Daily Archives: February 23, 2017

New Food Composter at DC

Posted by Peter MUIR

Within the past few weeks Discovery College has had a new food composter in the school cafeteria, and the Green Cobras – our schools environmental group – have been working to spread awareness how students can act to have the machine working to its full potential.

As land is a hot commodity in Hong Kong, there is little space for landfill, which is where all of our waste goes. Food waste is a major constituent of the solid waste in Hong Kong’s currently existing landfills. According to the HK Government’s Environmental Protection Department, in 2015 Hong Kong produced 382 tonnes of food waste daily, which amounts to about half a kilogram per person per day.  As food is highly degradable, it can easily cause odour and hygiene problems.


In addition to issues with taking up valuable landfill space, there is another important reason for keeping our food waste out of landfills.  When food and other materials sit in landfills most of the time they are not exposed to oxygen. This means that it breaks down anaerobically and methane, a greenhouse gas with the warming potential 21 times that of carbon dioxide, is produced.

By composting the food with our new machine, we are producing fertilizer that can be used in gardens, we are reducing greenhouse gas emissions and therefore our collective global footprint, and we are reducing the waste we send to landfills. It is a win-win situation!

The composter speeds up the natural decomposition rate to 24 hours. There are rotating arms inside the machine that keep the waste in motion and ensure that it is exposed to oxygen. The composter also makes use of microorganisms living inside the machine to break down the food waste. In the process the temperature of the composter is raised to 75˚C in order to eliminate all harmful bacteria. This process results in a 80-90% reduction rate of the food waste. More information on the composter can be found here.

The Green Cobras plan to use the fertiliser produced by the composter to help grow plants in the new planter boxes on level five of the school. If the plants grow well, we might even be able to eat some of our own home grown vegetables in the cafeteria! If excess fertilizer is produced, we will explore the option of selling fertilizer to the DB community and use any funds raised to go towards other initiatives to make our school as environmentally friendly as possible.

All of the DC community is encouraged to separate their food waste from their plates, cutlery and plastic wrappers so that we can use the composter to its maximum potential.

The Green Cobras meet every Friday lunchtime in room 2208. New members are more than welcome! For further enquiries contact Anne 16gassera1@dc.edu.hk.