Influence of activated sewage sludge amendment on PAH removal efficiency from a naturally contaminated soil: application of the landfarming treatment

Abstract

The removal of polycyclic aromatic hydrocarbons (PAHs) from a naturally co-contaminated soil by PAHs and heavy metals with an initial concentration of 620 mg of total PAHs kg dry soil was investigated. The efficiency of landfarming in removing phenanthrene, pyrene, benzo(a)pyrene and the group of total 16 US EPA PAHs was evaluated. The process was biostimulated by adding centrifuged activated sewage sludge (SS) as an organic amendment. The tested ratios of contaminated soil to SS were 1:2, 1:1, 1:0.5 and 1:0 as wet weight basis. The process performance was monitored through chemical, microbiological and ecotoxicological analyses during 105 days of incubation. The results of analyses demonstrated that the treatment without centrifuged SS achieved a significantly higher total 16 US EPA PAH removal efficiency (i.e. 32%) compared to treatments with amendment. In the same treatment, the removal efficiency of the PAH bioavailable fraction was 100% for phenanthrene, benzo(a)pyrene and the group of total 16 US EPA PAHs, whereas 76% for pyrene. Ecotoxicity test performed with bioluminescent bacteria Vibrio fischeri confirmed the effectiveness of landfarming. Finally, the results showed that indigenous microorganisms under certain and controlled operating conditions have greater potential for PAH biodegradation compared to allochthonous microorganisms.

Co-application of activated carbon and compost to contaminated soils: toxic elements mobility and PAH degradation and availability

“…The reason might be that the degradation of PAH is mainly carried out by bacteria, which are effective to degrade low molecular weight (LMW) PAH but whose potential to degrade HMW-PAH is limited (García-Delgado et al 2015b). In addition, the high PAH degradation efficiency achieved in the unamended soil likely occurred due to the ability of indigenous microbial community to adapt to the actual polluted environment and degrade targeted contaminants (Lladó et al 2015;Lukic et al 2016;Lukić et al 2017). Degradation of PAH was previously described in an unamended soil due to the high degradation of LMW-PAH, despite unappreciable degradation of 4-and 5,6-rings PAH (Lukić et al 2017).…”

A sustainable approach to enhance heavy hydrocarbons removal in landfarming treatment

“…Landfarming represents one of the most commonly applied treatments for ex-situ bioremediation due to its relatively simple implementation and operation (Lukić et al 2017 ). This technology involves the spreading of a thin layer of contaminated soil (50–60 cm) on a treatment area, where it is being aerated or turned over to ensure aerobic conditions inside.…”

“…The most studied bioaugmentation practice consists of the addition of pure or mixed culture of petroleum-degrading bacteria (Grace Liu et al 2011 , 2013 ; Wu et al 2016 ; Haleyur et al 2019 ; Zhou et al 2019 ). Nonetheless, a non-selected consortium of microorganisms present in waste materials can represent a more feasible option for real-scale applications being easier to obtain and to manage and more adaptable to the complex environmental conditions of contamination (Fernández-Luqueño et al 2016 ; Lukić et al 2017 ). Additionally, the employment of waste material accomplishes circular economy principles since a new option of reuse is provided instead of its final disposal.…”

Bioaugmentation process for PAHs contaminated soil remediation through microbial inocula from anaerobic treatment of lignocellulosic substrate

“…According to this, several approaches have been implemented for the remediation of PAHs contaminated soils. For instance, bioremediation techniques have been widely investigated by testing several operational conditions such as various temperature values, different nutrients and/or carbon source addition, aerobic or anaerobic condition, involvement of indigenous or allochthonous microbial/fungal community (Lukić et al, 2017). In particular, a growing specific scientific interest is focused on the involvement of anaerobic condition as well as inoculation of ligninolytic species due to their capability to produce feasible enzymes for PAHs oxidation.…”