KR960014034B1 - Method for production of alginate having coagulation assistant function - Google Patents

Abstract

The alginate coagulation aid is prepared for eliminating the remained aluminum and heavy metallic ion, etc. in waterworks source water and running water. The method for removing them is composed of treating the waterworks source water by charging 30 mg/l aluminum sulfate for water purification and charging 1.0-6.0 mg/l alginate of natural polymeric material into the purified water for removing the remained aluminum.

Description

Process for preparing alginate coagulant aid for treating raw water

1 is a device used in an embodiment of the present invention.

2 to 9 are diagrams tested in the embodiment of the present invention.

The present invention is a polymer coagulant, the main component of the cell membrane of brown algae (류, seaweed, kelp, seaweed, etc.) and chemically belonging to carbohydrates, unlike starch, fibrin, etc. The present invention relates to a method for producing flocculation aids capable of simultaneously treating aluminum, turbidity, and heavy metals present in constant raw water and tap water.

BACKGROUND ART Conventionally, a large amount of aluminum sulfate or polyaluminum chloride is used as a flocculant having a cohesive effect in flocculation of suspended solids present in drinking water in a conventional drinking water.

Thus, when agglomeration of constant raw water with only aluminum sulfate or polyaluminum chloride, it has been taken for granted that a large amount of aluminum ions are contained in the constant raw water.

Meanwhile, according to a recent newspaper report, the water quality of tap water and raw water in 14 cities including Busan, Ulsan, and Seoul was analyzed. The average concentration of aluminum in raw water was 0.167 mg / l, 0.171 mg / l in Incheon, Gayang and Paldang Dam, and 0.104 mg / l in Hoesa Dam, Ulsan.

In tap water, 0.196 mg / l in Busan, 0.197 mg / l in cod, and 0.169 mg / l in Ulsan were detected relatively high, which was about twice as high as 0.096 mg / l in Chuncheon.

In Busan, in particular, Hwamyeong Reservoir Water Purification Water and 10 tap water supplies from the reservoir were investigated twice, which exceeded the 0.2mg / l standard set by the World Health District. As many as 50% were located in Cheongju, 45% in Gwangju, 42% in Gwangju, and 26.3% in Ulsan, the concentration of residual aluminum is high in most tap water in Korea. (報道) has been.

Miller [Miller. R. G. et al, The occutrence of aluminum in drinking water J: Amer. water works assoc. 76 (1), pp. 84-91 (1984)] reported that the concentration of aluminum in drinking water increased by about 40-50% by using aluminum sulfate as agglomerate in the coagulation treatment of constant water.

Increasing aluminum concentration in tap water is known to increase turbidity, reduce disinfection effect, and cause aluminum to adhere to water pipes, thereby reducing water transport capacity. Human health effects include neuropathologic disorders, Alzheimer's diseases (neurological diseases), presenile dementia and convulsions. If it is contained in tap water can cause a lot of problems.

Currently, the water purification method used in Korea goes through 10 processes such as water intake, water purification plant, water imperfection, mixed land, and water purification plant.

In this process, a mixture of aluminum sulfate as the main agglomerate, polyaluminum salt as the coagulant, slaked lime, activated carbon, and liquid chlorine Due to the addition, the residual aluminum concentration is inevitably detected in the tap water higher than the constant raw water.

Therefore, if you do not use aluminum sulfate alone in the water purification process, and if you combine it with natural foods that can be eaten, you will have a very good coagulation effect (凝集 效果). Development of a flocculant capable of simultaneously removing aluminum, turbidity, and heavy metal ions present in constant raw water and tap water. I) tried.

When explaining the embodiment according to the manufacturing method of the present invention through the experiment.

As a chemical gaiters used in the experiment of the present invention, Jar tester (Jar tester) as shown in Figure 1 was used.

Example 1

The sample to be used in this experiment is a constant raw water taken from the S intake, and is currently being evaluated as a constant water quality second grade, the analysis of the characteristics of the beverage is shown in the following table.

As shown in the above table, the sample water represents the water quality suitable as a water source in Korea's water quality standards. However, this sample contains trace amounts of various anionic substances and harmful heavy metals due to the inflow of industrial facilities, livestock facilities, agricultural activities and household sewage adjacent to the water supply.

NASF-500 (A) NSA-500 (M) and NASF, which are aluminum sulfate and alginate, for a certain sample amount using a device in FIG. 1 of Example 1 -500 (M) was added to determine the optimal dose of flocculant. In addition, the temperature of the sample water was kept constant at 19.8 ℃ and the operation of the chemical stirring device was carried out in the following procedure.

First, each sample is filled into six 1 liter beakers in a fixed amount, and then, without adding pH-controlling chemicals to the drinking water, aluminum sulfate and aluminum sulfate + alginate are added, followed by rapid stirring at 200 rpm for 5 minutes, and then 5 minutes at 40 rpm. Slow stirring was performed.

Then, it was allowed to settle for about 30 minutes, and the supernatant was collected for quantitative analysis.

At the present water treatment plant, the concentration of aluminum sulfate and polyaluminum chloride is approximately 30-50 mg / l, depending on the inflow of raw water. Is controlled by. Therefore, in this experiment, aluminum sulfate was added in the range of 10 mg / L-60 mg / L under the same conditions as the water purification plant, and the quality of the treated water was measured. The amount of change in residual turbidity and residual aluminum according to the aluminum dose was shown in FIG. 2.

(Drawing 2)

Considering this figure, the concentration of the optimum aluminum dosage of 7.32 mg / l at the dosage of aluminum sulfate of 30 mg / l or more is rapidly increasing at higher doses. The phenomenon is showing. This phenomenon may occur between a turbidity-inducing substance in water and aluminum ions, but the presence of a relatively large amount of aluminum will naturally increase the aluminum ion concentration. However, when 30 mg / l of aluminum sulfate was administered, the residual aluminum concentration in water was about 7.0 mg / l, which is about 1800 compared to the 0.004 mg / l of aluminum ion contained in constant water. It becomes a fold increase.

In addition, Drescoll et al. Found that the concentration of aluminum in constant raw water was 0.01 mg / l, and the coagulated and filtered tap water was 0.048 mg / l, which is about five times the amount of aluminum in constant raw water. I have reported it. Foreign drinking water quality standards for residual aluminum are 2 mg / l in Japan, 0.2 mg / l in Germany and 0.2 mg / l in WHO.

Comparing these standards with the reality of Korea shows that there are enormous differences.

Example 2

Alginate salts such as NASF-500 (A), NSA-500 (M), NSAF-500 (M), etc. in a sample administered with 300 mg / l of aluminum sulfate. Was administered to 1.0 mg / l-6.0 mg / l, and then the dose change, the residual turbidity, and the aluminum concentration change were related to each other.

(Fig. 3)

Referring to FIG. 3, when the concentration of alginate was 2.0 mg / l, the residual turbidity was 0.2 NTU. When 2.0 mg / l or more was added, the residual turbidity component increased. This phenomenon is presumed to be due to the excessive addition of alginate, which does not act as a coagulant but rather exists in water as a turbidity component.

On the other hand, the concentration of residual aluminum produced in turbidity removal with aluminum sulfate decreased gradually as the amount of alginate NSAF-500 (A) was added to the water, which was about 7.0 mg / l, and the residual aluminum when 2.0 mg / l was added. The concentration of was about 2.0 mg / l.

It can be seen that about 71.4% of aluminum ions remaining in water were removed by alginate.

These results are similar in alginates such as NASF-500 (A) and NSAF-500 (M).

From this diagram, the proper dosage of aluminum sulfate and alginate can be found.

Example 3

For reference, the relationship between residual turbidity and aluminum concentration according to the amount of alginate added, such as NSA-500 (A) and NSAF-500 (M), is shown in Tables 4 and 5, respectively.

(Fig. 4)

(Fig. 5)

This phenomenon of decrease in addition to the residual aluminum alginate is probably due to the action of COOH functional groups in the molecules constituting the alginate. It can be assumed that this is because the aluminum ions present in the water are adsorbed.

Example 4

The coagulant dosage of the raw water was 30 mg / L according to the above experimental results, but the concentration of aluminum sulfate was investigated to examine the relationship between the aluminum sulfate dosage and the heavy metal removal in water. The results of experiments varying up to 10 mg / l-60 mg / l are shown in FIG. 6.

(Fig. 6)

In this figure, the concentrations of zinc copper and iron ions decreased below 1.0 mg / l.

This is probably considered to be an aggregation effect by aluminum sulfate.

This chart shows the heavy metal removal efficiency.

Example 5

On the other hand, alginate salts such as NASF-500 (A), NSA-500 (M), NSAF-500 (M), etc. were prepared in a sample in which 30 mg / L aluminum sulfate was administered. When the dose was changed from 1.0 mg / L to 6.0 mg / L, the change in the residual heavy metal concentration was measured and shown in FIG. 7, FIG. 8, and FIG. 9.

(Fig. 7)

(Fig. 8)

(Fig. 9)

Observing these figures, the concentrations of zinc, copper and iron ions were about 1.0 mg / l regardless of the various alginate doses.

As described above, in the present invention, when the raw water is agglomerated with only aluminum sulfate or polyaluminum chloride, aluminum ions are contained in the constant raw water and the concentrations of zinc, iron, and copper are increased as the injection concentration of aluminum sulfate is increased. The addition of alginate decreased to about 1.0 mg / l or less, and the addition of aluminum sulfate increased the sulfate ion to about 40 mg / l, but the effect of a slight decrease when adding alginate was constant. As a raw water flocculant, Alginate, a natural polymer that is edible without using aluminum sulfate alone in water purification process, is used. At the same time, there is an effect that can be removed.

Claims (1)

30mg / l of aluminum sulfate was administered as in the above example to treat the purified water, and then the alginate was administered at 1.0mg / l-6.0mg / l in order to remove the remaining aluminum. A method of producing alginate coagulant for constant water treatment, which can simultaneously process residual aluminum, turbidity, and heavy metals.