Method for digesting biodegradable packaging waste and apparatus therefor

Abstract

The present invention relates to a method and an apparatus for digesting biodegradable packaging waste. In particular, the present invention relates to a method and an apparatus for treating biodegradable packaging waste before subjecting the biodegradable packaging waste to biological valorization means. The apparatus includes a tank for receiving the biodegradable packaging waste therein, the tank having a top and a bottom below the top, an air supply module adapted to supply air to the tank, and a microorganism injector adapted to inject mesophilic microorganisms into the tank such that the tank is adapted to receive the biodegradable packaging waste, air, and mesophilic microorganisms therein, and the biodegradable packaging waste is subjected to mesophilic aerobic digestion before being conveyed from the tank to a biological valorization system to subject the biodegradable packaging waste to a biological valorization process.

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for digesting biodegradable packaging waste. In particular, the present invention relates to a method and an apparatus for treating biodegradable packaging waste before subjecting the biodegradable packaging waste to biological valorisation means.

Background Art

[0002] The convenience provided by disposable packaging for the food service sector, such as quick service, casual dining, and fast casual restaurants, has been widespread for many years, and the use of such packaging has increased along with the increase in labor costs and table turnover rate. As a result, the use of disposable packaging for the food service sector is increasing.

[0003] When disposable packaging is disposed of, waste that can be composed of pulp, fiber, plastic, and metal materials is often mixed with post-consumer food waste, i.e., often mixed waste. Mixed waste, i.e., packaging waste and food waste, is generally disposed of by incineration or landfill. Recycling efforts are difficult because the waste needs to be separated into each material type, and are also cumbersome and resource-intensive.

[0004] In contrast to partially biodegradable or non-biodegradable materials, by using fully biodegradable materials for packaging, both packaging waste and food waste can be passed through biological valorisation processes such as enzymatic hydrolysis, fermentation, anaerobic digestion, or industrial composting, avoiding the need to separate mixed waste.

[0005] Wastes derived from biodegradable packaging can be decomposed by the biological valorization process, but often require a long time to do so. Therefore, compared with current industrial practices, it may be cost-inefficient and not practical. For example, some biodegradable packaging may take up to six months to biodegrade in industrial composting sites that typically process food waste within two months. In industrial anaerobic digestion, these biodegradable packaging wastes may take more than 120 days to decompose, as opposed to 20 - 30 days in food waste. This makes it impractical to biodegrade biodegradable packaging together with food waste. Therefore, the possibility of disposing of such mixed waste by incineration or landfilling is higher than biodegrading it by biological valorization means.

[0006] Therefore, it would be good if there were a way to shorten the time it takes to decompose biodegradable packaging waste to match the time it takes to decompose organic waste, so that it is more practical and attractive to biodegrade biodegradable packaging waste without separating it from food waste.

Summary of the Invention

[0007] According to various embodiments, a method of treating biodegradable packaging waste before subjecting the biodegradable packaging waste to a biological valorization process is provided. The method includes subjecting the biodegradable packaging waste to mesophilic aerobic digestion before subjecting the biodegradable packaging waste to a biological valorization process.

[0008] According to various embodiments, the mesophilic aerobic digestion of the biodegradable packaging waste can be maintained at a temperature in the range of about 20°C to about 45°C. According to various embodiments, the mesophilic aerobic digestion of the biodegradable packaging waste can be maintained at a pH value in the range of about 4 to about 7.

[0009] According to various embodiments, the mesophilic aerobic digestion of the biodegradable packaging waste can be maintained at a dissolved oxygen level in the range of about 2 mg / L to about 3 mg / L. According to various embodiments, the method may further include receiving biodegradable packaging waste in a tank having a top and a bottom below the top, supplying air into the tank, injecting mesophilic microorganisms into the tank, and transporting the biodegradable packaging waste from the tank to a biological valorization system.

[0010] According to various embodiments, the method may further include aerating the biodegradable packaging waste and advancing the biodegradable packaging waste from the top of the tank towards the bottom. According to various embodiments, the method may further include circulating the biodegradable packaging waste from the bottom of the tank to the top.

[0011] According to various embodiments, there is provided an apparatus for treating biodegradable packaging waste before subjecting the biodegradable packaging waste to a biological valorization process. The apparatus includes a tank for receiving the biodegradable packaging waste therein, the tank having a top and a bottom below the top, an air supply module adapted to supply air to the tank, and a microorganism injector adapted to inject mesophilic microorganisms into the tank such that the tank is adapted to receive the biodegradable packaging waste, air, and mesophilic microorganisms, and the biodegradable packaging waste is subjected to mesophilic aerobic digestion before being transported from the tank to a biological valorization system to subject the biodegradable packaging waste to a biological valorization process.

[0012] According to various embodiments, the apparatus may further include a temperature module configured to maintain the mesophilic aerobic digestion of the biodegradable packaging waste at a temperature in the range of about 20°C to about 45°C. According to various embodiments, the apparatus may further include a pH module configured to maintain the mesophilic aerobic digestion of the biodegradable packaging waste at a pH value in the range of about 4 to about 7.

[0013] According to various embodiments, the air supply module may be configured to supply air into the tank to maintain the mesophilic aerobic digestion of biodegradable packaging waste at a dissolved oxygen level in the range of about 2 mg / L to about 3 mg / L.

[0014] According to various embodiments, the apparatus may further include a surface aeration device disposed within the tank, the surface aeration device being adapted to aerate the biodegradable packaging waste and advance the biodegradable packaging waste at the top of the waste towards the bottom of the waste.

[0015] According to various embodiments, the apparatus may further include a circulation mechanism fluidly connected to the tank and adapted to circulate the biodegradable packaging waste from the bottom of the waste to the top of the waste. According to various embodiments, the tank may be insulated.

[0016] According to various embodiments, a method of digesting biodegradable packaging waste is provided. The method includes subjecting the biodegradable packaging waste to mesophilic aerobic digestion and then subjecting the biodegradable packaging waste to a biological valorization process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

[0018] In the following examples, reference is made to the drawings, in which the same features are denoted by the same numbers. Figure 1 shows an exemplary method 1000 for treating biodegradable packaging waste before subjecting the biodegradable packaging waste to a biological valorization process. The method includes, at block 1020, subjecting the biodegradable packaging waste to mesophilic aerobic digestion, before the step, at block 1040, of subjecting the biodegradable packaging waste to a biological valorization process. In other words, the method includes a method of digesting the biodegradable packaging waste by subjecting the biodegradable packaging waste to mesophilic aerobic digestion and then subjecting the biodegradable packaging waste to a biological valorization process.

[0019] The biodegradable packaging waste is pretreated by mesophilic aerobic digestion before subjecting the treated biodegradable packaging waste to a biological valorization process. In this way, the biodegradable packaging waste is converted into a viable feedstock for the biological valorization process. The biological valorization process may include enzymatic hydrolysis, fermentation, anaerobic digestion, or composting, such as industrial composting.

[0020] The method may consist only of the step of subjecting the biodegradable packaging waste to mesophilic aerobic digestion before subjecting the biodegradable packaging waste to a biological valorization process, without additional steps for digesting the biodegradable packaging waste. In other words, the method may consist only of the step of subjecting the biodegradable packaging waste to mesophilic aerobic digestion and then the subsequent step of subjecting the biodegradable packaging waste to a biological valorization process, without additional steps for digesting the biodegradable packaging waste. Different from known methods that carry out multi-stage digestion, such as aerobic and anaerobic digestion or periodic aerobic and anaerobic digestion stages, the method consists only of a single stage of mesophilic aerobic digestion before a single stage of the biological valorization process, and not vice versa.

[0021] By subjecting biodegradable packaging waste to mesophilic aerobic digestion, the waste is broken down into smaller constituent units using aerobic microbial treatment so that the waste can be digested by anaerobic microorganisms. For example, biodegradable materials such as pulp-based materials (e.g., paper, molded fibers) and bioplastics such as polylactic acid (PLA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polybutylene succinate (PBS), and thermoplastic starch (TPS) can be mentioned as biodegradable packaging waste, but are not limited thereto. The waste may be broken down into smaller constituent units such as lignin, cellulose, lactic acid (LA), glucose, and volatile fatty acids (VFA), which can be anaerobically digested. Using this method, a higher yield of biogas can be obtained from anaerobic digestion, that is, the amount of biogas per unit of mixed waste increases.

[0022] Furthermore, by subjecting biodegradable packaging waste to mesophilic aerobic digestion, it is possible to digest the treated biodegradable packaging waste or constituent units using mesophilic anaerobic digestion instead of conventional anaerobic thermophilic digestion. By using mesophilic anaerobic digestion, it is possible to digest the waste at a temperature in the range of about 20°C to about 45°C. Compared with the temperature of thermophilic anaerobic digestion in the range of 45°C to about 120°C, this method does not require strong energy consumption and saves energy when digesting biodegradable packaging waste aerobically and anaerobically.

[0023] In addition to energy savings, the method accelerates the decomposition of biodegradable packaging waste. Typically, food waste takes about 20 - 30 days to decompose anaerobically, and biodegradable packaging waste takes a considerably longer period, for example, 120 days. By using this method to pretreat biodegradable packaging waste prior to the biological valorization process, the time required to decompose the waste is dramatically reduced to about 20 - 30 days, i.e., approximately the same period as the decomposition of food waste. Thus, it becomes possible to decompose biodegradable packaging waste together with food waste, eliminating the need for waste separation. In this way, decomposing mixed waste by a biological valorization process, such as anaerobic digestion, is more commercially sustainable and practical. Overall, the method shortens the time required to digest biodegradable packaging waste, thus saving energy, time, and cost.

[0024] Mesophilic aerobic digestion uses a mixture of microbial communities to digest biodegradable packaging waste, so this method does not require the addition of catalysts or additives. Thus, materials, energy, and costs are significantly saved.

[0025] The microbial community may include a mixture of microorganisms with the property of decomposing specific substances (for example, microorganisms capable of decomposing PLA). Thus, the microbial community can target specific packaging materials. There may be two or more microbial communities, and each microbial community consists of microbial strains capable of synthesizing the appropriate enzymes required to hydrolyze specific packaging materials in the waste.

[0026] FIG. 2 shows an exemplary embodiment of an apparatus 100 for treating biodegradable packaging waste before subjecting the biodegradable packaging waste to a biological valorization process. The apparatus 100 includes a tank 210 for receiving the biodegradable packaging waste therein, the tank 210 having a top 210T and a bottom 210B below the top 210T, an air supply module 220 adapted to supply air to the tank 210, and a microorganism injector 230 adapted to inject mesophilic microorganisms into the tank 210 such that the tank 210 is adapted to receive the biodegradable packaging waste, air, and mesophilic microorganisms therein. The biodegradable packaging waste is subjected to mesophilic aerobic digestion before being transported from the tank 210 to a biological valorization system 20 to subject the biodegradable packaging waste to a biological valorization process. In the tank 210, the biodegradable packaging waste is subjected to the method 1000 shown in FIG. 1. The apparatus 100 may include a biological valorization system 20.

[0027] Figure 3 shows another exemplary embodiment of apparatus 300. Apparatus 300 may receive biodegradable packaging waste as waste feedstock 30 conveyed into tank 310. Waste feedstock 30 may include mixed waste, i.e., food waste and biodegradable packaging waste. Waste feedstock 30 may be directly supplied to tank 310 via transport device 350. Transport device 350 may include a conveyor belt, a pressure conduit, and the like. As shown in FIG. 2, transport device 350 may include pump 352 along inlet conduit 354 connected to tank 310 and is adapted to pump waste feedstock 30 from a feedstock source into tank 310. Waste feedstock 30 may be in a sludge form. Apparatus 300 may include grinder 356 adapted to grind waste feedstock 30 to a smaller particle size before transporting waste feedstock 30 to tank 310. Grinder 356 may be connected to transport device 350 to receive the feedstock and may be connected to tank 310 to convey the ground waste feedstock 30 to tank 310. Apparatus 300 may include level sensor 358 configured to sense the level of waste in tank 310. Apparatus 300 may include a waste control module (not shown in FIG. 3) in communication with transport device 350 and level sensor 358 and configured to control the level of waste in tank 310. The waste control module is configured to receive a signal from level sensor 358 and transmit a control signal to transport device 350. When level sensor 358 detects that the waste level is below a predetermined level, the waste control module is configured to activate transport device 350 to convey feedstock 30 into tank 310.

[0028] The air supply module 320 may include a dissolved oxygen (DO) sensor 322 configured to sense the amount of dissolved oxygen level in the waste within the tank 310, an air pump 352 adapted to transport air or oxygen into the tank 310 by a pump 352, and a DO controller configured to communicate with the DO sensor and the pump 352 and control the dissolved oxygen level in the waste. The DO controller is configured to receive a signal from the DO sensor and transmit a control signal to the air pump 352. When the DO sensor senses the dissolved oxygen level in the waste, it transmits a signal to the DO controller. When the level of dissolved oxygen is less than a predetermined level, the DO controller is configured to activate the air pump 352 to pump air or oxygen into the tank 310. The air supply module 320 may be configured to supply air into the tank 310 to maintain the mesophilic aerobic digestion of biodegradable packaging waste at a dissolved oxygen level in the range of about 2 mg / L to about 3 mg / L. The air supply module 320 is configured to continuously monitor the dissolved oxygen level in the waste and supply air when necessary to maintain the level at a predetermined level. To keep the microorganisms alive, the dissolved oxygen in the waste can be maintained above 2 mg / L. Although it is possible to maintain the dissolved oxygen level above 3 mg / L, the dissolved oxygen level is maintained below 3 mg / L to reduce the energy consumption. The air supply module 320 may include a backup air pump 352 (not shown in FIG. 3) that communicates with the DO controller so that the backup air pump can be activated when the air pump 352 fails.

[0029] The microorganism injector 230 may include a culture tank (not shown in FIG. 3) that houses aerobic microorganisms and an injection pump (not shown in FIG. 3) adapted to inject the aerobic microorganisms from the culture tank into the tank 310. The injection pump may be configured to inject various dosages of aerobic microorganisms and may be controlled to inject at various rates required for the waste.

[0030] The device 300 may include a temperature module 370 configured to maintain the mesophilic aerobic digestion of biodegradable packaging waste at a temperature within a certain range. The temperature module 370 may include a temperature sensor 372 configured to sense the temperature within the tank 310, a heating element 374 adapted to heat the tank 310, and a temperature controller 376 in communication with the temperature sensor 372 and the heating element 374 and configured to control the temperature within the tank 310. The heating element 374 may be disposed within the tank 310 or around the tank 310, such as in a heating jacket. The heating element 374 may be disposed above or within the waste. The temperature sensor 372 may be disposed within the waste and configured to sense the temperature of the waste. The tank 310 may be insulated to prevent heat within the tank 310 from escaping to the surroundings. The temperature controller 376 is configured to receive a signal from the temperature sensor 372 and transmit a control signal to the heating element 374 to heat the tank 310. When the temperature sensor 372 senses the temperature within the tank 310, it transmits a signal to the temperature controller 376. When the temperature is below a predetermined lower limit temperature, the temperature controller 376 is configured to activate the heating element 374 to heat the tank 310. Similarly, when the temperature exceeds a predetermined upper limit temperature, the temperature controller 376 is configured to stop the heating element 374 to stop heating the waste. The temperature module 370 may be configured to maintain the mesophilic aerobic digestion of biodegradable packaging waste at a temperature in the range of about 20°C to about 45°C. Preferably, the temperature is maintained at about 20°C to about 40°C to reduce energy consumption. Ideally, the temperature is maintained at 20°C to about 30°C. The temperature module 370 is configured to continuously monitor the temperature within the tank 310 and heat the tank 310 when necessary to maintain the temperature within the tank 310 at a predetermined temperature. Since the digestion is exothermic, the heat released from the digestion of the waste may be sufficient to maintain the temperature of the waste within the insulated tank 390. Therefore, there is no need to heat the waste, and energy is conserved.

[0031] The device 300 may include a pH module 380 configured to maintain the mesophilic aerobic digestion of biodegradable packaging waste within a range of pH values. The pH module 380 may include a pH sensor 382 configured to sense the pH value of the waste, a solution storage tank 384 adapted to store at least one pH adjustment solution, a dosing pump 386 adapted to pump at least one adjustment solution from the storage tank 384 to the tank 310 by a pump 352, and a pH controller 388 in communication with the pH sensor 382 and the dosing pump 386 and configured to control the pH value in the waste. The solution may be an acid or an alkali, or both, if there are more than one adjustment solutions. The pH controller is configured to receive a signal from the pH sensor 382 and send a control signal to the dosing pump 386 to pump the required amount of adjustment solution into the tank 310. When the pH sensor 382 senses the pH value in the waste, it sends a signal to the pH controller. When the pH value is below a predetermined lower limit value, the pH controller is configured to operate the dosing pump 386 to pump an alkali into the tank 310. Similarly, when the pH value exceeds a predetermined upper limit value, the pH controller is configured to operate the dosing pump 386 to pump an acid into the tank 310. The pH module 380 may be configured to maintain the mesophilic aerobic digestion of biodegradable packaging waste at a pH value in the range of about 4 to about 7 to ensure effective digestion of the waste. Preferably, the pH value of the waste is maintained at about 5 to about 6.5 for an optimal degradation rate. The pH module 380 is configured to continuously monitor the pH value of the waste and pump the appropriate amount of adjustment solution when necessary to maintain the pH value of the waste at a predetermined pH value.

[0032] The device 300 may further include a surface aeration device 390 disposed within the tank 310, whereby the surface aeration device 390 is adapted to aerate the biodegradable packaging waste and advance the biodegradable packaging waste at the top of the waste towards the bottom of the waste. The surface aeration device 390 may be disposed at a position within the tank 310 at the top of the waste such that the surface aeration device 390 can contact the top of the waste and advance the top of the waste towards the bottom 310B of the tank 310. Thus, the surface aeration device 390 may be at the top 310T of the tank 310, or at the intermediate portion 310M between the top 310T and the bottom 310B. By aerating the waste, the surface aeration device 390 increases the level of dissolved oxygen within the waste such that aerobic microbial activity occurs. Aerobic microorganisms tend to form aggregates, and the aggregates tend to settle to the bottom of the tank 310. Unlike conventional aeration methods that introduce air from the bottom of the tank 310 to generate bubbles and thus float low-density waste to the top of the waste and interfere with microbial activity, the surface aeration device 390 agitates and pushes down waste that would otherwise float on the surface of the waste within the tank 310 such that the aerobic microorganisms can be more uniformly mixed with the waste. Further, the agitation also helps to break down the aggregates such that the microorganisms are more uniformly dispersed within the tank 310. This is particularly important for strains of microorganisms that have limited or no motility and do not have flagella that rely on externally induced agitation to reach the waste. The surface aeration device 390 may be configured to rotate at various speeds in order to accommodate the mixing rate required to mix the waste with the added conditioning solution, oxygen, and microorganisms. The surface aeration device 390 may include an impeller that rotates about a vertical axis and is adapted to advance the top waste towards the bottom.

[0033] The apparatus 300 may include a circulation mechanism 360 that is in fluid communication with the tank 310 and is adapted to circulate the biodegradable packaging waste from the bottom of the waste to the top of the waste. The circulation mechanism 360 may include a duct 362 that is in fluid communication with the tank 310 such that one end of the duct 362 is connected to the bottom 310B of the tank 310 and the other end of the duct 362 is connected to the top 310T or the middle portion 310M of the tank 310 and above the waste. The circulation mechanism 360 may include a circulation pump 364 connected to the duct 362 and adapted to pump the waste from the bottom 310B to the top 310T or the middle portion 310M, whereby the bottom of the waste is transferred to the top of the waste. In addition to the surface aeration device 390, the circulation of the waste increases the level of dissolved oxygen in the waste so that aerobic microbial activity occurs. Since aerobic microorganisms tend to form aggregates and the aggregates tend to settle to the bottom of the tank 310, circulating the waste ensures that the waste is well mixed and the aggregates at the bottom 310B of the tank 310 are transferred to the top of the waste. Also, the addition of waste to the top of the waste helps to push down the top of the waste, which may have floating matter. The circulation pump 364 may pump at various speeds to vary the rate of circulation of the waste.

[0034] The tank 310 may include a discharge port 310P disposed at the bottom 310B of the tank 310 and adapted to discharge the waste from the tank 310. The discharged waste may be transported to the biological valorization system 20. The discharge port 310P may be connectable to a conduit connected to the biological valorization system 20 such that the waste can be conveyed to the biological valorization system 20 through the discharge port 310P and the conduit. The biological valorization system 20 may be part of an anaerobic digestion plant or an industrial composting plant.

[0035] The apparatus 300 may include a computer device (not shown in FIG. 3) that communicates with modules, such as an air supply module 320, a temperature module 370, and a pH module 380. The computer device is configured to receive data and monitoring parameters from the modules. The computer device is configured to record the data and parameters in a database. The computer device may include program modules configured to control the modules. The computer device may be configured to control the microbial injector 330 to inject aerobic microorganisms at programmed times, rates, and dosages. The apparatus 300 may include a programmable logic controller (PLC) configured to control components within the apparatus 300, such as the surface aeration device 390, based on a pre-programmed process. For example, when pH adjustment is required, the dosing pump injects the adjustment solution (base or acid) at a controlled rate, and the surface aeration device 390 and the circulation pump 364 operate simultaneously at a higher rate to ensure as rapid as possible a uniform distribution throughout the waste of the adjustment solution containing the microorganisms. In this way, the waste can be made as homogeneous as possible so that the pH sensor can measure the exact pH value of the waste at any point in time. Thus, it is possible to obtain accurate and rapid readings of the pH value of the waste and to inject the appropriate and accurate amount of adjustment solution to maintain an optimal state for the growth of aerobic microorganisms.

[0036] Figure 4 shows an exemplary embodiment of the tank 410. The tank 410 may include an input port 410N and an output port 410U for allowing waste to enter and exit the tank 410. The input port 410N may be disposed at the top 410T of the tank 410 above the output port 410U that may be at the bottom 410B of the tank 410. The input port 410N and the output port 410U may be connectable to a circulation mechanism (not shown in FIG. 4) for pumping the bottom of the waste from the output port 410U through the input port 410N to the top of the waste. The tank 410 may include an inlet 410E for receiving waste therein and a discharge port 410P for discharging the waste. The inlet 410E may be disposed at the top 410T or the middle part 410M, or may simply be disposed above the waste level. The base of the tank 410 may be tapered to direct the waste towards the discharge port 410P. The tank 410 may include a probe port 410R for a sensor inserted into the tank 410. There may be at least three probe ports 410R for the temperature sensor 372, the pH sensor 382, and the DO sensor. The tank 410 may include at least one sampling port 410S for a sample of the waste to be tested or extracted. The sampling port 410S may be disposed at the top 410T, the bottom 310B, and / or the middle part 310M of the tank 410. As described above, the surface aeration 490 and a level sensor (not shown in FIG. 4) may be disposed within the tank 410, and the heating element 474 may be disposed within or around the tank 410.

[0037] To digest biodegradable packaging waste, the waste feedstock 30 may be conveyed to the tank 310 via the transport device 350. The waste feedstock 30 may be crushed to a smaller particle size by the crusher 356 before entering the tank 310 through the inlet. In the tank 310, the waste is filled to a predetermined level and data and parameters of the waste are acquired. If the temperature of the waste is below a predetermined temperature, the device 300 can activate the heating element 374 to heat the waste to the predetermined temperature. If the pH value of the waste is not at a predetermined value, the device can activate the dosing pump 386 to introduce a solution into the waste. If the dissolved oxygen level is below a predetermined value, the device 300 can activate the air pump 324 to supply air or oxygen to the tank to increase the oxygen level in the tank 310. At the same time, the device 300 can activate the microorganism injector 330 to inject aerobic microorganisms into the waste. During that time, the surface aeration device 390 is activated to stir and propel the waste, and the circulation mechanism 360 is activated to circulate the bottom of the waste to the top of the waste. The device 300 may vary at least the rotation speed of the surface aeration device 390, the pump flow rate of the circulation pump 364, the dosing amount of the conditioning solution, and the aerobic microorganisms as needed. The waste may be treated in the tank 310 for up to 7 days before being conveyed to the biological valorization system 20. Preferably, the waste may be treated in the tank 310 for 2 to 3 days. Thereafter, the treated waste may be discharged from the tank 310 and conveyed to the biological valorization system 20.

[0038] Those skilled in the art will understand that the features described in one example may not be limited to that example and may be combined with any one of the other examples. The present invention relates to a method and a system for treating biodegradable packaging waste before subjecting the biodegradable packaging waste to a biological valorization process as generally described herein with reference to the accompanying drawings and / or illustrated in the accompanying drawings.

Claims

1. A method for treating biodegradable packaging waste before subjecting the biodegradable packaging waste to a biological valorization process, the method comprising the step of subjecting the biodegradable packaging waste to mesophilic aerobic digestion before subjecting the biodegradable packaging waste to the biological valorization process.

2. The method according to claim 1, wherein the mesophilic aerobic digestion of the biodegradable packaging waste is maintained at a temperature in the range of about 20°C to about 45°C.

3. The method according to claim 1 or 2, wherein the mesophilic aerobic digestion of the biodegradable packaging waste is maintained at a pH value in the range of about 4 to about 7.

4. The method according to any one of claims 1 to 3, wherein the mesophilic aerobic digestion of the biodegradable packaging waste is maintained at a dissolved oxygen level in the range of about 2 mg / L to about 3 mg / L.

5. The method according to any one of claims 1 to 4, further comprising the steps of receiving the biodegradable packaging waste in a tank having a top and a bottom below the top, supplying air into the tank, injecting mesophilic microorganisms into the tank, and transporting the biodegradable packaging waste from the tank to a biological valorization system.

6. The method according to claim 5, further comprising the steps of aerating the biodegradable packaging waste and advancing the biodegradable packaging waste from the top of the tank towards the bottom.

7. The method according to claim 6, further comprising the step of circulating the biodegradable packaging waste from the bottom of the tank to the top.

8. An apparatus for treating biodegradable packaging waste before subjecting the biodegradable packaging waste to a biological valorization process, a tank for receiving the biodegradable packaging waste therein, the tank having a top and a bottom below the top, an air supply module adapted to supply air into the tank, and a microorganism injector adapted to inject mesophilic microorganisms into the tank, wherein the tank is adapted to receive the biodegradable packaging waste, air, and mesophilic microorganisms therein, and the biodegradable packaging waste is subjected to mesophilic aerobic digestion before being transported from the tank to a biological valorization system to subject the biodegradable packaging waste to the biological valorization process.

9. The apparatus according to claim 8, further comprising a temperature module configured to maintain the mesophilic aerobic digestion of the biodegradable packaging waste at a temperature in the range of about 20°C to about 45°C.

10. The apparatus according to claim 8 or 9, further comprising a pH module configured to maintain the mesophilic aerobic digestion of the biodegradable packaging waste at a pH value of about 4 to about 7.

11. The apparatus according to any one of claims 8 to 10, wherein the air supply module is configured to supply air into the tank to maintain the mesophilic aerobic digestion of the biodegradable packaging waste at a dissolved oxygen level in the range of about 2 mg / L to about 3 mg / L.

12. The apparatus according to any one of claims 8 to 11, further comprising a surface aeration device disposed within the tank, the surface aeration device being adapted to aerate the biodegradable packaging waste and to advance the biodegradable packaging waste from the top of the waste towards the bottom of the waste.

13. The apparatus according to any one of claims 8 to 12, further comprising a circulation mechanism in fluid communication with the tank and adapted to circulate the biodegradable packaging waste from the bottom of the waste to the top of the waste.

14. The apparatus according to any one of claims 8 to 13, wherein the tank is insulated.

15. A method for digesting biodegradable packaging waste, comprising: subjecting the biodegradable packaging waste to mesophilic aerobic digestion; and subsequently subjecting the biodegradable packaging waste to a biological valorization process.

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