Sha Tin Sewage Treatment Works (HK) - QRA

The Sha Tin Sewage Treatment Works is being considered for a relocation underground in order to free up valuable surface space in the area.

As part of a bigger effort to ensure the long-term sustainability of economic development in Hong Kong, the Sha Tin Sewage Treatment Works is being moved into caverns. This will free up 28 hectares of valuable surface area.

Amberg Engineering, jointly with Enprodes Management Consultancy BV, performed a quantitative risk analysis (QRA) for the proposed design. All possible threats and relevant emergency scenarios were evaluated in a systematic manner. The safety level was compared with relevant risk guidelines and the international state-of-the-art through similar projects worldwide. 
 
The analysis had to account for a wide spectrum of possible threats and incident scenarios related to present hazards and the complexity of the cavern. On the side there are the fire hazards posed by both installed equipment as well as vehicles operated within the facility. But there are also process-specific, chemical hazards stemming from used chemicals and their combinations in case of simultaneous release. Dangers include the release of toxic gases (such as SO2) or combustible air mixtures (for CH4) which all need be considered to some extent. This combines with the complex cavern geometry to multiply the possible scenarios depending on the point of origin for a given emergency.

Thanks to their broad, interdisciplinary expertise in fire and safety, Amberg and Enprodes were able to provide the comprehensive risk assessment required to allow for the development of the optimal design. This includes cost effective measures to ensure safety under all relevant circumstances.