# Optimized Analytical-Numerical Procedure for Ultrasonic Sludge Treatment for Agricultural Use
## 12 Conclusions  
This study introduced an innovative approach for sewage sludge treatment, combining ultrasonic and thermal treatments to optimize sludge management for agricultural \begin{table}
\begin{tabular}{c c c c} \hline \hline
\begin{tabular}{c} **Heavy Metals** \\ **[mg/Kg]** \\ \end{tabular} & **Sludge Analysis** \\ \hline Copper & 217–247 & Zinc & 203–357 \\ Cadmium & \textless{}1 & Mercury & \textless{}1 \\ Lead & 24–43 & Nickel & 17–30 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Characterization of the sludge processed and leaving the plant. purposes. The results demonstrated significant improvements in treatment efficiency, with several key advantages summarized below:  
* **Reduction of moisture content and improved stability**: The ultrasonic treatment, combined with thermal techniques, achieved a moisture content reduction of up to 20%. This improvement enhanced material stability, making it more suitable for agricultural use or further processing. * **Increased energy efficiency**: Compared to traditional methods, the proposed protocol reduced energy consumption by up to 60%, demonstrating that ultrasonic techniques can offer a cost-effective and environmentally sustainable solution for sludge treatment. * **Environmental benefits**: The method significantly reduced greenhouse gas emissions, human toxicity, and fossil fuel consumption, aligning the process with principles of circular economy and environmental sustainability. * **Validation at scale and practical applicability**: The protocol was validated both in laboratory and real-plant settings, confirming its feasibility for large-scale implementation in wastewater treatment systems. The proposed methodology adapts to industrial contexts without requiring costly structural interventions. In addition to these direct benefits, the study highlighted the effectiveness of the developed mathematical model, which integrates information on temperature, humidity, and pressure to optimize operational parameters. This approach enables scientifically supported treatment management, reducing operational costs and improving the quality of the final product. Despite the promising results, the study identified some limitations, including the need to improve the prototype's reliability during operation and address some energy efficiency issues. Future developments will focus on refining the prototype, testing processes on different types of sludge, and implementing advanced monitoring systems based on soft computing technologies to ensure continuous control of the treated material composition. In summary, the presented work addresses existing gaps in the literature, providing an innovative and sustainable solution for sewage sludge treatment. This study offers a solid foundation for further developments and applications in the wastewater treatment sector. Conceptualization, F.L., S.A.P., G.A. and M.V. ; methodology, F.L., S.A.P., G.A. and M.V. ; software, F.L., S.A.P., G.A. and M.V. ; validation, F.L., S.A.P., G.A. and M.V. ; formal analysis, F.L., S.A.P., G.A. and M.V. ; investigation, F.L., S.A.P., G.A. and M.V. ; resources, F.L., S.A.P., G.A. and M.V. ; data curation, F.L., S.A.P., G.A. and M.V. ; writing--original draft preparation, F.L., S.A.P., G.A. and M.V. ; writing--review and editing, F.L., S.A.P., G.A. and M.V. ; visualization, F.L., S.A.P., G.A. and M.V. ; supervision, F.L., S.A.P., G.A. and M.V. ; project administration, F.L., S.A.P., G.A. and M.V. ; funding acquisition, F.L., S.A.P., G.A. and M.V. All authors have read and agreed to the published version of the manuscript. This research has been supported by the Italian Ministry of University and Research under the Program PRIN 2022: \"Integration of Artificial Intelligence and Ultrasonic Techniques for Monitoring Control and Self-Repair of Civil Concrete Structures (CAIUS)\"--Code 2022 AZPLL8. Not applicable. Data Availability Statement: Data are contained within the article. The authors declare no conflicts of interest.