Hint #3: All of the material separated out by the magnet (extract) goes to the roll crusher. All of the material separated out by the air classifier goes to the shredder. 4. Using your matrix with the chosen order of separation processes from #2, estimate the quantity (mass/day) and purity of the 5 materials recovered (paper, steel, glass, aluminum, and plastics). (Purity of paper was already determined in 2.) The quantity recovered for sale is what ends up in the target extract only (paper separated by the air classifier only, for example). 5. Estimate the amount of waste from the MRF that must go to the landfill, as all materials are not recovered. The waste that must go to the landfill is the waste that passes through the last separation process, without being separated out (reject). 6. Estimate the critical speed of the trommel screen (2.75 m diameter). 7. Calculate the characteristic size of the shredder, assuming that it must produce a product such that 95% of the material passes the 1" sieve (n=1.15). 8. Calculate the velocity in the air classifier needed to suspend the paper pieces, assuming a 4" aerodynamic diameter. Density of paper waste = 800 lb/yd³, C₁ = 2.5, void fraction = 55%. (2 points) 9. Calculate the size of rollers required for the roll crusher. Use 7.4 cm for the can diameter. Desired crushed particle size = 0.9 cm. Coefficient of kinetic friction for steel on steel is 0.57. Calculate the roller width W needed to meet the required capacity. Assume M = 42 rpm and p = 250 lb/yd³. Part 2. SWOLF Life Cycle Inventory Modeling 11. Use SWOLF to compare the 2 options A and B. For option A, you will only be able to have the yard waste and food waste go to the digester. You will need to run the model twice. SWOLF will provide output to compare the 2 options in terms of total cost, total greenhouse gas emissions, and percent diverted. Create a table of your own to summarize the comparison. 12. Use a decision-making matrix with weightings and ratings to compare the 2 options A and B based on the quantitative values in the table created in #11, as well as your semi-quantitative assessment of the following: air emissions (besides greenhouse gases), • water pollution potential, water use, ⚫ land impacts, and ⚫ any other appropriate factors. Explain your weightings of all criteria, and your ratings of the semi-quantitative criteria based on information about the options discussed in class. Based on your decision-making matrix, which option would you recommend?

Hint #3: All of the material separated out by the magnet (extract) goes to the roll crusher. All of the material separated out by the air classifier goes to the shredder. 4. Using your matrix with the chosen order of separation processes from #2, estimate the quantity (mass/day) and purity of the 5 materials recovered (paper, steel, glass, aluminum, and plastics). (Purity of paper was already determined in 2.) The quantity recovered for sale is what ends up in the target extract only (paper separated by the air classifier only, for example). 5. Estimate the amount of waste from the MRF that must go to the landfill, as all materials are not recovered. The waste that must go to the landfill is the waste that passes through the last separation process, without being separated out (reject). 6. Estimate the critical speed of the trommel screen (2.75 m diameter). 7. Calculate the characteristic size of the shredder, assuming that it must produce a product such that 95% of the material passes the 1" sieve (n=1.15). 8. Calculate the velocity in the air classifier needed to suspend the paper pieces, assuming a 4" aerodynamic diameter. Density of paper waste = 800 lb/yd³, C₁ = 2.5, void fraction = 55%. (2 points) 9. Calculate the size of rollers required for the roll crusher. Use 7.4 cm for the can diameter. Desired crushed particle size = 0.9 cm. Coefficient of kinetic friction for steel on steel is 0.57. Calculate the roller width W needed to meet the required capacity. Assume M = 42 rpm and p = 250 lb/yd³. Part 2. SWOLF Life Cycle Inventory Modeling 11. Use SWOLF to compare the 2 options A and B. For option A, you will only be able to have the yard waste and food waste go to the digester. You will need to run the model twice. SWOLF will provide output to compare the 2 options in terms of total cost, total greenhouse gas emissions, and percent diverted. Create a table of your own to summarize the comparison. 12. Use a decision-making matrix with weightings and ratings to compare the 2 options A and B based on the quantitative values in the table created in #11, as well as your semi-quantitative assessment of the following: air emissions (besides greenhouse gases), • water pollution potential, water use, ⚫ land impacts, and ⚫ any other appropriate factors. Explain your weightings of all criteria, and your ratings of the semi-quantitative criteria based on information about the options discussed in class. Based on your decision-making matrix, which option would you recommend?

Solid Waste Engineering

3rd Edition

ISBN:9781305635203

Author:Worrell, William A.

Publisher:Worrell, William A.

Chapter5: Separation Processes

Section: Chapter Questions

Problem 5.18P

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