JP2018153730A - Water purification sludge treatment agent, water purification sludge treatment method and water purification sludge treatment equipment - Google Patents

Abstract

An object of the present invention is to improve sludge concentration and sludge releasability, and to suppress clogging of filtration when separated water generated by sludge treatment is reused for water purification treatment. The water purification sludge treatment agent of the present invention contains a polycarboxylic acid-based polymer, has a 0.1% by mass salt viscosity of 2 to 5 mPa · s when dissolved in a 1 mol / L sodium chloride solution, and 25 g When dissolved in / L sodium chloride solution, the 0.1 mass% solution viscosity is 6 mPa · s or less, and the anion equivalent is 4.5 meq / g or more. When such a purified water sludge treatment agent is used for the purified water sludge treatment, the concentration of the purified water sludge 7 is improved, and the dewaterability of the concentrated sludge 9 and the peelability of the dewatered cake 11 are also improved. In addition, when the separated water 10 and the supernatant waters 5 and 8 generated by the sludge treatment are reprocessed in the water purification process, the filtration blockage of the filtration basin 25 is also suppressed. [Selection] Figure 1

Description

  The present invention relates to a purified water sludge treatment agent, a sludge treatment method and a sludge treatment apparatus using the same, and more specifically, a purified water sludge treatment agent, a sludge treatment method and a sludge treatment with improved sludge concentration and dewatering efficiency. It relates to the device.

  Conventionally, in water purification treatment, an inorganic flocculant such as a sulfate band or polyaluminum chloride (PAC) is injected into water to be treated containing suspended solids (hereinafter also referred to as “raw water”), and suspended solids are taken in. Suspended substances were removed by forming agglomerated floc and allowing the agglomerated floc to settle and separate. The suspended and separated suspended matter was extracted from the sedimentation tank as sludge (purified water sludge), and usually concentrated in a concentration tank and then disposed of by sun drying or mechanical dehydration.

  By the way, when lake water or dam water is used as raw water, algae such as blue-green algae are generated at high temperatures, which may cause poor aggregation. The coagulation flocs at the time of coagulation failure also have poor sedimentation properties, and sludge generated is not sufficiently settled in the sedimentation tank, so that the generated sludge has a low concentration. Therefore, it cannot be concentrated to a satisfactory concentration even in a concentration tank, and it must be mechanically dehydrated with a low concentration. In particular, when the dehydrator is a filter press, there is a problem that the driving time is long, the dehydrated cake has a high moisture content, and the delamination of the dehydrated cake from the filter is deteriorated. There was also a problem that it took time.

JP 7-308700 A JP-A-9-225208 JP-A-55-84505 Japanese Patent Publication No.34-612

  In the above-described conventional method for treating purified water sludge, in order to improve the concentration of purified water sludge, it has been studied to use a polyacrylamide-based anionic polymer flocculant in a concentration tank. According to this method, the concentration property of the sludge is certainly improved and a high concentration sludge can be obtained. However, the coagulated floc constituting the concentrated sludge becomes highly viscous, and when this concentrated sludge is dehydrated by a filter press, the peelability of the dewatered cake from the filter may be deteriorated.

  Also, in the water purification treatment, all the desorbed water separated from the dewatered cake in the sludge dewatering process is returned to the landing well and reused, so the residual polymer in the dewatered water is circulated without being discharged out of the system. Return to the water purification process again. Therefore, this residual polymer may affect the increase in filtration resistance (filtration resistance) of the filtration process in the water purification treatment.

  In Patent Document 1, sodium polyacrylate is added to the concentrated sludge generated from the water purification process. However, since the concentrated sludge is generally high in concentration, it is difficult to uniformly mix with the flocculant. An excess flocculant of the reaction may remain. Since the flocculant has adhesiveness, particularly when it is dehydrated with a filter press, the peelability of the dewatered cake from the filter cloth may be deteriorated.

  The present invention has been made in view of the above problems, and its purpose is to remove a dewatered cake when dewatering or drying concentrated sludge at a high concentration without adversely affecting the water purification process, particularly the filtration process. An object of the present invention is to provide a treatment agent for purified water sludge, a treatment method for purified water sludge, and a treatment apparatus for the same, which improve dryness and generate dry sludge having an appropriate water content.

  In order to solve the above problems, the present invention can be configured as follows.

  (1) The water purification sludge treatment agent of the present invention is not particularly limited as long as it contains a polycarboxylic acid polymer, but the whole of the water purification sludge treatment agent satisfies the following characteristics (a) to (c). (A) 0.1 mass% salt viscosity when dissolved in a 1 mol / L sodium chloride solution is 2 mPa · s to 5 mPa · s, (b) 0.1 mass% solution when dissolved in a 25 g / L sodium chloride solution The viscosity is 6 mPa · s or less, and (c) the anion equivalent is 4.5 meq / g or more.

  (2) The polycarboxylic acid-based polymer is not particularly limited, but preferably includes poly (meth) acrylic acid or a salt thereof, more preferably includes poly (meth) acrylic acid or a salt thereof as a main component, and particularly preferably. What consists of any one or both of poly (meth) acrylic acid and poly (meth) acrylate is used.

  (3) The present invention is not limited to the purified water sludge treatment agent, but also relates to a purified water sludge treatment method having a purified water treatment step, a concentration step, a dehydration step, and a supply step, After coagulating and precipitating the treated water, it is filtered to obtain purified water, and the concentration step concentrates the purified water sludge containing at least one of the coagulated sediment sludge separated from the water purification treatment step and the filtration washing wastewater discharged from the apparatus used for filtration. Thus, the concentrated sludge is obtained, the dewatering step dehydrates the concentrated sludge, and the supply step is a step of adding the above-described purified water sludge treatment agent to one or both of the purified water sludge and the concentrated sludge.

  (4) The above steps are not particularly limited, but the dehydration step is preferably mechanical dehydration using a filter press.

  (5) The present invention further relates to a purified water sludge treatment apparatus, and the purified water sludge treatment apparatus has a purified water treatment means, a concentration means, a dehydration means, and a supply means, and the purified water treatment means is covered. The treated water is coagulated and precipitated, filtered to obtain purified water, and the concentration means concentrates the purified water sludge containing at least one of the aggregated sludge separated by the purified water treatment means and the filtration washing wastewater discharged from the filtration device, The dewatering means dehydrates the concentrated sludge, and the supplying means adds the above-described purified water sludge treatment agent to one or both of the purified water sludge and the concentrated sludge.

  (6) Although each said means is not specifically limited, It is preferable to use a filter press type | mold dehydrating means for a dehydrating means.

  According to the present invention, the concentration of purified water sludge is improved, and high-concentration sludge can be obtained. In addition, the peelability of the concentrated sludge is improved, and contamination of the apparatus and the filter is prevented during mechanical dehydration, and a dehydrated cake having an appropriate water content can be obtained. Furthermore, even if the separated water generated by the concentration and dehydration of sludge is returned to the landing well, the filtration failure in the water purification process is suppressed.

It is a flowchart explaining the purified water sludge process by this invention. It is a schematic diagram which shows an example of the purified water sludge processing apparatus of this invention.

  Hereinafter, the present invention will be specifically described, but the present invention is not limited to a specific example.

  FIG. 1 is a flow showing an example of the purified water sludge treatment, and the treated water becomes treated water (purified water) through purified water treatment such as aggregation, precipitation, and filtration. On the other hand, the sludge generated in the water purification process becomes a dewatered cake through sludge treatment such as concentration and dehydration, and the supernatant and separated water separated by solid and liquid are reprocessed in the water purification process. The purified water sludge treatment agent of the present invention is particularly suitable for the sludge treatment as described above.

  First, a specific example is demonstrated about the chemical | medical agent used by the said water purification sludge process, ie, the flocculant used for floc production | generation in the process of water purification treatment, and the water purification sludge treatment agent of this invention used by sludge treatment.

[Flocting flocculant]
The flocculant is not particularly limited as long as it is suitable for generating flocs, but an inorganic flocculant is generally used.

  An inorganic flocculant is not specifically limited, The inorganic flocculant normally used for a water purification process can be used. Specifically, one or both of an iron-based flocculant and an aluminum-based flocculant can be used, and more specifically, aluminum sulfate, polyaluminum chloride (PAC), aluminum chloride, polyferric sulfate. Any one or more selected from the group consisting of (polyiron), ferric chloride, and mixtures thereof can be used.

  For the purpose of promoting floc growth, one or more kinds of auxiliary agents selected from a coagulant aid, a pH adjuster, a buffering agent, a polymer coagulant and a sedimentation promoter are used together with the inorganic coagulant or the inorganic coagulant. It may be added separately. The polymer flocculant for floc growth is preferably added to the water to be treated after the inorganic flocculant is added and rapidly stirred.

  The polymer flocculant is not particularly limited, but poly (meth) acrylic acid, poly (meth) acrylamide, poly (meth) acrylamide copolymer, poly (meth) acrylate, poly (meth) acrylic Although various things, such as an ester copolymer system, can be used, Preferably, the same thing as the following purified water sludge processing agent is used.

[Purified water sludge treatment agent]
The purified water sludge treatment agent used for sludge concentration and sludge dehydration contains a polycarboxylic acid polymer, and preferably contains a polycarboxylic acid polymer as a main component (50% by mass). The content of the acid polymer is preferably 70% by mass or more, more preferably 90% by mass or more, and a water purification sludge treatment agent substantially composed of a polycarboxylic acid polymer is most preferable.

  As the polycarboxylic acid polymer, either a natural product or a synthetic product can be used. For example, in the case of a synthetic product, in addition to a polymer formed using at least one of a carboxylic acid and a carboxylic acid salt, a polymer is produced with a monomer other than carboxylic acid or a salt thereof, and then a substituent of the polymer. Also included are those obtained by carboxylation of at least a part of these by chemical modification such as hydrolysis.

  That is, the polycarboxylic acid polymer is not particularly limited as long as it is a polymer having at least one of carboxylic acid and carboxylate as a structural unit, and may be a homopolymer or a copolymer. Hereinafter, a carboxylic acid or a salt thereof is abbreviated as a carboxylic acid (salt), and the other compounds are also abbreviated in the same manner when a salt can be used.

  The carboxylic acid (salt) used as a raw material for the polycarboxylic acid polymer is not particularly limited, and one or both of an unsaturated carboxylic acid (salt) and a saturated carboxylic acid (salt) can be used. ) Use one or more selected from unsaturated carboxylic acids (salts) such as acrylic acid (salt), maleic acid (salt), itaconic acid (salt), crotonic acid (salt), vinylbenzoic acid (salt), etc. Can do.

  The most preferred carboxylic acid (salt) is selected from (meth) acrylic acid (salt), ie acrylic acid and its salts, methacrylic acid and its salts. As the salt, ammonium salts can be used in addition to alkali metal salts such as sodium and potassium, but alkali metal salts, particularly sodium is preferable.

  When a polycarboxylic acid (co) polymer is produced by copolymerizing a carboxylic acid (salt) and a comonomer other than the carboxylic acid (salt), the type of comonomer is not particularly limited. For example, vinyl sulfonic acid (salt) ) Or more anionic monomers: (meth) acrylamide, (meth) acrylate (salt) or one or more nonionic monomers selected from derivatives thereof: nitrogen-containing (meth) acrylate (salt), amino One or more kinds of cationic monomers selected from a group-containing ethylenically unsaturated compound (salt) and an amine imide group-containing compound (salt) can be used.

  The above comonomer can be used in combination of one or more, and the amount thereof is not particularly limited. However, as will be described later, in order to increase the anion equivalent of the entire treating agent, the amount of the cationic monomer used should be less than 5 mol% of the entire monomer raw material, and preferably no cationic monomer is used. Moreover, also when using a nonionic monomer, the usage-amount is restrict | limited so that an anion equivalent may become the optimal value mentioned later. Furthermore, only an anionic monomer can be used.

  Among nonionic monomers, those that are toxic, such as (meth) acrylamide, are preferably used in an amount of 10 mol% or less, more preferably 5 mol% or less of the entire monomer raw material. Moreover, even if a carboxylic acid polymer is produced without using (meth) acrylamide, the treatment agent of the present invention has little influence on the sludge concentration capacity. Note that (meth) acrylamide is a concept including both acrylamide and methacrylamide.

  In the case where a natural product (including an extract and a chemically modified product) is used separately from or together with the synthetic product obtained by polymerizing the monomer as described above, the kind thereof is not particularly limited. As the polycarboxylic acid polymer derived from a natural product, for example, one or more kinds can be selected from alginic acid (salt), carboxymethylcellulose (salt), polyglutamic acid (salt), pectin (salt), and the like.

  As described above, as the polycarboxylic acid polymer, one or more various types such as a synthetic product, a natural product, a copolymer, a homopolymer, and a chemically modified product can be selected and used. A polycarboxylic acid polymer that can also be used as a food additive, specifically, from the group consisting of poly (meth) acrylic acid (salt), alginic acid (salt), carboxymethylcellulose (salt), polyglutamic acid (salt) One or more are selected.

  Among these, poly (meth) acrylic acid (salt) having high sludge concentration performance is most preferable, and a combination of poly (meth) acrylic acid (salt) and one or more other suitable polycarboxylic acid polymers is used. However, the proportion of poly (meth) acrylic acid (salt) in the entire polycarboxylic acid copolymer is preferably 50% by mass or more, more preferably 75% by mass or more, and still more preferably 80%. It is also possible to use only poly (meth) acrylic acid (salt) as a polycarboxylic acid-based copolymer.

  Poly (meth) acrylic acid (salt) is not particularly limited. For example, polyacrylic acid, sodium polyacrylate, potassium polyacrylate, ammonium polyacrylate, polymethacrylic acid, sodium polymethacrylate, polypotassium methacrylate, Any one or more selected from the group consisting of polyammonium methacrylate can be used, and sodium polyacrylate is particularly preferred.

  The purified water sludge treatment agent component other than the polycarboxylic acid-based polymer as described above is not particularly limited, and one or more other polymer flocculants and one or more additives can be added. Specific examples of other polymer flocculants include poly (meth) acrylamide, amine condensation type, DADMAC (polydiallyldimethylammonium chloride), melamic acid colloid, sulfonic acid type, poly (meth) acrylic ester type, dicyandiamide type and the like. is there. However, more preferably, no polymer flocculant other than the polycarboxylic acid polymer is used.

  As described above, if the water purification sludge treatment agent of the present invention contains a polycarboxylic acid polymer as an essential component, when it consists of only one or two or more polycarboxylic acid polymers, Although cases including substances other than coalescence (other polymer flocculants, additives, etc.) are also conceivable, in all cases, the 0.1 wt% salt viscosity is 2 mPa · s to 5 mPa in the whole purified water sludge treatment agent. · S, 0.1% by mass Solution viscosity of 6 mPa · s or less, and anion equivalent of 4.5 meq / g or more, types and amounts of polycarboxylic acid polymers, and polycarboxylic acid polymers Adjust the type and amount of substances other than

  Here, the 0.1% by mass salt viscosity is a sodium chloride aqueous solution (1 mol / L) in which 1 mol of sodium chloride (about 58.44 g) is dissolved in 1 L of water, and the solid content concentration of the purified water sludge treatment agent. A sample was prepared by dissolving to 0.1% by mass, and this sample was measured with a B-type viscometer at 25 ° C. The unit is mPa · s.

  The 0.1 mass% salt viscosity is an indicator of the cohesiveness of the aggregated flocs. When the 0.1 mass% salt viscosity is less than 2 mPa · s, the aggregated flocs are not so large and improvement in sedimentation cannot be expected. . On the other hand, when the 0.1% by mass salt viscosity exceeds 5 mPa · s, it causes a peeling failure during dehydration and an increase in the moisture content of the cake.

  The anion equivalent is a value that can be determined by the following measurement method, and the unit is meq / g. Prepare an aqueous solution (1 g / L) of 1 g (solid content) of purified water sludge treatment agent in 1 L of water, add 5 ml of N / 200 methylglycol chitosan solution, add 2 to 3 drops of toluidine blue indicator after stirring. Titration with PVSK solution (N / 400 polyvinyl potassium sulfate solution), discoloration, and the time of holding for 10 seconds or more is defined as the end point. A blank test is performed without adding a sample by the same operation, and an anion equivalent Av is calculated by the following formula.

Anion equivalent (Av) [meq / g] =
(Blank titration [ml]-Sample titration [ml]) x 1/2 x PVSK solution titer

  The anionic polymer is negatively colloidally charged, and a method of expressing it as a colloidal charge amount with a minus sign added to the colloid equivalent value is also used. Expressed as equivalents. That is, the larger the anion equivalent, the higher the (strong) anion, and the smaller the anion equivalent, the closer to the low (weak) anion, that is, nonionicity (eg, anionic equivalent 0 to 0.7 is nonionic).

  The purified water sludge treatment agent of the present invention has an anion equivalent of 4.5 or more, a preferred anion equivalent is 4.5 to 11.0, and a particularly preferred anion equivalent is 9.0 or more. When the anion equivalent value is less than 4.5, a strong floc (for example, coarse agglomerated sludge floc) is not formed, which causes peeling failure during dehydration and an increase in the moisture content of the cake.

  The 0.1 mass% solution viscosity was measured by the same method as the 0.1 mass% salt viscosity except that the amount of sodium chloride was changed from 1 mol to 25 g to adjust the aqueous sodium chloride solution (25 g / L). Viscosity, unit is mPa · s.

  The above-mentioned 0.1 mass% salt viscosity and anion equivalent have been conventionally used for evaluating the coagulation performance of the polymer flocculant, but these indicators are filtration devices (sand filtration ponds) in the water purification process. Was not discussed in relation to the filtration resistance of As a result of intensive studies by the present inventors, the degree of influence on filtration resistance when a polymer flocculant is used is optimally evaluated by a 0.1% by mass solution viscosity measured with 25 g / L of sodium chloride. I found out.

  This 0.1% by mass solution viscosity is an index of filtration resistance of the sand filtration pond when the sludge treatment separated water or supernatant water is returned to the water purification process (eg, landing well) and reprocessed. That is, when the 0.1% by mass solution viscosity of the polymer flocculant (purified water sludge treatment agent) is 6 mPa · s or less, the filtration resistance (filtration resistance) is equal to or less than that when the polymer flocculant is not used. You can rise. On the other hand, if the 0.1 mass% solution viscosity of the purified water sludge treatment agent exceeds 6 mPa · s, the rate of increase in the filter resistance is increased, which causes a filtration failure.

  Thus, in the present invention, by making the 0.1 mass% salt viscosity and anion equivalent of the purified water sludge treatment agent within suitable ranges, the sludge can be dehydrated and concentrated, and the dewatered cake can be removed, and By making the 0.1 mass% solution viscosity of the purified water sludge treatment agent into a suitable range, it is also possible to suppress filtration failure due to detached water and supernatant water.

  Next, a purified water sludge treatment apparatus using the purified water sludge treatment agent and a purified water sludge treatment method using the purified water sludge treatment agent will be specifically described.

[Purified water sludge treatment equipment]
The water purification sludge treatment equipment (purified water sludge treatment equipment) to which the present invention can be applied is not particularly limited, and it is possible to adopt all the normal equipment that has been put to practical use. Specifically, the water purification treatment equipment and the sludge treatment are applicable. For example, a water purification facility having a cross-flow type precipitation facility and a water purification facility having a high-speed coagulation sedimentation facility can be mentioned.

  Either a slurry circulation type or a sludge / blanket type can be applied as the high-speed coagulating sedimentation equipment. In addition, it is possible to apply an ultra-high-speed coagulation sedimentation facility using a sedimentation accelerator having a specific gravity larger than that of a normal coagulation floc such as micro sand. However, in any case, the purified water sludge treatment agent of the present invention is particularly suitable for a purified water sludge treatment apparatus having a filtration device such as a filtration pond.

  Hereinafter, an apparatus having a cross-flow type precipitation facility will be specifically described as an example. FIG. 2 shows an example of the purified water sludge treatment apparatus. The purified water sludge treatment apparatus 15 includes a purified water treatment means 20 for performing the purified water treatment and a concentration means 30 for concentrating the purified water sludge. Alternatively, a filtration device such as a filtration basin 25 is installed separately from the water purification treatment means 20.

  More specifically, the water purification treatment means 20 includes a landing well 21, an agglomeration mixing pond (aggregation mixing tank) 22, a flock formation pond (floc formation tank) 23, a settling basin (precipitation tank) 24, and a filtration pond. 25, the treated water 1 (raw water) taken from the water source is introduced into the landing well 21, and in some cases, the supernatant waters 5 and 8 and the separated water 10 separated in the subsequent treatment, Any one or more of the filtration washing waste water 4 and the coagulated sediment sludge 3 (or coarse flocs before precipitation) are also introduced into the landing well 21 and reused for water purification treatment.

  Hereinafter, not only raw water but also what is reused will be described as “treated water”. The agglomeration mixing basin 22 is installed on the downstream side of the landing well 21, and the treated water 1 is introduced from the landing well 21 into the agglomeration mixing basin 22. The agglomeration mixing basin 22 is directly or indirectly connected with a medicine supply means, and the inorganic flocculant 12 is injected into the water 1 to be treated from this supply means.

  The agglomeration mixing basin 22 is provided with stirring means such as a stirring blade and a stirring pump. The stirring means is set with a stirring speed (number of rotations) for applying predetermined stirring energy, and rapidly stirs the water to be treated into which the inorganic flocculant has been injected. The index of agitation energy is not particularly limited, but an example thereof is G value (square root of value obtained by dividing viscosity coefficient μ of water to be treated from work amount P per unit time unit volume, Japan Water Works Association Water Facility Design Guidelines 2000, P188. More).

  As a result of the rapid stirring in the flocculation / mixing pond 22, turbidity in the water to be treated aggregates and grows as fine flocs (micro flocs), and the water to be treated 1 containing fine flocs enters the floc formation pond 23 installed downstream. be introduced.

  As with the agglomeration mixing basin 22, the flock formation pond 23 is provided with stirring means such as a stirring blade and a stirring pump. The stirring means is set at a stirring speed so as to give lower stirring energy (low G value) than the stirring means of the agglomeration mixing basin 22, and the flocs repeatedly contact with each other without collapsing the fine flocs. Is formed.

  The sedimentation basin 24 is installed on the downstream side of the floc-forming basin 23, and the water to be treated including coarse flocs is solid-liquid separated into agglomerated sedimentation sludge 3 and sedimentation supernatant water by gravity sedimentation. The structure of the sedimentation basin 24 is not particularly limited, but generally, an inclined plate or an inclined tube is installed in the inside thereof to promote sedimentation of coarse floc. Usually, the coagulated sediment sludge 3 is accumulated, discharged from the bottom of the sedimentation basin 24, and sent to the concentration means 30.

  The filtration basin 25 is installed on the downstream side of the sedimentation basin 24, and the supernatant liquid that has been subjected to solid-liquid separation in the sedimentation basin 24 is sent to the filtration basin 25 from the end of the sedimentation basin 24. The filter basin 25 has a filter medium. For example, the filter medium is granular, fibrous, or membrane-shaped, and the type and shape thereof are not particularly limited.

  Preferred filter media are granular, for example, filtration sand (silica sand) (effective diameter 0.35 to 1.0 mm, uniformity coefficient 1.7 or less, specific gravity 2.57 to 2.67), anthracite (effective diameter 0). .7 to 4.0 mm, uniformity coefficient of 1.4 or less, specific gravity of 1.4 to 1.6), garnet (effective diameter of about 0.3 mm, uniformity coefficient of 1.5 or less, specific gravity of 3.8 to 4.1), Manganese sand (effective diameter 0.35 to 0.60 mm, uniformity coefficient 1.5 or less, specific gravity 2.58 to 2.65), ceramic (effective diameter 0.3 to 2.0 mm, specific gravity 1.0 to 1.2) 1) or more can be used, but in the case of water supply applications, those containing either one or both of silica sand and anthracite are most preferred, and these filter media are further combined with other filter media. Is also possible. The filter medium may be a single layer or a multilayer structure, and the filter medium and the filter may be combined.

  Residual floc and excess additives (eg, polymer flocculant) in the sediment supernatant are removed by filtration with the above-mentioned filter medium, resulting in clean filtered water. If necessary, a chlorinating agent 13 (for example, sodium hypochlorite, liquid chlorine) is added to this filtered water through a supply means, and treated water 2 (purified water) is obtained.

  In addition, the water purification process means 20 is not limited to the said structure. For example, the chlorine agent 13 may be added to the upstream side of the filtration basin 25 or the landing well 21. Further, when the low turbidity treated water 2 such as underground water is to be treated, the filtration basin 25 is not directly passed through the settling basin 24 but the downstream side of the agglomeration mixing basin 22 or the flock formation basin 23. You may arrange.

  Moreover, you may install the combination of an ozone contact pond and activated carbon adsorption pond in any one or both of the upstream of the filtration basin 25, a downstream. Furthermore, since the development of filtration membranes has been remarkable in recent years, filtration membranes can be used as solid-liquid separation means instead of the filtration basin 25 or in combination with the filtration basin 25.

  Even when the solid-liquid separation means (filter 25) is used, if residual flocs or excessive additives (polymer flocculant, etc.) accumulate due to use, the filtration resistance increases and the filtration efficiency decreases. Therefore, cleaning is performed as necessary. Although the washing method is not particularly limited, the filtration basin 25 is usually washed by back washing, and the waste water after washing is sent to the concentration means 30 as the filtration washing waste water 4. Moreover, the filtration washing waste_water | drain 4 may be sent to the landing well 21 as it is, and may be used for a water purification process again.

  Next, the concentration means 30 will be specifically described. The concentrating means 30 has a drainage basin 31, a drainage basin 32, and a concentration basin 33, and the filtered and washed effluent 4 is sent to the drainage basin 31 and is drained into the drainage basin supernatant 5 and the sludge slurry 6 by gravity settling. After being separated, the drainage basin supernatant 5 is returned to the water purification treatment means 20 (for example, the landing well 21) and again subjected to the water purification treatment. The drainage basin 31 is connected to a mud basin 32, and either one or both of the filtration washing drainage 4 and the sludge slurry 6 derived from the filtration washing drainage 4 are sent to the mud pond 32.

  The drainage basin 32 is also connected to the sedimentation basin 24, and the aggregated sedimentation sludge 3 can be introduced from the sedimentation basin 24 into the sedimentation basin 32 in addition to the filtration washing drainage 4 (sludge slurry 6). The waste mud pond 32 is provided with a stirring means, and the waste mud pond 32 stores the purified water sludge 7 containing at least one of the coagulated sediment sludge 3 and the filtered washing waste water 4 (sludge slurry 6) while stirring. A predetermined amount of the purified water sludge 7 is sent from the waste mud basin 32 to the concentration basin 33 on the downstream side thereof at predetermined intervals or continuously.

  The concentration pond 33 is not particularly limited as long as it is an apparatus capable of concentrating the purified water sludge 7, but the purified water sludge 7 is concentrated by weight concentration and / or mechanical concentration, preferably by weight concentration. The concentrated purified water sludge 7 (concentrated sludge 9) settles, for example, at the bottom of the concentration basin 33 and separates into solid and liquid, and the concentrated pond supernatant 8 is returned to the water purification treatment means 20 (for example, the landing well 21). 9 is sent to the dehydrating means 50.

  The dehydrating means 50 is not particularly limited as long as it removes excess moisture from the concentrated sludge 9, and can be dehydrated by one or both of mechanical dehydration and drying (sunlight or heat drying). Has a dehydrating device 51 for performing at least mechanical dehydration.

  Various mechanical dehydration methods can be used. For example, a belt press type, a centrifugal dehydration type, a screw press type, a vacuum dehydration type, etc. can be used alone or in combination of two or more. The filter press type dehydrator 51 is most preferable in that it is high and the running cost is low.

  The filter press type dewatering device 51 is not particularly limited, such as a filter cloth traveling type, a filter cloth fixed type, a diaphragm type, etc., but any of them is a device that separates moisture from sludge solids through a filter cloth (filter) by pressurization. It is.

  Although the filter is not particularly limited, for example, a fiber having a single fiber diameter of about 0.1 to 0.3 mm is formed into a sheet shape as a nonwoven fabric or a woven fabric (eg, satin weave, plain weave, twill weave, sugi twill weave, felt, double weave). The material is not particularly limited, for example, nylon, polyester, polypropylene, rayon, acetate, promix, cupra, vinylon, vinylidene, polyvinyl chloride, acrylic, polyethylene, polyurethane, carbon fiber, Any one or more kinds of fibers selected from fluorine fibers, polyamides and the like can be used.

  Regardless of which filter is used, the water in the purified water sludge passes through the filter by pressurization and becomes dehydrated water 10, but the solid content does not pass through the filter and is discharged as dehydrated cake 11. On the other hand, the dewatering water 10 is returned to the water purification means 20 (eg, the landing well 21).

  The water purification sludge treatment device 15 further has a supply means 40 for the water purification sludge treatment agent 14, and the supply means 40 is at least one place between the drainage pond 32 and the dehydration device 51, for example, Connected to one or more of the piping connecting the drainage pond 32 to the concentration basin 33 and the piping connecting the concentration basin 33 to the dewatering device 51, and the purified water sludge is connected to one or both of the purified water sludge 7 and the concentrated sludge 9. Treatment agent 14 is added. In addition, a mixing tank may be installed in the addition position of the purified water sludge treatment agent 14 or the downstream side of the addition position, and the purified water sludge treatment agent 14 and the sludges 7 and 9 may be mixed in this mixing tank.

  Although the supply means 40 is not specifically limited, Preferably, a dissolution tank is installed, and an aqueous solution in which the purified water sludge treatment agent 14 is dissolved or dispersed is accommodated in the dissolution tank. A desired amount of the purified water sludge treatment agent 14 can be injected by adjusting the flow rate of one or both of the aqueous solution and the treated sludge with the flow rate control means.

  Next, the purified water sludge processing method using this purified water sludge processing apparatus 15 is demonstrated.

[Purified water sludge treatment method]
The treated water 1 to be treated in the present invention is not particularly limited, and it is possible to treat industrial wastewater, domestic wastewater, seawater, etc., but particularly suitable are river water, lake water, reservoir water, rainwater, underground flow Water, groundwater and well water.

If necessary, the water quality of the water to be treated 1 is examined in advance by a jar test or the like, and the injection amount of the inorganic flocculant is set in advance according to the water quality, and is 5 to 200 mg, preferably 10 to 100 mg per liter of water to be treated. The inorganic flocculant 12 is injected in an added amount and rapidly stirred in the flocculation mixing tank 22. In addition, the said addition amount is the mass of solid content, when an inorganic flocculant is aluminum sulfate or ferric chloride, and an inorganic flocculant is PAC (a polyaluminum chloride solution of 10 mass% in terms of aluminum oxide Al ₂ O ₃ ). Is the mass of the liquid.

  Next, the water to be treated in which the fine flocs are generated is gently stirred in the floc formation pond 23 to coarsen the flocs. If necessary, an appropriate amount of a polymer flocculant for floc growth (about 0.05 to 20 mg per 1 liter of water to be treated) may be added before the start of the slow stirring or during the slow stirring. Furthermore, together with the inorganic flocculant or the polymer flocculant or separately from these flocculants, one or more additives such as a pH adjuster, a buffer, a flocculant aid, a bactericidal agent, and a sedimentation accelerator may be added. Good.

  The treated water 1 on which the coarse floc has grown is solid-liquid separated in the sedimentation basin 24, and the separated sediment supernatant is filtered through the filtration basin 25 to become a clear filtered water. ) On the other hand, the agglomerated sedimentation sludge 3 that has been separated by sedimentation is sent to the waste mud pond 32.

  On the other hand, the filter basin 25 is washed (backwashed) periodically or when it is determined that the filter resistance has reached a certain level or more based on the inspection result. The filtered and washed waste water 4 is sent to the drainage basin 31 together with the solid content (residual floc and excess additive) peeled off from the filter medium, and is separated into solid and liquid into the drainage basin supernatant 5 and the sludge slurry 6. In the sludge pond 32, the sludge slurry 6 (filtered washing waste water 4) and the coagulated sediment sludge 3 are arbitrarily mixed to obtain the purified water sludge 7.

  The purified water sludge 7 is stirred in the waste mud pond 32 and sent to the concentration basin 33 in a state where the solid content is uniformly dispersed. If the purified water sludge treatment agent 14 is added to the purified water sludge 7, the sedimentation property of the sludge in the concentration pond 33 is improved, so that the concentrated sludge 9 having a high concentration can be obtained by gravity concentration or mechanical concentration. The clarity of the clear water 8 is improved. The amount of the purified water sludge treatment agent 14 added at the time of sludge concentration is, for example, about 0.01 to 3% by mass, preferably about 0.1 to 1% by mass with respect to the dry sludge equivalent weight (SS) of the purified water sludge 7. Depending on the concentration conditions, it can be appropriately changed.

  Concentrated sludge 9 is one or more mechanical dehydration methods selected from pressure filtration, pressure squeezing filtration, vacuum filtration, centrifugal separation, granulation dehydration, and drying, and attachment or drying by heat drying. It is dehydrated by any one or more of the methods, preferably by mechanical dehydration, more preferably by pressure filtration or pressure squeeze filtration.

  In any dewatering method, when the concentrated sludge contains the purified water sludge treatment agent 14, the dewaterability is improved, the moisture content of the dewatered sludge (dehydrated cake 11) is lowered, and the filter cloth peelability of the dewatered sludge is also improved. The dehydration process can be performed efficiently.

  The purified water sludge treatment agent 14 used in the dehydration process may be a residue derived from the purified water sludge 7 used for sludge concentration, or may be added to the concentrated sludge 9 after sludge concentration. When added to the concentrated sludge 9, the amount of the purified water sludge treatment agent 14 added is, for example, 0.005 to 2% by mass, preferably 0.05 to 0.5%, based on the dry sludge equivalent weight (SS) of the concentrated sludge 9. Although it is about mass%, it can be appropriately changed depending on the dehydration conditions.

  The dewatered concentrated sludge 9 is discharged as a dehydrated cake 11 and can be recycled to roadbed materials, soil conditioners, cement materials, etc., and may be incinerated or landfilled as waste.

  On the other hand, the supernatant water and detachment water generated by the concentration means 30 and the dewatering means 50, specifically, the drainage pond supernatant water 5, the concentration pond supernatant water 8, and the dewatering detachment water 10 are all purified water treatment means 20 (eg, landing well 21). And is subjected to a water purification treatment step together with the water 1 to be treated and the filtration washing waste water 4 or separately from the water to be treated 1 and the filtration washing waste water 4.

  Therefore, since the supernatant waters 5 and 8 and the separated water 10 can be reprocessed without flowing out of the treatment system of the purified water sludge treatment device 15, the purified water sludge treatment agent 14 is added to the supernatant waters 5 and 8 and the separated water 10. Even if the additive or its additive (polymer flocculant) remains, it can be supplemented without causing these residual substances to flow out of the processing system. In addition, the purified water sludge treatment agent 14 remaining in the supernatant waters 5 and 8 and the detached water 10 contributes to the coarsening of the flocs flocs and forms strong coarse flocs. It is also possible to suppress the amount used.

  In the case of reprocessing the supernatant waters 5 and 8 and the detached water 10, conventionally, the increase in the filter resistance of the filter basin 25 due to residual substances has become a problem. Even if the purified water sludge treatment agent 14 of the present invention remains in the supernatant waters 5 and 8 and the separated water 10, the effect of the filter resistance is suppressed to the same level or lower than that when the inorganic flocculant only aggregates, precipitates and filters. Is done. That is, compared with the case where the conventional sludge treatment agent is used, if the purified water sludge treatment agent 14 of the present invention is used, the filtration failure due to the reprocessing of the supernatant waters 5 and 8 and the separated water 10 hardly occurs.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. Six types of polymers I to VI were prepared as the purified water sludge treatment agent of the present invention, and five types of comparative polymers I to V were prepared as comparison targets. The compositions are listed in Tables 1 and 2 below.

  In Table 1 above, component A represents polyacrylic acid Na (homopolymer), component B is a mixture of polyacrylic acid Na and sodium alginate, and component C is a mixture of polyacrylic acid Na and carboxymethylcellulose Na. The component D is a mixture of polyacrylic acid Na and polyacrylamide Na, and the polyacrylamide Na of the component D is an anionic polycarboxylic acid copolymer containing a carboxyl group in its anionic structural unit (acrylamide and acrylic). Copolymer of acid Na).

  The component D of the said Table 2 is a mixture of polyacrylic acid Na and polyacrylamide Na which is an anionic polycarboxylic acid copolymer like the component D of Table 1.

<Sludge slurry concentration test>
A sludge slurry concentration test was conducted using the above polymers I to VI and comparative polymers I to V. The types and injection rates of Polymers I to VI and Comparative Polymers I and II as purified water sludge treatment agents are shown in Table 3 below together with the test results.

<Comparative Example 1>
Reagents Kaolin (hereinafter referred to as “kaolin”) manufactured by Wako Pure Chemical Industries, Ltd. and polyaluminum chloride A-250 (hereinafter referred to as “PAC”) manufactured by Taki Chemical Co., Ltd. in Sodegaura city water at a mass ratio of 1: 2. The mixture was added and mixed, and neutralized to pH 7 with sodium hydroxide to prepare a sludge slurry stock solution. The solid concentration (SS) of this sludge slurry stock solution was measured and diluted with Sodegaura City water based on this value to prepare a sludge slurry with an SS concentration of 1.3 g / L.

Collect 200 mL of this sludge slurry in a beaker, stir the impeller at 150 rpm for 2 minutes with a jar tester without adding polymers I to VI (comparative polymers I to V), transfer to a stoppered graduated cylinder and mix and stand. The volume occupied by the precipitated slurry after 2 minutes was measured from the slurry interface. The slurry volume% was 85% was determined (hereinafter, SV ₂ hereinafter). Further, the mixture was left standing, and after 30 minutes, 100 mL of supernatant water (hereinafter referred to as concentrated supernatant water) was collected and measured for turbidity using a turbidimeter WA 6000 manufactured by Nippon Denshoku Industries Co., Ltd. The degree exceeded 30 degrees.

  Next, No. 150 mm in diameter. Place 5 types A quantitative filter paper into 16-fold folds, place it in a funnel, and after 30 minutes of standing, pour 100 mL of supernatant water all at once and measure the amount of water (mL) to be filtered in 30 seconds (hereinafter referred to as this The measured value was described as a concentrated supernatant water filtration index) and found to be 65 mL / 30 seconds.

<Example 1>
As purified water sludge treatment agent, except that the polymer I is added to the sludge slurry injection rate in Table 3 was subjected to the sludge slurry concentration test in the same conditions as in Comparative Example 1, SV ₂ is 28%, concentrated on supernatant water turbidity Was 8.3 degrees and the concentrated supernatant water filtration index was 72 mL / 30 seconds. That is, in Example 1, both SV ₂ and concentrated supernatant water turbidity are lower than those in Comparative Example 1, the concentration of sludge slurry and the clarity of the supernatant water are remarkably improved, and higher than or equal to Comparative Example 1. Filtration index is obtained. Comparative Example 1 is considered to be applicable when water purification treatment (flocculation, precipitation, filtration) is performed using only an inorganic flocculant without addition of a polymer, and the present invention is such Comparative Example 1 It was confirmed that the resistance was reduced.

<Example 2>
Where except for changing the injection rate of the polymer I is a purified water sludge treatment agent 0.3 mass% (vs. SS) is subjected to the sludge slurry concentration test under the same conditions as in Example 1, SV ₂ is 27%, the concentrated The clear water turbidity is 1.5 degrees, the concentrated supernatant water filtration index is 81 mL / 30 seconds, and all of SV ₂ , concentrated supernatant water turbidity and concentrated supernatant water filtration index are improved from those of Comparative Example 1 and Example 1. It was done.

<Example 3 to Example 7>
A sludge slurry concentration test was conducted under the same conditions as in Example 1 except that the purified water sludge treatment agent was changed to polymers II to VI and added at the injection rate shown in Table 3 above. Example 3, Example 4, Example 5, example 6, SV ₂ respectively 27% in example 7, 27%, 28%, 21%, 22%, respectively concentrated on supernatant water turbidity 4.5 degrees, 5.4 degrees, 5.2 degrees , 1.6 degrees, 1.8 degrees, respectively concentrated on supernatant water filtration index 78 mL / 30 sec, 70 mL / 30 sec, 66 mL / 30 sec, 75 mL / 30 seconds, a 66 mL / 30 sec, SV _2, the concentrated Both the clear water turbidity and the concentrated supernatant filtration index were improved as compared with Comparative Example 1. However, when compared at the same rate of injection (0.3%), Examples 4 to 7 are inferior to Examples 2 and 3 in terms of the filtration index of the concentrated supernatant water, and filter resistance suppression is particularly required. In this case, it is understood that a purified water sludge treatment agent mainly composed of poly (meth) acrylate is suitable.

<Comparative Example 2 and Comparative Example 3>
When the sludge slurry concentration test was performed under the same conditions as Example 1 except that Comparative Polymer I was added at the injection rate shown in Table 3 as a purified water sludge treatment agent, SV ₂ of Comparative Example 2 and Comparative Example 3 were respectively 26%, 23%, and concentrated supernatant turbidity were 2.0 degrees and 2.3 degrees, respectively. Although these results were improved over Comparative Example 1, the concentrated supernatant filtration index was 48 mL / 30 seconds, respectively. 35 mL / 30 seconds, which is significantly lower than that of Comparative Example 1, and it was confirmed that the risk of filtration failure was higher than that of Comparative Example 1.

<Comparative Example 4 and Comparative Example 5>
When the sludge slurry concentration test was performed under the same conditions as in Example 1 except that Comparative Polymer II was added at the injection rate shown in Table 3 as a purified water sludge treatment agent, SV ₂ of Comparative Example 4 and Comparative Example 5 were respectively 24%, 23%, and concentrated supernatant turbidity were improved to 3.2 degrees and 0.3 degrees, respectively, compared to Comparative Example 1, but the concentrated supernatant filtration index was 35 mL / 30 seconds and 36 mL / 30 seconds, respectively. It was significantly less than Comparative Example 1, and it was confirmed that Comparative Examples 4 and 5 had a high filtration failure risk as in Comparative Examples 2 and 3.

  Next, the concentration test was performed by increasing the concentration of the sludge slurry. The types of polymers I to VI and comparative polymers I to V as purified water sludge treatment agents are listed in Table 4 below together with the test results.

<Comparative Example 6>
A sludge slurry concentration test was conducted under the same conditions as in Comparative Example 1 except that the sludge slurry prepared to an SS concentration of 2.0 g / L was used for the test. SV ₂ was 99%, and the concentrated supernatant water turbidity was 30 degrees. The concentrated supernatant water filtration index was 61 mL / 30 seconds.

<Examples 8 to 13>
As a purified water sludge treatment agent, a sludge slurry concentration test was conducted under the same conditions as in Comparative Example 6 except that Polymer I to Polymer VI were respectively added to the sludge slurry at an injection rate of 0.3 mass% to SS. 8, example 9, example 10, example 11, example 12, SV _2, respectively 39% in example 13, 37%, 35%, 35%, 55%, 50%, concentrated on supernatant water turbidity 1.7 degree, 1.0 degree, 8.2 degree, 7.2 degree, 0.4 degree, 0.4 degree respectively, and concentrated supernatant water filtration index is 86 mL / 30 seconds, 82 mL / 30 seconds, 67 mL / 30 seconds, 62 mL / 30 seconds, 68 mL / 30 seconds, and 68 mL / 30 seconds. In these Examples 8 to 13, the concentration of sludge slurry and the clarity of the supernatant water were remarkably improved as compared with Comparative Example 6. The filtration index is higher than Comparative Example 6, and the filter resistance is reduced. It was confirmed.

  Moreover, even when SS concentration is high, Examples 8 and 9 using polyacrylic acid Na alone are superior in each stage in terms of filtration index than Examples 10 to 13 using mixtures with other polymers. In the case where suppression of filter resistance is particularly required, it is understood that a purified water sludge treatment agent mainly composed of poly (meth) acrylate is particularly suitable.

<Comparative Example 7 to Comparative Example 11>
As the purified water sludge treatment agent, a comparative sludge slurry concentration test was performed under the same conditions as in Comparative Example 6 except that Comparative Polymer I to Comparative Polymer V were respectively added to the sludge slurry at an injection rate of 0.3% by mass to SS. Comparative example 7, Comparative example 8, Comparative example 9, Comparative example 10, SV _2, respectively 31% Comparative example 11, 33%, 24%, 25%, 57%, concentrated on supernatant water turbidity respectively 0.4 ° 1.7 degree, 2.1 degree, 2.4 degree, 0.5 degree, concentrated supernatant water filtration index is 49 mL / 30 seconds, 48 mL / 30 seconds, 45 mL / 30 seconds, 43 mL / 30 seconds, 48 mL / Although it was 30 seconds and SV ₂ and concentrated supernatant turbidity were improved as compared with Comparative Example 6, the concentrated supernatant filtration index was lower than that of Comparative Example 6 and it was confirmed that the risk of filtration failure was high.

<Dehydration test>
Next, the dewaterability of the concentrated sludge of the water purification sludge treatment agent was examined. Dehydration conditions and dehydration test results are shown in Table 5 below.

<Comparative Example 12>
Kaolin and PAC were added to Sodegaura city water at a weight ratio of 1: 2, mixed and neutralized to pH 7 with sodium hydroxide to prepare a sludge slurry stock solution. The solid concentration (SS) of this sludge slurry stock solution was measured, and based on the measured value, diluted with Sodegaura City water to prepare concentrated sludge having an SS concentration of 20 g / L, and subjected to a concentrated sludge dehydration test.

  Collect 200 mL of the above concentrated sludge in a container, transfer to another container 5 times and mix (corresponds to the “transfer 5 times agglomeration method” agglomeration operation described later), then high-speed centrifugation manufactured by Tommy Industries Using the machine MX-307, solid-liquid separation was performed under the condition of a rotational speed of 5000 rpm × 2 minutes, and a supernatant and precipitated sludge were collected.

  For the supernatant, No. 150 mm in diameter. Place the 5 types A quantitative filter paper into 16-fold folds and place in a funnel. When weighed, it was 58 mL / 30 seconds.

  For precipitated sludge, put it into a conical filter with a 40 mesh screen (made in-house), drain the water by gravity filtration, insert the sludge after draining into a polyester filter cloth, and then pressurize the piston type pressure dehydrator (made in-house). : The surface pressure was 0.04 MPa), and after dewatering for 2 minutes, the dewatered cake peeled from the filter cloth was evaluated for sludge peelability from the filter cloth and the moisture content. It was 83.5 mass%.

<Examples 14 and 15>
As the purified water sludge treatment agent, the polymer I of the present invention described in Table 1 was added to the concentrated sludge at an injection rate of 0.15 mass% to SS and 0.20 mass% to SS, respectively. The concentrated sludge dewatering test was conducted under the same conditions as in Comparative Example 12 except that the flocculation operation by the “method” was carried out. / 30 seconds, the sludge peelability of the dewatered sludge cake was “good”, and the moisture content was 76.5% by mass and 73.2% by mass, respectively. That is, compared with Comparative Example 12, Examples 14 and 15 were improved when the sludge dewatering property and sludge removability were improved, and filtration was performed when dehydrated and separated water (centrifugal supernatant) was returned to the water purification system. It was confirmed that the pond blockage risk was also reduced rather than the case of performing coagulation sedimentation filtration using only the inorganic coagulant (Comparative Example 12).

<Example 16, Example 17>
As the purified water sludge treatment agent, the above Example 14, except that the polymer II of the present invention described in Table 1 was added to the concentrated sludge at an injection rate of 0.15 mass% to SS and 0.20 mass% to SS, respectively. When the concentrated sludge dewatering test was performed under the same conditions as in No. 15, the concentrated sludge centrifugal liquid filtration indexes of Example 16 and Example 17 were 66 mL / 30 seconds and 76 mL / 30 seconds, respectively, and the sludge stripping property of the dewatered sludge cake was “Good” and moisture content were 73.1% by mass and 72.5% by mass, respectively, and both indicators were improved from Comparative Example 12.

<Example 18 and Example 19>
Concentrated under the same conditions as in Examples 14 and 15 above, except that the polymers III and IV of the present invention listed in Table 1 were added to the concentrated sludge at an injection rate of 0.20% by mass to SS, respectively, as a purified water sludge treatment agent. When the sludge dewatering test was performed, the filtration indexes of the concentrated sludge centrifuges of Example 18 and Example 19 were 76 mL / 30 seconds and 68 mL / 30 seconds, respectively, and the sludge release property of the dewatered sludge cake was “good”. The rates were 78.0% by mass and 78.5% by mass, respectively, and both indicators were improved from Comparative Example 12.

<Example 20 and Example 21>
As the purified water sludge treatment agent, Example 14 except that the polymer V of the present invention described in Table 1 was added to the concentrated sludge at an injection rate of 0.15 mass% to SS and 0.20 mass% to SS, respectively. When the concentrated sludge dewatering test was conducted under the same conditions as in No. 15, the concentrated sludge centrifugal filtration index of Example 20 and Example 21 was 70 mL / 30 seconds and 62 mL / 30 seconds, respectively, and the sludge stripping property of the dewatered sludge cake was “Good”, the moisture content was 72.0% by mass and 71.5% by mass, respectively, and both indicators were improved from Comparative Example 12.

<Example 22 and Example 23>
Example 14 except that the polymer VI of the present invention described in Table 1 was added to the concentrated sludge at an injection rate of 0.15 mass% to SS and 0.20 mass% to SS, respectively, as a purified water sludge treatment agent. 15 Concentrated sludge dewatering tests were performed under the same conditions. As a result, the concentrated sludge centrifugal liquid filtration indexes of Example 22 and Example 23 were 66 mL / 30 seconds and 65 mL / 30 seconds, respectively. “Good” and water content were 72.2% by mass and 76.5% by mass, respectively, and both indicators were improved from Comparative Example 12.

<Comparative Example 13 and Comparative Example 14>
Concentrated sludge dewatering under the same conditions as in Examples 14 and 15, except that Comparative Polymer I was added to the concentrated sludge at a rate of 0.15% by mass to SS and 0.20% by mass to SS as the purified water sludge treatment agent, respectively. When the tests were conducted, the concentrated sludge centrifugal liquid filtration indexes of Comparative Example 13 and Comparative Example 14 were 39 mL / 30 seconds and 30 mL / 30 seconds, respectively, the sludge peelability of the dewatered sludge cake was “good”, and the water content was Although they were 76.5% by mass and 73.5% by mass, respectively, the sludge removability and water content were improved as compared with Comparative Example 12, but the concentrated sludge centrifugal liquid filtration index was lower than that of Comparative Example 12, and the dehydrated and separated water ( The filtration clogging risk given to the filtration pond when the centrifuged supernatant was returned to the water purification system was higher than that of Comparative Example 12.

<Comparative Example 15 and Comparative Example 16>
Concentrated sludge dewatering under the same conditions as in Examples 14 and 15 except that Comparative Polymer II was added to the concentrated sludge at a filling rate of 0.15% by mass to SS and 0.20% by mass to SS, respectively, as a purified water sludge treatment agent. When the tests were performed, the concentrated sludge centrifugal liquid filtration indexes of Comparative Example 15 and Comparative Example 16 were 45 mL / 30 seconds and 40 mL / 30 seconds, respectively, the sludge peelability of the dewatered sludge cake was “good”, and the water content was Although 76.5% by mass and 72.5% by mass, respectively, the sludge removability and the water content were improved from Comparative Example 12, but the dehydrated and separated water (centrifugal supernatant) was returned to the water purification system. The filtration blockage risk given to the filtration pond was higher than that of Comparative Example 12.

<Comparative Example 17 and Comparative Example 18>
Concentrated sludge dewatering test under the same conditions as in Examples 14 and 15 except that Comparative Polymer III was added to the concentrated sludge at a rate of injection of 0.15 mass% to SS and 0.20 mass% to SS, respectively, as a water purification sludge treatment agent. As a result, the filtration indexes of the concentrated sludge centrifuges of Comparative Example 17 and Comparative Example 18 were 45 mL / 30 seconds and 34 mL / 30 seconds, respectively, the sludge removability of the dewatered sludge cake was “good”, and the water content was respectively Although it is 80.0 mass% and 80.2 mass%, sludge peelability and water content were improved from Comparative Example 12, dehydration separation water (centrifugation supernatant) was returned to the water purification system. The filtration blockage risk given to the pond was higher than in Comparative Example 12.

<Comparative Example 19 and Comparative Example 20>
Concentrated sludge dewatering test under the same conditions as in Examples 14 and 15 except that Comparative Polymer IV was added to the concentrated sludge at a rate of 0.15% by mass to SS and 0.20% by mass to SS, respectively, as a purified water sludge treatment agent. As a result, the filtration indexes of the concentrated sludge centrifugal liquids of Comparative Example 19 and Comparative Example 20 were 44 mL / 30 seconds and 28 mL / 30 seconds, respectively, the sludge removability of the dehydrated sludge cake was “good”, and the water content was respectively Although it is 74.5 mass% and 72.5 mass%, sludge removability and water content were improved from Comparative Example 12, dehydration separation water (centrifugation supernatant) was returned to the purified water treatment system. The filtration blockage risk given to the pond was higher than in Comparative Example 12.

<Comparative Example 21>
As a purified water sludge treatment agent, a concentrated sludge dehydration test was conducted under the same conditions as in Examples 14 and 15 except that Comparative Polymer V was added to the concentrated sludge at an injection rate of 0.20% by mass to SS. Comparative Example 21 Concentrated sludge centrifuge filtration index was 45 mL / 30 seconds each, dewatered sludge cake sludge releasability was “good”, moisture content was 72.3 mass%, and sludge releasability and moisture content were improved over Comparative Example 12. However, the filtration clogging risk given to the filtration pond when the dewatered water (centrifugal supernatant) was returned to the water purification system was higher than that of Comparative Example 12.

  As described above, if the water purification sludge treatment agent of the present invention is used, not only can the concentration of the sludge slurry and the dewaterability of the concentrated sludge be improved, but also the concentration that has been a problem when using conventional acrylamide polymer flocculants The risk of causing filtration failure in the filtration pond when the pond water or dewatered water is returned to the water purification system can be dramatically reduced.

1 treated water (raw water)
2 treated water (purified water)
DESCRIPTION OF SYMBOLS 3 Coagulation sedimentation sludge 4 Filtrate washing drainage 5 Drainage pond supernatant water 6 Sludge slurry 7 Purified sludge 8 Concentration pond supernatant water 9 Concentrated sludge 10 Dehydrated removal water 11 Dehydrated cake 12 Inorganic flocculant 13 Chlorine agent 14 Purified sludge treatment agent 15 Purified sludge treatment equipment 20 Water treatment means 21 Landing well 22 Coagulation and mixing pond 23 Flock formation pond 24 Precipitation pond 25 Filtration basin 30 Concentration means 31 Drainage pond 32 Mud basin 33 Concentration basin 40 Supply means 50 Dehydration means 51 Dehydration device

Claims (6)

Containing a polycarboxylic acid polymer,
0.1 mass% salt viscosity when dissolved in 1 mol / L sodium chloride solution is 2 to 5 mPa · s, and 0.1 mass% solution viscosity when dissolved in 25 g / L sodium chloride solution is 6 mPa · s or less. And a purified water sludge treatment agent, wherein the anion equivalent is 4.5 meq / g or more.   The water purification sludge treatment agent according to claim 1, wherein the polycarboxylic acid-based polymer contains poly (meth) acrylic acid or a salt thereof. After coagulating and precipitating the water to be treated, it is filtered to obtain purified water by filtration,
A concentration step for concentrating purified water sludge separated from the water purification treatment step and purified water sludge containing at least one of filtration washing wastewater discharged from the apparatus used for the filtration to obtain a concentrated sludge;
A dehydration step of dehydrating the concentrated sludge,
A purified water sludge treatment further comprising a supply step of a purified water sludge treatment agent to which the purified water sludge treatment agent according to claim 1 or 2 is added to one or both of the purified water sludge and the concentrated sludge. Method.   The water purification sludge treatment method according to claim 3, wherein the dehydration step is mechanical dehydration using a filter press. Water purification treatment means for coagulating and precipitating the treated water and filtering to obtain purified water;
Concentrating means for concentrating purified water sludge separated by the water purification treatment means and at least one of filtration washing wastewater discharged from the apparatus used for the filtration to obtain concentrated sludge;
Dehydrating means for dewatering the concentrated sludge;
Supply means for adding the purified water sludge treatment agent according to claim 1 or 2 to any one or both of the purified water sludge and the concentrated sludge,
A purified water sludge treatment apparatus characterized by comprising:   6. The water purification sludge treatment apparatus according to claim 5, wherein the dewatering means is a filter press type dewatering means.

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