Sewage sludge moisture meter

Valorising waste is a necessity in the face of diminishing resources. This valorisation, environmental or energetical, has two main advantages :
- Reducting the volume of waste, and thus pollution, which would result without any recycling.
- Preservating natural resources, since the recycled material substitutes for material that would have had to have been extracted

Recycling sewage sludge

Increased costs of disposal and transport shows environmental and economic opportunities to reduce the mass of sewage sludge to a minimum.

At the end of wastewater treatment, sewage sludge water content is about 99% of the raw matter. Reducing the mass to handle in avoiding dust and improving quality are the primary issues of the valorization and the recycling of sewage sludge. Treatment can occur by reducing its water content, notably through drying.

Sewage sludge drying

By evaporation, sewage sludge loses all or part of its water and becomes solid.

Sludge drying beds

The technique of drying beds is done outdoors on liquid sludge and combines natural evaporation and free water drainage through a filter layer of sand and gravel. This extensive system, depending on weather conditions, gets the solid sludge to 35-40% of dry content.

Thermal drying

Thermal drying allows virtual elimination of water (dry content around 95%). The resulting sludge is either powder or granules/pellets. Thermal drying should develop in the coming years because other systems for sludge treatment, including incineration, are more expensive as a result of new regulatory and economic conditions.