New Zealand generates almost 2.5 million tonnes of waste each year that is buried in landfill sites. Waste disposed of in this way is an inefficient use of resources, as much of the waste could have been separated and reused, recycled or turned into compost.
Waste management seeks to create a sustainable system where the amount of waste is reduced and the waste that is generated is better managed and efficiently reused or recycled.
Types of waste
We are most familiar with household waste – the rubbish generated from daily life, like food scraps, garden waste, packaging and waste paper. Unless rubbish is separated into different categories for recycling (paper, tins and cans, plastics and glass), waste is put into landfill. Landfill is simply burying all the waste in a large hole in the ground.
Organic matter, such as garden waste (leaves and twigs) and food scraps make up the largest part of the rubbish dumped in our landfill. When buried in the landfill, the organic matter gradually rots away in the absence of oxygen, producing methane gas, a potentially explosive gas that is also harmful to the environment. A toxic liquid (leachate) is also produced, which can contaminate waterways. However, if organic material is kept separate from household rubbish, it biodegrades into something useful – compost. Composting can be done at home, in a traditional compost heap or in a worm farm, to produce fertiliser for gardens. Organic waste can also be recycled at refuse stations and can then be sold as fertiliser.
Businesses and manufacturers produce a huge amount of waste. This can be in the form of solid waste, or industrial effluents, which are disposed of into waterways or the sewerage system. Changes in business practices can greatly reduce the amount of waste generated and make the job of disposing of it more efficient.
The construction industry also generates waste, with large amounts of timber, concrete, plaster and plastic. People are trying to find ways to reprocess and re-use this waste rather than putting in into landfill.
It is also important to make waste disposal and recycling options easily accessible and attractive, to avoid problems with illegal dumping of waste. Illegal dumping often contains hazardous waste, which poses a threat to health and the environment.
These resources support students in levels 1–4 with learning about waste and recycling.