JPS59139991A - Colored water disposal - Google Patents

Abstract

PURPOSE:To remove chromaticity, etc. in water, while inhibiting the formation of trihalomethane, by adding coagulating treatment and treatment using a catalyst to a method for treating colored water having chromaticity derived from putrid substance such as humic acid with O3. CONSTITUTION:Colored water inside a raw water tank 1 is introduced into an O3 reaction column 3 by a pump 2, catalytically reacted with O3 from a generator 6, introduced into a filtering column 4 packed with Mn sand and filtered therein with a filtering bed 4a having the coating film of an activated MnO2 catalyst. By this filtration, the decomposition of residual O3 in the water is concurrently performed, while suppressing the total amount of trihalomethane. Treated water is obtained in a tank 5. Hereon, the mixing of aluminum sulfate from a tank 7 and coagulation are performed in the bed 4a to remove chromaticity and dissolved Mn and iron from the water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to colored water treatment, and in particular, colored water is subjected to a contact reaction treatment with ozone and then filtered through a contact filtration layer that undergoes coagulation treatment and a manganese dioxide catalyst coating. By doing so, the production of trihalomethanes is suppressed while the chromaticity of small and medium particles is removed.

As the penetration rate of water supply increases, there has been a demand for improved water quality, but in addition to this, the depletion of raw water sources and deterioration of water quality are causing problems in advanced treatment methods for drinking water, etc.

Especially in recent years, carcinogens associated with chlorination of tap water.
・For lomethane production, the conventional water quality standard item is the concentration regulation value in ppm units, f; Correspondingly, water from open-cut and deep wells has a large amount of colored water due to humic substances such as humic acid and fluorocarbons, and furthermore, these humic substances have not only chromaticity but also Turin water. Since it is a precursor for lomethane production, there is a need to review the treatment process.

In general, colored groundwater has high alkalinity and high pH value, and contains dissolved manganese, iron, and ammonia nitrogen, so currently, it is treated with high-concentration pre-chlorination, coagulation-sedimentation treatment using sulfuric acid, etc. In addition, catalytic oxidation treatment using manganese sand is also used, but the optimum pi for aggregation of chromaticity components
-1 value is low at 5 to 6, and in addition to the high alkalinity, if flocculation treatment is performed without pH control with acid, not only will a large amount of sulfuric acid be used, but there will be almost no turbidity component. For this reason, the flocs produced are brittle and have extremely poor settling properties, making treatment extremely difficult.

Therefore, in order to solve these problems, the present invention has first demonstrated that ozone treatment is extremely effective for decolorizing colored water caused by humic acid, and that ozone and hydrogen peroxide were used in experiments on artificial humic acid colored water. It was proposed that the treated water treated in combination would be chemically stable against chlorine treatment and the production of chloroform would be significantly reduced, but it was also proposed that coagulation treatment and treatment with a contact catalyst would be added to this, resulting in an integrated process. This is intended to treat colored water.

Next, the present invention will be explained in detail based on examples.

The raw water A, B, and 0 from three water purification plants whose water source was a deep well and whose chromaticity was caused by humic substances were used in the experiment, and the water quality was as shown in Table 1.

Table 1: NF-1 unfiltered sample 1・゛...045 μm filtered water Ammonia is also present and the water has a high chlorine demand.

In carrying out the method of the present invention, as a preliminary test, in order to see the independent effects of the treatment method, we first examined how much chlorine was produced in Torino-Rome tankers when chlorine was added to the three types of raw water mentioned above. Drawings plotting the progress (Figures 2 to 12)
The symbol inside is Qma total trihalomethane amount TTI-IM
, the produced torinomethane, chloroform to TOM
, Fromozik mouth methane BDOM, dibromochloromethane DOBM.

Bromoform is called TBM.

300 m7 of raw water from the three types mentioned above! Figures 2 to 4 show the changes in water value when the samples were taken and sodium hypochlorite was added to each sample, and the samples were allowed to stand for 24 hours in a constant temperature bath at 20°C. According to this, as the amount of chlorine added increases, the amount of TTIIM rapidly increases due to the appearance of free chlorine, and after that it becomes stable against the increase in free chlorine. The presence of free chlorine also causes TTH
It can be seen that M is reliably generated.

Next, regarding ozone treatment, three types of raw water are treated at ozone injection rate s.
The results of decolorization treatment at rq/t and contact time of 10 minutes are shown in FIG. In addition, even after ozonation treatment, tap water must still contain residual chlorine, so chlorine must be added, and in order to see the results, hypochlorous acid nose was added to ozonation-treated water and the reaction was observed. The results shown in Figures 6 and 7 show that each sample water has a different amount of ammonia, iron, and manganese, so the amount of chlorine required is also different.For sample water A, which has a lot of ammonia, the amount of chlorine added was 1. FILj/l and Inukishi. As a result, regarding the production ability of TTI-(Δ4), even if the ozone injection rate and ozone contact time were increased for each sample water, the reduction effect was only about 20% compared to that without treatment. TTI at this time-
Looking at the increase and decrease in truffle 10 methane for each composition of TM, it is found that TO
Components with high chlorine content, such as M, BDCM, are reduced by ozone treatment, but TBM,
DBC! On the contrary, for components with a high bromine content such as M, there is a tendency to increase.

Next, when the effect of removing chromaticity by coagulation and precipitation treatment was investigated, the results shown in Figures 8 and 9 were obtained. According to this, the optimum pi (value is around 5 to 6) for coagulation for removing chromaticity, and the injection rate of sulfuric acid band is 10 to 20 at the above pH value.
■/l The chromaticity could be lowered to 5 degrees or less, which is the water quality standard value. However, in pII 7-8, 1oO
~120 m1iI/l was required, and sample water C did not fall below 8 degrees even if the injection rate was increased. When observing the state of these flocs with the naked eye, they are extremely fine, so-called micro-flocs, which are difficult to identify using the acidic range flocculation method, which has high color removal efficiency, and when using the neutral range flocculation method, the flocs are brittle and settle. Sex is extremely bad. 0.45 in the experiment
Although filtration is carried out using a μ millibore filter, it would be difficult to separate the flocs using an actual precipitation separation operation.

FIG. 10 shows the relationship between the chromaticity of raw water and filtrate water and the ability to produce 'I'TIIM, and there is a substantially linear relationship between the chromaticity and the amount of TTIIM produced. Judging from this figure, the Ministry of Health and Welfare's guidance target value for bird lometasi is 100μ.
To achieve y/L or less, the chromaticity must be reduced to 5 degrees or less.

Figure 11 shows the raw BX glare of TTlfM when 0.45 μm pore filtered water is mixed with unfiltered water. From this figure, if the coagulation and filtration treatment is insufficient, post-chlorination treatment is necessary. The production of torinohalomethane cannot be avoided, and it is expected that torinohalomethane will be produced from the flocs retained in the filtration layer due to the presence of chlorine.

From the above, ozone treatment is extremely effective in decolorizing, but it is not a drastic suppression measure against T'l'l1M generation when chlorine treatment is carried out afterwards, and mi: '1' =
Precipitation treatment is preferable if floc separation is ensured] Also, T'l
It has been found that the inhibitory effect on M production is significantly reduced if the amount of hydrogen is insufficient. In order to remove iron, iron, potassium permanganate, and other consumable substances in the water, chlorine injection is usually carried out, but chlorine injection is not recommended when chromaticity is present. This will lead to the production of trihalomethanes,
At present, it is difficult to remove this.

In order to solve the above-mentioned problems, the present invention removes dissolved substances in colored water using the oxidizing power of ozone, and also removes residual ozone by using a filter material having an active mankane dioxide catalyst coating, such as mankane sand or mankane. 'f' by utilizing the sublayer of electrolytic manganese dioxide particles
T) It provides a method to achieve the objective while suppressing IM.

As shown in Figure 1, this processing experimental equipment consists of two raw water tanks: 1. Raw water pump 2. Onn reaction tower 3. Manganese sand filter tower4. Treated water tank 5 and accompanying ozone generator 6. A sulfuric acid band injection device 7 is provided. Also, 8 is 03 meter, 9 is exhaust 03 tower, 10 is gas meter, 1
1 is a dehumidifier, and 12 is a compressor. In this example, the manganese sand filtration tower 4 uses an upward flow filtration method, so that the mixing and agglomeration of sulfuric acid is performed in the coarse particle filter layer 4a at the bottom of the filter tower, thereby saving on stirring and aggregation equipment. , etc. may be provided to perform normal downward flow filtration.

In addition, γ such as so-called electrolytic mankan dioxide can be used as a filter material.
When using a type manganese dioxide catalyst filter medium, the ozone injection rate can be easily controlled since it is possible to prevent manganese from becoming agglomerated by excess ozone and turning into heptavalent soluble manganese.

The raw water for this test was equal parts of the three ABC test waters. Manganese chloride is mixed in to increase the amount of dissolved mankan.

The treatment specifications were: treatment water concentration 311b, ozone reaction tower 3 residence time 10 minutes, ozone injection rate 12 my/l, and ozone air concentration 19/1. Mankan sand filter tank passivation conditions SV=
6'/h, LV=6 m/h, layer height 80 cm
sThe amount of post-chlorine injection into the treated water is 1 mg -Q
z/l (not shown).

The results of this processing are shown in FIG. According to this, not only can TTIIM, iron, mankan, chromaticity, permanganate consumption level, etc. be brought within the standard of tap water, but also the oxidation of non-oxidizing substances, raw water Because ozone is used for sterilization, it is possible to use chloramine, which has a weak branching reaction, when injecting chlorine to leave a residual chlorine residue, and therefore requires a long reaction time from the water treatment plant to the water tap. The presence of trihalomethane also has a great effect on suppressing trihalomethane production.

In addition, residual ozone was 2.8 in the population 4b of the manganese sand layer.
my/l was completely treated at the mirror layer outlet 4C, and the effect of catalytic decomposition of residual ozone was also confirmed. In addition, the amount of iron and manganese captured in the manganese sand layer in this experiment is consistent with that in the backwash water discharged from the sublayer during backwashing.
It was also confirmed that iron and manganese were converted into insoluble forms by ozone oxidation and captured in the substrata. In addition, in the experiment, we omitted the sulfuric acid band injection and performed direct filtration, but
There was no difference between this method and the microfloc method, partly because water flow time 1 was about 8 hours.

Table 2 shows a comparison of running costs between the conventional coagulation sedimentation filtration method and the ozone and microfloc method of the present invention. In addition to ozodi treatment and microfloc filtration using manganese sand, the combination of post-chlorination treatment that allows the use of combined chlorine is superior in terms of decolorization, iron removal, manganese removal, and suppression of tri-lomethane production, and the amount of sludge generated is small. Not only is it economical because a settling tank can be omitted, but the process is simple and maintenance efficient, and its utility value is remarkable.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an experimental device for implementing the present invention, FIGS. 2 to 11 are line diagrams showing the amount of increase and decrease in trihalomethane or the amount of decrease in chromaticity under each condition,
FIG. 12 is a line diagram showing the results when the method of the present invention is implemented. In addition, in the drawing, 1 raw water tank 2 raw water pump 3 ozone reaction tower 4 mankan sand filter tower 5 treated water tank 6 ozone generator 7 sulfuric acid band injection device. Fig. 1 Fig. 2 Fig. 4 Ozone injection rate [m9/)] Fig. 6 Ozone contact time (min) Fig. 7 Ozone/sweat entry rate (〒) Aggregation PH Fig. 9 A112 (504) 318820 (7 -) Figure 10 Chromaticity (degrees) Figure 11: Water procedure correction band (spontaneous) March 5, 1980 Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office■, Indication of the case 1988 Patent Application No. 14396 2 , Name of the invention Colored water treatment method 3, Relationship with the person making the amendment Patent applicant name Suido Kiko Co., Ltd. 4, Agent 5, Claims column 6 of the specification to be amended, Contents of the amendment ( (As shown in the attached sheet) (6. Contents of amendment) The claims in the specification (page 1, lines 5 to 13) are corrected as follows.

Claims (1)

[Claims] When treating colored water with chromaticity caused by humic substances such as humic acid, first a contact reaction treatment with ozone is carried out, and then
By adding a flocculant and performing flocculation treatment, and then filtering with a contact filter layer having a manganese dioxide catalyst film, the chromaticity of small and medium-sized particles, dissolved manganese and iron are removed, and the formation of trihalomethane is suppressed, and the formation of trihalomethane is suppressed. A colored water treatment method that is characterized by simultaneously decomposing residual ozone.