(291b) Sustainable Production of Polyhydroxyalkanoates from Foul Condensates by Pulp Mill Waste Activated Sludge

Biological treatment of pulp mill effluents from the kraft foul condensate collection system offers an opportunity to create an additional product from the recovered carbon while reducing the environmental impact of pulp production. Foul condensates, methanol-rich pulp mill effluents, are conventionally treated by incineration, which represents a loss of carbon from the mill and additionally introduces airborne pollutants such as NOx, SOx and particulates. Biological treatment offers the potential to remove the methanol from foul condensates while producing renewable value-added products such as polyhydroxyalkanoates (PHAs). Polyhydroxyalkanoates are microbially-synthesized intracellular polyesters that serve as carbon and energy storage reservoirs. In this work, laboratory scale sequencing biological reactors (SBRs) were used with inocula originating from the mill's wastewater treatment system to produce PHAs from methanol and other COD present in foul condensates. Environmental conditions that affect polymer storage include hydraulic residence time (HRT), solids retention time (SRT), food to microorganism ratio (F:M) and carbon to nitrogen ratio (C:N). Experiments to date have focused on optimizing the C:N ratio, and will subsequently explore the impacts of HRT, SRT, and F:M at a fixed C:N. The results will be empirically modeled using response surface methodology. We will present an assessment of the effects of HRT, SRT, and F:M on the yield of PHA in the biosolids.