Analysis of environmental impact reduction effect of applying high-speed flash mixer in sewage sludge dewatering process

초록

As the urgency of achieving carbon neutrality becomes more pronounced, the expansion of eco-friendly sewage treatment processes is essential. Notably, the use of high-speed flash mixers in sludge dewatering, which helps reduce sludge water content and water contamination levels in sewage treatment, is gaining traction as an effective technology. Although several pilot projects have demonstrated the effectiveness of such an approach, the broader environmental impacts of such a process have not been thoroughly investigated. This study addresses this gap by performing a comprehensive life cycle assessment (LCA) to compare the environmental impacts of the current sewage sludge dewatering process (current process) with a process enhanced by high-speed flash mixers (improved process). The results show substantial reductions in several environmental indicators: ozone depletion potential (ODP) and photochemical ozone creation potentials (POCP) decreased by 8.81E-07 kg CFC-11-eq. (▼22.0%) and 3.97E-03 kg C2H4-eq. (▼13.4%), respectively. Additionally, the eutrophication potential (EP), abiotic depletion potential (ADP), acidification potential (AP), and global warming potential (GWP) decreased by 2.64E-02 kg PO43—eq. (▼4.1%), 5.13E-01 kg Sb-eq. (▼4.0%), 1.37E-01 kg SO2-eq. (▼4.0%), and 8.05E+01 kg CO2-eq. (▼4.0%), respectively. However, this study did not account for the environmental impact of treating dried sludge after dewatering because of data limitations. Nonetheless, the study also highlights the significant environmental impact of using polymer coagulants during dewatering and suggests that improving the reaction rate between the sludge and polymer coagulants can enhance environmental performance. This includes reducing polymer use and developing eco-friendly alternatives that improve the environmental sustainability of sludge dewatering processes. The findings emphasize the importance of policy support and management within related industries and advocate for ongoing research and development to promote eco-friendly practices in sewage treatment to support carbon neutrality objectives. © 2024, Korea Society of Waste Management. All rights reserved.

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