JP6218036B2 - Coagulation reactor - Google Patents

Description

  The present invention relates to wastewater treatment technology. More specifically, the present invention relates to a flocculation reaction tank used in a flocculation process of wastewater treatment using a polymer flocculant.

  In wastewater treatment using a polymer flocculant, as shown in FIG. 6, the wastewater is sent from the raw water tank to the agglomeration reaction tank, a floc is formed with the flocculant, and then sent to the dehydrator. In general, however, recent dehydrators tend to achieve energy savings in apparatus power by increasing the filter pore diameter of the filter medium. In a dehydrator with a coarse filter medium, the combined use of cationic and anionic polymer flocculants produces flocs that are coarse, strong, and have good dehydrating properties, thereby drawing out the performance of the dehydrator. It becomes the point for. Therefore, the type and addition amount of the flocculant charged into the flocculent reaction tank and the stirring speed for stirring the flocculant and the raw water are important factors. In addition, the stirring time of the flocculant and the raw water in the flocculation reaction tank is extremely important for producing an appropriate floc. This is because the agitation time is proportional to the time required for the agglutination reaction. If the agglomeration reaction time is short, the generation of floc is insufficient, and if the agglomeration reaction time is too long, the generated floc is destroyed by agitation. This is because there are cases.

  As disclosed in Patent Document 1, since the volume of the agglomeration reaction tank is constant in the prior art agglomeration reaction tank, it is possible to control the agglomeration time in the agglomeration reaction tank by increasing / decreasing the input rate of waste water. However, in this case, it is difficult to control the optimal wastewater treatment time that matches the capacity of the dehydrator. However, in order to shorten the operation time for energy saving of the apparatus power, wastewater treatment in accordance with the capacity of the dehydrator is necessary, and an optimal and inexpensive method for quantitatively supplying wastewater to the dehydrator has been desired.

JP 2001-198599 A

  An object of the present invention is to provide an agglomeration reaction tank for quantitatively supplying wastewater from the agglomeration reaction tank to the dehydrator in accordance with the treatment capacity of the dehydrator in the agglomeration reaction tank for wastewater treatment.

In order to achieve the above object, the present invention is a flocculation reaction tank used for wastewater treatment, a stirring means for stirring the wastewater and the flocculant, and a wall surface of the flocculation reaction tank for discharging the wastewater after the reaction. It has a fixed overflow port and a variable volume container placed in the coagulation reaction tank for making the wastewater treatment volume variable, and the variable volume container is inclined partly or entirely of the bottom surface of the rectangular parallelepiped. In addition, the rectangular parallelepiped has an open top surface and is arranged on both sides of the stirring means provided in the center of the agglomeration reaction tank so that the inclined surfaces of the bottom surface of the variable volume container face each other. In the agglomeration reaction tank, a guide for assisting the vertical movement of the container is provided on the wall surface of the agglomeration reaction tank.

In the present invention configured as described above, it is possible to change the wastewater treatment volume in the agglomeration reaction tank by changing the amount of liquid input into the variable volume container. For this reason, the residence time of the waste water in the agglomeration reaction tank can be changed if the rate of waste water input into the agglomeration reaction tank is constant. That is, the optimum wastewater treatment time can be controlled by a simple method in which the amount of liquid input to the variable volume container is changed according to the capacity of the dehydrator. Moreover, since the wastewater treatment volume in the coagulation reaction tank can be changed by such a simple method, there is a merit in terms of cost. Furthermore, since the overflow port of the agglomeration reaction tank is fixed at one place on the wall surface, the height from the overflow port to the dehydrator can be fixed. For example, the dehydrator generated when the overflow port is movable There is no need to cause the destruction of flocs generated in the agglomeration reaction tank due to the magnitude of the drop at the time of charging. In addition, since a part of the bottom surface of the rectangular parallelepiped or the entire surface is inclined creates a flow that pushes up the aggregation floc, it is easy to collect the aggregation floc up to the center of the aggregation reaction tank having the overflow port.

  In the present invention, the bottom surface of the agglomeration reaction tank is substantially square, and the ratio (height / width) between the height from the bottom surface of the agglomeration reaction tank to the overflow port and the width of the agglomeration reaction tank is 0.2-2. The agglomeration reaction tank is zero.

  In the present invention configured as described above, flocs generated by the polymer flocculant are coarsened so that they tend to settle in the agglomeration reaction tank, but the flocs overflow even if the agitation is slow because the agglomeration reaction tank is shallow. This makes it possible to minimize the amount of flocculant added.

  In the present invention, an indication of the wastewater treatment volume in the agglomeration reaction tank is provided on the side of the volume variable container of the agglomeration reaction tank.

  In the present invention configured as described above, the volume displaced by the variable volume container can be obtained at a glance. From the actual volume of the aggregation tank, the volume of the aggregation reaction tank is subtracted from the volume of the volume variable container indicated by the water level. It becomes possible to know the volume.

  According to the agglomeration reaction tank of the present invention, it is possible to provide an agglomeration reaction tank for quantitatively supplying wastewater from the agglomeration reaction tank to the dehydrator according to the processing capacity of the dehydrator.

It is a top view of the aggregation reaction tank in the present invention. It is AA sectional drawing concerning FIG. 1 (at the time of a process amount intermediate | middle). It is AA sectional drawing concerning FIG. 1 (When processing amount is the minimum). It is a partial permeation | transmission perspective view of the agglomeration reaction tank in this invention (at the time of processing amount minimum). It is the figure which showed the example of the shape of the variable volume container in this invention. It is the figure which showed the general aggregation filtration process.

  The agglomeration reaction tank of the present invention will be described with reference to FIGS. The agglomeration reaction tank 1 has a stirring means 5 for agitating the waste water and the aggregating agent, an overflow port 3 fixed to the wall surface of the agglomeration reaction tank in order to discharge the waste water after the reaction, and a waste water treatment volume. It is comprised with the variable volume container 2 arrange | positioned in the aggregation reaction tank for making it variable.

  The agglomeration reaction tank 1 may be a rectangular parallelepiped or a cylindrical body, but is preferably a rectangular parallelepiped from the viewpoint of production cost and the like, and more preferably a rectangular parallelepiped having a bottom surface of substantially square in terms of stirring efficiency.

  In FIG. 1 to FIG. 4, two variable volume containers 2 are mounted in the agglutination reaction tank, but one or more than three may be mounted in the agglomeration reaction tank. However, in order to perform a uniform agglomeration reaction in terms of cost, two variable volume containers are preferable, and it is preferable that they are arranged on both sides of the stirring means 5 in terms of performing a more uniform agglomeration reaction.

  Further, the variable volume container 2 has a shape in which the entire bottom surface of the rectangular parallelepiped is inclined as shown in FIG. 5A and the top surface of the rectangular parallelepiped is opened, or the bottom surface of the rectangular parallelepiped as shown in FIG. A shape in which a part of the rectangular parallelepiped is inclined and the upper surface of the rectangular parallelepiped is opened is preferable. Since the upper surface of the variable volume container is open, a necessary amount of water is poured from here. Water injection / drainage into the variable volume container can be performed by a pump or the like provided outside.

  FIG. 2 is a cross-sectional view in which the amount of wastewater in the agglomeration reaction tank is about halfway between the maximum amount and the minimum amount. In order to change the wastewater treatment amount shown in FIG. 3 to the minimum treatment amount from this state, the wastewater treatment amount is obtained by pouring water into the variable volume container until the bottom surface of the variable volume container contacts the bottom surface of the agglomeration reaction tank. Becomes the minimum processing amount. In order to maximize the amount of wastewater treated in the coagulation reaction tank, it can be performed by removing the variable volume container from the coagulation reaction tank. In addition, when the intermediate treatment amount of the wastewater treatment amount is 100, the size of the variable volume container is determined so that the minimum treatment amount is about 50 to the maximum treatment amount 200. Is necessary.

  The variable volume container 2 is disposed on both sides of the stirring means 5 provided in the center of the agglomeration reaction tank so that the inclined surfaces of the bottom surface of the variable volume container face each other. This is preferable because the inclined surface of the part or the whole creates a flow that pushes up the agglomeration floc, making it easy to collect the agglomeration floc up to the central part of the agglomeration reaction tank having the overflow port.

  It is preferable that a guide 4 for supporting the movement of the variable volume container is provided on the wall surface of the aggregation reaction tank. The guide 4 serves as a support when the variable volume container moves up and down, and also serves to prevent contact between the variable volume container and the stirring means. In FIG. 1 to FIG. 4, four guides 4 are provided in the agglomeration reaction tank, but this is not a limitation, and more guides may be provided. 1 to 4, the guide extends from the upper end of the agglomeration reaction tank to the lower center, but there is no problem even if the guide extends to the lower end of the agglomeration reaction tank. Further, the shape of the guide is not limited to a prism, and may be a shape such as a cylinder.

  The aggregation reaction tank 1 preferably has a ratio (height / width) of the height from the bottom surface to the overflow port 3 and the width of the aggregation reaction tank of 0.2 to 2.0. In addition, when the bottom face of the agglomeration reaction tank is rectangular, the ratio is the longest side of the four sides constituting the rectangle. Within this ratio range, flocs generated by the polymer flocculant coarsen and easily settle in the agglomeration reaction tank, but the flocs can overflow even with slow stirring because the agglomeration reaction tank is shallow. It becomes possible to minimize the amount of the flocculant added. When the ratio between the height and the width is less than 0.2, the installation area of the agglomeration reaction tank is increased, and the agglomeration reaction in the agglomeration reaction tank is not preferable. Also, if the ratio of height to width is larger than 2.0, it becomes difficult for the floc to settle because it settles in the agglomeration reaction tank, and the floc interferes with the agglomeration reaction in the agglomeration reaction tank. Therefore, it is not preferable.

  The stirring means 5 may be comprised by the stirring blade 6 and the stirring motor 7 like FIGS. 1-4, or may be comprised by things like a circulation pump.

  A scale 8 is preferably displayed inside the variable volume container 2 as shown in FIG. It is necessary to add and discharge water in the variable volume container to make the required volume of wastewater treatment in the coagulation reaction tank. If a scale is displayed in the variable volume container, visually check the scale. It is convenient to work while.

  In using the agglomeration reaction tank having the above-described configuration, it is necessary to grasp in advance the optimum addition amount of the aggregating agent and the agglomeration reaction time. Therefore, as a preliminary test, waste water and a flocculant are introduced into a separately prepared beaker, and an optimum flocculant addition amount and agglomeration reaction time are calculated according to the degree of aggregation. Next, from the volume per day that requires wastewater treatment, the stock solution feeding speed to be supplied to the coagulation reaction tank is obtained, and the optimum coagulation reaction time obtained in the preliminary test, that is, the residence time in the coagulation reaction tank is obtained. Then, the required volume of the agglomeration reaction tank is calculated, and water is poured into the variable volume container mounted in the agglomeration reaction tank so as to be the required volume of the agglomeration reaction tank.

  After the preparation for operation is completed, the actual operation of wastewater treatment is started. Waste water is supplied from the upper part of the coagulation reaction tank, and at the same time, the polymer flocculant is added in the vicinity of the waste water supply point. The uniform agglomeration reaction proceeds by the stirring means, the waste water is agglomerated with the minimum amount of flocculant added, and the floc coarsened agglomerated liquid is continuously supplied to the subsequent dehydrator via the overflow port. It will be.

  When the front and depth of the agglomeration reaction tank are 750 mm in outer size (inner dimension 734 mm) and the overflow port height is 300 mm, the maximum volume of the agglomeration reaction tank is about 161.6 L. If the volume from the lower end of the variable volume container installed in the agglomeration reaction tank to the height of the overflow port is about 57.7L, the total volume of the two variable volume containers is about 115.3L. The minimum volume of the agglomeration reaction tank is about 46.3 L obtained by subtracting about 115.3 L of two variable volume containers from the maximum volume of the aggregation reaction tank of about 161.6 L. Assuming that the amount of wastewater supplied from the raw water tank to the coagulation reaction tank is 500 L / hr (8.33 L / min), the residence time at the minimum volume of the coagulation reaction tank is about 5.6 minutes, The residence time is about 19.4 minutes.

  In the case of this agglomeration reaction tank, the waste liquid treatment volume in the agglomeration reaction tank is variable from about 46.3L to about 161.6L depending on the amount of water injected into the variable volume container, and this waste liquid treatment volume and the waste liquid retention time in the agglomeration reaction tank Is proportional, so the residence time can vary from about 5.6 minutes to about 19.4 minutes.

DESCRIPTION OF SYMBOLS 1 Coagulation reaction tank 2 Volume variable container 3 Overflow port 4 Guide 5 Agitation means 6 Agitation blade 7 Agitation motor 8 Scale 11 Aggregation reaction tank 12 Raw water tank 13 Coagulant tank 14 Dehydrator

Claims (3)

An agglomeration reaction tank used for wastewater treatment, an agitation means for agitating wastewater and an aggregating agent, an overflow port fixed to the wall of the agglomeration reaction tank to discharge the wastewater after reaction, and wastewater A variable volume container disposed in an agglomeration reaction tank for making the processing volume variable , wherein the variable volume container has a part or the whole of the bottom face of the rectangular parallelepiped inclined and the top face of the rectangular parallelepiped is opened. It is shaped and arranged on both sides of the stirring means provided in the central part of the agglomeration reaction tank so that the inclined surfaces of the bottom surface of the variable volume container face each other, and assists the vertical movement of the variable volume container An agglomeration reaction tank in which a guide is provided on the wall surface of the agglomeration reaction tank.   The bottom surface of the aggregation reaction tank is substantially square, and the ratio (height / width) of the height from the bottom surface of the aggregation reaction tank to the overflow port and the width of the aggregation reaction tank is 0.2-2. The agglomeration reaction tank according to claim 1, which is zero. The aggregation reaction tank according to claim 1 , wherein a display of a wastewater treatment volume in the aggregation reaction tank is provided on a side surface of the variable volume container.

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