Abstract:
A separator and composting unit for a sewage treatment system. The separator and composting unit receives sewage at a rotating separator that drains, or partially drains, the sewage of its liquid. The separator transfer the partially drained sewage to a rotating composting drum wherein the partially drained sewage dries out and transforms to compost while on its way to an exit opening of the composting drum from which it falls out.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority of U.S. Provisional Patent Application No. 61/676,517 filed Jul. 27, 2012, which is incorporated herein by reference in its entirety. 
     
    
     FIELD 
       [0002]    The present disclosure relates generally to waste water (domestic sewage) treatment. More particularly, the present disclosure relates to a system and method for the separation of solids from domestic sewage and for the composting of the solids. 
       BACKGROUND 
       [0003]    Water management is becoming increasingly important, especially in water-scarce regions of the world, such as, for example, the Sun Belt in the U.S.A. In such regions, water taxes are usually high and, as such, there is a strong incentive to conserve and recover water. 
         [0004]    Further, the management and treatment of sewage water is also becoming increasingly important due to costs associated thereto, environmental concerns, and stricter disposal criteria. 
         [0005]    In areas were a municipal sewage system is not available, decentralized sewage systems such as, for example, septic tanks can be used. Such septic tanks usually have two compartments, with a first compartment receiving wastewater, and the second compartment outputting treated water to a leach field (also referred to as a drain field or seepage filed), which can span over a large area, for example, from 200 to 300 m 2  for a three-bedroom house. Solids in the wastewater fall to the bottom of the first compartment while scum floats to the surface. A divider between the first and second compartments has an opening that allows scummy water to flow from the first to the second compartment where additional settling of solids in the water can occur. Anaerobic bacterial activity in the first and second compartments turns the solid deposits into sludge. The liquid present in the second compartment proceeds through the output of the septic tank, into the leach field where the impurities present in the water decompose in the soil. 
         [0006]    Decentralized source separation sewage systems other than septic tanks exist and can allow separation of solids from sewage. However, the separation of the solids from the sewage typically requires a separator and composting device that can be bulky and difficult to service. 
         [0007]    Therefore, improvements in separator and composting devices for sewage treatment are desirable. 
       SUMMARY 
       [0008]    In an aspect of the present disclosure, there is provided a separator and composting unit that comprises: a core assembly; a separator for receiving sewage, the separator having draining slots defined therein, the draining slots to enable liquid in the sewage to drain out of the separator to obtain partially drained solids in the separator; and a composting drum, the separator and the composting drum to be rotatably driven about the core assembly, the core assembly defining a passageway between the separator and the composting drum, the separator to displace the partially drained solids toward the passageway upon being rotated, the partially drained solids to enter the passageway upon reaching the passageway, the passageway to transfer the partially drained solid having entered the passageway to the composting drum. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Embodiments of the present disclosure will now be described, by way of example only, with reference to the attached Figures. 
           [0010]      FIG. 1  shows a perspective view of an embodiment of a separator and composting system in accordance with the present disclosure. 
           [0011]      FIG. 2  shows another perspective view of the separator and composting system of  FIG. 1 . 
           [0012]      FIG. 3  shows a perspective view of an embodiment of a separator used in the separator and composting system of  FIG. 1 . 
           [0013]      FIG. 4  shows a transverse cross-sectional view of the separator of  FIG. 3 . 
           [0014]      FIG. 5  shows a perspective view of an embodiment of a core assembly that can be used in the separator and composting system of  FIG. 1 . 
           [0015]      FIG. 6  shows another perspective view of the core assembly of  FIG. 5 . 
           [0016]      FIG. 7  shows a partial perspective view of an embodiment of a draining chamber and composting drum of the separator and composting system of  FIG. 1 . 
           [0017]      FIG. 8  shows a transverse cross-sectional view of the composting drum shown in  FIGS. 1 and 7 . 
           [0018]      FIG. 9  shows another perspective view of the separator of  FIG. 3 . 
           [0019]      FIG. 10  shows an open view of the separator of  FIG. 9 . 
           [0020]      FIG. 11  shows a perspective view of a draining chamber and composting drum of the separator and composting system of  FIG. 1 . 
           [0021]      FIG. 12  shows a perspective view of another embodiment of a separator and composting system of the present disclosure. 
           [0022]      FIG. 13  shows a side view of the separator and composting system of  FIG. 12 . 
           [0023]      FIG. 14  shows a front view of the separator and composting system of  FIG. 12 . 
           [0024]      FIG. 15  shows a perspective view of a separator in accordance with certain embodiments of the present disclosure. 
           [0025]      FIG. 16  shows an open view of the separator of  FIG. 15 . 
           [0026]      FIG. 17  shows another perspective view of the separator of  FIG. 15 . 
           [0027]      FIG. 18  shows an assembly of hoops in accordance with certain embodiments of the present disclosure. 
           [0028]      FIG. 19  shows a close view of gaps and slots defined in the separator of  FIG. 15 . 
           [0029]      FIG. 20  shows an open, cross-sectional view of the separator of  FIG. 15 . 
           [0030]      FIG. 21  shows a perspective view of an embodiment of a core assembly in accordance with certain embodiments of the present disclosure. 
           [0031]      FIG. 22  shows a top view of the core assembly of  FIG. 21 . 
           [0032]      FIG. 23  shows a perspective view of certain element of the separator and composting system of  FIG. 12 . 
           [0033]      FIG. 24  shows another perspective view of the core assembly of  FIG. 21 . 
           [0034]      FIG. 25  shows a side view of the separator and composting system of  FIG. 12 . 
           [0035]      FIG. 26  shows an open, side view of the separator and composting system of  FIG. 12 . 
           [0036]      FIG. 27  shows a perspective view of elements of a composting drum in accordance with certain embodiments of the present disclosure. 
           [0037]      FIG. 28  shows a perspective view of a composting drum in accordance with certain embodiments of the present disclosure. 
           [0038]      FIG. 29  shows another perspective view of the composting drum of  FIG. 28 . 
           [0039]      FIG. 30  shows an open, cross-sectional view of the composting drum of  FIG. 28 . 
           [0040]      FIG. 31  shows a perspective view of a core assembly in accordance with certain embodiments of the present disclosure. 
           [0041]      FIG. 32  shows a top view of the core assembly of  FIG. 31 . 
           [0042]      FIG. 33  shows another perspective view of the core assembly of  FIG. 31 . 
           [0043]      FIG. 34  shows a perspective view of the separator and composting system of  FIG. 12 . 
           [0044]      FIG. 35  shows a front view of a hoop in accordance with certain embodiments of the present disclosure. 
           [0045]      FIG. 36  shows a front view of a hoop in accordance with other embodiments of the present disclosure. 
           [0046]      FIG. 37  shows a front view of the separator and composting system of  FIG. 33 . 
           [0047]      FIG. 38  shows a close-up view of a scraper structure in accordance with certain embodiments of the present disclosure. 
           [0048]      FIG. 39  shows an open view of a separator in accordance with certain embodiments of the present disclosure. 
           [0049]      FIG. 40  shows a close-up view of another scraper structure in accordance with certain embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0050]    Generally, the present disclosure provides a method and system for separating solids from sewage and for composting the separated solids. 
         [0051]      FIG. 1  shows a perspective view of an embodiment of a separator and composting system  50  of the present disclosure. The separator and composting system can also be referred to as a separator-composting system or as a separator-composting unit. As will be discussed elsewhere in the disclosure, the separator and composting system  50  can be made part of a waste water treatment system. 
         [0052]    The separator-composting unit  50  comprises a core assembly  52  about which a separator  54 , a draining chamber  56 , and a composting drum  58  can revolve. The separator  54  has a gear  59  fixedly secured thereto. The separator  54  and its gear  59  can be rotated about the core assembly  52 . The draining chamber  56  has a gear  60  fixedly secured thereto. The composting drum  58  and the draining chamber  56  are fixedly secured to each other. As such, the draining chamber  56 , the composting drum  58 , and the gear  60  can rotate together about the core assembly  52 . Further, the draining chamber  56 , the composting drum  58 , and the gear  60  are not fixedly secured to the separator  54  and the gear  59 , and can therefore be rotated about the core assembly  52  independently from the separator  54  and the gear  59 . The gears  59  and  60  can be driven at different speeds by any suitable gear driving arrangement. As an example, the gear  59 , and the separator  54  can be driven a one revolution per hour, and he gear  60 , and the separator  56 , and the composting drum  58 , can be driven at one revolution per day. Any other suitable rotation speeds are also within the scope of the present disclosure. 
         [0053]    The separator-composting unit  50  can be 45 inches in length and 20 inches in diameter. The diameter can be tapered slightly such that the separator-composting unit  50  has a lesser diameter near the openings  68  than at others regions of the separator-composting unit  50 . Any other suitable dimensions are to be considered within the scope of the present disclosure. 
         [0054]    The core assembly  52  has support members  62  and a sewage inlet  64 . The sewage inlet can have a diameter of four inches or any other suitable diameter. As will be shown further below, the support member  62  can have counterpart support members located on the opposite side of the core assembly  52 . The support members of the present embodiment are to fit into cooperating holding structures located, for example, in a waste water treatment system, to hold the core assembly in a fixed orientation (e.g., horizontally) with respect to the waste water treatment system. The core assembly  52  also has a cleaning access  67  shown plugged by a plug  69 . 
         [0055]    The sewage inlet  64  is to receive waste water (sewage) from a sewage outlet. The separator-composting unit  50  has a series of slots  66  at the periphery of the separator  54  and at the periphery of the draining chamber. The slots (draining slots)  66  extend along the circumference of the separator. The composting drum has openings  68  (e.g., four openings) at the periphery of the composting drum, the openings  68  can be at an end region of the composting drum  58 . There can be any suitable number of slots  66  and openings  66  without departing from the present disclosure. The width of the slots  66  can be 0.04 inch or any other suitable width. The length of the slots  66  can be, for example, of the order of 5 to 20 cm. The diameter of the openings  68  can be 3 inches or any other suitable diameter. 
         [0056]    As will be described in further details below, sewage enters the sewage inlet  64  and propagates to the separator  54 . At the separator, most of the liquid in the sewage exit the separator  54  through the slots  66  of the separator, leaving behind partially drained solids. As the separator  54  rotates, the partially drained solids are forwarded to the draining chamber  56 . Once in the draining chamber  56 , the partially drained solids will further drain itself from liquid through the slots  66  of the draining chamber  56 . As the draining chamber will generally rotate at a lower speed than the separator  54 , the partially drained solids will have a greater draining time in the draining chamber than in the separator  54 . As the draining chamber  56  rotates, the further drained solids are forwarded to the composting drum  58 . As composting drum  58  rotates, the partially drained solids will propagate towards the openings  68  through which it will exit in compost form. A removable compost bin (not shown) can be placed under the openings  68  to collect the compost. 
         [0057]      FIG. 2  shows a different perspective view of the embodiment of  FIG. 1 .  FIG. 2  shows support members  63  (the counterpart support members referred to above) as well as a venting outlet  70 , which can vent the air that comes in the separator-composting unit through the sewage inlet  64 . 
         [0058]      FIG. 3  shows a perspective view of the separator  54 . An arrow  72  indicates the rotation direction of the separator  54 . The separator  54  has a series of blades  74  that extend between opposite walls  76  of the separator. Within the context of the present disclosure, the blades  74  can also be referred to as vanes. When the separator  54  is installed on the core assembly  52 , the blades  74  extend from the inside of the peripheral wall  78  of the separator  54  towards the core assembly  52 . Slots  66  are also shown in  FIG. 3 . 
         [0059]      FIG. 4  shows a transverse cross-sectional view of the separator  54 . The separator has a plurality of compartments  80  separated form each other by blades  74 . As shown in  FIG. 4 , in the present embodiment, the blades  74  are not perpendicular to the inside of the peripheral wall  78 . However, the blades can be at any suitable angle to the peripheral wall without departing from the scope of the present disclosure. Any suitable number of blades  74  can be comprised in the separator  54 . 
         [0060]    Sewage entering the core assembly  52  though the sewage inlet  64  falls into a compartment  80  of the separator  54 . As the separator  54  rotates and some of the liquid in the sewage drains from the separator  54  through the slots  66 , the partially drained solids rise with respect to the bottom of the core assembly. As will be described next, the core assembly defines a slanted passageway in which the partially drained solids fall and, through gravity, propagate to the draining chamber  56 , which can, in some embodiments, be structurally and functionally the same as the separator  54 . 
         [0061]      FIGS. 5 and 6  show perspective views of the core assembly  52 . With reference to  FIG. 5 , when the separator  54  and the core assembly are assembled together, the sewage entering the core assembly  52  through the sewage inlet  64  falls through an opening  81  into a compartment  80  of the separator  54 . Once in the compartment  80 , which is rotating with the separator  54 , the sewage partially drains through the slots  66  of the separator and the partially drained solids rise. The partially drained solids fall into an opening  82  of the core assembly  52  when the chamber in question reaches the opening  82  of the core assembly. The opening  82  is that of a passageway  84  that extends from the top of the core assembly  52  towards the bottom of the core assembly  52 , at an angle such that, when the draining chamber  56  is assembled with the separator  54  and the core assembly  52 , the output of the passageway  84  delivers the partially drained solids to the bottom of the draining chamber  56 . The angle at which the passageway is inclined can be 60° or any other suitable angle that allows the partially drained solids to propagate from the separator  54  to the draining chamber  56 .  FIG. 6  shows a slanted wall  83  of the passageway  84 . At the bottom of the passageway  84  is an opening  85  through which the partially drained solids that entered the passageway at the opening  82  falls into the draining chamber  56 . In the present embodiment, the support member  62  and  63  are opposite ends of longitudinal members  200  shown in  FIG. 5 . 
         [0062]    In the present embodiment, the draining chamber  56  is substantially a copy of the separator  54  (however, this need not be the case). As such, the reference numerals of  FIGS. 3 and 4  are used to describe the draining chamber  56 . When the separator  54 , draining chamber  56 , and the core assembly are assembled together, the partially drained solids entering the draining chamber  56 , through the opening  85  of the core assembly  52 , falls into a compartment  80  of the draining chamber  56  (see  FIGS. 3 and 4 ). Once in the compartment  80 , which is rotating with the draining chamber  56 , the partially drained solids can be further drained through the openings  66  of the draining chamber and the further drained solids rise as the draining chamber  56  rotates. The further drained solids fall into an opening  92  of the core assembly  52  when the chamber in question reaches the opening  92  of the core assembly. The opening  92  is that of a passageway  94  that extends from the top of the core assembly  52  towards the bottom of the core assembly  52 , at an angle such that, when the composting drum  58  is assembled with the draining chamber  56 , the separator  54  and the core assembly  52 , the output of the passageway  94  delivers the further drained solids to the bottom of the composting drum  58 . The angle at which the passageway  94  is inclined can be 60° or any other suitable angle that allows the further drained solids to propagate from the draining chamber  56  to the composting drum  58 .  FIG. 6  shows a slanted wall  93  of the passageway  94 . At the bottom of the passageway  94  is an opening  87  through which the further drained solids that entered the passageway  94  at the opening  92  falls into the composting drum  58 . 
         [0063]      FIG. 7  shows a perspective view of the draining chamber  56  and the composting drum  58  but without their peripheral walls.  FIG. 7  shows the blades  74  of the draining chamber  56  and blades  75  of the composting drum  58 . Within the context of the present disclosure, the blades  75  can also be referred to as vanes. The blades  75  and the peripheral wall of the composting drum  58  define compartments similar to the compartments  80  of the separator  54  and the draining chamber  56  (see  FIGS. 3 and 4 ). The adjacent walls  76  of the draining chamber  56  and the composting drum  58  can be secured together through any suitable means such as bolts and or adhesives, welding, etc. A spacer that interconnects draining chamber  56  and the composting drum  58  can be provided between the adjacent walls  76 .  FIG. 8  shows a transversal cross-sectional view of the composting drum  58 , which has the blades  75  and a peripheral wall  79  that together define compartments  81 . The arrow  73  indicates the direction of rotation of the composting drum  58 . 
         [0064]    Returning to  FIGS. 5 and 6 , when the separator  54 , the draining chamber  56 , the composting drum  58  and the core assembly  52  are assembled together, the further drained solids entering the composting drum  58 , through the opening  87  of the core assembly  52 , falls into a compartment  81  of the composting drum  58  (see  FIG. 8 ). Once in the compartment  81 , which is rotating with the composting drum  58 , the further drained solids rises as the composting drum  58  rotates. The further drained solids falls into an opening  102  of the core assembly  52  when the chamber in question reaches the opening  102  of the core assembly  52 . The opening  102  is that of a channel  104  that extends from the top of the core assembly  52  towards the bottom of the composting drum  58 , at an angle such that the output of the channel  104  delivers the further drained solids to the bottom of the composting drum  58  closer towards the openings  68  of the composting drum  58 . The angle at which the passageway  94  is inclined can be 60° or any other suitable angle that allows the further drained solids to propagate closer to the openings  68 . As more and more drained and composting solids flows out of the opening  87 , the drained and composting solids propagates towards the openings  68 . 
         [0065]      FIG. 9  shows another perspective view of the separator  54 . The separator  54  has a plate  86  that has an outer perimeter  88  than can fit into the inner diameter of the gear  60  of the draining chamber  56  (see  FIG. 1 ) to form a bushing. 
         [0066]      FIG. 10  shows the same perspective view as in  FIG. 7  but without the plate  86  and without one of the walls  76 . In the present embodiment, bolts  90  can be used to connect the gear  59  to the plate  86  (see  FIG. 9 ). Any other suitable fastener can be used without departing from the scope of the present disclosure. 
         [0067]      FIG. 11  shows a perspective view of the draining chamber  56  and the composting drum  58  fixedly secured to each other. The arrow  73  indicates the rotation direction of the draining chamber  56  and the composting drum  58 . 
         [0068]    The separator and composting system of the present disclosure can separate human feces, toilet paper, and kitchen waste from domestic wastewater. After separation of some of liquid and solids of the sewage entering the separator  54 , the partially drained solids (solids and some liquid) enters the draining chamber where a more thorough drainage is completed. This further drained solids enter the composting drum  58  and, after about 20 days, composted solids exit the composting drum  58  through the openings  68 . The composted solids can be collected in any suitable compost bin or receptacle. 
         [0069]    In testing an embodiment of the present disclosure, separation rates of solids from sewage are about 90%. In further results of testing, the quality of the compost (composted solids) is such that there are no repulsive odours, the water content of the compost is reduced to less than 60%, and the fecal coliform levels are lower than the National Science Foundation (NSF) 41 standards. Having the compost confined to a rolling composting drum allows good management practice and if desired, final solar radiation. 
         [0070]    The separation of the solids allows for the capture of about 50% of the phosphorus present in the sewage and produces compost. The present disclosure allows for waste water treatment to be simplified significantly. Further, nutriment reuse becomes a reality and sludge hauling can be reduced, if not eliminated. Compared to septic solutions: odours are reduce to a non repulsive level and Green Gas Emission (GGE) by-products are reduce by 90%. Additionally, separating solids from sewage will stimulate results in urine diversion, which can result in full nutriment reuse (phosphorus and nitrogen). 
         [0071]    The separator-composting unit  50  ( FIG. 1 ) can be made part of any suitable waste water treatment system and can be driven by any suitable means. For example, the separator-composting unit  50 , and other embodiments of the separator-composting unit, can be driven by a turbine such as described in U.S. Pat. No. 8,197,201. 
         [0072]      FIG. 12  shows a perspective view of another embodiment of a separator and composting system  350  of the present disclosure. The separator-composting unit  350  comprises a core assembly  352  about which a separator  354  and a composting drum  358  can revolve (rotate). The separator  354  has a gear  359  fixedly secured thereto. The separator  354  and its gear  359  can be rotated about the core assembly  352 . The composting drum  358  has a gear  360  fixedly secured thereto and can be rotated about the core assembly  352 . Further, the composting drum  358  and the gear  360  are not fixedly secured to the separator  354  and the gear  359 , and can therefore be rotated about the core assembly  352  independently from the separator  354  and the gear  359 . The gears  359  and  360  can be driven at different speeds by any suitable gear driving arrangement. As an example, the gear  359 , and the separator  354  can be driven a one revolution per hour, and the gear  60  and the composting drum  58 , can be driven at one revolution per day. Any other suitable rotation speeds are also within the scope of the present disclosure. 
         [0073]    To service a dwelling occupied by five people the separator-composting unit  350  can be 45 inches in length and 20 inches in diameter. Any other suitable dimensions are to be considered within the scope of the present disclosure. Dwellings with larger occupancy can have a separator-composting unit  350  of larger dimensions. Alternatively, dwellings with larger occupancy can have a separator-composting unit of the same dimensions (45 inches in length and 20 inches in diameter) but with an additional heating element mounted in the separator-composting unit to dry the solids in the composting drum. This is described in greater details below. 
         [0074]    The core assembly  352  is shown with support members  362  and a sewage inlet  364 . The sewage inlet can have a diameter of three inches or any other suitable diameter. As will be shown further below, the support member  362  can extend through the core assembly  352 . The support members of the present embodiment are to fit into cooperating holding structures located, for example, in a waste water treatment system, to hold the core assembly in a fixed orientation (e.g., horizontally) with respect to the waste water treatment system. The sewage inlet  364  is to receive waste water (sewage) from a sewage outlet. 
         [0075]      FIG. 13  shows a side view of the separator-composting unit  350 .  FIG. 14  shows a front view of the separator  354 . 
         [0076]      FIG. 15  shows a perspective view of the separator  354 , which, in this example, is an assembly of several parts. The separator  354  comprises a front wall  400  and a back wall  414 . The gear  359  is fixedly secured to the back wall  414  through any suitable means such as, for example, fasteners, adhesives, friction etc. In other embodiments, the gear  359  and the back wall can be monolithic (i.e., there can be a single piece defining the gear  359  and the back wall  414 ). Located between the front wall  400  and the back wall  414  are two circumference walls  408  and  410 , as well as blades  412 , which are fixedly secured to each other and to the front wall  400  as well as the back wall  414  and the gear  359 . That is, the front wall  400 , the circumference walls  408  and  410 , the blades  412 , the back wall  414 , and the gear  359  are all rotatable together, as a unit, about the core assembly  352  of  FIG. 12 . Returning to the example of  FIG. 15 , the separator  354  also comprises three hoops  402 ,  404 , and  406 . The hoops  402 ,  404 , and  406  are fixedly secured to each other, and aligned with each other, with, for example, fastener assemblies  416 , which can include spacers  418  to maintain the hoops spaced apart at a fixed separation distance. The hoops  402 ,  404 , and  406  do not rotate with the gear  359 ; rather, the hoops remain stationary, with respect to the core to the core assembly  352  of  FIG. 12 . Even though three hoops are shown, embodiments of separators with at least one hoop are also within the scope of the present disclosure. Within the context of the present disclosure, the blades  412  can also be referred to as vanes. In other embodiments the front wall  400 , blades  412 , back wall  414 , and gear  359  can be a single molded part. 
         [0077]      FIG. 16  shows the separator  354  of  FIG. 15  but without the front wall  400  or the hoops  402 ,  404 , and  406 . The present embodiment of the separator  354  has three blades  412  that are wedge-shaped. However, separators with one or more blades, whether they be wedge-shaped or of any other suitable shape (e.g. curve-shaped, flat, inclined, etc.), are also within the scope of the present disclosure. The shape and features of the blades  412  is described in greater detail below. 
         [0078]    Referring again to  FIG. 15 , the front wall  400  is secured to the blades  412  with a bolt and nut arrangement  419 .  FIG. 17 , which is another perspective view of the separator  354 , shows how the gear  359  and the back wall  414  are secured to the blades  412  with the same bolt and nut arrangement. Any other fasteners, adhesive, welding rods, etc. can also be used to secure the front wall  400  to the blades  412  and the blades to the gear  359  and the back wall  414  without departing from the scope of the present disclosure. 
         [0079]    Referring now to  FIG. 16 , the circumference walls  408  and  410  are fixedly secured to the blades  412  with screws  420  or with any other suitable fasteners, adhesive, welding rods, etc. or both. The circumference walls  408  and  410 , and the blades  412 , are dimensioned (sized) such that when the circumference wall  408  and  410  are secured to the blades  412 , they define a gap  422  between the circumference walls  408  and  410 . Further, the blades  412 , the circumference wall  410  and the back wall  414  are dimensioned such that when secured to each other, there is a gap  424  between the back wall  412  and the circumference wall  410 . 
         [0080]    Referring now to  FIG. 17 , the blades  412 , the circumference wall  408  and the front wall  400  are dimensioned such that when secured to each other, through the blades  412 , there is a gap  426  between the front wall  400  and the circumference wall  408 . 
         [0081]      FIG. 18  shows a hoop assembly  428  that comprises the hoops  402 ,  404 , and  406 , as well as the fastener assemblies  416  with spacers  418 . As shown in this example, the hoops can have ends  430  held together by members  432  secured to the hoops by fastener assemblies  416 . The loops can be manufactured with a resilient material that allow for the ends  430  to be spread apart for placement of the hoops on the separator. 
         [0082]    The hoops  402 ,  404  and  406  respectively fit in the gaps  426 ,  422 , and  424 . The thickness of each hoop  402 , 404 , and  406  is less than the width of the respective gaps  426 ,  422 , and  424 . This allows sewage entering the separator  354  to be drained, or partially drained, of its liquid through the slots defined by the hoops  402 ,  404 , and  406 , and their respective gaps  426 ,  422 , and  424 . 
         [0083]      FIG. 19  shows a side, close-up view of the gap  426  defined by the front wall  400  and the circumference wall  408 , the gap  422  defined by the circumference wall  408  and the circumference wall  410 , and the gap  424  defined by the circumference wall  410  and the back wall  414 . The hoop  402  is located in the gap  426 , the hoop  404  is located in the gap  422 , and the hoop  406  is located in the gap  424 . The hoop  402  located in the gap  426  defines a slot  434  and a slot  436 ; the hoop  404  located in the gap  422  defines slots  438  and  440 ; the hoop  406  located in the gap  424  defines slots  442  and  444 . It is through these slots  434 ,  436 ,  438 ,  440 ,  442 , and  444  that liquid from sewage entering the separator  354  can drain. The width of the slots  436 ,  438 ,  440 , and  442  can vary, for example, from 0.02 inch to 0.04 inch to prevent particles having a size greater than the slot with to be drained out of the separator. However, any other suitable widths that allow liquid to drain from the sewage without letting through solid particles greater a pre-determined size are also within the scope of the present disclosure. Even though liquid can drain from the slots  434  and  444 , there presence also serves to reduce friction between the front wall  400  and the hoop  402 , and between the hoop  402  and the back wall  414 . The width of slots  434  and  444  can be narrower than that of the slots  436 ,  438 ,  440 , and  442  and can range, for example, from 0.01 inch to 0.005 inch. The slots  436 ,  438 ,  440 , and  442  can extend along the entire circumference of the separator  354  or only along a portion of the circumference without departing from the scope of the present disclosure. Further, the hoop  402  can have its internal diameter extend lower than the bottom of the front wall  400 , to favor improved draining. This is shown in  FIG. 19  at the slot  403 . Furthermore, the hoop  406  can have its internal diameter extend lower than the bottom of the back wall  414 , to favor improved draining. This is shown in  FIG. 19  at the slot  405 . The width of these slots  403  and  405  can vary, for example, from 0.02 inch to 0.04 inch. 
         [0084]      FIG. 20  shows a transversal, open cross-sectional view of the separator  354 , which includes the blades  412  and the circumference walls  408  and  410 . The view is from the standpoint of a person standing in front of the front wall  400  and looking toward the front wall  400 . These elements, the blades  412  and the circumference walls  408  and  410 , together with the front wall  400  and the back wall  414  define compartments  446 . The arrow  448  indicates the direction of rotation of the separator  354 .  FIG. 21  shows a perspective view of the core assembly  352  to which the gear  360  is secured and about which the separator  354  rotates. 
         [0085]    With reference to  FIGS. 19 ,  20  and  21 , sewage enters the sewage inlet  364  of the core assembly  352  and falls into a compartment  446  of the separator  354 . A portion of the liquid in the sewage exits the compartment  446  of the separator  354  mainly through the slots  403 ,  405 ,  434 ,  436 ,  438  and  440  of the separator, leaving behind partially drained solids. As the separator  354  rotates about the core assembly  352 , the partially drained solids rise along a portion  449  of the circumference of the core assembly  352  to eventually reach an opening  450  of the core assembly  352  and fall into a trough  452 , through the opening  450 . An auger  456  is disposed in the trough  452  and rotates, in the present example, in the same direction (indicated by the arrow  448  in  FIG. 21 ) as the gear  360 , to push the solids in the trough  452  toward the composting drum. As will be understood by the skilled worker, an auger with the opposite handedness would require the direction of rotation to be opposite of that show by arrow  448 .  FIG. 22  shows a top view of the core assembly  452  with the gear  360  secured thereto. In the embodiment of  FIG. 19 , the slots (draining slots)  436 ,  438 ,  440 , and  442  extend along the entire circumference of separator. Further, the hoops  402 ,  404 , and  406  can be referred to as gap inserts, to be inserted in gaps  426 ,  422 , and  424 .  FIG. 23  shows an exemplary mechanism of how the auger  456  is driven. As shown in  FIG. 23 , the auger  456  is mounted on a shaft  457  to which is secured a gear  361 . The internal portion of the gear  360  engages the gear  361  to rotate the gear  361  and the shaft and auger  456  that are secured to the shaft. 
         [0086]    Returning to  FIG. 22 , as the auger  456  rotates, the solids received in the trough  452  through the opening  450  are pushed towards an exit opening in the core assembly  352 .  FIG. 24  shows a bottom perspective view of the core assembly  352  to which the gear  360  is rotatably secured. The exit opening through which the solids are pushed by the auger  456  is shown at reference numeral  458  of  FIG. 24 . As the solids fall out of the exit opening  458 , they fall into the composting drum  358  along the wall  460 , which may, in certain embodiments, be slanted. The core assembly  352  thus defines a passageway between the separator and the composting drum. The passageway, in the present example, connects the separator to the composting drum, through the exit opening  458 . 
         [0087]      FIG. 25  shows a side view of the separator and composting system  350  where the circumference wall  462  of the composting drum  358  is shown;  FIG. 26  shows an open, side view of the separator and composting system  350 . When the solids fall out of the exit opening  458  of the core assembly  352  (see  FIG. 24 ), they land in the composting drum  358  generally at the area  464  shown in  FIG. 26 . The solids present in the composting drum  358  can further drain themselves from liquid trough a slots  466  and  468 , which are described below. 
         [0088]      FIG. 27  shows an open, perspective view of the composting drum  358 , which has a front wall  470  and a back wall  472 , as well as blades  474  that connect the front wall  470  to the back wall  472 . The gear  360  discussed earlier is fixedly secured to the front wall  470  though any suitable type of fasteners, adhesives, or both. In other embodiments, the gear  360  and the front  470  wall can be monolithic. The composting drum  358  is shown with a hoop  476  that remains fixed with respect to the core assembly about which the composting drum  358  rotates.  FIG. 28  shows another perspective view of the composting drum  358 . The hoop  476  is located between the front wall  470  and the circumference wall  462 . The slot  468  is defined by the hoop  476  and the front wall  470 .  FIG. 29  shows yet another perspective view of the composting drum  358 . The slot  466  is defined by the hoop  476  and the circumference wall  462 . Within the context of the present disclosure, the blades  474  can also be referred to as vanes. 
         [0089]    The slots  466  and  468  can have substantially the same width as that of the slots  436 ,  438 , and  440 , described above in relation to  FIG. 19 . 
         [0090]    Referring again to  FIG. 26 , once in the compositing drum  358 , the partially drained solids will further drain itself from liquid through the slots  466  and  468 . As the composting drum  358  will generally rotate at a lower speed than the separator  354 , the partially drained solids will have a greater draining time in the composting drum than in the separator  354 . As the composting drum  358  rotates, the further drained solids are lifted, by the blades  474 , from the area  464  around an extension  478  of the core assembly  352 , towards the top portion  480  of the extension  478 . Once at the top portion  480 , the solids (further drained solids), or a portion of the solids slide down a sloped wall  482  and are forwarded further into the composting drum  58 . As the composting drum  358  continues to rotate, the partially drained solids will propagate towards the back wall  472  of the composting drum, eventually reaching the partition  484  of the composting drum  358 . The partition  484  is also shown at  FIG. 27 . Subsequently, as the composting drum continues to rotate, the solids will fall between the partition  484  and the back wall  472 . The back wall  472 , the partition  484 , the circumference wall  462  (shown in  FIG. 29 ), and the blades  474  define compartments that are eventually reached by the solids in the composting drums.  FIG. 30  shows these compartments at reference numeral  486 . The rotation direction  488  is as observed when facing the back wall  472 . 
         [0091]    Referring now to  FIG. 30  and to  FIG. 31 , as the composting drum  358  rotates about the core assembly  352 , the solids in a compartment  486  rise along a portion  490  of the circumference of the core assembly  352  to eventually reach an opening  492  of the core assembly  352  and fall into a trough  494 , through the opening  492 . An auger  496  is disposed in the trough  494  and rotates, in the present example, in the same direction (indicated by the arrow  448  in  FIG. 21  and by the arrow  488  of  FIG. 30 ) as the gear  360 , to push the solids in the trough  452  through an opening  498  and out of the composting drum  358 .  FIG. 32  shows a top view of the core assembly  452  with the gear  360  secured thereto. The auger  496  is secured to the shaft  457 . 
         [0092]    As shown in  FIGS. 31 and 32 , the support members  362  extend from one end of the core assembly  352  to the opposite of the core assembly  352 . The support members  362  are threaded through apertures of support plates  500  and through spacers  504 , which cover the support members  362  and maintain the support plates  500  at a pre-determined distance from each other. As will be described further below, the support plates  500  serve as a holder for a heating unit. As shown at  FIG. 32 , fixed collars  506  can be secured to the support member  362 . 
         [0093]      FIG. 33  shows the opening  498  through which the solids are pushed by the auger  496 . A compost bin can be disposed beneath the opening  498  to receive the solids form the composting drum  358 . Additionally, the opening  498  can serve as a vent for air that comes in the separator-composting unit through the sewage inlet  364 .  FIG. 33  also shows an optional access tube  508  secured to a sleeve  505 , which can be made of stainless steel or of any other suitable heat conducting material. The access tube  508  and the sleeve  505  are supported in the core assembly  352  by the support plates  500  and by the back wall  511  of the core assembly  352 . A heater element (not shown) can be inserted in the sleeve  505  to heat up and dry the solids in the composting drum  358 . The heater element can be secured in the sleeve  505  in any suitable manner. For example, the heater element and the sleeve  505  could have formed thereon cooperating thread to allow the heater element to be screwed into the sleeve  505 . The opening  510  of the access tube can be left open or can be closed whether or not a heater is present in the holder  508 . 
         [0094]      FIG. 34  shows how the hoops  402 ,  404 ,  406 , and  476  are connected through alignment rods  506 . The alignment rods  506  are fitted through holes  508  defined in each of the hoops  402 ,  404 ,  406 , and  476 . When the separator and composting unit  350  is installed in a waste water treatment system or a sewage treatment system, the support members  362  can be fitted in cooperating holders and, the alignment rods can also be fitted in respective cooperating holders. Additionally, or alternatively, the edges  512  can be abutted against an alignment structure (e.g., a wall) to ensure that hoops remain fixed with respect to the core assembly  352 . 
         [0095]      FIG. 35  shows an embodiment of the hoop  402 . The dashed circle  1000  represents the outer circumference of the circumference wall  408 . The dashed circle  1002  represents the outer diameter of the front wall  400 . The interior perimeter  1003  of the hoop  402  is designed to have a portion  1004  of the interior perimeter  1002  protrude inside the separator  354 . This serves to push solids accumulated in the separator  354 , over the gap  426  (see  FIGS. 17 and 19 ), toward the inside of the separator, thereby preventing blockage of the gap  426 . Further, with reference to  FIG. 19 , the proximity of the portion  1004  of the hoop  402  to the front wall  400  allows the portion  1004  to scrape off any solids, e.g., paper residues, that may accumulate on the front wall  400 , in the separator  354 . The same principle applies to the hoop  406  and the back wall  414 , and to the hoop  476  and the front wall  470 . The hoops  404 ,  406 , and  476  can have the same profile as that shown in  FIG. 35 . 
         [0096]      FIG. 36  shown an embodiment of the hoop  404 . The dashed circle  1000  represents the outer circumference of the circumference wall  408  (or  410 ). The dashed circle  1002  represents the outer diameter of the front wall  400 . As in the example of  FIG. 35 , the interior perimeter  1003  of the hoop  404  is designed to have a portion  1004  protrude inside the separator  354  This serves to push solids accumulated in the separator  354 , over the gap  422  (see  FIGS. 16 and 19 ), toward the inside of the separator, thereby preventing blockage of the gap  422 . As shown in  FIG. 36 , the inside perimeter of the hoop  404  has less overlap with the edges of the circumference wall  408  and  410 , which serves to reduce any friction there may be between the hoop  404  and the circumference walls  408  and  410 . The hoops  402 ,  406 , and  476  can have the same profile as that shown in  FIG. 35 . 
         [0097]    Any hoop that has an inside perimeter that protrudes into the separator is to be considered within the scope of the present disclosure. Further, hoops that do not have an inside perimeter that protrudes inside the separator but nevertheless contribute to define slots for draining liquids from the sewage can also to be considered within the scope of the present disclosure. 
         [0098]    As liquid will drain from the slots defined in the separator  354  and the composting drum  358 , there may be a biofilm forming on the surfaces along which the liquid drains. To mitigate the formation of such biofilms, the separator-composting unit can have scraper structures defined thereon to scrape off biofilms accumulating on these surfaces.  FIG. 37  shows a front view of the separator  354 . The front wall  400  has a number of scraper structures  600  defined thereon. The scraper structures  600  are to scrape off biofilms accumulating on the outside face of hoop  402 , particularly at the bottom region of the hoop  402  where liquid is likely to flow out of the separator  354 .  FIG. 38  shows a close-up view of an embodiment of a scraper structure  600  defined by the front wall  400 . Further, the core assembly  352  can have holder structures  601  to about against the front wall  400  to prevent the front wall  400  from moving off the core assembly  352 . Similar holder structures  601  can be defined on the back wall  511  of the core assembly  352 , as shown at  FIG. 33 . 
         [0099]    Similarly, and as shown at  FIG. 39 , the circumference walls  408  and  410  can have scraper structures  602  formed thereon to scrape off biofilms from the hoops  402 ,  404 , and  406  (not shown in  FIG. 38 ).  FIG. 40  shows a close up view of a scraper structure  602  formed on the circumference wall  408 . As shown at  FIG. 40 , the scraper structure  602  protrudes laterally from the circumference wall  408  in order to engage the adjacent hoop (not shown). Further, the scraper structure  602  has beveled walls (sloped walls)  650  and a low profile, which help reduce any accumulation of matter on the scraper structure and thereby reduces the risk of blockage. 
         [0100]    The back wall  414  can also have scraper structures  600  formed thereon to scrape off biofilms from the hoop  406 . Further, any wall adjacent any hoop, can have scraper structures formed thereon to scrape off biofilms formed on the hoop. For example,  FIG. 28  shows the front wall  470  with scraper structures  600 , and  FIG. 28  shows the circumference wall  462  with scraper structures  600 . Any number of scraper structures is to be considered within the scope of the present disclosure. 
         [0101]    Returning to  FIG. 39 , slot-cleaning devices  800 ,  802 ,  804 , and  806  are shown mounted on an axle  808  that is secured to the hoops  402 ,  404 , and  406  (not shown). The slot-cleaning devices  800 ,  802 ,  804 , and  806  are dimensioned to respectively fit into slots  436 ,  436 ,  440 , and  442  shown at  FIG. 19 . The slot-cleaning devices have a plurality of elongated structures  810  design to push any matter accumulated in the slots towards the inside of the separator  354 . As the separator  354  rotates, the scraping structures  602  formed on the circumference walls  408  and  408  engage the slot-cleaning devices and cause these to turn. The geometry of the slot-cleaning devices ensure that there is always one elongated structure pushing matter accumulated in the slots towards the inside of the separator  354 . 
         [0102]    Returning to  FIG. 37 , a removable cover  700  provides access to the auger  456  (shown at  FIG. 23 ) to allow access to auger, if needed. Further,  FIG. 37  shows an hexagonal portion  702  of the shaft  457 . The hexagonal shaft portion  702  extends outside the separator  456  and rotates with the shaft. The auger  456  can have a corresponding hexagonal cross-section to allow easy mounting and removal of the auger to or from the hexagonal shaft portion  457 . The cover  700 , or any other suitable part of the separator and composting unit can be fitted with a sensor assembly to sense a rotation of the shaft portion  700  and of the shaft. For example, the shaft portion can be fitted with magnets  710  and the cover  700  can be fitted with at magnetic field detector  712  to detect a rotation of the shaft. The magnetic field detector  712  can be operationally connected to a processing means that monitors the rotation of the shaft, which is equivalent to monitoring the rotation of the separator and of the composting drum. Upon detecting the that the shaft no longer rotates, the processing means can trigger a maintenance alert. 
         [0103]    The separator-composting system (or unit) of the present disclosure can be made of any suitable type of material including, for example, plastics, metals, metal alloys, polymers. 
         [0104]    In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments. However, it will be apparent to one skilled in the art that these specific details are not required. In other instances, well-known electrical structures and circuits are shown in block diagram form in order not to obscure the understanding. For example, specific details are not provided as to whether the embodiments described herein are implemented as a software routine, hardware circuit, firmware, or a combination thereof. 
         [0105]    The above-described embodiments are intended to be examples only. Alterations, modifications and variations can be effected to the particular embodiments by those of skill in the art without departing from the scope, which is defined solely by the claims appended hereto.