JPH0278488A - Complete treatment of waste water - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to an advanced treatment method for wastewater, and more specifically, to an advanced treatment method for wastewater that utilizes a chemical oxidation method that can significantly reduce the amount of chemicals used and maximize treatment capacity. Regarding processing method.

(Prior Art) Conventionally, in the removal of organic pollutant components in wastewater indicated by BOD, satisfactory results have been obtained at relatively low cost by various biological treatment methods currently in practical use.

On the other hand, for the treatment of organic pollutants present as COD (biodegradable substances, biometabolic waste substances, etc.), activated carbon adsorption method, ozone oxidation method, reverse osmosis method, chemical oxidation using oxidizing agents such as hydrogen peroxide, etc. methods are used.

Among these physicochemical removal methods, the chemical oxidation method using hydrogen peroxide and ferrous salt has an extremely strong treatment capacity and is an effective method for decomposing and removing a wide range of COD components in wastewater. Partially put into practical use (PPM-198
6/10: ] - see page 16).

However, even in the above chemical oxidation method using hydrogen peroxide, hydrogen peroxide,
Various problems remain, including the low consumption of iron salts and other chemicals used, and the processing costs.

For example, in this chemical oxidation method, when COD in waste water is oxidized and decomposed by adding hydrogen peroxide in the presence of an iron ion catalyst, the following reaction is performed.

Fe"+ II.0.-+ Fe"+ 110- +
110 - This reaction requires approximately the same mole of ferrous ion per mole of hydrogen peroxide.

The ferrous salt is usually ferrous sulfate heptahydrate (FeSO
4.71i20) is used, so for example, the usage rate is about 350 to 400 parts by weight per 100 parts by weight of 35% aqueous hydrogen peroxide solution. This ferrous salt is relatively inexpensive, but the generated ferric salt is later coagulated and precipitated by alkali neutralization, so the amount of alkali such as caustic soda used at that time, the amount of polymer-flocculant The disadvantage is that the amount of sludge used is high, and the amount of sludge containing ferric hydroxide as a main component is large, resulting in a high processing cost, resulting in a significant total processing cost.

The above-mentioned cost problem can be solved by removing COD before oxidation treatment when the concentration of COD in wastewater is relatively low.
Is it possible to avoid a considerable amount of OD by a method of coagulation and precipitation?C0Dfi in jJl water
COD of high degree and large size due to flat coagulation and sedimentation.
If it remains in the wastewater, the problem of cost still remains and it is difficult to use it economically.

In addition, the amount of hydrogen peroxide added is usually
It is O,l or twice as effective oxygen as fi, but
COD II in wastewater: 4 degrees often decreases to 5 o to 60%, and even if hydrogen peroxide is added to further reduce COD, it is difficult to reduce the COD further; on the contrary, residual peroxide The apparent COD of hydrogen when measuring CODfi degree
Detected as the value of Therefore, it becomes necessary to further add ferrous ions to remove residual hydrogen peroxide, which further raises the problem of increasing the cost of chemicals such as the alkali or polymer flocculant and the cost of sludge treatment.

Therefore, the first object of the present invention is to provide an advanced treatment method for wastewater that can achieve high treatment effects at low cost and with a small amount of chemicals used even if the CoDiQ level in the wastewater is extremely high. be.

(Means for Solving the Problems) In order to achieve the above object, the present inventors have conducted various studies and found that in a method for chemically oxidizing wastewater using an oxidizing agent, the reaction temperature at that time is increased, and as necessary, The present invention was completed based on the discovery that by adding other steps, excellent treatment effects can be obtained with a significantly lower amount of metal ions used.

That is, the present invention provides an advanced treatment method for wastewater in which organic pollutant components in wastewater are oxidized and decomposed with an oxidizing agent using metal ions as a catalyst, wherein the oxidative decomposition reaction is carried out at a temperature of 40°C or higher. This is an advanced treatment method for wastewater, and an acid coagulation treatment step, a catalyst regeneration step, or a biological treatment step is added before and after the advanced treatment method as necessary.

(Function) According to the research conducted by the present inventors, it was found that in the chemical oxidation method using hydrogen peroxide and iron salt, the decomposition and removal rate of COD was significantly improved by increasing the temperature of the wastewater to be treated. Ta.

However, when the COD concentration in the wastewater is relatively low, the energy cost required to raise the temperature of the wastewater is relatively high, so the cost advantage is not that significant, but when the COD concentration in the wastewater is high, It was recognized that the processing costs sufficiently absorb the energy costs, resulting in a significant overall advantage.

Therefore, it is even more advantageous when the waste water is heated waste water.

What's even more surprising is that when the temperature of the water to be treated is raised, the amount of iron ions used decreases by f11, whereas conventionally an equimolar amount of iron ions is required as hydrogen peroxide. A sufficient treatment effect can be obtained even at a usage rate of about 10-3 to 0.5 mol per 1 mol of hydrogen peroxide, and as a result, the amount of chemicals used afterwards, such as caustic soda and polymer flocculants, is reduced by f11. Furthermore, the amount of sludge produced was reduced by f11 in proportion to the iron salt used, and the processing cost was also significantly reduced. When these individual cost reductions are summed up, it has been found that the method of the present invention can reduce the cost to 1 of the conventional method by less than 8 minutes, especially less than the cost of the conventional method.

Furthermore, when performing the +2 method, 81 (and processing target jJ
By subjecting water to acidic coagulation treatment or using the used metal ions as catalysts11, drug use,
In addition, when the oxidized water is subjected to biological treatment afterwards, the biodegradability of COD, TOC, and BOD in the treated water is significantly improved, and in the subsequent treatment, the quality of the treated water, the load, etc. can be reduced. This makes it even more advantageous.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

Examples of wastewater to which the method of the present invention can be suitably applied include biologically treated human waste water containing 4T containing COD and color components, sewage leached from landfills, wastewater from waste incinerators, fermentation and brewing wastewater, highly concentrated organic wastewater, Petroleum, coal chemical wastewater, dyeing wastewater, metsuki,
Surface treatment wastewater, soluble oil wastewater, painting wastewater, and other CO
D is wastewater containing organic substances such as biorefractory substances and biometabolic waste substances indicated by chromaticity, etc., and can be applied to any conventionally known organic wastewater.

In particular, wastewater in which the effects of the present invention are particularly noticeable has a high concentration of COD and chromaticity components, for example, about 100+n as COD.
The wastewater has a concentration of 2 g/u or more, more preferably 4 g/u.
This is heated waste water that has already been heated to 0° C. or higher, and is particularly advantageous because heating energy costs are not required in the case of such heated waste water.

The oxidizing agent used in the present invention is an oxidizing agent used in conventionally known chemical oxidation methods, such as hydrogen peroxide, calcium peroxide, ammonium persulfate, alkyl hydroperoxide, peracid ester, dialkyl peroxide, or diacyl peroxide. is used, but hydrogen peroxide is most preferred in terms of cost and by-products. Hydrogen peroxide will be explained below as a representative example.

The amount of hydrogen peroxide used is not particularly limited and varies depending on the content of the applied wastewater, but the preferable amount is COD 10.
Approximately 50 to 8 o for 0 mg/H.

The range is mg/ρ (assuming 0).

The metal ions used in the present invention include iron, titanium, cerium, copper, manganese, Kohar I, vanadium, chromium, and lead ions, and any of these metals, metal oxides, metal salts, complexes, etc. It may be in the form of Particularly preferred in the present invention is iron ion, so iron ion will be explained below as a representative example.

Regarding the iron ions used, ferrous ions were used in the prior art, but in the present invention, ferrous ions as well as ferrous ions are effective, and metal iron such as iron scrap, iron ions, etc. Fixed iron ions fixed with ion exchange resin etc. can also be used.

An important feature of the present invention is that sufficient effects can be obtained with a significantly smaller amount of iron ions used as a catalyst than in the prior art. In other words, in the prior art, approximately an equivalent molar amount of ferrous ions (F
approximately 27 afltiit parts as eSO4, 71120)
However, in the present invention, a sufficient treatment effect can be obtained with approximately 10-3 to 0.5 moles per mole of hydrogen peroxide.

In the method of the present invention, the above-mentioned wastewater is heated and organic pollutant components in the wastewater are oxidized and decomposed using the hydrogen peroxide and iron ions, but the preferable range of the temperature of the wastewater in the present invention is 40°C to 40°C. 100°C, more preferably 50°C to 80°C
is within the range of If the wastewater has already been heated to the above temperature range, such as T hot water temperature wastewater, it is sufficient to simply maintain it at W, and no special heating is required. In the case of wastewater that has not been heated in advance, any heating means such as blowing in water vapor or heat exchange with other hot water in the T field can be used, and the heating method is not particularly limited. If the treatment temperature is less than 40° C., the oxidation efficiency will be insufficient and the efficiency of hydrogen peroxide utilization will deteriorate. Furthermore, if the temperature exceeds 80°C, no further treatment effect can be expected, and the self-decomposition of hydrogen peroxide is large, resulting in lower utilization efficiency and increased heating energy consumption, but there is no particular advantage. (See Figure 8).

Some preferred embodiments of the present invention utilizing the above-mentioned preferred conditions will be further described in detail with reference to the accompanying drawings.

The first diagram shows the basic method of the present invention (method according to claim 1)
An example is shown below.

The wastewater to be treated is heated to a suitable temperature through a first heat exchanger or by another heat source and led to a reaction tank, where it corresponds to a C0Di of 5 degrees in the wastewater! 11 iron ion catalysts 1. Add and mix 2 parts hydrogen peroxide and optionally 3 parts mineral acid, such as sulfuric acid, to adjust the pH of the wastewater to about 2-4. Incidentally, if the waste water is heated waste water at an appropriate temperature, heating is naturally unnecessary.

Preferably at 50 to 80°C while stirring in this reaction tank.
By performing oxidative decomposition at a temperature of about 0.01 to 5 hours, organic pollutant components in the wastewater are oxidized and decomposed to complete the reaction.

The treated water is optionally cooled in a second heat exchanger (cooler) (the heat absorbed here can be recycled in the first heat exchanger). The cooled treated water is preferably stored in a neutralization tank.
When the material is neutralized with an alkali 4 such as caustic soda at a temperature below 0° C. and the pH is adjusted to about 4 or higher, iron ions (mainly ferric ions) as a catalyst are precipitated in the form of flocs. This is led to a flocculation tank, for example, a polymer flocculant 5 is added and settled in the settling tank, and the sludge containing ferric hydroxide as a main component is collected from the bottom of the tank, and the treated water is discharged or This leads to another processing step.

Figure 2 shows a batch process in which the entire device is a tube.

In this example, heated wastewater is introduced after the reaction in the same manner as in the basic method, and 1 iron ion catalyst, 2 hydrogen peroxide, and 3 mineral acids are added thereto and oxidized in the same manner as in the basic method. and flocculant 5 are added and allowed to stand to coagulate and precipitate,
After separating the sludge, the treated water is discharged or directed to another treatment step. In this example, the above steps of mixing→reaction→neutralization→aggregation→precipitation→discharge are performed by timer or sequence control.

The example shown in the third diagram is an example in which a continuous reaction tower (or reaction tube) is used after the reaction in the basic method shown in the first diagram, and a catalyst carrier carrying an iron ion catalyst is fixed or fluidized in the reaction tower.
A predetermined amount of hydrogen peroxide 2 and mAe 3 are continuously injected into the waste water, which is heated by a heat exchanger or other heat source as necessary, and sent to the reaction tower for reaction. The treatment after the reaction may be the same as in the example shown in the first figure.

The example shown in FIG. 4 is an example (method according to claim 2) in which an acidic coagulation treatment step as a pretreatment step is added to the basic method shown in FIG. 1, and in this example, the wastewater to be treated is coagulated. This method is useful when a large amount of organic contaminant components that can be separated by a reagent is produced, and the amount of reagent used in the present invention can be further reduced. The above acidic coagulation treatment involves adding ferric ions to the wastewater in a range of 0.1 to 200mg/4 per wastewater COD density of 100mg/R, and adding mineral acid as necessary to adjust the pH to about 3.5. This is a method in which organic pollutants that can be coagulated and precipitated are separated as sludge by adjusting the concentration to 5.5 to 5.5 and adding a polymer flocculant or the like.

First, the wastewater is led to a mixing tank, where the pH is adjusted to about 3.5 to 55 by adding mineral acid 3 as necessary, and ferric ion 6, polymer flocculant 5, etc. are added. Organic pollutant components that can be coagulated and precipitated are coagulated, and the coagulated precipitate is separated using a sedimentation slurry. The excretory fluid is then sent to the process shown in the first diagram and treated similarly to the basic method shown in the first diagram. The ferric ions in the separated precipitate can be redissolved in acid and reused as a flocculant in the acidic flocculation treatment or as an oxidation catalyst in the basic method.

An example in which the above acidic flocculation treatment was actually used is shown below. That is, 400 rng/fl of ferric ions were added to automobile factory wastewater with a COD of 4 degrees and 2,900 mg/IL, and a mineral acid or alkali was added to change the pH during aggregation due to ferric ions, resulting in precipitation. The resulting sludge was separated and the COD of the supernatant water was analyzed, and the results shown in Figure 9 were obtained. As is clear from the results shown in Figure 9, the pH at the time of aggregation
The best flocculating effect is obtained in the pH range of 3.5 to 55, especially under weak acidity of pH 4, and at any pH outside this range, the COD of the upper ZN solution deteriorates.

Figure 10 shows the results when the pH was fixed at 4 and the amount of ferric ion added was varied in the range of 100 to 1.500 mg/l. The ferric ion used is C0D2, 900mz/
It turns out that 100 to 400 mg/U is sufficient for fl.

In addition, for wastewater that has been subjected to acidic coagulation treatment as shown below, the basic method shown in the first diagram above is carried out at 60°C with the addition of 1200 mg of catalyst.
The results obtained under 42 conditions are shown in FIG. FIG. 11 shows an example in which raw water was flocculated in a neutral state (pH=7) and an example in which the raw water was diluted 4 times as a comparison (1).

As is clear from FIG. 11, by subjecting half of the wastewater to acidic coagulation treatment, the treatment effect of the present invention becomes even more pronounced, and 2 fewer oxidizing agents and catalysts are used! Processing effects can be obtained in a roundabout and efficient manner. On the other hand, coagulation treatment under neutral conditions (pH = 7) showed a removal rate of about 70% compared to the conventional method, and if the wastewater was only diluted to a ton, organic substances that could be removed by coagulation were not present in the wastewater. As a result, the oxidation efficiency is insufficient compared to that obtained by adding acidic coagulation treatment.

As described above, in the present invention, by adding acidic flocculation treatment IP1 to the basic method of the present invention, the amount of chemicals such as oxidizing agents to be used can be reduced and the treatment efficiency is significantly improved.

Referring again to FIG. 1, an example of reusing the iron salt as a catalyst in the basic method (method according to claim 3) will be described. In the basic method shown in Figure 1, the sludge generated from the settling tank is mostly ferric hydroxide. In the method of the present invention, this ferric hydroxide can be reused directly as a slurry without being reduced to ferrous hydroxide or as a ferric salt after being dissolved in mineral acid as a catalyst during oxidation treatment. I discovered that. On the other hand, in the conventional method in which the oxidation reaction is carried out at room temperature, the ferric hydroxide recovered from the precipitation tank cannot be reused as an oxidation catalyst as it is, and when reused, it must be reduced to ferrous iron. It was necessary.

Therefore, in the method of the present invention, since there is no need to reduce the recovered ferric hydroxide, no chemicals such as reducing agents are required in this respect, and not only the cost of chemicals is significantly reduced, but also the amount of sludge generated is almost eliminated.

An example of reusing a catalyst is shown below. The waste water from the wiring pattern forming process of the printed circuit board was subjected to the acidic coagulation treatment described above, and the method shown in the first diagram was carried out, and the ferric hydroxide generated in the sediment was used as it was as a catalyst during the oxidation treatment. . In addition, for comparison purposes, in an example in which fresh ferrous salt was used as a new catalyst and in a conventional example in which oxidation treatment was performed at room temperature, the above ferric hydroxide, new catalyst, and recovered ferric hydroxide were mixed with mineral acid. An example was also carried out using a regenerated catalyst which was dissolved in water and reduced to a ferrous salt with sodium sulfite, and the results shown in FIG. 12 were obtained.

As is clear from FIG. 12, in the method of the present invention, ferric hydroxide exhibits an excellent catalytic effect that is almost the same as a new catalyst, and it is possible to reuse the ferric hydroxide as it is. On the other hand, in the case of the conventional method, if ferric hydroxide is used as it is, the catalytic effect is extremely low and it is necessary to reduce the ferric hydroxide to obtain a regenerated catalyst. That is, the method of the present invention not only requires less oxidizing agent, but also has the advantage that the ferric hydroxide recovered in the precipitation tank can be reused as a catalyst as it is, and no waste sludge is generated.

': jr, Figure 5 shows an example (method according to claim 4) in which a biological treatment method is added to the method of the present invention as described above.

Biological treatment is a process in which microorganisms ingest organic pollutants in wastewater as nutrients, decompose them to obtain energy, and use part of that energy to synthesize bacterial cells. BOD, TOC, CO in wastewater due to
This is a method for removing 7 cloudy substances represented by D, etc.

Biological treatment includes aerobic treatment and anaerobic treatment, and the former includes activated sludge method (continuous method and batch method), biological method,
There are oxidation pond methods and the like, and the latter is the so-called methane fermentation method, and any of these methods can be added to the basic method of the present invention to achieve excellent treatment effects.

Figure 5a shows that after chemical treatment according to the basic method shown in Figure 1, high-temperature fermentation (water temperature 53 to 5
Figure 5 shows a method of biological treatment in a methane fermentation tank at a temperature of 5°C. Figure 5 shows how the treated water, which has been chemically treated using the basic method shown in Figure 1, can be used as gray water from other systems or with some cooling without cooling. Figure 5C shows a method of biological treatment using a continuous activated sludge method after cooling by mixing with water. , Fig. 5d shows the most common method, the JT method, in which the water treated by the basic method is cooled to 40° C. or lower and then subjected to biological treatment in a contact aeration tank.

(Example) Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A chemical oxidation treatment of L pumped water was carried out using the process shown in the first diagram.

The COD concentration of the wastewater was 7.300mg/l, the wastewater was heated to 50°C, the pH was set to 3, the reaction time was 4 hours, the amount of catalyst added was fixed at 200mg/42, and the hydrogen peroxide concentration was When processing was carried out by changing the values, the results shown in Figure 6 were obtained.

Note that FeSO4,7H20 was used as a catalyst, and the amount and concentration thereof were expressed as FtH. Further, the amount and concentration of hydrogen peroxide used were also expressed as 0 (oxygen). The same applies to Izuwa below.

On the other hand, for the purpose of comparison, the wastewater was not heated, but was treated by the conventional method under the same conditions as above, except that the amount of iron ion catalyst added and the concentration of hydrogen peroxide were changed, respectively, at the same temperature as 15℃. The results shown were obtained.

Comparing this conventional method and the method of the present invention, the conventional method uses 25,000 mg/Jlj of iron ion catalyst and 10.0 mg/Jlj of hydrogen peroxide. OO0mg71104 degrees-1' COD Hough, 30-Omg/about 2,000mg/u from jZ
In contrast, in the case of the present invention, although the amount of iron ion catalyst is as small as 1/125 of the conventional method,
COD concentration ranges from 7,300mg/Jl to approximately 800mg/Jl
It dropped to 4.

In addition, the amount of catalyst and hydrogen peroxide required to reduce the CoDfA degree of the wastewater from 7,300 mg/u to 2,800 mg/IL was determined using the method of the present invention and the conventional method, and the results are as shown in Table 1 below. Therefore, the method of the present invention significantly reduces the consumption of catalyst and hydrogen peroxide compared to the conventional method.

γ La 1 - Fushi Hon Low -''-゛L Temperature (''C) 50 15 In addition,
In the method of the present invention, similar results were obtained even when ferric ions were used instead of ferrous ions as the iron ion catalyst, whereas in the conventional method, ferric ions had almost no effect.

Actual h'es Example 2 In this example, the same waste water as in Example 1 was used, but the fourth
Ferric ions 1. before treatment according to the illustrated process. OO
A chemical oxidation method was carried out using a material whose CoDfi degree was lowered to 4,700 mg/il by performing acidic coagulation treatment with O+ng/IL.

The temperature of the raccoon liquid to be treated was 50°C, the reaction pH was 3, and the reaction time was 4.
The catalyst was kept constant at 150 +++ g/u. As a result, the results shown in Figure 7 were obtained.

In addition, for comparison, the same treatment was carried out using the conventional method at a temperature of 15°C and with different amounts of catalyst and hydrogen peroxide concentration without heating the water to be treated, and the results shown in Figure 7 were obtained. .

Comparing the method of the present invention and the conventional method, in the case of the conventional method, the catalyst amount was 10,000+
At a hydrogen peroxide concentration of ng/42, the COD concentration is 4.700.
+ng/R to about 1,700 mg/l, whereas the method of the present invention uses 1/167th the amount of catalyst and C0Di5 degree from 4.700 mg/fi to about 500 mg/'! It decreased to 1.

In addition, in Figure 7, the hydrogen peroxide concentration is 3,000 mg/'
The biodegradability of the treated water of the present invention and the conventional method obtained in Q was investigated.

Using the above-mentioned treated water diluted 20 times as raw water for the biodegradability test, the biodegradability test was conducted under the same conditions for both the present invention and the conventional method, and the results shown in Table 2 below were obtained.

γ-J 2 j-mi Conventional method 90 135 120 Invention
75 120 95 Conventional method 31 (65,6
) 52(64,1) 5(95,8) Present invention
+3 (82,5) 25 (78,9) 2 (97
, 5) (The value in parentheses represents the percentage of biodegradation relative to the raw water.) From the above results, it is clear that the treated water obtained by the method of the present invention has excellent biodegradability, and it is clear that the treated water obtained by the method of the present invention has excellent biodegradability. By using biological treatment methods, better wastewater treatment is possible.

In addition, in the method of the present invention, similar results were obtained even when ferric ions were used instead of ferrous ions as the iron ion catalyst, whereas in the conventional method, ferric ions had almost no effect.

Example 3 In this example, the decrease in COD concentration due to the temperature of wastewater was investigated.

Catalyst was added at 200 mg/I1. to the water to be treated with the same C0Dfi degree of 4,700 mg/L as in Example 2. , 2.5 hydrogen peroxide
When the COD concentration was added at a concentration of 00+ng/H and reacted for 1 hour at various temperatures to determine the change in COD concentration, the results shown in FIG. 8 were obtained.

As is clear from Figure 8, the decrease in COD concentration is small up to 40°C, and as the temperature rises to 40°C or higher, the COD concentration decreases.
If the iJ degree suddenly decreases to about 50℃ or higher, there is insufficient C.
A decrease in OD concentration was observed. Therefore, in the present invention, it is most preferable to set the reaction temperature to 50°C or higher.

Example 4 In this example, the method shown in Figure 1 was used to perform COD treatment of cutting oil wastewater at a factory, and the cost was calculated.

匪水Ω and base water jet: 20
rr? /day water temperature:
15℃ COD concentration: 700mg/
l COD of treated water: 100 mg/Q Inventive method: Temperature and heat retention at 50°C by live steam injection.

Conventional method: The temperature remained at 15°C without increasing the temperature).

γ 3 Knee 11□0□ 35% liquid +20 607
72,840FeS04'711゜0, 25
20 500112So, 98%7
night 20 1
2ONaOH97% flakes 1
20 5.7 58
4 Kerosene (for heating) 60 yen/fl 6on/day 3
．． 600 total --79,939
is processing unit cost 3,99711□0
235% liquid +20 728 87,360
FeSO, -711゜0 25 1,800
45.000II2So49B% solution 20
0 0NaOII 97'! flake
120 514 6
1.6110 Kerosene (for heating) 60 yen/I1. l/day
0 total -2
71,440 is the processing unit price 1:I,
As shown above, the method of the present invention reduced the processing cost by about 30% compared to the conventional method.

Example 5 This example uses the method shown in FIG.
COD treatment of wastewater (80°C) was performed and cost calculations were performed.

Prefectural tree @ Kashiwa Ut: 120rr?
COD concentration: 7,20.0 [I1g/Q-treated water COD: 2,000+ng/Il'7-
4 y-=z +1,02 35% liquid 120
2.914 349.680FcC1340
° Bci night 8 2,290
+8.32ONa011 50% liquid:]
0 1,286 38.580 total
--561,380 is processing unit cost -4,
678 +1202ff 5% liquid 120
7.286 874.32゜FeSO4・7
t120 15 15. (10022
5, QQONaOH50%fi 30
8,571 257.130 total
--2,091,750 is processing unit cost -17.4
31 As described above, the processing cost of the method of the present invention was reduced to about 27% compared to the conventional method.

(Effects) As described in 1-1 below, according to the present invention, according to the research of the present inventors, by increasing the temperature of the wastewater to be treated in the chemical oxidation method using hydrogen peroxide and iron salt, It was observed that the decomposition and removal rate of COD was significantly improved.

However, when the concentration of COD in wastewater is relatively low, the energy cost required to raise the temperature of 18 water is relatively high, and the cost benefit is not that great.
It has been found that when the CODa degree of wastewater is high, the treatment cost sufficiently absorbs the energy cost and becomes significantly advantageous overall.

Therefore, it is even more advantageous when the waste water is heated waste water.

What is even more surprising is that when the temperature of the water to be treated is raised, the amount of iron ions used decreases by +11, whereas conventional methods require iron ions that are almost the same as hydrogen peroxide. A sufficient treatment effect can be obtained even at a usage rate of approximately 0.5 mole of 10-J per 1 mole of hydrogen peroxide, and as a result, the amount of agents such as caustic soda and polymer flocculants used afterwards is drastically reduced. Furthermore, the size of the slough produced was drastically reduced in proportion to the amount of iron salt used, and the processing cost was also significantly reduced. It has been found that when these individual cost reductions are summed up, the cost of the Kerr method of the present invention is less than half that of the conventional method, particularly less than half of that of the conventional method.

Furthermore, when carrying out the above method, the use of chemicals can be further reduced by subjecting the I41 water to be treated in advance to acidic coagulation treatment or by reusing the used metal ions as a catalyst. In the case of biological treatment, the biodegradability of COD, ToC, and BOD in the treated water is significantly improved, and the subsequent treatment becomes even more advantageous in terms of treated water quality, load, etc.

[Brief explanation of the drawing]

FIGS. 1 to 5 show flow sheets showing preferred embodiments of the present invention, and FIGS. 6 to 12 are diagrams showing processing results in Examples. 1 Catalyst 2. Hydrogen peroxide 3: W, acid
4: Alkali 5: Polymer flocculant 6
Ferric ion 7jTJ11S0 Hawk Deaf 5o-80℃ Fig.5 Gas (biofilm treatment shell) Figure 9: %H Figure 10: Fe:l ′'' (simple 8)' cross) Figure 11

Claims (7)

[Claims] (1) An advanced wastewater treatment method in which organic pollutant components in wastewater are oxidized and decomposed with an oxidizing agent using metal ions as a catalyst, characterized in that the oxidative decomposition reaction is carried out at a temperature of 40°C or higher. . (2) In an advanced wastewater treatment method in which organic pollutant components in wastewater are oxidized and decomposed with an oxidizing agent using metal ions as a catalyst, the wastewater to be treated is subjected to acid coagulation treatment, and then the oxidative decomposition reaction is carried out for 40 minutes.
An advanced wastewater treatment method characterized by carrying out the treatment at a temperature of ℃ or higher. (3) In an advanced wastewater treatment method in which organic pollutant components in wastewater are oxidized and decomposed with an oxidizing agent using metal ions as a catalyst, the oxidative decomposition reaction is carried out at a temperature of 40°C or higher, and the generated metal ions are recovered and recycled as a catalyst. An advanced wastewater treatment method characterized by the use of (4) In an advanced wastewater treatment method in which organic pollutant components in wastewater are oxidized and decomposed with an oxidizing agent using metal ions as a catalyst, the oxidative decomposition reaction is carried out at a temperature of 40°C or higher, and the treated water is subjected to biological treatment. Features an advanced treatment method for wastewater. (5) COD concentration in wastewater to be oxidized is 100mg/
5. The advanced treatment method for wastewater according to claim 1, wherein the amount of waste water is 1 or more. (6) The oxidizing agent is hydrogen peroxide, and the added concentration (assuming 0) of the hydrogen peroxide is 5 per 100 mg/l of COD concentration.
The method for advanced treatment of wastewater according to claims 1 to 4, wherein the concentration is in the range of 0 to 800 mg/l. (7) The metal ion is a ferrous ion and/or a ferric ion, and the concentration of these iron ions (as Fe) is 1 to 200 m per 100 mg/l of hydrogen peroxide (as 0).
The advanced treatment method for wastewater according to claims 1 to 4, wherein the wastewater is in the range of g/l.