Water with high amounts of color coagulates better at which pH level?

Water with high amounts of color tends to coagulate better at low pH levels due to the increased effectiveness of coagulants such as aluminum sulfate or ferric chloride, which work optimally in acidic conditions. At low pH, the positive charges on the coagulant particles can more effectively neutralize the negative charges on suspended particles and color compounds, facilitating their aggregation and subsequent removal from the water.

In addition, lower pH levels can decrease the solubility of certain color-causing compounds, making them more amenable to coagulation. This process enhances the formation of larger flocs, which can more easily settle out of the water during the treatment process.

Neutral and high pH levels may not provide the same level of efficiency for coagulants because they may not effectively neutralize the charges or may lead to increased solubility of the color compounds, thus negatively impacting the coagulation process. Therefore, managing the pH of water treatment processes is crucial for optimizing the coagulation of colored waters.