Feasibility Study of an Electrodialysis System for In-Home Water Desalination and Purification in Urban India

Desalination of high salinity water is an effective way of improving the aesthetic quality of drinking water and has been demonstrated to be a characteristic valued by consumers. Across India, 60% of the groundwater, the primary water source for millions, is brackish or contains a high salt content with total dissolved solids (TDS) ranging from 500 parts per million (ppm) to 3,000ppm. The government does not provide sufficient desalination treatment before the water reaches the tap of a consumer. Therefore consumers have turned to in-home desalination. However, current products are either expensive or have low recovery, product water output per untreated feed water, (∼30%) wasting water resources. Electrodialysis (ED) is a promising technology that desalinates water while maintaining higher recovery (up to 95%) compared to existing consumer reverse osmosis (RO) products. This paper first explores the in-home desalination market to determine critical design requirements for an in-home ED system. A model was then used to evaluate and optimize the performance of an ED stack at this scale and designated salinity range. Additionally, testing was conducted in order to validate the model and demonstrate feasibility. Finally, cost estimates of the proposed in-home ED system and product design concept are presented. The results of this work identified a system design that provides consumers with up to 80% recovery of feed water with cost and size competitive to currently available in-home RO products

Development of sensor based evaluation methodologies for developing world products

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Cataloged from PDF version of thesis.Includes bibliographical references (pages 88-90).Often consumers in the developed world have a wide range of options available to them when considering a certain product family, such as a smartphone. The plethora of options is in large part a result of the degree to which the supply chains have advanced in the developed world. Organizations such as Consumer Reports have distilled information about the products available to consumer in the form of comparative ratings charts to help them make a purchasing decision. These product evaluations provide valuable information on the quality of a product, but are limited to the perspective of the developed world consumer. In contrast, there are many barriers in providing a product to a consumer in the developing world. A multitude of poverty alleviating products have been developed, but few have been successful. The Comprehensive Initiative on Technology Evaluation at the Massachusetts Institute of Technology seeks to adapt product evaluation methodologies such as those employed by Consumer Reports to evaluate developing world products. This thesis documents the challenges in adapting the methodology and demonstrates that in order to create a successful product in the developing world, aspects of design, manufacturing, distribution, and consumer adoption must be assessed. A biomass fueled improved cookstove case study is presented to explain these four stages and how they may be evaluated. In addition, a sensor based method and neural network based processing algorithm is presented as a cost-effective and accurate way to gauge adoption of improved cookstoves.by Prithiviraj Sundararaman.S.M

Feasibility study of an electrodialysis system for in-home water desalination in urban India

Poor quality of drinking water delivered to homes by state utilities, and a large reliance on brackish ground water resources in parts of urban India, has resulted in the adoption of in-home water treatment solutions. The only existing in-home water treatment solution capable of desalination is reverse osmosis (RO). However, existing RO products can recover only 25â50% of the feed water supplied as usable product water. In this study, an alternative solution that relies on electrodialysis (ED) was designed and experimentally shown to achieve a recovery of 80%, producing 12 L/h of water at the desired salinity of 350 ppm from a feed salinity of 3000 ppm. The cost and size of the proposed system were also found to be comparable to existing in-home RO systems. In-home ED water treatment systems could compete with existing RO products while providing the advantage of improved water-conservation in water-stressed India. Keywords: Electrodialysis, Desalination, Reverse osmosis, Brackish wate