should be constructed just off the fill area. 
However, with proper engineering considera- 
tions, even heavy buildings may be con- 
structed on completed fills. 
10. Unsightliness, health hazards, and nui- 
sances of open dumps are eliminated. 
11. Sanitary landfills can be established 
quickly. 
12. Several disposal sites may be used simulta- 
neously at a relatively small additional cost. 
Disadvantages of Sanitary Landfills 
1. Suitable land at reasonable cost within 
economical hauling distance may not be 
readily available. 
2. Improper construction may permit surface 
cracking and uneven settling, resulting in 
difficulty for trucks traveling on the surface 
in bad weather and giving an untidy 
appearance. 
3. A landfill may settle from 10 to 25 percent 
depending on the degree of compaction, 
during the first 2 years, thereby requiring 
regrading and maintenance. 
4. Fills generally present some difficulties for 
subsequent heavy construction. 
5. If not properly located, seepage from fills 
into streams may increase stream pollution 
but may not show up for some time. This 
pollution is very difficult to alleviate. 
6. Excavation in old fill areas may be objec- 
tionable because of obnoxious odors. 
7. Problems in constructing buildings on 
former landfills are created, since methane, 
an explosive gas, is generated as decompo- 
sition proceeds. 
8. Relatively large areas of land are required. 
9. Decomposition of refuse in fills is slow in 
many areas. 
10. An adequate supply of good earth cover may 
not be readily accessible. 
11. The idea of the sanitary landfill often is 
difficult to sell because people think a 
sanitary landfill and a dump are synonymous. 
INCINERATION 
Incineration offers an excellent means of sani- 
tary refuse disposal. The term incineration, as 
applied to the disposal of municipal waste, means 
the burning to ashes of all combustible portions of 
community refuse. 
The newer incineration plants are architectur- 
ally pleasing, will handle mixed refuse containing 
both garbage and rubbish, and can be maintained 
in a clean and sanitary condition. Careful attention 
to design and operation has considerably reduced 
the atmospheric pollution that formerly resulted 
from incinerator operation. 
The size of an incineration plant and its loca- 
tion within the town or city should be given careful 
consideration. Table 2 shows the suggested ca- 
pacity of the incinerator according to the size of 
the population to be served. For purposes of 
economy, it should be located as near as possible 
to the center of the community. This will result in 
short haulage distances, more frequent round trips, 
and high collection vehicle productivity. 
Incinerators should be designed to operate 
satisfactorily at all seasons of the year. Garbage 
that has received proper pre-storage handling and 
good storage at homes and businesses frequently 
contains about 70 percent moisture by weight. 
During the summer when fresh fruits and vegeta- 
bles are abundant this moisture content may be 
much higher. Rubbish, which consists mostly of 
combustible materials, has a lower moisture 
content. It is this rubbish in refuse that makes 
incineration practical by providing free fuel to 
reduce the refuse to a sanitary, easily handled, 
nuisance-free residue. 
The elimination of the moisture content is the 
first of the three basic stages in the incineration 
process. Before refuse can be burned it must be 
dry, so an efficient incineration plant must provide 
a way to eliminate the moisture from raw refuse. 
This is accomplished by having the “green” 
refuse placed at the back of the burning furnace 
or in a separate chamber, and from there it is 
moved to the actual burning area by mechanically 
operated grates or by hand stoking. 
The actual burning of the combustible material , 
converting it into gases and leaving an inert 
residue or ash. is the second stage. A pre-heater 
may contribute greatly to plant efficiency by rais- 
ing the temperature of the forced draft before its 
introduction into the furnace. Waste heat is fre- 
quently used for this purpose. This heated air for 
the forced draft helps the incinerator operate 
efficiently, particularly when the refuse contains 
an excessive amount of moisture. Gas or oil 
burners are sometimes included to provide the heat 
necessary to evaporate excessive moisture or to 
bring temperatures more quickly to the most effi- 
24 
