Assisted bioremediation tests on three natural soils contaminated with benzene

Authors : Maria Manuela CARVALHO, Maria Cristina VİLA, Cristina Delerue MATOS, Maria Teresa Oliva TELES, António FİÚZA

Pages : 153-160

Doi:10.18393/ejss.2015.3.153-160

View : 26 | Download : 7

Publication Date : 2015-07-15

Article Type : Research Paper

Abstract :Bioremediation is an attractive and useful method of remediation of soils contaminated with petroleum hydrocarbons because it is simple to maintain, applicable in large areas, is economic and enables an effective destruction of the contaminant. Usually, the autochthone microorganisms have no ability to degrade these compounds, and otherwise, the contaminated sites have inappropriate environmental conditions for microorganism’s development. These problems can be overcome by assisted bioremediation insert ignore into journalissuearticles values(bioaugmentation and/or biostimulation);. In this study the assisted bioremediation capacity on the rehabilitation of three natural sub-soils insert ignore into journalissuearticles values(granite, limestone and schist); contaminated with benzene was evaluated. Two different types of assisted bioremediation were used: without and with ventilation insert ignore into journalissuearticles values(bioventing);. The bioaugmentation was held by inoculating the soil with a consortium of microorganisms collected from the protection area of crude oil storage tanks in a refinery. In unventilated trials, biostimulation was accomplished by the addition of a nutrient mineral media, while in bioventing oxygen was also added. The tests were carried out at controlled temperature of 25 ºC in stainless steel columns where the moist soil contaminated with benzene insert ignore into journalissuearticles values(200 mg per kg of soil); occupied about 40% of the column’s volume. The processes were daily monitored in discontinued mode. Benzene concentration in the gas phase was quantified by gas chromatography insert ignore into journalissuearticles values(GC-FID);, oxygen and carbon dioxide concentrations were monitored by respirometry. The results revealed that the three contaminated soils were remediated using both technologies, nevertheless, the bioventing showed faster rates. With this work it was proved that respirometric analysis is an appropriate instrument for monitoring the biological activity.
Keywords : bioremediation, bioventing, respirometry, soils, benzene