WO2020049583A1

WO2020049583A1 - A system for removing floating debris in an open water channel

Info

Publication number: WO2020049583A1
Application number: PCT/IN2019/050026
Authority: WO
Inventors: Vinayakam JOTHIPRAKASH; Meena Harphool SINGH; Meena RANU
Original assignee: Indian Institute of Technology Bombay
Current assignee: Indian Institute of Technology Bombay
Priority date: 2018-09-05
Filing date: 2019-01-11
Publication date: 2020-03-12
Anticipated expiration: 2021-03-05
Also published as: ZA202102147B

Abstract

A System for Removing Floating Debris in an Open Water Channel The invention relates to a system for removing floating debris in an open water channel. The system includes a perforated screen placed between the channel walls, extends from surface of water towards bottom of the channel to impede the flow of water thereby accumulating floating debris; a float connected on the rear side of the perforated screen; an inclined conveyor belt having an upper end and a lower end; a plurality of vessels mounted on the conveyor belt at predetermined location; and means for driving the conveyor belt for moving the conveyor belt from the lower end to the upper end to collect the accumulated floating debris and moves towards the upper end, whereby the vessel while transiting from the upper end towards the lower end dumps the floating debris in a debris collector.

Description

TITLE OF THE INVENTION

A System for Removing Floating Debris in an Open Water Channel FIELD OF THE INVENTION

[001] The invention relates generally to a system for water treatment and more particularly to a system for removing floating debris in an open water channel.

BACKGROUND OF THE INVENTION

[002] Water pollution is generally referred to the presence in water of harmful and objectionable material obtained from sewers, industrial wastes and rainwater runoff in sufficient concentrations to make it unfit for use. Water pollutants arising out of said sources may be broadly classified as dissolved, suspended and floating materials. United Nations Environment Programme defines floating materials or floating debris or marine litter as ‘any persistent, manufactured or processed solid material, discarded, disposed of, or abandoned in the marine and coastal environment’. Accordingly, plastic materials, wood, leaves, synthetic fibers, leather and any other lightweight materials capable of floating are construed as floating debris. These floating debris not only cause risk to marine life from entanglement and indigestion but also cause damage to humans and cattle - affecting pristine habitats, contamination of beaches, hazardous to public health, injury to cattle grazing in coastal areas, contamination of harbours and marinas, damage to fishing vessels, damage to power stations and desalination plants, etc.

[003] Typically, an open channel drain system consists of a secondary drainage system with a network of small drains attached. These small drains bring the water to a primary drainage system, composed of main drains. Thereafter, these drains are generally connected to natural drainage channels such as rivers, streams, seas, oceans, etc. Such open channels not only receive rain water in the form of surface runoff but also receives solid waste materials in the form of floating debris which are eventually disposed in water bodies thereby polluting the water bodies. [004] In a typical water treatment process, mechanical primary treatment of water precedes biological and / or physiochemical treatment whereby floating debris is removed. In this regard, it is always beneficial to remove the floating debris from the open channel rather than allowing the floating debris to be disposed in water bodies and then removing the debris from the water bodies.

[005] Various efforts have been made in past towards removal of floating debris in an open sewage channel and water bodies. One such effort is in the form of aquatic trash skimmers which are designed for collecting and removing floating debris and are operated by a person. There are similar vessel based concepts existing in prior arts, however same require high implementation cost, high maintenance cost, high energy consumption, operator intervention, etc.

[006] Thus, there is a need in the art for an economical and low powered system for removing floating debris in an open channel which does not require an operator.

SUMMARY OF THE INVENTION

[007] Accordingly, the present invention in one aspect provides a system for removing floating debris in an open water channel having a pair of opposite, mutually parallel channel walls and a bottom. The system includes a perforated screen having a front side and a rear side placed between the channel walls, the perforated screen extends from surface of water towards the bottom of the channel to impede the flow of water thereby accumulating floating debris adjacent to front side of the perforated screen; a float connected on the rear side of the perforated screen for allowing the perforated screen to gradually rise from the bottom of the channel corresponding to water flow rate while otherwise being maintained in proximity to the bottom of the channel; a conveyor belt having an upper end and a lower end, the conveyor belt inclined between the upper end and the lower end and the lower end positioned adjacent to the front side of the perforated screen; a plurality of vessels mounted on the conveyor belt at predetermined locations; and means for driving the conveyor belt for moving the conveyor belt from the lower end to the upper end whereby the vessel towards the lower end collects the accumulated floating debris and moves towards the upper end, the vessel while transiting from the upper end towards the lower end dumps the floating debris in a debris collector. A tray is provided adjacent to the upper end of the conveyor belt to collect debris which is dumped from the vessels. The perforated screen and the vessels have plurality of holes wherein diameter of the holes is in a range of 10 mm to 20 mm.

[008] In an embodiment of the invention, a first frame is provided. The first frame having: a first pair of vertical, spaced apart, mutually parallel rigid members mounted on one of the channel wall and a second pair of vertical, spaced apart, mutually parallel rigid members mounted on the other channel walls and opposite to the first pair of the vertical rigid member; a horizontal rigid member having a first side end and a second side end extending between the first and the second pair of the vertical rigid members; a roller mounted on each side ends of the horizontal rigid member and engageable between the respective pair of vertical rigid members, the roller configured to move between the vertical rigid members thereby moving the horizontal rigid member in a vertical direction; at least one lateral, rigid member extending from the horizontal rigid member; and at least one float fixedly mounted on the lateral rigid member, the float tend to move back and forth in a substantially vertical direction in response to water flow rate causing the horizontal rigid member to move in vertical direction.

[009] Yet, in another embodiment of the invention, the frame has plurality of the lateral rigid members, each of the lateral rigid members connected to rear side of the perforated screen; and plurality of floats fixedly mounted on the lateral rigid members, the floats tend to move back and forth in a substantially vertical direction in response to water flow rate causing the horizontal rigid member and thus the perforated screen to move in vertical direction.

[010] In a further embodiment of the invention, a second frame is provided having a pair of vertical rigid members, each of the vertical rigid members mounted on opposite channel walls; and a horizontal rigid member having a first end and a second end, the horizontal rigid member extending between the pair of vertical rigid members. The upper end of the conveyor belt is connected to the horizontal rigid member of the second frame.

[011] In an additional embodiment of the invention, bearing means are connected at end of both sides of horizontal rigid member, which permit rolling of the horizontal rigid member on the vertical rigid members.

[012] In another embodiment of the invention, an inclined support is provided, the inclined support having an upper end and a lower end, the upper end fixed to the horizontal rigid member of the second frame.

[013] In a further embodiment of the invention, the system includes a float mounted on the horizontal rigid member and placed between a pair of floats mounted on the horizontal rigid member and an elongated member extending from the first frame and connected to the lower end of the conveyor belt or to the lower end of the inclined support.

BRIEF DESCRIPTION OF THE DRAWINGS

[014] Figure 1 is a schematic representation of the system in accordance with an embodiment of the present invention.

[015] Figure 2 is a schematic representation of the system in accordance with an embodiment of the present invention.

[016] Figure 3 shows a front view of the perforated screen in accordance with an embodiment of the present invention.

[017] Figure 4 shows a barrier unit in accordance with an embodiment of the present invention.

[018] Figure 5 shows a part of the first frame connected to the perforated screen in accordance with an embodiment of the present invention.

[019] Figure 6a shows left hand side of a part of the first frame connected to the perforated screen in accordance with an embodiment of the present invention. [020] Figure 6b shows middle of a part of the first frame connected to the perforated screen in accordance with an embodiment of the present invention.

[021] Figure 6c shows right hand side of a part of the first frame connected to the perforated screen in accordance with an embodiment of the present invention.

[022] Figure 7 shows the perforated screen in accordance with an embodiment of the present invention.

[023] Figure 8 shows the conveyor belt in accordance with an embodiment of the present invention.

[024] Figure 9 is side view of the conveyor belt in accordance with an embodiment of the present invention.

[025] Figure 10 shows the elongated member in accordance with an embodiment of the present invention.

[026] Figure 11 is a front view of the elongated member in accordance with an embodiment of the present invention.

[027] Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.

DETAILED DESCRIPTION OF THE INVENTION

[028] The present invention relates to a system for water treatment. The system is directed for removing floating debris in an open water channel. The open channel refers to any open channel in which there is flow of water and includes a canal, a stream and an open drainage. The floating debris refers to waste materials that are thrown or discarded into the open channel or get into the open channel or that grow or breed in the open channel and that float in the open channel up to a depth of about 30 cms from the water surface. Typical examples are wood, tree leaves, light metals, paper or plastic items, dead animals and birds, left-over food items, dead fish and weeds.

[029] Referring to Figures 1 and 2, there is shown a schematic representation of the system 100 in accordance with an embodiment of the present invention. The system 100 has a perforated screen 10 and a conveyor belt 30 placed in an open channel 80. The channel 80 is defined by a pair of opposite, mutually parallel channel walls 102, 104 and a bottom. Thus water flows between the channel walls 102, 104.

[030] The perforated screen 10 has a front side 110 and a rear side 120 (as shown in Figure 4) and placed between the channel walls 102, 104. The screen 10 extends from the surface of water towards the bottom of the channel to impede flow of water in the channel 80 thereby accumulating floating debris adjacent to front side 110 of the screen 10 and allowing the water to pass through holes 28 (as shown in Figure 3) provided on the screen 10.

[031] Referring to Figure 3, there is shown a front view of the perforated screen 10 in accordance with an embodiment of the present invention. There is a plurality of holes 28 provided on the screen 10 which allow water to pass through but obstruct the debris floating in the water. Accordingly, diameter of the holes 10 will depend upon the size of floating debris. In an embodiment of the invention, the diameter of the holes is in a range of 10 mm to 20 mm. Further, height Ή’ of the screen 10 will depend on depth below the water surface at which debris floats and height of debris above the water level. In an embodiment of the invention, the height Ή’ of the screen is 50 cm. It may be noted that screen 10 may be one screen or may be made of several screens lOa, lOb, lOc of varied widths. Typically, width‘W’ and thickness of screen are selected based on open area of plate, drag force on screen, strength requirement, market availability, deflection of screen under horizontal force and material of screen. In an embodiment of the invention, screen 10 is an acrylic plate or any other light weight, less cost plate with sufficient strength and durability having plurality of holes. In another embodiment of the invention, width‘W’ of the screen 10 is approximately as that of the channel 80 defined by the opposite channel walls 102, 104. In a further embodiment of the invention, the screen 10 is placed in the channel 80 at approximately 45 degrees to the flow direction of water.

[032] As shown in Figures 1 and 2, the system 100 includes a first frame 60. Referring to Figure 4, there is shown a barrier unit 200 comprising the screen 10 and the first frame 60. The frame 60 includes a first pair of vertical, spaced apart, mutually parallel rigid members 12, 12’, a second pair of vertical, spaced apart, mutually parallel rigid members 16, 16’, a horizontal rigid member 22, plurality of rollers 90, a lateral rigid member 24 and a float 20. Lower ends‘A’ of the first pair of the vertical rigid members 12, 12’ are rigidly fixed with and mounted on one of the channel wall 102 (as shown in Figure 2). Further, lower ends‘A’ and upper ends‘A” of first pair of the rigid material 12, 12’ are joined by a lower tie 14 and an upper tie 14’ respectively. Similarly, lower ends‘B’ of the second pair of the vertical rigid members 16, 16’ are rigidly fixed with and mounted on another channel wall 104 (as shown in Figure 2). Lower ends‘B’ and upper ends Έ” of second pair of the rigid material 16, 16’ are joined by a lower tie 18 and an upper tie 18’ respectively. Further the horizontal rigid member 22 is provided between the first pair 12, 12’ and the second pair 16, 16’ of the vertical rigid members. The horizontal member 22 has a first side end‘S’ and a second side end‘S” extending between the first 12, 12’ and the second pair 16, 16’ of the vertical rigid members. In an embodiment of the invention, as shown in Figure 4 and 6 the horizontal member is made of multiple members - left hand side horizontal member 22a, middle horizontal member 22b and right hand side horizontal member 22c. The individual horizontal members 22a, 22b, 22c are joined together to extend between the vertical members. The roller 90 is mounted on each of the side ends S, S’ of the horizontal rigid member 22 and engageable between the respective pair of vertical rigid members 12, 12’ and 16, 16’. In this regard, a frame F with multiple rollers 90 may be provided wherein the frame F is configured to receive the side ends S, S’ of the horizontal rigid member 22. The rollers 90 are configured to move between the vertical rigid members 12, 12’ and 16, 16’ thereby moving the horizontal rigid member 22 in a vertical direction. The first frame 60 has at least one lateral rigid member 24 extending from the horizontal rigid member 22. The lateral rigid members 24 are connected preferably at 90 degrees with the horizontal rigid member 22 configured to receive the float 20. The float can be fixedly mounted on the lateral rigid members 24. In an embodiment of the invention, the float 20 is made of light PVC pipes sealed at ends to make air tight. The float 20 tends to move back and forth in a substantially vertical direction in response to water flow rate causing the horizontal rigid member 22 to move in vertical direction.

[033] In an embodiment of the invention, the lateral rigid members 22 are connected to rear side 120 of the perforated screen 10. A shown in Figure 5, an angular member 32 is used to join the lateral rigid member 22 with the rear side 120 of the screen 10. When the floats 20 mounted on horizontal rigid member 22 move back and forth in a substantially vertical direction in response to water flow rate, they cause the horizontal rigid member 22 and thus the perforated screen 10 to move in vertical direction. In this regard, the rollers 90 roll between the vertical rigid members 12, 12’ and 16, 16’ to provide vertical movement to the horizontal rigid member 22.

[034] In another embodiment of the invention, as shown in Figure 7, a rigid member 36 having length approximately equal to the height Ή’ of the screen 10 is mounted lengthwise on either side of the screen 10. In this regard, it may be noted that such embodiment may be used for drains having width less than two meters. The rollers 90 are mounted on the rigid member 36 and placed between each of the pair of vertical rigid members 12, 12’ and 16, 16’ (as shown in Figure 4). Float 20 is mounted on the rear side 120 of the screen 10. Accordingly, when the float 20 moves in a vertical direction, the rollers 90 rolls inside the vertical rigid members 12, 12’ and 16, causing the screen 10 to follow the movement of the float 20.

[035] In yet another embodiment of the invention, as shown in Figure 6C, an angular member 34 is provided between the lateral rigid member 24 and the rear side 120 of the screen 10. Such angular member 34 not only provides additional strength to the first frame 60 but also provides support to the floats 20 mounted on the lateral rigid members 24. [036] As shown in Figures 8 and 9, the conveyor belt 30 has an upper end C’ and a lower end C. The conveyor belt 30 is inclined between the upper end C’ and the lower end C wherein the lower end C is positioned adjacent to the front side 110 of the perforated screenlO. As shown in Figures 1 and 2, the system includes a second frame 70 to provide support to the conveyor belt 30 in horizontal direction. In this regard, the second frame 70 also has means to move the conveyor belt 30. The second frame 70 has a pair of vertical rigid members 72, 74 each of the vertical rigid members mounted on opposite channel walls 102, 104 and a horizontal rigid member 76 having a first end and a second end, the horizontal rigid member extending between the pair of vertical rigid members 72, 74. The upper end C of the conveyor belt is connected to the horizontal rigid member of the second frame. Bearing means 94, 94’ are connected at end of both sides of the horizontal rigid member 76 which permit rolling of the horizontal rigid member 76 on the vertical rigid members 72, 74.

[037] In an embodiment of the invention, each of the vertical rigid member 72, 74 is provided with an additional vertical rigid member 72’, 74’ and mounted on the respective channel walls forming pairs 72, 72’ and 74, 74’ of vertical rigid wall on each of the channel walls 102, 104. As shown in Figure 2, a horizontal member 78, 78’ is provided between each pair 72, 72’ and 74, 74’ of the vertical rigid member thereby strengthening the second frame 70. In this regard, bearing means 94, 94’ are connected to a portion of the horizontal members 78, 78’ wherein the bearing means 94, 94’ receive parts of the horizontal rigid member 76 permitting rolling of the horizontal rigid member 76.

[038] In another embodiment of the invention, a plurality of vessels 40 are mounted on the conveyor belt 30 at predetermined location. The vessels 40 have holes through which water drains out. The diameter of the holes is in a range of 10 mm to 20 mm. Shape and configuration of vessels 40 are chosen such that when the conveyor belt 30 moves from lower end C towards upper end C’, the vessel 40 close to the surface of water collects the accumulated floating debris and drains out the water. [039] In another embodiment of the invention, the conveyor belt 30 is supported on an inclined support having an upper end and a lower end, the upper end fixed to the horizontal rigid member 76 of the second frame 70.

[040] In a further embodiment of the invention, the system 100 includes means for driving the conveyor belt 30 for moving the conveyor belt 30 from the lower end C to the upper end C’ whereby the vessel 40 towards the lower end C collects the accumulated floating debris and moves towards the upper end C’, the vessel 40 while transiting from the upper end C’ towards the lower end C dumps the floating debris in a debris collector 50 (as shown in Figure 1). In this regard the lower end C of the conveyor belt 30 is always placed in adjacent to the front side 110 of the screen 10. The debris collector 50 can be a tray placed adjacent to the conveyor belt to collect debris dumped from the vessels 40. Thereafter, the debris collected in the tray 50 may be removed in a batch.

[041] Means for driving the conveyor belt includes motor and an axle arrangement connected to the bearing means. In another embodiment of the invention, a chain pulley block arrangement is provided between the motor and the conveyor belt. Such arrangement ensures low power consumption thereby eliminating need of heavy powerful motors. Accordingly, system 100 of the present invention can be used round the clock thereby constantly removing the debris from water channel. Moreover, since the system 100 is always placed in an open environment, a solar power unit may be provided to power the motor wherein the solar power unit may be placed on the second frame making the system 100 self-sufficient in all aspects.

[042] Further, as shown in Figures 10 and 11, the lower end C of the conveyor belt 30 or lower end of the inclined support may be connected to an elongated member 46 for providing support and stability to the conveyor belt 30. In this regard, the first frame 60 may be configured to provide an elongated member 46 between the first frame 60 and the lower end C of the conveyor belt. Alternatively, a separate frame similar to that of the first frame 60 may be provided. Accordingly, a float 38 is mounted on the horizontal rigid member 22 and placed between a pair of floats 42, 42’ mounted on the horizontal rigid member 22. The float 38 balances the dead load of conveyor belt 30 and floats 42, 42’ take care of the live load of debris on the conveyor belt 30. Further the elongated member 46 extends from the first frame 60 and connected to the lower end C of the conveyor belt 30 or to the lower end of the inclined support. In an embodiment of the invention, the elongated member 46 is connected between a vertical member 44 extending from the second frame 60 and the lower end C of the conveyor belt or of the lower end of the inclined support. In this regard, the elongated member 46 and the vertical member 44 together forms an ‘L’ shaped rod. Accordingly, the elongated member 46 moves in a vertical direction in response to the movement of the float due to flow of water in the channel. Such vertical movement of the elongated member is transmitted to the conveyor belt 30 which moves in vertical direction due to magnitude of flow of water in the channel.

[043] In operation, screen 10 placed at an angle of 45 degrees with the flow direction impedes the flow of water inside the channel 80 thereby allowing only the water to pass and obstruct the floating debris in front the screen 10. Thus floating debris is accumulated at the end of the barrier unit 200 in between the lower end C of the conveyor belt 30 and the front side 110 of the screen 10. Vessel 40 towards the lower end C of the conveyor belt 30 collects the accumulated floating debris and moves towards the upper end C’ of the conveyor belt 30. The vessel 40 when transiting from the upper end C’ towards the lower end C of the conveyor belt 30 dumps the floating debris in a debris collector 50. Thereafter, the debris collected in the debris collector 50 may be removed in a batch.

[044] Advantageously, the present invention requires only a single driving means to operate the system thereby saving on power consumption. Moreover, implementation cost of the present system is low and requires low maintenance. Further, the system does not require an operator to operate the system. In this regard, once the driving means is switched on the system operates on its own. Thus, the system of the present invention is economical and is a low powered system. [045] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

Claims

WE CLAIM:

1. A system for removing floating debris in an open water channel having a pair of opposite, mutually parallel channel walls and a bottom, the system comprising:

a perforated screen having a front side and a rear side placed between the channel walls, the perforated screen extends from surface of water towards bottom of the channel to impede the flow of water thereby accumulating floating debris adjacent to front side of the perforated screen;

a float connected on the rear side of the perforated screen for allowing the perforated screen to gradually rise from the bottom of the channel corresponding to water flow rate while otherwise being maintained in proximity to the bottom of the channel;

a conveyor belt having an upper end and a lower end, the conveyor belt inclined between the upper end and the lower end and the lower end positioned adjacent to the front side of the perforated screen;

a plurality of vessels mounted on the conveyor belt at predetermined locations; and

means for driving the conveyor belt for moving the conveyor belt from the lower end to the upper end whereby the vessel towards the lower end collects the accumulated floating debris and moves towards the upper end, the vessel while transiting from the upper end towards the lower end dumps the floating debris in a debris collector.

2. The system as claimed in claim 1, comprising a first frame having:

a first pair of vertical, spaced apart, mutually parallel rigid members mounted on one of the channel wall and a second pair of vertical, spaced apart, mutually parallel rigid members mounted on the other channel wall and opposite to the first pair of the vertical rigid member; a horizontal rigid member having a first side end and a second side end extending between the first and the second pair of the vertical rigid members; a roller mounted on each side ends of the horizontal rigid member and engageable between the respective pair of vertical rigid members, the roller configured to move between the vertical rigid members thereby moving the horizontal rigid member in a vertical direction; at least one lateral, rigid member extending from the horizontal rigid member; and

at least one float fixedly mounted on the lateral rigid member, the float tend to move back and forth in a substantially vertical direction in response to water flow rate causing the horizontal rigid member to move in vertical direction.

3. The system as claimed in claim 1 and 2, wherein the frame comprises plurality of the lateral rigid members, each of the lateral rigid members connected to rear side of the perforated screen; and plurality of floats fixedly mounted on the lateral rigid members, the floats tend to move back and forth in a substantially vertical direction in response to water flow rate causing the horizontal rigid member and thus the perforated screen to move in vertical direction.

4. The system as claimed in claim 1, comprising a second frame having:

a pair of vertical rigid members, each of the vertical rigid members mounted on opposite channel walls; and

a horizontal rigid member having a first end and a second end, the horizontal rigid member extending between the pair of vertical rigid member.

5. The system as claimed in claim 4, wherein the upper end of the conveyor belt is connected to the horizontal rigid member of the second frame.

6. The system as claimed in claim 5, comprising bearing means connected at end of both sides of the horizontal rigid member permitting rolling of the horizontal rigid member on the vertical rigid members.

7. The system as claimed in claim 2, comprising an inclined support having an upper end and a lower end, the upper end fixed to the horizontal rigid member of the second frame.

8. The system as claimed in claim 2, comprising a float mounted on the horizontal rigid member and placed between a pair of floats mounted on the horizontal rigid member and an elongated member extending from the first frame and connected to the lower end of the conveyor belt.

9. The system as claimed in claim 7, comprising a float mounted on the horizontal rigid member and placed between a pair of floats mounted on the horizontal rigid member and an elongated member extending from the first frame and connected to the lower end of the inclined support.

10. The system as claimed in claim 1, comprising a tray placed adjacent to the upper end of the conveyor belt to collect debris dumped from the vessels.

11. The system as claimed in claim 1, wherein the perforated screen is an acrylic plate having plurality of holes.

12. The system as claimed in claim 1, wherein the vessels have plurality of holes through which water drains out.

13. The system as claimed in claim 11 or 12, wherein diameter of the holes is in a range of 10 mm to 20 mm.

14. The system as claimed in claim 1, wherein the screen is placed in the channel at an angle of approximately 45 degrees to the flow direction of water.