Abstract:
A waste treatment system comprising an impermeable container adapted to accommodate waste, and presenting at least an opening for introducing waste and a plurality of preferential breaking lines for creating respective openings; air-tight closing element of the opening; percolate introduction element within the impermeable container; collector for the formed biogas; a covering layer arranged so as to close the openings; and an air circulation system comprising in turn, within the permeable container a plurality of intake tubes and a plurality of air intakes.

Description:
FIELD OF INVENTION 
       [0001]    The present invention relates to a waste treatment system. 
       BACKGROUND 
       [0002]    The problem of waste disposal or recycling has been particularly felt for some time. In particular, the biggest problems of organic waste are related to its high environmental impact. 
         [0003]    With regard to this, new European regulations related to waste disposal indicate sanitation and composting as particularly valid solutions. 
         [0004]    Composting is a natural form of organic waste disposal known for a long time, by means of which a product, compost, is made and used in agriculture as soil conditioner, as fertiliser or as cultivation substrate. 
         [0005]    In particular, composting is a bioxidising exothermal process which occurs in controlled conditions and, by means of the action of micro organisms, leads to the production of water, carbon dioxide, heat and compost. 
         [0006]    Another form of organic waste exploitation relates to the production of biogas by anaerobic fermentation. The produced biogas may be either converted into electricity and/or heat in a cogeneration system or be introduced directly into the gas network. 
         [0007]    In order to exploit both the potentials of biogas and those of compost, the organic waste recycling process should envisage two consequential steps: a first step in which the organic waste is subjected to an aerobic treatment for biogas formation, and a second step in which the waste is subjected to aerobic treatment for the preparation of compost. 
         [0008]    As apparent, the passage from the first to the second step may entail a series of problems above all of environmental and logistic nature. Indeed, the transportation of waste from an anaerobic reactor to an aerobic reactor is particularly complex and, obviously, environmentally hazardous. 
       SUMMARY 
       [0009]    It is the object of the present invention to make a system for the treatment of organic waste which allows to simply and cost-effectively implement a complete recycling process performed either in only aerobic or in combined aerobic and anaerobic conditions, without presenting logistic or environmental problems. 
         [0010]    The object of the present invention is a waste treatment system comprising a permeable material container adapted to accommodate the waste, and presenting at least one opening for introducing the waste, air-tight closing element of said opening, percolate introduction element within the permeable material container, a collector for the formed biogas, a covering layer made of adsorbing and transpiring material arranged at an upper portion of said container, and a recirculation system of the air within said container. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The following example is provided by way of non-limiting illustration for better understanding of the invention with the help of the figures in the accompanying drawing, in which: 
           [0012]      FIG. 1  is a side section with schematised parts of a preferred embodiment of the system according to the present invention; 
           [0013]      FIG. 2  is a cross-section of the system shown in  FIG. 1 ; 
           [0014]      FIG. 3  is a side section with schematised parts of a second preferred embodiment of the system according to the present invention; and 
           [0015]      FIG. 4  is a cross-section of the system shown in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0016]    In the figure, it is shown as a whole by the waste treatment system object of the present invention. 
         [0017]    System  1  comprises a tubular container  2  made of polyethylene or other suitable material, presenting on one end  2   a  an opening  3  for introducing waste. The tubular container  2  is therefore made of non-rigid material for facilitating transportation, installation and removal thereof. 
         [0018]    System  1  comprises closing element  5  (known and not described in general) for the opening  3 , and an adsorbing and transpiring layer  6  arranged at the upper position  2   b  for closing the openings  4  formed as described below. 
         [0019]    The adsorbing and transpiring layer  6  is formed by an open cell polyurethane matrix impregnated with activate carbon or other filtering system. The adsorbing and transpiring layer  6  has mainly the purpose of blocking odorous substances and filtering them before they are dispersed in the environment and of attenuating the output of bad odours caused by the decomposition of waste during compositing. The function of the adsorbing and transpiring layer  6  is also to adsorb part of the output humidity to gradually give it to the decomposing material. 
         [0020]    According to an alternative embodiment of the system according to the present invention, layer  6  does not present the features set forth above, and it is an impermeable material layer of the type with which the tubular container  2  is made. 
         [0021]    System  1  comprises a recirculation system  7  of the percolate within the tubular container  2  for favouring the production of biogas during the anaerobic processing step. 
         [0022]    The recirculation system  7  comprises a plurality of percolate collection tubes  8  arranged near a bottom  2   c  of the tubular container  2 , a plurality of percolate introduction tubes  9  arranged near the upper portion  2   b  of the container  2 , and a pump  10 . Obviously, the tubes  8  and  9  are appropriately perforated. 
         [0023]    In this way, the percolate inside the biomass can be aspirated by the tubes  8  by the action of the pump  10  and reintroduced within the biomass itself through tubes  9  to favour the production of biogas. 
         [0024]    System  1  comprises a recirculation system  11  of air adapted to ensure appropriate oxygenation during the aerobic step. 
         [0025]    The recirculation system  11  comprises a plurality of air intakes  12  arranged near a bottom  2   c  of the container  2 , a plurality of air intake tubes  13  arranged between the upper portion  2   b  of the container  2  and the adsorbing and transpiring layer  6  and a fan  14  for recirculating the air. Obviously, tubes  12  and  13  are appropriately perforated. 
         [0026]    During the aerobic treatment step, the intake tubes  13  have a two-fold purpose: the first is to take exhausted air from the waste mass being stabilised and to introduce it into the heap, the second is to ensure a closed-circuit system operation without the emission of gas and vapour outside. 
         [0027]    System  1  comprises a device  15  (schematically shown in  FIG. 1 ) for extracting air from outside the tubular container  2 , which is connected to the air circulation system  11 . Device  15  is provided with a valve (known and not shown), for connecting the external air intake to the recirculation system  11  or not according to the quantity of oxygen detected in the recirculation system  11  itself. 
         [0028]    In particular, an oxygen sensor will check the percentage of oxygen present in the air circulating the recirculation system  11 , and when the latter drops under a predetermined limit the valve for mixing the exhaust air with the external air will be opened and the right oxygen mixture will be created. 
         [0029]    Furthermore, the system  1  comprises a biogas collection device  16  (schematically shown in  FIG. 1 ) connected to the air recirculation system  11  and adapted to collect the biogas formed following the anaerobic treatment step. 
         [0030]    Finally, the system  1  comprises a plurality of thermometers  17  (schematically shown in  FIG. 1 ) arranged within the tubular container  2 , and a hygrometer  18  (schematically shown in  FIG. 1 ) accommodated and operating in the recirculation system  11 . 
         [0031]    The system  1  comprises a control unit known and not shown which may be controlled via the Internet and which is capable of managing the various parts of the system. 
         [0032]    In use, the waste to be processed, after being appropriately prepared by possible shredding and sieving, as well as mixed with appropriate structuring material, if required, is charged with inoculation liquid for boosting the fermentation process, and then introduced in the tubular container  2  by a typical bagging machine normally used for farming applications such as those used for bagging fodder and products intended for feeding animals. 
         [0033]    Once the tubular container  2  is filled, the opening through which the waste was introduced is closed, the percolate recirculation system  7  is operated and the conditions for producing biogas, i.e. for performing the anaerobic process step, are created within the tubular container  2 . 
         [0034]    The anaerobic processing step lasts three to four weeks during which a biogas is produced that will be collected by device  16 . The collected biogas will be subjected to a first pre-treatment step related to dehydration and purification and then will be introduced in the cogeneration plant. 
         [0035]    After the first anaerobic processing step, openings  4  are made at the upper portion  2   b . At this point, the most possible percolate which can be aspirated is aspirated from within the tubular container by tubes  8  and recovered in a tank, and the air recirculation system  11  is put into operation. In these conditions, the anaerobic processing step will last for approximately from two to three weeks. 
         [0036]    During this aerobic process step, according to the treatment conditions, either the complete sanitation and bio-stabilisation of the waste heap or the formation of compost is obtained. 
         [0037]    In  FIGS. 3 and 4 , it is indicated by  100  a further embodiment of the system according to the present invention. System  100  comprises a tubular container  101  made of polyethylene or other suitable material and presenting two ends  101   a  and  101   b  closed by respective plates  102  and  103  made of metallic material. As previously specified for system  1 , the tubular container  101  is also made of non-rigid material which facilitates transportation, installation and removal thereof. 
         [0038]    System  100  comprises an adsorbing and transpiring layer  106  arranged at an upper portion  104  of the tubular container  101  to close openings  105  formed as described below. Layer  106  has the same features already shown for layer  6  and is wound on a specific winder/roller  107  fastened to the plate  102 . 
         [0039]    System  100  comprises an air recirculation system  109  comprising a plurality of air intake tubes  110  arranged within the tubular container  101  near the upper portion  104  and fastened to the plate  102 , a plurality of air intakes  111  arranged within the tubular container  101  near a bottom portion  112  and also fastened to the plate  102  and a union line  113  fastened to the plate  102  externally to the tubular container  101  and adapted to join tubes  110  with tubes  111 . The union line  113  comprises in sequence following the flow of air and schematically illustrated in  FIG. 3 , a device  114  for collecting air from the outside provided with valve, an oxygen gauge  115 , a dehumidifier  116  and a fan  117 . Optionally, a cooling element may be arranged on union line  113  and downstream of the dehumidifier  116 . As apparent, tubes  111  and  112  present a plurality of holes adapted to allow the passage of air. 
         [0040]    System  100  comprises a percolate recirculation system comprising a plurality of perforated percolate introduction tubes  118  arranged within the tubular container  101  near its upper portion  104  and fastened to the plate  103 , a plurality of collection tubes  119  arranged within the tubular container  101  fastened to the plate  103  and adapted to take by their ends from within a collection tank  120 , and a union line  121  fastened to the plate  103  externally to the tubular container  101  and adapted to join tubes  118  and tubes  119 . The collection tank  120  is arranged in the bottom portion  112  of the tubular container  101  and collects the percolate formed due to the presence of a plurality of draining tubes  126  resting on the bottom portion  112  arranged on an incline. The union line  121  comprises (schematically shown in  FIG. 3 ) a pump  122  and a union  123  adapted to be connected to an external percolate source to be introduced within the tubular container  101 . 
         [0041]    As described above for system  1 , system  100  comprises (schematically shown in  FIG. 3 ) a biogas collection device  124  connected with the air recirculation system  109  and a plurality of thermometers  125 . 
         [0042]    System  100  comprises a control unit (known and not shown) which may be controlled via the Internet and which is capable of reading the values shown by the measuring instruments and of consequently controlling the various parts of the system. 
         [0043]    The waste treatment procedure using system  100  is the same as that shown with reference to system  1 , with the difference that the percolate introduced within the tubular container may also be originated outside the system and that the air recirculation collection tubes are arranged inside instead of outside the container. 
         [0044]    The system of the present invention offers the advantage that the entire process is performed in a single system thus avoiding movements of materials with respective environmental problems. 
         [0045]    Moreover, the system of the present invention offers the advantage of using particularly economical consumable materials without for this loosing in efficiency, and allows to perform the processing processes without logistic constraints, minimising at the same time the leakage of gas and bad odours. 
         [0046]    Another advantage offered by the system is that it may be mobile and therefore moved to various areas of the waste treatment system according to logistics. 
         [0047]    Moreover, the system of the present invention allows to perform treatments also outdoor or sheltered only by a lean-to roof, thus eliminating the enormous costs for purifying air within specific sheds. 
         [0048]    Finally, the system may be used also separately, i.e. either as an anaerobic system for the production of biogas or an aerobic system for stabilisation and compositing.