The Water Reuse Plant, located in the Marina Baixa region of Alicante, represents a cornerstone of the city’s integrated urban water management strategy and stands as a national reference for sustainable water practices along the Spanish Mediterranean coast. This facility plays a critical role in ensuring water security for a city that experiences intense seasonal population growth, driven by tourism, coupled with chronic water scarcity and increasing environmental and regulatory pressures.
To respond to these challenges, the plant has undergone successive modernization phases, each focused on enhancing circularity in water use, minimizing greenhouse gas emissions, and promoting the efficient recovery and reuse of non-conventional water resources. The Water Reuse Plant not only contributes to reducing dependence on aquifers and reservoirs, already under significant stress due to climate variability and historical overexploitation, but also ensures a reliable supply of high-quality reclaimed water for non-potable applications such as park irrigation, agricultural use, and ecological support flows.
Within this broader sustainability framework, the current project represents a new milestone in the plant’s evolution. It aims to substantially improve the operational efficiency and performance of the tertiary treatment line, specifically targeting the ultrafiltration (UF) and reverse osmosis (RO) units. These advanced membrane processes are essential for achieving water quality standards required for reuse, but they are also prone to operational issues such as scaling, fouling, and reduced membrane lifespan.
The intervention includes the deployment of next-generation antiscalant and biodispersant formulations, tailored to the specific ionic composition of the feed water, as well as the optimization of Cleaning-In-Place (CIP) protocols through precision control of key variables such as pH, temperature, and contact time. Furthermore, the project integrates enhanced digital monitoring systems, linked to the plant’s SCADA platform, that allow real-time tracking of operational parameters and adaptive management of membrane performance.
The main objective is to increase the current RO water recovery rate from approximately 70% to a target range of 75% to 78%, a substantial improvement that translates directly into greater volumes of reclaimed water available for beneficial use. This enhanced efficiency not only contributes to the sustainability goals of the municipality and regional water authorities but also strengthens Benidorm’s role as a model city in the transition toward climate-resilient and water-positive urban systems.
Currently, the RO system presents operational limitations due to fouling (organic and biological) and the formation of mineral scaling, mainly calcium carbonate, silica, and phosphates. These phenomena reduce permeate flow, raise operating pressures, increase cleaning frequency, and shorten membrane life. Additionally, the existing CIP protocols are of limited effectiveness due to suboptimal sequences and the non-specific use of chemical products in both UF and RO.
These deficiencies must be analyzed within a broader hydrological context. Benidorm historically sources water from the Amadorio reservoir and underground wells in the Marina Baixa basin, as well as transfers from the Guadalest reservoir. However, the region faces increasing water stress due to the high seasonality of demand linked to tourism, overexploitation of aquifers, and the decline in average rainfall over recent decades. The dependence on conventional sources has forced the municipality to strengthen reuse as a strategic alternative, where the Benidorm WATER REUSE PLANT plays an essential role as a supplier of reclaimed water for irrigating parks, sports fields, and agricultural zones.
The current inefficiencies in the RO stage compromise not only the system’s technical sustainability but also the municipality’s capacity to maintain a stable and high-quality alternative water source. Addressing these limitations is key to ensuring continuity in reclaimed water supply, especially during peak summer demand.
The proposal is based on an integrated strategy of chemical, operational, and digital improvement, aimed at effectively resolving the main bottlenecks in the performance of UF and RO stages. This strategy includes:
This approach will allow for a net water recovery rate above 75%, with sustained improvements in permeate quality, fewer cleaning cycles, and a reduction in specific energy consumption per cubic meter treated.
Technologies or Actions Applied:
The system optimization is based on the incorporation of advanced chemical formulations specifically designed to prevent scaling and biofouling in UF and RO membranes. These products are formulated based on the ionic composition and physical-chemical characteristics of the treated water and are compatible with the membrane materials used in the plant. Dosing will be adjusted according to operational parameters and inlet water quality and managed via a fully automated system integrated into the facility’s SCADA, enabling continuous control and real-time adjustments.
Additionally, CIP protocols in both treatment stages will be reviewed and reformulated. Separate sequences of acid and alkaline cleaning will be established under optimal conditions of temperature, pH, and duration, adapted to the predominant type of fouling. Operational staff will be trained in the new protocols, and specific performance indicators will be implemented to validate cleaning effectiveness and extend equipment lifespan.
Monitoring Plan:
Technical-operational monitoring will include the installation and calibration of differential pressure sensors (ΔP), permeate flow meters, conductivity, and temperature sensors at critical system points. These instruments will allow real-time detection of deviations in hydraulic or water quality behavior that could signal a need for intervention. Specific membrane fouling tests, microbiological analyses to evaluate biological activity in the system, and systematic comparisons to the pre-intervention baseline will be conducted. Detailed records of chemical consumption and CIP frequency will be maintained to evaluate improvements in efficiency and sustainability.
Partnerships or Implementing Stakeholders:
Technical execution will be led by EPSAR, as the responsible operator of the WATER REUSE PLANT, in coordination with chemical solution providers experienced in tertiary treatment and membrane processes. Recipient municipalities of the reclaimed water—such as Benidorm, L’Alfàs del Pi, and La Nucía—will participate in performance validation and planning of final uses. These partnerships will ensure that the implemented improvements not only optimize internal plant operations but also deliver direct benefits to the regional distribution and reuse system.
The project involves a progressive, technically structured intervention divided into three main phases, conceived not only as an operational improvement but as a comprehensive urban sustainability strategy. The first phase includes an exhaustive operational diagnosis of the WATER REUSE PLANT, including the characterization of biofouling and scaling in UF and RO membranes, historical analysis of CIP operations, and hydraulic system performance. This stage will also include controlled pilot tests with different antiscalant and biodispersant formulations to select the most effective combination based on inlet water quality and specific system conditions.
The second phase focuses on the operational implementation of the optimized CIP protocols. These will include the application of specific chemical sequences with dynamic control of pH, temperature, contact times, and cleaning frequencies, all managed through the SCADA system. The chemical dosing system will also be modernized, automating critical process points and improving traceability and responsiveness to fouling events in real time. This phase is key to establishing an intelligent and adaptive operational dynamic that reduces operating costs and maintenance frequency.
Finally, the third phase will focus on technical validation and monitoring of real-world performance results. Key performance indicators (water recovery rate, permeate quality, specific energy consumption, CIP frequency, and membrane lifespan) will be compared to the previous baseline. A validated technical report will be produced, serving as a reference for scaling this methodology to other treatment plants within the EPSAR-managed system.
This project is part of Benidorm’s water strategy, a city recognized as a pioneer in integrating circular economy principles, water efficiency, and climate change adaptation into its urban model. By improving the performance of a key infrastructure in a water-stressed basin like Marina Baixa, it reinforces water security for the population, ensures continuous supply of reclaimed water for irrigation, and reduces pressure on natural resources. Moreover, this intervention constitutes a replicable model of technical and territorial sustainability in coastal tourist areas facing similar challenges.
© 2025 Aquapositive. All rights reserved. Further distribution is not permitted without authorization from Aquapositive.
