Wastewater Treatment

Example Problem $2$

Water treatment often includes two disinfection steps; with the first disinfection step ensuring that water exiting the plant meets the standards for microbiological quality, while the second disinfection step ensures that there will be enough residual across the entire distribution network. Is there a similar requirement for wastewater treatment? Why or why not? And does the answer depend on the type of urban water cycle? Please keep your answer brief, a maximum of four sentences is recommended.

$[6]$