If waste cannot be processed for recovery or as a source of energy and cannot be treated for discharge to the surface water or air, it must be disposed off on land, this is known as sanitary land filling. The landfill site should be so designed as to reduce environmental and health risks.

Thus the method essentially consists of laying the material systematically followed by its compaction to smallest practical volume with least exposed area and then covering it with soil. As it is compacted, further decrease in volume will not be very large. As the exposed surface area will be the smallest the amount of soil cover needed will be small which is an important consideration, especially when the soil cover has to be brought from outside.

Covering of the waste with soil or other inorganic material makes it inaccessible to flies and rodents and the heat released during decomposition is conserved, increasing the chances of destruction of fly larva and pathogenic organisms.

The major aspects that must be considered for sanitary landfill are as follows:

1. Type and volume of hazardous and non-hazardous waste to be landfilled
2. Life expectancy of landfill during its active operating period
3. Topography and soil characteristics at the site in its vicinity
4. Climatic conditions throughout the year
5. Surface water and ground water in the vicinity
6. Collection and treatment of surface run off
7. Selection of leachate collection and treatment systems
8. Effect on human health and the environment
9. Selection of venting systems for gaseous products

Types of Sanitary Landfill

Sanitary landfilling can be practised for all types of site conditions. To suit different site conditions, the basic process is modified in three distinct ways

1. trench method
2. area method
3. ramp method