Energy production from small WWTP clusters (D2.5)

Bodø Municipality is involved in the EU project B-WaterSmart as one of the living labs. The goal of each living lab is to develop water-smart solutions in collaboration with private businesses and research institutions. This report focuses on improving resource recovery from wastewater in an efficient way given the small scale and decentralized wastewater treatment plant structure in Bodø with six small wastewater treatment plants, which presents a challenge concerning cost-efficient biogas production from sludge according to conventional wisdom. Six alternatives (Alternatives 0-5) were assessed to evaluate the potential of biogas production from different sludge and solid waste streams from Bodø and the surrounding area in Salten. Overall, the results indicate that Alternative 4 will be the preferred solution. This is mainly due to a combination of having valuable products (biogas, bio-oil and biochar) and saving volume and presumably investment costs by using an UASB instead of an anaerobic digester. This is what one would expect based on the comparisons of volume and footprint as well as the energy balance in the technical assessment. However, due to limited data availability, one should take this only as a preliminary conclusion that should be verified considering the uncertainties in the value chain for bio-oil and biochar and the level of accuracy in the technical evaluation.