Young female lecturer researches new technology to turn salt water into fresh water

The practical research of a female lecturer from the mountainous town on saline water treatment technology has entered the final round of the 2024 Science and Technology Award for Young Lecturers.

With the research topic of the combined membrane system FO-MD to treat saline water to provide clean water for coastal and island areas, Dr. Nguyen Thi Hau, lecturer of the Faculty of Chemistry and Environment, Dalat University, became one of 17 authors to enter the final round of the Science and Technology Award for young lecturers in 2024.

This topic was evaluated by scientists in the jury as having high practical value, along with 16 other topics surpassing hundreds of research works and scientific publications and transfer products of young lecturers from 29universities across the country.

Find the optimal solution

Dr. Nguyen Thi Hau shared: "Global climate change is becoming increasingly serious and is forecast to have complex developments in the coming years, most clearly manifested by unusual weather phenomena such as floods, landslides, droughts, and saltwater intrusion occurring frequently and for a long time, seriously affecting people's lives. In particular, Vietnam is considered one of the countries heavily affected by climate change due to its long coastline."

Young lecturer Nguyen Thi Hau (middle) in the laboratory

According to the female lecturer, in the dry season, the flow of small rivers leads to serious saltwater intrusion in some central provinces and the Mekong Delta provinces. Most wells are contaminated with salt and people have no fresh water to use.

"Currently, there is still no truly effective method to overcome this situation. People there often have to pay very high costs to buy fresh water for use. Therefore, it is necessary to find a clean water source for use in coastal and island areas when the currently applied technologies do not ensure the requirements to create a sustainable clean water source," Dr. Hau acknowledged.

To deal with salinity, turning seawater into fresh water, many technologies have been applied, such as thermal distillation, ion exchange, reverse osmosis (RO), nanofiltration, and electrodialysis (ED). The above technologies all have advantages but have common disadvantages such as high investment costs, equipment that is easily and quickly contaminated...

Therefore, Dr. Hau chose to study the FO – MD (Forward Osmosis – Membrane Distillation) combined membrane technology to find the optimal operating conditions for the FO and MD models and evaluate the efficiency and treatment costs of the proposed technology compared to other desalination technologies currently available in Vietnam.

Low cost, high efficiency

"The FO forward osmosis membrane is one of the world 's new technologies and is highly feasible in the desalination process with outstanding advantages such as: low energy consumption, low membrane fouling, and high desalination efficiency. This is the most effective choice for treating saline water," said the female lecturer.

According to Dr. Hau, the outstanding advantage of this technology is that it operates on the principle of natural osmosis due to the difference in osmotic pressure between two solutions, water will go from the place of low concentration through the membrane and to the place of high concentration. Therefore, the forward osmosis membrane technology does not use hydraulic pressure like reverse osmosis (RO), which helps save energy and reduce membrane fouling, leading to low treatment costs.

Female lecturer worries when people in salt-affected areas have to pay high costs for buying fresh water for daily use

During the research, Dr. Hau decided to choose seawater samples from the coastal areas of Ninh Thuan province and An Binh island, Quang Ngai province for treatment because these areas are facing the most serious shortage of fresh water.

The results showed that the FO-MD system achieved high salt removal efficiency and was independent of the salinity of the feed stream. The dirt on the FO membrane surface was negligible and could be cleaned by rinsing with DI water for 5 minutes and was ready for the next cycle. Furthermore, the FO-MD integrated system could produce high quality clean water because the salt water was treated through 2 membrane stages during operation.

According to preliminary calculations in the laboratory (with solar energy), the total operating cost of the FO-MD system to treat 1 ^m3 of fresh water is 20,389 VND. Meanwhile, the total operating cost for the RO system (reverse osmosis technology) to treat 1 ^m3 of fresh water is 49,160 VND, 2.4 times more expensive than the FO-MD technology.

It is known that this topic was accepted as excellent by Dalat University before participating in the award. "Currently, I am continuing to implement topics of the NAFOSTED fund, Vingroup's project focusing on synthesizing FO and MD filter membranes, using the optimal results in the laboratory to gradually design a seawater purifier with integrated solar energy for application in seawater treatment in island areas and seagoing vessels", Dr. Nguyen Thi Hau shared.

The Science and Technology Award for young lecturers (under 35 years old) in higher education institutions was initiated by the Ministry of Education and Training, in coordination with the Ministry of Science and Technology and the Central Committee of the Ho Chi Minh Communist Youth Union since 2018.

The criteria for the award are that the research work must be novel, creative, have scientific and practical value, be published or applied in practice for at least one year (as of the time of application), and have not participated in or received any national or international awards.

Source: https://thanhnien.vn/nu-giang-vien-tre-nghien-cuu-cong-nghe-moi-bien-nuoc-man-thanh-nuoc-ngot-185241030213818512.htm