$\begin{array}{1 1} \text{a. Have high amounts of suspended solids and dissolved salts} \\ \text{b. Is processed by aerobic and then by anaerobic bacteria in the secondary treatment in sewage treatment plants.} \\ \text{c. Has a high BOD as it contains both aerobic and anaerobic bacteria.} \\ \text{d. When treated in sewage treatment plants does not really require aeration step as the sewage contains adequate oxygen.} \end{array}$
