Experimental Investigation of a Pilot-Scale Concerning Ex-Situ Bioremediation of Petroleum Hydrocarbons Contaminated Soils

Abstract

The soil samples were taken from the site of a former oil products depot from an industrial area (Romania). The soil samples taken were analyzed from a physical and chemical point of view: texture, pH, soil micronutrient content, metals concentration and petroleum hydrocarbon concentration (PHCs). The soil contaminated with total petroleum hydrocarbon (TPH (4280 mg kg−1) was disposed in the form of a pile (L × W × H: 3000 × 1400 × 500 mm). Experiments on a pilot-scale were conducted over 12 weeks at constant pH (7.5–8), temperature (22–32 °C), nutrient contents C/N/P ratio 100/10/1, soil aeration time (8 h/day) and moisture (30%). Samples were taken every two weeks for the monitoring of the TPH and the microorganisms content. During the experiment, microorganisms were added (Pseudomonas and Bacillus) every two weeks. Results of the analyses regarding the concentration of PHCs were revealed a linear decrease of the concentration of PHCs after only two weeks of treatment. This decrease in concentration was also achieved in the following weeks. Following the analysis performed on the model at the pilot scale regarding the depollution process, it can be concluded that a soil contaminated with petroleum hydrocarbons can be efficiently depolluted by performing an aeration of 8 h/day, adding microorganisms Pseudomonas and Bacillus to ensure the conditions for increasing in the total number of germs (colony forming units–CFU) from 151 × 105 to 213 × 107 CFU g−1 soil, after 12 weeks of soil treatment—the depollution efficiency achieved is 83%.

Advances in Remediation of Contaminated Sites: Volume I

“…(2) The metal salt or metal oxide is mixed with biomass first, and then the biochar is obtained via biomass pyrolysis. Currently, the metals commonly used for biochar modification are Fe [80], Mg [68,81], and Mn [82,83]. Sun et al [42] demonstrated that Fe-modified biochar could be obtained by adding crushed rice husk to 1 M ferric chloride hexahydrate (FeCl 3 • 6H 2 O), with a mass ratio of 1:25 for Fe 3 + to biomass, and then pyrolyzed at 600 • C. Their field experiments showed that the DTPA-Cd concentration in soil, with the Fe-modified biochar treatment, decreased by 37.74-41.65% compared with that in the control group.…”

“…Their preparation methods could change greatly with the different research materials. For example, Wang et al [83] and others prepared co-existing TiO 2 nanoparticles magnetically modified kaolin by in-situ precision. Mi et al [81] prepared La-modified magnetic composite by co-precipitation.…”

“…Ou et al [80] synthesized magnetic polyoxometalate adsorbents and found that there was a strong hydrogen bond between NH 2 -Fe 3 O 4 and CC/POMNP, which kept the stability of the adsorbent. Wang et al [83] studied the effect of nanometer titanium dioxide (TiO 2 ) on the adsorption and desorption of TC by magnetized kaolin (MK). The results showed that TiO 2 nanoparticles increased the adsorption capacity of TC on MK by 2.02%.…”

“…Previous studies indicated that the xenobiotics biodegradation and metabolism might include the decomposition of plastic polymers and pollutants (e.g., bisphenol, toluene, benzoate, heavy metals and PAHs) [52,53,82,83]. The increase in this metabolic pathway indicated that bacteria in treated soils could use PE or PHE as a carbon source to grow/reproduce and degrade them.…”

Effects of Polyethylene Microplastics and Phenanthrene on Soil Properties, Enzyme Activities and Bacterial Communities

“…Previous studies indicated that the xenobiotics biodegradation and metabolism might include the decomposition of plastic polymers and pollutants (e.g., bisphenol, toluene, benzoate, heavy metals and PAHs) [52,53,82,83]. The increase in this metabolic pathway indicated that bacteria in treated soils could use PE or PHE as a carbon source to grow/reproduce and degrade them.…”