Bioremediation
Bioremediation is the use of living organisms — primarily microorganisms such as bacteria, fungi, and algae — to degrade, neutralise, or remove toxic contaminants from soil, water, and air. It exploits natural metabolic processes to convert hazardous substances like petroleum hydrocarbons, heavy metals, chlorinated solvents, and pesticides into less harmful compounds. As a cost-effective and eco-friendly alternative to physical or chemical remediation methods, bioremediation is widely used at contaminated industrial sites, oil spill zones, and wastewater treatment facilities.
Types of Bioremediation and Their Applications
| Type | Organisms Used | Target Contaminants | Typical Site | Timeframe |
|---|---|---|---|---|
| In situ bioremediation | Bacteria, archaea | Petroleum hydrocarbons, BTEX | Underground aquifers | Months–years |
| Ex situ (land farming) | Soil bacteria, fungi | Diesel, PAHs | Excavated soil plots | 6–24 months |
| Phytoremediation | Hyperaccumulator plants | Heavy metals (Pb, Cd, As) | Mine tailings, farmland | 1–10 years |
| Mycoremediation | White-rot fungi | Dioxins, PCBs, oil | Forest soils, spill sites | 3–18 months |
| Biostimulation | Indigenous microbes | Nitrates, chlorinated solvents | Groundwater plumes | 6–36 months |
| Bioaugmentation | Introduced specialised bacteria | TCE, PCE solvents | Industrial brownfields | 1–5 years |
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Related Terms
Eutrophication
Eutrophication is the process by which a water body becomes overly enriched with nutrients — primarily nitrogen and phosphorus — leading to excessive growth of algae and aquatic plants, depleting dissolved oxygen, and causing the death of fish and other aquatic organisms. It most commonly results from agricultural runoff, sewage discharge, and industrial effluents that introduce nutrients into lakes, rivers, estuaries, and coastal zones. The subsequent algal blooms block sunlight, and when the algae die and decompose, microbial respiration consumes oxygen, creating hypoxic or anoxic "dead zones."
Acid Rain
Acid rain refers to any form of precipitation — rain, snow, fog, or dry deposition — with a pH lower than 5.6, resulting from the dissolution of sulphur dioxide (SO₂) and nitrogen oxides (NOₓ) in atmospheric moisture to form sulphuric and nitric acids. These pollutants are primarily emitted by coal-burning power plants, vehicle exhausts, and industrial smelters, and can travel hundreds of kilometres before depositing. Acid rain damages forests, acidifies lakes and soils, corrodes buildings and infrastructure, and harms aquatic biodiversity.
Sustainability
Sustainability is the capacity to meet the needs of the present generation without compromising the ability of future generations to meet their own needs, as defined in the 1987 Brundtland Commission report "Our Common Future." It integrates three interconnected pillars — environmental protection, social equity, and economic development — often referred to as the triple bottom line. In practice, sustainability science guides policy, urban planning, corporate strategy, and resource management to ensure long-term viability of human and ecological systems.
From Greek "bios" (life) and Latin "remedium" (cure, remedy) — "re" (again) + "mederi" (to heal). The term emerged in environmental engineering literature in the 1970s–1980s following major oil spills and industrial contamination events, gaining mainstream use after the Exxon Valdez oil spill in 1989.