Lanzarote cannot treat all the wastewater it produces before dumping it into the sea

The island has 44 wastewater discharge points from land to the sea. Of these, three quarters (75%) are irregular.

February 19 2024 (19:54 WET)
Updated in February 20 2024 (12:41 WET)
Water discharge into the sea in the area of the Royal Yacht Club in Arrecife
Water discharge into the sea in the area of the Royal Yacht Club in Arrecife

What happens to wastewater once we press the toilet flush button becomes a handicap for the preservation and care of the environment. The situation is further aggravated when dealing with island territories with a specific extension and that see how their coastlines are being affected by discharges into the sea. 

Lanzarote, an island with 163,543 inhabitants and three million tourists a year, has 44 wastewater discharge points from land to the sea, according to the census prepared by Servicios Omicron SA at the request of the Ministry of Ecological Transition and Energy of the Government of the Canary Islands.

Of these, three quarters (75%) are irregular and in 65.9% of cases they function as overflows when the sewage networks need it. Thus, by their nature, more than half of these discharges are urban (63.6%), which are concentrated in Tías (12 points), Arrecife (seven), Teguise (six), San Bartolomé (two) and Yaiza (one). It should be noted that the census does not record urban discharge points in Tinajo or Haría. 

In this line, brine spills, produced by the desalination of water and the disposal of the surplus to the sea, are present in five places on the island. In particular, they are concentrated in Arrecife (two), Yaiza (two) and Tías (one). 

The inventoried industrial discharges are in four points of the capital of Lanzarote. Thus, the category of others registers mixed effluents, where urban and industrial discharges and domestic discharges are combined. 

How discharges are eliminated

Of the different discharge systems, the drainage pipe stands out, which is used in 88.6% of the cases and in up to 39 points on the island. Among them, the majority are located in Tías (14), Arrecife (14) and Teguise (seven), while the rest are in San Bartolomé (two) and Yaiza (two).

Of these pipes, 25% are submarine. Specifically, this breakdown highlights the discharges in Costa Teguise, where 71.4% of the drainage pipes end up in the sea. 

For its part, the Inventory of Discharges of Lanzarote records four submarine outfalls or pipes that carry water from the Wastewater Treatment Plants to the sea. In this case, there are four points distributed in Arrecife (two), Tías (one) and Yaiza (one). While according to this report, wells only account for one of the island's discharges in Yaiza. 

The sewage of the population and tourism

The population centers of Arrecife and Tías, where "the highest values" of inhabitants are concentrated, also suffer a greater presence of wastewater discharges. At the same time, the sewage discharges in Yaiza and Teguise come from the tourist centers of Costa Teguise and Playa Blanca. 

Arrecife concentrates the only industrial area of Lanzarote where "direct discharges to the sea are generated". Specifically, the Unelco plant generates a discharge with a "quite abundant" flow and the Punta de los Vientos desalination plant of Inalsa emits brine "directly on the intertidal zone". 

The waters of the Arrecife sewage network are directed by the successive pumping stations to the EBAR Portugal. While in Playa Honda there is a sewage network with two pumping stations that drive the water to the EBAR and then to the Arrecife WWTP. 

The Inventory of Discharges of Lanzarote shows that there is "a concentration of urban discharges in large evacuation currents". While it highlights that the wastewater that is discharged into the outfalls of Puerto Naos, Puerto del Carmen and Costa Papagayo "cannot effectively treat all the flow they receive" because the plants that treat that water before dumping it into the sea are "undersized". 

Desalination of water

The lack of water on the island has led to the rise of desalination of water from the sea. The aforementioned report highlights that there is "a high number" of public and private desalination plants in Lanzarote.

In this case, it highlights that small desalination plants are usually located in hotels and tourist complexes that allocate the water to their own supply. In this line, the investigation concludes that the number of inventoried brine discharges should be "limited, because most of the discharges from small plants are usually made directly to the subsoil".

While on the centers of desalinated water production for public use, the research highlights the production located in Punta de los Vientos of Arrecife, the most powerful of the island with capacity for 45,000 cubic meters and the center of Janubio in Yaiza, with a daily production of 4,800 cubic meters.  

Sanitation and purification

On sanitation, most of the urban centers of Lanzarote already have a sewage network. Among them, Arrecife, the town of San Bartolomé, Playa Honda, Tías and Puerto del Carmen, Puerto Calero, Playa Blanca, La Santa Sport, Caleta de Famara, Famara, the town of Haría, Máguez or Costa Teguise already collect their wastewater and send it to treatment plants. However, the rest are eliminated through septic tank with filtering well or, mostly, with black well. 

Thus, the report reveals that the Wastewater Treatment Plant of Tías presents "greater problems of undersizing" because although it has capacity for 3,000 cubic meters of wastewater per day, it receives about 6,000. For this reason, "in large part they must be diverted directly to the submarine outfall of Puerto del Carmen without undergoing adequate treatment". 

To solve this situation, the expansion of this treatment plant is underway, as well as those of Arrecife and Haría and the construction of a new plant in Playa Blanca. 

Faced with these discharges, there is the reuse of water once treated. In the case of Costa Teguise, for example, all the water that is treated is reused. While in Tías, Arrecife and Playa Blanca this water is also used to irrigate the green areas. 

La Graciosa and the Chinijo Archipelago

The distillation plant located in La Graciosa and with capacity for 75 cubic meters per day has been stopped for five years. The same happens with the Lanzarote II Plant located in Punta de los Vientos. Neither has been considered for this inventory. 

 

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