Crude oil degradation in loamy soil using Neem root extracts: An experimental study

Abstract

The biodegradability of Total Petroleum Hydrocarbon (TPH) in loamy soil amended using neem root extracts was investigated in this study. The neem roots were soaked separately into predetermined volume of water to extract liquids
from the roots. The solution of neem-water and extract was then used as treatment to remediate crude oil polluted loamy soil. The loamy soil was used for this study. The physicochemical properties of the loamy soil before pollution,
after pollution and at the 84th day of treatment were determined, while analysis for the total bacteria count and TPH were carried out for 84th days at 14 days interval. Density, electrical conductivity (EC), moisture content (MC), total
organic carbon (TOC), total nitrogen (TN) and phosphorus (P) in the soils increased after pollution, except for pH, which was the opposite. However, density, EC, MC, TOC, TN and P decreased remarkably with time under treatment, while pH increased from acidity to neutrality after the treatments. The total bacteria count increased across the soils with treatments up to the 56th day of analysis, but declined gradually thereafter due to depletion of the nutrients in the loamy soil. The degradation of TPH in the loamy soil decreased across the process, but higher in the loamy soil with treatment. However, TPH removal was higher with treatment in water solution with performed of neem extract. The TPH degradation percentage at the 84th day was determined and the response thus observed was promising for the degradation of pollutant in soil.