This project aims to transform the water management model in the intensive agriculture sector of the Campo de Níjar, by leveraging reclaimed water from urban wastewater treatment plants that currently discharge their effluents into the environment without productive use. The intervention focuses on constructing a technical system for the capture, storage, advanced treatment, and distribution of reclaimed water for agricultural irrigation, prioritizing producers linked to the horticultural supply chains of agribusinesses, particularly in potato, onion, and tomato crops.
The initiative is based on an active collaboration model with local Irrigation Communities (notably CR San Isidro and CR Níjar Norte), which will act as operational entities for the agricultural distribution service, facilitating both territorial integration and social acceptance of reclaimed water use. This approach significantly reduces groundwater abstraction from the overexploited aquifers of Campo de Níjar and Bajo Andarax while enhancing the climate and operational resilience of the local agricultural sector.
The project is structured under the Volumetric Water Benefit Accounting (VWBA 2.0) framework, allowing rigorous quantification of the water benefits generated, their digital traceability, and integration into corporate water replenishment reports in accordance with international standards.
The Níjar area is one of the most intensive agricultural hubs in Europe, characterized by high-density greenhouse horticulture. This production model depends almost exclusively on coastal aquifers such as Campo de Níjar and Bajo Andarax, which show alarming piezometric decline, with exploitation levels far exceeding natural recharge. The direct consequence has been seawater intrusion in coastal areas, jeopardizing the viability of agricultural wells and triggering resource access conflicts.
At the same time, the region’s sanitation infrastructure includes several wastewater treatment plants, such as Níjar, El Toyo, and San Isidro, with tertiary treatment capabilities. However, their reclaimed effluents are currently discharged into the sea or watercourses without agricultural reuse, despite meeting technical standards for irrigation. The total available volume is estimated to exceed 1.2 million m³ annually, representing a strategically underutilized alternative water source.
This imbalance between growing water demand and underused reclaimed resources presents a structural opportunity to implement circular water economy solutions. The project aims to reconnect this available surplus with agricultural needs, promoting both environmental and productive resilience, while enabling the achievement of corporate water replenishment targets within agro-industrial supply chains.
The proposed solution involves implementing a comprehensive reclaimed water reuse system for agricultural purposes, integrating technologies for capture, advanced treatment, storage, and pressurized distribution. The system will draw from tertiary-treated effluents at wastewater treatment plants that consistently meet irrigation quality standards (e.g., EC < 2.5 dS/m, total coliforms < 1000 CFU/100ml). These volumes will be stored in covered regulation ponds to minimize evaporative losses and distributed through a pressurized hydraulic network to agricultural plots selected based on agronomic eligibility and strategic location within the irrigation system.
The infrastructure will include advanced polishing stations equipped with safety filtration (100–200 micron mesh), ultraviolet disinfection (with automatic dosing and effective dose monitoring), and multiparametric sensors to monitor turbidity, EC, pH, and residual chlorine. The system will also feature automatic valves, high-precision flow meters, and pressure sensors at delivery points, all integrated into a georeferenced digital monitoring platform.
The selection of beneficiary farmers will be carried out in coordination with local irrigation communities (CR Níjar Norte and CR San Isidro), prioritizing farms using localized irrigation and willing to replace groundwater with reclaimed water. The operational model will be governed by formal usage agreements and monitoring plans that allow for traceable and certified volumetric water benefits under the VWBA 2.0 standard, supported by the Aqua Positive platform.
The project will be implemented through a structured technical sequence ranging from initial validation of available resources to the sustained operation of the system, integrating planning, construction, and monitoring activities.
First, a technical diagnostic and institutional agreements phase will be developed, lasting approximately three months. This stage involves exhaustive characterization of the tertiary-treated effluents from the El Toyo, Níjar, and San Isidro Wastewater Treatment Plants through analyses of key parameters such as electrical conductivity, coliforms, turbidity, and nutrient load, in order to confirm their suitability for agricultural irrigation under the criteria established by Royal Decree 1620/2007. Simultaneously, a georeferenced mapping of agricultural plots surrounding the treatment plants will be carried out to identify those with the highest technical viability and willingness to be integrated into the reclaimed water irrigation system. This process will also include formal collaboration agreements with irrigation communities such as CR San Isidro and CR Níjar Norte, wastewater treatment plants operators, and local authorities.
Based on the prior diagnosis, the technical design and feasibility studies phase will take place between months 3 and 6. This stage includes hydraulic modeling of the distribution network, definition of operating pressures, sizing of regulation ponds and polishing stations, and integration of control nodes with multiparametric sensors and a telemetry platform. A simplified environmental impact study will also be drafted, if applicable, and permits will be processed before the Andalusian Government. Technical calculations will consider variables such as design flow, head loss, usable storage volume, and retention time, aiming to maximize the system’s operational efficiency.
The execution and installation phase, projected between months 6 and 12, involves the construction and physical implementation of the system. It includes installing the hydraulic distribution network with high-density polyethylene pipes, constructing regulation ponds with floating covers, and installing pumping stations and technical huts equipped with final treatment systems (120-micron mesh filtration and ultraviolet disinfection). A continuous monitoring system will also be implemented to record real-time data on conductivity, turbidity, residual chlorine, and coliforms. Pressure tests, sensor calibration, and functional validation will be carried out on selected pilot plots to assess the system’s hydraulic efficiency and the delivered water quality.
Finally, from month 12 onward, the operation, monitoring, and scaling phase will begin. This stage will include the deployment of a digitized system for registering and tracing distributed volumes, irrigated hectares, and delivered water quality parameters, integrating this information into a database available for external audits and reporting. Annual performance audits will be conducted under the VWBA 2.0 methodology, validating the volumetric water benefits generated (additionality, permanence, traceability), and preparing reports aligned with international frameworks such as CDP Water Disclosure, ESRS E3, and Act4Water. This phase also envisions the progressive expansion of the system to new agricultural users within the wastewater treatment plants service area, prioritizing farms capable of replacing groundwater abstraction with reclaimed water in a safe and sustainable manner.
This project offers a structural solution to the severe water crisis affecting Campo de Níjar, one of the driest regions in Europe and highly dependent on intensive greenhouse agriculture. By reclaiming water from urban wastewater treatment plants (El Toyo, Níjar, and San Isidro), the project proposes a circular water management model to replace current groundwater extractions with the safe and controlled use of reclaimed water for agricultural irrigation.
The project is designed to capture, refine, store, and distribute reclaimed water through a pressurized hydraulic network to agricultural plots managed by local irrigation communities. It includes the installation of regulation ponds, pumping stations, final filtration, ultraviolet disinfection, and an online monitoring system that controls parameters such as electrical conductivity, turbidity, residual chlorine, and coliforms.
The project will be developed in four phases: diagnosis and institutional agreements, hydraulic system design and permitting, infrastructure installation, and monitoring and scaling. It is expected to replace over 100,000 m³/year of groundwater abstraction with reclaimed water, reducing pressure on critically stressed aquifers such as Campo de Níjar and Bajo Andarax. Additionally, it strengthens the resilience of the agricultural sector, ensures irrigation reliability, promotes circular practices, and aligns water benefits with international frameworks such as CDP Water Disclosure, ESRS E3, Science-Based Targets for Water, and Act4Water.
The project directly supports SDGs 2, 6, 12, 13, 15, and 17. All systems will be integrated into a digital traceability platform, ensuring transparency, additionality, and permanence of the benefits. In this way, the project proposes a real and measurable transformation of the local water management model, adapted to the climate conditions of southeastern Spain and replicable in other water-stressed regions.
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