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Ultrafast Conversion of Food Waste to Biofertilizers
Over the last decade, food waste in Singapore grew by 20% and about 665,000 tonnes of food waste were generated in 2020. Currently, about 81% of food waste is incinerated together with other municipal wastes for volume reduction. As a readily available, abundant, and inexpensive resource, food waste has plenty of untapped potential to be converted into useful resources due to its richness in organic matter and nutrients. The technology provides an easy and holistic approach for food waste management towards quick, odourless, zero-solid disposal.
Developed on the basis of zero solid discharge-driven resource recovery from food waste, i.e. food waste to biofertilizers, heterogeneous food waste is subjected to 8-10 hours of ultrafast hydrolysis mediated by a fungal mash rich in various hydrolytic enzymes, which is also produced from food waste at very low costs. After a solid-liquid separation, the produced liquids and solids are harvested as biofertilizers that could meet the Chinese Standards for organic fertilizers, with nearly zero solid discharge. This technology can also be extended to bioenergy production (e.g. bioethanol and biomethane) from food waste.
The first pilot-scale prototype has been built with the treatment capacity of 100 kg food waste per batch. The team is seeking collaboration opportunities with potential partners for further engineering development.
Technology Features, Specifications and Advantages
The technology consists of a reactor that comprises a unit for fungal mash production, an enzymatic hydrolysis unit and a liquid/solid separation unit. Food waste is first mixed with a fungal mash and passed into the fungal enzymatic hydrolysis unit. After the hydrolysis reaction, the hydrolysate is passed through the liquid/solid separation unit. The solids obtained with adequate nitrogen, phosphorus and potassium contents are harvested as solid biofertilizer, while the liquid rich in various nutrients, fatty acids and microelements can be directly used as liquid biofertilizer.
Some features of the technology include:
- Ultrafast conversion of food waste to biofertilizers (8 to 10 hours) by using in-situ produced fugal mash rich in various hydrolytic enzymes, with nearly zero-solid discharge and a small footprint.
- No generation of secondary pollutants e.g. smell, odor, exhausted gases etc.
- Economically viable when compared to the processes using highly expensive commercial enzymes
- Compact and modularized design with low noise
- Has the ability to extend to production of bioenergy e.g. bioethanol and biomethane
Potential applications include (but are not limited to):
- Food court/restaurant food waste
- Bakery waste
- Organic waste
- Other waste streams, i.e. wastewater sludge
The global consumption of agricultural fertilizer had hit 200 million tons per year, and biofertilizer produced from food waste as an alternative to chemical fertilizer would have a great market potential. About 1.6 billion tons of food waste were lost or wasted per year globally. Theoretically about 650 million tons of solid biofertilizer and 1.28 billion tons of liquid biofertilizer would be produced yearly from the global food waste with a water content of 80%, which could substitute chemical fertilizer to sustain rapidly growing agricultural needs.
Given the huge amount of food waste generated, there is a promising and highly demanded market for food waste valorization with the ultimate goal of zero solid discharge. The potential economic and social benefits of this technology may come from different aspects, e.g. commercial value of produced biofertilizers, relieving the pressures on incineration, minimized generation of secondary pollutants, soil quality improvement etc.