Chromogenic refers to photographic processes that work by forming a conventional silver image and then replacing it with a dye image. (Wikipedia).
The most common chromogenic processes are - C-41 for color (and chromogenic black-and-white) negative film. - RA-4 for color negative paper (see Type C print). - E-6 for slide film.
The main hazardous waste product of chromogenic processing consists of silver compounds dissolved in the used fixer. A history of improper handling of waste fixer has led to environmental contamination (e.g. untreated waste fixer into the sanitary sewers may led to high levels of dissolved silver in public waters).
Possible solution: process the waste to recover the dissolved silver in metallic form, and to allow safe disposal of the remaining substance.
Liquid C41 kit: Two liters will process approximately sixteen rolls of 35mm x 36 exp. film with reuse.