Which pH reading indicates acidic wastewater?

A pH reading of 3 indicates acidic wastewater because the pH scale ranges from 0 to 14, with values below 7 being categorized as acidic. Specifically, a pH of 3 is significantly lower than the neutral point of 7, indicating a higher concentration of hydrogen ions, which is characteristic of acidic substances. In wastewater management and environmental science, understanding pH levels is crucial, as acidic wastewater can lead to detrimental effects on water quality, infrastructure, and aquatic life.

In contrast, readings of 12 and 9 indicate alkaline conditions, with 12 being strongly alkaline. A pH reading of 7 indicates neutrality, meaning the water is neither acidic nor alkaline, which does not apply in this context when determining acidic conditions.