Ecological restoration of a former gravel pit contaminated by a massive petroleum sulfonate spill. A case study: Arganda del Rey. Madrid (Spain)

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• 作者：Pedro Mora Peris^a ; Jorge Castilla Gó ; mez^a ; ^{jorge.castilla@upm.es} ; Juan Herrera Herbert^a ; Daniel Barettino Fraile^b
• 关键词：Petroleum sulfonate ; Ecological restoration ; Contaminated soils ; Chemical characterization ; Waste recovery ; Waste valorization ; Ecosystem rehabilitation
• 刊名：Ecological Engineering
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：100
• 期：Complete
• 页码：73-88
• 全文大小：3357 K
• 卷排序：100

文摘

In this article, possible alternative courses of action to effect the environmental recovery of a former gravel pit are assessed. The pit was severely contaminated by petroleum sulfonate, for a decade, towards the end of the 1980s. The dumping was carried out by a company involved in the recovery of used oils, at a time when environmental regulation was extremely permissive. Faced with the problem the current restoration of this contaminated pond presents, different solutions and methods of dealing with the contaminating materials, with the soils, and with the environment were studied in order to thus obtain a complete and effective decontamination of the site and to achieve a complete recovery of the biodiversity. The final solution arrived at should be the very best possible solution to fulfill all the objectives described, and should be tailored, when being applied, to a specific sequence of works adapted to the precise characteristics of the contaminants present.Affected area restoration presented a great challenge, both a technical and an environmental challenge. This is because the contaminating elements are formed of a mix of different compositions and with diverse physico-chemical properties. These factors made the choice of just one single method of treatment and of restoration impossible.Within the different technical options available, the choice manner to restore the affected zone combines methods and techniques based on initial material recovery in order to make a later energetic valorization, in an external plant and to use thermal desorption treatments to restore the contaminated land.In the ecological restoration of the pond, three different categories of actions have been identified. First is the recovery of the contaminating material of the pond; second is the recovery of the soil contaminated by the sulfonate and third category is the final restoration technique to provide the best solution for the ecological objectives.For the recovery of the contaminating material of the pond, several options have been assessed, including reuse, recovery, valorisation and disposal techniques. The best solution for the ecological restoration is ex situ waste energy recovery. This is considered the very best alternative for the treatment of petroleum because it leads to the elimination of the main focus of contamination; it brings energy value to the contaminating material; it represents a simple alternative which minimizes site equipment installation and it guarantees to be operational and acceptable costs.Regarding the soil reclamation, different thermal, energetic and mechanical options have been assessed. The selected option consist on thermal treatment via thermal desorption. This might be considered a perfect solution to the problem of polluted soils, given that the main issue is organic compound contamination (TPHs, PAHs, PCBs, etc.), based on the analytic tests carried out at soil.To complete the ecological restoration a flora and fauna management technique has to be selected. A partial refilling of the site and the creation of ecological niches of interest has been considered as an optimal solution for biodiversity rehabilitation.