How the fate of N, P and C affects the environmental life cycle performance of wastewater and sludge management

This paper discusses the fate of nitrogen, phosphorus and carbon in wastewater and sludge management and argues that the fate of these elements may have a large impact on the life cycle environmental performance of such systems. The effect of changing plant operation to increase N removal and to add also P control, thereby shifting the transfer of the elements between different media, was studied, using data from mass and energy balances and from literature. A sensitivity analysis was also made. It was shown that LCA results are considerably affected by both considered operational changes and by assumptions on the magnitudes of some parameters.