Middlesborough - Bran Sands

The Bran Sands Advanced Anaerobic Digestion Facility is operated by Northumbrian Water (NWL).In the early 2000s, the ban on sludge disposal in the North Sea prompted NWL to build the largest thermal drying facility in the UK, making them consider new technologies for sludge treatment.  

The facility treats indigenous and imported sludge cake at 25% dry solids. Indigenous sludge is dewatered using gravity tables and dewatering belts, and the cake is stored in storage tanks. Upon dilution, the cake is fed into the thermal hydrolysis process unit at 16-17% DS. Anaerobic digestion occurs in three concrete digesters with a working volume of 6700 m3 and operates at 5.5 kg VS/m3. The digested cake is dewatered at 35% dry solids and stored for about seven days for further dewatering capabilities. The biogas generated is used for combined heat and power (CHP) production and by on-site boilers.  

The advanced sludge management strategy by NWL makes the facility energy self-sufficient. In 2020, NWL made site investments to export power to the grid.