Environmental Biotechnology Syed Abdullah Gilani

Waste generation is a side effect of consumption and production activities that tend to rise with the level of economic value. Wastes arise from domestic and industrial activities e.g., sewage, waste waters, agriculture and food wastes from processing, wood wastes and an ever increasing range of toxic industrial chemical products.

Cost for proper dealing with wastes are escalating and much attention is presently devoted to efficient and effective waste management which will include costs of collection, storage, processing and removal of wastes. Environmental biotechnology is the application of recognized biotechnology processes for the protection and restoration of the quality of the environment especially with a long term perspective. It relies on microbial consortia of complex and variable composition.

Environmental biotechnology includes application of biological systems and processes in waste treatment and management and processes for the protection and restoration of the quality of the environment. Many successful biotechnological processes have been developed for water, gas, oil and solid waste treatments.

Waste water and sewage treatment Waste water and sewage were treated using biological treatment systems ranging from cesspits, septic tanks and sewage farms to gravel beds, percolating filters, and activated sludge processes coupled with anaerobic digestion. Such system relies on microbial populations for their efficiency.

Solid waste management There are several strategies available for solid waste management. These are: Primary recycling or selecting from the waste stream materials for direct re-use e.g., metals. Secondary recycling by mechanical re-use e.g., glass. Tertiary recycling – incineration Landfilling: In this procedure, solid wastes are deposited in low-lying low value site and each day’s waste deposit is compressed and covered by a layer of soil.

Compositing which is an aerobic microbial driven process that converts solid organic wastes into a stable, sanitary, humus-like material that has been considerably reduced in bulk and can be safely returned to the environment. Bioremediation It is the use of either naturally occurring or deliberately introduced microorganisms to consume or break down environmental pollutants.

It is not a new technology It is not a new technology. Human have relied on biological processes to reduce waste materials for thousands of years. In bioremediation, microbes can convert chemicals into harmless compounds either through aerobic or anaerobic metabolism. Both types of processes involve oxidation and reduction reactions.

At many sites, bioremediation involves the combined action of both aerobic and anaerobic bacteria to decontaminate the site fully. The most common and effective metabolizing microbes used for bioremediation are indigenous microbes which are those naturally found at the polluted sites eg., Pseudomonas bacteria.

Stimulating bioremediation Scientists use many strategies to assist microorganisms in their ability to degrade contaminants depending on the microorganisms involved, the environment site being cleaned up and the type of chemical pollutants that need to be decontaminated.

These stimulating strategies are: Nutrient enrichment (fertilization) is done by adding fertilizers to contaminated environment to stimulate the growth of indigenous microorganisms that can degrade pollutants. Bioaugmentation (seeding) is done by adding bacteria to contaminated environment to assist indigenous microbes with biodegradative process.

There are two types of bioremediation. These are: 1. Ex-situ bioremediation: usually chemical materials are removed from the contaminated site to another location for treatment. 2. In-situ bioremediation: usually cleaning up is done at the contaminated site without removal to another location.