CLARIFIER FOR REMOVING SOLIDS FROM WASTE WATER

Abstract: The clarifier is positionable in a waste water flow channel (3) and has a body provided with a bow section (11) facing into and extending above the waste water current A, a stern section (12) having an opening (7) below the waste water level (L₁) to allow the waste water to enter the clarifier, a bottom section (15) constructed from parallel baffles (23) separated by openings (24) to allow the solids settled in the clarifier to re-enter the waste water flow channel, and an effluent launder (9) fixedly positioned in the bow section.

Description: CLARIFIER FOR REMOVING SOLIDS FROM WASTE WATER This invention relates to a clarifier for removing solids from waste water, when placed in a flow channel. In conventional waste water treatment processes a portion or all of the waste water is diverted to a settling pond or a flow channel. There the solids contained in the waste water are separated out by settling or chemical treatment. The purified water is then returned to the main waste water stream for final disposition. The e difficulty with the prior art processes is that they result in the addition of contaminating chemical or require extremely large settling ponds or clarifiers relative to the amount of waste water treated or treatment time is too long. It is an object of this invention to provide a waste water clarifier which can more rapidly remove solids from a waste water stream, can be relatively of reduced size and does not require the addition of chemicals to remove the solids. The use of scraping mechanisms is also unnecssary. The present invention provides a clarifier for removing solids from waste water in a waste water flow channel comprising a forward section connected to a rear section by side walls, the forward section and side walls rising above said waste water in use, the rear section having an opening below the waste water level to allow waste water to enter a cavity in the clarifier, a bottom panel below the waste water level and having angularly upwardly extending longitudinal baffle members separated by openings to allow said solids to flow from said cavity back to said channel; and an effluent launder attached to the side walls and positioned in the forward section, said launder comprising a trough arranged to receive waste water from said cavity. Reference is now made to the accompanying drawings, wherein: Figure 1 is a top view of a waste water flow channel with a preferred embodiment of the clarifer positioned therein; Figure 2 is a top view of the preferred clarifier structure of this invention; Figure 3 is a longitudinal cross-sectional view of the clarifier of Figure 2; Figure 4 is a lateral cross-sectional view of the clarifier of Figure 2; Figure 5 is a top view of a waste water flow channel with an alternative embodiment of the clarifier positioned therein; Figure 6 is a cross-sectional view taken along lines IV-IV of Figure 5; and Figure 7 is a cross-sectional view taken along lines III-III of Figure 5. In a waste water treatment process according to this invention as seen in Figures 1 and 2, at least a portion of the waste water is removed from a waste water source 1 by conduit 2 which is provided with conventional screens for removal of large solid materials such as branches, etc. The waste water containing principally suspended solids is then dumped into a waste water channel 3 formed by concrete walls 4 and 5. Within channel 3 the waste water is directed to flow in the directions indicated by the arrows A. As the water flows past the clarifier, denoted generally by the numeral 6, a portion flows back into clarifier- 6 through opening 7 of rear clarifier wall 8, where the waste water is separated into a solid stream and clarified water stream. The clarified water stream is directed into effluent launder 9 where it is either pumped or flows by gravity through return conduit 10 back to water stream 1. Referring now to Figures 2 to 4, a particularly preferred embodiment of clarifier 6 is illustrated comprising, in general, a bow or forward section 11, a stern or rear section 12, side walls 13 and 14 and keel or bottom panel 15 attached to one another in a boat-like shape as shown. In a preferred embodiment, side walls 13 and 14 are positioned a distance away from concrete walls 4 and 5 to avoid any damming problems. Forward section 11 is constructed from an arcuately-shaped bow wall 16 sloped inward from the top, and in one preferred embodiment to bulb-shaped protrusion 17 used to stabilize clarifier 6. Rear section 12 comprises a panel 18 having opening 7 positioned below the channel waste water lever ''L1'' to allow the waste water from channel 3 to flow into clarifier rear chamber 19 where it will eventually rise to level "L2H in middle chamber 20 as shown. The forward section 11 and rear section 12 are attached by side walls 13 and 14 which, in a preferred embodiment, are each constructed from an upper flat section 21 and a lower flat section 22 angled outward along their line of attachment. In this manner, less turbulence is created in the waste water as it flows past clarifier 6. The keel or bottom panel 22 is constructed from parallel rows of hollow tubes 23, preferably rhombus-shaped, which, depending on their orientation, are fixed in position by attaching to side walls 13 and 14 and, in the alternative, the forward and rear sections 11 and 12. Tubes 23 are separated from one another to create slot openings 24 through which solids being settled out of the waste water can re-enter waste water channel 3. Positioned in top of clarifier 6 at forward section 11 is effluent launder 9 which is constructed with multiple troughs 25, 26 and 27, whose sides 28, 29 and 30, respectively, and back side 31 extend upward to a level slightly below level "L2" to allow the clarified water from forward clarifier chamber 32 to enter thr troughs. In another preferred embodiment, side baffles 33, 34, 35 and 36 are positioned along side troughs 25, 26 and 27 as shown with a front baffle 37 positioned in front of troughs 25, 26 and 27 and all of which extend above "L2". In another preferred embodiment, screened side wall parts 38, having adjustable openings 39, are positioned so that any floating solids can be removed from clarifier chambers 19 and 20 by conventional means. In operation, clarifier 6 is placed in channel 3 so that forward section 11 faces into the waste water current. Because clarifier 6 restricts the waste water flow, the velocity of the waste water is increased as it passes clarifier 6. In this regard, it is preferred that clarifier 6 be positioned near channel bottom 53 to increase the waste water velocity past clarifier 6. It is also preferred that clarifier 6 be anchored in position by any conventional means. This increased velocity results in waste water entering clarifier chamber 19 through rear clarified wall opening 7. The waste water entering rear section 12 flows toward forward section 11. Since this flow is at a substantially reduced velocity, solids suspended in the waste water settle toward tubes 23 and are removed through slot openings 24. This results in a clarified waste water strata at the upper portion of clarifier chambers 19 and 20. This clarified strata is allowed to enter troughs 25, 26 and 27, where it is removed by conduit 10 and discharged to the water stream 1. It has been found that by using the clarifier configuration disclosed the turbulence of the waste water flowing past clarifier 6 and turbulence of the waste water in clarifier chambers 19 and 20 have been minimized, resulting in more rapid and efficient removal of solids from the waste water. In an alternative embodiment as shown in Figures 5 to 7, a modified baffling configuration is disclosed. A rear baffle 40 is attached between side walls 13 and 14 and extends downward toward the clarifier bottom 41. It is also preferred that a second rear baffle 42 be positioned between rear baffle 40 and launder 9 to help reduce turbulence in clarifier 6. Second rear baffle 42 preferably extends only partially between side walls 13 and 14 and like rear baffle 40 extends downward toward bottom 41. Clarifier bottom 41 is provided with parallel rows of openings 43 extending the length of clarifier 6. Sloped rectangular panels 44, 45, 46 and 47 are attached to side walls 13 and 14 and bottom 41 to form troughs 48 that direct the settling waste toward openings 43. In order to further reduce turbulence in the clarifier chambers resulting from bubbling of air in the waste water through openings 43, it is preferred that directional tubes or pipe stems 49 extend downward from bottom openings 43 at an angle so that pipe openings 50 face away from the flow of the waste water stream. In a more preferred embodiment, pipe opening face 51 is perpendicular to clarifier bottom 41. In another embodiment, keel braces 52 are positioned on either side of pipe stems 49 not only to support the pipe stems but also to guide the waste water stream around pipe stems 49. In this embodiment, the waste water entering through opening 7 flows toward bow section 11. As in the first embodiment, this flow is at substantially reduced velocity so solids suspended in the waste water settle toward opening 43 and are removed through pipe openings 50. This results in a clarified waste water strata at the upper portion of clarified chamber 32. This clarified strata is allowed to enter effluent launder 9 where it is removed by return conduit 10 and discharged back into the water stream 1. It has been found that by using the clarifier configuration claimed turbulence of the waste water flowing past clarifier 6 and turbulence of the waste water in clarifier chambers 19 and 20 have been minimized resulting in more rapid and efficient removal of solids from the waste water. Present day clarifier and settling ponds are designed to achieve a clarified water discharge stream containing less than 20 ppm of suspended solids. To achieve this discharge rate, clarifier 6 is placed in channel 3 and an equilibrium state is reached. At this point, the forward openings 43 near launder 9 can be plugged or restricted and the clear water removal rate can be increased. This method allows slower water movement in clarifier 6 and, therefore a greater clear water zone. This balancing, by further restricting the openings in those sections on which the sludge blanket has been removed, allows for greater removal from launder 9 and, therefore, increased capacity.

Claims: CLAIIIS 1. A clarifier for removing solids from waste water in a waste water flow channel comprising a forward section (11) connected to a rear section (12) by side walls (13, 14), the forward section and side walls rising above said waste water in use, the rear section having an opening (7) below the waste water level to allow waste water to enter a cavity (32) in the clarifier, a bottom panel (15) below the waste water level (L1) and having angularly upwardly extending longitudinal baffle members (23, 44) separated by openings (24, 43) to allow said solids to flow from said cavity back to said channel; and an effluent launder (9) attached to the side walls and positioned in the forward section, said launder comprising a trough (25, 26, 27) arranged to receive waste water from said cavity (32). 2. A clarifier according to Claim 1 wherein the forward section has an arcuately-shaped forward upright wall (16). 3. A clarifier according to Claim 2 wherein the forward upright wall (16) is sloped inwardly from its top towards its bottom. 4. A clarifier according to Claim 3 wherein the forward upright wall (16) is provided with a bulb-shaped protrusion (17) positioned at the bottom of the wall. 5. A clarifier according to Claim 1 wherein said baffle members (23, 44) extend parallel to the side walls (13, 14). 6. A clarifier according to any preceding claim wherein the baffle members are hollow. 7. A clarifier according to any preceding claim wherein each side wall comprises an upper flat section (21) and a lower flat section (22) angled outward towards a line at which they are sealingly attached. 8. A clarifier according to any preceding claim, wherein longitudinally extending rows of bottom openings (43) are provided and hollow directional tubes (49) connect with the bottom openings (43) and are angularly inclined downwardly from the bottom panel (15) facing towards the rear section (12). 9. A clarifier according to Claim 8 wherein parallel keel members (52) are attached to and extend longitudinally of the bottom panel (15} on opposite sides of each row of openings (43). 10. A clarifier according to Claim 8 or 9 wherein the downwardly protruding ends (51) of the tubes are perpendicular to the bottom panel (15). 11. A clarifier according to Claim 8, 9 or 10 wherein one or more rear baffles (40, 42) is positioned in the rear section and extends laterally between the side walls (13, 14) and downwardly towards the bottom panel (15). 12. A process for clarifying a waste water stre prising: (a) a circuitously flowing said waste water stream in a channel (3) having an elongate clarifier positioned therein with its front section (11) heading into the flow of said waste water stream and positioned to decrease the cross-sectional area of said waste water stream in the channel, (b) diverting a portion of the waste water stream into the clarifier, (c) causing said portion to flow at a rate and distance sufficient to separate said portion into a clarified stream and a solids stream, (d) removing said solids stream from the clarifier, and (e) removing the clarified stream from said clarifier. 13 A process according to Claim 12 wherein the solids stream is removed from the clarifier through ports (24) positioned in the bottom of the clarifier. 14. A process according to Claim 12 or 13 wherein said portion of said waste water stream is diverted through an opening (7) in the rear portion of the clarifier. 15. A process according to Claim 14 wherein said opening is completely located below the level of said waste water in said channel. 16. A process according to Claim 14 or 15 wherein the opening is in the stern of the clarifier.

Inventors: BEARD, HAROLD JAMES
Applicants: BEARD, HAROLD JAMES
Application year: 1982
Main classification: B01D21
IPC codes: B01D21