Justification of village scale photovoltaic powered electrodialysis desalination systems for rural India

Abstract

This thesis justifies photovoltaic (PV)-powered electrodialysis (ED) as an energy and cost-effective means of desalinating groundwater in rural India and presents the design requirements for a village-level system. Saline groundwater, which underlies 60% of India, can negatively impact health as well as cause a water source to be discarded because of its taste. A quarter of India's population lives in villages of 2000-5000 people, many of whom do not have reliable access to electricity. Most village-scale, ongrid desalination plants use reverse osmosis (RO), which is economically unviable in off-grid locations. Technical and ethnographic factors are used to develop an argument for PV-ED for rural locations, including: system capacity, biological and chemical contaminant removal; water aesthetics; recovery ratio; energy source; economics of water provision; maintenance; and the energetic and cost considerations of available technologies. Within the salinity range of groundwater in India, ED requires less specific energy than RO (75% less at 1,000 ppm and 30% less at 3,000 ppm). At 2,000 ppm, this energetic scaling translates to a 50% lower PV power system cost for ED versus RO. PV-ED has the potential to greatly expand the reach of desalination units for rural India. Additionally, a theoretical model for an electrodialysis system is presented and validated through experimental trials.