The researchers at the National University of Singapore (NUS) have developed a anaerobic digester system to recycle food waste to produce electricity, heat and fertilisers.
Led by Associate Professor Tong Yen Wah from the Department of Chemical and Biomolecular Engineering at NUS Faculty of Engineering, researchers from NUS and Shanghai Jiao Tong University have jointly developed a system that is self-sustaining.
The generated electricity and heat fully power the system and its processes, said NUS in a press release.
In Singapore, food waste reportedly accounts for about 10 per cent of the total waste generated in the nation, while the recycling rate of such wastes is currently at about 14 per cent.
“We want to play our part in reducing waste in Singapore,” said Assoc Prof Tong. “Our digester system is easy to operate, and we can now generate electricity, heat and fertilisers from food waste that would otherwise be disposed of.”
Moreover, “all the processes in the system can be easily controlled and monitored to ensure optimal performance and safety. There are sensors programmed to send out end-of-process updates and flag any safety concerns in real-time directly to the team via mobile phone alerts.”
The anaerobic digester converts about 80 percent of the food waste fed into the system into nutrient-rich digestate, which can be processed to produce liquid fertilisers for farming and horticultural needs.
A mobile anaerobic digester system is currently being piloted at Raffles Hall, one of the six halls of residence of NUS. The project has been ongoing for about six months beginning from late January 2018.
“Unlike composting which is used in a lot of commercial waste food digesters, anaerobic digestion is relatively odourless which makes this approach suitable for an urban city environment. Our system removes moisture and trace gases such as hydrogen sulphide that gives food waste its unpleasant smell,” explained Assoc Prof Tong.