Hong Kong is currently the only location in the world using seawater for sewage flushing on a city scale. Conventional biological wastewater treatment technology makes use of microbes to clean up sewage by converting organic pollutants into carbon dioxide. The microbial action results in the production of 2,000 tons of sludge every day in Hong Kong. Handling of the sewage sludge not only incurs high costs, but is environmentally unfriendly too since the sludge must then be incinerated in a highly energy intensive and air polluting manner.
.jpg) A research team from HKUST, led by Professor Guanghao Chen of the Department of Civil and Environmental Engineering, has invented a sewage treatment technology known as the "Sulphate Reduction, Autotrophic Denitrification and Nitrification Integrated (SANI)" Process. This novel technology successfully minimizes the adverse environmental impact of sewage treatment plants by eliminating 90% of sewage sludge production, minimizing energy consumption as well as odour and greenhouse-gas emissions. Moreover, it cuts sewage treatment costs and space requirements in half.
.jpg) The SANI Process, using sulphate reduction bacteria integrated with seawater toilet flushing system of Hong Kong, has been recognized by the International Water Association (IWA) as one of the most successful water management systems around the world. This technology has also drawn the attention of the UNESCO-IHE Institute of Water Education which finds it an effective and sustainable approach. After extensive studies and piloting, SANI launched a full-scale trial at Shatin Sewage Treatment Works in summer 2014. With the success of the SANI process combined with seawater supply and wastewater reuse, the HKUST team has formed a partnership with UNESCO-IHE Institute of Water Education to expand a pilot system in Cuba called the "More Water for All" project. Cuba is now facing a serious water scarcity and high water prices, and this project seeks to help Cuba reduce freshwater usage and help mitigate climate change effects.
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