At the International Water Association’s World Water Congress & Exhibition 2022 recently held in Copenhagen, Denmark, the project of Sustainability and Resource Recovery from Organic Waste: the First Sludge & Food Waste Co-digestion Project in China from Tongji University won silver in IWA Project Innovation Awards (PIA). The project was headed by Professor DAI Xiaohu's team from the College of Environmental Science and Engineering of Tongji University and completed in collaboration with Tongji University, Shanghai Municipal Engineering Design and Research Institute, Zhenjiang Water Industry Co., Ltd, Shanghai Tongji Prand Biomass Energy Co., Ltd. and Technical University of Braunschweig in Germany. This 13th edition of the PIA program featured six categories with three finalists each. There were 18 winners of the six categories, among which two silvers went to projects from China.
Figure 1: The gala ceremony of the IWA World Water Congress 2022 (Copenhagen, Denmark)
Figure 2: Members of Professor DAI Xiaohu's research team and of Shanghai Municipal Engineering Design and Research Institute
The project team explored the low organic load and poor operating efficiency of traditional anaerobic digestion of low organic matter sludge in China with support from the Major National Water Pollution Control and Treatment Scheme. They focused their research on the co-digestion system of sludge and kitchen organic wastes and explained the ammonia/salt/organic acid inhibition and mitigation mechanism of them. Key regulation parameters of enhanced collaborative digestion of sludge and organic wastes were identified, and the coordinated anaerobic digestion regulation technology of sludge and organic wastes based on the multi-media compatibility model was developed. Without increasing the capacity of the container, the sludge digestion facilities could simultaneously consume the same amount of kitchen waste, thus overcoming the shortcomings of low anaerobic digestion gas production rate of sludge and easy acidification of kitchen waste, and significantly improving the comprehensive efficiency of anaerobic digestion. The technology has been successfully applied in the industry use in Zhenjiang, Jiangsu Province. The bio-natural gas produced was purified and then sent to the natural gas pipeline. The biogas residue was used as the urban green soil conditioner and the green nutrient soil for gardens. The biogas slurry was pretreated and discharged into the municipal sewage plant for treatment. A "Zhenjiang Mode" of sludge and urban organic matter collaborating on anaerobic digestion and land use has been formed and has been promoted and applied in Zhenjiang Phase II project, and other projects in Jiujiang, Lu'an, and other places. It plays a good exemplary and leading role and has shown significant social, economic, and environmental benefits. In addition, the collaborative treatment of kitchen waste and domestic sludge has a negative carbon emission effect, which is of great significance for achieving carbon emission reduction in the sewage treatment industry.
Figure 3: The first domestic anaerobic digestion project of collaborating municipal sludge and kitchen waste in Zhenjiang
The Project Innovation Awards of the IWA aims to recognize outstanding contributions and innovations in water science and technology, management, research, and technology worldwide. The award is awarded biennially to encourage the world's industry to contribute to the sustainable development of water resources.
Professor Kala Vairavamoorthy, Executive Director of IWA, gave his compliments on the technological innovation exploration practice of Tongji University. He noted that the implementation of the project has solved the problem of the way out for the sludge of the sewage treatment plant, improved the living environment conditions of cities and residents, and provided a new way out for the resourceful treatment and safe disposal of organic wastes such as urban kitchen waste. It is of great significance for the resource recycling and low-carbon development of the sewage treatment industry in the world, especially in China.
