Effects of gas phase components on phosphorus removal from an iron-rich digested sludge

Abstract

Gas phase effects on key elements in digested sludge were investigated, with focus on phosphorus and its removal. Simplified models in the form of predominance diagrams were used to explore Eh-pH regions that are favourable to the precipitation of struvite or vivianite. Experiments performed included subjecting the digestate to conditions low in carbon dioxide and/or oxygen. Effects on key elements in the liquid phase of the digestate were in line with expectations and the simplified models.