Dean's Message
Spring 2012  No.21
Sewage Treatment Goes Green

Novel technology that successfully minimizes the adverse environmental impact of sewage treatment plants has been invented by a research team led by Prof Guanghao Chen, Civil and Environmental Engineering.

Prof Chen said the Sulphate Reduction, Autotrophic Denitrification and Nitrification Integrated (SANI) Process eliminates 90% of sewage sludge production, minimizing energy consumption as well as odor and greenhouse-gas emissions. It also reduces sewage treatment costs and space requirements by 50%.

The SANI Process, which uses sulphate reduction bacteria integrated with Hong Kong's seawater toilet flushing system, has been recognized by the International Water Association (IWA) as one of the most successful water management systems around the world. In recognition of Prof Chen's remarkable research achievements, he was recently elected a Fellow of the IWA, becoming the first Hong Kong scholar to receive this prestigious honor.

The research project started in 2004, followed by pilot testing at Tung Chung Sewage Pumping Station for two years. The technology has now passed the medium-scale test at the capacity of 10 tonnes of sewage per day.

Partnering Prof Chen's team are Delft University of Technology in the Netherlands and the University of Cape Town in South Africa, in collaboration with Hong Kong Airport Authority, the Water Supplies Department and the Drainage Services Department.

Ir Lee Tak Ma, Director of Water Supplies, said: "The SANI Process perfectly integrates the freshwater system and seawater system. This innovative sewage treatment technology maps out an excellent plan for developing the seawater toilet flushing system, as well as the reuse and recycling of saline sewage."

The technology has also drawn the attention of the UNESCO-IHE Institute of Water Education which has found it an effective and sustainable water resource.