Water, Sewage & Effluent Mar Vol 30 No 2 | Page 23

La Trobe describes WSE’s first pilot
project with vetiver grass in 2005 and
in 2006. The company renovated an
Aids community centre near Lanseria.
Conventional onsite treatment could not
be used because of the proximity to the
Crocodile River, and they needed to put in
a closed circuit sanitation system. So they
constructed a wetland using vetiver grass,
and here the grasses proved their superabsorbent qualities.
“Most importantly, the vetiver absorbed
all the nitrates and all the phosphates.
Vetiver is an amazing plant: it also absorbs
certain heavy metals. Where you have
bacteria like E. Coli, the bacteria attach
themselves to the root system, resulting
in E. Coli counts of zero. The results were
impressive.
La Trobe does not advocate that the
vetiver grass system is a one-size-fitsall solution nor does he advocate that it
replace entire treatment systems. He says
that mechanised plants are necessary for
large metros, where space is at a premium,
and where the budgets are higher. He
advocates these systems for small to
medium municipalities and
rural communities.

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Pilot project

“We also advocate that the passive system
could be plugged in at the end of any
process, as a final polishing stage, which
will provide a back-up system to ensure a
compliant quality discharge, in the event of
a mechanical breakdown.”
China and Australia were some of the
earliest countries in the world to conduct
vetiver research and application in soil
erosion and environmental amelioration.
Vetiver grass has been applied to
agriculture across the globe to reduce runoff and erosion and to stabilise slopes. In
the last decade, significant research and
numerous projects have demonstrated the
success of vetiver used to treat various
forms of wastewater, including landfill
leachate, domestic sewage, and
industrial wastewater.
Many municipalities cannot afford to
run their highly mechanised systems,
and 80% of municipalities are in this
predicament. La Trobe explains that they
are not attracting the expertise they need,
being engineers and millwrights, nor raise
the operational budgets. The money needed
to provide adequate mechanical treatment
for most of our municipalities’ backlog,
substantially exceeds the total budget
available to them.
“Engineers need to advocate technology
that fits our parameters better,” he says.
“They need to ask what the municipalities
can afford. In some instances the required
operating budget for the treatment plant
accounts for most of the operating budget
for the whole municipality, but they insist
on additional mechanised plants, because
they perceive that this is the only option.
“The highly mechanised wastewater
solutions are very good, but the social
and economic situation has changed
and it’s time we re-look our approach to
wastewater treatment and implement
sustainable solutions,” says La Trobe. He
puts forward that the municipalities have
a host of pressing needs and not all the
budget can go on wastewater treatment. No
single department has enough money to
do what they have to do, despite frequent
interventions by national government.
“In any environmental 7