiary removal by passing through,
The method for treating a contamination treatment object is characterized in that an auxiliary filter cloth continuous with the filter cloth is provided on the surface of a filter cloth fixing member provided at a driving hole of a filter chamber of the filter press.

  The feature of the present invention is that DXNs are hardly soluble in water, and most of them are derived from SS (suspended suspended solids), and the precoat layer (A mud layer: conventional) that is a feature of the mud wrap method. In contrast to using contaminated water or contaminated mud), the SS content in DXNs and contaminated water and heavy mud containing heavy metals (B mud) is captured in the dehydrated cake. Soluble DXNs are adsorbed by the adsorbent, and the drainage is discharged below the discharge standard. Reduced volume of dehydrated cake will be subjected to appropriate final disposal such as decomposition and detoxification or landfill disposal according to the concentration of contamination at processing facilities that meet the new emission standards.

  In the case of treatment of contaminated water, B mud composed of contaminated water containing harmful substances by placing A mud slurry composed of mud material that captures harmful substances (DXNs, heavy metals, etc.) in the dehydration chamber The slurry is cast into the A mud slurry, and then the B mud slurry is dehydrated using the A mud layer as a precoat layer, and is solid-liquid separated into dewatered cake (A mud and B mud) and filtered water, Ensuring that harmful substances are captured and drainage water below the discharge standard. That is, for example, a technology that installs treatment facilities in the site of demolition of incineration facilities and performs intermediate treatment of contaminated water. Contamination including DXNs generated in cleaning operations or other facilities when dismantling waste incineration facilities Water (B mud slurry) is treated with dewatered B mud slurry using A mud layer made of mud material as filter and adsorption layer, and DXNs are captured and adsorbed in dehydrated cake (A mud and B mud). Can be contained by insolubilization.

  In the case of treatment of contaminated mud such as dredged soil, A mud slurry composed of mud material that captures harmful substances (DXNs, heavy metals, etc.) is placed in the dehydration treatment room, and it is composed of contaminated mud containing harmful substances. The B mud slurry is placed in the A mud slurry, and then the B mud slurry is dehydrated using the A mud layer as a precoat layer, and solid-liquid separated into a dehydrated cake (A mud and B mud) and filtrate, To ensure that harmful substances are trapped in the dewatered cake, and to treat the harmful substances in the filtered water below various emission standards. That is, processing of contaminated mud (B mud slurry) such as DXNs and fine metal-containing slurries containing heavy metals after washing of sediment and contaminated soil, and filter A mud layer made of mud material not containing pollutants B mud slurry is dehydrated as an adsorbing layer, and DXNs and the like are trapped in the dehydrated cake and contained by adsorption, insolubilization, or the like.

  Claim 2 of the present invention is the treatment method according to claim 1, wherein the mud material of the A mud slurry is a water-insoluble solution in which a particle group of 75 μm or more is 10% by mass or less and an average particle size is 20 μm or less. It is a processing method of the contamination processing target object characterized by consisting of a conductive inorganic particle. In the case of treatment of contaminated water, water-insoluble inorganic particles having a particle group of 75 μm or more and 10% by mass or less and an average particle size of 10 μm or less are preferable. In the case of treatment of contaminated mud, the average particle size is set to 20 μm or less to ensure efficient dehydration and cake peelability.

  Claim 3 of the present invention is the treatment method according to claim 2, wherein the water-insoluble inorganic particles are one or more of stone powder (calcium carbonate, silica powder, etc.) or bentonite when the contaminated water is treated. In the case of processing a contaminated mud, it is a mud material made of a mixture of one or more of clay, stone powder, and coal ash. is there. That is, in the case of contaminated water treatment, A mud is a filter and an adsorption layer for capturing DXNs and the like, and therefore, water-insoluble inorganic particles having a particle size suitable for capturing DXNs and the like, for example, Use artificial or externally supplied mud such as stone powder or bentonite. Also in the case of contaminated mud, A mud is a filter and adsorption layer for capturing DXNs and heavy metals, so use water-insoluble inorganic particles suitable for capturing these harmful substances. .

  According to a fourth aspect of the present invention, in the treatment method according to any one of the first to third aspects, the inorganic flocculant (PAC, sulfate band, slaked lime, In the case of treatment of contaminated mud, inorganic flocculants and / or organic flocculants (such as polysulfate), organic flocculants (such as polyacrylamide), or adsorbents (such as activated carbon and zeolite) are added. Or it is the processing method of the contamination processing target object characterized by adding 1 type (s) or 2 or more types among adsorption agents. That is, in the case of contaminated water treatment, considering the presence of soluble DXNs in the B mud slurry, activated carbon and zeolite based on PAC (polyaluminum chloride), slaked lime, etc. It is preferable to add an adsorbent such as A to the mud slurry. In the case of contaminated mud treatment, taking into account that the A mud slurry itself does not become excessively resistant to B mud dewatering and that there are soluble DXNs in the B mud slurry, trapping harmful substances more reliably. It is means to do.

  Claim 5 of the present invention is the treatment method according to any one of claims 1 to 4, wherein the B mud slurry in the treatment of contaminated water includes clay or stone powder (calcium carbonate, silica stone powder, etc.). 1 or more types of these are added, It is a processing method of the contamination processing target object characterized by the above-mentioned. That is, in the case of treatment of contaminated water, since the concentration of the B mud slurry is changed, mud such as clay or stone powder is mud if necessary.

  Claim 6 of the present invention is the treatment method according to any one of claims 1 to 5, wherein the B mud slurry contains an inorganic flocculant (PAC, sulfate band, slaked lime) in the case of treatment of contaminated water. , Polysulfate, etc.), organic flocculants (polyacrylamide, etc.), or one or more of agglomeration / solidification materials such as cement and lime-based materials are added. One or two or more kinds of lime-based and magnesia-based agglomeration / solidification materials are added. That is, in the case of contaminated water treatment, in order to insolubilize DXNs and the like trapped in the dewatered cake, an inorganic or organic flocculant or an agglomeration / solidification material such as cement or lime is added to the B mud slurry. May be added. In the case of treatment of contaminated mud, the B mud slurry is added with an inorganic coagulating / solidifying material in order to insolubilize (aggregate / contain) DXNs and the like trapped in the dewatered cake.

A seventh aspect of the present invention is characterized in that in the treatment method according to any one of the first to sixth aspects, a part of the beginning of the outflow of the A mud filtrate in the dewatering process is recovered in the B mud slurry. It is the processing method of the contamination processing target. In other words, if the pipes to dewatering equipment such as a filter press share A mud / B mud, the residual B mud in the previous process pipe and the next process A mud are mixed at the start of the next process, and the A mud Since DXNs and the like are also mixed in the filtrate, a part of the A mud filtrate begins to be recovered in the B mud slurry.

Claim 8 of the present invention is the treatment method according to any one of claims 1 to 7 , wherein in the case of treatment of contaminated water, the contaminated water obtained by washing the facility is solid-liquid separated and the supernatant is obtained. This is a method for treating a contaminated object to be treated, wherein water is reused as washing water, and the precipitate is supplied as B mud slurry to the next step. In other words, this is the case of contaminated water (B mud slurry) generated during cleaning operations when dismantling the waste incineration facility. In order to reduce the final treatment amount of contaminated water, the recovered contaminated water is solid-liquid separated in a storage tank or the like. The supernatant water is reused as washing water.

  According to the present invention as described above, the mud wrap method using a filter press or the like is used, and the B mud slurry such as contaminated water or contaminated mud is dehydrated using the A mud layer composed of the mud material as a precoat layer, DXNs are trapped in dewatered cakes (A mud and B mud) and sealed by adsorption, insolubilization, etc., so that treatment of contaminated water and mud soil containing hazardous substances such as DXNs and heavy metals is relatively easy. Simple processing equipment and processing steps can be performed at low cost, and harmful substances such as DXNs can be reliably captured to obtain drainage that is less than the discharge standard.

In the processing method according to claims 1 to 8, a filter press in which a plurality of filter chambers are arranged in the pressing direction is used for dewatering the A mud slurry and the B mud slurry, and from the inlets of the plurality of filter chambers. An air pressure is supplied from the outside to the driving flow path formed continuously in the pressing direction to primarily remove the residual B mud at the driving port, and then a scraper having a shape capable of closing the cross section of the driving flow path is used as the driving flow. perform secondary removed by passing through the road, then intends row tertiary removed by passing the driving passage Shimizu.

Schematic procedure in the case of using the this filter press, the filter press the A mud implantation → B mud implantation and pressurized dewatering → Hirakiwaku (dehydrated cake extraction) →閉枠→→→ A mud implantation → B mud implantation and pressure Dehydration → Open frame (take out dehydrated cake) → Close frame → → → Repeat the same cycle. In addition, B mud slurry composed of contaminated water etc. with A mud layer as filter and adsorption layer is dehydrated, solid-liquid separated into dehydrated cake and filtrate, DXNs etc. in dehydrated cake (A mud and B mud) Of harmful substances by trapping, adsorption, insolubilization (solidification), etc.

  As shown in the above-mentioned roles and procedures of A mud and B mud, naturally, if the B mud composed of clean A mud, which is a filter layer, and harmful polluted water, etc. are mixed in the treatment process, the treatment of the present invention. The meaning of technology is reduced, while A mud and B mud are driven alternately. In order to prevent the mixing of A mud and B mud, it is ideal that the A mud and B mud storage / mixing tank, the driving pump and the piping system are separated separately from each other.

  However, even in this case, the driving port in the filter press following the driving piping is naturally one system in structure, and if the driving is performed according to the above procedure, the previous process B is performed at the time of the next process A mud driving. The next step A mud is mixed with the mud. In view of this, the B mud remaining in the inlet of the filter press is removed and washed before the A mud is placed in the next step.

  Perform primary removal by air pressure, secondary removal by plunger, etc. (multiple times as necessary), and tertiary removal by fresh water to remove B mud remaining in the filter press inlet before A mud in the next process. Can be completely removed and washed, and the next process A mud can be completely prevented from mixing with the previous process B mud.

In the processing method of the above claims 1 to 8, A mud slurry and B mud slurry filter cloth provided on driving port of filter chamber of a filter press for performing the dewatering process of the fixing member (flange-like filter cloth fixed plate) auxiliary filter cloth continuous to the surface of the filter cloth is that provided.

Basic mechanism of dehydration generic filter press, by implanting pressure mud, only water in the muddy water (strictly smaller ultrafine earth content than the filter cloth th passes) will pass through the filter cloth, larger filter cloth th Solid particles can be separated by the soil particles remaining inside the filter cloth. On the other hand, from many of the past examples of filter press dehydration, the dehydrated cake as a whole can be dehydrated as required, but it has been confirmed that the dewatered state near the center of the cake is not sufficient and is semi-solidified.

  This factor can be presumed as follows from the basic mechanism and the filter plate structure described above. (1) There is a hooked filter cloth fixing plate for fixing the filter cloth around the insertion port at the center of the filter plate. (2) The filter cloth fixing plate is made of, for example, bakelite and has a material and a structure that do not allow moisture to pass through. (3) Therefore, the dehydrated state is remarkably inferior in the vicinity of the center of the cake compared with other parts. (4) Furthermore, in the case of the Diolap method, it is also assumed that the B mud layer is completely wrapped with the A mud layer so that the B mud does not directly contact the filter cloth (if the B mud directly contacts the filter cloth, DXNs etc. are very likely to be mixed into the filtered water), but in the place where the moisture on the central side from the groin is not allowed to pass through the water, the formation of the A mud layer is impossible because the moisture does not pass. is there. On the contrary, the formation of the A mud layer is certain on the filter cloth surface through which moisture permeates.

  Focusing on these, the dehydration of water in the mud located at the center of the groin can be promoted, and the formation of the A mud layer can be performed reliably. That is, in order to ensure water permeability up to the immediate vicinity of the driving hole, an auxiliary filter cloth was stuck on the bowl-shaped filter cloth fixing plate. According to this method, (1) a uniform dehydrated cake was formed including the center of the dehydrated cake. (2) A mud layer was formed as close as possible.

Claim 9 of the present invention is the processing method according to any one of claims 1 to 8, toxic substances in drainage of B mud slurry is decomposed by the photocatalytic, a filtration by to Rukoto solids It is the processing method of the pollution processing target object characterized.

According to a tenth aspect of the present invention, in the treatment method according to the ninth aspect , the harmful substance is decomposed by an oxide phase mainly composed of a silica component (first phase) and a metal oxide phase other than silica (second phase). ) And a woven fabric of silica-based composite fibers having a photocatalytic function in which the abundance ratio of at least one constituent component of the second phase is gradually increased toward the surface layer of the fibers. This is a method for treating an object to be contaminated, characterized in that it is carried out by a purification device comprising a filter and an ultraviolet lamp.

The inventions of claims 9 and 10 are applied to a treatment method (inventions of claims 1 to 8 ) for washing contaminated water, contaminated mud, etc., and DXNs which are difficult to dissolve in water and adhere to the solid content. And the like, a dehydration step of adsorbing DXNs dissolved in water such as washing water, and a step of decomposing soluble DXNs in the filtrate after this step with photocatalyst fibers.

First, in the dewatering process, the precoat layer (A mud layer), which is a feature of the mud wrap method, is used, and the solid content in the contaminated water (B mud) containing DXNs is captured as a dehydrated cake and soluble in the precoat layer. Most of DXNs are adsorbed (dehydration step of the invention of claims 1 to 8 ). Next, soluble DXNs and the like in the filtrate discharged in the dehydration step are decomposed with a highly functional photocatalyst.

  Highly functional photocatalytic decomposition is a fiber comprising a composite oxide phase of an oxide phase (first phase) mainly composed of a silica component and a metal oxide phase (second phase, titanium oxide, etc.) other than silica. A filter comprising a woven fabric of silica-based composite oxide fiber having a photocatalytic function, wherein the abundance ratio of at least one component of the second phase increases toward the surface layer of the fiber, and an ultraviolet light irradiation lamp (See Japanese Patent Application Laid-Open No. 2003-10612).

  Conventionally, fine solids with DXN attached thereto are taken into the dewatered filtered water, resulting in insufficient reduction of DXNs. For example, a filter medium (nonwoven fabric) of photocatalyst fibers is used in the subsequent DXN decomposition process. Etc.) and the degradation rate was reduced, resulting in a decrease in the processing amount. In addition, there is a problem that the load balance between the solid-liquid separation process by dehydration and the separation / decomposition process of DXNs becomes unbalanced, and there is a drawback that the process management becomes complicated and the processing cost becomes high.

  The highly functional photocatalytic degradation of the present invention is less likely to cause the titanium oxide to fall off compared to the conventional glass filter having a titanium oxide coating on the surface, and furthermore, because the titanium is concentrated on the filter surface, high decomposition efficiency is obtained. Have the characteristics In addition, the solid content in water such as washing water, or the content and quantity ratio of insoluble or soluble components such as DXNs vary greatly depending on the demolished property. However, in the present invention, the separation and decomposition function of DXNs and the like in the dewatering and subsequent drainage treatment processes is excellent, so load adjustment is easy and efficient treatment is possible. Become.

  The present invention utilizes a mud wrap method using a filter press or the like, dewatering B mud slurry such as contaminated water or contaminated mud using A mud layer composed of mud material as a precoat layer, and dewatering cake (A mud and B mud) traps DXNs, heavy metals, etc. by trapping, adsorbing, insolubilizing, etc., and has the following effects.

  (1) Treatment of contaminated water and contaminated mud containing harmful substances such as DXNs and heavy metals can be performed at a low cost with relatively simple treatment facilities and treatment steps. Compared to the conventional case, it is extremely advantageous in terms of on-site maintenance and cost.

  (2) Capable of capturing harmful substances such as DXNs and heavy metals, and obtaining filtered water below the discharge standard.

Further, in the present invention, it is removed and cleaned mouth residue B mud implantation in a filter press, and by Tei Rukoto an auxiliary filter cloth filter cloth fixed plate, the following effects.

  (1) Residual B mud remaining in the injection port can be completely removed, and B mud is not mixed with the A mud layer, and a clean A mud layer that is a filter layer ensures that DXNs and the like are reliably added to the dehydrated cake. It is possible to reliably obtain filtered water that is contained and that is less than the discharge standard.

  (2) The auxiliary filter cloth can form a uniform dehydrated cake with no semi-solidified or semi-liquefied state including the center of the dehydrated cake, and the A mud layer can be formed as close as possible to the injection port. In addition, since a clean A mud layer is formed in the entire filter chamber, DXNs and the like can be reliably contained in the dehydrated cake, and filtered water below the discharge standard can be reliably obtained.

  (3) The general-purpose filter press can be used almost without modification, and the processing technique of the present invention can be implemented with a low-cost processing facility.

  Further, in the present invention, soluble DXNs in the filtrate after the dehydration step in the treatment method for washing contaminated water, contaminated mud, etc. are decomposed by a purification device comprising photocatalyst fibers and the solid content is separated by filtration. As a result, the following effects can be obtained.

  (1) The filtered water after the dehydration process can be reliably reduced to below the discharge standard for DXNs and discharged.

  (2) By using high-performance photocatalytic decomposition, higher decomposition efficiency can be obtained than before, and it is possible to surely reduce DXNs and the like in filtrate and increase the treatment amount.

  (3) Furthermore, since the separation / decomposition function of DXNs and the like in the drainage treatment process is excellent, load adjustment is easy and efficient treatment is possible.

  Hereinafter, the present invention will be described based on the illustrated embodiment.

[First Embodiment]
This first embodiment is an example applied to the treatment of contaminated water containing DXNs, heavy metals, and the like that are generated during a cleaning operation when dismantling a waste incineration facility. FIG. 1 is a schematic diagram of an equipment flow showing one example of the processing equipment of the first embodiment for carrying out the basic processing method of the present invention. FIG. 2 is a cross-sectional view showing processing steps in the filter press of the present invention in the order of steps.

In the embodiment of FIG. 1, the treatment facility according to the present invention is installed in a site for demolition of an incineration facility, and roughly shows contaminated water W ₀ containing DXNs and the like generated by washing with the washing nozzle 1 by a filter press mud. Rapid dehydration and volume reduction solidification processing using a lapping method, DXNs etc. are confined in dewatering cake C, this dewatering cake C is incinerated, etc., drained water W is discharged below the discharge standard, Mainly from the upstream side, the contaminated water collecting pit 2, gravel sand separator 3, supernatant water tank 4, storage tank 5, A mud mixing tank 6, B mud mixing tank 7, filter press 8, drainage tank 9, It comprises a neutralization tank 10 and a water discharge monitoring tank 11. The details of the processing steps are as follows (see FIG. 1).

(1) Contaminated water W ₀ after washing by high-pressure jet of the washing nozzle 1 is collected in the contaminated water collecting pit 2, and the gravel sand is removed by the gravel sand separator 3, and then stored in the transfer pump 20. The supernatant water is separated while being stirred by the stirrer 21. Here, in order to reduce the final treatment amount of the contaminated water, the supernatant water W ₁ of the storage tank 5 is sent to the supernatant water tank 4, and this supernatant water W ₁ is supplied to the washing nozzle 1 by the high-pressure injector 22 and recovered / recycled. Use.

(2) Precipitated sludge water W ₂ containing DXNs in the storage tank 5 (incinerated ash, residue (residue in the facility, sand, rust, refractory bricks in the furnace, etc.)) is mixed with B mud by the transfer pump 23 It sends to the tank 7 and B mud slurry _BS is produced. If necessary, a treatment material B described later from the dissolution tank 14 or a mud material D described later from the mud tank 12 is added. On the other hand, the A mud mixing tank 6, sends a mud material D to be described later from Sakudoroso 12, with the addition of treatment materials A to be described later from the dissolution tank 13, to produce the A mud slurry A _S.

(3) First, the A mud slurry A _S is driven into the filter chamber of the filter press 8 by the driving pump 24, and then the B mud slurry B _S is driven by switching the piping. As shown in FIG. 2, when the B mud slurry B _S is placed inside the A mud slurry A _S placed in the filter chamber 8a, the dewatering of the A mud slurry A _S proceeds, and the A mud slurry A _S is placed around the filter chamber. A mud precoat layer is formed, and dewatering of the B mud proceeds through the precoat layer and the filter cloth, and solid-liquid separation into dewatered cake C (A mud and B mud) and filtered water W is performed. After dehydration is completed, the open frame is removed, and dewatered cake C is taken out.

  Here, in the contaminated water generated in the cleaning operation at the time of dismantling of the waste incineration facility, there are ash and residues containing DXNs or soluble DXNs. A mud is a filter and adsorption layer for capturing DXNs, and the main material is composed of mud material D made of water-insoluble inorganic particles such as stone powder (calcium carbonate, silica powder, etc.) or bentonite. As this mud material D, it is preferable to use a material having a particle group of 75 μm or more of 10% by mass or less and an average particle size of 10 μm or less.

  In addition, most of it is derived from SS, but considering the existence of soluble DXNs, as an A mud treatment material A, inorganic flocculants (PAC, sulfate band, slaked lime, polyiron sulfate, etc.) It is preferable to add an adsorbent (activated carbon, zeolite, etc.) based on organic coagulant (polyacrylamide, etc.).

  Since the B mud slurry has a change in concentration (the wash water is expected to have a low concentration), the mud slurry is mudded with a mud material D made of clay or stone powder (calcium carbonate, silica powder, etc.) as necessary. In addition, in order to insolubilize DXNs trapped in the dehydrated cake, the B mud slurry contains an inorganic flocculant (PAC, sulfate band, slaked lime, polyiron sulfate, etc.), an organic flocculant (polyacrylamide, etc.) or Cement or lime-based agglomeration / solidification material may be added as the treatment material B. When immediately incinerated, this treatment material B need not be added.

  (4) DXNs are trapped in the dehydrated cake C (A mud and B mud) by trapping, adsorbing, insolubilizing, etc., by the precoat layer configuration and the treatments and additives as described above. The volume-reduced dewatered cake C from the filter press 8 is conveyed by the belt conveyor 25 and melted or baked at a processing facility or the like conforming to the new discharge standard. On the other hand, the filtrate W is discharged through the drainage tank 9, the neutralization tank 10, and the water discharge monitoring tank 11 to the discharge standard (DXN 10pg-TEQ / L) or less. The filtrate W in the drainage tank 9 is returned to the supernatant water tank 4 and reused as washing water.

In the example shown in the figure, the piping to the filter press 8 shares A mud and B mud, so that the residual B mud in the previous process piping and the next process A mud are mixed at the start of the next process, and the A mud is filtered. since such DXN acids is mixed in, returning some of the start output of the a mud drainage to B mud mixing tank 7 (not shown), to recover the B mud slurry B _S.

[Second Embodiment]
The target of the second embodiment is contaminated mud, which is fine-grained soil in which the pollutants after the coarse separation of contaminated soil and harbors and lakes containing DXNs and heavy metals are concentrated. For example, the contaminated bottom sediment that has been drowned is adjusted with water (or water during vibration sieving) so that coarse particles can be easily separated according to its properties (softness), and then trommel, vibration sieving, scraping gate Separate coarse-grained soil that does not contain harmful substances with a hydrocyclone. Fine-grained soil containing harmful substances after this coarse-grain separation is the target of treatment. The treatment facility can be treated in the same manner using the treatment facility similar to that in FIG. 1 except that the portion related to the contaminated cleaning water on the upstream side in FIG. 1 is different.

  A mud that serves as a supplement / adsorption layer for harmful substances such as DXNs is a mud slurry made of water-insoluble inorganic particles having a particle group of 75 μm or more and 10 mass% or less and an average particle diameter of 20 μm or less. If necessary, add flocculant and adsorbent. As the water-insoluble inorganic particles, stone powder obtained by pulverizing minerals such as calcium carbonate and quartzite powder to a predetermined particle size, various clays such as bentonite and kaolinite, or one or a mixture of two or more kinds of coal ash can be preferably used. . Among these, coal ash preferably contains about 2 to 20% of unburned carbon capable of adsorbing harmful substances. However, depending on the properties of the coal ash, even if it is within a predetermined particle size range, the particle size distribution may be narrow and the dewatering resistance of the A mud itself may be too small. In this case, before the A mud is completely filled in the filter chamber of the filter press, dehydration proceeds, and it becomes difficult to form a uniform A mud cake. For this reason, if necessary, dehydration resistance is adjusted by adding clay such as bentonite to coal ash. The addition amount of bentonite is usually preferably 50% or less with respect to coal ash.

  These mud materials are hydrated to form a slurry having a water content of 300 to 2000%, preferably a water content of 500 to 1700%. When the water content ratio is higher than 2000% (dilute), the amount of slurry placed on the filter press increases, the dehydration time becomes longer, and the material separation is large and the handling property is deteriorated. On the other hand, when the moisture content is lower than 300% (concentrated), the thickness of the A mud layer is not uniform, and the A mud needs to be designed based on the thinnest part. The layer thickness increases and the amount of contaminated mud (B mud) that can be dewatered decreases.

  In consideration of the fact that this mud slurry does not become an excessive resistance to dewatering of the contaminated mud slurry (B mud) and there is a possibility that soluble DXNs and heavy metals exist, PAC, sulfate band, poly iron sulfate It is preferable to add an acidic flocculant such as activated carbon and / or an adsorbent such as activated carbon and zeolite. The addition amount of acidic flocculants such as PAC, sulfate band, and polyiron sulfate is 30 to 200 kg / tds · A (addition amount per 1 ton of mud material dry matter). The A mud layer has a function of neutralizing the alkaline drainage because the agglomeration / solidification material added to the contaminated mud described later is generally alkaline. The effect of this neutralization also shows the effect of properly exhibiting the capacity of the adsorbent described later. That is, depending on the type of organic matter contained in the sediment, the organic matter (COD, TN) may be easily eluted into the filtrate due to the action of alkali. Have a function of adjusting to the following). Depending on the type and amount of flocculating / solidifying material, B mud filtrate may not be neutralized with only the acidic flocculating agent. By using sodium aluminate together, the alkali neutralizing ability of A mud is improved. It can also be made.

  Next, in order to increase the dewatering speed and solidify / insolubilize DXNs trapped in the dewatered cake, B mud is prepared by adding a coagulating / solidifying material to the contaminated mud slurry.

  As agglomeration / solidification materials, various portland cements, slaked lime, quicklime or various cement-based, lime-based, cement / lime-based solidification materials, and magnesia and magnesia-based magnesia-based aggregation / solidification Add ingredients. These agglomeration and solidification materials are selected appropriately by a blending test using actual target mud.

In addition, as magnesia, the light baking magnesia of 10-150 m < ² > / g obtained by baking magnesium carbonate etc. at about 900 degreeC by a BET specific surface area can be used conveniently. The fineness is preferably a 100 mesh (aperture 149 μm) under product, more preferably a 200 mesh (aperture 74 μm) to 300 mesh (aperture 48 μm) under product.

  The magnesia-based solidified material is based on magnesia and added with calcium perphosphate, sodium heavy perphosphate, sodium hexametaphosphate, sodium pyrophosphate, sulfate band, iron sulfate, various gypsum, blast furnace slag, various Portland cement, alumina cement, etc. In addition, the agglomeration performance and solidification strength of magnesia are enhanced. Generally, the amount of these additives is 20% by mass or less based on magnesia.

  The amount of magnesia and magnesia-based solidified material added to the contaminated mud is usually 30 to 200 kg / tds · B, and the mixing time with the contaminated mud slurry is preferably 0.5 to 3 hours. Magnesia and magnesia-based solidified materials are characterized by a hydration reaction during the mixing time with contaminated mud and aggregate the soil particles extremely efficiently, which increases the dehydration rate and greatly improves the solidification strength. . For this reason, when the stirring time is short, a sufficient dehydration rate cannot be obtained. On the other hand, if the stirring time is too long, the amount of unreacted material that contributes to increasing the strength of the dehydrated cake after dehydration decreases, and the elongation of cake strength decreases.

  These A mud and B mud are placed in the filter press in the order of A mud and B mud. Even if the filter press uses a low-pressure (about 0.5 MPa) apparatus, a high-strength cake can be obtained by the effect of the agglomeration / solidification material added to the B mud, but a high-pressure (about 4 MPa) apparatus may be used. . In this case, the moisture content of the cake is lowered and a higher cake strength is obtained, so the amount of the agglomeration / solidification material added may be reduced. Moreover, you may use the normal flocculant which does not have a solidification function.

This example is the case of the contaminated mud according to the second embodiment.
(1) Target polluted mud The characteristics of the target polluted mud used in the examples and comparative examples are shown in Table 1 below. The filter press dewatering was performed using muddy water obtained by classifying and washing the target mud and removing coarse particles (under 0.3 mm).

(2) Treatment materials The treatment materials used in the examples and comparative examples are as follows.
Coal ash: 8% unburnt carbon boiler ash bentonite: Aso, manufactured by Nippon Bentonite Industries Co., Ltd. Polyaluminum chloride: 10% alumina aqueous solution, Asada Chemical Co., Ltd. magnesia: light-burned magnesia, BET Specific surface area 19 cm ² / g
Slaked lime: Special S (particle size of 200 mesh or less) manufactured by Ube Materials Co., Ltd.

(3) For the dehydration, a small filter press (□ 400 × 15 mm × 9 chambers (volume: 15 liters), pump pressure: 0.4 MPa, flow rate: 0.8 m ³ / h) was used.

(4) Freeness test The following measurements were conducted on the filtrate to evaluate the dehydration effect.
pH: JIS-K-0102.12.
COD: JIS-K-0102.17
TN: JIS-K-0102.45
TP: JIS-K-0102.46
DXN: Official method analysis

(5) Evaluation of dehydrated cake: cone index and elution test of dehydrated cake The dehydrated cake obtained in (3) above was thawed, passed through a 9.5 mm sieve, and then compacted into a mold having a diameter of 10 cm and a capacity of 1 liter. The cone index was measured by a method according to JIS A1228.

The amount of DXNs eluted from the dehydrated cake is determined after the dehydrated cake is thawed at the age of 7 days and passed through the method prescribed in the Act on the Prevention of Marine Pollution and Maritime Disasters (Sea Defense Law ) The mixture was shaken with distilled water adjusted to pH 7.8 to 8.3 for 6 hours and filtered with 1 μm glass fiber filter paper, and DXNs in the test solution were measured.

Table 2 shows the results of the dehydration experiment by the filter press (Examples 1 to 3, Comparative Examples 1 and 2). Under the dehydration conditions within the scope of the present invention, the dehydration time is shorter than that of a normal dehydration method (combination of PAC and slaked lime as a general coagulant), and the concentration of DXNs is determined based on the drainage due to the effect of the precoat layer. It was confirmed that the following can be made. Moreover, pH became a low alkali of 10 or less, and COD, TN, and TP became values below normal dehydration. Furthermore, it was confirmed that the strength of the dewatered cake was 7 days old and a high strength equivalent to or higher than the second type improved soil having a wide range of uses (corn index immediately after compaction and compaction: 800 kN / m ² ) or more was obtained. The amount of DXNs eluted from the dehydrated cake was insolubilized by the aggregation and solidification of the magnesia-based solidified material, and in the range of the present invention, the value was 1 pg-TEQ / L or less.

[Third Embodiment]
In this third embodiment, when a filter press is used for dewatering in the treatment of contaminated water such as washed contaminated water, contaminated mud such as dredged soil, and contaminated soil, removal and washing of residual B mud in the injection port in the filter press And a processing technique that forms a cake that is completely lapped with the A mud layer up to the immediate vicinity of the driving hole and is uniformly dehydrated. FIG. 3 is an example applied to a treatment facility for cleaning contaminated water.

  In FIG. 3, except for the structure of the filter press and piping, etc., it is the same processing equipment as the processing equipment of the first embodiment, and is the same iolap construction method as the first embodiment, and contains harmful substances such as DXNs. It is a technology that reliably captures harmful substances such as DXNs and obtains drainage below the discharge standard with simple processing equipment and processing methods for processing contaminated water and contaminated mud. Furthermore, the B mud slurry composed of contaminated water etc. with the A mud layer as a filter and adsorption layer is dehydrated, solid-liquid separated into dehydrated cake and filtrate, DXNs etc. in the dehydrated cake (A mud and B mud) Of harmful substances by trapping, adsorption, insolubilization (solidification), etc. In general, when using a filter press, the general procedure is as follows: A mud is placed in the filter press → B mud is placed and pressurized dewatered → Open frame (dehydrated cake removal) → Closed frame → → → A mud is placed → B mud is placed and pressurized Dehydration → Open frame (take out dehydrated cake) → Close frame → → → Repeat the same cycle.

  As shown in the above-mentioned roles and procedures of A mud and B mud, naturally, if the B mud composed of clean A mud, which is a filter layer, and harmful polluted water, etc. are mixed in the treatment process, the treatment of the present invention. The meaning of technology is reduced, while A mud and B mud are driven alternately.

(A) Cleaning of filter press In order to prevent the mixing of A mud and B mud as described above, as shown in FIG. 3, mixing tanks 6 and 7 for A mud and B mud, driving pumps Ideally, the 24 and the driving pipe 40 are separated separately. However, even in this case, the injection port in the filter press following the piping is naturally one system in structure. Next step A mud will be mixed. In view of this, the B mud remaining in the inlet of the filter press is removed and washed before the A mud is placed in the next step.

  As shown in FIGS. 3 to 5, the filter press 8 is configured by arranging a plurality of filter chambers 42 formed by a pair of filter frames 41 in the press direction (center axis). The filter cloth 43 is affixed on the surface. A filter-like filter cloth fixing plate 44 is attached to the end of the filter frame 41 on the center axis side, and a driving hole 45 is formed by the filter cloth fixing plate 44. The continuous flow path 46 is formed in the center of the press by being continuous.

  The outline of removal / cleaning procedure is as follows: A mud blasting → B mud blasting / pressure dewatering → B mud removal / washing in the throat → Open frame (dehydrated cake removal) → Closed frame →→→ A mud bombardment Pressurized dehydration → Removal and cleaning of residual B mud in the inlet → Open frame (dehydrated cake removal) → Closed frame →→→ Repeat the same cycle. In addition, since this method discharges the residual B mud in the injection port and the cleaning water, a discharge pipe 47 is added to the applied filter press 8 as shown in FIG.

  The basic specific procedure for removing and cleaning residual B mud in the inlet is shown below.

  (1) After the B mud is placed and pressurized and dehydrated, the residual B mud in the inlet is removed primarily by air pressure. That is, first, the compaction state of the B-mud in the inlet is released. As shown in FIG. 3, a compressor 49 is connected to the driving pipe 48 via a three-way valve to supply air into the driving flow path 46 in the press.

  (2) Next, secondary removal is performed. As shown in FIG. 5, the secondary removal is performed by inserting a plunger (made of rocket-like foamed urethane rubber or the like, a diameter slightly larger than the inner diameter of the driving port) 50 from the plunger insertion hand hole 51 of the driving pipe 48. Then pressurize the back of the plunger (air, clean water, clean bentonite water, etc.). The plunger 50 receives the pressure applied on the back surface, and is discharged from the discharge pipe 47 and collected together with the residual B mud while scraping the residual B mud in the driving port. Repeat the plunger scrape as many times as necessary.

  (3) Next, tertiary removal is performed. Tertiary removal is performed by driving fresh water or the like through a required amount through the flow path 46. As shown in FIG. 3, a water tank 52 such as fresh water is installed and connected to the A mud driving pipe 40 a via a three-way valve. The A mud slurry driving pipe 40 a is connected to the non-press side of the driving pipe 48, and the B mud slurry driving pipe 40 b is connected to the press side of the driving pipe 48. After these series of cleaning operations, the process proceeds to the next step.

  As shown in FIG. 3, the cleaning contaminated water stored in the drain tank 53 can be circulated. In addition, the plunger should be scrutinized, dimensioned, shaped, and material so that a scrape effect can be obtained in accordance with the cake properties and filter press structure.

  Further, depending on the muddy water state such as containing a lot of sand, it is assumed that dehydration is excessively promoted and the dehydration and hardening reaches the muddy soil in the pouring mouth. In such a case, there is a possibility that the method based on the simple primary to tertiary removal described above cannot be used. In such a case, a mechanical drilling method is used prior to the primary removal. This can be handled by a conventional insertion rotation type maintenance facility for drainage facilities (the famous trade name is Kantool), and after the perforation penetration, the above-mentioned primary to tertiary removal are used in combination.

  By the way, this technology originally has a feature that a general-purpose filter press can be applied almost as it is (without major modification). Therefore, various filter presses can be used in actual construction. Therefore, it is expected that the structure of the inner surface of the driving hole is also various. For example, a structure in which the inner surface of the driving hole is not smooth is conceivable. Basically, it is premised that plunger scrape can be performed as described above, so it is necessary to make a prior modification to a structure capable of plunger scrape, but these are small-scale and low-cost modifications. If you look, there is no problem.

(B) Structure of filter press The structure of the filter plate of the general-purpose filter router press is shown in FIG. The basic mechanism of the finer press dewatering is that when the pressure muddy water is driven, only the water in the muddy water (strictly, ultrafine soil smaller than the filter cloth passes) passes through the filter cloth, and the soil particles larger than the filter cloth. Is left inside the filter cloth, so that solid-liquid separation can be achieved. On the other hand, the following phenomenon has been confirmed from many examples of past filter press dehydration. Although the required dehydration can be achieved for the entire dehydrated cake, the dehydrated state in the vicinity of the center of the cake C is not sufficient, and the phenomenon is a semi-solidified state or a semi-liquefied state C ′. This factor can be presumed as follows from the basic mechanism and the filter plate structure described above.

  (1) As shown in FIG. 4, a filter cloth fixing plate 44 having a hook shape for fixing the filter cloth 43 is present around the insertion port 45 at the center of the filter board. (2) The filter cloth fixing plate 44 is made of, for example, bakelite and has a material and a structure that do not allow moisture to pass through. (3) Therefore, the dehydrated state is remarkably inferior in the vicinity of the center of the cake compared with other parts. (4) It is also assumed that the B mud layer is completely wrapped with the A mud layer so that the B mud does not directly contact the filter cloth (if the B mud directly contacts the filter cloth, DXNs in the B mud etc. However, it is impossible to form the A mud layer at a location where the moisture on the central side of the groin is not allowed to pass through because moisture does not pass therethrough. On the contrary, the formation of the A mud layer is certain on the filter cloth surface through which moisture permeates.

  Paying attention to these, we devised a method that can promote dehydration of the water in the mud located at the center of the groin and ensure the formation of the A mud layer. Before discussing this devised method, we first describe this need. As shown in the above-described cleaning of the filter press, the B mud remaining in the filter press implantation port can be solved by a method of removing and washing before the A mud implantation in the next step. However, the above method cannot remove and clean mud soil in the “semi-solidified state or semi-liquefied state” existing on the outer peripheral portion from the driving port.

  On the other hand, if the semi-solid / liquid mud existing outside the pouring port completely peels and drops off as a dehydrated cake when the frame is opened, it will not be a problem at the time of mud pouring in the next process. Since it is in a state, practically, when the cake is taken out, the semi-solid / liquid mud is almost certainly attached to the filter cloth or the filter cloth fixing plate. Further, since the filter cloth fixing plate is made of a material and structure that does not allow moisture to pass through, the A mud layer is not formed on the center side of the heel diameter. Therefore, the semi-solid / liquid B mud is directly attached to the filter cloth or the like.

  Therefore, as shown in FIG. 5, an auxiliary filter cloth 60 is pasted on the bowl-shaped filter cloth fixing plate 44 in order to ensure water permeability up to the immediate vicinity of the driving hole 45. The auxiliary filter cloth 60 is attached to the inner side surface of the filter cloth fixing plate 44 and continuously integrated with the filter cloth 43. Experiments were conducted to confirm the actual effect of this method, and the following results were obtained. (1) A uniform dehydrated cake was formed including the center of the dehydrated cake. (2) A mud layer was formed up to the immediate vicinity.

  Addition of the above two methods (removal / cleaning method of residual B mud in the injection port and uniform dewatering cake formation method completely wrapped with the A mud layer by ensuring water permeability up to the immediate vicinity of the injection port) It became what was done.

(C) Correspondence to long filter press The expansion means of the Diolap method was shown above. As described above, the application target of this construction method is cleaning water treatment containing DXNs, etc. in demolition work of a waste incineration facility, and dehydration, volume reduction, insolubilization (solidification) treatment of sediments containing DXNs and the like. Regarding the dewatering / desolubilization / insolubilization treatment of the bottom sediment, the target treatment amount is generally large, so that a large filter press is naturally adopted. Large filter presses not only increase the size of the filter frame, but also increase the number of filter chambers. Accordingly, the extension of the injection port line becomes longer, and the flow resistance of the semisolid / liquid mud remaining in the injection port increases. Therefore, the plunger removal / cleaning method using air pressure and pressure water shown in the above-mentioned filter press cleaning may have a situation in which the flow resistance is greater than the air / water pressure. Cleaning is difficult or impossible.

  Therefore, a removal / cleaning method has been devised when the length of the inlet port is long (high flow resistance), such as when using a large filter press. As shown in FIG. 6, a branch-type in-mouth residual mud discharge pipe 70 (hereinafter referred to as a branch discharge pipe) is provided in a form that divides the middle of the injection flow path. By providing the branch discharge pipes 70 at arbitrary intervals, it is possible to avoid the relationship that the flow resistance force becomes larger than the applied pressure. At the same time, an automatic opening / closing control valve 71 is provided in the branch discharge pipe 70 to add an opening / closing control function such as arbitrary / interlocking.

  A specific control example of the branch discharge pipe is shown below. Four branch discharge pipes 70 are closed → A mud driving → B mud driving and pressurization and dehydration are completed, branch discharge pipe 70a is opened, branch discharge pipes 70b to 70d are closed, and the end of the injection port is divided to branch discharge by air pressure. One stage of residual mud up to the pipe 70a is removed. Next, the branch discharge pipe 70a is closed, 70b is opened, 70c and d are closed, and then air pressure is applied to remove the residual mud between 70a and 70b in two stages. Repeat steps 3 and 4 for the same procedure. In this way, the in-pipe flow resistance is once released stepwise for each section, and thereafter, washing is performed by the same method using the plunger and fresh water as described above. Although this method is an example, it is possible to cope with a long filter press by appropriately using the above-described method or the like depending on the situation.

[Fourth Embodiment]
This fourth embodiment is a processing technology for decomposing harmful substances such as DXNs in B mud filtrate with a photocatalyst, filtering out solids, and treating the filtrate to a discharge standard or lower, mainly for cleaning contaminated water, etc. Applies to the treatment of contaminated water. It can also be applied to the treatment of contaminated mud such as dredged soil and contaminated soil. FIG. 7 shows an example applied to the treatment of cleaning contaminated water.

  The embodiment of FIG. 7 is, for example, DXNs processing technology for facility cleaning wastewater at the time of dismantling of the waste incineration facility, and the contaminated water generated in the cleaning operation is incinerated ash and facility structure surface exfoliated matter, There exist DXNs etc. which do not melt | dissolve in the water adhering to solid content comparatively firmly as harmful organic substances, DXNs etc. which melt | dissolved in the washing water, etc. This processing technique is a method for efficiently separating and decomposing DXNs and the like having different forms of existence, and is roughly divided into two stages. That is, the first step is a solid-liquid separation in contaminated water and a dehydration step to remove a part of DXNs dissolved in water, and the second step is a photocatalytic decomposition such as DXNs dissolved in filtrate or DXNs. It consists of a process of separating the adsorbed solid content. The drainage of the drained cake is reduced to less than the discharge standard for DXNs, and the dehydrated cake is melted or baked (incineration) at a treatment facility that complies with the new discharge standard (for example, an industrial waste incineration facility). Is an environmental load reduction type treatment method that decomposes

  More specifically, in FIG. 7, the dehydration step is the same as in the first embodiment, and the same processing apparatus as in the first embodiment is used except for the processing apparatus for B mud filtrate. That is, as in the first embodiment, the A mud is an adsorbed layer of adsorbed solids such as DXNs and water-soluble DXNs, and mud material D such as stone powder and bentonite is added to the fresh water, which is necessary. Accordingly, an adsorbent (treatment material) A such as an inorganic or organic flocculant, activated carbon or zeolite is added.

  Next, in the filter press 8, B mud is driven in succession to A mud. B mud is sedimented sludge water excluding supernatant water, dehydrated through a precoat layer (A mud layer), and solid-liquid separated into dehydrated cake C and filtrate W. When the solid content concentration in the B mud is low, this can be dealt with by adding the mud material D. Note that a cement-based or lime-based solidifying material (treatment material) B can be added to the B mud as necessary to prevent re-mudging of the solid content. However, the addition of the solidifying material B is not necessary when carrying out immediately for incineration without temporary placement.

  As described above, most of the water-soluble or insoluble DXNs can be finally captured in the dehydrated cake C by the dehydration step alone. On the other hand, the drainage water W after dehydration has been reduced to a drainage standard (DXN 10 pg-TEQ / L) or less via a drainage tank 9 and, if necessary, a neutralization tank 10 and a monitoring tank 11 in a public water area. In the present invention, DXNs are decomposed by the photocatalyst fiber. This step is performed by taking the filtrate from the filtrate tank 9 or the neutralization tank 10 into the decomposition device 30 using photocatalyst fibers, and decomposing it using a plurality of decomposition devices 30 in series or in parallel according to the amount of filtrate. Usually, this decomposition is performed by circulating filtered water, and therefore a water storage tank 31 having a necessary capacity is also provided. The filtered water that decomposes DXNs and the like is finally discharged from the monitoring tank 11 to the public water area.

  In addition, although the above demonstrated the case where a filter press was used, not only this but another dehydration processing equipment may be sufficient.

It is the schematic of the equipment flow which shows one example of the processing equipment for enforcing the basic processing method of this invention. It is sectional drawing which shows the fundamental process process in the filter press of this invention in process order. It is the schematic of the equipment flow which shows an example of the processing equipment which added the washing | cleaning method of the filter press etc. to the basic processing method of this invention. It is sectional drawing which shows the filter plate structure of a general purpose filter press, a cake image, etc. It is sectional drawing which shows the filter plate structure, cake image, etc. of the filter press of this invention. It is sectional drawing of the press which shows the removal and washing | cleaning of the mud in the implantation inlet channel of this invention in a long filter press. It is the schematic of the equipment flow which shows an example of the processing equipment which added the filtered water process by the photocatalyst to the basic processing method of this invention.

Explanation of symbols

A _S ... A mud slurry B _S ... B mud slurry C ... Dehydrated cake D ... Mud material W ₀ ... Contaminated water W ... Filtrate 1 ... Washing nozzle 2 ... Contaminated water collecting pit 3 ... Gravel sand Separation device 4 …… Supernatant water tank 5 …… Storage tank 6 …… A mud mixing tank 7 …… B mud mixing tank 8 …… Filter press 9 …… Drainage tank 10 …… Neutralization tank 11 …… Discharge water monitoring tank 12 ... Mud tank 13 ... Dissolution tank A
14 …… Dissolution tank B
20. Transfer pump 21 ... Stirrer 22 ... High-pressure injector 23 ... Transfer pump 24 ... Driving pump 25 ... Belt conveyor 30 ... Decomposition device 31 ... Reservoir 40 ... Driving pipe 41 ... Filtration Frame 42 ... Filter chamber 43 ... Filter cloth 44 ... Filter cloth fixing plate 45 ... Implanting port 46 ... Implanting flow path 47 ... Discharge piping 48 ... Implanting piping 49 ... Compressor 50 ... Plunger 51 …… Plunger insertion hand hole 52 …… Water tank 53 …… Drain tank

Claims (10)

This is a method for treating contaminated water and / or dredged mud soil containing toxic substances and other contaminated objects to be treated. A mud slurry composed of mud material that traps toxic substances is placed in the dehydration chamber. Then, a B mud slurry composed of an object to be contaminated containing harmful substances is placed in the A mud slurry, and then the B mud slurry is dehydrated using the A mud layer as a precoat layer, and the dehydrated cake and filtrate the solid-liquid separation, a method of processing contaminated processing object you捉 reliably catching harmful substances in the dehydrated cake,
For the dehydration treatment, a filter press having a plurality of filter chambers arranged in the press direction is used, and air pressure is supplied from the outside to the implantation flow path formed in the press direction formed from the plurality of filter chamber implantation ports. Then, the residual B mud remaining in the inlet is removed first, and then a secondary scraper is formed by passing a scraper having a shape capable of closing the cross section of the inlet passage through the inlet passage, and then fresh water is supplied to the inlet passage. Perform tertiary removal by passing through,
A method for treating a contamination treatment object, wherein an auxiliary filter cloth continuous with the filter cloth is provided on a surface of a filter cloth fixing member provided at a driving port of a filter chamber of the filter press.   In the processing method of Claim 1, the mud material of A mud slurry consists of the water-insoluble inorganic particle | grains whose particle size of 75 micrometers or more is 10 mass% or less, and whose average particle diameter is 20 micrometers or less. The processing method of the contamination processing object.   In the treatment method according to claim 2, in the case of treatment of contaminated water, the water-insoluble inorganic particles are a mud material composed of one or more kinds of stone powder or bentonite, and in the case of treatment of contaminated mud, A method for treating an object to be contaminated, which is a mud material made of a mixture of one or more of clay, stone powder, and coal ash.   In the processing method as described in any one of Claim 1 to 3, 1 type or 2 types in an inorganic flocculant, an organic flocculant, or an adsorbent in the case of a contaminated water treatment to A mud slurry. In the case of the treatment of contaminated mud, the above-mentioned method is added, and one or more of inorganic coagulants and / or adsorbents are added.   5. The treatment method according to claim 1, wherein at least one of clay or stone powder is added to the B mud slurry in the treatment of contaminated water. The processing method of the object.   In the processing method as described in any one of Claim 1-5, in processing of contaminated water, in B mud slurry, it is an inorganic type flocculant, an organic type flocculant, or aggregation, such as cement and lime type, One or more of the solidifying materials are added, and in the case of processing contaminated mud, one or more of the aggregating / solidifying materials such as cement-based, lime-based, and magnesia-based materials are added. A processing method for a characteristic object of contamination treatment.   The processing method according to any one of claims 1 to 6, wherein a part of the start of the discharge of the A mud filtrate in the dewatering process is recovered in the B mud slurry. .   In the treatment method according to any one of claims 1 to 7, in the case of treatment of contaminated water, the contaminated water obtained by washing the facility is separated into solid and liquid, and the supernatant water is reused as wash water. , A method for treating an object to be contaminated, wherein the precipitate is supplied as a B mud slurry to the next step. In the processing method according to any one of claims 1 to 8, toxic substances in drainage of B mud slurry is decomposed by the photocatalytic, contaminated object to be treated, characterized in filtration by to Rukoto solids Processing method.   The treatment method according to claim 9, wherein decomposition of harmful substances is performed from a composite oxide phase of an oxide phase (first phase) mainly composed of a silica component and a metal oxide phase (second phase) other than silica. A filter composed of a woven fabric of silica-based composite fiber having a photocatalytic function in which the abundance ratio of at least one constituent component of the second phase is gradually increased toward the surface layer of the fiber, and an ultraviolet lamp. A method for treating an object to be contaminated, which is performed by a purification device provided.

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