Latest News - ECOTI Project

After successful commissioning of their first landfill treatment plant in Tunisia, collecting landfill leachate from Sousse, Monastir and Kairouan, Wehrle has won a follow-up order for the landfill leachate treatment plant in Nabeul. The Tunisian-Italian company ECOTI, by order of the Agence Nationale de Gestion des Déchets (ANGed), operates both landfill sites and is responsible for leachate treatment.

The landfill leachate from new landfill sites in Tunisia is characterised by very high organic loading and above-average salt concentration. This leachate composition places high demands on the engineered process, in particular the design and construction of the air supply in the biological system, as well as the implementation of control systems.

The concept installed at Sousse proved to be very effective and has also been applied to the project in Nabeul. In the pre-treatment stage screeining and Dissolved Air Flotation will be used to treat the high solids loading in the leachate . This way a large part of settleable and floatable solids can be effectively removed.

Organic components will then be removed in the Membrane-BioReactor comprising an activated sludge treatment step. Wehrle focuses on providing a highly effective air suply to the biological system by using an ejector system. This way the bacteria can be reliably supplied with enough oxygen to guarantee as much degradation of organic materials as possible. The last step is to retain the non-degradable contents (e.g. residual COD and salts) in the ultrafiltration membrane unit. The project will also inlcude sludge dewatering and a system for cooling the biologcal system.

The plant in Tunisia has been constructed to the high standard expected by WEHRLE, thanks to many years‘ experience in the treatment of particularly concentrated leachate.

This concept is also a major benefit for the Tunisian market, guaranteeing reliable leachate treatment and producing a source of clean water for use in irrigation and agriculture.

Author: Anna Natau

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