Water and agricultural research platform

Low-cost water desalination and sensor technology compact module - DESERT

Waste water source

ESAMUR is the public sanitation agency in charge of wastewater management and CADAGUA is the subcontractor responsible for conducting the water reclamation tasks. Treated wastewater effluent has an urban origin and is mainly coming from small towns and golf courses in the area. The following are some of the influent characteristics:  pH: 7.9; EC: 1.39 dS/m; Na: 169.7 mg/L; K: 28.6 mg/L; Ca: 70.2 mg/L; Mg 26.1 mg/L; NH₄: 3.7 mg/L; Cl: 206.6 mg/L; SO₄: 149.3 mg/L; CO₃: 0,0 mg/L; HCO₃: 301.8 mg/L; NO₃: 9.7 mg/L; PO₄: 2.9 mg/L.

Distribution System

The Irrigation District of Campo de Cartagena (founded in 1952) has several sources of irrigation water (amounting to a total flow of 142 hm³/year), including reclaimed water (13.5 hm³/year) produced from the effluents of 7 wastewater treatment plants. The main features of the Irrigation District of Campo de Cartagena are: a main irrigation channel of 64 km; a maximum flow of 25 m³/s; 778 km of service roads; 7,106 water outlets; 1,033 km of pipes (ranging in diameter from 1,600 mm to 80 mm); 9 pumping stations; 957 remote stations; and a storage capacity of 2.1 hm³.

Farming system

Treated effluent from the Roldán-Balsicas wastewater treatment plant is reclaimed using a prototype module and then used for agricultural irrigation by the Irrigation District of Campo de Cartagena. Cultivation techniques include horticultural crops (59 %), citrus trees (30 %), fruit trees (4 %) and greenhouses (7 %). Greenhouses cover about 1,300 ha of irrigated land, with about 96 % of that surface devoted to pepper cultivation; the rest is devoted to cultivation of zucchini, tomato and ornamental flowers. Cultivation is mainly (93 %) conducted using drip irrigation techniques.

Costs

The cost of irrigation water is 0.35 €/m³.

Type of agreement

Farmers pay for irrigation water in proportion to the land surface they irrigate, using the average cost of a mixture of 4 different water supply sources. Furthermore, they are legally required to cover the costs of the analytical monitoring of reclaimed water quality.

Scientific results

Intriago, J.C., Lopez-Galvez, F., Allende, A., Vivaldi, G.A., Camposeo, S., Nicolás, E., Alarcón, J.J., Pedrero Salcedo, F. (2018). Agricultural reuse of municipal wastewater through an integral water reclamation management. Journal of Environmental Management 213; 135-141.

The DESERT prototype served to demonstrate the agronomic viability of the water treatment process. The safety of the reclaimed water produced by the DESERT prototype was demonstrated under different scenarios (drip and sprinkler irrigation) using lettuce as one of the crops most vulnerable to microbial contamination. The study showed the absence of pathogens. A deterministic and stochastic manager-oriented QMRA model showed negligible risks of infection in all DESERT water exposure scenarios. The DESERT team was fully aware that public acceptance is a crucial factor for succeeding in using reclaimed water for agricultural irrigation and that risk acceptance rely on factors that are beyond simple risk estimations, such an appropriate risk communication and management. Water quality levels, agronomical quality of crops, and health risk assessments have shown that the DESERT prototype stands out as an appropriate add-on technology for safe water reclamation. The DESERT prototype was able to respond effectively to the main environmental/agricultural and public health concerns posed by reclaimed water use, namely salinity and pathogenicity, respectively. Furthermore, the multiple-barrier approach and the post-harvest strategies, with the irrigation technique being of uppermost importance, support and complement the DESERT reclamation technology in reaching the safety targets, thus preventing recontamination and cross-contamination of produce during the whole farm-to-fork cycle.

Additional information