Students design system to save university thousands of litres of water
Science is thirsty work‚ but with a cooler box‚ a garden hose‚ some pipes‚ and a water pump‚ chemistry students at Stellenbosch University in the drought stricken Western Cape are saving 3‚000 litres of water a week.
Chemistry equipment at the university’s laboratories needs a constant flow of cold water to prevent overheating and normally tap water is run through the system and then straight down the drain.
But chemistry PhD students Monica Clements‚ Jonathan Hay and Anton Hamann responded to their head of department Professor Peter Mallon’s challenge to save water by coming up with a “Closed Cold-Water Recycling System (CCWRS)”.
The innovative yet inexpensive system is essentially a cooler box filled with ice water being pumped through a closed system and is currently being used on various equipment at the university’s organic chemistry laboratory.
“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‚” said university spokesperson Martin Viljoen.
The laboratory's evaporators had been identified as the university's major water guzzlers as they used over 100 litres of water per day when running directly from the tap‚ said Viljoen.
The new system has been running smoothly and Hay said their only water usage now comes from washing equipment‚ cleaning‚ and the ice which they have to add to cool down the water.
Using the system has also improved efficiency in the lab equipment. Solvents‚ for example‚ condense quicker because of the use of ice cold water.
Adding a closed system by means of a “Buchi pump” to their vacuum suction filtration process not only cut water usage but also resulted in a “much faster and drier filtration step that allow students to continue to the next step more quickly”.
Students now use as little as 50 litres of water per person per day mostly for washing and cleaning but this can be further reduced by placing a smaller bucket in large wash basins which Viljoen said is usually enough for two students' glassware.