Potential of bamboo in phytoremediation
the portuguese technology

Joris De Vos - COBELGAL Company - Portugal

devos@mail.telepac.pt

VII World Bamboo Congress - New Delhi – India - March 2004

Abstract

Since the early 1970's, constructed wetlands have been engineered specifically for waste water and sludge treatments. Environmental engineers and scientists have learned how to replicate the attributes of natural wetlands into technically working units by controlling depth and flow gradients.
It is reported that more than 1 600 units are in operation in the USA and more than 5000 in Europe (mainly Denmark, Germany, Belgium, France, Austria,..). Many of these systems are designed with specific treatment objectives and have reported operational data that display consistent and predictable performance for meeting permit limitations.
The first commercial constructed wetland is in perfect operation in Germany since 1966.
The use of bamboo in constructed wetlands has been spearheaded by Cobelgal, a Portuguese consulting company active in environmental care technologies.
Since 1990, Cobelgal is active in phytoremediation applying the constructed wetland technology mainly for the treatment of domestic wastewaters. Cobelgal has also been involved in several research projects about bamboo. He was the coordinator of “Bamboo for Europe” the most important integrated research project even realised in Europe about bamboo and co-funded by the EEC.
(Nine partners of five European countries resolving all aspects from the in vitro multiplication to the European marked requirements of industrial applications -December 1996 to May 2000- budget of 1 230 000, 00 Euros.
The replace of the traditional water plants in the constructed wetlands technology by some bamboo species, is one of the results of the project “Bamboo for Europe”... Another major result is the possibility to mix bamboo and wood fibers to improve the quality of MDF (Medium Density Fiberboard).
It is expected that further developments of both results will lead to the treatment of a contamination by the production of a raw material for the industry.

1 – New environment care policy

Health and environmental risks of pollution have become more apparent throughout the world over the past several decades. Contaminants can cause land and groundwater to be unusable and toxic elements can be introduced in the food chain. 
Because of increased public awareness and concern, environmental regulations have been created to not only prevent pollution, but also to remediate areas where contamination has occurred. 

2 – New technologies for the environment care policy

The economic costs of environmental remediation is tremendous and has been the driving factor in the development of new remediation technologies. 
Bioremediation is the systematic use of micro-organisms for environmental contaminant treatment. In this case the contaminants are degraded by introducing amendments - like nutrients or oxygen - for the stimulation of microbe’s activity.
Phytoremediation  is another bio-based low cost alternative technology and represent the systematic use of plants for environmental contaminant treatment. For phytoremediation  to be possible, contaminants must be within the plant’s root zone and must be bio-available.

The four main technologies for phytoremediation are:

- Phytoextraction:
  uses plants to extract contaminants into harvestable parts of the plant

- Phytostabilisation:
  uses plants tolerant to some contaminants to reduce their mobility into soils prevending
  further soil or ground water contamination

- Phytodegradation:
  is a plant assisted bioremediation in which degradation of contaminants occurs during
  plant’s metabolic proces

- Phytovolatilization:
  metals such Selenium, Arsenic and Mercury can potentially be vented to the atmosphere
  through plants after some transformation by microorganisms

3 - Market potential

An American company (D.Glass Associates,2001) specialised in market studies of phytoremediation reported market grow in the USA for the last years:
-          1998: an estimated USA market revenue of 16,6 - 29.5 million dollars
-          1999: an estimated USA marked revenue of 30-49 million dollars
-          2002: an estimated USA marked revenue of 50 – 86 million dollars
-          2005: an estimated USA marked revenue of 235- 400 million dollars
Worldwide the report estimate the 1999 world phytoremediation market to be 34 -38 million dollars, including 1-2 million in Canada and 2-5 million in Europe. The main interest of above mentioned estimations are not the values but the annual market growth.

A study published by the European Community estimate in 1.000.000,00 the contaminated areas all over Europe. The cost estimation for a complete recovering of these areas, by present technologies, is so high that it will never be possible to do it. Only key contaminations (like Tchernobyl) receive some financial support of the EEC. 

Phytoremediation is very near to agricultural practises and is the reason why agricultural equipment constructors (like John Deere) are investing time and money is such market. Phytoremediation is also the cheapest and probably the only solution to resolve the recovering of big contaminated areas. This explains the great deal of research and governmental interest all over the world. 

4 - Phytoremediation applications for Urban wastewaters treatment

The traditional areas of application and research for phytoremediation are linked to the remediation of heavy metals. In 1998, The American Institute of Petroleum (API) published the document” Treatment wetlands for the Petroleum Industry” an excellent summery for the application of this technology in the recovering of areas polluted with hydrocarbons: Texaco, Shell, Armco, BP, Chevron among others are resolving their contamination problem through the constructed wetlands technololgy.

Nevertheless, urban wastewaters and agricultural practises are the major pollution sources of undergroudwaters. Constructed wetlands technology is applied under numerous variations but all of them may be classified under three main alternatives: (figure 1)

1-      The superficial flow of the effluents
2-      The sub – superficial horizontal flow of the effluents
3-      The sub-superficial vertical flow of the effluents

Superficial flow is the classical situation for natural wetlands. They are basically anaerobic systems due to the fact that o² diffusion in water is very low.and is only present at the surface of the wetland.
Vertical and horizontal sub superficial flow systems is the situation for constructed wetlands. They are basically based on an aerobic activity of bacteria’s. The bacteria’s are fixed on the roots of the plants which are able to bring the oxygen from the atmosphere to the roots through air canals situated in the stems of the plants.
The two main inconvenient of constructed wetlands are the area needed for their implementation and the time required to obtain a full efficiency of the unit. The rhizomes of the plants have to cover completely the area of the Wetland what could require between 1 and 2 years.

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