sábado, 3 de maio de 2008

Ecotecnologia do Sistema Vetiver na melhoria da qualidade da água e do ambiente.

Ecotecnologia do Sistema Vetiver na melhoria da qualidade da água e do ambiente.

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Vetiver system ecotechnology for water quality improvement andenvironmental enhancement
Vetiver, Vetiveria zizanioides L. Nash, anative grass of India has traditionally
been in use in India for contour protectionand essential-oil production. Taking
clues from its traditional usage in environmental protection, The World Bank
initiated several projects in India in 1980s for systematic development of
Vetiver Grass Technology (VGT), now popularly known as Vetiver System (VS).
Large-scale developments have since taken place in the advancement of VS in
environmental protection1; new avenues have opened up over the past 15 years2.
The VS is emerging as a panacea to a host of environmental problems. It is a
low cost, extremely effective system that offers proven solutions for soil and water
conservation, wastewater treatment, embankment stabilization, flood control,
disaster and pollution mitigation, agroforestry management, and many other
environment-friendly applications being used in over 100 countries3. The VS for
wastewater treatment is a new and innovative phyto-remedial eco-technology,
which has the potential to meet all the right criteria necessary for environmental
enhancement. It is a natural, green, simple, practicable and cost-effective solution,
and its by-products offer a range of uses in handicrafts, animal feed, fuel and
construction applications. Morphological and physiological attributes of vetiver
grass, its strong, deep penetrating (Figure 1 a), aerenchymatous (Figure 1 b) root
system, unusual ability to absorb and tolerate extreme levels of nutrients, agrochemicals
and heavy metals make it anideal system for environmental enhancement
through appropriate interventions in the treatment regime.
The 3rd International Conference on Vetiver and Exhibition (ICV-3), was organized
in Guangzhou, China during 6–9 October 2003 by the Guangdong Academy
of Agricultural Sciences, in association with South China Institute of Botany
(Chinese Academy of Sciences), South China Agricultural University and Guangdong
Association of Grass Industry and Environment. The theme of the conference
‘Vetiver and water’ was truly embodied in the conference deliberations,
highlighting that vetiver (i) is native to hygro-environment such as wetland,
lagoon and bog, (ii) is extremely tolerant to drought as well as waterlogged/
submergence conditions, (iii) is effective for soil and water conservation, and (iv)
is endowed with excellent biological features to ameliorate wastewater and
pollution mitigation. The conference was inaugurated by the Patron of The Vetiver
Network, HRH Princess Maha Chakri Sirindhorn of Thailand, and was attended
by over 230 delegates representing 28 countries. There were 13 plenary presentations
covering eight sub-themes, and 46 oral presentations, including four King of
Thailand Vetiver Award presentations4.Also, an exhibition on VS-based ecotechnologies
and products in the form of posters and demonstration stalls was
arranged at the conference site by various scientific agencies and entrepreneurs.
Further, the organizers had also arranged a one-day study tour for an onsite
live demonstration of VS projects ranging from applications of vetiver in
garbage landfill site management, land slope stabilization and slope aforestation,
and water and vegetation rehabilitation at an ecological park.
Sumit Tantivejkul, Secretary General,Chaipattana Foundation, Bangkok in his
keynote address on Thailand’s experience with respect to vetiver and water, underpinned
the significance of vetiver grass for its deep penetrating root system that
forms an underground wall barrier and helps to filter silt and maintain topsoil.
He stressed that exhaustive experimentation on vetiver system covering over 30
initiatives by the Royal Development Study Centres has since been implemented
all over Thailand by the Governmental agencies for realization of benefits
of vetiver system in soil and water conservation, forest rehabilitation and
restoration of degraded soil, as well as environmental protection of water bodies
from effluent contamination and garbage decomposition. John Greenfield (New
Zealand) giving a historical perspective of ‘Advance of scientific research on
vetiver system’ traced the rediscovery of the versatile VS, from realization of
vetiver hedges to mark out farm boundaries in Karnataka (India), to the World
Bank-supported follow-up studies on grass biodiversity vis-à-vis its multifarious
applications in phyto-remediation, reclamation of mine dumps, and its ability
to filter toxins before they enter the water-table.
In his opening lecture ‘Vetiver grass –a world technology and its impact on
water’ Richard G. Grimshaw (USA) described how vetiver has developed as a
world technology over four phases of application: soil and water conservation
in poor rural areas; infrastructure stabilization;rehabilitation of difficult and
often polluted sites; and water quality enhancement and site rehabilitation in
relation to industry and intensive agriculture. He admitted that introduction of
VS-based new technology was slow, but it has since made steady progress.
Paul Truong (Australia) in his talk on ‘Vetiver system for water quality improvement’,
dwelt upon the significance of the VS in addressing the imminent
global crisis of water shortage. Pinpointing the ability of vetiver grass to withstand
highly adverse climatic and edaphic conditions, including elevated levels of
salt, acidity, alkalinity, sodicity as well as a whole range of heavy metals, and
also its ability to absorb and tolerate extreme levels of nutrients, he advocated
that vetiver is ideally suited for treating contaminated and polluted wastewater
from industries as well as domestic discharge.
Highlighting morphological and physiological attributes of vetiver supported
with empirical observations, he emphasized that the VS can help manage
wastewater quantity through seepage control, and its quality by trapping sediments
and particles, tolerating and absorbing pollutants, heavy metals, and detoxification
and breakdown of industrial, mining and agrochemical residues, during
land irrigation and under wetland conditions. Through another presentation
he pointed out that vetiver, on account of its trapping/absorption capacity
of nutrients, sediments and agrochemicals, can help stabilize otherwise fragile
drain banks made up of acid sulphate soils highly loaded with heavy metals,
iron, aluminum and other metal concentrations, thus facilitating control of channel
bank erosion. Cameron Smeal (Australia) pointed out that treating effluents with
vetiver in industrial wastewater is actually a ‘recycling process’ and not a treatment
process per se, as in the process of ‘treatment’, the vetiver plant absorbs
essential plant nutrients such as N, P and cations, and stores them for other uses.
In Australia, with large-scale planning this recycling plant is anticipated to provide
high nutrient material for animal feed, mulch for gardens, manure for organic
farming and organic source for composting.
Ralph Ash (Australia) presented an innovative example for development of a
VS prototype for sewerage treatment schemes in Australia. He suggested that
as phyto-remedial technology for effective removal of nutrient loads in sewerage
disposal ponds, vetiver when planted as floating pontoons (Figure 1 i) as well
as on contours, helps reduce nutrient load to a great extent making the sewerage
water suitable for subsequent irrigation purposes3,5. Barbara Hart (Australia)
suggested that septic-tank effluent hydroponic vetiver treatment helps remove
nitrate contamination thus mitigating ground water pollution by septic-tank
effluents. Ian Percy (Australia) showed that landfill leachate run-off, low in
heavy metals but high in salt and nutrients, could be recycled through irrigation
of garbage mounds with vetiver grown thereof, thus saving the adjoining areas
from being contaminated with landfill–leachate discharges. Alison Vieritz (Australia)
showed that vetiver implicit a high nutrient uptake that makes it ideal for
wastewater purification in the effluent irrigation schemes.
Henping Xia (China) based on his findings on constructed vertical flow
wetlands, depicted that vetiver is highly efficient in purification and refinement
of wastewater produced from the oil refineries. He, however, emphasized that
efficiency of vetiver in water refinement was high with the fresh plantation, but
gradually decreased with the passage of time. Thares Srisatit (Bangkok) presented
findings on chromium removal efficiency of vetiver from tannery-wastewater
constructed wetlands, and arsenic removal from experimental pots. Studying
the root growth pattern elucidated through radioactive labeling uptake, Jittiwan
Mahisarakul (Bangkok) showed that the vetiver root could grow luxuriantly
and tolerate contamination of agricultural residues, including endosulphan in the
garbage-fill site. Xuhui Kong (China) showed that vetiver–bamboo floats efficiently
absorb heavy metals such as Zn, Cu, Pb, Hg as well as nitrates from the
wastewater, thus helping the purification of eutrophicated water accumulated on
pig farms. Based on wetland microcosm test Xuerui Lin and Wensheng Shu (China),
from their two independent studies, suggested that vetiver grass-constructed
wetlands have a great potential in the treatment of nitrate-concentrated landfill
leachate and acid mine drainage from lead/zinc mine tailings. Stefanie Wagner
(Germany) showed that vetiver has tremendous capacity for recovering N and P
from wastewater and polluted water loaded with excessive N and P supply,
and can withstand N and P at rates of 10,000 kg/ha/yr and 1000 kg/ ha/yr respectively,
suggesting that vetiver is suitable for treating wastewater and other
polluted materials having high N. Based on analysis of hydraulic retardness,
sedimentation trap and plant submergence characteristics of vetiver hedge
planting, Oscar Metcalfe (Australia) suggested that vetiver hedges significantly
reduce the effective flow area of a channel; dense planting of vetiver in deep unsubmerging
flows show high hydraulic resistance, and rows of vetiver are more
suited to steep slopes/highly erosive flows where sedimentation is unlikely.
Giving an overview of the VS in slope stabilization, Diti Hengchaovanich (Bangkok)
opined that ever since the benchmark experiments on vetiver root strength
conducted in 1996, the VS has evolved to become an important bioengineering
tool having global acceptance. As a follow-up of hard experimental
background, vetiver has made headway in cost-effective stabilization of karst
stony slopes in high-altitude region, as well as in re-vegetation of barren quarried
face in China; river bank stabilization in fresh- and brackish-water environment in
Vietnam and China; beach protection in Senegal; coastal polders stabilization
in Bangladesh, and in providing channel and flood control measures in Australia.
Chengchun Ke (China) provided an experimental account of engineering design
samples for appropriate application of eco-engineering technology for steep
slope and river-bank stabilization, suggesting that in addition to mechanical
characteristics, the root growth curve, three-dimensional root net, capacity to
re-vegetate on slope are the important contributing factors in vetiver eco-engineering
anti-scour and anti-slide applications.
Ping Zhang and Bo Huang (China), through their independent studies, provided
successful examples of quarry/ karst stony slopes re-vegetation using
complex vetiver eco-engineering technique, where vetiver plantations could be
established in mechanically designed planting traps on quarry slopes. Surapol Sanguankaeo
(Bangkok) provided an account of successful application of the VS in
slope stabilization along the mountain roads in the northern, northeastern and
southern regions of Thailand.
Le Viet Dung (Vietnam) showed that establishment of vetiver hedge rows has
provided effective soil-erosion control measure and bank stability in Mekong
river delta against current and wave erosion caused by motorized boats in freshwater,
brackish water, rivers and canals, on alluvial as well as highly acid sulphate
soil. Tran tan Van (Vietnam), through his vetiver trial and demonstration project,
showed that both local farmers and engineers have adopted the VS as their preferred
option for coastal dune and roadbatter stabilization, stream-bank erosion
and fish-pond stabilization. M. Nazrul Islam (Bangladesh) provided a case example
of successful introduction of vetiver in coastal polders over a 87 km long
stretch in Bangladesh, as a cost-effective measure to maintain the coastal embankment
system. O. Bababola (Nigeria) showed that planting of vetiver strips
almost completely checked soil and runoff water loss in the eroded soils and
consistently enriched the protected soil with nutrients. Liyu Xu (China) furnished
case examples where the VS has been found to be effective in agricultural utilization
of red soil, soil and water conservation in orchards, and in advancing tea
growth and tea quality (Figure 1 e).
In addition to the above-mentioned    specific eco-technological applications,
other aspects discussed at the conference included the VS for wasteland reclamation,
agriculture production and agroforestry; adaptability of vetiver to flooding,
medicinal vetiver, pesticidal vetiver, nutritient contents and digestibility of
vetiver grass, the VS entrepreneurship, and other uses of vetiver in cottage industry/

vetiver grass raw material in industrial applications. U. C. Lavania (India) presented
an overall account of vetiver oil, embracing its processing, composition,
economics and perfumery applications.
Seshu Lavania (India) dwelt upon the morpho-anatomical and topographic characteristics
of vetiver root-system to identify root ideotype suitable for need-specific
applications. Y. Vimala (India) presented physico-chemical potential of vetiver in
wetland soil reclamation.
One of the important presentations made at the conference was by Diti
Hengchaovanich (Thailand) about ‘Vetiver victorious: the systematic use of
vetiver to save Madagascar’s FCE railway’. Vetiver plantation could help restore
the 163 km train route in Madagascar,severely hit by over 280 landslides
caused by two cyclones in 2000 (refs 3 and 6). An innovative ‘vetiver-forvetiver
loan/reimbursement’ plan and a ‘modular cropping system’ that facilitated
dissemination and implementation with farmers over a three-year period has
helped establish reduction of erosion damage, strengthening of slopes and infrastructure
along the line. Success achieved by vetiver intervention not only
helped in restoration of the railway line but also improved soil fertility of the
stabilized slopes for aforestation with fruit trees (Figure 1 d). Another successful
example witnessed by the delegates during the conference on the study tour
was the management of 20 ha garbage landfill project site, Datanshan Garbage
landfill, located in Huangpu district, 20 km east of Guangzhou town. Vetiver
plantations along the slopes of the landfill site have not only stabilized the
slopes, but controlled leachate outflow by on-site absorption by vetiver (Figure
1 c). Another demonstration about the potential of the VS in wastewater purification
was in the water streams of Yingzhou ecological park located in Xiaozhou
village, Xinjio town, Haizhu District Guangzhou. Water streams in this ecological
park become severely polluted by tidewater from the Pearl river. Vetiver
plantation in the water channels of the park has helped rehabilitation and purification
of the otherwise contaminated channel water, making it suitable for
growth of natural flora (Figure 1 f and g).
A corollary to such a situation has been observed by the present authors in a
natural ecosystem. A field observation of natural flora of two adjoining ponds with
and without vetiver plantations, shows that the stagnant water in the former is
clean, supporting growth of aquatic plants and in the latter it is eutrophicated,
supporting algal bloom (Figure 1 h).
Although there were no specific recommendations, it was duly emphasized
that the VS has come to an age as a lowcost eco-technology measure for a host
of environmental problems. However, in view of high absorption potential of
vetiver not only for nutrients but also for toxic residues, including agrochemicals,
heavy metals and industrial effluents reaching the upper ground parts, the
question remains as to where to dispose/ make best use of raw material containing
toxic substances. The present authors are of the opinion that as a part
of integrated post-management of the VS eco-technology, it may be appropriate to
utilize the vetiver biomass containing toxic chemicals/substances through its
fixed applications in an eco-friendly manner. The two possible solutions could
be through utilization of such vetiver grass biomass for vetiver ceramic pots
and use of vetiver grass ash as cementreplacement material that meets all environmental
and engineering pre-requisites.
Supporting evidences towards such a utilization were presented separately
by Varunee Thiramongkol and Pichai Nimityongskul (Thailand).
Vetiver is native to India, its environmental applications for soil and water
conservation are in traditional practice since ancient times. Also, systematic
efforts to develop vetiver grass technology for mitigation of soil erosion and
water conservation were first initiated in India, but we missed the due initiative.
Several countries on the other hand, taking cues from the Indian initiative, extensively
implemented environmental applications of this grass. In particular,
Thailand, Australia and China have since made significant strides in applications
and advancement of the VS ecotechnology.
India is the centre of origin of vetiver, where this species is enriched
with tremendous genetic diversity in reproductive behaviour, physiological
and morphological characteristics. Also, natural seed setting in vetiver is known to
be occurring only in India. With concerted efforts exercised, it is possible to
identify/develop designer plant/root types of vetiver suiting specific applications,
ranging from vetiver for its essential oil to vetiver for soil/water conservation and
detoxification. Therefore, it is time that India rejuvenates its initiative and embarks
upon optimum utilization of this low-cost environment-friendly natural
In general, the ICV-3 was well organized.
The first two conferences ICV-1 (1996) at Chiang Rai7 and ICV-2 (2000)
at Cha-am1, both in Thailand were an eye-opener that portrayed bioengineering
potential of vetiver grass. The third one provided the means and ways for environmental
enhancement, more particularly water quality improvement and
mitigation of pollution. In fitness to the progress made, newer avenues opened
for social and economic implications of the VS in future and it was suggested
that ICV-4 be organized on the focal theme ‘Vetiver and people’.
1. Lavania, U. C. and Lavania, S., Curr. Sci., 2000, 78, 944–946.
2. Xu, L., Fang, C., Wan, M. and Chirko, P.(eds) Vetiver System and its Research and
Applications in China, Ya Tai Int. Publ.Co. Ltd, Hongkong, 2003, p. 127.
3. Truong, P. and Xia, H. (eds) Proceedings of the Third International Conference on
Vetiver and Exhibition, China Agricultural Press, Beijing, 2003, p. 614.
4. King of Thailand Vetiver Awards Winners’ papers, ORDPB, Bangkok, Thailand, 2003,p. 58.
5. Truong, P. and Hart, B., PRVN Tech. Bull.
No. 2001/2, ORDPB, Bangkok, Thailand,2001, p. 24.
6. Hengchaovanich, D. and Freudenberger,K. S., PRVN Tech. Bull. No. 2003/2,
ORDPB, Bangkok, Thailand, 2003, p. 16.
7. Lavania, U. C. and Sharma, J. R., J. Med.Aromat. Plant Sci., 1996, 18, 322–326.
U. C. Lavania*, Central Institute of Medicinal and Aromatic Plants, Lucknow
226 015, India; Seshu Lavania, Department of Botany, Lucknow University,
Lucknow 226 007, India and Y. Vimala,Department of Botany, C.C.S. University,
Meerut 250 005, India.
*For correspondence.
e-mail: lavania@cimap.res.in

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