Ex Situ Bioremediation and Oil Spills

Ex-situ bioremediation is a biological process where soil is transported to another location for treatment in which contaminated soil is processed to the natural microbial population. One example is land farming. It’s the simplest form of bioremediation in which the contaminated soil is spread out in layers on a lined treated area. Land farming requires large areas which are not suitable for small sites but are the cheapest form of bioremediation.  





Another example is turned windrows. The contaminated soil is placed into a shaped pile up and is aerated by periodical turning of the windrows by specialized machinery. Organic materials and nutrients are added to the windrows while turning to improve aeration and soil characteristics.  This is the most cost effective method of ex-situ.

Force vented biopiles is another method. The soil is placed into a shaped pile up and aerated either by a vacuum pump or air injection blower system. Vapors from the biopile are collected and treated on-site by granular activated carbon (GAC) or air bio-filter to reduce emissions to the atmosphere. 

Biopiles can be constructed taller than windrows which require less space on site. It’s also the preferred choice if the contaminates are odorous or volatile. Treatment times range from 6 to 16 weeks dependent on contaminant type.

 Some advantages of ex situ bioremediation is it’s suitable for a wide range of contaminants and flexible. There are also limitations. Ex situ bioremediation doesn't work for heavy metal contamination or chlorinated hydrocarbons. It also won’t work for some soils like clay and also like said before, it requires large spaces.