Current Status Of Food Waste Conversion

Latest news on food waste disposal

California’s compost law (SB 1383) has been passed since 2016 and will be implemented in 2022. It will not be implemented until 2024 this year. Vermont and California have already passed this law. In order to convert food waste into fuel, government departments are actively building necessary infrastructure, biogas digesters, and composting devices, but progress is still slow.

For a farmer in Thompson, Conn., with nearby waste incinerators closing and waste disposal bills rising, turning food waste into energy was a win-win situation. On the one hand, food waste accounts for about 25% of the local waste to be processed. On the other hand, the methane generated by the anaerobic digester is used for local heat and electricity supply. The processed digestate can be applied to the land to increase land fertility. However, the construction cost of biogas digesters is high and cannot fully meet the local waste generation. There is still a large amount of food waste to be processed.

Shopping malls in Australia use physical drying technology to evaporate the water in food waste to reduce the weight and volume of the waste, retaining a large amount of nutrients while sterilizing at high temperatures. The processed material is used as bait material and supplied to non-edible fish ponds. Realize resource utilization while harmlessly treating garbage.

Since the concept of carbon reduction and environmental protection was proposed, more and more people have paid attention to the disposal and resource utilization of garbage. At this stage, according to different users, different needs and processing scales, how to choose the appropriate food waste treatment technology to minimize costs and maximize resource recovery and economic benefits has become a question that people are thinking about. Here is a brief inventory of the current relatively mature food waste treatment technologies to provide users with a reference for equipment selection.

Inventory of food waste resource conversion technologies

1.Landfill method

The traditional landfill method mainly treats unsorted garbage. It has the advantages of simplicity and low cost, but the disadvantage is that it occupies a large area and is prone to secondary pollution. Currently, existing landfills bury compressed garbage or ash after incineration, and perform anti-infiltration treatment. After food waste is landfilled, methane produced by anaerobic fermentation is emitted into the air, exacerbating the greenhouse effect. Landfilling is not recommended for food waste disposal.

2.Biological treatment technology

Biological treatment technology uses microorganisms to decompose organic matter in food waste and convert it into H2O, CO2 and small molecular organic matter to reduce waste and produce a small amount of solid matter that can be used as biomass organic fertilizer. Common biological treatment technologies include composting, aerobic fermentation, anaerobic fermentation, biogas digesters, etc.

Anaerobic fermentation operates in a fully enclosed environment under conditions of anoxia or low oxygen, and mainly produces methane, which can be used as clean energy and burned to generate electricity. However, the biogas residue discharged after digestion has a high concentration of organic matter and still needs to be further processed and used as organic fertilizer.

Figure. OWC Food Waste Bio-Dgester equipment appearance and sorting platform

Aerobic fermentation technology stirs garbage and microorganisms evenly and maintains sufficient oxygen to speed up the decomposition of microorganisms. It has the characteristics of stable operation, low cost, and can produce high-quality organic fertilizer substrate. HYHH's OWC Food Waste Bio-Digester uses high-temperature aerobic fermentation technology and intelligent control to ensure that the temperature inside the equipment is stable within the high-activity range of aerobic microorganisms. High-temperature conditions can also disinfect viruses and insect eggs in garbage.

3.Feed technology

The Australian mall mentioned earlier uses dry feed-in-feed technology. Dry feed technology is to dry food waste at 95~120℃ for more than 2 hours to reduce the moisture content of the waste to less than 15%. In addition, there is a protein feed method, which is similar to biological treatment and introduces appropriate microorganisms into the garbage to convert organic matter into protein substances. The product can be used as bait or cattle and sheep feed. This method is more suitable for situations where the source of food waste is stable and its components are simple.

4.Collaborative incineration method

Food waste contains high water content, low heat, and is not easy to burn. Some incineration plants mix pre-treated food waste into municipal waste in an appropriate proportion for collaborative incineration.

5.Simple household compost bucket

With the deepening of environmental awareness and the popularity of the Internet, there are many posts or videos about making home food waste compost bins. Simplified composting technology is used to recycle food waste generated at home, and the decomposed products can be used to fertilize vegetation in the yard. However, due to the selection of microbial agents, the structure of the homemade compost bucket, and the components of the food waste itself, the effects vary greatly, and problems such as strong odor, incomplete decomposition, and long composting time may occur.