Full-Scale Sewage Sludge Reduction Technologies: A Review with a Focus on Energy Consumption

In recent years, increasing attention has been paid to the problem of sewage sludge management and the relevant energy consumption, which represent the main cost items in wastewater treatment plants. Therefore, implementation of technologies that can reduce sludge production and ensure a positive impact on the energy of the entire sewage treatment plant has gained considerable importance in the scientific and technical community. The objective of this study was thus to screen full-scale sludge reduction technologies integrated into both the water line and the sludge line of a municipal sewage treatment plant with a sustainable impact on the overall balance of the plant. The results showed that, within the water line, ultrasound in the recirculation line of the activated sludge allowed for greater reductions in sludge production than the Cannibal and UTN systems, despite the higher energy consumption. CAMBI (TM), BioThelys (TM), Exelys (TM) and TurboTec((R)) enabled the greatest reductions in sludge production among the technologies integrated into the sludge line, and although they required a large amount of energy, this was partially offset by energy recovery in terms of additional biogas production.

Automated summary

In recent years, there has been increasing attention on sewage sludge management and the associated energy consumption, which are major cost factors in wastewater treatment plants. Therefore, it is important to implement technologies that can reduce sludge production and have a positive impact on the overall energy balance of the sewage treatment plant. This study aimed to evaluate full-scale sludge reduction technologies integrated into both the water and sludge lines of a municipal sewage treatment plant. The results showed that ultrasound in the water line and CAMBI (TM), BioThelys (TM), Exelys (TM), and TurboTec((R)) in the sludge line were the most effective technologies in reducing sludge production, although they did require a significant amount of energy.