Phytoremediation Report Executive Summary

Introduction. Phytoremediation is the use of plants, including trees, grasses and aquatic plants, to remove, destroy or sequester hazardous substances from the environment. It is an emerging technology for environmental remediation that offers promise as a low-cost, versatile technique suitable for use against a number of different types of contaminants in a variety of media.

Phytoremediation Technologies. Several different types of phytoremediation are being used commercially, or are in advanced stages of research and development. Some applications rely simply on plants' ability to accumulate large quantities of certain contaminants ("phytoextraction") or to take up and transpire large amounts of water from the soil and groundwater (creation of hydraulic barriers). Contaminants can also be removed from aqueous wastestreams by absorption onto plant roots ("rhizofiltration"). In other applications, the contaminants are degraded or metabolized within the plant ("phytotransformation"), sometimes coupled with volatilization into the air from plant biomass ("phytovolatilization"); in other applications, contaminants are degraded in the soil by the action of secreted plant enzymes (in one form of phytotransformation) or by plant stimulation of microbial biodegradative activity ("phytostimulation"), or contaminants are immobilized in the soil by plant exudates ("phytostabilization").

Phytoremediation Applications
Soil	Water
Phytoextraction	Rhizofiltration
Phytostabilization	Hydraulic Barriers
Phytostimulation	Vegetative Caps
Phytovolatilization	Constructed Wetlands
Phytotransformation

Plant Species Used in Phytoremediation. A variety of naturally-occurring and specially-selected plant species are used in phytoremediation. A number of terrestrial and aquatic plants are known to be natural hyperaccumulators of metals, but since these tend to be slow growers, researchers have turned to other species, more recently identified or selected, as more promising commercial candidates. Deep-rooted trees such as poplar, willow and cottonwood are most commonly used for applications requiring withdrawal of large amounts of water from the subsurface, while a number of different plants, trees and grasses are used to stimulate microbial degradation of organic contaminants in soil. Among plants at earlier stages of research are plants and trees expressing biodegradative enzymes, halophytic (salt-loving) plants, and plants such as bamboo that are currently used in constructed wetlands.

Contaminants Amenable to Phytoremediation. Phytoremediation is potentially applicable to a diversity of substances, including most of the more prevalent environmental contaminants. Early work involving metal hyperaccumulators focused attention on the technology's applicability to heavy metals and radionuclides. However, phytoremediation has also been demonstrated against other inorganic contaminants like arsenic and various salts and nutrients, and on a variety of organic contaminants, including chlorinated solvents, explosives, petroleum hydrocarbons, polyaromatic hydrocarbons, and pesticides.

Phytoremediation Industry. The U.S. phytoremediation industry consists of at least two dozen companies falling into several different categories. Most visible are the dedicated phytoremediation companies, whose sole or primary remediation technology is phytoremediation, but a related and growing category includes other specialty companies, diversifying into hazardous waste phytoremediation from areas such as constructed wetlands. The next most active segment in the commercial marketplace includes a handful of the large to midsize consulting/engineering firms that have developed an expertise in phytoremediation. Also part of the "industry", although generally not conducting commercial remediations, are several industrial companies, who conduct research for internal needs, and a large number of academic, government, and other non-profit research groups conducting research and developing new technologies.

Industry Trends. Although at an early stage of its growth, the phytoremediation industry appears to be developing similarly to other industry sectors devoted to innovative remediation technologies. The dedicated companies drive much of the innovation, and dominate the market in its early days, but run the risk of seeing the market dominated over time by larger, diversified companies, once the technology is better proven and the necessary expertise more widely disseminated. In phytoremediation's case, competition is also faced from specialty companies such as nurseries, plant breeders, agricultural biotechnology companies and other firms having expertise in plant agriculture, some of which have already begun to show an interest in phytoremediation.

Corporate Strategies. One strategy for companies to pursue to protect their market position would be to develop proprietary, patent-protected technology, such as novel plant varieties, genetically engineered ("transgenic") plants, or proprietary soil additives. However, the research to develop such technologies is time-consuming and expensive, and past experience has cast serious doubt on the ability of the environmental market and its small profit margins to support advanced research, particularly biological research. In spite of such obstacles, we believe that transgenic plants will play an important role in commercial phytoremediation, within the next two to four years.

Field Demonstrations. Phytoremediation has been carried out commercially, or demonstrated at pilot scale, at dozens of sites in the U.S. and, to a lesser degree, other countries. In addition to pilot-scale and commercial projects completed by dedicated phytoremediation firms and consulting/engineering firms, there are a number of demonstration projects underway, many of which are funded or supported by the U.S. federal government. The goals of many of these projects include the generation of economic and technical data to support the efficacy of phytoremediation in specific remediation scenarios.

Factors Governing Market Success. Phytoremediation's market success will be governed by many factors, not least of which are its own strengths and weaknesses. Among its greatest advantages are its low cost (although solid economic data are generally still lacking), the fact that it is a permanent, in situ technology, its applicability to a wide variety of contaminants, and its attractiveness to the general public. Among limitations are that some phytoremediation activities are slower than competing remedial technologies, the limitation of some applications to shallow soils or groundwater, the inherent limitations of biological systems, and regulatory unfamiliarity.

Other Market Barriers. Phytoremediation faces other barriers to market acceptance as well, ones that are common to all innovative technologies. These include the need to prove efficacy and cost-effectiveness to site owners, consultants and regulators, various barriers and biases embodied in environmental laws and regulations that favor traditional technologies over newer ones, and the challenges of the changing climate for remediation in the U.S., where economic factors are replacing regulatory factors as driving forces. However, these obstacles may be mitigated by prospects for regulatory relaxation, and the possibility that the new economic climate may favor low-cost technologies that can address the riskiest portions of contaminated sites. Phytoremediation's growth may also be assisted by a number of government programs for the promotion of innovative technologies.

Potenital Markets for Phytoremediation. Phytoremediation is applicable to a number of hazardous waste and other remedial scenarios, which offer sizable potential markets. Site remediation markets include remediation of organics, metals and radionuclides from soils and water, which together offer a total U.S. market opportunity of $7.2-8.5 billion. Phytoremediation is potentially applicable to the $12-24 billion U.S. municipal wastewater treatment market and the multi-billion dollar industrial wastewater treatment market, including the smaller sectors such as the $500-700 million market for treatment of acid mine drainage and a potential market of $600-1,200 million for control of landfill leachate in the United States. Similar markets exist overseas, which today are smaller but which offer greater long-term potential for growth.

Estimated 1998 Markets for Phytoremediation. The largest 1998 U.S. markets for phytoremediation are for treatment of organic contaminants in groundwater, estimated at $5-10 million, control of landfill leachate, approximately $3-5 million, and remediation of metals from soil, also about $3-5 million. Smaller current markets are for remediation of organics in soil, and organics in wastewater, each estimated at $2-3 million, and radionuclides in soil and groundwater, estimated at $0.5-1 million. In general, the markets involving organic contaminants should see strong, steady growth in the coming years, while the markets involving metals or radionuclides are capable of dramatic growth as the technology's efficacy becomes better established.

Estimated 1998 U.S. Phytoremediation Markets
Organics in groundwater	$5-10 million
Organics in soil	$2-3 million
Metals in groundwater	$0.1-0.2 million
Metals in soil	$3-5 million
Radionuclides	$0.5-1.0 million
Landfill Leachate	$3-5 million
Organics in Wastewater	$2-3 million
Metals in Wastewater	$0.1-0.3 million
Other	$0.8-2.1 million
Total	$16.5-29.5 million
Copyright 1998 by D. Glass Associates, Inc.

Phytoremediation's Growth Potential. We estimate the total U.S. phytoremediation market in 1998 to be $16.5-29.5 million, and that the market will grow to $55-103 million by 2000 and $214-370 million by 2005. Although we have not estimated international markets in this report, we believe these markets should also begin to grow to sizable numbers, particularly in Europe, beginning in the early years of the new century.