I spent yesterday afternoon with an extremely interesting man and his partner. He was an agricultural engineer, speaks many languages and plays several instruments. A man of many talents. He gave me a copy of the following letter he sent to a publication. Thought it might be of interest to those of us worried about the extreme drought and lack of water in the region, as it is about desalination. It is certainly food for thought.

In reference to several unfortunately misinformed but surely well-meaning readers letters on the subject of desalination-plant in an eventual Algarvean context, the following:  it is out of the question, and if you will bear with me I will tell you why.
For every 100 cu.m. of very approximately "clean" water one ends up with 3 metric tonnes of very dirty unrefined salt.  All present toxins (=poisons) are hyper-concentrated.
Size of plant:  either use up all the remaining bits of pristine coastline (only lowland - prohibitively expensive to do it where there are Cliffs!), introduce local bathing-bans (giant pump-inlets) or just destroy the lowland coast around Almancil, Quinta do Lago, Vale do Lobo, Faro delta etc...  The size of the plant would necessarily be huge.  Refer please to Saudi Arabia, where I was privileged to work on a similar project.  Your medium-sized oil-refinery complex is nothing in comparison!
Energy-use: Unless one is prepared to utilise the old-fashioned "saltings" method or the newer (Spanish) greenhouse method, which both employ enormous areas of land and in the latter case pesticides (monoculture - agrotoxins), one is confronted with building large (catalysed) industrial complexes, with recourse at the very least to nuclear energy, the disadvantages of which are well known to all of us.
Environmental & economic consequences:  it would be necessary to take all those millions (& it will be millions before long!) of tonnes of very dirty polluted salt (high concentrations of pesticides etc.) & dump it in bulk at sea.  In Saudi, this killed ALL the fish in a radius of approx. 150 km. around the plant - which was an ugly-looking thing anyway, en passant, thus completely destroying the local fishing-industry & the coral-reefs, not to mention Tourism (I told you not to mention that!).
Alternative solutions:  are there any? one wonders, but we live in hope...  Nobody will like this, but:  immediate bans on the use of water for golf-courses; severe restrictions on the watering of (villa/hotel, etc.) gardens & especially Lawns, & a hard brake on further touristic, residential & intensive agricultural development.
Dam-construction is also NOT the answer.  Forget it - it also leads to galloping desertification.
The answer which nobody wants to know is CONSERVATION.

Eric Finshaw, Agronomist specialised in irrigation in development work for 30 yrs.  RSVP (Ed.)

well very interesting....so the simple answer is we all have to cut back.....will we...but of course not...another 100000 villas planned...more dammed golf course..formula 1 race tracks.....more hotels ...well I hope someone in the portuguese government knows the answers ...because I certainly dont.!!

I think the government treat the water problem the same as the one of forest fires-- It might never happen again

Thanks for sharing this guy's views with the forum. I must admit I was one of those people who had always said, why not use desalination plants (especially here in the UK, an island surrounded by water) not giving a thought to what by-products there would be and the affect it could have on the environment.

: Well, very good alternative solutions, Mr Finshaw.
But don't you believe than these propositions are well known by a lot of real estates agents, private investors or local urbanists ?
Look at the anarchic developpement on the coast, vacation houses lost in the vegetation on Monchique mountain...
Sorry for my approximate english

Yer, me too Witchy. They do say a little knowledge is a dangerous thing and a lot of us were talking about desalination plants as an answer to the water problems in Iberia weren't we? After I read the letter and spent some further time talking to him about this and various related matters it gave me loads to think about. It is good to know as many facts as possible though in order to decide the best course of action for the future. I just hope, like others, that the governments take the problem seriously and don't just sit back and wait and wait and wait.....

which is exactly what they will do...until its tooooooo late.....anyway I always wanted to have a villa in a european iraq...

Why don't you stop the constant whinging and go and do something useful. You just go on and on whining away, it doesn't do anyone any good you know.

Not sure about some of the figures in the original letter. There can be no more salt by product than was contained in the original sea water. 100cm of sea water (which is only a swimming pool full) can't produce 3 metric tonnes of salt.
Most of the salt is returned to the sea at about 1.8 times the original concentration, less than twice as salty as originally.
It depends on the process, distillation or reverse osmosis but the average plant produces about a couple of truck loads of by product per week.
I think there are about 8000 plants worldwide and I seem to remember the Saudi plant is the worlds biggest.

Very interesting.I'm just about to install a reverse osmosis plant in my house .....my water from bore hole is very salty and many other bad things 5700 conductivity etc etc......anybody have any knowledge of these things.....they a fortune but I have no choice it seems.what worries me is the 'Dirty Water' ..40% of theclean..is just dumped on the land again..is this good..is this legal...do these reverse Osmosis machines really work ( This Dutch one injects a sort of Acid into the vfilter.)..
Any advise ..experience ..much appreciated---

Lot of salt isn't it!
One litre of seawater contains around 35g of salt, which is 35kg/cu m, which is 3.5 tonnes per 100 cu m. A tonne always sounds a lot to me, but those big bags of sand from builders merchants weigh around a tonne. It is a problem to get rid of, you can't just chuck it in the sea.

Reverse Osmosis works fine, you have to back flush regularly which throws away some of your water.

This is terribly interesting. http://www.bruzelius.info/Nautica/Provi ... water.html It had never occurred to me where sailing ships got fresh water from. And particularly 'Dr. Priestley has suggested a proposal to give to this distilled water the briskness and spirit of fresh spring water, and, at the same time, of rendering it, perhaps, a remedy or preventive against the scurvy, by impregnating it with the gas or fluid called fixed air, obtained by mixing chalk with oil of vitriol'. Fizzy lemonade anyone?

I was interested in the opinion on desalination in the original posting and have been doing some quiet research myself, in consultation with a hydrogeologist colleague, of the situation here in Oman. There are some parallels with Portugal.

Oman's topography is similar to the Algarve with the majority of the population of 2 million living in a relatively narrow coastal plain between the mountains and the sea. Water supply is partly dependent on natural fresh water aquifers (with the resulting similar problems of over-demand) but mainly, and increasingly, on desalination of sea water. The latter is the only real large scale fresh water option due to the low rainfall - this year we had a few days of rain in January/February, the first significant amount for six years!

The Omanis are mindful of the problems experienced by the big Saudi units but much of the cause of this is the use of short reject water pipelines into bodies of water like the Persian Gulf which is narrow, relatively shallow and already highly-saline due to the high rate of natural evaporation. The Omani plants (like any that might be installed in Southern Portugal) route reject water into the ocean (in our case the Indian Ocean) which is a massive body of water capable of diluting super-saline reject water. Nevertheless, it is still possible to cause problems if the outfall is not sufficiently long. If the reject is discharged into too shallow water a saline algal bloom can result and may wash back towards the coast with the resulting severe impact on natural eco-systems. The solution is to ensure that reject water discharge pipes extend 10 to 15km into the deep ocean and also to regularly survey the local sea-bed to detect and remove any silt build-up.

However, desalination plants are extremely energy intensive - less of a problem in Oman where there is reasonable oil and gas production, but a severe handicap in non-oil/gas producing countries. Partial mitigation can be achieved by combining desalination and power plants and making maximum use of low-level heat (i.e. what would normally go up the power plant chimney).

Another approach that has had partial success here is the use of re-charge dams. These are not built to contain reservoirs but are low level constructions built at the mouths of coastal flood plains that are designed to hold-up rain water long enough to allow the water to sink into the soil, thereby replenishing sub-surface aquifers and lowering the salt table. The main problem here is that the very sparse vegetation in the hills and on the plains allows silt to build up and slow the rate of absorption so evaporation takes over. With the (relatively) higher rainfall and much greater vegetation of Portugal extensive use of the re-charge dam option (if not already practiced) might be a useful supplementary solution to water supply.

re reverse osmosis. We have a small one fitted to supply potable water to our american fridge which we only use for drinking. The majority of our water which is supplied by borehole is initially filtered then passed thru a kinetico water softener then thru a ozone unit before being piped to the house for general use. Obviously the need for the above depends your water analysist - hope this helps

Very interesting Rampage. Perhaps we should pass my friend's and your findings/research to the government and "Aguas do Algarve". They probably haven't found out as much as you both have. Meanwhile, still doing the rain dances in the garden. There were a few spots last Tuesday but that was it.