A few days ago, the agreement between the president of the Cabildo of Tenerife, Rosa Dávila, and the Secretary of State for the Environment, Hugo Morán, was publicised, which will enable an increase of 233 million in the investment earmarked to complete the entire sanitation and wastewater treatment infrastructure on the Island. With this amendment to the agreement with the public company Acuaes, the total allocated for these processes will approach a figure near 400 million euros. It is widely acknowledged that this matter is, undoubtedly, one of the most pressing on the Island that necessitates an immediate resolution.
For the northern region of the Island, this funding will be allocated to finalising the sanitation system of the La Orotava Valley, which has reached a construction completion percentage of 92%; for the Acentejo treatment facility, once the absorption wells are constructed; for the second phase of the Puerto de la Cruz treatment plant; which will enhance water treatment capacity and thus meet the demands of the next 25 years; and for the regional treatment plant of Isla Baja, where, according to the Insular Water Council, work is already in progress to collect and regenerate wastewater for agricultural purposes. It is within this context that I would like to highlight a longstanding issue that demands at least a collective reflection to better understand the current circumstances.

Wastewater purification, a historical obligation with Isla Baja | ED
In 2017, the insular Water Council proposed a plan based on the directives of the insular Hydrological Plan, aimed at enhancing the sanitation and purification system on Isla Baja comprehensively and in two phases. This plan serves as a water infrastructure planning document designed to ensure that sanitation systems are regional, for reasons of economic efficiency and environmental compliance, with actions targeted at adhering to European water regulations. The Hydrological Plan is responsive to legal stipulations at European, regional, and island levels, and has been developed with the due involvement of citizens, institutions, and sectoral stakeholders.
The initial phase of the aforementioned sanitation system, presented in the Strategic Framework for Island Development (2018-2021), focused on upgrading the Garachico water purification facility along with its respective pumping station. Currently, construction of the pipeline between Garachico and Los Silos, directed towards the wastewater treatment station at the head of the Los Silos outfall, is in progress and is expected to be completed this year. Javier Davara, the manager of the Insular Water Council, asserts that these pipelines “currently comply with European regulations for towns with fewer than 10,000 inhabitants.” However, it must be noted that since last December, following 33 years, European regulations have become more stringent, thus, although during this transitional phase both municipalities are compliant, we must continue advancing the system to transition from adequate treatment to purification, which is the objective of the purification station.
Nevertheless, I wish to draw attention to the second phase of this system, which is the most significant, yet remains unresolved to this day. This pertains to the renowned regional treatment plant, with its site previously designated in the Ravelo pond area. This intensive purification facility would have the capacity to produce high-quality regenerated water, similar to other recently constructed sanitation and purification installations that will soon become operational, such as those in Guía de Isora, Granadilla, Güímar, or San Miguel. Existing purification and regeneration systems have been yielding very positive results for farmers, as seen in La Laguna, Tegueste, Tacoronte, or the tourist region of Adeje-Arona, which supplies purified water to farmers in the San Lorenzo Valley, among others. In these instances, discharges from treatment plants into the sea have been eradicated, except in emergencies, effectively addressing the significant issue regarding water supply for irrigation.

Wastewater purification, a historical obligation with Isla Baja | ED
At this juncture, we can deduce that while efforts are being made to resolve the situation in other areas to varying extents, time has been squandered in Isla Baja (Buenavista del Norte, Garachico, Los Silos, and El Tanque). Let’s examine the newspaper archives to dissect the situation so that you, discerning readers, may draw your own conclusions. The plans from the insular Water Council previously referenced have stagnated at the point when citizens, organised as a platform in conjunction with the municipalities of Buenavista and Los Silos, began to voice their discontent with the purification project and proposed an alternative treatment method they term natural, which has been applied, in the instance of Tenerife, in less populated regions such as Bolico, which serves around 500 residents.
The president and spokesperson for the Los Silos-Isla Baja Platform, Roberto Hernández, stated in 2021 that their organisation was endeavouring to halt the continuous discharge of wastewater into the sea via the Los Silos underwater outfall, accusing the island authorities and the Island Water Council of attempting to “confuse the populace” regarding the various purification models, advocating for a resolution that included establishing a purification plant with a Natural and Resilient Purification System on the Los Silos coast.
He then mentioned the initiation of two natural wastewater treatment plants featuring low energy consumption. The first would be situated on the coast of Los Silos, which would eliminate the need for the underwater outfall from the 1980s and initially manage the waters from Garachico; the second would be located on the Las Cruces coast, adjacent to the Garachiquense Wastewater Treatment and Pumping Station, “to prevent discharges into the sea and ensure that the waters from that municipality do not have to be diverted to Los Silos in future,” Hernández affirmed.

Wastewater purification, a historical obligation with Isla Baja
An Issue of Priorities
In light of this pressure and with subsequent support solely from the Buenavista council, the previous Cabildo government opted to prioritise municipal over regional decisions. By the end of 2021, the Island Hydrological Plan included the proposal put forward by the city council, which involved the construction of no fewer than six natural treatment facilities in Buenavista alone. These facilities, being municipally governed, were to be initiated by the corporation itself; however, no formal project was presented, only an evaluative report that, according to sources from the Island Council, lacked technical credibility in terms of its compliance with the Hydrological Plan regulations.
As for the Los Silos City Council, in 2022 it sought a study for implementing a comprehensive treatment facility, as defined by the European Commission, in the El Polvillo area, which is where the waters from Los Silos and Garachico converge. This assessment highlighted the requirement to expropriate a total of nine hectares of existing crops for construction.
It was at this juncture that this alternative was conclusively dismissed, reverting to the solution initially suggested by the insular Water Council, which involves the establishment of the regional treatment facility utilising a membrane bioreactor system. This will render available a total of 1,000 cubic metres of water per day for farmers, in contrast to the 500 cubic metres currently being lost solely in Garachico and Los Silos.
Since that time, as the saying goes, much has changed, but in this instance, not enough rain has fallen to fulfil the water requirements of the region. While valuable time and, notably, the funding we had in 2017 has been squandered in the area, we find ourselves back at the beginning. Now, the Buenavista council, following a shift in government after the recent elections, has indicated the urgency for a solution akin to that of the rest of the Island, prompting the resumption of the aforementioned project’s drafting, which will benefit roughly 8,000 residents of Isla Baja.
It is evident that prompt action is essential, as 30% of the wastewater in Isla Baja is not being treated properly. These statistics are tantamount to discharging four Olympic-sized swimming pools of untreated wastewater into the aquifer each week, raising concerns about adequate treatment. This significantly affects a particularly scarce resource, water, and could have detrimental effects on the sea as well. Environmental legislation and societal pressures compel both institutions and citizens to act responsibly and address this issue, which could incur severe penalties amounting to 8,000 euros per day for non-compliance. This process has already accumulated over a decade’s worth of delays.
The platform continues to advocate for the same demands, promoting a more environmentally friendly alternative while criticising the administrations for their lack of response over the past four years. According to their spokesperson, the treatment facilities established in other areas of the Island are outdated and lack the necessary sewage systems, rendering them ineffective “as demonstrated in the case of Playa Jardín in Puerto de la Cruz.” They emphasised that the fundamental structure has been improperly laid, whereas the solution should involve smaller natural purification plants that require minimal maintenance, are far more ecological, and have a lower pollution footprint.
What actions are farmers taking?
Throughout this period, we have also been faced with a water emergency declaration for the Island, which has exacerbated the situation. To address this crisis, measures have been implemented in collaboration with the private sector, such as the initiation of desalination plants for the irrigation communities of Funche and Savasa Agrícola, with capacities of 2,000 cubic metres/day and 600 cubic metres/day, respectively. Furthermore, the surplus production from the Buenavista Golf and La Monja desalination plants is now available to the Insular Water Council.
Moreover, the General Directorate of Water of the Government of the Canary Islands has another facility planned for Balten, with a capacity for an additional 2,500 cubic metres per day. The Cabildo has allotted a subsidy of 1.4 million euros to the Buenavista council for the municipal wastewater purification and discharge regularisation project, along with 129,000 euros for network losses.
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