What are the two products formed when sewage passes through a sedimentation tank?
Grit that settles out, and screenings that float on the surface
Methane gas that is burned, and a residue used as a fertiliser
Sewage sludge that settles out, and effluent that remains above it
Clean water that can be drunk, and a sludge that must be burned
40 exam-style questions on AQA GCSE Chemistry 10.1 Using the Earth's resources and obtaining potable water, covering 10.1.1 Using the Earth's resources and sustainable development, 10.1.2 Potable water, 10.1.3 Waste water treatment, and 10.1.4 Alternative methods of extracting metals. Each one has a worked solution and a mark scheme showing where the marks go.