Water Treatment Plant Operator Practice Exam 2026 – The Comprehensive Guide to Master Your Certification!

Alum is a widely used coagulant in water treatment processes because it effectively facilitates the aggregation of suspended particles in water, leading to their removal. It acts by neutralizing the negative charges on particles, allowing them to clump together and settle at the bottom during sedimentation. This mechanism enhances the clarity and quality of water, making it a common choice in both municipal water treatment and wastewater treatment facilities.

In contrast to other substances mentioned, alum is specifically recognized for its efficiency and reliability in coagulation processes. It forms aluminum hydroxide when dissolved, which entraps impurities and provides a solid mass that can be easily removed. Other options like alkaline phosphates, calcium chloride, and sodium sulfate may serve different purposes in water chemistry but do not fulfill the role of enhancing coagulation effectively as alum does.