Background: The olive stone, a primary by-product of olive oil extraction, is mainly composed of a lignified shell and inner seed. It represents a substantial portion of the olive industry's biomass waste, contributing over 40 Mt annually. While typically regarded as waste, olive stones contain a variety of nutrients and bioactive compounds like lipids, proteins, phenolic compounds, and minerals found in the seed, as well as fibers in the shell. These elements hold significant value across multiple sectors, including food, energy, and agriculture. These phenolic compounds and nutrients provide notable antioxidant, anti-inflammatory, chemopreventive, and antimicrobial effects, supporting health and disease prevention. Scope and approach: This review explores the sustainable utilization of olive stone by-products, highlighting their potential to contribute to human health and environmental sustainability. It discusses the practical applications of olive stones in various domains, from functional ingredients in food products and pharmaceuticals to renewable energy sources and soil-enhancing agricultural inputs. Key findings and conclusions: Olive stones, particularly olive seeds, are rich in dietary fiber (47.6 %), lipids (30.4 %), proteins (13.5 %), and phenolic compounds (8.10 %), especially n & uuml;zhenide, n & uuml;zhenide 11-methyl oleoside and methoxyn & uuml;zhenide, and demonstrate a range of health-promoting properties. Additionally, they are shown to benefit metabolic health by combating disorders such as diabetes, hyperlipidemia, obesity, and car- diovascular and neurodegenerative diseases while also protecting organ functions like those of the liver and kidneys. The review underscores the promise of olive stone by-products as a sustainable, health-benefiting resource in circular economy practices within the olive oil industry.

Agricultural production is facing challenges such as water scarcity, declining soil quality, and excessive use of chemical fertilisers and pesticides, and there is an urgent need to find sustainable solutions. Hydrogel, as a novel functional polymer material, is considered as a potential agro-material to solve these problems due to its excellent water retention, swelling, slow release, biocompatibility and biodegradability. However, there are still challenges in designing efficient agrohydrogels, such as sustainability of the materials, environmental impacts of cross-linking methods, adaptability of the network structure to the crop growing environment, as well as the cost of the materials and the effectiveness of the practical applications. Therefore, a systematic review of the design, properties and applications of agrohydrogels is of great theoretical and practical significance. This paper reviews the design methods of agricultural hydrogels, including network structure design, material source selection, crosslinking technology and its mechanism research. Then, the key properties of agricultural hydrogels, such as water retention, swelling, slow release, biocompatibility and biodegradability, are discussed in detail. Finally, the applications of hydrogels in the fields of soilless cultivation, soil improvement and smart agriculture are presented. This paper concludes that with the continuous progress of technology, agricultural hydrogels will play an important role in future agricultural production.

Sewage sludge requires effective dewatering and high nutrients retention before disposal for agricultural application. Pressurized electro-osmotic dewatering (PEOD) process with low energy consumption can effectively remove water from sludge, but the influences of PEOD process on nutrients for agricultural application still lacks in-depth research. In this study, the influences of PEOD process on nutrients for agricultural application were investigated, including organic matter, nitrogen, phosphorus, potassium and silicon contents. Layered experiments were conducted to investigate the layered variation of nutrients in sludge and to understand the potential change mechanisms. The experimental results showed that PEOD process caused small losses (<10%) of organic matter and total phosphorus (TP) in sludge, but caused 11.2-18.4% loss of total nitrogen (TN). PEOD process also caused 18.6-27.0% loss of total potassium (TK) and over 80% loss of available potassium in sludge, and could weaken the potential salt damage during the agricultural application of sludge. Furthermore, the available phosphorus content of sludge in the anode area increased significantly after the PEOD process, indicating that PEOD process could enhance the phosphorus bioavailability of sludge in the anode area. Besides, PEOD process caused a slight loss of silicon components in sludge, but improved the long-term silicon dissolution and release ability of sludge. This work could expand the knowledge about the influences of PEOD process on sludge nutrients and provide scientific guidance for the agricultural application of PEOD sludge.