Solar Powered Decontamination of Groundwater for Reduction of Soil Salinity

Global energy demand is perpetually rising and industrial expansion is the main factor behind it. Most of energy generation methods require substantial intake of water. These technologies also gives rise to problems of pollution and water scarcity. Hence, nowadays alternate energy-based methods are being adopted for water purification. Agriculture is also adversely affected from water scarcity. In addition, salt accumulation in soil due to improper drainage is also reduces the agricultural productivity of the region. This necessitates the utilization of all possible methods for water retention and look for new sources. Around 66% of the agricultural supply water is lost as run-off or agricultural drainage water (ADW). This abundance of ADW has paved way for new methods for recovery of water. Solar distillation units, commonly known as solar stills, are most economical and most promising method for purification of ADW. This process use suns heat as its energy source to offer a feasible solution for ADW purification. The water obtained from this economical process is suitable to reuse in irrigation and even fit for human consumption. The energy required to evaporate water from this process is approximately 2.3 MJ/kg. Though it is more strenuous than reverse osmosis process, the advantage is that it uses heat energy instead of electricity; and it is a negligible maintenance device. Integrating phase change materials to a solar still, that absorbs suns heat energy during the day, and release it to water at night, helps in extending the operation of during nocturnal hours also. A substantial amount of the heat is accumulated by the PCM in comparison to the heat rejection to surroundings in case of simple still. This increases the overall productivity of the still and more ADW can be reused.