Biodiesel bioremediation in soils may occur by natural attenuation or by engineered techniques, such as biostimulation and bioaugmentation. The present study evaluated the degradation of biodiesel in two soils with di...Biodiesel bioremediation in soils may occur by natural attenuation or by engineered techniques, such as biostimulation and bioaugmentation. The present study evaluated the degradation of biodiesel in two soils with different particle size characteristics by the bioremediation processes of natural attenuation and biostimulation. The experiment was carried out ex situ, with the factors temperature, moisture content, and pH being controlled for the experimental period of 110 days. The study aimed at evaluating the biodegradation of a clayey soil （A） and a sandy soil （B）, both contaminated with pure biodiesel, by using the analytical methods of respirometry and gas chromatography. Biostimulation treatments using nitrogen, phosphorus, and potassium solutions （NPK） promoted higher microbiological activity in both soils. At the end of the experiment, it was observed that biostimulation was more efficient when compared to natural attenuation, showing higher biodiesel degradation for both soils A （59.76%） and B （90.41%）.展开更多
The possibilities of combining the dissolution of short-range-order minerals （SROMs） like allophane and imogolite, by ammonium oxalate and a particle size distribution analysis performed by the pipette method were i...The possibilities of combining the dissolution of short-range-order minerals （SROMs） like allophane and imogolite, by ammonium oxalate and a particle size distribution analysis performed by the pipette method were investigated by tests on a soil sample from Reunion, a volcanic island located in the Indian Ocean, having a large SROMs content. The need to work with moist soil samples was again emphasized because the microaggregates formed during air-drying are resistant to the reagent. The SROM content increased, but irregularly, with the number of dissolutions by ammonium oxalate： 334 and 470 mg g-1 of SROMs were dissolved after one and three dissolutions respectively. Six successive dissolutions with ammonium oxalate on the same soil sample showed that 89% of the sum of oxides extracted by the 6 dissolutions were extracted by the first dissolution （mean 304 mg g-l）. A compromise needs to be found between the total removal of SROMs by large quantities of ammonium oxalate and the preservation of clay minerals, which were unexpectedly dissolved by this reagent. These tests enabled a description of the clay assemblage of the soil （gibbsite, smectite, and traces of kaolinite） in an area where such information was lacking due to the difficulties encountered in recuperation of the clay fraction.展开更多
文摘Biodiesel bioremediation in soils may occur by natural attenuation or by engineered techniques, such as biostimulation and bioaugmentation. The present study evaluated the degradation of biodiesel in two soils with different particle size characteristics by the bioremediation processes of natural attenuation and biostimulation. The experiment was carried out ex situ, with the factors temperature, moisture content, and pH being controlled for the experimental period of 110 days. The study aimed at evaluating the biodegradation of a clayey soil （A） and a sandy soil （B）, both contaminated with pure biodiesel, by using the analytical methods of respirometry and gas chromatography. Biostimulation treatments using nitrogen, phosphorus, and potassium solutions （NPK） promoted higher microbiological activity in both soils. At the end of the experiment, it was observed that biostimulation was more efficient when compared to natural attenuation, showing higher biodiesel degradation for both soils A （59.76%） and B （90.41%）.
基金Supported by the Center for International Cooperation in Agronomic Research for Developmentthe French Ministry of Overseas Departments and Territories+1 种基金the European Agricultural Guidance and Guarantee Fundthe Regional Direction of Environment,France
文摘The possibilities of combining the dissolution of short-range-order minerals （SROMs） like allophane and imogolite, by ammonium oxalate and a particle size distribution analysis performed by the pipette method were investigated by tests on a soil sample from Reunion, a volcanic island located in the Indian Ocean, having a large SROMs content. The need to work with moist soil samples was again emphasized because the microaggregates formed during air-drying are resistant to the reagent. The SROM content increased, but irregularly, with the number of dissolutions by ammonium oxalate： 334 and 470 mg g-1 of SROMs were dissolved after one and three dissolutions respectively. Six successive dissolutions with ammonium oxalate on the same soil sample showed that 89% of the sum of oxides extracted by the 6 dissolutions were extracted by the first dissolution （mean 304 mg g-l）. A compromise needs to be found between the total removal of SROMs by large quantities of ammonium oxalate and the preservation of clay minerals, which were unexpectedly dissolved by this reagent. These tests enabled a description of the clay assemblage of the soil （gibbsite, smectite, and traces of kaolinite） in an area where such information was lacking due to the difficulties encountered in recuperation of the clay fraction.
