CU News

Chula Engineering Cures Salty Tap Water with NanoTech

During the dry season this year, Bangkok residents have faced the saltiest tap water problem in 20 years as a result of global warming and seawater rise. Chulalongkorn engineers predict the problem to persist until May and have proposed solutions with desalination technology.

“Salty tap water” in the dry season has become a big annual problem for people in Bangkok and its suburbs. This year, the water salinity is the most concentrated in 20 years and may pose a risk of kidney disease and high blood pressure from drinking the water that contains salt or sodium chloride exceeding the World Health Organization standards of 250 mg per day.

“In the future, the problem of salty tap water in our country will become more and more serious,” said Prof. Dr. Pisut Painmanakul, an Environmental Engineering expert.

The first reason for this problem is sea level rise because of climate change, causing saltwater to reach the Chao Phraya River, especially on the eastern side of Bangkok.  The second reason is reduced water pressure from the Ping, Wang Yom and Nan tributaries during the dry season with up to 70% of the water being drawn to supply agriculture, livestock, and industries; and the third reason is the high salination of surface water systems that are the sources of our tap water.

To resolve this problem sustainably, all three problems must be addressed at the same time, especially the low water pressure that needs involvement from many parties.  Equally urgent is the quality control of drinking water for consumers. The Center of Excellence in Environmental Engineering, Chulalongkorn is offering a service to measure water salinity using cutting-edge, world-class equipment, as well as consultation on water treatment systems to various departments and the general public.

Moreover, over the past three years, the Center has collaborated with the National Center for Nanotechnology (NANOTEC) to study intelligent nanotechnology to solve the problem of salinity in tap water with new materials and the use of electric current to separate salt particles from the water called Electrodialysis“.

“In Reverse Osmosis (RO) water filtration, we are researching new materials to be used in addition to RO Membranes, which are capable of desalinating the water and capturing even the smallest fluoride-level particles, called Ultrafiltration Membrane.  Moreover, we also study about Electrodialysis process that pushes the salt particles out of the water using less water pressure, but yielding good water quality,” Dr. Jenyuk Lohwacharin, Director of the Center of Excellence for Environmental Engineering, spoke of the results of this research.

This desalination technology is currently under development and is expected to be available to the public shortly.  In the meantime, Dr. Jenyuk advised consumers to drink RO-filtered water for health reasons.

“RO system gives consumers clean water free of Sodium chloride, but it is also free from all kinds of minerals, and is not suitable to drink regularly, as it can cause minerals deficiency.”

“A good practice is to mix fully RO treated water with filtered water with turbidity, chlorine odor, and hardness removed, so you can have drinking water not affected by salt but still has retained some important minerals,” Dr. Jenyuk recommended.

In addition to taking care of drinking water for the household, both environmental engineers hope to persuade everyone to help reduce water usage from the Chao Phraya River to normalize the water pressure in the river, including avoiding reserving water during the seawater rise (14.00 – 16.00).  More importantly, people should reduce the consumption of salty foods.

The Center of Excellence in Environmental Engineering is located on the 4th floor, Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University.  It is the foremost environmental research body in Thailand and the world, with an extensive international research cooperation network, including the U.S. and Taiwan to name a few.  The center has also built highly sophisticated research platforms, including adding value to environmental waste.  It also provides analytical services for various substances with modern and advanced technology including bio-organisms, sodium chloride, and microplastic which is a pollutant originating from marine waste.

For agencies interested in receiving these services, please visit

Chula’s encouragement and support for research is excellent for teachers, students, and the public.

Associate Professor Dr. Suchana Chavanich Faculty of Science, Chulalongkorn University