Soil polluted by waste motor oil: remediation by biostimulation

Abstract

Soil impacted by waste motor oil (WMO) inhibits microbial activity for recycling the basic elements of life an affecting negatively its fertility. Biostimulation is a way to recover soil by eliminating WMO at a value lower than 4400 ppm permitted by an environmental rule called NOM-138-SEMARNAT/SSA1-2012. The aim of this research was the biostimulation of soil polluted by WMO in different in depending ways with the mineral solution (MS), or vermicompost (VC) with Phaseolus vulgaris o green manure (GM). Recovering soil was determined by the production of CO2 from WMO´s oxidation, by measuring the WMO oxidizing bacterial population (WMOOB) and WMO´s concentration by Soxhlet; experimental data were analyzed with standard Tukey-error. The results showed that biostimulation of soil impacted by 17000 ppm of WMO with MS decreased it until 4386 ppm, but better biostimulation with VC which reducing WMO until 3766 ppm in 6 months, both values lower than the maximum accepted by the NOM 138, and statistically different compared to soil BIS by P. vulgaris or GM with 8596 ppm of WMO and the 17000 ppm of WMO from soil non-BIS or negative control. This concludes that biostimulation could be specific depending on hydrocarbon´s complex as WMO was eliminated by MS and VC according to NOM-138 for recovering soil´s fertility.

Keywords

• soil
• wmo
• biostimulation
• microbial population
• mineralization
• nom-138.