CA1304839C - Aeration type water treating device - Google Patents
Aeration type water treating deviceInfo
- Publication number
- CA1304839C CA1304839C CA000538520A CA538520A CA1304839C CA 1304839 C CA1304839 C CA 1304839C CA 000538520 A CA000538520 A CA 000538520A CA 538520 A CA538520 A CA 538520A CA 1304839 C CA1304839 C CA 1304839C
- Authority
- CA
- Canada
- Prior art keywords
- water
- filter bed
- net
- tank
- circulation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Landscapes
- Biological Treatment Of Waste Water (AREA)
Abstract
ABSTRACT
In a water treating device with a water wheel arranged on upper side of an immersion filter bed for performing surface aeration, the immersion filter bed is composed of a plurality of filter bed elements including a net-shaped substance as main element, which elements are stood in parallel or laminated.
In this constitution, the microorganisms are adhered and activated throughout the whole filter bed, and closing due to waste substances is not easily produced, thereby the water treating efficiency is significantly improved.
In a water treating device with a water wheel arranged on upper side of an immersion filter bed for performing surface aeration, the immersion filter bed is composed of a plurality of filter bed elements including a net-shaped substance as main element, which elements are stood in parallel or laminated.
In this constitution, the microorganisms are adhered and activated throughout the whole filter bed, and closing due to waste substances is not easily produced, thereby the water treating efficiency is significantly improved.
Description
~3~
The present invention relates to a water treating device having a water wheel arranged on upper side of an i~mersion filter bed so as to perform surface aeration, which device can be used in treatment of not only industrial wastewaters but also sewage water exhausted ~rom hospitals, of~ices, houses or the like.
A water treating device of above-mentioned type in the prior art is disclosed, ~or example, in Japanese patent publication No. 54638/1983.
The water treating device is constituted in that a water wheel is rotatably fixed on upper side of a treating tank, a circulation partitioning plate with lower side opened i8 installed from ju~t below a water raking-out member of the water wheel throughout the whole width region of the treating tank, the water level is adjusted so that a part of the water raking-out member of the water wheel i~ sun~ in the water, water circulation is generated from the circulation partitioning plate as the border by rotating the water wheel, and an immersion filter bed is arranged at least on on~ side of the circulation partitioning plate.
The immersion filter bed is formed by contact ~3~3~
materials such as Rasching ring, plastic short tubes in net shape or small stones (gravel), filled or suspended.
In the filter bed constituted by the contact materials, however, if the specific gravity of the contact material i5 more than 1.0, the voidage is gradually decreased towards the bottom o~ the treating tank. On the other hand, if the specific gravity is less than 1.0, the voidage is gradually decreased towards the top of the treating tank.
Conse~uently, it is di~ficult to obtain the contact flow of suitable rate for adhering and activation of microorganisms (I~ too slow, the microorganisms cannot be adhered; if too rapid, oxygen supply becomes insufficient), and to secure the voidage which cannot be closed by flocks or waste throughout the whole filter bed. If closing of the immersion filter bed is produced, the filter bed must be washed. However, the washing is troublesome and not preferable because the microorganisms are washed away (Time is required for the microorganisms to be adhered to the filter bed again).
According to the invention there is provided an aeration type water treating device comprising: a treating tank, an immersion ~ilter bed in said tank composed of a plurality of filter bed elements each including a flat net tube as a main element, and means for vertically positioning said bed elsments in parallel, a water wheel rotatably ~ixed on an upper side of said tank for performing surface aeration and having at least one water raking out member, a circulation partitioning plate with lower side open installed from a position just below the at least one water raking out member of the water wheel across the whole width of said tank, and means for adjusting the water level in the tank so that a part of the water raking out member is sunk in the '~
~3~
water while circulation flow is produced from said circulation partitioning plate as the border by rotating the water wheel, said immersion filter bed being arranged at least on one side of said circulation partitioning plate.
FIG. 1 is a sectional view illustrating a first embodiment of the invention taken in line I - I of FIG. 2;
FIG. 2 is a sectional view taken in line II - II of FIG. 1;
- FIG. 3 is a plan view of FIG. l;
FIG. 4 is a sectional view illustrating a modification of the first embodiment of the invention;
FIG. 5 is a sectional view illustrating another modification of the first embodiment of the invention;
FIG. 6 is a sectional view illustrating a second embodiment of the invention;
FIG. 7 is a plan view illustrating a third embodiment of the invention;
~' ~ FIG. a is a sectional view of FIG. 7;
: FIG. 9 is a sectional view illustrating a fourth : 20 embodiment of the invention;
FIG. 10 is a perspective view of an immersion filter :~3~ 33~
bed with filter bed elements suspended ;
FIG. ll is a perspective view of a net tube as a L`:irst example of net-shaped substances to be used :Ln the invention ;
FIG.'12 is a perspective view of a flat net tube as another example of net-shaped substances ;
FIG. 13 is a front view of a fishing net as another example of net-shaped substances ;
FIG. 14 is a front view of a net sheet as another example of net-shaped substances ;
FIG. 15 is a front view illustrating an example of f`ilter becl elements to be used in the invention ;
FIG. 16 is a front view illustrating another example of filter becl elements ;
: FIG. 17 is a front view illustrating another example of filter bed elements ;
; FIG. 18 is a f'ront vieW illustrating another example of filter bed elements ;
FIC. 19 is a front view illustrating another example of filter bed elements ;
F'IG. 20 is a front view illustrating another example of filter bed elements ;
FIG. 21 is a perspective view il.lustrating an example of water wheels to be used in the invention ;
FIG. 22 is a perspective view illustrating another example of water wheels ; and FIG. 23 is a perspective view illustrating another example of water wheels.
In an embodiment shown in FIGS. 1 - 3, a water wheel 3 is fixed horizontally on upper ~ide of a treating tank 1, a circulation partitioning plate 2 is installed from position just below a water raking-out member 6 of the water wheel 3 towards the bottom of the traating tank 1 and spaced from the bottom of the treating tank 1 by a gap being about 10 - 30%
o~ the longitudinal length of the circulation partitioning plate 2, and water raked out by the water raking-out member 6 during rokation of the water wheel 3 cannot be returned through a gap between the water wheel 3 and a tank wall due to a xeverse flow inhibiting plate 8 to prevent the returning. Also the water cannot be returned through a small gap between lower side of the water wheel 3 and the top of the circulation partitioning plate 2 due to water urged one by one by the raking-out member 6 being rotated while the water wheel 3 is rotated. Consequently, ince the water level is elevated at receiving side o~ the raked-out water and lowered at delivering side of the raked-out water, the raked-out water is returned through an opening at the bottom of the cir~ulation partitioning plate 2 thereby ~irculation flow 7 i~ produced within the tr~ating tank 1. A number of filter bed elements 4a, 4b are installed on one side of the circulation partitioning ~3~33~
plate 2 in the treating tank 1 and spaced from each other by a def`inll;e di.stance corresponding to the sewage load ,so as to constitute an immersion filter bed 4.
In this constitution, the contact oxidation i9 perfOr'me( repeate(lly by the circulation flow.
Position of installing the imrnersion fi:Lter bed 4 in the treating tank 1 is not limited to the above-mentioned position, but the immersion filter bed 4 may be formed on both sides of the circulation partitioning plate 2 as shown in ~IG. 4 (suitable for the sewage treatment at relatively :low concentration), or a plurality of water wheels 3 may be :installed on both sides in the treating tank 1 and the immersion filter bed 4 may be provided between the circulation partitioning plate 2 on both sides as shown in FIG. 5 (suitable for the sewage treatrnent at high concentration requiring much circul.ation flow 7 by aeration).
In FIG. 6, the treating tank 1 is made deep and the circulation partitioning plate 2 is made long, thereby the treating tank 1 with large capacity at small inst.allation area may be formed (very effective at little space). In the case of` the sewage of high concentration, if the mounting number of water wheels is limited due to the installation space and the quantity of the circulation flow 7 by aeration seems little, the quantity will be increased by increasing the rotational speed of the water wheels. However, if more quantity is required, as shown in FIG. 6, auxiliary aeration ~3~
may ~e performed at side without installation of the 3mmersion filter bed 4 using an air scattering tube 25, or a circulating pump 26 may be installed and water sprinkling aeration be performed to side where water is raked out by the water wheel 3 thereby the circulation flow rate is increased and the deep shaft system can be perf`ormed.
The circulating pump 26 may be an water-immersible propeller pump or a vertical pump being a pump of larger water amount at low lift and having energy saving property and much outgoin~
amount.
Ne~t, installation mode of the filter bed elements 4a, 4b to the treating tank will be described.
The filter bed elements 4a, 4b may be vertically instaLled in parallel to the circulation partitioning plate 2 as shown in FIGS.1 - 6, vertically installed in perpendicular to the circulation partitioning plate 2 as shown in FIGS. 7 - 8, or horizontally installed in perpendicular to the circulation ~artitïoning plate 2 as shown in ~IG. 9.
Ihe installation method in FIG. 9 is suitable for tertiary treatment of the sewage of low concentr1ation and purification of water of little load such as orginal water in a water supply business, but the vertical installation with a definite spacing is preferable in the case of the sewage treatment of medium or high concentration.
~3(~Z33~
Installation of the filter bed elements lla to the treatil1g tanlc I may be performed by fixing them one by one to the ~re.lting tank 1, but as shown in FIG. 3 and F'IG. 7, method of installing slide frames 22 to the treating tank 1 and fitting the filter bed elements 4a thereto by falling is simple and prefer7able. When the filter bed ele~lents 4a are installed horizontally as shown in FIG. 9, the filter bed elements 4a may be supported by a receptable 23 of lack type.
~ s shown in FIG. 10, when the filter bed elements 4b each mounted through an upper support bar 18a are fitted respectively to a number of slits 21 of a filter bed element suspending frame 20 and hung down so as to constitute the immersion filter bed 4, the filter bed element suspending frame 20 may be supported by a receptacle support tool 24 attached to the treating tank 1 as shown in FIG. 8.
In a method that a net~shaped substance 5 such as a cylindrical net tube 5a (FIG. 11 ), a flat net tube 5b (FIG.
12), a fishing net 5c (FIG. 13) or a net sheet 5d (FIG. 14) is used as basic member of the filter bed element 4a and spread on a filter bed element support frame 17, four ends of the net-shaped substance may be fixed using pressing plates, screws or the like, the net-shaped substance may be wrapped to the frame 17 and bonded, or the net-shaped substance may be fi~ed to the frame 17 using string-shaped substance such as wire by knitting.
Concrete modes of the installation are shown in - .~ ~
13~3~39 tIGS. 15 - 17.
FIG. 15 shows an example of the filter bed e:lement 4a where the net-shaped substance 5 is mounted to the f`ilter bed element support frame 17 ;
FIG. 16 shows another example of the filter bed element ~la where the net-shaped substance 5 is mounted to the filter bed element support frame 17 at a definite spacing ; and FIG. 17 shows still another example of the filter bed element 4a where the net-shaped substance 5 is mounted to the filter bed element support frame 17 at cross Zig-Zag form.
In the case of the filter bed element 4b of suspension type, as shown in FIGS. 19 - 20, the net-shaped substance 5 is wrapped and returned on the upper support bar 18a with notched portions 27 provided on both ends, and the contact part is bonded or bound by knitting using a string-shaped substance such as wire or fixed using a pressing plate and a screw. The lower end of the net-shaped substance 5 is mounted to the lower support bar 18b in similar manner to the upper end.
Concrete modes of the installation are shown in I~IGS. 18 - 20.
FIG. 18 shows an example of the filter bed element 4b where the net-shaped substance 5 is installed to the filter bed element support bars 18a, 18b throughout the whole surf`ace ;
_ 9 _ .
~3C~t33~
FI~. 19 shows another example of the filter bed element 4b where the net-shaped substance 5 is installed to the fllter becl element support bars 18a, 18b at a definite spacing ; and FIG. 20 shows still another example of the f:ilter bed element ~b where the net-shaped substance 5 is installed to the filter bed element support bars 18a, 18b at Zig-Zag lattice form.
The filter bed support frame 17, the suspension frame 20 and the filter bed element support bars 18a, 13b are prefer-ably made of iron or stainless steel on account of workability t strength and low cost. The lower support bar 18b serves also as a weight.
The net tube 5a has diameter of 5cm - 20cm, thicl~ness of the net element wire 16 being 5mm - 10mm, and size of each mesh being about 30mm - 80mm. Since the net tube 5a is of pipe form, it is stout and suitable for ~he treatment at h:igh concentration. The flat net tube 5b is 5cm - 20cm wide and 5mm - 15mm thick, and has thickness of the net element wire being 0.5mm - 2mm and size of each mesh being about 3mm -15mm. Even when the ret of the flat net tube 5b is composed of the thin element wires 167 it has strength on account of double structure due to the flat pipe form. The fishing net 5c preferably has thickness of the element wire 16 being 2mm -4mm and size of each mesh being about 20mm - 60mm.
The flat net tube 5b is better from the viewpoints of strength, ~3~
amoul1t of` the ~naterial in use, price and machining into the f`i.lter bed elelnents 4a, 4b during the net manufacturing, and can be manuf`actured in mass production by extrusion molding and ha3 strength even using the thin element wires 16 and can be used widely for the treatment of the sewage frorn low concentration to high concentration. Since a nun1ber Or the net tubes each being as narrow as 5cm - 20cm are set to the filter bed elements 4a, 4b, each tube is independent and can be flut;~;ere(l even by pressure of the water flow and the contact eff`iciency to the microorganisms is increased corr1esponding to the movement even if it is slight.
~; Next, modes of water wheels to be used in the inventlon are shown in FIGS. 21 - 23.
FIG. 21 shows an example of the water wheel where the water raking-out members 6 are of plate form ;
FIG. 22 shows another example of the water wheel where the water raking-out members 6 are of tubular form ; and FIG. 23 shows still another example of the water wheel where the water raking-out members 6 are of comb-like for-m extending radially.
Use modes in the above-mentioned embodiments will now be described.
In the invention, the energy-saving water wheel of , low speed rotation (peripheral speed of 30 - 60 m/minute) rakes out the large water quantity throughout the overall len~th of the raking-out members 6 of the water wheel, and !
~3~"483~
the c:irculation flow 7 of the large water quantit~ by aerat:Lon is produced from the circulation partitioning plate 2 clS the borcler for the contact oxidation. In this constitution, the circulation f`low rate is significantly large in comparlson to that by an air lift, and therefore the circulation water paths large in number and width are required and the dead space ~; of the immersion filter bed 4 becomes little, thereby the contact efficiency to the microorganisms becomes well corres-pondingly.
If the ralcing-out member 6 of the water wheel is formed by a porous plate or a porous tube with large surface area, during the rotation~ a thin water film is dropped on the sur~ace of the raking out member 6 and exposed to the air thereby oxygen in the air is dissolved in the water.
On the contrary, since organic substance in the water is radlated into the air by the exposure, the substitution action can be effected although it is impossible in the aeration using a blower or a compressor.
~, 'I'he net tubes 5a, 5b and the net sheet 5d as basic substance for the filter bed elements 4a, 4b of the immersion f`ilter bed 4 to be used in,the invention can be manufactured in mass production at low cost as extrusion molding products of polyethylene resin or polypropylene resin, thereby the net tube having the net element wire 16 being thin or thick and the mesh being fine or coarse can be freely selected depending on the sewage load, Even if the resin net is broken at one ~L3~4~
position, the breakage is not spread. The resin net is used also as a net for stopping sand and is very strong, and the water flow can pass in any direction horizontally and vertically due to the mesh structure and the contact efficiency is well.
Respective spacings of the filter bed elements 4a, 4b are selected to 30mm - lOOmm depending on the water load to be treated, i,e., the contact area load. In the case of the sewage treatment at low concentration, since the contact area load is llttle, the contact area is required rnuch and therefore the net-shaped substance 5 with fine mesh is used and the filter bed elements 4a, 4b are installed at the narrowed spacing. In the case of the treatment at high concentration, since the contact area load can be taken much, the mesh may be coarse and the spacing o~ the filter bed elements 4a, 4b may be wide. Since the raw material for the mesh-shaped substance 5 is a net, the contact area per unit volume is very large.
Consequently, even if the immersion filter bed 4 is installed in a small treating tank, since the contact area is large and the circulation flow 7 subjected to aeration is much, the treating tank being very compact in comparison to other can be designed. If there is a treating tank 1 already installed, a circulation partitioning plate 2 matched to the tanlc 1 may be f~llen and fixed thereto and the water wheel 3 may be installed on upper side. In this state, if the filter bed element 4a is fallen or the filter bed element 4b of suspension 13~ 39 type ls hung, the treating tanlc 1 already instal:le(l can be r~econ3~;rlucted simply. Particularly the reconstructiorl of the standal-(l activation sludge method results in the signi.ficarlt ener~y savin~ in comparison to the blower aeration. Since the contact oxidation by the net-shaped substance 5 is perf`ormed, in the interior of the microorganism film adhered to the bed, the aerobic digestion and the anaerobic self-cligest:ion are promoted by the circulation flow 7 subjected to aeration,. thereby the excessive sludge is significantly decreassed and the treatment water quantity is slgniL`:icantly increased.
Since the filter bed elements 4a, 4b are installed in the circulation water flow paths of the treating tank 1 at a definite spacing, the closing obstruction of the lmmersion filter bed 4 as a whole cannot occur but water urged by the raking-out member 6 of the water wheel always becomes pulse flow. rhe filter bed elements 4a, 4b are oscillated by the pulse circulation flow 7, and the contact ef.ficiency between the microorganisms and the sewage is increased. In the microorganism film with the weakened activity, due to the oxygen moving by the circulation flow from the interior of the f`ilm, the activation of the aerobic bacteria is usually increased and the digestion of sludge is promoted. Natural separation occurs in a large mass from meshes of the net-shaped substance 5, and sedimentation occurs between the filter bed elelnents 4a, 4b. Since deposit to the sludge ~3~39 de~)03it portion 12 occurs, washing of the immersion filter bed 4 is no~. requir-~ed but the excessive sludge in the ~eposit portion may be regularly exhausted by a sludge exhaust tube 13.
The natural separation occurs with time lapse in some positions among a number of the net-shaped substances 5 in the immerslon filter bed 4. Since the circulation flow 7 is well, new microorganisms are immediately aclherecl to the bed where the separation occured, thereby variatlon of` the water quality due to the natural separation of the micro-organisms does not occur. Artificial treatment SUCtl as washin~
is not applied to the immersion filter bed 4 of the treating tanl~ 1at any time, but the microorganism environment is always held to the definite condition in the natural state thereby the stable treatment water can be always obtained.
If a water immersible air scatterin~ tube is arranged in place of the water wheel in each embodiment of the invention, although effects of the invention cannot be fully achieved, this constitution can be used as a water treatment device having good water treating efficiency in comparison to the prior art.
It the water wheel is omitted in each embodiment of the invention, the device can be used also as a deposit tank.
The present invention relates to a water treating device having a water wheel arranged on upper side of an i~mersion filter bed so as to perform surface aeration, which device can be used in treatment of not only industrial wastewaters but also sewage water exhausted ~rom hospitals, of~ices, houses or the like.
A water treating device of above-mentioned type in the prior art is disclosed, ~or example, in Japanese patent publication No. 54638/1983.
The water treating device is constituted in that a water wheel is rotatably fixed on upper side of a treating tank, a circulation partitioning plate with lower side opened i8 installed from ju~t below a water raking-out member of the water wheel throughout the whole width region of the treating tank, the water level is adjusted so that a part of the water raking-out member of the water wheel i~ sun~ in the water, water circulation is generated from the circulation partitioning plate as the border by rotating the water wheel, and an immersion filter bed is arranged at least on on~ side of the circulation partitioning plate.
The immersion filter bed is formed by contact ~3~3~
materials such as Rasching ring, plastic short tubes in net shape or small stones (gravel), filled or suspended.
In the filter bed constituted by the contact materials, however, if the specific gravity of the contact material i5 more than 1.0, the voidage is gradually decreased towards the bottom o~ the treating tank. On the other hand, if the specific gravity is less than 1.0, the voidage is gradually decreased towards the top of the treating tank.
Conse~uently, it is di~ficult to obtain the contact flow of suitable rate for adhering and activation of microorganisms (I~ too slow, the microorganisms cannot be adhered; if too rapid, oxygen supply becomes insufficient), and to secure the voidage which cannot be closed by flocks or waste throughout the whole filter bed. If closing of the immersion filter bed is produced, the filter bed must be washed. However, the washing is troublesome and not preferable because the microorganisms are washed away (Time is required for the microorganisms to be adhered to the filter bed again).
According to the invention there is provided an aeration type water treating device comprising: a treating tank, an immersion ~ilter bed in said tank composed of a plurality of filter bed elements each including a flat net tube as a main element, and means for vertically positioning said bed elsments in parallel, a water wheel rotatably ~ixed on an upper side of said tank for performing surface aeration and having at least one water raking out member, a circulation partitioning plate with lower side open installed from a position just below the at least one water raking out member of the water wheel across the whole width of said tank, and means for adjusting the water level in the tank so that a part of the water raking out member is sunk in the '~
~3~
water while circulation flow is produced from said circulation partitioning plate as the border by rotating the water wheel, said immersion filter bed being arranged at least on one side of said circulation partitioning plate.
FIG. 1 is a sectional view illustrating a first embodiment of the invention taken in line I - I of FIG. 2;
FIG. 2 is a sectional view taken in line II - II of FIG. 1;
- FIG. 3 is a plan view of FIG. l;
FIG. 4 is a sectional view illustrating a modification of the first embodiment of the invention;
FIG. 5 is a sectional view illustrating another modification of the first embodiment of the invention;
FIG. 6 is a sectional view illustrating a second embodiment of the invention;
FIG. 7 is a plan view illustrating a third embodiment of the invention;
~' ~ FIG. a is a sectional view of FIG. 7;
: FIG. 9 is a sectional view illustrating a fourth : 20 embodiment of the invention;
FIG. 10 is a perspective view of an immersion filter :~3~ 33~
bed with filter bed elements suspended ;
FIG. ll is a perspective view of a net tube as a L`:irst example of net-shaped substances to be used :Ln the invention ;
FIG.'12 is a perspective view of a flat net tube as another example of net-shaped substances ;
FIG. 13 is a front view of a fishing net as another example of net-shaped substances ;
FIG. 14 is a front view of a net sheet as another example of net-shaped substances ;
FIG. 15 is a front view illustrating an example of f`ilter becl elements to be used in the invention ;
FIG. 16 is a front view illustrating another example of filter becl elements ;
: FIG. 17 is a front view illustrating another example of filter bed elements ;
; FIG. 18 is a f'ront vieW illustrating another example of filter bed elements ;
FIC. 19 is a front view illustrating another example of filter bed elements ;
F'IG. 20 is a front view illustrating another example of filter bed elements ;
FIG. 21 is a perspective view il.lustrating an example of water wheels to be used in the invention ;
FIG. 22 is a perspective view illustrating another example of water wheels ; and FIG. 23 is a perspective view illustrating another example of water wheels.
In an embodiment shown in FIGS. 1 - 3, a water wheel 3 is fixed horizontally on upper ~ide of a treating tank 1, a circulation partitioning plate 2 is installed from position just below a water raking-out member 6 of the water wheel 3 towards the bottom of the traating tank 1 and spaced from the bottom of the treating tank 1 by a gap being about 10 - 30%
o~ the longitudinal length of the circulation partitioning plate 2, and water raked out by the water raking-out member 6 during rokation of the water wheel 3 cannot be returned through a gap between the water wheel 3 and a tank wall due to a xeverse flow inhibiting plate 8 to prevent the returning. Also the water cannot be returned through a small gap between lower side of the water wheel 3 and the top of the circulation partitioning plate 2 due to water urged one by one by the raking-out member 6 being rotated while the water wheel 3 is rotated. Consequently, ince the water level is elevated at receiving side o~ the raked-out water and lowered at delivering side of the raked-out water, the raked-out water is returned through an opening at the bottom of the cir~ulation partitioning plate 2 thereby ~irculation flow 7 i~ produced within the tr~ating tank 1. A number of filter bed elements 4a, 4b are installed on one side of the circulation partitioning ~3~33~
plate 2 in the treating tank 1 and spaced from each other by a def`inll;e di.stance corresponding to the sewage load ,so as to constitute an immersion filter bed 4.
In this constitution, the contact oxidation i9 perfOr'me( repeate(lly by the circulation flow.
Position of installing the imrnersion fi:Lter bed 4 in the treating tank 1 is not limited to the above-mentioned position, but the immersion filter bed 4 may be formed on both sides of the circulation partitioning plate 2 as shown in ~IG. 4 (suitable for the sewage treatment at relatively :low concentration), or a plurality of water wheels 3 may be :installed on both sides in the treating tank 1 and the immersion filter bed 4 may be provided between the circulation partitioning plate 2 on both sides as shown in FIG. 5 (suitable for the sewage treatrnent at high concentration requiring much circul.ation flow 7 by aeration).
In FIG. 6, the treating tank 1 is made deep and the circulation partitioning plate 2 is made long, thereby the treating tank 1 with large capacity at small inst.allation area may be formed (very effective at little space). In the case of` the sewage of high concentration, if the mounting number of water wheels is limited due to the installation space and the quantity of the circulation flow 7 by aeration seems little, the quantity will be increased by increasing the rotational speed of the water wheels. However, if more quantity is required, as shown in FIG. 6, auxiliary aeration ~3~
may ~e performed at side without installation of the 3mmersion filter bed 4 using an air scattering tube 25, or a circulating pump 26 may be installed and water sprinkling aeration be performed to side where water is raked out by the water wheel 3 thereby the circulation flow rate is increased and the deep shaft system can be perf`ormed.
The circulating pump 26 may be an water-immersible propeller pump or a vertical pump being a pump of larger water amount at low lift and having energy saving property and much outgoin~
amount.
Ne~t, installation mode of the filter bed elements 4a, 4b to the treating tank will be described.
The filter bed elements 4a, 4b may be vertically instaLled in parallel to the circulation partitioning plate 2 as shown in FIGS.1 - 6, vertically installed in perpendicular to the circulation partitioning plate 2 as shown in FIGS. 7 - 8, or horizontally installed in perpendicular to the circulation ~artitïoning plate 2 as shown in ~IG. 9.
Ihe installation method in FIG. 9 is suitable for tertiary treatment of the sewage of low concentr1ation and purification of water of little load such as orginal water in a water supply business, but the vertical installation with a definite spacing is preferable in the case of the sewage treatment of medium or high concentration.
~3(~Z33~
Installation of the filter bed elements lla to the treatil1g tanlc I may be performed by fixing them one by one to the ~re.lting tank 1, but as shown in FIG. 3 and F'IG. 7, method of installing slide frames 22 to the treating tank 1 and fitting the filter bed elements 4a thereto by falling is simple and prefer7able. When the filter bed ele~lents 4a are installed horizontally as shown in FIG. 9, the filter bed elements 4a may be supported by a receptable 23 of lack type.
~ s shown in FIG. 10, when the filter bed elements 4b each mounted through an upper support bar 18a are fitted respectively to a number of slits 21 of a filter bed element suspending frame 20 and hung down so as to constitute the immersion filter bed 4, the filter bed element suspending frame 20 may be supported by a receptacle support tool 24 attached to the treating tank 1 as shown in FIG. 8.
In a method that a net~shaped substance 5 such as a cylindrical net tube 5a (FIG. 11 ), a flat net tube 5b (FIG.
12), a fishing net 5c (FIG. 13) or a net sheet 5d (FIG. 14) is used as basic member of the filter bed element 4a and spread on a filter bed element support frame 17, four ends of the net-shaped substance may be fixed using pressing plates, screws or the like, the net-shaped substance may be wrapped to the frame 17 and bonded, or the net-shaped substance may be fi~ed to the frame 17 using string-shaped substance such as wire by knitting.
Concrete modes of the installation are shown in - .~ ~
13~3~39 tIGS. 15 - 17.
FIG. 15 shows an example of the filter bed e:lement 4a where the net-shaped substance 5 is mounted to the f`ilter bed element support frame 17 ;
FIG. 16 shows another example of the filter bed element ~la where the net-shaped substance 5 is mounted to the filter bed element support frame 17 at a definite spacing ; and FIG. 17 shows still another example of the filter bed element 4a where the net-shaped substance 5 is mounted to the filter bed element support frame 17 at cross Zig-Zag form.
In the case of the filter bed element 4b of suspension type, as shown in FIGS. 19 - 20, the net-shaped substance 5 is wrapped and returned on the upper support bar 18a with notched portions 27 provided on both ends, and the contact part is bonded or bound by knitting using a string-shaped substance such as wire or fixed using a pressing plate and a screw. The lower end of the net-shaped substance 5 is mounted to the lower support bar 18b in similar manner to the upper end.
Concrete modes of the installation are shown in I~IGS. 18 - 20.
FIG. 18 shows an example of the filter bed element 4b where the net-shaped substance 5 is installed to the filter bed element support bars 18a, 18b throughout the whole surf`ace ;
_ 9 _ .
~3C~t33~
FI~. 19 shows another example of the filter bed element 4b where the net-shaped substance 5 is installed to the fllter becl element support bars 18a, 18b at a definite spacing ; and FIG. 20 shows still another example of the f:ilter bed element ~b where the net-shaped substance 5 is installed to the filter bed element support bars 18a, 18b at Zig-Zag lattice form.
The filter bed support frame 17, the suspension frame 20 and the filter bed element support bars 18a, 13b are prefer-ably made of iron or stainless steel on account of workability t strength and low cost. The lower support bar 18b serves also as a weight.
The net tube 5a has diameter of 5cm - 20cm, thicl~ness of the net element wire 16 being 5mm - 10mm, and size of each mesh being about 30mm - 80mm. Since the net tube 5a is of pipe form, it is stout and suitable for ~he treatment at h:igh concentration. The flat net tube 5b is 5cm - 20cm wide and 5mm - 15mm thick, and has thickness of the net element wire being 0.5mm - 2mm and size of each mesh being about 3mm -15mm. Even when the ret of the flat net tube 5b is composed of the thin element wires 167 it has strength on account of double structure due to the flat pipe form. The fishing net 5c preferably has thickness of the element wire 16 being 2mm -4mm and size of each mesh being about 20mm - 60mm.
The flat net tube 5b is better from the viewpoints of strength, ~3~
amoul1t of` the ~naterial in use, price and machining into the f`i.lter bed elelnents 4a, 4b during the net manufacturing, and can be manuf`actured in mass production by extrusion molding and ha3 strength even using the thin element wires 16 and can be used widely for the treatment of the sewage frorn low concentration to high concentration. Since a nun1ber Or the net tubes each being as narrow as 5cm - 20cm are set to the filter bed elements 4a, 4b, each tube is independent and can be flut;~;ere(l even by pressure of the water flow and the contact eff`iciency to the microorganisms is increased corr1esponding to the movement even if it is slight.
~; Next, modes of water wheels to be used in the inventlon are shown in FIGS. 21 - 23.
FIG. 21 shows an example of the water wheel where the water raking-out members 6 are of plate form ;
FIG. 22 shows another example of the water wheel where the water raking-out members 6 are of tubular form ; and FIG. 23 shows still another example of the water wheel where the water raking-out members 6 are of comb-like for-m extending radially.
Use modes in the above-mentioned embodiments will now be described.
In the invention, the energy-saving water wheel of , low speed rotation (peripheral speed of 30 - 60 m/minute) rakes out the large water quantity throughout the overall len~th of the raking-out members 6 of the water wheel, and !
~3~"483~
the c:irculation flow 7 of the large water quantit~ by aerat:Lon is produced from the circulation partitioning plate 2 clS the borcler for the contact oxidation. In this constitution, the circulation f`low rate is significantly large in comparlson to that by an air lift, and therefore the circulation water paths large in number and width are required and the dead space ~; of the immersion filter bed 4 becomes little, thereby the contact efficiency to the microorganisms becomes well corres-pondingly.
If the ralcing-out member 6 of the water wheel is formed by a porous plate or a porous tube with large surface area, during the rotation~ a thin water film is dropped on the sur~ace of the raking out member 6 and exposed to the air thereby oxygen in the air is dissolved in the water.
On the contrary, since organic substance in the water is radlated into the air by the exposure, the substitution action can be effected although it is impossible in the aeration using a blower or a compressor.
~, 'I'he net tubes 5a, 5b and the net sheet 5d as basic substance for the filter bed elements 4a, 4b of the immersion f`ilter bed 4 to be used in,the invention can be manufactured in mass production at low cost as extrusion molding products of polyethylene resin or polypropylene resin, thereby the net tube having the net element wire 16 being thin or thick and the mesh being fine or coarse can be freely selected depending on the sewage load, Even if the resin net is broken at one ~L3~4~
position, the breakage is not spread. The resin net is used also as a net for stopping sand and is very strong, and the water flow can pass in any direction horizontally and vertically due to the mesh structure and the contact efficiency is well.
Respective spacings of the filter bed elements 4a, 4b are selected to 30mm - lOOmm depending on the water load to be treated, i,e., the contact area load. In the case of the sewage treatment at low concentration, since the contact area load is llttle, the contact area is required rnuch and therefore the net-shaped substance 5 with fine mesh is used and the filter bed elements 4a, 4b are installed at the narrowed spacing. In the case of the treatment at high concentration, since the contact area load can be taken much, the mesh may be coarse and the spacing o~ the filter bed elements 4a, 4b may be wide. Since the raw material for the mesh-shaped substance 5 is a net, the contact area per unit volume is very large.
Consequently, even if the immersion filter bed 4 is installed in a small treating tank, since the contact area is large and the circulation flow 7 subjected to aeration is much, the treating tank being very compact in comparison to other can be designed. If there is a treating tank 1 already installed, a circulation partitioning plate 2 matched to the tanlc 1 may be f~llen and fixed thereto and the water wheel 3 may be installed on upper side. In this state, if the filter bed element 4a is fallen or the filter bed element 4b of suspension 13~ 39 type ls hung, the treating tanlc 1 already instal:le(l can be r~econ3~;rlucted simply. Particularly the reconstructiorl of the standal-(l activation sludge method results in the signi.ficarlt ener~y savin~ in comparison to the blower aeration. Since the contact oxidation by the net-shaped substance 5 is perf`ormed, in the interior of the microorganism film adhered to the bed, the aerobic digestion and the anaerobic self-cligest:ion are promoted by the circulation flow 7 subjected to aeration,. thereby the excessive sludge is significantly decreassed and the treatment water quantity is slgniL`:icantly increased.
Since the filter bed elements 4a, 4b are installed in the circulation water flow paths of the treating tank 1 at a definite spacing, the closing obstruction of the lmmersion filter bed 4 as a whole cannot occur but water urged by the raking-out member 6 of the water wheel always becomes pulse flow. rhe filter bed elements 4a, 4b are oscillated by the pulse circulation flow 7, and the contact ef.ficiency between the microorganisms and the sewage is increased. In the microorganism film with the weakened activity, due to the oxygen moving by the circulation flow from the interior of the f`ilm, the activation of the aerobic bacteria is usually increased and the digestion of sludge is promoted. Natural separation occurs in a large mass from meshes of the net-shaped substance 5, and sedimentation occurs between the filter bed elelnents 4a, 4b. Since deposit to the sludge ~3~39 de~)03it portion 12 occurs, washing of the immersion filter bed 4 is no~. requir-~ed but the excessive sludge in the ~eposit portion may be regularly exhausted by a sludge exhaust tube 13.
The natural separation occurs with time lapse in some positions among a number of the net-shaped substances 5 in the immerslon filter bed 4. Since the circulation flow 7 is well, new microorganisms are immediately aclherecl to the bed where the separation occured, thereby variatlon of` the water quality due to the natural separation of the micro-organisms does not occur. Artificial treatment SUCtl as washin~
is not applied to the immersion filter bed 4 of the treating tanl~ 1at any time, but the microorganism environment is always held to the definite condition in the natural state thereby the stable treatment water can be always obtained.
If a water immersible air scatterin~ tube is arranged in place of the water wheel in each embodiment of the invention, although effects of the invention cannot be fully achieved, this constitution can be used as a water treatment device having good water treating efficiency in comparison to the prior art.
It the water wheel is omitted in each embodiment of the invention, the device can be used also as a deposit tank.
Claims (3)
1. An aeration type water treating device comprising.
a treating tank, an immersion filter bed in said tank composed of a plurality of filter bed elements each including a flat net tube as a main element, and means for vertically positioning said bed elements in parallel, a water wheel rotatably fixed on an upper side of said tank for performing surface aeration and having at least one water raking out member, a circulation partitioning plate with lower side open installed from a position just below the at least one water raking out member of the water wheel across the whole width of said tank, and means for adjusting the water level in the tank so that a part of the water raking out member is sunk in the water while circulation flow is produced from said circulation partitioning plate as the border by rotating the water wheel, said immersion filter bed being arranged at least on one side of said circulation partitioning plate.
a treating tank, an immersion filter bed in said tank composed of a plurality of filter bed elements each including a flat net tube as a main element, and means for vertically positioning said bed elements in parallel, a water wheel rotatably fixed on an upper side of said tank for performing surface aeration and having at least one water raking out member, a circulation partitioning plate with lower side open installed from a position just below the at least one water raking out member of the water wheel across the whole width of said tank, and means for adjusting the water level in the tank so that a part of the water raking out member is sunk in the water while circulation flow is produced from said circulation partitioning plate as the border by rotating the water wheel, said immersion filter bed being arranged at least on one side of said circulation partitioning plate.
2. An aeration type water treating device as set forth in claim 1, wherein said net tube is a product by extrusion of plastics.
3. An aeration type water treating device as set forth in claim 1, wherein said immersion filter bed is composed of a plurality of said filter bed elements suspended.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000538520A CA1304839C (en) | 1987-06-01 | 1987-06-01 | Aeration type water treating device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000538520A CA1304839C (en) | 1987-06-01 | 1987-06-01 | Aeration type water treating device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1304839C true CA1304839C (en) | 1992-07-07 |
Family
ID=4135792
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000538520A Expired - Lifetime CA1304839C (en) | 1987-06-01 | 1987-06-01 | Aeration type water treating device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1304839C (en) |
-
1987
- 1987-06-01 CA CA000538520A patent/CA1304839C/en not_active Expired - Lifetime
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