Tennessee Wastewater Operator Practice Exam

What is magnesium ammonium phosphate more commonly known as?

1. Struvite

2. Ammonium sulfate

3. Calcium carbonate

4. Potassium chloride

The correct answer is: Struvite

Magnesium ammonium phosphate is more commonly known as struvite. This compound is formulated when magnesium, ammonium, and phosphate ions react together, forming a crystalline solid that typically precipitates out of solutions in wastewater treatment systems. Struvite often forms in anaerobic digestion contexts, particularly where there is high ammonia concentration and phosphate presence. In the context of wastewater treatment, struvite can be a concern because its formation can lead to scaling in pipes and equipment, thereby causing operational issues. However, it can also be captured and utilized as a slow-release fertilizer, hence presenting both challenges and opportunities in wastewater management. The other choices—ammonium sulfate, calcium carbonate, and potassium chloride—are entirely different compounds and do not share the same chemical structure or formulation with magnesium ammonium phosphate. Each serves distinct purposes in agriculture, civil engineering, and environmental applications, but they are unrelated to the formation and function of struvite in wastewater processes.