M, J. Obiora1, E. E. Ehirim2, Maurice. Ekwulo3, J. M. Mbaba4,
Investigating the effect of Using Cow Dung and Water Leaf on Bioremediation of Crude Oil Polluted Soil
Abstract
This study investigated the use of fresh Talinum triangular (Water-leaves) and fresh cow dung for bioremediation of crude oil-polluted soils. Water leaves and cow dung were used as bio-stimulant for remediation of crude oil polluted soil. The physicochemical properties of the soils before and after pollution were analyzed. Also, the Total Heterotrophic Bacteria count (THB) and Total Petroleum Hydrocarbons (TPH) content were analyzed every 7 days for 35 days. The results obtained from the physicochemical analysis showed that there was an increase in the pH of the soils after contamination, while there were decreases in the soils’ moisture content, total organic carbon, total nitrogen, and phosphorus contents, which differ remarkably from the control samples, implying that the water leaves and cow dung treatments after pollution were effective. Also, as time and treatment weights were increased, the percentage degradation of TPH in the soil increased. Thus, the 150g weight samples exhibited the best performance on the 35th day, consistently demonstrating superior efficacy across various soil types. Waterleaf treatment outperformed Cow dung treatment in terms of TPH percentage degradation. Specifically, 150g Waterleaf treatment resulted in degradation percentages ranging from 81.27% to 89.50%, while Cow dung treatment achieved percentage of 72.24% to 86.88%. Further examination of TPH degradation rate constants and half-lives for Waterleaf and Cow dung treatments revealed distinct patterns. Waterleaf treatment displayed higher degradation rate constants (ranging from 0.0043 to 0.057 day^-1 for Cow dung and 0.0043 to 0.0509day^-1 for Waterleaf), corroborating its superior TPH removal efficiency. Half-life analysis indicated that Cow dung required more time for TPH to degrade to half its initial concentration, while Waterleaf treatment exhibited faster degradation. Conversely, the variation of Michaelis-Menten constants showed no clear pattern. In terms of model performance, the first-order kinetic rate model demonstrated better congruence between experimental TPH concentrations and the Michaelis-Menten equation.
Keywords: Soil, Hydrocarbon, Remediation, Cow Dung, Water-leaves and kinetic models.
