Bio Hydrocarbon Remediation
Hydrocarbons in whatever form are generally the most common contaminant that requires remediation due to their widespread occurrence and the risks they pose to humans, ani- mals, environmental and all living organisms.
Total Petroleum Hydrocarbons (TPH) is a term used to describe hydrocarbon compounds derived from Petroleum Sources. Common fuels such as Petrol, Diesel, Kerosene and Lu- bricating Oils/Greases all fall within the TPH banner. Due to the diversity of compounds that comprise TPH and the environmental and human health risks they pose, the remedial methods used to address them need to be considered on a site-specific basis.
Although hydrocarbons are simple organic substances (comprising only carbon and hy- drogen) there are a huge number of different compounds, each exhibiting different chemi- cal and physical properties. To rationalise the behavior of TPH once released into the envi- ronment it is easiest to look at the structure and size of specific compounds. TPH com- pounds that have an aliphatic structure.
(i.e. straight or branched chains of carbon mole- cules) will behave differently to aromatic compounds (ringed chains of carbons). Similarly TPH compounds that have less carbon molecules will also act differently.
Lighter end TPH compounds (i.e. less than 16 carbon atoms) tend to be more mobile due to greater solubility, greater volatility and lower organic partitioning coefficients. Lightweight aromatic compounds, such as benzene, are also more toxic making them of greater con- cern if released into the environment. Heavier TPH compounds typically have opposing properties, tending to adsorb into the organic fraction of soil. Heavier aromatic compounds, referred to as Polycyclic Aromatic Compounds (PAH), can also have higher toxicity and are typically more persistent in the environment. PAH's are commonly found in coal tar, heavy oils and creosotes.