Systems and methods for processing mixed solid waste
Solid waste that includes a mixture of wet organic material and dry organic material can be are separated using mechanical separation to produce a wet organic stream enriched in wet organics and a dry organic stream enriched in dry organics. The separated wet organic stream and dry organic stream are separately converted to renewable or recyclable products using different conversion techniques particularly suited for the separated wet and dry organic streams.
1. A method for processing mixed solid waste, comprising:
providing a mixed waste stream comprising at least 10 wt % wet organic waste and at least 10 wt % dry organic waste that is comingled, wherein the dry organic waste includes fiber and plastic;
fractionating the mixed waste stream by size to produce one or more sized waste streams, each sized waste stream having an upper size cut and a lower size cut where the ratio of an upper cut-off to a lower cut-off is less than 8; and
fractionating the one or more sized waste stream by density to produce a plurality of intermediate waste streams having different densities, the plurality including at least a first intermediate waste stream that includes fiber and plastic;
sorting the first intermediate stream to produce a sorted fiber material or a sorted plastic material;
converting the sorted fiber material or sorted plastic material to one or more renewable products; and
converting at least a portion of a second waste stream of the plurality to one or more renewable products using a first conversion technique.
2. A method as in claim 1 , wherein less than 40 wt % of the mixed waste stream is separated as a recovered product using manual labor.
3. A method as in claim 1 , wherein less than 1 wt % of the mixed waste stream is separated as a recovered product using manual labor.
4. A method as in claim 1 , wherein the mixed waste stream includes at least 15% dry organic waste and at least 30% wet organic waste.
5. A method as in claim 1 , wherein at least 10 wt % of the mixed waste stream is dry organic waste selected from the group consisting of 3-D plastic, film plastic, paper, cardboard, rubber, textiles, and wood.
6. A method as in claim 1 wherein at least 10 wt % of the mixed waste stream is a wet organic waste selected from the group consisting of food waste, animal waste, and green waste.
7. A method as in claim 1 , wherein the throughput of the mixed waste stream is at least 10 metric tons per hour per single line of mixed solid waste.
8. A method as in claim 1 , wherein the first conversion technique is selected from wet digestion, dry digestion, anaerobic digestion or composting.
9. A method as in claim 8 , wherein the first conversion technique produces biogas.
10. A method as in claim 1 , wherein the mixed waste stream includes at least 20% by weight of low value material selected from the group consisting of wet organics, green waste, food waste, grit, fines less than 1 inch, asphalt, concrete, textiles, wood, rubber, film plastic, PVC, foil, rock, used consumer products, low value glass, composite materials, and combinations of these.
11. A method as in claim 1 , wherein sorting the first intermediate waste stream includes separating 3-dimensional plastics from 2-dimensional plastics.
12. A method as in claim 11 , wherein the 2-dimensional plastic is converted to a fuel and the 3-dimensional plastic is recycled to form a plastic product.
13. The method of claim 1 , wherein the sorted fiber is made into paper using a paper pulping process.
14. The method of claim 1 , wherein the sorted plastic includes PETE and is converted into PETE bottles.
15. The method of claim 1 , wherein the sorted plastic includes PETE and is converted to an insulation product.
16. The method of claim 1 , wherein the sorted plastic includes HDPE and is converted to an HTPE bottle or a packaging material.
17. The method of claim 1 , further comprising recovering aluminum from one or more of the plurality of intermediate waste streams.
18. The method of claim 17 , further comprising producing aluminum ingot from the recovered aluminum.
19. The method of claim 1 , wherein the sorted fiber is made into paper using a paper pulping process.
20. A method for processing mixed solid waste, comprising:
providing a mixed waste stream comprising at least 20 wt % wet organic waste and at least 20 wt % dry organic waste that is comingled, wherein the dry organic waste includes fiber and plastic;
fractionating the mixed waste stream by size to produce one or more sized waste streams, each sized waste stream having an upper size cut and a lower size cut where the ratio of an upper cut-off to a lower cut-off is less than 8; and
fractionating the one or more sized waste stream by density to produce at least three intermediate waste streams having different densities, wherein at least a first intermediate waste stream includes fiber and plastic;
sorting the first intermediate stream using a plurality of optical sorters to produce a sorted fiber material or a sorted plastic material;
converting the sorted fiber material or sorted plastic material to one or more renewable products;
converting at least a portion of the second waste into a second renewable product; and
recovering aluminum from at least a portion of the three intermediate waste streams.