Hidden carbon - a gap in urban water planning

Research Project, 2020

Water planners and life cycle analysts routinely assume that all the carbon entering a city's wastewater system is of biological origin.  Consequently, the emissions of carbon dioxide that arise from the wastewater treatment system are ignored when calculating a carbon footprint.  Unfortunately, there is a little data which indicates this assumption is mistaken, but not enough to say how badly mistaken it is.  This project was funded by a little seed money from Formas to do some preliminary assessment including some "snapshots" of wastewater in Stockholm and Gothenburg.  We were able in this way to confirm our expectations that we would find considerable flows of fossil carbon in Swedish urban wastewater and the sludge produced during treatment.  Now we need to create a larger project to better certainty around the amounts and their consequences for decisions which are being made about sustainable management of wastewater.