Much of the glass collected for recycling purposes in the US is mixed, as in the UK. Both countries have problems finding a suitable outlet for this mixed glass, which can only be used to manufacture new green-glass containers.
It is a problem intensified in the UK by the fact that around 50% of colour-separated glass recycled in the UK is green. Most of this comes from imported wine bottles and cannot be fully used by the UK glass industry, which predominantly produces clear glass, much of which is exported as whisky bottles.
The major solution for the UK is to export much of its excess mixed and green glass to be used in the production of new green-glass containers by European manufacturers. Countries such as Spain and Portugal have traditionally been a core market for this exported UK recycled glass. The amount of glass sent to container manufacturers abroad has doubled in recent years. In 2004, the Department for Environment, Food and Rural Affairs data shows exports at 165,000 tonnes.
"Exports of mixed and green cullet took place from 2002 to 2004," says Paul J Smith, manager of global sourcing cullet at Owens-Illinois. "But international ocean freight rates make this unprofitable at this time." However, he concedes that it could commence again in the future.
"Freight rates are the main driver," he says.
The US has stepped up its glass recycling commitments in recent years, with the Glass Manufacturing Industry Council's (GMIC) creation in December 2002 of a dedicated recycling division. The aim of the division is to find new uses and markets for recycled glass. It has three working groups: one to find the critical cost points in the glass container recycling system; one to look at establishing a standard grading system for cullet; and one to find different uses for recycled glass.
The percentage of glass recovered varies from state to state. In California, for example, overall container recovery rates, including glass, plastic and cans, hit 59% in 2004. But overall the picture is more depressing with poor performances in Illinois and New Jersey.
"We are seeing a large increase in mixed-colour glass," says Smith. "This is largely due to the increase in single-stream recycling." He adds that the US is so large and demands are so varied that matching up demand for cullet with supplies can prove difficult.
According to the GMIC, there is a steady move in the US recycling industry towards commingled single stream handling of all recyclable materials, and this often turns glass into a contaminant instead of a clean, reusable material.
Container production is far from the only use for mixed or green glass. UK recycled glass that is not used in container production is used in aggregates, shot blasting, fibre glass production and in a wide range of decorative products.
Ongoing work by the Waste and Resources Action Programme (WRAP) may also bring forward uses in bricks, water filters and other higher value uses.
Preliminary 2004 figures show that 34% of recycled glass went to such alternative industries, up from 30% in 2003. However, if the UK is to meet its 2008 EU recycling targ