Tai Po Water Treatment Works, Hong Kong
Tai Po Water Treatment Works, in Hong Kong, was opened in 2003. The Water Supplies Department (WSD) of Hong Kong officially announced the award of contracts for the expansion of the plant in February 2013. The expansion works are expected to be completed by 2017.
The expansion contract, worth $419m (HK$3.25bn), has been awarded to the China State-Atal joint venture. The expansion will double the treatment capacity of the plant, from the current 400,000m³ per day to 800,000m³ per day when complete.
The current project will primarily include upgrading existing facilities and constructing additional water treatment components at the plant site. The project is expected to generate about 1,330 jobs. The expansion will alleviate the load from the Sha Tin Water Works located nearby.
History of Hong Kong's water treatment project
The design works for the existing Tai Po Water Treatment Works commenced in 1995, with Black & Veatch acting as the consultant. Construction began in 1998 and the plant became operational in 2003 with an initial treatment capacity of 250,000m³ per day.
The plant covers an area of about 10ha. It was constructed with an investment of $4.6bn and currently serves about seven million people within Shenzhen and Hong Kong.
The plant site initially comprised of facilities, such as an administration block, an inlet chamber, a treated water pump station, a dissolved air floatation plant, a secondary rapid gravity filters, a chlorine store, three chemical buildings, two primary aerated biological filters, a sludge press house, supernatant tanks and washwater recovery tanks.
The project won the Global Grand Prize in the Design Project category of the International Water Association (IWA) Project Innovation Awards in 2006.
Water supplies and treatment technology
The plant applies advanced water treatment technology, such as biofiltration, ozonation and dissolved air flotation techniques, to treat the raw water, which is then pumped via a 12km-long tunnel to a primary service reservoir at Butterfly Valley before being supplied to the municipalities of Kowloon and the central and western districts on Hong Kong Island.
The plant treats water using a dissolved air floatation method, aerated biological filtration and rapid gravity filtration.
The first stage of treatment involves a mixture of air and water to lift coagulated solids to the water surface for removal. The second step involves biological treatment where ammonia and manganese are removed. The final stage involves disinfection using chlorine. Ozone and granulated activated carbon filters are also used when deemed necessary.
Tai Po Water Treatment Works expansion
WSD made an announcement in June 2009 to further expand the Tai Po Water Treatment Plant. The consultancy contract to design and supervise the construction works was again awarded to Black & Veatch.
The project involved upgradation of the existing facilities and construction of additional water treatment facilities at the plant site. It also increased the pumping capacities of the raw water and fresh water pumping stations.
The project also increased the storage capacity of the existing Butterfly Valley Fresh Water Primary Service Reservoir in Kwai Tsing and installed new fresh water mains in Sham Shui Po and Kowloon City. The project brought about the creation of roughly 2,100 jobs.
The expansion increased the treatment capacity of the plant from 250,000m³ per day to 400,000m³ per day.
The ongoing expansion will increase the capacities of the raw water pumping station No.4 and the fresh water pumping station. It will further expand the storage capacity of the primary service reservoir at Butterfly Valley, from 40,000m³ to 120,000m³.
The expansion will also witness the placing of about 900m ancillary fresh water mains with diameters ranging from 900mm to 1,800mm in Sham Shui Po and Kowloon City.
The latest programme of improvement at the Shatin Sewage Treatment Works - the largest wastewater plant in Hong Kong - saw its capacity extended and the disinfection regime enhanced and upgraded.
A two-year programme of work began in 2006 to improve Beijing's Bei Xiao He wastewater treatment plant ahead of the 2008 Olympics.