Biological sludge, a byproduct of wastewater treatment processes, poses challenges in terms of efficient dewatering and disposal in most countries. Hydrothermal carbonization (T > 180°C) is an effective technology that disrupt the complex biological matrix of the sludge thanks to thermal energy and auto-generated pressure; coupling the hydrothermal treatment with a filter press is an effective method to reduce the volume of the sludge to be disposed of.

In this study we focused on the effect of two key parameters in the hydrothermal carbonization process: time and temperature.. Finding the right balance between residence time, temperature and filtration performance is the key for an efficient process of volumetric reduction of biological sludge. The experiments were conducted over a range of temperatures (160°C – 200°C) and residence times (15min–120min).

The results show that there are lower ...