Have the students make a poster to raise awareness about the issue of sewage. Split them into groups of 2 or 3 and have them pick three pieces of information that really stood out for them and that they felt other people should be aware of.
Reversing Water Pollution Water Facts: 70% of the Earth is covered by water but only 2% is drinkable, fresh water, one litre of wastewater pollutes about eight litres of freshwater, it's estimated that there is 12,000 km^3 of freshwater worldwide.