Discharge pipes tell a story of a city’s efforts to manage its waste. Today, we’re standing before the North West Kowloon Preliminary Treatment Works. It is a crucial part of Hong Kong’s Harbour Area Treatment Scheme or HATS.
The North West Kowloon Preliminary Treatment Works is located on Stonecutters Island. This location is strategic. It keeps the deep sewage tunnels to a minimum. These tunnels connect to other Preliminary Treatment Works around Victoria Harbour. The North West Kowloon Preliminary Treatment Works serves Sham Shui Po Yau Ma Tei and Cheung Sha Wan.
HATS addresses Victoria Harbour’s water pollution. Up to the 1980s untreated sewage was discharged into the harbour. This overwhelmed its self-cleansing capacities. The government launched the Sewage Strategy Study in 1987. This study led to the Harbour Area Treatment Scheme.
HATS includes several stages. Stage 1 involved constructing the Stonecutters Island Sewage Treatment Works SCISTW. It also included 23.6 kilometers of deep tunnels. These tunnels collect sewage from various areas. Seven existing preliminary treatment works were upgraded as well. Stage 1 began in 1994. It became operational in December 2001. This stage treated 75% of the harbour’s sewage.
Stage 2A treats the remaining 25% of sewage. This stage included 21 kilometers of deep sewage tunnels. The Stonecutters Island Sewage Treatment Works was expanded. Eight existing preliminary treatment works were upgraded. Major works began in 2009. Stage 2A was commissioned in December 2015.
Together Stages 1 and 2A treat 2.45 million cubic meters of sewage per day. This serves up to 5.7 million people. All sewage is treated and disinfected at the Stonecutters Island Sewage Treatment Works. It is then discharged through an outfall.
The Stonecutters Island Sewage Treatment Works is compact and efficient. It covers only 10.6 hectares. That’s about half the size of Victoria Park. The Stonecutters Island Sewage Treatment Works uses chemically enhanced primary treatment. This process treats sewage collected from the deep tunnel system. The plant is designed to handle 1.7 million cubic meters of sewage per day on average.
The Stonecutters Island Sewage Treatment Works includes several facilities. Main Pumping Station No 1 is one of them. It lifts sewage from the deep tunnels. It then sends it to downstream treatment facilities. The Main Pumping Station No 1 is circular. It has a diameter of 50 meters. It is over 38 meters deep. It contains eight centrifugal pumps.
The Environmental Protection Department confirmed water quality improvements after Stage 2A. There was a tenfold reduction in E. coli count. This was compared to the late 1990s.
The North West Kowloon Preliminary Treatment Works and the Harbour Area Treatment Scheme highlight Hong Kong’s dedication to a cleaner Victoria Harbour. These efforts have revived the harbour’s beauty and vitality. Polluted beaches have reopened. Marine life has returned. The Cross Harbour Race has resumed its course. It is a testament to the improved water quality.
The story of the North West Kowloon Preliminary Treatment Works reminds us that protecting our environment requires ongoing effort and innovative solutions. As we leave this site consider the importance of these facilities in maintaining a healthy and vibrant harbor for future generations.