poster - International Conference of Agricultural Engineering

In this way, the use of purified water, presents some problems:
1. Urban water derived to the water treatment plants suffers a quality loss since such
treated volumes become partially saline in the wastewater treatment plant of
Villajoyosa and mainly, in the Benidorm facility.
2. The treated water volumes are uniformly distributed along the year. However,
agriculture water consumption does not follow such tendency. Mediterranean climate
conditions set higher demand in summer months.
3. The treated water volumes have to be carried to the agricultural areas satisfying the
flow and pressure irrigation conditions.
2.2. Improvements in the irrigation water management
The previous issues have involved the search for a set of solutions that may or may not yet
be implemented.
As far as the issue of the water quality, the wastewater facility of Benidorm has improved the
salinization problems with the installation of ultrafiltration equipment (Office of Water
Programs, 2006). The reverse osmosis system reduces water salinity from 3800 ⁄ to
1000⁄ .
The maximum daily treated volume is estimated in 21,000 m 3 when both the water rejection
and the total capacity of the facility are taken into account. Thereby, the annual usable
irrigation water can be determined straightforward resulting in a total volume of 7.5 hm 3 /year.
It can be observed that such volume means around half of the total capacity installed at the
Benidorm wastewater plant. Globally, the water treated in the three plants achieves a total
volume of 11 hm 3 /year. If the annual consumption rate of the irrigation crops is 5,000 m 3 /hayear,
it can be stated that the reuse of water is able to satisfy the irrigation needs of around
2,200 ha.
With regard to the non-uniformity of the irrigation water demand, the previous irrigation area
is estimated in 2,200 ha, but, it is not really true since it can be defined as the potential
irrigation area. As the supply of treated water does not fit the irrigation demand, the real area
will be lower. The maximum irrigation needs can be estimated in 35 m 3 /ha-day. Since the
daily autonomy of the wastewater plants reaches 31,000 m 3 , the real irrigation area results in
900 ha.
Then, farmers in the area are facing a critical situation during dry seasons that are very
common in semi-arid regions. The problem can be solved by means of the design and
construction of a reservoir, so water can be stored during low irrigation demand seasons.
Later on, water will be available in times of high consumption.
In brief, the following works and installations are needed in order to incorporate wastewater
for irrigation:
1. Implementation of ultrafiltration and desalination technologies to be applied into the
present purified wastewater.
2. Implementation of reservoirs with a storage capacity greater than 1 hectometre. Fig. 3
shows an overview of the Alfondons reservoir (Capacity = 300,000 m 3 ) storing the
purified water from the Villajoyosa wastewater treatment plant.
3. Implementation and construction of water regulation tanks.
4. Implementation of pipelines driving wastewater from the treatment plants to the
irrigation agricultural areas.
Nowadays, public administration is performing the following works.
1. An ultrafiltration and desalination plant is being built with a daily capacity of 21,000
m 3 /day, so the annual maximum autonomy reaches 7.7 hm 3 /year.
2. The main water line conducts treated wastewater through a ductile cast iron pipe of
900 mm diameter and 25 kilometres length, Fig. 4.