How much waste needs to go to landfill?
When talking about waste and landfill there are a few basic definitions that need to be understood to make sense of it all. The first is to understand the term arisings. Included in the figures for arisings is waste that's immediately reused or relocated on site, such as the product of dredging a river or canal which is deposited on the bank, unsaleable mineral and mining waste that is dumped elsewhere within the mine or quarry, and construction and demolition waste that is spread on site or crushed and reused elsewhere. Waste arisings from industrial processes frequently have a residual value and are re-sold or reused, and other industrial and commercial waste can be profitably recycled. Thus of the estimated 335 million tonnes of waste arising in the UK each year, only a small fraction needs to be disposed of.
Secondly, not all waste that needs to be disposed of can be sent to landfill. Medical, clinical and biohazardous waste needs to be incinerated and toxic and radioactive waste similarly needs special treatment. However, both these categories are so small in overall tonnage terms that they can be ignored. Of the remaining waste for disposal, much will be inert, such as demolition rubble, and can be disposed of near to people and close to watercourses without risk. The remainder of household, commercial and industrial waste that may rot or that contains pollutants or products of decomposition that fall below hazardous can be disposed of in dry landfill. So how much of that 335 million tonnes needs to go to landfill altogether?
From DEFRA's published figures here, here and here, the annual totals are:
|Waste to landfill||UK Million Tonnes|
|Household waste (2006)||22.46|
|Construction and demolition (2005)||28.00|
|Commercial and Industrial (2009)||11.30|
In fact, the household figure is too high; it's actually the figure for what's termed municipal waste and includes both household waste and a proportion of commercial and industrial waste where councils collect and dispose of this as well, so there's some double-counting. But no matter, let's stick with the higher total.
Where does the landfill capacity come from?
Landfill sites come mainly from the activities of quarrying and minerals extraction - holes in the ground. Generally, hard-rock and opencast coal sites will tend to be dry and suitable for all types of non-hazardous waste whilst sand and gravel workings are frequently close to the water table and will be mainly suitable only for inert waste. The following figures are for the annual quantities of products sold, i.e. the quantity of space created by materials leaving the quarry gate. Unsold excavated material that is redistributed elsewhere in the workings is not included.
|UK Million Tonnes||Density tonnes/m3||UK Million Cubic Metres|
|Land-won sand and gravel||66.64||1.65||40.39|
|Crushed Rock (note 1)||128.00||2.60||49.23|
|Clay and Shale||6.47||2.00||3.23|
|Limestone & Chalk||23.62||2.55||9.26|
|1. Assume 50% limestone, 35% igneous rock, 15% gravel|
|Source: British Geological Survey, UK Minerals Yearbook 2009|
|Excludes Marine dredged aggregate, Peat, Rock Salt|
You will have noticed I've converted tonnage to capacity; this is important in the next section, in which we compare the capacity of annual space created against the capacity of waste requiring landfill disposal. But you will see that we take some 246 million tonnes of stuff out of holes in the ground each year and need to put 62 million tonnes of stuff back in.
Is landfill in the UK running out?
This is where we need to watch our figures. Firstly, we have lots of empty holes in the ground left over from two centuries of industry and development. So total capacity is the sum of the existing capacity plus the new capacity created each year. Then there's a big difference between licensed existing landfill capacity and actual existing landfill capacity; not all quarries and mineral workings are licensed to receive waste. And then there's the frustration that England and Wales, Scotland and Northern Ireland all report their licensed capacity separately, and whilst England and Wales report in terms of volume, Scotland reports in tonnage terms.
The mass density of compacted household waste will vary widely, but from a number of studies a density of around 0.77 tonnes / cubic metre can be assumed. Construction and demolition waste will be denser, around 1.0 tonnes / cubic metre.
First, existing licensed capacity is as follows;
|Licenced existing landfill capacity|
|Million tonnes||Conversion factor||Million Cubic Metres|
|England and Wales (2006)||n/a||n/a||693.73|
|Northern Ireland (2005)||1||0.85||0.85|
Now converting our annual waste streams to volume;
|Waste to landfill||UK Million Tonnes||Conversion factor||Million Cubic Metres|
|Household waste (2006)||22.46||0.77||29.17|
|Construction and demolition (2005)||28.00||1||28|
|Commercial and Industrial (2009)||11.30||0.77||14.68|
1. The UK has some 819 million cubic metres of licensed landfill capacity, sufficient for over 11 years of waste at current levels
2. The UK's potential landfill capacity is increasing at the rate of 114 million cubic metres a year, a surplus of some 42 million cubic metres a year over and above our annual landfill waste disposal needs
3. There is no shortage of landfill in the UK.
Given the above, if you fancy fisking silly, poorly researched scare stories such as this one in the Guardian, be my guest. I can't be arsed.