JP2011235218A - Method for treating water-containing waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating water containing foul components and other water-containing waste more easily than the prior art.SOLUTION: The method for treating the water-containing waste 1 includes a moisture reducing process for bringing unslaked lime 2 into contact with the water-containing waste 1, and a reclaiming process for reclaiming unslaked lime 2 by heating slaked lime 3 at a temperature not lower than the decomposition temperature of the slaked lime 3 produced by the water absorption reaction of the unslaked lime 2. In the reclaiming process, the slaked lime 3 and a granular heating medium 4 are heated. The granular heating medium may be air-blown in the reclaiming process.

Description

  The present invention relates to a method for treating hydrous waste.

Conventionally, aromatic compounds, organochlorine compounds, pesticides, dioxins, PCBs, waste liquids such as developing waste liquids, incinerator exhaust gas treated water, industrial wastewater, landfill leach wastewater, landfill soil washing wastewater, etc. There has been an application concerning electrochemical oxidative decomposition of a hardly decomposable substance such as a water-soluble polymer such as nitrate ion (Patent Document 1).
In this application, leachable wastewater from landfills after waste treatment, development wastewater, wastewater including chemical factory wastewater, or the above-mentioned hardly decomposable compounds in wastewater have been widely used in the past. In view of the fact that it is difficult to treat sufficiently, the object is to provide a method for electrochemically oxidizing and decomposing waste liquid such as developing waste liquid by electrolysis at a high current density, Waste liquid or waste water containing persistent substances is introduced into the electrolyzer, electrolyzed at a high current density, hypohalous acid and active oxygen are generated in the waste liquid or waste water, giving a strong oxidative decomposition action, and electrolytic treatment Hypohalous acid in water is capable of decomposing with time by contact with organic matter and the like to generate active oxygen such as hydroxy radicals and oxidatively decompose hardly decomposable compounds.
However, there is a problem that the treatment of the waste water by electrolysis (reducing dirt components) is difficult to control.
JP 2003-126860 A

  Therefore, the present invention is intended to provide a method for treating soil component-containing water and other water-containing waste that can be carried out more easily than before.

In order to solve the above problems, the present invention takes the following technical means.
(1) The method for treating hydrous waste according to the present invention comprises a moisture reduction step in which quick lime is brought into contact with the hydrous waste, and the quick lime is regenerated by heating above the decomposition temperature of the slaked lime generated by the quick lime absorbing reaction. And a slaked lime and a granular heating medium are heated in the regeneration step.

Here, as the water-containing waste (which may be mainly “solid” or “water”, etc.), water containing dirt components such as industrial effluents such as chemical factories and liquid crystal manufacturing factories, construction sites And oil-contaminated soil from A heavy oil, kerosene, etc., and its exudate, plum seasoning wastewater (having high COD and high salt concentration), pig manure, chicken manure and other livestock manure, household garbage, first Examples include ketchup and other leftovers from food stores and other restaurants, contaminated blood in hospitals, seafood waste, livestock and other corpses.
Examples of the soil component-containing water component include solvents and other organic compounds (for example, DMSO, DMAc, DMF, MEA), and oil droplets such as A heavy oil and light oil. Moreover, COD, TOC, an n-hexane extract substance, ammonia nitrogen, nitrate nitrogen, etc. can be illustrated as a display parameter | index of the said stain | pollution | contamination component.
The moisture reduction step and the regeneration step may be performed continuously, may be performed independently from each other, or may be performed in parallel as a loop (annular) cycle.

This method for treating hydrous waste has a moisture reduction step in which quick lime is brought into contact with the hydrous waste, so that quick lime absorbs water and chemically changes to slaked lime to generate heat spontaneously <CaO + H ₂ O → Ca (OH ) ₂ +63 kJ / mol>, and in this process, the water content of the quick lime is reduced from the water-containing waste.
In addition, the water-containing waste is reduced by evaporating moisture other than the water absorption reaction of quicklime due to the heat generation. Specifically, quick lime is hydrated and chemically changed to slaked lime in the moisture reduction step, but the moisture of the hydrous waste is evaporated and reduced by this heat of hydration. That is, the spontaneous exothermic reaction when quicklime is hydrated and converted to slaked lime can be used for the evaporation of moisture in the hydrous waste, and the amount of heat required in the regeneration process can be reduced.
In the moisture reduction step, it is preferable in terms of handling and thermal efficiency in the next step to set the mixing amount of the hydrous waste and quick lime so that the water content of the hydrous waste is almost reduced. By using quick lime for the treatment of hydrous waste in this way, make hydrous waste in a dry state (free slaked lime even when water is retained) instead of water treatment (liquid) and make it easier to handle in the next step. Can do.

  And since it has the regeneration process which regenerates quick lime by heating above the decomposition temperature (580 ° C) of slaked lime which the quick lime produced by water absorption reaction, it heats in an aerobic atmosphere to about 580-1000 ° C in this process, for example Then, slaked lime decomposes, combines with oxygen and regenerates to quick lime, and soil components (COD component, TOC component, n-hexane extract, ammonia nitrogen, nitrate nitrogen, etc.) of hydrous waste are thermally decomposed. It can be reduced. Organic substances are almost completely pyrolyzed when heated to 650 ° C or higher (environmental load substances can be decomposed). Thereby, it can contribute to environmental conservation through the zero emission which does not discharge | emit the hydrous waste which is a load with respect to nature.

In this way, the hydrated heat of the quick lime in the moisture reduction process is thermally decomposed by the heat of hydration in the moisture reduction process and the heat in the regeneration process. The amount of heat that is heated during the regeneration of quicklime can be used for the thermal decomposition of soil components, and the soil components can be decomposed by a relatively simple method compared to processes that are complicated to control by electrolysis. it can.
Further, since the slaked lime and the granular heating medium are heated in the regeneration step, the granular heating medium can improve the thermal conductivity with respect to the slaked lime and increase the processing efficiency (reduction of the processing time and the required amount of heat). Reduction).
In addition, quick lime → slaked lime (moisture reduction process), ⇒ slaked lime → quick lime (regeneration process), ⇒ quick lime → slaked lime (moisture reduction process), ⇒ slaked lime → quick lime (regeneration process) ... It can be reused (unlike mere disposable soaking of slaked lime that has absorbed water into acid soil as it is), and drug recycling costs can be reduced by such recycling.

Further, high-concentration water-containing waste (for example, organic wastewater having a COD of 1000 ppm or more) that has been difficult to treat due to the amount of oxidant is not suitable for the electrolysis method. The processing principle of the electrolysis method is an oxidant method, whereas the processing principle of the present invention is a thermal decomposition method.
Here, as described later, when an electrolysis action is used in combination, a very favorable advantage in actual processing that odor can be suppressed occurs.

(2) The granular heating medium may be air blown in the regeneration step.
Constructed in this way, when a granular heating medium (in a heating and regenerative furnace with a heater wound around the outer periphery) is blown, for example, from below, the granular heating medium behaves like a fluidized fluid bed, In the granular heating medium (pseudo) bath, slaked lime is heated by heat transfer from the surrounding heating medium and chemically changed to quick lime. That is, slaked lime can be made excellent in heat transfer efficiency by contact heating with a four-part granular heating medium bath.
When the hydrated waste contains a volatile organic component, the organic component is prevented from moving upward by the obstacle action of the granular heating medium bath layer, and stays in the layer. It will be thermally decomposed during this time, making it difficult for the VOC gas component to leak out. That is, the leakage prevention function of the VOC gas component can be suitably increased by controlling the layer thickness of the granular heating medium bath.

(3) The granular heating medium may have a specific heat smaller than that of air.
An example of the granular heating medium is alumina powder. This alumina (specific heat: 0.19 cal / g · ° C.) has a property that the specific heat is smaller than that of air (specific heat: 0.24 cal / g · ° C.), and it is easier to warm than air and to conduct heat. Therefore, in the regeneration process in which quick lime is regenerated by heating above the decomposition temperature of slaked lime (for example, about 580 to 1000 ° C.), the alumina powder can quickly absorb the ambient temperature and quickly conduct heat to the slaked lime. The specific heat of slaked lime is 0.28.
cal / g · ° C.
If comprised in this way, since it can be excellent in the heat-conduction efficiency to slaked lime in a reproduction | regeneration process, it can be excellent in energy saving and cost saving.

(4) The granular heating medium may have a specific gravity greater than that of quick lime.
An example of the granular heating medium is alumina powder (specific gravity: 3.97). Compared to the specific gravity of 3.97, the bulk specific gravity of quick lime is about 1, and the bulk specific gravity of slaked lime is about 0.5.
If comprised in this way, in the reproduction | regeneration process which heats more than the decomposition temperature of slaked lime (for example, about 580-1000 degreeC) and reproduces quicklime, quicklime is upwards rather than alumina powder by the difference in specific gravity of quicklime and alumina powder. Alumina powder (slaked lime) has a higher specific gravity and is more susceptible to gravity by transferring the heated quick lime to another flow path. It is possible to separate it from that). Then, the separated quicklime is sent again to the moisture reduction step and brought into contact with the hydrous waste.

(5) The hydrous waste may be electrolyzed.
With this configuration, even if the hydrous waste / dirt component-containing water contains a component that emits a bad odor or offensive odor, hypochlorous acid or OH radicals generated due to the electrolysis action Oxidizing power can decompose or reduce or eliminate odor components.
Specifically, when electrolyzed water is added to the water-containing waste or the water-containing waste itself is electrolyzed, the soil components are subdivided and the odor components are decomposed by the oxidizing power of hypochlorous acid and .OH radicals. Therefore, the generation of a strange odor can be suppressed or prevented.

(6) When the alumina powder is blown with air in the regeneration step, the salt is separated from the fluidized bed of the alumina powder.
In other words, alumina has a melting point of 2054 ° C and a boiling point of 3000 ° C, whereas sodium chloride has a melting point of 801 ° C and a boiling point of 1514 ° C. Therefore, alumina powder is solid (particles) in the temperature range of 801 to 1000 ° C. On the other hand, the salt is in a molten liquid state, and the liquid salt can be separated by flowing downward, so that the salt in the hydrous waste can be desalted. The desalted salt can be reused (conducting conductivity to the water to be treated) during electrolysis.

(7) When the alumina powder is air blown in the regeneration step, the metals are separated from the fluidized bed of the alumina powder.
That is, the specific gravity of iron oxide is around 5 and the manganese oxide is 4.5, both of which are larger than 3.97 of alumina, so that in the regeneration process, it moves downward due to the weight difference in the fluidized bed of alumina powder. The specific gravity of sodium chloride is 2.17, which is smaller than that of alumina. However, since sodium chloride is in a molten fluid state in the temperature range of 801 to 1000 ° C, it flows down the fluid bed of alumina powder downward as described above. Will go.

(8) A microwave heating process for evaporating the moisture of the slaked lime generated in the moisture reduction process may be provided, and then the process may be shifted to a regeneration process.
The microwave heating is the principle of a microwave oven, and can be absorbed by irradiating water with, for example, 2.45 GHz microwave, and heated and evaporated (microwave drying). Thereby, the heating energy in the regeneration process can be reduced and the cost can be saved.

(9) An absorbent carrier may be brought into contact with the hydrous waste.
Examples of the absorbent carrier include activated carbon (having adsorptivity), bentonite (having water absorption), and vegetable fiber waste (having water absorption with wood waste, sawdust, etc.), and examples thereof include dirt such as oil droplets. It can absorb and absorb ingredients and moisture. And quick lime can be allowed to bear the function of evaporating initial moisture by the action of generating heat of hydration, and the absorption carrier can be given a function of adsorbing dirt components.
Here, the absorbed bentonite and plant fiber waste are restored to the original dry state when heated to a temperature range of 580 to 1000 ° C. in the regeneration step.

(10) The water content of the hydrous waste material may be separated during or after the water content reduction step, and the inorganic material dissolved in the water content may be reused. Examples of the inorganic material include sodium chloride.
If comprised in this way, a water-containing waste, for example, a soil component containing water, for example, a plum seasoning processing waste liquid, is a high COD (for example, 100,000 to 200,000 ppm or more) and a high salt concentration (for example, 1 to 20% or more). ), But by separating the slaked lime and solids and moisture with a membrane, for example, it is possible to separate the inorganic components dissolved in the moisture, and extract the salt contained in the ume seasoning processing waste liquid as high-concentration water can do. By electrolyzing this high-concentration saline, for example, functional water containing hypochlorous acid (which can be used as the electrolyzed water or other water treatment) can be obtained.

(11) The present invention has the following other features.
(1) Dry treatment In the present invention, since the moisture reduction process applies quick lime to the water-containing waste to reduce the water, the water-containing waste can be brought into a dry state instead of wet. It is easy to remove, can reduce the volume of hydrous waste, and is less likely to generate odor.
In the moisture reduction step, the mixture can be treated so as to be in an anhydrous or nearly anhydrous state by adjusting the mixing ratio of the hydrous waste and quicklime.

(2) Mixing ratio of quick lime and hydrous waste When adjusting the molar ratio of quick lime and hydrous waste to 1: 1, calcium oxide (quick lime) and water (in hydrous waste) The water content is chemically changed to calcium hydroxide (slaked lime), but the water evaporates due to the generation of a large heat of reaction (heat of hydration) during the chemical change. It is preferable to set more than 1: 1. In other words, it is possible to treat a hydrous waste containing water with a molar ratio of 1: 1 or more with quicklime.
The mixing ratio of the quicklime and the hydrous waste is preferably adjusted in anticipation of the calorific value at the time of chemical reaction (= at the time of treatment in the moisture reduction step). For example, by adjusting the amount of hydrous waste to quick lime so that the degree of heat generation in the moisture reduction process is about 100 ° C, the amount of quick lime added (necessary amount) has an excellent cost balance against the evaporation and reduction of moisture. Can be.

(3) Treatment of dirty components in high-concentration wastewater When the water-containing waste (in the case of “water” as the main component) contains a large amount of dirty components (for example, organic ingredients such as seasonings and solvents in the food industry), COD However, wastewater (such as ume seasoning wastewater, etc.) with a concentration of 100,000 to 200,000 ppm is too high to be treated by electrolysis, which makes it extremely difficult (COD does not decrease sufficiently). Reduces moisture by using the quick lime hydration property (absorbs moisture) and heat of hydration (evaporates moisture), and calcines in the regeneration process (heats above the decomposition temperature of slaked lime to change the properties of the substance) ) So that it can be processed even when the content ratio of the dirt component is high, and delicate electrical control as in the case of electrolysis (current value control, voltage value control, water to be treated) Relatively simple without the need for flow rate management or pH management) In addition, the COD components are all oxidized and decomposed because they are exposed to high temperatures (eg, 700 ° C or higher) above the decomposition temperature of slaked lime (melting point 580 ° C) in the regeneration process. Of these, organic components are thought to be almost completely oxidized and converted to carbon dioxide and water.
In this way, it is unthinkable that COD components are almost completely treated even with high-concentration wastewater, and when combined with liquefying and regenerating the water evaporated in the moisture reduction process, It can be converted to highly clean water. That is, it is possible to process and regenerate a wide range of objects from high-concentration wastewater / waste liquid / drainage liquid to low-concentration wastewater with a high dirt evaluation index such as COD by simple procedures.

(4) Processing of noodles such as udon and soba noodles and other boiled soups Noodles such as udon and soba noodles and other unboiled soups contain starch powder (organic matter) and have a high COD value. However, the environmental load caused by the restaurant discharging the waste juice into rivers and sewage has become a problem, but if waste juice containing pieces of udon is treated as hydrous waste, it is dehydrated after the moisture reduction step. Thus, slaked lime and starch are mixed, and when this is baked to, for example, 700 ° C. or higher in the regeneration process, it is not necessary to discharge the river and the environmental load can be reduced.

(5) Processing of squeezed residue such as shochu and salt-added alcoholic beverages Although the squeezed residue discharged in large quantities during the manufacture of shochu was used for land reclamation, it may cause fluidity problems of the ground due to its ruggedness. It was. In addition, waste alcoholic beverages and returned alcoholic beverages that have been discontinued are subject to a problem of how to treat the salt-added alcoholic beverage when liquor tax is refunded if a large amount of salt is added to make it impossible to drink.
So, if this shochu squeezed or salt-added alcoholic beverage is treated as a hydrous waste, it will be dehydrated and dealcoholized after the moisture reduction step, resulting in a mixture of slaked lime and fiber or salt, etc. By firing to 700 ° C or higher, there is no need for land reclamation or river discharge, and the environmental burden can be reduced.

(6) Disposal of mayonnaise, ketchup and other waste A large amount of mayonnaise, ketchup, ice cream, soft cream, dressing, etc. is produced at fast food restaurants and restaurants, but if these are treated as hydrous waste It is dehydrated after the moisture reduction process and becomes a state where slaked lime and fats and oils are mixed, and when this is baked to, for example, 700 ° C. or more in the regeneration process, the fats and oils burn and function as fuel by using this residual heat as waste heat. it can.

(7) Treatment of circulating water in the scrubber The algae grow in the circulating water in the scrubber and a bad odor is generated over time. If this waste circulating water is treated as a hydrous waste, Dehydrated and mixed with slaked lime and algae plant fibers, which are baked in a regeneration step, for example, at 700 ° C. or higher, and the water evaporated in the moisture reduction step is collected, liquefied and reused.

(8) Treatment in the case of “solids” as the main ingredient Okara, which is the remaining rice cake made by squeezing soymilk in the tofu production process, is a health food rich in dietary fiber, calcium, protein, carbohydrates, and potassium. The current situation is that most of the waste is disposed as industrial waste because the quality deteriorates quickly and does not last long. When this okara is treated as water-containing waste, it is dehydrated after the moisture reduction process and mixed with slaked lime. When this is baked in the regeneration process, for example, at 700 ° C or higher, the fiber components and the like are combusted, and this residual heat is used as waste heat. By doing so, it can function as a fuel. In addition, this eliminates the need for disposal as industrial waste, and can contribute to environmental conservation through zero emissions.

(9) Treatment of waste paint liquid If waste liquid with a high solid content, such as paint waste liquid, is treated as hydrous waste, it is dehydrated after the moisture reduction process and mixed with slaked lime and organic components. When this is baked in a regeneration process at, for example, 700 ° C. or higher, the organic component or the like is burned, and can be used as a combustion aid.

(10) Treatment of livestock feces / animal feces When the hydrous waste is low in water content such as livestock feces such as pig feces, chicken feces, cattle feces, and animal feces in zoos (mainly “solid”) In this case, the water can be absorbed or evaporated in the moisture reduction process to make it dry (no more odor is generated), and in the subsequent regeneration process, the temperature is higher than the decomposition temperature of slaked lime (melting point 580 ° C.) (eg 700 The slaked lime can be regenerated into quick lime while the feces are fired to a state close to ash.

(11) Suppression of propagation of fungi and viruses In the present invention, since the water-containing waste can be dehydrated in the moisture reduction step, the propagation of various fungi in the waste can be suppressed and deodorization and sterilization can be performed.

(12) Treatment of animal carcass When water is added to an animal carcass and cut into a mixer and treated as a hydrous waste, it is dehydrated after the moisture reduction process and mixed with slaked lime, which is then regenerated. For example, baking is performed at 700 ° C. or higher. Since the water-containing waste can be dehydrated in the moisture reduction step, the growth of spoilage fungi in the waste is suppressed, and the waste can be treated without being bothered by odor.

(13) Reuse of reduced water (As described above) The water evaporated in the moisture reduction step can be collected, cooled and liquefied for reuse. In particular, when the amount of treatment is large, such as factory effluent, it is preferable to recycle it as industrial water without being released into the atmosphere.
Specifically, when the wastewater from a liquid crystal manufacturing plant (including organic solvents such as DMSO) is treated in a moisture reduction process and the quality of the water collected and analyzed here is analyzed, it is as clean as distilled water. Was expensive. By further treating this water with a reverse osmosis membrane or the like, it can be regenerated as ultrapure water.

(14) Organic soil components in the regeneration process In the regeneration process, when heated to a high temperature (eg, 700 ° C or higher) above the decomposition temperature (melting point 580 ° C) of slaked lime to regenerate quicklime, it adheres to slaked lime and containers. The organic component derived from the soil component is oxidized to release heat, whereby heating energy can be saved and the soil component is almost completely oxidized and decomposed. Here, the heat generated in the moisture reduction process or the heat in the regeneration process can be used to heat other things.

(15) Treatment of contaminated soil and separation of quick lime Electrolyzed water is applied to contaminated soil such as oil, and the soil components are subdivided or decomposed by the action of hypochlorous acid and .OH radicals. The waste product is sent to the moisture reduction step, and then the quick product and soil components of the soil can be separated as follows for the final product after being treated at, for example, 700 ° C. or higher in the regeneration step.
That is, the bulk specific gravity of the soil is 1.8, whereas the bulk specific gravity of the quick lime is 1.06. Therefore, by utilizing the difference in specific gravity, the difference in fluidity between the two is used to separate the soil and quick lime. . The soil is then backfilled in the soil and the quicklime is reused for the next treatment. Furthermore, even if quicklime is mixed in the soil, it can be used as a soil conditioner.

(16) Separation of slaked lime and inorganic components after moisture reduction step After the moisture reduction step, slaked lime and inorganic components in the soil component can be separated as follows. That is, using the difference between the specific gravity of slaked lime (apparent specific gravity of 0.40 to 0.55) and the density of other inorganic components such as salt (2.16 g / cm ³ ) These can be separated by use, and the salt separated from slaked lime can be reused for electrolysis and the like.

(17) Baking of shells, etc. When the hydrous waste contains calcium carbonate such as shells (oysters, clams, strawberries, etc.), the calcium carbonate (melting point 825 ° C) will be converted to calcium oxide when heated to 900 ° C or higher in the regeneration process. Since it changes chemically (= quicklime), quicklime can be increased from the initial amount. Moreover, it is also possible to intentionally mix a substance containing calcium carbonate such as shells with the hydrous waste.
(18) Treatment of infectious waste such as contaminated blood in hospitals and disposable medical instruments Such hydrous waste can be suitably treated by the dehydration action of quicklime.

The present invention is configured as described above and has the following effects.
Since the dirt component can be decomposed by a relatively simple technique as compared with the treatment by the electrolytic method or the like, it is possible to provide a method for treating hydrous waste that can be performed more easily than in the past.

Embodiments of the present invention will be described below.
As shown in FIG. 1, the method for treating hydrous waste according to this embodiment includes a moisture reduction process in which quick lime 2 is brought into contact with hydrous waste 1 (waste liquid), and slaked lime generated by the quick reaction of quick lime 2. 3 is provided with a regeneration step of regenerating quick lime 2 by heating to a decomposition temperature of 3 or more, and in the regeneration step, the slaked lime 3 and the granular heating medium 4 are heated.
That is, the waste liquid which is the hydrous waste 1 flowing into the waste liquid storage tank 5 is supplied to the screw 6 (rotated by the motor M) by the pump P, mixed with the quicklime 2 in the middle of the screw, and regenerated by heating. It is moved in the direction of the furnace 7 (moisture reduction process) and introduced into the heating and regeneration furnace 7. The slaked lime 3 is heated and regenerated into quick lime 2 in the heating and regeneration furnace 7 (regeneration step), and the regenerated quick lime 2 is led out from above to the separate flow path 9 by the air supplied by the compressor 8. It is transferred to the hopper 10. Further, water vapor and air in the heating and regeneration furnace 7 are discharged from the exhaust port 11 to the outside.
A heater 12 is wound around the outer periphery of the heating and regeneration furnace 7, and a water cooling jacket 15 in which the cooling water 14 circulates through a heat insulating material 13 is externally provided on the outer side thereof. A valve V is provided below the heating regeneration furnace 7 so that iron oxide and other metals and salts separated by the treatment can be discharged into the storage container 16 and discarded.

The hydrous waste 1 (waste liquid) has an electrolysis effect by adding electrolyzed water (not shown), and the soil components are subdivided by the oxidizing power of hypochlorous acid and .OH radicals, and odor components. Will be decomposed, and generation of off-flavors can be suppressed or prevented.
In other words, even if the water-containing waste / dirt-containing water contains a component that generates a strange odor or offensive odor, the odor is generated by the oxidizing power of hypochlorous acid or OH radicals generated due to electrolysis. The components can be decomposed and reduced or eliminated.

Here, as the water-containing waste (which may be mainly “solid” or “water”, etc.), water containing dirt components such as industrial effluents such as chemical factories and liquid crystal manufacturing factories, construction sites And oil-contaminated soil from A heavy oil, kerosene, etc., and its exudate, plum seasoning wastewater (having high COD and high salt concentration), pig manure, chicken manure and other livestock manure, household garbage, first -The leftovers of food restaurants and other restaurants can be exemplified.
Examples of the soil component-containing water component include solvents and other organic compounds (for example, DMSO, DMAc, DMF, MEA), and oil droplets such as A heavy oil and light oil. Moreover, COD, TOC, an n-hexane extract substance, ammonia nitrogen, nitrate nitrogen, etc. can be illustrated as a display parameter | index of the said stain | pollution | contamination component.
The moisture reduction step and the regeneration step are performed in parallel as a loop (annular) cycle.

Next, the use state of the processing method of the hydrous waste of this embodiment is demonstrated.
This method for treating hydrous waste has a moisture reduction step in which quick lime 2 is brought into contact with hydrous waste 1, so quick lime 2 undergoes a water absorption reaction and chemically changes to slaked lime 3 to generate heat spontaneously <CaO + H ₂ O → Ca (OH) ₂ +63 kJ / mol>, and in this process, the water content of the quick lime 2 is reduced from the hydrous waste 1.
In addition, the water-containing waste 1 evaporates and reduces moisture other than the water-absorbing reaction component of the quicklime 2 due to the heat generation. Specifically, the quick lime 2 hydrates and chemically changes to slaked lime 3 in the moisture reduction step, but the moisture of the hydrous waste 1 evaporates and is reduced by this heat of hydration. That is, the spontaneous exothermic reaction when quicklime 2 is hydrated and changed to slaked lime 3 can be used for the evaporation of the moisture of the hydrous waste 1, and the amount of heat required in the regeneration process can be reduced.
Thus, since quick lime 2 was utilized for the treatment of the hydrous waste 1, the hydrous waste 1 is not treated with water (liquid) but in a dry state (slaked lime 3 that is smooth even if the water is retained) and handled in the next step. Can be made easier. Thus, it is preferable in terms of handling and thermal efficiency in the next step to set the mixing amount of the hydrous waste 1 and the quicklime 2 so that the water content of the hydrous waste 1 is almost reduced.

  And since it has the reproduction | regeneration process which regenerates quicklime 2 by heating more than the decomposition temperature (580 degreeC) of the slaked lime 3 which the said quicklime 2 produced | generated by water-absorption reaction, it is an aerobic atmosphere at about 580-1000 degreeC by this process, for example. When heated below, the slaked lime 3 decomposes and combines with oxygen to regenerate quick lime 2, and the soil components (COD component, TOC component, n-hexane extract, ammonia nitrogen, nitrate nitrogen, etc.) of the hydrous waste 1 ) Is reduced by thermal decomposition. In particular, organic substances are almost completely thermally decomposed when heated to 650 ° C. or higher (environmental load substances can be decomposed). Thereby, it can contribute to environmental conservation through the zero emission which does not discharge | emit the hydrous waste 1 which is a load with respect to nature.

In this way, the hydration heat of the quick lime 2 in the moisture reduction step is thermally decomposed by the heat of hydration of the quick lime 2 and the heating in the regeneration step, so The amount of heat heated during the regeneration of quicklime 2 in the regeneration process can be used for the thermal decomposition of the soil components, and the soil components are decomposed by a relatively simple method compared to processes that are complicated to control by electrolysis. And has the advantage that it can be performed more easily than in the prior art.
Further, since the slaked lime 3 and the granular heating medium 4 are heated in the regeneration step, the thermal conductivity with respect to the slaked lime 3 can be improved by the granular heating medium 4 and the processing efficiency can be increased (reduction of processing time). , Reduction of required heat).

In addition, quick lime 2 → slaked lime 3 (moisture reduction process), ⇒ slaked lime 3 → quick lime 2 (regeneration process), ⇒ quick lime 2 → slaked lime 3 (moisture reduction process), ⇒ slaked lime 3 → quick lime 2 (regeneration process), And quick lime 2 can be repeatedly recycled and reused (unlike mere disposable soaking of slaked lime 3 that has drained water as it is in acid soil), and such recycling can reduce drug running costs. it can.
In addition, high-concentration water-containing waste 1 (for example, organic wastewater having a COD of 1000 ppm or more), which has been difficult to process because of the amount of oxidant in the electrolysis method, can be suitably processed. The processing principle of the electrolysis method is an oxidant method, whereas the processing principle of the present invention is a thermal decomposition method.

(2) In the regeneration step, the granular heating medium 4 is air blown as described above. That is, the granular heating medium 4 in the heating / reproducing furnace 7 around which the heater 12 is wound is air blown from below by the compressor 8, and the granular heating medium 4 behaves like a fluidized fluid bed. In other words, in the granular heating medium 4 (pseudo) bath, the slaked lime 3 is subjected to heat transfer from the surrounding heating medium 4 and chemically changed to quick lime 2. That is, the slaked lime 3 can be made excellent in heat transfer efficiency by contact heating with a four-circular granular heating medium 4 bath.
Further, when the hydrated waste 1 contains a volatile organic component, the organic component is prevented from moving upward by the obstacle action of the layer of the granular heating medium bath and stays in the layer. During this time, it is thermally decomposed, and the VOC gas component can be hardly leaked to the outside. That is, the leakage prevention function of the VOC gas component can be suitably increased by controlling the layer thickness of the granular heating medium bath.

(3) The granular heating medium 4 has a specific heat smaller than that of air. Alumina powder was used as the granular heating medium 4. This alumina (specific heat: 0.19 cal / g · ° C.) has a property that the specific heat is smaller than that of air (specific heat: 0.24 cal / g · ° C.), and it is easier to warm than air and to conduct heat. Therefore, in the regeneration process in which quick lime 2 is regenerated by heating to a temperature equal to or higher than the decomposition temperature of slaked lime 3 (for example, about 580 to 1000 ° C.), the alumina powder can quickly absorb the ambient temperature and quickly conduct heat to slaked lime 3. it can. The specific heat of slaked lime 3 is 0.28 cal / g · ° C.
Therefore, in the regeneration process, the heat conduction efficiency to the slaked lime 3 can be excellent, and the energy and cost can be excellent.

(4) The granular heating medium 4 has a specific gravity greater than that of the quicklime 2. Alumina powder (specific gravity: 3.97) was used as the granular heating medium 4. The bulk specific gravity of quick lime 2 is about 1 and the bulk specific gravity of slaked lime 3 is about 0.5 with respect to the specific gravity of 3.97.
Therefore, in the regeneration process in which quick lime 2 is regenerated by heating to a temperature equal to or higher than the decomposition temperature of slaked lime 3 (for example, about 580 to 1000 ° C.), quick lime 2 is positioned above the alumina powder due to the difference in specific gravity between quick lime 2 and alumina powder. It becomes easy to soar (the slaked lime 3 is transferred to quick lime 2 in the process of soaring), and by moving the soared quick lime 2 to another flow path, the specific gravity is more susceptible to the action of gravity. It becomes possible to separate from the powder (which is less likely to rise than the slaked lime 3). And the separated quicklime 2 is sent again to the moisture reduction step and brought into contact with the hydrous waste 1.

(5) In the regeneration step, the alumina powder is air blown as described above, and salt is separated from the fluidized bed of the alumina powder.
In other words, alumina has a melting point of 2054 ° C and a boiling point of 3000 ° C, whereas sodium chloride has a melting point of 801 ° C and a boiling point of 1514 ° C. Therefore, alumina powder is solid (particles) in the temperature range of 801 to 1000 ° C. On the other hand, the salt is in a molten liquid state, and the liquid salt can be separated by flowing down, and the salt in the hydrous waste 1 can be desalted. . The desalted salt can be reused (conducting conductivity to the water to be treated) during electrolysis.

(6) In the regeneration step, the alumina powder is air blown as described above, and the metals are separated from the fluidized bed of the alumina powder.
That is, the specific gravity of iron oxide is around 5 and the manganese oxide is 4.5, both of which are larger than 3.97 of alumina, so that in the regeneration process, it moves downward due to the weight difference in the fluidized bed of alumina powder. The specific gravity of sodium chloride is 2.17, which is smaller than that of alumina. However, since sodium chloride is in a molten fluid state in the temperature range of 801 to 1000 ° C, it flows down the fluid bed of alumina powder downward as described above. Will go.

  Compared with treatments that are complicated to control by electrolysis, dirt components can be decomposed by a relatively simple method and can be carried out more easily than before. It can be applied for use.

The apparatus flow figure explaining embodiment of the processing method of the hydrous waste of this invention.

1 Hydrous waste 2 Quicklime 3 Slaked lime (illustrated with smaller grains for comparison)
4 Heating medium (shown as comparatively larger grains)

Claims (5)

  A moisture reduction step of bringing quick lime 2 into contact with hydrous waste 1 and a regeneration step of regenerating quick lime 2 by heating to a temperature higher than the decomposition temperature of slaked lime 3 generated by the quick lime 2 absorbing water, and the regeneration A method for treating hydrous waste, wherein the slaked lime 3 and the granular heating medium 4 are heated in the process.   The method for treating hydrous waste according to claim 1, wherein the granular heating medium (4) is air blown in the regeneration step.   The method for treating hydrous waste according to claim 1 or 2, wherein the granular heating medium 4 has a specific heat smaller than that of air.   The method for treating hydrous waste according to any one of claims 1 to 3, wherein the granular heating medium 4 has a specific gravity greater than that of quicklime.   The method for treating hydrous waste according to any one of claims 1 to 4, wherein the hydrous waste 1 is electrolyzed.