Examination of Microbial and pH Contribution of Azadirachta Indica Leaf on Crude Oil Degradation in Soils

Abstract

The effectiveness of pH and microbial activities on the sun-dried and room-dried Azadirachta Indica leaf was monitored to examine the significance of their roles in crude oil degradation in different soil environments.The examination was conducted by varying quantities, in the remediation of sandy and loamy soils contaminated with 100ml of crude oil. Gas Chromatography-Mass Spectrometry method was used to test for the physicochemical properties of the materials used for the experiment. The unpolluted loamy soil was observed to contain pH of 6.75, electric conductivity of 10.36µS/cm, Total Oxygen content of 2.99%, Total Nitrogen of 0.091%, potassium content of 36.82942%, phosphorus content of 15.36% and Total Bacteria count of 2.15×10²cfu/g. Likewise, The unpolluted sandy soil was observed to contain pH of 6.82, electric conductivity of 21.48µS/cm, Total Oxygen content of 1.18%, Total Nitrogen of 0.036%, potassium content of 24.03681%, phosphorus content of 5.18% and Total Bacteria count of 1.86×10²cfu/g. The inoculant was prepared by blending sun-dried and room-dried Azadirachta Indica leaf. A range of 50g, 60g, 70g, 80g, 90g and 100g of blended Azadirachta Indica leaf were applied on the polluted soils for 35 days and significant reduction of the pollutants was achieved. The highest remediation was observed in soils treated with 100g room dried Azadirachta Indica leafs. 96% remediation occurred in sandy soils treated with 100g room dried Azadirachta Indica leafs as TPH depleted from 35818.69mg/kg to 1349.109mg/kg and 92% remediation occurred in loamy soil treated with 100g room dried Azadirachta Indica leafs as TPH depleted from 48508.92mg/kg to 3977.739mg/kg

Key words: Examination, microbial, pH, contribution, Azadirachta Indica Leaf, crude oil, degradation, soils