The water content refers to the amount of water in a substance, expressed as a percentage of the total weight. In the case of sludge, the water content measures the proportion of water compared to the dry matteri.e. the solids. This value is a critical factor in the sludge drying process.

Importance of the water content for sludge drying

In the sludge drying the water content plays a central role, as it directly influences energy efficiency and costs. Sludge with a high water content, for example, requires more energy during dewatering. dewatering.

An optimally controlled water content, on the other hand, not only improves the efficiency of the drying process, but also the quality of the dried product by preventing the formation of lumps and ensuring more uniform drying. 

The water content also has an impact on the transportability of the sludge, as water-rich sludges are difficult to transport due to their consistency, high weight and volume. For this logistical reason too, one of the main tasks of sludge drying is to reduce the water content of the sludge.

Last but not least, an optimal water content minimizes CO₂ emissions and the general environmental compatibility of the processed sludge. Precise control of the water content helps to meet regulatory requirements regarding the final disposal or further use of the dried sludge.

Water content in sludge drying - a before and after comparison

Before drying, the water content in sludge is between 70% and 99%depending on the previous treatment and the type of sludge. After effective sludge drying, the ideal water content is between 10% and 30%.
This enables safe storage, efficient transportation and possible further use as a fuel or soil conditioner. The reduction of the water content to less than a quarter of the total weight also reduces the risk of microbial growth and odor formation.