“Discuss Bioremediation and factors affeting the use of Bio-remediation”
The factors that directly impact on bioremediation are energy sources (electron donors), electron acceptors, nutrients, pH, temperature, and inhibitory substrates or metabolites. One of the primary distinctions between surface soils, vadose zone soils and groundwater sediments is the content of organic material.
Each of the factors discussed above may limit the use of bio remediation in specific circumstances. All the factors are positive in some cases where bio remediation technology has been successfully completed. Knowledge of the susceptibility to bio degradation of some contaminants is still lacking and toxicity testing is becoming more important. Many reports indicate that bio remediation of petroleum hydrocarbons can lead to reduced toxicity and have been taken as evidence of favorable biochemistry in these cases.
There are many factors that limit bio availability and have the impact of slowing the transport of specific compounds into aqueous phase where biological up take occurs readily. The importance of bio availability is strongly dependent on the nature of the contaminant,the soil chemistry, and the matrix. In some cases, bio-availability is relatively unimportant, while in others it may be critical. The influence of site-specific bio availability on bio remediation must be considered.
Bio activity includes consideration of those parameters that have long been recognized as influencing the rate of bio remediation. With current bio remediation configurations, only certain parameters can be manipulated. This suggests that certain sites may be particularly favorable for in situ strategies, because the bio activity may be easily maintained.
US environmental regulations are complex; the rule promulgation process can often be slow. Intense congressional and public involvement may hinder the writing of regulations which reflect in the field experiences. Rapidly emerging technologies, such as bio remediation, have been delayed by governmental policies that support only proven technologies. The trend is slowly changing and for bio remediation using both indigenous and non-indigenous, naturally occur-ring microorganisms, the regulatory hurdles are de-creasing.
Even with the obstacles discussed above, there are tremendous market opportunities for bio remediation.With the next 10 years, soil clean-up costs alone are estimated to exceed US dollar 30 billion in Europe(Caplan, 1993). This compares with the US dollar 1billion spent thus far. If just 5% of this soil is cleaned using bio remediation, 1.5 billion dollars could be earned through bio treatment methods. Reff