Managing waste
Tip out a typical household bin and a surprising thing happens: most of it was never really rubbish. Around half is food and garden scraps that could be compost, and much of the rest is paper, glass and metal that could become new things. So managing waste is less about making it vanish than about not burying value in the first place — and the syllabus\'s real test is not to list the bins, but to evaluate, honestly, whether a given option is actually sustainable.
The interactive book above is the lesson. What follows is a plain recap you can revise from, plus the sources and how this maps to the syllabus.
Audit first, then the hierarchy
A waste audit measures composition — typically about half organics plus a lot of recyclable paper, glass and metal, with little true residual. The waste hierarchy then ranks options: avoid/reduce → reuse → recycle → recover → dispose. The best waste is the waste never made; landfill is the last resort, and each material is matched to the highest rung it allows.
The solid-waste options
Landfill: lined and capped to contain leachate and capture methane, but consumes land and locks materials away. Recycling: saves materials and energy (aluminium ~95%) but needs clean streams, facilities and a market. Composting/organics recovery: turns the biggest bin fraction into compost or biogas (FOGO). Energy recovery: burns residual for electricity but emits CO2 and can compete with recycling.
Evaluating sustainability — the five criteria
The assessable skill is to evaluate a named option against five criteria: energy to produce/recycle, environmental impact of disposal, space for disposal/storage, local facilities, and demand for the recyclate. An option is only as sustainable as its weakest criterion — as the 2018 China import ban showed when Australia lost the market for its mixed recycling.
From bin to system
Managing waste well is a process: know the composition, rank by the hierarchy, match method to material, and evaluate each option\'s sustainability — all aimed at shrinking the ecological footprint. The largest gains sit at the top of the hierarchy, in designing waste out — a circular economy — which is one face of the bigger question of using resources sustainably, the course\'s final chapter.
For HSC students
This powerbook covers the Waste Management thread of Module 8 (Resource Management), framed by the inquiry question how is waste managed? Working through it, you should be able to:
- conduct and interpret a practical investigation of the composition of household or organisational waste;
- outline the management options for different types of solid waste;
- evaluate the sustainability of a named waste-management option, considering the energy used to produce or recycle the waste, the environmental impact of disposal, the space for disposal or storage, the local facilities, and the demand for reused or recycled material.
The recycling example here is one named option you could evaluate — you might equally evaluate landfill, composting or energy recovery against the same five criteria. This chapter builds on the resource-extraction chapter; the next, and final, chapter is on using resources sustainably. Explanations here are original and are a study aid, not a copy of the syllabus.
Sources
- NSW EPA and the National Waste Reports — the waste hierarchy, kerbside waste composition and management options.
- Research on the energy savings of recycling (e.g. aluminium and steel) and on landfill leachate and gas (methane) management.
- Reporting and analysis of China\'s 2018 "National Sword" import policy and Australia\'s subsequent waste-export bans and domestic-recycling investment.
- NSW programs — Return and Earn container deposit scheme and the rollout of FOGO (food organics, garden organics) collections.
- Circular-economy and waste-to-energy assessments weighing the trade-offs of each option.
- NSW NESA Earth and Environmental Science Stage 6 Syllabus (2017) — used only to scope the Module 8 content; explanations above are original.
The question was never how to make waste disappear — it was how to stop wasting it. Know what is in the bin, rank the options, and weigh each one honestly, and "rubbish" turns back into resources.