This chapter provided an overview of the physical properties of soils and their importance on the mobility of water and nutrients and the development of a vegetation cover. It also gives some examples of why the use of agricultural residues can affect positively soil physical properties. The incorporation of agricultural wastes can be a sustainable practice to improve soil characteristics, favoring a model of zero waste in agricultural production and allowing better management of soils. We review and analyze the effect of the use as amendments of different agricultural residues, on physical properties of the soil (e.g., bulk density, porosity, and saturated hydraulic conductivity), especially related to the movement of water in the soil.
Part of the book: Agricultural Waste and Residues
The European Union (EU) is one of the major producers of municipal solid wastes and has a common policy based on circular economy to reuse the wastes. However, there are differences between countries and the methods for disposal and treatments. Municipal solid waste (MSW) can be composted and recycled as a source of plant nutrients and improves soil properties. This chapter analyzed the production in the EU and the effects on plant nutrients and environmental pollutants when MSW is added to the soil. The origin of the waste and the compost-like output (CLO) derived is important to determine the expectative of nutrient availability and other possible risks. MSW is so heterogeneous, but after a good pretreatment, an organic-rich matter mix can be composted giving a stabilized organic matter. The addition of the CLO to the soils can improve the nutrient status and favor the bioavailability of nutrients (macronutrients and micronutrients). In general, an increment of N and P was found in the soils. Moreover, important micronutrient availability (Fe, Mn, Cu, and Zn) has been described. However, the presence of pollutants and their mobility should be considered as an environmental risk.
Part of the book: Municipal Solid Waste Management
Ultrasound (US) technology is already into the research field providing a powerful tool of producing nanomaterials or being implicated in decoration procedures of catalyst supports for energy applications and material production. Toward this concept, low or/and high-frequency USs are used for the production of nanoparticles, the decoration of catalytic supported powders (carbon-based, titania, and alumina) with nanoparticles, and the production of metal-organic frameworks (MOFs). MOFs are porous, crystalline materials, which consist of metal centers and organic linkers. Those structures demonstrate high surface area, open metal sites, and large void space. All the above produced materials are used in heterogeneous catalysis, electrocatalysis, photocatalysis, and energy storage. Batteries and fuel cells are popular systems for electrochemical energy storage, and significant progress has been made in nanostructured energy materials in order to improve these storage devices. Nanomaterials have shown favorable properties, such as enhanced kinetics and better efficiency as catalysts for the oxygen reduction reaction (ORR).
Part of the book: Nanotechnology and the Environment