JP3951115B2 - Sludge concentrator - Google Patents

Description

【００１６】
なお、表１における処理条件は次の通りである。
原泥として汚泥濃度１．５％（質量％）の下水混合生汚泥を１０ｍ³／時間の供給量で凝集反応槽に供給して、凝集処理および濃縮処理を行った。使用した凝集剤は、無機凝集剤としてポリ硫酸第二鉄、有機凝集剤として両性高分子凝集剤である。
【００１７】
表１の無機凝集剤（あるいは高分子凝集剤）の濃度は、下水混合生汚泥の汚泥濃度、供給量および無機凝集剤、高分子凝集剤の濃度、供給量から決まる固形成分等の単位体積当たりの総質量（Ｔｏｔａｌ Ｓｏｌｉｄ（ＴＳ））に占める無機凝集剤（あるいは高分子凝集剤）における固形成分等の総質量の割合を表す。そこで、この濃度の表示を（質量％／ＴＳ）とした。
【００１８】
濃縮汚泥濃度は、濃縮後における汚泥固形成分等の濃縮汚泥中の濃度（質量％）である。
ＳＳ（懸濁物質）回収率は、投入される下水混合生汚泥中のＳＳ全量に対する汚泥濃縮後に回収される濃縮汚泥中のＳＳ全量の割合を表す。
濃縮汚泥の脱水性の評価は、相対評価であるが、◎が非常に良い、○が良いを表わす。
【００１９】
表１から、本発明の実施形態に係る汚泥濃縮装置は、従来の汚泥濃縮装置に比べて良好な濃縮の達成、すなわち、従来の汚泥濃縮装置に比べて少ない凝集剤の添加でより高い濃縮性能、および汚泥凝集、濃縮過程におけるより少ない汚泥損失の達成ができることが裏付けられた。具体的には、表１は次のような本発明の実施形態の特長を示している。第一に、本発明の実施形態における高分子凝集剤の濃度を従来装置における濃度の５分の４（０．８％／ＴＳ）に設定した場合であっても、濃縮汚泥濃度は５％となり、従来装置の場合に対して２５乃至６６％増加する。第二に、ＳＳ回収率は従来装置に比べて２乃至４％増加し９９％となる。第三に、上記第一および第二のような特性が得られることにより、本発明の実施形態による汚泥の脱水性は、従来装置の相対評価 “良い”に対し、“非常に良い”に相当するものである。
【００２０】
尚、本発明は上記した一実施形態に限定されるものではない。本発明の汚泥濃縮装置は、実施形態で例示した濃縮機の他、例えば、造粒濃縮装置、ウェッジワイヤ型スクリーン、ドラム型スクリーン等のように、汚泥濃縮に供せられるものであれば、どのようなもので使用できる。
本発明の汚泥排出路は、実施形態においては凝集反応槽の上端近傍壁面に配置したが、濃縮機、汚泥供給路および汚泥還流路のいずれの一部に配置してもよい。
【００２１】
さらに、本発明の汚泥濃縮装置は、実施形態においては凝集反応槽と濃縮機を一つずつ備えているが、凝集反応槽と濃縮機を複数備えてもよく、これらの配列は直列でも並列でもよい。
【００２２】
【発明の効果】
本発明の汚泥濃縮装置は、凝集反応槽と濃縮機との間で汚泥を還流させて凝集と濃縮を繰り返すので、凝集フロックの粒径を容易に大きくでき、且つ、その緻密度および機械的強度を増大することができる。その結果、濃縮汚泥の濃縮度向上を可能にする。また、高分子凝集剤の添加率を低くしてもＳＳ回収率を高められ、汚泥濃縮の高効率化が達成できる。さらに、従来の既設のいずれの濃縮装置を利用・転用しても簡単に本発明の汚泥濃縮装置を設備することができる簡便さがある。
【００２３】
したがって、この汚泥濃縮装置により、下水、し尿、廃水等の汚泥の凝集・濃縮において汚泥の減容化が一段と進み、汚泥の脱水処理、移送等の扱い易さに寄与することができるとともに、材料費の軽減、既存の従来の濃縮装置の有効利用が可能となる。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る汚泥濃縮装置を示す概略図である。
【符号の説明】
１ 汚泥濃縮装置
２ 凝集反応層
３ 濃縮機
４ 汚泥供給路
５ 汚泥還流路
２２ 原泥供給管
２３ 凝集剤供給管
２４ 撹拌手段
３３ 圧送手段
３５ 濾過フィルタ
３７ 螺旋状スクリュー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sludge concentrating device suitable for aggregating and concentrating sludge generated in the treatment of sewage, human waste, wastewater, and the like.
[0002]
[Related background]
Sludge generated in the treatment of sewage, human waste, wastewater, etc. has a high moisture content. Therefore, the sludge is agglomerated and separated into agglomerated sludge having a higher moisture content and solid content concentration to reduce the volume of the sludge. In order to improve the sludge dewatering efficiency and reduce the transfer capacity, the condensed sludge is further concentrated.
[0003]
Conventionally, a granulating and concentrating apparatus has been used exclusively for such sludge aggregation and concentration.
The granulation concentrator is disclosed in, for example, Japanese Patent No. 2554545. This granulation concentration apparatus has a structure in which a concentration tank is provided on the upper part of a sludge aggregation tank via a filtration filter. Then, flocs are grown by stirring and mixing the sludge supplied to the concentration tank and the flocculant to form agglomerated sludge, and this agglomerated sludge is passed through a filter to be concentrated to the concentration tank. It has become.
[0004]
[Problems to be solved by the invention]
However, the granulation concentration apparatus has the following problems. First, the opening width of the slit of the filtration filter provided in the concentration tank is 1 to 2 mm, and SS (suspended substance) leaks from the concentration tank side to the separation liquid side when the floc is small. Secondly, sludge tends to adhere to the filter and cannot be removed sufficiently. Thirdly, the filtration filter is provided in the upper part of the coagulation tank, and the area of this part is limited, so there is an upper limit on the area of the filtration filter, and the amount of sludge treatment is inevitable. Fourth, the circulation flow of flocs tends to be non-uniform in the coagulation tank, and the raw sludge, the coagulant and the coagulated sludge tend to stay. Therefore, there is a problem that the particle size of the aggregated floc cannot be grown sufficiently large, and the mechanical strength of the aggregated floc cannot be sufficiently increased.
[0005]
On the other hand, it is conceivable to concentrate the coagulated sludge aggregated in the coagulation tank using a double cylinder type concentrator. However, even if such a double cylinder type concentrator is used, the growth of the particle size of the aggregate floc in the coagulation tank is not sufficient, and the problem that the mechanical strength cannot be sufficiently increased cannot be solved.
The present invention has been made to solve the above-mentioned problems, and can sufficiently increase the particle size of the flocs flocs and increase the density and mechanical strength thereof. As a result, the concentrated sludge is concentrated. It aims at providing the sludge concentration apparatus which can improve a degree.
[0006]
[Means for Solving the Problems]
According to the present invention, in order to achieve the above object, a coagulation reaction tank that reacts sludge with a flocculant to generate coagulated sludge, and the coagulated sludge extracted from the coagulation reaction tank is concentrated to concentrate sludge. A sludge supply path for supplying the sludge from the agglomeration reaction tank to the concentrator, and a sludge ring channel for circulating the concentrated sludge generated by the concentrator to the agglomeration reaction tank. A sludge concentrator,
In particular, as the concentrator, a cylindrical body is provided with a filtration filter on the peripheral wall, and the agglomerated sludge extracted from the agglomeration reaction tank is introduced from one end thereof,
A spiral screw that is coaxially provided inside the cylindrical body and is driven to rotate, and guides the aggregated sludge to the other end while compressing the sludge,
An envelope that covers the cylindrical body and collects the separated liquid separated from the agglomerated sludge through the filtration filter and discharges the separated liquid to the outside;
A sludge concentrating device equipped with is provided.
[0007]
Preferably, according to the present invention, the agglomeration reaction tank guides the agglomerated sludge produced by reacting the sludge introduced from the lower part with the aggregating agent to the upper part thereof. Is provided .
[0008]
According to a preferred embodiment, the sludge circulation system for circulating the coagulated sludge between the coagulation reaction tank and the concentrator is a sludge discharge channel for branching the sludge from the sludge circulation system and discharging the concentrated sludge to the outside. A sludge condensing device is provided.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Below, one embodiment concerning the sludge concentration apparatus of the present invention is explained in full detail based on FIG.
FIG. 1 is a schematic view of a sludge concentrating device 1. The sludge concentrating device 1 includes a flocculation reaction tank 2, a concentrator 3, a sludge supply path 4 and a sludge ring path 5.
The agglomeration reaction tank 2 includes a raw mud supply pipe 22 for supplying raw sludge to the bottom of a cylindrical reaction tank 21 and a flocculant supply pipe 23 for supplying a flocculant. The reaction tank 21 is provided with a stirring means 24 that is rotationally driven by a motor 20 provided coaxially in the reaction tank 21 in order to stir the sludge and the flocculant to promote the generation of the agglomerated sludge. For example, the stirring unit 24 includes rotating blades 26a and 26b attached at different positions in the vertical direction of the rotating shaft 25 with a phase of 180 degrees. Further, a supply outlet 27 for supplying the coagulated sludge to the concentrator is provided on the wall surface near the upper end of the reaction tank 21, and a recirculation inlet 28 through which the concentrated sludge is circulated is provided on the side face near the lower end of the reaction tank 21. ing. Further, the reaction tank 21 is provided with a sludge discharge passage 29 for discharging the aggregated sludge on the wall surface near the upper end. The agglomerated sludge discharged from the sludge discharge passage 29 is further dehydrated by a dehydrator (not shown).
[0010]
The sludge supply path 4 is provided for supplying the coagulated sludge from the coagulation reaction tank 2 to the concentrator 3 through the supply outlet 27.
On the other hand, the concentrator 3 includes a cylindrical body 31 and an envelope 32 provided to cover the cylindrical body 31. The cylindrical body 31 is provided with a supply inlet 34 through which the agglomerated sludge is supplied from the agglomeration reaction layer 21 on the wall surface near the upper end thereof, and a filtration filter 35 for separating and filtering the liquid contained in the sludge on the peripheral wall. It has. The filtration filter 35 is made of, for example, a punching plate or / and a wedge wire, and the hole diameter of the punching plate or the slit width of the wedge wire is arbitrarily selected. Increases floc separation performance. Further, the cylindrical body 31 is provided with a reflux outlet 38 on the wall surface near the lower end thereof for refluxing concentrated sludge to the agglomeration reaction tank 21 through the sludge ring flow path 5. Further, the cylindrical body 31 is provided with a pressure feeding means 33 for transporting the sludge supplied from the supply inlet 34 toward the reflux outlet 38 while compressing the sludge. The pressure feeding means 33 includes a screw rotating shaft 36 coaxially provided inside the cylindrical body 31 and a helical screw 37 attached to the screw rotating shaft 36, and is rotationally driven by the motor 30. The condensed sludge is guided from one end of the cylindrical body 31 to the other end while being compressed by the rotation of the helical screw 37.
[0011]
The sludge reflux path 5 is provided for refluxing the concentrated sludge from the concentrator 3 to the agglomeration reaction tank 2 through the reflux outlet 38.
According to the sludge concentrating apparatus 1 configured as described above, the raw sludge supplied from the raw mud supply pipe 22 to the reaction layer 21 and the flocculant supplied from the flocculant supply pipe 23 are driven by the rotary blades 26a and 26b. With stirring. At this time, the raw sludge and the flocculant are uniformly mixed and flow to the upper part of the agglomeration reaction layer 21 while forming the agglomeration sludge with the generation of the agglomeration flocs by the agglomeration reaction.
[0012]
The agglomerated sludge that has reached the upper part of the reaction tank 21 is supplied to the upper part of the concentrator 3 (cylindrical body 31) through the sludge supply path 4. Then, the coagulated sludge is transferred toward the lower portion of the cylindrical body 31 while being compressed by the helical screw 35 rotating inside the cylindrical body 31. In this process, the liquid component contained in the coagulated sludge is separated through the filtration filter 34 and continuously discharged to the envelope 32 side. Then, the concentration of the coagulated sludge proceeds with the separation of the liquid component. In addition, the liquid component separated into the envelope 32 is taken out to the outside from the separation liquid discharge port 39 below. The balance between the amount of the separated liquid remaining in the envelope 32 and the amount taken out from the separated liquid discharge port 39 is adjusted by the flow meter 40 and the valve 41. By maintaining the balance of the amount of the separation liquid, a differential pressure corresponding to the amount of the separation liquid to be taken out is generated on the filtration surface, and there is no blockage of the filtration surface and SS leakage, and the separation liquid can be filtered smoothly.
[0013]
On the other hand, the concentrated sludge is transported through the cylindrical body 31 and then refluxed to the lower part of the reaction tank 21 through the sludge ring passage 5. At this time, in the reaction tank 21, in addition to the raw sludge supplied from the raw mud supply pipe 22 at the bottom and the flocculant supplied from the flocculant supply pipe 23, the refluxed concentrated sludge is mixed. The refluxed concentrated sludge is released from the concentration in the reaction tank 21, becomes a form of agglomerated floc, and flows in the reaction tank 21. Such agglomeration floc is mixed with the raw sludge and the aggregating agent, and the agglomeration reaction proceeds. During this time, the particle size is larger, and the density and mechanical strength are larger.
[0014]
In this way, by repeating the aggregation, concentration, and aggregation of sludge, the growth of the particle size of the aggregated flocs and the increase in density and mechanical strength are promoted, and the concentration of sludge proceeds.
Table 1 shows the sludge treatment results of the apparatus combining the sludge concentrating apparatus shown in FIG. 1, the conventional granulating and concentrating apparatus, and the coagulation tank and the double cylindrical concentrating apparatus.
[0015]
[Table 1]

[0016]
The processing conditions in Table 1 are as follows.
Slag mixed raw sludge with a sludge concentration of 1.5% (mass%) as raw mud was supplied to the agglomeration reaction tank at a supply rate of 10 m ³ / hour, and agglomeration treatment and concentration treatment were performed. The used flocculants are polyferric sulfate as an inorganic flocculant and amphoteric polymer flocculants as an organic flocculant.
[0017]
The concentration of the inorganic flocculant (or polymer flocculant) in Table 1 is per unit volume of solid components determined from the sludge concentration, supply amount of inorganic sewage mixed sludge, concentration of inorganic flocculant, polymer flocculant, and supply amount. Represents the ratio of the total mass of solid components and the like in the inorganic flocculant (or polymer flocculant) to the total mass (Total Solid (TS)). Therefore, the display of this concentration was (mass% / TS).
[0018]
The concentrated sludge concentration is a concentration (mass%) in the concentrated sludge such as sludge solid components after concentration.
The SS (suspended substance) recovery rate represents the ratio of the total amount of SS in the concentrated sludge recovered after the sludge concentration to the total amount of SS in the sewage mixed raw sludge to be input.
The evaluation of the dewaterability of the concentrated sludge is a relative evaluation, where ◎ indicates very good and ○ indicates good.
[0019]
From Table 1, the sludge concentration apparatus according to the embodiment of the present invention achieves a better concentration than the conventional sludge concentration apparatus, that is, the higher concentration performance with the addition of less coagulant than the conventional sludge concentration apparatus. It was proved that less sludge loss can be achieved in the sludge flocculation and concentration process. Specifically, Table 1 shows the following features of the embodiment of the present invention. First, even if the concentration of the polymer flocculant in the embodiment of the present invention is set to 4/5 (0.8% / TS) of the concentration in the conventional apparatus, the concentrated sludge concentration is 5%. This is an increase of 25 to 66% as compared with the conventional apparatus. Secondly, the SS recovery rate increases by 2 to 4% compared with the conventional apparatus to 99%. Thirdly, by obtaining the above-mentioned first and second characteristics, the dewaterability of sludge according to the embodiment of the present invention is equivalent to “very good” compared to “good” relative evaluation of the conventional apparatus. To do.
[0020]
The present invention is not limited to the above-described embodiment. The sludge concentrator of the present invention is not limited to the concentrator exemplified in the embodiment, and any sludge concentrator can be used for sludge concentration, such as a granulation concentrator, a wedge wire type screen, a drum type screen, etc. It can be used with
Although the sludge discharge channel of the present invention is arranged on the wall surface near the upper end of the coagulation reaction tank in the embodiment, it may be arranged in any part of the concentrator, the sludge supply channel, and the sludge reflux channel.
[0021]
Furthermore, although the sludge concentrating apparatus of the present invention includes one agglomeration reaction tank and one concentrator in the embodiment, it may include a plurality of agglomeration reaction tanks and concentrators, and these arrays may be arranged in series or in parallel. Good.
[0022]
【The invention's effect】
The sludge concentrating apparatus of the present invention recirculates sludge between the flocculation reaction tank and the concentrator and repeats flocculation and concentration, so that the particle size of the flocculated floc can be easily increased, and the density and mechanical strength thereof are increased. Can be increased. As a result, it is possible to improve the degree of concentration of concentrated sludge. Moreover, even if the addition rate of the polymer flocculant is lowered, the SS recovery rate can be increased, and high efficiency of sludge concentration can be achieved. Furthermore, there is the convenience that the sludge concentrator of the present invention can be easily installed even if any conventional existing concentrator is used or diverted.
[0023]
Therefore, this sludge concentrator can further reduce the volume of sludge in coagulation / concentration of sludge such as sewage, human waste, wastewater, etc., and contribute to ease of handling such as sludge dewatering and transfer. Costs can be reduced and existing conventional concentrators can be used effectively.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a sludge concentration apparatus according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sludge concentrator 2 Aggregation reaction layer 3 Concentrator 4 Sludge supply path 5 Sludge reflux path 22 Raw mud supply pipe 23 Coagulant supply pipe 24 Agitation means 33 Pressure feed means 35 Filtration filter 37 Spiral screw

Claims (3)

A flocculation reaction tank for reacting sludge with a flocculant to produce agglomerated sludge;
A concentrator that concentrates the coagulated sludge extracted from the coagulation reaction tank to form a concentrated sludge;
A sludge supply path for supplying aggregated sludge from the aggregation reaction tank to the concentrator;
A sludge concentrating apparatus comprising a sludge circulation channel for circulating the concentrated sludge formed by the concentrator to the agglomeration reaction tank ,
The concentrator includes a filter on the peripheral wall, and a cylindrical body into which the coagulated sludge extracted from the coagulation reaction tank is introduced from one end thereof,
A spiral screw that is coaxially provided inside the cylindrical body and is driven to rotate, and guides the aggregated sludge to the other end while compressing the sludge,
A sludge concentrating device, comprising: an envelope provided so as to cover the cylindrical body and collecting the separated liquid separated from the agglomerated sludge through the filtration filter and discharging the separated liquid to the outside .   The sludge concentrating device according to claim 1, wherein the agglomeration reaction tank guides the agglomerated sludge generated by reacting the sludge introduced from the lower part with the aggregating agent to the upper part. The sludge circulation system that circulates the coagulated sludge between the coagulation reaction tank and the concentrator is provided with a sludge discharge passage that branches from the sludge circulation system and discharges the coagulated sludge to the outside. The sludge concentration apparatus of Claim 1 or 2 .

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