JP2739320B2 - Polluted water flocculation equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for coagulating a suspended substance from a suspension containing a suspended substance generated in a wastewater treatment step of a water supply system, a sewer system, various manufacturing industries, a civil engineering construction industry, etc. The present invention also relates to a device for granulating and separating particulate solids and overflowing a supernatant liquid having a low suspended substance concentration.

Since the suspension generated in the wastewater treatment process contains a large amount of water and is in a fluid state, in order to incinerate or dispose of these suspended solids, first of all, the suspension must be agglomerated, concentrated, Dehydration treatment was required. Conventionally, these treatment methods simply involve adding an inorganic and / or organic coagulant to the suspension in a coagulation tank or a coagulation trough and stirring to coagulate and flocculate the suspended substance. The method of transferring to a concentrator and a dehydrator has become the mainstream. Also,
As an improved method, an apparatus has been developed which separates suspended substances in a suspension into pellet-like solid particles having good dehydration properties and easy handling (Japanese Utility Model Publication No. 46-26272 and Japanese Utility Model Publication No. 54-30223). Reference).

However, even in these improved apparatuses, the coagulation liquid is not separated from the coagulated solid matter and the coagulated separation liquid at all. In addition, since the coagulated solids are not classified based on particle diameter and density, a state in which a sufficiently granulated fine dense solid and an initial coagulated solid whose coagulation and granulation are still insufficient is mixed. It was not possible to obtain sufficient circulation and flow effects because of overflow.

The present inventor has conducted various studies to improve the deficiencies of these conventional devices, and as a result, under the ideal flocculation conditions, mixed the suspension material in the liquid with the flocculant, aggregated, and granulated. Selectively classify finer, higher particle strength, lower inclusion water particulate solids to drain from the bottom of the device, while allowing the supernatant with low suspended solids to overflow from the top of the device The device was completed.

That is, the present invention provides an inner cylinder having a lower part opened inside a tank body having a conical bottom portion, an impeller for generating an ascending circulating flow in the inner cylinder, and a plurality of upper edges of the inner cylinder. A notch is provided at a location, a guide plate is screwed in a gap between the inner cylinder and the tank body from the left and right side surfaces of the notch, and the tank body and the inner cylinder are penetrated so as to be located near the lower end of the inner cylinder. A suspension supply pipe is provided, and an injection pipe for the flocculant solution is provided similarly to the suspension supply pipe,
The present invention relates to an apparatus for aggregating polluted water, characterized in that a drain pipe is provided at a lower part of a tank body through a drain valve, while an overflow pipe is provided at an upper part of the tank body.

 Next, the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, reference numeral 1 denotes a tank main body, which has a cylindrical shape having a conical bottom, a polygonal shape, an elliptical cylindrical shape, or the like. Reference numeral 2 denotes an inner cylinder, which has a hollow cylindrical or polygonal cylindrical shape, and whose upper end is suspended from the support frame 16 above the tank or supported by the inner wall of the tank so that the upper end thereof is slightly higher than the liquid level in the tank. The outer diameter is preferably about 1/4 to 3/4 of the outer diameter of the tank body. The lower end is located near the height of the joining line between the cylindrical portion and the conical portion of the tank body, and the bottom surface is open.

A plurality of cutouts 3 are provided at the upper edge of the inner cylinder 2 (only one cutout is shown in the drawing). Reference numeral 4 denotes an axial impeller, which is provided so as to be rotated via a shaft 14 by a driving device 15 composed of a variable speed reduction motor mounted on a support frame 16 at the upper part of the tank body 1.

5A and 5B are a set of guide plates for the swirling flow, the same number of sets as the cutouts 3, in a space formed inside the tank body 1 and outside the inner cylinder 2, located on both side surfaces of the cutouts 3, It is provided vertically from the upper end of the inner cylinder 3 to slightly below the lower end of the notch 3, and is inclined at an angle of about 30 to 70 degrees with respect to the perpendicular from there, while spirally winding the outside of the inner cylinder 2. Descend, and 5A and 5B
Is preferably 1/5 to 4/5 above the height of the inner cylinder 2. Note that the inclination angles and lengths of the guide plates 5A and 5B are not limited to the numerical values described above. As a result, the portion between the tank body 1 and the inner cylinder 2 is divided by a plurality of sets of guide plates 5A and 5B such that a plurality of inner zones M and a plurality of outer zones N of the spiral rectangular cylinder are alternately located. Is done.

Reference numeral 6 is a suspension supply pipe, and reference numeral 7 is a coagulant solution injection pipe. Reference numeral 8 denotes an overflow pipe for the supernatant, which is connected to the N zone and has the same number as the number of the cutouts 3.
Is provided with an overflow valve 9 which opens and closes. Reference numeral 10 denotes a discharge pipe provided with a discharge valve 11 which is opened and closed by a liquid level controller 13.

 Next, embodiments of the present invention will be described.

The suspension containing the suspended substance is supplied from the supply pipe 6 to the lower portion inside the inner cylinder 2, and at the same time, an appropriate amount of the coagulant solution is similarly injected from the injection pipe 7. On the other hand, the inside of the tank main body is already filled with the mixed liquid of the suspension and the coagulant solution, and the inside of the inner cylinder 2 is raised by the impeller 4, and the square, spiral rectangular pipe M is lowered from the notch 3. And rises again through the lower end of the inner cylinder. The newly supplied suspension and the coagulant solution immediately flow into the circulating flow, and are appropriately stirred and mixed by the impeller 4, resulting in a uniform circulating flow and coagulation starts. In this circulating liquid, small-sized solid particles that are all cohering and growing are present, so that coagulation easily starts around the solid particles.

This liquid flows out of the notch 3 and flows down while rotating in the rectangular cylinder zone M. During this time, the coagulated solids in the circulating flow form collision polymerization between the particles, rolling motion of the particles on the channel wall,
Under the influence of a complex external force such as a centrifugal force due to the swirling flow, it gradually granulates and grows into a large, fine, aggregated solid having a high specific gravity. The agglomerated solids reach the outside of the lower layer of the zone M, and the initial agglomerated solids, the small-sized agglomerated solids, the agglomerated separation liquid, etc., which are insufficiently agglomerated, move to the inner side of the upper layer of the zone M while being transferred to the tank body. Reach the lower cone.

The zone N is filled with a part of the liquid flowing through the zone M. However, in zone N, there is almost no flow velocity of the liquid,
Further, since the guide plates 5A and 5B have the effect of the sedimentation inclined plate, the sedimentation of the solid is promoted, and the supernatant can be easily obtained. Since the liquid level of this tank is normally set slightly higher than the upper end of the overflow pipe 8 by the liquid level controller 13, the overflow valve 9 is opened intermittently using the timer 12 to remove only the supernatant liquid. Can overflow. On the other hand, of the circulating fluid that has reached the conical portion of the tank body, the large, minute, dense and high specific gravity coagulated solid that has swirled down the zone M, swirls down along the wall of the conical portion, and is stored at the lower portion of the conical portion. Then, the liquid is discharged to the next step through a discharge pipe 10 by a discharge valve 11 which is opened and closed by a liquid level controller.
In addition, the circulating liquid containing insufficiently coagulated solids and the like, which has swirled down the inside of the zone M, is sucked into the inner cylinder 2 by the ascending flow by the impeller 4 and becomes a recirculating liquid.

As described above, the present invention rotates the axial flow impeller having a small rotational peripheral speed inside the inner cylinder provided in the tank main body to give rise while minimizing the destruction of the flocculated flocs in the circulating fluid, and A spiral guide plate is provided on the outside of the inner cylinder to provide a long swirling flow, and further, particles are grown and classified only with high specific gravity, and discharged from the lower part. The low agglomerated solids can be recycled to measure the agglomeration granulation growth. Also, the flocculation and separation liquid generated during the flocculation and granulation can be concentrated by condensing the granulation liquid by overflowing as a supernatant liquid. As a result, the granulation conditions of the aggregated solid matter become ideal, and the dewatering property in the subsequent dehydration step can be greatly improved.

[Brief description of the drawings]

FIG. 1 shows a side sectional view of the device of the present invention, and FIG.
FIG. 2 shows a sectional view taken along line AA ′ of FIG.

Claims (1)

(57) [Claims] 1. An inner cylinder having a lower portion opened inside a tank body having a conical bottom portion, an impeller for generating an upward circulating flow is provided in the inner cylinder, and a plurality of upper edges of the inner cylinder are provided. A notch is provided at a location, a guide plate is screwed in a gap between the inner cylinder and the tank body from the left and right side surfaces of the notch, and the tank body and the inner cylinder are penetrated so as to be located near the lower end of the inner cylinder. A suspension supply pipe is provided, a coagulant solution injection pipe is provided in the same manner as the suspension supply pipe, and a discharge pipe is provided at the lower end of the tank body through a drain valve, while an upper part of the tank body is provided. Is an apparatus for aggregating polluted water, which is provided with an overflow pipe.