What kind of water quality can be expected from tertiary municipal wastewater treatment?

Tertiary municipal wastewater treatment involves advanced processes that follow primary and secondary treatment stages, designed to further improve water quality. The processes used in tertiary treatment can include filtration, chemical precipitation, nutrient removal, and disinfection. As a result, the level of pollutants, including pathogens, nutrients, and suspended solids, is significantly reduced.

When tertiary treatment achieves high efficiency in removing contaminants, the water can be treated to a quality comparable to drinking water standards, depending on the specific treatment methods applied and local regulations. This quality means that in certain contexts, especially with rigorous testing and additional treatment, tertiary treated water could be suitable for indirect or direct potable reuse.

Therefore, the statement that the quality of tertiary-treated water can be the same as drinking water reflects the potential for high-quality output, especially suitable for various uses such as irrigation, industrial processes, or even replenishing groundwater supplies. However, while it can reach drinking water quality, additional treatment or safety measures may still be required for it to be directly consumed. Thus, the distinction is made that the quality of tertiary-treated water is significantly improved compared to untreated sewage or even water from earlier treatment stages.