Engineered in situ Bioremediation

Intrinsic bioremediation is satisfactory at some places, but it is slow process due to poorly adapted microorganisms, limited ability of electron acceptor and nutrients, cold temperature and high concentration of contaminants. When site conditions are not suitable, bioremediation requires construction of engineered systems to supply materials that stimulate microorganisms. Engineered in situ bioremediation accelerates the desired biodegradation reactions by encouraging growth of more microorganisms via optimizing physico-chemical conditions (Bouwer et al, 1998). Oxygen and electron acceptors (e.g. NO3 -1 and SO4 2-) and nutrients (e.g. nitrogen and phosphorus) promote microbial growth in surface.

Surface treatment using above-ground Reactor, injection of oxygen, acid nutrient and extraction walls

When contamination is deeper, amended water is injected through wells. But in some in situ bioremediation systems both extraction and injection wells are used in combination to control the flow of contaminated ground water combined with above-ground bioreactor treatment and subsequent reinjection of nutrients spiked effluent are done.