Massachusetts Wastewater Practice Exam

Following coagulation, the next step in physical-chemical treatment is called:

1. Brownian

2. Destabilization

3. Flocculation

4. Precipitation

The correct answer is: Flocculation

The correct answer, flocculation, refers to the process that follows coagulation in physical-chemical treatment of wastewater. During coagulation, chemicals called coagulants are added to the wastewater to destabilize the fine particles and allow them to clump together. This is the first step in the removal of suspended solids. Flocculation comes next, where gentle mixing encourages these destabilized particles to gather into larger aggregates called flocs. This process enhances the efficiency of subsequent treatment stages by increasing the size and settling rate of the solids, making it easier to remove them from the water. Effective flocculation leads to improved overall performance of the treatment system, resulting in clearer effluent. Understanding this sequence is crucial because proper operation depends on the effectiveness of coagulation followed by flocculation. Other options like destabilization and precipitation represent different processes in water treatment, but they don’t directly follow coagulation in this specific context. Destabilization is involved in the initial phase similar to coagulation, while precipitation typically occurs afterward or in different treatment scenarios to remove dissolved contaminants. Therefore, flocculation is the most appropriate step following coagulation in the physical-chemical treatment process.