New method to purify water used in oil refinement

Scientists, including one of Indian origin, have developed a process to remove nearly all traces of oil in produced water -- a byproduct from the oil refinery and extraction process.

About 2.5 billion gallons of produced water is generated each day in the US. Handling that water is a major challenge in the oil refinery industry, particularly because it is deemed unusable for household and commercial use because of remaining contaminants.

Several commercial treatments are available, but they are expensive, do not remove all traces of contaminants from water and can be energy-intensive.

Researchers at the Purdue University in the US have developed a process to remove nearly all traces of oil in produced water.

The process uses activated charcoal foam and subjects it to solar light to produce heat and purify the water. The foam absorbs the oil contaminants from the water.

"This is a simple, clean and inexpensive treatment process," said Ashreet Mishra, a graduate research assistant at the Purdue University.

"I have seen in my home country of India how people suffer for the want of pure water, and we as researchers need to do as much as we can to help," said Mishra.

The process meets all enviromental standards for clean water from industrial sources and had a total organic carbon of 7.5 milligrams per litre, said Mishra.

Another advantage is that the oil absorbed by the foam can be recovered efficiently, he said. The researchers were able to recover up to 95 per cent of the oil that was absorbed.

"This is the first-of-its kind method to do this purification in a single step simultaneously via a perforated foam. Our process is able to address the cost and energy aspects of the problem," Mishra said.

The process could be integrated with existing disposal systems to purify a large amount of water and reduce the current stress on water grids.