WO2014021228A1 - 汚泥の処理法及び処理装置 - Google Patents

汚泥の処理法及び処理装置 Download PDF

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Publication number
WO2014021228A1
WO2014021228A1 PCT/JP2013/070370 JP2013070370W WO2014021228A1 WO 2014021228 A1 WO2014021228 A1 WO 2014021228A1 JP 2013070370 W JP2013070370 W JP 2013070370W WO 2014021228 A1 WO2014021228 A1 WO 2014021228A1
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Prior art keywords
sludge
polymer flocculant
mixed
stirring
stirrer
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PCT/JP2013/070370
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English (en)
French (fr)
Japanese (ja)
Inventor
智之 森田
萩野　隆生
倫也 板山
加藤　宏行
築井　良治
昌次郎 渡邊
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水ｉｎｇ株式会社
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Application filed by 水ｉｎｇ株式会社 filed Critical 水ｉｎｇ株式会社
Priority to JP2014528125A priority Critical patent/JP5837694B2/ja
Priority to CN201380040615.0A priority patent/CN104507879B/zh
Publication of WO2014021228A1 publication Critical patent/WO2014021228A1/ja

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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/14—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents
    • C02F11/147—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents using organic substances
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/50—Mixing liquids with solids
    • B01F23/59—Mixing systems, i.e. flow charts or diagrams
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
    • B01F27/80—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F2215/00—Auxiliary or complementary information in relation with mixing
    • B01F2215/04—Technical information in relation with mixing
    • B01F2215/0409—Relationships between different variables defining features or parameters of the apparatus or process
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/001—Upstream control, i.e. monitoring for predictive control
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/005—Processes using a programmable logic controller [PLC]
    • C02F2209/006—Processes using a programmable logic controller [PLC] comprising a software program or a logic diagram

Definitions

  • the present invention relates to a sludge treatment method and a treatment apparatus.
  • the present invention relates to a treatment method for aggregating sludge and a treatment apparatus used therefor in a dehydration treatment for reducing the volume of sludge discharged from a wastewater treatment facility or a water purification treatment facility.
  • the sludge dehydration treatment is generally composed of a coagulation step of coagulating sludge using a coagulant and a dehydration step of dehydrating the coagulated sludge using a dehydrator.
  • the success or failure of sludge dehydration depends largely on how effectively it can be agglomerated by a flocculant.
  • Patent Document 1 a first polymer flocculant having a charge opposite to the charge of sludge is added to sludge, and the first stirring is performed.
  • the first stirring does not generate floc, or
  • a sludge dewatering method characterized by strong stirring so that the generated floc diameter is 2 mm or less.
  • Patent Document 2 in coagulating organic sludge using an amphoteric polymer flocculant, the sludge and the amphoteric polymer flocculant are mixed in the first stage treatment. A part is brought into contact under relatively strong stirring, and the first-stage treated sludge and the remainder of the amphoteric polymer flocculant are brought into contact under relatively weak stirring in the second-stage treatment. And a method for coagulating sludge is disclosed.
  • JP-A-11-57800 (patent document 3), an inorganic flocculant and an amphoteric polymer as a first polymer are added to organic sludge and vigorously stirred, and an amphoteric polymer is added as a second polymer.
  • a sludge dewatering method characterized by performing pressure dehydration after slow stirring.
  • Patent Document 4 After adding inorganic flocculant A to turbid water and stirring and mixing, organic flocculant B is added thereto, and the floc L is stirred slowly.
  • a method for coagulating and dewatering turbid water is disclosed, characterized in that the floc L is added, the inorganic flocculant C is added to the floc L, stirred and mixed, the floc L is decomposed or broken, and then dewatered. Yes.
  • the preferred agitation conditions vary depending on the type and concentration of the sludge. I had the problem of being difficult.
  • an object of the present invention relates to a method of aggregating sludge by a two-stage agitation process with different rotation speeds, and it is possible to easily find preferable agitation conditions even when the type and concentration of sludge changes in a site where the sludge is agglomerated. It is possible to provide a new sludge treatment method and treatment apparatus capable of effectively reducing the water content of the finally obtained dehydrated cake.
  • the first polymer flocculant solution is added to the sludge as an object to be treated, and the sludge and the first polymer flocculant solution are mixed and mixed by at least one stirrer.
  • a mixed sludge preparation process for preparing sludge; Sludge treatment comprising: adding a second polymer flocculant solution to the mixed sludge, and mixing the mixed sludge and the second polymer flocculant solution to form a floc floc forming step.
  • the relationship among the power consumption (kW) A of the stirrer, the sludge treatment amount (kg / h) B of the sludge, and the sludge concentration (g / L) C is as follows:
  • the sludge treatment method is characterized in that the mixing is performed so that the formula (1) is satisfied.
  • Formula (1) (Power consumption A x Sludge concentration C) / Sludge treatment amount B 0.15 to 1.10.
  • the present invention also includes, as an example of a sludge treatment apparatus for carrying out such a sludge treatment method, means for adding a solution of the first polymer flocculant to the sludge, and at least one stirrer, And a mixed sludge preparation device for preparing a mixed sludge by mixing the first polymer flocculant solution, means for adding the second polymer flocculant solution to the mixed sludge, and the mixed sludge;
  • the present invention proposes a sludge treatment apparatus comprising: a flocculant floc forming apparatus that mixes the second polymer flocculant solution to form a floc floc.
  • Polymer flocculants generally have high viscosity, so it is difficult to distribute the flocculant uniformly to the sludge details.
  • the polymer flocculant by stirring in the mixed sludge preparation step, the polymer flocculant can be uniformly dispersed to the sludge details, and by neutralizing the sludge surface charge and adsorbing or crosslinking the polymer. Aggregation can be performed simultaneously.
  • the next flocculation floc forming step by mixing the polymer flocculant with the mixed sludge obtained in the mixed sludge preparation step, a large flocculation floc can be formed, and the flocculated sludge having good filterability can be formed. Can be formed. As a result, the moisture content of the finally obtained dehydrated cake can be effectively reduced, and further the amount of the polymer flocculant used can be reduced.
  • the power consumption A (kW) of the stirrer and the sludge treatment amount of sludge as the object to be treated (kg / H)
  • the moisture content of the dewatered cake can be effectively reduced. Therefore, it is possible to easily set appropriate stirring conditions at the site where the sludge is aggregated.
  • the sludge treatment method or sludge treatment apparatus proposed by the present invention not only can the amount of the polymer flocculant used for aggregating the sludge as an object to be treated be reduced, but also after dehydration. Since the moisture content of the obtained dehydrated cake can be reduced, the amount of waste can be reduced.
  • the sludge treatment method according to the present embodiment includes adding a first polymer flocculant solution to sludge as an object to be treated, and using at least one stirrer, the sludge A mixed sludge preparation step (referred to as “first stirring step” in the present processing method) for mixing the first polymer flocculant solution with the first polymer flocculant solution, and a second polymer flocculant solution Is added to the mixed sludge, and the mixed sludge and the second polymer flocculant solution are mixed by at least one stirrer to form an agglomerated floc (in this treatment method, “second A sludge treatment method having a “stirring step”.
  • the sludge that can be treated in this treatment method may be either organic sludge or inorganic sludge.
  • organic sludge examples include organic sludge generated in sewage treatment, human waste treatment, and various industrial wastewater treatment. More specifically, first sedimentation basin sludge, surplus sludge, anaerobic digested sludge, aerobic digested sludge, septic tank sludge, digested detachment liquid and the like can be mentioned.
  • the organic sludge may contain an inorganic substance.
  • the inorganic sludge examples include inorganic sludge generated in water purification treatment, construction wastewater treatment, and various industrial wastewater treatment.
  • the sludge generated in the water purification treatment is sludge discharged from a settling pond, a waste mud pond, a concentration tank, or the like in the water purification treatment facility.
  • the inorganic sludge may contain organic matter.
  • organic sludge is preferable.
  • non-dewatering anaerobic digested sludge is particularly preferable.
  • First stirring step the solution of the first polymer flocculant is added to the sludge as the object to be treated, and the rotation speed of the stirrer is set by at least one stirrer set to be higher than usual. It is preferable to prepare a mixed sludge by mixing the sludge and the solution of the first polymer flocculant.
  • High-speed agitation makes it possible to uniformly disperse the polymer flocculant in the sludge and distribute the polymer flocculant to the details of the sludge, thereby neutralizing the surface charge of the sludge and adsorbing or crosslinking the polymer. Aggregation can be performed simultaneously.
  • the inorganic flocculant is added to the sludge and stirred, only the surface charge of the sludge is neutralized, so by adding the polymer flocculant and stirring at high speed, a larger and more dense flocculant floc can be formed, A strong coagulated sludge with good filterability can be formed.
  • first polymer flocculant any of anionic polymer flocculants, nonionic polymer flocculants, cationic polymer flocculants and amphoteric polymer flocculants can be used.
  • anionic polymer flocculants nonionic polymer flocculants
  • cationic polymer flocculants cationic polymer flocculants
  • amphoteric polymer flocculants When treating organic sludge, it is particularly preferable to use a cationic polymer flocculant or an amphoteric polymer flocculant.
  • anionic polymer flocculant examples include sodium polyacrylate, a copolymer of sodium acrylate and acrylamide, polysodium methacrylate, a copolymer of sodium methacrylate and acrylamide, and the like.
  • nonionic polymer flocculants examples include polyacrylamide and polyethylene oxide.
  • cationic polymer flocculants examples include acrylate polymer flocculants (also referred to as “DAA polymer flocculants”), methacrylate polymer flocculants (also referred to as “DAM polymer flocculants”), and amide groups. , Nitrile groups, amine hydrochlorides, formamide groups, and the like, and polyvinylamidines (also referred to as “amidine polymer flocculants”), polyacrylamide Mannich modified products, and the like.
  • DAA polymer flocculants also referred to as “DAA polymer flocculants”
  • methacrylate polymer flocculants also referred to as “DAM polymer flocculants”
  • amide groups examples include amide groups. , Nitrile groups, amine hydrochlorides, formamide groups, and the like, and polyvinylamidines (also referred to as “amidine polymer flocculants”), polyacrylamide Mannich modified products, and the like.
  • Examples of the DAA polymer flocculant include a polymer of a quaternized product of dimethylaminoethyl acrylate, a copolymer of a quaternized product of dimethylaminoethyl acrylate and acrylamide, and the like.
  • Examples of the DAM polymer flocculant include a polymer of a quaternized product of dimethylaminoethyl methacrylate and a copolymer of a quaternized product of dimethylaminoethyl methacrylate and acrylamide.
  • amphoteric polymer flocculants include, for example, dimethylaminomethyl acrylate quaternized products of acrylamide and acrylic acid, dimethylaminomethyl methacrylate quaternized products of acrylamide and acrylic acid, and the like. Can do. However, the above is an example and is not limited thereto.
  • the molecular weight of the first polymer flocculant is preferably 4.5 million or more. A more preferable molecular weight is 5 million or more.
  • the molecular weight here is an average molecular weight determined by a viscosity method.
  • the polymer flocculant is dispersed in sludge by high-speed stirring, the molecular chain of the polymer flocculant may be broken by high-speed stirring. Therefore, if the molecular weight of the polymer flocculant is too low, the polymer flocculant aggregates. Power is weakened. For this reason, by using a polymer flocculant having a molecular weight of 4.5 million or more, even if the molecular chain is broken by high-speed stirring, a certain degree of cohesive force of the polymer flocculant can be maintained.
  • the viscosity of the first polymer flocculant is preferably 150 mPa ⁇ s or more, particularly 175 mPa ⁇ s or more, and more preferably 200 mPa ⁇ s or more.
  • the viscosity at this time is a value measured by dissolving the polymer flocculant in pure water at 2 g / L and using a B-type viscometer at a rotation speed of 25 ° C. and 60 rpm.
  • injection amount of the first polymer flocculant When the molecular weight of the first polymer flocculant is 4.5 million or more, the injection amount of the first polymer flocculant is 45 of the total injection amount of the first polymer flocculant and the second polymer flocculant. It is preferable to adjust and add so that it may be -95 mass%, and it is preferable to adjust and add so that it may occupy 50-95 mass%, especially 55-90 mass% especially. If the proportion of the polymer flocculant injected in the first stirring step is too high, the amount of polymer flocculant added in the second stirring step will be too small, and the flocs may not grow.
  • the filterability deteriorates in the concentration process and the dehydration process.
  • the ratio of the amount of the polymer flocculant injected in the first stirring step is too low, the proportion of the polymer flocculant uniformly dispersed in the sludge by the high-speed stirring decreases in the first stirring step. The effect will be reduced. Therefore, the amount of the polymer flocculant injected in the first stirring step is controlled to 45 to 95% of the total amount injected, so that the polymer flocculant can be uniformly dispersed in the sludge and the aggregate flocs can be grown. it can.
  • Examples of the solvent in the first polymer flocculant solution include pure water, tap water, industrial water, ground water, treated water for various wastewater treatment, seawater, and the like. From the viewpoint of exerting it, pure water is preferable. This also applies to the second polymer flocculant solution. On the other hand, from the viewpoint of economy, tap water, industrial water, ground water, and treated water for various wastewater treatment are preferable. This also applies to the second polymer flocculant solution.
  • the concentration of the polymer flocculant in the first polymer flocculant solution may be 1 to 3 g / L, but is preferably 3 g / L or more, more preferably 5 g / L or more, and still more preferably. It is 10 g / L or more.
  • the polymer flocculant solution is generally prepared at 1 to 3 g / L, and usually a polymer flocculant solution of 3 g / L or more is used. Absent. The reason for this is that when the polymer flocculant concentration is 3 g / L or more, the polymer flocculant solution becomes highly viscous.
  • the rotational speed of the stirrer used in the conventional flocculation tank (about 10 to 500 rpm). This is because it is difficult to uniformly disperse the polymer flocculant in the sludge.
  • the polymer flocculant can be uniformly dispersed in the sludge even when a high concentration solution of 3 g / L or more is used. As a result, there is an advantage that the amount of dissolved water of the polymer flocculant can be reduced.
  • Another advantage of using a high-concentration polymer flocculant solution is that the polymer flocculant concentration in the sludge containing the polymer flocculant can be increased, so the amount of polymer flocculant injected can be reduced.
  • the water content of the dehydrated cake after the dehydration treatment can be reduced. For example, when 200 mL of a 2 g / L polymer flocculant solution is injected into 1 L of sludge (0.4 g as a polymer flocculant), the concentration of the polymer flocculant in the sludge is 333 mg / L.
  • the concentration of the polymer flocculant in the sludge is 385 mg / L.
  • the concentration of the polymer flocculant therein can be increased, the amount of the polymer flocculant injected can be reduced, and the water content of the dehydrated cake after the dehydration treatment can be reduced.
  • stirring is preferably performed at a high speed of 1000 rpm or more.
  • a more preferable rotation speed is 2000 rpm or more.
  • An even more preferable rotation speed is 3000 rpm or more.
  • the stirring time may be shortened, so there is no particular upper limit on the rotational speed, but at present, it has been confirmed experimentally effective up to 15000 rpm.
  • the first stirring step it is preferable to uniformly disperse the polymer flocculant in the sludge and to distribute the polymer flocculant to the details of the sludge.
  • uniformly dispersing the polymer flocculant in the sludge useless polymer flocculant can be reduced, and the amount of the polymer flocculant injected can be reduced.
  • the flocculent sludge becomes dense by spreading the polymer flocculant to the details of the sludge, the water content of the dewatered cake after the dewatering treatment can be reduced.
  • the polymer flocculant solution is a high-viscosity liquid, and it is difficult to uniformly disperse the polymer flocculant in the sludge at the rotational speed of the stirrer (about 10 to 500 rpm) used in the conventional flocculation tank.
  • the polymer flocculant could not be distributed to the details of the sludge. For this reason, the injection amount of the polymer flocculant was increased and the moisture content of the dehydrated cake was deteriorated.
  • the polymer flocculant in high-speed stirring, the polymer flocculant can be uniformly dispersed in the sludge, and the polymer flocculant can be distributed to the details of the sludge. For this reason, the injection amount of the polymer flocculant can be reduced, and the water content of the dehydrated cake can be reduced.
  • the rotation speed at the time of stirring in high-speed stirring at 1000 rpm or more according to the kind of sludge, the property of sludge, the molecular weight of the polymer flocculant, the dissolution concentration of the polymer flocculant, and the like.
  • the relationship between the power consumption A (kW) of the stirrer, the sludge treatment amount (kg / h) B of the sludge, and the sludge concentration (g / L) C is It is important to adjust the stirring conditions so that the following formula (1) is satisfied.
  • concentration TS.
  • Formula (1) (Power consumption A x Sludge concentration C) / Sludge treatment amount B 0.15 to 1.10.
  • the ratio (B / C) of sludge treatment amount (kg / h) B of sludge to sludge concentration (g / L) C is less than 3.5, the value of the above formula (1) is 0.40.
  • it is preferably 0.50 or more or 1.00 or less, more preferably 0.60 or more or 0.00. It is particularly preferable to adjust to 90 or less.
  • the ratio (B / C) of sludge treatment amount (kg / h) B of sludge to sludge concentration (g / L) C is significantly large, that is, 3.5 or more
  • the above formula (1) Is preferably adjusted to 0.15 to 0.40, and in order to more effectively reduce the water content of the dehydrated cake, it is preferably 0.20 or more or 0.35 or less, and more preferably 0. It is particularly preferable to adjust to 20 or more or 0.30 or less.
  • the water content of the dehydrated cake is effectively set by setting the stirring conditions so that the relationship of the above formula (1) is established in the first stirring step. It was found that it can be reduced.
  • the power consumption A (kW) of the stirrer can be adjusted mainly by setting the stirring speed if the same stirrer is used. It is preferable to set the stirring speed so that the above formula (1) is established according to the sludge treatment amount of sludge, and it is preferable to control the value of the formula (1) to be constant among them.
  • the stirring time in the first stirring step is preferably 20 seconds or less, particularly preferably 1 second to 20 seconds, more preferably 1 second to 15 seconds. Seconds, even more preferably 1 to 10 seconds. If the stirring time by high-speed stirring is too long, the molecular chain of the polymer flocculant is broken to such an extent that the cohesive force of the polymer flocculant is weakened. For this reason, by controlling the stirring time to 20 seconds or less, the polymer flocculant is uniformly dispersed in the sludge without weakening the cohesive force of the polymer flocculant, and the polymer flocculant is spread to the details of the sludge. be able to.
  • the mixing may be further performed such that the power consumption (kW) per volume (L) of the stirring unit in the stirrer is 1.0 (kW / L) or more. Even more preferred. That is, in the first stirring step, the water content of the dewatered cake can be further reduced by setting the power consumption per stirring unit volume to 1.0 or more. From this viewpoint, it is more preferable that the power consumption (kW) per volume (L) of the stirrer in the stirrer is 1.5 (kW / L) or more or 5.0 (kW / L) or less. More preferably, it is 0.0 (kW / L) or more or 4.0 (kW / L) or less.
  • the volume of the stirring part in a stirrer means the volume of the area
  • the stirrer has a stirring tank, it refers to the volume of the stirring tank.
  • region part where the stirring force of a stirring blade acts is said.
  • a high-speed stirrer composed of a stirring blade, a shaft and a motor, a high-speed stirrer composed of a rotor, a stator and a motor may be used, or an in-line mixer. May be stirred at high speed.
  • An in-line mixer is a mixer built into piping.
  • An in-line mixer is also called a line mixer. The merit of the in-line mixer is that the mixer is hermetically sealed, so if there are two pumps for the sludge and the polymer flocculant upstream, the liquid can be sent downstream.
  • the second polymer flocculant is added to the mixed sludge prepared in the first stirring step, and at least one stirring set to a lower stirring speed (also referred to as “normal stirring”) than in the first stirring step.
  • the mixed sludge and the second polymer flocculant solution are mixed by a machine to form a floc floc.
  • the polymer flocculant can be uniformly dispersed to the sludge details, and the surface charge of the sludge can be neutralized and the polymer can be simultaneously adsorbed or aggregated by a crosslinking action.
  • a large coagulation floc can be formed by relatively slowly stirring and mixing the polymer flocculant with the mixed sludge obtained in the first stirring step, and the filterability is good. Agglomerated sludge can be formed.
  • the second polymer flocculant As the second polymer flocculant, the same polymer flocculant as described above in the item of the first polymer flocculant can be used. In this case, as the second polymer flocculant, the same type of polymer flocculant as the first polymer flocculant can be used, but a different type of polymer flocculant can be used. From the viewpoint of sharing the polymer flocculant dissolution tank, it is preferable to use the same type of polymer flocculant as the first polymer flocculant as the second polymer flocculant.
  • the concentration of the polymer flocculant in the second polymer flocculant solution may be 1 to 3 g / L, but is preferably 3 g / L or more, more preferably 5 g / L or more, and still more preferably. It is 10 g / L or more.
  • the rotational speed at the time of stirring in the second stirring step is preferably a general rotational speed in a conventional sludge aggregation apparatus, that is, 10 to 500 rpm.
  • the reason is that in the second stirring step, the polymer flocculant needs to be gently brought into contact with the mixed sludge prepared in the first stirring step to grow the flocs floc.
  • the rotation speed at the time of stirring in the second stirring step is more preferably 20 rpm or more or 400 rpm or less, and more preferably 30 rpm or more or 300 rpm or less.
  • the rotational speed at the time of stirring in the second stirring step is adjusted at 10 to 500 rpm according to the kind of sludge, the property of sludge, the molecular weight of the polymer flocculant, the dissolution concentration of the polymer flocculant, and the like. preferable.
  • the stirring time in the second stirring step that is, the time for mixing and stirring the second polymer flocculant solution and sludge is preferably 1 to 20 minutes.
  • the stirring time in the second stirring step is preferably 2 minutes or more and 15 minutes or less, and more preferably 3 minutes or more or 10 minutes or less.
  • a normal stirrer such as a stirrer including a stirring blade, a shaft, and a motor may be used, and the type is not particularly limited. Moreover, you may stir with an in-line mixer.
  • a dehydrator conventionally used for sludge dehydration such as a screw press dehydrator, a belt press dehydrator, a centrifugal dehydrator, a vacuum dehydrator, a filter press dehydrator, a multiple disk dehydrator, or the like can be used.
  • the mixed sludge and the second polymer flocculant solution may be mixed to form a floc floc and dehydrate.
  • the reaction tank is a rotating drum having a large number of holes, the mixed sludge and the second polymer flocculant solution can be mixed by the rotation of the reaction tank to form an aggregate floc and dehydrated. it can.
  • reaction tank is a rotating drum having holes at both ends
  • the apparatus is equipped with a screw conveyor inside the reaction tank
  • the reaction of the sludge and the second polymer flocculant is caused by the rotation of the reaction tank.
  • the dehydrated filtrate can be separated from the aggregated floc by centrifugal force and dehydrated.
  • the sludge treatment apparatus capable of carrying out this treatment method includes means for adding a solution of the first polymer flocculant to the sludge, and at least one stirrer, and the sludge and the first polymer.
  • a “mixed sludge preparation device” for mixing a flocculant solution to prepare a mixed sludge; means for adding a second polymer flocculant solution to the mixed sludge; and the mixed sludge and the second high sludge An apparatus for treating sludge provided with a coagulation floc forming apparatus that mixes with a solution of a molecular coagulant to form an aggregate floc can be mentioned.
  • a more preferable sludge treatment apparatus capable of carrying out this treatment method, means for adding the first polymer flocculant solution to the sludge, and at least one agitation set at a rotation speed of 1000 rpm or more
  • a mixing sludge preparation device for preparing a mixed sludge by mixing the sludge and the first polymer flocculant solution, and means for adding a second polymer flocculant solution to the mixed sludge,
  • an agglomerated floc forming apparatus comprising at least one stirrer whose rotation speed is set to 10 to 500 rpm, and mixing the mixed sludge and the second polymer flocculant solution to form an agglomerated floc;
  • FIG. 1 is a schematic view showing an example of an apparatus for carrying out the first embodiment.
  • the apparatus shown in FIG. 1 has a configuration in which a sludge supply pump 4, a sludge flow meter 12, a high-speed stirring tank 7, a normal-speed stirring tank 8, and a dehydrator 11 are sequentially connected to the downstream side in the sludge storage tank 1.
  • a first polymer flocculant dissolution tank 2 communicates with the high-speed stirring tank 7 via a first polymer flocculant pump 5, and a second polymer flocculant is disposed in the normal speed stirring tank 8.
  • a second polymer flocculant dissolution tank 3 is arranged in communication with the agent pump 6.
  • a control device 13 electrically connected to the sludge flow meter 12 is electrically connected to the high-speed stirrer 9 of the high-speed stirring tank 7.
  • sludge is first stored in the sludge storage tank 1, and the stored sludge is supplied to the high-speed stirring tank 7.
  • the first polymer flocculant solution is supplied from the first polymer flocculant dissolution tank 2 to the high-speed stirring tank 7 by the first polymer flocculant pump 5.
  • the sludge and the solution of the first polymer flocculant are mixed by the high-speed stirrer 9 to prepare mixed sludge.
  • the prepared mixed sludge is supplied from the high speed stirring tank 7 to the normal speed stirring tank 8.
  • the solution of the second polymer flocculant is supplied from the second polymer flocculant dissolution tank 3 to the normal speed stirring tank 8 by the second polymer flocculant pump 6.
  • the mixed sludge and the second polymer flocculant solution are mixed by the normal speed stirrer 10, and the mixed sludge is aggregated to form aggregated flocs.
  • the aggregated floc is dehydrated by the dehydrator 11.
  • the control device 13 reads the sludge treatment amount and sludge concentration of the sludge through the sludge flow meter 12, while reading the power consumption of the high-speed stirrer 9, and sets the stirring conditions, especially the rotation speed so that the above equation (1) is established. And can be controlled.
  • FIG. 2 is a schematic diagram showing another example of the apparatus different from the above example of the processing apparatus.
  • the apparatus shown in FIG. 2 has a configuration in which a sludge supply pump 4, a sludge flow meter 12, a high-speed stirring tank 7, a normal-speed stirring tank 8, and a dehydrator 11 are sequentially connected to the downstream side in the sludge storage tank 1.
  • a first polymer flocculant dissolution tank 2 communicates with the high-speed stirring tank 7 via a first polymer flocculant pump 5, and a second polymer flocculant is disposed in the normal speed stirring tank 8.
  • a second polymer flocculant dissolution tank 3 is arranged in communication with the agent pump 6.
  • the high-speed stirrer 9 of the high-speed agitation tank 7 is electrically connected to a control device 13 that is electrically connected to the sludge supply pump 4 and the sludge flowmeter 12.
  • the sludge treatment procedure in this apparatus is the same as that in the first treatment apparatus example.
  • the control device 13 is connected to the sludge supply pump 4 and the sludge flow meter 12, while reading the sludge treatment amount and sludge concentration of the sludge through the sludge flow meter 12, the power consumption of the high speed agitator 9 is read, Not only the stirring conditions but also the flow rate of the sludge supply pump 4 can be controlled so that the formula (1) is established.
  • FIG. 3 is a schematic diagram showing another example of the apparatus different from the above example of the processing apparatus.
  • the apparatus shown in FIG. 3 includes a sludge supply pump 4, a sludge flow meter 12, a high speed stirring tank 7 A, a first valve 14, a high speed stirring tank 7 B, a second valve 15, a normal speed stirring tank 8, and a dehydrator. 11 are arranged sequentially communicating downstream.
  • a first polymer flocculant dissolution tank 2 is communicated with the high-speed stirring tank 7A via the first polymer flocculant pump 5, and a second polymer flocculant is provided in the normal speed stirring tank 8.
  • the second polymer flocculant dissolution tank 3 is arranged in communication with the pump 6.
  • a bypass pipe 17 is installed between the high-speed stirring tank 7A and the first valve 14 and between the second valve 15 and the normal speed stirring tank 8, and the third valve 16 is provided in the middle of the bypass pipe 17. is set up.
  • the control apparatus 13 electrically connected to the said sludge flowmeter 12 is electrically connected to the high-speed stirrer 9A of the high-speed stirring tank 7A and the high-speed stirrer 9B of the high-speed stirring tank 7B.
  • this apparatus has the above-described configuration, when the sludge flow rate is small, the first valve 14 and the second valve 15 are closed, while the third valve 16 is opened, whereby the high-speed stirring tank 7A is used.
  • the mixed sludge mixed with the polymer flocculant can be supplied to the normal speed stirring tank 8 via the bypass pipe 17.
  • the first valve 14 and the second valve 15 are opened, and the third valve 16 is closed to mix the polymer flocculant and the sludge by high-speed stirring in the high-speed stirring tank 7A. Thereafter, the polymer flocculant and the sludge can be mixed again by high-speed stirring in the high-speed stirring tank 7B, and the obtained mixed sludge can be supplied to the normal-speed stirring tank 8.
  • FIG. 4 is a schematic diagram showing another example of the apparatus different from the above example of the processing apparatus.
  • the apparatus shown in FIG. 4 has a configuration in which a sludge supply pump 4, a sludge flow meter 12, a high-speed stirring tank 7, a normal-speed stirring tank 8, and a dehydrator 11 are sequentially connected to the downstream side in the sludge storage tank 1.
  • a first polymer flocculant dissolution tank 2 communicates with the high-speed stirring tank 7 via a first polymer flocculant pump 5, and a second polymer flocculant is disposed in the normal speed stirring tank 8.
  • a first polymer flocculant dissolution tank 2 is arranged in communication with the agent pump 6.
  • a control device 13 electrically connected to the sludge flow meter 12 is electrically connected to the high-speed stirrer 9 of the high-speed stirring tank 7.
  • the second polymer flocculant dissolution tank 3 is omitted in this apparatus, and the first polymer flocculant solution is fed by the first polymer flocculant pump 5.
  • the high-speed stirring tank 7 is supplied from the first polymer flocculant dissolution tank 2.
  • the first polymer flocculant solution is supplied from the first polymer flocculant dissolution tank 2 to the normal speed stirring tank 8 by the second polymer flocculant pump 6.
  • FIG. 5 is a schematic diagram showing another example of the apparatus different from the above example of the processing apparatus.
  • the apparatus shown in FIG. 5 has a configuration in which a sludge supply pump 4, a sludge flow meter 12, a high-speed stirring tank 7, a normal-speed stirring tank 8, and a dehydrator 11 are sequentially connected to the downstream side in the sludge storage tank 1. I have.
  • a control device 13 electrically connected to the sludge flow meter 12 is electrically connected to the high-speed stirrer 9 of the high-speed stirring tank 7.
  • the first polymer flocculant dissolution tank 2 is arranged in communication with the pipe connecting the high-speed stirring tank 7 and the sludge flowmeter 12 via the first polymer flocculant pump 5, and the high-speed stirring is performed.
  • the second polymer flocculant dissolution tank 3 is arranged in communication with the pipe connecting the tank 7 and the normal speed stirring tank 8 via the second polymer flocculant pump 6.
  • sludge A was used as an object to be processed.
  • the measurement method conformed to the sewage test method.
  • a cationic polymer flocculant a (DAA polymer flocculant, molecular weight 9 million, viscosity 300 mPa ⁇ s) was used for both the first and second polymer flocculants.
  • the concentration of the solution of the first and second polymer flocculants was adjusted to 2 g / L.
  • the first polymer flocculant solution and the second polymer flocculant solution are both aqueous solutions obtained by dissolving the polymer flocculant in water. This means the concentration of the molecular flocculant (the same applies to the experiments described later).
  • the experimental procedure is as follows.
  • the first polymer flocculant solution is added to sludge (sludge flow rate 1.4 to 2.9 m 3 / h) by 65% of the total injection amount, and a high speed stirrer (rotation speed 1250 to 2750 rpm, power consumption 0.48 to
  • the mixed sludge was prepared by mixing and stirring the sludge and polymer flocculant solution by 2.43 kW and a stirring portion volume of 0.8 L).
  • 35% of the total injection amount of the second polymer flocculant solution is added to the mixed sludge, and the mixed sludge and polymer flocculant are mixed and stirred with a stirrer set at a rotation speed of 150 rpm for mixing.
  • Sludge was agglomerated to form agglomerated floc.
  • the aggregated floc was dehydrated with a belt press dehydrator, and the moisture content (%) of the obtained dehydrated cake was measured.
  • the moisture content (%) of the dehydrated cake was determined from the mass of water evaporated when the dehydrated cake was evaporated to dryness at 105 to 110 ° C.
  • the measurement method conformed to the sewage test method. (Same for subsequent experiments). The experimental results are shown in Table 1.
  • the formula (1) value R of (power consumption A ⁇ sludge concentration C) / sludge treatment amount B can be reduced to 0.40 to 1.10, preferably 0.50 to 1.00, and even more preferably 0.60 to 0.90, to reduce the moisture content of the dewatered cake, or to coagulate sludge. It was found that a dehydrated cake can be obtained.
  • Example 2 In this experiment, after the first polymer flocculant solution was added to the sludge and the first stirring was performed, the second polymer flocculant solution was added and the second stirring was performed.
  • the power consumption is adjusted by changing the rotation speed when stirring in the first stirring (that is, the stirring speed) as shown in Table 2, The relationship between the value R of the above formula (1) and the moisture content of the dehydrated cake was examined.
  • sludge and a dehydrator different from Experiment 1 were used.
  • sludge B was used as an object to be processed.
  • Sludge B is anaerobic digested sludge.
  • the measurement method conformed to the sewage test method.
  • a cationic polymer flocculant b (DAA polymer flocculant, molecular weight 8 million, viscosity 280 mPa ⁇ s) was used for both the first and second polymer flocculants.
  • the concentration of the solution of the first and second polymer flocculants was adjusted to 2 g / L.
  • the experimental procedure is as follows.
  • the first polymer flocculant solution is added to sludge (sludge flow rate 1.4 m 3 / h) by 65% of the total injection amount, and a high speed stirrer (rotation speed 1000 to 3000 rpm, power consumption 0.33 to 3.07 kW,
  • the sludge and polymer flocculant solution were mixed and stirred by a stirring portion volume of 0.8 L to prepare mixed sludge.
  • 35% of the total injection amount of the second polymer flocculant solution is added to the mixed sludge, and the mixed sludge and polymer flocculant are mixed and stirred with a stirrer set at a rotation speed of 50 rpm for mixing.
  • Sludge was agglomerated to form agglomerated floc.
  • the aggregated floc was dehydrated with a screw press dehydrator, and the moisture content (%) of the obtained dehydrated cake was measured.
  • Table 2 The experimental results are shown in Table 2.
  • the formula (1) value R of (power consumption A ⁇ sludge concentration C) / sludge treatment amount B is 0.24. And 2.20, the water content of the dehydrated cake was not preferable. Considering these results together with the results of the tests conducted by the inventors so far, the value R in the formula (1) is 0.40 to 1.10, preferably 0.50 to 1.00, and even more preferably. It was found that by adjusting to 0.60 to 0.90, the water content of the dehydrated cake can be reduced, or sludge can be aggregated to obtain a dehydrated cake.
  • Example 3 In this experiment, the first polymer flocculant solution was injected into the sludge and the first stirring was performed, and then the second polymer flocculant solution was injected and the second stirring was performed.
  • the power consumption is adjusted by changing the number of high-speed stirrers used when stirring in the first stirring, and the above formula (1 ) Value R and the moisture content of the dehydrated cake were examined.
  • sludge B was used as an object to be processed.
  • Sludge B is anaerobic digested sludge.
  • the measurement method conformed to the sewage test method.
  • the cationic polymer flocculant b (DAA polymer flocculant, molecular weight 8 million, viscosity 280 mPa ⁇ s) was used for both the first and second polymer flocculants.
  • the concentration of the solution of the first and second polymer flocculants was adjusted to 2 g / L.
  • the experimental procedure is as follows.
  • the first polymer flocculant solution is injected into sludge (sludge flow rate 1.4m 3 / h) at 65% of the total injection amount, and the sludge and polymer flocculant solution are mixed and stirred with a high-speed stirrer.
  • sludge sludge flow rate 1.4m 3 / h
  • the high speed stirrers were connected in series.
  • the rotational speed of the high-speed stirrer is 1000 rpm
  • the power consumption is 0.33 kW
  • the stirring unit volume is 0.8 L.
  • the relationship between the power consumption A, the sludge treatment amount B, and the sludge concentration C when stirring in the first stirring is as follows: (Power consumption A ⁇ sludge concentration C) / Sludge treatment amount B (1)
  • the value R is 0.40. Within the above range, the moisture content of the dehydrated cake could be reduced. From these facts, it was found that by adjusting the formula (1) value R in the range of 0.40 or more, the moisture content of the dehydrated cake can be reduced, or sludge can be aggregated to obtain a dehydrated cake.
  • Example 4 In this experiment, unlike Experiments 1 to 3, the treatment conditions were examined when (sludge treatment amount B / sludge concentration C) was remarkably large, that is, 3.5 or more. That is, in the case where (sludge treatment amount B / sludge concentration C) is 3.5 or more, the first polymer flocculant solution is poured into the sludge and the first stirring is performed, and then the second polymer agglomeration is performed.
  • sludge C was used as an object to be treated.
  • Sludge C is anaerobic digested sludge.
  • the measurement method conformed to the sewage test method.
  • the cationic polymer flocculant b (DAA polymer flocculant, molecular weight 8 million, viscosity 280 mPa ⁇ s) was used for both the first and second polymer flocculants.
  • the concentration of the solution of the first and second polymer flocculants was adjusted to 2 g / L.
  • the experimental procedure is as follows.
  • the first polymer flocculant solution is injected into sludge (sludge flow rate 3.5-25.0 m 3 / h) at 65% of the total injection amount, and the sludge and polymer flocculant solution are mixed and stirred with a high-speed stirrer. And mixed sludge was prepared.
  • the rotational speed of the high-speed stirrer is 2200 to 3700 rpm, the power consumption is 1.4 to 4.8 kW, and the volume of the stirring unit is 0.8 L.
  • Example 5 In this experiment, the first polymer flocculant solution was injected into the sludge and the first stirring was performed, and then the second polymer flocculant solution was injected and the second stirring was performed.
  • the volume of the stirring section in the high-speed stirrer when stirring in the first stirring hereinafter referred to as “stirring section volume”.
  • the power consumption per stirring unit volume was adjusted, and the relationship between the power consumption per stirring unit volume and the moisture content of the dehydrated cake was examined.
  • sludge C was used as an object to be treated.
  • Sludge C is anaerobic digested sludge.
  • the measurement method conformed to the sewage test method.
  • the cationic polymer flocculant b (DAA polymer flocculant, molecular weight 8 million, viscosity 280 mPa ⁇ s) was used for both the first and second polymer flocculants.
  • the concentration of the solution of the first and second polymer flocculants was adjusted to 2 g / L.
  • the experimental procedure is as follows.
  • the first polymer flocculant solution is injected into sludge (sludge flow rate 2.0 m 3 / h) at 65% of the total injection amount, and the sludge and polymer flocculant solution are mixed and stirred with a high-speed stirrer, and mixed sludge is mixed.
  • the rotational speed of the high-speed stirrer is 2000 rpm
  • the power consumption is 1.11 kW
  • the volume of the stirring unit is 0.8, 1.6 L.
  • the value obtained by dividing the power consumption during stirring in the first stirring by the volume of the stirring portion (power consumption / volume of the stirring portion), that is, stirring
  • the power consumption (kW) per unit volume (L) to be 1.0 (kW / L) or more
  • the moisture content of the dehydrated cake can be further reduced, or sludge can be aggregated and dehydrated. It turns out that a cake can be obtained.
  • Reference Experiment 1 In Reference Experiment 1, after the first polymer flocculant solution was added to the sludge and the first stirring was performed, the second polymer flocculant solution was added and the second stirring was performed. In the process of dewatering sludge with a belt press dehydrator to obtain a dehydrated cake, the agitation speed in the first agitation was changed to examine the relationship with the moisture content of the dehydrated cake.
  • sludges O, P and Q Three types of sludge (O, P, Q) were used in the experiment. Both are anaerobic digested sludge. All were collected from different wastewater treatment facilities.
  • the TS of the sludges O, P and Q are 12.0, 26.2 and 34.9 g / L, respectively.
  • TS is an evaporation residue, and is a concentration of a substance remaining when sludge is evaporated to dryness at 105 to 110 ° C.
  • the measurement method conformed to the sewage test method.
  • a cationic polymer flocculant o (DAM polymer flocculant, molecular weight 3 million, viscosity 114 mPa ⁇ s) was used for both the first and second polymer flocculants.
  • the cationic polymer flocculant g was used for both the first and second polymer flocculants.
  • a cationic polymer flocculant h (amidine polymer flocculant, molecular weight 3 million, viscosity 34 mPa ⁇ s) was used for both the first and second polymer flocculants.
  • the first polymer flocculant solution and the second polymer flocculant solution are both aqueous solutions obtained by dissolving the polymer flocculant in water. It means the concentration of the molecular flocculant (the same applies to the reference experiment described later).
  • the experimental procedure is as follows. A predetermined amount of the first polymer flocculant solution (concentration: 10 g / L) was added to 250 mL of sludge, and the sludge and polymer flocculant solution were mixed and stirred for 10 seconds with a high-speed stirrer to prepare mixed sludge. Next, a predetermined amount of a second polymer flocculant solution (concentration: 10 g / L) is added to the mixed sludge, and the mixed sludge and polymer flocculant are mixed and stirred for 2 minutes with a stirrer with a stirring speed of 150 rpm. Aggregated to form aggregated floc. Finally, the aggregated floc was dehydrated with a belt press dehydrator, and the moisture content (%) of the obtained dehydrated cake was measured.
  • the moisture content (%) of the dehydrated cake was determined from the mass of water evaporated when the dehydrated cake was evaporated to dryness at 105 to 110 ° C.
  • the measurement method conformed to the sewage test method. (The same applies to the following reference experiments).
  • Table 6 shows the experimental results. In the table, “-” indicates that there is no data.
  • the moisture content of the cake could be reduced when the stirring speed of the high-speed stirrer was about 1000 rpm or more.
  • sludge Q sludge could be aggregated at a stirring speed of about 3000 rpm or more, and a dehydrated cake could be obtained. From these facts, the moisture content of the cake can be reduced or the sludge can be agglomerated by adjusting the stirring speed of high-speed stirring to preferably 1000 rpm or more, more preferably 2000 rpm or more, and even more preferably 3000 rpm or more. It turns out that can be obtained.
  • sludges O and R Three types of sludge (O, R, S) were used in the experiment. Both are anaerobic digested sludge. Sludges O and R were collected from the same wastewater treatment facility, but with different sludge concentrations. Sludge S was collected from a wastewater treatment facility different from sludges O and R. The TS of sludges O, R, and S are 12.0, 12.2, and 37.1 g / L, respectively. In the experiments of sludges O and R, a cationic polymer flocculant o (DAM polymer flocculant, molecular weight 3 million, viscosity 114 mPa ⁇ s) was used for both the first and second polymer flocculants.
  • DAM polymer flocculant a cationic polymer flocculant o
  • a cationic polymer flocculant h (amidine polymer flocculant, molecular weight 3 million, viscosity 34 mPa ⁇ s) was used for both the first and second polymer flocculants.
  • the first and second polymer flocculant solutions were prepared to the same concentration. For example, when the first polymer flocculant solution was prepared at 2 g / L, the second polymer flocculant solution was also prepared at 2 g / L. When the first polymer flocculant solution was prepared at 20 g / L, the second polymer flocculant solution was also prepared at 20 g / L.
  • the experimental procedure is as follows. A predetermined amount of the first polymer flocculant solution (concentration 2 to 20 g / L) is added to 250 mL of sludge, and the sludge and polymer flocculant solution are mixed and stirred for 10 seconds with a high-speed stirrer with a stirring speed of 10,000 to 11000 rpm. A mixed sludge was prepared. Next, a predetermined amount of a second polymer flocculant solution (concentration 2 to 20 g / L) is added to the mixed sludge, and the mixed sludge and polymer flocculant are mixed and stirred for 2 minutes with a stirrer with a stirring speed of 150 rpm.
  • the moisture content of the cake was reduced when the first polymer flocculant concentration was 3 g / L or more, and the moisture content of the cake was reduced most at about 10 g / L.
  • the cake moisture content could be reduced when the first polymer flocculant concentration was 3 g / L or more, and the cake moisture content could be reduced most at 3 g / L and 5 g / L.
  • the sludge S the moisture content of the cake was reduced when the first polymer flocculant concentration was 3 g / L or more, and the moisture content of the cake could be reduced most at about 10 g / L. From these facts, the concentration of the first polymer flocculant solution is preferably 3 g / L or more, more preferably 5 g / L or more, and even more preferably 10 g / L or more. It was found that it can be reduced.
  • Reference Experiment 3 In Reference Experiment 3, after the first polymer flocculant solution was added to the sludge and the first stirring was performed, the second polymer flocculant solution was added and the second stirring was performed. In the process of dewatering sludge with a belt press dehydrator to obtain a dehydrated cake, the type of the first polymer flocculant was changed to examine the relationship between the moisture content of the dehydrated cake and the SS recovery rate.
  • Sludge T was used for the experiment.
  • Sludge T is anaerobic digested sludge.
  • the TS of the sludge T is 20.9 g / L.
  • polymer flocculant polymer flocculants (o, p, q, r, s, t) having different molecular weights were used.
  • Polymer flocculants o, p, q, r, and t are cationic polymer flocculants.
  • polymer flocculants o and p are DAM polymer flocculants
  • polymer flocculants q, r, and t are DAA. Based polymer flocculants.
  • the polymer flocculant s is an amphoteric polymer flocculant.
  • the molecular weights (viscosity mPa ⁇ s) of the polymer flocculants o, p, q, r, s, and t are 3 million (114 mPa ⁇ s), 4 million (143 mPa ⁇ s), 5 million (147 mPa ⁇ s), respectively. 6 million (225 mPa ⁇ s), 7 million (238 mPa ⁇ s), and 8 million (280 mPa ⁇ s).
  • the molecular weight described here is an average molecular weight determined by a viscosity method. The viscosity is a value measured by dissolving the polymer flocculant in water at 2 g / L and using a B-type viscometer at 25 ° C. and 60 rpm.
  • the experimental procedure is as follows. 31 mL of the first polymer flocculant solution (concentration 2 g / L) is added to 250 mL of sludge, and the sludge and polymer flocculant solution are mixed and stirred for 10 seconds with a high-speed stirrer with a stirring speed of 5000 rpm to prepare mixed sludge. did. Next, 9 mL of the second polymer flocculant solution (concentration 2 g / L) is added to the mixed sludge, and the mixed sludge and the polymer flocculant are mixed and stirred for 5 minutes with a stirrer with a stirring speed of 200 rpm, thereby aggregating the mixed sludge.
  • the ratio of the SS recovery rate indicates a ratio when the SS recovery rate when the polymer flocculant t is used is 100.
  • the ratio of SS recovery was 97 or more when the molecular weight was 5 million or more (polymer flocculants q, r, s, t), but 81 to 87 when the molecular weight was 4 million or less (polymer flocculants o and p). Met.
  • the moisture content of the cake was in the range of 82 to 83%. From these results, it was found that the SS recovery rate can be increased by using a polymer flocculant having a molecular weight of preferably 4.5 million or more, more preferably 5 million or more.
  • Reference Experiment 4 In Reference Experiment 4, after the first polymer flocculant solution was added to the sludge and the first stirring was performed, the second polymer flocculant solution was added and the second stirring was performed. In the process of dewatering sludge with a belt press dehydrator to obtain a dehydrated cake, the injection amount of the first polymer flocculant was changed to examine the relationship with the SS recovery rate.
  • Sludge T was used for the experiment.
  • Sludge T is anaerobic digested sludge.
  • the TS of the sludge T is 20.9 g / L.
  • polymer flocculant polymer flocculants (q, r, s, t) having different molecular weights were used.
  • the polymer flocculants q, r, and t are cationic polymer flocculants, and the polymer flocculant s is an amphoteric polymer flocculant.
  • the molecular weights (viscosity mPa ⁇ s) of the polymer flocculants q, r, s, and t are 5 million (147 mPa ⁇ s), 6 million (225 mPa ⁇ s), 7 million (238 mPa ⁇ s), and 8 million (280 mPa, respectively). S).
  • the molecular weight described here is an average molecular weight determined by a viscosity method.
  • the viscosity is a value measured by dissolving the polymer flocculant in water at 2 g / L and using a B-type viscometer at 25 ° C. and 60 rpm. In the experiment, the same kind of both the first and second polymer flocculants were used, and the solutions of the first and second polymer flocculants were prepared at the same concentration.
  • the experimental procedure is as follows. A predetermined amount of the first polymer flocculant solution (concentration 2 g / L) is added to 250 mL of sludge, and the sludge and polymer flocculant solution are mixed and stirred for 10 seconds with a high-speed stirrer with a stirring speed of 5000 rpm. Prepared. Next, a predetermined amount of a second polymer flocculant solution (concentration 2 g / L) is added to the mixed sludge, and the mixed sludge and the polymer flocculant are mixed and stirred for 5 minutes with a stirrer with a stirring speed of 200 rpm. Aggregated to form aggregated floc. Finally, the aggregated floc was dehydrated with a belt press dehydrator to obtain a dehydrated cake, and the SS recovery rate was measured.
  • the total injection amount of the first and second polymer flocculant solutions was 40 mL, and the first polymer flocculant solution was added in a range of 2.5 to 37.5 mL.
  • the experimental results are shown in FIG.
  • FIG. 6 is a graph showing the relationship between the injection amount of the polymer flocculant added during high-speed stirring and the ratio of the average SS recovery rate when the polymer flocculants q, r, s, and t are used.
  • the ratio of the average SS recovery rate indicates the ratio when the average SS recovery rate is 100 when the injection amount of the first polymer flocculant is 59%.
  • SS was adjusted by adjusting the injection amount of the polymer flocculant added at the time of high-speed stirring to preferably 45 to 95%, more preferably 50 to 95%, and still more preferably 55 to 90% of the total injection amount. It has been found that the recovery rate can be increased.
  • Reference Experiment 5 In Reference Experiment 5, after the first polymer flocculant solution was added to the sludge and the first stirring was performed, the second polymer flocculant solution was added and the second stirring was performed. In the process of dewatering sludge with a belt press dehydrator to obtain a dehydrated cake, the total injection rate of the first and second polymer flocculants was changed to examine the relationship with the moisture content of the dehydrated cake.
  • Sludge Q was used for the experiment.
  • Sludge Q is anaerobic digested sludge.
  • the TS of sludge Q is 34.9 g / L.
  • a cationic polymer flocculant h (amidine polymer flocculant, molecular weight 3 million, viscosity 34 mPa ⁇ s) was used for both the first and second polymer flocculants.
  • the cationic polymer flocculant h was prepared at 10 g / L.
  • the experimental procedure is as follows. A predetermined amount of the first polymer flocculant solution was added to 250 mL of sludge, and the sludge and polymer flocculant solution were mixed and stirred for 10 seconds with a high-speed stirrer with a stirring speed of 11000 rpm to prepare mixed sludge. Next, 5 mL of the second polymer flocculant solution is added to the mixed sludge, and the mixed sludge and the polymer flocculant are mixed and stirred for 2 minutes with a stirrer with a stirring speed of 150 rpm to aggregate the mixed sludge and form a floc floc I let you.
  • the aggregated floc was dehydrated with a belt press dehydrator, and the moisture content (%) of the obtained dehydrated cake was measured.
  • the injection amount of the second polymer flocculant solution was constant (5 mL), and the injection amount of the first polymer flocculant was changed in the range of 12 to 19 mL in accordance with the total injection rate.
  • sludge was agglomerated by stirring at a normal speed and a solution of a polymer flocculant of 2 g / L, and the agglomerated sludge was dehydrated by a belt press dehydrator.
  • the experimental procedure of this reference comparative example is as follows. Add a predetermined amount of polymer flocculant solution (concentration 2 g / L) to 250 mL of sludge, mix and stir the sludge and polymer flocculant for 3 minutes with a stirrer with a stirring speed of 150 rpm, and coagulate the sludge to form an aggregate floc I let you.
  • FIG. 7 shows the relationship between the polymer flocculant injection rate and the moisture content of the dehydrated cake. From this result, it was found that the water content of the dehydrated cake was 2 to 3 when the high-speed stirring and the 10 g / L polymer flocculant solution were used than when the normal speed stirring and the 2 g / L polymer flocculant solution were used. It was found that the point could be reduced. Also, the use of high-speed stirring and 10 g / L polymer flocculant solution has a higher polymer flocculant injection rate of 2 to 3 than the use of normal speed stirring and 2 g / L polymer flocculant solution. It was found that it can be reduced by about 10%.
  • Reference Experiment 6 In Reference Experiment 6, after sludge was diluted with diluting water and sludge dilution was performed, the first polymer flocculant solution was added to the sludge and the first stirring was performed, and the second polymer flocculant solution In the process of dehydrating the obtained agglomerated sludge with a screw press dehydrator to obtain a dehydrated cake, the water content of the dehydrated cake could be reduced by performing sludge dilution. .
  • Sludge H was used for the experiment.
  • Sludge H is anaerobic digested sludge.
  • the TS of sludge H during the experiment period was 42.5 to 43.5 g / L.
  • the concentration of the soluble component of the sludge H was extremely high, the electrical conductivity of the sludge H during the test period was 19.9 to 21.1 mS / cm, and the M alkalinity was 7600 to 9000 mg-CaCO 3 / L.
  • Cationic polymer flocculant h (amidine polymer flocculant, molecular weight 3 million, viscosity 34 mPa ⁇ s) was used for both the first and second polymer flocculants.
  • the cationic polymer flocculant h was adjusted to 2 g / L or 5 g / L.
  • Industrial water was used to dissolve the polymer flocculant. Industrial water was used as dilution water.
  • the experimental procedure was performed continuously as follows. Diluted water (diluted water flow rate 1.5 m 3 / h) was added to sludge (sludge flow rate 3.0 m 3 / h) to prepare diluted sludge (1.5 times dilution). Add 70% of the total amount of the first polymer flocculant to the diluted sludge and mix and stir the diluted sludge and polymer flocculant solution with a high-speed stirrer (stirring unit volume 0.8L) with a stirring speed of 3000rpm. And mixed sludge was prepared.
  • the injection rate of the polymer flocculant and the moisture content of the dehydrated cake could be reduced by performing the dilution step. Even when the concentration of the polymer flocculant solution was 5 g / L, the injection rate of the polymer flocculant and the water content of the dehydrated cake could be reduced by performing the dilution step. From these facts, it was found that the introduction rate of the sludge can reduce the injection rate of the polymer flocculant and the moisture content of the dewatered cake.
  • Reference Experiments 1 to 5 are batch, whereas the experiment in this Reference Experiment (Reference Experiment 6) was performed continuously. In addition, when the same experiment as Reference Experiments 1 to 5 was performed continuously, no difference was found between the results of the batch experiment and the continuous experiment.

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JP2016101540A (ja) * 2014-11-27 2016-06-02 水ｉｎｇ株式会社 汚泥凝集方法及び装置、及び汚泥処理装置
JP2017042712A (ja) * 2015-08-26 2017-03-02 水ｉｎｇ株式会社 汚泥の凝集方法及び装置
JPWO2016157646A1 (ja) * 2015-03-31 2018-01-25 株式会社クボタ 急速撹拌機の制御方法および急速撹拌機
CN114940575A (zh) * 2022-05-27 2022-08-26 国投信开水环境投资有限公司 一种用于调理污泥的装置及方法

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JPWO2016157646A1 (ja) * 2015-03-31 2018-01-25 株式会社クボタ 急速撹拌機の制御方法および急速撹拌機
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CN114940575A (zh) * 2022-05-27 2022-08-26 国投信开水环境投资有限公司 一种用于调理污泥的装置及方法

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