JP3526143B2 - Advanced wastewater treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention
Min, nitrogen components such as ammonia nitrogen and nitrate nitrogen, water soluble
Treatment method for wastewater containing phosphorus components such as basic phosphate
And more specifically, through multiple processing steps.
Each of the above components to a level that can be discharged into sewage and rivers
Advanced wastewater treatment method that can reduce the content of water
Related. [0002] 2. Description of the Related Art Conventionally, wastewater having a high BOD concentration is dumped in the ocean.
Has been approved and many of such waste liquids are disposed of by ocean dumping.
Relied on disposal. However, waste, other
London Convention on marine pollution from dumping 199
Marine dumping is prohibited from January 2006, and BO in wastewater
Each concentration of D, TN (total nitrogen) and TP (total phosphorus)
Reduce each to below the specified concentration and release to sewage and rivers
Will be obliged to do so. [0003] BOD component, nitrogen component and phosphorus component in wastewater
Separately treat these components and remove these components from wastewater or
Various methods have been studied and implemented in the past.
However, by combining each method, continuously and
Methods for efficient processing are almost unexamined. [0004] Under such a background,
Continuously treat wastewater, such as waste liquid that had previously been dumped in the ocean,
BOD, TN and TP are reduced to below specified levels or low
There is an urgent need to develop ways to reduce it. Therefore,
The purpose of Ming is to increase the concentration of BOD components, ammonia nitrogen,
Nitrogen components such as nitrate nitrogen and organic nitrogen, various water-soluble phosphorus
Continuous treatment of wastewater containing phosphorus components such as acid salts
Is to provide a way. The present inventors diligently studied
As a result, by combining certain processing methods,
Not only is it possible to treat wastewater efficiently, but also
See how the compact footprint saves space
I came out. [0005] The above object is achieved by the present invention which is described below.
Reached by Ming. That is, the present invention provides a high BOD
Wastewater containing water, nitrogen, phosphorus, etc.
Step of stripping ammonia nitrogen (1), nitric acid
(2) biologically treating nitrogen, BOD and / or
Or the step of treating organic nitrogen with activated sludge (3);
Step (4) of chemically oxidizing near nitrogen and phosphorus component
The step (5) of coagulating and precipitating theThrough the above orderProcess
This is an advanced method for treating wastewater. [0006] BEST MODE FOR CARRYING OUT THE INVENTION
The invention will be described in detail. The wastewater applicable to the present invention is particularly
Not limited, high concentration of BOD component, nitrogen component, phosphorus component
Any wastewater containing such can be treated.
Before the treatment by the method of the present invention, the wastewater to be treated is neutralized.
Pretreatments such as treatment and removal of solids are carried out as necessary
It is desirable to do. The feature of the present invention is that
Is also processed in a step including the above steps (1) to (5).
However, according to the quality of wastewater to be treated,
That the process can be performed in any order.
You. First, in each step of the present invention, wastewater is treated.
The case where steps (1) to (5) are processed in numerical order
An example is briefly described below. In step (1), the
Ammonia by stripping ammonia nitrogen
This is the step of removing. Step (2) is stripping
Anaerobic treatment with activated sludge to remove nitrate nitrogen
Is a process of decomposing into nitrogen gas. In step (3)
Is aerobically treated with activated sludge to separate organic nitrogen and BOD.
Understood. In the step (4), the ammonia generated in the step (3)
This is the step of oxidizing near nitrogen and removing it as nitrogen gas.
You. By performing this step, coagulation and precipitation cannot be performed.
Coagulation and precipitation of phosphorous acid, hypophosphorous acid and their salts
It will be easier. In step (5), it is not removed in the above steps
Phosphorus component is removed by coagulation and precipitation by adding coagulant
I do. The wastewater (treated water) treated in the above process is
Released into sewage or rivers as pollutants are reduced
However, when discharged into rivers, treated water
Pay attention to the pollutant concentration of
It is preferable that the water is discharged into a river after the water is applied. Next, in each step, ammonia nitrogen,
Wastewater containing nitrate nitrogen, BOD component and phosphorus component
Water) is processed through steps (1) to (5) in numerical order.
FIG. 1 is a flowchart illustrating an example of the present invention.
You. (1) Ammonia stripping process In order to increase the efficiency of removing ammonia nitrogen in wastewater,
The wastewater is made alkaline with caustic soda, etc., preferably
It is adjusted to 10-12. Wastewater pH is in this range
Wastewater can be used as is without pre-neutralization treatment
Noh. Wastewater whose pH has been adjusted to alkaline
Steam, heated air, etc.
Is further heated to strip ammonia gas
You. Stripping temperature is the concentration of ammonia in wastewater
It is preferably 60 to 100 ° C
You. Preferred stripping column used in this step
Are tray towers and packed towers, but ammonia gas is more efficient.
There is no particular limitation as long as the column is stripped well.
No. The operating conditions of the column are not particularly limited. The stripped ammonia gas is
Usually, it is neutralized or oxidized.
Acids that can be released into the atmosphere as nitrogen gas without problem
Treatment is preferred. Ammonia gas oxidation treatment method
In the presence of a known oxidation catalyst such as platinum or rhodium.
There is a method to oxidize and decompose ammonia gas into nitrogen gas and water.
You. Preferred oxidation temperatures are between 250 and 400 ° C. other
There is also a method of burning in a boiler as an oxidation treatment method
You. On the other hand, the stripped wastewater is as follows:
Is sent to the nitrate nitrogen removal process of
Exchange with wastewater (raw water) that is newly stripped
After being changed, it is sent to the next process. Ammonia nitrogen
Decomposes into nitrate nitrogen by nitrifying bacteria under biologically aerobic conditions
And further separated into nitrogen gas by denitrifying bacteria under anaerobic conditions.
This method is generally used, but the reliability of treatment and aeration
The site area required for installation of tanks etc. is large,
I can't say. However, stripping in this process
Removes virtually all of the ammonia nitrogen
It is. In addition, the area with less installation of stripping columns
The advantage of ending is also great. (2) Biological treatment of nitrate nitrogen The wastewater from which ammonia nitrogen has been removed is subjected to anaerobic treatment in this process.
Under the circumstances, it was biologically treated with denitrifying bacteria and
Released into the air. For anaerobic denitrification treatment, conventionally known raw
Any physical anaerobic treatment method can be used,
Small area and high concentration of sludge
Fluidized bed anaerobic water treatment device capable of load operation (upward flow type
Sludge blanket type equipment).
New PH of wastewater is adjusted to 6.0-8.5 during treatment
Is done. In this process, the wastewater is high salt concentration wastewater.
However, stable and efficient removal of nitrate nitrogen is possible.
You. FIG. 2 shows an example of a fluidized bed type anaerobic water treatment apparatus.
Show. 1 is a denitrification tank. The wastewater to be treated is the raw water inflow pipe
The raw water is sent to the raw water receiving section 3 from the pipe 2, and the raw water flows down the pipe 4
And supplied into the denitrification tank. In the lower part of the stirrer shaft 4
Upward flow of treated wastewater and sludge settling in the denitrification tank
The turbine blades 5 that rise inside the denitrification tank as
The paddle blade 6 for sludge stirring is attached to the upper part.
You. This stirrer shaft 4 is rotated by a variable stirrer 7.
The treated wastewater rises to the treated water collecting section 8 and is discharged.
It is discharged from the mouth 9. 10 is a sampling tube, 11 is dirty.
A mud drain port, 12 is a drain outlet, and 13 is a denitrification tank 1.
It is a stand to be fixed. [0013] In the wastewater treated by this device, Ca²⁺Contains
If it is, remove it in the tank as described below.
CaCO formed_ThreeThe denitrification sludge is granulated with
This is a particularly preferable method because the processing efficiency can be improved. still,
Ca²⁺Is not contained in the treated wastewater
Indicates that Ca²⁺Add source material
Thus, highly efficient processing is possible. Ca in wastewater²⁺The amount of
It is at least 500 mg / l. That is, the waste water to be treated passes through the raw water downflow pipe 4.
It is supplied to the lower part of the denitrification tank 1 and rotates the turbine blades 5.
Therefore, it becomes upward flow and rises in the denitrification tank 1,
Contact with denitrification sludge. Dissolved carbon dioxide in wastewater to be treated
Is Ca²⁺Reacts with CaCO₃Generate Denitrification
The sludge is made of CaCO₃Granulated with the core
Nitrate is denitrified by granulated denitrification sludge
To produce nitrogen gas. [0015] Since the granulated denitrification sludge has a high density,
Sludge by nitrogen gas generated by denitrification of acid nitrogen
Is prevented from rising to the top of the denitrification tank, and sludge is
To denitrify nitrate nitrogen. The denitrification sludge in the denitrification tank is treated under stirring.
Contacting with the wastewater, but stirring was attached to the stirrer shaft 4
This is performed by the stirring paddle blade 6. Granulation of denitrification sludge
A preferable stirring condition to be promoted is that the peripheral speed at the tip of the stirring blade is
The range is 3 to 30 cm / sec. The wastewater to be treated is supplied directly to the lower part of the apparatus.
Often, means to make treated wastewater upward flow is also used for turbine blades.
Methods other than rotation, for example, supply of wastewater to be treated by a pump
Means such as feeding may be used. Drainage is 0.4-3.0m
/ Hr Adjust the inflow speed so that the flow is upward
However, it is preferable to contact with denitrification sludge. Also, denitrification
When stirring the sludge, the peripheral speed at the tip of the stirring blade is within the above range.
The shape, type, number, etc. of the stirring blades are especially
Not restricted. The initial seed denitrification sludge concentration (MLS) in the denitrification tank
S) is usually 5,000 to 15,000 mg / l
You. The sludge partially settles at the bottom of the tank, but the wastewater to be treated
Ascending with the upward flow. Sludge and wastewater to be treated under stirring
, Wastewater to be treated is treated by denitrification etc.
The treated wastewater is collected at the top of the tank.
And the nitrate nitrogen was removed from the treated water outlet
It is sent to the next step as treated water. In this step, nitrate nitrogen is removed, and the
Fruit BOD component also decreases, but organic nitrogen is removed or reduced
Therefore, these components are removed or reduced in the next step.
Work. (3) Activated sludge treatment process The amount of BOD components and organic nitrogen remaining in the wastewater in this process
Perform solution processing. Conventionally known aerobic activated sludge treatment
Both methods can be used, and processing in a completely mixed aeration tank is
Is typical, but avoids the occurrence of bulking
It is difficult. Prevents bulking and high salt conditions
BOD component and COD component are stable and efficient even under
The following processing methods that can be processed are particularly suitable. That is, a plurality of aeration tanks connected in series or
Or supply drainage to an aeration tank divided into multiple compartments,
Wastewater is transferred from the inflow-side aeration tank to the outlet-side aeration tank in sequence.
As the BOD of wastewater gradually decreases gradually
It is a method of processing. The capacity of the aeration tank depends on the amount of wastewater to be treated and
Can be appropriately selected according to the BOD component concentration, etc.
There is no particular limitation. The capacity of the aeration tank is the same for all aeration tanks.
One capacity, different capacity, and the same
It is possible to use a product with a capacity different from the capacity.
I don't know. At least two aeration tanks connected in series
As mentioned above, the larger the number of treated wastewater
Is desirable. It is difficult to prevent bulking with less than 2 tanks
You. Preferably 3 to 10 tanks. As the aeration tank, any conventionally known aeration tank can be used.
Can be used and is not particularly limited.
Eliminates and has anti-bulking effect itself
A deep tank type aeration tank, which is a well-type aeration tank, is a preferred aeration tank.
It is mentioned. The deep tank type aeration tank has an outer cylinder having a bottom and an outer cylinder.
An inner cylinder having upper and lower open ends provided inside
Drainage and active water introduced from the upper end of the inner cylinder (downward section)
Activated sludge descends in the cylinder and reaches the lower end.
The mixed liquid of mud rises in the gap between the two cylinders (rising part),
The descending part so that a circulating flow that repeats descending and ascending is formed
And sends air to the ascending section, and descends after a circulating flow is formed
Supplying air only to the section and aerating
Processing is performed. According to this method, activated sludge organic
Another advantage is that the processing speed is fast and bulking is prevented.
You. In the case where a deep tank type aeration tank is used in the present invention,
Has the same basic structure as above, but the depth is
Depending on the amount of wastewater and the concentration of BOD components in the wastewater,
It may be determined appropriately, and is not particularly limited. For example, 20
It is about 100 m. Next, the difference in the BOD component concentration between the aeration tanks is calculated as follows.
The BOD component concentration in the water is increased in the first and second aeration tanks.
And the BOD component concentration in the raw wastewater is reduced by 80-95% by weight.
(The concentration of BOD component after treatment is lower than that of raw wastewater.)
Concentration of 20 to 5% by weight).
Good. In the aeration tank after the third tank, settle the sedimentation tank.
BOD concentration of treated water discharged from
The BOD component concentration may be reduced step by step as follows.
However, in any aeration tank, the BOD component concentration
Treated so as to be 50% by weight or less of the concentration in the aeration tank
Is preferred. The concentration gradient of the BOD component as described above is initially
~ The method provided between the last aeration tanks is not particularly limited.
However, for example, a method of providing an activated sludge concentration difference between aeration tanks,
The activated sludge concentration in each aeration tank is determined by the standard activated sludge method.
Same as above, but the residence time of wastewater in each aeration tank
(Treatment time), activated sludge concentration difference and residence time
There is a method of combining the differences, and the like. Examples of the method for providing the activated sludge concentration difference are as follows.
For example, when connecting three or more aeration tanks, the first aeration tank
The mixture in the last aeration tank after the third tank is returned to the
The returned sludge from the tank is returned to the second aeration tank,
Activated sludge concentration (MLSS) of air tank is 100-1000m
g / l is particularly preferred.
However, part of the sludge returned from the settling tank is
The same applies to the method of returning the rest to the second aeration tank.
The same effect can be obtained. As a method of changing the residence time, for example,
The capacity of the first and the next aeration tanks is 1/10 of the capacity of the entire aeration tank.
Method, etc., but this method also requires B
An OD concentration gradient can be provided. The effluent treated and discharged from the last aeration tank is sedimented
Sent to a tank where it is separated into activated sludge and supernatant water.
The clear water is sent to the next step. Activated sludge is partially returned
Returned to the aeration tank as mud. Wastewater is biodegradable
If it contains organic substances, the treated water will be further chemically oxidized.
Processing using other processing methods such as
The OD component concentration can be reduced to a predetermined concentration.
By the treatment in this step, organic nitrogen is converted to ammonia nitrogen.
It is decomposed into elements and removed in the next step. (4) Step of oxidizing and removing ammonia nitrogen In this process, the ammonia nitrogen generated in the previous process is oxidized
Treated and released into the atmosphere as nitrogen gas. Oxidation treatment method
As the treatment with oxidizing agent, photo-oxidation or ozone acid
There is a treatment that does not use an oxidizing agent such as
Oxidation treatment method capable of oxidizing nitrogen from nitrogen
Any of them can be used. A typical example of an oxidation treatment method using an oxidizing agent is as follows.
Uses oxidizing agents such as hydrogen peroxide and metal ions such as iron ions
Oxidation by known chemical oxidation method (Fenton method)
Processing. As the oxidizing agent, for example, hydrogen peroxide,
Sodium chlorite, calcium peroxide, ammonium persulfate
, Alkyl hydroperoxide, perester,
Dialkyl peroxide or diacyl is used.
Hydrogen peroxide is most preferred in terms of heat and by-products.
No. As metal ions, iron, titanium, cerium, copper,
Manganese, cobalt, vanadium, chromium and lead ions
Are used, these metals, metal oxides, metal salts, complex
Any form such as a body may be used. Particularly preferred are the first
Iron ion (usually FeSO₄・ 7H₂O is used)
is there. The amount of hydrogen peroxide used is usually
(As O) in the range of 10 to 700 mg / l,
The amount of ON is usually 30 to 12 (as Fe) as iron.
It is in the range of 00 mg / l. The oxidation treatment is usually 5 to 7
The reaction is performed at 0 ° C. for about 5 to 60 minutes. The pH of the wastewater is
Generally, it is adjusted to about 2 to 4. The treatment by another chemical oxidation method uses an oxidizing agent.
This is a method using hypochlorite. Hypochlorite
For example, sodium, potassium, potassium
Alkali metal salts such as lucium, alkaline earth metal salts, etc.
Used, but sodium hypochlorite is the most typical
You. Oxidation treatment with hypochlorite increases the pH of wastewater by caustic
Adjust to about 7-9 by adding alkali such as soda,
This is performed at about 70 ° C. for about 5 to 60 minutes. Hypochlorite
Used amount is about 20-1000mg / l as available chlorine
Degrees. In terms of processing reliability, hypochlorite
An oxidation treatment is preferred. Ammonia nitrogen is oxidized in this process
It is released to the atmosphere as nitrogen gas. Wastewater (raw water) contains organic nitrogen
If this is not possible, this step can be omitted.
If the following reduced phosphorus component is present as
Is omitted in the next step (5).
It cannot aggregate and precipitate. Therefore, in raw water
Even when organic nitrogen is not contained, as a phosphorus component
This step is necessary if a reduced phosphorus component is present
It is. (5) Aggregation and precipitation step of phosphorus component The last step is to remove the remaining phosphorus components by adding a flocculant.
This is the step of removing by coagulation and precipitation. Removal of phosphorus component
The activated sludge method has been used for the treatment,
Is a preferred treatment method because the removal rate fluctuates greatly due to
hard. In addition, the phosphorus component is a salt of orthophosphoric acid (orthophosphoric acid).
Forms a poorly water-soluble phosphate when present in the form
Precipitation by adding a cationic flocculant
Possible, but phosphorus is reduced form such as phosphorous acid or hypophosphorous acid
The so-called coagulation treatment described above when present in the form of a phosphorus compound
Removal is virtually impossible. However, in this step, the starting
Phosphorus component in wastewater (raw water) is phosphorous acid, hypophosphorous acid, etc.
And their salts are oxidized in the previous step
Aggregation of these phosphorus components by the addition of a flocculant,
It can be precipitated. In other words, in the oxidation process of the previous process
Therefore, reduced phosphorus (H₂PO^2-, HPO_Three ^2- ) Is oh
Lut type phosphorus (PO_Four ^3- ) Is probably oxidized
You. In the coagulation treatment in this step, the coagulant is added with a phosphorus component.
Phosphorus component coagulates and precipitates by adding to wastewater.
And removing it as a solid. As a flocculant
Are known cationic and inorganic flocculants.
Can be used, and by using them together,
Effective processing is possible. As the inorganic coagulant, sulfuric acid
Ban earth, basic aluminum chloride (for example, polychlorinated aluminum chloride)
Lumi PAC etc.), and acrylic polymer
Amide polymer, polyethyleneimine, polyamine
Piclohydrin condensate, alkylaminoethyl methacrylate
And the like. These coagulants have the maximum coagulation effect.
Use the pH of the wastewater to be treated.
To the optimal pH for the flocculant
is necessary. The amount of the flocculant used is not particularly limited.
Depends on the concentration (TP) of the phosphorus component in the treated wastewater.
However, the concentration of the phosphorus component in the treated wastewater is
It is necessary to use the amount below.
You. The method of coagulation and precipitation includes coagulation and precipitation.
Separation and sedimentation separately, rapid coagulation sedimentation
Di-blanket type coagulation sedimentation equipment, sludge circulation type coagulation sedimentation
Aggregating and sedimenting at the same time using
Or agglomeration and then precipitation with a rapid sedimentation device.
However, is it possible to reduce the installation area and achieve efficient sedimentation?
It is preferable to use a rapid coagulating sedimentation device or a method using a rapid sedimentation device.
Suitable. Through the above-described processing steps, the exhaust
BOD, nitrogen and phosphorus in water are removed below a certain concentration.
The treated water can be discharged into rivers or sewage.
You. The above uses all of the steps (1) to (5).
This is an explanation of wastewater treatment.
Depending on the quality of the water, one or more unnecessary steps may be
More can be omitted. If necessary,
Process, such as activated carbon treatment of treated water.
You can also match. Also, the order of processing steps is
It is not necessary to perform (1) to (5) in numerical order;
Each processing should be performed in the order that can be processed efficiently according to
In addition, the order of the steps is not limited. [0043] The present invention will now be described in more detail with reference to the following examples.
explain. Example The wastewater (raw water) of the water quality shown in Table 1 was processed in the following treatment steps.
Processed. (1) Ammonia stripping process Ammonia in raw water using a packed tower filled with Raschig rings
Near stripping was performed. PH 1 with caustic soda
Preheat raw water adjusted to 0.5 to 80 ° C (stripping)
After the start, treated wastewater discharged from the column is transferred to the heat exchanger.
Preheat the raw water) and at a rate of 20 to 30 m / hr
It is supplied to a packed tower and stored at 100 ° C with an L / G ratio of 8-12.
Ripping was performed continuously. During the draining of the stripping column out
Ammonia is not detected and ammonia removal rate is substantial
Was 100%. Stripped ammonia
The gas was burned in a boiler. Flat in column-out drainage
The water soaking quality is shown in Table 5 below. [0045] [Table 1](2) Biological treatment of nitrate nitrogen Anaerobic aeration device shown in Fig. 3 (upflow sludge blanket)
Treatment of wastewater from the stripping column
Was done. The pH was adjusted to 7.5-8.0. Glass
The cylindrical reactor has a diameter of 8 cm and a straight body length of 77 c.
m (volume is about 4 liters), length of sedimentation area is 26cm
(The volume is about 2.5 liters). Rotary axis in reactor
, Two mesh-shaped stirring blades are installed in four stages, and the peripheral speed is
Rotate with a motor (M) so that it becomes 10 cm / sec.
Let The waste water to be treated in the raw water tank is pumped (P
₁) Will cause an upward flow of 0.6 m / hr at the bottom of the reactor
At a rate of 36 liters / day. processing
The treated water that has risen to the sediment
It is sent to the treated water tank, and part of the treated water in the treated water tank is pumped.
(P₂) So that the same upward flow as above occurs at the bottom of the reactor
Supplied to [0048] Sludge containing denitrifying bacteria (Kimitsu Futtsu terminal treatment plant
Waste sludge) is discharged from the above stripping column
It was used after it had been fully acclimated to the drainage water. First sludge
Phase MLSS (the amount of activated sludge in the mixed solution) and VSS (mixed
The amount of microorganisms in the liquid) is 8000 mg / l and
Adjusted to 6,400 mg / l. The treatment of the water to be treated is performed at 30 ° C.
For 60 consecutive days. Average ML in continuous processing
SS, average VSS, average NO₃-N removal rate, average removal
g-MLSS / day, average removal g-NO₃-N / g-
Table 2 shows VSS / day. Average water of treated wastewater
The quality is shown in Table 5. [0050] [Table 2] (3) Biological BOD decomposition treatment Multiple aeration tanks connected in series to wastewater from which nitrate nitrogen has been removed
And performed a process to gradually reduce the BOD In this step, two 5-liter aeration tanks
(Aeration tanks I and II) and 50 liters of completely mixed aeration
Activated sludge treatment bench consisting of a tank and a 25-liter sedimentation tank
The plant was connected. BOD volume load 0.6kg
-BOD / m³-Processing was performed on day. First day of processing
Activated sludge concentration and BOD concentration in each aeration tank on day 28 and 28
Table 3 and Table 4 show the first to 35th days of the treatment according to this step.
Average SS, BOD, of treated water discharged from the settling tank,
SV₃₀And SVI, and Table 5 shows the average water quality. This example
Then, the entire amount of returned sludge from the sedimentation tank is sent to the first aeration tank.
Sent back. [0053] [Table 3] [0054] [Table 4] (4) Oxidation treatment step Wastewater containing ammonia nitrogen from the precipitating settling tank
Was oxidized using sodium hypochlorite. Hypo
In the treatment with sodium chlorate, the pH of the wastewater is set to 8,
5 liter capacity with stirrer at 960 liters / day
The mixture is supplied to the reaction tank, and the residence time (reaction time) becomes 7.5 minutes.
Adjust the amount of effluent so that the available chlorine is 1200mg
8 liters of aqueous solution containing per liter of sodium hypochlorite
/ Day at 35 ° C. Effluent after reaction
Send to a reaction vessel with stirrer of the same volume as above,
Um (Na₂SO₃) To eliminate residual chlorine
And also removes residual sodium sulfite by aeration.
I let you. Table 5 shows the average water quality after the treatment. (5) Aggregation / precipitation step To remove phosphorus components in the oxidized wastewater,
Add a flocculant to water to flocculate and precipitate phosphorus components.
Was. Two reactors with a stirrer with a capacity of 10 liters
Before adjusting the pH to 6.5-7.0 in the first reactor.
The wastewater after the process is supplied at 1920 liters / day,
20m as aluminum with poly aluminum chloride (PAC)
Add and mix an aqueous solution containing g / l at 0.6 liter / day
(Residence time 15 minutes) and send to the next reaction tank, polymer aggregation
KEA-347 (manufactured by Environmental Engineering Co., Ltd .:
Aqueous solution of modified polyacrylamide (concentration 0.1 wt.
%) At 5.7 l / day and mixed (residence time 1
5 minutes). This liquid is cross-shaped or grid-shaped paddle wing
And generate convection up and down at the bottom of the paddle wing
Housed in a hollow drive shaft that rotates the turbine blades for
To a high-speed coagulating sedimentation device,
To precipitate. Displays the average water quality of the wastewater from which sediment has been removed.
It is shown in FIG. [0057] [Table 5] From the results shown in Table 5, processing was performed through each step of the present invention.
BOD, TN and TP are very low level
It can be seen that it has been reduced to [0059] According to the present invention described above, BO in waste water
D, TN and TP can be efficiently reduced or removed.
You. Furthermore, the equipment used in each process can be made more compact.
And when conventional methods or devices are combined
Plant construction is possible with a significantly smaller installation area
is there.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a flow of all steps of the present invention. . FIG. 2 is a schematic view showing one example of an apparatus used in a step (2). FIG. 3 is a schematic view of an apparatus used in step (2) of an example. [Description of Signs] 1: Denitrification tank 2: Raw water inflow pipe 3: Raw water receiving section 4: Stirrer shaft and raw water falling pipe 5: Turbine blade 6: Paddle blade for sludge stirring 7: Variable stirrer 8: Treated water collecting section 9: treated water outlet 10: sampling tube 11: sludge waste sludge outlet 12: drain outlet 13: pedestal M: motor P _1: pump P _2: pump

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shinya Kurata 1-9-8 Higashikanda, Chiyoda-ku, Tokyo Environmental Engineering Co., Ltd. (72) Inventor Noriyuki Komiya 1-9-8 Higashikanda, Chiyoda-ku, Tokyo Environmental Engineering (72) Inventor Keiji Hon 1-9-8 Higashi Kanda, Chiyoda-ku, Tokyo Environmental Engineering Co., Ltd. (72) Inventor Kazuhide Honda 5-1-39 Ryoke, Kawaguchi-shi, Saitama Nippon Chemi-Tech Corporation (56) References JP-A-8-80488 (JP, A) JP-A-60-212296 (JP, A) JP-A-57-63197 (JP, A) JP-A-63-214398 (JP, A) JP-A-56-38175 (JP, A) JP-A-60-31896 (JP, A) JP-A-60-212295 (JP, A) JP-B-63-39308 (JP, B1) (58) (Int. Cl ^7, DB name) C02F 1/00 -. 9/00

Claims (1)

(57) [Claims 1] A step (1) of stripping waste water containing a high BOD component, a nitrogen component, a phosphorus component, etc., at least with ammonia nitrogen, and removing nitrate nitrogen biologically. (2), BOD and / or organic nitrogen activated sludge treatment (3), ammonia nitrogen chemical oxidation treatment (4), and phosphorus component coagulation precipitation (5)
In the above-described order .