Complete the summary below.
Write NO MORE THAN TWO WORDS for each answer.

Green sand

The use of crushed green glass (AFM) may have two significant impacts: it may help to save a diminishing [1] while at the same time solving a major problem for the [2] in the UK. However, according to Howard Dryden, only glass from bottles that have been used for [3] can be used in the production process. AFM is more effective than [4] as a water filter, and also has other uses.