Cleanup techniques

For each site, the choice of reclamation techniques takes into account the type of contamination, therefore the characteristics of specific contaminants as well as the assessment of environmental benefits and future reuse of areas. Eni Rewind characterises, contains, reclaims and monitors contaminated sites (lands and aquifers) with the application of state-of-the-art methodologies which are developed in collaboration with Eni research centres and top universities in Italy and abroad.

Types of reclamation processes

Reclamation processes can generally be classified according to the place in which they are applied:

Thanks to our research, which focuses on low environmental impact techniques, in situ ones in particular, we have developed decision-making and monitoring tools at the service of the site cleanup process, with the registration of brands and patents.

Passive soil and sediment sampling is our very own technique used to measure the actual impact of contaminants in sediment and soil. Speciation of metals and metalloids is used for the identification of chemical forms of mercury, to understand interactions between contaminant and matrix. The sampler developed by our own research is used for the estimation of soil-gas light hydrocarbon concentrations, including BTEX and volatile organic-chlorinated compounds. The sampler contains a low density Polyethylene film (LDPE) and is set in the soil for the length of time required for it to reach a balanced state. The polyethylene film is recovered and sent to the laboratory to analyse absorbed concentrations. The raw data is rendered in table form and associated with the site-specific polyethylene-air coefficient (Kpea) obtained in the laboratory, so as to reconstruct concentration in soil gas. The technique has been developed to overcome many of the uncertainties present in traditional techniques (nesty probe, flux chamber), to obtain data which can be directly used in AdR calculations.
Development of Sustainable Assessment Framework software (SAF) to assess different intervention methods based on three fundamental requirements of sustainability: social, economic and environmental;
Patent for the e-hyrec® device, for the selective recovery of organic aquifer matter. The device is capable of selectively pumping the supernatant present in the aquifer, when inserted inside a piezometric well. The system is fitted with a sintered steel filter onto which a layer of polydimethylsiloxane (PDMS) is deposited, making the surface hydrophobic. During operation, organic matter selectively permeates through a filter in contact with the liquid, whereas water is repelled from the surface, thanks to the characteristics of filtering material. The system enables continuous contaminant removal, pumping permeated matter to the surface while leaving water in the aquifer. Thanks to the e-hyrec® device, aquifer reclamation is made possible without the extraction of water, reducing water disposal costs and energy consumption compared to traditional pumping systems.
Use and experimentation of phytoremediation and registration of the e-IBS-ABR® brand for the integrated bioremediation system.
Application of Enhanced Natural Attenuation (ENA) and bioaugmentation.
Experimentation of passive treatment, for example: direct osmosis and Raps units for acid mining waters. Direct osmosis is an emerging technique under development and is based on the use of a semi-permeable membrane fitted between the aliment and a strong synthetic saline water (draw solution, DS). A spontaneous flow is established (i.e. without the application of any hydraulic pressure, at atmospheric pressure) of fresh water from the aliment (which is concentrated) to the DS (which is diluted). Once fresh water is recovered, DS restored to initial concentration levels can be recycled for reuse in the process. RAPS units: passive treatment process of acid mining water. Currently laboratory and pilot scale experimentation is under way of main treatment units, including a drainer-reducer, RAPS, which consists of a series of organic compost and calcium beds, along with an oxidation-sedimentation unit.
Patented technology (Bluewater) which enables the chemical/physical/biological treatment of water used in production.
Development and application of dynamic SAF used by MIAMI (integrated microbiological and isotopic analysis methods) and fingerprinting.

MIAMI (integrated microbiological and isotopic analysis methods)
Isotopic methodology enables more accurate contaminant characterisation, reducing the degree of uncertainty typical of traditional methods, while also identifying the actual source of contamination. Combining this methodology with the molecular technique enables the assessment and quantification of the degree and process of alteration the contaminant is subjected to in the environment.

Molecular fingerprinting The qPCR, quantitative PCR or gene amplification technique is used, based on the quantitative Polymerase Chain Reaction. It consists of searching for gene markers association with in situ biodegradation of main contaminants. Specifically, markers of aerobic/anaerobic degradation are searched for in bacterial DNA extracted from groundwater. The presence of gene markers associated with specific reactions of bacterial biodegradation in groundwater samples indicates potential applicability of bioremediation.

Isotopic fingerprinting The technique involves analysing the isotopic ratio of rare and abundant isotopes of a specific chemical element, by means of GC-IRMS (Gas Chromatography Isotope Ratio Mass Spectrometry). Stable isotopes do not decay, however their ratio changes during the biodegradation process, due to microorganisms. Many biochemical processes tend to result in products rich in lighter isotopes, with a consequent progressive enrichment in heavier ones in the substrate. This phenomenon is called "fractioning" and enables the assessment of attenuation processes of the pollutant plume with a quantitative approach.

Eni Rewind S.p.A. - Company subject to direction and coordination by Eni S.p.A.

Registered office
Piazza Boldrini, 1
20097 San Donato Milanese (MI)

Company Share Capital
€ 355.145.040,30 fully paid up

Tax identification and Milan-Monza-Brianza-Lodi Business Registry
no. 09702540155