The Reclaimed Water Reuse Plant, located in the northern area of the city of Alicante, constitutes essential infrastructure within the region’s integrated water cycle, especially in a context marked by structural water stress affecting the Mediterranean basin. This plant treats urban wastewater through activated sludge processes, anaerobic digestion, and an advanced tertiary treatment system that integrates ultrafiltration (UF) and reverse osmosis (RO) to ensure high-quality reclaimed effluent. The Reclaimed Water Reuse Plant serves a reference population of more than 350,000 population equivalents and is part of the regional reuse strategy led by EPSAR and Aguas de Alicante.
This project aims to increase the volume of reclaimed water intended for non-potable uses (irrigation of green areas, peri-urban agriculture, and municipal infrastructures), displacing the consumption of potable water in applications where such quality is not required. Specifically, it proposes a high-impact operational improvement based on increasing the efficiency of the UF-RO system from the current 75% to 80% overall recovery. This efficiency gain will be achieved through the incorporation of high-performance antiscalants capable of inhibiting the formation of mineral scaling on membranes, and biodispersants designed to minimize biofilm formation. This intervention will not only increase the volume of reclaimed water without modifying the influent flow but will also reduce the frequency of chemical cleanings (CIP), improving membrane lifespan and system operational stability. In terms of flow, it is expected to increase effective availability by more than m³/day, thus contributing to consolidating water resilience in Alicante’s urban and agricultural environment.
The metropolitan area of Alicante faces increasing pressure on its water resources due to the structural lack of rainfall, overexploitation of aquifers, and high seasonal demand, intensified by urban concentration and tourism during the summer months. This situation is aggravated by the low climate resilience of the Vinalopó-L’Alacantí basin, ranked among the most water- and ecologically-stressed areas of the Mediterranean region.
Historically, the irrigation of parks and gardens, sports facilities, and peri-urban agricultural areas has depended on high-quality potable water sources or overexploited groundwater abstractions. This practice is unsustainable and creates tensions among competing uses of the resource, compromising both urban water security and ecosystem conservation.
Despite having a Reclaimed Water Reuse Plant equipped with advanced technologies, the effective utilization of reclaimed water remains well below its potential. The main causes include the lack of secondary distribution infrastructure (such as separate irrigation networks), administrative and regulatory barriers hindering implementation, and weak coordination among end users, water cycle managers, and municipal authorities. Added to this is the limited operational efficiency of the tertiary treatment, which currently only recovers around 75% of the treated flow. This means that, even when there is unmet demand for reclaimed water, the effective production capacity is constrained by technical factors that require immediate optimization to move toward a circular water economy at the urban scale.
The project proposes to establish an integrated and scalable system for reclaimed water reuse from the Reclaimed Water Reuse Plant, based on three interdependent pillars:
This integrated approach ensures not only an increase in the volume of reclaimed water utilized but also the consolidation of an adaptive and resilient management model aligned with the requirements of the VWBA 2.0 framework.
The technical implementation of the project includes the integration of a set of technologies and actions aimed at maximizing efficiency, traceability, and sustainability of the tertiary treatment system at the Reclaimed Water Reuse Plant. The core of the project relies on advanced tertiary treatment using ultrafiltration (UF) and reverse osmosis (RO), which produce high-quality effluent suitable for demanding non-potable uses. UF acts as a physical barrier for suspended solids, viruses, and bacteria, while RO removes dissolved salts, emerging contaminants, and micro-organic pollutants, reaching standards comparable to potable water for specific applications.
A key proposed improvement is the incorporation of next-generation antiscalants and specialized biodispersants. These advanced chemicals prevent mineral scaling and biofilm formation on membranes, two factors that traditionally reduce the hydraulic and energy efficiency of the system. This intervention is expected to increase the UF/RO system recovery rate from 75% to 80%, significantly increasing the daily volume of reclaimed water available without increasing influent flow or modifying existing infrastructure.
The operation will be supported by an intelligent monitoring network based on SCADA technology. This system will enable real-time supervision of parameters such as flow, pressure, turbidity, conductivity, and residual chlorine, ensuring operational stability and safety. The data will be integrated into the Aqua Positive digital platform via API to ensure external traceability and validation of the generated impact, facilitating reporting under frameworks like CDP Water or European ESRS.
From a field monitoring perspective, multiparameter sensors will be strategically located throughout the system, both within the plant and in the secondary distribution network to be developed as part of this project. This network will channel reclaimed water to identified priority consumption points: municipal green spaces, sports facilities, nurseries, and peri-urban agricultural areas.
Finally, implementation will be carried out through a network of key partnerships. EPSAR, as the infrastructure owner, will ensure regulatory viability and operational sustainability; Aguas de Alicante, as the technical operator, will execute and maintain the operational improvements; the City of Alicante will facilitate urban integration of reclaimed water into green space and service planning; and peri-urban irrigation communities will act as strategic end users, enabling a rural-urban synergy that maximizes the project’s impact.
This technological and operational integration forms a robust and replicable proposal that positions the Reclaimed Water Reuse Plant as a benchmark for water reuse in the Mediterranean region.
The project is being developed in a phased approach to ensure technically and operationally effective implementation, starting with the identification and prioritization of areas where reclaimed water use represents a real opportunity to substitute potable water. This stage involves territorial diagnostics in collaboration with the municipality and local stakeholders to select spaces such as public parks, nurseries, sports fields, and peri-urban horticultural sectors.
In parallel, operational adaptation of the plant’s tertiary treatment train is addressed. This includes actions such as optimizing chemical cleaning (CIP), adjusting backwash sequences, and controlling both organic and inorganic fouling. The introduction of specific antiscalants and biodispersants will allow sustained improvement in UF/RO system efficiency without altering existing infrastructure.
Once production efficiency improvements are secured, construction of a secondary distribution network will proceed. This network will be technically tailored to the type of use and will include pressure-regulating valves, flowmeters, and controlled delivery points. Its design will prioritize proximity, ease of connection, and integration with existing irrigation networks.
Finally, a comprehensive control system will be activated, including real-time sensors, digital platforms for traceability of reused volumes, and external validation mechanisms. This phase will also include training for operational staff and the establishment of protocols for systematic data reporting.
Beyond the immediate improvement in system efficiency and the increase in reclaimed water availability, this intervention represents a replicable model for other Reclaimed Water Reuse Plants in Mediterranean coastal zones. Its value lies not only in the amount of water reused but in the potential to consolidate resilient urban infrastructure aligned with circular water economy principles and climate change adaptation.
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