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Biosolutions
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In spite of well-demonstrated successes, bioaugmentation – the use of specialized microbes to clean and restore soil or groundwater contaminated by organic chemicals- remains somewhat controversial. There are two primary reasons for this: (1) the “ubiquity principle,” which states that bacterial species capable of degrading contaminants are already present in the soil, hence using biotechnology is unnecessary and unproductive; and (2) previous use of the “ubiquity principle” as a justification to pollute, because “nature will take care of it.” Both statements are true, in the long run, but according to John Maynard Keynes, "In the long run we are all dead." The ubiquity principle is analogous to saying you can build a house anywhere because carpenters and other construction workers are everywhere. If you think about it, you see the flaws in this statement. The required workers are not "literally" everywhere. In some cases they will come to the worksite (if it is close to where they live and the right incentives are provided) and in other cases you will have to provide transportation (to isolated sites). You may also want to choose the types of workers, rather than settle for what is available in order to get the type of house you want! The required construction materials may be provided as well. In many cases the indigenous bacterial population may be too small (like trying to find construction workers in the Sahara desert), may lack the ability to breakdown the contaminants completely and efficiently (like asking a carpenter to build a house out of mud bricks) or may lack the proper conditions for growth (like trying to build a frame house without lumber). Thus, biodegradation might take too long or may incompletely degrade the contaminants (possibly forming undesirable by-products). This is especially possible for many sites where preliminary detailed soil and groundwater characterization is not economically feasible. Many studies have documented poor degradation of contaminants like petroleum in pristine environments even when the environment could be considered ideal for growth of bacteria. The more polluted a site and the longer it has been polluted, the greater the likelihood that it contains bacteria capable of cleaning it up!
A certain amount of additional opposition is due to the view, common among the general public, that all “germs” are bad. Opposition to the use of bioaugmentation to help clean up after the Exxon-Valdez disaster centered around the advisability of introducing “non-indigenous” bacteria into the environment. In reality, bacteria are present in the air, soil and water that are transported by people, cargo and the wind freely everyday. Every commercial item (not to mention people and other living things) transported is covered with bacteria and other microbes. However, we strictly control those items which have a high probability of bringing in pathogenic or otherwise harmful organisms. How can we be confident that bioaugmentation will do no harm? All of the species commonly used for bioaugmentation are widely distributed in nature and can be found in nearly every country. All of the strains currently used for bioaugmentation are selected from nature for their adaptation to degrade various contaminants while living in soil or water, screened to make sure they are safe, and then grown in quantity. There is no genetic engineering involved, and when the microbial food supply of contaminants is depleted, the bacterial ecosystem in the soil or water reverts to its former condition. Furthermore, bacteria that are adapted to live in soil or water are inherently poorly adapted to live in humans, animals and plants (most pathogens are highly adapted specifically to allow them to by-pass their host’s defenses). Microbes selected for bioaugmentation are similar to a hardy variety of wheat that might be imported from another country. We generally know the characteristics of wheat and are not afraid that importing wheat will result in undesirable consequences. The particular strain of wheat, however, may have important benefits such as resistance to disease or ability to grow faster.
The good news is that the great majority of organic compounds are biodegradable. Even recalcitrant mixtures of compounds, such as polychlorinated biphenyls (PCBs), can be broken down by stepwise degradation, first using anaerobic microbial processes or chemical treatment and then an aerobic mixed microbial population, each member of which performs its own dissection of a PCB molecule or its breakdown product. The bad news is that there is no “magic in a can.” While there are a wide variety of microbial products available specifically designed to degrade various classes of compounds, from gasoline to dioxins, none will work without creating the proper conditions. Bioremediation is a lot like farming; the process requires nutrients, an organic substrate on which to grow, a capable microbial ecosystem, a proper range of temperature, moisture and pH, and in most cases oxygen. These conditions can often be created with minimum effort. For example, one of the most popular methods of decontaminating gasoline-tainted soil is pile it in windrows, spray it with water, a microbial product and nutrients, and turn it regularly to provide aeration. In a few months, or even less, contamination will have dropped to below regulatory limits, or even to undetectable levels. The process is considerably more environmentally sound than transferring the soil to a secure landfill.
Other bioremediation processes are more complex, but still very cost-effective, if not the only viable method for decontamination of large areas. A large site contaminated with orthochlorophenol and dioxin required the drilling of extraction wells to withdraw groundwater, installation of a treatment plant to degrade the compounds, using selected and adapted strains of bacteria, and use of pumps to return the clean water to the ground to repeat the cycle. Some sites may require the use of biodegradable surfactants for hydrophobic contaminants in the soil, or the use of air sparging to extract large quantities of volatile organics from groundwater before treatment. Bioscience, Inc. is one of the few companies to offer a wide range of bioremedial technologies, world-class, field-tested MICROCAT ® microbial and adjunct chemical products, analytical instruments for testing biodegradability, in-house laboratory process screening and scale-up testing capability, and field process monitoring and troubleshooting services. (Request the Qualification Package) The company (including its predecessors) also has one of the longest track records in bioaugmentation for spill cleanup, beginning in the early 1970s with decontamination of remote shoreline sites in Scotland and Chile. It has been involved with on-site biodegradation of fuel spills, gasoline, phenol, creosote, orthochlorophenol, steel mill sludge, crude oil, and a wide variety of mixed organic chemical wastes, and has conducted laboratory and respirometric biodegradability studies on many other organic compounds. (Request the 254 Form) Bioscience has a large library of case studies involving bioremediation. Some of these are posted on the web site, while others are available only in hard copy. If you are interested in bioremediation of a certain compound or compounds that do not appear on the site, please contact us.
In a press release dated July 28,2003, we announced a new formulation to help restore the productivity of soils depleted by irrigation, over fertilization, pesticide use, and construction activity (topsoil stripping, earthmoving, and restoration) Low levels of saprophytic bacteria in depleted soils can result in poor turf and crop growth since bacteria are required to convert both inorganic and organic matter to nutrients usable by plants. The new product, MICROCAT®-AG soil conditioner, provides a uniform microbial starter culture to improve soil microbial activity resulting in improved physical characteristics, tilth and productivity. It is especially well suited for use by golf courses.
Supplied as a fine powder, MICROCAT®-AG can be mixed with water for spraying on depleted soils, or used as an admixture in horticultural products, soil amendments, and slow release organic fertilizers to insure excellent microbial activity at the point of use. The saprophytes selected for the new product are natural, non-pathogenic varieties adapted to a wide range of temperatures, and can be applied to soils with a pH from 6 to 9.
The Water Environment Federation's annual exhibition and conference is fast approaching and is set for October 11-15 at the Los Angeles Convention Center. Along with our MICROCAT® LINE of microbial products for waste water treatment, we will be displaying our BI-2000® Laboratory Respirometer known as the "The ideal tool for flexibility, proven reliability and long-term precision in biodegradation and biodegradability studies" Visit us at Booth 4927. We also will be participating in workshop W119, "Using Respirometers for Better Design and Operation of Biological Wastewater Treatment Plants". Click on the previous link for a complete workshop description. We sincerely hope to visit with you as we have many exciting developments to share. Please visit the WEFTEC'03 website for more networking opportunities and registration!
We have 2 new versions of the GEL
Powerpoint presentation - one in and, don't forget... Application guides are available in Adobe Acrobat format on the Bioscience Inc. web site. Links can be found on the MICROCAT® Products Page or, click here and bookmark the link.
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