The entire research career of Dr. Li-Shiang Liang (63) has had to do with water. Many of his inventions have refined the process of continuous electrodeionization for the production of extremely pure water for industrial use. One thing that Liang, a great nature lover, is particularly pleased with is the fact that this process has recently proven its worth in a unique plant for seawater deionization which is among the most energy-efficient in the world.

“Even as a child I was very attached to nature, and I have become even more so in the course of my life,” says Liang. At the same time, he has enjoyed building things himself since he was small. “We lived in Taiwan until I was nine years old. At that time there weren’t many toys on sale, so I made my own,” explains Liang. Nature and making things — these two interests have made an impression on his entire professional life. Liang arrived in the U.S. as a teenager, after stays in Trinidad and South America. After graduating from high school, he studied mechanical engineering at Massachusetts Institute of Technology (MIT) and also acquired considerable knowledge of chemistry and biology. He was already involved with the topic of water in his first job as an industrial consultant, as he was responsible for helping large companies to reduce their water consumption and recycle wastewater. “Nowadays that sounds obvious, but in the 1970s it was a very new approach,” says Liang. His next professional position was in a start-up that was involved in water filtration on the micro-scale. The process of rapidly developing new technologies to the point of readiness for production as part of a small team was an important experience for Liang.

Liang then decided he wanted to work in a large company, and became head of development for water treatment technology at the U.S. company Millipore in Lowell, Massachusetts. Millipore’s Water division was taken over by Siemens Water Technologies in 2004. Liang is now Principal Scientist at the company, holding a responsible position in research and development. Many of his inventions over the past 20 years have improved the process of continuous electrodeionization — CEDI for short — with which water is purified of foreign matter and salts. The resulting ultrapure water is primarily needed by steam power plants, in the pharmaceutical and cosmetics industry, and in the manufacture of computer chips and integrated circuits. Liang is captivated by the further development of CEDI because it offers him an interdisciplinary field of work. Chemistry, electrochemistry, and hydromechanics are every bit as important here as his mechanical engineering abilities.

A further application of CEDI seemed for many years to be uninteresting — until, that is, environmental and climate protection became a focus of public attention and new ideas for energy-saving methods of producing drinking water became urgently necessary. Conventional methods for seawater desalination use extremely large quantities of energy. When the government of Singapore announced a competition for energy-efficient seawater desalination, Siemens won with a completely new approach. The company combines the two technologies of CEDI and electrodialysis (ED) in a single plant, which drastically reduces the energy consumption compared to conventional seawater desalination plants. The pilot plant in Singapore went into operation in 2010, it has already almost reached the Singapore government’s specified maximum consumption of 1.5 kilowatt hours per cubic meter (kWh/m³). That is less than half of the 4 kWh/m³ consumed by reverse osmosis, the most economical process to date, and 85 percent less than the conventional seawater distillation processes (10 kWh/m³). The clever part is that Liang and his colleagues succeeded in eliminating old weak points in the design of ED facilities and in developing new membranes for high salt burdens. The seawater flows through three electrodialysis modules, and in the process its salt content is reduced to less than one percent. Further desalinating the water using the ED process would require a disproportionate energy input, so instead it flows through a CEDI module with membranes that are capable of filtering out so much salt that the seawater becomes drinking water.

Plans call for further demonstration units to be set up in the U.S. and the Caribbean by mid-2012. These units are meant to show that the new and economical desalination technique will work not only in Singapore but also at any other location, despite sharp regional differences in seawater salt content. For Liang, this is about more than just his personal success as an inventor: “We need new processes with high energy efficiency and a good CO₂ balance for seawater desalination,” he says. This is particularly necessary in regions with a shortage of fresh water, where current efforts to recycle water and reduce consumption are not sufficient to meet demand.

Liang likes to relax in his free time by gardening and taking walks in the woods. Cooking is another one of his hobbies. Liang has registered 62 inventions, which have led to the granting of 84 individual patents and 35 patent families.