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Geosynthetic capping sealing system rehabilitates the Croatian Osojnica landfill

Case Studies, News | December 16, 2021 | By:

The landfill will become a green hill that blends perfectly into the landscape of the idyllic coastal region.

Installation of the geosynthetic capping sealing system inside the gabion wall. Photograph courtesy of Naue GmbH & Co. KG

The Croatian municipality of Matulji is an idyllic seaside resort on Kvarner Bay in northwestern Croatia, 8 miles (13 km) northwest of Rijeka. The Osojnica landfill is another 3 miles (5 km) northwest of Matulji in a forested area at the foot of Učka Mountain. Since 1967, municipal waste from the coastal region of Liburnia has been deposited at this location. The estimated amount of waste is 16.8 million cubic feet (475,000 m3) and covers an area of 340,000 square feet (31,800 m2).

In October 2019, Naue GmbH & Co. KG’s Croatian partner G. T. Trade received the order for the rehabilitation of the landfill. The work began in April 2020 and included the relocation of 5.3 million cubic feet (150,000 m³) of waste near the boundary of the landfill to build a gabion wall. This new structure, with a height of up to 72 feet (22 m) over a length of 794 feet (242 m), encloses the rehabilitated landfill. The retaining wall, reinforced in layers with high-strength uniaxial Naue Secugrid 150/40 R6 polyester (PET) geogrids, increases the stability of the landfill body and creates additional landfill volume via its steep 80˚ inclined facing system, which was necessary due to the mass relocation.

The geosynthetic capping sealing system reduces pollutant emissions

An essential part of the rehabilitation works was to seal and recultivate the surface of the landfill to prevent infiltration of rainwater and counteract the formation of polluted seepage water. The capping sealing system consisted of a Bentofix geosynthetic clay liner, a Secudrain drainage mat for safe drainage of rainwater and a Secumat erosion control mat with cover soil. The geosynthetic capping sealing system makes a significant contribution to reducing future pollutant emissions. To prevent sliding of the cover soil on top of the geosynthetic drainage mat, a Secugrid 80/20 R6 geogrid was used as veneer reinforcement.

The costs for the rehabilitation and closure of the landfill total $5.9 million (5.2 million Euros). The city of Matulji received grants of $4.5 million (4 million Euros) and $564,000 (0.5 million Euros) from the Fund for Environmental Protection and Energy Efficiency of the Croatian Ministarstvo Zaštite Okoliša i Energetike (Ministry of Environment and Energy).

The rehabilitation work on the Osojnica landfill was successfully completed in Oct. 2021. Odors caused by the landfill in the Matulji community will be a thing of the past.

This article first appeared on the Naue blog,

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