Broomfield, Colo. For the over seven million people living in the Special Administrative Region (SAR) of Hong Kong, what goes on below ground is nearly as significant as what goes on at the surface, particularly when it comes to sewage. Located on Victoria Harbour, in an area roughly one-third the size of Rhode Island, the Hong Kong SAR has little room for utility infrastructure. Thus, for over 50 years, much of the industrial and domestic sewage has been treated by screening plants and then discharged into Victoria Harbour, causing significant water pollution, and increased environmental and social concerns.
Now, after nearly a decade of political and social negotiation, the SAR's first deep tunnel sewerage network, designed and managed by MWH, is complete. A key part of Hong Kong's US$3.5 billion multi-stage Harbour Area Treatment Scheme (HATS) project, the seven deep tunnels collect sewage from the urban areas of Kowloon and the northeastern region of Hong Kong Island and transfer it to Stonecutters Island for treatment and disposal. Through a complex series of drop shafts and tunnels, the MWH team designed this 23.3-kilometer, deep-tunnel conveyance system to allow the shortest route and to minimize disturbance and nuisance to the environment, traffic, existing utilities, transport systems and buildings, during construction.
All the tunnels are at least 90 meters and as much as 150 meters below ground, making these the deepest tunnels ever built in Hong Kong. The tunnels vary in diameter from 1,200 millimeters at the upstream end of the system to five meters at the Stage I Outfall downstream of the sewage treatment works.
With the successful commissioning of Stage I by December 2001, it is estimated that 70 percent of the sewage flow entering Victoria Harbour will be intercepted and receive a much higher level treatment before disposal through the new outfall.
The MWH HATS Stage I project team involved many people over an eight-year span, including Mike Oswell, Project Director; Doug McLearie, Project Manager; and others.
MWH is a leader in global infrastructure development. The company is the result of a recent and historic merger between Montgomery Watson and Harza Engineering Company. With more than $721 million in revenue, MWH more than 6000 specialists in 30-plus nations and a legacy of more than 231 years of combined experience.
Montgomery Watson and Harza Engineering Company have engineered, constructed, financed and managed many of the largest and most technologically significant infrastructure projects in the world. These programs have ranged from designing one of the world's largest hydroelectric plants in South America to helping one of Europe's largest utilities expand its water and wastewater infrastructure. More information about the company is available at www.mw.com.
