654 MANAGEMENT OF SOLID WASTE
TABLE 13
Solid waste management methods
Type Present usage Relative cost Items disposed of Principal benefits
Sanitary landfill Most used (80%)
decreasing^9
Lowb All except hazardous
materials
Low initial cost,
takes all items
may reclaim land
Central incineration Increasing
second largest
method (4%)
High All burnable except
special items and
over-sized items
Reduces volume,
clean product can
produce by-
product items
Open burning Illegal Low Construction
wastes, leaves,
agricultural waste
Compaction, high
pressure
Two plants in
operation
Medium-high All except
hazardous
materials
Produces dense,
essentially inert
blocks for fill
Composting Very few Medium-high Organic only.
No tires,
large pieces
Provides soil
conditioner
Garbage grinding Large number home
units
High Organic only Reduces domestic
collections
Dumping Not legal Lowest Non-putrescibles
Recycling Only for selected
materials and
areas, increasing
High Selected.
Depends
on process
Reduces quantity
for ultimate
disposal
a Many landfills are not sanitary but are included in this classification.
b Low under $10/ton; Medium $10 to $30/ton; High $30 ton.
1
2
3
4
5
6
7 8
9
10
12
11
13
1) — feed section
2) — feed chute
3) — grate
4) — furnace
5) — residue hopper
6) — secondary combustion chamber and
downpass flue volume
7) — final burning and settling chamber volume
8) — high-pressure opposed spray curtain
9) — fly-ash sluiceways
10) — sequential cyclone collectors
11) — induced-draft fan
12) — bypass flue
13) — provision for added filters or
precipitators
FIGURE 3 Large incinerator schematic.
beyond the scope of this work and the reader is referred to an
excellent work by Richard C. Corey.^22
Incineration in the past has received a bad reputation
because of poor control of gaseous effluents and sloppy han-
dling of solid and liquid effluents. With proper design and
operation an incinerator can meet or exceed requirements
on all effluent discharges. A modern central incinerator is
a more complex operation than a large commercial steam
boiler. It therefore requires skilled operating, maintenance
and supervisory personnel to ensure efficient operation.
At the present time control of particulate matter in the
effluent gas is the most critical problem in incinerator design
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