Bacteria harnessed to solve
wine-farm pollution problems
Printed in: Farmer's Weekly, 15 June 2001
With an increase in intensive farming, getting rid of smelly
effluents has become a problem, even in the wine industry.
A soil and irrigation expert discusses a new way to get rid
of this waste.
The use of intensive-farming methods is giving way to smelly
effluents that are generally associated with factory farming,
where the disposal of manure and other wastes is an increasing
problem. Nowadays even "clean" agriculture, such
as the wine farms of the Western Cape, is contributing to
the pollution of our environment.
Dr Jean Piaget, one of South Africa’s foremost authorities
on soils and irrigation, says he has seen streams running
red with winery waste water. He says he is concerned about
both the unnecessary waste of water and the fact that the
effluent is so acid that it is bound to harm aquatic life
and users lower down the stream.
Dr Jean Piaget is one of South
Africa's foremost authorities on irrigation and water quality
Despite his concern, he says the problem is not difficult
to deal with. A system that uses microbes to clean the effluent
and air bubbles provided by air "injectors" may
be the solution.
However, these injectors are imported from America. Farmers
have to pay for them in dollars, and sometimes they have to
be matched to heavy-duty macerating pumps that can cope with
the detritus in ponds filled with untreated wash water. Many
farmers draw the line because they say the pumps are too expensive.
"Wine farmers will happily spend many thousands of Rands
on stainless-steel plumbing and imported oak vats," Dr
Piaget says, "but when it comes to cleaning up the mess
they make, they unfortunately become a tight-fisted bunch.
They don’t see the disposal of effluent as important.
"What we need is a complete change of attitude. Waste
products have to be managed as intensively as every other
aspect of intensive farming."
He says farmers should learn how to help nature dispose of
agricultural wastes. If the right methods and equipment are
used, ponds can become smaller and deeper. They can be more
conveniently sited, and free more land for cultivation.
Although effluent disposal might not be a priority for farmers
at present, the scarcity of water will soon convince them
that steps need to be taken to rectify the situation. Farmers
see water as a precious resource and respect it. If it is
used to hose down floors or transport wastes, then there is
an obligation to clean up the water afterwards so that it
is not returned to the environment in a polluted form.
Since the world export markets opened up to
SA wines a few years ago, modern irrigation methods, such
as drip lines and micro-systems, have not only made land more
productive but enabled farmers to cultivate mountain sides
and even small pockets of land in semi-urban areas.
SA farmers have proved they are quick to adopt new methods,
especially when it comes to water conservation. One example
he quotes is the use of plastic sheets that are laid on the
land in broad strips. The vines are then planted in holes
in the plastic. The method keeps the moisture in the soil,
and competing weeds don’t grow in the darkness under
the black plastic. Initially farmers were skeptical. Even
when the technique was demonstrated on alternate rows in the
same field with dramatic results there were reservations.
"They told me that to produce good wine a vine must
struggle," he says. "The plastic made it too easy
for the root stock, and the quality would suffer, but these
fears have proved groundless, and today the use of plastic
sheeting is an accepted practice."
SA farmers were also quick to use drip-line irrigation. "In
fact they were too quick and were using the system before
we understood how to space the drippers to suit the soil conditions,"
he says. "The initial results were sometimes disappointing,
but farmers were not put off, and drip-lines are now making
South Africa also invented micro-irrigation. Dr Piaget helped
to pioneer the system. "A mining engineer came up with
the idea as a way to keep mine dumps damp to solve the dust
problem" he says. "It worked so well and it used
so little water that the agricultural potential was quickly
realised by a local farmer. The rest of the world learned
from South Africa."
Dr Piaget says SA farmers have been quick to embrace ways
to get the best possible value out of the country’s
scarce water resources, but they have not been prepared to
take a holistic view of intensive farming. He says they spend
money on modern irrigation equipment to put good water into
the vineyards, but they are not easily prepared to spend money
on the treatment of their effluent.
Lack of suitable training in effluent disposal may be one
of the reasons why wine farmers are not dealing with their
waste effectively. Dr Piaget says he has pointed out many
times that viticulture students in Stellenbosch receive too
little training in effluent disposal despite the fact that
it is a vital part of wine making.
Training wine makers-to-be in effluent disposal is one thing,
but getting them to put the knowledge into practice is another.
"I hope the necessary courses have been introduced,"
Dr Piaget says, "but even if they have, it will still
take a long time before the knowledge is out there on the
He tells the story of how he received a lecture from an American
traffic cop after he had parked in a "blue for disabled"
parking bay near a hotel. The gist of the cop’s message
was that "in America NO means NO".
"That’s what we have to learn in South Africa,"
he says. "When we lay down the law on how water can be
used and how our streams and rivers must be kept free of pollution
NO must mean NO." — by Tony Robinson