PhD chemistry students Anton Hamann, left, and Jonathan Hay with the Closed Cold Water Recycling-System they developed for their laboratory at Stellenbosch University. Picture: Stefan Els
Johannesburg - A relatively  inexpensive system developed by three chemistry students at Stellenbosch University have developed an innovative way to reduce the water used by the university's laboratory by 3 000 litres a week and is set to make a big impact on water savings in the drought-stricken Western Cape.

In response to a challenge put out by their head of department, Prof Peter Mallon, to develop ways of saving water, PhD student Monica Clements, Jonathan Hay and Anton Hamann started to conduct trials four months ago in the medicinal and organic chemistry laboratory in the De Beers Building of the university. 

They first identified the largest consumers of water and then developed a system, called a Closed Cold-Water Recycling System (Ccwrs), to be used with various water thirsty lab equipment. 

The system consists of a cooler box, a garden hose and laboratory silicone piping, as well as a garden fountain pump of 80l/h and the basic principle is that the water is cooled down with ice and then recycled in a closed system, whereas previously perfectly potable tap water would have gone down the drain.

Hamann said the system could be set up for under R1 000 with the pump being the most expensive component, which costs on average about R500 as a relatively cheap cooler box, which could contain about 40 litres of water can be used or even a plastic drum which can hold 40 litres of water or more while about 5 litre of ice is needed, depending on the size of the lab equipment. 

He said with Cape Town currently undergoing Level 5 water restrictions imposed by the City of Cape Town recently, he encouraged other university labs to do the same as it would make a big impact on water savings in the province.

The major water-user identified by the students was the lab's rotary evaporators, which used over 100 litres of water a day when running directly from the tap.  Hay said all three of the lab's rotary evaporators had been running on this setup for over three months, without failures, running eight hours a day, Monday to Friday.

The students found that this method of using ice cold water allowed the solvent to condense far quicker and that it is also far more effective in condensing low boiling solvents.  The group said another significant water user was the vacuum suction filtration process, which consumes significant quantities of water in a very short time and instead of each student making use of their own water suction filtration setup in their fume hoods, the lab now has one setup with a Buchi pump which uses no water at all.

"This method of filtration was recently applied in the undergraduate laboratories, where the amount of water saved thus far has been massive. In addition, this method has the advantage of being significantly more efficient, resulting in a much faster and drier filtration step that allow students to continue to the next step more quickly," said the group.
Prof Willem van Otterlo and Dr Margaret Blackie, the research group leaders for the laboratory said they hope this initiative would motivate other research laboratories to look for innovative ways of saving water.