Process for the environmentally friendly purification of photographic wash water from film processing machines and apparatus for carrying out the process

摘要

The present invention relates to a process for the environmentally friendly purification of thiosulphate-containing wash water from film processing machines and an apparatus for carrying out the process. The wash water is passed through an open-pore polyurethane foam containing 60-80% by weight of iron powder having a particle size of 20-200 0m, the contact time with the iron powder being at least 30 s and the pH of the purified wash water not increasing above 7.5.