Evaluation of the effects of inorganic and organic fertilizers and activated carbon on bioremediation of soil contaminated with weathered crude oil

Abstract

ABSTRACT:The objective of this study was designed to evaluate the effects of nutrients (inorganic NPK fertilizer and organic fertilizer) and adsorptive amendment agents (activated carbon) as well as their interactions on bioremediation of soil contaminated with Weathered Crude Oil (WECO). The organic fertilizer was made up of cattle dungs, pig dungs and poultry droppings mixtures. Box Behnken Design (BBD) of Response Surface Methodology (RSM) with three levels and three factors was used having inorganic NPK fertilizer (3 -5 g), activated carbon (20 -40g) and organic fertilizer (30 -50 g) as independent variables and percentage WECO degradation as dependent variable (response) in a four weeks remediation period. Results of the study showed that WECO removal rate in soil is invariably dependent on the amount of nutrient and adsorptive agents. The optimum amount of nutrient and adsorptive amendment agents obtained to achieve a predicted maximum WECO removal of 66.24% are: inorganic NPK fertilizer, 4.19 g; activated carbon, 35.42 g and organic fertilizer, 48.94 g. At this predicted optimum amount, validation experiment revealed that 65.55% of WECO removal was achieved. Statistical analyses revealed the closeness of the experimental results to model predictions which thus show the reliability of the quadratic regression model. Therefore, organic and inorganic nutrients as well as adsorptive amendment alone and/or in combination enhances soil indigenous microbial density and activity which thereby accentuates petroleum hydrocarbons biodegradation and subsequently reduces the period of bioremediation and remediation cost.

Adsorptive bioremediation of soil highly contaminated with crude oil

“…Positive influence of GAC and biochar was demonstrated in recent short investigations (2-4 weeks) where those adsorbents amendment accelerated TPH biodegradation in Nigerian soils spiked with 5 or 10% weathered crude oil treated through bioactivation (Ameh et al, 2013;Agarry et al, 2015;Agarry, 2018). Formation of microbial biofilm communities on GAC in treatment of oil sands was shown positively affected petroleum degradation (Islam et al, 2015).…”

Kinetics of bioremediation of crude oil polluted soil using potato peels as bio-stimulant

“…The model estimated the biological half-life (t1/2) as the time taken for half of its original amount to be converted. Half-life was evaluated using the model in equation ( 6) (Agarry, 2013;Agarry et al, 2013).…”

Microbial Populations of Agricultural Soil Polluted With Crude Oil

“…"Soils are complex mixtures of minerals, water, air, organic matter and countless organisms that are the decaying remains of once-living things" [1]. "The Natural Resource Conservation Service (NRCS) defines soil as a natural body comprised of solids (minerals and organic matter), liquid, and gases that occur on the land surface, occupy space, and are characterized by one or both of the following: horizons, or layers, that are distinguishable from the initial material as a result of additions, losses, transfers, and transformations of energy and matter or the ability to support rooted plants in a natural environment" [2].…”