What is the primary purpose of using alum in wastewater treatment?

The primary purpose of using alum in wastewater treatment is to clarify water. Alum, which is a coagulant, plays a crucial role in the removal of suspended solids and turbidity from water. When alum is added to wastewater, it reacts with the suspended particles, causing them to clump together into larger aggregates known as flocs. These flocs can then be easily separated from the water during subsequent sedimentation or filtration processes.

Clarification is an essential step in wastewater treatment because it helps improve the overall quality of the effluent before it is discharged or further treated. By effectively removing suspended solids, alum aids in reducing the turbidity of the water, making it clearer and more suitable for discharge into natural bodies of water or for reuse. This is particularly important for meeting environmental regulations and protecting aquatic ecosystems.

The other options, while related to wastewater treatment processes, do not capture the primary reason for using alum as accurately. Enhancing biological processes or increasing flow may be part of the broader treatment strategy but are not the main function of alum in this context.