Thanks, everyone. I like the evaporation idea a lot, but in Ireland I would be waiting a long time for a dry day, I suppose I wonder what would they say at the collection centre (only twice a year in my locality) when I deliver a thick crusted orangey sludge... I guess I will have to try and see. I will also see if Louise at John Gunns in Wexford St might be willing to take sludge etc if I promise to buy more film from her.
I was very attracted to the idea of JNanian's simple silver recovery technique, but I never quite found anyone interested in taking the silver-rich sludge off my hands in Ireland...
When I lived in London, I was just told to put everything in my regular home drain. The local authority (borough of Ealing) proudly told me that the facilities of Thames Water would easily cope with non-commercial quantity of photo chemicals including spent Selenium toner. I guess septic tank is a very different story.
Thanks - and if anyone in Wicklow or Dublin has found another route, please let me know. Otherwise I will be evaporating.