Proceedings

In 2003, Lyonnaise des Eaux decided to launch a facility at the Limay Porcheville site dedicated to drying sludge from a broad
range of sources. The purpose of this paper is to outline Degrémont's design for this centralised sludge-drying unit and
preliminary feedback from the project. The Limay site is a licensed site and is not located at a wastewater treatment plant and
is consequently subject to a prefectoral order limiting flow capacity and concentration for various discharge matter. This unit
receives sludge from large and small wastewater plants throughout the greater Paris region. Dry solids content ranges from
16 to 35%, and sludge texture varies highly depending on its origin and the associated dewatering method.
The scope of the proposed paper will deal with the following items:

• The technical design specifications of the unit (dryers and ancillary equipment)
• Details of the thermal loop with the mineral oil used as heat-transfer fluid
• Handling and shaping of dried product depending on the end use of the product
• Treatment of vapours from the dryers associated with odour and effluent treatment
• Problems encountered and lessons learned

KEY WORDS
Centralised facility, drying, sludge, Limay, Naratherm, pelletising,