• Energy Research

Jujube fruit (Ziziphus jujuba Mill.) has been a food source since ancient times. In Spain, it is considered a marginal crop, and jujube fruits are of low economic importance. Its consumption is bound to local marketplaces. However, jujube is a good alternative crop due to its climatic adaptation and low-input conditions. We aimed to evaluate the morphological, physicochemical, and bioactive compounds of jujube fruits grown under low-input conditions (wild and organic farming) in the Mediterranean basin, specifically in Marjal de los Moros, Valencia, Spain. The organic system produces higher protein, fiber, ash, and carbohydrate concentrations from small-caliber fruit cultivars. Potassium and phosphorus are the major mineral elements in jujube. The fruits’ total polyphenols range from 480.83 to 630.81 mg EGA·100 g−1 fw in organic conditions and 520.71 mg EGA·100 g−1 fw in wild conditions. Low-input conditions influence the production of glucose (sweet fruits) and bioactive compounds, as well as mineral concentrations. A strong relationship exists between vitamin C levels and the potassium concentration. Jujube fruits are classified as “vitamin C-rich”. A 20 g serving of fruit can provide the regular vitamin C requirements of an adult person. The environmental and nutritional opportunities offered by jujubes are in line with different SDGs.

[EN] The objective of this research is to analyse the feasibility of reusing the fly ash waste, which is produced in biomass plants, during the production of renewable energy, for controlling phosphorus contamination in the wastewater being processed in sewage treatment plants. The research examines the efficiency of using different types of ash, obtained from representative biomass materials after combustion in an energy plant (paulownia wood, wheat straw and barley straw), in removing phosphorus from water. The ashes were respectively mixed with synthetic water, rich in phosphorus; then, using batch experiments, the effects that the pre-treatment of ash, adsorbent dosage, contact time and temperature had on the adsorption process were studied. The main results show that phosphorus adsorption by the tested ashes augments as temperature increases. Similarly, the adsorbed amount of phosphorus increases by increasing the dose of the adsorbent. In addition, the adsorption of phosphorus by these three materials has been described well by the Langmuir isotherm equation. It has been found that the removal process of phosphorus was endothermic. Finally, this study concludes that waste ash from biomass plants can be used to remove phosphorus from wastewater in sewage treatment plants.