CE Delft has assessed the climate impact of the Spodofos process, a new technology that enables the recovery of phosphorus from sewage sludge ash. Recovering phosphorus from waste streams is important, as it is a scarce resource that is essential for agriculture. In addition to white phosphorus, the Spodofos process also produces slags and ferrophosphorus. These by-products can also be usefully applied (after potential further processing).
This life cycle assessment (LCA) was carried out for ThermusP, the developer of Spodofos.
The analysis shows that processing one tonne of sludge ash with Spodofos results in a climate impact of approximately -1.4 tonnes of CO2-equivalent. The negative value indicates that, on balance, greenhouse gas emissions are avoided. This is because the products from the Spodofos process replace conventional products with a higher climate impact. The greatest benefit comes from avoiding the conventional production of white phosphorus. Moreover, all products from the Spodofos process have a lower climate impact than the conventional products they can replace.
The CE Delft report in which the analysis is described is included in a larger report by STOWA: “Spodofos: White Phosphorus Production from Sewage Sludge Ash. Quality and Applications of the Products and Update of Feasibility and LCA.”