There are trade offs and exceptions to every engineering problem
In order to consider bioremediation you first must isolate and recognize the hazardous material. This is usually done with expensive test equipment, but there are a few companies who will analyze a sample for a minimal fee. Once the the number of hazardous wastes in the sample are known (including heavy metals) you can check the feasibility of process, are their microorganisms that can oxidize or reduce the material, in a cost effective manner. Are those organism cost effective? Can they be pathogenic to humans or wildlife? More than not bioremediation is applicable for hydrocarbons and chlorinated solvents.
Waste treament processes
Since the fifties refineries have used used microbes to oxidize their process waste streams. One simple system that is commonly used is the activated sludge. Microbes can also be used to denitrify or desulphurize materials. A new type of process equipment for activated sludge is the rotary bioreactor. For major soil contamination, an in-situ process must be used. One way to stimulate underground degradation is an innoculant injection system, or a methane injection system. This is done to stimulate the growth of methanotropic bacteria which will break down the contamination.To see a methane injection system see this site. For shallow ground contamination, an aerobic bioremediation is used. Basically an oilphillic fertilizer can be applied to soil that has been aerated, to stimulate the growth of the naturally occuring oil eating microbes in the soil. Temperature, pH, porosity, amount of water, and amount of contaminant all affect the growth of the microbes. For high level of contamination, an innoculant of microbes can be used since the microorganism will not reach a growth stage in a high toxicity environment. Another solution to this problem is to add more soil so that the contamination is diluted, and the microbes will reach growth stage. For more info on shallow remediation go to Oettco Bioremediation products.
The pollution degrading microbes
It may be a morbid thought, but microbes degrade us when we die, and they break down most organic material so that there is a carbon cycle. Two main species of bacteria are used in bioremediation, pseudomonas and methantrops. Pseudomonas, are mostly aerobic and like to oxidize alkanes and aromatics. For more information on pseudomonas click here. Bacteria can adapt to ecosystem by producing an induced enzyme, this enzyme can break down certain carbon sources. Energy is realeased when the bacteria breaks the bonds of the carbon source, to see an oxidation of phenol by an aerobic pseudomona, hit the hotword.
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