No abstract

Groundwater is becoming an increasingly important drinking water source. However, the use of groundwater for potable purposes can lead to chronic human exposure to geogenic contaminants, for example, uranium. Nanofiltration (NF) and reverse osmosis (RO) processes are used for drinking water purification, and it is important to understand how contaminants interact with membranes since accumulation of contaminants to the membrane surface can lead to fouling, performance decline and possible breakthrough of contaminants. During the current study laboratory experiments were conducted using NF (TFC-SR2) and RO (BW30) membranes to establish the behavior of uranium across pH (3-10) and pressure (5-15 bar) ranges. The results showed that important determinants of uranium-membrane sorption interactions were (i) the uranium speciation (uranium species valence and size in relation to membrane surface charge and pore size) and (ii) concentration polarization, depending on the pH values. The results show that it is important to monitor sorption of uranium to membranes, which is controlled by pH and concentration polarization, and, if necessary, adjust those parameters controlling uranium sorption.

Supply of potable water requires energy and unfortunately most of the countries with minimal access to safe drinking water are also poor in terms of access to reliable energy grids. However, many of such regions have access to other sources of water (such as brackish and groundwater) that can be treated for producing drinking water if correct treatment systems are put in place. Moreover, many of the electrically remote areas are rich in terms of renewable energy (RE) resources (such as wind and solar) which can be potentially employed as the main source of energy for powering water purification systems. Therefore, development and implementation of off-grid RE powered contaminant removal systems, for producing freshwater from available resources (such as brackish and groundwater), can be considered as an effective and potentially sustainable solution for overcoming the drinking water scarcity issue in remote regions of developing countries. This chapter revises the state of the art related to desalination systems using electrodialysis technology powered by wind energy for decentralised water production.