Residues and by-products from vegetables and fruit wholesale markets are suitable for recovery in the form of energy through anaerobic digestion, allowing waste recovery and introducing them into the circular economy. This suitability is due to their composition, structural characteristics, and to the biogas generation process, which is stable and without inhibition. However, it has been observed that the proportion of methane and the level of degradation of the substrate is low. It is decided to study whether the effect of pretreatments on the substrate is beneficial. Freezing, ultrafreezing and lyophilization pretreatments are studied. A characterization of the substrates has been performed, the route of action of pretreatment determined, and the digestion process studied to calculate the generation of biogas, methane, hydrogen and the proportions among these. Also, a complete analysis of the process has been performed by processing the data with mathematical and statistical methods to obtain disintegration constants and levels of degradation. It has been observed that the three pretreatments have positive effects, when increasing the solubility of the substrate, increasing porosity, and improving the accessibility of microorganisms to the substrate. Generation of gases are greatly increased, reaching a methane enrichment of 59.751%. Freezing seems to be the best pretreatment, as it increases the biodegradation level, the speed of the process and the disintegration constant by 306%.

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Tomato is one of the most common crops across the world, but it is also one of the types of food that generates the most losses across its life cycle. This paper addresses this issue by providing a Life Cycle Analysis of greenhouse grown tomato in southern Spain. The results confirm that tomatoes are a thirsty and frail crop. Most of its energy demands and carbon emissions go to packaging (35%) and transportation (42%) as well as supplying water for their growth. There seems to be room for improvement in the recovery of energy (54.6%) and CO2 emissions, mainly addressing the waste treatment of packaging and plastic as well as improving transportation. Despite being highly water demanding, irrigation processes are already efficient in industrial greenhouses, and most of the water recovery will need to take place in the waste recovery stage. Food losses at the consumption phases do not constitute a significant loss in energy or a significant amount of carbon emissions saved.

Salinas and saltscapes are relevant geoheritage sites with important implications on socioeconomic activities beyond the production of salt, particularly tourism and education. As cultural landscapes, they also have implications related to the identity of their communities. This work presents the study of the patrimonialization processes of four sites in Europe (Añana in Spain, Guérande in France, Læsø in Denmark, and Sečovlje in Slovenia). Lessons obtained from these processes may contribute to the recovery and valuation of similar saltscapes and other forms of geoheritage. The study is based on interviews with relevant stakeholders, a survey of the related grey and scientific literature, and a simplified SWOT analysis. Despite their differences in historical background and current management, all four sites share features that have contributed to the success of their patrimonialization processes, such as having a dedicated entity for this purpose or being protected in some way. They also share common threats that need to be addressed, such as the banalization of the heritage discourse. Other saltscapes and geoheritage sites in general may benefit from these common features, which should serve as an inspiration and not as a template. In the end, shifting from a little-known productive, (proto-)industrial activity toward a sustainable, multifunctional landscape in which geoeducation and tourism are paramount contributes to a more resilient and educated society.

La patrimonialización de las salinas tradicionales en desuso puede ser una forma no sólo de recuperar su patrimonio, sino también una herramienta para el desarrollo local sostenible que va más allá de estos valores. Un estudio realizado en doce salinas europeas (nueve en España y tres en Dinamarca, Eslovenia y Francia, respectivamente) que se encuentran en diferentes etapas de patrimonialización muestra diferentes estrategias de recuperación del patrimonio; los obstáculos que se han encontrado en el camino y cómo (algunos de ellos) se han resuelto. Mediante un estudio comparativo de estas salinas, podemos identificar buenas prácticas y sacar conclusiones sobre lo que funciona o no a la hora de valorar el patrimonio natural, cultural y humano de estos espacios. En los doce casos se pueden observar diferentes grados de patrimonialización, algunos incipientes, otros en curso y otros ya consolidados; y se explican las diferencias entre ellos. Los procesos consolidados son los que muestran cómo el carácter multifuncional de los paisajes salados puede utilizarse para ofrecer una amplia gama de productos y servicios que van más allá de la producción de sal. Todos los casos, antes de su abandono, eran paisajes productivos dedicados al monocultivo de la sal, sin interés en preservar sus valores naturales y culturales más allá de lo estrictamente necesario para garantizar una mínima productividad. Las enseñanzas extraídas de los casos estudiados pueden servir de modelo para otros tipos de patrimonio productivo modesto en las zonas rurales. Asimismo, se discuten los retos de futuro en la patrimonialización de las salinas.

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RESUMEN:Pese a que la sal se considera perniciosa para la vida, los paisajes de la sal y, más en concreto las salinas de evaporación solar, constituyen complejos sistemas biológicos de gran relevancia para la producción de sal de calidad. No se trata sólo de la biodiversidad de especies halófilas que pueda habitarla o de las estrategias fisiológicas que la biota de las salinas tenga para sobrevivir a la sal en el ambiente, sino del entramado de relaciones que entre ellos se  producen. El delicado equilibrio entre la red trófica de las salinas con la actividad de producción artesanal de sal, hacen que sean paisajes vivos, que garantizan la conservación de sus valores naturales y culturales. La producción artesanal de sal se puede considerar así una actividad agrícola que resulta en un producto de alta calidad y respetuoso con el medionatural.ABSTRACT:Although salt is considered harmful to life, saltscapes and, more specifically, solar evaporation salinas, are complex biological systems of great relevance to the production of quality salt. It is not only a question of the biodiversity of halophilic species that may inhabit them or the physiological strategies that their biota have to survive the salt present in the environment, but also of the network of relationships between them. The delicate balance between the trophic network of the salinas and the artisanal salt production, make them living landscapes, which guarantee the conservation of their natural and cultural values. Artisanal salt production can thus be considered an agricultural activity that results in a high quality product that is respectful of the naturalenvironment.

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