Wastewater treatment plant effluents can be an important source of contamination in agricultural reuse practices, as pharmaceuticals are poorly degraded by conventional treatments and can enter crops, thereby becoming a toxicological risk. Therefore, advanced tertiary treatments are required. Ozone (O₃) is a promising alternative due to its capacity to degrade pharmaceutical compounds, together with its disinfecting power. However, mass transfer from the gas to the liquid phase can be a limiting step. A novel alternative for increased ozone efficiency is the combination of micro-nano bubbles (MNBs). However, this is still a fairly unknown method, and there are also many uncertainties regarding their implementation in large-scale systems. In this work, a combined O₃/MNBs full-scale system was installed in a WWTP to evaluate the removal efficiency of 12 pharmaceuticals, including COVID-19-related compounds. The results clearly showed that the use of MNBs had a significantly positive contribution to the effects of ozone, reducing energy costs with respect to conventional O₃ processes. Workflow and ozone production were key factors for optimizing the system, with the highest efficiencies achieved at 2000 L/h and 15.9 gO₃/h, resulting in high agronomic water quality effluents. A first estimation of the transformation products generated was described, jointly with the energy costs required.

Wastewater reuse presents a promising way to mitigate the risk to global water resources and achieve sustainability in water, especially in agricultural areas in the southeast of Spain, such as the Murcia region. However, the risks related to the presence of contaminants of emerging concern (CECs) or pathogenic microorganisms in wastewater treatment plant (WWTP) effluent suggest the need to implement effective and relatively low-cost tertiary treatments. With this aim, a self-sustainable pilot prototype based on three combined modules (disc-filtration, granular activated carbon (GAC) bed adsorption and UV disinfection) assisted by solar panels was installed as an alternative tertiary treatment in a conventional WWTP in the Murcia region. The obtained results clearly confirmed the efficiency of the proposed prototype for CECs removal, and showed optimal results at a workflow of 500 L/h. In all cases, high removal efficiency was obtained for the different indicator microorganisms described in the recently published Regulation (EU) 2020/741 (E. coli, F-specific coliphages, somatic coliphages, total coliphages, and Clostridium perfringens). The protection of the activated carbon by disc-filters and the energy autonomy and self-operation of the prototype resulted in an efficient and economically viable methodology for its implementation in both conventional WWTPs and in isolated areas attached to crops.

The water footprint is an increasingly demanded environmental sustainability indicator for certifications and labels in agricultural production. Processing tomatoes are highly water-intensive, and existing studies on water footprint have uncertainties and do not consider the impact of different irrigation configurations (e.g., surface drip irrigation (SDI) and subsurface drip irrigation (SSDI)) and irrigation strategies. This study presents a two-year experimental investigation to determine the water footprint of processing tomatoes grown in southern Spain (Andalusia) and the impact of SSDI and deficit irrigation. Five irrigation treatments were established: SDI₁ (surface drip irrigation without water limitation), SDI₂ (surface drip irrigation without water limitation adjusted by soil moisture readings), SSDI₁ (subsurface drip irrigation without water limitation and a dripline depth of 15 cm), SSDI₂ (similar to SSDI₁ but with mild/moderate water deficit during the fruit ripening stage), and SSDI₃ (subsurface drip irrigation without water limitation and a dripline depth of 35 cm (first year) and 25 cm (second year)). Measurements included crop vegetative growth, leaf water potential, leaf gas exchange, nitrate concentration in soil solution, and crop yield and quality. The soil water balance components (actual evaporation, actual transpiration, deep drainage), necessary for determining the total crop water footprint, were simulated on a daily scale using Hydrus 2D software. Results indicated that SSDI makes more efficient use of irrigation water than SDI. The water footprint of SSDI₁ was 20–35% lower than that of SDI₁. SSDI₂ showed similar water footprint values to SDI₁ under highly demanding environmental conditions and significantly lower values (≈40%) in a year with lower evaporative demand. The dripline depth in SSDI was critical to the water footprint. With a 35 cm installation depth, SSDI₃ had a significantly higher water footprint than the other treatments, while the values were similar to SSDI₁ when the depth was reduced to 25 cm.

Últimamente se han realizado avances para determinar la dosis de riego a aplicar en el viñedo en función de los objetivos productivos y enológicos. El reto que aborda este trabajo es tener en cuenta la variabilidad espacial en las parcelas para ajustar el riego a las posibles diferencias existentes. Para ello, la metodología utilizada integra técnicas de teledetección de rango cercano utilizando drones y modelos hidráulicos de precisión para llevar a cabo una zonificación de un viñedo comercial de la variedad Monastrell situado en la DO Jumilla para definir tres zonas con distintos índices de vigor vegetativo. Posteriormente, durante tres campañas consecutivas, se ha aplicado un riego diferencial para cada zona de modo que, manteniendo la dosis promedio establecida de unos 1000 m3/ha, la misma ha sido aplicada de forma diferencial en función del vigor de las cepas, aplicando más agua a la zona con una mayor vigorosidad. Para ello se ha variado el diseño agronómico del riego, utilizando distintas distancias entre goteros en función de la zonificación realizada. De este modo, sin tener que sectorizar ni aplicar tiempos o frecuencias de riego distintas para cada zona, el volumen de agua aplicado por la instalación fue distinta. Dicha estrategia de riego de precisión ha sido validada en campo, demostrando que las zonas de mayor vigor vegetativo han aprovechado mejor la mayor dotación de riego empleada teniendo una mayor producción frente a otras zonas con menor desarrollo vegetativo donde se ha considerado que la productividad de las cepas podía estar limitada por otros factores al margen del riego. Además, las distintas zonas previamente delimitadas, han proporcionado calidad de uva diferenciada. Mediante el procedimiento descrito, se puede por lo tanto adaptar el riego en parcela en función de la variabilidad existente modulando así la respuesta del viñedo