The study looked at how pre-sedimentation affects the amount of alum needed to treat water from a lake. By testing different doses of alum at different pH levels, the researchers found that pre-sedimentation can help reduce the amount of alum needed for water treatment. They discovered that using pre-sedimentation can lead to up to 98.67% removal of water turbidity. This means that by adding alum after pre-sedimentation, the water can be cleaned more efficiently, saving money and resources in the water treatment process.