| Date | November 2009 | Marks available | 1 | Reference code | 09N.3.sl.TZ0.E4 |
| Level | SL | Paper | 3 | Time zone | TZ0 |
| Command term | Suggest | Question number | E4 | Adapted from | N/A |
Question
Landfill sites are used to dispose of about 90% of the world’s domestic waste, but incineration is being increasingly used in some countries.
Suggest why some biodegradable plastics do not decompose in landfill sites.
High-level and low-level wastes are two types of radioactive waste. Compare the half-lives and the methods of disposal of the two types of waste.
Markscheme
limited supply of oxygen (prevents the bacteria from acting);
Do not accept air.
high-level waste has longer half-life / low-level waste has shorter half-life;
high-level waste is vitrified/made into glass/buried underground/in granite/in deep mines/under water/in steel containers/in cooling ponds / OWTTE;
low-level waste is stored under water/in steel containers/in cooling ponds/filtered/discharged directly into sea / OWTTE;
Accept cooling ponds/steel containers/under water/concrete containers only once.
Examiners report
This was generally well done although few realised that oxygen was needed for the decomposition of the plastics in landfill sites.
This was generally well done although few realised that oxygen was needed for the decomposition of the plastics in landfill sites.
