Encyclopedia of Environmental Science and Engineering, Volume I and II

MANAGEMENT OF SOLID WASTE 655

and operation. A typical modern facility will include either a

wet scrubber or a spray chamber followed by solid separation

in a baghouse filter or electrostatic precipitator. These methods

can achieve up to 99% removal of particulate matter, which

will meet the code requirement of 0.0 pound 0.03 grams per

DSCF particulate in flue gas at 50% excess air in almost all

cases. The costs for this required cleanup are significant and

can be as high as $2000 per daily ton of refuse capacity (see

Air Pollution Control). Odor control is achieved by providing

adequate time (0.5 sec) in the combustion chamber at temper-

atures above 1500°F. As incineration temperatures in modern

units are between 1800 and 2200°F this poses no problem.

Waste heat recovery has been practiced to only a very

limited degree in the United States. Less than 10% of the

incinerators surveyed in 1966 had waste heat recovery facili-

ties. Presently, there are six major resource recovery mass

burning units in the United States and about a dozen are in

the design or construction stage. This is in contrast to the

practice in Europe where waste heat recovery is practiced in

a large number of units. Those US plants that do recovery of

heat incorporate the water wall principle used in furnaces;

in contrast, a few refuse-derived fuel units have been built

modifying existing boilers previously used as suspension

units; again this compares to the European practice where

water wall incinerators are common.

One water-wall incinerator (600T/D) has been in opera-

tion since 1967 at the US Navy Base, Norfolk, Va.^23 Several

reasons have been advanced for the lack of heat recovery

in the United States. These included adverse economics.

In addition corrosion problems and much slagging of the

walls (due apparently to differences in waste composition)

seems to have held back the use of water walls. With new

technology, and a tighter fuel picture, waste heat recovery in

incinerators will become commonplace in the next decade.

In general municipal service, a 1200 per day ton facility in

Montreal went on stream in 1970 and produces 100,000

pounds of steam per hour and a 1600 ton per day facility in

Chicago started up in 1971. Cogeneration facilities that gen-

erate steam and electricity are now being designed.

The investment and operating costs for incinerators

are high and to date have been one of the major deterrents

to wider use. Typical installations of the 600 to 1000 ton

per day range require an investment of $20,000 per ton or

installed daily capacity depending in part on the air pollution

control devices which can account for 20% of the total cost

as well as size. Water-wall installations typically will run

more than refractory lined incinerators; the 1600 ton per day

Northwest Chicago plant cost about $16,000 per ton. Present

costs are about $40–45,000 per installed ton.

Operating costs including amortization of the investment

will vary between $50 and $200 per ton. Actual values for

generated steam have not been published but estimates indicate

TABLE 14

Waste source and disposal methods

Source Methods recently used Methods for future consideration

Municipal Landfill (80%)

Incineration (10%)

Compaction

Composting

Recycle and reclamation

Chemical processing

Industrial Landfill

Incineration

Recycle

Recycle and

reclamation

Chemical processing

Demolition Dump Reclamation

Incineration

Construction Dump

Open burning

Reclamation

Incineration

Sewage Landfill Incinerate

Compost

Chemical processing

Agriculture Landfill (plowback)

Incinerate

Open burning

Dump

Compost

Chemical processing

TABLE 15

U.S. Public health service landfi ll classifi cation

A: Sanitary

Landfill operated without public nuisance or public health hazard;

covered daily and adequately, no deliberate burning practiced.

B: Operated without public nuisance or public health hazard, but

location permits modification of “A” such as burning of certain

types of waste at site, or covering of fill only three times weekly.

C: Operating techniques permit development of public nuisance and

potential health hazards, such as fly breeding, rodent substance,

and odors.

TABLE 16

Sanitary landfi ll—advantages and disadvantages

Advantages

1) Most economical method when land is available.

2) Low initial investment.

3) Complete and final disposal.

4) Short period of time from need to full operation.

5) Flexible daily capacity with same working force.

6) Reclamation of marginal land for recreational and other uses.

7) All types of waste are acceptable.

Disadvantages

1) Lack of close-by suitable land in urban areas may make

uneconomical.

2) Public opposition in, or near, residential areas.

3) Settling after completion means continued maintenance.

4) Public nuisance and health hazard is not properly operated.

5) Products of decomposition, methane and other gases, may create hazard.

6) Require special practices for construction on completed fill.

Source: US Dept. HEWPHS. Pub. No. 1792.

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