JP2003181490A - Water treatment facilities and sludge treatment facilities - Google Patents

Abstract

(57) [Abstract] (Modified) [Problem] To provide a water treatment facility and a sludge treatment facility that exhibit a particularly remarkable effect when performing effective utilization such as composting of dewatered sludge, and in terms of water content. And a water treatment facility and a sludge treatment facility capable of having a detection and adjustment function so that uniform characteristics can be maintained. An aeration tank provided with aeration means and a sedimentation separation tank.
In a biological water treatment facility having a sludge return step of returning at least a part of the sludge solid-liquid separated in the sedimentation separation tank 5 to the previous step, in the sludge return step before the aeration tank 4, It has a chemical administration means 30 for promoting the activated sludge treatment, and is provided with a dehydrator 6 for pulling out the settled sludge from the sedimentation separation tank 5 and directly dehydrating without adding a chemical.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water treatment facility and a sludge treatment facility.
The present invention relates to a water treatment facility and a sludge treatment facility that exhibit particularly remarkable effects when composting dehydrated sludge.

[0002]

2. Description of the Related Art A biological water treatment system including sludge treatment adjusts a process such as a primary sedimentation basin that separates and removes contaminants such as sand and dust in advance and the flow rate of wastewater (for adjusting the concentration of organic matter). Adjustment tank, aeration tank equipped with aeration means for biological treatment, settling separation tank consisting of final settling basin, step of returning at least part of the sludge that has settled and separated to the previous step, etc. When the sludge drawn out from the final settling tank is dehydrated, a polymer flocculant, etc. is administered and the water content is about 85% to 60% in some cases by various dehydrators according to the purpose. It is dehydrated to some extent.

As the coagulant used for dehydration, iron or calcium-based inorganic compounds have been the mainstream before, but nowadays, polymer-based coagulants are often used.

Excess sludge generated by the treatment of organic wastewater and sewage (excess sludge for maintaining a constant sludge concentration in the treatment system in which organic matter in wastewater is converted to sludge by the growth of microorganisms) is used in water purification treatment. Since many organic components have a greater affinity for water than in the case, it has been conventionally inevitable to add a coagulant. However, depending on the type of coagulant, the coagulant component itself becomes an obstacle when composting dehydrated sludge, and the cost of the coagulant is not a small percentage of the maintenance cost of the treatment facility.

[0005]

DISCLOSURE OF THE INVENTION As a result of earnest research aimed at establishing a dehydration system that does not use a coagulant, the present inventors have found that a drug administration means is provided in a preceding step of an aeration tank (aeration tank) including a sludge returning step. The present invention has been completed by providing a chemical mixing sludge circulating means in the aeration tank to improve sludge, and to complete the technology of chemical-free dehydration.

Further, the present inventors have found that the dewatering property of sludge can be provided with a detection and regulation function so that uniform properties such as water content can be maintained.
The present invention has been achieved.

[0007] Therefore, it is an object of the present invention to provide a water treatment facility and a sludge treatment facility which have an outstanding economic effect and exhibit a particularly remarkable effect when the dehydrated sludge is effectively used for composting or the like. To do.

Another object of the present invention is to provide a water treatment facility and a sludge treatment facility which can be provided with detection and adjustment functions so that uniform characteristics such as water content can be maintained. .

[0009]

The above-mentioned problems can be solved by the following inventions.

(Claim 1) A biology having an aeration tank equipped with aeration means and a sedimentation separation tank, and having a sludge returning step of returning at least a part of the sludge solid-liquid separated in the sedimentation separation tank to a previous step. In a conventional water treatment facility, in a pre-process including the sludge returning process before the aeration tank, a chemical administration means for accelerating the activated sludge treatment is provided, and the sedimentation sludge in the sedimentation separation tank is drawn out without adding the chemical. A water treatment facility having a dehydrator for direct dehydration.

(Claim 2) A biology having an aeration tank equipped with aeration means and a sedimentation separation tank, and having a sludge returning step for returning at least a part of the sludge solid-liquid separated in the sedimentation separation tank to a previous step. In a conventional water treatment facility, a chemical administration means for accelerating the activated sludge treatment is provided in a previous step including the sludge returning step before the aeration tank, and one of the treated water and / or the treated sludge is discharged from the aeration tank. A dehydrator that draws out a portion of the sludge and draws out the settled sludge from the settling separation tank, and directly dehydrates it without adding a chemical A water treatment facility characterized by having ingredients.

(Claim 3) Sludge settling which is a control tank, an aeration tank, and a sedimentation separation tank to which a chemical for accelerating the activated sludge treatment is administered from a chemical administration means provided in a previous step including a sludge returning step before the aeration tank. The pond and dehydrator are arranged in series,
The water treatment facility according to claim 1 or 2, wherein there is no means for adding a chemical between each tank and the equipment.

(Claim 4) An agent for promoting the treatment of activated sludge, which is administered by a drug administration means provided in a previous step including a sludge returning step before the aeration tank, is a nitrogen-containing agent containing oxycarboxylic acids, carbohydrates and amino acids. The water treatment facility according to claim 1, 2 or 3, which is an organic compound, an alkaline earth metal salt and / or a silicic acid compound.

(Claim 5) A nitrogen-containing organic compound containing oxycarboxylic acids, carbohydrates, amino acids together with a compound having a polyvalent hydroxyl group in the object circulation mixing means.
At least one selected from an alkaline earth metal salt or a silicic acid compound is used in combination.
The water treatment facility according to any one of 1.

(Claim 6) In the water treatment facility according to any one of claims 1 to 5, dewaterability, drying property and water content of the sludge drawn from the settling separation tank and / or the dehydrated sludge dewatered by a dehydrator. Based on the measurement result of at least one characteristic of the rate, each effect of the aeration means, the drug administration means and / or the withdrawal of the sludge, and if necessary, the mixing in the object circulation mixing means and the returning means is controlled. Water treatment facility.

(Claim 7) In the water treatment facility according to any one of claims 1 to 5, based on the measurement result of the amount of dissolved oxygen in the aeration tank, aeration means, drug administration means and / or withdrawal of the sludge. A water treatment facility characterized by controlling the respective effects of the mixing and returning means in the means for circulating and mixing the treated materials as necessary.

(Aspect 8) An aeration tank comprising an aeration tank equipped with aeration means and a sedimentation separation tank, and including a sludge returning step of returning at least a part of the sludge solid-liquid separated in the sedimentation separation tank to a previous step. Having a chemical administration means for promoting the treatment of activated sludge in the previous step before the tank, extracting a part of the water to be treated and / or the sludge to be treated from the aeration tank, mixing it with a compound having a polyvalent hydroxyl group, and then aeration the same. In a sludge treatment facility that treats sludge generated from a biological water treatment facility that has means for circulating and mixing the substances to be treated to be returned to the tank, a dehydrator that directly dehydrates the sludge generated from the water treatment facility without adding a chemical agent A sludge treatment facility comprising:

(Claim 9) An agent for promoting the treatment of activated sludge, which is administered by a drug administration means provided in a previous step including a sludge returning step before the aeration tank, is a nitrogen-containing agent containing oxycarboxylic acids, carbohydrates and amino acids. The sludge treatment facility according to claim 8, which is an organic compound, an alkaline earth metal salt, and / or a silicic acid compound.

(Claim 10) In the means for circulating and mixing an object to be treated, a compound having a polyvalent hydroxyl group is selected from nitrogen-containing organic compounds containing oxycarboxylic acids, carbohydrates and amino acids, alkaline earth metal salts or silicic acid compounds. At least one of the above is used in combination.
Or the sludge treatment facility according to 9.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

FIG. 1 is a diagram showing an embodiment of the present invention. In FIG. 1, reference numeral 1 is a screen for removing contaminants in the inflowing waste water, and examples thereof include a coarse screen and a fine screen. Can be used alone or in combination. The screen may be a fixed type, but it is also preferable to use a rotary type such as a drum screen. Reference numeral 2 is a first settling basin, which sediments and separates the sand and the like that have passed through the screen 1. Reference numeral 3 is an adjusting tank, which is a tank that plays a role of adjusting the amount of wastewater and the concentration of wastewater when they change daily. Reference numeral 4 is an aeration tank, in which activated sludge inhabits, and is equipped with an aeration means (not shown). Reference numeral 5 denotes a final settling tank which is a settling separation tank, and separates a mixed solution or suspension of sludge and wastewater sent from the aeration tank 4 into treated water and sludge.

In the present invention, the drug administration means 3 is provided in the adjusting tank 3 and the like located in the preceding step including the returning sludge step rather than the aeration tank 4.
Drugs are administered from 0. The drug administration means 30 mainly includes a drug administration tank and a drug administration pump (not shown), a powder feeder, or the like.

The drug to be administered is a drug that promotes treatment of activated sludge, and such a drug has a function of sprouting heterotrophic bacteria (bacillus genus bacteria), for example, and promoting vegetative cell formation.

Preferred examples of such agents include oxycarboxylic acids, carbohydrates, nitrogen-containing organic compounds containing amino acids, alkaline earth metal salts and / or silicic acid compounds. Examples of carbohydrates include carbohydrates such as monosaccharides, disaccharides, and some polysaccharides that are easily decomposed by microorganisms.

A suspension obtained by hydrolyzing a substance containing a protein can also be a good drug for administration.

Further, the alkaline earth metal salt may be either a calcium salt or a magnesium salt, but the magnesium salt is preferred from the viewpoint of activating the above-mentioned Bacillus bacterium.

The silicic acid compound is preferably one which is relatively water-soluble at the time of introduction, such as so-called activated silica.

The drug is preferably administered so that the concentration of each component as an anhydride is 0.1 to 10 mg / l.

In the present invention, when administering a drug, an organic compound such as a nitrogen-containing organic compound containing an oxycarboxylic acid, a carbohydrate or an amino acid, and an inorganic compound such as an alkaline earth metal salt and / or a silicic acid compound are used. Although it is preferable to use both of them at the same time for administration, the effect can be exhibited even if only one of them is administered.

It is also preferable to use an alkaline earth metal salt and a silicic acid compound in combination, but either one may be used.

In addition to the sludge return line and the adjusting tank 3, the drug administration from the drug administration means 30 can be added to the primary sedimentation tank 2 or the like. However, in consideration of dispersibility and diffusibility of the drug, it is preferable to administer the drug to the sludge returning line, the adjusting tank 3, and the like.

In the aeration tank 4, a part of the water to be treated and / or the sludge to be treated is extracted from the aeration tank 4, mixed with a compound having a polyvalent hydroxyl group, and then returned to the aeration tank 4. Means 40 are provided.

The material circulation mixing means 40 is a line for extracting a part of the water to be treated and / or the sludge to be treated (may include a power source for withdrawal), a mixing tank for the chemicals, and an aeration tank for the mixed liquid after mixing. It consists of a return line (which may include a return power source).

The residence time in the mixing tank may be 1 second or longer, but is preferably 5 seconds or longer. When a compound having a polyvalent hydroxyl group is mixed in the object circulation mixing means 40, it is preferable that the compound is filled (loaded) in a mixing tank for the sake of convenience of processing. The load is preferably 10% or more of the capacity of the mixing tank in order to maintain good physical contact efficiency. Extraction amount to the mixing tank is 0.1 to 0.1% of the total processing amount.
It is in the range of 30% and varies depending on the scale of processing and the processing target.

Examples of the compound having a polyhydric hydroxyl group used in the object circulation mixing means 40 include a phenol compound multimer, a quinone compound simple substance or a multimer, and so-called polyphenols and humic substances. , Humic compounds (including humic acids and fulvic acids), etc. are also included.

The quantitative ratio at which the compound having a polyvalent hydroxyl group comes into contact with the circulating sludge is preferably 0.1 to 100 mg / l (relative to the circulating sludge).

In the present invention, the compound having a polyvalent hydroxyl group can be used in combination with the object circulation mixing means 40 and the above-mentioned chemical agent for promoting the treatment of activated sludge. As such a drug, the same drug as that used for the drug administration means 30 can be used.

Since human waste water already contains a certain amount of nutrients, it is possible to omit the addition of the above-mentioned organic agents such as amino acids, polysaccharides, oxycarboxylic acids and protein-containing substances.

When a compound having a polyvalent hydroxyl group is mixed in the aeration tank 4 by using the object circulation mixing means 40, the activity of so-called spoilage bacteria is lowered, and sludge is decomposed in the subsequent steps. Sludge is reformed such that the progress becomes difficult and the effect of decomposing organic components correspondingly increases. Specifically, Bacillus bacteria can be activated as a result.

The modified activated sludge is separated into sludge and treated water in the final settling basin 5, most of the settled sludge is returned to the aeration tank 4, and part of it is withdrawn as excess sludge, which is necessary. Is concentrated in the concentrating tank and directly dehydrated by the dehydrator 6 without adding a chemical.

The present invention is characterized in that the so-called chemical-free dehydration as described above is realized. What enables such chemical-free dehydration is to promote the activated sludge treatment in the above-mentioned water treatment facility. By providing a drug (germination-promoting drug) administration means 30 and a treatment object circulation mixing means 40 in which a compound having a polyvalent hydroxyl group is mixed, activation and modification of sludge are achieved, and hydrophilicity in sludge is improved. It is highly probable that this was due to a decrease in the amount of substances and ultimately to the mineralization of sludge.

The water treatment facility of the present invention comprises a regulating tank, an aeration tank,
In a mode in which the sludge settling basin and the dehydrator are arranged in series, there is no means for adding a chemical agent relating to the operation of the dehydrator. Here, “arranged continuously” means that the treatment sequences are continuous, and does not mean that the installation positions are arranged continuously in parallel.

Next, the sludge treatment facility of the present invention has an aeration tank 4 equipped with aeration means and a settling separation tank 5, and activated sludge treatment is performed during the process including the sludge returning process before the aeration tank 4. It has a medicine administration means 30 for promoting, a part of the water to be treated and / or the sludge to be treated is extracted from the aeration tank 4, and the aeration is performed after mixing with the agent for promoting the treatment of activated sludge and / or the medicine having antibacterial properties. In a sludge treatment facility that treats sludge generated from a biological water treatment facility that has a treatment object circulation mixing means 40 that is returned to the tank 4, the sludge generated from the water treatment facility is directly dehydrated without adding a chemical agent. It is characterized by having a dehydrator.

As the dehydrator 6 used in the present invention, a filter press type dehydrator can be preferably used, but another dehydrator can also be used.

The same chemicals or compounds having a polyvalent hydroxyl group as those used in such a sludge treatment facility can be used.

Next, suitable control means for satisfactorily operating the water treatment facility and the sludge treatment facility of the present invention will be described.

The first control means is based on the measurement result of at least one characteristic of dewatering property, drying property and water content of the sludge drawn out from the settling separation tank 5 and / or the dehydrated sludge dewatered by the dehydrator 6. Aeration means, drug administration means 30
And / or a mode of controlling the withdrawal of the sludge and, if necessary, the mixing and returning in the object circulation mixing means 40.

Here, the measurement of characteristics includes measurement and monitoring. Further, the control of the aeration means includes the adjustment of the aeration amount, the control of the drug administration means 30 includes the adjustment of the drug dose, the control of the sludge withdrawal includes the adjustment of the withdrawal amount, and the object circulation circulation mixing is performed. The control of the mixing in the means 40 includes the adjustment of the mixing amount and the circulation amount of the compound having a polyvalent hydroxyl group, and the control of the returning includes the adjustment of the returning amount and the returning concentration.

That is, for example, in order to operate the facility satisfactorily, at least one measurement and monitoring are conducted from the items of sludge dewatering property, drying property, and water content, and the results are used to determine the water treatment facility or sludge treatment of the present invention. It controls facilities.

The measurement and monitoring of the dehydration property can be carried out not only by the normal Nutsche test, the capillary suction test, the thermal analysis method but also by the direct measurement such as the measurement of the torque of the drive part of the dehydrator 6. it can. Since the thermal analysis method can grasp the hydrophilic component / hydrophobic component amount ratio and the like from the difference in water evaporation due to temperature rise, it is suitable as a monitoring means for this process control.

As described above, the water content can be obtained from the characteristic value (axial torque, etc.) of the dehydrator 6 by its correlation, or a moisture meter can be attached.

From the results of these measurements and monitoring, when it is judged that the dehydration property of the drawn-out sludge is insufficient (the hydrophilicity is too large), the drug administration amount and the withdrawal / mixing / returning amount are adjusted. A method of adjusting the aeration amount while keeping the above amount constant is also preferably performed.

Next, the second control means can perform the same control as the above-mentioned first control means based on the measurement result of the dissolved oxygen amount in the aeration tank 4.

[0054]

EFFECTS OF THE INVENTION According to the present invention, in addition to achieving deodorization and reducing the amount of surplus sludge generated, it is possible to significantly improve the dehydration property and maintain its characteristics stably, and the concentrated sludge of sewage can be removed by the dehydrator. Allows medicated dehydration. The deodorization without using a coagulant has a great economic effect, and when composting dehydrated sludge, it is significant not to mix a coagulant that may inhibit fermentation.

[0055]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 The following experiment was conducted in a water treatment process using a standard activated sludge method tester with a rated capacity of about 8 to 9 m ³ / day. In this process, the sludge returning section was provided with a drug administration means, and the aeration tank was provided with a circulation mixing means for the object to be treated having a mixing tank.

A part of the concentrated sludge as a protein-containing substance is partly decomposed by the drug administration means provided in the adjusting tank.
Added at a rate of 10 mg / l dry weight.

In addition, a humic substance was used as the polyvalent hydroxyl group-containing substance in the means for circulating and mixing the substance to be treated. About 50% of this was filled in the mixing tank, and the withdrawal amount (circulation amount) to the mixing tank was about 5% of the total treated amount.

The concentrated sludge drawn out from the lower part of the sludge concentration tank of the present water treatment process was subjected to chemical-free dehydration by means of a belt press type dehydrator (10 chambers, filtration area 2 m ² ) attached.

The water content of dewatered sludge in a steady state (stable) is 60.
It was slightly smaller than%.

The water content of the dehydrated sludge was measured by an infrared absorption water content meter. The variation in water content increased uniformly over 2-3 days, and when it exceeded 60%, it was tried to recover the water content by the following means.

(1) Adjustment of aeration amount: Aeration amount is 10 to 50
Increased in the range of%. (2) Adjustment of drug dose: The dose was increased at a rate of 10 mg / l to 1 mg / l. (3) Controlling the circulating amount to the extracting, mixing and returning means: The circulating amount was increased at a rate of 5% to 1%.

It has been confirmed that even if only one of the above three means is used, it is possible to induce a water content of 60% or less again by increasing the increase amount.

It was also confirmed that the combined use of a plurality of means makes it possible to reduce the amount of increase of each means in any combination as compared with the case of using a single means.

However, it was impossible to reduce the water content of the sludge to 60% or less only by adjusting the aeration amount without performing drug administration or circulation mixing. At this time, it was necessary to administer a polymer flocculant to the sludge before dehydration.

Example 2 In the experiment of Example 1, a dissolved oxygen meter was attached to the aeration tank, and the aeration amount, drug dose and circulation amount were controlled from the measured values.

At this time, the amount of aeration is adjusted by adjusting the dissolved oxygen concentration in the aeration tank within a predetermined range (in the case of this process, 1.2 to 3.
0 mg / l) was prioritized. Otherwise, the same examination as in Example 1 was carried out.

In this example, the dissolved oxygen concentration in the aeration tank could be set to the optimum value (about 1.5 mg / l), so that COD and the like could be treated more efficiently. The treated water had a 25% reduction in COD.

Example 3 In the test for controlling (1), (2), and (3) of Example 1, the drugs to be administered and the substances to be mixed in the process were conducted in the following combinations.

Under the initial conditions of Example 1, the water contents of the compared dehydrated sludges were as follows. The water content value obtained by adding the polymer coagulant when the main administration and mixing are not performed. When the coagulant is not added, the dehydrated sludge (sludge having a water content of 85% or less) is put into a dehydrator. It was difficult to get.

The sludge having a water content of 65% or less was in a highly dehydrated state, and when composting, the fermentation proceeded satisfactorily only by adding auxiliary materials. Dewatered sludge having a water content of more than 65% and up to 70% required some drying treatment in a compost yard. If it exceeds 70%, the temperature cannot be raised to a sufficiently high temperature (70 ° C) during fermentation unless it is first dried by a dryer.

[0072]   (Measurement result of water content)       Drug to be administered Mixture Water content (wt%)   Hydrolyzed protein suspension Humus substance 61   Oxidatively decomposed protein suspension humus substance 59   1-alanine + magnesium sulfate humic acid 60   d, l-Glucose + activated silicic acid Humic acid 63   Tartaric acid + MgSO4 + SiO2 anthraquinone 63   1-Alanine + magnesium sulfate None 66     None Humus substance 68     None None 75

Example 4 In the treatment of human waste, dehydration without chemicals (without using a flocculant) was attempted by means of mixing a polyvalent hydroxyl group-containing substance without administering a drug. The circulating amount was 0.3% and 1% of the total amount treated.

As a result of adjusting conditions including the outside air temperature other than the circulation amount and comparing the water contents after dehydration, the former was 63% and the latter was 55%.

In the case of human waste, it was considered that the nutrients to be activated were already present, and the drug was not necessarily required.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

[Explanation of symbols]

1: Screen 2: First sinking pond 3: Adjustment tank 4: Aeration tank 5: Sedimentation separation tank 6: Dehydrator 30: Medication administration means 40: means for circulating the object to be treated

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Mamoru Mizuguchi             2-3-20-Konancho, Higashinada-ku, Kobe-shi, Hyogo             412 (72) Inventor Osamu Hamamoto             5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui             Inside the ship company (72) Inventor Masahiro Saito             5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui             Inside the ship company F-term (reference) 4D028 AA02 AC06 AC09 BC01 CA00                       CA09 CA11 CA15 CC00 CC07                 4D059 AA03 BE10 BE15 BE51 CA22                       CA28 CC01 EA01 EA20

Claims (10)

[Claims] 1. A biological water treatment system comprising an aeration tank equipped with aeration means and a sedimentation separation tank, and having a sludge returning step for returning at least a part of the sludge solid-liquid separated in the sedimentation separation tank to a previous step. In the facility, in the pre-process including the sludge return process before the aeration tank, there is a drug administration means for accelerating the activated sludge process, and the settled sludge in the settling separation tank is drawn out and directly dehydrated without adding the drug. A water treatment facility having a dehydrator. 2. A biological water treatment having an aeration tank equipped with aeration means and a sedimentation separation tank, and having a sludge returning step of returning at least a part of the sludge solid-liquid separated in the sedimentation separation tank to a previous step. In the facility, in the pre-process including the sludge returning process before the aeration tank, a chemical administration means for accelerating the activated sludge treatment is provided, and the treated water and / or a part of the treated sludge is extracted from the aeration tank. , Having a dehydrator for mixing with a compound having a polyhydric hydroxyl group and returning the mixture to the aeration tank to circulate the object to be treated, extracting the settled sludge from the settling separation tank, and directly dehydrating it without adding chemicals Water treatment facility characterized by. 3. An adjusting tank, an aeration tank, a sludge settling tank which is a settling separation tank, to which a chemical for accelerating the activated sludge treatment is administered from a chemical administration means provided in a previous step including a sludge returning step before the aeration tank. The water treatment facility according to claim 1 or 2, wherein dehydrators are arranged in series and have no means for adding a chemical between each tank and the equipment. 4. A chemical for promoting activated sludge treatment, which is administered by a chemical administration means included in a previous step including a sludge returning step before the aeration tank, is a nitrogen-containing organic compound containing oxycarboxylic acids, carbohydrates and amino acids, The water treatment facility according to claim 1, 2 or 3, wherein the water treatment facility is an alkaline earth metal salt and / or a silicic acid compound. 5. In the means for circulating and mixing an object to be treated, at least one selected from oxycarboxylic acids, carbohydrates, nitrogen-containing organic compounds containing amino acids, alkaline earth metal salts or silicic acid compounds together with a compound having a polyvalent hydroxyl group. The water treatment facility according to any one of claims 2 to 4, wherein a seed is used in combination. 6. The water treatment facility according to any one of claims 1 to 5, wherein at least dewatering property, drying property and water content of the sludge drawn out from the settling separation tank and / or the dehydrated sludge dewatered by a dehydrator. A water treatment facility characterized by controlling each effect of an aeration means, a drug administration means and / or withdrawal of said sludge, and if necessary, a mixing and circulation means for circulating the object to be treated, based on the measurement result of one characteristic. . 7. The water treatment facility according to any one of claims 1 to 5, based on the measurement result of the amount of dissolved oxygen in the aeration tank,
Aeration means, drug administration means and / or withdrawal of the sludge, and if necessary, mixing in the object circulation mixing means,
A water treatment facility characterized by controlling each effect of return means. 8. An aeration tank prior to the aeration tank, comprising an aeration tank equipped with aeration means and a sedimentation separation tank, and including a sludge returning step of returning at least a part of the sludge solid-liquid separated in the sedimentation separation tank to a previous step. Having a drug administration means for accelerating the treatment of activated sludge in the previous step, extracting a part of the water to be treated and / or the sludge to be treated from the aeration tank, mixing it with a compound having a polyvalent hydroxyl group, and returning it to the aeration tank. In a sludge treatment facility for treating sludge generated from a biological water treatment facility having means for circulating and mixing substances to be treated, there is provided a dehydrator for directly dehydrating the sludge generated from the water treatment facility without adding a chemical agent. A sludge treatment facility characterized by this. 9. A nitrogen-containing organic compound containing an oxycarboxylic acid, a carbohydrate or an amino acid, wherein the agent for promoting the treatment of activated sludge, which is administered by a drug administration means included in a previous step including a sludge returning step before the aeration tank, The sludge treatment facility according to claim 8, which is an alkaline earth metal salt and / or a silicic acid compound. 10. In the means for circulating and mixing an object to be treated, at least one selected from oxycarboxylic acids, carbohydrates, nitrogen-containing organic compounds containing amino acids, alkaline earth metal salts or silicic acid compounds together with a compound having a polyvalent hydroxyl group.
The sludge treatment facility according to claim 8 or 9, wherein seeds are used in combination.