JP2001347104A - Powdery decontaminant and method of decontaminating clean water and waste water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decontaminant for clean water and waste water, which is capable of obtaining excellent result about any of the forming property, the precipitation velocity and the filtration property of floc, the water content and the treating time of a filter cake, the removing property of dissolved metals and the pH value of treated water. SOLUTION: The powdery decontaminant contains fly ash and sodium carbonate as flocaulation main agents and if needed, other well-known inorganic flocculant and/or organic flocculant, a pH adjuster and assistant agents such as activated silica, clay and clinker ash.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powdery purification agent for treating tap water, or for purifying waste water such as sewage, industrial waste water, or polluted waste water from construction sites, and water or waste water using the purification agent. A purification treatment method. More specifically, the present invention relates to water to be treated, which is treated water or waste water, regardless of whether it is organic or inorganic, and pollutants are dissolved or suspended in the treated water. Both can be sedimented and separated at the same time, i.e., dissolved pollutants such as heavy metal ions and suspended suspended materials can be sedimented and separated at the same time. The present invention relates to a purification agent and a purification method for clean water and waste water capable of converting treated water into treated water having excellent water quality.

[0002]

2. Description of the Related Art Conventionally, in order to treat clean water, to treat industrial wastewater such as wastewater and wastewater from factories, and to treat polluted water such as sewage wastewater from homes, etc. A method has been adopted in which an agent is charged to agglomerate suspended substances in water to form sludge (sludge), and then the sludge is separated from water. Furthermore, in the case of wastewater treatment, the treated water is discharged after, for example, pH adjustment so as to satisfy a predetermined water quality standard, while the separated sludge is dewatered, solidified, and discarded.

At this time, as a flocculant for treating the polluted water to flocculate the suspended substance, an inorganic flocculant represented by a sulfate band, polyaluminum chloride, or the like, or a natural or synthetic polymer flocculant is used. Widely known. For example, as a typical wastewater treatment, an inorganic flocculant such as a sulfuric acid band is used as a flocculant, and this is poured into wastewater to adjust the pH and further, if necessary, a natural or synthetic polymer flocculant which is dissolved in a liquid state. There is known a method of injecting and stirring to separate pollutants from the wastewater as flocs. In this method, since the flocculant is used as an aqueous solution at the time of addition, the amount of addition can be controlled relatively accurately even with a small amount, but on the other hand, the labor required for dissolution and the complexity of using various chemicals are increased. There is. In particular,
Polymer flocculants are often dissolved and used on site,
It takes time and effort for adjustment.

In order to improve the complexity of wastewater treatment using such a flocculant, and to perform good and quick purification treatment, various studies have hitherto been made. That is,
Such studies include the development of new flocculants and adjuvants that are compatible with conventional processing methods, the development of new processing methods, and improvements in processing conditions in conventional processing methods. And as a new treatment agent or treatment method,
For example, as a means for increasing the agglomeration rate or improving the dehydration of generated floc, in addition to the conventional aggregating agent, a method of adding diatomaceous earth, clay, gypsum, limes, calcium carbonate, etc. as an auxiliary agent or fly ash Various methods have been reported, for example, a method of adding a coagulant (JP-A-49-79978) or the development of a flocculant composition having a pH adjusting function also intended to improve the wastewater treatment step.

[0005] However, in the conventional method for treating polluted wastewater, the main purpose is to effectively flocculate suspended substances in the wastewater regardless of whether the flocculant is an inorganic flocculant or an organic flocculant. The purpose is set. Therefore, when a coagulant is introduced into wastewater in which metals such as Fe, Cr, Pb, and Cd are dissolved as ions or complexes, for example, some of these metals are separated in a state surrounded by sludge. However, there is a problem that dissolved substances such as metals cannot be removed effectively because the fed flocculant itself does not have the ability to fix and separate these metals. For this reason, in the conventional wastewater treatment, there is also a problem that it may be necessary to use another treatment system in combination in order to remove dissolved substances such as metals in the wastewater.

[0006] Separated sludge obtained by conventional wastewater treatment is generally easily soluble in water. Therefore, when the separated polluted wastewater contains the above-mentioned metals and the like, these dissolved substances may be re-eluted from the separated sludge to cause new environmental pollution.

In order to solve such a problem, suspended substances in polluted wastewater and dissolved substances such as metals are simultaneously coagulated,
As a purification treatment agent to be settled, montmorillonite, pyrophyllite, a natural mineral mainly composed of alumina and silicate such as kaolinite, calcium sulfate, an organic coagulant as a main component, and further, aluminum sulfate, aluminum chloride and A compound containing an alkali metal carbonate (Japanese Patent Application Laid-Open No. 10-165825) and the like have been proposed.
There is a point that it cannot be said that the floc is sufficiently satisfactory in any of the points such as the size of floc, the removal property of dissolved substances, and the coloring property of the treated water. It is the current situation.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to industrial wastewater,
It is an object of the present invention to provide a fine powdery purification agent capable of solving the above-mentioned problems in the treatment of polluted wastewater such as polluted wastewater or clean water, and a purification treatment method using the purification agent. It is. Specifically, polluted wastewater etc. can be separated into sludge and clean treated water in a very short time, and even if the wastewater is acidic or alkaline, it has a purification treatment capacity and can be separated. Since the treated water is almost neutral, there is no need to adjust the pH of the treated water when discharging, and fix and separate dissolved pollutants such as metals in polluted wastewater at the same time as coagulation and separation of polluted wastewater. Further, the separated sludge is stable and hardly soluble in water, so that a purification treatment agent capable of suppressing re-elution of pollutants, and a purification treatment method for clean water or wastewater using the purification treatment agent The purpose is to provide.

[0009]

As a result of various studies, the present inventor has used fly ash, which is conventionally considered to have no sufficient effect as a flocculant, as a flocculant main agent, and by using sodium ash in combination therewith. The above conventional problems can be solved all at once, in a very short time, the suspended solids can be coagulated as a large floc, the sludge separation and dewatering properties are good, and the wastewater is either acidic or alkaline. In this case, the treated water is almost neutral, so there is no need to adjust the pH of the treated water before discharging, and it also fixes and separates dissolved pollutants such as metals in the wastewater. The present invention has been accomplished by finding that a purification agent for solid fine powder can be obtained without re-elution of pollutants.

That is, the present invention comprises fly ash as a main coagulant and sodium carbonate, and further comprises other known inorganic and / or organic coagulants, as required, clinker ash, pH adjustment An object of the present invention is to provide a solid fine powder purification treatment agent containing an auxiliary agent such as an agent, activated silica, clay, a surfactant, and a redox agent. Further, the present invention uses fly ash as a coagulation main agent,
This is used in combination with sodium carbonate, and if necessary, other known inorganic and / or organic coagulants, and clinker ash, pH adjusters, activated silica, clay, surfactants, and redox agents The present invention provides a method for treating tap water or waste water using an auxiliary such as the above.

Hereinafter, the present invention will be described in more detail. In the present invention, fly ash is used as a main component of the flocculant. In the present invention, the aggregation main agent means that it plays at least a main role in aggregation, and is used as a purification treatment agent when used together with sodium carbonate. Therefore, the term "coagulant main agent" naturally includes the case where only fly ash is used as the coagulant. on the other hand,
Fly ash is fine porous ash powder mixed in flue gas discharged from a furnace when pulverized coal is burned in a thermal power plant, etc., and the flue gas is collected in a dry or wet dust collector. Was collected by applying Conventionally, fly ash has little utility value and is used only for landfills. Fly ash exhibits basicity when used as an aqueous solution (pH about 9 to 1).
1) The specific gravity is about 2.5 to 3.0. The chemical component ratio varies depending on the production area and combustion conditions of the coal, but generally contains mainly the following components.

( Component ) Content (%) Silicic acid (as SiO2) 34-60 Aluminum (as Al2 O3) 17-31 Iron (as Fe2 O3) 2-3 Magnesium (as MgO) 1-3 Calcium (CaO 0.5-10 Potassium 1-2 Carbon <10

As far as the powdery purification agent of the present invention uses fly ash as the main coagulant and uses sodium carbonate, other known inorganic or organic coagulants can be used as the coagulation aid. . Examples of such an inorganic coagulant to be used as an auxiliary include an aluminum salt such as a sulfuric acid band (aluminum sulfate), sodium aluminate, polyaluminum chloride (basic aluminum chloride), aluminum oxide, and aluminum hydroxide; Iron salts such as ferrous iron, ferric chloride and ferric sulfate; slaked lime; bentonite; and the like. Examples of the organic coagulant include sodium alginate, sodium carboxymethylcellulose (CMC), sodium polyacrylate, partially hydrolyzed salts of polyacrylamide, anionic (anionic) polymers such as maleic acid copolymer, and water-soluble. Aniline resin, polythiourea, polyethyleneimine, quaternary ammonium salt,
Cationic (cationic) polymers such as polyvinylpyridine, polyacrylamide, polyoxyethylene, gelatin, causticized starch, hydroxyethylcellulose,
Nonionic (nonionic) polymers such as water-soluble celluloses such as CMC and polysaccharides.

The powdery purification agent of the present invention may include clinker ash, if necessary, activated silica, clay, a pH adjuster, a redox agent, sodium dodecylbenzenesulfonate, which has been conventionally used as a coagulation aid. , Octadecylamine acetate, lauric acid and other surfactants are added,
It may be contained.

In the powdery purification agent of the present invention, the ratio of fly ash to the total amount of flocculant in the treatment agent, the ratio of fly ash to the total amount of treatment agent, and the preferred use ratio of fly ash to sodium carbonate are as follows: It depends on what kind of coal is used, that is, for example, what kind of coal is used as fuel, under what conditions combustion is performed, and the like. It also depends on what the treated water is. However, in general, the ratio of fly ash to the total amount of the fly ash and the conventionally known coagulant used supplementarily in the treatment agent is 100 to 50% by weight, and the fly ash relative to the total amount of the treatment agent Is preferably 95 to 10% by weight. The usage ratio of fly ash to sodium carbonate is 1 to 500 parts by weight of sodium carbonate with respect to 100 parts by weight of fly ash. Further, fly ash can be used as a mixture of two or more kinds, and a known coagulant used as an auxiliary may be used if necessary.
More than one species can be used in combination.

The powdery purification agent of the present invention is usually preferably in the form of a mixture in which all components are mixed, that is, in the form of a single agent. In other words, if the treatment agent is provided in a state where all components are mixed, in treating the water to be treated, the treatment agent is simply weighed, charged into the water to be treated, and agitated. It is not necessary to perform extra work such as measurement and mixing of the purifying agent components during the purifying process, and the purifying process is performed erroneously with the compounding amount, and as a result, the desired purifying is not performed. Is also released. However, each component as a separate agent may be added to the water to be treated at the same time or in an appropriate order, or the components of the purification treatment agent may be divided into several groups, and they may be mixed with each other. Of course, these may be simultaneously or sequentially charged into the water to be treated during treatment. Also, the amount of the purifying agent also varies depending on the type of the liquid to be treated, the solid concentration, the treatment conditions, etc., and cannot be determined unconditionally. However, it may be usually used at about several ppm to several 1,000 ppm, and particularly the solid concentration is high. In some cases, about 10% may be used.

The powdery purification agent of the present invention is mainly used for treatment of water and sewage, for example, polishing barrel wastewater, clutch manufacturer's etching wastewater, kraft pulp wastewater discharged in the papermaking industry, and pickling wastewater in the copper copper industry. It can be used for the treatment of various types of wastewater, such as the treatment of factory wastewater such as wastewater, the treatment of sludge from construction sites, the treatment of wastewater such as ready-mixed concrete, and the treatment of water in reservoirs, lakes, marshes and ponds. When the treatment of clean water or wastewater in the present invention includes any of these treatments, the wastewater containing Fe as dissolved metal such as a polishing barrel wastewater or an etching wastewater of a clutch maker using the purification treatment agent of the present invention is used. When processing,
Since the Fe in the wastewater can be almost completely removed from the treated water, the purification treatment agent of the present invention can be particularly preferably used for treating such industrial wastewater.

In the powdery purifying agent of the present invention, what kind of material is used as a known coagulant, clinker ash or coagulant, which is an optional component other than fly ash and sodium carbonate, which are essential components, and to what extent Whether it is used in an amount depends on what is the treated water to be treated, for example, whether it is sewage or what kind of industrial wastewater from what kind of factory, and how much the solid content of the treated water is. Since it is determined by various factors such as the presence of the substance and what kind of substance is dissolved in the wastewater, it is generally difficult to specify the additive material and the mixing ratio.
However, usually, by selecting and using an anionic synthetic polymer, a nonionic synthetic polymer, a sulfate band, activated silica, aluminum oxide, a flocculant such as aluminum hydroxide, a pH adjuster, clinker ash, montmorillonite and the like. Good results are often obtained.

When a polymer flocculant is used as a flocculant, a plurality of polymer flocculants such as a combination of two kinds of anionic polymers having different tendencies and one kind of nonionic polymer are used. When used simultaneously, good results are often obtained for various waters to be treated with the same composition. Usually, good results can be obtained by using these polymer flocculants in an amount of about 0.5 to 4% by weight based on the total amount of the purifying agent. In addition, when the water to be treated is alkaline wastewater, the addition of the sulfuric acid band often gives good results. When a sulfuric acid band is used, 3
It is usually used in an amount of about 40% by weight. Activated silica also has a high zeta potential and contributes to the aggregation of suspended particles. Activated silica is not necessarily used, but when used, it may be used in an amount of about 0.5 to 15% by weight based on the total amount of the purification agent.

Further, aluminum oxide is converted into ionized colloidal polycondensed aluminum hydroxide, which becomes an aluminum salt when dissolved in an acid, and becomes an aluminate when dissolved in an alkali, and has a ζ potential on the surface of the suspended particles. It will exert a lowering effect. Good results may be obtained when metal ions such as iron dissolved in the water to be treated are fixed and settled. When used, it is usually used in an amount of about 3 to 20% by weight based on the total amount of the purification treatment agent. Aluminum hydroxide has a pH value of the water to be treated.
Used when you want to adjust. This amount depends on the pH value of the water to be treated, but when used, it is used in an amount of 1 to 15% by weight, usually about 1 to 5% by weight, based on the total amount of the purifying agent.

Clinker ash is a porous material,
It is used not only for improving the dewatering characteristics of sludge but also for the purpose of the adsorbent. When emphasis is placed on dehydration or adsorption characteristics, the amount may be increased. When used, the amount is usually about 5 to 45% by weight based on the total amount of the purification agent,
For fly ash, for example, 10 to 50% by weight
Used in small quantities. In addition, if montmorillonite is used in an amount of 2 to 15% by weight based on the total amount of the purification agent, preferable results can be obtained. Preferred combinations of the purification treatment agent of the present invention and component ratios are shown below as examples.

Composition Example 1 is a preferred composition example emphasizing dehydration characteristics. Composition Example 2 is an example of a preferable composition that can correspond to various iron-containing treated waters having different pHs. Composition Example 1 (component) weight% fly ash 40-90 clinker ash 5-45 sodium carbonate (Na ₂ CO ₃ ) 3-10 montmorillonite 0-15 polymer flocculant 0-4 activated silica 0-15

Composition Example 2 (component) wt% fly ash 10-80 clinker ash 5-35 sodium carbonate 3-10 montmorillonite 2-20 aluminum oxide (Al ₂ O ₃ ) 3-20 aluminum hydroxide (Al (OH)) ₃ ) 0-5 Sulfate band (Al ₂ (SO ₄ ) ₃ ) 3-40 Polymer flocculant 0.5-4 Active silica 0-15

In the above-mentioned powdery purification treatment agent of the present invention, each component may be pulverized by a pulverizer such as a ball mill into fine powder and then mixed, or the components may be mixed in advance and then pulverized. The components may be placed in a grinder, or the components may be sequentially placed in a grinder to grind and mix. Further, these may be combined and pulverized and mixed. In the present invention, when the purification treatment agent is added to the water to be treated as one agent, each component in the treatment agent is easily dispersed and dissolved in the water to be treated, and the function of each component is possessed. It is necessary to carry out pulverization and mixing in such a state and particle size that they can be sufficiently exhibited.

The following effects can be obtained by treating tap water or waste water using the powdery purification agent of the present invention. a) One treatment agent can be used whether the pH of the water to be treated is acidic or alkaline. b) The formation speed of formed flocs is high. c) Large flocs are formed. d) Floc sedimentation speed is high. e) The volume of generated sludge is small. f) The sludge filtration rate is high, and the cake obtained has good releasability. g) Metals dissolved in the water to be treated can be almost completely removed. h) There is no re-elution of the removed metals into the treated water. i) The cake can generally be used for landfills and the like. j) The pH of the separated treated water is almost neutral, and there is no need to additionally provide a pH adjustment step before discharging.

When the powdery purification treatment agent of the present invention is used as one agent, the treatment agent may be directly added to the water to be treated, and it may be used for preparation of the treatment or dissolution of the treatment. No preparation work is required, and the charging step can be completed in a short time without any troublesome preparation work. In addition, the effects of the above-mentioned a) to j) can be similarly exerted by separately adding the components of the powdery purification treatment agent instead of using one component. As described above, due to the excellent properties of the purification treatment agent of the present invention, the thickener used for the purification treatment can be smaller than the conventional thickener, and the load of the sludge treatment step (for example, the filtration step) is reduced, and the thickness is reduced. Almost complete treatment of water and wastewater is possible in a short time.

[0027]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In the following example,
All percentages represent% by weight.

Example 1 The following components were pulverized into fine powders, and then mixed to produce a purification agent. ( Component ) % fly ash 70 Clinker ash 8 Sodium carbonate (Na ₂ CO ₃ ) 6 Polymer flocculant (Ebagrose A120) 1 Polyzoa 15

This cleaning agent was added to the following polishing barrel wastewater (raw water) in No. 1 of Table 1. A sedimentation test was performed by adding the amounts described in 1-4 and stirring. The size of the formed floc, the reaction time, the turbidity after standing for 10 minutes, the pH of the supernatant, and the iron ion content were measured. Table 1 shows the results. (Raw water) pH: 2.5 / 21 ° C., Fe ²⁺ content: 80 mg /
L

[0030]

[Table 1]

Note that "L" in the flock size column indicates that the flock size was large. The reaction time was determined by visually observing the time at which floc generation started after the addition of the purifying agent. Further, the turbidity was measured by a colorimetric turbidity meter. No. Filtration of each of the sludges 1 to 4 was easy and the water content of the sludge was low. Also, the peelability of the cake was good.

Comparative Example 1 A purification agent was prepared in the same manner as in Example 1 except that sodium carbonate was not used. 4-8
And the same sedimentation test as in Example 1 was performed. Table 2 shows the results.

[0033]

[Table 2]

Example 2 The following components were pulverized into fine powders, and then mixed to produce a purification agent. ( Component ) % fly ash 32 Clinker ash 14 Sodium carbonate (Na ₂ CO ₃ ) 6 Polymer flocculant (Sanpoly-A511) 1 Polyzoa 15 Sulfate band 32

This purifying agent was added to the following red muddy water, as shown in Table 1.
No. A sedimentation test was performed by charging and stirring the amount described in 9 to 12. Size of formed floc, reaction time, turbidity after standing for 10 minutes, p of supernatant
The contents of H and iron ions were measured as in Example 1. Table 3 shows the results. (Red muddy water) Added red mud amount: 40,000 ppm, pH: 7.2 / 21
° C

[0036]

[Table 3]

[0037]

As described above, according to the present invention,
It is now possible to effectively use fly ash, which was previously only used as landfill for landfills, etc., and by using the purifying agent of the present invention or by adopting the purifying method, floc formation, sedimentation speed Good results can be obtained in any of filterability, water content of filter cake, treatment time, removal of dissolved metal, pH value of treated water, and the price of purification agent is lower than conventional ones Therefore, it is possible to obtain an excellent effect that it can be manufactured easily, does not require much processing, and can contribute to downsizing of facilities.

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Claims (6)

[Claims] 1. A powdery purifying agent comprising fly ash as a main coagulant and sodium carbonate. 2. The powdery purifying agent further comprises at least one of a coagulant other than fly ash, clinker ash, activated silica, clay, a pH adjuster, a redox agent and a surfactant. The powdery purification treatment agent according to claim 1, wherein 3. The powdery purifying agent contains at least one selected from the group consisting of fly ash, sodium carbonate and clinker ash, montmorillonite, aluminum oxide, aluminum hydroxide, a sulfate band, a polymer flocculant and activated silica. The powdery purification treatment agent according to claim 1, wherein 4. The powdery purifying agent is a fly ash 10
~ 90% by weight, clinker ash 5 ~ 45% by weight, sodium carbonate 3 ~ 10% by weight, montmorillonite 2 ~ 15
% By weight, 0 to 20% by weight of aluminum oxide, 0 to 5% by weight of aluminum hydroxide, 0 to 40% by weight of sulfuric acid band, 0 to 4% by weight of polymer flocculant, and 0 to 15% by weight of activated silica. The powdery purification agent according to claim 3, wherein 5. A method for purifying tap water or waste water, wherein fly ash is used as a coagulant main agent, and a purifying treatment of tap water or waste water is carried out by using this in combination with sodium carbonate. 6. The method for treating tap water or waste water according to claim 5, further comprising clinker ash, montmorillonite, aluminum hydroxide, aluminum oxide, a sulfate band, a polymer flocculant and active silica together with fly ash and sodium carbonate. At least one selected from
A method for treating tap water or waste water, wherein seeds are used in combination.