Our environmental interventions in Manfredonia

We are about to complete a complex remediation project, which stands out for innovative and sustainable groundwater management.

Manfredonia

Manfredonia, innovation and commitment towards recovery

In the Manfredonia and Monte Sant’Angelo Site of National Priority, which covers 216 hectares and is partly included in the Southern Adriatic Special Economic Zone (SEZ), we own the former Anic plant areas, covering approximately 96 hectares across 17 islands. Of these, 94.6 hectares are available for reuse, having already undergone remediation or not affected by contamination. The petrochemical hub was established in 1968 to produce fertilisers, and in the 1970s saw the development of industrial activities related to caprolactam, ammonium sulfate, and other derivatives. Since 1976, following an explosion at the ammonia-urea plant, production activities were gradually phased out until final closure between 1988 and 1994. In the late 1990s, at the same time with the designation as a Site of National Priority, Enichem began environmental activities. At present, as Eni Rewind, we ensure groundwater remediation in an innovative and sustainable manner, respecting the hydrogeological balance that characterises the area. Furthermore, we have completed almost all the interventions on the soil matrix, most of which are in the certification phase, with the perspective of the development of new projects. Minor interventions on the deep soils of Island 16, covering a total of approximately 1.4 hectares, remain underway due to the presence of residual contamination that cannot be removed through excavations and disposal. As of 31 December 2024, we have incurred environmental costs for our areas amounting to €365 million.

Manfredonia: key elements

A site in transition: from a historic petrochemical hub to a laboratory for innovation, technology, and sustainable development of the territory.
Area valorisation
Area valorisation

To date, 94.6 of the 96 hectares owned in Manfredonia are already available for new development initiatives.

Water conservancy
Water conservancy

The solution adopted for aquifer remediation integrates the need to manage saline intrusion with the maintenance of hydrogeological balance through the reintroduction of water into the aquifer.

Remediation and innovation
Remediation and innovation

The application of in situ Ground Circulation Wells technology also allows for the removal of immobilised contaminants that cannot be extracted with traditional techniques such as pump & treat.

Manfredonia at a glance

Icona tagLocation: Italy, Puglia
Icona tagStart of the environmental interventions: 1999

Manfredonia past and present

Site history

Start of the remediation process

In 1998 the Site of National Priority was identified and the following year Enichem began the remediation process.

Progressive closure of the activities

Since 1976, following an explosion in the ammonia-urea plant, production was gradually ceased until the caprolactam and fertiliser plants closed between 1988 and 1994.

Anic becomes the sole owner of Chimica Dauna

Anic acquired 50% of the shares owned by Snia Viscosa. Chimica Dauna is then merged into Anic Agricoltura (later Enichem Agricoltura).

Expansion of productive activities

The company Chimica Dauna, owned 50% by Anic and 50% by Snia Viscosa, established the plants for the production of caprolactam, ammonium sulfate, and other derivatives.

With Anic the petrochemical site is established

The Manfredonia and Monte Sant’Angelo petrochemical plant was founded in 1968 by Anic for the production of fertilisers.

Our activities in Manfredonia

The site's environmental clean-up began in 1999 with an investigation plan aimed at the qualitative definition of the soil, with the exclusion of the plant areas. Between 2003 and 2016, we decommissioned the plants, removed waste in areas formerly used as landfills (islands 12, 14, 16, and 17) and in contamination nuclei (islands 13, 20, and perimeter areas). We also completed soil reclamation of the former Enel site. The additional characterisation campaign carried out in the areas where the plants had stood, following their demolition, highlighted residual contamination involving a total of 2.6 hectares distributed over the islands 5, 9, 14, 15, 16 and 17. For the remediation of these hot spots, we submitted the respective remediation projects in 2016, all of which were approved with the exception of island 15, which was declared non-contaminated in terms of a Ministerial Decree in 2021. At the present time, the interventions for Islands 17 and 9 have obtained certification, those for Islands 5,14, 20 and the perimeter areas are pending certification, while those planned for island 16 are still underway. To the present day, 94.6 of the 96 hectares owned in Manfredonia are already available for new initiatives. As far as the groundwater is concerned, the site has been operating a system of hydraulic pumping and barriers since 2006, further enhanced following the approval of the project variant in 2019. The water is extracted from contaminated areas within the site and once treated by the groundwater treatment plant (GTP), enhanced in 2021, reintroduced into the groundwater along the plant’s perimeter. This reinjection solution prevents the depletion of the aquifer and reduces waste production. On Island 5, we are implementing Ground Circulation Well technology to accelerate the remediation of the underlying aquifer.

Status of the environmental process

The administrative procedure for environmental interventions in the areas owned by Eni Rewind has concluded with the issuance of ministerial decrees for all the remediation projects submitted.

Sustainable management for groundwater remediation

The solution adopted in Manfredonia for groundwater remediation is tied to the necessity of managing both saline intrusion and the karst nature of the subsoil that characterises the area. At the same time, it is necessary to compensate aquifer extractions with the reintroduction of freshwater, so as not to alter the area’s hydrogeological balance. This is achieved through an injection barrier along the site perimeter, which for the first fifteen years was supplied by both treated groundwater and freshwater from the Capitanata pipeline. With the groundwater project variant, approved in 2019, we designed a revision of the water extraction and reinjection systems in order to optimise the remediation process and eliminate water withdrawal, in the perspective of sustainable environmental management. Through the interventions, which included additional wells and piezometers, in addition to the enhancement of the groundwater treatment plant from 120 to 240 m³/h, at the present day the reinjection into the aquifer is carried out exclusively with the water treated on site.

Circulation wells

Since 2021, in collaboration with the Sapienza University of Rome, at Island 5 we implement the Groundwater Circulation Wells technology: a closed circuit in which the extraction, treatment and reintroduction of water into the subsoil take place at a concentration lower than that of extraction and at a different depth in the same well. Extraction and reintroduction create a circulation cell around the well that acts both vertically and horizontally, promoting contaminants mobilisation even in the fine fractions. This in-situ technology removes immobilised contaminants that cannot be extracted with traditional techniques such as pump-and-treat. The trend observed, with the concentrations in the groundwater progressively decreasing, demonstrates the technology's effectiveness.

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