Wednesday, November 21, 2018 - 14:57
In October, one of the most active IWAMA partners Estonian Water Works Association organised a study visit to Madrid, Spain to exchange knowledge, experiences and good practices with colleagues beyond the Baltic Sea Region.
The purpose of the study tour was to exchange expertise with peers by visiting the local water operators, local umbrella organization of water companies (AEAS – Spanish Water and Wastewater Association), and the Ministry of Agriculture, Food and Environment responsible for the water sector (supervising agriculture, food hygiene and environment).
It was very much in partner´s interest to see how the European Union regulations are implemented in the country that has significantly warmer and drier climate compared to Estonia. Climate change, reuse of wastewater, and water treatment in the conditions where freshwater resources are limited were among the most discussed topics. Meeting with the AEAS – Spanish Water and Wastewater Association and the representatives from the Ministry of Agriculture, Food and Environment provided very valuable insights into national policy framework and lifelong learning programs provided by the Spanish water companies.
Facts about the water management in Spain
- Sources of water supply – 67% surface water, 28% groundwater and 5% desalination of seawater.
- Sources of all the water used, incl. by industries and agriculture – 80% surface water and 20% groundwater.
- Challenges with financing: EU co-financing ending in 2020.
- Pressure by the European Commission to increase the water tariff.
- Many various tariffs – for ordinary citizens, poorer population, large families, etc.
- Significantly higher tariffs for industries. For instance, while the normal tariff for ordinary citizens is ca 1.8 EUR/m3, the industries must pay 2.8 EUR/m3 (average tariff in Spain).
- Maximum State aid rates have not been an obstacle since larger investments were implemented before the State aid rules were introduced.
- Tariffs are established by the local municipality government.
- Water is reused. Upstream settlements use water from the river to produce drinking water, discharging the effluent back to the river. The same circulation is used in the downstream settlements, however, with each circle, the river becomes more and more polluted and the treatment more expensive.
- According to Ministry of Agriculture, Food and Environment, the most important in the water management is to ensure the good quality of drinking water.
- 60% of sewage sludge is used in agriculture, ca 16% is incinerated, and the rest of the sludge is used in other areas, such as to produce construction materials.
- As a rule, the assets of the water companies are owned by the local municipalities or municipality-owned water companies. Assets can be operated by the municipality-owned companies, private companies, as well as by the PPP companies.
- Drinking water consumption per capita is ca 240 l/day.
Practical observations at the wastewater treatment Plant in Arroyo Cuebro
Capacity of the WWTP in Arroyo Cuebro is 1.2 mln PE. The plant provides services to ca 0.5 mln inhabitants in Madrid area. The limit values for effluent discharged to River Manzanares are:
- 1.0 mg/l for phosphorus (P)
- 15 mg/l for nitrogen (N)
Reclaimed water is used for washing the streets and for irrigation purposes – for this, the wastewater that has been through the treatment process, undergoes additional UV-treatment. Tariff for the irrigation water given to the City forms 10% from the drinking water tariff.
Reclaimed wastewater supplied to the industry (a nearby paper mill) is undergoing the traditional wastewater treatment process, and is additionally treated by means of carbon filtering and reverse osmosis, as a result of which the wastewater achieves characteristics similar to those of distilled water. Tariff for distilled water supplied to the paper mill is the same as the tariff for drinking water supplied to industries.
The most recent investment at the plant costed ca 46 mln EUR. The investment was fully funded by the water company and the local municipality, without any co-financing from the EU.
In a normal situation, the WWTP in Arroyo Cuebro is operating using 50% of its capacity. When the incoming flow begins to exceed the capacity of the plant, the additional flow is directed to another wastewater treatment plant located nearby. 60% of sewage sludge is composted and the rest of the sludge, usually containing high concentrations of heavy metals, is used in producing cement.
Reclaimed water is used for watering gardens and parks during summer months only.
Water Treatment Plant in Sant Joan Despí, Barcelona
3-4% of water demand is covered from the seawater distillation, rather used as a possibility to ensure the reliability of drinking water supply. The rest of the drinking water is drawn from the boreholes in the area. The water treatment plant gets its raw water pumped from the nearby river EI Llobregat.
The river is quite polluted because of the upstream industrial area discharging pollutants to the river, such as zinc and cadmium. Further, the river water is salty because of the upstream salt mine. Ca 50% of Barcelona’s water demand is covered from the water treated at Plant Sant Joan Despí.
Stormwater Retention Tank in Arroyofresno
Built to collect stormwater from the streets of Madrid area into one single tank, in order to reduce the pollution caused to river Manzanares running through Madrid.
The stormwater tank can be classified as a retention tank for the local wastewater treatment plant because most of the stormwater collected to the tank will pass the wastewater treatment process later on. Usually, the tank is only filled to a small part.
Construction was started in 2005 and completed in 2009. Since it was completed, the tank has been completely full on three occasions only, last time in March 2018. Tanks are normally cleaned 2 times a year. The tank has an overflow to river Manzanares, which has never been used.
Some basic figures about the tank dimensions:
- tank capacity – 400,000 m3
- excavated soil – 1 mln m3
- constructed using 185,000 m3 of concrete
- consisting of 500 pillars
- length – 9,600 m
During the study visit, partners also learned about the Control Centre of Canal de Isabel II in Majadahonda, Control Centre and water lab of AGBAR (Water Company of Barcelona) and Roman Aqueduct in Segovia. For more detailed information on specific sites, please read the study tour summary.
