
Water reclaimed for irrigation from the Castellon wastewater treatment plant
4 June, 2050

Waste water source
The reclaimed water originates from the Castellón wastewater treatment plant. There are some problems with high salinity (3 g/l) and boron toxicity in the effluent. The water is therefore mixed with surface water for agricultural application.
Distribution System
The reclaimed water is mixed with surface water in a water pool close to the wastewater treatment plant. Then it is transported by an irrigation network to the local stations where nutrients are added according to the set recipes. A fertigation network distributes the nutrient solution to the fields.
Farming system
The irrigated fields are mostly citrus trees. The irrigation community commonly applies fertigation.
Waste water treatment description
Nutrient removal : Conventional wwtp techniques (activated sludge...)
Pesticide removal : none
Disinfection : UV disinfection
Suspended solids removal : In primary treatment physical sieves are used, later chemical coagulation and filtration
Other :
Capacity
The wastewater treatment plant’s production corresponds to 40,000 m³/day. The irrigation community uses 10,000 m³/day on average.
Extent of the agricultural beneficiaries
2,000 hectares are irrigated with the reclaimed water, divided over approximately 2,000 farms
Costs
They pay only the costs that they had for surface water. The operation and maintenance costs are over 0.02 €/m³.
Type of agreement
The irrigators community has a cost swap between the city council and the irrigators community. It is due farmers raise their water concession and use of high quality surface water to the city council, and farmers receive water from the reclaimed water facility without extra cost. Farmers only pay the costs that they had for surface water.