A carbon copy of an Albany, NY water treatment facility, this may be the last of its kind, though not functioning. With 20 silos and underground vaults that are sand-filled to treat water. Algae was grown purposefully to purify the water and the sand filtered out sediment to be pumped out to to the households and businesses of DC until it was replaced by chemical and mechanical treatment by the US Engineer Corp.
A fascinating space whose future is still unknown is a great source of fascination with what was, an interest in what is, and an inspiration for what could be!
Check out the PBS mini-documentary here.