Biostimulation of Petroleum-Contaminated Soils with Synthetic and Natural Sources of NPK Fertilizer

Soil contamination with petroleum hydrocarbons has imposed drastic damages to plant, animal, and human life, leading to the development of various remediation technologies. However, the implementation of these methods is often difficult or requires a long time. In this study, the performance of synthetic (salts) and natural (sawdust, cow manure, and hen manure) sources of nitrogen:phosphorus:potassium (NPK) fertilizer was compared in the biostimulation of petroleum-contaminated soil, by measuring the total petroleum hydrocarbon (TPH) reduction after 28 days, via gas chromatography (GC). Four types of isolates with the potential for hydrocarbon degradation were identified and characterized based on morphological and biochemical tests. The results showed more efficiency of natural sources compared to synthetic sources, as a TPH reduction of 84.4, 81.9, and 79.7% was obtained by adding 4 wt.% of hen manure, cow manure, and sawdust, respectively. The analysis of variance (ANOVA) of the designed experiment for the synthetic sources showed the NPK of 1275:497:112 as the optimum ratio and the N and K as the most effective elements. The finding of this study can pave a way for proving the high efficiency of natural waste materials as a cost-effective and simple method, for bioremediation of petroleum hydrocarbon soils.