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:

four comma 000 comma 000 divided by 600 equals 6667 m3

Therefore five years’ waste will need reverse solidus six 667 multiplication five equals 33 comma 333 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:

33 comma 333 multiplication 110 divided by 100 equals 36 comma 667 m3

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:

36 comma 667 divided by three equals 12 comma 222 m2

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:

12 comma 222 multiplication 115 divided by 100 equals 14 comma 055 m2

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