Having a compost bin is a great way to deal with left over food from lunch boxes, tuck shops and garden clippings from school grounds. This helps reduce the harmful effects that organic waste creates in landfill.
A large proportion of a school’s waste sent to landfill each week is organic. By composting this waste, schools will cut down their waste removal costs and help save the environment.
There are three main composting systems that can be used at school, depending on the type of organic waste your school produces. Alternatively, you can use all three systems to ensure that the organic waste going to landfill is as little as possible.
Compost bin
If you want to recycle mostly garden waste and some food scraps, then a compost bin would suit your school. Compost bins come in all shapes and sizes, from plastic bins readily available at hardware stores, to making your own using untreated recycled wood.
To make compost you need a good mixture of ‘greens’ (grass clippings, vegetable food scraps, teabags, coffee grinds) and a good mixture of ‘browns’ (cardboard, twigs and paper).
Compost is a mixture of organic material made by millions of bugs and bacteria munching through the green and brown material. With the aid of heat and moisture, this material eventually breaks down to form compost. Compost feeds the soil, helps with water retention and encourages earthworms into your garden.
Did you know?
By graphing compost temperature over time you can tell how far along the decomposition has progressed. A well-constructed compost can reach temperatures of over 50 degrees Celsius.
Worm farms
If you want to recycle just vegetable food scraps, worm farming is your best option and provides more interaction and learning opportunities for students. The size of the school will determine how big your worm farm is, and how many you will have. Worm farms are readily available at hardware stores, or you can make your own using an old bath tub.
Tiger worms are usually used for worm farms. After eating the food scraps, the worms make ‘vermi casts’ which is really worm poo, and ‘vermi liquid’, which is worm wee. Both of these contain a lot of good nutrients and can be used in various ways on your garden.
Did you know?
Worms have five hearts and breathe through their skin!
Bokashi
Bokashi systems are great to use in a staff room and are a very easy and effective way of ensuring organic waste doesn’t end up in landfill. You can put food in it that you can’t put in a compost or worm farm, such as, meat, prepared food, cheese and bread. Cared for properly, Bokashi should only have a slight smell of fermented food, and is virtually odourless once the lid is in place.
A product called Compost Zing (approximately $30 for 5kg, which can last up to a year) is mixed with the waste in a two bucket system to help ferment the food. Liquid is collected from the buckets each day, and once full, the bin is rested for two weeks. Your waste will be ready to be added to your garden. Bokashi liquid is a very concentrated liquid fertiliser and can be used on your garden too.
Did you know?
Bokashi (which means ‘fermented organic matter’ in Japanese) ferments waste anaerobically. Your waste is ‘pickled’ and doesn’t decompose until it is put into the soil.
If your school is interested in any of these composting systems, contact the 'Waste Prevention Officer – Schools' via Actionline, phone (09) 486 8600 or email actionline@northshorecity.govt.nz
For further information on compost, worm farms and bokashi visit Create Your Own Eden.
