Page images
PDF
EPUB

TABLE 18

TOTAL CAPITAL REQUIREMENTS FOR COMPREHENSIVE MATERIALS RECOVERY PROCESS (1,000 TPD Raw Waste Input Capacity)

[blocks in formation]

TABLE 19

ANNUAL OPERATING COSTS FOR COMPREHENSIVE MATERIALS RECOVERY PROCESS (300,000 TPY Raw Waste Input)

[blocks in formation]

The recovered fiber could be upgraded to a bleached grade competitive with groundwood for printing paper. Although the fiber loss would be significant, the economics of upgrading are unknown now. In general, it appears that recovered paper fiber will have limited markets.

The inorganics recovered should find markets more readily than the fiber, within the grade and quality standards of the output materials. The glass on a color-sorted basis would be accepted for recycling; the aluminum is also readily marketable. In the wet pulping operation there is some concern that the smashed condition of the ferrous metals would be a factor in limiting marketability. However, if this is a limit, mechanical shredding

could be applied.

3.2.9 Fuel recovery. One energy recovery approach is the preparation of mixed waste for use as a fuel in an unconverted form. The model for this approach is the Horner and Shifrin process now being operated in St. Louis, where waste is being tested as a supplemental fuel for an electric utility boiler furnace. (The A. M. Kinney approach is similar.) This process uses the organic fraction of waste after removal of the ferrous metals and delivers the prepared fuel to the utility furnace.

The use of existing power plant facilities to burn the fuel gives the fuel recovery approach a decided advantage in capital investment requirements, which are less than any other recovery process for which data were developed. Only landfill has a lower capital requirement. Investment requirements are estimated at $7,577 per daily ton at 1,000 TPD (Table 20). Net operating costs vary from $5.69 per ton at 250 TPD to $1.62 per ton at 2,000 TPD (Table 21).

This process is competitive with landfill at 1,000 TPD and is superior to landfill at 2,000 TPD. In fact, the fuel recovery concept has the most favorable overall economics of any investigated. It is superior to materials recovery and composting at all levels of operation.

From the standpoint of marketability, fuel recovery also looks favorable. However, it is a single-market commodity aimed at public utilities. When looking at utility fuel requirements, refuse would be a supplementary fuel and would likely not be more than 10 to 15 percent of a utility's requirement in any one geographic location. There is also a possibility of use in industrial applications such as cement kilns, where large quantities of relatively low grade fuel may be used.

There are some institutional barriers to acceptance because the introduction of a nonconventional fuel would require the utility to adopt slightly modified operation procedures for a "low Btu value" supplementary fuel. It appears that the inconvenience of interfacing with a utility could

TABLE 20

TOTAL CAPITAL REQUIREMENTS FOR FUEL RECOVERY PROCESS
(1,000 TPD Raw Waste Input Capacity)

[blocks in formation]
[blocks in formation]
« PreviousContinue »