With limited land availability it would be very difficult to have a low energy treatment solution. In Queensland, Australia, membrane bioreactors have been installed. They can produce a high quality effluent which can be recycled but unit power consumption is relatively high.

Hello Michael! Thank you for your comment. The bioreactors are really interesting. I wonder how much would they cost in terms of "person equivalent" or volumetric capacity and can they be operated in varying capacity? What I mean is if we can adjust their energy demand in any particular time. Actually, the main objective here is to create a Water Management System supplied by locally available Renewable Energy Resources. Such resources are usually intermittent in nature thus we are also looking into integration of energy storage or load shedding schemes for the treatment plant, i.e. the plant can adjust its operation capacity (and energy demand) according to the available energy supply at any particular moment.

I am also considering for low-cost alternatives where, if possible, materials for operational needs can be sourced within the Island itself. This criteria is chosen since one of the problems for such situations is also the difficulty and high cost of importations.

I am also looking into options of having decentralized systems, or small scale system to minimize piping and distribution costs etc...

I would really appreciate your advises on some literature or colleagues that you can recommend...

Solar powered membrane distillation could be other alternative. This technology is not yet commercialized but many researchers are excited to see the potential of this alternative technology.

Thank you Lijo! This technology is very promising indeed... I'll try to dig deeper into this to know its design considerations and its feasibility as applied to my proposed set-up... I would welcome any related papers that you might recommend...

Dear Ryan, of course, you could see many papers in my RG publication list in this regards. Please go through and feel free to contact me if you have any questions...Thank you for your interest...

I think that population density and industrial activities of an island are key parameters for choosing a treatment technology that fits your needs. Usually autonomous and innovative systems, when applied for large wastewater quantities, are very expensive. When implementing such technologies, there is always a risk of low efficiencies ( due to limited applications ). If you need further assistance you should be more specific on the remote island. Here in Greece we have remote islands having over 10.000 residents and lots of small food industries. Also the climate conditions are of great importance when choosing wastewater treatment technologies. So if you can give a specific example of an island, I could be more helpful.

Hello Georgios, Thank you for your insightful reply... My team is currently narrowing down the scope as to how big is the island we are going to consider. You are right, the parameters you mentioned are the same thing we are currently looking into. Currently we are considering islands in the Pacific (Parts of Micronesia and Polynesia). I shall get back to you as soon as we establish such limitations of scope... By the way, do you have any literature that could be our reference in establishing these scopes? Perhaps, a paper about one of the islands in Greece. Thank you in advance for your help.

I will search for something better, but for now I hope this helps you a bit:

http://www.uest.gr/win4life/images/papers/Gikas_Tsoutsos.pdf

You can also check the reference of this study:

http://invenio.lib.auth.gr/record/122509/files/GRI-2010-4842.pdf

To conclude this question, my team decided to use the Membrane Desalination Technology (as suggested by Lijo Francis). A system was designed to provide drinking water for 100 p.e. in a tropical island. Economic analysis shows that the system is an attractive option for drinking water supply in small islands.