Integrated Strategy Example: Mass Burning of MSW with Electricity Generation and Ash Disposal in a Monofill

To illustrate the application of the data on technologies to the evaluation of options for an integrated MSW management strategy, this section compares the energy balance and air and water emissions for two strategies:

Table 5.3 shows the energy and emissions over a 20-year period for an integrated MSW management strategy that relies on mass burning MSW. The estimates in the table include not only energy and emissions for collection and mass burning, but also the emissions from the leachate from the ash landfill, as well as the contribution of landfilling to the energy and emissions for the strategy as a whole. The results are given separately for transportation, processing (mass burning), and disposal (landfilling the ash). Table 5.4 presents the same data for the landfill strategy.

Mass burning produces about four times more energy per ton of MSW than is recovered from a landfill. Air emissions from mass burning include much smaller quantities of organics, but much larger quantities of metals, than air emissions from landfills. Ash monofills produce smaller quantities of leachate than landfills, and the leachate has a lower metals content as well. Strategies that include mass burning and shred-and-burn RDF require smaller volumes of landfill space than any other strategy, especially if the combustion strategy also includes separation and recycling.

For the nation as a whole, an average of 2-4% of the weight of incoming refuse is ferrous metals recovered for recycling from the ash. The energy saved by recycling the metal is an additional 0.36 million Btu per ton of MSW, or 4% of the net energy recovered by mass burning (see Exhibit II). That savings is not included in the data base.

Other Integrated Strategies Described in the Data Base

The computerized data base permits users to integrate RDF production and direct combustion with other MSW technologies to determine the energy and environmental implications of any integrated MSW management strategy. Exhibit II and the computerized data base provide calculations for the following important integrated strategies that include mass burning:

                                                                Table 5.3
                                 ENERGY AND EMISSIONS FOR STRATEGY 2: MASS BURN

                                      Total  Collection  Process(a) Disposal

Landfill space for residue (assuming a
  depth of 50 ft., 10(-5) acres             0.27                                0.27
Solid waste (lb)                            545                                 545
Energy Required (million Btu)               1.59       0.079        1.51       0.0003
Energy Produced (million Btu)               10.3        0.00       10.30        0.00
Net Energy                                  8.70       -0.079       8.78       0.0003

Air Emissions
Particulates (lb)                           0.08        0.02       0.066
Carbon Monoxide (lb)                        1.47        0.79        0.63
Hydrocarbons (lb)                          0.079       0.079         NA         0.00
Nitrogen Oxides (lb)                        5.11        0.32        4.79
Carbon dioxide (lb)                         1650                    1650
Water (lb)                                  1140                    1140
Methane (lb)                                 0
NMOC (lb)                                    0
Dioxin/furan {10(-6)lb}                    0.014                   0.014
SO(2)                                       2.45                    2.45
HCI                                         1.40                    1.40
Antimony {10(-6)lb}                          NA                      NA
Arsenic {10(-6)lb}                          4.1                     4.1
Cadmium {10(-6)lb}                          8.0                     8.0
Chromium {10(-6)lb}                          19                      19
Lead {10(-6)LB}                              10                      10
Mercury {10(-6)LB}                          230                     230
Nickel {10(-6)LB}                            17                      17
Zinc {10(-6)LB}                              NA                      NA
Total Heavy Metals {10(-6)lb}               288                     288

Leachate (gal)                               10                                  10
Leachate(lb)                                 84                                  84
Chloride (lb)                               1.17                                1.17
Sodium (lb)                                 0.26                                0.26
Potassium (lb)                              0.14                                0.14
TOC (lb)                                   0.0003                              0.0003
Arsenic {10(-3)lb}                           ND                                  ND
Cadmium {10(-3)lb}                           ND                                  ND
Chromium {10(-3)lb}                          ND                                  ND
Copper {10(-3)lb}                            ND                                  ND
Nickel {10(-3)lb}                            ND                                  ND
Lead {10(-3)lb}                              ND                                  ND
Mercury {10(-3)lb}                           ND                                  ND
Zinc{10(-3)lb}                               ND                                  ND
Total Heavy Metals {10(-3)lb}                ND                                  ND
AOX (gal)                                    ND                                  ND

(a) Mass burn
(b) This is total dioxin/furan as specified by EPA in CFR, 1991a
Click here for table in WK1 format.

                                           Table 5.4


                                       Total   Collection  Process  Disposal

Landfill space (assuming a depth of
  50 ft), 10(-5) acres                         2.00                                2.00
Solid waste (lb)                               2000                                2000
Energy Required (million Btu)                 0.081       0.079                   0.002
Energy Produced (million Btu)                  2.20        0.00                    2.20
Net Energy (million Btu)                       2.12       -0.079                   2.20

Air Emissions
Particulates (lb)                              0.02        0.02
Carbon Monoxide (lb)                           0.79        0.79
Hydrocarbons (lb)                              0.08        0.08
Nitrogen oxides (lb)                           0.32        0.32                     NA
Carbon dioxide (lb)                            225                                 225
Carbon dioxide-combustion (lb)                 212                                 212
Water (lb)                                     188                                 188
Methane (lb)                                  14.34                               14.34
NMOC (lb)                                      0.75                                0.75
Dioxin/furan {10(-6)lb}(a)
SO(2) {10(-3)lb}
HCI {10(-3)lb}
Antimony {10(-6)lb}
Arsenic {10(-6)lb}
Cadmium {10(-6)lb}
Chromium {10(-6)lb}
Lead {10(-6)lb}
Mercury {10(-6)lb}
Nickel {10(-6)lb}
Zinc {10(-6)lb}
Total Heavy Metals {10(-6)lb}                   NA                                  NA

Leachate(gal)                                   80                                  80
Leachate(lb)                                   667                                 667
Chloride                                       1.13                                1.13
Sodium (lb)                                    0.73                                0.73
Potassium (lb)                                 0.60                                0.60
COD (lb)                                       0.16                                0.16
Arsenic {10(-3)lb}                              86                                  86
Cadmium {10(-3)lb}                              3                                   3
Chromium {10(-3)lb}                            163                                 163
Copper {10(-3)lb}                               43                                  43
Nickel {10(-3)lb}                              108                                 108
Lead {10(-3)lb}                                 48                                  48
Mercury {10(-3)lb}                              6                                   6
Zinc {10(-3)lb}                                 NA                                  NA
Total Heavy Metals {10(-3)lb}                  457                                 457
AOX (lb)                                       1.08                                1.08

(a) This is total dioxin/furan as specified by EPA in CFR, 1991a.
Click here for table in WK1 format.

Refuse-Derived Fuel


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