Approximately 30,000 m3 of contaminated soil recovered from cleanup operations after a 29,000 barrel oil spill in the Desaguadero River (January 2000) was stored in temporary pits. Waste disposal plans explored several options for final disposal, including incineration and land farming. Initial concerns about the ability to landfarm the contaminated soil centered on the biodegradation potential at altitudes of 14,000 ft (4,300 m) and in a region with seasonally low day and nighttime temperatures. The Bolivian Altiplano has a semiarid climate where daily fluctuations of 15°C in temperature are common while average temperatures range between −6 C (July) and 21.0°C (November).
The technical experts at the Bolivian Ministry of Sustainable Development were reluctant to grant permission for Land Farming to be used at high altitude and instead insisted that all the contaminated soil be sent by truck across Bolivia to lower altitudes where the proposed a Land Farm was to be created. As an operational response a series of experiments was set up to demonstrate that indeed Land Farming was possible at high altitude. This paper presents the results of these experiments but it should be clearly noted that the testes were conducted under operational conditions without the rigour normally found in laboratory or scientific experiments.
Results showed that it was not only possible to deplete the total petroleum hydrocarbon (TPH) content from 40,000 ppm to below 1,000 ppm required by Bolivian law, but that it also could be completed within 4 months under specific technical conditions of the biodegradation process. Previous studies documented the formation of oil-mineral aggregates (OMAs) in the contaminated soils from the Rio Desaguadero spill1. We hypothesized that OMA formation and presence of aluminum polysilicate would provide an effective combination to increase the biodegradability of the soils under specific control conditions. This paper explains the high-altitude biodegradation process and the results of monitoring tests from the land farming under operational field conditions.
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* Transredes S.A. Carratera Antigua a Cochabamba Kilómetro 7 Santa Cruz. Bolivia.