JPS59186695A - Treatment of waste water containing organic reducing material - Google Patents

Abstract

PURPOSE:To accelerate a reduction in COD and the speed for removing org. materials by adding the metallic ion that forms an org. metallic complex by the org. reducing materials into waste water, irradiating light thereto and performing an ozone treatment. CONSTITUTION:A prescribed amt.of metallic ion such as iron ion which forms an org. metallic complex is added to waste water contg. org. reducing materials. The ion iron is added at 0.5-2.0 molar ratio of the org. reducing materials. The waste water is then subjected to an ozone treatment under irradiation of UV- visible light and further the similar treatment is applied thereto by maintaining <=5pH. The decrease in COD and the removal of the org. materials are thus accelerated and the ozone reactor is made compact; moreover, the amt. of the ozone to be consumed in decreasing the COD and removing the org. materials is decreased and the treatment of the waste water with high overall efficiency and practicability is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides COD (COD) based on organic reducing substances in wastewater.
Chemical Oxj, gen Demancl
: method of reducing chemical oxygen demand) and 7 dimensions or T
OC (Total Ovganic Carbon:
The present invention relates to a method for removing total organic carbon (total organic carbon).

Organic reducing substances in wastewater not only cause coloration and odor, but also increase COD and TOC.

In recent years, regulations on COD a content have been implemented.9. In particular, an efficient and economical removal method has become desirable.

As a conventional method for removing organic reducing substances, #: Precipitation and continuous biological treatment are considered to be economical, but there are problems in removing soluble WL organic substances and reducing COD. This is a well-known path. For wastewater to which these treatment methods cannot be applied, incineration is used in some cases, but this method is generally not acceptable due to secondary pollution and economic considerations.

The ozone treatment method utilizes the oxidizing power of ozone to oxidize and decompose organic substances, and is effective for decolorizing and deodorizing. In other words, although it is possible to reduce COD, the amount of ozone consumed was excessive, and due to the limit of ozone's oxidizing power, C
In some cases, it was not possible to achieve a high degree of reduction in OD. The latter CO
Regarding D reduction, acceleration of the ozone reaction by combined use of light irradiation has been obtained as a prior art, but there is still room for improvement, and there has been no noticeable improvement in the ozone consumption of the former. Not served.

This invention was made with the aim of overcoming the drawbacks of the ozone treatment method, such as the excessive consumption of ozone and the limitations of COD reduction and TOC removal. Metal ions are added and ozone treatment is performed under light irradiation.

The present invention will be described in detail below. Figure 1 shows a general outline of the experimental apparatus. (1) is an ozone generator, (2
) is an ozone reactor, (3) is an ozone-containing gas diffuser plate, (
4) is a lamp storage jacket, (51 & j lamp).

(6) Niosin isthometer, and (7) Ha exhaust ozone decomposer.

The experiment was carried out at a concentration of 1 TO, C including 220 ppm citric acid.
1.81 of the water to be treated containing 50 ppm of reducing organic matter was charged into the reactor (2), and the lamp (5) was turned on or off with or without the addition of all iron ions as shown in Table 1 below. A method was adopted in which the lights were turned off and oxygen containing 20 m9/11 of ozone was continuously supplied to the reactor (2) at a flow rate of 11/min for a certain period of time. After carrying out the above reaction for a certain period of time, a portion of the treated water was removed and subjected to analysis.

FIG. 2 shows the results of an experiment showing the effects of the present invention.

CO depending on reaction time under treated water and conditions shown in Table 1
This is a comparison of D decrease. Note that the numbers for the water to be treated in Table 1 correspond to the numbers in FIG.

Table 1 Comparing the COD reduction curve (4) by conventional ozone treatment and the curve +1 by the method of the present invention, the difference is remarkable, and the rate of decrease in COD is remarkable due to light irradiation with the addition of iron ions. It turns out that it can be promoted. Curve (3) obtained by combining light irradiation and ozone treatment by combining Figure 2 with 19.
, and the curve (2) obtained by iron ion addition ozone treatment are also shown, which shows that the combined use of iron ion addition and light irradiation produces an even more remarkable effect.

FIG. 3 shows the relationship between COD reduction and consumed ozone amount in the same experiment as FIG. 2. Again, the numbers correspond to those in Table 1. It is clear from the figure that the method according to the invention allows a high reduction in COD with the lowest ozone consumption.

The above example uses a low-pressure mercury lamp (irradiation wavelength 185 nm).
Although this is an example of irradiation with VC (253.7 nm), the same effect can be obtained using a high pressure mercury lamp (irradiation wavelength 250 to 600 nm) with metal.

Figures 4 and 5 show the same treated water VC as in Figures 2 and 3.
On the other hand, ysoppm of iron ions were added.

This figure shows the reduction in COD by ozone treatment with and without light irradiation with a 100 W high-pressure mercury lamp. If the method according to the invention has a COC reduction rate, then
It is clear that there is a significant improvement in reducing the amount of ozone required for OD reduction.

In the examples of the present invention, the amount of iron added greatly affects the treatment effect.

Figure 6 shows water control (T) containing citric acid (220 ppm).

C=150ppm, of which TOC due to citric acid=4
0.0 molar ratio to citric acid for 1ppnl)
．． 5゜High-pressure mercury lamp (100W) with different amounts of iron ions added such as 1.0, 1.5, and 2.0
This figure shows the results of a test in which ozone treatment was performed while irradiating COD, and shows the time required to remove 95% of COD and the treatment efficiency during that time. If the amount of iron ions added is less than 1.0 in molar ratio to citric acid, the smaller the amount of iron ions added, the more the amount of ozone and reaction time required to reduce the unit COD will increase.

When the molar ratio is 10 or more, even if an excess of iron ions is added, there is no significant change in the amount of ozone required and the reaction time required for treatment. Zunawachi.

In order to increase the efficiency of ozone treatment (reduce the amount of ozone required), it can be said that it is necessary to add citric acid and iron ions in the order of mol. Of course, addition of iron ions 1if
Even if the amount is less than equimolar, it can be expected that iron ions will improve the removal efficiency of organic matter to some extent.

Therefore, the molar ratio of iron ions to citric acid [F2VC] is 05 to 20. Preferably, it is desirable to set it as 08-15.

It should be noted that no significant difference in treatment effect is observed whether the iron ions added are in the form of ferrous or ferric ions.

From the above results, the effect of adding iron ions.

It can be assumed that the complex formation of citric acid and iron ions makes it more reactive with radicals such as ozone or OH radicals generated by the action of light and ozone than with free citric acid. . That is, it is presumed that the coordination of iron ions to citric acid increases the atomic density of citric acid molecules and improves the reactivity with ozone and OR radicals, which have high electrophilic reactivity. Therefore, the invention can be widely applied not only to citric acid but also to organic reducing substances that completely form metal complexes, such as ethylenediaminetetraacetate M. Furthermore, the metal ions added are not limited to iron ions, and form organometallic complexes. Mn.

A similar effect can be expected with co, etc.

Next, regarding the influence of the pH of the wastewater to be treated.

Figures 7 to 10 show Ze1 water (citric [= 220 ppm, TOC = 150
ppm + iron ion addition: 75 ppm) while irradiating with a crystallizing mercury lamp (100 W). The amount of ozone required for this process is large and unconscionable.At a pH of 50 or less, especially at a pH of 3, organic matter can be treated efficiently, even down to low concentrations.

From this, when carrying out the present invention, the total pH is 5 or less,
It is necessary to adjust the desired size to about 1 to (, i'l,, 3).

Broadly speaking, one of the effects of the present invention can be pointed out to be an increase in the ozone absorption rate in the ozone reactor due to acceleration of the ozone reaction rate. What is the ozone absorption rate?

(Ozone in the supplied ozone-containing gas - degree - ozone in the exhaust gas (mfBl) / (ozone concentration in the supplied ozone-containing gas) It can be used for U, and the cost required for the combined ozone component 'M can be reduced.

As described above, according to the present invention, in order to reduce the COD of wastewater and remove organic matter, it is possible to reduce the COD of wastewater and remove organic matter by adding metal ions that form organometallic minerals such as iron ions to the wastewater, and By performing ozone treatment while fully irradiating with light, or by performing the same treatment while keeping K PH at 5 or less.

COD reduction and organic matter (TOC) removal rates are accelerated, while the ozone reactor becomes more compact.

The amount of ozone required for C9D reduction and TOC removal is reduced, and we hope to find an overall efficient and practical method for treating pipe wastewater.

[Brief explanation of the drawing]

Figure 1 is used to confirm the effects of the present invention.
t&'j ozone generation <=, (2) TS ozone reactor, (3) ozone-containing gas diffuser, (ABS lamp storage jacket), +5) lamp, (6) ozone concentration meter, (knife) is an exhaust ozone decomposer. Agent Masuo Oiwa Figure 1 Figure 2 Reaction time ffJ> Figure 3 Wei Huang Ont (PPm) 0.5Q
120 reaction time Il! l (min) Fig. 5 3 Ozone amount (ppm) Fig. 6 Iron ion≧/citric acid (mole ratio) 2-2-3 Marunouchi, Chiyoda-ku, Tokyo

Claims (1)

[Claims] (1) In the treatment of wastewater containing organic reducing substances. A metal ion that forms an organometallic complex with the organic reducing substance is added to the wastewater, and in the presence of the metal ion, light is irradiated and ozone treatment is performed using ozone. A method for treating wastewater containing organic reducing substances. (2) In the treatment of wastewater containing organic reducing substances. The pH of the wastewater is maintained at 5 or less, metal ions that form an organic metal complex with the organic reducing substance are added to the wastewater, and light is irradiated in the presence of the metal ions. A method for treating wastewater containing organic and bulk substances, which is characterized by performing ozone treatment using ozone. (3) In the treatment method according to any one of claims 1m and 2, the metal ion is. A method for treating wastewater containing organic reducing substances, characterized by using any one of Fe, Isoin, and CO. +4) Range of Permissible Percentage Required In any one of the treatment methods in Items 1 and 2, the amount of the metal ion added is set at a molar ratio of 0.5 to the organic reducing substance forming the metal complex. A method for treating wastewater containing organic reducing substances, characterized in that the concentration is 2.0 to 2.0. (5) A method for treating wastewater containing organic reducing substances, characterized in that the amount of the ions added is, in particular, 0.8 to 1.5 in the method of claim 4. (6) A method for treating wastewater containing organic mono-reducing substances, characterized in that the pH of the wastewater is set to 3 in the method of claim 2. (1zo lower whitening 2