Question

the wastewater from toilets, or ______, may contain high levels of pathogens and must be disinfected. black sewage blackwater gray sewage graywater

Explanation:

In the context of wastewater, blackwater specifically refers to wastewater from toilets (containing fecal matter and urine), which has high pathogen levels and needs disinfection. Graywater is from sinks, showers, etc., and "black sewage" and "gray sewage" are not standard terms for toilet wastewater. So the correct term is blackwater.

Answer:

blackwater