JP4166624B2 - Method and apparatus for supplying flocculant in sludge dewatering machine - Google Patents

Description

【００１２】
汚泥供給量を固定し、汚泥濃度の変動に対応して高分子凝集剤供給量を可変とする。つまり、汚泥濃度が低いときは高分子凝集剤供給量が少くなり、汚泥濃度が高いときは高分子凝集剤供給量が多くなるように、汚泥供給量は変動することなく汚泥濃度の変動に対し高分子凝集剤供給量を可変として、前記高分子凝集剤供給量を汚泥固形物供給量（汚泥供給量×汚泥濃度）で割った比率である高分子凝集剤供給率を一定にしようとする制御法である。
【００１３】
汚泥中継槽３内へ予め無機凝集剤を注入する場合は、無機凝集剤の毎分当りの供給量は下記の数式２で求められる。
【００１４】
【数２】

【００１５】
【発明の効果】
本発明によれば、制御系統が複雑化せず製造コストおよびランニングコストを押し上げることがなく、また、凝集混和槽１０と汚泥貯留槽２との中間に位置した汚泥中継槽３内において他の制御の干渉を受けない態様で濃度センサ８が設けられており、且つ、汚泥中継槽３を小型に構成することができて汚泥の均一化が迅速に行われるため、常時汚泥中継槽３に汚泥を流入させた場合や、汚泥脱水機１から発生するリーク汚泥を直接汚泥中継槽３で受けた場合でも、汚泥貯留槽２に比べて急激な濃度変化が起り難いので、汚泥中継槽３で発生する濃度変化にも十分対応できて凝集不良を生じることなく、凝集剤供給量を適正に調整して汚泥脱水機１本来の性能を十分に発揮させることができるという利点がある。
【図面の簡単な説明】
【図１】本発明装置の構成図である。
【図２】本発明方法による制御のフローチャートである。
【符号の説明】
１ 汚泥脱水機
２ 汚泥貯留槽
３ 汚泥中継槽
４ 汚泥移送ポンプ
６ 無機凝集剤注入ポンプ
７ 汚泥攪拌ポンプ
８ 濃度センサ
９ 汚泥供給ポンプ
１０ 凝集混和槽
１１ 流量計
１２ 高分子凝集剤注入ポンプ
１４ 攪拌機
１５ 制御盤
１６ 演算部
１７Ａ 高分子凝集剤注入ポンプの回転数を司るインバータ
１７Ｂ 無機凝集剤注入ポンプの回転数を司るインバータ
１８Ｐ ドレン管
１８Ｖ ドレン弁[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for supplying a flocculant in a sludge dehydrator.
[0002]
[Prior art]
Chemicals in the sludge dewatering process, in which the amount of sludge that flows through the chemical pump and chemical flow meter is made variable, and the moisture content of the dewatered cake is kept constant by quantifying the chemicals such as flocculants added to the sludge. Injection methods and devices are known (see, for example, Patent Document 1). In addition, the sludge concentration of the raw material sludge is measured with a concentration sensor, the supply amount of the flocculant solution and the operation time of the chemical pump for the flocculant solution so that the sludge solid content amount and the solid content amount ratio of the flocculant solution are determined. A method and an apparatus for adjusting the moisture content of sludge are known in which the flocculant solution is supplied to the raw sludge based on the operation time and mixing and dewatering are automatically performed (see, for example, Patent Document 2). ).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-10199 (Summary, FIG. 1, FIG. 7-9)
[Patent Document 2]
JP 2002-361299 A (summary, Fig. 1-3)
[0004]
[Problems to be solved by the invention]
However, in the case of Patent Document 1, since a chemical flow meter is used on the flocculant supply side and the dehydrated filtrate is measured and controlled by the photometric device, the control system becomes complicated and increases the manufacturing cost and running cost. In addition, the inflow adjustment of sludge cannot follow the rapid concentration change of the sludge to be dehydrated, resulting in a coagulation failure and the original performance of the dehydrator cannot be exhibited. Moreover, in the method and apparatus of patent document 2, in the sludge storage tank in which the sludge used as the object of dehydration is accommodated, it is necessary to enlarge the capacity | capacitance in a tank, Therefore, the density | concentration of the sludge in a tank is uneven, and a measuring point The density value varies greatly from one to another. Therefore, in the method in which sludge is sent directly to the mixing tank closest to the dehydrator, a concentration meter is installed in the mixing tank closest to the dehydrator. There is a drawback that the amount cannot follow the change, resulting in poor aggregation. Then, every time the sludge concentration fluctuates, agglomeration failure frequently occurs, and the dewatering capacity decreases as in the case of Patent Document 1, and the original performance of the dewatering machine cannot be exhibited.
[0005]
The object of the present invention is that the control system is not complicated and does not increase the manufacturing cost and running cost, and the supply amount of sludge solids in the sludge dewatering machine is a drastic change in the concentration of sludge to be dewatered. It is an object of the present invention to provide a method and an apparatus for supplying a flocculant in a sludge dewatering machine, which can cope with the above and does not cause a coagulation failure, and can fully exhibit the original performance of the dewatering machine.
[0006]
[Means for solving problems]
In the method for supplying a flocculant in the sludge dewatering machine according to claim 1 of the present invention, the sludge is transferred from the lower part in the sludge storage tank in which the sludge to be dewatered is stored, and the sludge relay tank is used. The amount of sludge that is temporarily stored in the sludge relay tank and measured by the concentration sensor in the sludge relay tank is supplied by the concentration sensor, and sludge is supplied from the sludge relay tank to the coagulation mixing tank by the sludge supply pump. Is measured with a flow meter, and the measured sludge concentration and supply amount are analyzed by the calculation unit of the control panel and replaced with the frequency to fix the sludge supply amount and to control the rotation speed of the polymer flocculant injection pump. By increasing or decreasing the amount of polymer flocculant supplied to the flocculent mixing tank, the polymer flocculant supply rate is kept constant. To supply. Further, in the method for supplying a flocculant in the sludge dewatering machine according to claim 2 of the present invention, on the premise of the invention according to claim 1, sludge supplied into the coagulation mixing tank is preliminarily inorganic in the sludge relay tank. An inorganic flocculant is injected by a flocculant injection pump to form a colloidal aggregate state.
[0007]
In the flocculant supply device in the sludge dewatering machine according to claim 3 according to the present invention, in the sludge dewatering machine for separating sludge into filtrate and dewatered cake, a sludge storage tank containing sludge to be dewatered; , Sludge relay tank for temporarily storing the sludge supplied to the sludge dewatering machine, sludge transfer pump for transferring the sludge in the sludge storage tank into the sludge relay tank, and leaked sludge accumulated at the bottom of the sludge dewatering machine A drain pipe for draining water into the sludge relay tank, a drain valve for opening and closing the drain pipe, a stirring pump for equalizing the sludge concentration in the sludge relay tank, and uniform in the sludge relay tank A concentration sensor for measuring the concentration of the activated sludge, a sludge supply pump for supplying sludge from the sludge relay tank to the agglomeration and mixing tank, and a sludge supply amount supplied by the sludge supply pump. measurement A coagulation / mixing tank for containing the sludge supplied from the sludge relay tank to the sludge dewatering machine and mixing the polymer flocculant, and injecting the polymer flocculant into the coagulation / mixing tank A polymer flocculant injection pump for mixing, a stirrer for mixing and stirring the polymer flocculant into sludge in the flocculent mixing tank, and a control panel having a calculation unit for analyzing the measured values by the concentration sensor and the flow meter An inverter that controls the rotational speed of the polymer flocculant injection pump in response to an output signal from the arithmetic unit is provided. In addition, in the flocculant supply device in the sludge dehydrator according to claim 4 of the present invention, an inorganic flocculant injection pump for injecting the inorganic flocculant into the sludge relay tank on the premise of the invention according to claim 3 Was added.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0009]
1 is a sludge dewatering machine for separating sludge into drainage and dewatered cake, 2 is a sludge storage tank containing sludge to be dewatered, 3 is a small sludge for temporarily storing sludge to be supplied to the sludge dewatering machine 1 The relay tank 4 is a sludge transfer pump for transferring the sludge in the sludge storage tank 2 into the sludge relay tank 3, 5 is a screen for removing contaminants, 6 is an inorganic flocculant injection pump, It is used when injecting an inorganic flocculant into the tank 3 to keep the sludge in a colloidal aggregate state. 18P is a drain pipe for draining leaked sludge accumulated at the bottom of the sludge dewatering machine into the sludge relay tank 3, 18V is a drain valve for opening and closing the drain pipe 18P, and 7 is in the sludge relay tank 3. 1 is a concentration sensor for measuring the concentration of the sludge homogenized in the sludge relay tank 3, and 9 is agglomeration and mixing described below from the upper part in the sludge relay tank 3. A sludge supply pump 11 for supplying into the tank 10 is a flow meter for measuring the amount of sludge supplied by the sludge supply pump 9, and is provided in the discharge pipe of the sludge supply pump 9. . 10 is a coagulation / mixing tank for containing sludge supplied from the sludge relay tank 3 to the sludge dewatering machine 1 and mixing the polymer coagulant, and 12 is for injecting the polymer coagulant into the coagulation / mixing tank 10. A polymer flocculant injection pump, 13 is a dissolution unit panel, and 14 is a stirrer for mixing and stirring the polymer flocculant with sludge in the flocculent mixing tank 10. Reference numeral 15 denotes a control panel, which has a calculation unit 16 for calculating the amount of flocculant injected by the polymer flocculant injection pump 12 and the inorganic flocculant injection pump 6 based on the measured values by the concentration sensor 8 and the flow meter 11. ing. An inverter 17A receives the output signal from the calculation unit 16 and controls the rotation speed of the polymer flocculant injection pump 12, and 17B receives an output signal from the calculation unit 16 and controls the rotation speed of the inorganic flocculant injection pump 6. It is.
[0010]
The sludge is transferred from the lower part of the sludge storage tank 2 containing the sludge to be dehydrated by the sludge transfer pump 4 and temporarily stored in the small sludge relay tank 3 (injecting an inorganic flocculant if necessary) Then, the concentration of sludge homogenized by the stirring pump 7 in the sludge relay tank 3 is measured by the concentration sensor 8 and the measured value is sent to the calculation unit 16 of the control panel 15. The amount of sludge supplied from the upper part of the sludge relay tank 3 to the coagulation mixing tank 10 by the sludge supply pump 9 is measured by the flow meter 11, and the measured value is sent to the calculation unit 16 of the control panel 15. The amount of the polymer flocculant supplied to the flocculation mixing tank 10 is analyzed by the unit 16 and replaced with the frequency, and the sludge supply amount is fixed and the rotation speed of the polymer flocculant injection pump 12 is controlled by the inverter 17A. By increasing or decreasing The molecular flocculant supply rate is constant, and the sludge mixed with the polymer flocculant is sequentially supplied to the sludge dehydrator 1 in the flocculent mixing tank 10 by the stirrer 14, but the polymer flocculant is supplied per minute. The amount is calculated by the following formula 1.
[0011]
[Expression 1]

[0012]
The sludge supply amount is fixed, and the polymer flocculant supply amount is variable in response to fluctuations in sludge concentration. That is, when the sludge concentration is low, the polymer flocculant supply amount decreases, and when the sludge concentration is high, the polymer flocculant supply amount increases. Control to make the polymer flocculant supply rate constant, which is the ratio of the polymer flocculant supply amount divided by the sludge solids supply amount (sludge supply amount x sludge concentration) Is the law.
[0013]
When the inorganic flocculant is injected into the sludge relay tank 3 in advance, the supply amount of the inorganic flocculant per minute can be obtained by the following mathematical formula 2.
[0014]
[Expression 2]

[0015]
【The invention's effect】
According to the present invention, the control system is not complicated and does not increase the manufacturing cost and running cost, and other control is performed in the sludge relay tank 3 positioned between the coagulation mixing tank 10 and the sludge storage tank 2. Since the concentration sensor 8 is provided in a manner that does not receive the interference, and the sludge relay tank 3 can be configured in a small size so that the sludge can be uniformly homogenized, the sludge relay tank 3 is always subjected to sludge. Even when it is introduced or when leaked sludge generated from the sludge dewatering machine 1 is directly received by the sludge relay tank 3, it is less likely to cause a rapid concentration change compared to the sludge storage tank 2. There is an advantage that the original performance of the sludge dewatering machine 1 can be sufficiently exhibited by adequately adjusting the supply amount of the coagulant without causing a coagulation defect and sufficiently responding to a change in concentration.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an apparatus according to the present invention.
FIG. 2 is a flowchart of control by the method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sludge dewatering machine 2 Sludge storage tank 3 Sludge relay tank 4 Sludge transfer pump 6 Inorganic flocculant injection pump 7 Sludge stirring pump 8 Concentration sensor 9 Sludge supply pump 10 Agglomeration mixing tank 11 Flowmeter 12 Polymer flocculant injection pump 14 Stirrer 15 Control panel 16 Arithmetic unit 17A Inverter 17B that controls the rotation speed of the polymer flocculant injection pump Inverter 18P that controls the rotation speed of the inorganic flocculant injection pump 18P Drain pipe 18V Drain valve

Claims (4)

The sludge transported from the lower part of the sludge storage tank containing the sludge to be dewatered by the sludge transfer pump, temporarily stored in the sludge relay tank, and the sludge homogenized by the stirring pump in the sludge relay tank Concentration is measured with a concentration sensor, and sludge is supplied from the sludge relay tank to the coagulation mixing tank by a sludge supply pump, and the supply amount is measured with a flow meter. The measured sludge concentration and supply amount are controlled by the control panel. The frequency is analyzed and replaced with the frequency, the sludge supply amount is fixed, and the rotation speed of the polymer flocculant injection pump is controlled to increase or decrease the supply amount of the polymer flocculant supplied into the coagulation mixing tank. The method for supplying a flocculant in a sludge dewatering machine is characterized in that the supply rate of the polymer flocculant is constant and sludge mixed with the polymer flocculant is sequentially supplied to the sludge dewatering machine in the coagulation mixing tank. The sludge supplied into the coagulation mixing tank is preliminarily formed into a colloidal coagulated state by injecting the inorganic coagulant with an inorganic coagulant injection pump in the sludge relay tank. To supply flocculant in sludge dewatering machine. In a sludge dewatering machine for separating sludge into filtered water and dewatered cake, a sludge storage tank containing sludge to be dewatered, a sludge relay tank for temporarily storing sludge supplied to the sludge dewatering machine, and sludge Sludge transfer pump for transferring sludge in the storage tank into the sludge relay tank, drain pipe for draining the sludge accumulated at the bottom of the sludge dewatering machine into the sludge relay tank, and opening and closing the drain pipe A drain valve, a stirring pump for homogenizing the sludge concentration in the sludge relay tank, a concentration sensor for measuring the concentration of the sludge homogenized in the sludge relay tank, and the sludge relay tank The sludge supply pump for supplying sludge to the sludge mixing tank, the flow meter for measuring the amount of sludge supplied by the sludge supply pump, and the sludge supplied from the sludge relay tank to the sludge dehydrator Contain A coagulation mixing tank for mixing the polymer coagulant, a polymer coagulant injection pump for injecting the polymer coagulant into the coagulation mixing tank, and the polymer coagulant into sludge in the coagulation mixing tank. Controls the rotation speed of the polymer flocculant injection pump by receiving an output signal from the agitator for mixing and stirring, a control panel having a calculation unit for analyzing the measurement value by the concentration sensor and the flow meter, and an output signal from the calculation unit An apparatus for supplying a flocculant in a sludge dewatering machine, comprising an inverter. The apparatus for supplying a flocculant in a sludge dewatering machine according to claim 3, further comprising an inorganic flocculant injection pump for injecting the inorganic flocculant into the sludge relay tank.

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