13) When developing film, how do you dispose of fixer as opposed to developer? A) Fixer is poured down the drain while developer can be reused.
B) Developer is poured down the drain while fixer can be reused.
C) Both developer and fixer can be poured down the drain.
D) I don't know.

B) Developer is poured down the drain while fixer can be reduced

Explanation:

The effluents produced during photographic processing includes, wash water, bleach, fixer, and developer

The developer is an alkaline solution, with a pH of approximately 10.0, while the pH of the fixer is about 4.3, it is therefore, acidic

The rate of discharge of the developer to the fixer is 2 to 1, and the exhausted developer, fixer and process effluents combined are neutral and can be handle by the the treatment works and the drain pipes

Fixer which remain clear can be reused for more than a day, while the spent basic Developer and the acidic Spent Stop Bath can be combined to form a neutral solution, having a pH of approximately 7, which make them less hazardous to be disposed off down the sink into the drain

Therefore, developer is poured down the drain while fixer can be reused