Desalination is a popular source of potable water in Middle Eastern countries, where large energy reserves and the relative scarcity of water suitable for drinking led to desalination in the region accounting for close to 75% of total world capacity in 2007. If that figure hasn’t already dropped it almost certainly will as access to clean water becomes an issue for many places around the globe. And the shortage isn’t just limited to developing countries, with places like California and parts of Australia facing their worst droughts in recorded history. A new mini-mobile-modular (M3) “smart” water desalination and filtration system could help determine the feasibility of desalination in areas that may be considering it for the first time.
Designing and constructing new desalination plants involves the expensive and time-consuming step of creating and testing pilot facilities. Traditionally, small yet very expensive stationary pilot plants are constructed to determine the feasibility of using available water as a source for a large-scale desalination plant. The M3 system developed by researchers at the University of California, Los Angeles (UCLA) Henry Samueli School of Engineering and Applied Science helps cut both the cost and time of desalination plant design and construction by providing an all-in-one mobile testing plant that can be used to test almost any water source.
"The advantages of this type of system are that it can cut costs, and because it is mobile, only one M3 system needs to be built to test multiple sources. Also, it will give an extensive amount of information that can be used to design the larger-scale desalination plant," said Alex Bartman, a graduate student on the M3 team.
The system measures water pH, temperature, turbidity and salinity in real-time so it can control a variety or process variables, including the precise measure of chemical additives to condition the water, autonomously. All the valves are computer-controlled, so the system can adjust itself automatically. Also, the system’s software keeps track of how much energy is used and employs various techniques to optimize the system so that it can run with minimum energy consumption.
Although the system is compact enough to be transported in the back of a van, it can generate 6,000 gallons of drinking water per day from the sea or 8,000 to 9,000 gallons per day from brackish groundwater. This makes the M3 an ideal candidate to be deployed to disaster-ravaged locations to produce fresh water in emergency situations.
The M3 system can also be monitored and operated remotely with the research team envisaging a future where many of these systems are deployed all around the world and their operation monitored from a central location.
The M3 demonstrated its effectiveness in a recent field study in the San Joaquin Valley where agricultural drainage water was nearly saturated with calcium sulfate salts. With just one reverse osmosis (RO) stage the M3 was able to recover 65 percent of the water as drinking water. This was the first field study of the M3 and the team claims they could potentially recover up to 95 percent using an accelerated chemical demineralization process that was also developed at UCLA.
Currently in Southern California the energy cost of water desalination of seawater remains the most expensive source of potable water, with treatment forming the bulk and conveyance of the water the remainder of the overall energy cost. This is reversed for the next most expensive source in terms of energy use, water from Northern California. Although desalination is often seen as energy intensive, desalination of water from brackish groundwater and reclaimed water ends up requiring less than half as much energy than either of these sources.
The UCLA research team hopes to reduce the energy cost of desalination even further and believes systems such as the M3 can help achieve this by helping to accelerate water technology development as well as its adoption.
Check out the vid below to see UCLA’s Prof. Yoram Cohen discussing the M3 system.