WO2017183955A1

WO2017183955A1 - A solid removal oil recovery system (srors) for treatment of palm oil mill and related refinary raw sludge and a treatment process using said system

Info

Publication number: WO2017183955A1
Application number: PCT/MY2017/050017
Authority: WO
Inventors: Shun Bin @ Andrew Shun Bin LIEW; Seh Hian GOH
Original assignee: Liew Shun Bin @ Andrew Shun Bin; Goh Seh Hian
Priority date: 2016-04-19
Filing date: 2017-04-18
Publication date: 2017-10-26

Abstract

A Solid Removal Oil Recovery System (SRORS) for oil recovery and suspended solids removal from palm oil mill and related refinery raw sludge wherein said SRORS (1) comprises at least a holding tank (10) and into which said raw sludge is discharged and stored, a plurality of filtration assemblies or filtration modules that are connected in series, a slurry tank (11) and a decanter system (13) and with said components suitably connected. The palm oil mill and related refinery raw sludge in the holding tank (10) is subsequently transferred to the plurality of filtration assemblies for treatment, specifically cross flow filtration and with filtrate and slurry being the main products of said treatment and with said slurry transferred to the slurry tank (11). The slurry from the slurry tank (11) is fed to the decanter system (13) for oil recovery and suspended solids removal. In an embodiment of the SRORS (1), as shown in Fig. 1, four filtration assemblies are used and connected in series. In yet another embodiment, SRORS (1A) as shown in Fig. 1B, four filtration modules are used and connected in series.

Description

A SOLID REMOVAL OIL RECOVERY SYSTEM (SRORS) FOR TREATMENT OF PALM OIL MILL AND RELATED REFINARY RAW SLUDGE AND A TREATMENT PROCESS USING SAID SYSTEM

BACKGROUND TO THE INVENTION

In a palm oil mill, certain percentage of oil is lost in mesocarp fibre, empty fruit bunches, decanter cake and palm oil mill and related refinery raw sludge. This is acceptable as the existing technology presently available and practices adopted in the mill are not able to recover the lost oil. In palm oil mill and related refinery raw sludge the oil loss is in the region of 0.45 to 1.0 percent with said oil in fine droplets or in the emulsion state. Presently any amount below 1.0 percent is acceptable and considered as unrecoverable oil loss. A Solid Removal Oil Recovery System (SRORS) is forwarded by the present invention wherein the majority of the oil loss in palm oil mill and related refinery raw sludge is recoverable through treatment by a plurality of filtration assemblies connected in series, with each said filtration assembly comprises at least one filtration module, and subsequently by the decanter system. The SRORS will produce three main products which are decanter cake, oil and filtrate. The filtration assemblies within the SRORS will produce two main products which are slurry and filtrate. Typically the slurry consists of 2 to 5 percent oil, 6 to 8 percent solid and the remaining water with the exact values of the components vary from a mill to another and even over time for the same mill. The filtrate is clear brownish in colour with BOD about 25 to 35 percent of original input BOD and typically consists of water with dissolved solids and negligible amount of suspended solids and oil.

The emulsified oil in the palm oil mill and related refinery raw sludge after treatment by the plurality of filtration assemblies become part of the slurry and is channeled to the decanter system where the oil can be recovered and the solids can be removed. The filtrate from the SRORS can be discharged to existing effluent pond or tank where it can easily be treated to below 20 ppm and subsequently safely discharged into the waterways. SUMMARY OF THE INVENTION

A Solid Removal Oil Recovery System (SRORS) for treatment, mainly oil recovery and suspended solids removal, of palm oil mill and related refinery raw sludge and a treatment process using said SRORS is presented wherein said SRORS comprises at least a holding tank, a plurality of filtration assemblies connected in series, a slurry tank and a decanter system and with said holding tank, said plurality of filtration assemblies, said slurry tank and said decanter system suitably connected for process, treatment and discharge of the treated materials. The raw sludge is discharged and stored in the holding tank with said raw sludge transferred to the plurality of filtration assemblies for treatment, specifically cross flow filtration, with filtrate and slurry the primary end products of said treatment. The filtrate is safe for discharged, typically to a retention pond or a tank, while the slurry is transferred to the slurry tank. The slurry becomes progressively more concentrated after treatment by each filtration assembly of the plurality of filtration assemblies with said slurry in the slurry tank, when a desired concentration is reached, transferred to the decanter system, that can be a three phase decanter system or a two phase decanter system but not limited to such, for oil recovery and suspended solids removal.

Each filtration assembly of the plurality of filtration assemblies comprises one or more concentration tank and one or more filtration module with said concentration tank connected for discharge to said filtration module. The filtration module for treatment, specifically cross flow filtration, of sludge or slurry comprises at least a filtration unit, a feed means to feed said sludge or slurry to said filtration unit and a circulation means to circulate said sludge or slurry fed in and a discharge ducting to discharge the filtrate, after filtration, from the filtration module.

In an embodiment of the system, a plurality of filtration assemblies are used with said filtration assemblies arranged and connected in series and with said filtration assemblies being filtration assembly A, filtration assembly B, filtration assembly C and filtration assembly D. In this embodiment each filtration assembly comprises a concentration tank connected for discharge to a .filtration module. The plurality of filtration assemblies are connected in series and in a manner such that after treatment by a filtration module of a filtration assembly the slurry is transferred to the concentration tank of the next filtration assembly down line with the exception for the last filtration assembly whereby the slurry from the filtration module, after treatment, is transfer to the slurry tank. The filtrate, from treatment of slurry at each filtration module, is discharged from the system, typically to a retention pond or a tank. The treatment process, which is continuous, for oil recovery and suspended solids removal from palm oil mill and related refinery raw sludge with the SRORS comprises transferring said raw sludge from the holding tank for treatment by the plurality of filtration assemblies with filtrate and slurry being the main products of said treatment. After treatment at each filtration assembly the filtrate is drained out while the slurry is transferred to the next filtration assembly down the line for further similar treatment. At the last filtration assembly of the plurality of filtration assemblies that are connected in series, the slurry from said last filtration assembly is transferred to the slurry tank which is then transferred to the decanter system for oil recovery and suspended solids removal. Means are provided for the slurry to backflow to one or more filtration assembly/assemblies located upstream in the series to prevent overflow of any of the concentration tanks and adjust to the pumps capacities or flow or to increase its concentration before being transferred to the decanter system Likewise provision is made for the treatment process to bypass one or more of the filtration assembly/assemblies of the plurality of filtration assemblies connected in series so that maintenance or repair of one or more of the filtration assembly/assemblies can be carried out without disruption to the treatment process.

In another embodiment the concentration tanks are excluded and with the plurality of filtration modules connected in series for process treatment. Backflow from a filtration module located downstream to another filtration module located upstream is possible. Likewise provision is made for the treatment process to bypass one or more of the filtration module/modules of the plurality of filtration modules connected in series so that maintenance or repair of one or more of the filtration module/modules can be carried out without disruption to the treatment process.

It should be noted that for the sake of clarity all the components and parts of the system (SRORS) for oil recovery and suspended solids removal from and treatment of palm oil mill and related refinery raw sludge may not be shown and marked in the drawings. Additionally the terms as used in this description refer to the items as orientated in the drawings and they may in any various orientations when in use and as such the orientations as illustrated in the drawings are not necessary for operability.

The foregoing description is considered as illustration of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows the Solid Removal Oil Recovery System (SRORS) for oil recovery from and treatment of palm oil mill and related refinery raw sludge.

Fig. 1A shows the Solid Removal Oil Recovery System (SRORS) for oil recovery from and treatment of palm oil mill and related refinery raw sludge with a different embodiment for backflow.

Fig. IB shows the Solid Removal Oil Recovery System (SRORS) for oil recovery from and treatment of palm oil mill and related refinery raw sludge with absence of the concentration tanks and with the filtration modules connected in series.

Fig. 2 shows the layout of the three phase decanter system.

Fig. 2A shows the layout of the two phase decanter system.

Fig. 3 shows a filtration assembly of the SRORS.

Fig. 3 A shows the sectional view of a filtration unit of the filtration module.

Fig. 3B shows a sectional view of the filtration unit through line 'X - X' of Fig.

3A.

Fig. 3C shows a partially sectioned view of a filtration membrane unit.

DETAIL DESCRIPTION OF THE INVENTION

A Solid Removal Oil Recovery System (SRORS is designated as the short form for Solid Removal Oil Recovery System and is used throughout for its description) for treatment, mainly oil recovery and suspended solids removal, of palm oil mill and related refinery raw sludge wherein said SRORS (1) comprises at least a holding tank (10), a plurality of filtration assemblies that are connected in series, a slurry tank (11) and a decanter system (13) and with said holding tank (10), said plurality of filtration assemblies, said slurry tank (11) and said decanter system (13) suitably connected as shall be explained later in an embodiment. The palm oil mill and related refinery raw sludge is discharged and stored in the holding tank (10) with said raw sludge subsequently transferred to the plurality of filtration assemblies for treatment, specifically cross flow filtration and with the main products of said treatment being filtrate and slurry. The filtrate is drained out and discharged while the slurry is transferred to the slurry tank (11) and subsequent to the decanter system (13) for oil recovery and suspended solids removal. It should be noted that the mill existing sludge pit can also act as and serve the same purpose as the holding tank (10).

Each unit of the plurality of filtration assemblies comprises one or more concentration tank and one or more filtration module with said concentration tank connected for discharge to said filtration module. An example of a filtration assembly (20) as shown in Fig. 3, comprises a concentration tank (27) and a filtration module (21) for treatment, specifically cross flow filtration, of palm oil mill and related refinery raw sludge or slurry with said filtration module (21) comprises at least a filtration unit (24), a feed means to feed said sludge or slurry to said filtration unit (24) and a circulation means to circulate said sludge or slurry fed in and a discharge ducting (26) to discharge the filtrate, after filtration, from said filtration module (21). The filtration unit (24) further comprises a plurality of filtration membrane units (23), a casing (32) enclosing said filtration membrane units (23) with a chamber (33) formed between the external surfaces of said filtration membrane units (23) and the internal wall of said casing (32) as shown in Fig. 3A and Fig. 3B. Each filtration membrane unit (23), as shown in Fig. 3C, comprises a filter wall (31), a passageway (28), an input end (29) and an output end (30) and in the preferred embodiment said filter wall (31) is made of porous ceramic and said filter filtration membrane unit (23) comprises an unobstructed cross-section, preferably of uniform cross- section. The cross-section can be either annular, square or hexagonal cross-section but is not restricted to such. For the filtration module (21) the feed means comprises a feed pump (22) to feed raw sludge or slurry from the concentration tank (27) into the filtration unit (24) and the circulation means comprises a circulation pump (23) to circulated the raw sludge or slurry for repeat filtration by the filtration unit (24) till said slurry has reached a predetermined concentration level.

The primary end products of treatment at each filtration assembly (20), specifically by the filtration module (21) of said filtration assembly (20), are filtrate and slurry. The filtrate is safe for discharged, typically to a retention pond or a tank. For the SRORS (1) the slurry, after treatment in one filtration assembly, is transferred to the next filtration assembly down the line of the plurality of filtration assemblies that are connected in series for further treatment and is repeated for the next filtration assembly further down the line and so on until the last filtration assembly is reached whereby said slurry, after treatment, at said last filtration assembly is transferred to the slurry tank (11). The slurry becomes progressively more concentrated after treatment by the filtration module of each filtration assembly of the plurality of filtration assemblies. The slurry in the slurry tank (11), now at a desired concentration, is transferred to the decanter system (13) for oil recovery and suspended solids removal. The decanter system (13) can either be a three phase decanter system (13 A) or a two phase decanter system (13B) but not limited to such.

The primarily products of treatment in a three phase decanter system (13 A), as shown in Fig. 2 are decanter cake, decanter heavy phase and decanter light phase. The decanter cake which is basically solid, is removed and can be used for composting, for field application or similar or as animal feed. The decanter heavy phase consists slight content of oil and is channeled back to the holding tank (10) or a concentration tank for repeat treatment to maximize extraction of oil from the palm oil mill and related refinery raw sludge. The decanter light phase has a higher content of oil and is transferred to an oil recovery apparatus for oil recovery. By way of example but not limited to such, the oil recovery apparatus can be a clarifying tank (40), a disc stack centrifuge (41) which is typically an oil purifier or a sludge/oil separator or any similar apparatus serving the same purpose. When the oil recovery apparatus is a clarifier tank (40), the decanter light phase settles and separates into a layer of oil at the top and a layer of underflow at the bottom. The layer of oil at the top is the recovered oil from palm oil mill and related refinery raw sludge and is transferred to a separate or common crude palm oil tank. The layer of underflow in the clarifier tank (40) has residual oil content and is transferred back to the holding tank (10) for repeat treatment through the system When the oil recovery apparatus is a disc stack centrifuge (41) oil in the decanter light phase is separated out by centrifugal action of the equipment.

The primarily products of treatment in a two phase decanter and oil or sludge separator system (13B), as indicated in Fig. 2A but may be arranged in a different order, are oil, decanter cake and separator heavy phase. The decanter cake which is basically solid, is removed by the two phase decanter and can be used for composting, for field application or similar or as animal feed. The oil/sludge separator (42) recovers the oil. The separator heavy phase consists slight content of oil and is channeled back to the holding tank (10) or a concentration tank for repeat treatment to maximize extraction of oil from the palm oil mill and related refinery raw sludge.

In an embodiment of the SRORS (1), as shown in Fig. 1, four filtration assemblies are used with said filtration assemblies arranged and connected in series and with said filtration assemblies being filtration assembly A (14), filtration assembly B (15), filtration assembly C (16) and filtration assembly D (17), said filtration assembly A (14) comprising at least a concentration tank A (14a) connected for discharge to filtration module A (14b), said filtration assembly B (15) comprising at least a concentration tank B (15a) connected for discharge to filtration module B (15b), said filtration assembly C (16) comprising at least a concentration tank C (16a) connected for discharge to filtration module C (16b) and said filtration assembly D (17) comprising at least a concentration tank D (17a) connected for discharge to filtration module D (17b). The plurality of filtration assemblies are connected in series and a manner such that, for each filtration assembly after processing the sludge/slurry in the filtration module of said filtration assembly the resulting more concentrated slurry is transferred to the concentration tank of the next filtration assembly that is connected down line in the connected series with the exception for the last filtration assembly of said connected series, filtration assembly D (17) in this example. The treated slurry from filtration module D (17b) of filtration assembly D (17) is transferred to the slurry tank (11). In the embodiment, shown in Fig. 1, the resulting slurry from filtration module A (14b) after treatment is transferred to concentration tank B (15a), the resulting slurry from filtration module B (15b) after treatment is transferred to concentration tank C (16a) and the resulting slurry from filtration module C (16b) after treatment is transferred to concentration tank D (17a). As filtration assembly D (17) is positioned last in the connected series of filtration assemblies, the resulting slurry from filtration module D (17b) after treatment is transferred to the slurry tank (11). The filtrate, after treatment at each filtration module, is discharged from the SRORS (1), typically to a retention pond or a tank. Filtration module A (14b), filtration module B (15b), filtration module C (16b) and filtration module D (17b) can be different in capacities to match their operational requirements. The volume of slurry to be treated decreases along the series of connected filtration assemblies due to the discharge of filtrate from each of the connected filtration assembly.

Provision is provided for backflow of treated slurry from one or more filtration assembly/assemblies, specifically from the concentration tank tanks of said filtration assembly/assemblies, or from the slurry tank (11) to another concentration tank tanks of another filtration assembly/assemblies located upstream of the plurality of filtration assemblies that are connected in series. The provision can comprise pipework, pumps, valves and meters connecting the concentration tanks. Alternatively the concentration tanks can be positioned at different heights or level and having suitably located overflow outlets to permit slurry in one concentration tank to backflow, by gravity, into another concentration tank located upstream. The purpose of the provision for backflow is to increase the concentration of the slurry in the appropriate concentration tank or tanks and eventually the slurry in the slurry tank (11) before transferring said slurry to the decanter system (13) for oil recovery and suspended solids removal and also to adjust the flow to the pumps capacities. In the SRORS (1), as shown in Fig. 1, backflow of slurry from the slurry tank (11) to concentration tank D (17a), backflow of content from said concentration tank D (17a) to concentration tank C (16a), backflow of content from said concentration tank C (16a) to concentration tank B (15a) and backflow of content from said concentration tank B (15a) to concentration tank A (14a) are provided. In another embodiment of the SRORS, as shown in Fig. 1A, backflow is from the slurry tank (11), concentration tank D (17a), concentration tank C (16a) and concentration tank B (15a) into concentration tank A (14a). The provision for backflow is not restricted to the examples provided as various variations are possible and with them falling within the present scope of invention. Provision is also made for the treatment process to bypass one or more of the filtration assembly/assemblies of the plurality of filtration assemblies that are connected in series. This is so that maintenance or repair of one or more of the filtration assembly/assemblies can be carried out without disruption to the process.

It should be noted that the palm oil mill and related refinery raw sludge that is fed into holding tank (10) includes one or more of decanter heavy phase, sterilizer condensate, EFB liquor or the like. By way of example but not limitation, the palm oil mill and related raw sludge may be sludge from a sludge pit, decanter heavy phase from the mill's and said system centrifugal decanter, sterilizer condensate from sterilizer, EFB liquor, waste water from mill cleaning de-oiling tanks or any source which are deemed to be suitable to serve this oil recovery purpose.

The treatment process, which is continuous, with the SRORS (1) for oil recovery and suspended solids removal and treatment of palm oil mill and related refinery raw sludge for oil recovery wherein the steps of said treatment process comprises :- i. palm oil mill and related refinery raw sludge from the holding tank (10) is transferred to the concentration tank A (14a) of filtration assembly A (14);

ii. the sludge in concentrated tank A (14a) is discharged to filtration module A (14b) for treatment ie. for cross flow filtration and with slurry and filtrate being products of said filtration and with said slurry transferred to concentration tank B (15a) of the filtration assembly B (15) and with said filtrate drained out and discharged to a retention pond or a tank;

iii. the slurry in concentration tank B (15a) is discharged to filtration module (15b) for treatment ie. cross flow filtration and similarly with slurry and filtrate being products of said filtration and with said slurry from said filtration module B (15b) transferred to concentration tank C (16a) and with said filtrate drained out and discharged to a retention pond or a tank;

iv. the slurry in concentration tank C (16a) is discharged to filtration module C (16b) for treatment ie. cross flow filtration and similarly with slurry and filtrate being products of said filtration and with said slurry from said filtration module C (16b) transferred to concentration tank D (17a) and with said filtrate drained out and discharged to a retention pond or a tank; v. the slurry in concentration tank D (17a) is discharged to filtration module D (17b) for treatment ie. cross flow filtration and similarly with slurry and filtrate being products of said filtration and with said slurry from said filtration module D (17b) transferred to the slurry tank (11) and with said filtrate drained out and discharged to a retention pond or a tank;

vi. the slurry from said slurry tank (11) is transferred to the decanter system (13) whereby oil is recovered and suspended solids removed;

vii. the decanter heavy phase, a product from treatment by said decanter system (13), is transferred back to the holding tank (10) or a concentration tank for repeat treatment.

In another arrangement of the S ORS of the present invention a plurality of filtration modules are used with said filtration modules arranged and connected in series and the concentration tanks that were connected to said filtration modules (to form filtration assemblies) as detailed in the earlier embodiment of the SRORS (1) are no required. The plurality of filtration modules are connected in series and a manner such that for each filtration module after processing the sludge/slurry the resulting more concentrated slurry is transferred to the next filtration module that is connected down line in the connected series with the exception for the last filtration module of said connected series whereby the treated slurry from the last filtration module is transferred to the slurry tank. In an embodiment of the SRORS (1A). of this arrangement, as shown in Fig. IB four filtration modules are used with said filtration modules arranged and connected in series and with said filtration modules being filtration modules E (50), filtration modules F (51), filtration module G (52) and filtration module H (53). In this embodiment raw sludge is fed from the holding tank (10) into filtration module E (50), the resulting slurry from filtration module E (50) after treatment is transferred to filtration module F (51), the resulting slurry from filtration module F (51) after treatment is transferred to filtration module G (52) and the resulting slurry from filtration module G (52) after treatment is transferred to filtration module H (53). As filtration module H (53) is positioned last in the connected series of filtration modules, the resulting slurry from filtration module H (53) after treatment, and has reached an acceptable concentration level, is transferred to the slurry tank (11). The filtrate, after treatment at each filtration module, is discharged from the SRORS (1A), typically to a retention pond or a tank. Filtration module E (50), filtration module F (51), filtration module G (52) and filtration module H (53) can be different in capacities to match their operational requirements. The volume of slurry to be treated decreases along the series of connected filtration modules due to the discharge of filtrate from each of the connected filtration modules.

For this embodiment of the SRORS (1A) provision is provided for backflow of treated slurry from one or more filtration module/modulus or from the slurry tank (11) to another filtration module located upstream of the plurality of filtration modules that are connected in series. The provision can comprise pipework, pumps, valves and meters connecting the filtration modules. The purpose of the provision for backflow is to increase the concentration of the slurry in the appropriate filtration module and eventually the slurry in the slurry tank (11) before transferring said slurry to the decanter system (13) for oil recovery and suspended solids removal and also to adjust the flow to the capacities of the pumps. In the SRORS (1A), backflow of slurry from the slurry tank (11) to filtration module H (53), backflow of content from filtration module H (53) to filtration module G (52), backflow of content from filtration module G (52) to filtration module F (51) and backflow of content from filtration module F (51) to filtration module E (50) are provided. The provision for backflow is not restricted to the examples quoted as various variations are possible and with them falling within the present scope of invention.

Provision is also made for the treatment process of this embodiment of the SRORS (1A) to bypass one or more of the filtration module/modules of the plurality of filtration modules that are connected in series. This is so that maintenance or repair of one or more of the filtration module/modules can be carried out without disruption to the process.

The treatment process, which is continuous, with the SRORS (1 A) for oil recovery and suspended solids removal and treatment of palm oil mill and related refinery raw sludge for oil recovery wherein the steps of said treatment process comprises :- i. palm oil mill and related refinery raw sludge from the holding tank (10) is transferred to the filtration module E (50) for treatment ie. for cross flow filtration and with slurry and filtrate being products of said filtration and with said slurry, after treatment by said filtration module E (50), transferred to filtration module F ( 1) and with said filtrate drained out and discharged to a retention pond or tank;

ii. treatment in filtration module F (51) is cross flow filtration with slurry and filtrate being products of said filtration and with said slurry from said filtration module F (51), after treatment by said filtration module F (51), transferred to filtration module G (52) and with said filtrate drained out and discharged to a retention pond or tank;

iii. treatment in filtration module G (52) is again cross flow filtration and similarly with slurry and filtrate being products of said filtration and with said slurry from said filtration module G (52), after treatment, transferred to filtration module H (53) and with said filtrate drained out and discharged to a retention pond or tank;

iv. treatment in filtration module H (53) is cross flow filtration and similarly with slurry and filtrate being products of said filtration and with said slurry from said filtration module H (53), after treatment and now at the desired concentration, transferred to the slurry tank (11) and with said filtrate drained out and discharged to a retention pond or tank;

v. the slurry from said slurry tank (11) is transferred to the decanter system (13) for oil recovery and suspended solids removal;

vi. the decanter heavy phase with residual oil and a product from treatment by said decanter system (13) is transferred back to the holding tank (10) or a filtration module for repeat treatment.

It should be noted that for the sake of clarity all the components and parts of the SRORS (1, 1A) for oil recovery from and treatment of palm oil mill and related refinery raw sludge may not be shown and marked in the drawings. Additionally the terms as used in this description refer to the items as orientated in the drawings and they may in any various orientations when in use and as such the orientations as illustrated in the drawings are not necessary for operability. The foregoing description is considered as illustration of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Claims

1. A Solid Removal Oil Recovery System (SRORS) (1) for treatment, mainly oil recovery and suspended solids removal, of palm oil mill and related refinery raw sludge wherein said SRORS (1) comprises :- at least a holding tank (10) for receiving and storing palm oil mill and related refinery raw sludge;

a plurality of filtration assemblies connected in series and with each filtration assembly comprises one or more concentration tank/tanks connected to one or more filtration module/modules for cross flow filtration;

a slurry tank (11) for storage of slurry after treatment by said plurality of filtration assemblies;

a decanter system (13) for oil recovery and suspended solids removal from said slurry from said slurry tank (11);

said holding tank (10), said plurality of filtration assemblies, said slurry tank (11) and said decanter system (13) are suitably connected for process, treatment and discharge of treated materials fed into said SRORS (1);

a means to backfiow slurry from said slurry tank (11) and/or from concentration tank/tanks that are located downstream of said plurality of filtration assemblies into another concentration tank/tanks of filtration assembly/assemblies that are located upstream in said series for repeat treatment of said slurry;

a means to bypass one or more of said filtration assembly/assemblies without disrupting the treatment process.

2. A SRORS (1) as in claim 1 wherein four filtration assemblies are used with said filtration assemblies arranged and connected in series and with said filtration assemblies being filtration assembly A (14), filtration assembly B (15), module C (16) and filtration assembly D (17) and with said filtration assembly A (14) comprising concentration tank A (14a) connected for discharge to filtration module A (14b), said filtration assembly B (15) comprising concentration tank B (15a) connected for discharge to filtration module B (15b), said filtration assembly C (16) comprising concentration tank C (16a) connected for discharge to filtration module C (16b) and said filtration assembly D (17) comprising concentration tank D (17a) connected for discharge to filtration module D (17b) and with said holding tank (10) connected for discharge to said concentration tank A (14a) and with said filtration module A (14b) connected for discharge to said concentration tank B (15a), said filtration module B (15b) connected for discharge to said concentration tank C (16a), said filtration module C (16b) connected for discharge to said concentration tank D (17a) and said filtration module D (1 b) connected for discharge to said slurry tank (11).

3. A S ORS (1) as in claim 1 wherein the backflow means comprises pipework, pumps, valves and meters connecting the concentration tanks.

4. A SRORS (1) as in claim 1 wherein the backflow means comprises having the concentration tanks positioned at different heights or level and having suitably located overflow outlets and permitting slurry in one concentration tank to backflow, by gravity, into another concentration tank locating upstream.

5. A SRORS (1) as in claim 2 wherein backflow of slurry from the slurry tank (11) to concentration tank D (17a), backflow of slurry from concentration tank D (17a) to concentration tank C (16a), backflow of slurry from concentration tank C (16a) to concentration tank B (15a) and backflow of slurry from said concentration tank B (15a) to concentration tank A (14a) are provided.

6. A treatment process, with the SRORS (1) for palm oil mill and related refinery raw sludge for oil recovery and suspended solids removal wherein the steps of said treatment process are :- i. palm oil mill and related refinery raw sludge from the holding tank (10) is transferred to the concentration tank A (14a) of filtration assembly A (14);

ii. the sludge in concentrated tank A (14a) is discharged to filtration module A (14b) for treatment ie. for cross flow filtration and with slurry and filtrate being products of said filtration and with said slurry transferred to concentration tank B (15a) of the filtration assembly B (15) and with said filtrate drained out and discharged to a retention pond or tank;

iii. the slurry in concentration tank B (15a) is discharged to filtration module B (15b) for treatment ie. cross flow filtration and similarly with slurry and filtrate being products of said filtration and with said slurry from said filtration module B (15b) transferred to concentration tank C (16a) and with said filtrate drained out and discharged to a retention pond or tank;

iv. the slurry in concentration tank C (16a) is discharged to filtration module C (16b) for treatment ie. cross flow filtration and similarly with slurry and filtrate being products of said filtration and with said slurry from said filtration module C (16b) transferred to concentration tank D (17a) and with said filtrate drained out and discharged to a retention pond or tank;

v. the slurry in concentration tank D (17a) is discharged to filtration module D (17b) for treatment ie. cross flow filtration and similarly with slurry and filtrate being products of said filtration and with said slurry from said filtration module D (17b) transferred to the slurry tank (11) and with said filtrate drained out and discharged to a retention pond or tank;

vi. the slurry from said slurry tank (11) is transferred to the decanter system (13) for oil recovery and suspended solids removal;

vii. the decanter heavy phase with residual oil and a product from treatment by said decanter system (13) is transferred back to the holding tank (10) or a concentration tank for repeat treatment.

7. A Solid Removal Oil Recovery System (SRORS) (1A) for treatment, mainly oil recovery and suspended solids removal, of palm oil mill and related refinery raw sludge wherein said SRORS (1 A) comprises :- at least a holding tank (10) for receiving and storing palm oil mill and related refinery raw sludge ;

a plurality of filtration modules connected in series for cross flow filtration;

said holding tank (10), said plurality of filtration modules, said slurry tank (11) and said decanter system (13) are suitably connected for process, treatment and discharge of treated materials fed into said SRORS (1 A); a means to backflow slurry from said slurry tank (11) and/or from filtration module/modules that are located downstream of said plurality of filtration modules into another filtration module/modules that are located upstream in said series for repeat treatment of said slurry;

a means to bypass one or more of said filtration module/modules without disrupting the treatment process.

8. A SRORS (1A) as in claim 7 wherein four filtration modules are used with said filtration modules arranged and connected in series and with said filtration modules being filtration module E (50), filtration module F (51), filtration module G (52) and filtration module H (53) and with said filtration module E (50) connected for discharge to filtration module F (51), said filtration module F (51) connected for discharge to filtration module G (52), said filtration module G (52) connected for discharge to filtration module H (53) and said filtration module H (53) connected for discharge to the slurry tank (11).

9. A SRORS (1A) as in claim 7 wherein the backflow means comprises pipework, pumps, valves and meters connecting the concentration tanks.

10. A SRORS (1A) as in claim 8 wherein backflow of slurry from the slurry tank (11) to filtration module H (53), backflow of slurry from filtration module H (53) to filtration module G (52), backflow of slurry from filtration module G (52) to filtration module F (51) and backflow of slurry from filtration module F (51) to filtration module E (50) are provided.

11. A treatment process, with the SRORS (1A) for palm oil mill and related refinery raw sludge for oil recovery and suspended solids removal wherein the steps of said treatment process are :- i. palm oil mill and related refinery raw sludge from the holding tank (10) is transferred to the filtration module E (50) for treatment ie. for cross flow filtration and with slurry and filtrate being products of said filtration and with said slurry transferred to filtration module F (51) and with said filtrate drained out and discharged to a retention pond or tank; ii. treatment in filtration module F (51) is cross flow filtration with slurry and filtrate being products of said filtration and with said slurry from said filtration module F (51) transferred to filtration module G (52) and with said filtrate drained out and discharged to a retention pond or tank;

iii. treatment in filtration module G (52) is again cross flow filtration and similarly with slurry and filtrate being products of said filtration and with said slurry from said filtration module G (52) transferred to filtration module H (53) and with said filtrate drained out and discharged to a retention pond or tank;

iv. treatment in filtration module H (53) is cross flow filtration and similarly with slurry and filtrate being products of said filtration and with said slurry from said filtration module H (53), now at the desired concentration, transferred to the slurry tank (11) and with said filtrate drained out and discharged to a retention pond or tank;