Is it still the high energy consumption demand that restricts the application of seawater desalination ?

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Many small but populated by people islands in the Mediterranean Basin are dry with limited fresh water resources. In addition, quite often salt water intrudes into their few aquifers deteriorating the situation in terms of potable water availability to their inhabitants. On the other hand, during summer, in some of them, the population significantly increases due to tourism increasing at the same time the demand for fresh water. To handle this increase in fresh water demand, water usually needs transporting to the islands, but their long distance from the mainland leads to a high cost. Could the construction of some small-sized seawater desalination plants be a rational solution to the problem? Is it still the high energy consumption demand that restricts the application of seawater desalination methods like reverse osmosis membrane technology in these remote places where seawater is abundant and seawater desalination could indeed improve the quality of life of the inhabitants?

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8 Answers

  1. Good evening to everybody: Dear all. I have entered as a guest few weeks ago and I would like to congratulate you for this interesting article. I was born in Spain in a small archipelago called Canary Islands and many of the situations described above seem familiar to me. In fact, the cost of desalting a cubic meter of water from the sea is very high. Thanks to the inclusion of ERD it has dropped a little bit but it is still a bit high. If you use Distillation Methods to desalinate water you will require a complex system to remineralize the permeate. So by using membrane methods the water quality is less than using distillation but on the other hand their cost will be also fewer. I go along with Jean Marius in considering of waste waters revalorization for a productive organic farming as a valid solution in terms of water reuse. This method together with a good disinfection method (such as Ozone or UV post- treatment) will help you produce potable water with the best warranties of consumption under no risk. Thanks very much for giving me the opportunity to express my own ideas. Best Regards

  2. French English Leonardo Excusez moi pour le retard à répondre L'eau potable du robinet de l'habitat est la plus sécurisée contre certaine pollution des sols. Si les utilisateurs/consommateurs de l'eau dans l'habitat adhèrent à la charte Biologique de préservation de la caractéristique biologique de l'eau, en devenant eau usée cette eau est traitée épurée pr un procédé biologique et le reliquat d'eau rejeté est biologique; il sert alors à l'irrigation de toute culture. Excuse me for the delay in responding Drinking water habitat valve is the most secure against some soil pollution. If users / consumers of water in the habitat adhere to the charter of Biological preservation of biological water feature, becoming the waste water purified water is treated by a biological process and the remaining water is rejected organic; then it is used for irrigation of any culture.

  3. not only the energy consumption, cost is also a big problem with these plants.

  5. The domestic waste waters, soiled by human organic waste, are a gift of life, to make reappear a life but it is impossible to make drinking water of it. But if the waste waters are recycled for the watering of the vegetable garden, one does not consume drinking water. By this economy one preserves a rare resource: water

  6. Not it is impossible, unthinkable. The waste waters contain a strong pollution which I call diffuse (urea, ammonia, nitrogenize, nitrate mugs up phosphate etc) that no however powerful device cannot eliminate. Nature alone in is able by the vegetalized biodiversity but it is long, very long. On the other hand if one uses water recycled for all that is cleaning of vehicle, watering of pleasure garden, watering of vegetable garden, that constitute I think a certain saving in drinking water consumption. One needs thus more to invest in a desalination plant.

    1 Comment

    1. Now I got your point. Acctually, there is some contries doing direct reuse (sewage to potable), whit membranes and oxidative process, in midle west (this is just a note, ok? - issue for another discution, in some other time :) ). thanks for answer! Best Regards!

  7. Hello George, how you're doing? The São Paulo Northern shore lives, from a long time on, a very similar paradigm. In summer vacations (that goes from november until the end of january), the shore suffer with a great scarcity of fresh water, seeing that is necessary to increase the water sending from the interior to this part of the state. And even with this current option of bring fresh water from other parts by pipes, SABESP (the agency that supply water and wastewater treatment in São Paulo State) in seeking for some alternative solutions, as the desalination process. But what is their concern about the desalination process on the São Paulo Northern shore? electricity as you said? not exactly. SABESP main concern is to ask for a bid covering all the technical, economical and polical aspects of the supply chain (captation, desalination, quality control, distribution and concentrate discharge) of the desalination process, paying for those services by the m³ of treated water (BOT). Obviously that this is the most dificult part of the job (find the resources and the company capable to do that in large scale - 1 to 3 m³ per second). Using the largest seawater desalination plant in Brazil as exemple, located in the archipelago of Fernando de Noronha (543 km from the shore), there are a population of 3.400 people and a visiting of 700 turist per month. the system produces 27 m³/h of fresh water to supply the whole island, at the same time with a weir. curently they are having some trobles because the Island weir became dry. because of that, the water in the islands became scarcer. At the same time, tthe eletricity of this system is provided form a power generator plant by diesel (90%) and eolic energy (10%), and the disttibution is done part by pipes and part by trucks. So, analysing those cases, I think that the energy for the system supply is not a isolate issue on the desalination on islands, but the whole operational thing (collect, treat, distribute, discharge, treat the sewage, make the quality control, etc, etc.) as well the money (who is going to pay for this structure?) must be "on focus" before take this decision of install and use water from desalination plants in Islands. I really think that it may be a viable option, but the issues shown above must be analysed first. Well, that's my opinion, thanks for read it! Best Regards, Léo.

  8. I have a much better solution; The revalorization of waste waters for a productive organic farming. Several advantages: Water at will to sprinkle and even more in strong multitude tourist on the island. To make the ground of the island very productive for the development of the vegetalized biodiversity. To reduce the drinking water consumption. To produce agronomy on the spot. To reduce the cost of treatment of household wastes of the island. Indeed more the share of time the collection is evacuated on the continent. the desalination will produce even more waste waters which will be rejected unsuitable into the sea in which this water comes.

    1 Comment

    1. Hello Mr. Marius. So, in fact, your sugestion is to do reuse for agriculture. But for fresh (potable) water? are you sugesting to do potable reuse of the wastewaters generated in the islands as well? May you give us a more precise explanation, please? Thank you for your attention. Best Regards!