==Construction, operations and maintenance==
[[Image:DistillationSetup.jpg|thumb|right|350px|]]
[[Image:Distillation.jpg|thumb|right|350px|Simple distillation and condensation.]]
Of the desalination methods available, the two main ones are: '''reverse osmosis''' and '''distillation''' followed by condensation.
'''Alternative low-cost distillation method'''
A simple, low-cost method to desalinate sea water by distillation is used in some countries where fuel is available. It requires basic kitchen utensils: two pots, one four times the size of the other, and a plastic sheet. The smaller pot is placed inside the larger one and weighed down with a stone.
Sea water is poured into the outer container up to the brim of the inner one. The larger pot is sealed using a plastic sheet and a piece of string so that the plastic sheet sags in the middle (Figure 6). This home-made still is then placed on any heat source such as a stove or wood fire, at low temperature. In a few minutes the sea water in the outer container starts to evaporate. As the plastic sheet prevents the steam from escaping, the droplets condense into the smaller vessel. Residual salt remains in the outer pot.
To conserve fuel, a still can be placed on top of a cooking- pot which is used everyday, such as a rice pot. As it boils or simmers, the 'waste' heat is usefully harnessed.
Care should be taken to ensure that all pots are stable and out of reach of young children.
====Maintenance====
Water produced by desalination is low in minerals and usually aggressive towards materials with which it comes into contact, such as materials used for distribution pipes, storage and plumbing. During post-treatment, the water must be stabilized or re-mineralized prior to distribution to reduce its corrosive nature. Stabilization is commonly achieved by adding chemical constituents such as calcium and magnesium carbonate along with pH adjustment or through blending with small volumes of mineral-rich waters.
