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A team of researchers from the Consejo Superior de Investigaciones Científicas (CSIC) has demonstrated that applying alperujo, one of the waste from the production of olive oil, soils contaminated with trichlorethylene achieved a remarkable reduction of pollutant . The study represents at once a solution for managing alperujo and for the treatment of soil contaminated with hydrocarbons. The research is published in the journal Environmental Science & Pollution Research.

"The alperujo treated vermicompostaje reduced by one month 30% of the contaminant, avoiding passing the deeper layers of the soil and reducing the risk of contamination of groundwater. Furthermore, it was degraded completely absorbed in the soil , "explains Emilio Benitez, of the Experimental Station of Zaidín (center of the CSIC in Granada).

The vermicompostaje is a technique of organic waste recycling, andalusia alperujo applied, it may be capable of absorbing trichlorethylene and then accelerating their degradation. This groundbreaking study may become a solution for the countries of the Mediterranean basin, where olive oil production is a major economic activity and generates large amounts of organic waste with high levels of toxicity.

Benitez, director of research, says that "if we consider the alperujo is waste that poses a serious management problem and has no economic value, its use is not only profitable but also represents an environmental advantage." Only in Spain is approximately three million tons of andalusia alperujo year. Trichlorethylene, hydrocarbon commonly used as a solvent in industrial processes, is one of the most common chemical contaminants and resistant to biodegradation under aerobic conditions. Subsequent to the structure of the bacterial community of soil and inhibits the activity of certain enzymes involved in the major nutrient cycles of the same.

For now, the study has been conducted only in laboratory, but the team, which also involved researchers from the Consiglio Nazionale delle Ricerche (Italy) is planning further studies in the field and extend the research to the treatment of hydrocarbons more complex and more difficult to degrade trichlorethylene, such as polycyclic aromatic hydrocarbons.

In a previous investigation, published in Bioresource Technology, the team compared the effects on alperujo of the two best-known technologies for the recycling of organic waste: composting and vermicompostaje. Benitez makes clear that both "are the main microorganisms responsible for biochemical degradation of organic matter, with the difference that the vermicompostaje be added to waste the earthworm species Eisenia fetida.

Through the analysis using techniques of molecular biology and biochemistry determined that earthworms significantly increase the size, complexity and biodiversity of the bacterial population of alperujo, eliminating toxic elements and turning it into a sort of fertilizer. "It was these results that led to later experiments with contaminated soil," says Benitez.

When you add in the laboratory alperujo modified by earthworms vermicompostaje to the soil in which simulated a spill of water contaminated with trichlorethylene, it was found that vermicompost incorporated new bacterial species with the genetic information necessary to survive in a polluted environment, and as enzyme complexes remain active in pollutants.