Description
Biological Remediation
Biological treatment and reliance on bacteria is not new or novel; it has played a central role in
conventional waste treatment throughout the history of mankind. What is new however, is our growing
understanding of the natural processes and how we can utilize bacteria for industrial, agricultural and
residential applications in breaking down organic waste thereby enhancing the bio-degradation process
fundamental to natural recycling and sanitation clean-ups. Bioremediation consists mainly of
biostimulation, where nutrients or oxygen are added to soil or water to stimulate native bacteria a, and
bioaugmentation, where select microorganisms, naturally occurring or engineered strains, are
introduced to enhance the degradation process. The primary use of biological agents has been in
enhanced natural remediation and wastewater treatment of sanitation systems for residential and
municipalities, lakes, rivers and ponds, once through lagoons for agricultural and industrial activated
wastewater systems. Bioremediation can usually be done in situ, without the need for existing system
modification and saving large upfront capital cost in waste treatment equipment. Bioaugmentation, t he
purposeful inoculation of external microorganisms to a biological system with sufficient population of
suitable types of bacteria will dramatically improved results where biostimulation alone has proven
inadequate or ineffective. In order to understand the growing use and evolution of bioremediation, we
need to understand in simple terms the biological function of bacteria (prokaryotes) and consider their
role in the balance of nature. “If there is food, some organism will eat it. If there is a place to live, some
organism will live there. Every species has a great ability to produce offspring and its population expands
until it runs out of food or it is limited by competition, its own waste products, or some other factor.
Changes in climate or introduction of a new species from elsewhere can greatly affect the existing
balance of nature.” This simple statement summarizes the interactions of all living things on Earth.
Bacteria are single-cell organisms and most of t hem must find foods such as sugars, proteins and
vitamins-nutriments to live. The various metabolic capabilities of bacteria are the key traits that we use
to group and classify them into their genera/ sub-species. The ecosystem, both on land and in the water,
depends heavily upon the activity of bacteria. The cycling of nutrients such as carbon, nitrogen, and
sulfur is completed by their ceaseless labor. Organic carbon, in the form of dead and rotting organisms,
would quickly deplete the carbon dioxide in the atmosphere if not for the activity of decomposers. This
may not sound too bad to you, but realize that without carbon dioxide, there would be no
photosynthesis in plants, and no food. When organisms die, the carbon contained in Solving
Environmental Problems Naturally Since 1976 392 t heir tissues becomes unavailable for most other
living things. decomposition is the breakdown of these organisms, and t he release of nutrients back into
the environment, and is one of the most important roles of the bacteria. The cycling of nitrogen is
another important activity of bacteria. Plants rely on nitrogen from t he soil for their health and growth,
and cannot acquire it from the gaseous nitrogen in the atmosphere. The primary way in which nitrogen
becomes available to them is through nitrogen fixating bacteria. These bacteria convert gaseous
nitrogen into nitrates or nitrites as part of their metabolism, and the resulting products are released into
the environment. Some plant s, such as liverworts, cycads, and legumes have taken special advantage of
this process by modifying t heir structure to house the bacteria in their own tissues. Other denitrifying
bacteria metabolize in the reverse direct ion, turning nitrates into nitrogen gas or nitrous oxide. When
colonies of these bacteria occur on croplands, they may deplete the soil nutrients, and make it difficult for
crops to grow. Bacteria are also used in sewage treatment facilities. Solid matter, after having been separated
from liquid wastes by screens and shredders, are added to a group of anaerobic prokaryotes. These bacteria
decompose the material, converting it to material that can be used as landfill or fertilizer in land farming.
Bacteria are also used in solving environmental problems because of their selective capability to consume
and degrade almost any compound. For instance, certain cultured bacteria are now being sprayed on oil spills
and petroleum drilling lagoons, where they rapidly multiply and break down the oil molecules into less toxic
compounds. In a similar way, bacteria can also clean up old mines. The water from old mines is
filled with highly acidic heavy metals that are highly toxic and expensive to clean up. However,
there is an increasing use of bacteria, especially a genus called Thiobacillus, which thrives in
acidic water. These microbes can extract copper from the wat er, and other valuable metals,
utilizing oxidize-sulfur to accumulate and extract the metals. These are just two examples of the
ways that bacteria can be practically used to solve environmental problems, and over-time
many more applications will be developed through selective breeding and mixed production of
various bacteria cultures.
