Oil Sludge Landfarming Biodegradation Experiment Conducted At a Tropical Site in Eastern Venezuela

Abstract

Although climatic conditions are optimal for biodegradation processes to occur, little attention has been given to the application of oil sludge landfarming methods in tropical regions. Here, partial results of our landfarming operations are described for a tropical site in eastern Venezuela, an area characterized by intense oil exploitation and low agricultural productivity. Experiments were carried out in an area of 1 ha and incorporated eight separate treatment plots, including harrowing, water irrigation, fertilization, microbial inoculation or combinations of these. Results showed that total crude oil biodegredation rates of the sludges were stabilized within 6-9 months, with a mean total hydrocarbon degradation of 80%. Saturated hydrocarbon fraction degradation rates were significantly lower (overall slope t-tests P<0.001) in treatments where aeration (harrowing), watering and fertilization were applied, contributing the most to microbial activation of site-specific soil and sludge. The effectiveness of each method was also evaluated by comparison with "control" crop yields. These results are part of the efforts by INTEVEP, S.A., to search for new management disposal alternatives best suited to tropical conditions.