Abstract

The use of the extract obtained as a leaching of the coconut fiber (Cocos nucifera) as a biostimulant for the remediation of a savanna soil contaminated with heavy oil was evaluated. Through standardized procedures, the main characteristics of the extract, oil and soil were obtained. The soil was contaminated with 100 mL of heavy oil per kilogram. Four experimental units of 1 kg each were established, leaving the first as a pattern without treatment and 3 treated with extract in proportions of 50, 100 and 150 mL, each with 3 replicates distributed at random. The units were left under controlled laboratory conditions and the percentage of oils and fats and the pH were determined every 7 days by means of the EPA 9071b and ASTM D4972 standards, until complying with the Venezuelan standard Decree 2635. It was concluded by means of a Factorial ANOVA analysis, that both the volume of extract applied and the exposure time exert a statistically significant influence on the percentage of oils and fats and the pH with 95% confidence level. All soil units treated with extract reached the limit value established in Decree 2635 at 28 days.

Abstract

Wastewater from car washers and lubricators contain high levels of hydrocarbons. These are discharged into the public sewer system without proper treatment and not complying with the regulations. In this study was evaluated the process of bioremediation of total hydrocarbons in Puyango’s wastewater, using bioaugmentation treatment, which means, applying hydrocarbons-degrading microorganisms. First, a characterization of the wastewater was carried out, and the content of total petroleum hydrocarbons (TPH) and the flow rate was determined for seven days. A mixture of bacteria: Acinetobacter sp., Pseudomonas sp. y Mycobacterium sp was applied in solid form (80 g tablet) with a minimum concentration of 4 x 108 CFU / ml soluble in water, using 2 tablets during 30 days of treatment. The concentration of the TPH was determined weekly, plotting the temporal variation and quantifying the % of removal. The results indicate that the technique of bioaugmentation was effective (p = 0.003) in the removal of the TPH, obtaining percentages above 86 %. The time of greatest removal of TPH was obtained in the third week of treatment with 92 %. In addition, COD removals were obtained –40 %, Oils and fats - 50%, Surfactants –43 % thus fulfilling the current regulations for discharge to the public sewer system for the TPH.