Managing drinking water and sewage treatment is a major challenge for many tourist resorts around the world. How does municipal drinking water and sewage treatment in Almuñécar – La Herradura work?
Text: Rolf Bönström Hedberg
The importance of access to water even the Romans knew since they built the aqueducts to Almuñécar. However, when the Romans were pushed out by the Western Goths in the early 400s, much of this infrastructure fell into disrepair due to lack of maintenance. When the Moors took power in most of Spain in the early 700s, there was severe drought and crop failure in the country.
The Moors not only repaired but also expanded the water supply to be able to grow the soil with better and several harvests per year. Tunnels and covered waterways were also built to reduce evaporation. Special water tribunals were established where elected members of the farmers decided how the water would be distributed. Such a tribunal still exists in Valencia – over a thousand years later!
Parts of the aqueducts in Almuñécar are still in use today, today they are now supplemented with new wells (Pozos) in the river valleys. The Rio Verde and Rio Seco rivers also exist today, but mostly the water flows 30 – 40 meters below ground level.
Closer to the coast and in Almuñécar, however, the water flows much closer to the surface. Several newly built garages and parking spaces under Paseo del Altillo and San Cristobal therefore have bilge pumps that continuously keep the water level below the floor surface. There is a thought that this “fresh water” could be returned to the ground for irrigation a few kilometers upstream instead of just pumping it out into the sea, but it costs…
Due to the uneven availability of water here in southern Spain, large water reservoirs are required to ensure the water supply all year round. In the mid-1980s, after the very dry summer of 1983, there was a project to build a dam in Rio Verde. But, like many projects, none of it happened.
The larger dams in use in the vicinity of Almuñécar are Beznar (56 hm3, completed in 1935) and Rules (111 hm3, completed in 2004). The water in both dams comes from the Sierra Nevada mainly via Rio Guadalfeo. Rules was built as a water reservoir for agriculture that consumes about 70 % of all fresh water. However, almost 17 years after completion, the fitting of water pipes to supply the growers with water has not begun. Like many large projects, the budget was already consumed, and the money was not enough. Today the dam is probably the world’s most expensive windsurfing pool!
However, the water from the Sierra Nevada that has ended up in the Rules dam is used today for drinking water. Pipes from the dam go to a water works (=una potabilizadora) in Molvizar. It treats the water to become municipal drinking water in Almuñécar – La Herradura. The water is filtered, purified from organic matter and microorganisms and added chlorine. The water is quality assured by daily water analysis and then led in pipes via Salobreña, out into the sea to Playa Cabria and on to Almuñécar and La Herradura. The water capacity is normally about 80 litres/second (which means 6.9 million litres/day! Max 200 litres/second) and is sized for up to 220,000 people.
As late as the 1950s, latrine etc. was left at the riverside of Rio Verde, roughly below today’s Centro de salud in Almuñécar. One can only imagine how it smelled and how well fed that earth became! In 1970, a town network for the sewer was completed with a pipe that went straight into the Mediterranean, similar to the solution that Nerja still has!!! More about Nerja’s lack of sewage treatment plants can be found here…
The existing Almuñécar treatment plant was put into operation in 2004. The treatment plant was built with 60% funding from the EU, the rest has been paid through the water bills.
All municipal sewage in Almuñécar is linked to a common pumping station located next to the bridge over the Rio Verde (at las Gondolas). From here, the water is pumped to the treatment plant, which is about 1 km up, along the Rio Verde. The Almuñécar water treatment plant = la Depuradora (EDAR: Estaciones Depuradoras de Aguas Residuales) handles 1400 m3 of wastewater/hour and is one of six treatment plants on the Costa Tropical. La Herradura has its own wastewater treatment plant.
The treatment of wastewater takes place in several stages to filter out solid particles, microorganisms, sand, fats and organic waste. Organic waste is dried and used as fertilizer in the agriculture*
The purified water is analyzed daily by three independent parties: internally, externally and by the Junta de Andalusia. The purified water runs in pipes, via Rio Verde, one kilometer out into the sea and flows out at a depth of 50 m. 6000 m3/day, and up to 8000 m3/day in summer.
95 % of all wastewater in Almuñécar is treated through the municipal treatment plant. Small villages and single country houses are not connected to the treatment plant. However, there are requirements that these should also have approved private sewage systems, e.g. three-chamber well with biological filter
* Regarding the use of residues from treatment plants as fertilizer
In Sweden, the government investigation “Non-toxic and circular recirculation of phosphorus from sewage sludge” has been submitted to the government in early 2020. The study proposes a ban on the spread of sewage sludge and, as an alternative, exemption for the spread of good quality agricultural land.
Nerja’s lack of wastewater treatment plants
have so far cost their taxpayers EUR 4.37 million in fines to the EU! Construction of a treatment plant in Nerja began in 2014. Since then, it has suffered from recurring problems and delays. Now the construction is said to be completed, but electrical installations are still missing. Until these are in place, the treatment plant cannot be tested. Operational start-up can hopefully take place before the end of 2021.