Dynamics of the estructure and activity of microbial comunities during the composting of weatheres hidrocarbons-contamined soil

MORELLI I.S; DEL PANNO M.T; COPPOPTELLI B.M.; CORAZZA M.S.; IBARROLAZA A.; HARIYO D.D.; LOVISO C.L.; LÓPEZ A.M.; MADUEÑO L.; NEGRÍN M.; PESSACQ J.; DALLO M.G.; TORRES VILAR C.

Messina, Italia

Simposio; 14th Internacional Biodeterioration and Biodegradation Simposium; 2008

The composting of soil contaminated with hydrocarbons has received increased attention as an ex-situ bioremediation technology. This work presents the results obtained in a field-scale study to assess the effects of different aeration and mixing conditions on the dynamics of microbial communities and hydrocarbons degradation in the composting bioremediation process of weathered hydrocarbons-contaminated soil at a location owned by Repsol YPF in Malargüe, Mendoza Argentina. Two 200m3 biopiles consisting of hydrocarbon contaminated soil, goat manure and sawdust were prepared. Two treatments were carried out using aeration as the variable condition. The first used periodical mechanical mixing (defined as BV), whereas the second applied blower aeration via perforated pipes situated at the bottom of the biopile (defined as “BA). The samples were taken monthly during 4 months. Three composite samples representing the surface, middle and bottom of the biopile were analyzed at each time. The number of culturable heterotrophic bacteria (R2A-agar), aliphatic hydrocarbon degrading bacteria (NMP) and PAH degrading bacteria (MPN) were performed. Microbial activity dynamics was assessed by means of enzymatic activities (dehydrogenase, phosphatase, urease and lipase). Physiological profiles of the microbial communities were analyzed using BIOLOG® ECOplate and genetic diversity using PCR-DGGE. Unambiguous differences were found in genetic and physiological diversity of the microbial communities of the two treatments. Treatment of biopile “BV” provoked a stimulatory effect on enzymatic activity of soil compared to biopile “BA”. These results are consistent with the greater hydrocarbons elimination obtained with the “BV” treatment.