4.1.2. Geophysical, geochemical and biological characteristics of the contaminated site

Soil structure contains different textures ranging from low to high contents of sand, silt and clay. A granular and well-structured soil can facilitate effective delivery of air, water and nutrients to the microorganisms for in situ bioremediation.

Moisture content (water) is the primary factor in determining the dielectric constant of soil and other mediums. Soil moisture content generally ranges from 25 to 28 %.

pH (power of hydrogen) ranges from 5.5–8.0, which is the optimum range for the growth of microbes and to destroy the contaminants.

Temperature ranges from 15–45 ^oC. Temperature affects biochemical reaction rates and the rates are double for each 10 ^oC rise in temperature.

Oxygen is mainly used for the initial breakdown of the hydrocarbon in the contaminated sites. The amount of available oxygen will determine whether the bioremediation is carried out under aerobic or anaerobic condition.

Microbial diversity exists in the contaminated site such as Pseudomonas, Aeromonas, Flavobacteria, Chlorobacteria, Corynebacteria, Acinetobacter, Mycobacteria, Streptomyces, Bacilli, Arthrobacter, Aeromonas, Cyanobacteria, and etc.

Macrobenthos diversity is consortium of aquatic plants such as Eichornia crassipes, Salvinia molesta, Ceratophyllum demersum and is consortium of aquatic animals such as Anodonta woodiana and Limnodrilus hoffmeisteri which have high potential to degradation of turbidity, biochemical oxygen demand, chemical oxygen demand, ammonia, nitrite and nitrate in domestic wastewater.