JP4303012B2 - Water treatment apparatus and water treatment method - Google Patents

Water treatment apparatus and water treatment method Download PDF

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Publication number
JP4303012B2
JP4303012B2 JP2003069855A JP2003069855A JP4303012B2 JP 4303012 B2 JP4303012 B2 JP 4303012B2 JP 2003069855 A JP2003069855 A JP 2003069855A JP 2003069855 A JP2003069855 A JP 2003069855A JP 4303012 B2 JP4303012 B2 JP 4303012B2
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Prior art keywords
water
pipe
filtered
raw water
sand filtration
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JP2004066217A (en
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忠義 永岡
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株式会社ナガオカ
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    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/001Processes for the treatment of water whereby the filtration technique is of importance
    • C02F1/004Processes for the treatment of water whereby the filtration technique is of importance using large scale industrial sized filters
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D24/00Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/02Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration
    • B01D24/10Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration the filtering material being held in a closed container
    • B01D24/14Downward filtration, the container having distribution or collection headers or pervious conduits
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D24/00Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/46Regenerating the filtering material in the filter
    • B01D24/4605Regenerating the filtering material in the filter by scrapers, brushes, nozzles or the like placed on the cake-side of the stationary filtering material and only contacting the external layer
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D24/00Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/46Regenerating the filtering material in the filter
    • B01D24/4605Regenerating the filtering material in the filter by scrapers, brushes, nozzles or the like placed on the cake-side of the stationary filtering material and only contacting the external layer
    • B01D24/4621Regenerating the filtering material in the filter by scrapers, brushes, nozzles or the like placed on the cake-side of the stationary filtering material and only contacting the external layer by nozzles acting on the cake side of the filter material, or by fluids acting in co-current direction with the feed stream
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D24/00Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/46Regenerating the filtering material in the filter
    • B01D24/4631Counter-current flushing, e.g. by air
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/006Water distributors either inside a treatment tank or directing the water to several treatment tanks; Water treatment plants incorporating these distributors, with or without chemical or biological tanks
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/72Treatment of water, waste water, or sewage by oxidation
    • C02F1/74Treatment of water, waste water, or sewage by oxidation with air
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/10Inorganic compounds
    • C02F2101/20Heavy metals or heavy metal compounds
    • C02F2101/203Iron or iron compound
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/10Inorganic compounds
    • C02F2101/20Heavy metals or heavy metal compounds
    • C02F2101/206Manganese or manganese compounds

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water treatment apparatus and a water treatment method, and in particular, a clay, bacteria, algae and other suspended solids in tap water raw water etc. are aerated by a simple and small apparatus without using a flocculant. The present invention relates to a water treatment apparatus that can be treated by oxidizing and flocking.
[0002]
[Prior art]
There are two methods of slow water filtration and rapid filtration as tap water filtration methods stipulated in the Japan Water Works Association water facility design guidelines.
[0003]
When the quality of the tap water is very good and stable, slow filtration is performed by putting the raw water directly into the sand filtration layer and passing it through the sand filtration layer at a slow speed. Insoluble substances and soluble substances are trapped and oxidatively decomposed. This method requires a large area for the sand filtration layer because of a slow speed (4 to 5 m / d) and a slow filtration speed, and enormous work is required for scraping off clogged sand on the surface layer. Further, when the quality of raw water is deteriorated, it is obliged to generate flocs by performing chemical treatment as a pretreatment, and to send the treated water to the sand filtration layer after sending the treated water to the settling basin.
[0004]
Rapid filtration, on the other hand, has the advantage that the filtration speed is as fast as 120 to 150 m / d and requires a small filtration area, and can be used even when the quality of raw water is poor. However, as a pretreatment, a flocculant such as aluminum sulfate is injected as a raw material. It is obliged to agglomerate suspended substances such as clay, bacteria, and algae in water into flocs in advance, settle them in a sedimentation basin, and send them to a sand filtration layer.
[0005]
[Problems to be solved by the invention]
In the rapid filtration type water treatment apparatus for injecting the flocculant, a relatively large amount of the flocculant is consumed, so that the purchase cost is high. In addition, the water treatment apparatus using this chemical injection method is composed of an aeration tank, a coagulation tank, a sedimentation tank, a sand filtration tower, and a chemical tank, and the system is complex, and the entire apparatus becomes large and requires a large installation space. . In addition, it is necessary to replace the filtration sand used in this chemical treatment water treatment equipment from time to time due to clogging due to accumulation of impurities. In this case, since the sand contains chemicals, it must be treated as industrial waste. In addition, there are inconveniences such as restricting the abandoned place.
[0006]
On the other hand, the washing of the sand filtration layer with backflow water (back washing) requires that the filter medium of the entire filter layer be thoroughly washed, and the quality of this back washing greatly affects the filtration efficiency. In the conventional rapid filtration device, a complicated and large structure is required for the lower water collecting device in order to enhance the backwashing effect, and since a lot of time is required for the backwashing operation, a huge amount of backwashing sewage is generated. For this reason, this backwashing sewage treatment apparatus is large.
[0007]
The present invention has been made in view of the shortcomings of the conventional rapid filtration water treatment apparatus using the chemical injection method described above, and is a simple and small-sized apparatus that uses suspended solids in raw water without using a chemical such as a flocculant. It is an object of the present invention to provide a water treatment device that can be treated by oxidizing and flocating with water.
[0008]
The present applicant has filed an application according to Patent Document 1 as a prior application related to the present invention.
[0009]
[Patent Document 1]
JP2002-126768
[0010]
[Means for Solving the Problems]
The water treatment apparatus of the present invention that achieves the above object includes a raw water water pipe, and a plurality of jets each having a raw water jet outlet that has one end communicating with the raw water water pipe and the other end jets raw water as a jet water stream. A nozzle, a sand filtration layer having a surface disposed below the jet nozzle at a predetermined interval from the raw water outlet, and the sand filtration layer for taking out water filtered by the sand filtration layer And a mechanism for reciprocating the raw water supply pipe on a plane parallel to the surface of the sand filtration layer.
[0011]
According to the present invention, a jet water flow is struck from the raw water outlet of the jet nozzle to the water surface on the sand filtration layer disposed below the jet nozzle, and a large number of bubbles are generated by entraining the air into the water. Vigorous aeration occurs on the sand surface. By this aeration, the clay, bacteria, algae and other suspended matter in the water are oxidized and trapped on the surface of the filter sand which forms flocs or precipitates to form a sand filter layer. The flocs formed in this way are easily captured on the surface of the filter sand. The filtered water obtained by filtering these flocs and other foreign matters through the sand filtration layer is taken out from the filtered water outlet.
[0012]
Therefore, according to the present invention, steps such as flocking by chemical treatment and coagulation sedimentation are unnecessary as pretreatment for sand filtration.
[0013]
Since the flocs of the oxide particles are trapped on the surface of the filtration sand, the filtration speed is as fast as 120 to 150 m / d, which is similar to rapid filtration, and a relatively narrow filtration area is sufficient.
[0014]
If the above filtration action is continued, oxide flocs and other foreign substances accumulate on the surface of the sand filtration layer over time, and the sand filtration layer surface is covered and blocked by flocks and other foreign substances. Although the filtration function is reduced, according to the present invention, a mechanism for reciprocating the raw water pipe on a surface parallel to the surface of the sand filtration layer is provided, so that the water surface is slightly above the surface of the sand filtration layer. By operating this mechanism in a state adjusted to, and reciprocating the raw water pipe on a surface parallel to the surface of the sand filtration layer, the jet water flow ejected from the raw water outlet of the jet nozzle is blocked on the sand filtration layer surface. By slamming hard, the clogging of foreign matter on the entire surface of the sand filtration layer is loosened, and the clogged state of foreign matter on the surface of the sand filtration layer is removed. After removing clogging on the surface of the sand filter layer in this way, the filtered water is made to flow backward from above the sand filter layer and the backwash waste water is discharged to the outside of the sand filter layer. Fully recover.
[0015]
In one aspect of the present invention, the water treatment device includes a clogging and loosening rod disposed such that a tip is inserted into a surface layer of the sand filtration layer between adjacent jet nozzles of the plurality of jet nozzles. It is characterized by being.
[0016]
With this configuration, during backwashing, when the raw water pipe is reciprocated on a surface parallel to the surface of the sand filtration layer, the clogging and unraveling rod is reciprocated while being inserted into the surface layer of the sand filtration layer. The surface layer of the sand filtration layer is cultivated by the clogging loosening rod, and the clogging on the surface of the sand filtration layer can be loosened more effectively.
[0017]
In one aspect of the present invention, a water treatment apparatus includes a plurality of jet nozzles including an air supply pipe, an air supply pipe having one end communicating with the air supply pipe, and the other end discharging air as a jet stream. A sand filtration layer whose surface is arranged below the jet nozzle at a predetermined interval from the air outlet of the jet nozzle, a water pipe for feeding raw water to the sand filtration layer, and the sand filtration layer. A filtered water outlet provided in the sand filtration layer for taking out filtered water, and a mechanism for reciprocating the air supply pipe on a plane parallel to the surface of the sand filtration layer. To do.
[0018]
According to this configuration, the suspended matter in the raw water sent to the sand filtration layer is oxidized and flocked by the aeration generated by the jet air stream ejected from the jet nozzle, and is the same as the apparatus for ejecting the jet water stream. It is trapped on the sand filter layer and filtered. The action of the jet air flow during backwashing is the same as that of the jet water flow.
[0019]
Also in this apparatus, the clogging loosening rod can be disposed between the adjacent jet nozzles of the plurality of jet nozzles so that the tip is inserted into the surface layer of the sand filtration layer. Surface clogging can be loosened more effectively.
[0020]
In one aspect of the present invention, during raw water filtration, a jet water stream is ejected from a jet nozzle to aerate the water on the sand filtration layer and the surface of the sand filtration layer, and when the sand filtration layer is backwashed, the jet There is provided a water treatment method characterized by operating a mechanism for reciprocating the raw water supply pipe while jetting a jet water flow from a nozzle, thereby removing clogging in the surface layer of the sand filtration layer by the jet water flow.
[0021]
In another aspect of the present invention, when the supply of filtered water is stopped, the filtered water circulating means for stopping the supply of the raw water from the raw water supply pipe and returning the filtered water to the raw water supply pipe to circulate in the sand filtration layer. Is further provided. A water treatment apparatus is provided.
[0022]
In the sand filtration layer, iron bacteria and other microorganisms naturally inhabit, and colonies of these microorganisms are formed. These microorganisms have the effect of removing impurities by oxidizing and adsorbing impurities such as iron and manganese in the raw water. According to the present invention, it is presumed that the aerobic and manganese removal effects are promoted by increasing the activity of these microorganisms as a result of a large amount of dissolved oxygen in the raw water being increased by aeration. According to the above configuration of the present invention, the filtered water is returned to the raw water pipe and circulated in the sand filtration layer even during a period in which the filtered water is unnecessary and the supply of the filtered water is stopped. Even during the period when the filtered water supply is stopped, the dissolved oxygen is sufficiently supplied to the iron bacteria and other microorganisms in the sand filtration layer. As a result, the microorganisms are prevented from being killed or reduced due to oxygen deficiency. It is possible to prevent a reduction in the effect of removing iron and removing manganese.
[0023]
The filtered water circulation means is provided in the filtered water circulation pipe connected to the filtered water outlet and the raw water feed pipe, a feed water pump connected to the filtered water circulation pipe, and the filtered water circulation pipe. When supplying water, the filtered water is supplied and the water supply to the filtered water circulation pipe is stopped. When the filtered water supply is stopped, the filtered water supply is stopped and the filtered water is supplied to the raw water supply pipe through the filtered water circulation pipe. A switching valve to be returned and provided in the raw water transmission path, pass raw water when supplying filtered water, stop passing filtered water from the filtered water circulation pipe, and stop passing raw water when filtered water supply stops And a valve means for allowing filtrate water from the filtrate water circulation pipe to pass therethrough.
[0024]
The filtered water circulation means includes a filtered water circulation outlet separate from the filtered water outlet, a filtered water circulation pipe connecting the filtered water circulation outlet and the raw water feed pipe, and the filtered water circulation pipe. Connected to the feed water pump and the filtered water outlet side pipe, opens when filtrate water is supplied, and closes when the filtrate water supply is stopped, and is provided in the raw water supply path. Provided with valve means for passing the raw water at the time of supply and stopping the passage of the filtered water from the filtered water circulation pipe and stopping the passage of the raw water at the time of stopping the filtered water supply and passing the filtered water from the filtered water circulation pipe It can also be configured as follows.
[0025]
In another aspect of the present invention, the water treatment apparatus further includes a backwash pipe embedded in the sand filtration layer, and the backwash pipe reverses the sand filtration layer blockage accumulated in the upper part of the sand filtration layer. It is deep enough to be removed by washing, and is buried in such a depth that a portion of the sand filtration layer that is as thick as possible exists below the backwash pipe.
[0026]
With this structure, the sand filtration layer blockage accumulated in the upper part of the sand filtration layer is washed away by backwashing, while the sand filtration layer below the backwashing pipe is not affected by backwashing. The colony of iron bacteria and other microorganisms present in the sand filtration layer below is not destroyed, and when the equipment is restarted after backwashing, iron removal and removal by microorganisms present in this part of the sand filtration layer The manganese effect is maintained and the iron removal and manganese removal effect as a whole water treatment device can be improved.
[0027]
In another aspect of the present invention, when raw water is filtered, a jet water stream is ejected from a jet nozzle to aerate the water on the sand filtration layer and the surface of the sand filtration layer, and when the sand filtration layer is backwashed, A water treatment characterized by operating a mechanism for reciprocating the raw water supply pipe while jetting a jet water flow from a jet nozzle, thereby removing clogging in the surface layer of the sand filtration layer by the jet water flow and the clogging releasing rod A method is provided.
[0028]
In another aspect of the present invention, when raw water is filtered, raw water is fed from the water pipe to the sand filtration layer, and a jet air stream is ejected from a jet nozzle to cause the water on the sand filtration layer and the surface of the sand filtration layer When the sand filtration layer is back-washed at a surface of the sand filtration layer by operating a mechanism for reciprocating the air supply pipe while ejecting a jet air flow from the jet nozzle. There is provided a water treatment method characterized by relieving clogging.
[0029]
In another aspect of the present invention, raw water is fed from the water pipe to the sand filtration layer at the time of raw water filtration, and a jet air stream is ejected from a jet nozzle connected to the air air pipe so as to be on the sand filtration layer. When aeration is performed on the surface of the water and the sand filtration layer, and the sand filtration layer is back-washed, the jet airflow is activated by operating a mechanism that reciprocates the air supply pipe while ejecting the jet airflow from the jet nozzle. And a water treatment method characterized by loosening clogging in a surface layer of the sand filtration layer with the clogging loosening rod.
[0030]
In another aspect of the present invention, when raw water is filtered, a jet water stream is ejected from a jet nozzle to aerate the water on the sand filtration layer and the surface of the sand filtration layer, and when the sand filtration layer is backwashed, A water characterized by operating a mechanism for reciprocating the raw water pipe in a state where jetting of a jet water flow from a jet nozzle is stopped so as to loosen clogging in the surface layer of the sand filtration layer only by the clogging loosening rod. A processing method is provided.
[0031]
In another aspect of the present invention, when raw water is filtered, raw water is supplied from the water supply pipe to the sand filtration layer, and a jet air stream is jetted from the air supply pipe so that the water and the sand filtration layer on the sand filtration layer are ejected. When the aeration is performed on the surface and the sand filtration layer is back-washed, the clogging loosening rod is activated by operating a mechanism that reciprocates the air supply pipe in a state in which the jet of the air flow from the air supply pipe is stopped. The water treatment method characterized by relieving the clogging in the surface layer of the sand filtration layer only by the above.
[0032]
In still another aspect of the present invention, when the filtered water supply is stopped, the supply of the raw water from the raw water supply pipe is stopped, the filtered water is returned to the raw water supply pipe and circulated in the sand filtration layer, and aeration is performed. A water treatment method characterized by further comprising a step of maintaining the dissolved oxygen concentration in the filtered water at a predetermined level by continuously performing the treatment.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a perspective view schematically showing one embodiment of a water treatment apparatus according to the present invention, in which a part of a side wall of a filtration tank is removed, and FIG. 2 is backwashed during filtration in the same embodiment. It is sectional drawing which shows the position of the jet nozzle at the time.
[0034]
The water treatment apparatus 1 includes, as main components, a filtration tank 3 that accommodates a sand filtration layer 2, a raw water supply pipe 4, a jet nozzle 5, and a raw water supply pipe reciprocating mechanism 20.
[0035]
A raw water supply pipe 4 made of a steel pipe or the like that supplies raw water such as river water to be filtered into the filtration tank 3 is connected to a raw water supply source (not shown) via a hose 27, and the raw water supply pipe at a predetermined flow rate. 4 is supplied with raw water.
[0036]
The raw water feed pipe 4 is disposed above the filtration tank 3 so as to be able to reciprocate on the parallel plane so as to extend on a plane parallel to the surface of the sand filtration layer 2. FIG. 1 is a view showing a state in which the raw water pipe 4 is reciprocating in the center of the filtration tank 3 during backwashing.
[0037]
A plurality of jet nozzles 5 are provided so as to branch vertically from the raw water feed pipe 4. An upstream end 5a of each jet nozzle 5 is fitted into the raw water feed pipe 4 so that the inside communicates with the raw water feed pipe 4, and a raw water jet that jets raw water as a jet water stream at the downstream end. An outlet 5b is formed. The inner diameter of the jet nozzle 5 is preferably about 3 to 6 mm, for example.
[0038]
In the filtration tank 3, the surface of the sand filtration layer 2 is disposed below the jet nozzle 5 with a predetermined distance (for example, about 35 cm) from the raw water jet 5 b of the jet nozzle 5. The sand filtration layer 2 is made of filtered sand, and functions to filter the raw water by capturing oxide floc and other foreign matters in the raw water supplied as a jet stream from the jet nozzle 5. The flow rate of water in the filtration tank 3, that is, the filtration rate varies depending on the target degree of foreign matter filtration (allowable concentration of foreign matter in filtered water) and the like, but it is preferably about the same filtration rate as rapid filtration, that is, 120 m to 150 m / d. .
[0039]
In the filtration tank 3, the sand filtration layer 2 is supported by a small support gravel layer 6 and a large support gravel layer 7 provided on the lower side thereof, and the large support gravel layers 7 are arranged in parallel. It is supported by a supporting gravel receiving plate 8 made of a wedge wire. Below the supporting gravel receiving plate 8 is a lower space 16 from which filtered water is discharged, and a filtered water discharge pipe 9 for taking out the filtered water is attached to the side wall of the filtration tank 3 facing this space 16. ing.
[0040]
A backwash pipe 15 for backwashing the sand filtration layer 2 is disposed in the lower space 16 in the filtration tank 3. The backwash pipe 15 has a large number of backwash water outlets 15a opened upward. The backwash tube 15 is connected to a backwash water supply source (not shown).
[0041]
As shown in FIG. 2, the raw water feed is provided between the raw water outlet 5 b of the jet nozzle 5 and the surface of the sand filtration layer 2 at one end 3 d of the filtration tank 3 where the raw water feed pipe 4 is located during filtration. A baffle plate 13 made of a steel plate or the like is provided so as to be parallel to the water pipe 4 and directly below the raw water outlet 5 b of each jet nozzle 5. Both ends of the baffle plate 13 in the longitudinal direction are fixed inside the opposing side walls 3a and 3b of the filtration tank 3 by means such as welding. As an example, if the water depth from the water surface in the filtration tank 3 to the surface of the sand filtration layer 2 is 30 cm, and the distance from the raw water outlet 5b of the jet nozzle 5 to the water surface is 5 cm, the depth from the water surface of the baffle plate 13 is About 5 cm (the distance from the raw water outlet 5 b is about 10 cm) is preferable.
[0042]
On both side portions 3a and 3b of the filtration tank 3, backwash water drainage ridges 18 are provided so that the upper edge is located above the surface of the raw water on the sand filtration layer. One end 18a of the tub 18 is closed, and the other end 18b is opened to discharge the backwash waste water to the outside.
[0043]
In the present embodiment, the raw water feed pipe reciprocating mechanism 20 that reciprocates the raw water feed pipe 4 on a surface parallel to the surface of the sand filtration layer 2 is fixed to one end portion of the raw water feed pipe 4 and a traveling wheel 21 at the bottom. A driving device 23 having a built-in electric motor and speed reducer for driving the traveling wheel 21 of the traveling box body 22 provided with a traveling plate 25 having a traveling wheel 24 fixed to the other end of the raw water pipe 4 and having a traveling wheel 24 at the bottom; A mechanism comprising a pair of rails 26 fixed to the frame 3e of the filtration tank 3 so that these traveling wheels 21 and 24 are engaged is used. The raw water feed pipe 4 travels in one direction by rotating the electric motor of the driving device 23 in one direction, and the raw water feed pipe 4 travels in the reverse direction by rotating the electric motor in the reverse direction.
[0044]
The reciprocating motion of the raw water supply pipe 4 is not limited to the illustrated mechanism, and other mechanisms such as a mechanism using a feed screw and a chain drive mechanism may be used.
[0045]
Next, operation | movement of the water treatment apparatus concerning this embodiment is demonstrated.
At the time of raw water filtration, raw water is supplied to the jet nozzle 5 through the raw water feed pipe 4 while maintaining the water depth on the surface of the sand filtration layer 2 at a predetermined depth (for example, about 30 cm). The raw water is jetted from the raw water outlet 5b as a jet water flow by setting the flow rate of the water to 1.5-3 liters / minute, for example. The jet stream of raw water is struck against the water surface on the sand filtration layer 2 and a large number of bubbles are generated, causing severe aeration on the water surface and the surface of the filtered sand. The baffle plate 13 promotes this aeration. By this aeration, components such as clay, bacteria, and algae are oxidized to form flocs or precipitate and are trapped on the surface of the filter sand that forms the sand filter layer 2. The filtered water in which these flocs and other foreign matters are filtered by the sand filtration layer 2 is taken out from the filtered water take-out pipe 9 to the outside.
[0046]
When the above filtering action is continued, oxide flocs and other foreign substances accumulate on the surface of the sand filtration layer 2 over time, and the surface of the sand filtration layer 2 is covered and blocked by the flocks and other foreign substances. Clogging occurs in the surface layer of 2, and the filtration function of the sand filtration layer 2 decreases.
[0047]
In this case, the raw water feed pipe reciprocating mechanism 20 is operated while supplying the raw water with the water surface adjusted to a predetermined level on the sand filtration layer surface (for example, about 10 cm above the sand filtration layer surface). Starting from the filtration position at the right end of 2, the raw water feed pipe 4 is reciprocated in the direction of the arrow on a plane parallel to the surface of the sand filtration layer 2 to be ejected from the raw water outlet 5 b of the jet nozzle 5. Since the jet water flow is slammed against the blocked surface of the sand filtration layer 2, the entire surface of the sand filtration layer 2 is cultivated, and clogging due to foreign matters on the surface of the sand filtration layer is removed. Restore the filtration function. After removing the clogging on the surface of the sand filtration layer 2 in this way, backwash water is flowed from the bottom of the sand filtration layer 2 through the support gravel receiving plate 8 made of a plate-like screen through the backwash pipe 15, thereby The washing water is discharged from the backwash water drain 18 to the outside.
[0048]
FIG. 3 is a perspective view similar to FIG. 1 schematically showing an embodiment of the invention in which aeration is performed by a jet air flow, which is another aspect of the present invention. In the embodiment of FIG. 3, the same components as those of the embodiment of FIG.
[0049]
The water treatment device 30 includes, as main components, a filtration tank 3 in which the sand filtration layer 2 is accommodated, a raw water feed pipe 38, an air feed pipe 34, a jet nozzle 35, and an air feed pipe reciprocating mechanism 20.
[0050]
A raw water supply pipe 38 made of a steel pipe or the like for supplying raw water such as river water to be filtered into the filtration tank 3 is connected to a raw water supply source (not shown), and the raw water is supplied through the raw water supply pipe 38 at a predetermined flow rate. It is supplied into the filtration tank 3.
[0051]
The air supply pipe 34 is disposed on the plane parallel to the surface of the sand filtration layer 2 so as to reciprocate on the plane parallel to the top of the filtration tank 3. FIG. 3 is a diagram showing a state in which the air supply pipe 34 is reciprocating in the center of the filtration tank 3 during backwashing. The air supply pipe 34 is connected to a compressed air source (not shown) such as an air compressor via a hose 39.
[0052]
A plurality of jet nozzles 35 are provided so as to branch vertically from the air supply pipe 34. The upstream end portion 35a of each jet nozzle 35 is fitted into the air supply tube 34 so that the inside thereof communicates with the air supply tube 34, and the air that jets air as a jet air flow at the downstream end portion. A spout 35b is formed. The inner diameter of the jet nozzle 5 is preferably about 3 to 6 mm, for example.
[0053]
In this embodiment, when raw water is filtered, raw water is fed from the raw water feed pipe 38 to the sand filtration layer 2, and a jet air stream is ejected from the jet nozzle 35 connected to the air feed pipe 34 to thereby cause the top of the sand filtration layer 2. When the sand filtration layer 2 is back-washed by aeration on the surface of the water and the sand filtration layer, the air feed pipe reciprocating mechanism 20 is operated while jet air flow is ejected from the jet nozzle 35, and sand filtration is performed by the jet air flow. The clogging in the surface layer of the layer 2 can be loosened.
[0054]
FIG. 4 is a view schematically showing an embodiment of the invention in which a clogging and loosening rod is provided between adjacent jet nozzles in another aspect of the present invention, viewed from the direction in which the raw water supply pipe reciprocates. It is a figure which removes and shows one side wall of a filtration tank. In FIG. 4, the same components as those in the embodiment of FIG.
[0055]
This embodiment is a modification common to both the embodiment in which aeration is performed by ejecting the raw water shown in FIG. 1 as a jet water stream and the embodiment in which aeration is performed by ejecting the air shown in FIG. 2 as a jet air stream. Since it is a form, in FIG. 4, the code | symbol of the component of FIG. 1 and FIG. 2 is written together and shown.
[0056]
In this embodiment, the water treatment apparatus 40 includes a clogging and unraveling rod 42 disposed between adjacent jet nozzles of the plurality of jet nozzles 5 or 35 of the raw water water pipe 4 or the air air pipe 34. ing. The clogging and loosening rod 42 is made of a rigid material such as steel, and its base 42a is fixed to the bottom wall of the raw water / water pipe storage cylinder 28 or the air / air pipe storage cylinder 37 by welding or the like, and its tip 42b is a sand filtration layer. 2 is inserted into the surface layer.
[0057]
With this configuration, the clogging loosening rod 42 is placed in the surface layer of the sand filtration layer 2 by reciprocating the raw water feed pipe 4 or the air supply pipe 34 on a surface parallel to the surface of the sand filtration layer 2 during backwashing. Since it reciprocates in the inserted state, the surface layer of the sand filtration layer 2 is cultivated by the clogging loosening rod 42, and the clogging of the surface of the sand filtration layer 2 can be more effectively loosened.
[0058]
In this embodiment, during raw water filtration, a jet water stream or a jet air stream is ejected from the jet nozzle 5 or 35 connected to the raw water feed pipe 4 or the air feed pipe 34 so that the water and the sand filter layer on the sand filter layer 2 are ejected. When the sand filtration layer 2 is back-washed by performing aeration on the surface 2, a mechanism 20 for reciprocating the raw water feed pipe 4 or the air feed pipe 34 while jetting a jet water stream or jet air stream from the jet nozzle 5 or 35 is provided. In operation, the clogging in the surface layer of the sand filtration layer 2 is loosened by the jet water flow or jet air flow and the clogging releasing rod 42.
[0059]
In another embodiment, during raw water filtration, a jet water flow or jet air flow is ejected from the jet nozzle 5 or 35 to aerate the water on the sand filtration layer 2 and on the surface of the sand filtration layer 2, thereby sand filtration. When the layer 2 is back-washed, the mechanism 20 for reciprocating the raw water supply pipe 4 or the air supply pipe 34 is operated in a state where the jet water flow or the jet air flow from the raw water supply pipe 4 or the air supply pipe 34 is stopped. The clogging in the surface layer of the sand filtration layer 2 is loosened only by the clogging and unpacking rod 42.
[0060]
FIG. 5 is a perspective view similar to FIG. 1 showing another embodiment of the present invention, and FIG. 6 is a sectional view similar to FIG. 2 of the same embodiment. In this embodiment, the same components as those in the embodiment of FIG.
[0061]
In the embodiment of FIG. 5, one or a plurality of backwash tubes 48 are embedded at a predetermined depth in the filter medium layer 2. The depth of embedding of the backwash pipe 48 is sufficient to remove the sand filtration layer blockage accumulated in the upper part of the sand filtration layer 2 by backwashing, and the sand filtration is as thick as possible below the backwash pipe 72. The depth is set such that the layer 2 portion exists. This depth is determined in consideration of various factors such as the type and amount of the sand filter layer blockage, the particle size of the sand forming the sand filter layer, the flow rate of backwash water, and the number of backwashes during a certain period. .
[0062]
In the sand filtration layer 2, colonies of iron bacteria and other microorganisms are naturally formed as the use period of the sand filtration layer 2 becomes longer, and the colonies of these microorganisms are not only the surface layer of the sand filtration layer 2 but also the sand filtration layer. As a result of the experiment, it was found that it was formed from the center part to the lower part of No. 2 and performed a considerable amount of iron removal and manganese removal action if not as much as the surface layer. That is, it has been found that the action of removing iron and removing manganese by microorganisms is performed at the entire depth of the sand filtration layer. Therefore, by embedding the backwash pipe 48 at such a depth position in the sand filtration layer 2, the sand filtration layer blockage accumulated in the upper part of the sand filtration layer 2 is washed away and removed by backwashing. Since the sand filtration layer 2 below the backwash tube is not affected by backwashing, the colonies of iron bacteria and other microorganisms present in the sand filtration layer below the sand filtration layer 2 are not destroyed. When the operation of the apparatus is resumed after backwashing, the effect of removing iron and removing manganese by the microorganisms present in this part of the sand filtration layer 2 is maintained and the effect of removing iron and removing manganese as a whole water treatment apparatus can be improved. it can.
[0063]
The water treatment apparatus according to this embodiment stops the supply of raw water from the raw water transmission pipe 4 during a period when filtered water is unnecessary, that is, when the filtered water supply is stopped, and returns the filtered water to the raw water transmission pipe 4 to sand filtration layer. 2 is further provided with filtered water circulation means 50 for circulating the inside of the inside.
[0064]
The filtered water circulation means 50 is connected to a filtered water circulation pipe 52 composed of a flexible pipe such as a hose for connecting the filtered water take-out pipe 9 and the hose 27 connected to the raw water supply pipe 4, and a filtered water circulation pipe 52. The feed water pump 58, the filtrate water circulation pipe 52, and the filtrate water take-out pipe 9 are connected to each other. When the filtrate water is supplied, the filtrate water is supplied and the water supply to the filtrate water circulation pipe 52 is stopped to supply the filtrate water. At the time of stoppage, the supply of filtered water is stopped, and the switching valve 54 for returning the filtered water to the raw water water pipe 4 side through the filtered water circulation pipe 52 is provided at the connecting portion of the hose 27 and the filtered water circulation pipe 52. A valve that allows the raw water to pass when the water is supplied and stops the filtered water from the filtered water circulation pipe 52, and stops the passing of the raw water and stops the filtered water from the filtered water circulating pipe 52 when the filtered water supply is stopped. And a switching valve 56 is stepped.
[0065]
When the filtered water supply is stopped, the switching valve 56 is switched so as to stop the passage of the raw water to the raw water feed pipe 4 and allow the filtered water to pass from the filtered water circulation pipe 52, while the switching valve 54 supplies the filtered water. When the feed water pump 58 is operated, the filtered water is switched from the filtered water take-out pipe 9 through the filtered water circulating pipe 52 to the raw water feed pipe 4. After being aerated through the jet nozzle 5, it falls onto the filter medium layer 2. Therefore, even during a period when the filtered water is unnecessary and the supply of the filtered water is stopped, the filtered water is returned to the raw water transmission pipe 4 and circulated through the sand filtration layer 2 and the aeration is continuously performed. The dissolved oxygen is sufficiently supplied to the iron bacteria and other microorganisms in the sand filtration layer 2, and as a result, the death and reduction of the microorganisms due to the lack of oxygen due to the shutdown of the apparatus are prevented, and when the filtered water supply is resumed Reduction of the effect of removing iron and removing manganese in the filtration layer 2 can be prevented.
[0066]
FIG. 7 is a perspective view similar to FIG. 5 showing a modified example of the filtered water circulation means. In this modified example, the filtered water circulation means 60 is a filtered water extraction pipe 61 separate from the filtered water extraction pipe 9 and a filtration material made of a flexible material such as a hose connecting the filtered water circulation extraction opening 61 and the hose 27. A water circulation pipe 62, a feed water pump 68 connected to the filtrate water circulation pipe 62, a valve 64 provided in the filtrate water take-out pipe 9, which opens when the filtrate water is supplied and closes when the filtrate water supply is stopped; 27 and the filtered water circulation pipe 62, the raw water is allowed to pass when the filtered water is supplied, the filtered water is stopped from passing through the filtered water circulating pipe 62, and the raw water is stopped when the filtered water supply is stopped. In addition, a switching valve 66 is provided as valve means for allowing the filtrate water from the filtrate water circulation pipe 62 to pass therethrough.
[0067]
In addition, various modified examples of the filtered water circulation means can be considered.
[0068]
In each said embodiment, although the water treatment apparatus provided with the filtration tank 3 which accommodated the sand filtration layer is provided, this invention is not restricted to this, The water purification plant by which the sand filtration layer is accommodated in the filtration pond The present invention can also be applied.
[0069]
【The invention's effect】
As described above, according to the present invention, a jet water stream or a jet air stream is struck against the water surface on the sand filtration layer disposed below from the jet nozzle, and a large number of bubbles are generated by entraining the air into the water. The surface of the filter sand where aeration occurs in the water and the surface of the filter sand causes the clay, bacteria, algae and other suspended substances in the water to oxidize to form flocs or precipitate to form a sand filter layer. Captured. Therefore, according to the present invention, steps such as flocking by chemical treatment and coagulation sedimentation are unnecessary as pretreatment for sand filtration.
[0070]
Since the flocs of the oxide particles are trapped on the surface of the filtration sand, the filtration speed is as fast as 120 to 150 m / d, which is similar to rapid filtration, and a relatively narrow filtration area is sufficient.
[0071]
Moreover, if the above filtration action is continued, oxide flocs and other foreign substances accumulate on the surface of the sand filtration layer over time, and the sand filtration layer surface is covered with and clogged with flocks and other foreign substances. Although the filtration function is reduced, according to the present invention, a mechanism for reciprocating the raw water pipe or the air air pipe on a plane parallel to the surface of the sand filtration layer is provided. By reciprocating the water pipe or air supply pipe on a plane parallel to the surface of the sand filtration layer, the jet water flow or jet air flow ejected from the jet nozzle is struck violently against the blocked sand filtration layer surface, thereby sand filtration. The clogging with foreign matter on the entire surface of the layer is relieved, and the clogged state due to foreign matter on the sand filtration layer surface is removed. After removing clogging on the surface of the sand filter layer in this way, the filtered water is made to flow backward from above the sand filter layer and the backwash waste water is discharged to the outside of the sand filter layer. Fully recover.
[0072]
Further, in one aspect of the present invention, the water treatment device includes a clogging and loosening rod disposed between the adjacent jet nozzles of the plurality of jet nozzles such that the tip is inserted into the surface layer of the sand filtration layer. Therefore, when backwashing, the clogging loosening rod is drawn into the surface of the sand filtration layer by reciprocating the raw water pipe or air feed pipe on a surface parallel to the surface of the sand filtration layer. By reciprocating, the surface layer of the sand filtration layer is cultivated by the clogging loosening rod, and the clogging of the surface of the sand filtration layer can be loosened more effectively.
[0073]
In another aspect of the present invention, when the supply of filtered water is stopped, the filtered water circulating means for stopping the supply of the raw water from the raw water supply pipe and returning the filtered water to the raw water supply pipe to circulate in the sand filtration layer. In addition, even during a period when the filtered water is not required and the supply of the filtered water is stopped, the filtered water is returned to the raw water transmission pipe and circulated in the sand filtration layer, and the aeration is continuously performed. During the suspension period, the dissolved oxygen is sufficiently supplied to the iron bacteria and other microorganisms in the sand filtration layer. As a result, the microorganisms are prevented from being killed or reduced due to lack of oxygen, and the iron removal in the sand filtration layer is resumed when the filtered water supply is resumed. Therefore, it is possible to prevent a decrease in the manganese removal effect.
[0074]
In another aspect of the present invention, the water treatment apparatus further includes a backwash pipe embedded in the sand filtration layer, and the backwash pipe reverses the sand filtration layer blockage accumulated in the upper part of the sand filtration layer. The sand accumulated in the upper part of the sand filtration layer is deep enough to be removed by washing and embedded in such a depth that there is a portion of the sand filtration layer as thick as possible below the backwash pipe. The filter layer blockage is washed away and removed by backwashing, while the sand filtration layer below the backwash tube is not affected by backwashing, so iron bacteria present in the sand filter layer below the backwash tube are removed. Other microbe settlements are not destroyed, and when the operation of the equipment is resumed after backwashing, the effects of iron removal and manganese removal by microorganisms present in this part of the sand filtration layer are maintained and the water treatment equipment as a whole Can improve iron removal and manganese removal effect
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing one embodiment of a water treatment apparatus of the present invention.
FIG. 2 is a cross-sectional view showing the position of the jet nozzle during filtration and backwashing in the same embodiment.
FIG. 3 is a perspective view schematically showing another embodiment of the water treatment apparatus of the present invention.
FIG. 4 is a side view showing another embodiment of the water treatment apparatus of the present invention.
FIG. 5 is a perspective view showing another embodiment of the water treatment apparatus of the present invention.
FIG. 6 is a cross-sectional view showing the position of the jet nozzle during filtration and backwashing in the same embodiment.
FIG. 7 is a perspective view showing a modification of the embodiment.
[Explanation of symbols]
2 Sand filtration layer
3 Filtration tank
4 Raw water pipe
5, 35 Jet nozzle
20 Raw water water pipe reciprocating mechanism
42 Rod for clogging

Claims (2)

  1. A raw water water pipe, a plurality of jet nozzles having one end communicating with the raw water water pipe, and the other end having a raw water jet for jetting the raw water as a jet water stream, and a raw water jet of the jet nozzle A sand filtration layer disposed below the jet nozzle at a predetermined interval; a filtered water outlet provided in the sand filtration layer to take out water filtered by the sand filtration layer; In a water treatment apparatus comprising a filtered water circulation means for stopping the supply of raw water from the raw water supply pipe at the time of stoppage and returning filtered water to the raw water supply pipe to circulate in the sand filtration layer,
    The filtered water circulation means includes
    A filtered water circulation pipe connecting the filtered water outlet and the raw water pipe;
    A feed water pump connected to the filtered water circulation pipe;
    Provided in the filtered water circulation pipe, when filtered water is supplied, filtered water is supplied and water supply to the filtered water circulating pipe is stopped, and when filtered water supply is stopped, filtered water is stopped and filtered water is filtered. A switching valve for returning to the raw water pipe through a water circulation pipe;
    Provided in the raw water supply path, when the filtered water is supplied, the raw water is allowed to pass through and the filtered water from the filtered water circulation pipe is stopped, and when the filtered water supply is stopped, the raw water is stopped from being passed from the filtered water circulating pipe. And a valve means for allowing the filtered water to pass therethrough.
  2. A raw water pipe, a plurality of jet nozzles having one end communicating with the raw water pipe, the other end having a raw water jet for jetting raw water as a jet water stream, and a surface having the raw water jet of the jet nozzle A sand filtration layer disposed below the jet nozzle at a predetermined interval; a filtered water outlet provided in the sand filtration layer to take out water filtered by the sand filtration layer; In a water treatment apparatus comprising a filtered water circulation means for stopping the supply of raw water from the raw water supply pipe at the time of stoppage and returning filtered water to the raw water supply pipe to circulate in the sand filtration layer,
    The filtered water circulation means includes
    A filtered water circulation outlet separate from the filtered water outlet;
    A filtered water circulation pipe connecting the outlet for circulating filtered water and the raw water pipe;
    A feed water pump connected to the filtered water circulation pipe;
    A valve provided in a pipe line on the filtrate outlet side, which opens when filtrate water is supplied, and closes when filtrate water supply is stopped;
    Provided in the raw water supply path, when the filtered water is supplied, the raw water is allowed to pass and the filtered water from the filtered water circulation pipe is stopped. When the filtered water supply is stopped, the raw water is stopped from passing and the filtered water circulating pipe water treatment device you characterized in that it comprises a valve means for passing the filtered water.
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DE102006027031A1 (en) 2006-06-08 2008-01-24 Verink, Johan, Dr.-Ing. Apparatus for wastewater treatment and a system equipped with such a device
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US20110278213A1 (en) * 2009-04-30 2011-11-17 Toyofumi Miyazaki Slow filtration device having excellent ability to treat microorganisms
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CA2878785C (en) * 2012-07-16 2019-06-11 Sonitec-Vortisand Technologies Inc. Media bed filters for filtering fine particles from a raw liquid flow and method of using the same
AU2014210349A1 (en) * 2013-01-24 2015-08-20 Sonitec-Vortisand Technologies Inc. Reactor with antimicrobial medium for liquid disinfection

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