10.3.1 Estimation of the required land area
As an example, think of a town with a population of 25,000 people that produces around 4000 metric tons of waste a year (residential, commercial and industrial). The town intends to construct a controlled landfill that will last for five years.
The first stage is to estimate the volume of space that this waste will occupy. From previous experience, it is known that one cubic metre (1 m3) of waste weighs about 600 kg when landfilled; in other words the density of waste is 600 kg per m3. So one year’s worth of waste (4,000,000 kg) will occupy:
Therefore five years’ waste will need m3.
But we also need to allow for the soil that is used to cover the waste. Again, from experience, it is known that this will add about 10% to the space required. In this case we will need:
We now need to calculate the land area. If we assume that the depth of the waste and soil cover in the site will be 3 m, the site area required will be:
Although this is the requirement for the land used for disposal, additional land is required to give space for vehicles to move, for the cover soil to be stored and for an amenity building. From Section 10.2.4, this will account for a further 15%, so the site area becomes:
If the site were rectangular, a space of 100 m by 140 m would be suitable.
10.3 Planning controlled landfills for small and medium-sized towns
10.3.2 Finding a suitable location