Abstract:
A filter cloth of long pile fiber bundles is used as a tertiary filter in a wastewater processing method. The filter may be backwashed by a rotating suction head which does not touch the filter cloth. A combination of countercurrent and horizontal flow dislodges entrained solids from the filter cloth. Mounting of the filter media as modular components permits increased capacity within a single tank while avoiding down time in changeover of filter media.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of my previous application Ser. No. 10/839,166, filed May 6, 2004, which, in turn, is a continuation-in-part of Ser. No. 10/338,704, filed Jan. 9, 2003, now abandoned, the entire disclosures of which are herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to an apparatus for filtration of material such as suspended solids, from a liquid effluent. The apparatus has particular utility as a filter, particularly as a tertiary filter, in a wastewater treatment method and is particularly useful in reducing the last few ppm (parts per million) of solids in a previously treated wastewater effluent.  
         [0004]     2. Background of the Invention  
         [0005]     In my previous application, I disclosed the use of felt or pile fabric as a filter medium for a tertiary filter in a wastewater treatment process and apparatus. The use of pile fabric has become of particular interest as a filter media. A pile fabric of particular interest in this invention typically has a long-napped filter cloth or pile comprised of a plurality of fiber bundles of up to about 15 mm in length secured to a woven fiber backing. The fiber bundles, when in use, matt down to form the filter surface. Such a material has good filtering properties, but when used as a filter media, can become occluded or clogged with solid particles removed from a suspension of particles from an effluent such that the particles are retained within, and between, the fiber bundles of the filter media.  
         [0006]     It has been previously proposed to backwash a filter media comprising fiber bundles with a suction head which exerts a mechanical pressure on the leading edge of the head with an abrupt release of pressure to cause the fiber bundles to straighten abruptly within a suction slit in the suction head; See, U.S. Pat. No. 6,103,132, the entire disclose of which is herein incorporated by reference.  
         [0007]     However, such a process has various drawbacks, including low efficiency of filtering as the suction applied within the slit does not compensate for the varying surface areas of the filter to be backwashed. Furthermore, wear of the filter media by the impingement of the leading (and trailing) edge of the suction head against the filter media may also occur. In addition to wear of the fiber bundles comprising the pile, the mechanical pressure tends to pull the fiber bundles away from the woven fiber backing enlarging the apertures in the backing further resulting in loss of filtering efficiency. Still further, the filter media backing is pulled away from its supporting grid of structural material tending to stretch and misshape the filter media backing resulting in wrinkles in the filter media further impeding the movement of the suction head over the filter media. The filter media, when also subjected to mechanical pressure by the trailing edge of the suction head, also contributes to wear of the filter media. Continued use of the suction head under such conditions degrades the filter media and can pull out fibers or parts of the fiber bundles of the filter media and can even rupture the woven fabric backing resulting in premature failure of the filter media. Of course, upon failure of the filter media, the entire filtering process is disrupted, causing the filtering process to be interrupted and the filter tank in which the filter media of the prior art is contained needs to be drained, and the filter media replaced.  
         [0008]     Moreover, the arrangement of the pile filter media in the aforementioned U.S. Pat. No. 6,103,132 is mounted on a rotating shaft, with seals on the shaft about which the filter rotates. Not only do the seals leak resulting in dimunition of filter efficiency, but when the filter media fails, through either excessive wear of the fiber bundles, tear out of the fiber bundles from the fabric backing, holes in the fabric backing or, otherwise, the apparatus must be shut down, the tank in which the rotating filter is located must be drained, and the filter wheel disassembled to replace the filter media. Thus, the entire tank is taken out of commission. Furthermore, in the prior art, if one wished to increase capacity of filtering, the entire filter apparatus, including tank, and rotating filter must be duplicated when additional capacity is desired.  
         [0009]     The invention avoids all the drawbacks of the prior art filter disclosed in U.S. Pat. No. 6,103,132.  
       SUMMARY OF THE INVENTION  
       [0010]     The present invention is directed to novel filtering process and filter apparatus, including an arrangement of filter media or segments, which media does not rotate. Thus, there is no need for seals about a rotating shaft, as in the prior art, which seals may leak resulting in reduction of filter efficiency.  
         [0011]     Moreover, the filter of the invention can be subdivided into segments or modular elements that are easily inserted into, and removable from tracks permitting quick change over of filter segments or modules when replacement becomes inevitable. However, in the invention, such replacement does not require draining of the tank in which the filter sits. In addition, a single tank can be provided or installed with increased capacity achieved merely by inserting additional filters into the same tank. Because there is no cumbersome apparatus to rotate the filter media, tank clearance can be kept to a minimum while satisfying future filter capacity requirements, within a single tank. Nor is the question of overhead clearance an issue as in the prior art. As noted hereinabove, the prior art rotating filters required disassembly after draining the tank. Such disassembly required a human operator to descend into the tank to disassemble the filter media. The present invention permits the filer media to be slid out of its track, without the need to have an operator descend into the tank, and since the media may be segmented, an overhead clearance of only a few feet is necessary to permit an operator access to the filter media. Thus, when the filter apparatus of the invention is housed in a shelter or building, the overhead clearance of the building above the filter apparatus may be as little as two (2)-three (3) feet.  
         [0012]     Furthermore, my invention includes both a novel suction head which does not produce physical wear on the pile of the filter media as it does not touch the pile in the method of operating the apparatus according to my invention and a unique method of operating a filtering process.  
         [0013]     Moreover, the suction head of the invention has been designed to permit a more uniform application of suction per unit area to the filter media with the suction head being designed to exert the same, or substantially the same, degree of suction over various areas of the filter media being suctioned.  
         [0014]     Still further, the method of operating the apparatus, include reversing the rotation of the suction head between passes of the suction head over the filter media, results in more efficient cleaning of entrained solids from the filter media and an alternating orientation of the fiber bundles of the filter media such that the bundles lie in different patterns between passes. Such as been found to not only extend the life of the individual fibers comprising the fiber bundles, but also improves the efficiency of the backwashing process.  
         [0015]     The invention, thus, includes components alone, and in combination with a tank or other effluent holding container; components used in combination with one or more similar components to increase the filtering capacity of a single tank; and processes of manufacturing, installing, operating and servicing these components. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The invention will now be explained and objects, other than those set forth above, will become apparent when consideration is given to the following detailed description which makes reference to the annexed drawings herein.  
         [0017]      FIG. 1  illustrates a first side view of a filter apparatus according to a first embodiment of the invention;  
         [0018]      FIG. 2  illustrates a front view of the filter apparatus shown in  FIG. 1 ;  
         [0019]      FIG. 3  illustrates a second side view of the filter apparatus shown in  FIG. 1 ;  
         [0020]      FIG. 4  illustrates a top section view of the filter apparatus shown in  FIG. 1  showing the major components thereof;  
         [0021]      FIG. 5  illustrates a section view along line A-A in  FIG. 4 ;  
         [0022]      FIG. 6  is a face view of one embodiment of the suction head according to the invention;  
         [0023]      FIG. 7  is a back view of the embodiment of  FIG. 6 ;  
         [0024]      FIG. 8  is an end view of the head of  FIGS. 6-7  and also shows the orientation of the head with respect to a filter cloth in one embodiment of the invention;  
         [0025]      FIG. 9  is a face view of another embodiment of the suction head according to the invention;  
         [0026]      FIG. 10  is an end view of the embodiment of  FIG. 9  also showing the overturn of the head relation to the filter cloth in a manner similar to that in  FIG. 8 ;  
         [0027]      FIG. 11  is an enlarged view to show details of  FIG. 10 ;  
         [0028]      FIGS. 12   a - 12   d  are a further embodiment of the invention where filter media, together with a frame for a modular filter assembly (with upper outlet) are shown in perspective, front, right side and top views, resepctively;  
         [0029]      FIGS. 13   a - 13   d  are a further embodiment of the invention where filter media, together with a frame for a modular filter assembly (with lower outlet) are shown in perspective, front, right side and top views, respectively;  
         [0030]     FIGS.  14 ( a )-( f ) show a sequence of removing the modular filter assembly of  FIG. 13  from its position within a tank.  
         [0031]      FIG. 15  shows an embodiment for mounting the filter assemblies of  FIG. 13   a;    
         [0032]      FIG. 15   a  is an enlarged top view of the inner track assembly of  FIG. 15 ;  
         [0033]      FIG. 15   b  is an enlarged top view of the outer track assembly of  FIG. 15 ;  
         [0034]      FIG. 16  is a sectional view of an embodiment wherein multiple modular filter assemblies of  FIG. 12   a  can be used to increase the filtering capacity of a given tank;  
         [0035]      FIG. 17  is a top view of the filter of  FIG. 16 ;  
         [0036]      FIG. 18  is a section view of  FIG. 17  along lines  18 - 18 ;  
         [0037]      FIGS. 19, 20  and  21  are similar to  FIGS. 16, 17  and  18 , respectively, but shown with a lesser number of modular units;  
         [0038]      FIG. 22  is a section along lines  22 - 22  of  FIG. 20 ;  
         [0039]      FIG. 23  is a front view showing the supporting grid of modular units of  FIG. 12   a;    
         [0040]      FIG. 23B  is a cross-section of  FIG. 23 , along lines B-B of  FIG. 23 ,  FIG. 24  is a front view of  FIG. 23 , but with the filter cloth attached to the supporting grid;  
         [0041]      FIG. 24   a  is similar to  FIG. 24 , but showing the suction assembly installed,  
         [0042]      FIG. 25  is a front view of a typical modular panels of the type shown in  FIG. 24 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0043]     In one embodiment according to the present invention, a filter apparatus, such as a tertiary filter for a wastewater treatment apparatus, is provided generally shown at  100  in  FIG. 1 .  
         [0044]      FIGS. 1-4  show the general features of the filter apparatus  100 , which is generally of a box shape comprising several inner compartments. In one embodiment, the liquid to be filtered enters an upper portion of apparatus  100  via an influent pipe  1 . Inside the apparatus, the liquid is filtered to remove solids from the liquid. The cleaned liquid then passes through a discharge box  7  ( FIG. 2 ) and is discharged through a discharge port  8 . The box shape may be prefabricated from conventional materials, such as sheet metal, which may be shaped and welded into a tank. Alternatively, it may be a concrete structure, formed in situ, into which the filter apparatus of the invention is subsequently installed.  
         [0045]     According to one embodiment of the invention, as shown in  FIG. 4 , apparatus  100  is divided into three compartments, a dirty liquid chamber  2  and two clean liquid chambers  4  and  6 . A transfer pipe  5  interconnects the bottom each of the clean water chambers  4  and  5  and allows free flow of liquid between them. Filter assemblies  3 A and  3 B are mounted inside the apparatus and provide a division between dirty liquid chamber  2  and clean liquid chambers  4  and  6 . Dirty liquid entering through pipe  1  fills dirty liquid chamber  2 . The water than passes through filter assemblies  3 A and  3 B which removes solids from the liquid to clean the liquid. The clean liquid then moves into clean water chambers  4  and  6 . Clean liquid in clean water chamber  4  moves through transfer pipe  5  to clean water chamber  6 . The clean water then exits the apparatus through discharge box  7  and to discharge pipe  8 .  
         [0046]     In the alternate embodiment of  FIGS. 14   a - 14   f,  filter assembly  3 A is mounted between inner and outer tracks  145 ,  146  ( FIGS. 15   a  and  15 , respectively) of generally C-shaped configuration surrounding grid  142  ( FIG. 23 ). Grid  142  (with its attached filter cloth  141  ( FIG. 24 )) is easily removable from the apparatus  100  by withdrawing it in an upward manner along the direction of arrow  143  to remove it from an open top of apparatus  100 . It is to be understood that each of the filter cloth  141  and supporting grid can be removed in this manner without draining the dirty water  144  ( FIG. 14   e ) from apparatus  100  nor disassembling the vacuum/suction apparatus including wash arm  10 A ( FIG. 22 ) and vacuum head  220  ( FIGS. 8, 10 ,  11 ), or associated conduits  201 ,  202 . The filter assembly  3   a  may, itself, be provided with inner track  301  and outer track  302  ( FIG. 25 ) to facilitate mounting in channel  145 ,  146 . Although one embodiment is discussed in connection with the invention, it is to be understood that that discussion is equally applicable to different embodiments of the invention.  
         [0047]     In the embodiment, as shown in  FIGS. 4 and 5 , each of filter assemblies  3 A and  3 B is a divider between dirty liquid chamber  2  and clean liquid chambers  4  and  6 . Filter assemblies  3 A and  3 B comprises four grid backing plates  40  generally arranged in a circular configuration divided into four quadrants. Each backing plate  40  is removable separately from the filter apparatus to allow changing of the plates. Backing plates  40  are preferably made of a material selected from the group of plastic and metal, such as polypropylene or stainless steel.  
         [0048]     Although my earlier application disclosed that a filter  41  is located on the inside of each grid backing plate  40 , where the filter, in conjunction with a backing plate removes solids from the liquid passing from dirty liquid chamber  2  to clean liquid chambers  4  and  6 , the present invention is also directed to modular embodiments of filter assemblies ( FIGS. 12   a - 12   d  and  13   a - 13   d ) where the filter cloth  3   a  is placed on the outside, and opposing surfaces of grid  142  to create a “clean” chamber between such opposed filter cloths. Filter  141  is preferably a cloth media that is stretched over the surface of grid backing plate  142 . It may be made of a cloth polypropylene felt or a pile supported by a foraminous backing. It preferably comprises apertures of about 10 microns in width. However, any filter media capable of filtering out a desired solid may be used.  
         [0049]     The structure of each removable grid backing plate  142  ( FIG. 23 ) having an associated filter  141  mounted thereon is shown in  FIG. 24 . Each grid backing plate basically is a structural framework having filter  141  applied to a surface thereof. The combination removes desired solids from the dirty liquid.  
         [0050]     After extended use of the apparatus, the solids filtered out of the dirty liquid by filters  141  begin to accumulate, causing the filter to become clogged. To remove excessive solids, the apparatus is provided with a wash assembly  110 . Wash assembly  110  comprises a wash arm mounted on an axle  11 . The wash arm  10  is placed into near contact with filter assembly  3  and are used to wash filters  141  of such accumulated solids by either vacuuming and/or rinsing. In order for the wash arm  10  to clean the entire surface of filters  141 , the wash arm rotates about axle  11  covering the area between an inner circumference  305  and an outer periphery  307  (shown in  FIGS. 15 and 22 ). As such, wash arm  10  is mounted on axle  11  and is in fluid connection allowing for vacuum and rinsing forces to pass from filter cloth  141  through faceplate  203  into vacuum head  220 .  
         [0051]     The filter media to be placed on grid  142  is preferably a pile fabric that is stretched over grid  142  and, preferably, attached at points intermediate its periphery to grid backing plate  142 . Preferably, the filter media is made of an inert material, such as a polymer, preferably polypropylene, supported by a foraminous backing, such as a woven or non-woven fabric. The fiber bundles making up the filter media and attached to the woven or non-woven fabric can be up to 15 mm in length, although it is within the scope of the invention to use larger or shorter lengths provided that they do not substantially contact a suction head as will be described below. Suitable filter media are described in U.S. Pat. No. 6,103,132 and Netherlands Patent No. 8103750, both incorporated herein by reference in their entireties.  
         [0052]     In the embodiments illustrated in  FIGS. 12-13 , the filter media  141 , together with a supporting framework  142  may be formed into modular assemblies with a filter media (fiber side out) placed across opposite sides of the framework to form a modular filter assembly. In use, the dirty water, i.e., water containing suspended solids, is exterior of the modular filter assembly  3   a,  with the space bounded by the interior of the fabric backing and framework constituting the clean (filtered) water chamber  312  ( FIG. 19 ). The chamber  312  may be provided with at least one of a bottom outlet  313  ( FIG. 13   b ) or a top outlet  314  ( FIG. 12   a ), to extract the clean water from the chamber  312 . As with the embodiment of  FIG. 5 , the modular assemblies of  FIGS. 12-13  can also incorporate a grid backing plate  142 , optionally attached to framework  315 .  
         [0053]     The pile filter media of the present invention is, to some extent, caused to “lay flat” by the flow of effluent from the dirty to the clean (filtered) chamber.  
         [0054]     The novel suction head  200  (shown generally in  FIGS. 6-11 ) comprises a faceplate  203 , and a suction section  220  connected by one or more conduits  201 - 202 , to a source of subchamber (vacuum) pressure. As shown in  FIGS. 8, 10  and  11 , faceplate  203  is spaced away from the filter cloth  208 , such that substantially no fibers, when in their extended and erect position, are drawn into contact with faceplate  203 . In some instances, the woven or non-woven fiber backing will be drawn away (not shown) from grid backing plate  142  in a direction towards faceplate  203 . In such instances, the suction head  220  can be provided with adjustment means (not shown) such as threaded fasteners, which will permit the suction head  220  to be relatively movable towards, or away from, the filter media, so as to prevent contact with or application of mechanical pressure of either the face plate  203  or suction head  220  on the filter media  208 .  
         [0055]     Though, not wishing to be limited to the following mechanism, it is believed that the fluid flow, generally parallel to faceplate  203  (as depicted in the enlarged view of FIG.  11 ) creates a fluid (not mechanical force) between the extensions  210 ,  212  of faceplate  203  and the individual fiber bundles  314 ,  315  of filter media  208  causing the fiber bundles to release entrained or occluded solids when the flow changes from generally parallel flow (depicted by arrows  215 - 216 ) to generally perpendicular flow (depicted by arrows  217 ) as the apertures (collectively  214 ) in faceplate  203  lie over the fiber bundles  314 . As depicted schematically in  FIG. 11 , this change in flow dislodges the occluded solids from between and within the fiber bundles of the filter media  208 , permitting the particulates to enter the suction head through apertures  214  and be removed through one or more vacuum conduits  201 - 202 . The apertures  214  may be made of circular holes by drilling, boring, casting into, or otherwise when forming faceplate  203 . Faceplate  203  is preferably made of a material with no sharp edges, and can be formed of metals, including stainless steel, polymers or ceramics, although other materials, especially composites are suitable. The vacuum head assembly  200 , and especially suction head  220  is preferably made of metal, such as stainless steel, though other materials of construction similar to faceplate  203  are acceptable.  
         [0056]     Vacuum head assembly  200  is preferably mounted for rotation in relation to a fixed filter media, such as shown in FIGS.  21  or  22 . At least one vacuum head assembly  120  can be mounted on an axle attached to a post  221  ( FIGS. 15, 22 ) so as to be rotatable relative to filter media  201  ( FIG. 22 ). Suitably moved by a motor  325  and transmission device, e.g., chain  326  engaging sprocket  223 ,  323  ( FIG. 16 ) the vacuum head assemblies  200  traverse the filter media  141  in continuous or discontinuous fashion. Alternative transmission devices include toothed belts and sprockets, directly meshing gears, rack and pinion drives, hydraulic motors and pumps, and other suitable transmission means known to those skilled in the art. In a most preferred embodiment, the travel of the vacuum head assemblies  200  is controlled by function of control panel  224  ( FIG. 17 ) by either preset timer, or by monitoring means on one or more of throughput of effluent across the filter media, particulate contents of the cleaned (filtered) or dirty effluent or other process parameter such as rate of flow of effluent into (or out of) apparatus  100 ; pressure drop across the filter media, height of dirty water in the tank, etc. In a most preferred embodiment, the vacuum head assembly  200  traverses in a first (e.g., clockwise) direction and a second opposite (e.g., counterclockwise) direction between various cleaning cycles, most preferably alternate cleaning cycles.  
         [0057]     Such a sequence not only increases the efficiency of cleaning the filter media ( 3   a ), but is also thought to decrease the stress on the individual fibers comprising the fiber bundles of such media.  
         [0058]     Although the filter media  3 A can be placed on grid backing assemblies  40  ( FIG. 5 ), which separate a tank into dirty liquid chamber  2  and one or more clean liquid chambers  4  and  6  ( FIG. 4 ), the more preferred embodiment is to formulate two filter media on opposite sides of a framework  225  ( FIGS. 12   a - d  and  13   a - d ) to form the modular filter assembly  226 ,  227 .  
         [0059]     Such modular filter assemblies  226 ,  227  provide a clean (filtered) chamber  312  bonded by the framework  225  and the filter media  3   a.  If filter media  3   a  eventually needs to be replaced, not only would the tank not have to be drained and put out of commission, but one or more modular assemblies  226 ,  227  could be removed leaving the remaining modular assemblies in place and continuing to filter the dirty effluent in the single tank ( FIGS. 16-21 ). So too, this modular assembly permits increasing the filtering capacity of a single tank, e.g., such as occasioned at a later time when the demands on filtering increase, by merely inserting one or more additional modular assemblies  226 ,  227  into the same tank, e.g., compare  FIGS. 19-20  with  FIGS. 16-17 .  
         [0060]     As is apparent, modular assembly  227  has a lower outlet while modular assembly  226  has an upper outlet. It is readily apparent to those skilled in the art to whom this disclosure is directed that the modular assembly  227  having the lower outlet is depicted in an embodiment illustrated in  FIGS. 13   a - 13   d  (with connections to outlet best shown in  FIG. 19 ), where the modular assembly  226  is depicted in  FIGS. 12   a - 12   d  and  18  (with connections to outlets best shown in  FIG. 16 ).  
         [0061]     As described in my earlier applications, the filter media may be inserted into tracks or channels to position and secure the filter media within its respective tank. The same type of positioning can be achieved with modular assemblies  226 ,  227  as shown, for example, in  FIG. 15 . Therein, the modular assemblies  227  of the lower (or upper outlet-not shown) configurations can be installed between outer racks and post  221  ( FIG. 15, 15   a ). Post  221  (shown in enlarged view in  FIG. 15   a ) may comprise a rectangular tubing  233  to which are mounted first and second plates  234 ,  235 . These plates  234 ,  235  receive a right and left frame rail ( 236 ,  237 , respectively) of modular assemblies  227 ,  227 ′ to position these assemblies relative to each other; the tank and vacuum head assemblies  200  (not shown in  FIGS. 15-15   a ). However, the dotted line in  FIG. 15  depicts the vacuum head assembly  200  areas of rotation relative to the filter media  208  on each of modular assemblies  227 ,  227 ′. Further details of the mounting tracks can be seen in  FIG. 15   b.  However, these details are exemplary only and those of ordinary skill in the art will readily envision other mounting systems without departing from the spirit or scope of the invention.  
         [0062]     The vacuum head of the invention is powered by a pump  350  ( FIGS. 21-22 ) and, although it has been suggested to use a positive displacement pump in other apparatus having vacuum cleaning system as a source of vacuum, when the suction head is in direct contact with the filter media (See, U.S. Pat. No. 6,090,298 (herein incorporated by reference in its entirety)), I have found that suitable efficiencies can be obtained with a centrifugal pump as the source of vacuum to the vacuum head assemblies  200  of the invention when positioned not in contact with the fiber bundles of the filer media according to my foregoing description.  
         [0063]     In use, the filter system of my invention may be fabricated completely at a factory site, i.e., where the tank and all components are assembled together ready for shipment. Alternatively, my apparatus may be used in tanks formed in situ, or even to retrofit existing filter apparatus by removal of the rotating filters of the aforementioned U.S. Pat. Nos. 6,090,298 and 6,103,132 and inserting the modular components disclosed herein. Tracks can be provided on at least one of the tank, the modular components or filter media disclosed herein, or on both. The static positioning of the filter media in use removes the mass, and, hence, the energy necessary to rotate the mass, of prior art filtering devices. Moreover, the use of tracks or other similar mounting means permits the filters to be pulled from the tank by lifting hooks  360  as discussed, without either draining of the tank or discontinuance of the filtering process by the remaining filters. As there is no rotating filter mass within the tank, there is no need for seals, which as aforementioned, is a source of leakage in the prior art.  
         [0064]     Furthermore, the type of suction head described herein applies uniform suction per unit area to the filter media, does not exert mechanical pressure upon or cause wear of the filter media, including filter backing, and, thus, does not cause premature failure, or diminished efficiency of the filter media as in the prior art.  
         [0065]     Lastly, the alternative of applying suction in alternate directions is not possible in the prior art devices, as the leading edge is specifically constructed to apply mechanical pressure to the filter in order to make sure the apparatus is functional. Modification of this leading edge (as well as a trailing edge) to not contact the filter media has never been considered in the above-described prior art.  
         [0066]     Furthermore, fabrication of the filter media into sub-assemblies or modular components is readily accomplished at a factory, permitting the operator of a wastewater treatment plant, to maintain one or more of such filters on hand to readily interchange the filter (or modular components) without draining the tank, with little or no reduction of efficiency of the tank, and in the multiple modular component embodiment can maintain high throughout, while the other remaining components can be continuously filtering.  
       EXAMPLE  
       [0067]     The method of backwashing a stranded fiber filter media is flow reversal, i.e., a flow direction that is countercurrent to that of the flow during the filtering operation, as well as a horizontal surface scouring. Influent enters the filter through a pipe that directs the flow toward the floor of the filter. This approach uses the energy of the incoming flow to minimize settling of solids within the filter tank. The suspended solids will be removed from the flow as the influent passes through the filter media. The accumulation of solids on the media will begin to restrict the flow of fluid through the media causing the level within the filter tank to rise. When the level reaches a predetermined set point, the backwashing of the media will commence. A centrifugal pump draws fluid into the collection manifold causing the flow through the filter media to reverse and become countercurrent in the vicinity of the manifold. Flow is also generated that is horizontal to the stranded fiber as the flow is directed beneath the collection manifold; This combination of countercurrent and horizontal flow will cause the solids that have accumulated on the stranded fiber filter media to dislodge and be swept into the manifold for disposal. A drive motor that moves the manifold also engages at this time, moving the manifold past the media and collecting solids as the media is traversed. The movement of the manifold can be Bi-directional. The media is gradually exposed to an increase in the velocity of the reversing and horizontal flows until it is directly beneath the manifold, where the full effect of the combined flows remove the majority of the solids from the media. The manifold is designed so that it does not mechanically compress the media or hold it in place while traversing the filter media. This key design feature will assure maximum life of the stranded fiber filter media, as it is located above the surface and will not wear or tear the media.  
         [0068]     It is readily apparent to those skilled in the art to which this disclose is directed to modify the invention without departing from the spirit and scope of the invention.