Shatin relocation to caverns project in Hong Kong is probably one of the most impressive on going sewage treatment works project. Shatin STW (340.000 m3/d) will be in coming years relocated in caverns across the river releasing 28ha of land for other beneficial uses. Main caverns complex at Nui Po Shan of about 14 hectares in area and about 2.3 million cubic metres in total volume will accommodate the sewage treatment facilities. Implementation in caverns, especially in Hong Kong where sea water flushing is used implies many challenges to handle for sludge dewatering. The saline highly changing effluent and cavern related odour management represents a major challenge for that project’s. Presentation will show how and why Bucher Piston press have been identified as the best available solution, ensuring not only the challenging 30% dryness required but also an cost effective solution to cavern space and environment contraints.