Abstract:
A green garbage treatment apparatus which comprises a disposer, a flow rate adjustment tank for temporarily storing a mixture of a green kitchen garbage ground by the disposer and a kitchen waste water, a solid-liquid separation device for separating the mixture into a solid component and a liquid component, a composting device for composting the solid component, a precipitation-separation device for allowing fine particles in the liquid component to precipitate, a waste water treatment device for subjecting the liquid component fed from the precipitation-separation device via a dividing device to a biological treatment to thereby obtain a treated water, and an insect removal device for removing deleterious insects such as a fly which are generated, for example, in the waste water treatment device. The apparatus is advantageous, in particular, in that it can remove insects such as a fly which are generated in the waste water treatment device.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a waste treatment apparatus comprising a solid-liquid separating device for separating a mixture composed of a solid substance and a liquid substance, the solid-liquid separating device subjecting the mixture to filtering to discharge organic waste water while decomposing organic solid substances by the action of microorganisms existing in the organic solid substance.  
           [0003]    2. Description of Related Art  
           [0004]    Methods of treating organic waste water using aerobic microorganisms have been actively studied and developed. For example, an activated sludge method is usually used in sewage treatment plants, and a submerged infiltration bed is used along with the activated sludge method in combined waste water purifying tanks.  
           [0005]    In addition, methods in which domestic kitchen garbage or the like is fragmented or liquefied by a disposal unit so that it can be treated as waste water containing garbage have been also developed.  
           [0006]    For example, Japanese Patent Laid-Open Publication No. Hei 9-1117 discloses an apparatus in which waste water containing garbage is introduced into a solid substance treating section which decomposes a solid substance by means of microorganisms and discharges primary treated water, which is then introduced into a waste water treating tank for aeration. In this manner, solid substances are decomposed and removed from the waste water containing garbage from the garbage disposal, and the waste water is purified.  
           [0007]    In the apparatus disclosed in the above publication, waste water is subjected to aeration by an air diffuser in the waste water treating tank, which is a treatment basically similar to the activated sludge method.  
           [0008]    The present inventors, on the other hand, found that more effective purification of waste water can be performed when a waste water treating device (a secondary treating device) comprising a packed layer which is packed with microorganism carriers is provided downstream of the solid substance treating device (a primary treating device). (See Japanese Patent Laid-Open Publication No. Hei 11-19674). The inventors of the present application further produced a waste treatment apparatus capable of effectively treating organic waste such as liquid output from a disposal or kitchen waste water using a preferable aerobic treatment by means of natural diffusion of oxygen and without forced circulation of air using an air pump (Japanese Paten Application No. Hei 11-184137).  
           [0009]    With regard to the apparatuses disclosed in the above-mentioned publications, while a waste water treating device comprising a packed layer which contains microorganism carriers has an advantage that an excellent waste water purifying ability can be provided with a simple structure and at a low cost, because waste water typically contains significant amounts of nutrients and oxygen, such waste water provides an environment in which flies and similar vermin can thrive. Therefore, employment of such technology can create a breeding ground for harmful insects. Such an environment is obviously unhygienic and undesirable.  
           [0010]    One method employed to prevent the breeding of insects is to tightly seal the waste water treating device so as to prevent insects from entering. However, the introduction of larvae or eggs in garbage entering the device cannot be prevented by this method. Furthermore, while methods of killing insects by high temperature steam or the like have also been proposed, such methods create a problem that high temperatures can also kill the microorganisms purifying the waste water and would therefore render purification inoperative.  
         SUMMARY OF THE INVENTION  
         [0011]    The present invention was conceived in view of the aforementioned problems of the related art and aims to provide an apparatus for treating garbage, or a waste treatment apparatus, capable of removing insects or the like from the waste water to be treated.  
           [0012]    In accordance with one aspect of the present invention, a waste treatment apparatus comprises a disposal for mechanically reducing waste discharged from a kitchen; a flow rate controlling tank for temporarily storing a mixture of the waste reduced by said disposal and kitchen waste water; a solid-liquid separating device for separating the mixture supplied from the flow rate controlling tank into a solid component and a liquid component; a composting device for converting the solid component separated by the solid-liquid separating device into a compost; a precipitation-separation tank for precipitating fine particles in the liquid component supplied from the solid-liquid separating device; a split-flow device for distributing the liquid component supplied from the precipitation-separation tank; a waste water treating device for biologically treating the liquid part supplied from the split-flow device to thereby produce treated water; and an insect removal device for ridding said waste water treating device of insect manifestation.  
           [0013]    Said insect removal device may introduce into said sealed waste water treating device air or steam or the like at a temperature at which the insects are killed or the activation level of the insects is decreased, but at which the microorganisms required for biological treatment of waste water will not be adversely affected.  
           [0014]    Said temperature may be between 40° C. and 60° C., preferably between 40° C. and 50° C., and more preferably between 45° C. and 50° C. These temperature ranges are preferable because most targeted insects will not hatch after they have been exposed to an environmental temperature of 40° C. for a certain period (see Japanese Patent Application No. Hei 11-270758), and because the level of activation for the microorganisms required for biological treatment decreases at 60° C.  
           [0015]    Said insect removal device may temporarily cause said sealed waste water treating device to be temporarily filled with liquid so as to suffocate or otherwise exterminate manifesting insects.  
           [0016]    Said insect removal device may include a sprinkler located within said sealed waste water treating device for washing the inner wall of the waste water treating device, so as to wash away insects present on the inner wall off. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    These and other objects of the invention will be explained in the description below, in connection with the accompanying drawings, in which:  
         [0018]    [0018]FIG. 1 is a front perspective view showing the structure of an apparatus comprising an organic waste water treatment device in accordance with one embodiment of the present invention;  
         [0019]    [0019]FIG. 2 is a partial perspective view of a solid-liquid separating device  400 ; and  
         [0020]    FIGS.  3 ( a ),  3 ( b ) and  3 ( c ) are schematic views of three embodiments of an insect removal device  900 , FIG. 3( a ) being a heater type device, FIG. 3( b ) being a suffocation type device, and FIG. 3( c ) being a washing type.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]    A first embodiment of the present invention will be described with reference to the accompanying drawings.  
         [0022]    [0022]FIG. 1 shows the structure of a waste treatment system according to the present embodiment, the system being connected to a kitchen counter.  
         [0023]    Referring to FIG. 1, the waste treatment system comprises a disposal  200  for finely grinding, mulching, or similarly reducing into a fine composition waste discharged from a sink  101  of the kitchen counter  100 ; a flow rate controlling tank  300  into which flows a mixture from the disposal of a solid substance such as ground garbage or the like and a liquid substance such as kitchen waste water or the like; a solid-liquid separating device  400  for separating the mixture into a solid substance and a liquid substance; a precipitation-separation tank  700  for precipitating fine particles in the liquid component; a split-flow device  800  for distributing a supernatant pumped from the precipitation-separation tank  700 ; a waste water treating device  500  for performing a purification treatment of the liquid substance; an insect removal device  900  surrounding said waste water treating device  500  for removing insects such as flies; and a solid substance treating device (composting device)  600  for composting the solid substance.  
         [0024]    The disposal  200 , which includes an electromagnetic valve  202  and a start switch  203 , is disposed under the sink  101  while the solid-liquid separating device  400 , the precipitation tank  700 , the split-flow device  800 , the secondary treating device  500 , the insect removal device  900 , and the solid substance treating device  600  are housed in a body case (not shown) and is located outside the house. The mixture discharged from the disposal  200  is temporarily introduced into the flow rate controlling tank  300  through an introduction pipe  201 .  
         [0025]    When only water, which is harmless to the environment when discharged into sewerage, is to be directly discharged through the discharge pipe  204 , the start switch is turned OFF to inhibit start of the disposal  200 . The electromagnetic valve  202  then causes the disposal  200  and the discharge pipe  204  to communicate each other, so that water from the sink  101  is discharged into sewerage.  
         [0026]    On the other hand, when garbage or waste is to be discharged along with water from the sink  101 , it is not desirable to discharge such water containing waste untreated, and therefore the start switch  203  is turned ON to start the disposal  200 . The electromagnetic valve  202  then causes the disposal  200  and the introduction pipe  201  to communicate with each other, so that composting and purification, as will be described later, is performed.  
         [0027]    The flow rate controlling tank  300  comprises a storage tank  301  for storing the mixture introduced through the introduction pipe  201 , a solid substance transporting air lift pump  302  for transporting the mixture mainly composed of solid substances existing at the base portion of the storage tank  301  to the solid-liquid separating device  400  through the pipe  303 , and a water level sensor  306  for detecting the water level of the mixture stored in the storage tank  301 .  
         [0028]    The solid-liquid separating device  400  has the structure disclosed in Japanese Patent Laid-Open Publication No. 2000-15010. More specifically, as shown in FIG. 2, the solid-liquid separating device  400  comprises a first slit portion  410 A having a large number of drain slots  411  formed therein, a transport portion  420 A which rotates for transporting the mixture having been subjected to solid-liquid separation, a second slit portion  430 A which is inserted between drain slots  411  and swings between the drain slots for accelerating solid-liquid separation of the introduced mixture, and a position detection portion  440  for detecting the position of the transport portion  420 A. The first slit portion  410 A, the transport portion  420 A, and the second slit portion  430 A are integrally molded from resin, plastic, or the like.  
         [0029]    The first slit portion  410 A has semicircular drain teeth  412  for screening and draining the mixture introduced through the introduction pipe  201 , and an introduction plate  413  for guiding the mixture having been subjected to draining (namely, solid substances in this case) to the solid substance treating device  600 . Each of the drain slots  411  is formed between drain teeth  412 .  
         [0030]    The transport portion  420 A is fixed to a rotation shaft  423  coupled to a motor (not shown), and is composed of a transport plate  421  for transporting solid substances and ribs  422  provided on the rear surface of the transport plate  421 . The ribs  422  are provided so as to provide the transport plate  421 , which is formed of a thin plastic material, with sufficient strength to resist deformation.  
         [0031]    The introduced mixture is subjected to solid-liquid separation at the first slit portion  410 A, such that the solid substances are separated from liquid and are accumulated on the first slit portion  410 A. The second slit portion  430 A connected to the lower end portion of the transport portion  420 A is rotated back and forth a plurality of times, to thereby accelerate the solid-liquid separation by the first slit portion  410 A. Then, with one clockwise rotation of the transport portion  420 A, the solid substances are transported onto the transport plate  421  which then drops them onto the introduction plate  413 .  
         [0032]    Referring back to FIG. 1, numeral  700  denotes the precipitation-separation tank  700  which precipitates fine particulate from the liquid component supplied from the solid-liquid separating device  400 , and numeral  500  denotes the secondary treating device functioning as an organic waste water treating device for treating organic waste water (primary treated water) which is discharged from the solid-liquid separating device  400 . Further, numeral  800  denotes the split-flow device which distributes and introduces the supernatant supplied from the precipitation-separation tank  700  into the secondary treating device  500 .  
         [0033]    In this example, the split-flow device  800 , in order to distribute the waste water into three portions of the waste water treating device  500 , has three cutout portions (triangular weirs)  801   c  of the same height for evenly distributing the waste water into three flows. Sludge accumulated on the portion before these cutouts  801   c  are returned to the flow rate controlling device  300 .  
         [0034]    The waste water treating device  500  comprises two perforated cylindrical mesh basket containers  510   a ,  510   b  having a diameter of 15 cm and a total height of the containers  510   a  and  510   b  is 15 cm. These mesh basket containers are vertically arranged to be in contact with one another.  
         [0035]    The purpose for vertically arranging the cylindrical mesh basket containers  510   a ,  510   b  in upper and lower levels in contact with each other is as follows. When the garbage treatment apparatus is used for an extensive time, the container  510   a  at the upper level will eventually become clogged with solid substances, thereby preventing water from flowing through the container. To deal with this problem, maintenance of the containers is necessary. In this maintenance, the container  510   a  at the upper level is replaced by the container  510   b  at the lower level, and a new microorganism carrier is supplied at the lower level. The vertical two-level arrangement according to the present embodiment facilitates such maintenance.  
         [0036]    It should be noted that any number (2 or more) of levels of the cylindrical containers  510   a ,  510   b  may be provided for similarly achieving the effects of the present invention.  
         [0037]    The ratio of the average grain size of the microorganism carriers within the cylindrical containers  510   a  and  510   b  is set to 1:1.5˜2.5, because when the ratio is greater than 1:1.5˜2.5 there is a possibility that a microorganisms carrier having a smaller average grain size would enter a microorganism carrier having a larger average grain size.  
         [0038]    All the containers are packed with wood chips (microorganism carriers) composed of shavings of Japanese cedar, so that the waste water treating device  500  subjects organic components within the introduced organic waste water to an oxidation decomposing treatment by means of aerobic microorganisms living in the carriers.  
         [0039]    In the example described, the mesh size (a gap) of the cylindrical mesh basket containers  510   a ,  510   b  is 3˜7 mm, preferably 5 mm, and the size of wood chip is 2˜10 mm.  
         [0040]    In another configuration, in the cylindrical mesh basket containers  510   a  and  510   b , the bottom 5 cm are packed with wood chips of 5˜10 mm size and next 10 cm are packed with 2˜4 mm wood chips.  
         [0041]    In still another configuration, central cylindrical areas (diameter: 5 cm) in the cylindrical mesh basket containers  510   a  and  510   b  are packed with wood chips of 2˜4 mm size, and peripheral areas of the cylindrical mesh basket containers  510   a  and  510   b  are packed with 5˜10 mm wood chips.  
         [0042]    Other types of containers other than mesh basket containers may be used as the cylindrical containers  510   a ,  510   b , as long as they include holes through which air can pass. Unglazed containers may be used, for example.  
         [0043]    Weirs (cutout portions) are formed in the split-flow device  800 . The action of these weirs (cutout portions) allows the primary treated water to be evenly distributed into a plurality of waste water treating devices  500  located below.  
         [0044]    The weir (a cutout portion) of the split-flow device  800  is formed by cutting out a triangular piece having each side of 5 cm. It is preferable to appropriately vary the side length of the triangular piece in proportion to an amount of liquid to be supplied from the precipitation-separation tank  700 . If the weirs are small even when a large amount of the liquid component is supplied, the liquid would overflow from the split-flow device  800  or the weirs would be clogged with fine particles contained in the liquid supplied from the precipitation-separation tank  700 .  
         [0045]    Further, the split-flow device  800  preferably has an inclined bottom so as to allow cleaning when sludge is accumulated thereon, and a pump is provided for pumping the accumulated sludge. The waste water after cleaning is returned back to the flow rate controlling tank  300  or the precipitation-separation tank  700 .  
         [0046]    A discharge pipe  560  is connected to the bottom of the containers  500  for discharging treated water.  
         [0047]    In the waste water treating device  500  having the structure as described above, the primary treated water in the solid-liquid separation device  400  is diffused on the center part of the surface of the cylindrical mesh basket containers  510   a , flows downward in contact with the microorganisms which decompose the organic components in the primary treated water, and is finally discharged through the discharge pipe  560  out of the garbage treating apparatus.  
         [0048]    Referring now to FIG. 3( a ), the insect removal device comprises a housing  910  for storing the waster water treating device  500 , a heater  920  installed in the housing  910  for heating the waste water treating device  500 , temperature sensors  930  provided for respective microorganism carriers in the waste water treating device  900 , and a fan  940  for making the temperature inside the waste water treating device  500  uniform. The heater  920 , which is an electrothremal heater, generates heat when a current flows therethrough, to heat gas within the housing  910  and thereby heat the waste water treating device  500 . The waste water treating device  500  also contains steam as a result of evaporation of the waste water (and a treated water) contained threrein. Heat generation by the heater  920  is controlled in accordance with the temperature detected by the temperature sensor  930 , so that the interior of the housing  910  is heated within a determined temperature range. It is also possible to heat the interior of the housing  910  by introducing heated air or heated stream into the housing  910 .  
         [0049]    In another embodiment, as shown in FIG. 3( b ), the insect removal device  900  comprises a housing  950  for storing the waste water treating device  500 , an inlet port  960  for introducing water in the housing  950 , and a water level sensor  970  for detecting the water level in the housing  950 . In this configuration, by introducing water into the housing  950 , it is possible to submerge the waste water treating device  500 .  
         [0050]    In still another embodiment, as shown in FIG. 3( c ), the insect removal device comprises a housing  980  for storing the waste water treating device  500  and sprinklers for evenly diffusing water onto the inner wall of the housing  980 .  
         [0051]    Referring back to FIG. 1, the solid substance treating device  600  comprises a treating tank  610  for storing the solid substances introduced after solid-liquid separation, a stirrer  620  for stirring the solid substances, and a heater or the like (not shown).  
         [0052]    The treating tank  610  contains carriers composed of wood chips or shavings or the like and activated carbon for cultivating microorganisms. The microorganisms decompose the solid substances into carbon dioxide and water so as to produce compost.  
         [0053]    The solid substances and the carriers are mixed by the stirrer  620  while air is introduced inside the treating tank  610  which is maintained at a predetermined temperature (30° C.˜40° C. in the present embodiment) by the heater, to thereby accelerate activation of the microorganisms or the like.  
         [0054]    The operation of the waste treatment apparatus having the above structure will next be described.  
         [0055]    When waste is to be treated, the start switch  203  is turned ON to start the disposal  200 . As a result, the electromagnetic valve  202  is operated so that garbage discharged from the sink  101  is ground in the disposal  200  and is then introduced into the storage tank  301  through the introduction pipe  201 .  
         [0056]    By configuring the introduction pipe  201  such that it is inclined by an appropriate amount, it is possible for the ground garbage to be transported into the storage tank  301  without employing a separate drive force or the like.  
         [0057]    When waste treatment is not required (for example, when fresh water is discharged), the start switch  200  is left OFF. In this state, the electromagnetic valve  202  would not operate, so that waste water or the like flows directly into the discharge pipe  204 .  
         [0058]    The majority of the solid substances contained in the mixture introduced into the storage tank  301  precipitate and collect at the bottom of the storage tank  301 . The mixture thus collected at the bottom of the storage tank  301  is transported through the pipe  303  to the solid-liquid separation device  400  by means of the solid substance transporting air lift pump  302 .  
         [0059]    At this point, the state of the transport portion  420 A of the solid-liquid separating device  400  is as shown in FIG. 2. Specifically, the standby switch  442  is operated by the magnet  441  so that the transport plate  421  awaits introduction of the mixture at a standby position.  
         [0060]    Accordingly, the mixture transported from the flow rate controlling tank  300  contacts the transport plate  421  and loses energy and speed, such that it accumulates on the first slit portion  410 A.  
         [0061]    The transport portion  420 A and the second slit portion  430 A swing back and forth by means a motor (not shown) to stir the agglomeration of the mixture, and thereby achieve highly efficient solid-liquid separation.  
         [0062]    Because the optimum number of swing depends on the type of solid substance, the number of swinging movements for each introduction of the mixture can preferably be set to a rate optimized for the introduced substance. However, from the standpoint of solid-liquid separation efficiency, a range of 5˜40 times is preferable.  
         [0063]    After a predetermined number of swinging movements, the transport portion  420 A rotates until the solid substance discharge position switch  444  operates, so that the solid substances separated from the liquid component is placed into the solid substance treating device  600 .  
         [0064]    The treating tank  610  of the solid substance treating device  600  contains the carriers composed of wood chips or shavings and activated carbon for cultivating microorganisms. The solid substances having been subjected to solid-liquid separation and introduced into the treating tank are decomposed for composting, and then bagged or the like for discharge.  
         [0065]    The lower the water content in the solid substances separated from the liquid component in the solid-liquid separation device  400 , the shorter the time required for composting the solid substances. If it is desired that treatment be completed within a fixed amount of time, the capacity of the treating tank  610  can be designed sufficiently large for treating the solid substances having a high water content.  
         [0066]    According to the present embodiment, however, the solid-liquid separation efficiency of the solid-liquid separating device  400  is improved as described above, so that the treating tank  610  can be downsized and the cost for the whole apparatus can be reduced.  
         [0067]    On the other hand, the liquid component (organic waste water) having been subjected to solid-liquid separation in the solid-liquid separation device  400  is temporarily stored in the precipitation separation tank  700 . The supernatant in the precipitation separation tank  700  is then transported to the split-flow device  800 , which divides the supernatant into evenly split flows by the action of the weirs (cutouts) and supplies the flows to the waste water treating device  500 .  
         [0068]    According to the present invention, the waste water treating device  500  not only subjects the organic components contained in the introduced organic waste water to oxidation decomposing treatment by means of aerobic microorganisms living in the device, but also rids the waste water treating device  500  of insect infestation.  
         [0069]    As described above, three methods for removing insects are possible. Specifically, in the first example (see FIG. 3( a )), insects are removed by activating the heater  920  to heat the gas in the housing  900 , thereby heating the waste water treating device  500  at 40° C.˜60° C. To prevent low temperature waste water from flowing into the waste water treating device  500  from the split flow device  800 , it is desirable that, during heating, the air lift pump connecting the precipitation separation tank  700  and the split flow device  800  not be activated. By maintaining the temperature in the waste water treating device  500  at 40° C.˜60° C., it is possible to kill or deactivate insects and their larvae or eggs, while reducing the adverse effects on the microorganisms used for treating the waste water in the waste water treating device  500 .  
         [0070]    It is also preferable to heat the waste water treating device  500  to the above-described temperature range by the introduction of high temperature air or steam into the housing  900  sealing the waste water treating device, as described above.  
         [0071]    In the second example (see FIG. 3( b )), the valve of the discharge pipe  560  is first closed, and water is introduced into the housing  950  through the inlet port  960 . When the water level sensor  970  detects the water level at which the waste water treating device  500  is completely submerged, introduction of water is halted. It is sufficient to perform this type of insect removal extermination approximately once a week for about one hour. In order to submerge the waste water treating device  500 , it is desired that the air lift pump connecting the precipitation separation tank  700  and the split flow device  800  be inactivated so as to prevent the waste water from flowing into the waste water treating device  500  from the split flow device  800 . After extermination has been completed, the valve of the discharge pipe  560  is opened to discharge the water within the housing  950 .  
         [0072]    Finally, in the third example (see FIG. 3( c )), insects such as flies present on the inner wall of the housing  980  are washed away by water diffused by the sprinklers  990 , and are then discharged from the discharge pipe  560 . It is sufficient to perform this insect removal by means of water diffusion approximately once a day for about one minute.  
         [0073]    As is obvious from the above description, with the present invention, it is possible to rid the device of insects such as flies which may breed in the device by killing or removing the insect life by means such as heating, drowning, washing away, or the like. In this manner, hygienic waste water can be provided.  
         [0074]    While the preferred embodiment of the present invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the appended claims.