The Industrial Park, located in a coastal area of western Cantabria, hosts various manufacturing, food, and logistics activities. Many of these generate wastewater with differentiated pollutant loads, such as organic matter, industrial detergents, mineral oils, or traces of heavy metals. This heterogeneity makes the zone a critical point in terms of wastewater management. Despite its strategic importance for regional economic development, the park lies within the Nansa River basin, an area recognized for its high biodiversity and ecological sensitivity, which has led to increasingly strict restrictions on surface and groundwater extraction.
Given this context, the project proposes the design and installation of a modular tertiary treatment plant specifically adapted to the variability of effluents in the park. This facility will feature a technological sequence based on physical, chemical, and biological modules that enable operational flexibility without compromising efficiency. Its configuration includes fine screening, dissolved air flotation (DAF), membrane bioreactors (MBR), ultrafiltration, and UV disinfection — all integrated into a centralized SCADA system with IoT sensorization. The infrastructure will enable safe reuse of the treated water by multiple companies in the park, ensuring compliance with regulatory limits and promoting a circular water economy.
System operation will be governed by a shared governance model involving businesses, local authorities, and environmental entities, with digital traceability of all input and output flows enabled through an optional DLT system. This solution aligns with the technical principles of the VWBA 2.0 framework, and it is projected to allow recovery of over 80,000 m³ of high-quality regenerated water per year. In parallel, the initiative will transform the park into a true hub for circular water economy, combining water regeneration and reuse with technical training, participatory governance, collaborative environmental investment, and integration into municipal and regional water resilience plans.
The Industrial Park faces a critical water situation due to multiple converging factors. On one hand, the high demand for water in industrial processes, including cleaning, cooling, production, and sanitization, exerts significant pressure on local freshwater sources. This pressure is compounded by the absence of recovery or reuse mechanisms, rendering current consumption essentially consumptive.
On the other hand, many of the generated effluents lack adequate treatment before discharge, which has led to progressive deterioration of nearby receiving bodies. This includes the disruption of natural nutrient balances, increased organic load, and the presence of emerging contaminants, all of which have negative effects on aquatic biodiversity and water quality for other uses.
From a regulatory standpoint, the tightening of discharge limits and pressure to reduce water withdrawals have introduced new compliance demands that particularly affect SMEs in the park, which often lack the financial capacity for individual investment in treatment infrastructure. This has created operational and legal inequality, where some companies comply using low-efficiency on-site solutions, while others face sanctions and restrictions.
Lastly, the absence of shared treatment infrastructure has led to a fragmentation of responses, high individual operational costs, and a lack of traceability for both treated flows and the quality of regenerated or discharged water. This creates a high water-related risk, physical, regulatory, financial, and reputational , that threatens the medium-term sustainability of operations unless a collective, technical, and structural solution is adopted.
The proposed solution is based on a modular tertiary treatment architecture, designed to adapt to variable flow rates and heterogeneous contaminant profiles typical of the park. The system includes an integrated sequence of processes comprising:
– physical pretreatment through automatic screening and induced flotation sedimentation (DAF),
– biological treatment using membrane bioreactors (MBR) with F/M load control,
– ultrafiltration via hollow fiber membranes capable of removing particles >0.02 microns,
– advanced oxidation combining hydrogen peroxide and ultraviolet radiation to reduce emerging contaminants and recalcitrant organic traces,
– final disinfection without chlorine using double-pass UV light equipped with cumulative dose sensors.
The system is automated through a SCADA network connected to IoT sensors installed at critical points (effluent entry, post-ultrafiltration, storage tank, internal distribution lines). These sensors monitor in real time parameters such as flow rate, turbidity, conductivity, pH, ORP, total dissolved solids, and specific compounds such as ammoniacal nitrogen or phosphates. All this information is managed through a unified digital platform that allows full traceability of the regenerated water cycle, from its origin to its final use , which is essential for the transparent allocation of water benefits under the VWBA/WQBA approach.
Additionally, a framework agreement will be established between companies, the municipal council, and the Cantabrian River Basin Authority, with three key objectives:
The implementation process is structured in four interconnected phases combining detailed engineering, physical execution, assisted operation, and community scaling. Each phase serves specific technical and strategic functions, with clear objectives, metrics, and controls to ensure both technical and social success.
Phase 1 (Design and Permitting, Months 0 to 6): The process begins with a thorough technical diagnosis of effluents generated by each company in the park. Representative samples are taken at various times and days, measuring parameters such as BOD₅, COD, settleable solids, trace metals, and surfactants. Using this data, a hydraulic and pollutant load model is developed, enabling the design of a collector system capable of managing peak flows and mixed contributions.
Subsequently, engineering plans are drawn for the modular plant, specifying the appropriate treatment train based on the contaminant matrix. Combined physical-chemical-biological treatment technologies (screening, DAF, MBR, ultrafiltration, AOP, UV) are selected, and key indicators are defined: removal efficiency per parameter, specific energy consumption (kWh/m³), volume regenerated, and output quality metrics. A baseline is also established to measure future water benefits.
During this phase, the technical and environmental dossier is prepared to request discharge and reuse authorization from the Cantabrian River Basin Authority. This includes cumulative impact modeling, an ecosystem sustainability report, and hydrological simulations. In parallel, a participatory process is conducted to consolidate the multi-stakeholder governance model, including rules for regenerated volume allocation, usage priorities, tariff structure, and shared monitoring commitments.
Phase 2 (Construction and Connection, Months 6 to 12): This phase marks the start of construction. Conveyance networks are built using HDPE materials, with inspection and bypass systems incorporating automatic valves. Support structures for the treatment modules are constructed on seismic-resistant slabs with drainage chambers and technical access. The plant is assembled using transportable modules, allowing for individual maintenance and future expansion.
Each treatment unit is equipped with inline sensors that measure turbidity, ORP, conductivity, pH, ammonium, nitrates, and flow. All data are integrated into a SCADA system with redundant power supply and cloud connectivity, allowing real-time operational control and automated reporting. Electromagnetic flowmeters and energy meters are also installed. This phase includes technical training for operational staff, preventive maintenance procedures, and contingency management. Dry tests and simulations with synthetic water are conducted before actual operation begins.
Phase 3 (Commissioning and Validation, Months 12 to 18): During this phase, the system begins operating with real effluents. Flows from each company are gradually introduced to avoid hydraulic shocks or biological imbalances. Operating cycles of 24 to 72 hours are set to verify stability of critical parameters, and the performance of each operational unit is documented.
Simultaneously, thorough monitoring is conducted through continuous measurement and spot sampling to validate key quality parameters of the regenerated water. Mass balances are calculated and compared with the baseline to determine volumetric benefits over time. A technical audit is then carried out following VWBA 2.0 and WQBA methodologies, including document review, operational interviews, and data cross-validation.
Phase 4 (Community Scaling, Months 18 to 36): In this final phase, system operation is consolidated and scaled. New companies are integrated through hydraulic branches, adjusted discharge schedules, and revised accepted contaminant loads. Eligibility criteria are defined, contribution limits are established, and usage tariffs for shared infrastructure are adjusted.
This phase also formalizes recognition of the project as a Water Positive initiative on the Aqua Positive platform, facilitating new financing streams and international visibility. The resulting economic benefits are reinvested in nature-based solutions within the basin: infiltration trenches, artificial wetlands, riparian corridor restoration, and participatory community monitoring. Additionally, open educational activities, technical visits, dual training programs, and partnerships with regional universities are developed.
Each phase integrates technical, management, and governance actions, transforming the park’s water management into a replicable circular water economy model with quantifiable, permanent, and traceable benefits.
The industrial water reuse project in the Industrial Park in Cantabria is a structural response to the water challenges faced by this diverse and environmentally sensitive industrial area. Located within the Nansa River basin, the park hosts manufacturing, food, and logistics activities that generate wastewater with highly variable contaminant profiles, including organic matter, oils, industrial detergents, and traces of heavy metals. In the absence of a collective solution, the fragmented management of these discharges has placed increasing pressure on receiving water bodies and on freshwater sources, both surface and groundwater, which are subject to increasingly strict extraction limits.
This project proposes the construction and operation of a modular tertiary treatment plant specifically designed to adapt to variability in both volume and quality of the effluents. The proposed infrastructure integrates advanced technologies in a compact and efficient sequence including fine screening, dissolved air flotation (DAF), membrane bioreactors (MBR), hollow fiber ultrafiltration, advanced oxidation processes combining hydrogen peroxide and ultraviolet radiation, and a final chlorine-free disinfection stage using dual-pass UV with accumulated dose sensors. This configuration enables the production of high-quality regenerated water, compliant with regulatory thresholds and suitable for safe reuse among multiple industrial users in the park.
The system is equipped with a network of IoT sensors installed at critical process points (influent, post-ultrafiltration, storage tank, internal distribution lines), which continuously monitor parameters such as turbidity, ORP, conductivity, pH, ammonium, nitrates, phosphorus, and total dissolved solids. All this information is integrated in real time into a SCADA platform with backup power and cloud connectivity, enabling full digital traceability of operations. The project also provides the option to integrate DLT for decentralized certification of water flows and transparent allocation of water benefits, in accordance with the VWBA 2.0 framework and its water quality extension, WQBA.
Execution of the plant is organized under a shared governance model involving user companies, the local municipality, and the Cantabrian River Basin Authority. This model not only regulates allocation and prioritization of regenerated water based on sustainability and water security criteria, but also establishes a strategy to reinvest operational benefits into local resilience measures. These include aquifer recharge through infiltration trenches, restoration of riparian corridors, and the construction of artificial wetlands as nature-based solutions within the basin.
The infrastructure is designed to be scalable and replicable, with the ability to progressively integrate new companies via hydraulic extensions, adaptive treatment capacity, and flexible tariff structures. In parallel, the project promotes a strong educational and community engagement component through technical visits, dual-training programs, partnerships with regional universities, and public awareness activities.
With a projected recovery capacity exceeding 80,000 m³ per year of high-quality regenerated water, the project makes a significant contribution to reducing consumptive freshwater use, improving effluent quality, enhancing regional water resilience, and transforming the industrial park into a true hub of circular water economy. This transformation not only aligns with multiple Sustainable Development Goals (SDGs) but also sets a precedent for industrial water innovation in northern Spain.
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