Espronceda, her turbulent romance with Teresa and technologies to take advantage of every last drop

The engineer of the Almendralejo WWTP Andrés Cid points out the ultraviolet light reactor to purify the activated carbon in the 'Project Ô' laboratory on September 1. PACO PUENTES

The romantic José de Espronceda could hardly imagine that, 214 years after his birth, his origins and his work had a link with one of the biggest problems in Spain, drought, and a technological innovation that can alleviate water scarcity.

But such is chance.

The City Council of Almendralejo (Badajoz), based in the poet's birthplace, and the water service concessionaire company, Socamex, are part of an EU research plan, called

, to create formulas to increase water resources.

The Spanish laboratory develops a system to reuse the wastewater generated by its 33,400 inhabitants, companies and fields to give them a new opportunity in street cleaning, parks, irrigation and industrial uses.

The experiment has luminescent bacteria that act as sentinels and regenerative ultraviolet lights of activated carbon to add one more link to the water cycle and reuse part of the eight million liters purified each day.

Espronceda described the water cycle.

It wasn't his intention.

His song

the extraordinary poem he wrote around 1839, resorts in a stanza to an allegory to refer to one of the phases of the turbulent love between the writer and the daughter of Colonel Epifanio Mancha:

And they finally arrived… Oh!

Who wicked / woe!

withered the flower of your purity?

/ You were once a crystalline river, / spring of pure cleanliness;

/ then a somber-colored torrent, / breaking between rocks and undergrowth, / and a pool, finally, of corrupted waters, / stopped between fetid mud

The answer to Espronceda's question, if isolated from the context of her love, is the population, the industry and the fields, which turn, with the use of water, "the spring of pure cleanliness" into a "torrent of dark color" .

This finally reaches the "pond, in short, of detained waters between fetid mud", the wastewater treatment plant (WWTP) of Almendralejo.

And here begins the

, which has 23 partners from 10 countries.

In the Almendralejo laboratory, according to the manager of Socamex, Francisco José Obreo, one of the lines of action is the development of an "advanced pollution control" system.

The wastewater reaches a biological bed, where its treatment begins.

But if any of the "ungodly" alters the conditions of these waters with polluting elements for which the system is not prepared, "it can attack the biological bed and disable the plant."

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The advanced control system uses luminescent bacteria developed in Israel and initially intended as defense systems.

"If, for example, the water has greater conductivity due to the presence of salts [brine is a common waste from the local agri-food industry], the bacteria light up and that water is diverted to a special tank," explains Andrés Cid, WWTP engineer.

Obreo highlights that this system saves maintenance costs of conventional sensors and avoids depending on technologies that, in case of failure, can take months to be replaced or repaired.

The second system is an activated carbon tank that reduces contamination and turbidity in the water.

The carbon generates links that retain the contaminating particles.

But it has a limited capacity and becomes saturated.

That is where the other element of the technology used by the Almendralejo laboratory comes in.

The water with the coal passes through a reactor of ultraviolet LED (light emitting diode) lights to clean the mineral that, once filtered and decanted, is operational again.

Activated carbon purification tank (right) and ultraviolet light cleaning reactor (left) installed in the Almendralejo WWTP laboratory. Paco Puentes

“Until now”, explains Cid, “this activated carbon cleaning process, which comes mainly from China and is expensive, was done in a few places and using ovens.

If we manage to increase the useful life cycles of the material, costs can be reduced by up to 40%”.

The water treated with this system would allow a large part of the treated wastewater to be reused by ensuring that its parameters are compatible with the regulations for agricultural, industrial or urban uses (flushing and irrigation of gardens).

Obreo explains that not all of the 8,000 cubic meters per day could be reused, because a part must be reintegrated into the ecological flows of the hydrographic systems, but he believes that, under optimal conditions, up to 80% of the water that reaches the the WWTP.

Why Almendralejo?

Espronceda's influence is accidental, because he was born in what is now the seat of the City Council, where the project was conceived, and because of the opportune stanza of his work.

But the motivations were different.

Antolín Trigo, Councilor for Urban Planning and head of the water service, explains that the area is dry and highly affected by the drought.

“It is very difficult to find water,” he laments.

Despite this deficiency, the thriving agricultural industry (vine and table olives, mainly) demands more every day.

One of the tanks of the Almendralejo wastewater treatment plant (WWTP), PACO PUENTES

“The concessionaire [Socamex] made us the proposal to submit to the European program and we considered that it was very important to regenerate a basic resource, and more so in times of drought and in an agricultural and urban area.

We had the right conditions and a recent WWTP, built in 2014 after an investment of 14 million euros.

We are trying to evolve”, explains the mayor.

The European project has 10 million euros, of which 10% has been used in the first phase of gestation, laboratory and testing.

But this system is only tested for a daily flow of 20 cubic meters and the final results will be at the end of the year or at the beginning of the next.

From there, a new critical phase will be passed: scaling the model to apply it to the flows of medium-sized cities such as Almendralejo and, if all goes well, to any WWTP.

The use of residual recycled water is restricted for human consumption, for safety reasons and as long as there is a sufficient supply of drinking water, according to Royal Decree 1620/2007.

However, it is allowed to use it for purposes that admit quality limits lower than that required for drinking, such as irrigation and cleaning of urban environments.

However, Fernando Morcillo, president of the Spanish Association for Water Supply and Sanitation (AEAS), considers that "it is cheaper to produce drinking water from wastewater than to make seawater drinkable," he told Efe.

Andrés Sánchez Yagüe, head of the Communication Committee of the Spanish Digestive System Foundation (FEAD) adds: "Any water is suitable for drinking if you are certain that the treatment process is safe."

The municipality of Almendralejo is not alone in the

.

Puglia (Italy), Eliat (Israel) and Omis (Croatia) are testing other systems.

Giulia Molinari, former manager of the program explains: “We are trying to use many different technologies on a small and medium scale to adapt the quality to the needs of each use.

Not all treated water needs to be potable.

Laboratory of the 'Project Ô' in Almendralejo.PACO PUENTES

In Puglia, a module is being tested that integrates a desalination plant and advanced oxidation techniques using high-voltage electromagnetic pulses to eliminate microbes and break down contaminants.

In a textile factory in Croatia, a system has been developed that uses sunlight to remove toxic organic compounds and disinfect water.

In Israel, the laboratory recovers nutrients from salt water.

Both the

and the so-called

seek to treat water and reuse it in places where unique solutions are required.

Hydrousa

is being tested on three Greek islands.

“It is about tackling the problems of water scarcity in remote, small, decentralized regions of the Mediterranean,” Simos Malamis, a specialist in water systems at the National Technical University of Athens, explains to

, the EU's research and innovation magazine. (Greece) and program coordinator.

The objective, as he explains, is to "double its rate of use of circular material in the next decade", which implies identifying the value of products that have traditionally been considered waste, such as phosphorus or salts.

Biogas recovery module (right) and silos for the reuse of already treated sludge (left) at the Almendralejo WWTP. Paco Puentes

The Greek project has many similarities with the Spanish.

In Lesbos, they also use a biological bed to purify the biogas generated (as in Almendralejo) and an artificial wetland that acts as a complementary filter.

The resulting water is exposed to high-energy ultraviolet light to kill pathogens and delivered to farmers, Malamis explains.

In parallel, in Mykonos,

technologies harvest and store rainwater underground, so that the water does not evaporate, and is then distributed to households.

On the island of Tinos, an ecotourism lodge recycles wastewater and rainwater to irrigate and fertilize food gardens that feed tourists and residents of the nearby town.

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