Resource Use and the Management of Solid Domestic Waste

Classifying resources. A renewable resource is replaced by natural processes at a rate comparable to its use — timber, fish, fresh water. A non-renewable resource is formed so slowly that it is effectively fixed on human timescales — fossil fuels, most minerals. A replenishable resource is one that flows continuously, such as solar radiation or wind. The classification is not a property of the substance alone: a renewable resource harvested faster than it regenerates behaves exactly like a non-renewable one, which is the situation of many fisheries, aquifers and soils. This is why the concept of natural income — the yield that can be taken without reducing the natural capital that produces it — is more useful than the label.

Solid domestic waste. The composition of household waste changes predictably with income. Low-income cities produce waste that is largely organic and dense; high-income cities produce more paper, plastic, packaging and electronic waste, and a smaller organic fraction. This matters because it determines which strategy works: composting and anaerobic digestion suit an organic-rich stream, while separation at source and producer responsibility suit a packaging-rich stream.

The waste hierarchy. In order of priority: reduce, reuse, recycle, recover energy, and finally dispose. The ordering has a reason that is often missed. Recycling ranks only third because the process itself consumes energy, water and transport, and because most materials degrade in quality with each cycle — plastic and paper are generally downcycled rather than recycled indefinitely, whereas glass, aluminium and steel can be recycled with little loss. Reduction ranks first because it is the only step that creates no material flow to manage at all. A programme that promotes recycling alone begins at the third rung.

Landfill and incineration compared. Landfill is cheap to build and needs little technology, but consumes large areas permanently, produces leachate that can contaminate groundwater unless the site is lined and drained, and generates methane as organic matter decomposes anaerobically — a gas with roughly twenty-eight times the warming potential of carbon dioxide, so an uncapped site is a significant climate source. Incineration reduces waste volume by about ninety per cent, needs little land and can generate electricity, but requires very high capital investment, emits dioxins and heavy metals unless flue gases are cleaned to a high standard, and leaves bottom ash and fly ash that must themselves be landfilled, the fly ash as hazardous waste. The strongest argument against treating incineration as the solution is structural: a plant must be fed a steady stream of waste for two or three decades to repay its capital, so a city that builds one acquires an incentive to maintain waste volumes, which conflicts directly with the top two rungs of the hierarchy.

Strategies that address the cause. Reducing the volume of waste generated means acting before the waste exists: extended producer responsibility, which makes manufacturers responsible for the end of life of what they sell; design for durability, repairability and disassembly; deposit-return schemes; charges on single-use packaging; and pay-as-you-throw charging, which prices household waste by weight or volume so the incentive reaches the person making the decision. Changing the composition of the stream — separating organics for composting or digestion — matters as much as changing its volume, because organic matter in landfill is the source of both leachate and methane.