Which of the following is NOT a common technology used for treating turbidity?

The correct choice for this question is based on understanding the specific functions and applications of each technology mentioned in the context of treating turbidity in water.

Chemical treatments involve the use of coagulants or flocculants to aggregate fine particles suspended in the water, which can significantly reduce turbidity. Dewatering tanks are designed to remove excess water from sludges or sediments, which can also help in managing turbidity by allowing solids to settle out. Sediment traps capture sediments and particulate matter from flowing water, thereby decreasing turbidity levels in downstream water bodies.

Sand filters, while effective in filtration processes, are primarily utilized for the removal of larger particles and sediment rather than specifically targeting turbidity. They work best for suspended solids that are larger than the pore size of the sand. Thus, while sand filters can contribute to reducing some turbidity levels, they are not primarily recognized as a common treatment technology specifically designed to address turbidity issues in water treatment contexts. Instead, they are more often associated with general filtration processes, which differentiates them from the other technologies listed.