JP2011246916A - Screen for capturing contaminants in sand basin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screen for capturing contaminants in a sand basin that can capture a drift object or floating matter and small stones and gravel regardless of size without causing clogging of the screen.SOLUTION: In a screen that extends from the bottom face in the upstream side end section of a sand basin, upward on the hour's highest water level of the sand basin and that captures contaminants mixed in sewage such as rain water that is about to flow in the sand basin, a mesh at the lower part of the screen is made finer than the one at the upper part of the screen.

Description

  The present invention relates to a screen for removing contaminants from sewage immediately before flowing into a sand basin from an inflow basin in a sewage treatment facility.

  In general, sewage mixed with sewage and rainwater collected from the sewer pipe into the inflow trough flows into the sand basin of the sewage treatment facility from one end, and the sediment is separated by sedimentation in the sand basin. The sewage from which the sediment has been separated flows out to the pump well through a filter installed at the other end of the sand basin, is pumped out by a drain pump installed in the pump well, and is transferred to a final treatment plant. After the sewage inflow to the settling basin continues for a period of time that the amount of earth and sand deposited on the entire bottom of the settling basin reaches a predetermined amount, the sewage inflow to the settling basin is stopped. Sewage discharge continues and when the drainage state where the water level of the pump well is lowered to a predetermined position equal to the upper surface of the weir provided between the sedimentation basin and the pump well, the operation of the drainage pump is stopped and the sedimentation basin The sand collector is activated.

The sand collecting device starts the operation of the water supply pump installed in the pump well following the stoppage of the drainage pump, and supplies the low pressure water of 0.003 to 0.3 Mpa at the maximum from the water supply pump to the bottom of the sand basin. The nozzles installed at both ends of the main trough formed in parallel with the water flow direction in the sand basin and the nozzles installed near the side walls of the sand basin are fed to the earth trough deposited on the bottom of the sand basin. Further, the main trough is configured to collect in a sand collecting pit provided at the center of the bottom of the sand basin (Patent Document 1).
In parallel with the sand collecting operation by this sand collecting device, the pumping pump installed in the sand collecting pit is automatically operated and stopped according to the water level in the sand collecting pit to maintain the drainage condition. However, the earth and sand collected in the sand collection pit is pumped up with water and discharged.

  In addition to sewage mixed with soil and sewage, such as sewage and rainwater, the settling basin includes various types of contaminants such as small and light garbage, light and large items such as plastic bottles and polystyrene foam, pebbles, gravel, Small and heavy items such as bottles and empty cans may flow in. When these contaminants flow into the sand collection pit, it will lead to the failure of the sand pump, so conventionally, when drainage occurs, the staff gathers the contaminants scattered on the bottom of the sand basin using tools, Eliminated.

  Since such manual work is inefficient and heavy labor, a foreign matter capturing screen (hereinafter referred to as a screen) for capturing various foreign matters mixed in the sewage before flowing into the sand basin. It was proposed to install.

  The screen according to this proposal captures light and large drifting or floating substances, such as PET bottles and foamed rolls, among the foreign substances, so that the maximum water level in the sand basin is reached from the bottom of the upstream end of the sand basin. It had a height up to a higher position, and was uniform over the entire surface. Therefore, there is little resistance to the flow of sewage, and there is no problem with the capture performance of light and large drifting objects or floating objects, but there is a risk that small and light garbage, small and heavy pebbles and gravel will pass through the screen. It was.

  In order to capture pebbles, gravel, etc., it was proposed to use a screen with a fine-grained surface. In this case, in addition to light and large floats or floats, there is an advantage that heavy and relatively small pebbles and gravel are captured, but even light and small drifts or floats, that is, large and small contaminants. Since the matter is captured, the screen is likely to be clogged. For example, in heavy rain, the water level on the upstream side of the screen becomes abnormally high, and the sewage reversely ejects from the manhole. There was a risk of becoming.

Japanese Patent No. 3315489

  The present invention has been made in view of the above circumstances. Capturing contaminants in a sand basin, which can capture drifting matter or suspended matter, pebbles, gravel, etc., regardless of size, and does not cause clogging on the screen. It is a first object to provide a screen for use.

  A second object of the present invention is to provide a screen for catching contaminants in a sand basin that can prevent a situation in which sewage is reversely ejected from a manhole or the like even if the screen is clogged. .

  In order to achieve the first object, the present invention is a screen for capturing foreign substances mixed in sewage immediately before flowing into a sand basin, and the screen is a bottom surface at an upstream end of the sand basin. From the lower end of the screen to a position lower than the assumed normal water level. It is characterized in that the portion is made finer than the roughness of the eyes (claim 1).

  The invention according to claim 2 is characterized in that the screen for catching foreign matter in the sand basin is provided with a first screen having a rough surface over the entire surface from the bottom surface at the upstream end of the sand basin to a level higher than the maximum water level for the time. It is characterized in that a second screen having a finer mesh than the first screen is overlapped over the entire surface from the bottom surface at the flow side end to a position below the normal water level assumed.

  Another feature of the present invention is a screen that captures foreign substances mixed in sewage such as rain water just before flowing into the sand basin, and the screen extends from the bottom surface at the upstream end of the sand basin to the upstream side of the screen. It has a height that rises above the maximum water level that is assumed for the period of time, and the portion of the screen from the lower end of the screen to the assumed normal water level is finer than the roughness of the upper portion from that position. (Claim 3).

  According to the invention of claim 4, the screen for catching foreign matter in the sand basin is provided with a first screen having a rough surface over the entire surface from the bottom surface at the upstream end of the sand basin to a level higher than the maximum water level for the time. It is characterized in that a second screen having a finer mesh than the first screen is superposed over the entire surface from the bottom surface at the flow side end to the assumed normal water level.

  Another feature of the present invention is a screen that captures foreign substances mixed in sewage such as rain water just before flowing into the sand basin, and the screen extends from the bottom surface at the upstream end of the sand basin to the upstream side of the screen. It has a height that rises above the assumed maximum water level in the area, and the eye of the portion from the bottom surface at the upstream end of the sand basin to the position between the assumed normal water level and the assumed maximum time water level That is, it is finer than the roughness of the upper portion from the position.

  The invention of claim 6 is characterized in that the screen for catching foreign matter in the sand basin is provided with a first screen having a rough surface over the entire surface from the bottom surface at the upstream side end of the sand basin to a level higher than the maximum water level for the time. The entire surface is superposed on a second screen that is finer than the first screen from the bottom surface at the flow side end portion to a position between the normal water level assumed and the maximum time water level assumed.

  According to the invention of claim 1, the contaminants flowing in at the normal water level with the highest frequency are effectively captured regardless of whether they are drifting or floating matter, pebbles or gravel. can do. And even if clogging occurs due to small impurities in the fine parts of the screen, when the water level becomes higher than the normal water level due to heavy rain, the sewage is located at a higher position than the clogging site. Since the rough portion overflows, sewage is prevented from being ejected from a manhole or the like.

  According to the second aspect of the present invention, the sediment trap of the sand basin in which the portion of the screen from the lower end of the screen to the position lower than the normal water level of the sand basin is made finer than the roughness of the portion above the position is captured. It is easy to manufacture the screen for use, and the strength against the flow load in the installed state can be increased.

  According to the invention of claim 3, even when the water level of the sewage flowing into the sand basin becomes higher than the normal water level, the foreign matter that is about to flow into the sand basin is treated as a floating object, floating substance, pebbles, Regardless of gravel or the like, it can be captured effectively regardless of the size or weight. And even if clogging occurs due to small impurities in the fine parts of the screen, when the water level becomes higher than the normal water level due to heavy rain, etc., the sewage is coarse at a position higher than the clogging site. Since the portion overflows, sewage is prevented from being ejected from a manhole or the like.

  According to the invention of claim 4, it is easy to manufacture a screen for catching impurities in a sand basin in which the portion of the screen from the lower end to the normal water level is finer than the roughness of the portion above the position. In addition, the strength against the flow load in the installed state can be increased.

  According to the invention of claim 5, even when the water level of the sewage flowing into the sand basin becomes higher than the position between the normal water level assumed and the time maximum water level assumed, it tends to flow into the sand basin. Contaminants can be effectively captured, whether large or light, whether they are drifting or floating or pebbles or gravel. And even if clogging occurs due to small impurities in the fine parts of the screen, when the water level becomes higher than the position between the normal water level assumed to be the normal water level assumed due to heavy rain, etc. Since the sewage overflows the coarse portion at a position higher than the clogging occurrence site, the sewage is prevented from being ejected from a manhole or the like.

  According to the invention of claim 6, the portion of the screen below the position between the assumed normal water level and the assumed maximum water level of the screen is made finer than the roughness of the portion above the position. It is easy to manufacture a screen for catching impurities in the sand basin, and the strength against the flow load in the installed state can be increased.

It is a longitudinal cross-sectional view of the rainwater treatment facility in which a screen for capturing foreign substances is installed. FIG. 2 is a partially omitted plan view of the range of line XX in FIG. 1. It is the YY sectional view taken on the line of FIG. It is a front view of the screen which concerns on one Embodiment of the Z arrow direction of FIG. It is a conceptual diagram which shows the foreign material capture condition by the screen of FIG. It is a conceptual diagram which shows the foreign material capture condition by the screen of other embodiment. It is a front view of the screen which shows other embodiment. It is a conceptual diagram which shows the foreign material capture condition by the screen of FIG. It is a schematic sectional drawing which shows the various structural examples of the screen which concerns on this invention.

Next, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a rainwater treatment facility, which has a sand basin 2 and a pump well 3 formed between side walls Wa and Wb on both sides. The settling basin 2 is connected to an inflow trough 4 from which sewage such as rainwater and sewage is collected from a sewage pipe line not shown. A dam device 5 is installed at the downstream end of the inflow dredge 4 to allow or block the inflow of the sewage W from the inflow dredge 4 to the sand basin 2. The screen 100 according to the present invention is installed immediately before the upstream end portion of No. 2. The screen 100 will be described in detail later.

  When the dam device 5 is opened, the sewage W flows into the settling basin 2 and further into the pump well 3, and when the water level reaches a predetermined height (L1 in FIG. 1), the sewage W is provided in the pump well 3. The drainage pump 6 is operated, the water in the pump well 3 is pumped up, and transferred to a terminal treatment plant or the like outside the figure.

  During the transfer, the earth and sand is precipitated from the sewage W mixed with the earth and sand that has flowed into the sand basin 2, and is deposited on the surface 7a of the bottom 7 of the sand basin. After the sewage flow into the sand basin 2, the dam device 5 is closed after a certain period of time when the amount of sediment deposited is expected to reach a predetermined value, and the sewage flow into the sand basin 2 is prevented. And if the water level of the sedimentation basin 2 and the pump well 3 falls by the drainage by the drainage pump 6, and becomes L2 (FIG. 1), the operation of the drainage pump 6 is stopped. Thereby, the preparation for the sand collecting operation by the sand collecting device is completed.

  Subsequently, automatic operation of the sand pump 9 installed in the sand collecting pit 8 formed at the center of the bottom of the sand basin 2 is started. When the water surface in the sand collection pit 8 is at a predetermined high position, the operation starts automatically. When the water in the settling basin 2 is pumped up and the water surface falls to a predetermined low position, the operation starts automatically. Is to be stopped. That is, the sand pump 9 repeats the start and stop of operation, and has a function of maintaining the water surface of the settling basin 2 in a drained state located in the sand collection pit. The water pumped from the settling basin 2 by the sand pump 9 is transferred to the sewage settling basin after the earth and sand are separated by a sand settling machine (not shown).

  Along with the start of operation of the sand pump 9, the feed water pump 10 provided in the pump well 3 is started, and water from the feed pump 10 is installed in the vicinity of the bottom 7 of the sand basin 2 (see FIG. 1) (see FIG. 3), and the earth and sand deposited on the entire bottom surface 7a are sprayed from the nozzles 11 toward the bottom surface 7a of the sand basin 2 along the bottom surface. And collected in a main trough 12 formed at the bottom of the sand basin 2 between the side walls Wa and Wb on both sides in parallel with the water flow direction in the sand basin.

  FIG. 3 shows an example in which nozzle headers H1, H2,... Formed by attaching a plurality of nozzles 11 to the mother pipe 11a at a predetermined interval are shown.

  Water from the water supply pump 10 is also sent to a nozzle 13 installed at the upper end of the main trough 12, and the earth and sand flowing down to the main trough 12 by the water supplied from the nozzle passes through the main trough 12 together with water. It flows and is collected in the sand collection pit 14.

  The water from the water supply pump 10 is also supplied to the nozzle 16 installed at the side wall side end of the inclined surface 15 inclined downward from the side walls Wa and Wb to the bottom surface of the sand collecting pit 10 in the longitudinal center of the sand basin 2. The earth and sand sent to the nozzle 15 by the water supplied from the nozzle is also collected in the sand collecting pit 14 together with the water.

  The water from the water supply pump 10 is further supplied to the agitation nozzle 17 that injects water into the sand collection pit 14 toward the suction port of the sand pump 9, thereby agitating the earth and sand in the sand collection pit 10. It is like that.

  Thus, the sewage mixed with the earth and sand collected and stirred in the sand collecting pit 10 is pumped up by the sand pump 9 and transferred to a sewage sand basin (not shown) through a sand set separator (not shown).

  2 in FIG. 2 is a small trough formed in parallel to the bottom surface of the sand basin 2 at a constant interval, and 19 in FIG. 1 is a filter installed at the downstream end of the sand basin 2.

  A plurality of, in the example of FIG. 3, three horizontal support members 101 are suspended between the side walls Wa and Wb on both sides at an appropriate distance on a straight line inclined by 60 degrees as an example on the sand basin 2 side. The screen 100 according to the present invention having a width equal to the distance between the side walls Wa and Wb is attached to the support member 101.

  As shown in FIG. 4, the lower part 100a of the screen 100 is finer than the conventional one, and the upper part 100b is coarser than the conventional one. The interval between the fine eyes of the lower portion 100a is 25 to 75 mm, and the interval between the coarse eyes of the upper portion 100b is 75 to 200 mm.

  As shown in FIG. 5, the lower portion 100a of the screen 100, that is, the portion of the screen from the lower end of the screen 100 to the position lower than the normal water level La assumed in the inflow trough 4 or the sand basin 2, If it is made finer than the upper portion 100b, among the foreign matters mixed in the sewage W flowing from the inflow dredge 4 toward the sand basin 2, the relatively heavy pebbles, gravel, empty cans, bottles 201, etc. are below the screen. Dust and the like 202 that are well captured by the side portion 100a and that are small and have a relatively large specific gravity are also captured by the lower portion 100a. In addition, light and large objects 203 such as PET bottles and polystyrene foam are captured by the upper portion 100b having a coarse mesh, so that almost all contaminants can be captured without causing clogging.

  The lower part 100a of the screen may be clogged by trapped pebbles, gravel 201, and small garbage 202, but the upper part 100b of the screen is rough, so the sewage stops its flow. Without clogging, the clogged portion can overflow. Accordingly, it is possible to prevent the occurrence of a situation where the sewage of the inflow trough 4 overflows and reversely ejects from the manhole during heavy rain.

  FIG. 6 shows that when the lower part of the screen is made finer than the upper part, the eyes from the lower end of the screen to the assumed height H1 of the normal water level La are made finer, and the eyes of the further parts are made. An example of roughening is shown.

  In this way, if the lower part 100a is made finer from the lower end of the screen to the position of the normal water level La assumed in the sand basin, and the upper part 100b is made coarser than that, It is possible to increase the amount captured by fine parts of relatively large specific impurities such as gravel and small garbage. If clogging occurs and the water level Lh1 exceeds the normal water level La due to heavy rain or the like, it is possible to overflow above the clogging portion, thus preventing the occurrence of reverse jetting from the manhole. Can be prevented.

  As illustrated in FIG. 7, the screen 100 narrows the eyes from the lower end to the height position H2 between the assumed normal water level La of the sand basin 2 and the assumed maximum water level Lm, You may comprise the eyes of the above part coarsely.

  The assumed maximum time level Lm is an approximate value obtained based on the maximum amount of time inflow from the inflow trough, the capacity of the sand basin, and the drainage capacity of the drainage pump 6.

  In this way, when the eyes up to the height position H2 between the normal water level La and the time maximum water level Lm are made finer and the eyes beyond that are made coarse, as shown in FIG. Even if the inflowing sewage level is higher than the normal water level La, the contaminants that are about to flow into the sedimentation basin, whether drifting or floating, pebbles, gravel, etc. Regardless, it can be effectively captured. And even if clogging occurs due to small impurities in the fine parts of the screen, when the water level Lh2 becomes higher than the position H2 between the normal water level and the highest water level due to heavy rain, the sewage is clogged. Since the coarse portion at a position higher than the generation site overflows, the sewage is prevented from being ejected from the manhole.

  Screens with different eye sizes between the lower part and the upper part may be constructed by welding the end parts of two types of screens with different mesh openings in the vertical direction or by connecting them with a connecting member. In addition, as shown in FIG. 9, in a state where the first screen 100A having a large area and a coarse mesh and the second screen 100B having a small area and a fine mesh are aligned with the lower ends of both screens aligned. It can also be constituted by connecting with a commonly used connecting member. In either case, it may be directly fixed to the support member 101, or may be fixed in a rectangular frame (not shown), and the frame may be attached to the support member 101. (A), (b), and (c) in FIG. 9 correspond to FIGS.

DESCRIPTION OF SYMBOLS 1 Rainwater treatment equipment 2 Sand basin 3 Pump well 4 Inflow trough 5 Dam device 100 Screen 100a Lower part 100b Upper part 201,202,203 Contaminant La Normal water level Lm Time highest water level 100A Coarse screen 100B Fine screen

Claims (6)

  In a screen that captures contaminants mixed in sewage, such as rainwater, just before flowing into the sand basin, the screen is more than the expected maximum water level upstream from the bottom surface at the upstream end of the sand basin. Has a height that rises upward, and the portion of the screen from the lower end of the screen to a position lower than the normal water level is made finer than the roughness of the upper portion from that position. Screen for catching debris in a sand basin.   2. The screen for catching debris in the sand basin according to claim 1, wherein the first screen having a rough surface over the entire surface from the bottom surface at the upstream end of the sand basin to a level higher than the highest water level assumed upstream, and the upstream of the sand basin Contamination of a sand basin characterized by overlapping a second screen that is finer than the first screen over the entire surface from the bottom surface at the side end to a position below the normal water level assumed. Capture screen.   In a screen that captures contaminants mixed in sewage, such as rainwater, just before flowing into the sand basin, the screen is more than the expected maximum water level upstream from the bottom surface at the upstream end of the sand basin. A sand basin characterized in that the portion of the screen from the lower end of the screen to the normal water level is made finer than the roughness of the upper portion of the screen from that position. Screen for capturing foreign substances.   4. The screen for catching foreign matter in a sand basin according to claim 3, wherein the first screen having a rough surface over the entire surface from the bottom surface at the upstream end of the sand basin to a level higher than the highest water level assumed upstream, and the upstream of the sand basin A screen for capturing foreign matter in a sand basin, comprising a second screen that is finer than the first screen over the entire surface from the bottom surface at the side end to the assumed normal water level.   In a screen that captures contaminants mixed in sewage, such as rainwater, just before flowing into the sand basin, the screen is more than the expected maximum water level upstream from the bottom surface at the upstream end of the sand basin. Has a height that rises upward, and the eye of the part from the bottom surface at the upstream end of the sand basin to the position between the assumed normal water level and the assumed maximum water level is the upper part of the eye from that position. A screen for catching impurities in a sand basin characterized by being finer than the roughness of the sand.   6. The screen for catching contaminants of a sand basin according to claim 5, wherein the first screen having a rough surface over the entire surface from the bottom surface at the upstream end of the sand basin to a level higher than the highest water level assumed upstream, and the upstream of the sand basin A sand basin characterized in that the entire surface is overlapped with a second screen that is finer than the first screen from the bottom surface at the side end to a position between the assumed normal water level and the assumed maximum water level. Screen for capturing foreign substances.

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