Stellenbosch students’ smart water conservation
THREE Stellenbosch University chemistry students have reduced their laboratory’s water consumption by at least 3 000 litres a week by coming up with innovative and relatively inexpensive ways of saving water.
PhD students Monica Clements, Jonathan Hay and Anton Hamann cool water down with ice and then recycle it in a closed system.
Previously, perfectly potable tap water would have gone down the drain.
Four months ago they were tasked by their head of department, Professor Peter Mallon, to find ways of saving water. They then began to conduct trials in the medicinal and organic chemistry laboratory.
They first had to identify the largest consumers of water and then develop a system – called a Closed Cold Water Recycling System – that would then be used with various water-thirsty lab equipment.
The closed system consisted of a cooler box, a garden hose, laboratory silicone piping, and a garden fountain pump of 80 litres per hour.
The students identified the major water user as the lab’s rotary evaporators, which used more than 100 litres of water a day when running directly from the tap.
The evaporator condenser is now connected to the closed system and not to a tap, and uses only about 5 litres of ice water per day.
“All three of our rotary evaporators have been running on this set-up for over three months, without failures of any kind, even though running eight hours a day, Monday to Friday,” said Hay.
This method of using ice-cold water allowed the solvent to condense far more quickly, and that it is also far more effective in condensing low-boiling solvents.
Another significant water user was identified as the vacuum suction filtration process, which consumes many litres of water in a very short space of time.
Instead of each student making use of their own water suction filtration set-up in their fume hoods, the lab now has one set-up with a pump which uses no water at all.
Hamann said: “This method of filtration was recently applied in the undergraduate laboratories, where the amount of water saved thus far has been massive.”
Professor Willem van Otterlo and Dr Margaret Blackie, the research group leaders for the laboratory, said they hope this initiative will motivate other research laboratories to look for innovative ways of saving water.
“In addition, this method has the advantage of being significantly more efficient – resulting in much faster and drier filtration steps that allow students to continue to the next step more quickly,” Hay said.
The group explained that not all initiatives were technical. By simply placing smaller plastic buckets in the large wash basins, they significantly reduced the amount of water used to wash glassware.
Now, one bucket filled with hot water is usually sufficient for washing two students’ glassware a day.