Development of substance flow based Life Cycle Assessment tool for sewage sludge treatment and disposal

Life Cycle Assessment (LCA) is a method to quantify environmental impacts of products or systems. It is often done by correlating material and energy demands with certain input characteristics. An attempt was made to evaluate the robustness of the substance flow based LCA for wastewater and sludge treatment processes.

Operational data of a conventional wastewater treatment plant over 12 years was collected. A cluster analysis was conducted to determine the relatedness of each input and output characteristic at the whole plant level. The results indicate that the output from the wastewater and sludge treatment processes correlate sufficiently with the solids content of wastewater influent, while energy use correlates with the total input volume.

However, the correlations appeared to be stronger when individual treatment processes were separately analysed.