Exploring the effect of composting technologies on the recovery of hydrocarbon contaminated soil post chemical oxidative treatment

ANTONIO J. FERNÁNDEZ-GONZÁLEZ; JANINA A. ROSSO; MEDINA, ROCÍO; PABLO J. VILLADAS; MARÍA T. DEL PANNO; FERNANDO M. GARCÍA-RODRÍGUEZ; MANUEL FERNÁNDEZ-LÓPEZ

APPLIED SOIL ECOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2020 vol. 150

0929-1393

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic pollutants that contaminate large areas. They are mainly released to environment by anthropogenicactivities principally due to the petrochemical industry. The low biodegradation rate characteristic of PAHs in aged contaminated soils could be overcome trough thechemical oxidation. In this study, composting with the soil and stimulation with mature compost were the strategies applied in soil microcosms after chemicaloxidation with ammonium persulfate in a PAHs chronically contaminated soil.A 29% of PAHs elimination and an increase of their bioavailability were found after chemical oxidation with ammonium persulfate. Due to the oxidative treatmentthe total bacterial and the gram-positive population PAH dioxygenase genes were significantly reduced and no gram-negative PAHs degraders were detected.The following application of organic amendments produced a higher increase in total bacteria and recovery of the degrading population of GP PAH after one yearof treatment, in comparison with the pre-oxidized soil bioremediation, only promoted by irrigation and aeration. Also a significant increase in the content ofbioavailable PAHs was observed. However, from both composting strategies only the stimulation with mature compost led to a net PAHs removal. Taking intoaccount the residual dissolved total carbon and humification degree (E4/E6 ratio), it was attributed to the preferential consumption of more easily degradablecompounds than hydrocarbons the low removal efficiency observed after one year of treatment.Due to the high bioavailable content of PAH and the residual sulfate, long-term treatments will require careful monitoring to reduce environmental risks.