Solar Desalination with Capacitive Deionization

EPA Grant Number: SU836777
Title: Solar Desalination with Capacitive Deionization
Investigators: Lin, Shihong
Institution: Vanderbilt University
EPA Project Officer: Sergeant, Anne
Phase: I
Project Period: September 1, 2016 through August 31, 2017
Project Amount: $9,554
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2016) RFA Text |  Recipients Lists
Research Category: Sustainability , P3 Awards , P3 Challenge Area - Water

Description:

Develop a brackish groundwater desalination process that couples an emerging desalination technology, capacitive deionization (CDI), with a solar panel: Design and fabricate the CDI cell, design the control system, assemble and test the unit.

Objective:

This project aims to develop a brackish groundwater desalination process powered by solar energy. The system will be built by coupling an emerging desalination technology called capacitive deionization (CDI) and a solar panel as the power source. Providing safe portable water to small communities with limited access to large infrastructures of power and water supply is a big challenge of great importance, especially in many developing countries. The system we propose to design and build in can utilize solar energy to desalinate brackish groundwater and disinfect the water to become portable, and is thus a sustainable approach for supplying water to communities in remote area where access to grid energy and water infrastructure is limited.

Approach:

CDI is a novel desalination process that utilizes high surface area polarizable electrodes for separating a saline solution to a deionized solution and a concentrated solution. As an electrically driven separation process capable of removing ions and small charged molecules from the feed water, CDI is low pressure, low temperature, and low voltage (typically <1.5V) process that is energy efficient for brackish water desalination and inherently compatible with solar energy. It has certain technological advantages over conventional thermal or membrane based desalination process particularly in small-scale off-grid applications. 

In this project, the student design team will design and build a solar powered CDI system that supplies portable water to small communities using brackish groundwater as the water source. The project involves designing and fabricating the CDI cell (the core part of the system), designing the control system that coordinates different components in the system, assembling the system, and finally testing the system with real brackish groundwater. In order to provide safe drinking water free of pathogen, a solar powered UV disinfection system will also be installed.

Expected Results:

The major expected outcome of the project is a working CDI desalination system that is solely powered by solar energy. Such a system includes a CDI desalination cell, a flow circulation and water storage system, a power generation (solar panel) and storage (battery) system, and an automatic control system that coordinates the functions of the different subsystems. The system will be able to reduce the total dissolved solids (TDS) and other ionic contaminants in the feed water.

Supplemental Keywords:

capacitive deionization, brackish water, desalination, solar power;