Thirty Years and Counting: Bioremediation in Its Prime?

Abstract

Bioremediation in its formal sense, meaning any use of living organisms to degrade wastes, has been practiced since humans first populated the world and had to dispose of their trash. Without knowing about the microorganisms in the soil and water, people relied on them to destroy waste products from human domestic, agricultural, and industrial activities by converting them to carbon dioxide, water, and additional microbial biomass. With the advent of wastewater treatment plants in the late 19th century (Frankland and Frankland 1894), biotreatment became a more formalized, better-engineered process although it still was not called bioremediation. Direct land treatment of residues from waste-water treatment plants, refinery sludges, and municipal wastes, as well as composting, has been practiced widely for several decades. The formal application of this natural technique for treating spills and anthropogenic compounds began 30 years ago with a report entitled Beneficial Stimulation of Bacterial Activity in Groundwater Containing Petroleum Products, by R.L. Raymond and coworkers (1975). The authors reported that by adding nutrients to subsurface soil, they could increase the numbers of bacteria and degrade hydrocarbons derived from petroleum and thereby boost the rate of removal of the contaminants. This was the origin of the process that is now called accelerated or enhanced in situ bioremediation (ISB). ISB can involve the addition of various nutrients, depending on the soil and groundwater chemistry, but most often includes the addition of an electron acceptor (oxygen in some form or nitrate), phosphates, and perhaps a nitrogen source. the process can be applied to subsurface soils or aquifers as well as to to empoundments, lakes, and other bodies of water.