Biotechnological Techniques of Waste Management and Limitations of Bioremediation
Author: Cornelius Onye Nichodemus
The environment of man has been polluted by wastes which are as results of his activities (economically and socially). These wastes are so unwanted that if not managed properly, affects man's health, ozone layer, degrade the environment, reduce industrial activities etc. In order to put an end to the above mentioned and safe man and his environment, waste management is applied to mitigate the adverse effects on man and his environment. Waste management is therefore the process of treating both liquid and solid waste. Examples of solid wastes are agricultural wastes, garbage, rubbish, dead animals, industrial solid waste, mining and mineral wastes etc while examples of liquid wastes are sewage and various industrial effluents.
Furthermore, solid waste can be divided into biodegradable (organic) materials and non-biodegradable (inorganic) materials. Biodegradable solid wastes are acted upon by aerobic and anaerobic bacteria hence they are broken down biologically e.g agricultural materials while non-biodegrade solid wastes are not broken down biologically e.g mining and mineral materials.
These wastes can be toxic or hazardous to man and his environment and one of the best approaches to be used in order to reduce its effects is through biotechnological techniques.
Some of the biotechnological techniques includes;
1. ACTIVATED SLUDGE: this is the process of treating sewage and waste water in an aerobic environment using biological agents such as bacteria and protozoa. This system removes pathogenic microorganisms waste water. A typical activated sludge system has four components; an aeration tank, a settling tank (clarifier), a return sludge pump and a system for introducing oxygen into the aeration tank.
2. BIOFILTRATION: this is the treatment technology in water and waste water purification. It is a pollution control method using a bioreactor containing living materials to capture and biologically degrade pollutants. Other uses of biofiltration include processing waste water, macrobiotic oxidation of contaminants in air etc.
3. BIOSORPTION: this is the uptake of both metal and non-metal species by biomass whether living or denatured. This process helps to remove metal species from aqueous solutions by microbial biomass.
4.BIOREACTOR: is a device or apparatus in which living organisms especially bacteria synthesize useful substances or breakdown harmful ones such as sewage.
5. BIOLEACHING: is the process of using microorganisms such as bacteria to dissolve metals from their ores instead of using chemical solutions. Example of such metals dissolved through bioleaching are; nickel, copper, cobalt, lead, zinc etc. Bioleaching operates using specific bacteria that can extract the metal contents out of their ores.
6. COMPOSTING: is a process in which microorganisms degrades waste at high temperature. During this process, the microbes release heat and increase the temperature which leads to more solubility of waste and higher metabolic activity in the composts. Composting is usually done at temperature above 55oC.
7. PHYTOREMEDIATION: this is the direct use of green plants for in situ removal or degradation of contaminants in soils, sludge, sediments and ground water. Phytoremediation as a branch of bioremediation uses different mechanisms in degrading contaminants and they are; Rhizosphere biodegradation, Phyto-stabilization, Phyto-accumulation, Phyto-volatilization, Phyto-degradation etc. Some of the plants that are used for phytoremediation are Brassica juncea, Salix species, Poplar tree, Sorghastrum nutans (Indian grass), Sunflower (Helianthus annuus) etc.
LIMITATIONS OF BIOREMEDIATION
Bioremediation is faced with common environmental limitations to which is related to hazardous chemical wastes which pisses high waste concentrations and its toxicity. Sometimes, this toxicity either inhibits the growth of microorganisms or kills them. That is, for efficient growth of microorganism it requires favorable pH condition, sufficient amount of mineral nutrients and the required maximum amount of temperature required by microbes. Another limitation is that degradation of some wastes are host specific that is inoculation with specific microorganisms. Other factors that also affect bioremediation are solubility of waste, nature and chemical composition of waste and it's microbial interaction.
In conclusion, in as much as bioremediation which is a branch of biotechnology has contributed immensely in mitigating waste in man's environment hence making it environmental friendly. It is also faced with limitations which needs improvement.
About Author / Additional Info:
I am a First Class graduate of plant Science and biotechnology from University of port Harcourt, currently pursuing my masters in plant biotechnology.