ECSM’08 - European Conference on Sludge Management: Dewatering, Drying and Thermal Valorization

This conference aims to bring together researchers and engineers from universities, R&D laboratories, water agencies and private companies involved in the management of sewage sludge as well as governmental delegates.

According to stringent environmental regulations, the production of sludge from wastewater treatment plants has been continuously increasing worldwide for several years. The treatment of each so-called Equivalent Inhabitant leads to an annual production of about 30 to 40 kg of sludge, expressed on a dry basis. Taking into account the remaining water at the outlet of mechanical dewatering processes, the total mass is roughly 4 to 5 times higher. Within the European Union, sludge production reached 9.4 million tonnes of dry matter in 2005.

The management of these growing amounts of sludge has become a key issue. Considering the recent ban on dumping non ultimate wastes, energy valorization and landspreading remain the two major issues for sewage sludge. Besides research for new or improved valorization ways, some effort remains to be done to improve mechanical dewatering and drying processes.

Water removal is of high importance for many reasons among them:
- mass and volume reduction and, consequently, cost reduction for storage, handling and transport
- transformation into an acceptable combustible whose calorific value depends on the siccity level
- stabilization and hygienization of the product when high temperature are used during drying
- ...

From an economical point of view, as much water as possible has to be removed mechanically, explaining why improvement of dewatering processes is still needed.

Concerning thermal dewatering, the drying behaviour of sludges remains difficult to predict and may strongly vary from one plant to another. This makes difficult the choice of the appropriate drying technology among the numerous ones available on the market. Moreover, as drying is a high energy consuming unit operation, it is required to optimize the process in order to make a rational use of energy and to reduce GHG emission.

Regarding valorization issues, this conference wants to focus on thermal processes that are currently studied as alternative methods of treatment.