The Effect of Phenol on Heterotrophic Ammonia-Oxidizing Bacteria in Soils and Wastewaters

Nitrification is an important biological process in soils which, ammonia convert to nitrite and subsequently to nitrate, oxidation of ammonia accomplish by Autotrophic and Heterotrophic oxidizer bacteria. In this study, Heterotrophic oxidizer bacteria enumerated in two soil and wastewater samples with different characteristic and displayed that heterotrophic nitrifers in soil samples were higher than number of those in wastewater samples. Different pollutants have effects on nitrification process, one of these are phenol that inhibitor for this process. Phenol is pertaining to poly aromatic hydrocarbons which are toxic chemical material for human and another organism. Add phenol with different concentrations to media of ammonia oxidizer bacteria and investigated decrease of ammonia removal percentage and percentage of nitrite product in soil and wastewater samples. This decline in ammonia removal and nitrite product was surveyed in heterotrophic nitrification. The percentage of elimination ammonia in soil samples were about 67.9 % in the absence of phenol and decreased to about 47.5% in 32 ppm phenol. The percentage of ammonia elimination in wastewater samples were about 91.3 % in the absence of phenol and decreased to about 71.6% in 32 ppm phenol. In soil samples was separated to two heterotrophic ammonia oxidizer bacteria, single and double rod with gram-positive test, this separation was because of vivid decreasing of ammonia removal percentage and in wastewater samples separated bacteria were gram-positive double rod and gram-positive cocci. Heterotrophic ammonia oxidizer bacteria in soil sample were had low resistance to phenol than heterotrophic ammonia oxidizer bacteria in wastewater samples and decreased the ammonia removal percentage in lesser phenol concentration.