The majority of sewage discharges are not properly authorised or controlled

After a week of debate as whether or not “microalgae” in the waters around Tenerife has been promoted through sewage discharges, it is worth understanding that a 2008 report by the Canary Islands Government Ministry of Environment, after inspections carried out by Civic Engineers Civica Ingenieros S.L., made very clear that 74% of water discharges to the sea in the Canary Islands do not have proper authorisation. A new study, will supposedly be published at the end of this year with the current results. Those released in 2008 were already dramatic, and so many observers fear that almost 10 years later things will be much worse, as the population has grown by more than half a million people and practically nothing has been done to alleviate this great problem.

There are between 500 & 700 discharge pipes to the sea carrying ​​sewage and fecal waters throughout the Canaries and approximately only 20% are authorised to operate. According to data from 2008, 51% of the discharges are made through municipal drains, 30.9% flow direct to the sea  and 10% from submarine outflows.

There are a total of 170 such discharge points on Tenerife alone, of which 120 are unauthorised. The figures indicate that 96 per cent of sewage discharges in Tenerife, 57 million liters, go untouched straight into the sea in violation of European law.

Images from the Canaries Government own files show discharges from land to the sea (Year 2008) on all the islands with green dots, using the information collected in the 2008 “Control de vertidos tierra-mar” census.  A new one is currently being completed. The vast majority of discharges are NOT authorised and it appears nothing is being done to control it.

The data here is all on the Canary Islands IDECanarias Territorial Information System. There is a lot of data. All of it from 2007-2008. We will have to wait for their latest updates to be published, however for comparison the difference shown between the 2001-2003 census and the 2006-2008 census revealed that urban discharges had at that time increased by 45%, imagine what the numbers may be in 2017.


The Government of the Canary Islands has all the information, data and photographs of most of the discharge sites, and despite most not having the proper authorisations, they continue to pump untreated sewage in to the sea without much control.

Source: Canarias en Red

 As we pointed out in a previous article, thanks to the posts of an environmental chemist regarding cyanobacterial “microalgae” blooms surrounding the coastline of Tenerife, the vast majority of harmful pathogens and bacteria in fecal waters are killed as soon as they make contact with the sea, so that is not really the issue.  This same untreated sewage, however, does potentially provide a source of nitrates, phosphorous and organic carbon, which may promote cyanobacterial colonies to form, as they rise from the deep to take advantage of the extra availability of these elements.

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