Justification for community-scale photovoltaic-powered electrodialysis desalination systems for inland rural villages in India

• Published in: Desalination 2014-11, Vol.352, p.82-91
• Main Authors: Wright, Natasha C., Winter, Amos G.
• Format: Article
• Language: English
• Subjects: Applied sciences; Brackish groundwater; Chemical engineering; Desalination; Drinking water and swimming-pool water. Desalination; Economics; Electric power generation; Electrodialysis; Exact sciences and technology; Groundwater; Groundwaters; India; Membrane separation (reverse osmosis, dialysis...); Natural water pollution; Photovoltaic energy; Pollution; Rural; Small-scale; Villages; Water treatment and pollution
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2014.07.035

This paper 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 live in villages of 2000–5000 people, many of which do not have reliable access to electricity. Most village-scale, on-grid 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 1000mg/L and 30% less at 3000mg/L). At 2000mg/L, 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. •Sixty percent of the land area of India is underlain with brackish groundwater.•System design requirements are determined using technical and ethnographic factors.•Electrodialysis can obtain a high recovery ratio with low specific energy and cost.•In off-grid areas, ED has the potential to be more cost effective than RO.•Direct-drive PV-ED could disrupt the village water purification market.