Our harbour has shaped Hong Kong and its people for centuries. Over the past 25 years, the phased implementation of the Harbour Area Treatment Scheme (HATS) has restored the beauty and fragrance of Victoria Harbour, which had been lost to serious pollution by the 1980s. The story of HATS is a stellar example of how the Drainage Services Department (DSD) provides world-class sewerage services to protect public health and enable the sustainable development of Hong Kong.


Renowned worldwide for its engineering feats, HATS has won major international awards and helped put Hong Kong at the forefront of global infrastructure excellence. Indeed, Hong Kong has been ranked first in the world in infrastructure by the World Economic Forum for eight consecutive years, an achievement to be proud of and a legacy for us all to continue.


HATS is also unique for its compactness and efficiency. Comprising a labyrinth of deep sewage tunnels embedded in the bedrock stratum and a centralised sewage treatment works on a 10-hectare site on Stonecutters Island, which is just about half the size of Victoria Park, HATS now serves the sewage treatment needs of around 4.5 million people on both sides of the harbour. With a capacity to serve up to 5.7 million people, HATS is probably the most efficient sewage treatment system of its kind in the world.


Interestingly, despite the importance of sewage treatment in daily life, the community is seldom aware of HATS. This is a testimony to another HATS achievement: by putting its sewage tunnels deep in the bedrock, disruption to the community during construction was kept to a minimum. While it was business as usual for Hong Kong, a pioneering environmental infrastructure was being built deep beneath the city to give a new lease of life to our harbour.


Having worked on both Stages 1 and 2A of the project, I look back at my long association with HATS with a sense of honour and privilege. The numerous technical hurdles, twists and turns, setbacks and eventual successes that the DSD team experienced have not only been dramatic and very challenging, but always inspiring and fascinating. This book is a record of this extraordinary journey. We dedicate the book to our dear Victoria Harbour and the people of Hong Kong, for whom HATS exists to serve.