Bioremediation of urban soils contaminated with oil by-products - case study Cuenca, Ecuador

Abstract

In Ecuador and several Latin American countries, the degree of contamination of urban soils by hazardous waste from petroleum derivatives is a matter of great concern, because according to the Environmental Protection Agency of the United States explains that a gallon of used lubricating oil contaminates a million gallons of water, the same that meets the needs of fifty people per year [1]. When oil is spilled on the land, it causes infertility in the soil because the used oil contains hydrocarbons that cause the death of the soil and transforms the vegetation into inert. Despite the existence of legislation regulating the use, storage, processing and treatment of waste, there are very few efficient methods that guarantee adequate environmental management of urban soil, either because they are technically complex or economically unfeasible. The objective of this research is to technically and economically evaluate the bioremediation of urban soils contaminated with petroleum derivatives in the city of Cuenca, Ecuador, using Pseudomonas bacteria. There are different methodologies and methods for soil remediation, the technique used for the recovery of soils contaminated with petroleum hydrocarbons in this research was bioremediation, through the application of an association of Pseudomonas bacteria obtained from the same soil, a technique called bio augmentation, and applied in three different concentrations and on the four soil samples obtained from the mechanics of the city of Cuenca. The Pseudomonas bacteria obtained, especially aeruginosa and fluorescence, demonstrated in the experimentation that they have the property of degrading hydrocarbons derived from petroleum, by feeding on carbon compounds in an exponential manner. For the calculation of the remediation cost-benefit, the value of the benefit acquired is divided by the remediation cost found. If the value is higher than the unit, the relation presents benefits; the relation obtained is 5.077, allowing to establish that the remediation process studied is economically viable. It is concluded that the method used is adequate and does not alter the soil with the introduction of foreign bacteria to it, in addition, the method studied serves for the remediation of soils contaminated with non-volatile petroleum hydrocarbons. The cost of its implementation is economically viable.