Abstract:
The circular clarifier cleaning system includes a mainframe to which all various components are attached for the prevention of growth and accumulation of the algae and debris. The components within the system include gravity-driven, horizontal and vertical sweeping chains. The outer trough wall, V-notch weirs, baffle plate wall, and inner baffle plate wall are all cleaned utilizing a rotating chain system device. Two main drag chains are used to clean the effluent trough and the overflow in the overflow wall after the V-notch weirs. An individual chain is utilized as a “garland” to clean the V-notch weirs at the overflow. The circular clarifier cleaning system is driven by an existing skimmer arm found on all secondary clarifiers.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to wastewater treatment systems, and particularly to a circular clarifier cleaning system that can clean and prevent the development of algae and solids accumulation on the surfaces of a circular clarifier in a wastewater treatment plant. 
         [0003]    2. Description of the Related Art 
         [0004]    Clarifiers are well known in the prior art for separating suspended solids from clarified liquids. Most clarifiers operate by sedimentation of solids, i.e., solids sink and are collected from a bottom portion of the clarification vessel, or by flotation, i.e., solids are caused to float and are removed as a flotation blanket from the surface of the clarification vessel. 
         [0005]    In a typical conventional activated sludge sewage treatment process, a considerable volume of scum and other gross floatables enters with the influent feed into the clarifier basin. This is distinct from biological scum, which arises from biological processes occurring in the basin. In conventional clarifiers, the influent scum and other floatables are often moved out of the influent well to be collected along with biological scum over the entire clarifier surface or at the periphery of the clarifier. The two types of scum typically are commingled and discharged together, and where influent well scum and floatables are collected, they are delivered to the periphery of the clarifier and commingled with biological scum. 
         [0006]    Most prior art clarifiers exhibit shortcomings in that they allow algae, sludge and scum accumulation on the surfaces of the baffles, weirs, launders, and troughs. This build-up leads to operator maintenance. 
         [0007]    Circular clarifiers can exhibit significant process advantages, especially when built on a large scale (e.g., sixty feet in diameter or more). In circular clarifiers, beaches are typically deployed radially to provide a surface for floatable solids collection. Also, in circular clarifiers, the influent feed may be introduced from a central, inner portion of the clarifier, and effluent may be removed from the outer perimeter under relatively quiescent conditions. Nevertheless, the problem of algae buildup remains. 
         [0008]    Thus, a circular clarifier cleaning system solving the aforementioned problems is desired. 
       SUMMARY OF THE INVENTION 
       [0009]    The circular clarifier cleaning system includes a mainframe attached to a skimmer arm of a circular clarifier having an influent feed well and an effluent trough. Various components are attached to the mainframe for the prevention of growth and accumulation of algae and debris from surfaces of the circular clarifier. The components within the system include gravity-driven drag sweeping chains, vertically suspended rotating chains, and a chain disposed in a hanging V-formation, the chains being disposed at various orientations in relation to the clarifier surfaces. In this manner, the trough, inner and outer trough wall, V-notch weirs, baffle plate wall, and inner baffle plate wall are all cleaned as the skimmer arm rotates around the clarifier. Two main drag chain assemblies are used to clean the effluent trough and overflow in an overflow wall after a V-notch weir structure of the circular clarifier. An individual chain is utilized as a “garland” to remove trapped solids on the V-notch weirs at the overflow. The clarifier cleaning system is driven by an existing skimmer arm generally found on secondary clarifiers. The attachment could be as simple as drilling two holes in the existing steel arm and bolting up. 
         [0010]    Municipalities throughout the United States utilize either rectangular, circular, or other types of clarification, depending on the engineering concept. This also applies to Industries that produce waste at their production facilities. The circular clarifier cleaning system applies to circular clarifier installations. The system eliminates the necessity of extensive and frequent manual cleaning of those clarifier components by utilizing sweeping drag chains and non-motorized rotating chains that impinge clarifier wall surfaces to allow the process water to flow unabated while preventing algae growth and material matting in the clarifier components. 
         [0011]    These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a partial environmental, perspective view of a circular clarifier cleaning system according to the present invention. 
           [0013]      FIG. 2  is a partial environmental perspective view of the circular clarifier cleaning system of  FIG. 1 , showing the garland chain engaging the V-notch weir gap. 
           [0014]      FIG. 3  is a partial diagrammatic side view of the circular clarifier cleaning system of  FIG. 1 , showing further details thereof. 
       
    
    
       [0015]    Similar reference characters denote corresponding features consistently throughout the attached drawings. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    As shown in  FIGS. 1 through 3 , the circular clarifier cleaning system  10  attaches to an existing clarifier&#39;s scum skimmer arm  2   a . The circular clarifier cleaning system  10  is designed for new or existing circular clarifiers at municipal or industrial wastewater treatment plants. Such circular clarifiers have a clarifier skimmer arm  2   a  and scum scraper blade  2   b , which extend radially across an influent basin  120  to a location proximate the inside wall of the circular clarifier scum baffle B. The arm  2   a  and blade  2   b  are connected to a motor at the center of the circular clarifier to provide rotation of the arm  2   a  and blade  2   b  around the inside periphery of the clarifier scum baffle B. Thus, the circular clarifier cleaning system  10  is driven by an existing skimmer arm  2   a  generally found on secondary clarifiers. The method of attachment could be as simple as drilling two holes in the existing steel arm  2   a  and bolting up an elongate mainframe member  3   a  of the clarifier cleaning system  10 . When attached in this manner, the circular clarifier cleaning system  10  has a low profile, and is also easily accessible. 
         [0017]    The elongate mainframe member  3   a  of the circular clarifier cleaning system  10  is rigidly attached to, and projects radially from, the scum skimmer arm  2   a  in order to extend the cleaning system&#39;s reach over the clear effluent section of the clarifier to a point proximate the inner circumferential portion of the effluent trough wall  17 . 
         [0018]    A baffle wheel positioning member  3   b  is pivotally secured to the mainframe member  3   a  by a bracket assembly  35 . The baffle wheel positioning member  3   b  is constrained to pivot in a plane parallel to the plane defined by rotational sweeping motion of the scum skimmer arm  2   a  and the rigidly attached mainframe member  3   a . Preferably, all pivoting components of the clarifier cleaning system  10  have self-lubricating bearings at their pivot points. 
         [0019]    A spring  5  is attached to the mainframe member  3   a  and to the baffle wheel positioning member  3   b  to bias the pivot direction of the positioning member  3   b  towards the wall of the baffle B. There is one such combination of spring  5  and baffle wheel positioning member  3   b  arranged to bias a positioning member  3   b  towards the inside wall of baffle B, and an opposing such combination of spring  5  and an identical baffle wheel positioning member  3   b  arranged to bias the identical positioning member  3   b  towards the outside wall of baffle B. A planar extension member  30  is attached to and extends downward from one end of the positioning member  3   b  on the side that is biased towards the wall. An L-shaped baffle wheel support member  37   a  is attached to and extends downward from the planar extension member  30 . A wheel  9  having a vertically aligned spin axis is attached to the short leg of the L-shaped baffle wheel support member  37   a  and, due to the pivot bias of the positioning member  3   b , contacts the wall of the baffle B. A plurality of chains  50  are attached to the bottom face of the wheel  9  and are suspended from the wheel  9  at predetermined radial displacements along the bottom face of the wheel  9 , thus allowing the chains  50  to hang down vertically from the wheel  9 . Preferably, all chains utilized in the cleaning system  10  are stainless steel. 
         [0020]    Rotation of the skimmer arm  2   a  causes the wheel  9  in con t act with the wall of the baffle B to turn, thus imparting rotational beating motion in the vertically hanging chains  50  against the baffle wall, which dislodges any debris, algae, or the like from the wall of the baffle B. It should be understood that the vertically hanging chain wall beating members  50  are exemplary, and do not preclude the use of other wall beating members, such as brushes, that may be attached to the wheel  9 . Each wheel  9  of the circular clarifier cleaning system  10  is capable of controlling cleaning elements, such as chains, brushes, squeegees, or a combination thereof, by maintaining a predetermined cleaning tolerance on rough, misshapen, and/or irregular surfaces often found in the walls of a clarifier. The wheels  9  may also control chains, squeegees, or brushes, independently, depending upon the existing conditions at a particular clarifier installation. 
         [0021]    Similar to the baffle cleaning arrangement, a wheel  9  contacts the inside portion of the weir wall  21  and has vertically hanging rotational beating chains  50 , which contact the inner wall of the spillway to dislodge debris therefrom. The wheel  9  in contact with the weir wall  21  is suspended from, and contact-biased by, an L-shaped weir wheel support bracket  7 , which is attached to a weir wheel positioning member  3   c . The weir wheel positioning member  3   c  is attached to the mainframe  3   a  using attachment brackets  35 . A spring  5  is connected to the mainframe  3   a  and the positioning member  3   c  to form the bias of the wheel assembly  9  towards contact with the weir wall  21 . 
         [0022]    Moreover, a similar arrangement of a wheel  9  and vertically disposed rotational beating chains  50  contacts the inner portion of the outer effluent trough wall  17  to dislodge debris therefrom. For example, as most clearly shown in  FIG. 1 , the wheel  9  in contact with the outer effluent trough wall  17  is suspended from, and contact-biased by, an outer effluent trough wheel support bracket  37   c , which is attached to an outer trough wall wheel positioning member  3   d . The outer trough wall wheel positioning member  3   d  is attached to the mainframe  3   a  using attachment brackets  35 . A spring  5  is connected to the mainframe  3   a  and the positioning member  3   d  to form the bias of wheel assembly  9  towards contact with the outer trough wall  17 . 
         [0023]    An individual chain  16  is utilized as a “garland” to clean the V-notch weirs  22  at the overflow. As shown in  FIG. 2 , opposite ends of the chain  16  are suspended from the mainframe  3   a  so that the chain  16  forms a V-shaped span, the tip region of garland V chain  16  dipping into and cleaning the V-notched weirs  22  as the clarifier scum skimmer arm  2   a  rotates. 
         [0024]    As shown in  FIG. 3 , the circular clarifier cleaning system  10  also includes a horizontal effluent trough drag chain curtain  52  and a horizontal spillway drag chain curtain  100 , which are used to clean the effluent trough  20   a  and the upper horizontal portion  20   b  of the spillway wall  19 , respectively. The effluent trough drag chain curtain  52  is suspended from the mainframe  3   a  by two rods  62  or cables attached at two distinct points along the first row of the drag chain curtain  52  and corresponding attachment points along the mainframe  3   a , the corresponding attachments being secured by eyebolts  60  inserted into the mainframe  3   a . The first row of drag chain curtain  52  is maintained in a rigid horizontal row configuration by a series of welds between each of the chain links and is suspended from the mainframe  3   a  so that columns of links in the drag chain curtain  52  are arranged along a portion of a radial line extending from the center of the clarifier. The drag chain curtain  100  has a similarly configured first row, which is maintained by a series of welds between each of the chain links in the first row, and the curtain&#39;s columns are also arranged along a portion of a radial line extending from the center of the clarifier. A rigid spillway chain attachment member  37   d  is vertically and pivotally attached to the end of the weir wheel positioning member  3   c  distal from the mainframe  3   a . A pair of rods or cables is pivotally attached to the end of the spillway chain attachment member  37   d  distal from the weir wheel positioning member  3   c . The rod/cable pair is then attached to the drag chain curtain  100  at the top horizontal row of its chain links, thereby pivotally securing the drag chain curtain  100  to the spillway chain attachment member  37   d  and allowing the drag chain curtain  100  to slide across the upper horizontal portion  20   b  of the spillway  19  to dislodge debris and algae therefrom as the clarifier scum skimmer arm  2   a  rotates. 
         [0025]    An inner trough wall drag chain  54  is pivotally attached to the end of the top row of the spillway horizontal drag chain curtain  100  closest to the inner trough wall  20   c , thereby allowing the inner trough wall drag chain  54  to slide across the slanted inner trough wall  20   c  to dislodge debris and algae therefrom as the clarifier scum skimmer arm  2   a  rotates. 
         [0026]    The circular clarifier cleaning system  10  may be provided as a custom-fitted kit for a specific circular clarifier. An exemplary embodiment of the kit includes an elongate mainframe member  3   a  having drilled holes and associated hardware adapted for attachment of the mainframe  3   a  as a radial extension to the scum skimmer arm  2   a  of the circular clarifier. A positioning member  3   b  is provided and exemplifies a typical attachment to the elongate mainframe member  3   a . A spring  5  attachable to the mainframe  3   a  and positioning member  3   b  is provided to pivotally bias positioning member  3   b  along a horizontal plane. A wheel  9  having its axis of rotation vertically aligned is provided for attachment to the positioning member  3   b . A plurality of vertically extending chains  50  attachable to the wheel  9  is provided. A plurality of positioning member and wheel assembly combinations attachable to the mainframe  3   a  may be included in the kit to provide the capability of cleaning all of the circular walls of the clarifier. 
         [0027]    Additional kit components may include an effluent trough drag chain curtain  52 , which can be suspended from the mainframe  3   a , and a spillway surface drag chain curtain  100 , which is also suspendable from the mainframe  3   a . A length of chain  16  suspendable form the mainframe  3   a  to form a V shape garland is also provided in the kit. 
         [0028]    It is to be understood that the present invention is not limited to the embodiment described above, but encompasses any and all embodiments within the scope of the following claims.