JPH0321400A - Sewage/sludge treatment method and system - Google Patents

Abstract

PURPOSE:To make dewatering easy and prevent becoming sludge again by adding a polymer flocculant in a specified amount to a raw sludge, dewatering flocculated granules, adding a powdered agent containing quicklime and water- insoluble granules to the resultant sludge, and kneading the mixture. CONSTITUTION:A polymer flocculant is added in 0.3-1.5wt.% of the solid substance content to raw sludge or concentrated sludge, and after sludge granules are flocculated by uniform mixing, they are dewatered by a solid-liquid separation screen. A powdered agent containing quicklime and water-insoluble granules is added to the obtained dewatered flocculated sludge, the mixture is kneaded, and flocculated granules are fined and water is separated. Further, the powdered agent containing quicklime and water-insoluble granules is mixed and stirred uniformly with a suspension containing the resultant fiend particles and thus solid coatings of calcium hydroxide and the water-insoluble particles are formed on the surfaces of the fined particles and the hydrophobic fine particles are flocculated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates generally to sewage treatment methods and sewage or sludge treatment systems, and more particularly to sewage treatment and systems as domestic wastewater. However, the present invention can also be applied to the treatment of industrial wastewater or mixed wastewater of industrial wastewater and domestic wastewater.

Prior Art Sewage/sludge treatment systems, such as the one shown in FIG. 3, are known in the art.

In this known method, wastewater is stored in a storage tank 1 and precipitated (in the figure, the wastewater is concentrated and precipitated in two stages: a storage tank 1-1 and a wastewater tank 1-2). The clear liquid is stored in multiple water treatment tanks 2 (in the figure, flow rate adjustment tank 2-1, aeration tank 2
-2. Sedimentation tank 2-3. Pass through the disinfection tank 2-4) to the designated BO
D value. After purifying the sludge to a predetermined COD value, it is discharged into a river or the like, while the settled sludge is led into a sludge polymer mixing tank (corresponding to a stirring tank) 3.

The sludge introduced into the sludge/polymer mixing tank (stirring tank) 3 is mixed with the polymer flocculant introduced from the polymer flocculant supply means to produce flocculated particles. In the illustrated conventional method, the polymer flocculant supply means introduces the polymer flocculant from the polymer flocculant storage tank 4 to the mixing tank 5, dissolves it in dilution water, and then
It is shown as supplying a polymer flocculant solution to the flocculating tank 3.

The particles in the sludge are aggregated into large particles by a polymer flocculant, dewatered by a squeezing means 6 such as a belt press, and then transported 7 to an appropriate location. The effluent produced in the squeezing means 6 is returned to the water treatment tank 2 or the storage tank l.

Typical data for the method and system described above are entered in each part of the drawing, with percentages indicated in large numbers.
is the percentage of the total weight of the material to be treated or treated waste in each part of the contents in each part to the total weight of wastewater led to the reservoir; The moisture content of each treated product is shown.

Problems to be Solved by the Invention In the above-mentioned sewage treatment method and system, solid content in sewage is precipitated into sludge, a polymer flocculant is added to the sludge, a polymer flocculant is added to the sludge, and a polymer flocculant is added to form relatively large flocculated particles, which are then compressed. Since it only involves dehydration, it has the following disadvantages.

(1) Although the total weight of waste after treatment based on the total amount of treated wastewater typically decreases to about 0.0666%, particles flocculated by polymer flocculants have a relatively large water-holding capacity, and after dewatering, Even if attempts were made to further dehydrate and dry the waste through natural curing, no significant effect could be expected as the internal drying did not proceed after the surface had dried.

For example, the total amount of domestic wastewater discharged per person is approximately 2 liters per day.
000 (approx. 200 kg),
The total amount of sewage discharged in a small and medium-sized city with a population of 50,000 is 10,000.
000. o0012 (approximately 10.ooo.ooOkg). Therefore, the amount of waste after treatment in the above-mentioned equipment is 6.66012 (approximately 6,660 kg) per day.
The volume or weight of the waste will not decrease below that amount.

(2) Waste after treatment contains bacteria. Because of its foul odor, the waste must be incinerated or disposed of in an appropriate location (eg, dumped at sea). The costs of equipment, transportation costs, personnel costs, etc. required for these are enormous.

(3) Furthermore, compressing means such as a belt press have high equipment costs, require manpower for maintenance, and have high running costs.

(4) When waste is left in a pile, once the surface dries, the moisture inside is difficult to evaporate, and the dry part of the waste is easily re-sludged by rainwater. Therefore,
Disposal location. There are restrictions on how it can be disposed of, making it unsuitable for use as fertilizer or soil improvement material.

(5) The liquid squeezed out by the belt press must be combined with the supernatant liquid from the storage tank and concentration tank, and discharged into the river via an aeration tank, sedimentation tank, and disinfection tank.

Means for Solving the Problems In the method and system of the present invention, sludge led from a settling tank is mixed with a polymer flocculant to flocculate it, then lightly dehydrated in a rotating screen drum, and flocculated by a kneading means. The resulting particles are finely divided, uniformly mixed with a powder containing quicklime and water-insoluble particles (preferably calcium carbonate), piled up, cured, and dried.

Specifically, in the present invention, solid content in sewage is precipitated to form sludge, and a polymer flocculant is added to this to form a mixed phase of relatively large flocculated particles and water. After drying and lightly dewatering using a rotating screen drum, the agglomerated particles are finely divided to separate filth particles and water, and further contain at least quicklime, preferably quicklime and water-insoluble particles (preferably calcium carbonate)
By adding a powder containing at least the following to separate water from the filth particles and chemical fractions in the sewage, and to coat the filth particles and form a solid film insoluble in water,
It is easy to release moisture and is re-sludged and treated in a separated state.

For production The effects of the present invention are as follows.

(1) Since a rotating screen drum and kneading means, which have a simpler structure than a squeezing means such as a belt press, are used, the equipment cost and maintenance cost are reduced to about 1/5 of the conventional method.

(2) Since the quicklime contained in the powder agent makes the sludge highly alkaline, many bacteria are sterilized, which is advantageous in terms of hygiene and odor control.

(3) The quicklime in the powder reacts with the water in the sludge to generate heat and accelerate the evaporation of water.

(4) The quicklime in the powder dissolves in the water in the sludge to generate calcium ions, which combine with various malodorous substances to stabilize them and provide a deodorizing effect. At this time, water is often recycled, and the recycled water flows out and evaporates, significantly reducing the volume of waste after treatment.

(5) The quicklime in the powder neutralizes acidic sewage/sludge.

(6) The quicklime in the powder forms a calcium hydroxide (slaked lime) film on the surface of the finely divided sludge particles, and also attaches water-insoluble particles, and the formed calcium hydroxide film is exposed to the outside air. It reacts with the carbon dioxide gas inside to form a solid film of calcium carbonate. At this time, the water-insoluble flow particles are interposed between the dirt particles and help form a calcium hydroxide film.

(7) Thus, the treated waste is almost sterilized and has almost no odor, so it can be piled up and dried.

(8) In this way, sludge particles covered with a calcium carbonate film (hereinafter referred to as coated particles) allow moisture to flow out and evaporate through the gaps between them, and when left in a pile, their volume and weight rapidly increase. can be reduced.

Moreover, the coated particles are not re-sludged by irrigation such as rainwater.

For example, typical settled sludge with a moisture content of about 98.5% has a moisture content of about 80-82% immediately after treatment, but if left in a pile, it will have a moisture content of about 20-40.1% after a week. Indicates moisture content. Therefore, its volume and weight are reduced to 1/2 to 1/5 of the volume of sludge received in the coagulation tank. Therefore,
The cost of transporting treated waste to other locations is significantly reduced.

(9) Moreover, the waste after treatment can be used as fertilizer, soil conditioner, etc.
It can be used as a ground improvement material for soft ground. Furthermore, when waste is incinerated, the cost of incineration is significantly reduced because the water content is low.

(10) The liquid filtered in the rotating screen drum is not forcibly dehydrated by compression, so its BOD and COD values are each 200 pp+
In some cases, the amount is less than m or less than 30 pp+s, and there is a possibility that it can be discharged directly into rivers. Therefore, the amount of liquid to be purified in the purification layer 2 is reduced.

Embodiment FIGS. 1A and 1B are flowcharts for comparing and explaining the conventional method and the method of the present invention, respectively, and FIG. 2 is a layout diagram of the system of the present invention.

As can be seen from FIGS. 1a and 1b, the feature of the method of the present invention lies in the area surrounded by dotted lines. The rest is substantially the same as the conventional method.

In Fig. 2, 10 is a storage tank, a water storage tank 11 and a concentration tank 1.
It is shown as consisting of 2.

Sewage may be supplied to the water storage tank 11 by a vacuum car or the like as shown in the figure, or directly from a sewage pipe.
Alternatively, it may be guided through a flow rate regulating tank (not shown). The sludge precipitated in the water storage tank 11 is discharged to the thickening tank 12 by the pump P, and the thickened sludge precipitated in the thickening tank 12 is guided to the flocculating tank 20 by the pump P.
The supernatant liquid is led to a septic tank 30.

The septic tank 30 has a flow rate adjustment tank 31. Aeration tank 32. Sedandan 3
3, shown as consisting of a disinfection tank 34, with the movement of liquid between them shown as being by overflow.

The sludge from the second thickening tank l2 and the sediment 133 in the septic tank 30 is guided to the flocculation tank 20 by the pump P.

The flocculation tank 20 is provided with stirring means 2l, such as a stirring blade, for example. The polymer flocculant led from the polymer flocculant storage tank 22 and the water led from a suitable water supply source 23 are made into a uniform solution by the stirring means 25 in the polymer dissolving tank 24, and then dissolved in the flocculating tank 20. The sludge particles are coagulated by a polymer flocculant to form large coagulated particles.

At this time, a portion of the water in the sludge is taken into the coagulated particles, but a portion is discharged outside the coagulated particles, resulting in a mixture of the coagulated particles and sewage as a whole.

The polymer flocculants used may be the same as those used in conventional methods; for example, anionic ones include sodium alginate, sodium polyacrylate, salts of maleic acid copolymers, and salts of partially hydrolyzed polyacrylamide. Cationic ones include water-soluble aniline resin hydrochloride, borithiourea hydrochloride, polyethyleneaminotriazole, polyvinylpenzyltrimethylammonium chloride, polyethyleneamine, vinylpyridine copolymer, and nonionic ones. Examples include starch, water-soluble urea resin, polyacrylamide, and polyoxyethylene. In general, the higher the degree of polymerization of a polymer flocculant, the better the flocculation effect, and the amount added is 0.3 to 0.3 to the solid content of the sludge.
A suitable amount is about 1.5% by weight, preferably about 0.5 to 1% by weight. If the amount added is too large, the cohesiveness will decrease on the contrary. The amount to be added is determined by considering the following matters.

■) Select a suitable polymer flocculant depending on the type of sludge.

2) It increases or decreases in proportion to the solid content in the sludge.

For example, water content: 99.8% by weight...0.6-0.7% by weight Water content: 97.0% by weight...0.5% by weight3) In particular, the content of organic matter in sludge and the properties of sludge Determined by

4) If the amount added is too large, the cohesiveness will actually decrease,
In addition, the polymer flocculant adheres to the mesh of the screen of the screen drum and other mechanical parts, causing clogging and other malfunctions, and also from the viewpoint of economy, the use of the polymer flocculant should be somewhat limited.

The mixture of aggregated particles and wastewater is separated by a solid-liquid separation screen 40.
The material is guided to one end and transported to the kneading machine 50 while being dehydrated. - The solid-liquid separation screen 40 may have the following structure as long as it can continuously separate the aggregated particles and liquid, but in the illustrated embodiment, it is shown as a rotating screen drum. . Here, the four-turn screen drum may have a structure in which spiral blades are provided on the inner surface of a cylindrical screen drum. Such a structure is known as a continuous roaster, and can be thought of as a larger version of a roaster. Therefore, its details are not shown. As the rotating screen drum rotates, the mixture of coagulated particles and sewage is dehydrated while being conveyed by the spiral blades and discharged from the other end. As can be seen from the comparison of Figure 1a and b, the typical water content of the aggregated particles after dehydration by the squeezing means in the conventional method is 75 to 80%, and after dehydration by the rotating screen drum in the method of the present invention. The moisture content of the aggregated particles is about 90 to 92%.

In addition, as a solid-liquid separation screen, a screen belt,
Alternatively, a vibrating screen belt or the like may be used.

However, rotating screen drums are superior in terms of equipment costs and maintenance costs.

The dehydrated agglomerated particles discharged from the rotating screen drum 40 are received in the mixer 50, kneaded, and finely divided. Since the dehydrated aggregated particles are in the form of a paste, the kneader 50 is preferably of a type that grinds and kneads the dehydrated aggregated particles between two opposing surfaces. Here, the term "fragmentation" refers to loosening the filth particles aggregated by the flocculant, and does not mean pulverizing large filth particles into small pieces. As a result of this fragmentation, a portion of the water trapped in the aggregated dirt particles is released, and a film of calcium hydroxide, which will be described later, is formed around the fragmented dirt particles.

Powder is supplied to the kneading ta 50 from a powder storage tank 60 . The powder contains at least quicklime and water-insoluble particles. Calcium carbonate is preferred as the water-insoluble particles. Generally, the powder may be composed of only quicklime and water-insoluble particles, but in this case, the mixing ratio of quicklime and water-insoluble particles may generally be 40:60 to 60:40. However, it is desirable to adjust the amount of quicklime mixed according to the water content of the dehydrated aggregated particles introduced into the kneader 50. Specifically, when the moisture content of the dehydrated aggregated particles is 90% or more, it is about 60 to 50% of the total amount of the powder, and when the moisture content of the dehydrated aggregated particles is 85% or less, it is about 60 to 50% of the total amount of the powder. It should be about 50-30% of the total amount. The quicklime composition should be adjusted when the temperature of the mixture after adding the powder is 23~23℃.
The aim is to stay within the 35°C range. If the temperature of the mixture becomes too high, ammonia nitrogen is released, resulting in the generation of malodors and a reduction in the fertilizer value of the final treatment. Furthermore, if the amount of quicklime added to the solid content of the dehydrated aggregated particles is too large, the pH of the final treated product will become too high, causing problems in its use as fertilizer. On the other hand, the amount of water-insoluble particles blended is approximately 60 to 40% of the total amount of the powder. Therefore, when the moisture content of the dehydrated aggregated particles is low, the amount of quicklime should be 40 to 30% of the total amount of the powder, and MgO, S
It is preferable to add i02, MnO, etc. in an amount of 30% or less. Thereby, it is possible to reduce the rise in temperature during addition, suppress the rise in pH of the final treated product, and increase the fertilizing effect of the final treated product.

The amount of the powder agent to be added may generally be about 3 to 8% by weight based on the total amount of dehydrated agglomerated particles fed to the kneader. However, it is desirable to adjust the additive depending on the object to be treated. Specifically, when the target to be treated is general sewage sludge, the amount of powder added is around 6'%, when the target is urine sludge, it is around 8-10%, and when the target is livestock manure sludge, the amount of powder added is around 6'%. is desirably about 10 to 15%.

Thus, the dehydrated agglomerated particles are kneaded tl! ! 50 and mixed uniformly with the powder.

When added as a powder, quicklime exerts biological, chemical, and physical effects on sludge particles and malodorous substances in sewage.

Biological effects include p of sludge particles and sewage mixtures.
Increase the H value (usually pHIo.45 or higher),
This kills various bacteria (E. coli, putrefactive bacteria, etc.). This contributes to countermeasures against bad odors. However, the pH
An increase in the value angle increases the pH value of the final treatment, creating problems in its use as fertilizer.

In addition, as for chemical effects, quicklime reacts with water to produce calcium hydroxide (slaked lime), which reacts with malodorous substances and other chemical substances.

For example, an organic acid having a carboxyl group reacts in the following manner, contributing to the deodorizing effect and producing water.・・・・・・
・・・・・・・・・・・・・■Also, substances with hydroxyl groups react as shown below, and not only have a deodorizing effect, but also produce water.

・・・・・・・・・・・・・・・・・・■ Also, hydrogen sulfide (produced by protein decay), which is a malodorous substance, is produced as follows: 2H2S + Ca(OH)z →CaS2
+ Reacts like 2H20, providing deodorizing effect and producing water.・・・・・・・・・・・・・・・・・・
■Methyl mercabutane (CH.SH) as a malodorous substance
is 2CH. SH+Ca (OH). → (CH.S),
Ca+2H. It reacts as shown in ○, providing a deodorizing effect and producing ice.・・・・・・・・・・・・・・・・・・
■Methyl disulfide [(CH3)! as a malodorous substance! S,]
is (cHs)xs* + Ca (OH)z +
aH! O - (C Hs) zc a + 6
Hz? It reacts as shown in the following, and not only has a deodorizing effect, but also produces hydrogen gas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

On the other hand, ammonia (NHS), which is a malodorous substance,
Trimethylamine [(CH3)iN], etc. do not react with calcium hydroxide. In order to deodorize or deodorize these substances, it is necessary to use other chemicals.

Other drugs include hypochlorite. Sulfuric acid. Examples include hydrochloric acid. Generally, these devices suck air from a sealed odor source and release it below the surface of the chemical solution for absorption.

For example, hypochlorite reacts with the following malodorous substances in the following manner.

NH, + NaOCα- N, + NaCI2
+ H,0(CH3)3N + NaOCI
2 →N, + NaCQ+ H201-12s
+ NaOH-hNa2S + HzONa
zS + NaOCQ −* Na=SO4
+ NaCQ or Na,S + NaOCQ-*
S + NaCQ + NaOHCHsS
H + NaOCI2 → CH3SO3H
+ HCQ (CH.). S2+ NaOCI
2-CH. SO3H + HCQCH. CH
By physical adsorption of O, CH, COOH, sulfuric acid, and hydrochloric acid react with, for example, the following malodorous substances as shown below.

N.H. + H2SO, → (NH.) So. N
H3 + HCQ → NH4CI2(CHI)3
N + H, So. → (CHs)sN-H!
SO4(CHs) 3N + HCQ → (C
H3) sN-HCQ (Adsorption reaction) As a physical action, quicklime precipitates from the finely divided particles I; reacts with water and the water contained in the particles to become calcium hydroxide (slaked lime), A film is formed on the surface of the sludge particles. Similarly, water-insoluble particles also adhere to the surface of sludge particles. The deposited calcium hydroxide film reacts with carbon dioxide gas in the air and becomes calcium carbonate, forming a water-insoluble solid film. The dirt particles are thus encapsulated by the water-insoluble solid film, allowing water to flow out or evaporate through the interstices. The heat of reaction between quicklime and water helps evaporate the water. Furthermore, the sludge particles wrapped in the solid film are not easily re-sludged by irrigation such as rainwater.

Since the filtrate filtered in the rotating screen drum is not force-filtered by pressing, the COD and BOD values of the filtrate are quite low and can even be directly discharged into rivers.

An embodiment of the method and system of the present invention has been described above in detail, and data on sewage treatment using the system of the present invention and data on sewage treatment using a conventional system will be compared and shown below.

In Table 1, the weight of waste after treatment (%) is the percentage of the total weight of waste after treatment to the total weight of sewage input into the water storage tank l1, and the weight of water required to be treated in the purification layer (%).
%) is the percentage of the total weight of water that needs to be treated in the purification layer 30 with respect to the total weight of sewage input into the water storage tank 1l, and weight (%) of water that does not require treatment Each represents the percentage of the weight of water that can be discharged directly from the rotating screen drum without the need for water treatment, relative to the total weight of wastewater.

It should be noted that these values are only typical examples, and it goes without saying that if the water content of wastewater changes, the water content in each step will also change.

A comparison of the properties of waste after treatment by the method of the present invention and the conventional method is shown in the table below.

Escherichia coli Yes No Odor intensity (source) 5 2-2.5 Odor intensity: 20m downwind) 3 1 Re-sludge formation
Yes No Hydrophobicity No Yes Organic viscosity Yes
None Heavy metals No adsorption properties
Adsorption property In addition, in Table 2, E. coli was tested by diluting the sample, culturing it, and counting the number of colonies according to a conventional method. Although Escherichia coli is not the only bacteria contained in the waste, most bacteria die under highly alkaline conditions, so Escherichia coli was used as a representative for measurement. The measurement results are shown in Table 3.

Waste weight after treatment (%) 0.06666
0.022218 Required water treatment weight in purification layer (%
) 99.93334 99.3334 Weight of water not required for ice treatment (%) 0 0.6510
480.044442 0.599940 0.651048 Table 3 o. oo o O. 37 50 0.74 100 1.11 150 1.48 200 1.86 250 2.23 300 2.97 350 6.2 25 X 10' 7.45 50 x 10" 7.90 27 X 10" 8.92 23 X 10' 9.02 134 X 10" 9.68 24 X 10" 10.45 0 10.60 0 0.0 80.0 89.2 90.8 94.6 99.0 100. O too. In Table 2, odor was measured by the following method.

1) Measurement point: No. l: Offensive odor source, No. 2: 5m point downwind from the source, No. 3: 10m point downwind from the source, No. 4: Same 15m point, No. 5: Same 20m point However, since the temperature of the source is high, a glass tube of 30Φ x 1000m/m was inserted into the flue and the sample was taken at a position 500m/m from the tip of the flue (gas temperature 90℃).

2) Weather conditions: Weather: Sunny, sometimes cloudy Temperature: 17℃ Humidity: 70% Atmospheric pressure 2 1031mb Wind direction: W Wind speed 20.5-4m/s 3) Measurement results: The measurement results are shown in Table 4.

@ 4 Measurement position Shame. l No. 2 items
(1) (2) Ammonia 6.40 5.46
0.42 Methyl I Kabutane 0.0
006 0.0005 <0.0001 Hydrogen sulfide 0.0020 0.0010 0.0003
Methyl sulfide 0.0003 0.000
2 <0.0001 Methyl disulfide <0.00
01 <0.0001 <0.0001 Trimethylamine 0.016 0.009
0.011 (unit: ppm) Disgrace. 3 No. 4 1.06 <0.01 <0.0001 <0.0001 0.0002 0.0001 <0.0001 <0.0001 <0.0001 <0.0001 0.010 0.007 Measurement and evaluation are carried out by the Environment Agency Notification No. 9 (
Measurements and evaluations were made according to the standards established in May 30, 1972).

In addition, regarding resludge formation, the waste after treatment is irrigated with No. 5 0,24 <0.0001 (LOOOI <o. ooot <o. ooooi O. 011 I washed it with water and poked it with a stick to observe its condition.

Hydrophobicity was determined by placing a sample in a beaker, pouring water over it, stirring it, and determining whether the sample was suspended or floated in the water.

The adsorption of heavy metals was measured by treating the aqueous wiping waste liquid from a printing factory using the conventional method and the method of the present invention, and then measuring the waste in accordance with the method set forth in Environment Agency Notification No. 13.

Effect of the invention The effects of the present invention are as follows.

(1) Waste is easy to release moisture after treatment, and by simply leaving it in a pile, the volume is 1/2 to 1/2 of that of conventional methods.
It can be set to 5.

Furthermore, when disposed of by incineration, the cost of incineration can be significantly reduced since the water content is extremely low.

(2) The waste after treatment does not turn into sludge again, contains few bacteria, and has almost no odor, so it can be piled up and cured.

(3) System equipment costs, maintenance, and management costs can be significantly reduced.

(4) Since it does not turn into sludge again and contains organic matter and calcium hydroxide, it can be used as fertilizer and soil improvement medicine.

(5) Since it has adsorption properties for heavy metals, it can be used not only for treating domestic wastewater but also industrial wastewater or mixed wastewater of domestic and industrial wastewater. However, if the wastewater contains environmental pollutants such as heavy metals, it is desirable to incinerate the wastewater, but even in that case, there are the advantages described in (1) above.

[Brief explanation of drawings]

FIGS. 1a and 1b are flowcharts of the conventional method and the method of the present invention, respectively. FIG. 2 is a layout diagram showing the system of the present invention, and FIG. 3 is a layout diagram showing the conventional system. Explanation of symbols 10: storage tank, ll: water tank, l2: concentration tank, 20: II
I collection tank, 2l: stirring means, 22: polymer flocculant storage tank, 2
3: Water supply source, 24: 25: Stirring means, 30: Septic tank, 3L: Flow rate adjustment tank, 32: Aeration tank, 33: Sedimentation tank, 34: Disinfection/discharge layer, 40: Rotating screen drum,
50: Kneading machine, 60: Powder storage tank,

Claims (1)

[Claims] [1] Sedimentation and concentration of sewage/sludge in a settling tank,
Mix a polymer flocculant with thickened sludge, dehydrate the mixture,
In the sewage/sludge treatment method to be disposed of, raw sludge or thickened sludge should be treated with 0.3% of its solids content.
~1.5% by weight, preferably 0.5-1% by weight of a polymer flocculant is added, mixed uniformly to flocculate the sludge particles, and then dehydrated using a solid-liquid separation screen. By adding and kneading a powder containing quicklime (CaO) and water-insoluble particles to coagulated sludge, the coagulated particles are finely divided and water is separated, and quicklime and non-water-soluble particles are added to the suspension of the finely divided particles. It is characterized by homogeneously stirring a powder containing water-soluble particles to form a solid film of calcium hydroxide and water-insoluble particles on the surface of the finely divided particles to form an aggregate of hydrophobic finely divided particles. sewage/sludge treatment method. [2] The method according to claim 1, characterized in that the finely divided particle aggregate covered with a solid film of calcium hydroxide and water-insoluble particles is dried by releasing moisture. sewage treatment method. [3] The method according to claim 1 or 2, wherein the water-insoluble particles are calcium carbonate (CaCO_3). [4] A stirring tank that introduces and stirs sludge and a polymer flocculant to produce flocculated particles, one end that receives the sludge-flocculant mixture containing the flocculated particles from the stirring tank, and dewaters the received mixture. a solid-liquid separation screen for discharging from the other end of the solid-liquid separation screen; a storage tank for storing a powder containing quicklime and water-insoluble particles; and a storage tank for storing a powder containing quicklime and water-insoluble particles; Powders containing water-soluble particles are each received from the storage tank, kneaded, the agglomerated particles are finely divided, the finely divided particles are separated from water to form a suspension of finely divided particles, and A sludge treatment system comprising: a kneading means for homogeneously mixing particles and the powder agent. [5] The sludge treatment system according to claim 4, comprising: a settling tank for storing sewage to settle sludge and supplying the sludge to the stirring tank; receiving the kneaded material from the kneading means; curing; A sewage treatment system further comprising: curing equipment for drying.