Wastewater New York State Practice Exam

What is the stable inorganic form of phosphorus commonly found in waste streams?

1. Polyphosphate

2. Metaphosphate

3. Orthophosphate

4. Diphosphate

The correct answer is: Orthophosphate

The stable inorganic form of phosphorus commonly found in waste streams is orthophosphate. This form is the most basic and readily available type of phosphorus, consisting of one phosphorus atom bonded to four oxygen atoms. Orthophosphate is highly soluble in water, making it the predominant form of phosphorus in natural waters and wastewater environments. In sewage and industrial waste streams, orthophosphate is essential to track because it can contribute to nutrient loading in aquatic ecosystems, leading to problems such as algal blooms. Monitoring orthophosphate levels helps in understanding and managing these nutrient dynamics effectively. Polyphosphate and metaphosphate are forms of phosphorus that consist of multiple phosphate groups and can be more complex in nature. Diphosphate, which also refers to a type of polyphosphate, is typically less prevalent and can be unstable in waste streams. Therefore, orthophosphate stands out as the key stable inorganic form in this context.