Integrated Water Reclamation and Reuse (IWRR) Management Plan of Vitoria-Gasteiz
4 June, 2050
Irrigation with reclaimed water at Vitoria-Gasteiz
Waste water source
The Delfín Water Reclamation facility (entrusted to the Arrato Irrigation District) receives biological secondary effluent produced by the nearby wastewater treatment facility of the city of Vitoria-Gasteiz. Vitoria-Gasteiz, the capital of the Álava province and the headquarter of the Regional Government of the Basque Country, has a population of about 220,000 inhabitants and a very diverse industrial activity, which contributes about 30 % of its wastewater flows. The city shares its water supply system with the metropolitan area of Bilbao (1 million inhabitants) by the conjunctive use of the Zadorra River reservoirs, whose total useful capacity is 180 hm3.
The ultimate goal of Integrated Water Reclamation and Reuse Management Plan of Vitoria-Gasteiz was to store the reclaimed water produced during the fall-winter-spring period as to provide enough water for summer irrigation of 10,000 ha (3,300 ha effective). To reach that goal, a provision was included for constructing an off-stream reservoir, where the reclaimed water could be collected and stored during the non-irrigation season. Although the off-stream storage reservoir was completed in 2005, several technical deficiencies (still to be corrected) have postponed its entering into full operation so far.
The limited water resources available in the Vitoria-Gasteiz watersheds during the summer season severely limit agricultural irrigation of the surrounding fertile plains, at a time of the year when weather conditions resemble much to the nearby dry continental areas. The lack of local aquifers capable of storing winter precipitations has traditionally resulted in a strong competition for the highly regulated surface water flows assigned for drinking water supply to Bilbao and Vitoria-Gasteiz. Water rights for the Delfín Water Reclamation facility effluent were granted to the Arrato Irrigation District for irrigation during the summer season of 10,000 ha of several food crops, mostly processed vegetables (peas, beans and potatoes).
Waste water treatment description
Nutrient removal : Biological nitrogen removal (nitrification-denitrification) since 2006.
Pesticide removal : none
Disinfection : Combined chlorine disinfection.
Suspended solids removal : Coagulation-flocculation, plus ballasted lamella sedimentation and rapid sand filtration.
The Delfín Water Reclamation facility was completed in 1994 and has a flow capacity of 35,000 m3/day of high quality reclaimed water for unrestricted irrigation of all types of foods crops. That flow of reclaimed water represents about 50 % of the secondary effluent flow produced by the nearby municipal wastewater treatment plant during the summer season.
Extent of the agricultural beneficiaries
An irrigation pipe network was built to distribute the reclaimed water over 10,000 ha of irrigated land located on the plains surrounding Vitoria-Gasteiz. The reclaimed water flow was initially allocated for irrigation of 4,000 ha (1,300 ha effective each summer season, under a once-every-three-summers regime) by continuous operation of the reclamation facility during the summer season. Optimal yearly operation of the water reclamation facility was limited by the ability of the system to store the reclaimed water produced during the fall, winter and spring seasons. In 2005, an off-stream storage reservoir of 7 hm3 was built within the limits of the irrigation area, as to collect and store the reclaimed water flows produced during the non-irrigation season, so they could be subsequently used for irrigation during the summer season. However, several technical deficiencies were detected during the initial operation of the reservoir, preventing it from getting operational. That condition has kept the initial limit of 4,000 ha as the maximum surface area that can be currently irrigated with reclaimed water during the summer season.
The construction investment of the Delfín Water Reclamation facility, capable of producing 12.5 hm3/year, was 3.25 million euros that represents a unit investment of 0.26 €/m3 of annual production capacity (1995). The unit cost of reclaimed water at the facility site (capital plus O&M costs) was estimated at 0.065 €/m3 in 2006. The total investment required to convey, store and distribute 12.5 hm3 of annually produced reclaimed water was 28 million euros that represents a unit investment of 2.25 €/m3 of water annually produced.
Type of agreement
The Integrated Water Reclamation and Reuse Management Plan of Vitoria-Gasteiz was a publically funded initiative from the Álava province government. The three elements of the plan (a water reclamation facility, an irrigation pipe network and an off-stream storage reservoir) were subsequently delegated to the Arrato Irrigation District, who is responsible for its operation and maintenance while providing water for irrigation of 10,000 ha of farmland. Since its inception, the Arrato Irrigation District has been covering the investment costs and the operation and maintenance costs of the facilities.
Mujeriego, R. y López, J. (2008). Water reuse and integrated water resources management in Vitoria-Gasteiz, Spain. Water Practice and Technology, Vol. 3, Issue 2. International Water Association Publishing 2008. http://www.iwaponline.com/wpt/003/0048/0030048.pdf
Mujeriego, R., and López, J. (2006). The Azúa Valley Lake and integrated water resources in Vitoria-Gasteiz. Proceed. of the Intern. Symp. on Dams and Reservoirs, Societies and Environment in the 21st Century, Berga et al (eds), June 2006, Barcelona. Taylor and Francis Group, London, Vol. 1, pp. 117-124. ISBN; 0 415 40423 1.
Since 1991, water reclamation and reuse have become essential components of water resources management in Vitoria-Gasteiz, helping the city to overcome the historical water deficits traditionally experienced. The Integrated Water Reclamation and Reuse Management Plan of Vitoria-Gasteiz produces a reliable flow of 35,000 m3/day of high quality reclaimed water suitable for unrestricted irrigation of food crops, in accordance to California and Spanish regulations. The options available for integrated water resources management have widely expanded over the years, to include additional strategies such as stream water substitution, and more effective flood control protocols for the Urrunaga-Ullibarri reservoirs system. The Integrated Water Reclamation and Reuse Management Plan of Vitoria-Gasteiz was initially proposed and promoted (1994) by agricultural users and the Diputación Foral de Álava. Although water quality requirements were based on California regulations, in the absence of Spanish regulations at the time, the receptiveness of the Basque Country Public Health Service and all the users involved have greatly contributed to render water reclamation and reuse a common feature of water resources management in the area.
There have been no known or documented negative impacts or side-effects in the region (soil, users, and consumers) since irrigation of foods crops with reclaimed water was started on the Vitoria-Gasteiz plains in 1994. The microbiological water quality results available from 1996 to 2006 indicate a strict compliance with the requirements of absence of total coliforms (cfu/100 mL), helminth eggs, Giardia lamblia and Cryptosporidium (micro-organisms/500 mL), as well as of Legionella per liter, and of Salmonella per 100 mL.