Traditional waste management strategies include reusing materials, recovering materials through recycling, incineration and landfills. In recent years recycling has become the preferred choice of waste disposal for many industries. Each method of waste disposal has its drawbacks. Reusing glass bottles can require more energy than their initial manufacture as they have to be sterilized. Incineration is a source of greenhouse gases and toxic chemicals like dioxins and lead.
Landfill sites are a possible source of toxic chemicals and produce large quantities of methane gas.
They must be managed so that pollutants do not seep into groundwater and should therefore be kept dry, but this slows down the rate of decomposition. Tyres constitute another problem, as their resilience and indestructible nature become distinct disadvantages when it comes to disposal. Tyres are virtually non-degradable and spread noxious fumes when burnt. Western Europe, the US and Japan combined produce around 580 million tyres a year. The ocean has long served as a dumping-ground for human beings' waste, such as dredge spoil and sewage sludge.