Bioremediation technologies are one of the novel methods in the field of waste and environment management and are presently gaining immense credibility for being eco-compatible. Bioremediation using microbes has been well accepted as an environment friendly and economical treatment method for disposal of hazardous petroleum hydrocarbon contaminated waste (oily waste). Besides this, earthworms can be used to extract toxic heavy metals, including cadmium and lead, from solid waste from domestic refuse collection and waste from vegetable and flower markets. Other novel methods used recently for treatment of wastes are plasma incineration or plasma assisted gasification and pyrolysis technology. The technologies applied for conditioning include ultrasonic degradation, chemical degradation, enzyme addition, electro-coagulation and biological cell destruction. Genetic engineering is another method for improving bioremediation of heavy metals and organic pollutants. Transgenic plants and associated bacteria constitute a new generation of genetically modified organisms for bioremediation.
Top1. Introduction
It is believed now that wastes are no longer treated as waste and they can be used as a valuable resource. Biomass can interact and confront with water and soil pollutants in both active (live) as well as passive (dead) way, thereby offering numerous opportunities of exploring them for environmental clean-up. With rapid increase in urban populations particularly in the developing world, there is a growing problem of how to manage organic waste and to find alternatives to landfill disposal particularly for domestic food waste and that from vegetable markets. According to the research team, it is an unfortunate fact of life that much of this waste is currently dumped on the outskirts of many towns and cities and is causing serious pollution, disease risk and general ecological harm. It also represents a considerable wasted resource, whereas the organic matter might be exploited usefully in growing food crops (Glazer & Nikaido, 2007). Besides this, vast number of pollutants and waste materials containing heavy metals are also disposed into the environment per annum. Approximately 6 x 106 chemical compounds have been synthesized, with 1,000 new chemicals being synthesized annually. Almost 60,000 to 95,000 chemicals are in commercial use. According to Third World Network reports, more than one billion pounds (450 million kilograms) of toxins are released globally in air and water. The contaminants causing ecological problems leading to imbalance in nature is of global concern. Bioremediation is an option that offers the possibility to destroy or render harmless various contaminants using natural biological activity. As such, it uses relatively low-cost, low-technology techniques, which generally have a high public acceptance and can often be carried out on site (Vidali et al., 2001). Compared to other methods, bioremediation is a more promising and less expensive way for cleaning up contaminated soil and water (Kamaludeen et al., 2003). Bioremediation uses biological agents, mainly microorganisms, e.g. yeast, fungi or bacteria to clean up contaminated soil and water (Strong et al., 2008). It results in the elimination, attenuation and/or transformation of polluting or contaminating substances by the use of biological processes.