Dimas Siregar, Jakarta Globe 2 Apr 10;
Karawang, West Java. Researchers debuting a new device to purify heavily polluted water took on one of the country’s biggest challenges to demonstrate their invention: the 322-kilometer-long Citarum River in West Java, which has earned the reputation as one of the world’s most polluted waterways thanks to the more than 500 factories that choke its banks.
In front of a crowd of journalists on Wednesday, scientists from the Physics Research Center at the Indonesian Institute of Sciences (LIPI) took a sample of the dark brown river water and poured it into a portable water purifier. The water emerged clear and drinkable .
Researchers said the machine could process 10 liters of the heavily polluted water into potable water in just one minute.
Unlike other portable purifiers, the new, unnamed device combines three methods of purification to take heavily polluted water from brown to clear.
In the first stage, the water spins through a stainless-steel cylinder, which creates centrifugal force that separates out dirt and silt. Nanik Indayaningsih, the lead researcher on the project, pointed to this process as a crucial step in cleaning heavily polluted water.
After its initial spin, the water flows under pressure through a semipermeable membrane that removes micron-sized particles in a process known as reverse osmosis. A micron is one-millionth of a meter.
Many purification systems, especially those used for bottled water, use reverse osmosis, but with such heavily polluted source water, Nanik said the water must go through an ultraviolet purification system before it can be deemed potable.
Ultraviolet systems zap contaminated water with high-energy ultraviolet rays. The ultraviolet radiation does not destroy remaining bacteria, but renders it ineffective.
“Reverse osmosis is frequently used, and we also use it for our machine, but our superiority is in the stainless-steel cylindrical filter that is contained in the same unit,” Nanik said.
The machine, which measures about three meters by two meters, is powered by a gasoline-powered generator and moved by truck.
Nanik said the machine worked on everything from river water to floodwater, suggesting it will be helpful in flood-struck areas where clean water is scarce.
Recent flooding in Java has brought home the necessity of having effective, portable means to provide disaster victims with potable water quickly.
Research on the efficacy of the stainless-steel cylindrical filter, including testing, took one year and cost Rp 300 million ($33,000). The Health Ministry has already signed off on the potability of the machine’s output, Nanik said.
Scientists who study contaminated water measure its turbidity, a term that refers to how cloudy or clear the water is. Clear water has a low level of turbidity, while muddy or cloudy water has a high level. The more turbid the water, the harder it is to clean.
In Wednesday’s demonstration, the water sample taken from the Citarum River was extremely turbid. After passing through LIPI’s new machine, Nanik said, it registered zero turbidity.
“That means the water is safe to consume,” Nanik said.
So-called clean water can have a small level of turbidity, but potable water must have zero.
Researcher Pardamean Sebayang said the machine could run for about four hours at a time before it must be turned off, cleaned and rested for about an hour.
“But that’s just a rough setting because it will depend on the condition of the source water. The more turbid the water, the harder the machine will have to work and the more often it will need to be cleaned,” he said.
Pardamean said the machine could process 10 liters of filthy Citarum River water a minute, or 20 liters per minute of average water.
Nanik said the institute was waiting for a patent to be issued by the Justice and Human Rights Ministry before introducing the technology to the public.
“It’s not for commercial purposes, as we want to ensure that this technology can help people living in areas where clean water is scarce or those areas hit by natural disasters,” Nanik said.
