Which substance is typically used to increase the pH of wastewater?

Lime is commonly used to increase the pH of wastewater due to its calcium content and effectiveness as a strong alkaline substance. When lime (calcium hydroxide or calcium oxide) is added to wastewater, it reacts with water to form hydroxide ions, which raise the pH level. This process is essential for neutralizing acidic conditions and can also help in the precipitation of heavy metals as hydroxides, thereby facilitating their removal from the wastewater.

Other substances listed serve different purposes. Acetic acid, for instance, is an acid and would lower pH, thus it’s not suitable for raising it. Sodium hypochlorite is primarily used as a disinfectant and oxidizing agent rather than for pH adjustment. Potassium chloride is used in various applications, including as a salt substitute or for fertilizer, but it does not have an impact on pH adjustment. Therefore, lime stands out as the appropriate choice for increasing pH in wastewater treatment processes.