Intensification of ex situ bioremediation of soils polluted with used lubricant oils: A comparison of biostimulation and bioaugmentation with a special focus on the type and size of the inoculum

Attila Bodor, Péter Petrovszki, Ágnes Erdeiné Kis, György Erik Vincze, Krisztián Laczi, Naila Bounedjoum, Árpád Szilágyi, Balázs Szalontai, Gábor Feigl, Kornél L. Kovács, Gábor Rákhely, Katalin Perei

Research output: Article

Abstract

Used lubricant oils (ULOs) strongly bind to soil particles and cause persistent pollution. In this study, soil microcosm experiments were conducted to model the ex situ bioremediation of a long term ULO-polluted area. Biostimulation and various inoculation levels of bioaugmentation were applied to determine the efficacy of total petrol hydrocarbon (TPH) removal. ULO-contaminated soil microcosms were monitored for microbial respiration, colony-forming units (CFUs) and TPH bioconversion. Biostimulation with inorganic nutrients was responsible for 22% of ULO removal after 40 days. Bioaugmentation using two hydrocarbon-degrader strains: Rhodococcus quingshengii KAG C and Rhodococcus erythropolis PR4 at a small inoculum size (107 CFUs g−1 soil), reduced initial TPH concentration by 24% and 29%, respectively; the application of a higher inoculum size (109 CFUs g−1 soil) led to 41% and 32% bioconversion, respectively. After 20 days, all augmented CFUs decreased to the same level as measured in the biostimulated cases, substantiating the challenge for the newly introduced hydrocarbon-degrading strains to cope with environmental stressors. Our results not only highlight that an increased number of degrader cells does not always correlate with enhanced TPH bioconversion, but they also indicate that biostimulation might be an economical solution to promote ULO biodegradation in long term contaminated soils.

Original languageEnglish
Article number4106
Pages (from-to)1-17
Number of pages17
JournalInternational journal of environmental research and public health
Volume17
Issue number11
DOIs
Publication statusPublished - jún. 1 2020

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis

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