FIELD OF THE INVENTION

The present invention relates to waste water treatment apparatus and in particular to a modular filter system for treating liquid material to be filtered such as raw sewage.

BACKGROUND OF THE INVENΗON

Conventional trickle filter systems for water treatment involve permanent in- situ constructions usually in the form of a circular or rectangular containment tank made of concrete in which is placed treatment media such as rock or plastics material both of which provide a large surface area over which the waste water passes thereby to promote and enhance the biological processes necessary for adequate treatment; i.e. reduction in Biochemical Oxygen Demand (BOD), and chemical oxygen demand (COD).

There is a need for more operationally versatile filters, particularly in terms of easy transportability and adaptability to changing requirements.

A transportable filter is already available in the marketplace, but it is a purpose built one-piece construction being delivered to site ready for use. It, therefore, has disadvantages from the point of view of constructional versatility, being of fixed volume, handleability, cost and weight.

SUMMARY OF THE INVENTION

It is an object ofthe present invention to provide a waste water treatment filter which is of a lightweight modular construction so that it can be readily and quickly assembled and disassembled on site by hand, is substantially maintenance free and requires minimal ground preparation prior to installation.

According to a first aspect ofthe invention there is provided a panel section for use in constructing an enclosure such as a modular filter system for waste water treatment and having a front and rear face, means along opposite side edges thereof to permit one said panel section to be locked together with an abutting side edge of another said panel section in assembly, and an opening in the front face ofthe panel section leading to a pocket or compartment formed along one of said opposite side edges thereby to provide access for an operative to make a blind connection to the other one of said side edges of a said panel section held in abutting relationship therewith to lock the panel sections together.

According to another aspect ofthe invention there is provided a modular filter housing for containing waste water treatment filter media and comprising a floor formed of individual support beams disposed in spaced relationship on a ground prepared base, drainage means located between the beams to drain treated water passing through the filter media to an outlet point, containing walls mounted on the beams such as to allow access of air between the walls and floor to circulate through the filter housing the walls being formed of a series of structural panel sections, having locking channels formed along the sides thereof which are held in abutting relationship in assembly, and a locking mechanism between abutting panel sections, said locking mechanism being

activated into engagement with said opposing channels to lock the panel sections together.

Advantageously at least one side of each panel section is provided with a structurally formed pocket providing access for the use of fastening means to activate said locking piece into engagement with the locking channels.

With the present invention, almost any size of enclosure can be constructed using the modular panel sections which, at a later date, can be extended or disassembled for re-location. The modular filter housing construction avoids heavy civil engineering work, while the lightweight components used are easily manhandled on site and packed into a small volume for shipping.

BRIEF DESCRIPΗON OF THE DRAWINGS

The invention will now be described by way of example with reference to the accompanying drawings wherein;

Fig 1 shows a perspective cut away view of a modular filter housing according to the invention;

Fig 2 is a cross sectional view illustrating the installation ofthe floor ofthe modular filter housing of Fig 1;

Figs 3(a), 3(b) and 3(c) are cross sectional views of alternative embodiments of the support beams and drainage tray used to construct the floor ofthe modular filter housing;

Figs 4(a), 4(b), 4(c) and 4(d) are cross sectional views and fragmented perspective views of further embodiments ofthe floor construction ofthe modular filter housing.

Fig 5 is a cross sectional view of a panel section and corner piece forming the walls ofthe modular filter housing of Fig 1 according to one embodiment of the invention and also illustrating a cross sectional view of a link mechanism connecting one panel section to another to form the wall elements ofthe modular filter housing of Fig 1;

Fig 6 is a cross sectional view of a panel section foπning the walls ofthe modular filter housing of Fig 1 according to another embodiment ofthe invention, and also illustrating a further embodiment of a link mechanism for connecting the panel section shown in Fig 3 to another similar panel section;

Fig 7 is a cross sectional view of a still further embodiment of a link mechanism for connecting two modular panel sections in assembly; and

Fig 8 is a cut away view in perspective ofthe settlement tank for use with the modular filter housing of Fig 1.

PREFERRED EMBODIMENTS OF THE INVENΗON

The waste water treatment filter shown in Fig 1 is comprised of a base 1 and vertical side walls 2. The base 1 is constructed of a series of channel sections 3 laid in spaced relationship on prepared support walls as described later.

The inner channel sections 3', that is those channel sections between the two outer channel sections 3" are laid together in back to back relationship as shown and connected together as by bolting or welding to form a rigid combination.

As an altemative to bolting or welding the channel sections 3' to form I-beams, the outer face ofthe base of each channel section 3' may be provided with L- shaped leg formations F as shown in Fig 3(c).

When placed in a back-to-back relationship the formations may be interlocked as illustrated in Fig 3(c) as by a sliding or push fit action, to form the I- configuration desired for the floor construction ofthe modular filter housing.

Trays 4 may then be attached to the beams as before.

In Fig 3(c) there is also shown an angle support piece 21 bolted to the flange of one ofthe channel sections 3' for supporting the panel sections 22 ofthe filter housing as will more fully be described later with reference to Fig 1.

Between the assembled channel sections 3, drainage trays 4 are installed and bonded to the channels 3 to seal against the penetration of liquid.

In the embodiment shown, the trays 4 peak to an apex 5 at the centre ofthe base 1 such that filtered liquid is drained away from that central axis to prepared drainage channels 6, see Fig 2, around the perimeter ofthe base 1.

The channel sections 3', 3" are laid on support walls 7 set on concrete foundations 8 typically at 600mm centres as shown in Fig 2.

This is in contrast to the prior art wherein a concrete sump with a suitably sloped floor is first formed for draining filtered liquid to a central gully. Dwarf walls are constructed across the sump at typically 1500mm centres and redwood timber support beams are placed at 200mm centres across the dwarf walls to support the rest ofthe system.

As shown in Fig 2, so as to keep the depth ofthe channel sections to a minimum commensurate with cost, the base of each tray 4 is designed to be beneath the channel sections 3' over a portion of its length leading to the drainage channels 6 around the perimeter ofthe base 1.

So that each tray 4 is able to clear the flanges ofthe channel sections 3' when it dips beneath d e channel sections 3', the side walls 4 ¹ ofthe trays, see Fig 3a, are comprised of upper and lower portions 4", 4'" lying in parallel planes joined by an intermediate curved portion 9, the spacing between the upper and lower parallel portions being equal to the width ofthe flanges ofthe channel sections 3' as shown.

To prevent unwanted drainage through the gap between the abutting channel sections 3', a capping piece 10, preferably of glass reinforced plastics, is provided as shown.

The back to back inner channel sections 3 ¹ may be replaced by a single I-beam 11 as shown in Fig 3(b). With the use of an I-beam the need to curve the sides

ofthe trays 4 is avoided since the trays 4 with vertical side walls lying between the flanges of the I-beams 11 can be clip mounted at 12 to plastic caps 13 placed over the tops ofthe I-beam 11 as shown.

Altemative embodiments ofthe sectional floor constmction as illustrated in Figs 3(a) and 3(b) are shown in Figs 4(a), 4(b), 4(c) and 4(d) in cross sectional and fragmented perspective view.

In Fig 4(a) the tray 4 is U-shaped in cross section with the sides ofthe trays bonded to the web ofthe channel sections 3 and nesting on their bottom flanges. The channel sections 3 are bolted together at 14 as shown and provided with a capping piece 13 as before.

Instead of channel sections 3 I-beams 11 may be used, as shown in Fig 4(b) with the trays 4 bolted to the I-beams 11 as shown.

In Fig 4(c) the support beams to the floor take a split box girder form one major part 15 of which is bonded to a side of a tray 4, and the minor part 16 to the other side ofthe tray. The parts 15 and 16 are connectable along a tongue and receiving groove connection 17 to allow assembly of a floor comprising trays and support beams on site.

In Fig 4(d) concrete support beams 18 are used instead of I-beams and channels with the trays 4 suspended from the concrete beams 18 using hanging brackets 19 corresponding to the shape of the concrete beams, the brackets 19 being formed of two parts connectable along a tongued and grooved connection 20, the separable parts being bonded to respective sides ofthe trays 4.

Around the perimeter ofthe floor base 1 so formed, see Fig 1, is installed an angled support piece 21 which is bolted to the channel sections 3'.

Modular wall panel sections 22 formed typically of pultraded glass reinforced plastics are assembled along the angled support piece 21 to foπn the vertical walls ofthe filter housing, with the depth ofthe channel sections 3', 3" left exposed to allow air to enter and circulate through the system and so promote the necessary bacterial processes therein.

The filter enclosure thus assembled is filled with plastic media blocks 23 across the top of which may be placed I-beams 24 to support walkway planks constmcted in accordance with modular panel sections 22 as described below.

Each modular wall panel section 22, see more particularly in Fig 5, is comprised of a length of flat panel 25 forming the outside surface ofthe walls ofthe filter, the flat panel 25 having a series of spaced vertically depending T- shaped legs 26 integrally formed therewith.

A dove-tailed recess 27 is formed along the longitudinal edges of each panel section 22 which is used to join the panel sections 22 together, as will be explained below.

The feet ofthe last two legs 26 along one side of each panel section 22 are joined together as shown while the panel 25 between those two legs is interrupted such that a box-like pocket or compartment 28 is formed being

accessible from the outside surface ofthe panel section 22 through an aperture 29 so formed in the face ofthe panel 25.

A closure piece 30 is used to seal the aperture 29 when the modular constmction is complete and fully assembled.

To join abutting panel sections 22 together, a resilient connecting link 31 shown in Fig 5 may be employed.

The connecting link 31 is formed of a main support element 32 having side flanks 32' which taper to an apex 33 and a central aperture 34. A pair of L- shaped members 35 are hingedly connected respectively to the support element 32 with the free legs ofthe members 36 tapering to an apex 37 as shown.

The hinged members 35 are held together in the rest position, that is prior to installation and activation, by an interengageable stud 38 and cooperating recess 39.

Any two abutting modular panel sections 22 or a series of modular panel sections 22 or a comer piece 40 and a panel section 22, see Fig 5, may be fastened together using the connecting link 31. Thus, for example, the side flanks 32' ofthe connecting link 31 are first push-fit inserted into the dove¬ tailed recess 27 of a first panel section 22. A second panel section 22 or comer piece 40 is then positioned in relation to the first panel section 22 such that the respective flanges 27 are held in abutment and the L-shaped member 35 lies within the recess 27 ofthe second panel section 22 or comer piece 40.

Suitably designed studs 41 are then inserted blindly through apertures provided in the end legs 26 ofthe panel sections 22 in the accessible pocket 28 and the aligned aperture 34 in the connecting link 31 to force the hinge mounted members 35 apart whereby the tapered edges ofthe hinged members engage the opposing dove-tailed recess 27 with sealing elements 42 interposed between the respective hinged members 35 and the entrance walls ofthe dove¬ tailed recesses 27.

In the embodiment shown in Fig 5, the comer pieces 40 have along one abutting edge a dove-tailed recess 27 and along the other abutting edge, S- formations 27" complimentary to the dove-tailed recess 27 of an opposing panel section 22 for push-fit interengagement during assembly.

In Fig 6 there is shown a modified form ofthe panel section 22 of Fig 5, together with an altemative embodiment of a linkage mechanism for holding the panel sections 22 or comer piece 40 together.

In the Fig 6 embodiment, the panel section 22 is provided with a pair of spaced ribs 43 which run in parallel along the base ofthe dove-tailed recess 27. Each rib lies adjacent a comer ofthe recess 27 so that a pocket 44 with a restricted access 45 is formed at the respective bottom comers ofthe recess 27.

The link mechanism shown in Fig 6 for connecting abutting modular panel sections together is comprised of two identical elements each having a first U- shaped part 46 and a second smaller inverted U-shaped part 47 integral with one limb 48 ofthe larger U-shaped part 46.

A line of weakness 49 in the limb 48 ofthe larger U-shaped part essentially defines the transition into the curvature of the smaller U-shaped part 47 which is designed to engage the respective pockets 44 ofthe dove-tailed recesses 27 in press-fit assembly.

The inner surface ofthe free end of the limb 50 ofthe larger U-shaped part 46 has a tapered portion 51 which is designed to engage the tapered surface 52 of the walls ofthe dove-tailed recess 27 in assembly.

To fit the link mechanism so described the smaller U-shaped part 47 of each element is snapped into position in the respective pockets 44 ofthe recess 27 of a panel section 27 and a seal 53 is inserted in the base ofthe larger U-shaped part 46.

The larger U-shaped part 46 is then held away from the flange 27' of the recess 27 in which it is accommodated and another panel section 22 or comer piece 40 is brought into relationship with the first panel section until their respective flanges 27' are held in abutment.

The larger U-shaped part 46 of each of the elements of the link mechanism are then forced apart by means of a hollow dome-shaped wedge piece 54 actuated by a T-shaped turn key 55 to force the limb 50 through the restricted access 45 of the pockets 44 until the tapered surfaces 51, 52 engage and the limbs 50 fully occupy the restricted accesses 45 ofthe pockets 44.

The head 56 ofthe longer arm ofthe T-shaped turn key 55 is cπiciform in cross section, and is designed operatively to engage the hollow interior ofthe dome-

shaped wedge piece 54. To this end, an aperture 57 is provided to the interior ofthe dome-shaped wedge piece 54 for accepting the cmciform end ofthe turn key 55.

The arms ofthe cmciform end may be engaged behind the interior ledges 58 formed by the aperture 57 by turning the key 55.

By this means the turn key 55 can be engaged and disengaged from the wedge piece 54 and in the engaged position, used either to push the wedge shaped piece 54 between the larger U-shaped portions 46 ofthe link elements to force the free limbs 50 thereof into the comer pockets 44 ofthe dove-tailed recesses 27 or to withdraw the wedge piece 54 allowing the larger U-shaped portions 46 to snap back and permit separation ofthe panel sections 22.

A further form of link mechanism for connecting abutting modular panel sections is shown in Fig 7.

With this altemative constmction, none ofthe working parts ofthe locking mechanism projects from the locking channels or recesses along the sides ofthe modular panel section 22 prior to assembly as happens with the Fig 5 and 6 embodiments.

The locking channels or recesses 59 of the modular panel sections 22 in the embodiment of Fig 7 are generally U-shaped in section, having a restricted entrance formed by longitudinal flanges 60, the forward faces 61 of which slant inwardly so that in the abutting relationship ofthe panel sections as shown, a V-shaped groove 62 is formed.

Part-circular grooves or recesses 63 are formed in the locking channels behind the flanges 60.

The locking mechanism is formed of two articulateable elongate locking members 64 made of resilient material and a cooperating elongate wedging piece 65.

One of the locking members 64 with half of the wedging piece 65 in the illustration shown is in the pre-locking rest position and the other ofthe locking members 64 with the wedging piece 65 in the forward locking position for the purposes of a better understanding ofthe constmction and operation ofthe locking mechanism shown in Fig 7.

Each locking member 64 is generally U-shaped in section with part circular bulbous formations 64' along the tops ofthe side walls thereof.

The outer surface of each locking member 64 between the base and one leg thereof is outwardly rounded or convex as at 64" as shown.

A concave catchment zone 66 is formed in the outer face ofthe base of each locking member 64 and a resilient convex strip 67 of sealing material is attached to the inner face ofthe base of each locking member 64.

The catchment zone 66 is delimited on one side by an arresting rib 68, being generally an extension of a side wall of each U-shaped arm locking member 64 and on the other side by a longimdinal ridge 69.

The wedging piece 65 has a base section 70 and a truncated central section 71 formed on the base to provide outwardly extended feet portions 72.

The ends 73 ofthe feet portions 72 are part-circularly bulbous as shown.

An arcuate transitional zone 74 is formed on the outer face ofthe wedging piece 65 leading from the bulbous ends 73 ofthe feet portions 72 to the top of the truncated central section 71.

The interior ofthe wedging piece 65 is configured as with a dome shaped wedge piece 54 ofthe Fig 6 embodiment so that it may be activated using the turn key 55, see Fig 6.

The locking mechanism ofthe Fig 7 embodiment is installed in the prelocking rest position prior to erection ofthe modular filter, with the locking members

64 held in press fit spring loaded engagement between the wedging piece 65 and the U-shaped channel 59 of a representative panel section 22 with the bulbous formations 64' ofthe locking members 64 located in recessess 63 of the channel 59.

In this position the bulbous ends 73 ofthe feet portions 72 ofthe wedging piece

65 are held in the catchment zones 66, the arresting rib 68 lies against the base ofthe channels 59 and the curved face 64"of the locking members 64, the arcuate transitional zone 74 ofthe wedging piece 65.

The locking mechanism is activated by pushing the wedging piece 65 with the turn key 55 forwards from its withdrawn rest position. During this movement, the bulbous ends 73 ofthe feet portions 72 ofthe wedging piece 65 slides out of catchment zone 66 over the ridge 69 to a point beyond the ridge 69 ofthe catchment zone 66, eventually positively to locate and hold the part circular bulbous ends 6q-of the other leg ofthe locking member 64 m the part circular grooves or recesses 63 ofthe channel 59 ofthe abutting panel section 22 behind the flanges 60.

In this position also as shown, the resilient strip 67 is pressed into the receiving groove 62 formed between the slanting faces 61 of the flanges 60.

The dismantling ofthe modular panel sections 22 is thereafter readily achieved by withdrawing the wedging piece 65 with the turn key 55 which in turn then withdraws the locking member 64 to its former position.

During this movement the bulbous ends 73 ofthe feet portions 72 ofthe wedging piece 65 first pass over the ridge 69 into the catchment zone 66 and thereafter the bulbous ends 73 bears against arresting rib 68 to retum the locking member 65 to its spring loaded rest position.

A modular settlement tank 75 for use on its own or in conjunction with the filter modular filter housing, as above described, to form a complete modular waste water plant, is illustrated in Fig 8.

This is formed of a series of inverted cones 76 supported on the ground by depending legs 77. Any number of these cone-shaped elements 76 may be joined together to provide the required base area ofthe settlement tank.

Instead of individually connected inverted cones 76, a side-by-side arrangement of V-shaped troughs (not shown) may be employed to form a representative settlement tank which cuts down on cost and time of assembly.

The perimeter wall of the assembled tanks is formed with standard vertical panels 78 joined and sealed to the base and to each other as shown. Plastic settlement media 79 are supported within the perimeter walls on the top ofthe settlement cones 76 and modular panels 78, or deflector plates 80, divide the interior ofthe tank so that incoming liquid such as from a waste water filter through inlet pipe 81 is guided through the settlement media towards the outlet 82.

Suspended solids in the treated waste water may be directed to the settlement tank from a filter ofthe types described with reference to Fig 1 are thereby encouraged to settle in each cone 76, the vertex of which is connected via piping 83 to de-sludging apparatus (not shown).

The structure ofthe modular settlement tanks as above described is such that a modular filter housing of the type described with reference to Fig 1 may be constmcted on the tank supported by simple beams and posts within the tank to form a complete modular waste water treatment plant. Settled liquid from the tank may be re-circulated through the filter enhancing the process without increasing the floor plan.

A large capacity settlement tank may be constmcted using the basic design illustrated in Fig 8.

As an example rows of cones 76 or V-shaped troughs may be built-up in pairs with walkways suspended from opposed side panels ofthe separate units.

This arrangement permits access to outlet pipe 82 of each unit for adjustment and cleaning, the settlement media 79 for periodic cleaning, and the control valve (not shown) for each inlet pipe 81.

Between the walkways, the abutting cone 76 or V-shaped troughs are joined without the need of dividing walls between the common inlet areas above.

This has the advantage that any row of cones or troughs may be individually isolated for partial maintenance without shutting down the whole system.