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A Technical Guide for Wine Producers
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RECENT ARTICLES | WYNBOER HOME
Make red wine the 'green' way
Karin Theron
The cost effective processing of waste water is a major concern for many cellars, but the good news is that the Water Research Commission has joined hands with Stellenbosch University (SU) and the private sector to develop technology that will enable the wine industry in particular to treat their waste water effectively at an affordable cost.
According to Prof Trevor Britz of the Food Science Department at SU, the technology they developed is not new, but its application on a small scale makes it accessible to cellars who have to treat less than 50 000 litres of waste water per day.
A working unit using this technology was recently demonstrated at Rupert & Rothschild Winery in Franschhoek. This unit uses UASB (Upflow Anaerobic Sludge Blanket) processing combined with ozoning to treat effluent.
According to a recent article in Die Burger conservationists are increasingly concerned about the state of rivers in the Western Cape. The article quotes a report by CapeNature indicating that only 7% of the Western Cape rivers are unspoilt and only 25% are in a good condition. Agricultural activities are singled out as a threat to the condition of rivers.
"Cellars should firstly attempt to reduce their waste water. This can be done by applying good cellar practices, for example not wasting any water and keeping solids from entering the waste water, thereby making treatment considerably easier and cheaper," says Prof Britz.
"The ideal would be for cellars to recycle as much water as possible so that the water usage actually forms a closed circuit. There are several advantages for cellars to treat their water effectively on site, for example the water consumption may decrease significantly, municipal levies on the dumping of water may be reduced and useful additives generated by the treatment. Obviously the positive effect on the environment is also an increasingly important factor."
Intensive research regarding this system was initiated at Stellenbosch University in 2003 by Dr Gunnar Sigge and Prof Britz. The research was funded by the Water Research Commission and Dr Neels Barnardt of the private business Enviro Services later collaborated with them to make the research applicable to real life situations.
Laboratory tests resulted in a launch plant at Die Bergkelder which was tested for 200 days, whereafter a commercial plant was constructed. The plant at Rupert & Rothschild has been successfully operational for two years.
The unit, known as the Active Bioreactor, consists of eight tanks coupled in parallel, four recycling pumps, a feeder pump and temperature control, but according to Dr Sigge a UASB reactor unit may simply consist of a closed tank for the anaerobic treatment, feeder and recycling pumps and a feeder tank within which pre-ozonation may take place.
During the UASB treatment polluted water is pumped through a bed of grains (known as black gold). During this process organic matter in the water is digested to biogas (a mixture of mainly methane (CH4) and CO2). From this gas mixture further energy may be extracted, resulting in energy savings.
For more information contact Dr Sigge or Dr Barnardt respectively on (021) 808-3581 or 082 457 3316.
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