Integrated Strategy Example: RDF Preparation and Combustion with Electricity Generation, Ash Disposal in a Monofill, and Landfilling Organic Rejects

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

As implied in "Technology Description," RDF preparation can consist of "shred-and-burn" processing or a more extensive process. The analysis for the integrated strategy covers the more extensive RDF preparation process in which about 20% of the incoming MSW is removed as recyclables and as wet or heavy organic rejects for direct landfilling. The shred-and-burn RDF facilities have energy and emission characteristics quite similar to those of mass burn facilities.

Table 5.6 shows the energy and emissions over a 20-year period from a strategy that includes RDF preparation and combustion. The estimates in the table include energy and emissions for normal collection of MSW, RDF preparation, RDF combustion, land filling of the ash, and landfilling of the unprocessed RDF, as well as the contribution of landfilling to the energy and emissions for the strategy as a whole. Recovery of materials during preparation is part of the RDF production process, and energy effects and emissions from that recycling are included. Credits for savings in energy for actually recycling the separated materials through remanufacture are included as well. The results are given separately for transportation, processing (preparation and combustion of RDF), and disposal (landfilling the ash in a monofill and landfilling the RDF rejects in an MSW landfill). Table 5.7 presents the same data for the landfill strategy.

RDF direct combustion, like mass burning, produces substantial electrical energy, about 3.7 times more energy than is recovered from a landfill. Emissions are similar to those for mass burning, except that the organic rejects increase the quantities of MSW sent to a landfill, where they release methane and leachate.



                                                        Table 5.6

                               ENERGY AND EMISSIONS FOR STRATEGY 4: RDF FOR DIRECT FIRING


                                     Total   Collection   Process   Disposal
Landfill space for residue (assuming
a depth of 50 feet), 10(-5) acres          0.468                               0.468
Solid waste (lb)                            617                                 617
Energy required(million Btu)                2.16       0.079        2.07       0.001
Energy Produced (million Btu)              10.10        0.00        9.75       0.352
Net Energy (million Btu)                    7.94       -0.079       7.67       0.350


Air Emissions
Particulates (lb)                           0.05        0.02       0.004
Carbon Monoxide (lb)                        2.06        0.79        1.27
Hydrocarbons (lb)                           0.08        0.08         NA         0.00
Nitrogen oxides (lb)                        2.64        0.32        2.33
Carbon dioxide (lb)                         1460                    1424         36
Water (lb)                                  970                     940
Methane (lb)                                2.29                     NA         2.29
NMOC (lb)                                   0.12                     NA         0.12
Dioxin/furan {10(-6)lb}(b)                 0.0038                  0.0038
SO(2)                                       1.10                    1.10
HCI                                         0.26                    0.26

Antimony {10(-6)lb}                          ND                      ND
Arsenic{10(-6)lb}                            ND                      ND
Cadmium {10(-6)lb}                           ND                      ND
Chromium {10(-6)lb}                          87                      87
Lead {10(-6)lb}                             320                     320
Mercury {10(-6)lb}                           55                      55
Nickel {10(-6)lb}                            64                      64
Zinc {10(-6)lb}                             170                     170
Total Heavy Metals {10(-6)lb}               696                     696

Effluent
Leachate (gal)                             18.29                               18.29
Leachate (lb)                               152                                 152
Chloride (lb)                               0.82                                0.82
Sodium (lb)                                 0.26                                0.26
Potassium (lb)                              0.17                                0.17
COD (lb)                                    0.02                                0.02
TOC (lb)                                  <0.0002                             <0.0002
Arsenic {10(-3)lb}                          13.8                                13.8
Cadmium {10(-3)lb}                          0.48                                0.48
Chromium {10(-3)lb}                        26.10                               26.10
Copper {10(-3)lb}                           6.88                                6.88
Nickel{10(-3)lb}                           17.30                               17.30
Lead {10(-3)lb}                             7.68                                7.68
Mercury {10(-3)lb}                          0.96                                0.96
Zinc {10(-3)lb}                              NA                                  NA
Total Heavy Metals {10(-6)lb}              73.10                               73.10
AOX (lb)                                   0.173                               0.173


(a) RDF preparation, metal recovery, and RDF combustion.
(b) This is total dioxin/furan as specified by EPA in CFR, 1991a.

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                                                Table 5.7

                       ENERGY AND EMISSIONS FOR STRATEGY 1: LANDFILL WITH GAS RECOVERY


                                 Total   Collection   Process  Disposal

Landfill space (assuming a depth
of 50 ft), 10(-5) acres                2.0                                 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

Effluent
Leachate (gal)                          80                                  80
Leachate (lb)                          667                                 667
Chloride (lb)                          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

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Other Integrated Strategies Described in the Data Base

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