Sludge Treatment Facility, Hong Kong
The Hong Kong Government's Environmental Protection Department (EPD) has embarked on a major project to construct the largest sludge treatment plant in the world. The facility is located at Tsang Tsui, Tuen Mun. Construction works for the facility commenced in 2010 and are slated for completion in 2013.
The project is being implemented by the Veolia-Leighton-John Holland joint venture (JV) with a overall investment of $660m. A detailed evaluation of the project was earlier carried out by AECOM. The operation of the plant will be jointly carried out by Veolia Water and Veolia Environmental Services under a 15-year contract.
The facility will have a sludge treatment capacity of 2,000t per day and will also be capable of generating 20MW of electricity.
Purpose of the Sludge Treatment Facility
The Sludge Treatment Facility is being built to tackle the increasing amount of sludge being generated from the city of Hong Kong. The proposal for the project was announced in 2007.
The current estimate of sludge disposal from the city stands at 900t per day, which is expected to increase to 2,000t per day following the completion of another major project in Hong Kong, known as the Harbour Area Treatment Scheme (HATS) Stage 2A by 2016.
The new plant will primarily collect sludge generated from the Stonecutters Island Sewage Treatment Works and ten other wastewater treatment facilities located in Hong Kong. The treatment plant will incinerate the sludge, thus alleviating the city from the continuing sewage sludge disposal problem and reducing the increasing number of landfills in and around the city.
Details of the world's largest sludge treatment plant
The sludge treatment building design incorporates a wave-form structure. The plant will be equipped with flue gas treatment lines. It will also witness the construction and installation of steam-producing incinerator boiler furnaces which will drive the turbines to convert the steam into electricity.
Energy generated from the plant will exceed the needs of the plant and thus the surplus energy generated will be supplied to the national grid. It is expected to generate €20m ($25m) in revenue on an annual basis through sales of the surplus power.
A seawater desalination plant with a capacity of 600m3 per day will also be constructed to meet the potable water needs at the plant site. The facility will also be equipped with a wastewater treatment plant to eliminate discharges into the sea.
An environmental education centre will be built incorporating a visitor's gallery and a viewing platform, lecture theatres, an exhibition space, indoor spas, coffee and gift shops, outdoor gardens with foot baths and water features for public use, and a habitat for water birds.
Technology at Hong Kong's treatment plant
The plant will apply the incineration technology for the treatment of sludge. The treatment process will involve the burning of organic substances found in the sludge and convert them into ash, flue gas and heat. Incineration of sludge will take place in fluidised bed incinerators, where technology involved will evaporate all water content in the sludge and burn 90% of the remaining solid component.
Contractors involved with Hong Kong's Sludge Treatment Facility
The principal design works for the facility are being provided by Arup, under a contract awarded in March 2011. The company also acted as the civil, structural, geotechnical and power generation designer during the tendering stage of the project.
The heat exchanger bundles for the air-cooled condenser were supplied by Hamon and the bundles were shipped by Celtic China Group.
The fabrication, delivery and erection of steel structures to support the silos and turbine are being carried out by Ho Wah Steel Engineering.
Hi Tak Thermal & Acoustic Insulation Engineering has been contracted to carry out the fabrication, supply and installation of insulation, turbine building, waste and process water treatment plant, and interconnecting pipes.
The building design was provided by Vasconi & Associates and developed by P&T Architects & Engineers. The building information modelling services for the project were provided by Bentley.
Harbour Area Treatment Scheme (HATS), earlier known as the Strategic Sewage Disposal Scheme, is a huge project being implemented by the Drainage Services Department of Hong Kong.
Drainage Services Department (DSD) of Hong Kong has started the construction works for the Happy Valley Underground Stormwater Storage Scheme (HVUSSS).