This experiment enables students to record the decomposition rate of a range of products sold as Compostable and Biodegradable
Biodegradable materials will eventually be broken-down by bacteria or other living organisms, while "compostable" products
will decompose under aerobic conditions with controlled temperature and humidity.
There are two types of compostable material. Most compostable products should to break down in 2-3 months in industrial facilities. Home composting labels indicate that the material can be composted at the lower temperatures
that occur in home composting bins.
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Compostable bags are often sold to be placed in kitchen caddies to collect kitchen scraps
for composting. When full of kitchen waste the bag is then carried to the compost bin dropped in avoiding the mess that might be associated with using an unlined caddy. Compostable bags can also be purchased for picking up dog mess. Compostable
Cling film is also available
Disposable Compostable plates, bowls, food and drink containers sold as composted are designed to be composting in municipal composting facilities not cool home composting systems.
If a Hot Home composting
system e.g. Hotbin, Green Johanna, Jorra , is available the effectiveness of this bin should be compared with the more common cool composting systems.
Each of the chosen compostable materials is placed in its own labelled poly mesh produce bags (these
are usually made from knitted plastic and have a drawstring closure. Net bags are used by farmers, gardeners e.g. onion bags (A 310mm wide x 350mm long net bags are available new from Polybags at about £19 for 100) .
Each food bag
should be buried in a compost bin or wormery, with a length of string attached to the draw string and reaching up to the top of the compost bin so it can be retrieved to be examined weekly.
The depth at which the bag is buried in the bin should
be noted so that it can be returned to the same position once photographed
Each week the compost bin temperature should be recorded. The bag should be removed monthly and the contents of each bag placed on white card, marked
with the date and bin temperature, and photographed to record the rate of decomposition and the effect on it by composting temperature.