Valuable product production from wood mill effluents

摘要

Fibreboard production is one of the most important industrial activities in Galicia (Spain).nGreat amounts of wastewater are generated, with properties depending on the type of wood,ntreatment process, final product and water reusing, among others. These effluents arencharacterized by a high chemical oxygen demand (COD), low pH and nutrients limitation.nAerobic and anaerobic processes have been used for their treatment. Presently, bioplasticsnproduction (mainly polyhydroxyalkanoates or PHA) from wastewaters with mixed cultures isnbeing studied. Substrate requirements for these processes are a high organic matter contentnand low nutrient concentration. Therefore, wood mill effluents could be a suitable feedstock.nPHA production from wastewaters is carried out in three steps. First, complex organic matternis converted into volatile fatty acids (VFA) through acidogenic fermentation. Then, VFAnare used as substrate in an aerobic sequencing batch reactor (SBR), in which the enrichementnof PHA producing bacteria from a mixed culture is favoured. Finally, the sludge from the SBRnis fed with a pulse containing high VFA concentrations, resulting in PHA accumulation insidenthe cells. In this work, the possibility of applying this process to wood mill effluents isnproposed. An acidification percentage of 37% and a storage yield (YSTO) of 0.23 Cmmol/Cmmolnwere obtained.