Flocculating agent

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention is a coagulant used for treating suspended solids such as sludge, sludge, sludge, etc. floating in rivers, reservoirs, golf course ponds, general factory wastewater, etc., and hydrophilic mud-like substances associated with the lifting of accumulated sludge. In particular, the present invention relates to a flocculant from which purified water can be obtained by coagulating and precipitating colloidal substances and suspended solids contained in a hydrophilic sludge.

【0002】

[Conventional technology]

Hydrophilic mud such as sludge and suspended solids of ultrafine particles that accumulate and float in rivers and the like not only give off an offensive odor and cause environmental pollution, but also cause water pollution. For this purpose, a flocculant is added to factory wastewater containing suspended solids and each water area, and a colloid is added when the sludge accumulated in each water area is lifted to remove colloidal substances and suspended solids. By coagulating and sedimenting, pollutants and clear and clean water are separated. As such a flocculant, usually, one kind of inorganic metal salt such as silicic acid and calcium sulfate, or a combination of such one kind of inorganic metal salt and an organic compound is first coated with the inorganic metal salt. After adding to the treated water to form primary flocs, a polymer organic compound is added to the water to be treated to coagulate and settle colloidal substances and suspended substances.

【0003】

[Problems to be Solved by the Invention]

When one kind of inorganic metal salt such as silicic acid is used, since the inorganic metal salt is almost neutral, the treated water is also in the neutral region, and there is an advantage that it does not adversely affect the environment or the like. There is. However, since the primary flocs formed by the addition of the inorganic metal salt are as small as about 0.3 mm to 0.5 mm, the aggregation ability is small. As a result, the sedimentation rate is slow, the treatment time is long, and the suspended substance or the like cannot be completely separated from water. Furthermore, as the concentration of suspended water increases, the coagulation ability effect is hardly observed. Therefore, there is a problem that the treated water cannot be completely made transparent, and there is a problem that the treatment time becomes too long, so that the peripheral equipment loss is large and the running cost becomes very high.

【0004】

On the other hand, in the flocculant in which the polymer organic compound is added to one kind of inorganic metal salt, the primary flocs formed by the inorganic metal salt adsorb colloidal particles by the cross-linking action of the added polymer organic compound. Therefore, the flock gradually increases. Therefore, the sedimentation speed is high and the aggregation effect is excellent.

【0005】

However, high molecular weight organic compounds may have an adverse effect on the environment due to secondary contamination, putrefaction of flocculants, etc., and it is preferable to refrain from using them as much as possible. Further, when a polymer organic compound is used, the flocs increase due to the cross-linking reaction. Therefore, the size of the flocs is proportional to the amount of the polymer organic compound added within the range in which the cross-linking reaction is carried out, but the cross-linking occurs. When the reaction is completed, the surface of the flock is covered with the polymer organic compound, and the flock does not increase further and the aggregating action is stopped. Therefore, when the amount of the polymer organic compound is small with respect to the water to be treated, the agglutination reaction is completed in a state where the flocs do not become completely large, and the treated water is not completely transparent and is in a suspended state. Become. On the contrary, if the amount of the high molecular weight organic compound is large, when the agglutination reaction is completed, many agglutinants are wasted without exerting the agglutination action, which adversely affects the environment and increases the running cost. It will be expensive and the long-term economic efficiency will be impaired.

【0006】

In addition, some high molecular weight organic compounds do not effectively agglomerate depending on the proportion of clay components in the water to be treated. Therefore, it is necessary to analyze the water to be treated and select a high molecular weight organic compound that effectively exerts an agglutinating action.

【0007】

The present invention solves such a problem, and an object of the present invention is to provide a coagulant which has no risk of adversely affecting the environment such as secondary pollution and putrefaction of additives and has excellent coagulation performance. To do.

【0008】

[Means for solving problems]

The flocculant of the present invention is characterized in that it is composed of a plurality of inorganic compounds with calcium oxide as a main component, thereby achieving the above object.

【0009】

[Action]

Since the flocculant of the present invention is composed of a plurality of inorganic compounds containing calcium oxide as a main component, a flocculation effect proportional to the amount added can be obtained, and even if it is used in a large amount, it adversely affects the environment. There is no fear.

【0010】

[Example]

Hereinafter, examples of the present invention will be described.

【0011】

The flocculant of the present invention is composed of a plurality of inorganic compounds containing calcium oxide as a main component. An example is shown in Table 1.

【0012】

[table 1]

<img file="JPH06339602A_D0001.tif" />【0013】

As described above, the flocculant of the present invention does not contain a high molecular weight organic compound and contains only a plurality of inorganic metal salts, in particular, about 1/3 (% by weight) is calcium oxide (CaO) and about 1/5 (% by weight). The silicic acid (SiO)₂), It does not adversely affect the environment and has a pH of 7 to 8, which is almost neutral and weakly alkaline. This flocculant is a gray powder having a specific gravity of 2.30.

【0014】

Such flocculants are usually aluminum oxide (Al).₂O₃) Solution and iron chloride (FeCl)₃) The solution can be used as an adjunct to completely neutralize the treated water. The concentration of the aluminum oxide solution is preferably about 10.0 to 11.0%, and the concentration of the iron chloride solution is preferably about 37.0 to 39.0%.

【0015】

The amount of the coagulant of the present invention added varies depending on the properties of the water to be treated such as muddy water to be coagulated, but usually 200 g / m.³~ 700g / m³It is added to the water to be treated at a rate of about. Auxiliary agent is usually 100cc / m³~ 350cc / m³It is added to the water to be treated at a rate of about. Moreover, even if a large amount of the main agent and the auxiliary agent are added to the water to be treated, the environment is not adversely affected.

【0016】

The agglutinating performance of such a coagulant was tested. 250 mg of the flocculant of the component shown in Table 1 was added to 500 cc of mud water having a mud content of 10% as the water to be treated, and the mixture was stirred. Subsequently, aluminum oxide (Al) was used as an auxiliary agent to neutralize the treated water.₂O₃) Solution 1cc and iron chloride (FeCl)₃) Solution 0.5cc was added and stirred. The results shown in Table 2 were obtained when the amount (depth) of aggregates deposited after 2 minutes, 5 minutes, and 10 minutes was measured and the particle size of flocs was examined. The treated water was transparent.

【0017】

[Table 2]

<img file="JPH06339602A_D0002.tif" />【0018】

For comparison, 250 mg of a coagulant using aluminum sulfate (powder), which is one kind of inorganic metal salt, was put into 500 cc of the same muddy water as the water to be treated, and the coagulation performance was tested. The results are shown in Table 3.

【0019】

[Table 3]

<img file="JPH06339602A_D0003.tif" />【0020】

As described above, in the flocculant composed of one kind of inorganic metal salt, the flocs formed were small, and the fast sedimentation rate as in the flocculant of the present invention could not be obtained. The treated water was also slightly turbid, and the transparency as in the present invention could not be obtained.

【0021】

Furthermore, for comparison, a similar experiment was conducted using an anionic polymer flocculant as the organic flocculant. In this case, 1 cc of polyaluminum chloride was added to 500 cc of muddy water to be treated in advance and stirred to form a primary floc, and then 25 cc of a 0.1% solution of an anionic polymer flocculant was added and stirred. .. The results are shown in Table 4.

【0022】

[Table 4]

<img file="JPH06339602A_D0004.tif" />【0023】

As described above, when an organic coagulant is used, a slightly superior coagulation effect can be obtained as compared with the coagulant of the present invention, but it is composed of a plurality of inorganic metal salts in consideration of adverse effects on the environment. The coagulant of the present invention is not inferior to the coagulation effect of an organic coagulant, and exhibits a far superior coagulation effect as compared with the case of using a single inorganic salt.

【0024】

[Effect of the invention]

Since the flocculant of the present invention is composed of a plurality of inorganic compounds containing calcium oxide as a main component, there is no risk of adversely affecting the environment even if it is used in a large amount, and it is excellent in flocculation. It works. The result is clear, neutral treated water. Furthermore, the aggregation ability does not change depending on the ratio of the clay component or the like in the water to be treated, and therefore it is not necessary to analyze the components of the water to be treated.