The study compared different chemicals for cleaning polluted water with low temperature and dirtiness. They found that using aluminum sulfate with activated silica works best for cleaning water from Songhuajiang. The best pH for cleaning water is between 6.0 and 7.0. Overall, using ferric chloride is the most effective way to clean polluted water. It's important to choose the right chemicals to remove dirt and organic substances from water to make the cleaning process more efficient.