Remanence from reclamation of rinse water Anaerobic digestion of remanences from reclamation of rinse water was tested in laboratory scale reactors. A possible reuse of the remanencess is to convert the remanence dyestuff to biogas through co-digestion in municipal wwTP digesters together with municipal sewage sludge. The experimental programme covered four digesters operated in parallel. One digester operated as a reference digester fed with municipal sewage sludge. The three parallel digesters were operated with a mixture of municipal sewage sludge and up to 20% by volume of metal salt dyestuff precipitate, polymer dyestuff precipitate, and membrane filtered dyestuff concentrate, respectively. The results from the experimental work showed that the digesters fed with dyestuff remanences performed with similar COD reduction and gas production as the reference digester fed with sewage sludge alone. Thus no disturbance of the anaerobic digestion could be detected. We also tested for breakdown and possible re-dissolution of dyestuff during the anaerobic