Dr. Eng. Salah Jellali currently holds the position of senior researcher in Water & Environmental Engineering at the Centre for Environmental Studies and Research (CESAR) of Sultan Qaboos University (SQU). His primary research focus revolves around local management and governance of solid and liquid wastes within the framework of circular economy and sustainability. A key area of his expertise involves the conversion of organic biomasses into high-value products such as biochars through pyrolysis process. Dr. Jellali has coordinated and participated in various national and international projects centered on the reuse of biochars as efficient adsorbents for wastewater treatment and/or as biofertilizers in agriculture. Additionally, he has actively contributed as a member of organizing and scientific committees for numerous international conferences on water and environment sustainable management. Dr. Jellali has supervised several PhD theses and Master students. Dr. Jellali has authored over 120 peer-reviewed scientific papers and book chapters and received the of best researcher award of SQU for the period 2020-2022.

The COVID-19 pandemic has drawn attention to the challenge of managing hazardous waste, such as masks and syringes. This study presents a sustainable plasma gasification system modelled on Aspen Plus V12 to treat hazardous medical waste. The system includes an extra Gibbs reactor to increase the lower calorific value of the syngas (LHV) and increase the mole fractions of H₂, CO, and CH₄. These wastes are medical waste from Turkey, masks from Indonesia, Korea, and Lithuania, and even syringes from China. Analysis results of syngas produced from various residues show that Korean masks produced the highest H2 content, Turkish medical waste produced the most CO, and Lithuanian masks generated the most CH₄. Turkish medical waste results in the lowest LHV syngas, while Korean masks achieved the highest. A sensitivity analysis optimised airflow, steam inlet, and torch temperature to enrich the syngas composition. For Turkish waste, the mole fractions of H₂, CO, and CH₄ increased from 42.7% to 84.3%. Lithuanian masks emerged as the most promising, producing syngas with an LHV of 10.647 MJ/m³ and hydrogen content of up to 85.7%. This work demonstrates an environmentally friendly so lution to hazardous and infectious waste, generating energy-rich syngas and inert slag useable in construction. The system has significantly improved the quality and efficiency of syngas, offering a scalable approach to waste treatment across different regions. The new conditions maximise efficiency, allowing for better energy recovery and broad applicability to waste from different regions.

The continuous depletion of fossil fuel resources has intensified environmental challenges, thereby driving the advancement of sustainable and environmentally friendly energy technologies. In this regard, rechargeable batteries have been considered as a ideal replacement of fossil fuels. Among them, there has been a growing research focus on lithium (Li) metal batteries (LMBs) due to their exceptionally high energy density. As the core component of LMBs, lithium metal anodes (LMAs) exhibit significantly higher capacity and lower redox potential compared to traditional graphite anodes, driving extensive investigation into their potential. However, LMAs face several interrelated challenges, including the formation of a solid electrolyte interphase (SEI), lithium dendrite growth, and substantial volume fluctuations. Recent studies have identified biomass- derived three-dimensional (3D) carbon hosts as a promising strategy to address these issues. These porous 3D carbon structures effectively regulate local current density and accommodate volume changes in LMAs, thereby mitigating SEI formation and suppressing dendritic lithium growth. This work systematically examines various 3D carbon host materials derived from diverse biomass sources and elucidates their mechanisms for improving the electrochemical performance of LMAs. Our work is anticipated to further inspire research on leveraging sustainable biomass sources for the design of 3D carbon hosts to enhance LMA performance.

The growing demand for sustainable aquaculture calls for innovative feed solutions that reduce reliance on conventional ingredients such as fishmeal and soybean meal, which compete with human food production. Circular economy principles promote the use of agricultural by- products as alternative feed ingredients, minimizing resource competition and waste.

In central Italy, small-scale trout (Salmo trutta fario and Oncorhynchus mykiss) farms have faced economic challenges due to regulatory restrictions on restocking non-native species and the economic impact of the 2016 earthquake in the Marche region. Many farms are struggling to remain operational, pushing the need for cost-effective and sustainable practices.

As part of the Horizon 2020-PRIMA AgrI-fiSh project (2022-2025), this study tested novel aquaculture feeds replacing up to 70% of conventional feed components with agricultural by- products. The experimental trials were conducted in a trout farm in Visso (Italy), testing two experimental diets (A and B) derived from legume and cereal processing waste and grape by- products, known for their antioxidant and fatty acid content.

Brown trout (n=900) were reared in nine tanks (three per diet) under controlled conditions. Growth performance and condition factor (K) were evaluated using one-way ANOVA and post-hoc Tukey’s test (p<0.05). While all groups showed increased total length, final body weight was lower in experimental diets compared to control.

Further studies on rainbow trout, as well as ongoing trials in Spain on seabass and in Algeria on tilapia, aim to refine these formulations and improve productivity, fostering a more sustainable and resilient aquaculture sector.