JPH0325233B2 - - Google Patents

Description

[Detailed description of the invention]

[Detailed Description of the Invention] The present invention is applicable to sewage, human waste, slaughterhouse wastewater, livestock wastewater,
Fishery processing wastewater, starch wastewater, alcoholic wastewater, pharmaceutical manufacturing wastewater, heavy metal-containing wastewater, tannery wastewater, dyeing wastewater, plating wastewater, oil-containing wastewater, hospital wastewater, electrical machinery factory wastewater,
Regarding a method for treating polluted water that can extremely easily and effectively deodorize and purify wastewater that is a source of environmental pollution, such as garbage processing wastewater, food processing wastewater, and domestic gray water, even in its original concentration state, in more detail, The present invention relates to a method for treating polluted water that can achieve the above effects using Conventionally, in the treatment of various types of concentrated polluted water and malodorous sludge, large amounts of diluted water are used, requiring large processing capacity equipment, resulting in problems such as excessive equipment costs, poor management and maintenance, and problems during the treatment process. There are problems such as odor generation and the huge cost required for final treatment (heavy oil incineration, cement consolidation, dumping, etc.). For example, in the case of a city sewage system of 200,000 people, if treated using the activated sludge method, the amount of sludge generated would be approximately 200 ^m3 per day with SS (solid content) of 250,000 ppm. , the total running cost exceeds 5,000 yen per ^1m3 , which means an expense of more than 1 million yen per day.
Moreover, the negative effects of secondary pollution still remain. The present inventor has discovered that when a combination of particle size-adjusted pulverized coal, granular carbon, and iron-aluminum flocculant is added to polluted water and sludge for treatment, the organic It was discovered that aggregates of inorganic impurities are formed and separated by sedimentation, and purified water can be easily obtained as supernatant water (Tokuko Sho
54-36413). In such cases, it is extremely easy to separate the sedimented and separated carbon-containing aggregates, and in the continuous dehydration process, the pulverized coal coarse particles are self-precoated on the cloth, and a low negative pressure (200 mmHg) is applied.
Extremely large overspeed (40
Kg/m ² h) (the overspeed of a general-purpose dehydrator is 2 to 20 Kg/m ² h), high efficiency makes dewatering possible, and the resulting dehydrated cake has a high water content. It has the advantage over conventional methods that it can be used as an odorless fuel or fertilizer immediately after being naturally dried and subjected to secondary dehydration by taking advantage of the water repellency of coal. Based on such technical knowledge, the present inventor further conducted research on methods for effectively treating various types of polluted water and sludge, and found that unused fueling stone, in which coal is naturally coked underground under high temperature and high pressure, It has been discovered that if the pulverized coal is pulverized and its particle size is adjusted and used alone or in combination with the pulverized coal described in the above publication, the same or greater effect can be obtained than when the pulverized coal is used alone. Ta. Incidentally, fanning stone refers to coal that has been carbonized and altered by the heat of volcanic rock that has penetrated into the underground coal seam or near the upper and lower beds, and this rock has a higher ash content than ordinary anthracite or coke. Also, the mixture of non-uniform materials makes it difficult to use, and many are left unused underground. Unfortunately, it is said that hundreds of millions of tons of fueling stones are found in Japan's coal reserves. That is, an object of the present invention is to provide a method for treating polluted water that effectively and economically utilizes a large amount of unused fanning stones left underground. According to the present invention, (a) particle size-adjusted pulverized coal containing 10% by weight or more of fanning stone powder and 85% by weight or more of particle size 6 to 500 mesh; (b) hydroxylated by hydrolysis; A method for treating polluted water by combining a flocculant capable of forming iron hydroxide with aluminum or aluminum hydroxide, and, if necessary, (c) a PH neutralization regulator, comprising: adding the above to the polluted water prior to adding the Particle size controlled pulverized coal
An aqueous suspension containing (a) at a concentration of 5 to 20% by weight is vigorously stirred without substantially destroying the particle size, and then this treated suspension is added to the polluted water along with other ingredients. A method for treating polluted water is provided. The particle size-adjusted pulverized coal of component (a) used in the method of the present invention includes low-grade precipitated pulverized coal produced as a by-product in the coal preparation process of coal mines, and granulated coal of coals such as low carbonization lignite, lignite, and peat. It contains 10% by weight or more of agitation powder, particularly in the range of 20 to 50% by weight, and may be 100% agitation powder depending on the properties of the polluted water. Particle size is adjusted to 500 mesh. In the present invention, unless the fanning stone powder is used alone as component (a), the fanning stone powder is used in combination with other pulverized coal. Although the particle size of pulverized coal may be adjusted, the relatively low-grade pulverized coal mentioned above is advantageously used industrially. In addition, low-grade coal with a low product position that is considered to be below grade coal for sale, e.g.
High ash content coal having a calorific value of 3500 Kcal/Kg to 5000 Kcal/Kg can also be used advantageously by adjusting the particle size, and low-rank coal is rather welcomed in the present invention. The size-adjusted pulverized coal used as component (a) in the present invention must have a particle size in the range of 6 to 500 meshes in an amount of 85% by weight or more. Coarse particles that cannot pass through a 6-mesh sieve undergo sedimentation more rapidly than necessary, resulting in insufficient adsorption and flocculation with the sludge, while extremely fine particles that pass through a 500-mesh sieve do not flocculate. This is because the settling time will be significantly longer even if the temperature is lowered. An important feature of the present invention is the use of particle size-adjusted pulverized coal containing 10% by weight or more of fanning stone powder. The fan stones used in the present invention are classified into three types: hashiri, okori (smokeless), and chikura, depending on the degree of alteration or form of volcanic rock.
Both are more porous than ordinary pulverized coal and have a higher specific gravity. In the present invention, any of the above-mentioned fan stones can be used; for example, Okoli generally has a fixed carbon content of 75-85%, a volatile content of 3-6.5%, and a true specific gravity of 1.5.
~1.9, and therefore, even if it is made into fine powder, aggregates of pollutant components in polluted water can be separated and settled easily because of their high specific gravity and because the fan stone powder is porous. Therefore, the removal of contaminant components is carried out effectively. This component (a), particle size-adjusted pulverized coal, has a weight of 20 to 300% relative to the BOD component (dry weight equivalent) or SS component (solid content, dry weight equivalent) of the polluted water, although this varies depending on the properties of the polluted water. %, particularly in the range of 50 to 100% by weight. In the present invention, the particle size-adjusted pulverized coal (a) described above is mixed with 5 to 20% of the component (a) before adding other components.
An aqueous suspension containing a concentration of % by weight is vigorously stirred under conditions that do not substantially destroy the particle size, and then added to polluted water. By carrying out such stirring treatment, the purification effects such as adsorption, coagulation, sedimentation, and separation of contaminants can be further improved, and the amount of treatment agent used can be significantly reduced. In the present invention, stirring of the particle size-adjusted pulverized coal slurry is difficult to obtain an effect at a concentration lower than 5% by weight, and when the concentration is higher than 20% by weight, it is difficult to form a slurry. This results in the inconvenience of being easily destroyed. Furthermore, it is necessary to stir the slurry using a multi-blade stirrer at a rotational speed of at least 300 rpm. A speed of less than 300 rpm is not completely ineffective, but a speed of 300 rpm or higher is preferable. However, if the rotation speed is too high, not only will the fan stone powder and pulverized coal be finely divided, but it will also not be easy to operate, and the equipment will require high strength, so a speed of up to about 1000 rpm is advantageously adopted. In addition, since the fanning stone powder mixed in component (a) used in the present invention has a high specific gravity, stirring with only a stirrer will cause the stirring stone powder to settle at the bottom of the suspension tank. For example, it is desirable to blow compressed air to assist the stirring. In this way, particle size-adjusted pulverized coal (a) in which the fanning stone powder is uniformly dispersed is prepared. In the present invention, prior to adding component (a) to polluted water, stirring and friction treatment is performed in the aqueous suspension to increase the adsorption ability and flocculation ability of solid content and COD components. This makes it possible to reduce the amount of agitating stone powder and pulverized coal used for particle size adjustment to about half. In general, the particles of pulverized coal (a) whose particle size is adjusted adsorb various gaseous substances, and the voids (pores)
contains air, but when the aqueous suspension is stirred prior to use, these gaseous substances and air are removed by the water, resulting in the particle surface coming into contact with the components to be removed in the polluted water. Not only is the efficiency significantly improved, but also a stable and uniform water film is formed on the particle surface, and a so-called electric double layer is stably formed around the particle, that is, the zeta potential of the particle is increased. This also promotes electrophoretic adsorption of solids in polluted water. Thus, by performing a strong stirring treatment prior to addition to polluted water, adsorption ability and flocculation ability can be significantly increased. Further, in the present invention, a flocculant capable of forming aluminum hydroxide or aluminum hydroxide and iron hydroxide by hydrolysis is used as component (b). The flocculant of component (b) is known as an inorganic flocculant, and includes, for example, aluminum sulfate, aluminum sulfate-iron sulfate complex, sodium aluminate, aluminum alum, or red mud treated with sulfuric acid. In the present invention, red mud waste from aluminum smelting is sulfurized (Special Publication No. 50-27946).
(see Japanese Patent Application Publication No. 2003-110001) can be used industrially with particular advantage. Component (b) used in the method of the present invention is usually used in an amount of about 10 to 50% by weight, particularly 15 to 40% by weight, based on the total weight of components (a) and (b).
If the amount is less than the above range, the floc will become brittle, thereby increasing the elapsed time. Moreover, even if it is used in an amount larger than the above range, the effect cannot be enhanced, which is economically disadvantageous. however,
The above-mentioned amount of component (b) to be used can be selected depending on the condition of the polluted liquid, etc., and is not necessarily critical. In addition, known inorganic flocculants other than component (b), such as silica sol, stannic acid sol, sulfur hydrosol, iron sulfate, and chlorinated green bean, can be used in combination. Furthermore, in the present invention, component (c) is used for the purpose of pH adjustment, if necessary. For example, if the polluted liquid is acidic, the effects of the present invention can often be further enhanced by neutralizing it with an alkali agent. In such a case, the alkaline agent used as component (c) includes hydroxides and carbonates of alkali metals and alkaline earth metals, and salts of other inorganic weak acids and organic acids, and one or two types thereof may be used. The above are used together. In addition, in the treatment method of the present invention, the above (a) to
Although each component (c) is combined to treat polluted water, the effect can be further improved by further combined use of an organic polymer flocculant or flocculation aid. Examples of such flocculants include commonly known anionic, cationic, or nonionic polymer flocculants such as polyacrylic acid, polymethacrylic acid, CMC, sodium alginate, starch, soaps, gelatin, or albumin, especially anionic polymer flocculants. These organic polymers may be used singly or in combination.
More than one species can be used in combination. These vary depending on the condition of the polluted water to be treated, but are usually 0.1
The amount used may be less than 0.01% by weight, for example, 0.01% by weight.
Addition of extremely small amounts (100 ppm or less) is often sufficient. Further, in the present invention, extremely fine carbon particles having an average particle diameter of about 100 mμ can be used in combination with component (a), either in a suspended form or separately. This fine particulate carbon adsorbs impurity components (pollutant components) of the polluted liquid and forms strong re-agglomerates with the particles of component (a).Thus, during excessive suction, the pollutant components pass through the cloth and become liquid. In addition to preventing the inconvenience of contaminating the liquid, this fine particulate carbon has extremely excellent decolorizing performance against polluted liquid. Such carbon is suitably naphtha carbon or oil carbon. For example, since naphtha carbon is a surplus by-produced in the cracking process of naphtha, it is extremely advantageous to be able to utilize it conveniently. It is generally desirable to use this carbon in a range of 5 to 20% by weight based on the size-adjusted pulverized coal of component (a), but this varies depending on the condition of the polluted liquid and is not necessarily critical. Furthermore, when the carbon-containing sludge dehydrated cake that is finally captured is used as fertilizer, it is desirable that the content be 10% by weight or less. In addition, in the present invention, when adding the aqueous suspension of component (a) to the polluted liquid, a known oxidizing agent such as potassium hypochlorite or enzyme-containing humus (see Patent No. 1061725) is added. It is also possible to shorten the reaction time by using them together. Components (b) and (c) used in the present invention may be used in a dry state, or may be added in a suspension or wet state, and may be added to polluted water separately or after being mixed in advance. be able to. In the treatment method of the present invention, after the above-mentioned treatment agent is added and mixed, adsorption, aggregation, and sedimentation occur in a very short period of time, and a highly purified supernatant liquid is obtained, and the sediment is further separated using a cloth or the like. It is also extremely easy to process, and a continuous processing method can be advantageously adopted. The present invention, which can continuously treat various types of wastewater and sludge that are normally discharged in large quantities, and can achieve satisfactory effects with the use of a relatively small amount of treatment agent, is extremely meaningful industrially and welcomed by society. This is a practical invention that should be done. In addition, each processing agent component is a surplus by-product or a substance with a low commercial value, and in this respect as well, the present invention has great social value. When continuous treatment is carried out in the treatment of the present invention, it is preferable that the particle size-adjusted pulverized coal component (a) is continuously stirred in an aqueous medium, but a batch method is also sufficient. Continuous treatment includes, for example, a mixing tank in which polluted liquid and additive processing agents are continuously charged and mixed by stirring, a solid-liquid separation tank into which the mixture is continuously injected from the mixing tank through a conduit, and a continuous process from the bottom of the tank. This can be carried out in combination with a continuous filtration device that separates the liquid of coagulated precipitate that is extracted and led through a conduit. It is desirable that the mixing tank is equipped with a stirrer to sufficiently mix the pollutant liquid and the treatment agent, and the separation tank should be equipped with a stirrer so that the supernatant liquid overflows and the overflow part and the coagulation sedimentation part at the bottom are not disturbed. It is desirable that the introduction of liquid be designed. Furthermore, as a continuous filtration device, it is easy to separate the aggregates, so for example, a cloth is used as an endless belt, the direction of movement of which is tilted upward, and a liquid reservoir is formed on the lower side of the front side to receive the mixed liquid. A side plate is provided so that a precoat layer is formed and the precipitated coagulated sediment is transferred upward, while the temperature is normally 100 to 200 mmHg from the back side after the liquid reservoir.
It is convenient to use one designed to dehydrate by reducing the pressure to a certain level of negative pressure. The moisture content of the resulting cake is easily less than 50%, and in the above-mentioned filtration device, when the cloth is turned by the upper conveyor roll, it falls downward, so that the cake can be conveniently collected. The low moisture content cake obtained by the treatment method of the present invention can easily have a moisture content of 30% or less by natural air drying for 2 to 4 days, and they usually have a moisture content of 30% or less.
Since it has a calorific value of 3500Kcal/Kg to 5000Kcal/Kg, it is extremely convenient because it can be directly incinerated or subjected to high-heat drying treatment without requiring auxiliary fuel. Furthermore, if the raw solution to be treated contains harmless fertilizer components, the cake can also be used as a land conditioner or fertilizer. In addition, in the present invention, the treated water is treated by electrolytically filtering the separated supernatant water in which the pollutant components in the polluted water have been coagulated and precipitated in an electrolytic layer having an anode or a cathode in a fine grain layer of fan stones with a particle size of 16 to 3 mesh. It becomes possible to further purify the water quality. Conventionally, electrostatic induction adsorption tanks using activated carbon as a superagent have been known, but as is well known, activated carbon is expensive and its industrial use is therefore economically disadvantageous. Furthermore, even if used activated carbon is reused, a large amount of expense is required for the regeneration equipment, etc., and economic disadvantages cannot be avoided. On the other hand, in the above aspect of the present invention,
As mentioned above, the fanning stone used as a tank is
In particular, in Japan, hundreds of millions of tons are left unused, and even in currently operating coal mines, a huge amount remains in the existing tunnels, and can be obtained at a very low cost, making it economically viable. It brings significant benefits in many ways. In FIG. 1 showing an embodiment of the electrolytic cell used in the above-mentioned embodiment of the present invention, the electrolytic cell 1 is equipped with an inner cylinder 4 having an outer circumferential wall 2 and a fine grain layer 3 therein. This fanning stone fine grain layer 3 is provided with an anode connected to the terminal of the slide rack S, and a wire mesh 5 is provided along the inside of the outer peripheral wall 2, and this wire mesh 5 is connected to the terminal of the slide rack S. It functions as a cathode. The fine-grained rock layer 3 is made of fine coal having a grain size of 16 to 3 mesh and containing 50% by weight or more of fine grained rock. If the particle size of the pulverized coal is larger than the above range, the removal of impurities will not be sufficient, and if it is smaller than the above range, the overspeed will be small and the overefficiency will be unsatisfactory. Furthermore, if the content of the fine powder is less than the above range, the removal of impurities during the process will not be sufficient. This is thought to be because fanstone was metamorphosed into a more porous pore structure than coal during its natural generation period. That is, in this embodiment, the separated supernatant water in which the pollutant components in the polluted water have been coagulated and settled is introduced from the upper opening of the inner cylinder 4, and is made to pass through the fan stone fine grain layer 3 to which a bias voltage is applied by the slider S. . However, since the fine coal particles in the fan stone fine grain layer 3 are each positively or negatively charged, the dissolved impurities in the treated water are electrochemically decomposed and adsorbed to each fine coal particle. The treated water thus filtered is recovered through the outlet opening 6. In addition, in this embodiment, when the pulverized coal particles reach adsorption saturation, the adsorbed substances can be easily desorbed by switching the electric field, applying a bias voltage, and washing with water, making it possible to reuse them. It is. Further, even if this fanning stone fine grain layer is simply applied as a superagent, good results can be obtained as shown in Example 2 described later. As mentioned above, in the method for treating polluted liquid according to the present invention, by using particle size-adjusted pulverized coal containing agitation stone powder in combination with other treatment agents,
The reaction is completed within a very short time, and adsorption, coagulation, and sedimentation separation are carried out, and if necessary, the purified supernatant water is purified using simple filtration or filtration using fine coal particles containing agitator fine powder as a filter. Highly purified water can be obtained by applying electrolysis. In addition, the separated sediment is rapidly consolidated and discharged from the bottom of the solid-liquid separation tank, and then the continuous filtration device (Patent No. 942147,
808330), it is possible to obtain a carbon-containing sludge dewatered cake with a low moisture content (50% or less) under low negative pressure and high yield. In this case, the water repellency is further increased by using the agitation powder, and the peeling of the dehydrated cake from the cloth becomes even better. A further noteworthy advantage of the present invention is that when the carbon-containing dehydrated cake is converted into fuel, it becomes an odorless, smokeless, and high calorific value fuel. In this case, the reason why the explosion phenomenon, which is considered to be the biggest drawback of the fan stone, does not occur at all is because
It is thought that by forming the powder into a fine powder (6 to 500 mesh), most of the contained water escapes and that it undergoes phase change and decomposition during the reaction process with the polluted liquid. Another disadvantage of fanning stones as a fuel is that they have a high ignition temperature (440 to 600°C), but this is also true of ordinary pulverized coal that does not contain fanning stones (see Patent No. 1000155). , ignition temperature 320
(~400°C), it ignites at a relatively low temperature even when used as fuel pellets or briquettes. Furthermore, when the pulverized coal particles containing fanning stones used as a surcharge agent reach adsorption saturation, they can be reused as particle size-adjusted pulverized coal of component (a) by being crushed to a predetermined particle size using a pulverizer. The invention is illustrated by the following example. Example 1 100% and 50% fanning stone powder from Mitsubishi Takashima Coal Mine, respectively.
% and 0% particle size adjusted pulverized coal A, B, and C, and according to the recipe shown in Table 1 below, the COD was
Treated plating factory waste liquid with a concentration of 1900ppm. Table 1 shows the COD removal rate, precipitation rate, and color tone of the treated water. Incidentally, 90% of particle size-adjusted pulverized coals A, B, and C all have particle sizes of 16 to 325 mesh. In addition, the sedimentation rate (SV) is calculated by the following formula from the height h ₁ of the supernatant liquid layer and the height h ₀ of the sedimentation layer after 30 minutes after adding the treatment agent to the liquid to be treated and stirring. Ru. SV = h ₀ / h ₁ + h ₀ × 100 (%) The particle size-adjusted pulverized coal has a suspension of approximately 25%, and is mixed with a multi-blade mixer at a rotation speed of 300 rpm. The mixture was stirred for 30 minutes while blowing air through the tube, and then added to the treatment solution.

[Table] Example 2 Agitation stone powder alone (A), particle size-adjusted pulverized coal containing 50% agitation stone powder (B), Tenboku charcoal processed granule size-adjusted pulverized coal containing 0% agitation stone powder (C), and granular activated carbon (D) ), the activated sludge method-treated domestic wastewater (COD is 78 ppm) was subjected to simple filtration and electrolytic filtration using the filter device shown in Figure 1.
The results are shown in Table 2. In addition, both simple overspeed and electrolytic overspeed
2.7 m ³ /m ² ·hr, and the residence contact time was about 10 minutes.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a diagram showing an electrolysis tank used in one embodiment of the present invention. 1 is an overtank, 2 is an outer wall, 3 is a rock fine grain layer, 4 is an inner cylinder, 5 is a wire mesh, 6 is an outlet opening, and S is a slider.

Claims (1)

[Scope of Claims] 1 (a) Particle size-adjusted pulverized coal containing 10% by weight or more of fanning stone powder and 85% by weight or more of particle size 6 to 500 mesh; (b) Water produced by hydrolysis. a flocculant capable of forming iron hydroxide with aluminum oxide or aluminum hydroxide; and, if necessary, (c) a PH neutralizing agent. The above particle size adjusted pulverized coal
An aqueous suspension containing (a) at a concentration of 5 to 20% by weight is vigorously stirred without substantially destroying the particle size, and then this treated suspension is added to the polluted water along with other ingredients. A method for treating polluted water characterized by the following.