Environmental Science help?

1.
All of the following are a part of the secondary treatment at a sewage treatment plant EXCEPT
A) Bacteria consume oxygen.
B) Coffee grounds are filtered out.
C) Water is released into the ocean.
D) Chlorine is added
1 c
2 c
3 a
4 d
5 d
6 a
7 b
8 a
9 a
10 b
11 d
12 a
13 c
14 d
15 d
16 a
17 b
18 a
19 c
20 d