This question is about water - AQA - GCSE Chemistry - Question 2 - 2020 - Paper 2

One process this country could use is reverse osmosis, which is a method that allows desalination by filtering seawater through a semi-permeable membrane. This process removes impurities and provides a viable source of potable water despite the country’s low rainfall.

Liquid effluent → Anaerobic digestion Solid sewage sludge → Aerobic biological treatment

To calculate the percentage of processed solid sewage sludge burned in 2010:

$ext{Percentage} = \left( \frac{\text{mass burned}}{\text{total mass}} \right) \times 100$

Substituting the values:

$\text{Percentage} = \left( \frac{260}{1413} \right) \times 100 = 18.4\%$

Thus, the percentage of processed solid sewage sludge that was burned in 2010 is 18.4%.

One reason for the increase in the total mass of processed solid sewage sludge between 1992 and 2010 is the growing population, which leads to more waste generation, thereby producing a larger amount of sewage sludge.

1. Increased demand for food due to the rising population leads to greater farming activity, which utilizes more organic fertilisers.
2. More awareness of the environmental benefits of recycling waste into fertilisers may have encouraged the use of processed solid sewage sludge in agriculture.