NZ314375A - Oil/water separator and trap apparatus with water passing through successive chambers and oil spilled from chamber weirs - Google Patents

Description

314 375 Patents Form No 5 THE PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional Number: 314375 Dated: 10 March 1997 LIPOID & BUOYANT MATERIAL SEPARATION WE, GRANT WAYNE QUINN of 188 Knights Road, Lower Hutt, New Zealand, and RAYMOND TREGURTHA of 3 Hamerton Street, Lower Hutt, New Zealand, both New Zealand citizens, hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement 31437 LIQUID & BUOYANT MATERIAL SEPARATION Background & Field of Invention This invention relates to the separation of buoyant material(s) contained in or mixed with liquids; and is particularly concerned with but not necessarily 5 confined to the provision of means for separating such as oil and grease, or greasy substances, from water.

It is known to provide, and in many instances a legal requirement to provide, oil and/or grease interceptors 10 and traps in such as commercial garages and garage or other yard areas subject to vehicle repair and maintenance/servicing and the like, and for oil and grease product handling and treatment or like areas, which may be subject to oil and grease spills and 15 require periodic washing down. The contaminated washing water being required to be discharged to a drain or drainage area and directed by way of one or more oil and/or grease interceptors or traps/sumps arranged for at least partial separation and entrapment of oil 2 0 and/or grease from the contaminated water prior to discharge of the water; the collected oil and/or grease being then periodically extracted manually or by suction pump means from the interceptor traps or sumps and dumped in an appropriate waste disposal area.

Objects of Invention An object of the present invention is to provide an improved buoyant material(s) separator and trap apparatus which is of relatively simple construction 30 requiring little or no maintenance; but which is capable of more effective separation than many known separator systems and apparatus, and provides for an effective entrapment and storage of separated material in a manner enabling recovery and re-use/re-cycling where 35 appropriate.

Another object of the invention is to provide separation 314375 and trap apparatus capable of effectively trapping larger oil spills in such as garage and like areas.

Other and more particular objects and advantages of the invention will become apparent from the ensuing description.

Summary of Invention In a first aspect of this invention there is provided separator and trap apparatus for separating out and 10 entrapping buoyant material(s) contained in a liquid mix, comprising a plurality of receiving tanks arranged and connected in series for liquid flow therethrough from a first inlet to the first receiving tank of the series and out through a discharge outlet of the last 15 receiving tank in the series, with inflow to each receiving tank being to an upper part thereof and outflow on the down steam side of liquid flow being from a lower end part of each receiving tank and with the outflow from the last downstream receiving tank 20 of the series being by way of vented duct means and a shut off valve means; there being a reservoir or containing tank located in juxtaposition with said receiving tanks and each said receiving tank having an upper spill outlet means communicating with the 25 containing tank but not with the next receiving tank(s), and each such spill outlet means being at a level below the upper edges of main wall parts of the receiving tanks and disposed so as to permit the concentrate of any buoyant material(s) accumulating at the upper 30 levels of liquid contained in each receiving tank to spill over into the common reservoir or containing tank for collection and storage.

In another aspect of this invention there is provided 35 separator and trap apparatus for separating out and entrapping buoyant material(s) contained in a liquid mix, comprising a plurality of receiving tanks arranged and connected in series for a liquid mix inflow to 314375 an upper part of a first receiving tank and outflow through connecting conduit or duct means from a lower part of the first receiving tank to the upper part of the next receiving tank of the series, and outflow from a lower part of a last tank in the series via 5 a vented duct and shut-off valve means, the or any intermediate tanks in the series likewise being arranged for liquid outflow through connecting conduit or duct means from the lower part of the preceding tank to the upper part of the next downstream tank of the 10 series; each receiving tank of the series being provided with spill outlet means positioned in an upper wall part not connecting with a next receiving tank and with the spill outlet means below the uppermost edges of the main wall parts and communicating with a 15 reservoir or trap for receiving and storing the concentrate of any buoyant material(s) floating to and collecting at the liquid upper level in each tank and spilling over or through said spill outlet means with continuing flow of liquid through the receiving 20 tanks.

In a further aspect of the invention the apparatus includes an integral or separate filter and/or silt or sludge trap (eg a sump or tank) at the upstream 25 or inflow side of the first receiving tank, to which the contaminated liquid is first directed for entrapment of heavy solids and/or trash prior to supply of the main body of liquid mix to the receiving tanks. Optionally a plurality of the trap/sump tanks for 30 primary collection of contaminated liquid can be provided in spaced relationship and arranged for direct or indirect passage of the contaminated liquid collected thereby to the first receiving tank.

In a preferred aspect of the invention the apparatus is particularly arranged, constructed and adapted for use as oil and grease interceptor and trap for separating out and storing oil and/or grease, or oily/greasy substances contained in water.

The invention further includes the methods of intercepting and separating buoyant material(s) such as oil and greasy or oily/greasy substances from 5 contaminated liquid, and storing such separated material(s) as hereindescribed.

The Drawings Some preferred aspects of the invention will now be 10 described and with reference to the accompanying diagrammatic drawings, in which: FIGURE 1 is a part broken plan view of first apparatus in accordance with the invention; FIGURE 2 is a longitudinal sectional view of the apparatus of figure 1, at line II-II; FIGURE 3 is a cross sectional view of the apparatus of figures 1 and 2, at line III-III; FIGURE 3a is a fragmentary perspective enlargement of the encircled part A of figure 3; FIGURE 4 is a diagrammatic plan view illustrating an 2 5 alternative main separator assembly and a layout with a number of spaced separate primary contaminated liquid and sludge and/or silt traps for directing the contaminated liquid to the main separator assembly. 3 0 FIGURE 5 is a part broken side view of the alternative form of the main separator assembly, as seen in the direction of arrows V-V of figure 4; FIGURE 6 is a sectional view of the alternative main 3 5 separator assembly of figures 4 and 5; as viewed on line VI-VI in figure 4; 31437 314375 FIGURE 7 is a partial sectional view as viewed on line VII-VII in figure 4, of the main separator assembly, and, FIGURE 8 is a part broken side view of an outlet safety 5 trap assembly for the last receiving tank incorporating stop means effective according to the quality/oil and grease contamination at the last receiving tank outlet.

Description The following description applies to the preferred application of the invention as an oil and grease interceptor and trap for use in such as garages and other areas of operation where oil and grease spills (usually only small quantities of spillage but possibly 15 subject to the occasional larger spill) may commonly take place and frequent washing down with clean water is necessary. Many local authorities do in fact have by-laws or regulations specifically requiring the emplacement of oil and grease interceptors or 20 traps/sumps to provide at least some measure protection against the contaminated run-off water directly entering rain water systems and drains or steams; and the commonly employed oil and grease trap systems each employ one or more oil/grease trap sump or tanks for 25 receiving the contaminated run-off water - the oil/grease content settling and collecting at surface level where it is periodically syphoned or sucked off, with the (partially) cleaner water being discharged from the lower part of the trap sump(s) or tank(s).

Referring firstly to the construction according to figures 1,2,3 and 3a of the drawings, in the present invention a series of similar receiving tanks 2 are provided and inter-connected and (whilst separately 35 formed receiving tanks 2 can be employed) a unitary assembly, generally indicated by the arrow 1, is 314375 preferably provided for economy in manufacture and simplification of installation. The assembly 1 can be primarily of sheet metal construction, but is preferably formed (such as by rotational moulding, or other suitable known techniques) from strong durable 5 plastics materials providing for lightness in weight and facilitating handling transport and fitment. Fibre reinforced plastics can be alternatively employed for at least a major part of the assembly 1.

The assembly 1 is of generally rectilinear form with, in the exampled formed, three similarly sized receiving tanks 2a, 2b, 2c, located in series with common vertical transverse dividing walls 3,4 between the first (upstream) and middle receiving tanks 2a, 2b and between 15 the middle and last (downstream) receiving tanks 2b, 2c. A similar or smaller sized sludge and silt trap tank or sump 5 can be integrally formed as part of the assembly, as shown, with a common transverse vertical wall 6 between it and the first receiving 20 tank; or one or more separately formed sludge and silt trap(s) can be provided upstream of the first receiving tank 2a.

The or each sludge an/or silt receiving tank 5 is 25 preferably provided with an overflow outlet 5b which may be directed to such as a drainage pond or any main drainage sewer system to accommodate excess water which may enter the assembly and exceeds the optimum prescribed level at which the assembly 1 is designed 30 for effective separation operation. Generally the excess overflow will be clean or relatively clean water arising from such as heavy rain conditions and/or an over supply of area flushing water. if necessary in some circumstances, discharge pump means can be directly 35 or indirectly connected to the overlow outlet 5b, and directional control valve means provided to direct the overflow water/liquid to a holding tank or the 314375 like for re-cycling through the assembly 1 if the overflow water or liquid appears too contaminated for discharge to a main sewer or drain. Where the system provides for a holding tank system provides for a holding tank and re-cycling as mentioned, the pump 5 means for re-cycling preferably includes an electric motor which can be actuated by automatic or manual electrical switch means with automatic recycling operations being effective on the silt or sludge tank liquid content falling below a prescribed level.

The assembly 1 further defines an integral oil collection and storage reservoir 7 located in juxtaposition alongside the receiving tanks 2a, 2b, 2c and also in the illustrated form alongside the 15 integral sludge and silt trap 5 - although this latter location is not important. The oil reservoir 7 is defined by vertical end walls 8 and 8a of the assembly, one longitudinal vertical outer side wall 9 (the opposite longitudinal outer side wall 10 of the assembly 20 being a common outer wall for the three receiving tanks 2 and sludge/silt trap 5) and an inner longitudinal vertical wall 11 common to the reservoir 7, receiving tanks 2 and sludge/silt trap 5. The assembly 1 having a common integrally formed base 12 and an upper closure 25 lid or cover 13. For a smaller sized assembly 1 a single removable or hinged lid or cover 13 can be provided to cover and close in at least the receiving tanks 2a, 2b, 2c but preferably also the oil reservoir 9 and sludge/silt trap 5 when part of the assembly 30 1. For larger constructions the lid or cover 13 can be in separately hinged or removable parts and/or be provided with detachable or openable inspection or access hatches 14.

The cover part for the sludge/silt trap 5 can be provided with or formed as an open grill arranged to enable oil contaminated water to run or be flushed 314375 directly into the sludge/silt trap 5 - the assembly 1 being appropriately positioned and recessed relative to the surround floor or yard and its cover 13 below or flush therewith. Alternatively the contaminated water can be directed into the upper part of the 5 sludge/silt trap 5 via a conduit 15 to the upstream end wall 8 and opening into the upper part of the trap 5; in this case it will be necessary to provide an air vent 16 in the upper part for the trap 5.

Heavy sludge and silt material(s) and heavy trash etc carried with the contaminated water will thus normally settle in the base of the trap 5, and the remaining oil contaminated water is arranged to flow from the upper part of the trap 5 into the upper part of the 15 first receiving tank via conduit 17 (or an aperture) extending through the conjoining transverse wall 6. A mesh filter 5a can be provided in the upper part of the sludge/silt trap 5 either transversely (as indicated in broken outline in figure 1) or about the 20 inflow end of the conduit 17, or a like filter provided in or upstream of the first conduit 15, to collect floating debris and prevent ingress of at least a major part of such debris to the receiving tanks 2a, 2b, 2c.

The main flow of the oil contaminated water (which can be pump assisted to maintain a steady continuous flow for improved operation and effectiveness of the apparatus) is then arranged to pass from the lower 30 part of the first receiving tank 2a to the upper part of the next (in this case the middle) receiving tank 2b and from the lower part of the middle receiving tank 2b to the upper part of the last receiving tank 2c of the series, via similar conduits 18 passing 35 through the respective dividing walls 3 and 4 - with progressive separation of oil from the water as hereinafter described; to be finally arranged to pass 31437 via conduit means 19, at the downstream end wall 8a, from a lower end part of the last receiving tank 2c to a discharge area; or to a longer term large settling tank or final filtering system prior to final discharge. The assembly 1 or apparatus further including an 5 external main shut-off valve means 20 for the discharge conduit means 19, to enable emergency shut off and containment of contaminated water in the event of a sudden substantial oil spill not readily separable from water by the assembly 1 or apparatus. Air vent 10 means 21 is also provided in the discharge conduit 19 between the downstream end wall 8a and valve means 20.

Location of the conduits 17 and 18 to the side of the 15 receiving tanks 2a,2b,2c remote from the oil reservoir 7 and weirs 23 will assist lateral flow and spill over of the oil accummulated at the upper level in each tank 2af2b,2c.

With the exception of the inner longitudinal wall 11, the vertical wall parts of the assembly all terminate at a common upper level; but parts of the common dividing wall 11 have rectangular cut away portions 22 opening to the said common upper level and providing 25 horizontal wall upper edge portions 23 below the conmon upper level of the assembly and marginally below the nominal upper level of the contaminated water filling and flowing through each receiving tank 2a, 2b, 2c; so as to define a weir part 23 over which oil collecting 30 (by virtue of its buoyancy and non-solubility in water) at such water upper level can spill and pass into the communicating oil reservoir 7. The levels of the weir parts 23 may be fixed at the same or marginally different levels according to anticipated or calculated 35 water/liquid levels in the tanks 2a, 2b, 2c as it flows through for average conditions; but in one arrangement (and as indicated in the drawings) weir level adjusting 314375 plates 23a can be vertically adjustably mounted on the respective wall parts of the common wall 11. In a further alternative construction, instead of the single cut away part 22 for each receiving tank 2a, 2b, 2c, the wall 11 may extend to the same common upper 5 level as the other wall parts; and a plurality of smaller apertures are provided in the wall 11 at the desired level(s) to similarly permit spillage of oil therethrough and into the oil storage reservoir 7. In all cases the arrangement provides for the 10 progressive cleaning and separating out of oil from the contaminated water as it passes through the assembly.

Referring now to figures 4,5,6 & 7, the assembly l1 15 is similarly of unitary rectilinear form with a series of similarly constructed first second and third receiving tanks 2a,2b,2c and adjoining oil reservoir 7; and an integral but smaller main sludge and/or silt trap or sump 51 for primary receipt of the contaminated 20 liquid for the separator' assembly 1'. Figure 4 diagrammatically illustrates a number of spaced primary sumps 5'* for first receiving and directing contaminated water/liquid to the main sludge and/or silt trap or sump 5* (which can again be separately formed and 25 positioned in spaced relationship from the first separator receiving tank 2a, if preferred); and this layout with primary sumps 5' ' can similarly apply to the first described separator assembly of figures 1,2,3 and 3a.

The divider wall 11 between the receiving tanks 2a, 2b, 2c and the oil reservoir 7 has the similar rectangular upper cut away portions defining the oil spill over weirs 23 without the level adjustment means 35 23a of figures 3 and 3a, but this can be provided if required.

The alternative assembly 1' has a flow control means 314375 for controlling and limiting the flow of liquid from the main trap or sump 5'; and this may comprise a float controlled valve arrangement 24 connected to or mounted in association with the inlet 17a of the inlet conduit or connection 17 from the main trap or sump 5' to the 5 first receiving tank 2a. In the simple illustrated form, the valve arrangement 24 comprises a substantially L-shaped or dog-leg plate valve 25 mounted in juxtaposition with the inlet 17a for pivotal movement about a horizontal axis 26 parallel with the inlet 10 17 axis, to have the lower arm part 25a of the plate valve 25 arranged for sliding engagement across the opening of the inlet 17a (positive sealing engagement being unnecessary for this application). A float arm 27 has its inner end fixed to the upper end part of 15 the other upwardly extending arm part 25b of the plate valve 25, and a buoyant float-member 28 mounted at its outer free end for upward and downward movement according to the liquid level in the first receiving tank 2a and for varying the position of the plate valve 20 -5 relative to the inlet 17a opening.

To reduce turbulence caused by flow of liquid from the main trap or sump 5' to the first receiving tank 2a and thence to the second and third receiving tanks 25 2b, 2c, the respective inlet 17a and conduits 18 can be transversely staggered in position; and the conduit 18 to the (last) third receiving tank 2c may have such as a manifold outlet 18a to spread the liquid inflow pattern.

For improved final separation of oil and/or other contaminants, the (last) third receiving tank 2c is preferably provided with filtration means; and preferably filtration means incorporating or employing 35 oil adsorbent material(s) or elements. In the illustrated example, the filtration means may comprise at least one work or like container 29 (eg plastics 314375 or wire basket form), containing at least one, but preferably a plurality of, layered filtration element(s) 29a and located in the upper part of the third tank 2c to firstly assist in confining oil to the upper level of the water/liquid in the tank 2c for spilling 5 over its weir 23 into the oil reservoir 7; and secondly for the adsorbtion of at least a significant amount of oil and/or other contaminants remain in the liquid prior to passage to the lower level of the tank 2a and discharge through its outlet or discharge conduit 10 19 and control valve 20. A plurality of similar filter basket containers 29 and can be provided in stacked or tiered relationship and the or each container is arranged for ready placement and removal for periodic replacement or washing/cleaning of the filtration 15 elements 29a, as necessary. The filtration elements can be made up as layers of any suitable filtration and oil adsorbent material(s), and preferred constructions employ natural or synthetic fibrous materials; either in mat or loose felt pad form, or 20 in fibrous knops or discrete knotty or entangled fibres in small clumps contained in porous envelope comensurate in size with the basket container(s) 29. The fibrous knops or other filtration material(s) can be of the kind treated with a water repellant substance and oil 25 adsorbency enhanced for greater effectiveness and to facililtate cleaning and re-use over lengthy periods of time.

A range of convenient size assemblies can be provided, 30 and for example assemblies of say 1000, 1500, 2000 and 2,500 litre capacity may be appropriate.

Oil collected and stored in the reservoir 7 by the weir spill over means 23 as described is not subject 35 to agitation, and thus further settling out of sludge from the collected oil can take place over a period of time; and relatively clean re-usable or recyclable 314375 oil may be extracted from the reservoir 7 such as by manually operable or controllable pump means, or by way of automatically operable pump means coupled thereto and periodically operable on prescribed oil levels being reached. If required oil from the reservoir 5 can be pumped directly to a further larger settling or holding tank, and/or through oil filtering means, for improved oil recovery.

Referring now to figure 8 of the accompanying drawings 10 in one preferred form of the apparatus, in addition to or as an alternative to a simple manual or electromechanical shut off valve 20 provided at or near the discharge outlet 19 for the last receiving tank 2c, a special safety automatically operable float 15 valve assembly (generally indicated by the arrow 30) can be provided to cut off or at least substantially reduce the flow of liquid from the last receiving tank to a mains sewer or drain in the event of there being a major oil spill with which the apparatus cannot 20 readily and quickly cope.

The illustrated form of float valve assembly includes a U-bend conduit unit 31 with a first (upstream) upwardly extending tubular leg 32 of larger diameter 25 than that of the U-bend unit 31 and second (downstream) tubular leg 33 which extends upwardly in substantially parallel relationship with leg 32. The second leg 33 has its upper end part terminating in or provided with a T junction 34 with its upper end provided with 30 a removable closure cap 35 to enable access for discharge water inspection and/or testing and a lateral branch 36 coupled to a discharge conduit for directing water from the apparatus to such as a sewer or other discharge area.

The first let 32 is arranged to house a small spherical flotation balanced float-member 37 (eg such as a weight- 414375 ed table tennis ball), and Its lower junction with the U-bend unit 31 defines a valve seat 38 on which the float member 37 can seat for closure of the communication passage of the unit 31. The upper end of the first leg 32 can be closed with an upper 5 removable cap 39 enabling access for assembly and inspection as required; and the medial part of the first leg 32 is provided with a T junction or lateral branch 40 for coupling to the last receiving tank discharge outlet conduit 19. This arrangement provides 10 that under normal operating circumstances decontaminated water flowing from the discharge outlet into the first leg 32 will fill the first leg 32 and the float member 37 will rise off its valve seat 38 and float above the branch 40 to permit free flow of the water through the U-bend unit 31 and second leg 33 to discharge through branch 36. However, in the event that the water discharged from the last receiving tank 2c is insufficiently decontaminated and still contains some oil or grease, that oil or grease will float and 20 accumulate in the first leg 32 and on accumulation will gradually force the float member 37 downwardly past the branch 40 until it approaches the valve seat 38 and is forced thereonto by the water flow from the discharge outlet conduit 19 to thus prevent further discharge through the float valve assembly 30. The float member 37 is finely balanced for marginal flotation in clear or relatively clear water but not on the surface of oil or an oil concentrate. Alternative float valve means or an electronic oil 30 or density sensitive closure valve means can alternatively be employed.

Some preferred aspects of the invention have been described and illustrated by way of example, but it 35 will be appreciated that other variations of and modifications to the invention can take place without departing from the scope of the appended claims. As 314375 previously indicated any number of receiving tanks can be provided and connected in series, and the invention is not confined to the oil interceptor and trap application exampled.

Claims (36)

WHAT WE CLAIM IS: 17 314375

1. A separator and trap apparatus for separating out and entrapping buoyant material(s) contained in a liquid mix, comprising a plurality of receiving tanks arranged and connected in series for liquid flow therethrough from a first inlet to the first receiving tank of the series and out through a discharge outlet of the last receiving tank in the series, with inflow to each receiving tank being to an upper part thereof and outflow on the down steam side of liquid flow being from a lower end part of each receiving tank and with the outflow from the last downstream receiving tank of the series being by way of vented duct means and a shut off valve means; there being a reservoir or containing tank located in juxtaposition with said receiving tanks and each said receiving tank having an upper spill outlet means communicating with the reservoir or containing tank but not with the next receiving tank(s), and each such spill outlet means being at a level below the upper edges of main wall parts of the receiving tanks and disposed so as to permit the concentrate of any buoyant material(s) accumulating at the upper levels of liquid contained in each receiving tank to spill over into the common reservoir or containing tank for collection and storage.

2. A separator and trap apparatus for separating out and entrapping buoyant material(s) contained in a liquid mix, comprising a plurality of receiving tanks arranged and connected in series for a liquid mix inflow to an upper part of a first receiving tank and outflow through connecting conduit or duct means from a lower part of the first receiving tank to the upper part of the next receiving tank of the series, and outflow from a lower part of a last tank in the series via a vented duct and shut-off valve means, the or any intermediate tanks in the series likewise being arranged for liquid outflow through connecting conduit or duct means from the lower part of the preceding tank to the upper part of the next downstream tank of the series; each receiving tank of the series being provided with spill outlet means positioned in an upper wall part not connecting with a next receiving tank and with the spill outlet means below the uppermost edges of the main wall parts and communicating with a reservoir or trap for receiving and storing the concentrate of any buoyant material(s) floating to and collecting at the liquid upper level in each tank and spilling over or 31 43 through said spill outlet means with continuing flow of liquid through the receiving tanks.

3. Apparatus as claimed in claim 1 or claim 2, wherein the incoming liquid mix is directed through an integral or separate filter and/or silt or sludge trap provided at the upstream or inflow side of the first receiving tank.

4. Apparatus as claimed in claim 1 or claim 2, wherein a plurality of silt or sludge traps for primary collection of contaminated liquid mix are located in spaced relationship to each other and the first receiving tank and are coupled thereto for direct or indirect passage of the contaminated liquid collected by said traps to said first receiving tank.

5. Apparatus as claimed in any one of the preceding claims, wherein said receiving tanks and said reservoir are integrally formed as a single unit of substantially rectilinear form, the receiving tanks being each of similar rectilinear shape and size and with a common upright inner dividing wall between adjacent receiving tanks and the reservoir being of elongate rectilinear form of similar height or depth to the height or depth of the receiving tanks and of a length spanning the conjoined receiving tanks at one side transverse to the common dividing wall(s) of the receiving tanks; there being a common upright inner longitudinal dividing wall between said reservoir and conjoined receiving tanks, a common base wall for the receiving tanks and reservoir and upper lid or cover means for the receiving tanks and reservoir.

6. Apparatus as claimed in claim 5, wherein the receiving tanks and reservoir assembly are fabricated as one from sheet metal.

7. Apparatus as claimed in claim 5, wherein the receiving tanks and reservoir are of fabricated as one from fibre reinforced plastics material. 3U37 5

8. Apparatus as claimed in claim 5, wherein the receiving tanks and reservoir are fabricated as one from a durable rigid setting plastics material by a rotational or other moulding process.

9. Apparatus as claimed in any one of claims 5 to 8 inclusive, wherein said upper lid or cover means is defined by a single lid or cover spanning all said receiving tanks and said reservoir.

10. Apparatus as claimed in any one of claim 5 to 8 inclusive, wherein said upper lid or cover means include a separate lid or cover for the reservoir and a separate lid or cover for either each or all of the receiving tanks.

11. Apparatus as claimed in any one of claims 5 to 8 inclusive, wherein said lid or cover means comprise a fixed cover part for the receiving tanks and reservoir and separately hinged or removable cover parts enabling inspection of and/or upper access to the individual receiving tanks and reservoir.

12. Apparatus as claimed in any one of claims 5 to 11 inclusive when dependent upon claim 3, wherein said filter and/or silt or sludge trap is defined by an integrally formed trap tank having an inner upright wall part common to at least an upper part of the upstream or inflow side of the first receiving tank, the upper side of the trap tank being in substantial alignment with the lid or cover means for the receiving tanks and reservoir, said trap tank upper side being optionally open or provided with a hinged or detachable cover for access to said trap tank.

13. Apparatus as claimed in claim 3 or any one of claims 5 to 12 inclusive insofar as those claims are dependent upon claim 3, wherein said silt or sludge trap is provided with a mesh filter through which incoming contaminated liquid must pass prior to passage to the first receiving tank, said mesh filter being arranged to collect floating debris and prevent passage of at least a major part of such debris to the receiving tanks. 20 314375

14. Apparatus as claimed in any one of the preceding claims, wherein an outer wall of said first receiving tank is provided in its upper end part with an intake opening or conduit for the contaminated liquid directed thereto, and said intake opening or conduit is arranged for progressive closure by float control valve means within said first receiving tank as the level of contaminated liquid received by and contained in the first receiving tank reaches a prescribed upper limit.

15. Apparatus as claimed in claim 14 and wherein float control valve is arranged constructed and operable substantially as herein before described with reference to figures 6 and 7 of the accompanying drawings.

16. Apparatus as claimed in any one of the preceding claims wherein the upper spill outlet means of each receiving tank is defined by a cut-away portion or opening at or near the upper edge portion of the respective receiving tank wall to have a lower horizontal wall edge part defining a small weir over which the buoyant liquid mix at the upper level of liquid in each receiving tank can spill into the reservoir; and there being adjustment plate means mounted in lower juxtaposition with each said cut-away portion or opening for vertical adjustment as required relative to the respective lower horizontal edge wall part to set the effective spill over weir height for each receiving tank to a prescribed upper level.

17. Apparatus as claimed in claim 12, or any one of claims 13 to 16 insofar as those claims are dependent upon claim 12, wherein the integrally formed receiving tanks, reservoir and silt or sludge trap, are arranged and constructed substantially as hereinbefore described with reference to figures 1 to 3 of the accompanying drawings.

18. Apparatus as claimed in claim 12, or any one of claims 13 to 16 insofar as those claims are dependent upon claim 12, wherein the integrally formed receiving tanks, reservoir and silt or sludge trap, are arranged and constructed substantially as hereinbefore described with reference to figures 4,5 and 6 of the accompanying drawings. 314375

19. Apparatus as claimed in claim 3 or claim 4, or any one of claims 5 to 18 when dependent upon claim 3 or claim 4, wherein the or each silt or sludge tank is provided with an overflow outlet and conduit means coupled or directed to a receiving or discharge area for the accommodation of excess water flowing to the or each silt or sludge tank and prevention of excess water flow to the receiving tanks.

20. Apparatus as claimed in claim 3 or claim 4, or any one of claims 5 to 18 when dependent upon claim 3 or claim 4, wherein the or each silt or sludge tank is provided with an overflow outlet and conduit means coupled to a holding tank for the accommodation of excess water and/or contaminated liquid flowing to the or each silt or sludge tank and prevention of direction flow of the excess water and/or contaminated liquid to the receiving tanks; and there being pump means coupled to said holding tank for recycling, if and when required, of the water and/or contaminated liquid in the holding tank back to the silt or sludge tank(s), or for subsequent discharge of the holding tank contents.

21. Apparatus as claimed in claim 20 wherein said pump means includes an electric motor and the apparatus incorporates automatic or manual electrical switch means for actuation of said motor and pump means, with automatic recycling operations becoming effective on the liquid content in the silt or sludge tank(s) falling below a prescribed level.

22. Apparatus as claimed in any one of the preceding claims wherein the main flow of liquid through the series of receiving tanks is assisted and controlled by pump means to maintain a steady continuous flow for improved operation and effectiveness of the apparatus.

23. Apparatus as claimed in any one of the preceding claims, wherein a pump means is coupled to the reservoir for periodical discharge of the reservoir content to a further larger settling or holding tank and/or directly through oil filtering and recovery means where the apparatus is arranged to receive and separate oil contaminated water. 314375

24. Apparatus as claimed in any one of the preceding claims and arranged particularly for oil and/or grease contaminated water separation, wherein the last receiving tank in the series is provided with at least one filtration means located below the upper spill outlet means of the last receiving tank and through which incoming liquid must pass for further separation of oil grease or other solid/buoyant materials contaminants or substances prior to passage of the remaining filtered liquid through the discharge outlet of the last receiving tank.

25. Apparatus as claimed in claim 24, wherein said nitration means includes a plurality of horizontally disposed filtration elements extending over substantially the full horizontal area of the last receiving tank and in tiered or layered relationship; said filtration elements being removably supported to enable periodic replacement and/or cleaning.

26. Apparatus as claimed in claim 25 wherein, said filtration elements are located and supported in a plurality of openwork trays or baskets removably mounted in stacked or tiered relationship within the last receiving tank, there being at least one but preferably a plurality of the layered filtration elements provided in and supported by each tray or basket.

27. Apparatus as claimed in claim 25 or claim 26, wherein the filtration elements are comprised of oil adsorbent/materials.

28. Apparatus as claimed in claim 25, claim 26 or claim 27, wherein the filtration elements comprise or include a construction employing natural or synthetic fibrous materials.

29. Apparatus as claimed in claim 28, wherein said fibrous materials are joined in mat or loose felt pad form.

30. Apparatus as claimed in claim 28, wherein said filtration elements of fibrous materials are formed from fibrous knops or discrete knotty or entangled fibres in small 23 31437 clumps contained in porous envelopes commensurate in size with said trays or baskets.

31. Apparatus as claimed in claim 29 or claim 30, wherein the fibrous materials in loose or complete filtration element form are treated with a water repellant substance for oil adsorbency enhancement.

32. Apparatus as claimed in any one of the preceding claims, wherein said discharge outlet of the last receiving tank is coupled to a discharge conduit leading to a drain or discharge area for decontaminated water, and said discharge outlet or conduit thereat incorporates shut off valve means operable to halt liquid flow from the last receiving tank in the event of insufficient separation and/or decontamination taking place.

33. Apparatus as claimed in claim 32, wherein said shut off valve means is arranged constructed and operable substantially as hereinbefore described with reference to figure 8 of the accompanying drawings.

34. Separator and trap apparatus for separating out and entrapping buoyant material(s) contained in a liquid mix, arranged constructed and operable substantially as hereinbefore described with reference to all or any combination of the accompanying drawings.

35. A method separating oil and grease or other buoyant contaminants from a contaminated water mix, comprising the steps of: a. directing the contaminated water mix to the upper side of a silt or sludge tank for passage through first filter means into said silt or sludge tank; b. directing the contaminated water from the lower end part of the silt or sludge tank to the upper part of a first receiving tank of a series of receiving tanks arranged and interconnected to sequentially pass the liquid from the lower end part of an upstream receiving tank to the upper part of the next downstream 314375 receiving tank to discharge its content via a discharge outlet at its lower end part; c. discharging buoyant oil and grease or other buoyant contaminant collecting at the respective upper surface parts of the liquid content of each receiving tank over a spillover edge portion of a side wall of each receiving tank into an oil mix reservoir located in juxtaposition therewith, said spillover edge portion being located at a prescribed level below the upper edge portions of the respective receiving tanks and below entry levels for the incoming contaminated water mix, and spaced from the points of entry ; and d. periodically discharging part or all of the oil mix content of the reservoir either to a holding/settling tank or directly to an oil recovery means.

36. A method of separating oil and grease or other buoyant contaminants from a contaminated water mix as claimed in claim 35 and employing the apparatus according to any one of claims 1 to 34 inclusive. GRANT WAYNE QUINN & RAYMOND TREGURTHA By Their Authorised Attorneys REMMINGTON-PIPER L? C