Dementor's kiss

just wondering about this. Once a dementor sucks out a soul, where does it go?

Arrow Into it's tummy - does it consume it like food?
Arrow Into a storage facility to keep for an energy source?

If the souls are still viable, can they ever be returned to their owners? We saw in PoA that Harry's patronus was able to drive the dementor away from Sirius before he could be completely "kissed", and some went back in. Could this be significant in any way?

Ha ha, you pinched this directly from the other forum... I know cos I wrote it!!!

Most of my threads we duplicates between Phoenix & a hpfans one I go on. Hmm, I'm not sure how to answer myself

Obviously we know now that there was no significance in the kiss, but I've come to the conclusion that it was always a source of energy for them. Any other ideas?